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Biomedical subjects

S Wilson

Publications and source records attributed to S Wilson.

At least 19 recordsLinked to original sources
PubMed1992

Chronic emesis caused by a nematode-induced gastric nodule in a cat.

A spirurid nematode-induced gastric nodule was believed to be responsible for chronic gastric irritation and vomiting in a domestic short-hair cat. Clinical improvement was noticed following surgical removal of the parasitic nodule in the wall of the pylorus. Morphologic characteristics of the parasite were most consistent with Spirocerca lupi. Infection with Spirocerca lupi is most commonly reported in Canids, often resulting in chronic granulomatous disease of the distal portion of the esophagus. In some animals, the lesions transform into fibrosarcomas and osteogenic sarcomas.

Animals↗
PubMed1992

T-cell receptor variable gene products and early HIV-1 infection.

To assess the hypothesis that the human immunodeficiency virus (HIV) might mimic major histocompatibility complex (MHC) allodeterminants and interact with T-cell receptors (TCRs) of alloreactive T-cells, we have done a preliminary analysis of the range of alpha beta TCR gene products in 16 HIV-1-seropositive individuals with normal CD4 counts and in 16 healthy HIV-1-negative controls. Using a panel of monoclonal antibodies with a two-colour direct immunofluorescence method, we found a significant increase in the expression of the V beta 5.3 subfamily in the HIV-positive patient group compared with controls (p less than 0.01). Selected increase in expression of V beta sequences has been described in various autoimmune conditions and our findings raise the possibility that the immunopathological damage from HIV infection may be due to the induction of autoreactivity. If HIV does mimic MHC II, the normal immune response to the virus could represent an autoimmune process similar to graft-versus-host disease.

Gene Expression↗
PubMed1992

The paired domain-containing nuclear factor pax[b] is expressed in specific commissural interneurons in zebrafish embryos.

The zebrafish paired box (Pax) genes are expressed in the early neural tube and are thought to be transcription factors that regulate the differentiation of cells in the central nervous system (CNS). The protein product of one of these Pax genes, pax[b], is detectable as a nuclear antigen in all the regions of the embryo that transcribe the gene including the posterior midbrain, the nephritic primordium, the Wolffian duct, the optic stalk, and, in specific neurons, in the hindbrain and spinal cord. The timing and pattern of axonal outgrowth by the early pax[b]-positive neurons suggest that they are the commissural secondary ascending (CoSA) interneurons in the spinal cord; the primary commissural interneurons (MiD2c and MiD3c) in hindbrain rhombomeres mi2 and mi3; and a previously unclassified set of commissural interneurons that we termed the commissural caudalrhombomere ascending (CoCaA) interneurons in the caudal hindbrain. In contrast, the Mauthner interneurons do not express pax[b] early in development. Shortly after the appearance of the first pax[b]-positive interneurons, additional nuclei adjacent to the first pax[b]-positive interneurons become pax[b] positive. This pattern of expression suggests that the pax[b] protein may be involved in determining the identity of specific commissural interneurons.

3,3'-Diaminobenzidine↗
PubMed1992

Thyrotropin-releasing hormone selectively reverses lorazepam-induced sedation but not slowing of saccadic eye movements.

To investigate preliminary reports that benzodiazepine-induced sedation may be reversed by thyrotropin-releasing hormone (TRH), we examined the effect of TRH or saline placebo on two variables which are sensitive to benzodiazepine agonists: changes in sedation and saccadic eye movements. Lorazepam 10 micrograms/kg i.v. increased self-ratings of sedation and reduced self-ratings of alertness and these changes were almost completely reversed by TRH. In contrast the slowing of saccadic eye movements by lorazepam was not reversed by TRH. The effects of TRH do not appear to be due to a direct antagonism at the benzodiazepine receptor, since flumazenil reverses changes in both variables. Moreover ligand binding studies reveal that TRH has very low affinity at this receptor. These clinical data provide the first demonstration that it is possible to distinguish between the effects of benzodiazepines on saccadic eye movements and psychological self-ratings.

Adult↗
PubMed1992

Effects of age, sex and housing on the trabecular bone of laying strain domestic fowl.

