An assessment of factors which influence the effectiveness of the modified in vivo technetium-99m-erythrocyte labeling technique in clinical use.

This study assessed factors which may contribute to suboptimal image quality when the modified in vivo erythrocyte labeling technique is used with standard clinical 99mTc activities. For each assessment duplicate or triplicate blood specimens were withdrawn from > or = 10 patients, into syringes containing 700-900 MBq 99mTc as pertechnetate. After incubation the percent of 99mTc which was not bound to erythrocytes at blood re-injection time (%Unbound 99mTc), was measured and compared when one of four factors was varied. The most significant results, in descending order of measured effect were: [table: see text] Our data suggest that the requirements for optimal erythrocyte labeling with standard clinical 99mTc activities are: (A) Erythrocyte tinning time between 10 and 30 min; (B) blood volume > or = 3 ml; (C) blood incubation time > or = 20 min; and (D) Generator ingrowth time < or = 24 hr.     

Complications Related to Dapsone Use for Pneumocystis Jirovecii Pneumonia Prophylaxis in Solid Organ Transplant Recipients

Dapsone, used for prevention of Pneumocystis jirovecii infections, has been reported to cause hemolytic anemia and methemoglobinemia; its tolerability in solid organ transplant recipients is not well described. We investigated dapsone-related adverse events in patients undergoing solid organ transplantation from 1999 to 2004. Transplant providers identified patients for the investigators who then reviewed the patients' hospital and outpatient records. Sixteen solid organ transplant recipients fit case definitions for dapsone-related hemolytic anemia (n = 11) or methemoglobinemia (n = 5). Median time from event to dapsone discontinuation was 15 days; all patients improved after drug discontinuation. G6PD enzyme activity was normal in all patients whose test results were available. Dapsone may be associated with hemolytic anemia or methemoglobinemia, even with normal G6PD levels. These events are often not promptly recognized, and drug discontinuation is delayed. Dapsone-related hemolytic anemia or methemoglobinemia should be considered in solid organ transplant recipients with unexplained anemia or hypoxia.     

Preliminary assessment of fluorine-18 fluorodeoxyglucose positron mission tomography in patients with bladder cancer

The purpose of this study was to assess the feasibility of imaging of bladder cancer with fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) scanning. We studied 12 patients with histologically proven bladder cancer who had undergone surgical procedures and/or radiotherapy. Retrograde irrigation of the urinary bladder with 1000–3710 ml saline was performed during nine of the studies. Dynamic and static PET images were obtained, and standardized uptake value images were reconstructed. FDG-PET scanning was true-positive in eight patients (66.7%), but false-negative in four (33.3%). Of 20 organs with tumor mass lesions confirmed pathologically or clinically, 16 (80%) were detected by FDG-PET scanning. FDG-PET scanning detected all of 17 distant metastatic lesions and two of three proven regional lymph node metastases. FDG-PET was also capable of differentiating viable recurrent bladder cancer from radiation-induced alterations in two patients. In conclusion, these preliminary data indicate the feasibility of FDG-PET imaging in patients with bladder cancer, although a major remaining pitfall is intense FDG accumulation in the urine. Present address: Department of Radiology, National Defense Medical College, 3-2 Namiki, Tokorozawa 359, Japan     

Decomposing Area of Residence Differences in Multiple Regression Studies: The Relative Contributions of Independent Variables and Model Coefficients

When rural/urban differences are found in health status or health care use, it is often desirable to identify those factors (such as age, social structure, income, etc.) that influence such differences. To this end, researchers often test rural/urban differences in age, social structure, income, etc., for statistical significance. Also, researchers commonly perform multivariate analyses (such as multiple regressions) to examine rural-urban differences in the influence of various independent variables on the dependent variable of interest. Frequently, researchers discover: (1) statistically significant rural/urban differences in the independent variables (such as age, social structure, income, etc.) and (2) statistically significant rural/urban differences in the effects of these independent variables (i.e., statistically significant rural/urban differences in regression coefficients). The analysis typically stops here, without addressing the relative contributions of (1) and (2) to the rural/urban differences in the dependent variable. This paper argues that the relative contributions of (1) and (2) have important implications for the way policy-makers address rural health problems. This paper presents a method for assessing the relative contributions of differences in the independent variables and differences in regression coefficients to observed differences in the dependent variable, and illustrates the application of the method by analyzing rural/urban differences in the risk of institutionalization.     

Rabbit Liver Class III Alcohol Dehydrogenase: A Cathodic Isoform with Formaldehyde Dehydrogenase Activity

Electrophoresis of rabbit liver homogenate on starch gel followed by activity staining revealed multiple forms of alcohol dehydrogenase (ADH) which, based on their electrophoretic mobilities, had been tentatively labeled as class "I," class "II," and dass "III" ADHs. The class II enzyme has now been purified to homogeneity by ion exchange and affinity chromatography and, except for an isoelectric point of 7.7, close: resembles human class III ADH. It is a homodimer of molecular weight near 80,000 with a similar amino acid composition and comparable kinetic parameter for the oxidation of primary alcohols. Like the rat, human, and Escherichia coli class III ADHs, the rabbit enzyme is a glutathione-dependent formaldehyde dehydrogenase, and catalyzes the oxidation of S-hydroxymethylglutathione and the hemithiolacetal of 8-thiooctenolc acid. Ethanol up to 3 M does not saturate the enzyme, whereas longer chain primary alcohols exhibit Michaelis-Menten kinetics. Key Words: XX-ADH, FDH.     

Trauma: a systematic approach to management

Initial care of the trauma victim begins at the scene of the accident, where the "load and go" principle is applied. A systematic approach to management of the trauma victim improves patient outcome. After insertion of an airway and stabilization of the spine, hemorrhage is treated and volume is replaced. At this point, invasive techniques, such as chest tube insertion, peritoneal lavage and pericardiocentesis, may be therapeutic as well as diagnostic.