1979 

National Cancer Institute 

CARCINOGENESIS 

Technical Report Series 

No. 129 

BIOASSAY OF 

TRIMETHYLTHIOUREA 

FOR POSSIBLE CARCINOGENICITY 

CAS No. 2489-77-2 

NCI-CG-TR-129 

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE 

Public Health Service 

National Institutes of Health 

BIOASSAY OF
 

TRIMETHYLTHIOUREA
 

FOR POSSIBLE CARCINOGENICITY
 

Carcinogenesis Testing Program
 

Division of Cancer Cause and Prevention
 

National Cancer Institute
 

National Institutes of Health
 

Bethesda, Maryland 20014
 

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
 

Public Health Service
 

National Institutes of Health
 

DHEW Publication No. (NIH) 79-1384
 

REPORT ON THE BIOASSAY OF TRIMETHYLTHIOUREA
 

FOR POSSIBLE CARCINOGENICITY
 

CARCINOGENESIS TESTING PROGRAM
 

DIVISION OF CANCER CAUSE AND PREVENTION
 

NATIONAL CANCER INSTITUTE, NATIONAL INSTITUTES OF HEALTH
 

FOREWORD: This report presents the results of the bioassay of
 

trimethylthiourea conducted for the Carcinogenesis Testing Program,
 

Division of Cancer Cause and Prevention, National Cancer Institute
 

(NCI), National Institutes of Health, Bethesda, Maryland. This is
 

one of a series of experiments designed to determine whether selected
 

chemicals have the capacity to produce cancer in animals. Negative
 

results, in which the test animals do not have a significantly
 

greater incidence of cancer than control animals, do not necessarily
 

mean the test chemical is not a carcinogen because the experiments
 

are conducted under a limited set of circumstances. Positive results
 

demonstrate that the test chemical is carcinogenic for animals under
 

the conditions of the test and indicate a potential risk to man.
 

The actual determination of the risk to man from animal carcinogens
 

requires a wider analysis.
 

CONTRIBUTORS: This bioassay of trimethylthiourea was conducted by
 

Litton Bionetics, Inc., Bethesda, Maryland, initially under direct
 

contract to the NCI and currently under a subcontract to Tracer
 

Jitco, Inc., prime contractor for the NCI Carcinogenesis Testing
 

Program.
 

The experimental design was determined by the NCI Project Officers, Dr. N. P. Page (1,2), Dr. E. K. Weisburger (1) and Dr. J. H.
 

Weisburger (1,3). The principal investigators for the contract were
 

Dr. F. M. Garner (4,5) and Dr. B. M. Ulland (4,5). Mr. S. Johnson
 

(4) was the coprincipal investigator for the contract. Animal treatment and observation were supervised by Mr. R. Cypher (4), Mr. D. S.
 

Howard (4) and Mr. H. D. Thornett (4); Mr. H. Paulin (4) analyzed
 

dosed feed mixtures. Ms. J. Blalock (4) was responsible for data
 

collection and assembly.
 

Histopathologic examinations were performed by Dr. F. M. Garner
 

(4) at Litton Bionetics, Inc., the pathology narratives were written
 

by Dr. F. M. Garner (4), and the diagnoses included in this report
 

represent the interpretation of this pathologist. Histopathology
 

findings and reports were reviewed by Dr. R. L. Schueler (6).
 

ill
 
Compilation of individual animal survival, pathology, and summary tables was performed by EG&G Mason Research Institute (7); the
 

statistical analysis was performed by Mr. W. W. Belew (8,9) and Mr.
 

R. M. Helfand (8), using methods selected for the Carcinogenesis
 

Testing Program by Dr. J. J. Gart (10).
 

This report was prepared at METREK, a Division of The MITRE Corporation (8) under the direction of the NCI. Those responsible for
 

this report at METREK are the project coordinator, Dr. L. W. Thomas
 

(8), task leader Ms. P. Walker (8), senior biologist Mr. M. Morse
 

(8), biochemist Mr. S. C. Drill (8), chemist Dr. N. Zimmerman (8),
 

and technical editor Ms. P. A. Miller (8). The final report was
 

reviewed by members of the participating organizations.
 

The following other scientists at the National Cancer Institute
 

were responsible for evaluating the bioassay experiment, interpreting
 

the results, and reporting the findings: Dr. K. C. Chu (1), Dr. C.
 

Cueto, Jr. (1), Dr. J. F. Douglas (1), Dr. D. G. Goodman (1,11), Dr.
 

R. A. Griesemer (1), Dr. M. H. Levitt (1), Dr. H. A. Milman (1), Dr.
 

T. W. Orme (1), Dr. R. A. Squire (1,12), Dr. S. F. Stinson (1), Dr.
 

J. M. Ward (1), and Dr. C. E. Whitmire (1).
 

1.	 Carcinogenesis Testing Program, Division of Cancer Cause and
 

Prevention, National Cancer Institute, National Institutes of
 

Health, Bethesda, Maryland.
 

2.	 Now with the U.S. Environmental Protection Agency, 401 M Street
 

S.W. , Washington, D-.C.
 

3.	 Now with the Naylor Dana Institute for Disease Prevention, American Health Foundation, Hammon House Road, Valhalla, New York.
 

4.	 Litton Bionetics, Inc., 5516 Nicholson Lane, Kensington, Maryland.
 

5.	 No wit w h Hazleton Laboratories America, Inc., 9200 Leesburg
 

Turnpike, Vienna, Virginia,
 

6.	 Tracer Jitco, Inc., 1776 East Jefferson Street, Rockville,
 

Maryland.
 

7.	 EG&G Mason Research Institute, 1530 East Jefferson Street,
 

Rockville, Maryland.
 

8.	 Th MITR e E Corporation, METREK Division, 1820 Dolley Madison
 

Boulevard, McLean, Virginia.
 

iv
 
9.	 No wit w h the Solar Energy Research Institute, Cole Boulevard,
 

Golden, Colorado.
 

10.	 Mathematical Statistics and Applied Mathematics Section, Biometry
 

Branch, Field Studies and Statistics Program, Division of Cancer
 

Cause and Prevention, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
 

11.	 Now with Clement Associates, Inc., 1010 Wisconsin Avenue, N.W.,
 

Washington, D.C.
 

12.	 Now with the Division of Comparative Medicine, Johns Hopkins
 

University, School of Medicine, Traylor Building, Baltimore,
 

Maryland.
 

v
 

SUMMARY
 

A bioassay for the possible carcinogenicity of trimethylthiourea
 

was conducted using Fischer 344 rats and B6C3F1 mice. A mixture
 

containing 80 percent trimethylthiourea and 15 percent dimethylthiourea was administered in the feed, at either of two concentrations,
 

to groups of 50 male and 50 female animals of each species. Twenty
 

animals of each sex and species were placed on test as controls.
 

The high and low dietary concentrations of trimethylthiourea were,
 

respectively, 500 and 250 ppm for rats and 1000 and 500 ppm for mice.
 

The compound was administered in the diet for 77 weeks, followed by
 

an observation period of 29 weeks for rats and 14 weeks for mice.
 

There were no significant positive associations between the
 

dosage of trimethylthiourea administered and mortality in rats or
 

mice of either sex. Adequate numbers of animals in all groups survived sufficiently long to be at risk from late-developing tumors.
 

For high dose female rats and for dosed mice of both sexes, compound-


related mean body weight depression was observed, indicating that
 

the dosages of trimethylthiourea administered to these animals may
 

have approximated the maximum tolerated dosages. Since no mean body
 

weight depression relative to controls, no significant accelerated
 

mortality, and no other signs of toxicity were associated with
 

administration of trimethylthiourea to male rats, it is possible that
 

these animals may have been able to tolerate a higher dietary concentration.
 

The incidences of follicular-cell carcinomas of the thyroid in
 

female rats were dose-related, and there was a significant difference
 

between the incidences in the high dose and control. This same
 

relationship was established for the combination of follicular-cell
 

carcinomas and follicular-cell adenomas in female rats.
 

Under the conditions of this bioassay, dietary administration
 

of trimethylthiourea was carcinogenic in female Fischer 344 rats,
 

inducing follicular-cell carcinomas of the thyroid. There was not
 

sufficient evidence for the carcinogenicity of the compound in male
 

Fischer 344 rats or in B6C3F1 mice of either sex.
 

vii
 

TABLE OF CONTENTS
 

Page
 

I. INTRODUCTION 1
 

II. MATERIALS AND METHODS 4
 

A. Chemicals 4
 

B. Dietary Preparation 4
 

C. Animals 5
 

D. Animal Maintenance 6
 

E. Selection of Initial Concentrations 7
 

F. Experimental Design 9
 

G. Clinical and Histopathologic Examinations 12
 

H. Data Recording and Statistical Analyses 14
 

III. CHRONIC TESTING RESULTS: RATS 19
 

A. Body Weights and Clinical Observations 19
 

B. Survival 19
 

C. Pathology 19
 

D. Statistical Analyses of Results 23
 

IV. CHRONIC TESTING RESULTS: MICE 31
 

A. Body Weights and Clinical Observations 31
 

B. Survival 31
 

C. Pathology 34
 

D. Statistical Analyses of Results 34
 

V. DISCUSSION 38
 

VI. BIBLIOGRAPHY 40
 

APPENDIX A SUMMARY OF THE INCIDENCE OF NEOPLASMS IN
 

RATS TREATED WITH TRIMETHYLTHIOUREA A-l
 

APPENDIX B SUMMARY OF THE INCIDENCE OF NEOPLASMS IN
 

MICE TREATED WITH TRIMETHYLTHIOUREA B-l
 

APPENDIX C SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC
 

LESIONS IN RATS TREATED WITH TRIMETHYLTHIOUREA C-l
 

APPENDIX D SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC
 

LESIONS IN MICE TREATED WITH TRIMETHYLTHIOUREA D-l
 

ix
 
LIST OF ILLUSTRATIONS 

Figure Number Page 

1 CHEMICAL STRUCTURE OF TRIMETHYLTHIOUREA 2 

2 GROWTH CURVES FOR TRIMETHYLTHIOUREA CHRONIC 

STUDY RATS 20 

SURVIVAL COMPARISONS OF

CHRONIC STUDY RATS

 TRIMETHYLTHIOUREA 

 21 

GROWTH CURVES FOR TRIMETHYLTHIOUREA

STUDY MICE

 CHRONIC 

 32 

SURVIVAL COMPARISONS OF

CHRONIC STUDY MICE

 TRIMETHYLTHIOUREA 

 33 

LIST OF TABLES 

Table Number Page 

DESIGN SUMMARY FOR FISCHER 344 RATS— 

TRIMETHYLTHIOUREA FEEDING EXPERIMENT 10 

DESIGN SUMMARY FOR B6C3F1 MICE—TRIMETHYLTHIOUREA FEEDING EXPERIMENT 11 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS 

AT SPECIFIC SITES IN MALE RATS TREATED WITH 

TRIMETHYLTHIOUREA 24 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS 

AT SPECIFIC SITES IN FEMALE RATS TREATED 

WITH TRIMETHYLTHIOUREA 26 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS 

AT SPECIFIC SITES IN MALE MICE TREATED WITH 

TRIMETHYLTHIOUREA 35 

Al SUMMARY OF THE INCIDENCE OF NEOPLASMS IN 

MALE RATS TREATED WITH TRIMETHYLTHIOUREA A-3 

A2 SUMMARY OF THE INCIDENCE OF NEOPLASMS IN 

FEMALE RATS TREATED WITH TRIMETHYLTHIOUREA A-7 
LIST OF TABLES (Concluded) 

Table Number Page 

Bl SUMMARY OF THE INCIDENCE OF NEOPLASMS IN 

MALE MICE TREATED WITH TRIMETHYLTHIOUREA B-3 

B2 SUMMARY OF THE INCIDENCE OF NEOPLASMS IN 

FEMALE MICE TREATED WITH TRIMETHYLTHIOUREA B-6 

Cl SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC 

LESIONS IN MALE RATS TREATED WITH TRIMETHYLTHIOUREA C-3 

C2 SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC 

LESIONS IN FEMALE RATS TREATED WITH TRIMETHYLTHIOUREA C-6 

Dl SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC 

LESIONS IN MALE MICE TREATED WITH TRIMETHYLTHIOUREA D-3 

D2 SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC 

LESIONS IN FEMALE MICE TREATED WITH TRIMETHYLTHIOUREA D-6 

XI
 

I. INTRODUCTION
 

Trimethylthiourea (Figure 1) (NCI No. C02186), useful in a wide
 

variety of industrial applications, was selected for bioassay by the
 

National Cancer Institute because it is a derivative of thiourea, a
 

liver carcinogen in Osborne-Mendel rats (Radomski et al., 1965).
 

The Chemical Abstracts Service (CAS) Ninth Collective Index
 

(1977) name for this compound is trimethylthiourea. It is also
 

called N,N,N'-trimethylthiourea and 1,1,3-trimethyl-2-thiourea.
 

Trimethylthiourea can be used to accelerate the vulcanization of
 

various types of rubber, including polychloropropene and diene-nitrile
 

rubber (Langlade, 1976; Starmer, 1976a,b). Trimethylthiourea has also
 

been used as a component of adhesives (Hauser and Malofsky, 1974;
 

Ohashi et al. , 1971) and degradable polyethylene films (Kirkpatrick,
 

1973); as an intermediate in the synthesis of substituted acyl derivatives of tt-aminoacylpenicillins (Rosati, 1973) and phthalocyanine
 

pigments (Inuzuka et al., 1976); and as an inhibitor of ozone fading
 

of dyed polyamides (Lofquist and Saunders, 1974); in a mixture with
 

an aqueous acid to emboss nylon carpet by shrinking certain areas
 

(Palmer and Conger, 1974); and to prepare an antishrinkage treatment
 

for keratinous fibers (e.g., wool) (Vandenberg and Willis, 1974).
 

