Serum ALT levels. Effect of sex, race, and obesity on unit rejection rate

Alanine aminotransferase (ALT) measurements in blood donors has been advocated as a surrogate test for non-A, non-B hepatitis. Use of the recommended single cutoff value for all donors resulted in disqualifying four times as many males as females in a group of 4712 donors. Separate cutoff values were calculated for male and female donors. The use of these separate cutoff values resulted in disqualifying equal numbers of males and females.     

Candida infections of medical devices

The number of indwelling medical devices is escalating, and an increasing proportion of device-related infections are being caused by Candida spp. Candida spp. produce biofilms on synthetic materials, which facilitates adhesion of the organisms to devices and renders them relatively refractory to medical therapy. Management of device-related Candida infections can be challenging. Removal of the infected device is generally needed to establish cure of Candida infections of medical devices. However, since the pathogenesis of Candida bloodstream infection is complicated, more studies are necessary to determine the role of catheter exchange in patients with both gastrointestinal tract mucositis and indwelling catheters. The medical and economic impact of these infections is enormous.     

Prognostic Impact of Angiogenesis in Nonmuscle Invasive Bladder Cancer as Defined by Microvessel Density after Immunohistochemical Staining for CD34

Bladder cancer is the second most common malignancy of the urogenital region. The majority of bladder cancer deaths occur as a consequence of metastatic disease. Microvessel density (MVD), a surrogate marker for angiogenesis, has been shown to be predictive of progression and poor prognosis. The aim of this study was to evaluate the predictive value and prognostic significance of angiogenesis in human non muscle invasive bladder cancer (NMIBC) treated by BCG immunotherapy. The frozen sections of 28 non muscle invasive bladder cancer specimens were stained with CD34 antibody to label the vascular endothelium using the standard streptavidin-biotin immunoperoxidase method. Angiogenic activity was measured using microvessel count determined by the expression of vascular markers CD34.The prognostic significance of tumor stage, grade, loci number, tumor size, age and CD34 expression in determining the risk for recurrence was studied with both univariate and multivariate methods of analysis. According to univariate analysis of the prognostic significance for tumor stage, grade, tumor size, loci number, age and CD34 expression, in patients with NMIBC, the pT1 stage and high grade seem to be associated in a statistically significant manner with higher risk for recurrence (P=0.004, P=0.004, respectively). In the other hand, multivariate Cox regression's analysis showed that microvessel density and multiplicity were independent predictor of recurrence after BCG immunotherapy (p=0.016, p=0.032, respectively). This study provides strong evidence that CD34 MVD is associated with recurrence after BCG immunotherapy. Independent studies, however, will be required on larger cohort to validate these findings.     

Incubation Alone Is Adequate as a Culturing Technique for Cardiac Rhythm Management Devices

There exist no standardized methods for culturing cardiac rhythm management devices. To identify the most optimal culturing method, we compared various techniques that comprise vortex, sonication, and incubation or combinations thereof. Incubation alone yielded bacterial colony counts similar to those of other culturing combinations and is the least labor-intensive.Permanent pacemakers (PPM) and implantable cardioverter-defibrillators (ICD) are being utilized increasingly because of an aging population (5, 9). About 180,284 PPM and 57,436 ICD were inserted into cardiac patients in the United States in 2003 (10), and worldwide there are 3 million functioning PPM and 180,000 indwelling ICD (2). Infection is the most common serious complication of PPM and ICD, which are collectively referred to as cardiac rhythm management devices (CRMD). The rates of infection of CRMD range from 0.13% to 19.9% (3, 7) with an average rate of 4% (4). Staphylococcus epidermidis and Staphylococcus aureus collectively account for 70 to 95% of CRMD infections (1, 6). A National Hospital Discharge Survey from 1996 to 2003 indicated that along with the rising use of cardiac medical devices, there has been a disproportional increase in the number of infections of such devices (10). The average cost of combined medical-surgical treatment of an infected CRMD was estimated at $35,000 (4).There are no standardized methods for culturing explanted cardiac generators and leads of the CRMD. Although it has been demonstrated that sonication increases the yield of bacterial cultures from prosthetic joints (8), the utility of this diagnostic approach for CRMD has not been published. To identify the most optimal culturing method, we compared the bacterial yield of various techniques that comprise incubation, vortex, sonication and combinations thereof.     

