bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatty Acid Desaturation and the Regulation of Adiposity in Caenorhabditis elegans
Authors: Brock Trisha J , Browse John , Watts Jennifer L
Published: April 2007

Monounsaturated fatty acids are essential components of membrane and storage lipids. Their synthesis depends on the conversion of saturated fatty acids to unsaturated fatty acids by Δ9 desaturases. Caenorhabditis elegans has three Δ9 desaturases encoded by the genes fat-5, fat-6, and fat-7. We generated nematodes that display a range of altered fatty acid compositions by constructing double-mutant strains that combine mutations in fat-5, fat-6, and fat-7. All three double-mutant combinations have reduced survival at low temperatures. The fat-5;fat-6 double mutants display relatively subtle fatty acid composition alterations under standard conditions, but extreme fatty acid composition changes and reduced survival in the absence of food. The strain with the most severe defect in the production of unsaturated fatty acids, fat-6;fat-7, exhibits slow growth and reduced fertility. Strikingly, the fat-6;fat-7 double-mutant animals have decreased fat stores and increased expression of genes involved in fatty acid oxidation. We conclude that the Δ9 desaturases, in addition to synthesizing unsaturated fatty acids for properly functioning membranes, play key roles in lipid partitioning and in the regulation of fat storage.
Involvement of the Mitochondrial Protein Translocator Component Tim50 in Growth, Cell Proliferation and the Modulation of Respiration in Drosophila
Authors: Sugiyama Shin , Moritoh Satoru , Furukawa Yoshimi , Mizuno Tomohiko , Lim Young-Mi , Tsuda Leo , Nishida Yasuyoshi
Published: April 2007

Allelic mutants exhibiting growth defects in Drosophila were isolated. Molecular cloning identified the responsible gene as a budding yeast Tim50 ortholog, and thus it was named tiny tim 50 (ttm50). The weak allele (ttm50Gp99) produced small flies due to reduced cell size and number, and growth terminated at the larval stage in the strong alleles (ttm50IE1 and ttm50IE2). Twin-spot analysis showed fewer cells in ttm50Gp99 clones, whereas ttm50IE1 clones did not proliferate, suggesting that the gene has an essential cellular function. Tim50 is known to maintain mitochondrial membrane potential (MMP) while facilitating inner-membrane protein transport. We found that tagged Ttm50 also localized to mitochondria and that mitochondrial morphology and MMP were affected in mutants, indicating that mitochondrial dysfunction causes the developmental phenotype. Conversely, ttm50 overexpression increased MMP and apoptosis. Co-expression of p35 suppressed this apoptosis, resulting in cell overproliferation. Interestingly, ttm50 transcription was tissue specific, corresponding to elevated MMP in the larval midgut, which was decreased in the mutant. The correlation of ttm50 expression levels with differences in MMP match its proposed role in mitochondrial permeability barrier maintenance. Thus a mitochondrial protein translocase component can play active roles in regulating metabolic levels, possibly for modulation of physiological function or growth in development.
A Polygenic Hypothesis for Sex Determination in the European Sea Bass Dicentrarchus labrax
Authors: Vandeputte Marc , Dupont-Nivet Mathilde , Chavanne Hervé , Chatain Béatrice
Published: April 2007

Polygenic sex determination, although suspected in several species, is thought to be evolutionarily unstable and has been proven in very few cases. In the European sea bass, temperature is known to influence the sex ratio. We set up a factorial mating, producing 5.893 individuals from 253 full-sib families, all reared in a single batch to avoid any between-families environmental effects. The proportion of females in the offspring was 18.3%, with a large variation between families. Interpreting sex as a threshold trait, the heritability estimate was 0.62 ± 0.12. The observed distribution of family sex ratios was in accordance with a polygenic model or with a four-sex-factors system with environmental variance and could not be explained by any genetic model without environmental variance. We showed that there was a positive genetic correlation between weight and sex (rA = 0.50 ± 0.09), apart from the phenotypic sex dimorphism in favor of females. This supports the hypothesis that a minimum size is required for sea bass juveniles to differentiate as females. An evolution of sex ratio by frequency-dependent selection is expected during the domestication process of Dicentrarchus labrax populations, raising concern about the release of such fish in the wild.
Multiple Trans-Sensing Interactions Affect Meiotically Heritable Epigenetic States at the Maize pl1 Locus
Authors: Gross Stephen M , Hollick Jay B
Published: April 2007

Interactions between specific maize purple plant1 (pl1) alleles result in heritable changes of gene regulation that are manifested as differences in anthocyanin pigmentation. Transcriptionally repressed states of Pl1-Rhoades alleles (termed Pl′) are remarkably stable and invariably facilitate heritable changes of highly expressed states (termed Pl-Rh) in Pl′/Pl-Rh plants. However, Pl′ can revert to Pl-Rh when hemizygous, when heterozygous with pl1 alleles other than Pl1-Rhoades, or in the absence of trans-acting factors required to maintain repressed states. Cis-linked features of Pl1-Rhoades responsible for these trans-sensing behaviors remain unknown. Here, genetic tests of a pl1 allelic series identify two potentially separate cis-linked features: one facilitating repression of Pl-Rh and another stabilizing Pl′ in trans. Neither function is affected in ethyl-methanesulfonate-induced Pl1-Rhoades derivatives that produce truncated PL1 peptides, indicating that PL1 is unlikely to mediate trans interactions. Both functions, however, are impaired in a spontaneous Pl1-Rhoades derivative that fails to produce detectable pl1 RNA. Pl′-like states can also repress expression of a pl1-W22 allele, but this repression is not meiotically heritable. As the Pl′ state is not associated with unique small RNA species representing the pl1-coding region, the available data suggest that interactions between elements required for transcription underlie Pl1-Rhoades epigenetic behaviors.
Adaptive Walks Toward a Moving Optimum
Authors: Collins Sinéad , de Meaux Juliette , Acquisti Claudia
Published: April 2007

