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Biomedical subjects

M C Thomas

Publications and source records attributed to M C Thomas.

At least 109 records · Page 6Linked to original sources
PubMed1991

Carcinogenic ranking of aromatic amines and nitro compounds.

A scheme is proposed for ranking the carcinogenicity of aromatic amines and nitro compounds based on both qualitative (weight of evidence) and quantitative (carcinogenic potency, i.e. the TD50 value) factors. The scheme has been drawn up specifically with a view to linking with workplace hygiene controls. Other essential features are that a reliable database exists for the TD50 values for many compounds and that the scheme is capable of usage by non-toxicologists. Validation of the scheme using 38 aromatic amines or nitro compounds indicates that the main objectives have been met. Extension to different chemical classes should be possible but has not been attempted in this work. An example of a potential hygiene control scheme for use alongside the carcinogenicity ranking is described.

Amines↗
PubMed1991

Alpha 1 antitrypsin phenotypes and alcoholic pancreatitis.

Altered frequencies of alpha 1 antitrypsin phenotypes have been reported in patients with chronic pancreatitis, suggesting a possible genetic basis for individual susceptibility to this disease. Alpha 1 antitrypsin phenotypes, with particular regard to alcoholic pancreatitis, were studied. Patients with alcoholic pancreatitis were compared with alcoholic control subjects with no history of pancreatic disease. Serum alpha 1 antitrypsin concentrations were raised in pancreatitis patients sampled within one month of an acute attack of pancreatitis, but otherwise values were similar to those of control subjects. There were no significant differences in alpha 1 antitrypsin phenotypes between alcoholics with pancreatitis and alcoholic control subjects. This study of alpha 1 antitrypsin phenotypes provides no evidence of an inherited susceptibility to alcoholic pancreatitis.

Acute Disease↗
PubMed1990

Vibrio infections in Kansas City.

In August 1989, the Kansas City Health Department declared vibrio infections a reportable disease. The authors present a report discussing cases of vibriosis reported between 1980 and 1989.

Adult↗
PubMed1990

Both ethanol consumption and protein deficiency increase the fragility of pancreatic lysosomes.

Both ethanol abuse and protein deficiency result in pancreatic injury. Moreover, these two variables frequently coexist. As lysosomal enzymes may play a role in the initiation of pancreatic injury, the aim of this study was to determine the effects of ethanol consumption and protein deficiency on pancreatic lysosomal stability. For 3 weeks, male Sprague-Dawley rats were match-fed (in groups of four) isocaloric amounts of one of the following liquid diets: (1) protein-sufficient diet, (2) protein-sufficient diet containing ethanol as 36% of the total energy, (3) protein-deficient diet, and (4) protein-deficient diet containing ethanol as 36% of energy. Pancreatic lysosomal stability was assessed by determining (a) latency, as indicated by the percentage increase in lysosomal enzyme activity in pancreatic homogenate induced by Triton X-100, and (b) by the percentage of lysosomal enzyme remaining in the supernatant after sedimentation of the lysosomal pellet from the pancreatic homogenate. Protein deficiency was associated with a decrease in latency and an increase in supernatant enzyme. Ethanol administration was associated with a decreased latency. Both protein-deficient and ethanol-fed animals exhibited higher pancreatic activities of cathepsin B, a lysosomal protease capable of activating trypsinogen. In addition, protein-deficient animals exhibited higher pancreatic activities of acid phosphatase, N-acetyl-glucosaminidase, and beta-glucuronidase. As lysosomal enzymes are postulated to play a role in the initiation of pancreatitis, these results suggest that ethanol consumption and protein deficiency may at least partly exert their toxic effects on the pancreas by altering pancreatic lysosomal stability and increasing the glandular content of cathepsin B.

Acetylglucosaminidase↗
PubMed1989

Maggiemycin and anhydromaggiemycin: two novel anthracyclinone antitumor antibiotics. Isolation, structures, partial synthesis and biological properties.

Two new anthracyclinone antitumor antibiotics, maggiemycin (6, NSC-D344012) and anhydromaggiemycin (8) have been isolated from a culture of an unspeciated Streptomyces (ATCC No. 39235). Bioautography against Bacillus subtilis was used for the preliminary detection of these anthracyclinones. Structures were proposed based on their UV-visible, IR, 1H NMR, 13C NMR spectra, electron impact (EI) and high-resolution EI-MS and confirmed by partial synthesis and a direct correlation with epsilon-rhodomycinone. Both the anthracyclinones are active against KB, P388 and L1210 murine tumor cell lines; however, anhydromaggiemycin was more active than maggiemycin. A number of related anthracyclinones have also been prepared and their biological activity has been determined. The structure-activity relationship of these new anthracyclinones is also discussed.

Animals↗