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Biomedical subjects

M Walker

Publications and source records attributed to M Walker.

At least 631 records · Page 35Linked to original sources
PubMedDate not supplied

Correlation of clinical, radiographic, and surgical localization of intervertebral disc extrusion in small-breed dogs: a prospective study of 50 cases.

OBJECTIVE: To compare prospectively clinical, radiographic, and surgical findings of intervertebral disc extrusion (IDE) localization in small-breed dogs and to determine the best means of lesion localization for the purpose of hemilaminectomy. STUDY DESIGN: Clinical, radiographic, and surgical findings of small-breed dogs with thoracolumbar IDE were prospectively compared for agreement on lesion localization. SAMPLE POPULATION: 50 small-breed dogs with IDE treated at the three participating veterinary hospitals were included in the study if no other confounding diseases were identified and if the owner gave permission for diagnostic tests and surgery. METHODS: Clinical and surgical findings were recorded by the surgeon assigned to the case. Radiographic studies were evaluated independently by two radiologists blinded as to the clinical and surgical findings. kappa values and 95% confidence intervals were calculated for agreement on lesion localization by clinical, radiographic, and surgical means and for agreement between radiologists. RESULTS: kappa values for agreement of lesion localization were as follows: clinical versus surgical, 0.595; radiologist A versus radiologist B, 0.81; radiologist A versus surgical findings, 0.60; radiologist B versus surgical findings, 0.71. Both radiologists' interpretation of IDE localization agreed with surgical localization in 60% of cases. CONCLUSIONS: Clinical lateralization of IDE was found to be the least reliable factor of those studied for determining on which side the hemilaminectomy should be performed. Results of this study differ from those of previous studies examining the reliability of myelography to localize the site of IDE accurately. The results of this study further suggest that surgery may not be an absolute standard for determination of the localization of IDE in small-breed dogs. CLINICAL RELEVANCE: Intervertebral disc extrusion in small-breed dogs frequently results in bilateral distribution of extruded material. Computed tomography or magnetic resonance imaging may be necessary to delineate completely the distribution of extruded disc material in IDE.

Animals↗
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Neonatal nutrition.

Explore the source record for details and available documents.

Humans↗
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Principles of a therapeutic milieu: an overview.

The author provides a concise overview of how the milieu functions of structure, involvement, containment, support, and validation can be used to create a positive treatment environment. Examples of an unhealthy milieu are contrasted with these therapeutic principles.

Humans↗
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Radiotherapy of metastatic seminoma in the dog. Case reports.

Four dogs with metastatic seminoma were treated with cesium 137 teleradiotherapy. Minimum total tumor dose ranged from 17 to 40 gray (Gy) and was usually given through bilateral opposing sublumbar ports in eight to ten fractions, with three fractions given weekly. The tumor regressed in all four dogs. The first dog (case 1) was free of tumor and died of non-tumor related causes at 57 months. The second dog (case 2) was free of tumor but was euthanatized at 37 months for a limb fracture. The third dog (case 3) was euthanatized for undertermined pulmonary disease 43 months after radiotherapy. The fourth dog (case 4) was euthanatized 6 months following radiotherapy because of transitional cell carcinoma and renal failure. No evidence of seminoma was found at necropsy. Radiotherapy was shown to be effective treatment for seminoma with regional metastasis.

Animals↗
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First trimester fetal heart rate: response to chorionic villus sampling in the chromosomally normal fetus.

The objective of this prospective study was to evaluate the fetal heart rate before and after the procedure and whether this had any effect on the risk of pregnancy loss following chorionic villus sampling (CVS) and chromosomally normal pregnancies. Four hundred and seventeen pregnancies were evaluated. The heart rate before the procedure was similar for both male and female fetuses. Significant procedure-related changes in fetal heart rate occurred only with male fetuses undergoing the transabdominal CVS technique. Fetal heart rate decelerations following CVS were more common than accelerations. Fetal heart rate changes following CVS were not able to predict the pregnancies ending in spontaneous abortion. Transabdominal CVS had a lower loss rate after the procedure, compared to the transcervical technique (p = 0.0001). Small-for-date fetuses had a higher loss rate after the procedure compared to normal-sized fetuses (p = 0.001).

