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Biomedical subjects

H Patel

Publications and source records attributed to H Patel.

245 records · Page 14Linked to original sources
PubMedDate not supplied

Factors affecting the exercise capacity of pediatric patients with aortic regurgitation.

Although exercise testing is commonly employed to identify adult aortic regurgitation (AR) patients with early left ventricular (LV) dysfunction, the role and value of exercise testing in the management of pediatric AR patients have not been established. The purposes of this study were to evaluate the cardiorespiratory response to exercise of pediatric patients with chronic AR, examine the relation between exercise function and baseline echocardiographic measurements, and identify factors related to diminished exercise capacity (EC). The study group consisted of 26 patients aged 8 to 21 years (mean 14.4 +/- 3.7) with moderate or severe AR referred for exercise physiology testing. All patients underwent a baseline echocardiographic study and a symptom-limited, progressive cycle ergometer exercise test. LV diastolic dimension averaged 120 +/- 12% predicted, systolic dimension 112 +/- 20% predicted, shortening fraction 0.41 +/- 0.07, end-systolic wall stress 65 +/- 23 g/cm(2), and regurgitant fraction 38 +/- 16%. The average EC was 88 +/- 28% (56-143) predicted. No statistically significant correlation was found between EC and any of the echocardiographic parameters studied. Nine patients had EC < 75% predicted. These individuals did not differ from patients with higher EC with regard to any of the echocardiographic parameters or with regard to peak heart rate, blood pressure, respiratory exchange ratio, and incidence of ectopy or ST depression. However, the oxygen pulse at peak exercise (an index proportional to forward stroke volume at peak exercise) was significantly depressed among patients with EC < 75% predicted (77 +/- 6 vs. 106 +/- 16% predicted, p <. 0001). In conclusion, most pediatric patients with moderate or severe AR compensate well for their valve disease, maintain normal forward stroke volume during exercise, and have normal EC. However, a subset of AR patients have diminished EC secondary to an inability to augment forward stroke volume appropriately. These patients cannot be identified on the basis of resting echocardiographic studies. Timely identification of these patients, through formal exercise physiology testing, may have important clinical implications.

Adolescent↗
PubMedDate not supplied

Effects of dextran on hippocampal brain slice water, extracellular space, calcium kinetics and histology.

Hippocampal brain slices are valuable models for studying brain function but are compromised by several artifacts, including significant water gain and histologic injury, which occur under certain incubation conditions. Addition of colloid to Krebs-Ringer buffer (K-R) has been shown to eliminate water gain but has not achieved widespread acceptance. We confirm prior observations that dextran and PEG lessen the increase in slice mass during incubation in a dose-dependent manner with no water gain occurring at 4% concentrations. However, we also observe that addition of colloid to standard K-R induces severe neuronal pyknosis. Fortunately, the pyknosis can be eliminated by reduction in buffer osmolarity through adjustment of NaCl, producing markedly improved slice histology in dextran buffer, especially in the CA3 and CA4 regions of the hippocampus which are severely injured when incubated submerged in K-R at 37 degrees C. Extracellular space markers are not affected by either colloid. The volume of distribution for 45Ca is much larger in dextran buffers than in K-R and variability of 45Ca kinetics is also reduced. In the presence of dextran, hypoxia induces significant slice water gain, a relatively selective histologic injury and an alteration of tissue Ca2+ kinetics. Use of dextran buffers may eliminate many troubling brain slice artifacts.

Animals↗
PubMedDate not supplied

Animal models.

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Animals↗
PubMedDate not supplied

Neurologic complications of pediatric liver transplantation.

The neurologic complications of 24 children, ages 5 months to 18 years, following orthotopic liver transplantation at the Indiana University hospitals are reported. Biliary atresia (14 patients) was the most common cause for orthotopic liver transplantation. Three children died. Seventeen children (70%) had no neurologic deficit on follow-up 6 months or longer after transplantation. Eleven children (46%), including 4 of 16 patients (25%) who had received OKT3, had neurologic complications. Seven children (29%) had new-onset seizures; 4 of these patients had status epilepticus. Two children had intracranial hemorrhage. Seizures occurred later in children than in adults following orthotopic liver transplantation and were not associated with poor prognosis. Longer term follow-up is indicated to assess subtle, cognitive deficits following liver transplantation in children.

