bluuebunny/crossref_metadata_2025 huggingface dataset:
Transverse extension of partons in the proton probed by DVCS at COMPASS
Authors: Sandacz Andrzej
Published: January 2020

We present the first result on exclusive single-photon muoproduction on the proton in the range of intermediate values of the Bjorken variable xBj

, which was recently published by COMPASS collaboration. The measurements were performed using 160GeV/c polarised μ
+ and μ
− beams of the CERN SPS scattering off a liquid hydrogen target. We determine the dependence of the average of the measured μ
+ and μ
− cross sections for deeply virtual Compton scattering on the squared four-momentum transfer t from the initial to the final proton. The slope B of the t-dependence is fitted with a single exponential function, which yields

B
=

(

4.3
±

0.6

stat

+

0.1

−

0.3

|

sys

)

(

GeV
/
c

)

−
2

. This result can be converted into an average transverse extension of partons in the proton,

〈

r
⊥
2

〉

=

(

0.58
±

0.04

stat

+

0.01

−

0.02

|

sys

)

. For this measurement, the average virtuality of the photon mediating the interaction is ⟨Q
2⟩ = 1.8 (GeV/c)2 and the average value of the Bjorken variable is ⟨xBj

⟩ = 0.056. We also compare COMPASS result to earlier estimates at very small xBj

from HERA.
Ulrich bundles on Brauer–Severi varieties
Authors: Novaković Saša
Published: January 2020

We prove the existence of Ulrich bundles on any Brauer–Severi variety. In some cases, the minimal possible rank of the obtained Ulrich bundles equals the period of the Brauer–Severi variety. Moreover, we find a formula for the rank of an Ulrich bundle involving the period of the considered Brauer–Severi variety

X
X

, at least if

d
i
m

(
X
)
=
p
−
1

\mathrm {dim}(X)=p-1

for an odd prime

p
p

. This formula implies that the rank of any Ulrich bundle on such a Brauer–Severi variety

X
X

must be a multiple of the period.
Factorization of symplectic matrices into elementary factors
Authors: Ivarsson Björn , Kutzschebauch Frank , Løw Erik
Published: January 2020

We prove that a symplectic matrix with entries in a ring with Bass stable rank one can be factored as a product of elementary symplectic matrices. This also holds for null-homotopic symplectic matrices with entries in a Banach algebra or in the ring of complex valued continuous functions on a finite dimensional normal topological space.
A new asymptotic expansion of a ratio of two gamma functions and complete monotonicity for its remainder
Authors: Yang Zhen-Hang , Tian Jing-Feng , Ha Ming-Hu
Published: January 2020

In this paper, we establish a new asymptotic expansion of a ratio of two gamma functions, that is, as

x
→
∞

x\rightarrow \infty

,
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="left-bracket StartFraction normal upper Gamma left-parenthesis x plus u right-parenthesis Over normal upper Gamma left-parenthesis x plus v right-parenthesis EndFraction right-bracket Superscript 1 slash left-parenthesis u minus v right-parenthesis Baseline tilde left-parenthesis x plus sigma right-parenthesis exp left-bracket sigma-summation Underscript k equals 1 Overscript m Endscripts StartFraction upper B Subscript 2 n plus 1 Baseline left-parenthesis rho right-parenthesis Over w n left-parenthesis 2 n plus 1 right-parenthesis EndFraction left-parenthesis x plus sigma right-parenthesis Superscript minus 2 k Baseline plus upper R Subscript m Baseline left-parenthesis x semicolon u comma v right-parenthesis right-bracket comma">

[

Γ

(
x
+
u
)

Γ

(
x
+
v
)

]

1

/

(
u
−
v
)

∼

(
x
+
σ
)

exp
⁡

[

∑

k
=
1

m

B

2
n
+
1

(
ρ
)

w
n

(
2
n
+
1
)

(
x

+

σ
)

−
2
k

+

R

m

(
x
;
u
,
v
)

]

,

\begin{equation*} \left [ \frac {\Gamma \left ( x+u\right ) }{\Gamma \left ( x+v\right ) }\right ] ^{1/\left ( u-v\right ) }\thicksim \left ( x+\sigma \right ) \exp \left [ \sum _{k=1}^{m}\frac {B_{2n+1}\left ( \rho \right ) }{wn\left ( 2n+1\right ) }\left ( x\!+\!\sigma \right ) ^{-2k}\!+\!R_{m}\left ( x;u,v\right ) \right ] , \end{equation*}

where

u
,
v
∈

R

u,v\in \mathbb {R}

with

w
=
u
−
v
≠
0

w=u-v\neq 0

and

ρ
=

(
1
−
w
)

/

2

\rho =\left ( 1-w\right ) /2

,

σ
=

(
u
+
v
−
1
)

/

2

\sigma =\left ( u+v-1\right ) /2

,

B

2
n
+
1

(
ρ
)

B_{2n+1}\left ( \rho \right )

are the Bernoulli polynomials. We also prove that the function

x
↦

(
−
1
)

m

R

m

(
x
;
u
,
v
)

x\mapsto \left ( -1\right ) ^{m}R_{m}\left ( x;u,v\right )

for

m
∈

N

m\in \mathbb {N}

is completely monotonic on

(
−
σ
,
∞
)

