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Biomedical subjects

D Mukherjee

Publications and source records attributed to D Mukherjee.

At least 55 records · Page 3Linked to original sources
PubMed2000

Mitral valve surgery in patients with severe left ventricular dysfunction.

OBJECTIVES: The objectives of this study were to determine (1) survival, (2) functional status and freedom from readmission for heart failure and (3) change in postoperative left ventricular (LV) dimensions and function following mitral valve repair or replacement in patients with severe LV dysfunction and mitral regurgitation. PATIENTS AND METHODS: Between 1990 and 1998, 44 patients with mitral regurgitation and a LV ejection fraction <35% (mean+/-SD, 28+/-6%) underwent isolated mitral repair (n=35) or replacement (n=9). The etiology of regurgitation was valvular in 18 (40%) patients, ischemic in 13 (30%) patients and dilated idiopathic cardiomyopathy in 13 (30%) patients. Every patient had been hospitalized one to six times for symptoms of heart failure (mean+/-SD, 2.3+/-1.5). All patients were receiving maximal drug therapy with 15 (34%) in New York Heart Association (NYHA) class III and 12 (27%) in class IV. Seven (16%) patients were initially referred for consideration of transplantation. The mean+/-SD duration of follow-up was 40+/-21 months. RESULTS: One (2.3%) patient died 9 days postoperatively of acute bronchopneumonia. The mean+/-SD duration of ICU and hospital stay was 41+/-34 h and 9+/-3 days, respectively. The 1-, 2- and 5-year survival rates were 89, 86 and 67%, respectively. Heart failure and sudden death accounted for 62% of the late deaths. The NYHA class improved for survivors from 2.8+/-0.8 preoperatively to 1. 2+/-0.5 at follow-up (P<0.0001). Freedom from readmission for heart failure was 88, 82 and 72% at 1, 2 and 5 years, respectively. No patient has been listed for transplantation. CONCLUSIONS: Mitral valve surgery offers symptomatic improvement and survival benefit in patients with severe LV dysfunction and mitral regurgitation. More liberal use of this surgery for cardiomyopathy patients is warranted.

Adult↗
PubMed2000

Influence of insecticides on microbial transformation of nitrogen and phosphorus in Typic Orchragualf soil.

Four insecticides, viz., BHC, phorate, carbofuran, and fenvalerate, were applied at the rate of 7.5, 1.5, 1.0, and 0.35 kg a.i. ha(-)(1), respectively, to investigate their effects on the growth and activities of N(2)-fixing and phosphate-solubilizing microorganisms in relation to the availability of N and P in laterite (Typic Orchragualf) soil. Insecticides in general, and BHC and phorate in particular, stimulated the proliferation of aerobic nonsymbiotic N(2)-fixing bacteria and phosphate-solubilizing microorganisms and also their biochemical activities, such as nonsymbiotic N(2)-fixing and phosphate-solubilizing capacities, which resulted in greater release of available N (NH(4)(+) and NO(3)(-)) and P in soil. All the insecticides were persistent in soil for a short period of time, and the rate of dissipation was highest for fenvalerate followed by phorate, carbofuran, and BHC, depicting the half-lives (T(1/2)) 8.8, 9.7, 16.9, and 20.6 days, respectively. The insecticides followed first-order reaction kinetics during their dissipation in soil.

Insecticides↗
PubMed2000

Applications of monitoring platelet glycoprotein IIb/IIIa antagonism and low molecular weight heparins in cardiovascular medicine.

With the addition of more potent antiplatelet and antithrombin therapies to the armamentarium of the treatment of acute coronary syndromes and percutaneous coronary interventions, monitoring these therapies has become an important interest. Current and evolving technologies to monitor the extent of inhibition of platelet aggregation and activity of factor Xa caused by IIb/IIIa antagonists and low-molecular-weight heparin, respectively, will be covered in this overview. An underlying question to be considered is whether the results generated from monitoring will effect a change that will improve the efficacy (prevent thrombotic events) or reduce adverse events (bleeding) from these potent therapies.

Cardiology↗
PubMed2000

Improvement in right ventricular systolic function after surgical correction of isolated tricuspid regurgitation.

