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S Shrivastava

Publications and source records attributed to S Shrivastava.

At least 19 recordsLinked to original sources
PubMed2007

The interface between coagulation and immunity.

Coagulation proteases are involved in generating fibrin after vascular injury (hemostasis) but they also have multiple other effects, many of which are mediated independently of fibrin generation, via interactions with specific cell membrane-expressed "protease activated receptors". In inflammation, this family of proteins has a complex influence, the facets of which are still incompletely understood, though a common feature in different models appears to be amplification of innate signals that are initially generated by pathogenic elements or, in the context of transplantation, ischemia or anti-graft antibodies, for instance. There is increasing evidence that these proteases may also have specific effects on cells involved in adaptive immunity and on cells that mediate chronic inflammation and fibrosis. Understanding whether these effects are relevant in the responses generated against transplanted organs is important, as it could lead ultimately to the development of novel ways to promote long-term graft survival.

Animals↗
PubMed2006

Hormonal factors and risk of recurrent venous thrombosis: the prevention of recurrent venous thromboembolism trial.

BACKGROUND: In some but not all studies, men with venous thrombosis had a higher risk of recurrence than women. Information on women with initial hormone-related thrombosis is scant. OBJECTIVE: We assessed the incidence of recurrent thrombosis by gender, and among women using exogenous hormones or pregnant/postpartum at the time of index thrombosis. PATIENTS/METHODS: A total of 508 men and women with one or more previous venous thrombosis episodes were observed while participating in a randomized trial of low-intensity warfarin or placebo for 2.1 years. Index thrombosis events during treatment with postmenopausal hormones, oral contraceptives, or during pregnancy, or the puerperium were considered to be hormone-related events. RESULTS: Among 268 men the 3-year probability of recurrent thrombosis was 18.4% (95% confidence intervals; CI 12.3-24.4). Among 109 women without hormone-related thrombosis, the rate was 15.0% (95% CI 6.3-23.8). Among 129 women with hormone-related thrombosis, the rate was 5.0% (95% CI 1.1-8.9). Adjusting for other risk factors and treatment assignment, women had a 39% lower thrombosis recurrence risk than men: hazard ratio (HR) 0.61 (95% CI 0.34-1.08). Women with hormone-related thrombosis had a 58% lower risk than men: HR 0.42 (95% CI 0.19-0.97); and a 46% lower recurrence risk than other women; HR 0.54 (95% CI 0.19-1.54). Women without hormone-related index events had a recurrence rate similar to men; HR 0.83 (95% CI 0.42-1.66). CONCLUSIONS: In this trial population, women had a lower risk of recurrent venous thrombosis than men. This difference was explained by a low risk of recurrence among women with hormone-related index thrombosis.

Aged↗
PubMed2006

D-dimer, factor VIII coagulant activity, low-intensity warfarin and the risk of recurrent venous thromboembolism.

BACKGROUND: Elevated plasma D-dimer and factor VIII coagulant activity (FVIIIc) may be associated with the risk of recurrent venous thromboembolism (VTE). OBJECTIVES: To evaluate D-dimer and FVIIIc as risk factors for recurrent VTE and assess the efficacy of extended low-intensity warfarin (target International Normalized Ratio 1.5-2.0) in preventing recurrence by biomarker level. PATIENTS AND METHODS: In the Prevention of Recurrent Venous Thromboembolism trial, 508 idiopathic VTE patients treated for > or = 3 months with full-intensity warfarin, and who had stopped warfarin for 7 weeks on average, were randomized to low-intensity warfarin or placebo and followed for 2.1 years for recurrent VTE. Prerandomization blood samples were analysed for D-dimer and FVIIIc. RESULTS: One-third of participants had elevated baseline D-dimer (> or = 500 ng mL(-1)) and one-fourth, elevated FVIIIc (> or = 150 IU dL(-1)). Adjusting for other risk factors, the hazard ratios (HRs) for recurrent VTE with elevated D-dimer or FVIIIc were 2.0 [95% confidence interval (CI) 1.2-3.4] and 1.5 (95% CI 0.8-2.8), respectively. The association of elevated D-dimer with recurrence was larger among patients with one prior VTE (HR 3.2, 95% CI 1.3-8.0) than in patients with more than one event (HR 1.4, 95% CI 0.7-2.2). For patients with one prior VTE on placebo, the annual recurrence incidence was 10.9% with elevated D-dimer and 2.9% with normal values. Low-intensity warfarin was equally effective in recurrence risk reduction in those with normal or elevated biomarkers. CONCLUSIONS: Among patients with idiopathic VTE, measurement of D-dimer, but not FVIIIc, might be useful for risk stratification. The efficacy of extended low-intensity warfarin therapy did not vary by biomarker level.