\left ( -\sigma ,\infty \right )

if

|
u
−
v
|

>
1

\left \vert u-v\right \vert >1

, which yields an explicit bound for

|

R

m

(
x
;
u
,
v
)

|

\left \vert R_{m}\left ( x;u,v\right ) \right \vert

and some new inequalities.
Active manipulation of exterior electromagnetic fields by using surface sources
Authors: Onofrei Daniel , Platt Eric , Egarguin Neil
Published: January 2020

In this paper, we establish a scheme for the active manipulation of electromagnetic fields in prescribed exterior regions using a surface source. We prove the existence of the necessary surface current (electric or magnetic) on a single source to approximate prescribed electromagnetic fields on given regions of space (bounded or possibly the far field). We provide two constructive schemes for the computation of the required surface currents: our first strategy makes use of the Debye representation results for the electromagnetic field and builds up on previous control results for scalar fields discussed in [J. Integral Equations Appl. 26 (2014), pp. 553–579]; the second strategy we propose makes use of integral electromagnetic representation results and follows theoretically from the first. We provide theoretical validation for both computational schemes and present supporting numerical simulations for the first strategy in several applied scenarios.
BioSeqZip: a collapser of NGS redundant reads for the optimization of sequence analysis
Authors: Urgese Gianvito , Parisi Emanuele , Scicolone Orazio , Di Cataldo Santa , Ficarra Elisa
Published: January 2020

Motivation

High-throughput next-generation sequencing can generate huge sequence files, whose analysis requires alignment algorithms that are typically very demanding in terms of memory and computational resources. This is a significant issue, especially for machines with limited hardware capabilities. As the redundancy of the sequences typically increases with coverage, collapsing such files into compact sets of non-redundant reads has the 2-fold advantage of reducing file size and speeding-up the alignment, avoiding to map the same sequence multiple times.

Method

BioSeqZip generates compact and sorted lists of alignment-ready non-redundant sequences, keeping track of their occurrences in the raw files as well as of their quality score information. By exploiting a memory-constrained external sorting algorithm, it can be executed on either single- or multi-sample datasets even on computers with medium computational capabilities. On request, it can even re-expand the compacted files to their original state.

Results

Our extensive experiments on RNA-Seq data show that BioSeqZip considerably brings down the computational costs of a standard sequence analysis pipeline, with particular benefits for the alignment procedures that typically have the highest requirements in terms of memory and execution time. In our tests, BioSeqZip was able to compact 2.7 billion of reads into 963 million of unique tags reducing the size of sequence files up to 70% and speeding-up the alignment by 50% at least.

Availability and implementation

BioSeqZip is available at https://github.com/bioinformatics-polito/BioSeqZip.

Supplementary information

Supplementary data are available at Bioinformatics online.
Bivartect: accurate and memory-saving breakpoint detection by direct read comparison
Authors: Shimmura Keisuke , Kato Yuki , Kawahara Yukio
Published: January 2020

Motivation

Genetic variant calling with high-throughput sequencing data has been recognized as a useful tool for better understanding of disease mechanism and detection of potential off-target sites in genome editing. Since most of the variant calling algorithms rely on initial mapping onto a reference genome and tend to predict many variant candidates, variant calling remains challenging in terms of predicting variants with low false positives.

Results

Here we present Bivartect, a simple yet versatile variant caller based on direct comparison of short sequence reads between normal and mutated samples. Bivartect can detect not only single nucleotide variants but also insertions/deletions, inversions and their complexes. Bivartect achieves high predictive performance with an elaborate memory-saving mechanism, which allows Bivartect to run on a computer with a single node for analyzing small omics data. Tests with simulated benchmark and real genome-editing data indicate that Bivartect was comparable to state-of-the-art variant callers in positive predictive value for detection of single nucleotide variants, even though it yielded a substantially small number of candidates. These results suggest that Bivartect, a reference-free approach, will contribute to the identification of germline mutations as well as off-target sites introduced during genome editing with high accuracy.

Availability and implementation

Bivartect is implemented in C++ and available along with in silico simulated data at https://github.com/ykat0/bivartect.

Supplementary information

Supplementary data are available at Bioinformatics online.
Chronic testicular Chlamydia muridarum infection impairs mouse fertility and offspring development†
Authors: Bryan Emily R , Redgrove Kate A , Mooney Alison R , Mihalas Bettina P , Sutherland Jessie M , Carey Alison J , Armitage Charles W , Trim Logan K , Kollipara Avinash , Mulvey Peter B M , Palframan Ella , Trollope Gemma , Bogoevski Kristofor , McLachlan Robert , McLaughlin Eileen A , Beagley Kenneth W
Published: January 2020

With approximately 131 million new genital tract infections occurring each year, Chlamydia is the most common sexually transmitted bacterial pathogen worldwide. Male and female infections occur at similar rates and both cause serious pathological sequelae. Despite this, the impact of chlamydial infection on male fertility has long been debated, and the effects of paternal chlamydial infection on offspring development are unknown. Using a male mouse chronic infection model, we show that chlamydial infection persists in the testes, adversely affecting the testicular environment. Infection increased leukocyte infiltration, disrupted the blood:testis barrier and reduced spermiogenic cell numbers and seminiferous tubule volume. Sperm from infected mice had decreased motility, increased abnormal morphology, decreased zona-binding capacity, and increased DNA damage. Serum anti-sperm antibodies were also increased. When both acutely and chronically infected male mice were bred with healthy female mice, 16.7% of pups displayed developmental abnormalities. Female offspring of chronically infected sires had smaller reproductive tracts than offspring of noninfected sires. The male pups of infected sires displayed delayed testicular development, with abnormalities in sperm vitality, motility, and sperm-oocyte binding evident at sexual maturity. These data suggest that chronic testicular Chlamydia infection can contribute to male infertility, which may have an intergenerational impact on sperm quality.
Protocoled thrombolytic therapy for frostbite improves phalangeal salvage rates
Authors: Paine Rosemary Elizabeth , Turner Elizabeth Noel , Kloda Daniel , Falank Carolyne , Chung Bruce , Carter Damien Wilson
Published: January 2020

Background

Frostbite is a cold injury that has the potential to cause considerable morbidity and long-term disability. Despite the complexity of these patients, diagnostic and treatment practices lack standardization. Thrombolytic therapy has emerged as a promising treatment modality, demonstrating impressive digit salvage rates. We review our experience with thrombolytic therapy for severe upper extremity frostbite.