Chronic tricuspid regurgitation (TR) may lead to impairment in right ventricular (RV) function. Whether surgical correction results in restoration of normal RV geometry and function is unknown. The purpose of this study was to determine whether surgical correction of TR results in improved RV geometry and function. Measurements of RV areas were made from digitized 4-chamber echocardiographic views. Right ventricular end-diastolic volume (RVEDV), right ventricular end-systolic volume (RVESV), and ejection fraction (EF) were calculated with the single-plane subtraction method. There was a significant decrease in RVEDV (109.06 +/- 12.45 versus 71.63 +/- 6. 83; P =.005) and RVESV (76.2 +/- 9.83 versus 44.5 +/- 5.58; P =.002) and a significant increase in RVEF (0.30 +/- 0.05 versus 0.38 +/- 0. 05; P =.01) at a mean follow-up of 130 +/- 63 days after surgery. These results demonstrate significant remodeling of the right ventricle with reduction in size and improved EF after tricuspid valve surgery.

Adult↗
PubMed2000

Bypass graft to the contralateral internal jugular vein for venous outflow obstruction of a functioning hemodialysis access fistula.

As survival among patients with renal failure improves, vascular access becomes more difficult, and preservation of functioning access increases in importance. Subclavian vein thrombosis associated with a distal arteriovenous fistula can result in massive and debilitating swelling of the affected extremity. We describe a novel crossover bypass grafting procedure to the contralateral internal jugular vein in a patient with a thrombosed internal jugular and subclavian vein. This procedure resulted in preservation of the functioning arteriovenous fistula and resolution of the symptoms. Unlike previously described crossover procedures to the contralateral basilic or axillary veins, this bypass graft has the added benefit of not obviating future fistula creation in that extremity.

Arm↗
PubMed2000

Stimulation of pregnenolone metabolism and aromatase activity by luteinizing hormone in mouse uterus.

In vitro metabolism of pregnenolone (P5) as well as production of 17beta-estradiol (E2) were studied in uteri of untreated and luteinizing hormone (LH)-treated mice that had been ovariectomized (OVX) at late-diestrus stage. In the uteri of untreated mice, [H]pregnenolone was shown to be metabolized to Delta-components such as 17alpha-hydroxypregnenolone (17alpha-P5) and dehydroepiandrosterone (DHEA), whereas LH treatment resulted in significant increases in the formation of progesterone (P4), 17alpha-hydroxyprogesterone (17alpha-P4), androstenedione (AD) and testosterone (T). This was assessed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). The content and release of P4 was shown to be stimulated by LH. Trilostane, an inhibitor of 3beta-hydroxysteroid dehydrogenase (3beta-HSD), inhibited LH-induced P4 synthesis and its release in a dose-dependent manner. A considerable increase in [H]estradiol formation from [H]testosterone was recorded in LH-stimulated uterine tissue as compared with the control, indicating the stimulatory effect of LH on aromatase activity. LH-stimulation in the synthesis of P4 and E2 in OVX mouse uteri was mimicked by dbcAMP (cell-permeable cAMP). Incubation with LH was shown to augment the conversion of P4 to various delta-3-oxosteroids. In vitro effects of LH on the synthesis and metabolism of P4, as well as on the stimulation of aromatase activity, were more pronounced in the uterine tissue of LH-primed OVX mice. Thus the results of the present study indicate that, under specific conditions, the uterus of the mouse behaves like steroidogenic tissue. Its prompt response to LH reveals the probable physiological relevance of the existence of LH receptors of high binding affinity in the uterine tissue of the mouse, as reported earlier.

Androstenedione↗
PubMed2000

Monitoring antiplatelet therapy: What is the best method?