Adult↗
PubMed2003

Natural history and predictors of moderate mitral regurgitation following balloon mitral valvuloplasty using Inoue balloon.

BACKGROUND: We studied the predictors and natural history of moderate mitral regurgitation following valvuloplasty using Inoue balloon since it has not been well documented in a large series. METHODS: Balloon mitral valvuloplasty was performed in 590 consecutive patients with severe mitral stenosis with mitral regurgitation of mild or lesser grade. Echocardiography and haemodynamics of patients who developed moderate mitral regurgitation were compared with those who did not. They were followed-up. Factors that predicted the development of moderate regurgitation were studied. RESULTS: 21 patients (3.5%) developed moderate regurgitation (identified by auscultation, haemodynamics, angiography and colour flow mapping). They were managed conservatively. At 3 months, regurgitation decreased in severity to mild grade in 12 patients. At 1 year, it was trivial in 5, mild in 11 and remained moderate in 5. There was progressive symptomatic improvement. No clinical, echocardiographic, hemodynamic or procedural variables could predict the development of moderate mitral regurgitation. CONCLUSIONS: Patients with moderate regurgitation after mitral valvuloplasty show gradual improvement in regurgitation and symptoms. There were no factors-clinical, echocardiographic, hemodynamic or procedural-that predicted the occurrence of moderate MR after BMV.

Adolescent↗
PubMed2002

HPV16/18 prevalence in cervical lesions/cancers and p53 genotypes in cervical cancer patients from India.

OBJECTIVES: The HPV16/18 code for an oncoprotein-E6, which binds to p53 tumor suppressor protein and degrades the protein via ubiquitination. A common polymorphism of p53 in exon 4 codon 72, resulting in either proline (Pro) or arginine (Arg), affects HPV16/18 E6-mediated degradation of p53 protein in vivo. Hence, in the current study we investigated the prevalence of HPV16/18 in cervical lesions and the distribution of p53 genotypes in cervical cancers and normal healthy women. METHODS: DNA from 337 Indian women with invasive cervical cancers, 164 women with clinically normal cervix, 64 women with low-grade squamous intraepithelial lesions (LSIL), and 5 women with high-grade squamous intraepithelial lesions (HSIL) was examined for the presence of HPV16/18 using consensus primers in a polymerase chain reaction (PCR), and the specific HPV type was identified by Southern hybridization of the PCR product using HPV16/18 type-specific nucleotide sequences as probes. Further, 134 women with cervical cancers and 131 healthy women were used to determine the frequency of p53 genotypes, Pro/Pro, Arg/Arg, and Pro/Arg, using peripheral blood cell DNA to indicate the constitutional genotypes and allele-specific primers, in a PCR-based assay. RESULTS: We observed a prevalence of HPV16/18 in 77% (258/337) of cervical cancer patients, 38% (24/64) of LSILs, 4 of 5 HSILs, and 15.2% (25/164) of normal healthy women. The frequency of distribution of the three genotypes of p53 codon 72 in a subgroup of the HPV16/18-positive cervical cancer patients was Pro/Pro 0.18 and Arg/Arg 0.26, with the heterozygous Pro/Arg 0.56, differing significantly from the genotype frequency in the normal healthy women (chi(2) = 6.928, df = 2, P < 0.05). CONCLUSIONS: A high prevalence of HPV16/18 was observed in the cervical cancers. The prevalence in LSILs confirms HPV16/18 infection as an early event and further indicates a role in progression of lesions. The p53 genotype distribution indicated that women homozygous for Arg genotype were at a 2.4-fold higher risk for developing HPV16/18-associated cervical carcinomas, compared to those showing heterozygous Pro/Arg genotype (odds ratio 2.4, 95% confidence interval 1.89 to 3.04).