Methods

Retrospective data on all frostbite patients evaluated at our institution from December 2017 to March 2018 was collected. A subgroup of patients with severe frostbite treated with intra-arterial thrombolytic therapy (IATT) were analysed.

Results

Of the 17 frostbite patients treated at our institution, 14 (82%) were male and the median age was 31 (range: 19–73). Substance misuse was involved in a majority of the cases (58.8%). Five (29.4%) patients with severe frostbite met inclusion criteria for IATT and the remaining patients were treated conservatively. Angiography demonstrated a 74.5% improvement in perfusion after tissue plasminogen activator thrombolysis. When comparing phalanges at risk on initial angiography to phalanges undergoing amputation, the phalangeal salvage rate was 83.3% and the digit salvage rate was 80%. Complications associated with IATT included groin hematoma, pseudoaneurysm and retroperitoneal hematoma.

Conclusions

Thrombolytic therapy has the potential to greatly improve limb salvage and functional recovery after severe frostbite when treated at an institution that can offer comprehensive, protocoled thrombolytic therapy. A multi-center prospective study is warranted to elucidate the optimal treatment strategy in severe frostbite.
Colorimetric Determination of Blood Arginase
Authors: Friedman Max M , Becker Edythe
Published: January 2020

A colorimetric procedure for blood arginase has been described, based on hemolyzing the red blood cells with saponin and determining the urea formed by action of the enzyme on an arginine substrate.

The range of blood arginase in a series of normal human subjects has been presented.
Cross-Contaminator Exclusion Test for Dry-Ashing Determination of Protein-Bound Iodine
Authors: Samson Mayer , Brown Herman , Eichen Seymour
Published: January 2020

A simple qualitative test for iodine in blood serum has been described. It is designed to detect sera which are potential cross-contaminators in dry-ashing PBI procedures. One drop of serum is used. Added operating time in a PBI series of 20-40 determinations is not over 30 minutes.
A Note on Quantitative Urobilinogen Determinations
Authors: Balikov Bernard
Published: January 2020

In the article, "A Note on Quantitative Urobilinogen Determinations", by Bernard Balikov, Vol. 1, 264 (August 1955), the abscissa label of Fig. 1, page 265, should read "2% glacial acetic acid assumed to yield 100% recovery."
Studies of Body Water and Water Turnover Determined with Deuterium Oxide Added to Food
Authors: Gaebler O H , Choitz H C
Published: January 2020

In 5 dogs which ingested 25 or 50 ml. of D2O with one daily meal, maximal plasma concentrations of tracer were reached in 12-24 hr. The disappearance rate during 14 days was exponential, confirming studies of others in humans. Water turnover, calculated from values obtained for body water and the disappearance rates, agreed well with total water intake, which included water taken as such and that derived by oxidation. Water intake per square meter of surface area varied widely; there was also no constant relationship between either total turnover or extrarenal loss and caloric intake. Since animals were maintained at nearly constant weights for long periods, caloric intake and total heat production were presumably equivalent. Thus the possibility of estimating total heat production from water turnover or extrarenal loss was not promising, but the validity of body water and turnover estimations was well supported. Average value for body water was 60.6% of body weight, with a range of 56.1% to 66.6%.
A Simple Serum Iron Method Using the New Sensitive Chromogen Tripyridyl-s-triazine
Authors: Fischer David S , Price David C
Published: January 2020

A simple, specific and reproducible serum iron method is described using the recently synthesized and highly sensitive chromogen, tripyridyl-S-triazine. The absorbance of this chromogen is compared to other iron reagents. Procedural modifications are given for using the Ramsay iron-binding capacity method with this serum iron procedure. The normal values found agree with most of those in the literature which has been reviewed.
Seroflocculating Steroids
Authors: Chang Frederic C , Blickenstaff Robert T
Published: January 2020

A screening test used in the study of steroids having seroflocculating activity is described. Twenty compounds previously screened and assigned to activity classes were rescreened using the same set of sera. Results duplicated previous screening reasonably well, and indicated that the method is practical and reproducible.
Multiple Automatic Sequential Analysis
Authors: Skeggs Leonard T , Hochstrasser Harry
Published: January 2020

A multiple automatic analyzer has been constructed which determines albumin, total protein, chloride, carbon dioxide, sodium, potassium, glucose, and urea nitrogen. The results for each of these 8 determinations are obtained in sequence for an individual sample and are recorded on a single sheet of paper. The entire system is calibrated by means of a standard solution containing all 8 of the components under test. Results appear on the record in a directly readable and immediately usable form. The actual record is used as the laboratory report sent to the requesting physician.
A Shortened Screening Test for Catecholamines
Authors: Ettman S L , Gordon Herschel W
Published: January 2020

