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Biomedical subjects

K Evans

Publications and source records attributed to K Evans.

At least 109 records · Page 6Linked to original sources
PubMed1994

Loss of regional bone mineral density in the first 12 months following renal transplantation.

A high incidence of osteopenia is likely in renal transplant recipients in whom pre-existing uraemic osteodystrophy, persisting hyperparathyroidism and glucocorticoids constitute a formidable array of risk factors. The correction of some biochemical and hormonal abnormalities, an increase in body weight and an increase in physical activity following transplantation could favour improvements in skeletal integrity. Using dual energy X-ray absorptiometry (DEXA), we studied prospectively the regional bone mineral density (BMD) of 34 consecutive cadaveric renal allograft recipients who were already established on dialysis. BMD of these patients was measured at the time of transplantation and was repeated at 3, 6 and 12 months following the transplantation. Immunosuppression was achieved using triple therapy: azathioprine, cyclosporin-A and prednisolone. At baseline, total BMD and BMD at the lumbar spine and femoral neck did not differ from age- and sex-matched controls. Females experienced marked and progressive bone loss at the lumbar spine, with less marked changes at the femoral neck. Males, in contrast, experienced substantial reduction of BMD at the femoral neck at 6 months and a recovery at 12 months without significant change at the lumbar spine. Whole body bone mineral content fell transiently in males, with partial recovery by 6 months. No significant correlation was found with the cumulative doses of either corticosteroids or cyclosporin-A, the duration of hospitalisation, the function of the transplant, patient age or menopausal status.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1993

Copper-64 metabolism in two patients with non-Wilsonian movement disorders and copper deficiency.

Copper-64 studies are presented of 2 patients with non-Wilsonian movement disorder and with abnormal copper handling. Both patients differed from the usual phenotype of non-Wilsonian low copper movement disorder as they had choreiform movement disorders with an onset in the first decade; one patient lacked significant intellectual impairment. Both patients had reduced serum total copper and marginal free copper and caeruloplasmin levels, and both patients were capable of incorporating 64Cu2+ into caeruloplasmin but the second case did so at markedly reduced level. Both showed slightly increased basal and stimulated urinary copper loss compared to normal controls with the rate in patient 1 being capable of leading to copper depletion. Liver copper content was normal in both cases. These 2 patients add to the reports of cases with copper deficiency and movement disorder in whom copper chelation therapy is unlikely to be beneficial.

Adult↗
PubMed1993

Does long-term administration of tamoxifen affect bone mineral density?

A retrospective study was performed to determine whether the long-term (5 years or more) administration of tamoxifen is detrimental to bone mineral density (BMD). 19 patients taking adjuvant tamoxifen for breast cancer were paired with 19 controls comparable in age, time since menopause and performance status. BMD was measured at the femoral neck, lumbar spine and total body by dual energy X-ray absorptiometry (DEXA). There was no detrimental effect on BMD at any site. There was a trend towards an increase in BMD at the femoral neck. There were minor decreases in the serum calcium, phosphate and alkaline phosphatase.

Absorptiometry, Photon↗
PubMed1993

Neovascular complications after central retinal vein occlusion.

An 8-year retrospective study of patients suffering a central retinal vein occlusion (CRVO) was undertaken to study secondary new vessel formation and whether pathologies known to predispose to CRVO influenced the occurrence of these neovascular complications and their responsiveness to treatment. Seventy-three patients were studied. Ocular neovascularisation had occurred in 60%. More specifically 39% developed neovascular glaucoma. Panretinal photocoagulation produced regression in only 37% of those with established neovascularisation and was unsuccessful in preventing neovascularisation in five patients treated prophylactically. Patients with pre-existing primary open angle glaucoma (POAG) were statistically more likely to develop ocular neovascularisation (p = 0.02), which was also less responsive to laser therapy (p = 0.02). Adequate prior glaucoma therapy did not protect against this enhanced complication rate. It was concluded that POAG is a significant risk factor for developing ocular neovascularisation after CRVO which will be refractory to laser therapy.

Adult↗
PubMed1993

Reduced bone mineral density in long-term survivors of medulloblastoma.

Bone mineral density (BMD) reaches a peak at approximately 30 years of age, and may be influenced by radiotherapy before completion of skeletal maturation. Regional BMD has been measured using dual energy X-Ray absorptiometry (DEXA) in adults following craniospinal irradiation for medulloblastoma between ages 4 and 19 years, receiving doses of 3500-4000 cGy to the brain and spinal cord. Lumbar spine (LS) and was failure to achieve normal adult BMD at both LS and FN, with a mean reduction at LS of 12.1% +/- 2.4% (p < 0.01) and a mean reduction at FN of 14.3% +/- 3.4% (p < 0.01). The mean body mass index (BMI) was also less than that of a standard population (21.8 +/- 1.5), as were mean standing and sitting heights. No relationship was found between reduction in BMD at either site and age at irradiation, time elapsed since irradiation or BMI at time of scanning. Biochemical and endocrine markers including corrected calcium, alkaline phosphatase, sex hormones and IGF-1 were normal in all seven patients. The reduction in BMD outside the irradiated area suggests that indirect factors may be important in this effect.