Arginine↗
PubMed2002

Dendrimer grafts for delivery of 5-fluorouracil.

Polyamidoamine (PAMAM) dendrimers were prepared by linking methyl methacrylate and ethylenediamine successively on an amine core. Surface modification of PAMAM dendrimer was done by fatty acid grafting converting them to a unimolecular micellar system (Dendrimer grafts). IR, 1H NMR, 13C NMR studies confirmed the structure. The drug 5-fluorouracil (5-FU) was entrapped in dendrimer grafts. The effects of various solvents (ethanol, dichloromethane, tetrahydrofuran), pH and ionic strength on solubilization of 5-FU were determined. Phospholipid was further coated on the dendrimer grafts. The product was lyophilized and obtained as yellowish-white powder. Average particle size was ca. 375 nm as determined by Malvern's Mastersizer 4. Drug loading was ca. 53% by weight. Stability studies were conducted for 1 month at room temperature and 40 degrees C, where the systems were relatively stable. Release rate was sustained across cellulose tubing in PBS. In vivo studies were performed in albino rats and pharmacokinetic parameters and bioavailability were determined from the plasma profile of 5-FU. The phospholipid coated dendrimer graft formulation was found to be more effective orally than free drug. The lymphatic uptake was also increased indicating absorption of the developed formulation through the lymphatic route.

Administration, Oral↗
PubMed2001

Non-surgical closure of large ductus arteriosus using Amplatzer Duct Occluder feasibility and early follow-up results.

The aim of the study was the assess feasibility of closing large patent arterial ducts (PDA) in infants and children using the new Amplatzer Duct Occluder. All patients diagnosed to be having PDA were considered as potential candidates to undergo the device closure. 19 patients were diagnosed to be having PDA larger than 4 mm. There were 10 males and 9 females, their age ranged from 6 months to 120 months with a mean of 45 months. Mean body weight was 14.5 kg with a range from 7 kg to 23 kg. The procedure was carried out under Ketamine sedation and local anesthesia. The device was implanted by the transvenous route in all. Mean PDA diameter was 5 mm (range 4 mm-6.7 mm). Complete closure was achieved in 16/18 (88%) within 24 hours of the procedure. All patient have been followed for 3 months, and have documented complete closure, there is no evidence of aortic or left pulmonary stenosis in any of our patients. The unsuccessful attempt was in a malnourished patient (weighing 4.7 kg) with an arterial duct measuring 6.7 mm on angiography. This duct was considered too big for device closure and the procedure was abandoned. This patient subsequently has undergone successful surgical ligation. Catheter closure of large PDA in small children is feasible, safe and efficacious. However, it may still not be possible to close large PDA in very small or underweight children, for the fear of causing obstruction to the descending aorta. Further long-term is follow-up required to show sustained benefits without any side effects.

Balloon Occlusion↗
PubMed2001

Left atrial and pulmonary artery wedge pressure monitoring during balloon mitral valvuloplasty.

OBJECTIVE: We tested the accuracy of pulmonary artery wedge (PAW) pressure as a guide to the degree of pulmonary venous hypertension. METHODS: Left atrial (LA) pressure and PAW pressure were analysed before and after balloon mitral valvuloplasty (BMV) in patients with rheumatic mitral stenosis. RESULTS: Correlations between LA and PAW pressures for a wave, v wave and mean pressure were excellent before BMV (r=0.96, r=0.97 and r=0.99 respectively) and after BMV (r=0.98, r=0.98 and r=1.00 respectively). The fall in mean LA pressure (11.3 +/- 7.9 mm Hg) and in mean PAW pressure (11.1 +/- 7.9 mm Hg) also correlated well. Correlation was good both before and after BMV when subgrouping was done based on average pulmonary vascular resistance and average LA mean pressure in each group. CONCLUSIONS: There is good correlation of PAW pressure with LA pressure even in the presence of pulmonary arterial or venous hypertension. It can replace LA pressure monitoring in any clinical setting.

