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Biomedical subjects

S Porter

Publications and source records attributed to S Porter.

At least 91 records · Page 5Linked to original sources
PubMed1997

HIV prevalence in dental outpatients in Brazil.

A series of dental outpatients in Brazil was anonymously screened for HIV antibodies in whole unstimulated saliva with an immunoglobulin G antibody-capture enzyme-linked immunosorbent assay. Salivary HIV antibodies were detected in 40 patients in the control group who were known to be HIV-seropositive but were not detected in any of a series of 40 known HIV-seronegative patients in the control group, confirming the very high sensitivity and specificity of the immunoglobulin G antibody-capture enzyme-linked immunosorbent assay. Only one patient from 84 consecutive dental outpatients of unknown HIV serostatus who were examined anonymously for HIV by immunoglobulin G antibody-capture enzyme linked immunosorbent assay showed HIV positivity (1.2% of the population).

Adolescent↗
PubMed1997

Catecholamine modulatory effects of nepicastat (RS-25560-197), a novel, potent and selective inhibitor of dopamine-beta-hydroxylase.

1. Inhibitory modulation of sympathetic nerve function may have a favourable impact on the progression of congestive heart failure. Nepicastat is a novel inhibitor of dopamine-beta-hydroxylase, the enzyme which catalyses the conversion of dopamine to noradrenaline in sympathetic nerves. The in vitro pharmacology and in vivo catecholamine modulatory effects of nepicastat were investigated in the present study. 2. Nepicastat produced concentration-dependent inhibition of bovine (IC50 = 8.5 +/- 0.8 nM) and human (IC50 = 9.0 +/- 0.8 nM) dopamine-beta-hydroxylase. The corresponding R-enantiomer (RS-25560-198) was approximately 2-3 fold less potent than nepicastat. Nepicastat had negligible affinity (> 10 microM) for twelve other enzymes and thirteen neurotransmitter receptors. 3. Administration of nepicastat to spontaneously hypertensive rats (SHRs) (three consecutive doses of either 3, 10, 30 or 100 mg kg-1, p.o.; 12 h apart) or beagle dogs (0.05, 0.5, 1.5 or 5 mg kg-1, p.o.; b.i.d., for 5 days) produced dose-dependent decreases in noradrenaline content, increases in dopamine content and increases in dopamine/noradrenaline ratio in the artery (mesenteric or renal), left ventricle and cerebral cortex. At the highest dose studied, the decreases in tissue noadrenaline were 47%, 35% and 42% (in SHRs) and 88%, 91% and 96% (in dogs) in the artery, left ventricle and cerebral cortex, respectively. When tested at 30 mg kg-1, p.o., in SHRs, nepicastat produced significantly greater changes in noradrenaline and dopamine content, as compared to the R-enantiomer (RS-25560-198), in the mesenteric artery and left ventricle. 4. Administration of nepicastat (2 mg kg-1, b.i.d, p.o.) to beagle dogs for 15 days produced significant decreases in plasma concentrations of noradrenaline and increases in plasma concentrations of dopamine and dopamine/noradrenaline ratio. The peak reduction (52%) in plasma concentration of noradrenaline and the peak increase (646%) in plasma concentration of dopamine were observed on day-6 and day-7 of dosing, respectively. 5. The findings of this study suggest that nepicastat is a potent, selective and orally active inhibitor of dopamine-beta-hydroxylase which produces gradual modulation of the sympathetic nervous system by inhibiting the biosynthesis of noradrenaline. This drug may, therefore, be of value in the treatment of cardiovascular disorders associated with over-activation of the sympathetic nervous system, such as congestive heart failure.

Animals↗
PubMed1997

Reviewing Foucault: possibilities and problems for nursing and health care.

This paper addresses Foucauldian theory and its usefulness to nursing research. It is written in the form of a discussion between the authors on the merits and liabilities of Foucauldian theory as applied to analyses of nursing. As such, it focuses upon some of the more pertinent critiques of both Foucauldian and postmodern theory. By addressing Foucault from two different positions, the discussion seeks to demonstrate the complexity of Foucauldian theory and warns against over-simplification in its application to nursing research. The authors also argue for an awareness of the strengths and weaknesses of any given theoretical stance.

Humans↗
PubMed1997

Psychiatric dilemmas--surgery and the Mental Health Act (1983).

Clinicians commonly face an ethical conundrum when the patient declines a treatment they believe to be necessary. The decision, whether to give or to withhold treatment, may also have legal repercussions. Two illustrative cases are presented. Although the Mental Health Act (1983) is concerned with treatment of mental disorder, treatments for physical disorders may be given in certain circumstances if the patient is deemed to lack the competence to understand the issues involved in the decision, and treatment is deemed to be in their best interests.

