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Biomedical subjects

A Russell

Publications and source records attributed to A Russell.

At least 19 recordsLinked to original sources
PubMed1992

Effect of selenium deficiency on hepatic type I 5-iodothyronine deiodinase activity and hepatic thyroid hormone levels in the rat.

Selenium deficiency in rats for a period of up to 6 weeks inhibited both the production of 3,3',5-tri-iodothyronine (T3) from thyroxine (T4) (5'-deiodination) and also the catabolism of T3 to 3,3'-di-iodothyronine (5-deiodination) in liver homogenates. The hepatic stores of T3 were decreased by only 8% in selenium deficiency, despite the T3 production rate from T4 being only 7% of the rate found in selenium-supplemented rats. Hepatic glutathione S-transferase (GST) activity was increased in both hypothyroidism and selenium deficiency, but apparently by different mechanisms, since mRNA expression for this family of enzymes was lowered by hypothyroidism and increased in selenium deficiency. It is concluded that, since both T3 production and catabolism are inhibited by selenium deficiency, there is little change in hepatic T3 stores, and therefore the changes in the activity of certain hepatic enzymes, such as GST, that are found in selenium deficiency are not the result of tissue hypothyroidism.

Animals↗
PubMed1992

Diagnosis and management of the tethered cord syndrome.

Tethering of the spinal cord can occur from a thickened filum terminale, scarring due to myelomeningocele repair, lipomas or diastematomyelia. The typical presentation is a lumbar cutaneous defect, enuresis, unexplained back or leg pain, foot deformities, leg length discrepancies or scoliosis. Spinal ultrasound in neonates and MRI in older children offers ready diagnosis. With laser and microneurosurgical techniques, repair of these defects is safe and effective. The authors recommend that any infant having a mid-line lumbar cutaneous abnormality, such as a hemangioma, lipoma, hair patch or dimple, be evaluated to rule out tethering of the spinal cord.

Child↗
PubMed1991

Who eats what? A comparison of dietary patterns among men and women in different occupational groups.

Dietary data were obtained during a community-based study of risk factors for heart disease in 1983. Results were compared for men and women in broadly defined socioeconomic groups based on occupation and education. People in higher status occupation groups and with more education, and women more than men, had food consumption patterns more consistent with current health promotion messages. For example, they reported eating more wholemeal or brown bread and more fresh fruit and vegetables, drinking more skim or low-fat milk, eating fewer eggs and having less sugar in hot drinks or on cereals. There was some evidence, however, of an interplay of influences of cost and health awareness. For example, retired men were less likely than employed men to eat butter, cream, fresh fruit and vegetables, while men in the upper socioeconomic groups reported relatively higher consumption of butter and cream. The results emphasise the need for a range of strategies aimed at specific subgroups in order to improve national dietary patterns in Australia.

Adult↗
PubMed1990

Primary renal carcinoid.

A case of primary renal carcinoid in a 34-year-old man is reported. The lesion was morphologically identical to carcinoid tumors arising in the gastrointestinal or respiratory tracts. The renal carcinoid was focally argyrophilic and contained chromogranin and neuron-specific enolase disclosed by immunohistochemical studies. The diagnosis was further confirmed by membrane-bound cytoplasmic neurosecretory granules visualized by electron microscopy. The possible histogenesis of this unusual tumor and a review of the literature are discussed.

Adult↗
PubMed1989

HLA-Bw60 increases susceptibility to ankylosing spondylitis in HLA-B27+ patients.

We examined the distribution of non-B27 alleles of the HLA-B locus among B27+ patients with ankylosing spondylitis (AS), to detect any additional HLA-B locus allele(s) that may act in conjunction with B27 to increase susceptibility to AS. HLA-Bw60 (or B40 when the Bw60,61 split of B40 was not typed for) was shown to be increased among B27+ AS patients in each of 5 independent data sets. This increase was statistically significant in 4 of the 5 data sets studied, and the overall significance was P less than 0.00001. Susceptibility to AS in B27+ individuals was further increased by a factor of approximately 3 when Bw60 was also present. The distribution of HLA-A alleles on the B27-bearing haplotypes in AS patients was not significantly different from that in normal controls. On the other hand, the distribution of HLA-A alleles on Bw60-bearing haplotypes was significantly different from the distribution of A alleles on Bw60 haplotypes in the general population (P less than 0.0005). Bw60 was not increased in B27- patients with AS. A dominant mode of inheritance generally fits AS; however, our sib pair analysis indicates that the B27,Bw60 disease subgroup follows a more recessive mode of inheritance.

Alleles↗
PubMed1989

Conductive education--magic or myth?