Adult↗
PubMed2000

Congenital severe aortic stenosis with congestive heart failure in late childhood and adolescence: effect on left ventricular function after balloon valvuloplasty.

Left ventricular (LV) dysfunction with congestive heart failure (CHF) resulting from severe congenital aortic stenosis (AS) is a well-described condition in infancy, but it is rarely found in older children and adolescents. Aortic valve surgery in such cases may be associated with higher rates of morbidity and mortality. Aortic valve balloon dilatation (AVBD) is a viable alternative, but its effect on LV function has not been evaluated. We describe follow-up results of AVBD in 10 cases of severe congenital AS in older children and adolescents with CHF and LV dysfunction. The ages of these patients ranged from 5 to 18 yr (mean +/- SD: 10.8 +/- 4 yr), and nine were males. The follow-up period after AVBD ranged from 3 mo to 7 yr (mean +/- SD: 2.93 +/- 2.1 yr). Success was achieved in all cases, with no immediate complications. After valvuloplasty, the peak-to-peak systolic gradient declined from 74.7 +/- 30.8 to 33.9 +/- 18.2 mm Hg (P < 0.0001). The cardiac index increased slightly but significantly, from 1.9 +/- 0.27 to 2.2 +/- 0.5 L/min/m(2) (P < 0.015). Hemodynamic improvement was also confirmed by a significant decrease in mean pulmonary artery and pulmonary artery wedge pressures from 41.9 +/- 9 to 32.6 +/- 6.6 and from 25.5 +/- 2.9 to 19.3 +/- 3.4 mm Hg, respectively. The echocardiographically derived left ventricular ejection fraction (LVEF) improved from 21.6 +/- 5. 37% to 31 +/- 6.5% within 24 hr after AVBD, and it further improved in all cases on follow-up. Mean LVEF at last follow-up was 59.4 +/- 11.4%. The Doppler instantaneous peak systolic gradient (IPSG) increased from 37.3 +/- 18.8 to 64.8 +/- 30.7 mm Hg at late follow-up. Significant aortic regurgitation (AR) developed in 20% of patients. The Doppler IPSG across the aortic valve was > 60 mm Hg in five cases on follow-up. Two of these patients underwent another AVBD successfully 4 and 16 mo later, respectively. Aortic valve replacement was done in two patients, one for severe restenosis with mild AR 12 mo after AVBD and another for severe re-restenosis with moderate AR 21 mo after a second AVBD. Severe congenital AS can be associated with LV dysfunction and CHF in late childhood and adolescence. AVBD results in good palliation with improvement in LV function on follow-up.

Adolescent↗
PubMed2000

Timing of surgery/catheter intervention in common congenital cardiac defects.

A large load of children with congenital heart disease (CHD) exists in our country. Fortunately facilities for treatment of almost all types of defects are available, although in few centres only. Many children are however, referred late for correction making them either high risk for surgery or inoperable due to development of irreversible pulmonary vascular obstructive disease. Therefore, it is important to recognise the ideal time of intervention in different types of CHD. A child with large atrial septal defect should have its closure by 3 to 4 years of age; on the other hand, a large ventricular septal defect (VSD) producing congestive heart failure needs very early surgery. Infants with small VSD may be medically managed as chances of spontaneous closure are high. Ligation of patent ductus arteriosus should be done at about one year of age if there is no pulmonary arterial hypertension or congestive heart failure. Similarly, coarctation should be dealt with either balloon dilatation or surgery at about one year of age provided the left ventricular function is normal and blood pressure in upper limb is well under control. For tetralogy of Fallot, correction is best done at about 9 months to one year of age. In case the child is symptomatic early, either a palliative shunt is done or total correction is performed if anatomy is suitable. In admixture lesions like transposition of great arteries (TGA), persistent truncus arteriosus or total anomalous pulmonary venous drainage, a very early intervention is needed so as to avoid development of severe hypoxia and early pulmonary vascular obstructive changes. Arterial switch operation is best performed in first two to three weeks of life for TGA with intact ventricular septum cases. Knowledge of natural history of the CHD is essential to plan for optimal timing of surgery or catheter intervention.

