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Biomedical subjects

T R Williams

Publications and source records attributed to T R Williams.

At least 37 records · Page 2Linked to original sources
PubMed1992

A profile of tobacco use among teenage dependents.

This study profiles tobacco use by 2,241 dependent teenagers in grades 6-12 at two Army posts. Data were collected in February 1989 by self-administered questionnaires. Results show 40.9% of dependent teenagers have tried smoking and 16.4% have tried smokeless tobacco. Most youths who tried tobacco did so experimentally. Current use is 10.4% smoking and 2.8% smokeless tobacco. While there is little difference in the proportion of boys and girls who have tried or currently smoke, trial and current use of smokeless tobacco is almost exclusively by males. Whites are more likely to ever use tobacco than other ethnic groups.

Adolescent↗
PubMed1992

Reaction of Army families with grade school children to the Active Duty Dependents Dental Insurance Plan.

In March-May 1988, we collected data on enrollment of 1,445 Army families with grade school children in the Active Duty Dependents Dental Insurance Plan at two Army posts. We also surveyed their reactions to the plan. Results show that, although nearly two-thirds of families are enrolled in the plan, most consider the plan a loss of benefits and coverage inadequate. Queues and limited services at military clinics are primary reasons for joining; poor coverage of the dental insurance plan is the main reason for not. A majority of families are willing to pay more for expanded coverage.

Adolescent↗
PubMed1991

Freshwater crabs and Simulium neavei in east Africa. III. Morphological variation in Potamonautes loveni (Decapoda: Potamidae).

Potamonautes loveni (Colosi) is the valid name for the species also described as P. granviki, P. harvardi and P. loveni longimerus, and incorrectly identified as P. berardi berardi. Potamonautes jeanelli and P. idjwiensis may be allied to P. loveni, but are geographically separated and show sufficient morphological distinction not to be considered conspecific. Potamonautes loveni occurs in the upper reaches of rivers on the highlands of western Kenya and eastern Uganda. Its replacement by other species, principally P. niloticus, at lower altitudes is probably determined by the temperature range of the water. Potamonautes loveni has been observed to coexist with P. niloticus within the range of altitude 1280-1950 m. Distinct forms of P. loveni, differing in colour, size and the expression of the post-frontal crest, occur on the western side of Mt. Elgon and in the former ochocerciasis foci of Kenya. Hybridization is evident in populations from between these areas. Morphological divergence within P. loveni may be the result of past climatic change. Periods of generally lower temperature have been accompanied by increased aridity and reduction of forest cover. It is suggested that these conditions are such as to promote a disjunct distribution of P. loveni, and in particular the isolation of the Mt. Elgon population.

Animals↗
PubMed1991

Single-lung transplantation for pulmonary vascular disease.

Six patients with end-stage pulmonary vascular disease received right SLTs. Though patients generally had difficult early postoperative courses, four of the six have survived from 3 to 23 months and have achieved good recovery of right ventricular function and good functional results. SLT is a viable option in selected patients with severe pulmonary hypertension even when right ventricular function is severely impaired.

Female↗
PubMed1990

Sequence analysis of bovine lens aldose reductase.

The covalent structure of bovine lens aldose reductase (alditol-NADP+ oxidoreductase, EC 1.1.1.21) was determined by sequence analysis of peptides generated by specific and chemical cleavage of the homogeneous apoenzyme. Peptides, purified by reverse-phase high performance liquid chromatography were subjected to compositional analysis and sequencing by gas-phase automated Edman degradation. Aldose reductase was found to contain 315 amino acid residues. The enzyme is blocked at the amino terminus, and mass spectrometry was employed to identify the blocking acetyl group and to sequence the amino-terminal tryptic peptide. The aldose reductase was shown to contain no carbohydrate despite the fact that the enzyme contains the consensus sequence -Asn-Lys-Thr- for N-linked glycosylation. Comparative sequence analysis and application of algorithms for prediction of secondary structure and nucleotide binding domains are consistent with the view that aldose reductase is a double-domain protein with a beta-alpha-beta secondary structural organization. The NADPH binding site appears to be associated with the amino-terminal half of the enzyme. Modeling studies based on the tertiary structures of dihydrofolate and glutathione reductases indicate that the NADPH binding site begins at Lys-11 and continues with a beta-alpha-beta fold characteristic of nucleotide binding proteins.

Aldehyde Reductase↗
PubMed1990

Hyperthermic isolated perfusion with melphalan in the treatment of advanced malignant melanoma of the lower limb.