Specific production data for trimethylthiourea are not available;
 

however, this compound is produced in commercial quantities (in excess
 

*
 

The CAS registry number is 2489-77-2.
 
/

CH3 

CH3—HN—C—N 

FIGURE 1 

CHEMICAL STRUCTURE OF TRIMETHYLTHIOUREA 
of 1000 pounds or $1000 in value annually) by one U.S. company (Stanford Research Institute, 1977).
 

A potential for exposure to trimethylthiourea may exist among
 

workers in a variety of industries, including the chemical, elastomer,
 

textile and dye, and pharmaceutical manufacturing industries.
 
II. MATERIALS AND METHODS
 

A. Chemicals
 

Trimethylthiourea was purchased from R. T. Vanderbilt Co., Inc.,
 

Norwalk, Connecticut. Chemical analysis was performed by Litton Bionetics, Inc., Kensington, Maryland. According to the manufacturer's
 

specifications, the product was 80 percent trimethylthiourea, 15
 

percent 1,3-dimethyl-2-thiourea and 5 percent Zeolex 80. Thin-layer
 

chromatography was performed utilizing two solvent systems (i.e.,
 

benzene:acetone and chloroform:acetone). Each plate was visualized
 

with ultraviolet and visible light, iodine vapor, and Crete's reagent
 

spray. Two spots were apparent on each plate, one major spot and
 

one minor spot that was positive to Grote's reagent and identified
 

as 1,3-dimethyl-2-thiourea. The results of infrared and nuclear
 

magnetic resonance analyses were consistent with those expected on
 

the basis of the structure of the compound.
 

Throughout this report the term trimethylthiourea is used to
 

represent this material.
 

B. Dietary Preparation
 

The basal laboratory diet for both dosed and control animals
 

consisted of Wayne Lab-Blox (Allied Mills, Inc., Chicago, Illinois).
 

Trimethylthiourea was administered to the dosed animals as a component
 

of the diet.
 

The chemical was removed from its container and a proper amount
 

was blended with an aliquot of the ground feed using a mortar and
 
pestle. Once visual homogeneity was attained, the mixture v<is placed
 

in a 6 kg capacity Patterson-Ke1ley standard model twin-shell stainless steel V-blender along with the remainder of the fe<.i to be
 

prepared. After 20 minutes of blending, the mixtures were p^aceo i:
 

double plastic bags and stored in the dark at 4°C. The mixture was
 

prepared once weekly.
 

Dosed feed preparations containing 1250 and 625 ppm of trimethylthiourea were analyzed spectrophotometrically. The mean result
 

immediately after preparation was 106.7 percent of theoretical
 

(ranging from 97.6 to 124.4 percent), including correction for the
 

analytical method of recovery used. After 10 days, at ambient room
 

temperature, the mean result was 102.9 percent of theoretical (ranging
 

from 100.3 to 108.0 percent), including correction for the analytical
 

method of recovery used.
 

C. Animals
 

Two animal species, Fischer 344 rats and B6C3F1 mice, were
 

obtained through contracts of the Division of Cancer Treatment,
 

National Cancer Institute. All rats and mice were supplied by
 

Charles River Breeding Laboratories, Inc., Wilmington, Massachusetts.
 

Rats and mice were approximately 4 weeks old when received. Upon
 

receipt, animals were examined for visible signs of disease or parasites. Obviously ill or runted animals were culled. The remainir.^
 

animals were quarantined for 2 weeks prior to initiation of test.
 
Animals which did not manifest clinical signs of disease were placed
 

on test at this time. Animals were assigned to groups and distributed
 

among cages so that the average body weight per cage was approximately
 

equal for a given species and sex.
 

D. Animal Maintenance
 

All animals were housed by species in temperature- and humidity-


controlled rooms. The temperature range was 22° to 26°C and the
 

relative humidity was maintained between 45 and 55 percent. Incoming
 

air was filtered through HEPA filters (Flanders Filters, McLean, Virginia) at a rate of 12 to 15 complete changes of room air per hour.
 

Fluorescent lighting was provided 8 hours per day (9:00 a.m. to 5:00
 

p.m.).
 

All rats were housed four per cage by sex and all mice were
 

housed five per cage by sex. Throughout the study dosed and control
 

animals of both species were housed in polycarbonate cages (Lab
 

Products, Inc., Garfield, New Jersey) suspended from aluminum racks.
 

Racks were fitted with a continuous piece of stainless steel mesh
 

over which a sheet of filter paper was firmly secured. Filter paper
 

was changed at 2-week intervals, when the racks were sanitized.
 

• ®
 Clean cages and bedding were provided twice weekly. Ab-sorb-dri
 

hardwood chip bedding (Wilner Wood Products Company, Norway, Maine)
 

was used in polycarbonate cages for the entire bioassay.
 

Acidulated water (pH 2.5) was supplied to animals in water bottles filled by an automated metering device that was checked daily
 
for diluting accuracy. Water bottles were changed and washed twice
 

weekly and sipper tubes were washed at weekly intervals. During the
 

period of chemical administration, dosed and control animals received
 

(R)
 treated or untreated Wayne Lab-Blox meal as appropriate. The feed
 

was supplied in hanging stainless steel hoppers which were refilled
 

three times per week and sanitized weekly. Food and water were
 

available ad libitum for both species.
 

All dosed and control rats were housed in a room with other rats
 

receiving diets containing Michler's ketone (90-94-8); p-chloroaniline (106-47-8); and p-nitrosodiphenylamine (156-10-5).
 

All dosed and control mice were housed in a room with other mice
 

receiving diets containing Michler's ketone (90-94-8); 4,4'-methylenebis(N,N-dimethyl)-benzenamine (101-61-1); l-phenyl-2-thiourea (103-85­

5); 3-chloro-p-toluidine (95-74-9); dibutyltin diacetate (1067-33-0);
 

2-nitro-p-phenylenediamine (5307-14-2); p-chloroaniline (106-47-8);
 

5-chloro-o-toluidine (95-79-4); and p-aminodiphenylamine (2198-59-6).
 

E. Selection of Initial Concentrations
 

In order to establish the maximum tolerated concentrations of
 

trimethylthiourea for administration to dosed animals in the chronic
 

studies, subchronic toxicity tests were conducted with both rats and
 

mice. Rats were distributed among six groups, each consisting of
 

five males and five females. Trimethylthiourea was incorporated into
 

*
 

CAS registry numbers are given in parentheses.
 
t.'<° basal laboratory diet and supplied ad libitum to five of the six
 

rat groups in concentrations of 315, 680, 1465, 3155, and 6800 ppm.
 

The remaining rat group served as a control group, receiving only the
 

basal laboratory diet.
 

Mice were distributed among nine groups, each consisting of five
 

males and five females. Trimethylthiourea was incorporated into the
 

basal laboratory diet and supplied ad libitum to seven of the nine
 

mouse groups in concentrations of 370, 550, 810, 1180, 1740, 2550
 

and 5500 ppm. The remaining two mouse groups served as control
 

groups, receiving only the basal laboratory diet.
 

The dosed dietary preparations were administered for a period
 

of 4 weeks, followed by a 2-week observation period during which all
 

ariiFals were fed the basal laboratory diet. Individual body weights
 

and food consumption data were recorded twice weekly throughout the
 

study Upon termination of the observation period, all survivors
 

were sacrificed and necropsied.
 

Af the end of the subchronic test, mean body weight gain among
 

male rats dosed with 315 ppm was 2 percent greater than the mean body
 

weight gain of their controls, while female rats receiving the same
 

concent'-^tioti displayed a mean body weight gain 4 percent greater
 

than that of their controls. Mean body weight gain among male rats
 

dosed with 680 ppm was 15 percent less than that of their controls,
 

while female rats receiving the same concentrations displayed a mean
 
body weight gain 11 percent less than that of their controls. No
 

deaths were reported among male or female rats. The high concentration selected for administration to dosed rats in the chronic bioassay was 500 ppm.
 

At the end of the subchronic test, mean body weight gain among
 

male mice dosed with 810 ppm was 3 percent less than the mean body
 

weight gain of their controls, while female mice receiving the same
 

concentration displayed a mean body weight gain 6 percent less than
 

that of their controls. Mean body weight gain among male mice dosed
 

with 1180 ppm was 14 percent less than that of their controls, while
 

female mice receiving the same concentration displayed a mean body
 

weight gain 10 percent less than that of their controls. No deaths
 

were reported among male or female mice. The high concentration selected for administration to dosed mice in the chronic bioassay was
 

1000 ppm.
 

F. Experimental Design
 

The experimental design parameters for the chronic study (species, sex, group size, concentrations administered, and duration of
 

treated and untreated observation periods) are summarized in Tables
 

1 and 2.
 

All rats were approximately 6 weeks old at the time the test
 

was initiated, and were placed on test simultaneously. The dietary
 

concentrations of trimethylthiourea utilized for rats were 500 and
 
TABLE 1
 

DESIGN SUMMARY FOR FISCHER 344 RATS
 

TRIMETHYLTHIOUREA FEEDING EXPERIMENT
 

INITIAL 

GROUP TRIMETHYLTHIOUREA 

SIZE CONCENTRATION3 

MALE
 

CONTROL 20 0
 

LOW DOSE 50 250
 

0
 

HIGH DOSE 50 500
 

0
 

FEMALE
 

CONTROL 20 0
 

LOW DOSE 50 250
 

0
 

HIGH DOSE 50 500
 

0
 

Concentrations given in parts per million.
 

OBSERVATION PERIOD
 

TREATED UNTREATED
 

(WEEKS) (WEEKS)
 

0 106
 

77
 

29
 

77
 

29
 

0 106
 

77
 

29
 

77
 

29
 

10
 
TABLE 2
 

DESIGN SUMMARY FOR B6C3F1 MICE
 

TRIMETHYLTHIOUREA FEEDING EXPERIMENT
 

INITIAL OBSERVATION PERIOD 

GROUP TRIMETHYLTHIOUREA TREATED UNTREATED 

SIZE CONCENTRATION3 (WEEKS) (WEEKS) 

MALE 

CONTROL 20 0 0 91 

LOW DOSE 50 500 77 

0 14 

HIGH DOSE 50 1000 77 

0 14 

FEMALE 

CONTROL 20 0 0 91 

LOW DOSE 50 500 77 

0 14 

HIGH DOSE 50 1000 77 

0 14 

Concentrations given in parts per million. 

11
 
250 ppm. Throughout this report, those rats receiving the former
 

concentration ute referred to as the high dose groups and those
 

receiving the latter concentration are referred to as the low dose
 

groups. Dosed rats were supplied with feed containing trimethylthiourea for 11 weeks followed by a 29-week observation period.
 

All mice were approximately 6 weeks old at the time the test was
 

initiated, and were placed on test simultaneously. The concentrations of trimethylthiourea utilized for mice were 1000 and 500 ppm.
 

Througho this report, those mice receiving the former concentration
 

are referred to as the high dose groups and those receiving the latter
 

concentration are referred to as the low dose groups. Dosed mice were
 

suppl-n vith feed containing trimethylthiourea for 77 weeks followed
 

by a 14 eek observation period.
 

G. Clinical and Histopathologic Examinations
 

Anii.ials were weighed immediately prior to initiation of the experiment. From the first day, all animals were inspected twice daily
 

for mortality. Food consumption data were collected at monthly intervals from 20 percent of the animals in each group. Body weights were
 

recorded once a week for the first 6 weeks, every 2 weeks for the next
 

12 weeks, and once a month for the remainder of the bioassay.
 

All moribund animals or animals that developed large, palpable
 

masses that jeopardized their health were sacrificed. A necropsy was
 

performed on each animal regardless of whether it died, was sacrificed
 

12
 
when moribund, or was sacrificed at the end of the bioassay. The
 

animals were euthanized by carbon dioxide asphyxiation, and were
 

immediately necropsied. The histopathologic examination consisted
 

of gross and microscopic examination of all major tissues, organs,
 

or gross lesions taken from sacrificed animals and, whenever possible,
 

from animals found dead.
 

Tissues were preserved in a 10 percent neutral buffered formalin
 

solution, embedded in paraffin, sectioned, and stained with hematoxylin and eosin prior to microscopic examination.
 

Slides were prepared from the following tissues: skin, subcutaneous tissue, lungs and bronchi, trachea, bone marrow, spleen, lymph
 

nodes, thymus, heart, salivary gland, liver, gallbladder (mice), pancreas, esophagus, stomach, small intestine, large intestine, kidney,
 

urinary bladder, pituitary, adrenal, thyroid, parathyroid, testis,
 

prostate, brain, uterus, mammary gland, tunica vaginalis, and ovary.
 

A few tissues were not examined for some animals, particularly
 

for those that died early. Also, some animals were missing, cannibalized, or judged to be in such an advanced state of autolysis as to
 

preclude histopathologic interpretation. Thus, the number of animals
 

for which particular organs, tissues, or lesions were examined microscopically varies and does not necessarily represent the number of
 

animals that were recorded in each group at the time that the test
 

was initiated.
 

13
 
H. Data Recording and Statistical Analyses
 

Pertinent data on this experiment have been recorded in an automatic data processing system, the Carcinogenesis Bioassay Data System
 

(Linhart et al., 1974). The data elements include descriptive information on the chemicals, animals, experimental design, clinical observations, survival, body weight, and individual pathologic results,
 

as recommended by the International Union Against Cancer (Berenblum,
 

1969). Data tables were generated for verification of data transcription and for statistical review.
 

These data were analyzed using the statistical techniques described in this section. Those analyses of the experimental results
 

that bear on the possibility of carcinogenicity are discussed in the
 

statistical narrative sections.
 