To determine the effects of age, sex and housing on trabecular bone volume, samples were collected from groups of male and female domestic fowl housed in cages or floor pens from four to 60 weeks old. Between 25 and 60 weeks old, trabecular bone volume decreased by 25 per cent in sections of free thoracic vertebrae (T5) from female birds, the loss occurring at an earlier age in caged birds. Over the sample period, TBV in male caged birds diminished by 35 percent, but male floor birds showed no reduction in trabecular bone volume. At 60 weeks, trabecular bone volume was 30 per cent greater in male caged birds and 40 per cent greater in male floor birds than in the corresponding females. In reproductively active females, no trabecular osteoid was observed, indicating no new trabecular bone formation. However, trabecular osteoid was present in two birds aged 60 weeks which had regressed ovaries. Osteomalacia was not seen in any of the bone samples.

Aging↗
PubMed1992

Estrogen receptor affinity and effects on MCF-7 cell growth of triarylethylene carboxylic acids related to tamoxifen.

The estrogen receptor binding, and growth suppressant and stimulating effects in MCF-7 human breast cancer cells, of four structural variants of the triarylethylene antiestrogen tamoxifen (1) were studied. In these analogs, the dialkylaminoethoxy side chain of 1 was replaced by carboxylic acid or oxyacetic acid substituents. The presence of a p-hydroxy group in the ring geminal to the one bearing the side chain resulted in ligands with estrogen receptor affinities greater than that of 1 but less than that of estradiol. Compared to 1, none of the test compounds were effective suppressants of cell growth. To the contrary, the phenolic oxyacetic acid analog effectively reversed the growth suppressive effect of 1. Also, it was as effective as estradiol, though less potent, in stimulating growth of cells grown in estrogen depleted medium, suggestive of full estrogen agonist activity. Its carboxylic acid counterpart had little or no effect on proliferation. Because the phenolic oxyacetic acid is a metabolite of 1 in animals, its estrogenicity may have therapeutic implications of concern, depending on the extent to which it is formed and distributed in tissues of patients receiving 1.

Animals↗
PubMed1992

Prevalence of spinal pain among the staff of a district health authority.

Being aware of the many neck and back problems which occur among staff, the departments of Occupational Medicine and Physiotherapy initiated a study to ascertain the scale of the problem among employees of the district health authority. A questionnaire was sent to a 10 per cent sample, stratified by occupation, of the 16,000 employees of a district health authority of which 84 per cent (1363) responded. Over half of all respondents had had a significant degree of spinal pain in the past year, mainly located in the back. In over half of those with pain, their discomfort had been significant enough to interfere with sport, work and sleep. Over one-quarter said they had taken time off work for spinal pain in the past five years. Nearly half of respondents under 25 years of age had some degree of spinal pain. Although a very small group, ambulance workers appear to have the greatest problems. Staff involved in lifting equipment and manual work had a lower prevalence of spinal pain than nurses or ambulance workers, but were more likely to have severe pain for which analgesics were taken. Nurses had a prevalence rate of 60 per cent, but less than one third had frequent or severe pain. Based upon this information an application has been made to implement a programme to reduce both the number of injuries and the severity of those that occur.

Adult↗
PubMed1992

Is stage I epithelial ovarian cancer overtreated both surgically and systemically? Results of a five-year cancer registry review.

OBJECTIVE: To review the incidence of Stage I epithelial ovarian carcinoma in the West Midlands region and to identify prognostic factors that have a significant effect on survival. DESIGN: A retrospective review of all Stage I ovarian cancer patients registered from 1.1.80 to 31.12.84. SETTING: West Midlands Regional Cancer Registry. POPULATION: 457 patients with Stage I ovarian cancer--373 with epithelial ovarian carcinoma. MAIN OUTCOME MEASURES: Survival at censor date of 30.6.89. RESULTS: 28% developed recurrent disease, and the overall 5-year survival of the group was 70%. Univariate analysis of all possible prognostic factors showed that stage, adjuvant chemotherapy, histological grade and type, surgical rupture of the tumour, intact capsule histologically, clinical finding of ascites and the performance of peritoneal washings were significantly associated with survival. Adequate surgical staging as defined by FIGO was not significantly associated with survival. A multivariate analysis based on the Cox proportional hazard model identified histological grade, adjuvant chemotherapy, patient age and peritoneal washings as having independent prognostic effects. Surprisingly adjuvant chemotherapy and peritoneal washings had negative effects on survival. CONCLUSIONS: Although a retrospective review has limitations, it would appear that adequate surgical staging and adjuvant chemotherapy confer no benefit in terms of survival in Stage I disease.