The procedure described employs aluminum oxide filter paper disks to shorten the time and increase the efficiency of the catecholamine screening test. There is less opportunity for loss of catecholamines during adsorption, transfer, or elution.
Interference of Thiouracil in the Ferric Chloride-Sulfuric Acid Cholesterol Reaction
Authors: Rice Eugene W
Published: January 2020

Thiouracil, previously recommended as a preservative to be added to serum for butanol-extractable iodine determinations, inhibits the ferric chloride-sulfuric acid color reaction for cholesterol. The color inhibition may be eliminated by shaking the serum for about 5 min. with solid silver iodate prior to cholesterol analysis.
Spectrophotometric Determination of Magnesium in Blood Serum Using Magon
Authors: Burcar Patricia J , Boyle Albert J , Mosher Robert E
Published: January 2020

A spectrophotometric method for the determination of serum magnesium using Magon, 1-azo-2-hydroxy-3- (2,4-dimethylcarboxanilido) naphthalene- 1’- (2-hydroxybenzene), is presented. The serum is prepared by a nitric-perchloric acid digestion. Interfering phosphate is removed as aluminum phosphate. The colored complex is developed at pH 11.2 in an alcoholic medium and read at 505 mµ.
Preservation of Blood Ammonia by Rapid Freezing-A Method for Delayed Determinations
Authors: Orloff Marshall J , Stevens Clarence O
Published: January 2020

A method is described for preservation of blood for delayed determinations of ammonia by rapid freezing of the samples in a dry ice and acetone solution followed by storage of the specimens in the frozen state. The method was evaluated by first establishing the reproducibility of the chemical method used for blood ammonia analysis in 714 consecutive samples of dog blood which were analyzed in duplicate, and then determining whether freezing caused greater changes in ammonia concentration than one would expect knowing the reproducibility of the chemical method. Studies in 200 samples of dog blood with ammonia levels of 16 to 2904 µg./100 ml., each of which was analyzed immediately and after 24 hr. of freezing, showed that freezing and storage for 24 hr. did not significantly affect the blood ammonia content. Studies of 22 samples of frozen dog blood with ammonia levels of 11 to 2624 µg/100 ml., parts of each of which were analyzed daily for 5 consecutive days, showed that storage in the frozen state for up to 72 hr. had no significant effect on the ammonia concentration, but that storage for 96 hr. or longer resulted in increases in blood ammonia beyond acceptable limits. It is concluded that accurate delayed measurements of blood ammonia may be accomplished by rapid freezing of the blood immediately after shedding, and storage of the frozen samples for up to 72 hr.
Urea Synthesis by Hemic Cells
Authors: Moore W Tabb , Rodarte Joseph , Smith Lloyd H
Published: January 2020

A method for measuring urea production by isolated erythrocytes and leucocytes under physiologic conditions is described. Erythrocytes from 10 normal subjects formed an average of 82.5 mµmoles urea/ml. packed cells/hr. Leucocytes formed 7.4 mµmoles urea/108 cells/hr. By extrapolation, total urea synthesis by circulating erythrocytes would be approximately 270 mg./day and by the granulocyte pool approximately 5 mg./day. The total contribution of circulating hemic cells to over-all urea synthesis approximates 1 to 3% on an average protein diet. Six patients with cystinuria were also studied. No defect in urea synthesis, as a reflection of impaired arginine transport, could be detected in their blood cells with the conditions employed.
A Quantitative Assay for Urinary Porphobilinogen
Authors: Moore Donald J , Labbe Robert F
Published: January 2020

A procedure has been developed for the rapid, quantitative determination of urinary porphobilinogen. Interfering substances are removed by selectively adsorbing the porphobilinogen with an ion-exchange resin using a batch method. After acid elution of the porphobilinogen, Ehrlich's reagent is added to produce the chromophore, which is then measured spectrophotometrically. Obtaining absorption at two wavelengths permits a differentiation of porphobilinogen from interfering reactants not removed by the resin treatment. This assay is relatively simple, dependable, highly reproducible for increased amounts, and more specific than the qualitative assay.
Quantitation of Serum Urea as Microcapillary Columns of Dixanthylurea
Authors: Searcy R L , Korotzer J L , Douglas G L , Bergquist L M
Published: January 2020

A simple technic is proposed for direct estimation of urea in terms of columns of dixanthylurea precipitated from serum. The procedure is reproducible and yields results comparable to those obtained colorimetrically using normal and uremic sera. An equation has been derived which permits conversion of levels of dixanthylurea columns, in millimeters, to urea nitrogen concentrations. The new method is useful in detecting as well as monitoring cases of uremia.
Comparison of Enzyme Activities of Arterial Samples from Sexually Mature Men and Women
Authors: Kirk John Esben
Published: January 2020

A comparison was made of activities of 25 different enzymes in aortic, pulmonary artery, and coronary artery samples derived from 18- to 54-year-old men and women. The aorta and coronary artery of women were found to contain lower concentrations of 4 TPN-dependent enzymes (glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, isocitric dehydrogenase, and TPN-malic enzyme). Since TPNH is a compound involved in the synthesis of cholesterol and fatty acids, the observed sex difference in arterial TPN-dependent enzyme activities may be associated with the lower susceptibility of premenopausal women to arteriosclerosis.
Studies on the Determination of Bile Pigments
Authors: Stevenson G W , Jacobs S L , Henry R J
Published: January 2020

