Search PubMed⌕ Search

Biomedical subjects

K Cox

Publications and source records attributed to K Cox.

At least 19 recordsLinked to original sources
PubMed1992

Sequence similarity between macrolide-resistance determinants and ATP-binding transport proteins.

The three macrolide-resistance-encoding genes, tlrC from Streptomyces fradiae, srmB from Streptomyces ambofaciens, and carA from Streptomyces thermotolerans, encode proteins that possess significant sequence similarity to ATP-dependent transport proteins. The N-terminal and C-terminal halves of these proteins are very similar to each other and contain highly conserved regions that resemble ATP-binding domains typically present within the superfamily of ATP-dependent transport proteins. These observations suggest that the mechanism by which these genes confer resistance to macrolides is due to export of the antibiotics, a process that is driven by energy derived from ATP hydrolysis.

Adenosine Triphosphate↗
PubMed1992

Suppression of experimental autoimmune encephalomyelitis by gallium nitrate.

We examined the effect of gallium (Ga) nitrate on the development of the development of experimental autoimmune encephalomyelitis (EAE). Weekly subcutaneous injections of 10-30 mg/kg prevented clinical signs as well as histopathological changes of EAE. The optimal timing of a single injection of Ga was 6 days after induction of EAE, with amelioration also apparent following a single injection on day 3 or 9 but not day 12. Ga administered in vivo suppressed myelin basic protein (MBP) and purified protein derivative-specific lymphocyte proliferative responses in vitro. Addition of Ga to MBP-specific T lymphocyte line cultures at various times after initiation of culture revealed that Ga exerts an effect at an early stage of cellular activation.

Animals↗
PubMed1992

Severe vascular adverse effects with thrombocytopenia and renal failure following emetogenic chemotherapy and ondansetron.

During late 1991, a series of severe adverse events involving thrombocytopenia, renal insufficiency and thrombotic episodes was observed in patients receiving emetogenic chemotherapy. Two patients died, one of renal failure and one of cerebral haemorrhage in the presence of thrombocytopenia. Other severe side effects included thrombosis of the aorta causing paraplegia and multifocal cerebral infarctions. Common exposure features included the use of ondansetron and dexamethasone as antiemetics, and in most of the cases high dose (100 mg/M2 or more) cisplatin. Retrospective review of a series of patients treated with similar cytotoxic regimens for similar diseases before the use of ondansetron revealed no similar adverse effects, but no substantial differences were observed in renal function or haematologic toxicity in the two groups overall. Sporadic adverse vascular events have been observed before the use of ondansetron. The mechanism remains unknown, and it is not clear whether ondansetron was a factor in the unusual incidence of such events in the present series.

Adult↗
PubMed1992

Effects of policy manual reorganization on user proficiency.

This study compared the proficiency of nurses who located policies in a traditional, alphabetically arranged policy manual vs. a reorganized, indexed manual. Nurses were asked to locate policy statements that would resolve issues presented in three vignettes that were typical of the decisions nurses must regularly make. Answers were scored as correct or incorrect; time to respond and search strategies were also recorded. Data analyses show the overall superiority of the reorganized, indexed manual.

Abstracting and Indexing↗
PubMed1992

Phase II clinical trial of recombinant alpha-2 interferon for biopsy-proven metastatic or recurrent renal carcinoma.

Twenty patients with histologically confirmed metastatic or recurrent renal carcinoma were treated in a phase II study with alpha-interferon (2-5 x 10(6) U/m2 subcutaneously, 3 times a week). Nineteen patients had multiple sites of disease and 18 had previously undergone nephrectomy; 9 had an ECOG performance status of 0.1, and 11 had a performance status of 2-3. There was one partial response, yielding an overall response rate of 5%. Treatment was well tolerated, although 7 patients developed influenza-like symptoms, and in 2 cases this was sufficiently severe for the patients to request cessation of treatment. As a single agent at this dose schedule, alpha-interferon has minimal activity in the treatment of renal carcinoma and cannot be recommended as standard therapy. The difference in outcome between this and some published series may reflect the stringent requirement for histological proof of the presence of metastases.

Adult↗
PubMed1992

Hypercholesterolemia after chemotherapy for testis cancer.