Subjective reports on the results of conductive education (CE) in 18 groups of children in English schools, and in 16 children who had been to Hungary were examined. Although many improvements seem to be indicated, rigorous scientific methods were not used, and the verdict on CE must remain open. The newly established Foundation for Conductive Education in Birmingham may help to resolve current uncertainty.

Activities of Daily Living↗
PubMed1989

Positron emission tomography of the cerebellum in autism.

On the basis of neurological evidence that autistic patients have fewer Purkinje and granule cells in the cerebellum as well as vermal cerebellar hypoplasia, the authors tested the hypothesis that autistic patients have cerebellar hypofunctioning. They used positron emission tomography of the cerebellum with 18F-labeled 2-deoxyglucose to study seven autistic patients and eight age-matched control subjects. The results showed no significant difference in mean cerebellar glucose metabolism between the two groups, but all mean glucose rates of the autistic patients were either equal to or greater than those of the control subjects. The implications of these findings are discussed.

Adult↗
PubMed1989

Neuropeptide Y in the sympathetic control of blood pressure in hypertensive subjects.

Neuropeptide Y (NPY) coexists with noradrenaline in postganglionic sympathetic neurons and with noradrenaline and adrenaline in the central nervous system. The possibility that NPY is released into the circulation during activation of the sympathoadrenal system was investigated in ten moderately hypertensive volunteers using three different stimuli. In healthy moderately hypertensive volunteers cold pressor test, head up tilt and graded bicycle exercise resulted in increased blood pressure, heart rate and plasma catecholamine concentrations. While there was a trend for plasma NPY-like immunoreactivity (NPY-LI) to increase during cold pressor test and head up tilt, NPY-LI concentration only increased significantly during bicycle exercise, the stimulus of greatest duration. These results suggest that plasma NPY-LI can be released into the circulation on sympathoadrenal activation in moderately hypertensive subjects and demonstrate that the pattern of release is similar to that previously observed in normotensive subjects.

Adrenal Glands↗
PubMed1988

Reactive hyperemia in patients with Raynaud's phenomenon.

Our study was undertaken to demonstrate the efficacy of digital plethysmography using a strain gauge plethysmograph in the assessment of the reactive hyperemic response. We studied patients with Raynaud's phenomenon with and without associated connective tissue disorders. Reactive hyperemic response was examined in 27 normal subjects and 19 patients with Raynaud's phenomenon at 12-14 degrees C, 20-22 degrees C and 37-40 degrees C. In the normal subjects reactive hyperemia was greatest at 20-22 degrees C. In 19 patients with Raynaud's phenomenon, the pulse waves were smaller at 20-22 degrees C than in normal subjects and the response was seen in only 5 of 19 patients. At 12-14 degrees C reactive hyperemic response was usually absent and at 37-40 degrees C it was evident in 9 patients. Nifedipine was given to 11 patients (5 mg TID for 4 weeks) and in 10 of them, reactive hyperemic response was restored at 20-22 degrees C.

Adolescent↗
PubMed1987

Reduced estradiol production by a substituted triazole results in delayed ovulation in rats.

Ovulation in the rat is delayed by a single administration of the substituted triazole R151885 (1,1-di(4-fluorophenyl)-2-(1,2,4-triazol-1-yl)-ethanol). This delay results from a 24-hr shift in the preovulatory luteinizing hormone (LH) surge since administration of chorionic gonadotrophin on proestrus restores ovulation. Plasma levels of estradiol are markedly reduced (42-45%) 6-12 hr after administration of R151885. The restoration of ovulation in R151885-pretreated rats, by administration of exogenous estradiol benzoate, indicates that the reduced estradiol levels play a pivotal role in the delay of ovulation. Granulosa cells isolated from rat ovaries produce estradiol and progesterone in vitro in the presence of both follicle-stimulating hormone and testosterone. The addition of R151885 to such cultures results in a dose-dependent inhibition of estradiol production (69% by 1 microM) without a significant effect on progesterone production. This inhibition occurs at concentrations of R151885 similar to those measured in vivo. R151885 is a competitive inhibitor of human placental aromatase (apparent Ki with androstenedione substrate of 410 nM) and produces a type II spectral perturbation of cytochrome P-450 from placental microsomes. Pituitaries isolated from R151885-treated rats have reduced LH output in response to gonadotrophin-releasing hormone stimulation compared with those of controls. It is proposed that R151885 competitively inhibits aromatase activity in developing ovarian follicles. The resultant temporary reduction of plasma estradiol levels at a critical time in the estrous cycle, and consequent inadequate pituitary sensitization, produces a 24-hr delay in the preovulatory LH surge and hence ovulation is delayed by 24 hr.

Animals↗
PubMed1987

Direct radioimmunoassay of human plasma atrial natriuretic peptide in various normal and pathophysiological states: increase in renal and cardiac failure during exercise.