The absorbance at 450 mµ of serum diluted with acidified ethylene glycol is used as a measure of the serum's total bilirubin content in a single-tube, single-extraction method for rapid determination of free and total bilirubin in 0.1 ml. of serum. With the addition of chloroform, free bilirubin is extracted into the chloroform but conjugated bilirubin remains in the ethylene glycol. Free bilirubin is determined from the absorbance at 450 mµ in the chloroform layer. Conjugated bilirubin is calculated from the difference. Absorbance readings at 520 mµ compensate for the absorbance at 450 mµ, due to hemoglobin in the serum. Comparison with the Malloy-Evelyn procedure showed equivalent levels of total but higher levels of conjugated bilirubin.
A Diagnostic Test for Fructosuria
Authors: Sarma P L
Published: January 2020

As little as 8 µg fructose can be identified by the red or yellow color produced by adding 2 drops of a fructose solution to approximately 0.2 gm. of potassium hydroxide on a spot plate. Glucose interferes with this test only when less than 0.1 mg. of fructose is present in a mixture of more than 0.9 mg. of glucose. This test may be used for a rapid diagnosis of fructosuria if 0.5% or more of fructose is excreted in the urine.
A Comparison of Some Methods of Cholesterol Measurement
Authors: Hawthorne Betty E
Published: January 2020

Five referee sera were analyzed for total cholesterol at several laboratories by up to 10 different methods or modifications. Results by any method varied less within a single laboratory than among laboratories, although the ranges of replicate analyses reported differed considerably. Those methods including procedures for saponification with potassium hydroxide and some isolation of cholesterol from other chromogens by digitonin precipitation or re-extraction into petroleum ether, in general, yielded results somewhat lower than those obtained by methods which did not include these procedures.
A Simplified Technique for Determination of Small Amounts of Calcium as Oxalate
Authors: Van Slyke Donald D , Carson Paul E
Published: January 2020

Procedures for determination of calcium by oxalate precipitation are reviewed, and a method is described in which the calcium oxalate precipitate is both formed and washed in a filter tube with a fritted-glass filter. Washing with saturated calcium oxalate solution is completed in 1-2 min. The washed precipitate is redissolved in perchloric acid solution and the dissolved oxalate is either titrated or determined manometrically by the CO2 evolved from oxidation with ceric sulfate.
Rapid Determination of Plasma Ammonia by an Ion-Exchange Technic
Authors: Forman Donald T
Published: January 2020

A method is described for the colorimetric determination of ammonia in plasma by a batch ion-exchange procedure. The method combines separation of ammonium ion, using a strongly acidic cation-exchange resin, with a sensitive colorimetric procedure which simultaneously elutes and colorimetrically reacts with the ammonium ion to produce a stable color.

Interference by basic amino acids is negligible, and the great sensitivity of the color reaction permits the measurement of ammonia of the order of 0.5 µg./ml. The effects of variations in the experimental conditions are examined, and the results of recovery experiments and other tests of precision and accuracy are reported. In comparison with other methods in current use, this method has distinct advantages in sensitivity, simplicity, and rapidity of determination, provided the conditions and methods of measurement are controlled carefully.
Effect of Toluene and Similar Compounds on the Carbohydrate-Anthrone Reaction
Authors: Devor Arthur W , Baker William L , Devor Kenneth A
Published: January 2020

Toluene interferes with the anthrone reaction for hexoses causing a decrease in the absorption maximum at 625 mµ and producing a second absorption band with a maximum at 475 mµ. Xylene, benzene, and cyclohexene also interfere, whereas cyclohexane, o-chlorobenzene, and benzoic acid do not.
Decolorization on Freezing of Ferricyanide-Cyanide Solution used for Hemoglobin Determinations
Authors: Mickelsen Olaf , Woolard Helen , Ness Arthur T
Published: January 2020

When Drabkin's solution (used for the determination of hemoglobin), which contains K3Fe(CN)6, KCN, and NaHCO3, is frozen, it loses its greenish-yellow color. The solution remains colorless even after thawing. The reaction, for which there is no satisfactory explanation, involves the reduction of the K3Fe(CN)6 to K4Fe(CN)6, with KCN being oxidized to KCNO.
Serum Glycoproteins and Seromucoid in Patients with Myocardial Infarction
Authors: Keyser J W , Stephens B T
Published: January 2020

Seromucoid and serum total glycoproteins were measured in 7 patients with myocardial infarction. In all cases the highest concentrations of these proteins were reached several days after the concentration of glutamic-oxalacetic transaminase had begun to return to normal. In 2 cases paper electrophoretic analysis of the serum proteins was performed. A rise in the concentration of 1- and 2-globulins occurred after infarction, and PAS staining indicated that the rise in total glycoprotein was largely or entirely accounted for by these two fractions. The concentration of serum albumin fell considerably after infarction, reaching a minimum at about 6 days; - and -globulin concentrations appeared to fall slightly. In general, the presence of C-reactive protein corresponded roughly with the period during which the seromucoid concentration was elevated. It is suggested that the elevation of seromucoid and total glycoproteins represents a nonspecific response to the tissue injury.
Bovine Serum Ultrafiltrate as a General Standard in Clinical Chemical Analysis
Authors: Saifer Abraham , Deutscher Claire
Published: January 2020

This survey has shown some facts of considerable interest to the clinical chemist.

