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Biomedical subjects

K B Shah

Publications and source records attributed to K B Shah.

11 recordsLinked to original sources
PubMed1990

Preparation and evaluation of 99mTc-t-butylisonitrile (99mTc-TBI) for myocardial imaging: a kit for hospital radiopharmacy.

A previous method was modified to obtain [99mTc(TBI)6]+ by reacting Zn(TBI)2Br2 directly with 99mTcO4- in the presence of Sn2+ ions. [Cu(TBI)4]Cl was next used as a source of TBI. On reaction with 99mTcO4- and Sn2+ ions for 3 min at 100 degrees C, [99mTc(TBI)6]+ product of radiochemical purity greater than 90% and yield greater than 70% was obtained. Data of biodistribution in rats (2-2.5% in heart) and biokinetics in rabbits were satisfactory. The kit formulation was found to be stable and also safe for administration.

Animals↗
PubMed1990

Angina and other risk factors in patients with cardiac diseases undergoing noncardiac operations.

Six hundred eighty-eight consecutive patients with cardiac diseases or who were older than 70 yr of age, all of whom were undergoing noncardiac operations, were studied. Twenty-four preoperative risk factors were analyzed for the outcome of perioperative myocardial infarction (PMI) or cardiac death using stepwise logistic regression. Old age, emergency operation, angina, previous myocardial infarction, electrocardiographic signs of ischemia, type of surgical procedure, and hypokalemia were identified as individual factors useful in predicting outcome. Thirty-two patients (4.65%) developed PMI. Seven of these 32 patients (21.9%) and eight more patients without PMI--a total of 15 patients (2.2%)--died a cardiac death. Nonfatal but serious complications occurred in 23% of the patients. Patients undergoing emergency operations and patients with chronic stable angina, previous myocardial infarction, and electrocardiographic signs of ischemia were found to be at increased risk for PMI and cardiac death.

Aged↗
PubMed1990

Reevaluation of perioperative myocardial infarction in patients with prior myocardial infarction undergoing noncardiac operations.

We studied 275 patients with prior myocardial infarctions undergoing noncardiac operations to determine the incidence and outcome of perioperative myocardial reinfarction. Perioperative myocardial reinfarction developed in 13 patients (4.7%) of whom 3 (23%) died of cardiac causes. When time between prior myocardial infarction and the date of anesthesia was analyzed, the incidence of perioperative myocardial reinfarction was 4.3% at 0-3 mo, 0 at 4-6 mo, 5.7% at greater than 6 mo, and 3.3% at an indeterminate exact interval. None of the variables analyzed showed any significant correlation with the rate of reinfarction. The urgency of operation and aortic or vascular procedures were the only variables that approached, but failed to achieve, statistical significance.

Adult↗
PubMed1989

Cardiac transplantation: a prospective comparison of ketamine and sufentanil for anesthetic induction.

The hemodynamic effects of ketamine, 1.5 mg/kg, or sufentanil, 3.4 +/- 0.3 micrograms/kg, were studied prospectively for the anesthetic induction of 20 patients with cardiomyopathies undergoing cardiac transplantation. Plasma epinephrine (EPI), norepinephrine (NE), and sufentanil levels were also obtained. Measurements were taken at various times before induction and following intubation. Following ketamine, progressive increases (P less than 0.05) in mean arterial pressure (28%, MAP), mean pulmonary artery pressure (56%, PAP), central venous pressure (109%, CVP), and pulmonary capillary wedge pressure (84%, PCWP) occurred over time, whereas the cardiac index (CI), stroke volume index (SVI), and stroke work index (SWI) remained unchanged or decreased. The use of sufentanil was associated with no significant changes in MAP, PAP, CVP, PCWP, CI, SVI, or SWI. The heart rate (HR) did not significantly change in either group. Plasma NE significantly increased (31%) in the ketamine group, peaking at 10 minutes; whereas EPI levels did not significantly change in either group. Plasma sufentanil did not reflect the microgram/kg or microgram/BSA administered dose, suggesting individualized distribution kinetics. Since perioperative morbidity and mortality did not differ between groups, both ketamine and sufentanil are acceptable drugs for the anesthetic induction for cardiac transplantation. However, the dissimilar hemodynamic effects caused by ketamine and sufentanil suggest that this conclusion may not be applicable to the patient with a cardiomyopathy undergoing noncardiac surgery.

