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Biomedical subjects

A J Watson

Publications and source records attributed to A J Watson.

At least 235 records · Page 13Linked to original sources
PubMed1985

Mucormycosis in renal transplant patients--a report of two cases and review of the literature.

Mucormycosis is a rare complication of diabetic ketoacidosis and immunosuppressed states, such as those occurring after renal transplantation. We describe two cases of mucormycosis in renal allograft recipients and present a review of similar cases previously reported. An analysis of these data suggests that renal transplant patients with concomitant diabetes mellitus are most susceptible to developing this complication.

Brain↗
PubMed1985

Cell proliferation in human colorectal mucosa in organ culture: the early adaptive changes.

In organ culture tissues undergo adaptive changes which complicate the assessment of proliferative indices. In the present study, a technique devised to preserve collagen metabolism and mesenchymal stroma in tissues of mixed origin was employed to investigate the kinetic behaviour of human colorectal mucosa over the first 24 hours in culture. During this period the structural preservation of tissue is good. The mitotic index in mucosa is profoundly depressed throughout the explants during the first 2-6 hours in culture. During this same period, however, heavy uptake of tritiated thymidine, indicating DNA synthesis, is observed within 150 micron of the cut edge of the samples but not centrally. This phenomenon has been described previously and assumed to be the result of inadequate diffusion of oxygen into the tissue. The 'edge labelling' phenomenon is followed by a wave of mitosis in the tissue edge at 8-18 hours in culture. This delay between tritiated thymidine uptake and the appearance of mitoses in the tissue edge may simply represent the duration of the S + G2 phase of the cell cycle, but is more likely to be due to cells in G1 moving into the S phase followed by cells hitherto blocked in G2 being stimulated into the M phase. After 18 hours the mitotic and labelling indices become more uniform throughout the samples suggesting that 'edge labelling' is partly due to local stimulation of cell proliferation by trauma rather than central inhibition due to diffusion problems. These results suggest that in this organ culture system, assessment of proliferative indices should be carried out after these adaptive changes have settled.

Adaptation, Physiological↗
PubMed1984

HLA typing in bartter syndrome.

The mode of inheritance of Bartter syndrome is unclear; however, autosomal recessive inheritance seems likely. A consistent genetic marker of the carrier state likewise remains elusive. HLA typing was done in a family in whom six of 12 sibs have the syndrome. No significant HLA-syndrome linkage was found. This is in contrast to another familial hypokalemic syndrome in which a significant HLA association was found.

Bartter Syndrome↗
PubMed1984

Morphological studies on the long-term organ culture of colonic mucosa from normal and dimethylhydrazine treated rats.

Mucosal explants were prepared from the colons of normal rats and from the non-neoplastic colonic mucosa of rats which had been treated chronically with the intestinal carcinogen dimethylhydrazine. They were maintained in an organ culture system which permitted survival up to at least 25 days. Morphological preservation of the mucosa was excellent up to 6 days in culture and thereafter changes began to occur. But even at 25 days normal crypt structures were still evident. The hyperplastic and dysplastic changes seen in pre-culture samples of DMH-treated mucosae remained recognisable during the first two days in culture. They were no longer seen in explants examined after this time however and, indeed, there appeared to be no difference in the morphology and survival of control and DMH-treated mucosae. It is possible that our culture system does not permit further neoplastic progression, but an alternative explanation is that the system discriminates specifically against the survival of neoplastic elements.

1,2-Dimethylhydrazine↗
PubMed1984

The intrarenal distribution of aztreonam in healthy and diseased kidneys: clinical therapeutic implications.

Using a healthy canine model, we evaluated the influence of renal physiological activity on the stability, intrarenal distribution, and clearance of aztreonam and compared the results with the concentrations of aztreonam that can be achieved in the scarred devitalized renal tissues of patients with end-stage kidney disease. Renal physiological activity significantly modulates the intrarenal distribution of aztreonam. During the production of maximally acid-concentrated urine, urinary aztreonam levels, clearance rates, and inner zone renal tissue concentrations are increased. Aztreonam concentrations in the parenchyma of severely diseased kidneys are significantly reduced in comparison with healthy tissues; nonetheless, the values are similar to concurrent serum drug levels, a result suggesting that treatment may provide adequate coverage for aztreonam-susceptible organisms.