We investigate how the dynamics and outcomes of adaptation by natural selection are affected by environmental stability by simulating adaptive walks in response to an environmental change of fixed magnitude but variable speed. Here we consider monomorphic lineages that adapt by the sequential fixation of beneficial mutations. This is modeled by selecting short RNA sequences for folding stability and secondary structure conservation at increasing temperatures. Using short RNA sequences allows us to describe adaptive outcomes in terms of genotype (sequence) and phenotype (secondary structure) and to follow the dynamics of fitness increase. We find that slower rates of environmental change affect the dynamics of adaptive walks by reducing the fitness effect of fixed beneficial mutations, as well as by increasing the range of time in which the substitutions of largest effect are likely to occur. In addition, adaptation to slower rates of environmental change results in fitter endpoints with fewer possible end phenotypes relative to lineages that adapt to a sudden change. This suggests that care should be taken when experiments using sudden environmental changes are used to make predictions about adaptive responses to gradual change.
Loss-of-Function Alleles of the JIL-1 Histone H3S10 Kinase Enhance Position-Effect Variegation at Pericentric Sites in Drosophila Heterochromatin
Authors: Bao Xiaomin , Deng Huai , Johansen Jørgen , Girton Jack , Johansen Kristen M
Published: April 2007

In this study we show that loss-of-function alleles of the JIL-1 histone H3S10 kinase act as enhancers of position-effect variegation at pericentric sites whereas the gain-of-function JIL-1Su(var)3-1[3] allele acts as a suppressor strongly supporting a functional role for JIL-1 in maintaining euchromatic chromatin and counteracting heterochromatic spreading and gene silencing.
Year-Class Formation of Upper St. Lawrence River Northern Pike
Authors: Smith Brian M. , Farrell John M. , Underwood H. Brian , Smith Stephen J.
Published: April 2007

Variables associated with year-class formation in upper St. Lawrence River northern pike Esox lucius were examined to explore population trends. A partial least-squares (PLS) regression model (PLS 1) was used to relate a year-class strength index (YCSI; 1974–1997) to explanatory variables associated with spawning and nursery areas (seasonal water level and temperature and their variability, number of ice days, and last day of ice presence). A second model (PLS 2) incorporated four additional ecological variables: potential predators (abundance of double-crested cormorants Phalacrocorax auritus and yellow perch Perca flavescens), female northern pike biomass (as a measure of stock–recruitment effects), and total phosphorus (productivity). Trends in adult northern pike catch revealed a decline (1981–2005), and year-class strength was positively related to catch per unit effort (CPUE; R2 = 0.58). The YCSI exceeded the 23-year mean in only 2 of the last 10 years. Cyclic patterns in the YCSI time series (along with strong year-classes every 4–6 years) were apparent, as was a dampening effect of amplitude beginning around 1990. The PLS 1 model explained over 50% of variation in both explanatory variables and the dependent variable, YCSI first-order moving-average residuals. Variables retained (N = 10; Wold's statistic ≥ 0.8) included negative YCSI associations with high summer water levels, high variability in spring and fall water levels, and variability in fall water temperature. The YCSI exhibited positive associations with high spring, summer, and fall water temperature, variability in spring temperature, and high winter and spring water level. The PLS 2 model led to positive YCSI associations with phosphorus and yellow perch CPUE and a negative correlation with double-crested cormorant abundance. Environmental variables (water level and temperature) are hypothesized to regulate northern pike YCSI cycles, and dampening in YCSI magnitude may be related to a combination of factors, including wetland habitat changes, reduced nutrient loading, and increased predation by double-crested cormorants.
Fish Distribution, Abundance, and Behavior along City Shoreline Types in Puget Sound
Authors: Toft Jason D. , Cordell Jeffery R. , Simenstad Charles A. , Stamatiou Lia A.
Published: April 2007

