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Biomedical subjects

P Stewart

Publications and source records attributed to P Stewart.

At least 91 records · Page 5Linked to original sources
PubMed1994

Occupation and ovarian cancer: a case-control study in the Washington, DC, metropolitan area, 1978-1981.

Ovarian cancer risk factors may be genetic, reproductive, or hormonal in nature. Occupational exposure to talc and other carcinogenic substances has not been studied in relation to ovarian cancer risk. We therefore examined the job histories of 296 women aged 20 to 79 who were diagnosed with epithelial ovarian cancer in the Washington, DC area in 1978 to 1981, comparing them to 343 hospital controls, matched for age and race. A blind exposure assessment, evaluating each job/industry combination for potential exposure to talc, ionizing radiation, polycyclic aromatic hydrocarbons, and solvents was conducted by an industrial hygienist blind to case-control status. Women exposed to talc had a relative risk of ovarian cancer below the null, but the confidence interval was wide and there was no evidence of a trend. Women exposed to polycyclic aromatic hydrocarbons had an elevated relative risk, also with a wide confidence interval and no evidence of a trend with duration.

Adult↗
PubMed1994

Continuity of care and desipramine in primary cocaine abusers.

The objective of this research was to determine the efficacy of enhanced continuity of care and desipramine in increasing treatment attendance and abstinence from cocaine in primary cocaine abusers. Study design was a random assignment, placebo-controlled factorial with assessments at baseline and at 3 (first week of outpatient treatment), 8, and 12 weeks after start of study. Desipramine blood levels were taken at weeks 2 (inpatient), 3, and 8. Subjects (N = 94 men) were recruited on an inpatient ward and assigned to increased continuity of care or to standard treatment, and to active or placebo drug. Main outcome variables were toxicology-verified reports of cocaine use, and attendance at counseling sessions. Enhanced continuity of care increased abstinence from cocaine at week 3 and increased attendance at individual counseling sessions throughout the 12 weeks of the study. There were no main effects for desipramine. Blood levels above 123 ng/ml at week 2 predicted longer stays in outpatient. We conclude that enhanced continuity of care is a low cost intervention that improves early treatment outcome and attendance; desipramine effects do not warrant its therapeutic use.

Adult↗
PubMed1992

Secretion of breast gross cystic disease fluid proteins by T47D breast cancer cells in culture--modulation by steroid hormones.

The effect of steroid hormones on modulating the secretion rates of three human breast gross cystic disease fluid proteins (GCDFP-15, GCDFP-24, and GCDFP-44) by T47D breast carcinoma cells in tissue culture was evaluated. Androgens (dihydrotestosterone or fluoxymesterone) were capable of stimulating the secretion rates for all three GCDFP's while showing a minimal trend toward slowing the growth rate of T47D cells. This is the first study which shows that androgens can specifically stimulate all three of the major breast GCDFP's concomitantly. Progesterone, and three synthetic progestins, all showed inhibition of the growth rate of T47D cells while causing enhancement of the secretion of GCDFP-15 and GCDFP-44, and only minimal effect on the secretion rate of GCDFP-24. Estradiol was essentially neutral to the growth rate of the T47D cells in our test system. Estradiol did cause a mild enhancement of GCDFP-44 secretion rate, with no appreciable effect on GCDFP-15 or GCDFP-24 secretion rates. These findings suggest that an androgenic stimulus may be involved in the secretion of GCDFP's associated with breast gross cystic disease.

Adipokines↗
PubMed1992

The repetitive vascular catastrophes of Behçet's disease: a case report with review of the literature.

Behçet's disease is a chronic, recurrent disease that most commonly presents as oral and genital ulcers and iritis. It is a multisystem disease with possible cardiovascular, pulmonary, neurologic, cutaneous and articular involvement. It is most often diagnosed in the 20 to 40 year age group, and vascular and neurologic involvement worsens the prognosis. Vascular manifestations include venous and arterial occlusions, arterial aneurysm and pseudoaneurysm formation. We present the case of a young man with Behçet's disease with multiple aneurysms, pseudoaneurysms, arterial occlusions and venous thrombosis with a literature review. Surgeons must consider Behçet's disease when dealing with aneurysms in young patients.

Adult↗
PubMed1992

Functional and morphological changes induced by tunicamycin in dividing and confluent endothelial cells.

Cultured bovine aortic endothelial cells treated with tunicamycin, an inhibitor of glycoprotein synthesis, developed a concentration-dependent inhibition of N-acetylglucosamine-1-phosphate transferase activity, and this inhibition was correlated with a substantial decrease in [3H]mannose incorporation by the cells. Endothelial cells were very sensitive to tunicamycin, and changes in their morphology occurred as a result of the inhibition of glycoprotein synthesis. The cells became elongated, the surface irregular, roughened, and granular, and there was an increase in the interstitial space between the cells. Electron dense material was accumulated within and dilated the rough endoplasmic reticulum, and the distribution of the glycoproteins laminin and fibronectin throughout the endothelial cell monolayer was modified. These morphological changes coincided with functional impairment with the permeability of endothelial cell monolayers to both 125I-albumin and [3H]inulin being increased by treatment with tunicamycin (10(-6) M) for 24 h. These results indicate that the synthesis of glycoproteins is crucial for cell-cell adhesion and the functional properties of the endothelial lining of blood vessels.

Albumins↗
PubMed1992

Treatment of acute graft-versus-host disease with a nonmitogenic anti-CD3 monoclonal antibody.

