A case of purulent pneumococcal pericarditis

Background

Purulent bacterial pericarditis is a rare and potentially fatal disease. The course may be fulminant, and the presentation may pose a diagnostic challenge.

An overview of existing mesothelioma registries worldwide,and the need for a US Registry

The association between asbestos exposure, mainly in occupational settings, and malignant mesothelioma has been well established; this has prompted several countries to establish mesothelioma epidemiologic surveillance programs often at the request of national agencies. This review compares currently existing mesothelioma registries worldwide to develop a concept model for a US real-time case capture mesothelioma registry. Five countries were identified with a mesothelioma specific registry, including Italy, France, UK, Australia, and South Korea. All, except the UK, used interviews to collect exposure data. Linkage with the national death index was available or was in future plans for all registries. The registries have limited information on treatment, quality of life, and other patient-centered outcomes such as symptoms and pain management. To thoroughly collect exposure data, “real-time” enrollment is preferable; to maximize the capture of mesothelioma cases, optimal coverage, and a simplified consent process are needed.     

The precision of positron emission tomography: theory and measurement

The limits of quantitation with positron emission tomography (PET) are examined with respect to the noise propagation resulting from radioactive decay and other sources of random error. Theoretical methods for evaluating the statistical error have been devised but seldom applied to experimental data obtained on human subjects. This paper extends the analysis in several ways: (1) A Monte Carlo method is described for tracking the propagation of statistical error through the analysis of in vivo measurements; (2) Experimental data, obtained in phantoms, validating the Monte Carlo method and other methods are presented; (3) A difference in activation paradigm, performed on regional CBF (rCBF) data from five human subjects, was analyzed on 1.6-cm diameter regions of interest to determine the mean fractional statistical error in PET tissue concentration and in rCBF before and after stereotactic transformation; and (4) A linear statistical model and calculations of the various statistical errors were used to estimate the magnitude of the subject-specific fluctuations under various conditions. In this specific example, the root mean squared (RMS) noise in flow measurements was about three times higher than the RMS noise in the concentration measurements. In addition, the total random error was almost equally partitioned between statistical error and random fluctuations due to all other sources.     

Pharmacokinetics of intravenous bepridil in patients with coronary disease

The pharmacokinetics of intravenous bepridil (1-[2-(N-benzylanilino)-1-(isobutoxymethyl)ethyl]pyrrolidine ) were studied in 16 patients undergoing cardiac catheterization for evaluation of coronary disease, all with normal base-line hemodynamic and renal functions. Ten patients received 3 mg/kg and six patients received 4 mg/kg of bepridil infused over a period of 30 min. Plasma bepridil concentrations were measured by HPLC and analyzed by model-dependent and model-independent methods. The mean (+/- SD) maximum plasma bepridil concentrations at the end of the infusion were 2047 +/- 820 ng/mL (3 mg/kg) and 2478 +/- 1426 ng/mL (4 mg/kg). Postinfusion bepridil concentrations were best described by a two-compartment open model. The model-dependent harmonic mean distribution and elimination half-lives were 1.7 h (range: 1.1-2.2 h) and 19.7 h (range: 8.0-61.9 h), respectively. The harmonic mean elimination half-life from model-independent analysis was 14.9 h (range: 7.4-64.0 h). The arithmetic means of other model-independent kinetic parameters were systemic clearance, 0.524 +/- 0.215 L X kg-1 X h-1; Vd, 15.3 +/- 10.9 L/kg; and Vdss, 10.1 +/- 6.0 L/kg. Model-dependent and model-independent estimates of half-life and clearance agreed reasonably well. Bepridil was well tolerated, effecting little or no change in central hemodynamics or EKG intervals. The extensive distribution and relatively slow clearance of bepridil account for its long elimination half-life. Intravenous bepridil appears to be a safe calcium (II) antagonist that is suitable for once-a-day dosing.     