Shoreline modifications, such as bulkheads, riprap, and overwater structures, have altered many of the natural habitats in nearshore urbanized areas surrounding coastal cities, including those in Puget Sound, Washington. The effects of such structures on ecological processes are poorly known, especially those impacting juvenile salmonids Oncorhynchus spp. The goal of our study was to compare the relative abundance and behavior of juvenile salmonids and other fishes along various modified and undeveloped shoreline types. We used enclosure nets and snorkel surveys to sample fishes during high tides in areas adjacent to shore at five main habitat types: cobble beach, sand beach, riprap extending into the upper intertidal zone, deep riprap extending into the subtidal zone, and the edge of overwater structures. Bottom-dwelling fishes exhibited the only significant differences in density among cobble beach, sand beach, and riprap that extended into the upper intertidal zone. This suggests that substrate type and slope are important influences on fish densities when shoreline modifications only extend into the upper intertidal zone. Differences in pelagic fish density and behavior were more evident when shoreline modifications extended into shallow subtidal waters, truncating the shallow-water zone and creating deep water at the shoreline. We typically found higher fish densities, larger schools of salmon, and fewer terrestrial riparian insects in salmon diets at these sites. Juvenile salmonids avoided swimming beneath overwater structures, whereas surfperch (family Embiotocidae), crabs (infraorder Brachyura), and sculpins (family Cottidae) were observed beneath or adjacent to pilings. Overall, our results indicate that shoreline modifications have the greatest effect on nearshore fish assemblages when the alterations extend from the supratidal zone into the subtidal zone. Our data suggest that the differences in fish behavior and usage between modified and unmodified shorelines were caused by physical and biological effects of the modifications, such as changes in water depth, slope, substrate, and shoreline vegetation.
Outcomes assessment of an alternative career choice program
Authors: Farnsworth Charles C. , Fiechtner Leslie A.
Published: April 2007

Objective—To assess the outcomes of an alternative track program designed to address shortages of veterinarians in nonpractice areas of the veterinary profession.

Design—Telephone survey.

Study Population—Recent veterinary graduates.

Procedures—A telephone survey of recent graduates from the Texas A&M University College of Veterinary Medicine and Biomedical Sciences Alternative Career Choice program was conducted. Respondents were asked to give open-ended responses to a list of 9 interview questions.

Results—Of the 21 alternative career choice students who graduated between the years 2000 and 2005, 17 were interviewed.

Conclusion—Analysis of the data suggested that it may be possible to decrease the total number of weeks allotted to the alternate career choice program without impairing the ability of graduates to find employment in their chosen career fields.
Use of chemical ablation with trichloroacetic acid to treat eyelid apocrine hidrocystomas in a cat
Authors: Yang Shih-Hung , Liu Chen-Hsuan , Hsu Chia-Da , Yeh Lih-Seng , Lin Chung-Tien
Published: April 2007

Case Description—A 7-year-old Persian cat was evaluated for recurrence of multiple cystic periocular masses. A number of cyst-like lesions had been resected from the left eyelids 18 months earlier, with lesions recurring within 6 months after surgery. The cat had blepharospasm and signs of discomfort following rupture of the largest cyst the day prior to examination. Previous histologic examination of the cysts had revealed apocrine hidrocystomas.

Clinical Findings—Multiple pigmented nodules were seen around the skin of the upper and lower left eyelids. The nodules were brownish to black, round, soft, and fluid-filled. Signs of pain were not evident during palpation of the nodules.

Treatment and Outcome—The largest cyst on the upper eyelid was removed by means of a V-shaped full-thickness excision. Histologic and immunohistochemical examination of the excised tissue confirmed the diagnosis of apocrine hidrocystoma. The remaining periocular cysts were surgically debrided and then treated topically with 20% trichloroacetic acid. All lesions healed rapidly without any signs of discomfort. During a recheck examination 12 months later, the upper and lower left eyelids appeared morphologically normal, and there was no evidence of recurrence.

Clinical Relevance—Findings suggested that chemical ablation with trichloroacetic acid may be a useful treatment for apocrine hidrocystomas in cats.
Zinc intoxication in dogs: 19 cases (1991–2003)
Authors: Gurnee Carolyn M. , Drobatz Kenneth J.
Published: April 2007

Objective—To determine physical examination findings, clinicopathologic changes, and prognosis in dogs with zinc toxicosis.

Design—Retrospective case series.

Animals—19 dogs with zinc toxicosis.

Procedures—Medical records from 1991 through 2003 were searched for animals with a diagnosis of zinc toxicosis.Information concerning signalment, body weight, historical findings, initial owner complaints, physical examination findings, clinicopathologic findings, blood zinc concentrations, source of zinc, treatments given, duration of hospital stay, and outcome was collected.

Results—Records of 19 dogs with zinc toxicosis were reviewed.The most common historical findings were vomiting (n = 14) and pigmenturia (12).The most common clinicopatho logic findings were anemia (n = 19) and hyperbilirubinemia (12).Median age was 1.3 years, and median weight was 5.6 kg (12.3 lb). The prognosis was favorable, with 17 dogs surviving after a median hospital stay of 2 days.

Conclusions and Clinical Relevance—Hemolytic anemia as a result of zinc toxicosis appeared to affect young small-breed dogs more frequently than older large-breed dogs.The prognosis with treatment is good, and most affected dogs had a short hospital stay.
Factors associated with outcome following treatment of horses with septic tenosynovitis: 51 cases (1986–2003)
Authors: Wereszka Marta M. , White Nathaniel A. , Furr Martin O.
Published: April 2007

Objective—To identify factors associated with outcome (ie, survival and return to function) following treatment of horses with septic tenosynovitis.

Design—Retrospective case series.

Animals—51 horses with septic tenosynovitis.

Procedures—Information was obtained from medical records and through follow-up conversations with owners. Factors analyzed for an association with outcome included affected limb, etiology, duration of clinical signs prior to examination, presence of complications, primary treatment, secondary treatments, number of surgical procedures, and hospitalization time.