Abortion, Spontaneous↗
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A new combination therapy for selective and prolonged antiplatelet effect: results in the dog.

This study characterizes the effect of dazmegrel, a thromboxane synthetase inhibitor, on platelet function in the dog and introduces its potential use in combination with aspirin therapy. Ex vivo testing of dazmegrel alone was performed with three dosages and three administration regimens. Platelet aggregation response, malondialdehyde formation and prostaglandin metabolites generation were evaluated. To maintain complete thromboxane A2 inhibition, dazmegrel had to be given 3 times per day at dosages of not less than 6 mg/kg. The same result was achieved with a single daily administration of combined dazmegrel and aspirin in equal dosages of 3 mg/kg. Dazmegrel, both alone and with aspirin, increased and sustained heightened levels of prostacyclin, unlike the simultaneous inhibition of both prostaglandin metabolites seen with aspirin therapy alone. Because the combination of dazmegrel and aspirin effectively blocks thromboxane A2 formation and also enhances prostacyclin formation, the synergistic action of these agents increases their combined antiplatelet effect to a level not attainable by either agent alone. The significance of this combined therapy warrants further experimental study and may soon merit clinical trial for the prevention of stroke and other major thrombotic complications.

6-Ketoprostaglandin F1 alpha↗
PubMedDate not supplied

Reverberations from the Sounding Board ... Waiting Your Turn.

In the July/August 1993 Sounding Board, Leadership presented four commentaries on Waiting Your Turn: Hospital Waiting Lists in Canada (third edition), prepared by the Fraser Institute's Joanna Miyake and Michael Walker. Waiting Your Turn, released in May 1993, surveyed 2,147 physicians in late 1992 and, based on the results, compares access to common surgical procedures in all 10 provinces. Commenting on the report for Leadership were Charles W. McDougall, executive vice-president and COO of Montreal's Royal Victoria Hospital; Liza Kallstrom, manager of the health policy department at the British Columbia Health Association; Carol Gabanna, executive director of the Hospital Association of Prince Edward Island; and Dr. Hugh E. Scully of The Toronto Hospital. In this issue, Michael Walker responds.

Canada↗
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Measuring the prevalence of disease in middle-aged British men.

OBJECTIVE: To identify and validate a measure of disease prevalence in a town or other subpopulation for the purpose of estimating variations in morbidity and health care needs between groups. DESIGN: A national prospective study of cardiovascular disease based in 24 British towns. SUBJECTS: 7,735 men aged 40-59 years sampled from 24 general practice age-sex registers between 1978 and 1980. METHOD: A questionnaire administered at recruitment and a postal questionnaire five years later (98% response) asked if the subject recalled ever having had a diagnosis by a doctor of any of 12 listed conditions. In addition, the men were asked about regular medication, occupation, lifestyle and perceived health status. All-cause mortality data were collected during 13.5 years of follow-up. RESULTS: Prevalence of recalled doctor diagnoses varied between the towns; for cardiovascular disease, it correlated significantly with other health indices and personal characteristics and with standardised mortality ratios for the town. Consistency of reporting over time and mortality outcome after 13.5 years also supported the validity of patient recall. CONCLUSIONS: A simple standardised questionnaire using patient recall of common conditions diagnosed by a doctor provides a plausible, valid measure of variations in disease burden between communities.

Adult↗
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Goodpasture's syndrome: a nursing challenge.

Goodpasture's syndrome is an uncommon occurring disorder that causes hemorrhage in the basement membrane lining of the kidneys and the lungs. By recognizing early signs and symptoms of pulmonary-renal syndromes that may lead to a diagnosis of Goodpasture's syndrome, critical care and advanced practice nurses can play a key role in ensuring successful patient outcomes and preventing complications. Expert nursing care and emotional support is essential for the patient and family to cope with this usually fatal disease.

Anti-Glomerular Basement Membrane Disease↗
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Dual-purpose, radiographic-surgical implant template: fabrication technique.