Probabilities of survival were estimated by the product-limit
 

procedure of Kaplan and Meier (1958) and are presented in this report
 

in the form of graphs. Animals were statistically censored as of the
 

time that they died of other than natural causes or were found to be
 

missing; animals dying from natural causes were not statistically
 

censored. Statistical analyses for a possible dose-related effect
 

on survival used the method of Cox (1972) when testing two groups for
 

equality and used Tarone's (1975) extensions of Cox's methods when
 

testing a dose-related trend. One-tailed P-values have been reported
 

for all tests except the departure from linearity test, which is only
 

reported when its two-tailed P-value is less than 0.05.
 

14
 
The incidence of neoplastic or nonneoplastic lesions has been
 

given as the ratio of the number of animals bearing such lesions at a
 

specific anatomic site (numerator) to the number of animals in which
 

that site was examined (denominator). In most instances, the denominators included only those animals for which that site was examined
 

histologically. However, when macroscopic examination was required
 

to detect lesions prior to histologic sampling (e.g., skin or mammary
 

tumors), or when lesions could have appeared at multiple sites (e.g.,
 

lymphomas), the denominators consist of the numbers of animals necropsied.
 

The purpose of the statistical analyses of tumor incidence is to
 

determine whether animals receiving the test chemical developed a significantly higher proportion of tumors than did the control animals.
 

As a part of these analyses, the one-tailed Fisher exact test (Cox,
 

1970, pp. 48-52) was used to compare the tumor incidence of a control
 

group to that of a group of treated animals at each dose level. When
 

results for a number of treated groups, k, are compared simultaneously
 

with those for a control group, a correction to ensure an overall
 

significance level of 0.05 may be made. The Bonferroni inequality
 

(Miller, 1966, pp. 6-10) requires that the P-value for any comparison
 

be less than or equal to 0.05/k. In cases where this correction was
 

used, it is discussed in the narrative section. It is not, however,
 

presented in the tables, where the Fisher exact P-values are shown.
 

15
 
The Cochran-Armitage test for linear trend in proportions, with
 

continuity correction (Armitage, 1971, pp. 362-365), was also used
 

when appropriate. Under the assumption of a linear trend, this test
 

determined if the slope of the dose-response curve is different from
 

zero at the one-tailed 0.05 level of significance. Unless otherwise
 

noted, the direction of the significant trend was a positive dose relationship. This method also provides a two-tailed test of departure
 

from linear trend.
 

A time-adjusted analysis was applied when numerous early deaths
 

resulted from causes that were not associated with the formation of
 

tumors. In this analysis, deaths that occurred before the first
 

tumor was observed were excluded by basing the statistical tests on
 

animals that survived at least 52 weeks, unless a tumor was found at
 

the anatomic site of interest before week 52. When such an early
 

tumor was found, comparisons were based exclusively on animals that
 

survived at least as long as the animal in which the first tumor was
 

found. Once this reduced set of data was obtained, the standard procedures for analyses of the incidence of tumors (Fisher exact tests,
 

Cochran-Armitage tests, etc.) were followed.
 

When appropriate, life-table methods were used to analyze the
 

incidence of tumors. Curves of the proportions surviving without an
 

observed tumor were computed as in Saffiotti et al. (1972). The week
 

during which animals died naturally or were sacrificed was entered as
 

the time point of tumor observation. Cox's methods of comparing
 

16
 
these curves were used for two groups; Tarone's extension to testing
 

for linear trend was used for three groups. The statistical tests for
 

the incidence of tumors which used life-table methods were one-tailed
 

and, unless otherwise noted, in the direction of a positive dose
 

relationship. Significant departures from linearity (P < 0.05, two-


tailed test) were also noted.
 

The approximate 95 percent confidence interval for the relar:"e
 

risk of each dosed group compared to its control was calculated from
 

the exact interval on the odds ratio (Gart, 1971). The relative risk
 

is defined as p /p where p is the true binomial probability of the
 

t c t
 

incidence of a specific type of tumor in a treated group of aninuuo
 

and p is the true probability of the spontaneous incidence of the
 

c
 

same type of tumor in a control group. The hypothesis of eq»ality
 

between the true proportion of a specific tumor in a treated group
 

and the proportion in a control group corresponds to a relative risk
 

of unity. Values in excess of unity represent the condition of a
 

larger proportion in the treated group than in the control.,
 

The lower and upper limits of the confidence interval of the
 

relative risk have been included in the tables of statistical analyses. The interpretation of the limits is that in approximately 95
 

percent of a large number of identical experiments, the true ratio
 

of the risk in a treated group of animals to that in a control group
 

would be within the interval calculated from the experiment. When
 

the lower limit of the confidence interval is greater than one, it
 

17
 
can be inferred that a statistically significant result (a P < 0.025
 

one-tailed test when the control incidence is not zero, P < 0.050
 

when the control incidence is zero) has occurred. When the lower
 

limit is less than unity but the upper limit is greater than unity,
 

the lower limit indicates the absence of a significant result while
 

the upper limit indicates that there is a theoretical possibility
 

of the induction of tumors by the test chemical which could not be
 

detected under the conditions of this test.
 

18
 
III. CHRONIC TESTING RESULTS: RATS
 

A. Body Weights and Clinical Observations
 

No evidence of mean body weight depression, in relation to controls, was apparent in dosed male rats. The mean body weight of high
 

dose female rats was depressed relative to the control group (Figure 2),
 

No abnormal clinical signs were recorded.
 

B. Survival
 

The estimated probabilities of survival for male and female rats
 

in the control and trimethylthiourea-dosed groups are shown in Figure
 

3. For both males and females, the Tarone test did not indicate a
 

significant positive association between dosage and mortality.
 

There were adequate numbers of male rats at risk from late-


developing tumors, as 46/50 (92 percent) of the high dose, 45/50 (90
 

percent) of the low dose and 18/20 (90 percent) of the control group
 

survived on test for at least 100 weeks.
 

For females, with 32/50 (64 percent) of the high dose, 38/50 (76
 

percent) of the low dose, and 17/20 (85 percent) of the control group
 

alive on test until the termination of the study, there were adequate
 

numbers at risk from late-developing tumors.
 

C. Pathology
 

Histopathologic findings on neoplasms in rats are summarized in
 

Appendix A (Tables Al and A2); findings on nonneoplastic lesions are
 

summarized in Appendix C (Tables Cl and C2).
 

19
 
750- -750 

600­ -600 

H- 440 — X -450 

cr 

h-300 

LU 

5 

150­ -150 

MALE RX 

15 30 

I ' I \ I 

45 60 ' 75 

TIME ON TEST (WEEKS) 

90 105 120 

750­ •750 

CO s 

< 

DC 

45< I 

O 

- 600 

-450 

§300-

CO 

-300 

150­ -150 

FEMALE RATS 

~l

15 

r 

30 45 60 75 

TIME ON TEST (WEEKS) 

90 105 120 

FIGURE 2 

GROWTH CURVES FOR TRIMETHYLTHIOUREA CHRONIC STUDY RATS 

20 
PROBABILITY OF SURVIVAL 

p p o b

 a> CO 

I 

C/l 

c 

30 

m 

3D 

O 

O 

8­

pa 

8 

r! 5­ s 

m 

O 

m I g en 

O 

33 

m 

> 

O 

•33 

O 

O 8­

o 

30 5 8 

a­ § 

PROBABILITY OF SURV

o p o 

o fen 

I I I I 

8­

d fta­ 5 

m 

m 

s­

\ I 

p o p o

 a> 
A variety of neoplasms was observed in both the dosed and control groups. Each of these types has been encountered previously as
 

a spontaneous lesion in this strain of rat.
 

The lesions of interest observed at necropsy were those associated
 

with the thyroid, particularly in the dosed females. The incidences
 

of follicular and C-cell adenomas and carcinomas of the thyroid gland
 

were observed to be higher in the dosed animals than in the controls.
 

The tumors were most common in the high dose females as shown in the
 

following table:
 

Low High
 

Control Dose Dose
 

Males
 

Number of Animals with Thyroid
 

Examined Histopathologically (17) (37) (39)
 

Follicular-Cell Adenoma 0 0 0
 

Follicular-Cell Carcinoma 0 1(3%) 3(8%)
 

C-Cell Adenoma 2(12%) 1(3%) 0
 

C-Cell Carcinoma 0 0 2(5%)
 

Females
 

Number of Animals with Thyroid
 

Examined Histopathologically (17) (38) (47)
 

Follicular-Cell Adenoma 0 0 9(19%)
 

Follicular-Cell Carcinoma 0 1(3%) 14(30%)
 

C-Cell Adenoma 1(6%) 2(5%) 2(4%)
 

C-Cell Carcinoma 0 1(3%) 2(4%)
 

Adenomas were recognized as well-defined nodules of either parafollicular or follicular cells. Many of the latter had papillary or
 

22
 
cystic features as well. Features distinguishing carcinomas from
 

adenomas include capsular invasion, increased mitotic activity, hyperchromatism, loss of cell polarity to basement membranes, piling up
 

of cells, and, in the follicular-cell carcinomas, a tendency toward
 

medullary rather than acinar proliferation. Metastases were observed
 

in only one rat; however, local invasion from thyroid neoplasms did
 

occur.
 

The usual variety of nonneoplastic lesions was present in both
 

dosed and control animals. Such lesions have been encountered previously in the Fischer 344 rat and are considered to be spontaneous.
 

Mortality toward the end of the study exceeded 10 percent in all
 

groups. Most deaths were due to neoplasia complicated by chronic
 

murine pneumonia.
 

The results of this pathologic examination indicated that trimethylthiourea was carcinogenic in female Fischer 344 rats at the doses
 

given, inducing neoplasms of the thyroid.
 

D. Statistical Analyses of Results
 

The results of the statistical analyses of tumor incidence in
 

rats are summarized in Tables 3 and 4. The analysis is included for
 

every type of malignant tumor in either sex where at least two such tumors were observed in at least one of the control or trimethylthioureadosed groups and where such tumors were observed in at least 5 percent
 

of the group.
 

23
 
___ 

_ __ 

___ _ _ _ 

TABLE 3
 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS AT
 

a
 SPECIFIC SITES IN MALE RAT TREATED WITH TRIMETHYLTHIOUREA


HIGH
 

DOSE
 

5/50(0.10)
 

N.S.
 

1.000
 

0.184
 

10.007
 

101
 

3/39(0.08)
 

N.S.
 

Infinite
 

0.276
 

Infinite
 

2/39(0.05)
 

N.S.
 

Infinite
 

0.135
 

Infinite
 

TOPOGRAPHY : MORPHOLOGY
 

Hematopoietic System: Leukemia or
 

Malignant Lymphoma'3
 

P Values0
 

Relative Risk (Control)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

10

 b
 ** Thyroid: Follicular-Cell Carcinoma
 

P Values0
 

Relative Risk (Control)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Thyroid: C-Cell Carcinoma
 

P Values0
 

Relative Risk (Control)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

CONTROL
 

2/20(0.10)
 

N.S.
 

94
 

0/17(0.00)
 

N.S.
 

0/17(0.00)
 

N.S.
 

LOW
 

DOSE
 

4/50(0.08)
 

N.S.
 

0.800
 

0.128
 

8.436
 

68
 

1/37(0.03)
 

N.S.
 

Infinite
 

0.026
 

Infinite
 

106
 

0/37(0.00)
 

N.S.
 

93 

106 
TABLE 3 (CONCLUDED)
 

LOW HIGH 

TOPOGRAPHY : MORPHOLOGY CONTROL DOSE DOSE 

Thyroid: C-Cell Carcinoma or C-Cell 

Adenoma*3 2/17(0.12) 1/37(0.03) 2/39(0.05) 

P Values N.S. N.S. N.S. ___ Relative Risk (Control) 0.230 0.436 

Lower Limit 0.004 0.035 

Upper Limit 4.175 5.686 

Weeks to First Observed Tumor 106 106 106 

Testis: Interstitial-Cell Tumor 18/20(0.90) 42/50(0.84) 45/49(0.92) 

P Values0 N.S. N.S. N.S. ___ 

Relative Risk (Control) 0.933 1.020 

Lower Limit 0.816 0.895 

Upper Limit 1.226 1.256 

Weeks to First Observed Tumor 100 94 93 

a

Treated groups received doses of 250 or 500 ppm in feed.
 

Number of tumor-bearing animals/number of animals examined at site (proportion).
 

The probability level for the Cochran-Armitage test is given beneath the incidence of tumors in
 

the control group when P < 0.05; otherwise, not significant (N.S.) is indicated. The probability
 

level for the Fisher exact test for the comparison of a treated group with the control group is
 

given beneath the incidence of tumors in the treated group when P < 0.05; otherwise, not signifi­ cant (N.S.) is indicated. For both Cochran-Armitage and Fisher exact tests a negative designation (N) indicates a lower incidence in the treated group(s) than in the control group.
 

The 95% confidence interval on the relative risk of the treated group to the control group.
 
_ __ 

TABLE 4
 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS AT
 

SPECIFIC SITES IN FEMALE RATS TREATED WITH TRIMETHYLTHIOUREA2
 

TOPOGRAPHY: MORPHOLOGY
 

Hematopoietic System: Leukemia or
 

Malignant Lymphomab
 

P Values0
 

Relative Risk (Control)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

to
 Liver: Hepatocellular Carcinoma or
 

Neoplastic Nodule^
 

P Values0
 

Relative Risk (Control)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Pituitary: Chromophobe Adenoma
 

P Values0
 

Relative Risk (Control)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

CONTROL
 

0/20(0.00)
 

N.S.
 

2/20(0.10)
 

P = 0.04KN)
 

106
 

2/18(0.11)
 

N.S.
 

95
 

LOW
 

DOSE
 

1/50(0.02)
 

N.S.
 