Cardiac Catheterization↗
PubMed2000

The need to lower systolic blood pressure.

Systolic hypertension is the most common form of hypertension, especially in individuals aged 60 years or older. Systolic hypertension is a reflection of decreasing compliance of large arteries and is a strong independent risk factor for all cardiovascular diseases. Despite proven benefits of therapy for systolic hypertension, only 25% of patients with this condition are adequately treated to attain target blood pressures. The sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of high blood pressure (JNC VI) recommends the use of diuretics and long-acting dihydropyridine calcium channel blockers as first-line therapy for isolated systolic hypertension. Therapy is also guided by comorbid conditions where certain drugs may have additional benefits. The goal of therapy should be a graded reduction in blood pressure to less than 140/90 mm Hg with lower blood pressure targets in patients with coexistent diabetes or renal failure.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2000

Off-pump redo coronary artery bypass grafting.

BACKGROUND: Conventional redo coronary artery bypass grafting is associated with significant morbidity. The danger of reoperation is mainly in reopening the sternum and in the manipulation of the heart and the old grafts. Therefore, off-pump redo coronary artery bypass grafting with a patient-specific approach in selected cases seems an ideal technique. METHODS: Between October 1995 to September 1999, 50 patients with mean age of 61.8+/-8 years underwent reoperative coronary artery bypass grafting without cardiopulmonary bypass. Isolated left internal mammary artery (LIMA) to left anterior descending artery (LAD) anastomosis was carried out in 25 cases through left anterior minithoracotomy. In 1 patient LIMA was grafted on a previous vein graft to LAD, which was critically stenosed proximally but distal anastomosis was patent. In another case LIMA was grafted to Ramus intermedius branch. Midsternotomy approach was used to carry out LAD and right coronary artery grafting in 21 cases. In 2 patients a posterolateral thoracotomy approach was used to bypass obtuse marginal branches without cardiopulmonary bypass; in these cases proximal anastomosis was performed on the descending aorta. RESULTS: Mortality rate was 4% (2 deaths). Two patients sustained perioperative myocardial infarction. No patient was reexplored for hemorrhage and 38 patients did not require homologous blood transfusion. Sixteen patients underwent check angiogram and all of them were found to have patent redo grafts. Cardiac recovery room stay was 22+/-7 hours and hospital stay 5+/-2 days. CONCLUSIONS: In selected patients, reoperative coronary artery bypass grafting can be performed without cardiopulmonary bypass with a low perioperative morbidity and mortality and satisfactory graft patency.

Coronary Artery Bypass↗
PubMed2000

Total intravenous anesthesia with ketamine for pediatric interventional cardiac procedures.

OBJECTIVE: To evaluate the safety and efficacy of ketamine in pediatric patients undergoing interventional cardiac procedures. DESIGN: A retrospective clinical study. SETTING: A single, tertiary referral center. PARTICIPANTS: Patients (n = 107) undergoing interventional cardiac procedures between July 1996 and July 1998. INTERVENTIONS: Each patient received a bolus of ketamine, 1 mg/kg intravenously, followed by an infusion of 50 to 75 microg/kg/min for the duration of the procedure. MEASUREMENTS AND MAIN RESULTS: Hemodynamic and respiratory parameters were noted. All patients were breathing spontaneously. Average infusion dose of ketamine was 51.40+/-3.54 microg/kg/min (mean +/- standard deviation). Increases in heart rate and mean arterial pressure by more than 20% from baseline values were seen in 10 and 9 patients, respectively. Transient apnea and excessive salivation were seen in two patients each. Excessive movement of extremities was seen in six patients. There were no episodes of unpleasant dreams or hallucinations. There were two deaths (1.9%) related to the interventional procedures. CONCLUSION: The technique described is a simple, safe, and effective method for anesthetizing children in the cardiac catheterization laboratory for interventional procedures.