We have used a sensitive direct radioimmunoassay to study the effects of exercise on plasma atrial natriuretic peptide (ANP) concentrations in man. Plasma ANP concentration increased three-fold in sixteen patients undergoing bicycle ergometer electrocardiographic tests for the investigation of chest pain. Resting ANP concentrations were higher in those patients in whom there was more evidence of heart disease, such as a positive exercise test, treatment with a beta blocker or history of myocardial infarction, although exercise resulted in increased ANP in both groups. We also confirm the increased plasma ANP concentration observed in patients with congestive cardiac failure and renal failure. In nine patients with renal failure routine haemodialysis was accompanied by a 30 per cent reduction in plasma ANP concentration. Plasma ANP concentrations were similar in treated hypertensive patients, untreated borderline hypertensive patients and normotensive subjects.

Adult↗
PubMed1986

Evidence that the potential antipsychotic agent rimcazole (BW 234U) is a specific, competitive antagonist of sigma sites in brain.

Rimcazole (BW 234U) is a potential antipsychotic agent which in open-clinical trials appears to be effective in acute schizophrenic patients. In the present study, rimcazole was found to block the specific binding of [3H]-(+)-SKF 10,047 to sigma sites in rat and guinea pig brain (IC50 = 5.0 X 10(-7) M). The compound was 100 times weaker as a blocker of phencyclidine sites (IC50 = 4.3 X 10(-5) M). At 1 X 10(-5) M, rimcazole had only weak effects on mu, delta, kappa and epsilon opioid receptors. Scatchard analysis of the binding data from guinea pig brain revealed an apparent KD for [3H]-(+)-SKF 10,047 of 85 +/- 5 nM and a Bmax of 824 +/- 27 fmole/mg protein. In the presence of 5 X 10(-7) M BW 234U, the apparent KD was 165 +/- 35 nM, but the Bmax (892 +/- 146 fmoles/mg protein) was not affected. This suggests that rimcazole is a competitive inhibitor of sigma sites. The agent was also capable of blocking sigma sites in vivo (ID50 = 6 mg/kg i.p., mice) as judged by an in vivo sigma receptor binding assay. Thus, if the antipsychotic activity of rimcazole is confirmed in double-blind, placebo-controlled trials, it would be the first compound whose mechanism of antipsychotic activity may best be explained by a direct blockade of sigma sites and not by a direct blockade of dopamine (D2) receptors in brain.

Animals↗
PubMed1985

Adaptive abilities in nonclinical second-generation Holocaust survivors and controls: a comparison.

A nonclinical second-generation Holocaust survivor group of young adults is contrasted with a comparable North American Jewish control group. A discriminate analysis of questionnaire responses indicates specific differences between the functioning second generation (N = 68) and the control group (N = 51). Focus was on growth-producing rather than pathogenic factors. Sample characteristics, interview data, techniques of data analyses and results are presented and discussed; some literature and work in progress is noted. Recommendations regarding further research efforts are made.

Adaptation, Psychological↗
PubMed1984

Reflections on the current psychiatric consultation and referral pattern and on the state of the art, at Oxford Regional Centre, an adult mental retardation facility.

This paper investigates the utilization pattern of the psychiatric consultation and referral service provided by the author in an Adult Mental Retardation Facility over a three-year period. The services, their history and locale are described against a background of changes in attitudes towards the problems of the retarded. Rising interest by psychiatrists in the field is placed in context. A spectrum of variables is used for a statistical analysis of factors (Chi2) influencing psychiatric referrals or non-referrals of all new admissions over the period indicated (N = 98). Against a background of increasing normalization and de-institutionalization, the character and composition of the shrinking institutional population has changed. Administration and direct-care staff are now confronted with management and care problems of lower functioning retardates, presenting difficult-to-manage behaviours and severe, often multiple, handicaps. Several factors with resource and care implications are considered, affecting institutionalized as well as community placed retardates, especially in hard economic times. Findings are discussed; recommendations are made concerning the application of scarce psychiatric resources to meet changing psychiatric needs of the population, maximize services and continue community directed normalization efforts. Some caveats are sounded and further research suggested.

Adult↗
PubMed1983

Moral judgment in relation to behavioral and cognitive disorders in adolescents.

The capacity for formulating moral judgments shown by 20 emotionally disturbed, cognitively delayed adolescents was related to their social behaviors as observed in a classroom situation. Adolescents reported by their teachers to be shy and submissive were less capable of reasoning about moral issues than were adolescents who were seen as more assertive and socially engaged. The level of moral judgment was not a function of intelligence or ability to understand concrete operations. The implication that social engagement is a critical determinant of moral judgment for these adolescents is discussed.

Adolescent↗