PURPOSE: The study was designed to determine prospectively the prevalence of fasting serum lipid abnormalities in patients who were treated with cisplatin-based chemotherapy for germ cell tumors. We unexpectedly had demonstrated hypercholesterolemia in 20 of 30 nonfasting patients in a prior study of long-term toxicity of chemotherapy for germ cell tumors. The present study was designed to explore this phenomenon further. PATIENTS AND METHODS: Seventeen unselected patients with biopsy-proven germ cell tumors, who underwent cisplatin-based chemotherapy and who had no prior history of cardiac disease nor known hypercholesterolemia, were studied. In addition to the standard staging tests, blood was drawn for a pretreatment fasting lipid screen, which included cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, and apolipoproteins A1, B, and (a). Repeat samples were drawn 24 hours after the administration of cisplatin and at intervals of 6 to 24 months after the completion of treatment. RESULTS: Seven of 17 patients (41%) had higher than desirable levels of total serum cholesterol and low-density lipoprotein cholesterol. Two of them had normal levels before treatment, four had preexisting hypercholesterolemia that increased further, and one patient had an elevated pretreatment level that did not alter. Absolute increases in serum cholesterol were noted in 14 of 17 patients. No consistent patterns of change beyond the reference ranges were found for other serum lipids. CONCLUSIONS: We have confirmed our initial observation that serum cholesterol increases in patients who received cisplatin-containing chemotherapy regimens for germ cell tumors. Further studies will be necessary to define whether other lipid abnormalities occur and the biologic significance of these findings.

Adolescent↗
PubMed1991

The impact of liver reductions in pediatric liver transplantation.

Reduced-size liver transplantation (RSLT) in children was introduced to alleviate a shortage of small-organ donors. The impact of RSLT on the waiting time for an organ and on morbidity and mortality was investigated. Between March 25, 1988, and August 11, 1990, 61 hepatic transplantations were performed in 55 children at the Pacific Transplant Institute in San Francisco, Calif. Full-size liver transplantation was performed in 41 cases and RSLT in 20 cases. The overall 30-month actuarial patient and graft survival rates were 89% and 73%, respectively. A comparison between full-size liver transplantation and RSLT showed no difference in patient and graft survival, reoperations, infections, or rejection. Benefits of RSLT were an increase in the donor pool size, a decrease in waiting time for a suitable donor, and a decrease in the rate of arterial thrombosis. The main morbidity of RSLT was an increase in perioperative blood requirement. We conclude that RSLT offers small children with end-stage liver disease a chance for long-term survival.

Actuarial Analysis↗
PubMed1991

Parvalbumin-immunoreactive neurons in the neocortex are resistant to degeneration in Alzheimer's disease.

Recent studies have stressed the fact that specific neuronal subtypes may display a differential sensitivity to degeneration in Alzheimer's disease. For example, large pyramidal neurons have been shown to be vulnerable, whereas smaller neurons are resistant to pathology. Using a monoclonal antibody against the calcium-binding protein parvalbumin, we investigated the possible changes in a subpopulation of interneurons in two cortical areas known to be strongly damaged in Alzheimer's disease. In the prefrontal cortex as well as in the inferior temporal cortex, we observed no differences in parvalbumin-immunoreactive cell counts or cell size in Alzheimer's disease brains as compared to control cases. Moreover, the general cellular morphology of these neurons was preserved in the Alzheimer's disease cases, in that their perikarya and dendritic arborizations were intact. These results suggest that paravalbumin-immunoreactive cells represent a neuronal subset resistant to degeneration, and further support the hypothesis that the pathological process in Alzheimer's disease involves specific neuronal subtypes with particular morphological and molecular characteristics.

Aged↗
PubMed1991

Unilateral external fixation until healing with the dynamic axial fixator for severe open tibial fractures.

One hundred one cases of open tibia fractures were treated until healing with a unilateral external fixation device that permits fracture site compression with weight bearing. There were 38 type II and 63 type III (24 IIIA, 33 IIIB, six IIIC) open fractures. A standard protocol was followed including irrigation and debridement and, when necessary, flap coverage (19 cases) and bone grafting (31 cases). Fixators were applied at the first debridement and removed when the fracture was healed. All patients were permitted early partial weight bearing and progressed to full weight bearing with fixator dynamization. Ninety-six cases healed in the fixator (12-50 weeks; average, 24.6). Three of the five failures were associated with screw complications. Five patients required screw changes and 29 required oral antibiotic therapy for screw complications. Ninety-five percent of healed cases had angulation of less than 10 degrees (in any plane). There were only six fracture site infections during the course of treatment. Dynamic axial fixation may be applied at the first debridement and be used until healing in severe open tibia fractures. Change of the fixator to another treatment method is not required.