Adolescent↗
PubMedDate not supplied

A novel index for the description of molecular linearity.

To investigate the description of molecular shape, a heterogeneous data set of 200 compounds was designed. The compounds included many disparate molecular shapes, and a total of 64 descriptors was calculated including topological indices, surface areas, molecular volumes, measures of molecular dimensions, and ratios of moments of inertia. Cluster analysis on the variables indicated that there are four major categories of steric descriptors, those for molecular bulk, dimensions, and two clusters representing varying aspects of shape. To describe molecular shape more efficiently, a novel linearity index based upon ratios of moments of inertia and the molecular weight is proposed.

Journal Article↗
PubMedDate not supplied

Evaluation of a unique oral contraceptive in the treatment of premenstrual dysphoric disorder.

Premenstrual dysphoric disorder (PMDD) is a severe form of premenstrual syndrome (PMS). This is the first trial of a unique oral contraceptive containing a combination of drospirenone (DRSP, 3 mg) and ethinyl estradiol (EE, 30 microg) for the treatment of PMDD. DRSP is a spironolactone-like progestin with antiandrogenic and antimineralocorticoid activity. Spironolactone has been shown to be beneficial in PMS, whereas oral contraceptives have shown conflicting results. In this double-blind, placebo-controlled trial, 82 women with PMDD (Diagnostic and Statistical Manual of Mental Disorders, 4th ed. [DSM IV]) were randomized to receive DRSP/EE or placebo for three treatment cycles. The primary end point was change from baseline in luteal phase symptom scores as assessed on the Calendar of Premenstrual Experiences (COPE) scale. Patients treated with DRSP/EE showed a numerically greater change from baseline compared with those treated with placebo on each of the 22 COPE items and each of the 4 symptom factors. Between-group differences in symptom improvement reached statistical significance in factor 3 only (appetite, acne, and food cravings, p = 0.027). The secondary end points, Beck Depression Inventory (BDI) and Profile of Mood States (PMS), were consistent with the primary end point in that patients treated with the oral contraceptive showed a numerically greater improvement from baseline compared with those treated with placebo. The results of this study show a consistent trend in the reduction of symptoms that suggested a beneficial effect of DRSP/EE for the treatment of PMDD, despite limitations of the study design.

Adaptation, Psychological↗
PubMedDate not supplied

MRI of Guillain-Barré syndrome.

We describe the results of MRI of the spine in a case of Guillain-Barré syndrome. The main finding was abnormal enhancement of the nerve roots in the region of the conus medullaris and cauda equina.

Cauda Equina↗
PubMedDate not supplied

An assessment of the efficacy of atorvastatin in treating patients with dyslipidaemia to target LDL-cholesterol goals: the atorvastatin matrix study.

A total of 531 patients from 57 hospital centres across the UK, who had previously been treated with lipid-lowering agents in combination or alone, in whom the degree of cholesterol reduction was insufficient to achieve European Atherosclerosis Society target levels, were treated with atorvastatin over a 12-week period. The dose of atorvastatin (10, 20 or 80 mg/day) was determined by assignment of risk based on entry level cholesterol levels and the presence of other established CHD risk factors. Atorvastatin was successful in achieving target LDL-cholesterol levels in 86% of mild risk patients, 88% of moderate risk patients and 52% of high risk patients. Compliance with atorvastatin was 96% and treatment was well tolerated. This study demonstrates that atorvastatin is effective in achieving target lipid levels in a large proportion of patients and that the dose required can be predicted by an assessment of the patient's risk profile.

Adult↗
PubMedDate not supplied

Evaluation of intravenous flavopiridol formulations.

Flavopiridol is currently under consideration as a parenteral treatment of breast tumors. The solubility of this poorly water-soluble compound can be increased by a number of methods. However, because of its low water solubility, precipitation of the solubilized drug upon injection can be a problem. The potential of several flavopiridol formulations to precipitate is evaluated using a static serial dilution technique. It is shown that formulations containing up to 10 mg/mL of flavopiridol which produce negligible precipitation on dilution can be developed.

Antineoplastic Agents↗