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Biomedical subjects

J Kerr

Publications and source records attributed to J Kerr.

At least 55 records · Page 3Linked to original sources
PubMed1989

Effect of mechanical stress on cellular morphology.

Mechanical stress occurs within and between cells during embryogenesis, wound healing and in the repetitive processes performed by various muscles of the body and, therefore, an experimental system to study the effects of mechanical stress was needed. Effects of mechanical stress on cell cycle are documented elsewhere (Curtis and Seehar, 1978). This study intends to investigate whether mechanical stress affects the cellular morphology. Chicken heart fibroblasts were grown as 'Sail-Sheets' a situation that approximates the in vivo organization of cells and provides an appropriate material for studying the effects of mechanical factors. Sail-Sheets were stressed using a low-frequency sine-wave oscillator and a glass rod attached to a piezoelectric ceramic probe. Electron microscopy (both SEM and TEM) was carried out on both mechanically stressed and control cultures. It was found that low frequency mechanical stress (1.0 Hz) may result in a decrease in the number and size of microprocesses (m).

Animals↗
PubMed1989

Differential effects of the destruction of Leydig cells by administration of ethane dimethane sulphonate to postnatal rats.

Ethane dimethane sulphonate (EDS) is a cytotoxic drug that selectively destroys Leydig cells in adult testes. This study has examined the effect of a single injection of EDS on the Leydig cell populations present in the testes of rats aged 5, 10, or 20 days. Microscopic examination of the tissue demonstrated that the fetal Leydig cell population was destroyed at all ages, but that subsequent development of the adult population of Leydig cells was not affected. Whilst the destruction of the fetal Leydig cells in this acute phase of EDS on 5-day-old rats was accompanied by a decline in serum testosterone levels, there was no apparent effect on this hormone when EDS administered at 10 or 20 days of age, despite the destruction of fetal Leydig cells in these rats. The long-term effects of EDS on Day 5 of age resulted in proliferation of the intertubular tissue in which more Leydig cells were observed, but serum testosterone and testosterone levels in response to human chorionic gonadotropin stimulation in vitro were normal despite moderate or severe disruption of the seminiferous epithelium. These data show that the fetal Leydig cells of immature testes are sensitive to the cytotoxic effects of EDS in the adult, but the response of the testes differs depending on the age at which the drug is administered.

Aging↗
PubMed1988

Oestrogen sulfotransferase: molecular cloning and sequencing of cDNA for the bovine placental enzyme.

The female sex hormone, oestrogen, plays a central role in breast cell proliferation in both the normal and malignant state. It controls transcription from several genes, including that for the progesterone receptor, and in endometrial tissue, via this receptor, it controls the gene for the enzyme oestrogen sulfotransferase. This enzyme may control the level of the oestrogen receptor by sulfurylating free oestradiol. To study the mode of transcriptional control exercised by oestrogen, bovine oestrogen sulfotransferase cDNA has been cloned and the nucleotide sequence determined. The message, of which 1812 bases have been sequenced, contains an open reading frame of 885 bases which encode a protein of 295 amino acids and a maximum apparent molecular weight of 34,600. The deduced protein sequence is supported by existing peptide sequence data and appears to contain a steroid-binding region. Some physico-chemical characteristics of the enzyme appear to differ markedly from those previously reported.

Amino Acid Sequence↗
PubMed1986

Endocrine and exocrine pancreatic function in treated coeliac disease.

Pancreatic function was assessed prospectively in a group of 18 treated adult coeliac patients, most of whom were asymptomatic. The para-aminobenzoic acid (PABA) test indicated exocrine pancreatic insufficiency in three patients, all of whom had persisting gastrointestinal symptoms. Arginine, 5 g intravenously, was used to stimulate pancreatic islet cells; basal and stimulated concentrations of plasma insulin, C-terminal glucagon, N-terminal glucagon, and blood glucose did not differ from asymptomatic nondiabetic control subjects. After gluten withdrawal, coeliac patients who responded clinically had no evidence of significant pancreatic impairment, but consideration of exocrine pancreatic insufficiency is worthwhile in those patients with persisting symptoms.

4-Aminobenzoic Acid↗
PubMed1982

Graft rejection in sponges. Genetic structure of accepting and rejecting populations.

Graft rejection frequencies in a population of the sponge Ectyoplasia ferox are reported in relation to the complexity of the histocompatibility system in this species. The frequency of graft acceptance is high but we show that, despite assumptions in the literature to the contrary, this does not imply that sponges accepting each other's grafts are genetically identical. This paper reports that graft-accepting pairs of sponges can have dissimilar plasmalemmal proteins. In addition, a theoretical analysis is presented of the types of histocompatibility systems that would account for the present results and those of others. We concluded that there is no evidence that sponges have highly polymorphic histocompatibility systems. The paper also reports on the histology of graft rejection and discusses some of the ecological relevance of the findings.

Alleles↗
PubMed1980

The families of borderlines. A comparative study.

The families of 12 carefully diagnosed patients with borderline personality disorder are compared with the families of both paranoid schizophrenic patients and patients with neurotic personality disorders. The families of the borderline patients were distinguished by the rigid tightness of the marital bond to the exclusion of the attention, support, or protection of the children. This pattern of neglect conforms to one theme in the clinical literature, and its implications for understanding and treating borderline patients are discussed. Limitations in the research methodology make the conclusions from this study tentative, but the results suggest new areas in need of research attention.

Adolescent↗
PubMed1979

Intracranial compliance during the post-operative period after surgery for intracranial aneurysms.

Generalised post-operative cerebral vasospasm is a major factor in delineating poor operative results following direct ruptured intracranial aneurysms. Continuous monitoring of intracranial pressure seems to be particularly helpful on such occasions, and intracranial compliance determination as well. High intracranial compliance values suggest that even small intracranial volume increases may induce rapid intracranial pressure and situations likely to produce neurological deterioration.

Humans↗
PubMed1978

Optimization of stimuli for trit-anomaloscopy.

Free-choice colour matches were made by 50 young normal trichromats on an anomaloscope. Six equations, of the kind 'blue' + 'green' = 'cyan' + 'yellow', were used in which the stimuli were defined by narrow-band well blocked interference filters. The stimuli were selected so that the instrument controls, which varied the quantities (blue/green), (cyan/yellow) and (cyan + yellow), were nearly independent controls for hue, saturation and brightness respectively. 'Yellow', 'green' and 'cyan' were fixed at 589, 499 and 480 nm, respectively, and the least interindividual variation in blue/green was found for 'blue' in the region 430-439 nm. This and a similar finding in the pilot study of Moreland and Young agree with expectations based on the density spectrum for macular pigment measured by Ruddock. Matches made by a few selected subjects, when the saturation control was locked at a position for the population mean, in the presence of large but typical saturation differences, were the same as when all three controls were used.

Adult↗