Search PubMed⌕ Search

Biomedical subjects

D B Thomas

Publications and source records attributed to D B Thomas.

306 records · Page 17Linked to original sources
PubMed1968

The presence of glycopeptide material in cultured mouse mast-cell tumours.

1. Mouse mast-cell tumours P815 Y and HC were shown to contain glycoprotein material composed of glucosamine, galactosamine, sialic acid, galactose and mannose. 2. The major amino acids released after acid hydrolysis of Pronase-treated digests of the glycoprotein are aspartic acid, glutamic acid, serine, threonine, proline, glycine and alanine. The Pronase-digested material is not degraded in alkaline solution. 3. On incubation of mast cells with [(35)S]sulphate, heparin is the major radioactive product. However, [1-(14)C]glucosamine and d-[(14)C]glucose are incorporated largely into the glycoprotein. 4. The fate of [(35)S]sulphate-labelled and [1-(14)C]glucosamine-labelled material was studied. In each case high-molecular-weight radioactive material is released from the cells into the culture medium. The t((1/2)) of [(35)S]sulphate-labelled material in cells is 70hr. and that of [1-(14)C]-glucosamine-labelled material in cells is 40hr. 5. About 60% of the [(35)S]sulphate-labelled material is present in the mitochondrial and granular fraction. [1-(14)C]-Glucosamine-labelled material is present in both microsomal and mitochondrial and granular fractions, [(14)C]sialic acid being concentrated in the microsomal fraction.

Amino Acids↗
PubMedDate not supplied

Echo correlation analysis and the acoustic evidence in the Kennedy assassination revisited.

A Dallas Police Department recording contemporaneous with the Kennedy assassination contains five impulsive sounds that have the acoustic waveform of Dealey Plaza gunfire. One of the sounds matches the echo pattern of a test shot fired from the Grassy Knoll. The shock wave precedence associated with this pattern is consistent with the muzzle velocity of a .30 calibre rifle. Criticism of the acoustic identifications on statistical grounds is based on erroneous assumptions concerning the assignment of values to the parameters that determine the probability that random noises could resemble gunshot patterns. A conservative estimate of the true value of the probability that the putative Grassy Knoll shot is attributable to random radio noise is no greater than 0.037. Alleged asynchroneity of the sounds with the time of the assassination stemmed from several incorrect assumptions. Whatever their origin, the gunshot-like sounds occur exactly synchronous with the time of the shooting.

Journal Article↗
PubMedDate not supplied

Restricted expression of LW antigen on subsets of human B and T lymphocytes.

NIM-M8 is a monoclonal IgM antibody, specific for the LWab antigen as shown by its reaction with red cells of all donors except those lacking LWa, LWb and LWab. Indirect immunofluorescent staining and cell sorter analyses have shown that LWab is present on a subpopulation of human lymphocytes. Cell fractionation studies indicate that subsets of both B and T cells express LWab and it may, therefore, provide a further marker for heterogeneity in these lymphocyte populations.

Antibodies, Monoclonal↗
PubMedDate not supplied

Thyroid hormones and duration of ovulatory activity in the etiology of breast cancer.

We conducted the present study with the hypothesis that conflicting reports on the association between mild hypothyroidism and breast cancer may be due to failure to consider the potential interaction between thyroid and ovarian hormones. Seventy-three cases of breast cancer and 75 hospital controls were studied. The overall matched multivariate odds ratio of breast cancer for the lowest tertile of free T4 (< or = 1.10 ng/dl) versus the two other tertiles was 1.7 (95% confidence limits, 0.6-5.0). However, there was a statistically significant linear trend (P = 0.04) in the odds ratios for breast cancer related to subnormal free T4 levels across tertiles of duration of ovulatory activity. These results suggest that women combining low levels of circulating free T4 with long duration of ovulatory activity may be at increased risk for this disease.

Adult↗
PubMedDate not supplied

Consumption of nitrate, nitrite, and nitrosodimethylamine and the risk of upper aerodigestive tract cancer.

Evidence from animal studies indicates that various N-nitroso compounds are carcinogenic. We investigated whether consumption of foods and beverages containing nitrosodimethylamine, nitrites, and nitrates affected the risk of laryngeal, esophageal, and oral cancer. In a population-based case-control study in western Washington state, dietary consumption of these substances was measured in 645 cases (169 laryngeal, 125 esophageal, and 351 oral) and 458 controls. After adjustment for tobacco, alcohol, and other known risk factors, there was a 52% reduction in the risk of upper aerodigestive tract cancer for individuals who consumed higher amounts of nitrate (upper tertile) compared with the lowest tertile (P < 0.001 for trend). Nitrate intake was associated with a reduction in cancer risk at all three sites. The reduction in the risk of esophageal cancer with increasing nitrate consumption was more evident in frequent tea drinkers than in other subjects. There was no significant association between nitrite consumption and the risk of laryngeal or oral cancer. However, for individuals with a history of canker sores (an indicator of possible endogenous nitrosation), the risk of esophageal cancer was seven times greater in those with high versus low nitrite intake. Consumption of foods high in nitrosodimethylamine was associated with a 79% increased risk of upper aerodigestive tract cancer (P = 0.037 for trend). Cases consumed smoked fish more frequently than did controls [odds ratio (OR) = 3.03]. Daily intake of beer and of nitrite-containing meats were associated with an increased esophageal cancer risk (OR = 2.48 and 1.82, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Drinking↗
PubMedDate not supplied

A case-control study of element levels and cancer of the upper aerodigestive tract.

A population-based case-control study was conducted in western Washington state to investigate possible dietary risk factors for laryngeal, esophageal, and oral cancers. Using results from a food frequency questionnaire, past dietary intakes of iron, zinc, and calcium were estimated for 661 cases and 466 controls. Clippings were also taken from the nails of both halluces to determine concentrations of iron, zinc, calcium, chromium, and cobalt in 507 of the cases and 434 of the controls. After adjustment for smoking, alcohol, and dietary beta-carotene and vitamin C intake, individuals who reported dietary intakes of iron and zinc in the upper quartile were less likely to develop cancers of the larynx and esophagus than were individuals with intakes in the lowest quartile [odds ratios (OR), 0.5 for iron and 0.1 for zinc]. However, there were no significant differences in zinc concentrations in nail tissue between subjects with these types of cancer and controls. Esophageal cancer cases had higher nail concentrations of iron and calcium than did controls (OR, 2.9 for high versus low quartiles of iron; OR, 2.6 for high versus low quartiles of calcium). Individuals who developed esophageal or oral cancer were more likely to have elevated cobalt concentrations in their nail tissue than were individuals without cancer (OR, 9.0 and 1.9 respectively, for high versus low quartiles). The results of this study suggest that there may be differences in mineral intake or metabolism between individuals who develop some carcinomas of the upper aerodigestive tract and those who do not.

Adult↗