Adolescent↗
PubMed1991

Sleep medication in Dutch hospitals.

Insomnia is an important nursing problem in hospitals. Although sleep medication is often criticized, it is one of the commonest interventions with regard to sleep problems. In this study, the prescription and provision of sleep medication in three Dutch general hospitals is investigated. Results show that on a random day 47% of all patients (n = 1076) of the surgical and medical wards were prescribed medication. Thirty-four per cent actually received sleep medication that evening or night. The prescription and provision of sleep medication was higher on medical than on surgical wards. Furthermore, hospitals were shown to differ regarding the prescription and provision of as-needed sleep medication. The study also explores whether attitudes of nurses are related to the provision of as-needed sleep medication. Although their influence does not seem to be great, it is concluded that more attention has to be paid to possible effective nursing interventions in educational programmes.

Adult↗
PubMed1991

Liver transplantation. Experience with 100 cases.

Between March 1988 and November 1989, 100 liver transplants were performed on 90 patients at Pacific Presbyterian (now California Pacific) Medical Center in San Francisco. The immunosuppressive regimen was a combination of prophylactic Minnesota antilymphocyte globulin, cyclosporine, and low-dose corticosteroids. Rejections were treated with OKT3, a monoclonal antibody, or corticosteroids. Of the 100 transplants, 32 were done on 30 children, 18 of whom weighed less than 10 kg and 9 of whom received livers that had been surgically reduced in size to fit the recipient. The overall patient survival at 2 years was 85%. Of 100 liver transplants, treatment was given for 80 (80%) for at least 1 episode of rejection. At least 1 episode of serious infection occurred in 34 of the 60 adult patients and 25 of the 30 children. Of the entire group, 2% had hepatic artery thrombosis, and 12% had biliary complications that necessitated reoperation. The quality of life has been good, with a follow-up from 1 to almost 3 years (mean = 22 months). Comparing these data with those of other published series shows a decreased incidence of surgical complications and a lower rate of fungal and viral infections. We attribute this to the reduction of steroid dosage during convalescence without jeopardizing patient or graft survival.

Adolescent↗
PubMed1991

Disciplines within general practice.

The disciplines within general practice derive partly from its community setting, and partly from the nature of professional expertise. The maladies range from a high prevalence of low risk, self-limited illness to a low prevalence of high risk, persistent disease. Each set calls on different knowledge and skills. The setting offers the substrate for studying social and behavioural sciences and community health development in action. Choosing a few particular fields, and developing those with rigour, could strengthen general practice as a discipline with special insights and skills to offer all branches of clinical practice. Four fields of activity have been identified. In each, general practice has a clear responsibility and opportunity. I have suggested some knowledge and skill areas for their success--clinical 'working' knowledge, decision making and judgment, predictive knowledge, planning knowledge, calibration of investigators, intuitive knowledge, local knowledge, leadership skills and people management, measurement of burden of illness, calculation of cost-benefit trade-offs, building of local databases, re-learning fine discrimination in clinical perception, and understanding of community development. These subjects have not been part of formal medical education, or of much academic study in family practice. Despite their being central to the success of daily practice, the curriculum is silent about the study of these areas of practical knowledge, reasoning, judgment and skill. Worse, we do not have a common language to express clearly what we are talking about. Experience and skill lie within the practitioner, and are used in practical, concrete situations.(ABSTRACT TRUNCATED AT 250 WORDS)

Family Practice↗
PubMed1990

Quantitative analysis of a vulnerable subset of pyramidal neurons in Alzheimer's disease: I. Superior frontal and inferior temporal cortex.

