Ventricular pre-excitation in the general population: a study on the mode of presentation and clinical course

OBJECTIVE—To describe the mode of presentation and the clinical course of patients with ventricular pre-excitation (Wolff-Parkinson-White (WPW) syndrome), with special emphasis on asymptomatic cases in the general population.
METHODS—Over an eight year period (1990-97) a prospective population based survey of cases with WPW pattern was conducted in a defined population in north west Greece (340 000 inhabitants). ECGs with WPW pattern were obtained from a widespread pool of ECGs within the health system.
RESULTS—During the study period, 157 cases with WPW pattern were identified (49 female, 108 male). Ages ranged from infants to 84 years, mean (SD) 49.1 (21.0) years in female and 39.6 (20.6) years in male subjects (p < 0.01); 78 (49%) had no history of syndrome related symptoms. Asymptomatic subjects (n = 77; 24 female, 53 male) were older than symptomatic subjects (mean age 46.7 (21.0) v 38.5 (20.6) years, p < 0.03). Documented supraventricular tachycardia was recorded in 27 patients (17%) and atrial fibrillation in 12 (8%) (mean age at first episode 31.2 (18.3) and 51.6 (20.7) years, respectively, p < 0.01). During follow up (mean 55 months) no case of sudden death occurred. Three asymptomatic subjects reported episodes of brief palpitation.
CONCLUSIONS—WPW pattern is more common, and diagnosed at a younger age, in men than in women. About half the patients with WPW pattern on ECG are asymptomatic at diagnosis and tend to remain so thereafter. No sudden cardiac death occurred during the study period.


Keywords: Wolff-Parkinson-White syndrome; epidemiology     

Thrombomodulin as a regulator of the anticoagulant pathway: implication in the development of thrombosis

Thrombomodulin is a cell surface-expressed glycoprotein that serves as a cofactor for thrombin-mediated activation of protein C (PC), an event further amplified by the endothelial cell PC receptor. The PC pathway is a major anticoagulant mechanism that downregulates thrombin formation and hedges thrombus formation. The objectives of this review were to review recent findings regarding thrombomodulin structure, its involvement in the regulation of hemostasis and further discuss the implication, if any, of the genetic polymorphisms in the thrombomodulin gene in the risk of development of thrombosis. We performed a literature search by using electronic bibliographic databases. Although the direct evaluation of risk situations associated with thrombomodulin mutations/polymorphisms could be of clinical significance, it appears that mutations that affect the function of thrombomodulin are rarely associated with venous thromboembolism. However, several polymorphisms are reported to be associated with increased risk for arterial thrombosis. Additionally studies on knock out mice as well studies on humans bearing rare mutations suggest that thrombomodulin dysfunction may be implicated in the pathogenesis of myocardial infraction.     

Thermoelectric Performance of Mechanically Mixed BixSb2-xTe3—ABS Composites

In the current study, polymer-based composites, consisting of Acrylonitrile Butadiene Styrene (ABS) and Bismuth Antimony Telluride (Bi_xSb_2−xTe₃), were produced using mechanical mixing and hot pressing. These composites were investigated regarding their electrical resistivity and Seebeck coefficient, with respect to Bi doping and Bi_xSb_2-xTe₃ loading into the composite. Experimental results showed that their thermoelectric performance is comparable—or even superior, in some cases—to reported thermoelectric polymer composites that have been produced using other complex techniques. Consequently, mechanically mixed polymer-based thermoelectric materials could be an efficient method for low-cost and large-scale production of polymer composites for potential thermoelectric applications.     

Clinical evaluation of an HIV-1 and HCV assay and demonstration of significant reduction of the HCV detection window before seroconversion

BACKGROUND: One HIV-1 and HCV assay simultaneously detects HIV-1 and HCV RNA (Procleix, Chiron Corp.). The main intended use of the assay is the testing of blood and blood products in blood banking. STUDY DESIGN AND METHODS: To evaluate the clinical sensitivity of the assay, 164 anti-HIV-1+ and 160 anti-HCV+ patients of different viral load were tested. The assay specificity was determined in 1000 HIV-1- and HCV-seronegative blood donors. The ability of the assay to detect different HCV genotypes was investigated in a total of 40 patients of different genotypes (1-4). Furthermore, to investigate the reduction of the HCV window phase before seroconversion, serial samples of 25 hemodialysis patients who seroconverted to anti-HCV were also tested. RESULTS: The assay detected all 60 HIV-1-infected patients with a viral load of greater than 50 copies per mL and 48 of 104 patients with a viral load of less than 50 copies per mL. Moreover, all 60 patients with an HCV RNA load of greater than 521 IU per mL and 7 of 100 patients with a viral load of less than 50 IU per mL tested positive. The assay specificity was found to be 100 percent. In addition, all 40 patients of different HCV genotypes were successfully detected. Finally, the median time that the assay detected HCV infection before second- and third-generation anti-HCV assay was found to be 183 and 91 days, respectively. CONCLUSION: The assay sensitivity and specificity, its ability to detect different HCV genotypes, and the significant reduction of window period of HCV infection further support its use for improving the safety of blood and blood products.     