Results—Concurrent complications were identified in 41 (80%) horses. The primary treatment consisted of through-and-through lavage in 26 (51%) horses, tenoscopy in 20 (39%), and tenosynoviotomy combined with lavage in 5 (10%). Forty (78%) horses were discharged, and 37 (73%) survived at least 1 year after surgery; 21 of the 37 (57%) returned to their previous or a higher level of performance. Percentages of horses that survived 1 year after discharge and percentages that returned to their intended use did not vary significantly among treatments. Horses with tendon rupture or sepsis of an adjacent joint were significantly less likely to survive. Horses with tendon injury or pannus were significantly less likely to return to their intended use.

Conclusions and Clinical Relevance—Results suggested that various factors were associated with outcome in horses with septic tenosynovitis. However, surgical technique was not found to be associated with survival rate or rate of return to intended use.
Internal fixation of a femur fracture in an American bullfrog
Authors: Royal Lillian W. , Grafinger Michael S. , Lascelles B. Duncan X. , Lewbart Gregory A. , Christian Larry S.
Published: April 2007

Case Description—An adult male American bullfrog (Rana catesbeiana) was evaluated by the North Carolina State University College of Veterinary Medicine's Turtle Rescue Team following vehicular trauma.

Clinical Findings—A fracture of the left femur was suspected on examination and palpation of the hind limbs, but no other injuries or abnormalities were detected. While the bullfrog was sedated, whole-body radiographic views were obtained, which revealed a closed midshaft comminuted fracture of the left femur.

Treatment and Outcome—The fracture was repaired by use of an internal fixation technique that included Kirschner wires, a positive-profile pin secured along the femur with encircling sutures, and polymethylmethacrylate molded around the entire apparatus. There were no major complications during the postoperative rehabilitation period. One year after surgery, radiography revealed complete fracture healing and the bullfrog was released back into the wild.

Clinical Relevance—Presently, there are no widely accepted methods for fracture fixation in amphibians. Factors associated with their aquatic environment and lengthy fracture healing time must be addressed when planning fracture fixation strategies. In the bullfrog of this report, the applied internal fixation method provided effective long-term stabilization of the femur, allowed for normal movement, and enabled the bullfrog to be housed in an aquatic environment immediately after surgery.
Improved Synthesis of Pyrroles and IndolesviaLewis Acid‐Catalyzed Mukaiyama–Michael‐Type Addition/Heterocyclization of Enolsilyl Derivatives on 1,2‐Diaza‐1,3‐Butadienes. Role of the Catalyst in the Reaction Mechanism
Authors: Attanasi Orazio A. , Favi Gianfranco , Filippone Paolino , Lillini Samuele , Mantellini Fabio , Spinelli Domenico , Stenta Marco
Published: April 2007

The Mukaiyama–Michael‐type addition of various silyl ketene acetals or silyl enol ethers on some 1,2‐diaza‐1,3‐butadienes proceeds at room temperature in the presence of catalytic amounts of Lewis acid affording by heterocyclization 1‐aminopyrrol‐2‐ones and 1‐aminopyrroles, respectively. 1‐Aminoindoles have been also obtained by the same addition of 2‐(trimethylsilyloxy)‐1,3‐cyclohexadiene on some 1,2‐diaza‐1,3‐butadienes and subsequent aromatization. Mechanistic investigations indicate the coordination by Lewis acid of the enolsilyl derivative and its 1,4‐addition on the azo‐ene system of 1,2‐diaza‐1,3‐butadienes. The migration of the silyl group from a hydrazonic to an amidic nitrogen, its acidic cleavage and the final internal heterocyclization give the final products. Based on NMR studies andab initiocalculations, a plausible explanation for the migration of the silyl protecting group is presented.
Vanadium‐Catalyzed Selective Oxidation of Alcohols to Aldehydes and Ketones with tert‐Butyl Hydroperoxide
Authors: Rout Laxmidhar , Nath Pinku , Punniyamurthy Tharmalingam
Published: April 2007

The oxidation of alcohols to aldehydes and ketones has been described using silica‐supported vanadium(IV) oxide (V/SiO2, 1) in the presence of tert‐butyl hydroperoxide in tert‐butyl alcohol at ambient temperature with quantitative yields. The procedure is simple, efficient and environmentally benign.
Activation of Mononuclear Arene Ruthenium Complexes for Catalytic Propargylation Directly with Propargyl Alcohols
Authors: Bustelo Emilio , Dixneuf Pierre H.
Published: April 2007

Mononuclear complexes of the type [(p‐cymene)RuX(CO)(PR3)][OTf] (R=Ph, Cy; X=Cl, OTf) promote the direct catalytic propargylation of furan with propargyl alcohols. These precursors are generatedin situfrom [(p‐cymene)RuCl(OTf)(PR3)] by activation of the propargylic alcohol, leading to the carbonyl ligand formationviaallenylidene and alkenyl‐hydroxycarbene intermediates. The generation of the catalytically active species requires a short initial thermal activation to induce decoordination of thep‐cymene ligand. Thein situgenerated catalyst has been applied to catalytic transformations of alkynes and propargylic alcohols: propargylation of furans, propargyl ether synthesis from internal and terminal propargylic alcohols with propargyl, homopropargyl and allyl alcohols, selective dimerization of phenylacetylene intoE‐enyne, and propargyl alcohol rearrangement into α,β‐unsaturated aldehydes and ketonesviathe Meyer–Schuster rearrangement. The propargylation of propargylic alcohols containing internal CC bonds suggests an activationviathe Nicholas‐type intermediate, the metal‐stabilized propargyl cation.
The effect of consumer risk perceptions on the propensity to purchase genetically modified foods in Romania
Authors: Curtis Kynda R. , Moeltner Klaus
Published: April 2007

