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Biomedical subjects

J Kerr

Publications and source records attributed to J Kerr.

At least 19 recordsLinked to original sources
PubMed1992

Behavioural toxicity of antidepressants with particular reference to moclobemide.

The clinical decision to use a particular antidepressant should be made with reference to the behavioural toxicity profiles of substances in current use. Antidepressants can be cardiotoxic, proconvulsant, able to cause weight gain and sleep disturbance, and also impair psychological functions necessary for everyday living. Behavioural toxicity (reduction in psychomotor activity or cognitive ability) tends to augment levels of psychomotor and cognitive retardation; meta-analysis of controlled studies of antidepressants shows that some tricyclics can disrupt these functions. In comparison with these, moclobemide is relatively free from significant behavioural toxicity within the dose-ranges used. No relevant differences were found between placebo and 200 mg moclobemide on a battery of psychomotor and cognitive tests: with 400 mg, there was a significant impairment of peripheral reaction time, but no other measure of the test battery was impaired. In comparison, amitriptyline 50 mg, produced a noticeable and significant impairment of psychomotor and cognitive skills on most test measures. On the whole moclobemide has been found to be free from any behavioural toxicity likely to interfere with the well-being of patients or their performance of the tasks of everyday living.

Animals↗
PubMed1992

Specific and diversive curiosity and depression in junior high school students of divorced and nondivorced parents.

124 junior high school students (Grades 5 to 8) from a small school district in north central Kansas completed the Beck Depression Scale, the Maze test, and the Which-to-Discuss test. Background information, such as age, sex, grade, and marital status of parents, were also collected. There were no significant differences between boys and girls of divorced and nondivorced parents or across grades for scores on the Which-to-Discuss (specific curiosity) and depression, but boys scored significantly higher on the Maze test (diversive curiosity). No differences were noted between the students of divorced and nondivorced parents or across grades. Scores on Which-to-Discuss test and Maze test were not significantly correlated, but scores on one Maze test and depression correlated positively and significantly. When these students scored as more depressed, although in the normal range, they tended to score higher on diversive curiosity.

Attention↗
PubMed1992

Frequent loss of heterozygosity on chromosome 18 in ovarian adenocarcinoma which does not always include the DCC locus.

Inactivation of the DCC gene on chromosome 18 owing to loss of heterozygosity is a common finding in colorectal cancer. Because both ovarian and colon cancer are features of Lynch syndrome II, which has been provisionally mapped to chromosome 18, we hypothesized that loss of heterozygosity at the DCC locus may also occur in ovarian neoplasia. Fifty-two sporadic ovarian adenocarcinoma tumours were analysed by Southern blotting for loss of heterozygosity (LOH) at six chromosome 18 loci. Overall, tumours from 31 patients (60%) showed allelic loss at one or more of these loci. A similarly high level of LOH, 66%, was found at D17S5 (17p13.3). In contrast, moderate levels of LOH, of 31%, 39% and 33%, were found at MYCL1 (1p32), D1S57 (1p) and D14S20 (14q32.33) respectively. However, analysis of partial chromosome deletions in 11 patients indicates that the smallest region of overlap appears to exclude the DCC gene but to be between the D18S5 and D18S11 loci. This suggests that another locus, as well as or apart from DCC, may be involved.

Adenocarcinoma↗
PubMed1991

Effects of exercise and anion on intake of sodium solutions in Syrian hamsters.

Previous studies have shown that hamsters have low spontaneous intakes of NaCl solutions and are refractory to induction of salt appetite. In order to examine the generality of these results, the intakes of NaCl and NaHCO3 solutions are reported for hamsters housed either in normal laboratory conditions (sedentary) or with free access to exercise wheels. Spontaneous salt intakes, as well as those induced by acute sodium depletion and treatment with either the angiotensin converting enzyme inhibitor, enalapril, or deoxycorticosterone acetate (DOCA), were measured. The intakes of NaCl and NaHCO3 were similar. Salt intakes tended to be lower in exercising than in sedentary groups. Neither acute sodium depletion nor administration of enalapril increased salt intake systematically, but treatment with DOCA increased intakes of both salt and water. These results are contrasted with the efficacy of all three treatments to induce salt appetite in rats.

Aldosterone↗
PubMed1991

Detection of tuberous sclerosis in parents by magnetic resonance imaging.

We performed a detailed physical examination and MRI without gadolinium DTPA contrast in 60 couples with at least 1 child having tuberous sclerosis (TS). Eight parents had TS diagnosed by physical examination, family history, or various diagnostic procedures including MRI. Eight additional subjects and 6 control subjects had nonspecific high-signal white matter changes on MRI. MRI confirmed the diagnosis of TS in only 1 parent without physical findings of the disease, similar to the results of earlier studies using computed cranial tomography. CT may be less sensitive than MRI but is probably more specific for TS. Either CT or MRI may occasionally help substantiate the diagnosis of TS in a parent with few other findings. Both studies may need to be done in some parents to maximize the accuracy of genetic counseling.

Adult↗
PubMed1990

Sustained benefit of temporary limited reperfusion in skeletal muscle following ischemia.

Limiting the rate of reperfusion blood flow following prolonged ischemia in skeletal muscle has been shown beneficial. However, the persistence of this benefit with reinstitution of normal blood flow remains undefined. We investigated the role of temporary limited reperfusion on ischemia-reperfusion injury in an isolated gracilis muscle model in six anesthetized dogs. Both gracilis muscles were subjected to 6 hr of ischemia followed by 2 hr of reperfusion. Reperfusion blood flow was limited for the first hour in one gracilis muscle to its preischemic rate followed by a second hour of normal reperfusion (LR/NR). The contralateral muscle underwent 2 hr of normal reperfusion (NR/NR). Muscle injury was quantified by technetium-99m pyrophosphate (TcPyp) uptake and by histochemical staining using triphenyltetrazolium chloride (TTC) with planimetry of the infarct size. Capillary permeability was evaluated by muscle weight gain. Results are reported as the mean +/- SEM: [table: see text] These data demonstrate a sustained benefit from temporary limited reperfusion. This methodology should be considered in the surgical management of the acutely ischemic limb.

Animals↗
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↗