The role of MR imaging in staging femoral head osteonecrosis

Reliability, accuracy and prognostic value of any classification system are important in evaluation and treatment of femoral head osteonecrosis. The purpose of the present study was to correlate the plain radiographs with MRI in femoral head osteonecrosis. Between 2000 and 2005, 115 hips (72 patients) were evaluated and classified according to the ARCO classification criteria with the use of plain radiographs and additional application of MRI. Classification was performed by consensus between a musculoskeletal radiologist and an orthopaedic surgeon. Sensitivity (SEN), specificity (SP), positive (PPV) and negative (NPV) predictive value of X-rays were estimated. According to MRI, 17 hips were classified as stage I, 25 as stage II, 48 as stage III and 25 as stage IV. The SEN, SP, PPV and NPV of plain radiographs were for stage II 88%, 90.5%, 78.6% and 95%; for stage III 79.2% 82%, 80.8% and 87.2%; for stage IV 76%, 100%, 100% and 90.9%, respectively. The agreement between plain radiographs and MRI was 80.6% for staging the disease, 71.2% for recording the location of the osteonecrotic lesion, 67.1% for evaluating the size of the lesion, 79.2% for the presence of collapse of the articular surface and 56.3% for the degree of collapse. In conclusion, the ARCO classification could miss important information in stages II and III, where treatment aims at preservation of the hip joint integrity. The results of the present study suggest that MRI should be incorporated in the classification of osteonecrosis (stages II and III), to add accuracy and prognostic value.     

Green tea,white tea,and Pelargonium purpureum increase the antioxidant capacity of plasma and some organs in mice

ObjectiveWe tested in mice the hypothesis that ingestion of infusions of green tea, white tea, or the aromatic plant Pelargonium purpureum increases total antioxidant capacity (TAC) of plasma and organs.MethodsTwenty-five mice were randomly assigned to five groups, each of which received by gavage 0.1 mL of infusion from green tea, white tea, or P. purpureum (8 g/100 mL of water) or catechin (0.01 g/100 mL) or water for 5 consecutive days. On the fifth day the animals were euthanized. Blood was taken by heart puncture and the heart, lungs, liver, spleen, kidney, and brain were removed. TAC was measured in plasma and in all organ homogenates with the ferric reducing antioxidant power assay and in selected organ homogenates by the total radical-trapping antioxidant parameter assay.ResultsGreen tea and P. purpureum increased TAC in the plasma and lungs, whereas green tea, white tea, and catechin increased TAC in heart homogenates. No effect was observed on the liver, brain, spleen, and kidney homogenates in comparison with the water control with the ferric reducing antioxidant power assay or the total radical-trapping antioxidant parameter assay.ConclusionThese results suggest that green tea, white tea, and P. purpureum exhibit antioxidant effects in vivo that may be observed not only in plasma but also in some organs.     

Antibody Responses to Hepatitis C Virus by Second-Generation Immunoassays in a Cohort of Patients with Bleeding Disorders

The antibody responses and the prevalence patterns of antibodies to hepatitis C virus (anti-HCV) in a cohort of patients (n = 210) with bleeding disorders were studied using a first-generation and a second-generation enzyme immunoassays (EIA-1, EIA-2) as well as a second-generation recombinant immunoblot assay (RIBA-2). The anti-HCV prevalence as determined by EIA-1 and EIA-2 was 183/210 (87.1%) and 197/210 (93.8%), respectively (p = 0.0026). None of the 17 EIA-2(+)/EIA-1(-) samples was scored nonreactive by RIBA-2. At follow-up, samples of 123 patients were tested. Twenty-nine out of 111 patients reactive by EIA-1 seroreverted according to EIA-1 while the seroreversion rate with EIA-2 was 0 out of the 121 (p < 10(-8)). The anti-HCV prevalence by EIA-2 was 150/154 (97.4%) in anti-HIV-1-positive individuals and 47/56 (83.9%) in the anti-HIV-1-negative ones (p = 0.001). However, high assay signals (OD 492 nm > 2.0) were observed in 94/150 (62.7%) and 45/47 (95.7%) of the anti-HIV-1-positive and -negative patients, respectively (p = 10(-5)). The decreasing anti-HCV reactivity among anti-HIV-1-positive individuals was mainly due to diminishing c33c reactivity. Seroconversion to anti-HCV was observed in 3/7 (42.9%) cases with acute icteric non-A, non-B hepatitis by both EIA-1 and EIA-2, while the remaining 4 cases had detectable levels of anti-HCV 1-18 months before the acute episode.