Seasonal variations in urinary risk factors among patients with nephrolithiasis

Twenty-four hour urine specimens from 5,677 stone-forming patients throughout the United States were analyzed for seasonal variations in urinary risk factors for nephrolithiasis. Determinations were performed for urine volume, pH, calcium, oxalate, phosphorus, sodium, magnesium, citrate, sulfate, uric acid, and the relative supersaturation (RS) of calcium oxalate, brushite, monosodium urate, and uric acid. Criteria for significant seasonal variation included a significant difference in monthly means of risk factors, seasonal grouping of the data by the Student-Newman-Keuls multiple range test, consistent year-to-year trends and a physiologically significant range. Minimum urine volume of 1.54 +/- 0.70 SD L/day occurred in October while a maximum urine volume of 1.76 +/- 0.78 SD L/day was observed during February. Minimum urine pH of 5.94 +/- 0.64 SD was observed during July and August while a maximum pH of 6.18 +/- 0.61 SD was observed during February. Daily urinary excretion of sodium was lowest during August, 158 +/- 74 SD mEq/day and highest during February 177 +/- 70 SD mEq/day. The RS of brushite and uric acid were found to display significant pH-dependent seasonal variation with a maximum RS of uric acid 2.26 +/- 1.98 SD in June and a low of 1.48 +/- 1.30 SD in February. Maximum RS of brushite 2.75 +/- 2.58 was observed during February. Minimum RS of brushite 1.93 +/- 1.70 SD was observed in June. Phosphorus excretion displayed seasonal variation about a spring-fall axis with a maximum value 1042 +/- 373 SD mg/day in April and a minimum value of 895 +/- 289 SD mg/day. Urine volume, sodium, and pH were significantly lower during the summer (June, July, August) than in the winter (December, January, February). The RS of uric acid was higher, but that of brushite and monosodium urate was lower in the summer than in the winter. The seasonal changes observed in urine volume, pH, sodium, and the RS of brushite and uric acid are consistent with summertime sweating and increased physical activity. Seasonal variations in phosphorus excretion are probably dietary in origin. The summertime was characterized by an increased propensity for the crystallization of uric acid but not of calcium oxalate or calcium phosphate.     

Cardiovascular Implantable Device Infections

As life expectancy continues to increase and biotechnology advances, the use of cardiovascular implantable devices will continue to rise. Unfortunately, despite modern medical advances, the infection and mortality rates remain excessively elevated. This article reviews the pathophysiology and general concepts of cardiac device–related infections, including the physical and chemical characteristics of the medical device, host response to the medical device, and the microbiologic virulence factors. Infections of the most commonly utilized cardiovascular implantable devices, including cardiovascular implantable electronic devices, bioprosthetic and mechanical valves, ventricular assist devices, total artificial hearts, and coronary artery stents, are reviewed in detail.     

In vitro potency and in vivo efficacy of a novel bis-indole antimicrobial compound in reducing catheter colonization

Vascular catheters coated with a novel antimicrobial agent (MBX1631) were studied for their ability to protect against bacterial colonization in vitro and in a rabbit model. MBX1631-coated catheters were significantly less likely to become colonized than control catheters both in vitro and in vivo (P < 0.001). Furthermore, device-associated infection was significantly lower in MBX1631-coated catheters than in uncoated ones (P < 0.005).     

Diagnosis of Catheter-Related Bloodstream Infections: Is it Necessary to Culture the Subcutaneous Catheter Segment?

In order to determine the diagnostic usefulness of culturing the subcutaneous catheter segment, an analysis was performed using data derived from two prospective, randomized studies that included 479 patients with central venous catheters and 13 episodes of catheter-related bacteremia. The results indicate that quantitative culture, using the roll-plate and sonication methods, of the subcutaneous catheter segment did not add to the diagnostic yield (sensitivity, 83–100%; specificity, 82–97%; negative predictive value, 100%) of semiquantitative and quantitative catheter-tip cultures or aid in identifying catheter-related bloodstream infections. Electronic Publication