First, it is evident that bovine blood serum ultrafiltrate constitutes one of the best general standards so far developed for clinical chemical control analysis. It is a stable product that can be prepared in large lots and kept for relatively long periods of time by storage in a refrigerator. Such a standard will be extremely useful in clinical chemical laboratories in the standardization of their technics and as an aid in the elimination of systematic errors of analysis and in routine laboratory control. On the other hand, the absence of serum proteins and sterols precludes the use of this standard for the analysis of these constituents. The second fact that emerges from this survey is that errors in clinical chemical analysis still occur. The finding that individual results from selected laboratories have been in error, imposes the obligation of periodic control checkups by the chemist charged with the supervision of the laboratory.

Finally, a general standard of this sort permits an exhaustive comparison of different methods for any given constituent without fear of variation from sample to sample.
Serum Globulin Fractions in Chronic Rheumatic Diseases
Authors: Salt Harold B
Published: January 2020

Investigations into the serum protein patterns that occur in chronic rheumatic diseases, formerly made by salt-fractionation methods, are now revised with the aid of the superior technic of microelectrophoretic separation.

Using the microelectrophoretic method, supplemented by a single salt-fractionation procedure, the concentrations of albumin, α1-globulin, α2-globulin, β-globulin and γ-globulin in the sera of 26 patients variously affected by chronic rheumatic diseases were determined.

Normal protein patterns were found in all the 12 sera with normal total globulin content, whereas variously abnormal protein patterns were found in all of the 14 hyperglobulinemic sera.

The hyperglobulinemia of chronic rheumatic diseases was found most frequently to be due to increments in γ-globulin, often accompanied also by increases in α2-globulin. Less frequently, increased amounts of β-globulin were found, and in some cases an elevation of α1-globulin. These abnormalities were all detectable electrophoretically, whereas the method for the salting-out of γ-globulin was unsatisfactory.
Yeast Adenylic Acid as a Substrate for Serum Acid Phosphatase
Authors: Reynolds Orland B , Reynolds Moira Davison , Walker Burnham S
Published: January 2020

Yeast adenylic acid was investigated as a substrate for serum acid phosphatase determination. It was compared as a substrate primarily with β-glycerophosphate and found to be very similar in selectivity and sensitivity. There appears to be no significant advantage in the use of yeast adenylic acid over β-glycerophosphate for this purpose.
Buffer Composition in Paper Electrophoresis
Authors: Laurell C B , Laurell S , Skoog Nancy
Published: January 2020

An apparatus is described for paper electrophoresis according to the moist-chamber principle. A simple method for quantitative evaluation of the different electrophoretic fractions is presented together with the limits for the normal variation of the different serum fractions.

The influence of the composition of the buffer on the separation of the proteins is stressed.

Addition of small amounts of calcium ions results in a separation of the β-fraction into two distinct fractions, β1 and β2Ca. The mobility of β-lipoproteins is decreased in the presence of calcium. The phenomenon was confirmed with the aid of moving-boundary electrophoresis. The refractive contribution of the lipids in the β-lipoproteins in moving-boundary electrophoresis is shown. The mobility of the main β-component containing carbohydrate and of the transferrin is not changed by calciumion.
Urinary Estrogens in Pregnancy
Authors: Anker Rudolph M
Published: January 2020

A new method has been described for the cleavage of the estrogenic steroid conjugates occurring in the urine of pregnant women. It yields higher estrogen values than the methods which have been employed in the past.
Vanadium Concentration of Urine
Authors: Rockhold W T , Talvitie N A
Published: January 2020

A rapid, convenient test for the estimation of small amounts of vanadium in urine is described. The method is based on the catalytic effect of vanadium on the oxidation of N, N-diethyl-p-phenylenediamine by potassium chlorate. Only 1 ml. of urine is required and the test is sensitive to quantities of vanadium as low as 0.01 µg. per ml. of urine. Semiquantitative analyses can be made over a range of 0-1 µg. of vanadium per ml. of urine. The test is designed for application in rapid clinical analyses on small amounts of urine to determine possible vanadium absorption and is suggested for use as a screening test to determine on-the-job exposure of workers to vanadium compounds in excess of the suggested threshold limit value. Data showing the application of the test in several species are given.
New Biuret Reagent for the Determination of Proteins in Cerebrospinal Fluid
Authors: Rosenthal Harold L , Cundiff Helen I
Published: January 2020

A new biuret reagent is described which contains disodium ethylen diamine tetraacetate as the copper stabilizing agent. The reagent effectively prevents the formation of cloudiness in determinations of cerebrospinal fluid due, in part, to the precipitation of calcium in alkaline solution. Results obtained with the new reagent compare favorably with those obtained by Kjeldahls analysis.
Quantitative Cephalin-Cholesterol Flocculation Test for Liver Function
Authors: Kibrick Andre C
Published: January 2020

The quantitative cephalin-cholesterol flocculation test of the author has been modified to give values in percentage of the absorption of the control tube with saline. This simple test which involves only a measurement of absorption in the centrifuged supernatant fluid may be used with any photoelectric colorimeter. Data are presented to show that in 29 of 35 serums giving values above 40 per cent the patients have other evidence of liver disease, while in only 5 out of 45 serums giving values below 40 per cent, the patients have possible liver damage. The same consistency in the results on 296 other patients is reported.
Affinity Characteristics of Amylase-Binding Substance(s) Prepared from Macroamylase Complexes
Authors: Fridhandler L , Berk J Edward , Wong Deborah
Published: January 2020