Infinite
 

0.022
 

Infinite
 

102
 

2/49(0.04)
 

N.S.
 

0.408
 

0.032
 

5.381
 

93
 

8/44(0.18)
 

N.S.
 

1.636
 

0.378
 

14.919
 

93
 

HIGH
 

DOSE
 

3/50(0.06)
 

N.S.
 

Infinite
 

0.250
 

Infinite
 

100
 

0/49(0.00)
 

N.S.
 

0.000
 

0.000
 

1.372
 

11/47(0.23)
 

N.S.
 

2.106
 

0.535
 

18.439
 

84 
___ 

___ 

_ __ 

TOPOGRAPHY: MORPHOLOGY
 

Thyroid: Follicular-Cell Carcinoma
 

P Values0
 

Relative Risk (Control)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Thyroid: Follicular-Cell Carcinoma or
 

Follicular-Cell Adenomab
 

P Values0
 

Departure from Linear Trend
 

Relative Risk (Control)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Thyroid: C-Cell Carcinoma or C-Cell
 

Adenoma"3
 

P Values0
 

Relative Risk (Control)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

TABLE 4 (CONTINUED)
 

CONTROL
 

0/17(0.00)
 

P < 0.001
 

0/17(0.00)
 

P < 0.001
 

P = 0.015
 

1/17(0.06)
 

N.S.
 

95
 

LOW
 

DOSE
 

1/38(0.03)
 

N.S.
 

Infinite
 

0.025
 

Infinite
 

106
 

1/38(0.03)
 

N.S.
 

Infinite
 

0.025
 

Infinite
 

106
 

3/38(0.08)
 

N.S.
 

1.342
 

0.120
 

68.559
 

99
 

HIGH
 

DOSE
 

14/47(0.30)
 

P = 0.007
 

Infinite
 

1.667
 

Infinite
 

68
 

23/47(0.49)
 

P < 0.001
 

Infinite
 

2.873
 

Infinite
 

68
 

4/47(0.09)
 

N.S.
 

1.447
 

0.161
 

69.681
 

84 
00 

TABLE

TOPOGRAPHY: MORPHOLOGY
 

Mammary Gland: Fibroadenoma
 

P Values0
 

Relative Risk (Control)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Mammary Gland: Adenocarcinoma NOS or
 

Papillary Adenocarcinoma
 

P Values0
 

Relative Risk (Control)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Mammary Gland: Fibroadenoma, Adenocarcinoma NOS, or Papillary Adenocarcinoma
 

P Values0
 

Relative Risk (Control)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

4 (CONTINUED) 

CONTROL
 

1/20(0.05)
 

N.S.
 

88
 

2/20(0.10)
 

P = 0.035(N)
 

95
 

3/20(0.15)
 

N.S.
 

88
 

LOW
 

DOSE
 

3/50(0.06)
 

N.S.
 

1.200
 

0.106
 

61.724
 

106
 

1/50(0.02)
 

N.S.
 

0.200
 

0.004
 

3.681
 

88
 

4/50(0.08)
 

N.S.
 

0.533
 

0.102
 

3.410
 

88
 

HIGH
 

DOSE
 

6/50(0.12)
 

N.S.
 

2.400
 

0.325
 

108.021
 

95
 

0/50(0.00)
 

N.S.
 

0.000
 

0.000
 

1.345
 

6/50(0.12)
 

N.S.
 

0.800
 

0.195
 

4.615
 

95
 
TABLE 4 (CONCLUDED)
 

LOW HIGH
 

TOPOGRAPHY: MORPHOLOGY CONTROL DOSE DOSE
 

Uterus: Endometrial Stromal Polyp 2/20(0.10) 0/50(0.00) 0/49(0.00)
 

P Values0 P = 0.025(N) N.S. N.S.
 

Departure from Linear Trend P = 0.043
 

Relative Risk (Control) 0.000 0.000 

Lower Limit 0.000 0.000

 

Upper Limit 1.345 1.372 

Weeks to First Observed Tumor 106 

Treated groups received doses of 250 or 500 ppm in feed.
 

N> Number of tumor-bearing animals/number of animals examined at site (proportion) .
 

The probability level for the Cochran-Armitage test is given beneath the incidence of tumors in
 

the control group when P < 0.05; otherwise, not significant (N.S.) is indicated. The probability
 

level for the Fisher exact test for the comparison of a treated group with the control group is
 

given beneath the incidence of tumors in the treated group when P < 0.05; otherwise, not significant (N.S.) is indicated. For both Cochran-Armitage and Fisher exact tests a negative designation (N) indicates a lower incidence in the treated group(s) than in the control group.
 

The 95% confidence interval on the relative risk of the treated group to the control group.
 £
 

The probability level of the test for departure from linear trend is given beneath the control
 

group when P < 0.05.
 
For females, the Cochran-Armitage test indicated a significant
 

(P < 0.001) positive association between dose and the incidence of
 

follicular-cell carcinomas of the thyroid. The Fisher exact test
 

comparing high dose to control was also significant (P = 0.007).
 

Furthermore, the combined incidences of follicular-cell carcinomas
 

or follicular-cell adenomas of the thyroid also were significant for
 

both the Cochran-Armitage test (P < 0.001) and the high dose Fisher
 

exact test (P < 0.001). Based upon these statistical results, the
 

administration of trimethylthiourea was associated with the increased
 

incidence of follicular-cell carcinomas of the thyroid in female
 

Fischer 344 rats.
 

None of the statistical tests for any site in male rats indicated
 

a significant positive association between chemical administration and
 

tumor incidence.
 

In female rats, the Cochran-Armitage test indicated significant
 

negative associations between dosage and the combined incidence of
 

hepatocellular carcinomas or neoplastic nodules, between dosage and
 

mammary gland adenocarcinomas, and between dosage and the incidence
 

of endometrial stromal polyps. In all cases, however, the Fisher
 

exact tests comparing high dose to control and low dose to control
 

were not significant.
 

30
 
IV. CHRONIC TESTING RESULTS: MICE
 

A. Body Weights and Clinical Observations
 

Both high and low dose male and female mice had severe mean body
 

weight depression relative to the control group. Distinct dose-related
 

mean body weight depression was observed in female mice after week 25
 

(Figure 4).
 

No abnormal clinical signs were recorded.
 

B. Survival
 

The estimated probabilities of survival for male and female mice
 

in the control and trimethylthiourea-dosed groups are shown in Figure
 

5. For both male and female mice the Tarone test did not indicate a
 

significant positive association between dosage and mortality.
 

There were adequate numbers of male mice at risk from late-


developing tumors as 50/50 (100 percent) of the high dose, 44/50 (88
 

percent) of the low dose, and 18/20 (90 percent) of the control group
 

survived on test until the termination of the study. Only one natural
 

death, in the control group at week 62, was reported among all dosed
 

and control male mice.
 

For females, with 43/50 (86 percent) of the high dose, 43/50 (86
 

percent) of the low dose, and 15/20 (75 percent) of the control group
 

surviving on test until termination of the study, there were adequate
 

numbers at risk from late-developing tumors. Two high dose females
 

were missing starting in week 87, 4 low dose females were missing
 

starting in weeks 23, 58, and 68, and one control female was missing
 

starting in week 30.
 
50- -50 

40 — -40 

t/3 

-30 

> 20­

Q 

O 

-20 

CD 

< CONTROL 

LU 

ID­ LOW DOSE -10 

MALE MICE HIGH DOSE 

I I I T

 I ' I I I 

15 30 45 60 75 90 105 120 

TIME ON TEST (WEEKS) 

50­ -50 

40­ -40 

230- -30 

£20-

o 

oa 

10— 

FEMALE MICE 

_

...

._

 CONTROL 

 LOW DOSE 

 HIGH DOSE 

-20 

—10 

I ' I I I I T I 

15 30 45 60 75 90 105 120 

TIME ON TEST (WEEKS) 

FIGURE 4 

GROWTH CURVES FOR TRIMETHYLTHIOUREA CHRONIC STUDY MICE 

32 

i 
- -

PROBABILITY OF SURVIVAL PROBABILITY OF SURV

c3 0 p O O .k c3 0 0 o 

'<:3 Kj -^ O) 00 CD ci Kj * b) 

i i 1 i 1 > 1 I 1 i 1 1 1 

o — J o — 

•n r m CO £ 1 S 

r­ 30 <?~ CP 

i- 1 m m ^^ < _ 0 

m I- O 

m 

82 8- 1 c ~" -o 

3D 

1 

^ H *. d ft­ ?

^

 i Tl

m —1 m 

3D O J O 

z 22 * 

m ^p"c ^

K

- yj o _ {/) OJ 

•* m — s 

T W m rn "^ m rn 5 /^ w c J2 I3D ^ • -^j _ m en U1 

I r' t 

­ 3

0

D 

i pj 1 :

1 §- i \ ir o "~ i \

• ^ i

i 3 

C r O I r o o 

z -< 

11 H 

2 X 

o o ° — 1 i1 Ss r~ 

w

m s- S s ° 

§- i i | i | i | SJ i i i i i i 

C3 O O p O <= 0 o o 

(3 io A o> bo O <3 Ko '.t* b) 
C. Pathology
 

Histopathologic findings on neoplasms in mice are summarized in
 

Appendix B (Tables Bl and B2); findings on nonneoplastic lesions are
 

summarized in Appendix D (Tables Dl and D2).
 

A variety of neoplastic and nonneoplastic lesions occurred in
 

both dosed and control animals. The type, incidence, and distribution of these lesions were similar to those expected in aged B6C3F1
 

mice; therefore, these lesions were considered to be spontaneous and
 

not related to compound administration.
 

The results of this pathologic examination indicated that trimethylthiourea was not carcinogenic in B6C3F1 mice under the conditions
 

of this study.
 

D. Statistical Analyses of Results
 

For male mice the results of the statistical analyses are included in Table 5 for every type of malignant tumor where at least
 

two such tumors were observed in at least one of the control or
 

trimethylthiourea-dosed groups and where such tumors were observed
 

in at least 5 percent of the group. There were no sites in female
 

mice where the above criteria were met.
 

None of the statistical tests for any site in mice of either sex
 

indicated a significant positive association between chemical administration and tumor incidence. Based upon these statistical results
 

there was no evidence that trimethylthiourea was a carcinogen in
 

B6C3F1 mice under the conditions of this bioassay.
 

34
 
___ 

TABLE 5
 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS AT
 

SPECIFIC SITES IN MALE MICE TREATED WITH TRIMETHYLTHIOUREA*
 

LOW
 

TOPOGRAPHY: MORPHOLOGY CONTROL DOSE
 

Lung: Alveolar /Bronchiolar Carcinoma
 

or Alveolar/Bronchiolar Adenoma" 1/18(0.06) 5/44(0.11)
 

P Values0 N.S. N.S.
 

Relative Risk (Control) 2.045
 

Lower Limit 0.258
 

Upper Limit 94.395
 

Weeks to First Observed Tumor 91 91
 

Liver: Hepatocellular Adenoma or
 

Neoplastic Nodule^ 6/19(0.32) 2/44(0.05) 

P Values0 P = 0.003(N) P = 0.007(N) p

Departure from Linear Trend 

d 

Relative Risk (Control) 

P = 0.020 

0.144 

Lower Limit 0.016 

Upper Limit 0.729 

Weeks to First Observed Tumor 91 91 

HIGH
 

DOSE
 

8/50(0.16)
 

N.S.
 

2.880
 

0.439
 

124.908
 

91
 

2/50(0.04)
 

P = 0.004(N)
 

0.127
 

0.014
 

0.645
 

91
 
TABLE 5 (CONCLUDED) 

Q
 

Treated groups received doses of 500 or 1000 ppm in feed.
 

Number of tumor-bearing animals/number of animals examined at site (proportion).
 

c

The probability level for the Cochran-Armitage test is given beneath the incidence of tumors in
 

the control group when P < 0.05; otherwise, not significant (N.S.) is indicated. The probability
 

level for the Fisher exact test for the comparison of a treated group with the control group is
 

given beneath the incidence of tumors in the treated group when P < 0.05; otherwise, not significant (N.S.) is indicated. For both Cochran-Armitage and Fisher exact tests a negative designation (N) indicates a lower incidence in the treated group(s) than in the control group.
 

The 95% confidence interval on the relative risk of the treated group to the control group.
 0
 

The probability level of the test for departure from linear trend is given beneath the control
 

group when P < 0.05,
 
In male mice the Cochran-Armitage test and the Fisher exact
 

tests comparing high dose to control and low dose to control indicated a significant negative association between dose and the combined incidence of hepatocellular adenomas or neoplastic nodules
 

of the liver. However, historical control data from the same
 

laboratory indicate an incidence of 32/272 (12 percent) of these
 

tumors in untreated male B6C3F1 mice as compared with the higher
 

6/19 (32 percent) incidence in control males in this bioassay.
 

To provide additional insight into the possible carcinogenicity
 

of this compound, 95 percent confidence intervals on the relative
 

risk have been estimated and entered in Table 5 based upon the
 

observed tumor incidence rates. In many of the intervals shown in
 

Table 5, the value one is included; this indicates the absence of
 

statistically significant results. It should also be noted that
 

many of the confidence intervals have an upper limit greater than
 

one, indicating the theoretical possibility of tumor induction in
 

mice by trimethylthiourea that could not be established under the
 

conditions of this test.
 

37
 
V. DISCUSSION
 

There were no significant positive associations between the dosage of trimethylthiourea administered and mortality in rats or mice
 

of either sex. Adequate numbers of animals in all groups survived
 

sufficiently long to be at risk from late-developing tumors. For high
 

dose female rats and for dosed mice of both sexes compound-related
 

mean body weight depression was observed, indicating that the dosages
 

of trimethylthiourea administered to these animals may have approximated the maximum tolerated dosages. Since no mean body weight
 

depression relative to controls, no significant accelerated mortality,
 

and no other signs of toxicity were associated with administration of
 

trimethylthiourea to male rats, it is possible that these animals may
 

have been able to tolerate a higher dietary concentration.
 