This study evaluates consumer purchase propensity for genetically modified (GM) food products in Romania, shedding light on consumer preferences in developing Eastern European nations. Results based on a bivariate probit model of purchase propensity for GM sunflower oil and table potatoes show that consumers in Romania are generally opposed to GM food consumption, similar to consumers in Western Europe, but contrary to consumers in many developing nations. Purchase probabilities carry across GM foods, indicating homogeneity in consumer risk perceptions. Additionally, income levels and risk perceptions are the primary drivers of purchase decisions, whereas positive or beneficiary product attributes (e.g., health, environmental, economic) are currently not considered by consumers. Negative consumer risk perceptions of GM goods in Romania will likely make the implementation of these crops for economic development purposes difficult. [EconLit Citations: Q18, D12, O12] © 2007 Wiley Periodicals, Inc. Agribusiness 23: 263–278, 2007.
HACCP implementation and economic optimality in turkey processing
Authors: Nganje William E. , Kaitibie Simeon , Sorin Alexander
Published: April 2007

Regulatory impact assessment suggests that Hazard Analysis and Critical Control Points (HACCP) is a cost‐effective food safety regulation that is highly beneficial to society. This study focuses on firm‐level costs and benefits from adoption of specific critical control points. A stochastic optimization framework is used to determine optimal testing and sampling strategies for Salmonella reduction in turkey processing. Results show that under The Food Safety Inspection Service (FSIS) mandated tolerance levels, processors need to designate no more than five critical control points, three more than what is included in the generic HACCP plan. Moves to tighten tolerances should be considered carefully because additional implementation costs tend to increase exponentially. [EconLit Citations: Q18, D81, C61] © 2007 Wiley Periodicals, Inc. Agribusiness 23: 211–228, 2007.
Nonlinear experimental design using Bayesian regularized neural networks
Authors: Coleman Matthew C , Block David E
Published: April 2007

Novel criteria for designing experiments for nonlinear processes are presented. These criteria improve on a previous methodology in that they can be used to suggest a batch of new experiments to perform (as opposed to a single new experiment) and are also optimized for discovering improved optima of the system response. This is accomplished by using information theoretic criterion, which also heuristically penalize experiments that are likely to result in low (nonoptimal) results. While the methods may be applied to any type of nonlinear‐nonparametric model (radial basis functions and generalized linear regression), they are here exclusively considered in conjunction with Bayesian regularized feedforward neural networks. A focus on the application of rapid process development, and how to use repeated experiments to optimize the training procedures of Bayesian regularized neural networks is shown. The presented methods are applied to three case studies. The first two case studies involve simulations of one and two‐dimensional (2‐D) nonlinear regression problems. The third case study involves real historical data from bench‐scale fermentations generated in our laboratory. It is shown that using the presented criteria to design new experiments can greatly increase a feedforward neural network's ability to predict global optima. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Access to data on chemical composition of products used in auto repair and body shops
Authors: Karstadt Myra , Bobal Renee
Published: April 2007

Some information on chemical composition of products used in the workplace can be obtained by requesting composition data from product marketers.

Workers in auto repair and body shops identified 253 products used in their shops. Full disclosure of composition was obtained for approximately 20% of the 174 products marketed by companies which answered our letters. Composition was partially disclosed for approximately 40% of the products, and about 10% of the product formulations were claimed to be trade secret or confidential.

The study reported in this paper was carried out in New York State in 1980, before the effective date of the New York State right‐to‐know law. The results of this study can be used as a benchmark to judge the effectiveness of worker right‐to‐know laws and product labeling regulations.
A multivariate statistical method for the establishment of maximum allowable exposure to toxic materials in the workplace
Authors: Goldstein Richard B. , Silverberg Joel S. , Martin Horace F.
Published: April 2007

A model has been developed for setting standard limiting concentrations for toxic substances in the body fluid or tissues of industrial workers. The method is very flexible, and allows the use of either univariate or multivariate data, and of classification schemes, which are either supervised, unsupervised, or partially supervised. An index of subclinical biological damage is derived which is used to determine an optimal limiting exposure level. The model is applied to the particular case of selecting a maximum allowable concentration of blood lead in workers in industrial settings where lead toxicity is a danger.
Mortality among a sample of chemical company employees
Authors: Bond Gregory G. , Reeve Gordon R. , Gerald Ott M. , Waxweiler Richard J.
Published: April 2007