Partially purified macroamylase complexes, subjected to chromatography at pH 3.4, were partly or completely dissociated in each of the 30 sera so studied. The protein fractions contained variable quantities of residual undissociated macroamylase. They also contained binding substance(s), as evidenced by ability to bind added amylase. Pancreatic and salivary amylase were separately mixed with each preparation of binding substance(s) and chromatographed. Binding affinity, measured by the activity of newly formed macroamylase, varied considerably. Most of the binding substances bound considerably more salivary than pancreatic amylase; none showed markedly greater affinity toward pancreatic than toward salivary amylase. By and large, there appeared to be an association between the isoamylase pattern of the amylase released from the macroamylase complexes at pH 3.4 and the relative binding affinities of the binding substances toward pancreatic and salivary amylases.
Nature of Isoamylases Released, by Acidification, from Macroamylase Complexes
Authors: Fridhandler L , Berk J Edward , Montgomery K
Published: January 2020

We describe observations of the isoamylase nature of the amylase released by acid from partially purified macroamylase complexes that are dissociable under acid conditions. The released isoamylases displayed the chromatographic characteristics previously found in the pancreatic type (P-type) and salivary type (S-type) of amylases in human serum and urine. The proportions of S- and P-types released from 30 macroamylase complexes varied over a much wider range than those proportions found in 27 normal sera. Of particular note was the relatively large number of cases in which there was a marked preponderance of S-type in the released amylase. These data testify further to the varied nature of cases of macroamylasemia, and contribute additionally to their systematic classification.
Rapid Two-Dimensional Immunoelectrophoresis of Human Serum Proteins
Authors: Wright G L , Pollack Louis , Roberts D B
Published: January 2020

We describe two versions of a two-dimensional immunoelectrophoretic system and illustrate their use for separating and estimating human serum proteins. Each is sensitive, rapid, and simple to perform, and requires no special apparatus and only 0.1-0.6 ml of antiserum. Both procedures appear to be potentially useful in the clinical laboratory. Time required to obtain a stained pattern varies from 4.5 to 7 h, depending on the intended purpose and sensitivity (number of possible precipitin peaks) desired. With the faster method ("rapid screening") 25 to 35 precipitin peaks are detected. With the slower but more sensitive method 40 to > 50 peaks are detected. The sensitivity of either version is a function of the titer of the polyvalent antiserum to whole human serum. Of the precipitin peaks thus far detected, 35 have been identified.
Direct Determination of Total Serum Phospholipid by X-Ray Fluorescence
Authors: Leyden Donald E , Carr Peter W , Nonidez William K
Published: January 2020

An x-ray fluorescence method for measurement of total serum phospholipid is described. A Folch extract of 1 ml of serum is evaporated and deposited on a paper disc by washing with chloroform. A coefficient of variation of 4% was obtained for samples containing at least 1 micromole of lipid, as phosphorus. The major advantage of the method is its speed (5 min/sample) in comparison to the phosphomolybdenum blue procedure. The method is free of interference from other lipid constituents and phosphorous content can be standardized by comparison with very stable inorganic phosphates.
Systematic Bias between Blood-pH Instruments
Authors: Ladenson Jack H , Smith Carl H , Dietzler David N , Davis J E
Published: January 2020

Measurement of tris(hydroxymethyl)aminomethane buffers and blood samples was used to compare the following commercial pH instruments: Corning Models 160 and 165, Instrumentation Laboratory, Inc. Model 313, and Radiometer Models E5021 and BMS 3MK2. These comparisons uncovered a systematic bias of 0.02 pH units in Instrumentation Laboratory, Inc. electrodes manufactured before April 1973. Other factors found to affect analytical results were the temperature of the saturated KCl salt bridge and reference electrode, the design of the temperature-control system, and the buffer used to standardize the instruments.
Re-evaluation of EDTA-Chelated Biuret Reagent
Authors: Chromý V , Fischer J , Kulhánek V
Published: January 2020

We studied the optimal composition of EDTA-chelated biuret reagent for the determination of protein in serum. A reagent containing 18 mmol of EDTA, 15 mmol of Cu2+, and 1 mol of NaOH per liter exhibits a very low blank but about the same sensitivity as tartrate-chelated reagents. Maximum color intensity is attained within 25 min at room temperature, and adheres to Beer's law up to 120 g of protein per liter.
Formaldehyde Interference with the o-Toluidine Procedure for Glucose
Authors: Bond Lawrence W , Savaria Anita M , McComb Robert B
Published: January 2020

Formaldehyde, in the quantities normally used to preserve uric acid—gluose reference quality-control solutions, interferes with glucose analysis of these solutions by the o-toluidine procedure. This effect is enhanced by the uric acid present and is observed with other aldehydes.
Application of a Vidicon Spectrometer for Simultaneous Flame-Emission Analysis for Sodium and Potassium in Serum
Authors: Cook Thomas E , Milano Michael J , Pardue Harry L
Published: January 2020

We describe a unique new approach to analytical spectroscopy, which makes use of a silicon-target vidicon tube to rapidly and repetitively scan ultraviolet and visible spectra. We discuss the concept and characteristics of the vidicon spectrometer and illustrate its application to simultaneous determination of sodium and potassium in serum by flame photometry. Average values of coefficients of variation for sodium and potassium are 1.1% and 1.7%, respectively. Recoveries of sodium and potassium added to sera were 99.5% and 99.8%, respectively. When the same burner and flame conditions were used with the vidicon spectrometer and a conventional flame photometer, deviations among results were well within ±3 mmol/liter for sodium and 0.2 mmol/liter for potassium. A bias is observed for both elements when results obtained with an air-hydrogen flame are compared with results obtained with an air-propane flame. Our data illustrate that the vidicon spectrometer is a viable tool for both routine applications and basic studies of effects of flame conditions on two or more elements simultaneously.
Feasibility of Recording Clot Lysis with the Thermometric Clot Detector
Authors: Bostick William D , Carr Peter W
Published: January 2020

