Search PubMed⌕ Search

Biomedical subjects

C Matthews

Publications and source records attributed to C Matthews.

85 records · Page 5Linked to original sources
PubMed1975

Heteropolypeptides from poly-alpha-cyanoglycine and hydrogen cyanide: a model for the origin of proteins.

Poly-alpha-cyanoglycine, a homopolymer synthesized from the N-carboxyanhydride of alpha-cyanoglycine, is converted by cumulative reaction of hydrogen cyanide to heteropolypeptides that can be hydrolyzed to protein amino acids, including glycine, alanine, valine, aspartic acid, and glutamic acid. These results are consistent with the hypothesis that the original heteropolypeptides on the earth arose spontaneously from hydrogen cyanide and water without the intervening formation of alpha-amino acids.

Chemical Phenomena↗
PubMed1975

Myopathy in experimental uremia.

M. quadriceps and diaphragm were studied in Wistar rats 2, 3, und 4 weeks after 5/6 nephrectomy. Control animals were sham operated and pair fed. In 10 mu transverse cryostat sections, the following histochemical reactions were performed: NADH-dehydrogenase, myofibrillar ATP-ase, modified trichrom stain, hematoxylin-eosin. Three fibre types (I, II, intermediate) were analysed quantitatively by planimetry. Sarcolemnal nuclei per unit area and fibre cross section area were determined. In muscle specimens from uremic animals, a uniform atrophy of all three fibre types could be demonstrated. In contrast to findings in man, preferential atrophy of one of the three fibre types, increase of sarcolemnal nuclei per fibre cross section area or structural abnormalities within single muscle fibres could not be detected. Neurogenic damage could be excluded (electrophysiology, sciatic nerve planimetry). The fibre changes point to a primary disturbance of muscle metabolism.

Adenosine Triphosphatases↗
PubMedDate not supplied

Dose-response effects of atropine and HI-6 treatment of organophosphorus poisoning in guinea pigs.

HI-6 (1-2-hydroxyiminomethyl-1-pyridino-3-(4-carbamoyl-1-pyridino -2- oxapropane dichloride) has been evaluated as an oxime alternative to pralidoxime, and toxogonin in the treatment of organophosphorus (OP) poisoning. The dose response effects of atropine (ATR) and HI-6 were investigated to more fully explore the interaction of these compounds in the treatment of OP poisoning. ATR, HI-6 and various combinations of the two drugs were evaluated against lethal poisoning by soman (GD) and tabun (GA) in guinea pigs. The effect of adjunctive diazepam treatment on the efficacy of atropine and HI-6 against soman was also investigated. Animals of either sex were challenged s.c. with OP and treated i.m. 1 min later with ATR and/or HI-6. When used, diazepam was injected immediately after ATR+HI6. LD50s of each treatment were calculated from probit models based on 24-hour survival against 5 levels of nerve agent and 6 animals per challenge level. A protective index (PI) was calculated by dividing the nerve agent LD50 in the presence of treatment by the LD50 in the absence of treatment. Treatment with HI6 alone had little effect on the toxicity of either OP. Treatment with ATR alone was more effective than HI-6 alone and was significantly more effective against soman than against tabun. When used in combination atropine and HI-6 had a strong synergistic effect against both agents. The dose of atropine used with HI-6 was critical in determining the efficacy of HI-6 against either agent. The slopes of the dose-lethality curves were minimally affected by the dose of ATR or HI-6. Adjunctive treatment with diazepam enhanced the efficacy of HI-6 and atropine against soman. It is concluded that 1) ATR has a large effect on the efficacy of HI-6 against OP poisoning, 2) the dose of ATR must be carefully selected in studies investigating the efficacy of HI-6 against OP poisoning, 3) the effective dose of ATR in the guinea pig is approximately 16 mg/kg, and 4) diazepam is a useful adjunct to atropine and HI-6.

Animals↗
PubMedDate not supplied

Radiation sensitivity of human malignant lymphocytes.

A simple and rapid in vitro technique to assess the sensitivity of human malignant lymphocytes to roentgen irradiation is described. A variety of established malignant lymphocyte cell lines were cloned in microwells and clone survival was used as the end-point. The survival of the clonogenic malignant lymphocyte down to a fraction of approximately 0.001 could be measured accurately. Except for a T-cell line, the radiation sensitivities of the cell lines were similar to that of normal T-lymphocytes.

Cell Line↗