Platelet function tests measure different aspects of platelet function, which include adherence, activation, aggregation and secretion. Clinically, the goal of platelet function testing is to provide information about the platelet contribution to the risk of thrombotic or haemorrhagic events and the optimisation of antiplatelet therapy. The important clinical questions are whether an antiplatelet agent is having the desired effect on platelet inhibition (effectiveness) and whether the patient has sufficient residual platelet function to avoid bleeding (safety). The role of aspirin (acetylsalicylic acid) and thienopyridines is well established in the management of patients with coronary artery disease and in the setting of coronary interventions. The last several years have demonstrated the unequivocal effectiveness of intravenously administered platelet glycoprotein (GP) IIb/IIIa antagonists in the management of acute coronary syndromes and in the setting of percutaneous coronary interventions. With the increasing use of these GPIIb/IIIa antagonists, it is becoming more important clinically to measure platelet inhibition with these agents. This paper reviews major techniques and instrumentation for platelet monitoring and discusses the goals of the best method.

Humans↗
PubMed2000

'Rescue' angioplasty for failed thrombolysis.

Early restoration of patency of the infarct-related artery is a universally accepted goal in the treatment of acute myocardial infarction. However, even with the most successful fibrinolytic regimen only approximately 50% of patients achieve restoration of normal flow at 90 minutes. "Rescue" angioplasty, the mechanical reopening of an infarct-related artery after unsuccessful fibrinolytic therapy, appears to be beneficial.

Angioplasty, Balloon, Coronary↗
PubMed2000

Unexpected mortality reduction with abciximab for in-stent restenosis.

Treatment of in-stent restenosis is generally considered low risk, and it is not clear if adjunctive use of abciximab is beneficial in this low-risk population. We determined the effect of adjunctive abciximab during percutaneous coronary intervention (PCI) for treatment of in-stent restenosis. Two hundred and ninety-three patients with in-stent restenosis underwent PCI at the Cleveland Clinic between January 1996 and December 1998. Patients undergoing directional atherectomy, laser treatment and brachytherapy were excluded (9 patients). Of the remaining 284, seventy-nine patients received abciximab during PCI and 205 were treated without abciximab. The groups were similar with respect to age, gender, left ventricular function, number of vessels involved, history of prior coronary artery bypass grafting and unstable symptoms at presentation. There were more diabetics, hypertensives, and patients with elevated cholesterol in the abciximab-treated group. At 1-year follow-up, there was a significantly lower incidence of myocardial infarction (2.5% versus 5.3%; p < 0.05) and lower mortality (1.2% versus 5.8%; p < 0.01) in the abciximab-treated group. There was no difference in the incidence of revascularization. The findings of a lowered mortality and myocardial infarction rate with abciximab warrants further prospective study in patients with in-stent restenosis.

Abciximab↗
PubMed1999

Transcription initiation at the TATA-less spliced leader RNA gene promoter requires at least two DNA-binding proteins and a tripartite architecture that includes an initiator element.

Eukaryotic transcriptional regulatory signals, defined as core and activator promoter elements, have yet to be identified in the earliest diverging group of eukaryotes, the primitive protozoans, which include the Trypanosomatidae family of parasites. The divergence within this family is highlighted by the apparent absence of the "universal" transcription factor TATA-binding protein. To understand gene expression in these protists, we have investigated spliced leader RNA gene transcription. The RNA product of this gene provides an m(7)G cap and a 39-nucleotide leader sequence to all cellular mRNAs via a trans-splicing reaction. Regulation of spliced leader RNA synthesis is controlled by a tripartite promoter located exclusively upstream from the transcription start site. Proteins PBP-1 and PBP-2 bind to two of the three promoter elements in the trypanosomatid Leptomonas seymouri. They represent the first trypanosome transcription factors with typical double-stranded DNA binding site recognition. These proteins ensure efficient transcription. However, accurate initiation is determined an initiator element with a a loose consensus of CYAC/AYR (+1), which differs from that found in metazoan initiator elements as well as from that identified in one of the earliest diverging protozoans, Trichomonas vaginalis. Trypanosomes may utilize initiator element-protein interactions, and not TATA sequence-TATA-binding protein interactions, to direct proper transcription initiation by RNA polymerase II.

Animals↗
PubMed1998

On local(ly) ESS of a pair of prey-predator system with predatory switching.

This paper concentrates on the study of ecological stability for guaranteeing evolutionary stable strategies (ESS) in a two pre-predator system taking into consideration of handling time, with predatory switching. Here predators are polyphagous in nature. The conditions for ESS of the model system are obtained at the equivalence point. We also derive the invasion conditions of a mutant predator.

Animals↗