Adult↗
PubMed1997

Bilateral tibial marrow ablation in rats induces a rapid hypercalcemia arising from extratibial bone resorption inhibitable by methylprednisolone or deflazacort.

The goals of this study were to quantitate biochemical markers of bone metabolism on days 1-15 after bilateral tibial marrow ablation surgery in young adult rats and to determine the effect of a single dose of methylprednisolone (2 mg/kg) or deflazacort (2.5 mg/kg) given at the time of ablation. Unexpectedly, serum calcium levels rose to a maximum of 15.9 mg/dl on day 7 after marrow ablation and remained above normal through day 15. This increase was blocked by a single intramedullary injection of methylprednisolone or deflazacort immediately following ablation; however, the fact that both drugs produced a characteristic rapid 3- to 10-fold increase in the serum alpha 2-macroglobulin level demonstrates that the drugs rapidly reached the circulation. Both methylprednisolone and deflazacort also inhibited intramedullary deposition of collagen by 40-60% on day 7, a time near which operated control animals achieved maximal accumulation of new bone in this model. Histological comparisons among the three experimental groups were largely consistent with biochemical results. The urinary hydroxyproline/creatine ratio for the operated control group doubled on day 3 and then returned to presurgical levels on day 7 and later. The timing and size of the hydroxyproline/creatinine peak, as well as the fact that the intratibial osteoclastic response peaks on days 8-10 after ablation, suggests it results from extratibial bone resorption induced by marrow ablation. Consistent with this rationale, urinary calcium excretion in operated controls rose 9-fold from day 0 to day 3 and appeared to plateau over the period from day 3 to day 9, before returning to a near presurgical level on day 15. Elevated excretion of calcium noted on days 9-15 in deflazacort-treated animals, which occurs in the absence of a detectable increase in resorption marker hydroxyproline, may however be due to the known action of glucocorticoids in increasing kidney filtration of calcium. In summary, this is the first report to show that bilateral tibial marrow ablation in rats causes a rapid hypercalcemia and calciuria which is accompanied initially by a peak of bone resorption marker urinary hydroxyproline. We speculate that the source of calcium and hydroxyproline is extratibial osteoclastic bone resorption induced by circulating cytokines whose release from ablated tibias or osteoclastogenic action is inhibitable by methylprednisolone and deflazacort.

Animals↗
PubMed1996

The Gfi-1 protooncoprotein represses Bax expression and inhibits T-cell death.

The Gfi-1 protooncogene encodes a nuclear zinc-finger protein that carries a novel repressor domain, SNAG, and functions as a position- and orientation-independent active transcriptional repressor. The Gfi-1 repressor allows interleukin 2 (IL-2)-dependent T cells to escape G1 arrest induced by IL-2 withdrawal in culture and collaborates with c-myc and pim-1 for the induction of retrovirus-induced lymphomas in animals. Here we show that overexpression of Gfi-1 also inhibits cell death induced by cultivation of IL-2-dependent T-cell lines in IL-2-deficient media. Similarly, induction of Gfi-1 in primary thymocytes from mice carrying a metal-inducible Gfi-1 transgene inhibits cell death induced by cultivation in vitro. The protein and mRNA levels of the proapoptotic regulator Bax are down-regulated by Gfi-1 in both immortalized T-cell lines and primary transgenic thymocytes. The repression is direct and depends on several Gfi-1-binding sites in the p53-inducible Bax promoter. In addition to Bax, Gfi-1 also represses Bak, another apoptosis-promoting member of the Bcl-2 gene family. Therefore, Gfi-1 may inhibit apoptosis by means of its repression of multiple proapoptotic regulators. The antiapoptotic properties of Gfi-1 provide a potential explanation for its strong collaboration with c-myc during oncogenesis.

Animals↗
PubMed1996

Mucosal lesions due to oral cocaine use.

Cocaine abuse is a major public health problem worldwide and is increasingly common in Europe. Oral use of cocaine in two patients resulted in unusual white lesions on their anterior maxillary gingivae/vestibule. GDPs should be alert to this newly described lesion.

Administration, Oral↗
PubMed1996

Allelic imbalance on chromosome 3p in oral dysplastic lesions: an early event in oral carcinogenesis.