For female rats, there was a significant positive association
 

between dosage and the incidences of follicular-cell carcinomas
 

(i.e., 0/17, 1/38 [3 percent], and 14/47 [30 percent] in the control,
 

low dose, and high dose groups, respectively). The high dose to control Fisher exact comparison was also significant for this neoplasm
 

in female rats. In addition, when female rats having follicular-cell
 

carcinomas and follicular-cell adenomas were combined and the resulting tumor incidences analyzed statistically, the Cochran-Armitage
 

test and the high dose to control Fisher exact comparison were, once
 

again, significant.
 

38
 
There were no significant positive associations between compound
 

administration and tumor incidence in male rats or in mice of either
 

sex.
 

Under the conditions of this bioassay, dietary administration
 

of trimethylthiourea was carcinogenic to female Fischer 344 rats,
 

inducing follicular-cell carcinomas of the thyroid. There was not
 

sufficient evidence for the carcinogenicity of the compound in male
 

Fischer 344 rats or in B6C3F1 mice of either sex.
 

39
 
VI. BIBLIOGRAPHY
 

Arnitage, P., Statistical Methods in Medical Research, Chapter 14.
 

J. Wiley & Sons, New York, 1971.
 

Berenblum, I., editor, Carcinogenicity Testing. International Union
 

Against Cancer, Technical Report Series, Vol. 2. International
 

Union Against Cancer, Geneva, 1969.
 

Chemical Abstracts Service, The Chemical Abstracts Service (CAS)
 

Ninth Collective Index, Volumes 76-85, 1972-1976. American
 

Chemical Society, Washington, B.C., 1977.
 

Cox, D.R., Analysis of Binary Data, Chapters 4 and 5. Methuen and
 

Co., Ltd., London, 1970.
 

Cox, D.R., "Regression Models and Life-Tables." Journal of the Royal
 

Statistical Society, Series "B" 34:187-220, 1972.
 

Gait, J.J., "The Comparison of Proportions: A Review of Significance
 

Tests, Confidence Limits, and Adjustments for Stratification."
 

International Statistical Institute Review 39:148-169, 1971.
 

Hauser, M. and B.M. Malofsky, "Surface Activator for Anaerobic Adhesives." Ger. Offen. 2,401,744 (Loctite Corp.), August 1, 1974;
 

Chemical Abstracts 82, 17949g.
 

Inuzuka, Y., N. Kameyama, and K. Watanabe, "Phthalocyanine Pigments."
 

Japan. Kokai 76 26,933 (Toyo Ink Mfg. Co., Ltd.), March 5, 1976;
 

Chemical Abstracts 85, 7367p.
 

Kaplan, E.L., and P. Meier, "Nonparametric Estimation from Incomplete
 

Observations." Journal of the American Statistical Association
 

53_:457-481, 1958.
 

Kirkpatrick, G., "Degradable Polyethylene Films." Ger. Offen.
 

2,261,778 (Union Carbide Corp.), July 19, 1973; Chemical Abstracts 79, 147239z.
 

Langlade, A., "Extrusion and Continuous Vulcanization of Polychloropropene Rubbers." Rule Mex. Plast. ^2_(364): 18-20, 22-24, 1976;
 

Chemical Abstracts 85, 161530t.
 

Linhart, M.S., J.A. Cooper, R.L. Martin, N.P. Page, and J.A. Peters,
 

"Carcinogenesis Bioassay Data System." Computers and Biomedical
 

Research 7:230-248, 1974.
 

40
 
Lofquist, R.A. and P.R. Saunders, "Water-Soluble Thioureas to Inhibit
 

Ozone Fading of Dyed Polyamides." U.S. Patent 3,822,996 (Allied
 

Chemical Corp.), July 9, 1974; Chemical Abstracts 83, 61478x.
 

Miller, R.G., Simultaneous Statistical Inference. McGraw-Hill Book
 

Co., New York, 1966.
 

Ohashi, K., S. Kusayama, and W. Ota, "Adhesives." Ger. Offen.
 

2,106,155 (Sumitomo Chemical Co., Ltd.), August 19, 1971; Chemical Abstracts 76, 4623x.
 

Palmer, L.B. and R.P. Conger, "Carpet Embossing in Register With
 

Print." U.S. Patent 3,849,159 (Congoleum Industries, Inc.),
 

November 19, 1974; Chemical Abstracts 82, 99931g.
 

Radomski, J.L., W.B. Deichmann, W.E. MacDonald, and E.M. Glass, "Synergism Among Oral Carcinogens. I. Results of the Simultaneous
 

Feeding of Four Tumorigens to Rats." Toxicology and Applied
 

Pharmacology 7:652-656, 1965.
 

Rosati, R.L., "Substituted Acyl Derivatives of Q'-Aminopenicillins."
 

Ger. Offen. 2,316,170 (Pfizer, Inc.), December 6, 1973; Chemical
 

Abstracts 80, 82954c.
 

Saffiotti, U., R. Montesano, A.R. Sellakumar, F. Cefis, and D.G.
 

Kaufman, "Respiratory Tract Carcinogenesis in Hamsters Induced
 

by Different Numbers of Administration of Benzo (a) Pyrene and
 

Ferric Oxide." Cancer Research 32:1073-1079, 1972.
 

Stanford Research Institute, 1977 Directory of Chemical Producers,
 

U.S.A. Menlo Park, California, 1977.
 

Starmer, P.H., "Vulcanizable Compositions Containing Diene/Nitrile
 

Polymers Having Active Halogen Sites." U.S. Patent 3,976,625
 

(B. F. Goodrich Co.), August 24, 1976; Chemical Abstracts 85,
 

161608z.
 

Starmer, P.H., "Vulcanizable Mixtures." Ger. Offen. 2,557,559 (B. F.
 

Goodrich Co.), July 16, 1976; Chemical Abstracts 85, 125521g.
 

Tarone, R.E., "Tests for Trend in Life-Table Analysis." Biometrika
 

j>2_:679-682, 1975.
 

Vandenberg, E.J. and W.D. Willis, "Treatment of Keratinous Fibers."
 

British Patent 1,349,306 (Hercules, Inc.), April 3, 1974; Chemical Abstracts 81, 51035v.
 

41
 

Review of the Bioassay of Trimethylthiourea* for Carcinogenicity
 

by the Data Evaluation/Risk Assessment Subgroup of the
 

Clearinghouse on Environmental Carcinogens
 

August 31, 1978
 

The Clearinghouse on Environmental Carcinogens was established
 

in May, 1976, in compliance with DHEW Committee Regulations and the
 

Provisions of the Federal Advisory Committee Act. The purpose of the
 

Clearinghouse is to advise the Director of the National Cancer Institute
 

(NCI) on its bioassay program to identify and to evaluate chemical
 

carcinogens in the environment to which humans may be exposed. The
 

members of the Clearinghouse have been drawn from academia, industry,
 

organized labor, public interest groups, State health officials, and
 

quasi-public health and research organizations. Members have been
 

selected on the basis of their experience in carcinogenesis or related
 

fields and, collectively, provide expertise in chemistry, biochemistry,
 

biostatistics, toxicology, pathology, and epidemiology. Representatives
 

of various Governmental agencies participate as ad hoc members. The
 

Data Evaluation/Risk Assessment Subgroup of the Clearinghouse is
 

charged with the responsibility of providing a peer review of reports
 

prepared on NCI-sponsored bioassays of chemicals studied for carcinogenicity. It is in this context that the below critique is given on
 

the bioassay of Trimethylthiourea for carcinogenicity.
 

The primary reviewer noted that Trimethylthiourea induced an increased
 

incidence of thyroid follicular-cell neoplasms in only treated female,
 

rats. Significant ^increases in tumor incidences were not found in other
 

treatment groups. After a brief description of the experimental design,
 

the primary reviewer commented on the fact that not all of the thyroid
 

glands were examined. She suggested that this may have caused a bias in
 

the results. Despite the experimental shortomcings, the primary reviewer
 

concurred with the conclusion in the report that Trimethylthiourea was
 

carcinogenic in female rats. She added that the data were insufficient,
 

however, to base an estimate of the human risk posed by Trimethylthiourea.
 

A motion was approved unanimously that the report on the bioassay
 

of Trimethylthiourea be accepted as written.
 

Members present were:
 

Arnold L. Brown (Chairman), University of Wisconsin Medical School
 

Joseph Highland, Environmental Defense Fund
 

Michael Shimkin, University of California at San Diego
 

Louise Strong, University of Texas Health Sciences Center
 

43
 
Members present were:
 

Arnold L. Brown (Chairman), University of Wisconsin School of Medicine
 

Joseph Highland, Environmental Defense Fund
 

Michael Shimkin, University of California at San Diego
 

Louise Strong, University of Texas Health Sciences Center
 

Subsequent to this review, changes may have been made in the
 

bioassay report either as a result of the review or other reasons.
 

Thus, certain comments and criticisms reflected in the review may
 

no longer be appropriate.
 

44
 

APPENDIX A
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS
 

IN RATS TREATED WITH TRIMETHYLTHIOUREA
 

TABLE Al

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN MALE RATS TREATED WITH TRIMETHYLTHIOUREA 

CONTROL(UNTR) LOW DOSE

11-10*5 11-1043

 HIGH DOSE 

 11-10*1 

ANIHALS INITIALLY IN STUDY 20

ANIMALS NECROPSIED 20

ANIMALS EXAMINED HISTOPATHOLOGICALL^* 20

 50

 50

 50

 50 

 50 

 49 

INTEGUHENTAPY SYSTEM
 

*SKIN (20) (50) (50)
 

PAPILLOHA, NOS 1 (5X) 1 (2t)
 

SQUAHOUS CELL CARCINOMA 1 (5X)
 

FIBROMA 1 (2%)
 

NEURILERCHA 1 (5X)
 

RESPIRATORY SYSTEM
 

f TRACHEA (19) (50) (09) 

FOLLICOLAR-CELL CARCINOMA, HETAS 1 (2t) 

*LUNG (20) (45) (49) 

ALVEOLAR/BRONCHIOLAR ADENOHA 1 (5X) 1 (2X) 1 (2X) 

FOLLICULAR-CELL CARCINOHA, BETAS 1 (2() 

SARCOHA, NOS, HETASTATIC 1 (2<) 

FIBROSARCOHA, HETASTATIC 1 (2X) 

HEMATOPOIETIC SYSTEH 

*MULTIPLE ORGANS (20) (50) (50) 

MALIGNANT LYHPHOMA, NOS 2 (10*) 3 (6X) 2 (4X) 

LEUKEMIA,NOS 1 (2X) 2 (4X) 

tSPLBEN (20) (50) (49)
 

MALIGNANT LYMPHOMA, NOS 1 (2X)
 

CIRCULATORY SYSTEH
 

NOfiE
 

* NUMBER OF ANIHALS WITH TISSUE EXAMINED MICROSCOPICALLY 

* NUMBER OF ANIMALS N8CROPSIED 

**EXCLUDES PAKIIALLT AUTOLYZED ANIMALS. 

A-3 
TABLE Al (CONTINUED) 

" CONTROL (UNTR) LOS DOSE 

11-1045 11-1043 

DIGESTIVE SYSTEM 

*LIVEB (20) (49) 

NEOPLASTIC NODDLE 1 (5*)

 

(ESOPHAGUS (19) (50) 

FOLLICULAB-CELL CABCINOMA, BETAS 

tCECUM (20) (49) 

PAPILLARY ADENOMA 1 (2*) 

UBINARY SYSTEM 

NONE 

INDOCBINE SYSTIM 

tPITDlTARY (17) (45) 

CHROMOPHOBE ADENOMA 1 (6*) 1 (2X) 

1 ADRENAL (20) (50) 

PHEOCHBOHOCYTOMA 1 (5*) 2 (4*) 

MHYROID (17) (37) 

FOLLICDLAR-CELL CABCINOMA 1 (3*) 

C-CELL ADENOMA 2 (12*) 1 (3*) 

C-CELL CARCINOMA 

tPAHCBEATIC 1SLZTS (20) (49)

ISLET-CELL ADENOHA 2 (4<) 

REPRODUCTIVE SYSTEM 

fTBSTIS (20) (50) 

INTERSTITIAL-CELL TUMOR 18 (90*) 42 (84X) 

»EB»OUS SYSTEM 

NONE 

t NUMBER OF ANIMALS BITH TISSUE EXAMINED MICROSCOPICALLY 

* NOMBEB OF ANIMALS NECROPSIED 

HIGH DOSE 

11-1041 

<t9) 

1 (2*) 

(49) 

1 (2X) 

(49) 

(36) 

1 (3X) 

(49) 

2 (4X) 

(39) 

3 (8*) 

2 (5X) 

(49) 

(49) 

45 (92*) 

A-4 
TABLE Al (CONTINUED) 

CONTROL(UHTR) L0» DOSE HIGH DOSE 

11-10U5 11-10*3 11-10U1 

SPECIAL SENSE ORGANS 

• EXTERNAL EAP (20) (50) (50) 

FIBPOSARCOMA 1 (2«) 

HUSCOLOSKBLETAI SYSTEM 

NONE 

BODY CAVITIES 

•EPICARDION (20) (50) (50) 

SARCOMA , NOS, METASTATIC 1 (2%) 

*TUNICA VAGINALI S (20) (50) (50) 

MESOTHELIOHA, NOS 1 (2X) 

ALL OTHER SYSTIHS 

*MnLTIPLE ORGANS (20) (50) (50) 

MESOTHELTOl'A, NOS 1 (2%) 