A general mortality survey was done on a 5% random‐start systematic sample (N = 1,666) of present and former white male employees of a Texas chemical plant. The purpose was to determine whether there were any unusual patterns of cause‐specific mortality that would require further research with case‐control studies. Mortality risks were examined by duration of employment and year of hire as surrogates for more specific exposure data. Among all employees in the sample, there was significant excess mortality due to All Cancer, Ill‐Defined Conditions, and All External Causes of Death, and a significant deficit from All Circulatory Diseases. The excess mortality from All Cancer was primarily attributable to excess cancers of the kidney, lung, and pancreas. The excesses for lung and kidney cancer were statistically significant. Those employed for 1 year or more experienced significantly lower mortality from All Causes than those employed for less than 1 year.
Epidemiologic and immunologic studies in processors of the king crab
Authors: Orford Robert R. , Wilson John T.
Published: April 2007

Following the report of ten cases of respiratory illness in processors of frozen king crab, we investigated the conditions of work and the pulmonary and immunologic status of the workers in three crab‐processing and one fish‐packing (control) plant. Pulmonary function was measured before and after work, and skin tests were performed in subgroups matched for age, sex, and duration of current employment. The antibody response to king crab antigens was examined in sera from the subgroups and another (unrelated) control group. Extracts of crab meat, shell, and processing dust were used for skin testing and precipitin detection. FEV1, FVC, and MEFR decreased during the day in two crab processors, and precipitins were evident in sera from nine, but findings were normal in the fish packers. Crab meat elicited the strongest response, with multiple precipitin bands in some cases. Control sera showed no reaction. There was correlation between serology, results of skin tests, and symptoms. It is concluded that the inhalation of aerosolized crab antigen(s) may cause respiratory symptoms and can cause immunologic effects similar to those caused by other occupational respiratory allergens. We recommend preplacement and periodic medical examination of workers in crab‐processing plants, improved ventilation in processing areas, and programs to discourage smoking.
Proportionate mortality study of workers in the garment industry exposed to formaldehyde
Authors: Stayner Leslie , Smith Alexander B. , Reeve Gordon , Blade Leo , Elliott Larry , Keenlyside Richard , Halperin William
Published: April 2007

In order to evaluate the human carcinogenicity of formaldehyde, we conducted a proportionate mortality study of garment workers engaged in the production of shirts from formaldehyde‐treated cloth. This study included three plants, and was based upon 256 deaths identified from a death‐benefit insurance fund. No deaths due to nasal cancer were observed, and the mortality from respiratory cancer (11 cases, PMR = 95) was slightly less than expected. Statistically significant (p < .05) elevations in proportionate mortality were observed for malignant neoplasms of the “buccal cavity” (three cases, PMR = 750), for “biliary passages and liver” (four cases, PMR = 313) and for “other lymphatic and hematopoietic sites” (four cases, PMR = 400). A proportionate cancer mortality (PCMR) analysis also was conducted, and cancer of the “buccal cavity” (three cases, PCMR = 682), and other “lymphatic and hematopoietic sites” (four cases, PCMR = 342) were still significantly elevated. The observed excesses in cancer mortality were primarily experienced by white females, who made up the major portion of the workforce, and workers with more than 10 years of latency and duration of exposure, a criterion for inclusion for most workers in the study group. The neoplasms observed were not equally distributed among the three facilities included in the study. Because of the small number of deaths involved and the lack of consistency with other studies, we believe that these findings should be viewed cautiously, pending the outcome of more definitive studies.
Mortality among rubber workers: X. Reclaim workers
Authors: Delzell Elizabeth , Monson Richard R.
Published: April 2007

This study evaluated the mortality experience of 1,352 white and 438 nonwhite men who worked in the rubber‐reclaiming division of a large rubber manufacturing company. In comparisons of mortality of white reclaim workers with that of nonreclaim workers rate ratios were 2.7 for esophageal cancer (six observed deaths among reclaim workers), 2.1 for bladder cancer (seven observed deaths), and 4.5 for multiple myeloma (six observed deaths). The excess of bladder cancer among white reclaim workers may be associated with their employment in other high‐risk areas of the plant, whereas no such explanation was found for the excesses of esophageal cancer and multiple myeloma. Overall, the lung cancer mortality rate of white reclaim workers was similar to the rate of US white males and other white rubber workers. There was a 50% excess of lung cancer deaths among nonwhite reclaim workers compared with other nonwhite rubber workers. However, this observation is based on small numbers, and no firm conclusions can be reached about the risk of lung cancer associated with reclaim operations in this group of rubber workers.
Asbestos disease in sheet metal workers: The results of a proportional mortality analysis
Authors: Zoloth Stephen , Michaels David
Published: April 2007

The results of a proportional mortality analysis of a cohort of sheet metal workers who have only intermittent exposure to asbestos demonstrates a significant excess of cancer at the three sites most frequently associated with asbestos: lung, colon and rectum, and the mesothelium. No excess nonmalignant respiratory disease was detected. These data strongly suggest that significant asbestos‐related disease is present in populations with secondary exposure to asbestos and emphasize the importance of considering possible asbestos‐related disease when treating patients with a history of employment in the construction industry.
Percutaneous penetration of benzene in hairless mice: An estimate of dermal absorption during tire‐building operations
Authors: Susten Allan S. , Dames Barbara L. , Burg Jeanne R. , Niemeier Richard W.
Published: April 2007