Adolescent↗
PubMed2000

Immediate and early results of closure of moderate to large patent arterial ducts using the new Amplatzer device.

OBJECTIVES: Our aim was to assess the immediate and short term results of closure of moderate and large patent arterial ducts using the self-expanding and repositionable Amplatzer device. METHOD: We attempted closure in 25 patients (10 Females and 15 males) using the Amplatzer occluder. Their median age was 48 months with a range from 8 months to 26 years and median weight of 14 kg with a range from 4.5 kg to 48 kg. The mean ductal diameter was 4.1 mm (S.D 1.51 mm). A 6F/7F long sheath was used to deliver the device. Follow up was performed with colour- flow mapping of the pulmonary trunk within 24 hours, at 3 months, and 6 months of closure. RESULTS: Of the 25 patients, the device was placed successfully in 23. Concurrent angiography showed immediate closure in 12 patients, while 8 had trivial shunting and 3 had mild shunting. Within 24 hours, Doppler examination revealed complete closure in all but three patients, who had a mild residual shunt. Two attempts were unsuccessful. Both these patients underwent successful surgical ligation. All except one patient were discharged on the next day. Of the 23 patients, 15 (65%) have been followed up for 3 months, while 8 (35%) have completed 6 months of follow-up. Of the three patients initially with mild residual flow, two had completely closed at 3 months The one remaining patient is yet to be seen at the 3 month follow-up. Thus, at 3 months, all patients studies had shown complete closure. CONCLUSION: Antegrade transcatheter closure using the Amplatzer duct occluder is an efficacious treatment for bigger patent arterial ducts. Long-term follow-up is necessary to show sustained benefits and confirm the absence of side effects.

Adolescent↗
PubMed2000

A meta-analysis of Parkinson's disease and exposure to pesticides.

This study examined the association between Parkinson's disease (PD) and exposure to pesticides. A series of meta-analysis of peer-reviewed studies were performed, using 19 studies published between 1989 and 1999. Prior to the meta-analysis, all studies were reviewed and evaluated for heterogeneity and publication bias. Significant heterogeneity among studies was detected and combined odds ratio (OR) was calculated using the random effect model. The majority of the studies reported consistent elevation in the risk of PD with exposure to pesticides. The combined OR studies was 1.94 [95% confidence interval (95% CI) 1.49-2.53] for all the studies, and 2.15 (95% CI 1.14-4.05) for studies performed in United States. Although the risk of PD increased with increased duration of exposure to pesticides, no significant dose-response relation was established, and no specific type of pesticide was identified. Our findings suggest that exposure to pesticides may be a significant risk factor for developing PD.

Case-Control Studies↗
PubMed2000

Long-term results of balloon aortic valvulotomy for congenital aortic stenosis in children and adolescents.

BACKGROUND AND AIM OF THE STUDY: The aim of the study was to report on the long-term results of aortic valve balloon dilatation (AVBD) for congenital valvular aortic stenosis in children and young adults. METHODS: The records of 74 patients (age range: 1-20 years) who underwent AVBD at a single center were analyzed retrospectively. Special attention was paid to factors that might influence long-term outcome. RESULTS: The procedure was successful in 71 patients (96%). The mean (+/- SD) reduction in peak-to-peak systolic gradient (PSG) was 68.7 +/- 13.5%. No patient required immediate surgical intervention. Survival after dilatation was 100% at 12 years. At follow up (mean 5.5 +/- 2.9 years; range: 2-12 years), 20% of patients had restenosis and 21% had significant aortic regurgitation (AR) (grade > or = 3). Reintervention was performed in 14% of patients. Severity of AR and high residual stenosis immediately after AVBD were associated with the late event rates. The actuarial intervention-free rates at five, seven and 12 years were 92.9%, 84.4% and 60%, respectively. CONCLUSION: AVBD is a useful, albeit palliative, procedure for children and young adults with significant congenital valvular aortic stenosis.

Adolescent↗