Animals↗
PubMed1984

Morphometric and kinetic studies on the changes induced in the intestinal mucosa of rats by intraperitoneal administration of quinacrine.

The intraperitoneal administration of large doses of quinacrine in rats results in a state of enteromegaly affecting mainly the distal small bowel, caecum and proximal colon. This enteromegaly is associated with mucosal crypt hyperplasia, and hypertrophy and hyperplasia of the Muscularis propria. In order to investigate the changes in the intestinal mucosal crypts, morphometry and a metaphase-arrest experiment with vincristine were undertaken on a group of rats given 12 mg of quinacrine hydrochloride by intraperitoneal injection daily for 5 days 2 weeks previously, and comparisons drawn with a group of control animals. In the quinacrine-treated animals there was marked enteromegaly affecting the distal small bowel, caecum and proximal colon, and in these segments there was clear crypt hyperplasia. Proximal and distal to the dilated bowel hyperplasia was not seen. No consistent pattern of change in crypt-cell birth rate was evident. The mechanisms by which quinacrine may effect kinetic and morphometric changes in the intestinal crypts are considered.

Animals↗
PubMed1984

1-Deamino-8-D-arginine vasopressin as a therapy for the bleeding diathesis of renal failure.

The treatment of the bleeding diathesis of renal failure remains unsatisfactory. 1-Deamino-8-D-arginine vasopressin (DDAVP) has recently been shown to shorten the prolonged bleeding time of renal failure and may as a result diminish the risk of clinical hemorrhage. We describe 2 cases where DDAVP was used successfully in the management of hemorrhage in the setting of renal insufficiency.

Acute Kidney Injury↗
PubMed1984

Cure of cryptococcemia and preservation of graft function in a renal transplant recipient.

Disseminated cryptococcosis with cryptococcemia occurred in a renal transplant patient in whom immunosuppression was continued throughout antifungal therapy in an effort to ensure graft viability. Despite the initial presence of positive fungal cultures of blood, urine, and CSF, infection cleared rapidly, and there has been no evidence of recurrence. Throughout this period, renal function remained unaltered. This favorable outcome suggests that the prognosis for the renal transplant recipient with disseminated cryptococcosis may be improved.

Adolescent↗
PubMed1984

Are there diurnal fluctuations in crypt length and crypt cell birth rate in the intestines of normal and carcinogen-treated rats?

At eight time points over a period of 24 hours, crypt length (in cells) and crypt cell birth rate were measured by the stathmokinetic method with vincristine and evaluated at two sites in the small intestine and two in the colon in Wistar Porton rats. Normal animals were compared with animals which had received 24 injections, at weekly intervals, of the intestinal carcinogen 1,2-dimethylhydrazine. In the treated animals, crypts were significantly longer at sites prone to tumour formation but not at those sites known to be resistant to the effects of the carcinogen. In neither group of animals was there any significant fluctuation in mean crypt length over a 24 hours period. Crypt cell birth rates showed a considerable fluctuation. No difference was noted between normal animals and those treated with dimethylhydrazine and statistical analysis failed to confirm the presence of any true periodic fluctuation.

1,2-Dimethylhydrazine↗
PubMed1984

1-Deamino-8-d-arginine vasopressin (DDAVP): a potential new treatment for the bleeding diathesis of acute renal failure.

The treatment of the haemorrhagic tendency of acute renal failure remains unsatisfactory. To investigate a potential new therapy, 8 patients with acute renal failure and prolonged bleeding times received an infusion of 1-deamino-8-d-arginine vasopressin (0.4 microgram/kg). This resulted in significant shortening of the bleeding time at 1 and 2 hours post-infusion. The beneficial effect on bleeding time had largely disappeared by 8 hours. Pre-infusion Factor VIII activities were either within the normal range or mildly increased and a tendency to further elevation was noted post-DDAVP. In contrast, no alteration in platelet count or haematocrit was observed. No adverse effects were reported, and no significant change in heart rate, blood pressure or plasma osmolarity was noted.

Acute Kidney Injury↗
PubMed1983

Dw/LD-related molecular polymorphism of DR4 beta-chains.

The results of this study demonstrate the existence of molecular heterogeneity (polymorphism) within DR beta-chains isolated from a single serologically defined DR phenotype, DR4. The data are consistent with the possibility that this polymorphism is related to the Dw/LD phenotype as defined with the cellular reagents, homozygous typing cells.

B-Lymphocytes↗