Search PubMed⌕ Search

Biomedical subjects

J G Pounds

Publications and source records attributed to J G Pounds.

41 records · Page 3Linked to original sources
PubMed1978

The effects of Clostridium perfringens enterotoxin on rat and rabbit ileum: an electron microscopic study.

Intestinal epithelial damage caused by Clostridium perfringens enterotoxin in rats and rabbits was identified by light microscopy and compared at the surface (scanning electron microscopy), and the ultrastructural (transmission electron microscopy) levels. Under the light microscope damage to the epithelial layer of villus tips was clearly evident in cross-sections. Whole tissue viewed under the scanning electron microscope showed comparable tip localization of morpholigic damage in the form of collapsed tips and a dense covering of rounded blebs on the tips. Ulstructuctural observations included partial and sometimes complete disappearance of microvilli structures, budding of the terminal web region into the lumen, and even complete destruction of epithelial cells. These data suggest that C. perfringens enterotoxin attacks the epithelial cells with a preference for cells at the villus tips and causes damage at least in part by altering the cells' apical membranes. This then leads to cellular sloughing, death, and lysing.

Animals↗
PubMed1977

3,4,3',4'-tetrachloroazobenzene: a potential environmental toxicant.

3,4,3',4'-tetrachloroazobenzene (TCAB), a potential environmental toxicant formed in the industrial manufacturing and the microbial degradation of chloroanilide herbicides, has been prepared in 87% yield by an improved procedure. In vitro experiments with C3H/10T1/2 cells have shown that TCAB is toxic to mammalian cells, which may be correlated with observable cytological changes. TCAB has also been found to be weakly mutagenic by the Salmonella/microsome test. In addition, C3H/10T1/2 cells are transformed following a ten day incubation with TCAB. These data suggest the potential health hazard associated with the environmental occurrence of TCAB.

Animals↗
PubMedDate not supplied

An X-ray microprobe facility using synchrotron radiation.

An X-ray microprobe for trace elemental analysis at micrometer spatial resolutions, using synchrotron radiation (SR), is under development. The facility consists of two beamlines, one including a 1:1 focusing mirror and the other an 8:1 ellipsoidal mirror. At present, "white light" is used for excitation of the characteristic X-ray fluorescence lines. Sensitivities in thin biological samples are in the range of 2-20 fg in 100 microns2 areas in 5 min irradiation times. Scanning techniques, as well as microtomography and chemical speciation, are discussed. Application to a specific biomedical study is included.

Animals↗
PubMedDate not supplied

Potentiation of chlorinated hydrocarbon toxicity by 2,5-hexanedione in primary cultures of adult rat hepatocytes.

Primary cultures of adult rat hepatocytes were used to investigate potentiation of halocarbon-induced hepatotoxicity by aliphatic ketones. Male Sprague-Dawley rats were pretreated with corn oil or 2,5-hexanedione (HD; 15 mmol/kg, po) in corn oil. Eighteen hours later the hepatocytes were isolated and cultured in Williams' Medium E and exposed to several concentrations of the hepatotoxicants carbon tetrachloride, chloroform, deutero-chloroform, or 1,1,2-trichloroethane. The cytotoxicity of these halocarbons as measured by release of the cytosolic enzyme lactate dehydrogenase into the culture medium was both time- and concentration-dependent. Halocarbon-induced cytotoxicity was exacerbated in cells isolated from HD-pretreated rats with significant increases in LDH release over cells isolated from corn oil-pretreated rats. In addition, chloroform was significantly more toxic than deutero-chloroform in hepatocytes from either corn oil- or HD-pretreated rats. Primary monolayer cultures were useful for studying ketone-induced potentiation, halocarbon-induced hepatocellular toxicity, and the mechanisms by which these effects occur.

Animals↗