Treatment with the monoclonal antibody OKT3 specific for the CD3 complex associated with the T cell antigen receptor can reverse acute rejection of human renal allografts. However, efficacy of anti-CD3 antibodies for treatment of patients with acute graft-versus-host disease after marrow transplantation has not been established. The dose-limiting side effects resulting from T cell activation induced by some anti-CD3 antibodies in vivo have discouraged their use for this application. We now report a phase I-II study of GVHD treatment with the anti-CD3 antibody BC3, a monoclonal murine IgG2b that, unlike OKT3, does not activate T cells. Fourteen patients were treated with BC3 after progression of acute GVHD despite treatment with cyclosporine and corticosteroids, and three patients received BC3 as primary treatment for GVHD. BC3 was administered at a dose of 0.1 or 0.2 mg/kg/day for seven or eight days. Five patients achieved complete resolution of GVHD, eight patients had partial improvement, two patients had no change, and two patients had progression of GVHD on therapy. Responses were sustained in 8 of 13 patients. Mild chills, fever, hypertension, and chest discomfort occurred in various combinations following 6 of 17 (35%) initial infusions of BC3 and following 4 of 99 (4%) subsequent infusions. In each instance it was possible to continue BC3 therapy without adjusting the dose or treatment schedule. In each patient treated, the absolute count of peripheral blood lymphocytes decreased transiently but returned to baseline within 22 hr after the first infusion. Circulating T cells had surface CD3 molecules saturated by the infused antibody in all but one patient. Four patients survived longer than one year after treatment with antibody BC3, and 13 patients died of infection or organ failure. Administration of the nonmitogenic anti-CD3 antibody BC3 was associated with improvement in the clinical manifestations of GVHD with minimal acute toxicity. Efficacy of antibody treatment did not depend on depletion of circulating T cells. Therefore, antibody BC3 may be achieving therapeutic immunosuppression by modulating T cell function. Controlled studies in patients treated earlier in the course of GVHD should determine whether antibody BC3 can improve survival.

Adult↗
PubMed1992

Lignin peroxidase gene family of Phanerochaete chrysosporium: complex regulation by carbon and nitrogen limitation and identification of a second dimorphic chromosome.

Lignin peroxidases (LiP) of Phanerochaete chrysosporium are encoded by a family of six closely related genes. Five LiP genes have been localized to the same dimorphic chromosome. In this investigation, relative transcript levels of the LiP genes were determined. Transcripts of the LiPA, LiPB, and O282 genes were at similar levels in both carbon- and nitrogen-limited cultures. In contrast, transcription of the GLG5, V4, and GLG4 genes was dramatically altered by culture conditions. Under carbon-limited conditions, GLG4 transcripts were, by far, the most abundant. Southern blot analyses of clamped homogeneous field gels were used to map the GLG4 gene to a dimorphic chromosome separate from the other LiP genes.

Base Sequence↗
PubMed1992

[Idiopathic dilatation of the right atrium diagnosed in utero].

It is described one case of extreme right atrium dilatation detected in utero, as an isolated abnormality. Ebstein's anomaly was first suspected because in-utero tricuspid regurgitation detected with Doppler two dimensional echocardiography. Soon after birth and thereafter no tricuspid regurgitation could be find and no symptoms are present, despite the giantly dilated right atrium. The aetiology of this abnormality is discussed and the benign course emphasized.

Adult↗
PubMed1991

A strychnine-sensitive site is involved in dynorphin-induced paralysis and loss of the tail-flick reflex.

Dynorphin A(1-13) administered intrathecally to rats induces a reversible hindlimb paralysis and permanent loss of the tail-flick reflex in a dose-dependent and all-or-none manner. The loss of the tail-flick reflex has been determined to result from neurotoxicity linked to the N-methyl-D-aspartate (NMDA) receptor. Recently, it has been reported that NMDA antagonists attenuate irreversible paralysis induced by dynorphin A(1-17) and dynorphin A(2-17). In the present studies, we examined whether repeated injections of dynorphin A(1-13) acetate salt could change the characteristics of the reversible paralysis. Injections repeated every 48 h resulted in hindlimb paralysis upon each injection which was not different in terms of magnitude or duration (P greater than 0.60). Injections repeated at 2 h intervals resulted in desensitization of the paralytic effects (P less than 0.05). We also examined if strychnine sulfate, a glycine antagonist would alter the paralytic response to dynorphin. Strychnine protected rats from paralysis (P less than 0.01) and loss of the tail-flick reflex with an ED50 of 7 nmol. We conclude that the reversible paralysis induced by dynorphin A(1-13) is repeatable which suggests that the paralysis results from nontoxic or subtoxic actions of dynorphin. Desensitization to the paralytic effects occurs with closely spaced injections by some unknown mechanism. In addition, we conclude that the spinal glycinergic inhibitory system may participate in the induction of the paralysis because strychnine antagonizes dynorphin-induced paralysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Consumer interest in alternatives to physician-centred hospital birth in Ottawa.

A survey of 1109 women who delivered in a hospital or at home in a major city in Canada was conducted. The women were asked to respond to questions concerning the type of health professional they would like to provide reproductive care. The choices they were offered were: midwife, obstetrician, general practitioner or nurse, or a combination. Respondents were also asked to identify if they had an interest in an alternative such as a birthing room, birthing centre or home birth, to hospital labour ward care. Almost 60% of women were interested in some form of midwifery care with the major emphasis placed on counselling and support. Of the women who expressed an interest in midwifery services a large number elected for that service to be shared with an obstetrician. Women who were older and had achieved a high level of education were more interested in midwifery services than other women. If given choices of a hospital labour, birthing room, birthing centre or home birth 53% of women would choose to give birth in a hospital labour ward. A major reason for this choice was the accessibility of epidural analgesia. The majority of women who had experienced a home birth would make the same choice again. There was a strong positive association between interest in using midwifery services and interest in a birthing centre and home birth.

Adolescent↗