THORAX 

OSTEOSARCOMA 1 

ANIMA L DISPOSITION SUMMAR Y 

ANIMALS INITIALLY IN ST1DY 20 50 50 

NATURA L DEATH9 8 1 7 

MORIBUN D SACRIFICE 1 1 2 

SCHEDULED SACRIFICE 

ACCIDENTALLY KILLED 

TERMINA L SACRIFICF 11 15 41 

ANIMA L HISSING 

2_I5£lSBIS_»fl22I-jfZED_ ANIMAL S 

* NOBBES OF ANIMALS KITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECPOPSIED
 

A-5
 
TOBOB SOBBARY
 

TOTAL ANIMALS WITH PRIBARY TOBORS*
 

TOTAL PRIMARY TTIBORS
 

TOTAL AHISALS WITH BENIGN TOBOHS
 TOTAL BENIGN TOBOSS
 

TOTAL ANIMALS WITH MALIGNANT TOHORS
 

TOTAL MALIGNANT TUMORS
 

TOTAL ANIBALS WITH SECONDART TOMORSI
 

TOTAL SECONDARY TUBORS
 

TOTAL ANIBALS WITH TOHOBS n»CERTAIH­ BENIGH OR HAIIGNAHT
 

TOTAL OHCERTAIM TOHORS
 

TOTAL ANIHALS WITH TDHOES HNCESTAINPRIMA1U 08 BETASTATIC
 

TOTAL UNCERTAIN TtTBORS
 

TABLE Al (CONCLUDED)
 

CONTROL (ONTR)


11-1045


20
 

30
 

19
 

25
 

It
 

1>
 

1
 

1
 

 LOW DOSE HIGH DOSE 

 11-1043 11-10U1 

1*5 47 

57 63 

43 47 51 50 

5 10 

5 11 

1 2 

2 4 

1 2 

1 2 

* PRIMARY TDHOFS: ALL TOBORS EXCEPT SECONDARY TOBOPS
 * SECONDARY TOBORS: HITASTATIC TOBOPS OR TOMOPS INVASIVE INTO AN ADJACENT ORGAN
 

A-6
 
TABLE A2 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN FEMALE RATS TREATED WITH TRIMETHYLTHIOUREA 

CONTROL(UNTR) LOW DOSE HIGH DOSE 

11-101(6 11-1014 11-1042 

ANIMALS INITIA1LY IN STUDY 20 50 50 

ANIMAL S NECROPSIED 20 50 50 

ANIMAL S EXAMINE D HISTOPA1HOLOGICALLY ** 20 50 50 

INTEGUMENTAR Y SYSTEM 

*SOBCDT TISSDI (20) (50) (50) 

SARCOMA, NOS 1 (2*) 

FIBROMA 2 (<|X) 

RESPIRATORY SYSTEM 

*LONG (20) (16) (49) 

ALVEOLAR/BRONCHIOLAR ADENOMA 1 (2%) 

FOILICDLAR-CELL CARCINOMA , BETAS 1 (2X) 

HEMATOPOIETIC SYSTEM 

tBRAIN (20) (50) (19)
 

HALIG.LYMPHOMA, HISTIOCYTIC TYPE 1 (2*)
 

•MULTIPLE ORGANS (20) (50) (50)
 

MALIGNANT IYMPHONA, NOS 3 (6X)
 

LEUKEMIA,NOS 1 (2X)
 

CIRCULATORY SYSTEM
 

NONE
 

EIGESTIVE SYSTEM
 

tLIVER (20) (»9) (»9)
 

HEPATOCELLDLAR ADENOMA 1 (5X)
 

NBOPLASTIC NODULE 1 (5X) 2 («*)
 

* DUODENUM (20) (50) (19)
 

t NOHBEP OF ANIMALS KITH TISSUE EXAMINED MICROSCOPICALLY 

* NUMBER OF ANIMALS NECROPSIED 

**EXCLUDES PARTIALLY AUTOLYZED ANIMALS 

A-7 
DRINAR Y SYSTEB 

NONE 

BNDOCRIHE SYSTIB 

tPITUITARY 

CHROBOPHOBI ADENOBA 

tADRENAL 

CORTICAL ADENOBA 

PHEOCHROBOCYTOBA 

ITHYROID 

FOLLICntAR-CELL ADENOHA 

FOLLICOLAP-CILL CARCTNOHA 

C-CELL ADENOBA 

C-CELL CARCINOBA 

tPANCREATIC ISLETS 

ISLET-CELL ADEHOBA 

REPRODDCTIVE SYSTEB 

*BABHARY GLAND 

ADENOCARCINOHA, NOS 

PAPILLARY ADF.NOCARCINOBA 

FIBROADENOBA 

iOTERUS 

EBDOBETRIAL STROBAL POLYP 

IOVARY 

GRANDLOSA-CELL TOBOR 

NERVOUS SYSTEB 

IBRAIM 

GLIOBA, NOS 

SPECIAL SENSE ORGAN S 

NONE 

t NOBBER OF AHIBALS WITH TISSHE

* SOHBER OF ANISALS NECROPSIED 

TABLE A2 (CONTINUED^ 

CONTROL (DNTR) LOB DOSE 

11-1016 11-1011 

(18) (11) 

2 (11%) 8 (18%) 

(20) (50) 

1 (5%) 

(17) (38) 

1 (3*) 

1 (6%) 2 (5%) 

1 (3%) 

(20) (50) 

1 (2%) 

(20) (50) 

1 (5%) 1 (2%) 

1 (5%) 1 (5%) 3 (6%) 

(20) (50) 

2 (10%) 

(20) (19) 

1 (2%) 

(20) (50) 

 EXABIHED MICROSCOPICALLY 

HIGH DOSE 

11-1012 

(17) 

11 (23%) 

(19) 

1 (2%) 

(17) 

9 (19%) 

11 (30%) 

2 (4%) 

2 (1%) 

(17) 

(50) 

6 (12%) 

(19) 

(19) 

(19) 

1 (2%) 

A-8 
NUSCULOSKELETAL SYSTEM 

NONE 

BODY CAVITIES
 

*ABDO»INAL CAVITY
 ADENOCARCINOMA, NOS, METASTATIC
 

•ABDOMINAL	 VISCERA
 

SARCOMA, NCS
 

ALL OTHER SYSTEMS
 

•MULTIPLE ORGANS
 ADENOCARCINOMA, NOS, METASTATIC
 

ANIMAL DISPOSITION SUMMARY
 

ANIMALS INITIALLY IN STUDY
 

NATURAL DEATH9
 

MORIBUND SACRIFICE
 

SCHEDULED SACRIFICE
 

ACCIDENTALLY KILLED
 

TERMINAL SACRIFICE
 

ANIMAL MISSING
 

2_INCLDDES_AD10LYZED_ANTM_ALS_
 

TABLE A2 (CONTINUED) 

CONTROL(DNTR) LOW DOSE 

11-10K6 

(20) (50)
 

(20) (50)
 

(20) (50) 

20 50 

17 38 

HIGH DOSE 

11-1012 

(50)
 

1 (2«)
 

(50)
 

1 (2*)
 

(50)
 

1 (2«)
 

50
 

11
 

7
 

32 

t NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS SECROPSIED
 

A-9
 
TABLE A2 (CONCLUDED)
 

CONTROL (UNTR) LOB DOSE HIGH DOSE 

11-10146 11-10UU 11-10U2 

TUBO" SUMMAR Y 

TOTAL ANIMAL S ( ITH PRIMAR Y TUMORS* 7 20 35

 

TOTAL PRIMAR Y TOHOPS 12 23 53

 

TOTAL ANIMAL S WITH JtJIGN TUMORS 6 13 23

 

TOTAL SEHIGN TH»ORS 9 15 31

 

TOTAL ANIMAL S IIITH MALIGNAN T TUMORS 2 5 21

 

TOTAL MALIGNAN T TOMORS 2 5 22

 

TOTAL ANIMALS WITH SECONDARY TUMORS* 3
 

TOTAL SECONDARY TUMORS 3
 

TOTAL ANIMALS WITH TUMORS UNCERTAINBENIGN OP MALIGNANT 1 3
 

TOTAL UNCERTAIN TUMORS 1 3
 

TOTAL ANIMALS WITH TUMORS UNCERTAINPRIMARY OR BETA3TATIC
 

TOTAL UNCERTAIN TUMORS
 

* PRIMARY TUBOFS: ALL TUMORS EXCEPT SECONDARY TOHORS
 

* SECONDARY 'IMORS: ""TASTATIC TUMORS OR TUMORS INVASIVE INTO AN ADJACENT ORGAN
 

A-IO
 
APPENDIX B
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS
 

IN MICE TREATED WITH TRIMETHYLTHIOUREA
 

TABLE Bl
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN MALE MICE TREATED WITH TRIMETHYLTHIOUREA
 

CONTROL (UNTR) 

22-2045 

ANIMALS INITIAILY 

JNIHALS KISSING 

IH STUD!

ANIMALS NECPOPSIED

 20 

1 19 ANIHALS EXAMINED HISTOPATHOLOGICALLY ** 19
 

INTEGUMENTARY SYSTEM
 

NONE
 

RESPIRATORY SYSTEM
 

•LUNG


ALVEOLAR/BRONCHIOLAR ADENOMA
 

ALVEOLAR/BRONCHIOLAR CARCINOHA


HEMATOPOIETIC SYSTEM
 

*MULTIPLE ORGANS
 

LEUKEHIA.SCS
 

*SPLEEN
 H£HANGIOMA
 LYBPHOCYTIC LEOKEHIA
 

*MESENTERY
 

MALIGNANT LYMPHOMA, NOS
 

CIRCULATORY SYSTEM
 

NONE
 

DIGESTIVE SYSTEM
 

*LITER
 

HEPATOCELLULAR ADENOM A 

NEOPLA§TIC_SODOLE 

t NUMBER OP ANIHALS WITH TISSTJE * NDHBER OF ANIHALS NECROPSIED 

**EXCLUDES PARTIALLY AUTOLYZED ANIMALS 

 (18)
 

1 (6»)
 

(19)
 

1 (5*)
 

(17)
 

(19)
 

(19)

5 (26X) 

J_L55i__ 

 EXAMINED MICROSCOPICALLY 

LOR DOSE
 

22-2043
 

50
 

6
 

44
 

44
 

(44)
 

3 (7%)
 

2 (5«)
 

(41) 

1 (2«) 

(44) 

2 (5*) 

HIGH DOSE
 

22-2041
 

50
 

50
 

50
 

(50)
 

6 (12%)
 

2 (4«)
 

(50)
 

(49)
 

(50)
 

1 (2*)
 

(50)

2 (4*) 

B-3 
HBHANGIOSAICORA

tSRALL INTESTINE

SARCOMA. NOS

IDQODENDH

ADENOCARCINOHA, SOS

PRIHARY SISTER 

MODE 

F.NDOCBINE SISTEN 

•THYROID

FOLLIC0LAR-CELL ADENOHA

FOLLICOLAB-CELL CASCIHOHA

mNCREATIC ISLETS

ISLET-CELL ADENOHA

BEPEODOCTIVE SISTEH 

HOME 

BBS YOU S SYSTEM 

NONE 

SPECIAL SENSE ORGANS 

*EYE/LACT)IRAL GLAND

PAPILLARY CYSTADENOCARCINOHA,NOS

HDSCTLOSKELBTAl SYSTER 

NONE 

BODY CAVITIES 

SONJ

TABLE Bl (CONTINUED) 

COHTROL (0NTR) LOW DOSE HIGH DOSE 

22-20U5 22-2043 22-2041 

1 (2<) 

 (19) (18) (50) 

1 (2%) 

 (19) (411) (50) 

1 (2X) 

 (12) (32) (MO) 

1 (8%) 

1 (3«) 

 (19) (41) (47) 

1 (2f) 

 (19) (44) (50) 

1 (2*) 

r 

t HOBBER OF ANIRAL5 KITH TISSUE EXAHINED MICROSCOPICALLY
 

* HORSES OF ANIMALS NECROPSIED
 

B-4
 
TABLE Bl (CONCLUDED)
 

CONTROL(OHTR) LOW DOSE HIGH DOSE
 

22-20K5 22-20U3 22-201*1
 

AIL OTHER SYSTEMS
 

HONE
 

ANIMAL DISPOSITION SUMMARY
 

ANIMALS INITIALLY IN STODI 20 50 50
 

NATURAL DEATH9
 

MORIBUND SACFIFICE
 

SCHEDULED SACRIFICE
 

ACCIDENTALLY KILLED
 

TERMINAL SACRIFICE 18 111 50
 ANIMAL HISSING 1 6
 

a INCLUDES AUTOLYZED ANIMALS
 

1DMOR SUMMARY
 

TOTAL ANIMALS ilTH PPIMAPY TUMORS* 8 11 15
 TOTAL PPIMARY TUMORS 9 11 15
 

TOTAL ANIMALS WITH BEHIGN TUMORS 6 7 8
 TOTAL BENIGN TUMORS 6 7 8
 

TOTAL ANIMALS WITH MALIGNANT TDMORS 2 n 7
 

TOTAL MALIGNANT TDMOBS 2 u 7
 

TOTAL ANIMALS WITH SECONDARY TOMORS*
 TOTAL SECONDARY TDMOHS
 

TOTAL ANIMALS HITH TOBO^S ONCERTAIN­ BENIGS OR MAIIGNANT 1
 

TOTAL DNCEPTAIN TDHOES 1
 

TOTAL ANIMALS WITH TDMOPS ONCEPTAINPPIHARY OR MITASTATIC
 

TOTAL ONCEPTAIN TUMORS
 

* PRIMARY TUMORS: ALL TUMORS EXCEPT SECONDARY TUMORS
 t SECONDARY TUMOPS: METASTATIC TUMORS OR THMOPS INVASIVE INTO AN ADJACENT ORGAN
 

