Lethal complication of a rare cardiac tumor.

Cardiac tumors, especially malignant ones, are rare and diagnosis is challenging since symptoms manifest late and are often non-specific. Achieving a histological diagnosis prior to resection is also difficult because biopsies often fail to yield conclusive results. Due to the low frequency, no standard treatment protocol exists and the prognosis is poor. We present a case of a cardiac sarcoma, which was found during an autopsy performed with regard to medical malpractice, because the patient died due to a medical intervention. To report cases like this is important to gain more knowledge about possible complications regarding rare diseases.

Resting energy expenditure in the obese: a cross-validation and comparison of prediction equations.

OBJECTIVE: To examine the accuracy and precision of 12 equations or tables for predicting resting metabolic rate (RMR) in obese persons. DESIGN: Observational (correlational) study. SETTING: Obesity Research Center, St Luke's/Roosevelt Hospital, New York, NY. SUBJECTS/SAMPLES: One hundred twenty-six (73 women, 53 men) healthy, obese subjects recruited through the Obesity Research Center's Weight Control Unit. MEASURES: RMR by indirect calorimetry. Weight and height were measured to the nearest 0.1 kg and to the nearest 1 cm. STATISTICAL ANALYSES PERFORMED: Bivariate regression of predicted RMR on measured RMR; paired t tests for the difference between means of predicted RMR and measured RMR. RESULTS: Of the 12 prediction equations, 6 had intercepts or slopes that were significantly different from 0 and 1, respectively. With two exceptions, the equations accounted for between 56% and 63% of the variance in measured RMR. The Robertson and Reid (1952) equation and the Fleisch (1951) equation performed best with our obese sample. APPLICATIONS/CONCLUSIONS: The Robertson and Reid (1952) and the Fleisch (1951) equations are recommended for clinical use with obese patients.

Influence of benzalkonium chloride on the dissolution rate behavior of several solid-phase preparations of cholesterol in bile acid solutions.

Cholesterol dissolution rate accelerators, such as benzalkonium chloride, function by reducing the interfacial barrier that exists between the negatively-charged bile acid micelle and the negatively-charged cholesterol surface. It has been proposed that this reaction is accomplished by the binding of the positively-charged accelerator to the negatively-charged micelle. An earlier report showed that different solid preparations of cholesterol give different dissolution rates under the same conditions and these differences can be primarily accounted for by variations in the interfacial transport constant (P). By using the rotating disk dissolution apparatus and the Levich theory it has been possible to study the dissolution behavior of different cholesterol solid phases as a function of the benzalkonium chloride concentration. It was shown that the ratios of P values for the different phases are relatively constant over the range of the accelerator concentrations. This suggests that the accelerators act primarily on the micelle to enhance dissolution rate.

Dissolution rate behavior of solid cholesterol preparations in bile acid solutions.

Recent work in these laboratories showed that different preparations of cholesterol monohydrate and anhydrous cholesterol had different dissolution rates under the same conditions. A method was developed by which both the thermodynamic contribution (Cs) and the interfacial kinetic contribution (P) to dissolution could be determined from experimental data. The rotating-disk dissolution method was used with the Levich theory to assess the data. Dissolution rates were determined in solutions partially saturated with cholesterol. Dynamic solubilities were determined by plotting dissolution rates (J/A) versus bulk concentration (Cb) and extrapolating to zero J/A. By using a best-fit analysis, it was possible to determine solubility as well as the interfacial transport constant independently. When this method was used to study differences in dissolution behavior of different solid preparations of cholesterol the differences could be accounted for primarily by variations in the interfacial transport constant rather than by solubility variations.

Variability in dissolution rates of cholesterol pellets in bile acid solutions.

Large variations in dissolution rate behavior of cholesterol monohydrate pellets may result from small changes in experimental procedures. For example, when cholesterol monohydrate pellets were stored overnight prior to a dissolution run, the initial dissolution rates varied by more than a factor of 2. It is well known that cholesterol monohydrate is converted to anhydrous cholesterol; cholesterol may be unstable toward light. heat, and other radiation in the presence of air, leading to its decomposition. To determine the cause of the variable dissolution rates, experiments were conducted with pellets "aged" under various conditions. The data shown that the probable cause of the variations is the pellet surface conversion of the monohydrate to anhydrous cholesterol, which may take place during pellet storage. The combined effects of temperature and humidity seem to be important. A uniform experimental procedure is needed if investigators hope to reproduce results within their own laboratories as well as reproduce the findings of others.

Dissolution rates of model gallstones in human and animal biles and importance of interfacial resistance.

Cholesterol monohydrate dissolution kinetics in human gallbladder bile were studied to determine the magnitudes of the in vitro dissolution rates, the rate resistances in human gallbladder bile, and the extent that the interfacial resistance is the rate-determining factor. Dissolution rate studies also were conducted using human duodenal bile and animal bile for comparison. The dissolution rate resistance, R, ranged from 10(4) sec/cm for chicken bile to 10(4)-10(6) sec/cm for human bile. Interfacial resistance was the rate-determining factor for essentially all results. Where chemical composition data were obtained, the R values for the human bile samples were consistent with predictions made from the simulated bile studies. In two human gallbladder specimens having low bile acid-lecithin molar ratios (i.e., 2.9 and 2.3), very high R values of 1.9 X 10(5) and 4.1 X 10(5) sec/cm were found. These values were in good agreement with the findings in the simulated bile studies and suggest that stone dissolution in patients with low bile acid-lecithin ratios may proceed very slowly, even when the bile is highly undersaturated with respect to cholesterol.