Cardiac conduction abnormalities and atrial arrhythmias associated with salicylate toxicity

Cardiac side effects from aspirin are uncommon; however, severe acid-base imbalance, pulmonary edema, ventricular ectopic activity and cardiopulmonary arrest have been reported in patients with toxic serum salicylate concentrations. We saw a patient with salicylate toxicity who developed a variety of sinus and atrioventricular nodal conduction disturbances and atrial arrhythmias with a relatively low toxic serum salicylate concentration. The cardiac rhythm returned to normal as the serum salicylate concentration decreased, and results of subsequent electrophysiologic testing and Holter monitoring were normal. A low serum albumin level may have resulted in altered salicylate binding in this patient, thereby increasing the availability of unbound (active) drug for toxic effects.     

Four cases of obstructive sleep apnea associated with treatment-resistant mania

The authors describe four cases in which obstructive sleep apnea complicated the course and treatment of mania. An association between weight gain, obstructive sleep apnea, and lithium treatment is also illustrated.     

Measurement of end-capillary PO2 with positron emission tomography

The analysis of positron emission tomography measurements of oxygen metabolism has been extended to provide a quantitative estimate of end-capillary PO2. The principle of this extension rests on the idea that the oxygen extraction fraction can be used to calculate the end-capillary oxygen saturation of the blood. The relation between oxygen saturation and PO2 is obtained through the oxygen dissociation curve. Our studies show that in addition to the local oxygen extraction fraction, arterial PO2 and pH values are needed in the calculation, whereas fairly large variations in factors such as PCO2, hematocrit, hemoglobin, and plasma protein levels have little or no effect. Rough estimates of end-capillary PO2 can be made using standard O2 dissociation nomograms. Blood gas and acid-base properties of blood have been known for decades, making it possible to account accurately for individual differences that may be encountered when studying patients. Measurements in nine normal subjects yielded a mean end-capillary PO2 value of 31.2 mm Hg. The ability to make a quantitative visualization of altered patterns of end-capillary PO2 provides an additional dimension to the investigation of stroke disease and tumor metabolism.     

Nonbronchoscopic approach to bronchoalveolar lavage in children with artificial airways.

Bronchoalveolar lavage (BAL) performed with a fiberoptic bronchoscope (FOB) is a useful method for sampling alveolar contents. Since the smallest FOB with a channel has a diameter of 3.6 mm, BAL is difficult to accomplish through artificial airways (AA) less than 5.0 mm I.D. We used a 4F balloon wedge pressure catheter to perform BAL through small AA. Supplemental O2 or ventilatory support was delivered via an adaptor through which the catheter was introduced. After it was passed distal to the AA, the balloon was inflated with normal saline (NS) to a predetermined volume, and advanced until resistance was felt. The balloon was deflated, advanced slightly, and then reinflated to achieve airway occlusion. Five aliquots of 0.75 mL/kg of NS were used for BAL. The procedure was performed in 20 children from 1 month (950 g) to 6 1/2 years of age (median, 9 months). All specimens contained abundant alveolar macrophages, indicating good recovery of alveolar contents. Clinically significant information was obtained in 17 (85%) cases, and no patient required an open lung biopsy. In conclusion, nonbronchoscopic bronchoalveolar lavage is a valuable method for obtaining alveolar contents in children with small AA that preclude the use of an FOB, and it obviates the need for open lung biopsy in many patients. This technique could be used as a research tool for measuring constituents of alveolar contents in infants and small animals.     

Ethnicity, pressor reactivity, and children's blood pressure. Five years of observations.

During the 5 years of this investigation, resting blood pressure and pressor reactivity were measured in 292 white children and 46 black children in 1987, 1988, 1989, and 1991. In 1987, all children were in the third grade; in 1991, the children were in the seventh grade. Reactivity was assessed with a standardized psychological stressor, a television video game. Children displayed significant stability of absolute blood pressure and heart rate reactivity between grades 3 and 7. At all examinations, black children demonstrated blood pressure reactivity that was significantly greater in magnitude (both absolute level and change from resting measurements) than that of white children. Black children exhibited significantly greater heart rate reactivity only when defined as change from the resting measurements; absolute levels of heart rate reactivity were comparable for blacks and whites. For black children, blood pressure reactivity in 1987 was the strongest predictor of resting blood pressure (both systolic and diastolic) in 1991. Among white children, resting blood pressure was the strongest predictor of future resting blood pressure. Further research is needed to determine if ethnic differences in children's pressor reactivity are associated with ethnic differences in the prevalence of hypertension.