A technique for fabrication of an implant radiographic-surgical template for the partially-edentulous patient is proposed. A mixture of barium sulfate and acrylic resin provides a radiopaque template of the planned implant restorations in relation to the hard tissues. This template is easily converted to a surgical guide.

Dental Implantation, Endosseous↗
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Suppression of androgen action and the induction of gross abnormalities of the reproductive tract in male rats treated neonatally with diethylstilbestrol.

This study evaluated whether androgen action is altered in rats treated neonatally with diethylstilbestrol (DES) at a dose that induced reproductive tract abnormalities. Rats were treated on alternate days 2-12 with 10 microg DES and studied on Day 18. DES-induced abnormalities included a 70% reduction in testis weight, distension and overgrowth of the rete, distension and reduction in epithelial height of the efferent ducts, underdevelopment of the epididymal duct epithelium, reduction in epithelial height in the vas deferens, and convolution of the extra-epididymal vas. In DES-treated rats, androgen receptor (AR) immunoexpression was virtually absent from all affected tissues and the testis, whereas AR expression in controls was intense in epithelial and stromal cells. The DES-induced change in AR immunoexpression was confirmed by Western analysis for the testis. In rats treated neonatally with 1 microg DES, reproductive abnormalities were absent or minor, except for a 38% reduction in testis weight; loss of AR immunoexpression also did not occur in these rats. Treatment-induced changes in AR expression were paralleled by changes in Leydig cell volume per testis (91% reduction in the 10-microg DES group; no change in the 1-microg DES group). To test whether suppression of androgen production or action alone could induce comparable reproductive abnormalities to 10 microg DES, rats were treated neonatally with either a potent gonadotropin-releasing hormone antagonist (GnRHa) or with flutamide (50 mg/kg/day). These treatments reduced testis weight (68% for GnRHa, 40% for flutamide), and generally retarded development of the reproductive tract but failed to induce the abnormalities induced by 10 microg DES. GnRHa and flutamide caused no detectable change in AR immunoexpression in target tissues, with the exception of minor changes in the testes of flutamide-treated males. GnRHa treatment caused a reduction (83%) in Leydig cell volume comparable to that caused by 10 microg DES. Immunoexpression of estrogen receptor alpha (ER alpha) in the efferent ducts and of ER beta in all tissues studied were unaffected by any of the above treatments. Neonatal coadministration of testosterone esters (TE; 200 microg) with 10 microg DES prevented most of the morphological abnormalities induced by 10 microg DES treatment alone, though testis weight was still subnormal (46% reduction in DES + TE vs 72% in DES alone and 49% with TE alone) and some lumenal distension was still evident in the efferent ducts. Coadministration of TE with DES prevented DES-induced loss of AR immunoexpression (confirmed for testis by Western blot analysis). It is concluded that 1) reproductive tract abnormalities induced in the neonatal male rat by a high (10 microg) dose of DES are associated with reduced AR expression and Leydig cell volume; 2) these changes are largely absent with a lower dose of DES (1 microg); 3) treatments that interfere with androgen production (GnRHa) or action (flutamide) alone failed to induce reproductive tract abnormalities or alter AR expression as did 10 microg DES; 4) a grossly altered androgen:estrogen balance (low androgen + high estrogen) may underlie the reproductive tract abnormalities, other than reduced testis weight, induced by high doses of DES.

Androgen Antagonists↗
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Food intake of women with breast cancer during their first six month of chemotherapy.

Significant alterations in the nutritional patterns of the patient with cancer can inhibit the patient's ability to combat the disease and withstand the impact of cancer treatments. This study compared the food intake patterns of women with breast cancer receiving adjuvant chemotherapy with those of healthy women to determine if significant alterations in food intake occurred during the first six months of treatment. Results indicated that, although alterations in taste did occur, food aversions did not develop. Throughout the study, women with breast cancer were eating a significantly greater number of calories and food servings than women who did not have breast cancer. The women with breast cancer were likely to report taste changes for foods such as beef, pork, chicken, coffee, and cakes. However, these taste changes could not account for alterations in dietary intake.

Adult↗