Adolescent↗
PubMed1993

Schizophrenia-associated chromosome 11q21 translocation: identification of flanking markers and development of chromosome 11q fragment hybrids as cloning and mapping resources.

Genetic linkage, molecular analysis, and in situ hybridization have identified TYR and D11S388 as markers flanking the chromosome 11 breakpoint in a large pedigree where a balanced translocation, t(1;11)(q43;q21), segregates with schizophrenia and related affective disorders. Somatic cell hybrids, separating the two translocation chromosomes from each other and from the normal homologues, have been produced with the aid of immunomagnetic sorting for chromosome 1- and chromosome 11-encoded cell-surface antigens. The genes for two of these antigens map on either side of the 11q breakpoint. Immunomagnetic bead sorting was also used to isolate two stable X-irradiation hybrids for each cell-surface antigen. Each hybrid carries only chromosome 11 fragments. Translocation and X-irradiation hybrids were analyzed, mainly by PCR, for the presence of 19 chromosome 11 and 4 chromosome 1 markers. Ten newly designed primers are reported. The X-irradiation hybrids were also studied cytogenetically, for human DNA content, by in situ Cot1 DNA hybridization and by painting the Alu-PCR products from these four lines back onto normal human metaphases. The generation of the translocation hybrids and of the chromosome 11q fragment hybrids is a necessary preliminary to determining whether a schizophrenia-predisposition gene SCZD2 is encoded at this site.

Animals↗
PubMed1992

Factors affecting cervical anastomotic leak and stricture formation following esophagogastrectomy and gastric tube interposition.

Following esophagectomy, restoration of swallowing by gastric tube interposition with cervical esophagogastric anastomosis reduces morbidity and mortality associated with intrathoracic anastomoses at the expense of an increased incidence of both anastomotic leak and stricture formation. A retrospective study of 165 patients with either squamous cell carcinoma or adenocarcinoma of the distal esophagus or gastric cardia undergoing esophagogastrectomy with gastric tube interposition and cervical anastomosis at Vancouver, British Columbia, or London, Ontario, was undertaken. Forced-entry multiple logistic regression analysis of factors believed to influence anastomotic outcome was performed. Anastomotic leak occurred in 17% of patients; statistically significant correlation with low preoperative serum albumin (p = 0.005), running suture technique (p = 0.029), high intraoperative blood loss (p = 0.038), and the occurrence of postoperative delayed gastric emptying (p = 0.045) was found. Anastomotic strictures occurred in 31% of patients; a statistically significant correlation was found with preceding anastomotic leak (p = 0.001) and intraoperative blood loss (p = 0.042). Factors including preoperative radiotherapy and diabetes mellitus were not found to be significant.

Anastomosis, Surgical↗
PubMed1992

Manipulation of the fractured nose under local anaesthesia.

Simple fractures of the nasal pyramid without significant septal deformity may be reduced as effectively under local as under general anaesthesia. Currently, the former may involve regional nerve blockade by intranasal infiltration and is often unpleasant. We have attempted to find a more acceptable method. Fifty consecutive, adult patients with clinically displaced nasal fractures were randomized to receive either blocks of the infraorbital, infratrochlear and external nasal nerves by intranasal infiltration or generalized infiltration of the nasal dorsum by an external route. All patients received intranasal cocaine. Following manipulation, each patient recorded their overall discomfort level and subjective nasal airway patency. The surgeon recorded the cosmetic result. Analysis revealed the internal route to be significantly more painful (P less than 0.001) and with no advantage to the patient with respect to post-operative airway patency or cosmesis. We recommend the technically easier external method for this procedure.

Adult↗
PubMed1992

Effect of synchronous and asynchronous pulsatile flow during left, right, and biventricular bypass.

