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Biomedical subjects

J K John

Publications and source records attributed to J K John.

25 records · Page 2Linked to original sources
PubMedDate not supplied

Self-injurious behaviour: a kindling phenomenon?

Self-injurious behaviour continues to be a drain on the resources for rehabilitation of the children with developmental disabilities. Pathogenesis and therapy seems fragmentary, with virtually every major neurotransmitter system being identified as the putative substrate for self-injurious behaviour. This phenomenon as it cuts across the diagnostic boundaries, although it is suggestive of a heterogeneous neurochemical basis, should call for the exploration of the biological event preceding the neurochemical cascade resulting in the behaviour. The authors argue that kindling is the preceding neurophysiological event resulting in self-injurious behaviour and, thus, can be effectively prevented pharmacologically.

Child↗
PubMedDate not supplied

Development of a hybrid artificial pancreas with a dense polyurethane membrane.

We have synthesized a series of strong, elastomeric polyurethaneureas and have used them to fabricate non-porous film and hollow fiber membranes. The solvent cast membranes are non cytotoxic, angiogenic, and permeable to gases, nutrients, secretagogues, and cell products via purely concentration driven transport. Permeability to water, glucose, and protein increases monotonically with membrane water absorption above a threshold value. Water absorption increases with soft segment hydrophilicity, soft segment molecular weight, and soft segment volume fraction of the (dry) segmented polyurethanes. Cell lines (RAJI and MOPC-31C) and primary cells (porcine islets) contained within our membranes have been maintained in culture for up to 6 months with nutrients supplied only by the external media. Cells within membrane devices were protected from immune rejection when implanted into murine hosts. Simple, compact devices containing porcine islets restored normoglycemia and near normal response to glucose tolerance tests in diabetic mice for at least 2 months. Explants had a high degree of vascularization adjacent to the membrane, with little or no fibrous tissue. These properties, and the material's ability to support cell function and protect xenogeneic cells from immunologic rejection, suggest that it would be useful in the construction of hybrid artificial organs and in in vitro cell culture.

Animals↗
PubMedDate not supplied

Psychiatric morbidity among dermatology inpatients.

BACKGROUND: Research on psychiatric morbidity among patients with dermatological diseases generally focuses on outpatients and questionnaire-based surveys. The aim of this study was to determine the prevalence and nature of psychiatric morbidity among dermatological inpatients with diagnosis being made by psychiatric interview, and ascertain whether demographic and clinical details in dermatological inpatients with psychiatric morbidity differed from those without it. METHODS: Charts of all inpatients admitted by the dermatology department between 1 January 1991 and 31 July 1995 were analysed for socio-demographic data, clinical features, treatment and course in hospital. For those patients who were referred to a psychiatrist, all records of the psychiatric consultation were obtained and analysed. RESULTS: A total of 1073 patients were admitted during the study period. Ninety-eight patients (9%) were diagnosed to have a psychiatric illness. Patients with psychiatric illness were likely to have had more admissions and longer duration of hospital stay. The most common psychiatric diagnoses were depressive episodes (34%) and adjustment disorders (29%). The highest rates of psychiatric morbidity were found among patients with chronic urticaria, exfoliative dermatitis and sexually transmitted diseases, including human immunodeficiency virus infection. The prevalence of psychiatric disorders was significantly higher in those who had received long term (more than six weeks) treatment with high-dose steroids (more than 1 mg/kg body weight of prednisolone). CONCLUSION: Some dermatology inpatients have psychiatric morbidity, which affects the course of the dermatological condition as well as the duration of hospitalization. The availability of psychiatric consultation at dermatology clinics and regular liaison between psychiatrists and dermatologists are essential for appropriate management.

Adjustment Disorders↗