Adolescent↗
PubMed1992

Treatment of Class II open bite in the mixed dentition with a removable functional appliance and headgear.

Early diagnosis of patients exhibiting open bites that are complicated by skeletal Class II and vertical growth problems can facilitate subsequent treatment. Eight patients with Class II skeletal open bite were treated with the high-pull activator appliance and compared to reasonably matched controls to determine the effects of the appliance. The high-pull activator was found to reduce forward growth of the maxilla and increase mandibular alveolar height, transforming the Class II molar relationship into a Class I molar relationship. The overjet and open bite were decreased, and, in addition, the appliance reduced the amount of forward and downward movement of the maxillary molars, providing vertical control of the maxilla during Class II orthopedic correction. These results demonstrated that open bite complicated by a Class II vertical growth pattern can be treated during the mixed dentition with favorable results by a combination of a removable functional appliance and high-pull headgear.

Activator Appliances↗
PubMed1991

Pharmacology of saccadic eye movements in man. 1. Effects of the benzodiazepine receptor ligands midazolam and flumazenil.

A paradigm for assessing benzodiazepine receptor sensitivity was developed using intravenous midazolam in normal volunteers. After administration of incremental doses of midazolam, alterations in saccadic eye movement parameters and psychological self ratings were assessed. Significant changes included dose-dependent slowing of peak velocity, peak acceleration, peak deceleration, reduced saccade acceleration/deceleration ratio and saccade accuracy, and increased sedation self-ratings. Changes in saccade variables and sedation ratings were significantly correlated, and also correlated with plasma midazolam concentrations. No significant changes were seen in saccade latency or anxiety self-ratings. Pharmacological specificity of these changes was demonstrated by their reversal with the benzodiazepine antagonist flumazenil. This challenge paradigm appears to be a sensitive means of assessing benzodiazepine receptor function in man.

Adult↗
PubMed1991

Pharmacology of saccadic eye movements in man. 2. Effects of the alpha 2-adrenoceptor ligands idazoxan and clonidine.

The effects of alpha 2-adrenoceptor agonists and antagonists on saccadic eye movements were studied in normal volunteers using the agonist clonidine and the antagonist idazoxan. Changes in blood pressure, heart rate, and several psychological self-ratings were also recorded. Clonidine produced marked slowing of peak saccade velocity, acceleration and deceleration, with deceleration affected more than acceleration, but had no effect on saccade error or latency measurements. In contrast, most saccade parameters were not altered by idazoxan, although fatigue effects were eliminated. Blood pressure, heart rate, and self ratings of alertness were increased by idazoxan and reduced by clonidine, with opposite effects noted on sedation self-ratings. There were no correlations between the clonidine-induced changes in saccade parameters and changes in self-ratings. Although the slowing of some saccade parameters by clonidine may imply that alpha 2-adrenoceptors are involved in control of saccades, it may also be due to sedation. Although alpha 2-adrenoceptor antagonists may abolish fatigue effects, they cannot increase them over baseline values.

Adrenergic alpha-Antagonists↗
PubMed1991

Effects of vitamin or mineral deficiency on the morphology of medullary bone in laying hens.

Adult laying hens were fed diets deficient in phosphorus, calcium, calcium and phosphorus, and vitamin D3 to determine their effects on bone histology and parathyroid gland size. The phosphorus deficient diet caused an insignificant decrease in parathyroid size while the other diets caused significant increases. A considerable amount of individual variation in medullary bone volume and osteoid seam width was observed in all groups but, despite this, the calcium, calcium and phosphorus and vitamin D3 deficient diets clearly resulted in increased osteoid. Birds receiving diets deficient in calcium and phosphorus, and in vitamin D3 for longer periods were observed to have partially or completely resorbed medullary bone. Osteodystrophia fibrosa was noted in vitamin D3 deficient birds which had no follicular activity.

Animals↗