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Biomedical subjects

D Roy

Publications and source records attributed to D Roy.

408 records · Page 23Linked to original sources
PubMedDate not supplied

Regulation of the growth of mouse Leydig cells by the inactive stereoisomer, 17alpha-estradiol: Lack of correlation between the elevated expression of ERalpha and difference in sensitivity to estradiol isomers.

We examined the effects of 17alpha-estradiol, the biologically inactive stereoisomer of 17beta-estradiol, on cell growth and cell cycle kinetics using the normalized mouse TM3 Leydig cells. A significant biphasic stimulatory growth response was observed by 17alpha-estradiol exposure with peaks at 1 pg/ml (157.13%) and 100 ng/ml (120.04%) (p<0.05). The growth stimulatory effects of 17alpha-estradiol were inhibited by tamoxifen. A significant decrease in cell cycle time of Leydig cells exposed to 17alpha-estradiol was observed in treated cells (p<0.05). RT-PCR analysis indicated that exposure to Leydig cells to 1 pg/ml and 100 ng/ml 17alpha-estradiol resulted in a 10- and 5-fold increases in the expression of ERalpha, respectively. Similar effects were observed with exposure to equivalent concentrations of 17beta-estradiol. Difference in sensitivity to stereoisomers of estradiol to growth response of Leydig cells did not correlate with the elevated expression of ERalpha. We conclude that the TM3 Leydig cells are sensitive to the non-typical estrogen, 17alpha-estradiol, presumably through the activation of ER-independent signaling transduction pathways.

Animals↗
PubMedDate not supplied

Long-term performance of single-pass physiological pacing.

BACKGROUND: Single-pass physiological pacing has several advantages over dual-lead physiological pacing. The present study evaluated the long-term performance of single-pass pacing using the overlapping biphasic impulse stimulation technique. METHODS AND RESULTS: A total of 30 patients with single-pass VDD pacing and 8 patients with single-pass DDDC pacing were followed up for 1 year by basal and magnet electrocardiograms and real-time telemetry. All the patients showed satisfactory atrial sensing and pacing capture threshold. The atrial sensing thresholds at implant and at 1 month, 3 months, 6 months and 12 months of follow-up were 2.5+/-0.67 mV, 1.6+/-0.6 mV, 1.1+/-0.5 mV, 1.0+/-0.5 mV and 1.0+/-0.04 mV, respectively. The corresponding values for atrial pacing threshold at a pulse wave of 0.5 ms were 2.5+/-1.0 V, 4.4+/-0.9 V, 3.8+/-1.2 V, 3.6+/-1.4 V and 3.8+/-1.4 V. Of the patients with DDDC pacing, 88% showed stable pacing capture in the supine position, 75% in the upright position and 62% in both positions. Diaphragmatic contraction was seen in 25% of cases with DDDC pacing. No such event was seen in patients with VDD pacing. CONCLUSIONS: Single-pass pacing is safe, technically easy and cheap as compared to dual-lead systems. However, it would be prudent to recommend DDDC pacing in patients who require predominantly VDD pacing and only occasionally atrial pacing, as the latter showed a low percentage of stable atrial pacing capture in both upright and supine positions as well as a significant percentage of diaphragmatic contraction.

Adult↗
PubMedDate not supplied

[Health promotion: application of the Ottawa Charter].

One of the greatest challenges for community health today is to translate the health promotion framework into specific actions. An essential step toward integration of the strategies suggested by the Ottawa Charter for Health Promotion lies in a close scrutiny of community health practice by health professionals. In the context of our own organization, we have set up a series of policy development seminars designed to bring together staff involved in different areas of community health and to have them work through clear institutional positions regarding current public health issues. We examined the policy positions in the light of the Ottawa Charter. Some of the Charter's suggested strategies were not well covered by the seminar participants. This could be partly attributed to the traditional mix of disciplines in community health. In order to approach health as defined in the Charter, a novel mix of disciplines should be invited to collaborate with the already existing professionals. The Charter is a useful tool for better focusing community health practice onto the health promotion paradigm.

Alcohol Drinking↗
PubMedDate not supplied

Electrophysiologic effects of intravenous diltiazem in patients with recurrent supraventricular tachycardias.

The electrophysiologic effects of intravenous diltiazem were evaluated in 10 patients with recurrent supraventricular tachycardias. The tachycardia incorporated an accessory pathway in 7 patients and was due to AV nodal reentry in 3 patients. Diltiazem 0.25 mg/kg was administered intravenously over 5 minutes during sustained supraventricular tachycardia. Programmed electrical stimulation was used to restore sinus rhythm if diltiazem failed to terminate the arrhythmia within 10 minutes. Conduction intervals, refractory periods and tachycardia characteristics were evaluated before and immediately after drug administration. Diltiazem did not significantly modify sinus cycle length, AH and HV intervals. Atrial and ventricular effective refractory periods were similar before and after diltiazem. The effective refractory period of the AV node was prolonged by 42 msec after diltiazem (p less than 0.05). Diltiazem increased the tachycardia cycle length from 320 +/- 41 to 353 +/- 36 msec (p less than 0.01) but terminated the arrhythmia in only 2 patients. After diltiazem, supraventricular tachycardia could not be reinitiated in only 2 patients and the tachycardia initiating window was not significantly reduced (56 +/- 26 to 41 +/- 33 msec). The infusion of diltiazem was accomplished without side effects. Thus, 0.25 mg/kg of intravenous diltiazem produces a modest depression of AV nodal function and is not very effective in terminating supraventricular tachycardia or preventing its initiation in this study population. Further studies using higher doses of intravenous diltiazem would be useful to determine its maximal therapeutic benefit in patients with recurrent supraventricular tachycardias.

Adult↗
PubMedDate not supplied

Efficacy of diltiazem in recurrent supraventricular tachyarrhythmias.

Diltiazem alters human atrioventricular nodal properties in a dose and rate-dependent manner. Intravenous diltiazem is effective in converting supraventricular tachycardia to sinus rhythm. It may be a very useful drug for sustained control of heart rate in patients with rapid atrial fibrillation. The recommended intravenous dose is 0.25 mg/kg given over 2 mins followed by a maintenance infusion of 5 to 15 mg/h. Clinical data on the electrophysiological effects of oral diltiazem are limited. The oral form may be used as an alternative agent for the prophylaxis of recurrent supraventricular tachycardia.

Administration, Oral↗
PubMedDate not supplied

The care programme approach at work in mental health care.

The care programme approach provides a system whereby the client is placed at the centre of everything professionals do. A client's action plan is drawn up, with the role of each professional made explicit, including the time of his or her involvement. Finally, a date is set to review the package of care. This paper aims to show how such a system has been applied and provides an example through a care study.

Aftercare↗