Repeated skin contact with solvents containing as much as 0.5% benzene is common in workers building regular bias passenger tires. To estimate the amount of benzene absorbed through the skin of these workers, a series of in vivo studies was conducted in hairless mice. Percutaneous absorption, following single dermal applications of 14C‐benzene contained in rubber solvent at a concentration of 0.5% (v/v), was calculated directly from the sums of radioactivity found in excreta, expired breath, and the carcass. Data from the study, together with observations made during tire‐building operations, suggest that a worker could absorb 4–8 mg of benzene daily through the skin. This compares to 14 mg per day via inhalation at the NIOSH recommended standard of 1 ppm. Thus dermal absorption could contribute from 20–40% of the total benzene dose of these workers.
A bayesian approach for predicting judged hearing disability
Authors: Phaneuf Richard , Hétu Raymond , Hanley James A.
Published: April 2007

A method of determining the cutoff point for an administrative decision to award compensation is proposed. To construct the predictive system a Bayesian approach and discriminant analysis were employed. Judged hearing disability was used as the criterion with audiometric scores as the determining variables. The common law doctrine of the balance of probability was used as the criterion, namely the 50th centile, on which to propose a cutoff point. The highest precision in predicting judged hearing disability was obtained with an average audiometric score at 1,000, 2,000, 3,000, 4,000 Hz in the worse ear. Assuming that judged hearing disability is a valid predictor of handicap, the cutoff point based on the balance of probability (50th centile) was obtained at 25 dB. The study also confirmed results from previous studies: (1) hearing sensitivity in frequencies higher than 2,000 Hz is required to predict hearing disability and handicap, (2) judged hearing disability is better correlated with hearing sensitivity in the worst ear, and (3) the audiometric cutoff point for a medical legal definition of impairment should be lower than what certain technical groups have proposed in the past.
Malignancies due to occupational exposure to benzene
Authors: Aksoy Muzaffer
Published: April 2007

There is no doubt about the leukemogenic effect of benzene in man. The evidence is as follows: (1) The incidence of leukemia in shoeworkers exposed to benzene in a period of 8 years in Istanbul was 13.6/100,000, which is significantly higher than that for leukemia in the general population. (2) Following the phase‐out of benzene in Istanbul, the number of leukemic workers decreased and none were reported in the subsequent 3 years. (3) The development of leukemia in pancytopenic patients with benzene exposure was observed in 13 out of 51 patients. (4) The differences in the distribution of the types of leukemia in individuals exposed and in nonexposed groups were as follows: acute leukemia 96.1% in the former group, and 46% in the latter group. The high percentages of acute erythroleukemia and preleukemia were other interesting findings in the exposed group. (5) Two cases of leukemia were observed in a 6‐year period at a tire cord manufacturing plant with 550 workers. At one location in the plant the concentration of benzene measured by gas chromatography was nearly 110 ppm. Additionally, we have studied 12 cases of malignant lymphoma, four cases of multiple myeloma, and six cases of lung cancer, all of whom were chronically exposed to benzene. The possible role of benzene in the etiology of these malignancies is discussed.
Projections of leukemia risk associated with occupational exposure to benzene
Authors: Infante Peter F. , White Mary C.
Published: April 2007

In 1982, White et al published an assessment of quantitative leukemia risk associated with lifetime occupational exposure to benzene. At about the same time, IARC (1982) published estimates of quantitative cancer risk associated with industrial chemicals. Benzene was one of the two chemicals selected by IARC for its risk estimation. This paper presents a summary of these assessments along with new study results demonstrating adverse effects on bone marrow and peripheral blood cells as a result of low‐level benzene exposure.

Mathematical extrapolations based on epidemiologic studies are consistent with a finding of significant risk of dying from leukemia under the current occupational permissible exposure limit of 10 ppm. Although a significant reduction of risk could be expected to be achieved by reducing exposure to 1 ppm, a significant risk may still remain. The uncertainty of the dose‐response projections rests on the underlying estimates of relative risk of death from leukemia, the estimates of benzene exposure (dose), and the appropriateness of the mathematical model.

Recent findings in experimental animals demonstrate chromosomal damage to bone marrow cells, significant depression of the bone marrow, and disturbances of immune system function as a result of less than 1 week of exposure to the current permissible benzene exposure limit of 10 ppm. This was the lowest dose tested. These experimental findings provide further evidence of a potentially significant risk of bone marrow proliferative cancer (leukemia) as a result of low‐dose benzene exposure.
Experimental studies on benzene carcinogenicity at the bologna institute of oncology: Current results and ongoing research
Authors: Maltoni Cesare , Conti Barbara , Cotti Giuliano , Belpoggi Fiorella
Published: April 2007

In 1977 Maltoni and Scarnato were the first to demonstrate that benzene is an experimental carcinogen in rats. With that and other experiments, Maltoni et al have shown that benzene administered by ingestion (stomach tube) or inhalation is a multipotential carcinogen in rats (of two different strains) and mice and produces a variety of tumors, namely: Zymbal gland carcinomas, oral and nasal cavity carcinomas, skin carcinomas, acanthomas, dysplasias and carcinomas of forestomach, mammary malignant tumors, hepatomas, liver angiosarcomas, hemolymphoreticular neoplasias, and pulmonary tumors. The incidence of Zymbal gland carcinomas and carcinomas of the oral and nasal cavitities is affected by the length of treatment by inhalation and by the age of animals. However, the available epidemiological and experimental data at present do not provide precise information on the risk of doses around or below 10 ppm. Long‐term carcinogenicity bioassays at 50, 25, 10, 5 and 1 ppm may be helpful for scientific risk assessment. In addition, these experiments have shown that toluene, xylene, and ethylbenzene, at high concentrations, cause an increase in the number of total malignant tumors.
Benzene hematotoxicity and leukemogenesis
Authors: Cronkite Eugene P. , Drew R. T. , Inoue T. , Bullis J. E.
Published: April 2007

