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Biomedical subjects

D Manning

Publications and source records attributed to D Manning.

54 records · Page 3Linked to original sources
PubMed1988

Characteristics of somatostatin desensitization in the pituitary tumor cell line AtT-20.

The molecular mechanisms of somatostatin (SRIF) desensitization were investigated in the anterior pituitary tumor cell line AtT-20. Previous studies have shown that pretreatment of AtT-20 cells with SRIF analogs desensitizes the cells to SRIF inhibition of hormone release, cyclic AMP formation and calcium influx. This desensitization may involve a change in the properties of the SRIF receptors. Pretreatment of AtT-20 cells with Trp8-SRIF reduced the binding of the SRIF analog [125I]CGP 23996 (des-Alal, Gly2-[desamino-Cys3, Tyr11]-3, 14-dicarbasomatostatin) to AtT-20 cell membranes. The loss of [125I]CGP 23996 binding was dependent on the time of Trp8-SRIF treatment and was reversible. The ability of GTP analogs to inhibit [125I]CGP 23996 binding was reduced after Trp8-SRIF treatment, suggesting that the SRIF receptor and the inhibitory G proteins become uncoupled during desensitization. This is indicated further by the decrease in SRIF stimulation of GTPase activity and SRIF inhibition of forskolin-stimulated adenylyl cyclase activity in desensitized membranes. The reduction and recovery of SRIF inhibition of adenylyl cyclase activity after Trp8-SRIF pretreatment has a similar time course as the changes in [125I]CGP 23996 binding. GTP inhibition of forskolin-stimulated adenylyl cyclase activity is also reduced in SRIF-desensitized membranes. The loss of the GTP effect occurs rapidly and does not fully recover after Trp8-SRIF pretreatment. The levels of ADP-ribosylation of inhibitory GTP binding protein, the relative quantity of the alpha subunits of the inhibitory G proteins and their electrophoretic mobility after 2-dimensional gel electrophoretic analysis, are not altered in SRIF-desensitized membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclase Inhibitors↗
PubMed1986

Metoclopramide-induced tardive dyskinesia: a case report.

A case of tardive dyskinesia developed in a patient who had been treated with metoclopramide for 8 months. Acute extrapyramidal side effects are also possible with this medication. Guidelines for the use of metoclopramide are presented with special emphasis on patients with renal insufficiency and the elderly. The importance of consultation-liaison psychiatrists' familiarity with the neurologic side effects of this commonly prescribed drug used in general medical practice is emphasized.

Aged↗
PubMed1985

Quantitative bacteriology of peripheral venous cannulae in neonates.

In a study of 50 peripheral venous cannulae removed from neonates in the special care baby unit, quantitative and qualitative techniques for cannula culture were compared and the results correlated with detailed clinical information. High-density colonization was demonstrated on the external and internal surfaces of nine, and on the external surface alone of four, cannula tips. Internal surface colonization was always associated with heavy external surface growth. In predicting high-density colonization by quantitative methods, qualitative culture in broth was 100% sensitive and 89% specific. There was a significant association between high-density colonization of the cannula tip and hub colonization, surrounding skin colonization, longer duration of cannula insertion, and slower average infusion rate. Similar organisms were isolated more frequently from the cannula tip and the hub than from the cannula tip and surrounding skin. These findings indicate that peripheral venous cannulae are a potential source of infection in neonates, that there is no advantage of techniques that identify internal surface colonization, and that most cannula tip infections have their origin in a colonized hub.

Bacteria↗
PubMed1978

Transplantation of cultured thymic fragments. I. Morphologic and technical considerations.

Thymic fragments were maintained in organ culture until egress or deterioration of the leucocyte component was near completion. These depopulated cultured thymic fragments were then implanted into immunologically competent mouse recipients. Acute immunologic rejection was not observed in mice given cultured thymic allografts. If the organ culture period was approximately 2 weeks, lymphoid repopulation and newly developed Hassall's corpuscles were observed 7-10 weeks after implantation. If the initial culture period was extended to 3 weeks, transplanted fragments developed as unusual repopulation pattern, characterized by eosinophils, macrophages and plasma cells. This finding could be interpreted as a protracted allograft rejection or, more likely, a loss of ability of the thymic epithelium to attract or differentiate the types of precursors usually attracted to the normal gland. When cultured and non-cultured tissues were simultaneously transplanted in a single recipient, the non-cultured tissue was acutely rejected and became fibrous, while the cultured thymus assumed the appearance of a normal lymphoid organ without any neighbouring inflammatory reaction.

Animals↗
PubMedDate not supplied

Chronic inflammatory bowel disease and the 'over-clean' environment: rarity in the Irish 'traveller' community.

The causes of ulcerative colitis and Crohn's disease are unknown. Current research is focused on genetic factors but environmental factors may also be important. Exposure to infections in early life is believed to reduce the incidence of bronchial asthma. We hypothesised that exposure to enteric bacteria and infections in early life may also reduce the incidence of idiopathic inflammatory bowel disease. Chronic inflammatory bowel disease may be a by-product of our over-clean environment. Social groups with poorer living standards might be expected to have a lower prevalence of this condition. The "traveller" or itinerant community in Ireland is one such group. We therefore attempted to estimate the prevalence of inflammatory bowel disease in the traveller population. Twenty five of 30 gastroenterologists or surgeons in Ireland responded to requests for information. None could recall ever seeing a "traveller" with idiopathic inflammatory bowel disease. While genetic factors cannot be excluded, a low prevalence of idiopathic inflammatory bowel disease would support the environmental hypothesis.

Chronic Disease↗