Various cytoskeletal proteins have been implicated in the cellular pathology of Alzheimer's disease. A monoclonal antibody (SMI32) that recognizes nonphosphorylated epitopes on the medium (168 kDa) and heavy (200 kDa) subunits of neurofilament proteins has been used to label and analyze a specific subpopulation of pyramidal neurons in the prefrontal and inferior temporal cortices of normal and Alzheimer's disease brains. In Alzheimer's disease, the distribution of neuropathological markers predominates in layers III and V in these association areas. In these neocortical regions, SMI32 primarily labels the perikarya and dendrites of large pyramidal neurons, predominantly located within layers III and V. In Alzheimer's disease, a dramatic loss of SMI32-immunoreactive (ir) cells was observed, affecting particularly the largest cells (i.e., cells with a cross-sectional perikaryal area larger than 350 microns 2). The staining intensity of the largest SMI32-ir neurons was significantly reduced in Alzheimer's disease cases, suggesting that an inappropriate phosphorylation of these cytoskeletal proteins may take place in the course of the pathological process. In addition, the SMI32-ir neuron loss and total neuron loss were highly correlated with neurofibrillary tangle counts, whereas such a correlation was not observed with neuritic plaque counts. These quantitative data suggest that SMI32-ir neurons represent a small subset of pyramidal cells that share certain anatomical and molecular characteristics and are highly vulnerable in Alzheimer's disease. Other studies have suggested that SMI32-ir neurons are likely to furnish long corticocortical projections. Thus, their loss would substantially diminish the effectiveness of the distributed processing capacity of the neocortex, resulting in a neocortical isolation syndrome as reflected by the clinical symptomatology observed in these patients. Such correlations between the expression of a selective cellular pathology and specific elements of cortical circuitry will increase our understanding of the molecular and cellular characteristics underlying a given neuronal subclass vulnerability in Alzheimer's disease or other neurodegenerative disorders.

Aged↗
PubMed1990

Selection of the T-cell repertoire in transgenic mice expressing a transplantation antigen in distinct thymus subsets.

Transgenic mice that expressed a transplantation antigen, H-2Kb, in an unusual tissue distribution have been developed. Gene-regulatory elements from the immunoglobulin heavy-chain locus (Emu enhancer and heavy chain promoter) were linked to the class I Kb gene and the construct microinjected into fertilized mouse eggs of a different haplotype. It was expected that such gene-regulatory elements would direct expression of the foreign class I molecules only to B and T lymphocytes. However, expression was also detected in a subset of thymus medullary epithelium. The Kb molecules expressed on this thymic subset were unable to positively select T cells for passage to the periphery. The mice were, however, tolerant of the cell types expressing the foreign Kb molecules and were also tolerant of Kb presented as skin grafts. These results suggest that not all components of thymic epithelium are involved in positive selection of T cells and that transplantation antigens expressed on non-dendritic cells can induce tolerance.

Animals↗
PubMed1990

Low-dose aspirin. II. Relationship of angiotensin II pressor responses, circulating eicosanoids, and pregnancy outcome.

Forty pregnant women (28 to 32 weeks' gestation) were given low-dose aspirin therapy (81 mg/day) from the time of enrollment until delivery; circulating eicosanoid levels and angiotensin II pressor responses were measured before and after 1 week of aspirin therapy. Subsequent clinical outcome was correlated with these results. All women had significant reductions in serum and plasma thromboxane B2 levels with aspirin treatment (p less than 0.01). Eleven women who remained sensitive to the pressor effects of angiotensin II (effective pressor dose less than 10 ng/kg/min) after 1 week of low-dose aspirin treatment exhibited significant decreases (p less than 0.05) in plasma 6-keto-prostaglandin F1 alpha (264 +/- 119 vs 161 +/- 31 pg/ml, mean +/- SD) and prostaglandin E2 (476 +/- 174 vs 351 +/- 112 pg/ml) levels. In contrast, patients who were either nonsensitive (refractory) to angiotensin II (n = 18; greater than or equal to 10 ng/kg/min) before aspirin or became nonsensitive after aspirin administration (n = 11) had no change in either plasma 6-keto-prostaglandin F1 alpha or prostaglandin E2 concentrations. The occurrence of pregnancy-induced hypertension was 100% in the women who remained angiotensin II sensitive during aspirin therapy as compared with 36% and 39% in the other two groups (x2 = 16.14; p less than 0.001). Thus during low-dose aspirin therapy a failure to develop refractoriness to infused angiotensin II is associated with a nonselective inhibition of eicosanoids and the almost certain development of pregnancy-induced hypertension. These observations may reflect a basic defect in vascular adaptation to pregnancy.

6-Ketoprostaglandin F1 alpha↗