B-5
 
TABLE B2

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN FEMALE MICE TREATED WITH TRIMETHYLTHIOUREA 

CONTROL (DNTR) 

22-2016 

LOW DOSE 

22-2044 

HIGH DOSE 

22-2042 

ANIMALS INITIAILY IN STUDY 

ANIMALS HISSING 

ANIMALS NECEOPSIEO 

AHIMALS EXAMINED HISTOPATHOLOGICALLY 

20 

1 

19 

** 19 

50 

4 

46 

46 

50 

2 

48 

48 

INTEGUMENTARY SYSTEM 

NONE 

RESPIRATORY SYSTEM 

ILUN6

ALVEOLAR/EFONCHIOLAR ADENOMA 

ALVEOLAR/BRONCHIOLAR CARCINOMA 

 (19) (46) 

1 (2*) 

(46) 

2 (4S) 

HEHATOPOIETIC SYSTEM 

*MULTIPLE ORGANS

MALIGNANT 1YMPHOMA, NOS 

LEUKEMIA. NOS

 (19) 

1 (5%) 

(46) 

1 (2%) 

(48) 

1 (2*) 

• PULMONARY LYMPH NODE

MALIGNANT LYMPHOMA, NOS 

 (13) (37) 

1 (3*) 

(39) 

IKIDNEY

MALIGNANT IYMPHOMA, NOS 

 (19) (46) (47) 

1 (2«) 

CIRCULATORY SYSTEM 

NONE 

DIGESTIVE SYSTEM 

NONE 

ORINAR Y SYSTIM 

NONE 

i NUMBER OF ANIMAL S WITH TISSUE EXABINE D

* NUMBER OF ANIMAL S NECROPSIED 

**EXCLUDES PARTIALLY AUTOLYZED ANIMALS 

 MICROSCOPICALLY 

B-6 
TABLE B2 (CONTINUED) 

CONTROL(UNTR) LOB DOSE HIGH DOSE 

22-20116 22-201I4 22-20U2 

INDOCHINE SYSTIM 

HONE 

REPRODUCTIVE SYSTEM 

t07ABY (19) (45) (<12) 

PAPILLOMA, NOS 1 (2*) 

SEB70US SYSTEH 

NONE 

SPECIAL SEHSI CBGANS 

NONE 

BOSCOLOSKELETAL SYSTEM 

NONE 

BODY CAVITIES 

NONE 

»LL OTHEn SYSTIHS 

*HtJLTIPLE ORGAN S (19) (U6) (18) 

PIBROSARCOBA 1 (2«) 

ANIHAL DISPOSIIION SOHMARY 

ANIMALS INITIALLY IN STDDY 20 50 50 

NATUHiL DEATH9 3 1 5 

MOBIBOND SACRIFICE 1 2 

SCHEDULED SACRIFICE 

ACCIDENTALLY KILLED 

TEFHINAL SACRIFICE 15 H3 «3 

ANIHA L HISSING 1 « 2 

S_IfiCLDDES_A2TOI.YZED_ANIHAI.S 

* NUMBER OF ANIHALS WITH TISSUE EIABINED MICROSCOPICALLY * NUMBER OF ANIMALS NECROPSIED 

B-7 
TABLE B2 (CONCLUDED)
 

CONTROL (UNTR) LOW DOSE HIGH DOSE
 

22-2046 22-2044 22-2042
 

TUMOR SUMMARY
 

TOTAL ANIHALS WITH PRIMARY TUMORS* 1 3 4
 TOTAL PRIMARY TDHORS 1 5 4
 

TOTAL ANIMALS WITH BENIGN TDMORS 1
 

TOTAL BENIGN TUMORS 2
 

TOTAL ANIMALS WITH MALIGNANT TDMORS 1 2 4
 

TOTAL MALIGNANT TUMORS 1 3 4
 

TOTAL ANIMALS WITH SECONDARY TDMORS*
 

TOTAL SECONDARY TOMOPS
 

TOTAL ANIMALS WITH TDMORS UNCERIAIN­ BENIGN OR MALIGNANT
 

TOTAL UNCERTAIN TDMORS
 

TOTAL ANIMALS WITH TDMORS UNCERTAINPRIMARY OR MITASTATIC
 

TOTAL UNCERTAIN TUMORS
 

* PRIMARY TUHORS: ALL TUMORS EXCEPT SECONDARY TUMORS
 

I SECONDARY TUMORS: METASTATIC TUMORS OR TUMORS INVASIVE INTO AN ADJACENT ORGAN
 

B-8
 
APPENDIX C
 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC
 

LESIONS IN RATS TREATED WITH TRIMETHYLTHIOUREA
 

TABLEC1

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN MALE RATS 

TREATED WITH TRIMETHYLTHIOUREA

 

CONTROL (ONTR) LOW DOS? HIGH DOSS 

11-1045 11-1043 11-1041 

ANIMALS ISITIftlLY IN STUDY 20 50 50 

ANIMAL S NECROPEIED 20 50 50 

ANIMALS EXAMINE D HISTOPATHOLOGICALLY ** 20 50 49 

INTEGUMENTAR Y SYSTEM 

*SKIN (20) (50) (50) HULTILOCULAR CYST 1 (2X) 

RESPIRATOR Y SYSTEM 

*LUNG (20) (45) (49)
 

BHONCHOPNEUMONIA, FOCAL 1 (2X)
 

PNEUMONIA, CHRONIC MURINE 8 (40*) 6 (13%) 25 (51X)
 

HEMATOPOIETIC SYSTEM
 

NONE
 

CirCOLATORY SYSTEM
 

tMYOCABDIIIM (20) (50) (49)
 

INFLAMMATION, CHRONIC 1 (2%)
 

FIBfOSIS 1 (5%) 3 (6X) 2 (4«)
 

DEGENERATION, NOS 1 (2*) 4 (815)
 

DIGESTIVE SYSTIM
 

*LITER (20) (49) (49) 

GRANULOMA . NOS 1 (2«) 

METAMOPPHOSI S FATTY 1 (5X) 1 (2X) 1 (2X) 

tLIVEP/CENTFILOEHLAE (20) (49) (49) 

NECROSIS, NOS 1 (5%) 

• LIVER/PE1IPOFTAL (20) (49) . (49) 

FIBROSIS 2_(JOSX 

« NUMBER OF ANIMAL S WITH TISSUE EXAMINE D MICROSCOPICALLY 

* NUMBER OF ANIMAL S NECPOPSIED 

"EXCLUDES PARTIALLY AUTOLYZED ANIMALS 

C-3 
TABLE Cl (CONTINUED)
 

" COSTSOL (DNTP) LOW DOSE 

11-1045 11-1043 

•LIVEB/HEPATOCYTES (20) (49) 

NECROSIS, DIFFUSE 

•PANCREATIC ACINUS (20) (49) 

ATROPHY, NOS 1 <5X) 

•SMALL INTESTINE (20) (49) 

HYPERPLASIA, LYMPHOID 1 (2<) 

tLARGE INTESTINE (20) (49) 

N^MATODIASIS 1 (5%) 1 (2«) 

URINARY SYSTEM 

•KIDNEY (20) (50) 

CYST, NOS 1 (2%) 

INFLAMMATION, CHRONIC 12 (60X) 31 (62%) 

• URINARY BLADDER (19) (46) 

CALCULUS, NOS 2 (M) 

EIDOCRINB SYSTEM
 

•PITUITARY	 (17)
 

HEMORRHAGIC CYST 1 (2«)
 

• ADRENAL (20) (50) 

HEHOFRHAGIC CYST 1 (2*) 

LIPOIDOSI"; 1 (2%) 

tADRENAL MEDULLA (20) (50) 

CYST, NOS 1 (5%) 

HYP"RPLASIA, NOS 

•THYROID (17) (37) 

HYPERPLASIA, C-CELL 

•PANCREATIC ISLETS (20) (49) 

HYPERPLASIA, NOS 1 (2*) 

HEPPODUCTIVE SYSTEM
 

•TESTIS	 (20) (50)
 

GEAN2iOJii_SPERMATI£
 

I NGHBER OP ANIMALS BITH TISSUE EXAMINED MICROSCOPICALLY
 

* NOHBEP OF ANIMALS NECPOPSIED
 

HIGH DOSE 

11-1041 

(49)

1 (2%) 

(49) 

3 (6*) 

(49) 

(49) 

4 (8«) 

(« 9) 

35 (71%) 

(45) 

(36)
 

(49) 

1 (2«) 

(49) 

1 (2%) 

(39) 

1 (3«) 

(49) 

(49)
 

C-4
 
TABLE Cl (CONCLUDED) 

CYTOHEGALY

HYPEHPLASIA, INTERSTITIAL

UTESIIS/TOBULE

MINERALIZATION

 CELL

COITROL(OHTR)

11-1015

 (20)

 1 (5«) 

 LOS DOSE

 11-1013

 1 (2*) 

1 (2«) 

 (50)

 HIGH DOSE 

 11-1011 

 (19) 

NERVOUS SYSTEM 

NONE 

SPECIAL

NONE 

 SENSE ORGAHS 

BOSCOLOSKELETAI

NONE 

 STSTEH 

BODY CAVITIES 

*PLEORA

HTDPOTHOHA X

 (20)

 1 (5*) 

 (50) (50) 

ALL OTHER

NONE 

 SYSTEMS 

SPECIAL BORPHOLOGY SDBHiBI 

HO LESION FEPORTED

iOTO/HECtOPSY/IO HISTO

* NUHBER OF ANIHALS RITE TISSOE

* N011BEB OP ARIHALS NECSOPSIED 

 EXAHISED HICROSCOPICALLI 

2 

1 

C-5 
TABLE C2

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN FEMALE RATS 

TREATED WITH TRIMETHYLTfflOUREA 

^__« —________________ _ ._______.________.*_ _ 

COBTHOL(OBTR)

11-10*6

 LOW

 11

 DOSE

-W4

 HIGH

 11-1

 DOSE 

0142 

1BIHALS IBITIAILY IB STODY 20

ANIHALS NECPOPSIED 20

'ABIHALS EXAHIBED HISTOPATHOLOGICALLY ** 20

 50

 50

 so

 50 

 50 

 50 __»__..___ _— — __—.—_ ___ __________ _ _______ _ __

IBTEGOHENTARY SI Sim 

*SKI» (20) (50) (50) 

CYST, BOS 1 (2«) 

•SOBCOT TISSUE (20) (50) (50)
 

ABSCESS, NOS 1 (2*)
 

BESPIRATOSr SYSTEM
 

«LO»G (20) (46) (49)
 

BHOWCHOPMEDMOHIA, ACDTE 1 (2X)
 

IHFLARHATIOB, ACDTB SOPPD8»TI?E 1 (2X)
 

P»EOHOHIA, CHROHIC BDRUE 3 (15X) 8 (17X) 9 (18«)
 

11IFLABRATION, GRABULOHATOOS 1 (2%)
 

REACTIOB, FOREIGN BODY 1 (2%)
 

BBNATOPOIETIC SYSTEM
 

NONE
 

CIRCULATORY SYSTEH
 

tHYOCARDIOH (19) (47) (39)
 

IHFLAHHATICB, BOS 1 (2%)
 

PIBROSIS 1 (2*)
 

DBGEBERATIOB, BOS 1 (2X) 2 (5X)
 

DISESTITB SYStlH
 

*LITBH (20) (49) (49)
 CIST, -12S
 

f BflHBER OF ABIHALS WITH TISSUE EXAHINED HICROSCOPICALLY 

* BOBBER OF ABIHALS BECROPSIBD 

**EXCLUDES PARTIALLY AUTOLYZED ANIMALS 

C-6 
NBCHOSIS, FOCAL
 METAMORPHOSIS FATTY
 

#LIVER/P?RIPOFTAL
 METAMORPHOSIS FATTY
 

tPANCPEATIC SCINDS
 

ATBOPHY, NCS
 

•STOMACH
 EPIDERMAL INCLUSION CYST
 

tSHALL INTESTINE
 HYPEPPLASIA, LYHPHOID
 

tLARGE INTESTINE
 NEHATODIASIS
 

OPINARY SYSTEM
 

tKIDNEY
 HYDPONEPHROSIS
 INFLAMMATION. NOS
 INFLAMMATION, CHRONIC
 CALCIFICATION. FOCAL
 

ENDOCRINE SYSTEM
 

1PITUITARY
 CYST, NOS
 HEHOKBHAGIC CYST
 

tADHENAL
 HEBORHHAGIC CYST
 METAMORPHOSIS FATTY
 LIPOIDOSIS
 

•ADPENAL	 CORTIX
 HYPE1PLASIA, NOS
 HYPERPLASIA, FOCAL
 

tTHYROID
 FOLLICDLAR_CISTJ. HOS
 

* NUMBER OF ANIMALS KITH TISSDE

* NDPIBES OF ANIMALS NECROPSIED 

TABLE C2 (CONTINUED) 

COHTPOL (DHTB) LOW DOSE
 

11-10U6 11-10ll»
 

1 (2t)
 

t (8%)
 

(20) (U9)
 

(20)	 (50)
 

1 <5X) 1 (2«)
 

(20) (50)
 

(20) (50)
 

(20)	 (50)
 

1 (5%) 1 (2«)
 

(20) (50)
 

2 (10%) 16 (32X)
 

1 (5«)
 

(18) ("»"•)
 

2 (5*)
 

1 (6*) 3 (7«)
 

(20)	 (50)
 

1 <5X) 3 (6«)
 

1 (2«)
 

2 (U»)
 

(20)	 (50)
 

1 (2X)
 

(17)	 (38)
 

-_ 2_J5S)L_ _
 

 EXAMINED MICROSCOPICALLY 

HI SB DOSE
 

11-10I»2
 

«	 (8X)
 

(U9)
 

1 (2»)
 

(117)
 

(t9)
 

1 <2X)
 

(It 9)
 

1 (2«)
 

(49)
 

2 (»%)
 

(50)
 

1 (2»)
 

1 (2*)
 

20 (KOt)
 

(U7)
 

3 (6%)
 

(19)
 

1 (2%)
 

1	 (2*)
 

(U9)
 

1	 (2*)
 

(*7)
 

_... H--T-- _n __—__——..
 