A retrospective study of 91 patients with malignant melanoma treated by lower limb isolated hyperthermic regional perfusion was performed. Objective response in patients with evaluable disease was 78 per cent. The role of perfusion as primary treatment of large melanomas of the foot is confirmed and recommended. Control of locoregional disease and limb salvage remains a valuable and attainable therapeutic goal using this technique.

Chemotherapy, Cancer, Regional Perfusion↗
PubMed1990

1H magnetic resonance imaging study of bovine ocular tissue.

The present study used magnetic resonance imaging (MRI) to study bovine eyes using proton magnetic resonance at a 7-tesla field. The MRI images provide detailed structural information on various sections of the ocular tissues. Detailed images of the lens show several well-defined areas of water content. Relative rankings of various structures of the eye are obtained based on T1, T2 and spin density.

Animals↗
PubMed1989

Changes in taurine in aging fruit flies and mice.

The whole-body concentration of the amino acid taurine was found to be more than 1000% higher during the adult stage of Drosophila melanogaster than during the larval stage. Drosophila larvae were killed by adding taurine (0.01 to 0.10 M) to their food medium. Adult Drosophila failed to produce progeny when fed 0.2 M taurine for one week. Lifetime feeding of taurine (0.05 to 0.20 M) produced no change in life span. Feeding the taurine precursor, hypotaurine, and the taurine mobilizing agent, beta-alanine, to Drosophila did not change life span at low concentrations but both decreased life span at higher concentrations. Taurine concentration in male C57BL/6J mice increased with aging in the heart, decreased in leg muscle and remained unchanged in brain, liver, kidney, and blood. We suggest that an as yet undefined developmental process is altered in Drosophila by taurine and that this process may be unique to insects.

Aging↗
PubMed1988

Squamous cell carcinoma of the head and neck treated with radiation therapy: the impact of neck stage on local control.

There have been several recent reports in the literature to indicate that the risk of failure at the primary site following radiation therapy is greater in patients with a clinically positive neck as opposed to those with a clinically negative neck at diagnosis. This is an analysis of 526 patients with squamous cell carcinoma of the head and neck who were treated with irradiation alone to the primary lesion with curative intent. All patients had follow-up for at least 2 years and were evaluable for analysis of local control. For each site and T stage, no evidence was found to indicate that the primary lesions were controlled less often in patients whose necks were clinically positive than in those whose necks were clinically negative.

Carcinoma, Squamous Cell↗
PubMed1987

Mitochondrial DNA and life span changes in normal and dewinged Drosophila at different temperatures.

At 11 and 30 degrees C there was no change in the amount or in the buoyant density of nuclear DNA of male Oregon R Drosophila melanogaster with aging. When normal flies were maintained at 11 degrees C (at which temperature they do not fly), mitochondrial DNA content declined gradually with aging and 39.4% of the original mitochondrial DNA was lost at the median survival time of 152 days of age. For normal flies maintained at 30 degrees C, 86.5% of the mitochondrial DNA was lost during aging at the median survival time of 25 days. In contrast only a 39.2% decrease in the mitochondrial DNA occurred in dewinged flies maintained at 30 degrees C. A slow phase of mitochondrial DNA loss appears to be related to aging and a fast phase to flight activity. Removing the wings of flies eliminates the fast phase of DNA loss but only slightly improves life span (by less than 10%). Lowering the environmental temperatures to 11 degrees C also eliminates fast phase DNA loss and decreases the rate of the slow phase DNA loss. We conclude that mitochondrial DNA loss is related to both physical activity and to the aging process itself.

Aging↗
PubMed1986

Determination of the state and content of water in normal avian, fish, porcine, bovine, and human lenses as studied by differential scanning calorimetry.

Differential scanning calorimetry was used to measure the relative amounts of 'bulk' and 'bound' water in normal avian, bovine, fish, human, and porcine lenses. The amounts of bound water (mg bound water/mg lens dry weight) found in avian and porcine lenses were statistically different from each other in addition to being statistically different from fish, human, and bovine lenses. There were no significant differences in the mean values between human, fish, and bovine lenses. Avian lenses had the highest amount of bound water, while fish lenses had the lowest bound water content. Significant differences in total water content (mg total water/mg lens dry weight) were observed between all of the lenses, with the exception of bovine and human lenses which were not statistically different. Fish lenses had the lowest amount of total water, and avian lenses had the highest total water content. There were significant differences in bulk water content (mg bulk water/mg lens dry weight) between all of the lenses. Avian lenses had the highest bulk water content, and fish lenses had the lowest bulk water content.

Adult↗