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Biomedical subjects

T M Williams

Publications and source records attributed to T M Williams.

144 records · Page 8Linked to original sources
PubMed1983

Locomotion in the North American mink, a semi-aquatic mammal. II. The effect of an elongate body on running energetics and gait patterns.

Oxygen consumption (VO2) of minks increased non-linearly with running speed over the range of 0.70-6.40 km h-1. A break in the VO2 vs speed relationship occurred at approximately 3.94 km h-1 and corresponded to the transition from a walking to a half-bounding gait pattern. Incremental transport costs associated with bounding were 36% lower than for walking at similar speeds. The lower energetic cost of bounding was attributed in part to low stride frequencies and in part to spinal flexion. The latter was particularly important in circumventing stride length restrictions associated with the short limbs of these animals. As a result, stride frequency and stride length of these elongate mustelids at the gait transition speed were similar to values predicted for conventionally-shaped mammals.

Animals↗
PubMed1983

Immunopathology of murine experimental allergic orchitis.

Experimental allergic orchitis (EAO) was induced consistently in BALB/c mice by immunization with homologous testicular tissue homogenate emulsified in complete Freund's adjuvant (CFA) providing that the animals had received simultaneously at least 1 microgram of an extract of Bordetella pertussis rich in pertussigen. All animals thus treated developed orchitis and serum antibody to testicular antigens within 20 days after immunization. The lesions were located in testis (100%), rete testis (37%), cauda epididymis (21%), and vas deferens (37%). Ductus efferentes and caput epididymis were only rarely affected. Early lesions in the seminiferous tubules were characterized by peritubular and/or intratubular accumulation of eosinophils, neutrophils, lymphocytes, and macrophages. This was followed by aspermatogenesis. Late lesions included massive necrosis and extensive fibrosis of the seminiferous tubules. Disruption of blood-testis barrier on day 20 was evidenced by the detection of 1) perfused lanthanum deposits between Sertoli cells and surrounding inflammatory cells inside the seminiferous tubules, 2) deposits of endogenous mouse IgG in germinal epithelium, and 3) probable immune complexes (granular C3) surrounding seminiferous tubules. Murine EAO differed from that of the guinea pig in the lack of involvement of the ductus efferentes, the extensive necrosis, the abundant polymorphonuclear eosinophils in the lesion, and the exquisite requirement of concomitant injection of B. pertussis extract.

Animals↗
PubMed1982

A hematology survey of workers at a styrene-butadiene synthetic rubber manufacturing plant.

A previous epidemiologic study of the U.S. rubber industry indicated that there has been an excess of leukemia and lymphoma mortality among hourly workers at one styrene-butadiene rubber manufacturing plant. This investigation was a combined industrial hygiene and hematology cross-sectional survey at the same plant. The objectives of the survey were to quantify exposure levels for styrene, butadiene, benzene and toluene, and to relate these levels to hematologic variation. Personal air samples and blood specimens were obtained from 157 production workers. All exposure levels for the four chemicals assayed were well below recommended standards. The higher mean styrene (13.67 ppm) and butadiene (20.03 ppm) concentrations were found in the Tank Farm area; in all other departments the mean levels for the four chemicals were less than 2 ppm. The Tank Farm workers had slightly lower levels of circulating erythrocytes, hemoglobin, platelets and neutrophils, and slightly higher mean corpuscular red cell volumes and neutrophil band counts than the other workers. Overall, in this population there was no pronounced evidence of hematologic abnormality, as determined from examination of peripheral blood.

Adult↗
PubMed1982

Compartment syndrome after anti-shock trouser use without lower-extremity trauma.

The use of anti-shock trousers is widely advocated for the treatment of hypovolemic shock. Despite its frequent use, few complications have been reported in the medical literature. Although speculation exists that anti-shock trouser application may result in ischemic injury to the lower extremities, this complication has only recently been reported. Our report describes a patient with no lower extremity trauma who developed bilateral anterior and lateral compartment syndromes after the application of anti-shock trousers.

Adolescent↗
PubMed1980

Worker exposure to chemical agents in the manufacture of rubber tires and tubes: particulates.

The Occupational Health Studies Group industrial hygiene studies at a group of 14 tire and tube manufacturing plants chosen to represent a cross-section of the industry include numerous evaluations of potential exposure to airborne particulate matter. Results of these environmental particulate sampling studies are reported by plant and by occupational groups within plants. High volume, open face and cyclone samplers were employed to evaluate both personnel and area particulate concentrations. The concentrations of particulates yielded by high volume and open face total particulate samplers are compared with those of comparison samples of respirable material. Personnel samples of particulates are compared with general air samples taken in the same work areas. An overall review and comparison is given of particulate exposures to workers in various occupational title groups where particulate materials are released to the air from processes or operations.

