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Biomedical subjects

S Porter

Publications and source records attributed to S Porter.

At least 73 records · Page 4Linked to original sources
PubMed1998

Initial employment experience of 1996 graduates of diagnostic radiology and radiation oncology training programs.

OBJECTIVE: The American College of Radiology sought to detail the initial employment experience of 1996 diagnostic radiology and radiation oncology graduates, the actual effect of factors expected to generate poor employment outcomes, and trends since 1995. MATERIALS AND METHODS: In autumn 1996, questionnaires were mailed to all graduates; 69% responded. The results were compared with a similar survey of 1995 graduates. RESULTS: After graduation, 3-10% of graduates, depending on their field (diagnostic radiology or radiation oncology) and level (residency or fellowship), spent some time working as a locum tenens, working outside their field, or unemployed. However, by a year after graduation, working outside one's field and unemployment had virtually disappeared, even among graduates unable or unwilling to relocate. The Professional Bureau of the American College of Radiology was the most widely used major job search method and drew relatively favorable ratings. At least 15-22% of graduates in posttraining employment had, and disliked, one or more of 11 job characteristics many observers regard unfavorably. Most commonly, the graduates' objection was to having too few patients to remain busy. Relatively poor job outcomes were associated with having a spouse who had to find a job in the same locality as the graduate (only salaries were impaired) but not with other locational constraints, with inadequacy of a major aspect of the training program (as reported by the graduate), and with being female. Changes from 1995 were few, and median salaries were approximately the same as in 1995. CONCLUSION: The employment situation is basically stable, but salaries seem to be lagging behind inflation. Female graduates' poorer employment outcomes are worrisome, especially because studies of women in other professions generally find, unlike our study, that women start their careers even with men.

Adult↗
PubMed1998

Orofacial disease: update for the dental clinical team: 2. Ulcers, erosions and other causes of sore mouth. Part I.

Mouth ulcers are one of the most common oral complaints. The term ulcer is used usually where there is damage to both epithelium and lamina propria, and a crater, sometimes made more obvious clinically by swelling caused by oedema or proliferation in the surrounding tissue. The term erosion is usually used where the damage is somewhat more superficial. Most ulcers/erosions are due to local causes such as trauma or burns. Some are caused by aphthae or malignant neoplasms, and a few have aetiology in obvious systemic disease. Ulcers of local cause, drugs, aphthous ulcers, Behcet's syndrome and malignant ulcers are discussed in this article. The next two articles discuss the ulcers due to systemic disease including disorders of the blood, gastrointestinal disorders, skin diseases, connective tissue disease and infective diseases.

Behcet Syndrome↗
PubMed1997

Determination of Ro 48-3656 in rat plasma by reversed-phase high-performance liquid chromatography. Comparison of 1.5-microm nonporous silica to 3.5-microm porous silica analytical columns.

We describe a method for measuring Ro 48-3656 in EDTA rat plasma by neutral pH, reversed-phase high-performance liquid chromatography using a 1.5-microm nonporous silica, C18 analytical column and UV absorbance detection to support pharmacokinetic studies. We also describe a comparison of the 1.5-microm nonporous silica C18 column versus 3.5-microm porous silica C18 columns. The final method using the 1.5-microm nonporous silica column demonstrated good precision (of both quantification and retention time), accuracy and recovery, linearity of dilution and limit of quantification (40 ng/ml Ro 48-3656 using a 20 microl injection). Samples of neat EDTA rat plasma were prepared by ultrafiltration followed by direct injection onto the HPLC column.

Animals↗
PubMed1997

Deletion mapping defines three discrete areas of allelic imbalance on chromosome arm 8p in oral and oropharyngeal squamous cell carcinomas.

Deletions on chromosome arm 8p, as defined by allelic imbalance, are a frequent event in many different types of malignant tumors, including those of the head and neck. These regions are thought to harbor tumor suppressor genes. In order to define a high-density deletion map of this chromosomal arm in oral and oropharyngeal squamous cell carcinomas, we have tested for allelic imbalance in 35 such tumors with 22 short tandem-repeat polymorphisms. Overall, 21 (60%) of the 35 tumors showed allelic imbalance at one or more loci on chromosome arm 8p. Interstitial deletions defined three discrete areas of deletion: at 8p23, 8p22, and 8p12-p21. Tumors of TNM stages II-IV showed a significantly higher frequency of allelic imbalance on 8p than did TNM stage I tumors. Our data suggest that there are least three tumor suppressor loci on chromosome arm 8p that may be implicated in oral carcinogenesis. Furthermore, inactivation of such genes may be associated with high-grade tumors.

Carcinoma, Squamous Cell↗
PubMed1997

Cardiac troponin I in pediatrics: normal values and potential use in the assessment of cardiac injury.

OBJECTIVE: To establish normal values and determine the impact of congenital or acquired heart disease on serum cardiac troponin I (cTnI). METHODS: Concentrations of cTnI were measured in two groups of children. Group A represented ambulatory pediatric patients with no apparent cardiac disease (n = 120) and patients in stable condition with known congenital or acquired cardiac abnormalities (n = 96); group B was composed of patients admitted to intensive care units with normal echocardiograms (n = 16), with abnormal echocardiograms (n = 36), and those with blunt chest trauma who were thought to have cardiac contusions (n = 7). RESULTS: The cTnI concentrations were generally less than 2.0 ng/ml in group A and frequently below the level of detection for the assay (1.5 ng/ml). There was no statistical difference between the two outpatient subgroups (p = 0.66). Nine intensive care patients had cTnI values greater than 2.0 ng/ml. Six of these patients, all with abnormal echocardiograms, had values less than 7.7 ng/ml. All improved and had subsequent normal cTnI concentrations. None of the three remaining patients (two with systemic illness (trauma and sepsis) and one with severe pulmonary hypertension), all with values greater than 8.0 ng/ml, survived. Three of the four patients with high likelihood of cardiac contusion had cTnI concentrations greater than 2.0 ng/ml (including one patient who died). CONCLUSIONS: Cardiac troponin-I values are generally not elevated in children with stable cardiac disease or general pediatric conditions. In the context of severe acute illness, significant elevation of cTnI may be an indicator of poor outcome. Elevation of cTnI may also have diagnostic value in cases when cardiac contusion is suspected.

Adolescent↗
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↗