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Biomedical subjects

J R Cole

Publications and source records attributed to J R Cole.

At least 19 recordsLinked to original sources
PubMed1992

Specific deuteration of dichlorobenzoate during reductive dehalogenation by Desulfomonile tiedjei in D2O.

Desulfomonile tiedjei DCB-1 is a strict anaerobe capable of reductively dechlorinating meta-chlorobenzoates. To probe the mechanism of this aryl dechlorination, we incubated cell suspensions of D. tiedjei in D2O and with 2,5-dichlorobenzoate. The deuterium was incorporated into the dechlorination product exclusively at the position of dehalogenation, as shown by gas chromatography-mass spectrometry and proton magnetic resonance analyses. These results favor a model for dechlorination that should not allow proton exchange at other positions, as would be the case if partial ring reduction occurred.

Bacteria, Anaerobic↗
PubMed1992

Invasion of enterocytes in cultured porcine small intestinal mucosal explants by Salmonella choleraesuis.

Porcine small intestinal explants maintained in vitro were inoculated with Salmonella choleraesuis to study the characteristics of its invasion of enterocytes. The explants were fixed at selected intervals for up to 12 hours after inoculation and examined by conventional light microscopy, immunoperoxidase staining, and transmission electron microscopy. Although there was diffuse loss of villous enterocytes during the first hour of incubation, the villi were reepithelialized by the end of 2 hours of culture, and the mucosal epithelium remained intact and appeared to be viable through 12 hours of culture. Intraepithelial S choleraesuis were not detected before 6 hours after inoculation, but after 12 hours of incubation, bacteria were numerous within enterocytes. Ultrastructurally, penetration of the brush border by S choleraesuis resulted in focal loss of microvilli. Bacteria were endocytosed into membrane-bound vacuoles where most remained, but a few were free within the cytoplasm of enterocytes. Invasion of the explants closely resembled that described for live animal and cell culture models of Salmonella spp invasion.

Animals↗
PubMed1991

Comparison of a veterinary breakpoint minimal inhibitory concentration system and a standardized disk agar diffusion procedure for antimicrobic susceptibility testing.

The correlation between the antimicrobic standard disk agar diffusion procedure and a veterinary antimicrobic breakpoint minimal inhibitory concentration system was evaluated. Bacterial isolates representing 5 different genera were tested against 15 antimicrobics. There were 3,795 tests performed; 77.3% of the test results were in agreement, 22.6% were in disagreement. Thirty-one percent of the conflicting results were due to the organism being intermediate on the standard disk agar diffusion procedure. Results suggest that the breakpoint system needs more than 1 antimicrobic dilution per antimicrobic, or a change in some of the single dilutions in the breakpoint system would eliminate some of these discrepancies. Another possibility would be to utilize more than 1 panel design, i.e., 1 for gram-positive organisms, 1 for gram-negative organisms, and 1 for fastidious organisms.

Anti-Bacterial Agents↗
PubMed1991

Culture and morphologic features of small intestinal mucosal explants from weaned pigs.

Small intestinal explants from weaned pigs were cultured under a variety of conditions. Explants maintained villus-to-crypt ratio between 1:1 and 1.5:1 for 48 hours. The mucosal epithelium remained well preserved and retained good cellular morphologic features, as determined by light and electron microscopy. Between 48 and 72 hours, considerable mucosal degeneration was evident. Best results were obtained when the explants were cultured on a rocking platform placed in an atmosphere of 95% O2 and 5% CO2, using supplemented RPMI 1640 cell culture medium.

Animals↗
PubMed1990

Pulmonary edema and hydrothorax in swine produced by fumonisin B1, a toxic metabolite of Fusarium moniliforme.

Pulmonary edema and hydrothorax were observed in mature swine that died approximately 5 days after consuming corn screenings. These postmortem observations were reproduced in younger swine (16-24 kg) that died within 1 week when fed the corn screenings under experimental conditions. Additionally, pulmonary edema and hydrothorax occurred in a pig (7.1 kg) that died after receiving 4 daily intravenous injections of fumonisin B1. A fungus was isolated from the corn screenings that is identical to Fusarium moniliforme MRC-826 in colony morphology and under microscopic examination.

Animal Feed↗
PubMed1978

Odoratin and paucin: cytotoxic sesquiterpene lactones from Baileya pauciradiata (Compositae).

An ethanol extract of Baileya pauciradiata exhibited cytotoxic activity against the human epidermoid carcinoma of the nasopharynx and the lymphocytic leukemia test systems. Two constituents responsible for this activity were isolated and identified as odoratin and paucin. Their identities were proven by IR, PMR, and mass spectral data; elemental analysis; preparation of their acetates; and melting-point determinations. Odoratin was confirmed by comparison with an authentic sample.

Animals↗
PubMed1977

Cytotoxic and tumor inhibitory agent from Polygala macradenia Gray (Polygalaceae): 4'-demethyldeoxypodophyllotoxin.

The chloroform fraction of Polygala macradenia exhibited activity against the P-388 lymphocytic leukemia and human epidermoid carcinoma of the nasopharynx test systems. The constituent responsible for this activity was a lignan, 4'-demethyldeoxypodophyllotoxin (C21H20O7). The identity was proven by elemental analysis; PMR, IR, mass spectrometric, and melting-point determinations; and preparation of a derivative.

Animals↗
PubMed1977

Cytotoxic agents from Michelia champaca and Talauma ovata: parthenolide and costunolide.

The ethanol extract of Michelia champaca and the petroleum ether extract of Talauma ovata showed activity toward the human epidermoid carcinoma of the nasopharynx test system. The active constituents were sesquiterpene lactones, identified as parthenolide (C15H20O3) and costunolide (C15H20O2). Their identities were proven by elemental analyses, PMR, IR, and mass spectral data, melting-point and mixed melting-point determinations, and comparisons with authentic samples and spectra.

Antineoplastic Agents, Phytogenic↗
PubMed1977

Cytotoxic agents from Bursera morelensis (Burseraceae): deoxypodophyllotoxin and a new lignan, 5'-desmethoxydeoxypodophyllotoxin.

The isolation and identification of deoxypodophyllotoxin and a new lignan, 5'-desmethoxydeoxypodophyllotoxin, from the dried exudate of Bursera morelensis (Burseraceae) are reported. Deoxypodophyllotoxin showed high activity in the KB and PS test systems; the new lignan, although highly active against the KB test system, demonstrated only marginal activity against the PS test system. A structure is suggested for the new lignan, which was named morelensin.

Animals↗