Eight‐to‐twelve‐week‐old male and female C57B1/6 BNL mice were exposed to air or benzene vapor in air at a concentration of 10, 25, 100, 300, or 400 ppm. Benzene at concentrations of 100 ppm or higher for 10 exposures of 6 hours per day 5 days a week produced a reduction in bone marrow cellularity and the number of pluripotent stem cells in the bone marrow. The fraction of stem cells in DNA synthesis was also increased. Exposure to 300 ppm 6 hours a day 5 days a week for 2, 4, 8, and 16 weeks produced a diminution in the stem cell levels in bone marrow which returned to those of controls 2 weeks after benzene exposure for 2 and 4 weeks, 16 weeks after exposure for 8 weeks, and to 92% of controls 25 weeks after 16 weeks of exposure. There was a more rapid return of blood lymphocytes to the control level. Mice exposed to 300 ppm for 6 hours/day, 5 days per week for 16 weeks began dying at 330 days of age, whereas no deaths were observed in sham‐exposed mice until 440 days of age. The benzeneexposed mice died in two waves: the first was from 330‐390 days of age, with a second wave commencing at 570 days of age. The first wave of mortality was due primarily to thymic lymphomata. The second wave was due to a mixture of nonthymic lymphomata and solid tumors.
Benzene as a leukemogenic and carcinogenic agent
Authors: Aksoy Muzaffer
Published: April 2007

Today there seems to be sufficient data to incriminate benzene as a potent carcinogenic agent causing leukemia, malignant lymphoma, multiple myeloma and lung cancer, as well as numerous disorders of the bone marrow depression. Other factors (such as genetic and individual susceptibility) may have a role in the development of these different types of malignancies and hematologic disorders. In this paper, data concerning all these problems are presented and discussed.
Elimination kinetics of blood lead in workers with chronic lead intoxication
Authors: Hryhorczuk Daniel O. , Rabinowitz Michael B. , Hessl Stephen M. , Hoffman Douglas , Hogan Mary M. , Mallin Katherine , Finch Hollister , Orris Peter , Berman Eleanor
Published: April 2007

Blood lead elimination half‐lives were determined for 65 patients with occupational chronic lead intoxication who were removed from exposure, treated with intravenous EDTA, and followed for periods of up to 2,419 days. The median overall blood lead elimination half‐life was 619 days in patients with normal renal function and 1,907 days in patients with renal impairment. Slow‐phase elimination half‐lives in patients followed for longer than 5 years ranged from 1,658 to 7,189 days. Blood lead concentrations declined during periods of chelation with a mean half‐life of 7 days and rebounded to near prechelation concentrations following termination of chelation with a mean doubling time of 27 days. The overall blood lead elimination half‐life was positively associated with length of follow‐up (p < 0.001), age (p = 0.04), and duration of exposure (p = 0.02), but was not associated with the initial blood lead concentration following cessation of exposure or the total amount of EDTA received.
The middling tendency in reading chest films for pneumoconiosis: An important source of bias and variability
Authors: Hessel Patrick A.
Published: April 2007

The tendency for readers of chest films of the pneumoconioses to place films in the middle of the International Labour Office (ILO) categories of profusion (eg, 1/1, 2/2) was described by Morgan et al [1974], who saw this tendency as a possible source of bias. The present study reexamines the middling tendency in relation to bias and variability by comparing duplicate readings of chest films for pneumoconiosis. Readings of trained lay persons were compared to professional readings of the same films and readings of professional readers were compared with each other.

Reasons for the middling tendency, which include the use of standard middle films and the instructions given to users of the classification, are suggested and possible solutions are proposed.
A proportional mortality study of the acting profession
Authors: Depue Robert H. , Kagey Betsy T. , Heid Marian F.
Published: April 2007

Proportional mortality of actors and actresses was studied because cancers of many sites have been linked to hair dyes and cosmetics of which actors have been frequent users. Death records (1950–1978) for 2,618 white male and 838 white female members of Actors Equity and the Screen Actors Guild were compared with the U.S. mortality rates. Among males, significantly elevated proportional mortality ratios (MPR) were found for suicide (1.58), cirrhosis of the liver (1.99), all malignancies (1.15), and cancers of the colon/rectum (1.32), pancreas (1.51), and testes (2.37). Colon/rectum and pancreas cancers were not significantly elevated by proportional cancer mortality. Among females, significantly elevated PMRs were found for suicide (2.02) and lung cancer (2.20). Suicide in either sex was much more common in California than in New York. The elevated lung cancer in females was confined to Equity members. No elevations were found for cancers that have been related to hair dye or cosmetic use—ie, breast, ovary, bladder, leukemia, and lymphomas.