We have demonstrated previously a loss of constitutional heterozygosity on the short arm of chromosome 3 in approximately 50% of oral squamous cell carcinomas. In the present study, we have investigated 30 oral dysplastic lesions (DLs), presenting clinically as either erythroplakias or leukoplakias with histopathological features of either severe epithelial dysplasia or carcinoma in situ, for LOH on chromosome 3p using 15 microsatellite markers. Thirteen of the 30 LDs (approximately 43%) showed allelic imbalance at one or more loci. The pattern of loss in these lesions defined three noncontiguous regions of interstitial deletions that overlap with those defined for oral squamous cell carcinomas. These data indicate that the alteration of tumor suppressor genes on chromosome 3p is probably an early event in oral carcinogenesis. Additionally, 7 of the 30 DLs showed microsatellite instability. However, the frequency of loci showing microsatellite instability per lesion was low.

Alleles↗
PubMed1996

Why teach sociology? A contribution to the debate.

This paper seeks to engage in the debate about the role of sociology in nurse education that has been conducted in the pages of Nurse Education Today by Hannah Cooke (1993) and Keith Sharp (1995). Cooke's paper is addressed first. It is argued that in her application to nursing of Foucauldian notions of power, Cooke inflates the salience of power to the development of holistic care. In doing do, she diverts her argument away from the central problematic of her paper, namely her identification of critical structural approaches as being essential to nursing sociology. Cooke's conclusions on this issue are defended against the attack made upon them by Sharp. First, it is contended that Sharp's argument that the multiparadigmatic nature of sociology means that it cannot act as a guide for nurses is self-contradictory. Second, it is argued that his characterization of nursing work as essentially instrumental is misguided, in that the prosecution of holistic care entails a more reflexive form of action. Finally, it is posited that his interpretation of Cooke's perspective as narrow political vision is unsustainable.

Education, Nursing↗
PubMed1996

Multiple hamartoma syndrome presenting with oral lesions.

Multiple hamartoma syndrome (Cowden's syndrome), a rare genodermatosis with predominant mucocutaneous features, particularly hamartomas, and Cowden/Lhermitte-Duclos disease, the combination of multiple hamartomas with cerebellar hypertrophy, typically present with cutaneous and oral papillomatosis as major features of both uncommon disorders. This article details the clinical features of three patients with multiple hamartoma syndrome and one with both disorders.

Adult↗
PubMed1996

Trends in survival from cancers of the oral cavity and pharynx in Scotland: a clue as to why the disease is becoming more common?

Data were examined to determine trends in survival from cancers of the oral cavity and pharynx in Scotland between 1968 and 1987, and to analyse survival rates and the previously noted increases in the incidence of such cancers according to the level of social deprivation. Incidence data on oral cavity and pharyngeal cancer and survival rates following diagnosis were obtained from the Information and Statistics Division of the Common Services Agency for the National Health Service in Scotland, covering the period 1968-92. It was found that survival rates for cancers of the tongue, mouth and pharynx diagnosed among persons less than 65 years of age decreased between 1968-72 and 1983-87. Five year relative survival rates fell from 47% to 39% over this period, while the equivalent rates among persons older than 65 years have shown a modest improvement from 34% to 38%. When considered by level of social deprivation, survival is lower among persons from the most deprived areas, and it is among such persons that the recent increases in occurrence of cancers of the oral cavity and pharynx have primarily occurred. The poorer survival among those from more socially deprived areas, and the evidence that the largest increase in incidence has occurred in such areas may to some extent explain the non-favourable trends in mortality. More importantly it emphasises the potential benefits of targeting such a population for oral health information. An educational campaign should include both information on the risk factors for developing oral cancer, and also the importance of seeking an early professional consultation in the case of symptoms.

Aged↗
PubMed1996

Breaking the boundaries between nursing and sociology: a critical realist ethnography of the theory-practice gap.

This paper is a response to the challenges laid down by Hannah Cooke in a paper in the Journal of Advanced Nursing entitled "Boundary work in the nursing curriculum: the case of sociology' (Cooke 1993a). In her paper, Cooke noted that the outlook of nursing and sociology are inimicable because nursing's concentration on individuals is at variance with sociology's concern with wider social issues. We argue that it is possible for nursing research to give due attention to social structures without losing its focus on individuals. One methodology that could facilitate this broadening of nursing's epistemological boundaries is critical realist ethnography, which works under the assumption that the relationship between social structures and individual actors involves a two-way process, in that while the enablements and constraints imposed by structures influence individual actions, those actions in turn either maintain or transform social structures. To demonstrate how such a methodology could be applied in nursing research, we work through a case study concerning the theory-practice gap, arguing that the gap is neither the result of clinicians' ignorance of nor antipathy to theory, but is largely generated by the lack of resources enjoyed by nurses, which in turn is a reflection of the social structure of capitalism within which nurses operate.

Anthropology, Cultural↗