Adolescent↗
PubMed1987

Multiple tamping effects on drug dissolution from capsules filled on a dosing-disk type automatic capsule filling machine.

The effects of number of tamps and tamping force on drug dissolution from capsules filled on an instrumented dosing-disk automatic capsule filling machine (Hofliger-Karg) were studied using hydrochlorothiazide as a model, low dose, poorly soluble drug. Generally, there was a trend toward slower dissolution rate with increasing numbers of tamps, the effect being most marked when insoluble dicalcium phosphate dihydrate was the filler. Higher compression forces improved drug release when anhydrous lactose was the filler, but adversely affected the dicalcium phosphate-based capsules. Inclusion of 4% croscarmellose sodium disintegrant tended to nullify the effects of number of tamps or tamping force with both fillers; however, the disintegrant also markedly enhanced drug dissolution from the dicalcium phosphate-based formulation. Hydrochlorothiazide dissolution from the latter formulation without disintegrant appeared to follow a "diffusion from insoluble matrix" model regardless of number of tamps or their intensity. Mercury intrusion pore size distribution data for some plugs suggested that for tamps of equal force (100 or 200 N), further powder consolidation after two tamps does not occur.

Capsules↗
PubMed1986

An investigation of some factors influencing plug formation and fill weight in a dosing disk-type automatic capsule-filling machine.

The progressive formation of plugs resulting from successive tamps in a dosing disk-type automatic capsule-filling machine was investigated for three fillers: anhydrous lactose, dicalcium phosphate, and microcrystalline cellulose. An evaluation of seven compaction parameters revealed that all tamping stations and all piston positions within a station, with the exception of station #1, contribute equally to plug formation. Model calculations suggesting that fill weight could be achieved in only three tamps were supported by direct experimental observation. The effective available fill volume was shown to be greater than the nominal volume of the dosing disk cavity. This was verified by using a modified scrape-off at station #5, which eliminated the powder head over the disk at that station. Here, increases in tamping force resulted in harder plugs, as measured with an improved plug mechanical strength tester, with fill weights remaining unchanged. However, plug segments did not increase in mechanical strength when additional segments were compressed over them using the same force. For one excipient (microcrystalline cellulose), the fill weights and the mechanical strengths of systems containing 0, 0.10, 0.25, and 0.50% magnesium stearate were measured. The 0.10% level was found to be optimum in that it resulted in maximum plug mechanical strengths and fill weights, regardless of the number of tamps used and/or their intensity.

Capsules↗
PubMed1984

A review of pulmonary artery catheterization in 6,245 patients.

From July 1977 to December 1982, 6,245 patients requiring cardiac and noncardiac operations had pulmonary artery (PA) catheterizations for perioperative monitoring. Their ages ranged from 4 to 94 years. PA catheters were inserted through the external or internal jugular vein in 6,146 patients, while arm veins were used in 99 patients. Complications included persistent PVCs requiring therapy in 193 (3.1%), right bundle branch blocks in three (0.048%), left bundle branch and complete heart block each in one patient (0.016%), intrapulmonary hemorrhage in four (0.064%), minor pulmonary infarcts in four (0.064%), perforation of right ventricle in one (0.016%), and death from uncontrollable pulmonary hemorrhage in one patient (0.016%). This investigation reveals a low incidence of morbidity associated with PA catheterization.

Adolescent↗
PubMed1983

Solid-phase radioimmunoassay for human placental lactogen in serum.

We report a solid-phase radioimmunoassay for human placental lactogen, in which antibody-coated polystyrene tubes and polyurethane sponges are used. Incubation time and temperature, ionic strength of buffer, and nonspecific adsorption have been evaluated for optimum conditions required for routine clinical assays. The validity of the assay technique has been ascertained by its specificity, reproducibility, and recovery. The sensitivity of this method is 0.4 ng of placental lactogen per assay tube.

Female↗