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Biomedical subjects

C Kean

Publications and source records attributed to C Kean.

7 recordsLinked to original sources
PubMed2001

Identification of genes regulated by prolonged acid exposure in Helicobacter pylori.

To investigate the influence of prolonged acid exposure on the gene expression, transcripts of Helicobacter pylori, grown under pH 5.5 and pH 7.4 for five successive passages, were analysed by differential display PCR. Eight genes were regulated by prolonged acid exposure. These genes included topA, tufB, ureB, flaA, atoE in the H. pylori genome and a cDNA fragment with 54% identity of the predicted amino acid sequence to a Bacillus cereus YkoW protein. The remaining two cDNA fragments had no significant homology to known sequences. Our data suggest that most of these genes might be required for the resistance of H. pylori to prolonged acid exposure.

Acids↗
PubMed1985

Notes on the breeding of the WHHL rabbit: an animal model of familial hypercholesterolemia.

We describe in this study a reliable method for the breeding of the Watanabe heritable hyperlipidemic (WHHL) rabbit. Placing a male and a female WHHL rabbit in the same cage for the purpose of mating resulted in only two pregnancies out of a total of 227 mating attempts (0.9%). After manually assisting the rabbits, 15% of the matings resulted in pregnancies. When the female rabbits were injected with 40 I.U. of human chorionic gonadotropin within 1 hr of this procedure, 56% of the matings resulting in pregnancies. We feel that the inherent difficulty in breeding the WHHL rabbit, a model for the disease familial hypercholesterolemia, can be significantly overcome by the methods discussed in this report.

Animals↗
PubMed1982

Psoriasiform dermatosis in a rhesus monkey. Epidermal labeling indexes, polyamines, and histopathologic findings.

We have previously described the clinical and dermatopathologic features of a psoriasiform dermatosis in a rhesus monkey (Macaca mulatta). This animal has been studied further in attempts to characterize its skin disease. Epidermal cell DNA synthesis was measured following the intradermal injection of tritiated thymidine. Epidermal cell labeling indexes in the involved and uninvolved skin of the affected monkey and in the skin of a normal monkey were compared. The labeling indexes in the involved skin were significantly increased as compared with uninvolved skin; they were also significantly higher than in normal skin. Epidermal polyamine assays showed increased epidermal putrescine in involved skin together with increased spermidine and an increased spermidine-spermine ratio compared with uninvolved and normal skin sites.

Animals↗
PubMed1981

The metabolism of cis-dichlorodiammineplatinum (II): distribution, clearance, and toxicity.

The distribution and toxicity of 195mPt-labeled cis-platinum were studied in two groups of dogs. Serum and tissue levels, renal and marrow toxicities, and urinary excretion were compared in dogs given cis-platinum, 3 mg/kg, intravenously with a group treated by intraperitoneal administration. Peak serum levels occurred immediately after intravenous administration and 8 hours after intraperitoneal instillation, at which time the two were identical and declined at similar rates. Mean levels of cis-platinum measured in peritoneal tissues on day 4 were higher in the intraperitoneal group. Blood urea nitrogen, creatinine, and white blood cell and platelet counts were similar in both groups. Bloody ascites and adhesion formation occurred in 37.5% of dogs treated by intraperitoneal administration. The intraperitoneal route of chemotherapy administration results in higher drug levels in target peritoneal tissues without a corresponding increase in systemic toxicity.

Animals↗
PubMed1981

Psoriasiform dermatosis in a rhesus monkey.

We describe a dermatosis in a rhesus monkey (Macaca mulatta) that has the characteristic features of the human skin disease, psoriasis vulgaris. The monkey was affected by chronic erythematous, scaling plaques that occurred on the scalp, face, dorsal back, the extensor aspects of the limbs and the palms and soles. Subungual hyperkeratosis was present. Skin biopsies of the affected skin showed a regular acanthosis with reduction of granular cell layer, parakeratosis and supra papillary thinning of the epidermis. Foci of inflammatory cells were seen in the upper epidermis. The dermal changes were tortuous capillary loops and benign inflammatory infiltrate, particularly in the papillary dermis, all of which are features of the human skin disease psoriasis vulgaris. The presence of a nutritional deficiency syndrome was excluded and there was no evidence of any systemic disease.

Animals↗
PubMedDate not supplied

LDL, scavenger, and beta-VLDL receptors on aortic endothelial cells.

Primary and first passage aortic endothelial cells were shown to possess a high affinity receptor for beta-migrating very low density lipoproteins (beta-VLDL) distinct from the low density lipoprotein (LDL) receptor and scavenger receptor on these cells. In bovine aortic endothelial cells, 125I-rabbit beta-VLDL was taken up and degraded by a high affinity process that was competed for by unlabeled rabbit beta-VLDL and unlabeled postprandial VLDL from a fat-fed normal subject. However, unlabeled human or rabbit LDL, human LDL modified by malondialdehyde (MDA-LDL), or VLDL from a fasted normal human or a rabbit were not effective competitors for the degradation of 125I-rabbit beta-VLDL. In contrast to the receptor-mediated degradation of 125I-human or rabbit LDL and 125I-human-MDA-LDL, cell density did not affect the receptor-mediated degradation of 125I-rabbit beta-VLDL. Endothelial cells from a Watanabe heritable hyperlipidemic (WHHL) rabbit virtually did not degrade rabbit LDL, but degraded rabbit beta-VLDL at a rate equal to that seen in normal rabbit endothelial cells. It was concluded that the beta-VLDL receptor on endothelial cells is genetically distinct from the LDL receptor. Incubation of cells for 3 days with 100 micrograms/ml protein of unlabeled beta-VLDL caused an 88% increase in cellular cholesterol content, even though the beta-VLDL receptor activity was down-regulated by 60%. Endothelial cells and monocyte-macrophages are thus far the only cells known to possess the LDL receptor, the scavenger receptor, and the beta-VLDL receptor.

Acetates↗