C-7 
TABLE C2 (CONTINUED) 

CONTROL (UNTR)

11-10146

 LOW DOSE 

 11-1044 

INFLABBATICN, NOS 

HYPERPLASIA, C-CELL

HYPERPLASIA, FOLLICULAR-CBLL 

1 (3%) 

REPRODUCTIVE SYSTEB
 

*BABBARY GLANI (20) (50)
 

INFLABBATICN, VESICULAR
 

ABSCESS, NOS
 

INFLABBATICN, CHRONIC 1 (2X)
 

tUTERUS (20) (50)
 

THROBBUS, ORGANIZED 1 (2X)
 

I»FLABBATION, NOS
 

INFLABBATION, SDPPURATIVE 1 (2%)
 

PYOBETRA
 

INFLABBATICN, ACUTE 1 (5X)
 

INFLABBATION, ACUTE SUPPDRATIVE
 

tUTERUS/ENDOBITRIUH (20) (50)
 

CYST, NOS 1 (5X)
 

INFLABBATION, SUPPURATIVE
 

INFLABHATICN, VESICULAR 1 (2X)
 

((OVARY/OVIDUCT (20) (50)
 

INFLABBATION, ACUTE SUPPDRATIVE
 

*OVARY (20) (49)
 

CYST, NOS 1 (2X)
 

PAROVARIAN CYST 3 (15X) 2 (4%)
 

NERVOUS SYSTEB
 

NONE
 

SPECIAL SENSE ORGAN S 

NONE 

HOSCULOSKELETAI SYSTEB 

NONE 

* NOBBEH OF ANIBALS HITH TISSUE EXABINED BICROSCODICALLY 

* NDBBE"! OF ANIBALS NECROPSIED 

HIGH DOSE
 

11-1042
 

1 (2X)
 

3 (6X)
 

(50)
 

1 (2X)
 

1 (2X)
 

(49)
 

2 (4X)
 

1 (2X)
 

1 <2X)
 

(49)
 

1 (2X)
 

1 (2X)
 

(49)
 

1 (2X)
 

(49)
 

2 (4X)
 

6 (12%)
 

P- u o 8
TABLE C2 (CONCLUDED) 

CONTROL (DHTR)

11-10U6

 LOW DOSS

 11-10HU

 HIGH DOSE 

 11-1042 

BODY CAVITIE S 

*EPICARDinH

INFLAMMATION, NOS

*MESENTEnY

NECROSIS, FAT

 (20)

 (20)

 (50)

 (50)

 (50) 

1 (2*) 

 (50) 

1 (2%) 

ALL OTHER SYSTIMS 

NONE 

SPECIAL MORPHOLOGY SDM8ARY 

NO LESION EEPORTED 6 10

AUTO/NECROPSY/HISTO PBRF 1

t SOMBER OP ANIHALS WITH TISSUE EXAHIHBD HICSOSCOPICALLI 

* NHMBER OF ANIBALS NECROPSIED 

1 

1 

C-9
 

APPENDIX D
 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC
 

LESIONS IN MICE TREATED WITH TRIMETHYLTHIOUREA
 

TABLE Dl

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN MALE MICE 

TREATED WITH TRIMETHYLTHIOUREA 

CONTROL(OHTR) LOB DOSE

22-2045 22-2043

 HISH DOSE 

 22-2041 

iNIHALS INITIALLY IN STBDY 20

ANIRALS HISSING 1

ANIHALS NSCROPSIED 19

ARIHALS EXAMINED HISTOPATHOLOGICALLY ** 19

 50

 6 

 44

 44

 50 

 50 

 50 

INTEGUHENTARY SYS1BH
 

NONE
 

PESPIHATOHY SYSTEH
 

tLONG (18) (44) (50)
 

PNEOHONIA, CHRONIC fit)RISE 1 (2%) 1 (2%)
 

HYPERPLASIA. EPITHELIAL 1 (2«)
 

HYPERPLASIA, ADENOHATOOS 1 (2%)
 

HEHATOPOIETIC SYSTEH
 

•SPLBEN	 (17) (41) (49)
 

HYPEROLASIA, LYHPHOID 1 (2X) 2 (4%)
 

tHESENTERIC L. NODE (14) (43) (47)
 

INFLAHHATION, HEBORRHAGIC 1 (2«)
 

INFLAHHATION, GRANDLOHATOUS 1 (7%)
 

HYPBRPLASIA, LYHPHOID 2 (5t) 1 (2%)
 

CIRCULATORY SYSTEH
 

NONE
 

DIGESTIVE SYSTIH
 

*LIVER (19) (4U) (50)
 

INFLAHHATION, NOS 1 (2«)
 

GRANDLOHA, NOS 2 (4t)
 

» NDBBEP OF ARIHALS WITH TISSDE EXAHINBD HICROSCOPICALLY 

* NUMBER OF ANIHALS NECROPSIED 

**EXCLUDES PARTIALLY ABTOLYZED ANIMALS 

D-3
 
TABLE Dl (CONTINUED)
 

CONTROL(UNTR) LOR DOSE HIGH DOSE
 

22-2045 22-2013 22-20W1
 

HYPERPLASIA. MOS 1 (2*)
 

iPANCPEAS (19) (41) (47)
 ECTOPIA 1 (2*)
 

CYSTIC DUCTS 1 (2%)
 

tSMALl INTESTINE (19) (44) (50) 

INFLAMMATION, G'ANOLOHATOUS 1 (2*) 

HYPERPIASIA, RETICOLDH CELL 1 (2*) 

HYPERPLASIA, LYMPHOID 1 (2%) 

*LARGE INTESTINE (19) (44) (50)
 

NEHATODIASIS 4 (21*) 8 (18*) 9 (18%)
 

DPINABY SYSTEM
 

IKIDNEY (19) (44) (50)
 

HYDRONEPHROSIS 1 (2«) 1 (2*)
 

INFLAHMATION, CHRONIC 3 (16*) 1 (2*)
 

NEPHROPATHY 1 (2*)
 

ENDOCRINE SYSTBS
 

ITHYfiOID (12) (32) (40)
 

GOITE" COLLOID 1 (3X)
 

HYPEPPLASIA, C-CELL 2 (5*)
 

REPRODUCTIVE SYSTEH
 

*MA(laARY GLAN D (19) (44) (50) 

DILATATION/DUCTS 1 (2%) 

NERVOU S SYSTEM 

tBRAIN (19) (44) (49) 

CORPORA ftHYLACEA 6 (32*) 11 (25X) 17 (35*) 

SPECIAL SENSE OPGANS 

NONE 

t NOHBEF OF ANI1ALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

D-4
 
TABLE Dl (CONCLUDED) 

CONTROL(OHTF) LOW DOSF HIGH DOSE 

22-20U5 22-20U3 22-20U1 

MtlSCnLOSKELETAL SYSTEM 

•SKELETAL BOSCLE (19) (HI) (50) 

INFLAMMATION. NOS 1 (2») 

INFLAMMATION. FOCAL 1 (2X) 

BODY CAVITIES 

NONE 

ALL OTHER SYSTEMS 

NONE 

SPECIAL MORPHOLOGY SHMHAH Y 

NO LESION HEPOBTED 5 19 15 

ANIHAL HISSING/NO NECROPSY 1 6 

I NUMBER OF ANIMAL S SITH TISSUE EXAHINED MICROSCOPICALLY * NUMBER OF ANIMALS NECROPSIED 

D-5 
TABLE D2

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN FEMALE MICE 

TREATED WITH TRIMETHYLTHIOUREA 

CONTROL (OHTB) LOW DOSE HIGH DOSE
 

22-2046 22-2044 22-2042
 

ANIMALS INITIALLY IN STUDY 20 50 50
 ANIMALS MISSING 1 4 2
 ANIMALS NEC»OPSIED 19 46 48
 ANIMALS EXAMINED HISTOPATHOLOGICALLY ** 19 46 48
 

INTEGUMENTAR Y "STEM 

NONE 

BFSPIRATORY SYSTEM
 

ILUNG (19) (46) (46)
 LYMPHOCY~T~ INFLAMMATORY INFILTR 1 (2*)
 PNEUMONIA, CHRONIC BURINE 4 (21*) 3 (7«)
 GRANULOI' f NOS 1 (2*)
 

HEMATOPOIETlt SYSTEM
 

fSPLEEN (19) (42) (47)
 HuMORPHAGIC CYST 1 (2«)
 

ILYMPH NODE (13) (37) (39)
 HYPEEPLASIA, NOS 1 (3*)
 HYPERPLASIA, RETICULOB CELL 1 (3*)
 

IBESENTEBIC L. NODE (13) (37) (39)
 HYPEB^LASIA, LYMPHOID 1 (8X)
 

CIRCULATORY SYSTEM 

NONE 

DIGESTIVE SYSTEM 

(19) (45) (48) ____ INFLAMMATIONt_ACUTE_FOCAL 

* NUBBPP OF ANIMAL S »ITH TISSUE EXAMINED HICHOSCOPICALLY 

* NUMBEP OF ANIMALS NECROPSIED 

**EXCLUDES PARTIALLY AUTOLYZED ANIMALS 

D-6 
TABLE D2 (CONTINUED)
 

CONTROL (ONTR) LOW DOSE 

22-20 M6 22-204U 

GRANOLOHA, NOS 

HYPERPLASIA, NODULAR 1 (5%) 1 (2%) 

HYPERPLASIA, NOS 1 (2t) 

IPANCRKAS 

CYSTIC DOCTS 

(18) (It) 

*PANCPEATIC ACINOS (18) (44) 

ATROPHY, MOS 

*PEYERS PATCH (18) (46) 

HYPERPLASIA, LYHPHOID 1 (6%) 

•LARGE INTESTINE (17) (45) 

HEN AT ODI AS IS 1 (6*) 

DRIHARY SYSTER 

•KIDNEY (19) (46) 

INFLAMMATION, CHRONIC 2 (11%) 2 {«) 

PBRIVASC01AR COFFING 1 (2%) 

ENDOCRINE SYSTEH 

•THYROID (16) (37) 

GOITER COLLOID 1 (6%) 

IPARCEEATIC ISLETS (18) (44) 

HYPERPLASIA, NOS 

REPRODDCTI7E SYSTEH 

(trtTEBOS (19) (46) 

HYDROHETRA 2 (11*) 

HEMORRHAGE 

PYOHETRA 1 (2*) 

ABSCESS, DOS 

»CBRVIX OTERI (19) (46) 

INFLAHHATION, DOS 

fOTEHOS/ZNDOBETRinH (19) (46) 

__£ISSi H°S _ _ _ _I_I5SI_ _. 

t NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NDMBEB OF ANIMALS NECROPSIED
 

HIGH DOSE 

22-2042 

1 (2%) 

1 (2%) 

(45) 

1 (2*) 

(45) 

1 (2*) 

(47) 

(45) 

(47) 

(38) 

(45) 

1 <2X ) 

(45) 

1 (2*> 

1 (2X) 

1 (2*) 

(45) 

1 (2X) 

(45) 

1 (2X1 

D-7
 
TABLE D2 (CONTINUED) 

CONTROL(DNTR)

22-2046

 LOW DOSE

 22-2044

 HIGH DOSE 

 22-2012 

INFLAMMATION, BOS

INFLAMMATION, SOPPORATIVTi

INFLAMMATIOH, ACUTE

HYPE»PLASIA. NOS

HYPERPLASIA. CYSTIC

*OVAEY

CYST, HOS

FOLLICTJLAF CYST, NOS

 1 (5%)

 1 (5*) 

6 (32*)

 (19)

 5 (26*)

 2 (4*) 

1 (2X)

 2 (4X)

 12 (26*)

 (45)

 5 (11*)

 1 (2*) 

1 (2X) 

1 (2%) 

 HI (31*) 

 (42) 

8 (19*) 

RE*VOUS SYSTEM 

tBPSIN/NENINGFS

LYMPHOCYTIC INFLAMMATOR Y INFILTP

*BPAIN

CORPORA AMYLACE A

INCLUSION, CYTOPLASHIC

 (19)

 1 (5X)

 (19)

 4 (21*)

 (45)

 1 (2X)

 (45)

 13 (29*)

 1 (2*) 

 (48) 

1 (2*) 

 (48) 

 17 (35X) 

SPECIAL SENSE ORGANS 

NOME 

MUSCULOSKELETAL SYSTEM 

NONE 

BODY CAVITIES 

NONE 

ALL OTHER SYSTEMS 

*MOLTIPLE ORGAN S

"ERIVASCOLAR CDFFING

 (19) (46)

 1 (2*) 

 (48) 

SPECIAL MORPHOLOG Y SUMMAR Y 

NQ_LESIQN_FBPORTEp

I NOHBE" OF ANIJALS WITH TISSUE

* NUMBER OF ANIMALS NECROPSIED 

 EXAMINED

 5 10 

 MICROSCOPICALLY 

D-8 
TABLE D2 (CONCLUDED)
 

CONTROL (DNTR) LOW DOSE HIGH DOSE

 

22-2046 22-204U 22-2042

 

ANIMA L HISSING/NO NECROPSY 1 i) 2 

AUTO/NECFOPSY/HISTO PERF 1 3 

* SU8BER OP MIIHALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NDBBEE OF ANIMALS NECROPSIED
 

D-9
 


DHEW Publication No. (NIH) 79-1384