Air↗
PubMed1980

Worker exposures to chemical agents in the manufacture of rubber tires: solvent vapor studies.

Environmental sampling surveys have been conducted in ten large tire manufacturing plants across the U.S. to characterize the nature and intensity of current exposure to solvent vapors. These plants were chosen to represent a cross-section of the industry and include both old and new plants, plants of four different companies and plants with wide geographic distributions. A variety of organic solvents is used in the manufacture of tires and tubes; accordingly solvent vapors comprise one category of exposure for workers in specific Occupational Title Groups (OTGs). Approximately 1000 determinations of various solvent vapor components in air samples have been made with special emphasis on pentane, hexane, heptane, benzene and toluene vapor levels. Exposures stem from the widespread use of bulk materials including petroleum naphthas, gasoline and aliphatic and rubber solvents in various tire manufacturing operations.

Air↗
PubMed1976

Studies in the design of x-ray contrast agents. Synthesis, hydrophobicity, and solubility of some iodoresorcyl bis(beta-glucosides).

Two diiodo- and two triiodoresorcyl bis(beta-glucosides) were prepared and their hydrophobicity (log P octano) and water solubility were compared to a triiodophenyl beta-glucoside and several experimental nonionic, water-soluble, x-ray contrast agents. The data indicate steric overlap of the halogen substituents by the bulky hydrophilic O-beta-glucosyl substituents; high water solubility is attained only at observed log P octanol approximately 1.5 or lower. Of the new compounds, only 2,4,-6-triiodo-5-N-methylcarboxamidorescorcy bis(beta-glucoside) (6) was highly water soluble. At the physiological pHin dog's plasmia in vitro, compound 6 rapidly hydrolyzed. Poorly water-soluble but more stable compounds of this series were not appreciably absorbed from dog's duodenum.

Animals↗
PubMed1975

Mitochondrial protein synthesis in a mammalian cell-line with a temperature-sensitive leucyl-tRNA synthetase.

The temperature-sensitive Chinese hamster ovary cell mutant tsH1, has been shown previously to contain a temperature-sensitive leucyl-tRNA synthetase. At the non-permissive temperature of 40 degrees C cytosolic protein synthesis is rapidly inhibited. The protein synthesis which continues at 40 degrees C appears to be mitochondrial, since: (a) whole-cell protein synthesis at the permissive temperature of 34 degrees C is not inhibied by tevenel, the sulfamoyl analogue of chloramphenicol and a specific inhibitor of mitochondrial protein synthesis; however, whole-cell protein synthesis at 40 degrees C is inhibited by tevenel, (b) Protein synthesis by isolated mitochondria from tsH1 cells is not significantly inhibited at 40 degrees C. (c) At 40 degrees C [14C]leucine is incorporated predominantly into the mitochondrial fraction of tsH1 cells. (d) The incorporation of [14C]leucine at 40 degrees C into mitochondrial proteins of tsH1 cells is inh-bited by tevenel but not by cycloheximide. These results suggest that the mitochondria of tsH1 cells contain a leucyl-tRNA synthetase which is different from the cytosolic enzyme. The inhibition of cytosolic, but not of mitochondrial protein synthesis in tsH1 cells at 40 degrees C allows the selective labelling of mitochondrial translation products in the absence of inhibitors. The mitochondrial translation products labelled in tsH1 cells at 40 degrees C and at 34 degrees C in the presence of cycloheximide have been compared by sodium dodecylsulphate-polyacrylamide gel electrophoresis. Both conditions of labelling give similar profiles. The mitochondrial translation products are resolved into two components, one with an apparent molecular weight range from 40,000 to 20,000 and a second with an apparent molecular weight range from 20,000 to 10,000.

Amino Acyl-tRNA Synthetases↗
PubMed1975

Development of multiple dimension use in form classification.

The use of multiple form dimensions in pattern classification was studied with adults and children in grades 2 and 5. Each subject sorted 30 8-sided random polygons first into 2, then into 3, and finally into 4 groups and repeated the procedure 1 week later. A series of discriminant analyses, using 9 physical form characteristics as predictors, was used to answer several developmental questions. Reliability of classification, number and saliency of features selected, and accuracy with which they were used all implied continuous development of perceptual skills. Multiple feature use in classification was evidenced at all age levels.

Achievement↗
PubMedDate not supplied

Method for reducing the rate of light emission from chemiluminescent and bioluminescent reactions using frozen reagents.

Frozen assay reagents have been used to reduce the rate of light emission from the rapid chemiluminescent acridinium ester and the bioluminescent firefly luciferase reactions. Melting of the assay reagent delays the initiation of the light emission, thus eliminating the need to initiate these rapid reactions by injection of the assay reagents in front of the photodetector.

Acridines↗