We investigated the possibility of continuously recording the process of clot lysis with a thermometric clot detector. Experiments in which fibrinolytic activators and inhibitors were used demonstrate that the detection system, without any mechanical modifications, is suitable for monitoring the complete coagulation process from clot formation to the ultimate lysis of the clot itself.
Some Marker Dyes for Locating Steroids Eluted from Sephadex LH-20 Columns
Authors: Drewes Patricia A , Kowalski Adalbert J
Published: January 2020

As a routine internal calibration system, the use of marker dyes is easier, faster, and more reliable for precisely locating steroids separated by column chromatography on Sephadex LH-20 than is the customary method, pre-calibration by radioactivity. Certain azobenzene and azotoluene dyes are suitable for signaling the effluent positions of various steroids of clinical interest. The elution behavior of this group of dyes is described for two nonpolar solvent systems commonly used in steroid chromatography; however, the technique is generally applicable and this group of dyes may be generally useful as visual markers.
Calculations and Correction Factors Used in Determination of Blood pH and Blood Gases
Authors: Burnett Robert W , Noonan Daniel C
Published: January 2020

Measurement of blood pH, po2 and pco2 also involves calculation of two or more derived quantities and correction of the measured values in cases where the body temperature of the patient differs from the temperature of measurement. References to the pertinent calculations and the temperature corrections are scattered through the literature of several medical specialties, and much new information has been gathered in recent years that directly affects these calculations. This review explains each of the derived quantities and correction factors most used in this field and also provides the best available data for the calculations, in a form that can readily be adapted to electronic data processing.
Factors Contributing to Intra-Individual Variation of Serum Constituents: 3. Use of Randomized Duplicate Serum Specimens to Evaluate Sources of Analytical Error
Authors: Bokelund Henning , Winkel Per , Statland Bernard E
Published: January 2020

In study of intra-individual variation of serum constituents, we used analysis of variance to separate biological from analytical variation, the latter being estimated from results for duplicate specimens. However, the replication error term in such a model may grossly overestimate instrumental variability, especially when a significant pre-instrumental error component is present. To separate pre-instrumental and instrumental error, we used the following experimental design: Duplicate serum specimens were obtained from 88 healthy men, the blood being collected at one venipuncture and immediately divided into two portions. The duplicates were randomized and analyzed on one occasion with the "AutoChemist Multi-Channel Analyzer," and pre-instrumental variation was estimated from the results. Instrumental variation was estimated from results for three independent populations with widely different mean analyte concentrations; these samples were analyzed at the same time as the samples just mentioned. Of the 20 serum constituents assayed, sodium, potassium, iron, total lipids, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and total bilirubin showed significant pre-instrumental error components, as evidenced from significant χ2-tests comparing analytical and "duplicate sample" variation. For total serum protein, albumin, total lipids, cholesterol, and alkaline phosphatase, we found a significant difference (by paired t-test) between values for the first and second specimen.
Trace-Element Analysis in Hair: An Evaluation
Authors: Hilderbrand David C , White Dari H
Published: January 2020

The use of hair as an index to the concentration of certain elements in tissues has been evaluated with regard to the effect of prior cosmetic and sample-washing treatments on the results. Untreated rat-hair samples were subjected to selected grooming or cosmetic products and then washed by various commonly cited sample-preparation procedures. The hair samples were then analyzed for Ca, Mg, Cu, and Zn, and the concentrations found were compared to those in untreated samples. The results indicate that the values observed can be greatly altered by typical treatments given to human hair, and that such changes are not corrected by the commonly used sample-wash procedures. Thus, obtainable samples of human hair, including pubic hair, cannot be expected to indicate accurately the concentration of these metals that would otherwise be present. Other elements should be similarly studied before confidence can be placed in the validity of data for them.
Furosemide Concentrations in Serum and Urine, and Its Binding by Serum Proteins as Measured Fluorometrically
Authors: Forrey A W , Kimpel B , Blair A D , Cutler R E
Published: January 2020

We describe a modification of the fluorometric method of Häussler and Hajdú [Arzneim. Forsch. 14, 704 and 709 (1964)] for assay of furosemide in either serum or urine. A 1-ml sample, acidified to pH 2, is extracted with 5 ml of diethyl ether; 4 ml of the ether is back-extracted into 1 ml of phosphate buffer (pH 7.0, 0.1 mol/liter), and finally acidified with 1 ml of dilute HCl (0.6 mol/liter). A procedure for estimating blanks in urine was derived to correct for dilution caused by diuresis. Internal standards are used, and the "effective" extraction ratio is used to correct for the effects of quenching and extraction differences. In equilibrium, 93% of the drug is bound to serum proteins; 65% is tightly bound. Erythrocytes contain less than 5% of the drug. Quantum yield of fluorescence at pH 1 is 0.0496 for furosemide and is 0.0163 for 4-chloro-5-sulfamoylanthranilic acid. Furosemide fluorescence diminishes with increasing pH, while that of 4-chloro-5-sulfamoylanthranilic acid (a degradation product) increases.