Ventricular assist devices augment flow from the left atrium to the aorta and/or from the right atrium to the pulmonary artery. Most devices are used in the asynchronous full-to-empty mode (asynchronous) but may also be used in a synchronous counterpulsation mode (synchronous). This study determines the optimal assist modes to reduce myocardial oxygen consumption (MVO2) and metabolism. Twelve pigs were instrumented with carotid artery and Baim coronary sinus catheters for determination of MVO2 and myocardial lactate production (LACT). Six were implanted with a Pierce-Donachy left ventricular assist device (LVAD) and 6 with both right and left ventricular assist devices (BIVAD). Two periods each of control, synchronous, and asynchronous bypass were instituted, the midanterior descending coronary artery (LAD) was ligated, and the sequence was repeated. After each period, MVO2 and LACT were determined and myocardial biopsy specimens were obtained for tissue, lactate, and ATP assay. Following LAD ligation, biopsy specimens were obtained from both the infarct and noninfarct zones of the heart. MVO2 decreased (p < 0.05) in the asynchronous BIVAD mode compared with control. MVO2 was unchanged in synchronous BIVAD or either LVAD mode. Tissue ATP and tissue lactate were unaffected by any mode of bypass. Only BIVAD in the asynchronous mode reduced MVO2. When ventricular assist devices are utilized to aid recovery of the natural heart, two devices should always be inserted to allow biventricular assist. Synchronous counterpulsation offers no advantage.

Adenosine Triphosphate↗
PubMed1992

Intraocular pressure measurement in children using the Keeler Pulsair tonometer.

A study to determine whether Keeler Pulsair tonometry is a feasible alternative to tonometry under general anaesthesia in children was undertaken. We recruited 53 children aged from 6 months to 9 years old. Readings were obtainable from 78% and a complete set of four readings from each eye was obtained from 45% of the group in an out-patient setting. Averaged Pulsair measurements agreed well with Perkins applanation tonometry values under general anaesthesia. Techniques to improve compliance are discussed. In conclusion, the Pulsair tonometer is a viable method for obtaining estimates of intraocular pressure in children in this age-group.

Anesthesia, General↗
PubMed1992

Changes in total body bone mineral content and regional bone mineral density in renal patients following renal transplantation.

We performed serial measurements of total body bone mineral content (BMC) and bone mineral density (BMD), and of regional BMD at the lumbar spine and femoral neck using dual energy X-ray absorptiometry. Twenty-six patients (15 females and 11 males) were studied at the time of transplantation, and 3 and 6 months post-transplant. At baseline, the total body BMC and regional BMD values of the patients did not differ significantly from age- and sex-matched controls. Total body BMC had fallen progressively at 3 months, followed by partial recovery at 6 months. Significant decreases of BMD were seen in the lumbar spine and femoral neck at 3 months with no evidence of recovery at 6 months. The changes in these indices correlated well with the duration of hospital stay in the first 3 post-transplant months. This preliminary study demonstrated rapid deterioration of skeletal integrity following renal transplantation and that this might be progressive. Preventative strategies to avoid this early bone loss may need to be investigated.

Absorptiometry, Photon↗
PubMed1991

Hemoperitoneum secondary to traumatic rupture of an adrenal tumor in a dog.

Hemoperitoneum secondary to traumatic rupture of an adrenocortical adenocarcinoma was diagnosed in a 10-year-old male dog. Immediate surgical attention was required to remove the tumor and to control hemorrhage. The dog appeared to develop transient hypoadrenocorticism after surgery, but recovered with short-term exogenous corticosteroid administration. At 6 months after surgery, the dog was clinically normal.

Adenocarcinoma↗
PubMed1991

Cleft anterior segment with maternal hypervitaminosis A.

We report a case of an 'hourglass' cornea and iris with reduplicated lens in the left eye of an infant girl. An excess of vitamin A products had been taken by the mother during pregnancy. Mechanisms by which vitamin A excess could have caused this are discussed.

Abnormalities, Drug-Induced↗
PubMed1991

Achievement of objectives: internal medicine fourth year clinical clerkship.

The clinical clerkship in Canadian Medical Schools is intended to provide senior medical students with opportunities to gain practical knowledge of clinical medicine, develop technical skills, learn to use judgement and experience first-hand clinical decision making. Assessment of rotations in internal medicine were undertaken in order to understand more fully the nature of medical clerkship experiences. We found that medical clerks in our programme were exposed to a high proportion of undifferentiated problems and an adequate case mix. They performed a wide range of technical procedures. There were, however, certain gaps in the clerks' experiences both in the specialty areas, and in therapeutic and technical procedures. Recognition of these gaps in the clerkship experiences suggest that further deliberation of goals and objectives is required and issues of achievement of competencies need to be addressed.

Adult↗
PubMed1991

Standard setting: an introduction to differing approaches.

In recent years there have been widespread developments in the National Health Service concerning quality assurance programmes. Differing approaches have been established throughout the United Kingdom and to individuals new to the field it is easy to become confused with the wide range of approaches described in many nursing and health service journals. A common theme in all such programmes involves defining the standard of service to be provided, then attempting to measure that service. This article will examine four different approaches to standard setting based on a multidisciplinary discharge standard. The process of setting the standards will be described and critiqued in each case, and this will be followed in the final section by a discussion of the different approaches.

Humans↗