Parvovirus B19 viremia in children with systemic lupus erythematosus

Background: Parvovirus B19 infection may present with fever, rash, nonerosive arthritis, hepatitis, anemia, thrombocytopenia, leucopenia and positive ANA, B19 infection may be misdiagnosed as new onset systemic lupus erythematosus. At the same time, B19 infection and systemic lupus erythematosus may occur simultaneously in some patients. A casual relationship between B19 infection and classic idiopathic systemic lupus erythematosus has not been demonstrated yet. Objectives: This study was undertaken to investigate the seroprevalence of parvovirus B19 in SLE patients and to search for the different correlates of this viremia with positive results. Methods: This case-control study was conducted on 30 patients with SLE and 30 normal controls. All the children were subjected to detailed medical history, Clinical examination, laboratory estimation as sera from them were examined for parvovirus B19 infection by serological assays using nested polymerase chain reaction and IgG and IgM antiB19 antibodies by ELISA. Results: Parvovirus B19 DNA was detected in 11 of the 30 patients with SLE (33.3 percent) while it was not detected in any of our normal controls. Of the 11 patients with B19 DNA, only two had IgG anti-B19 antibody and one had IgM anti-B19 antibodies, whereas IgG and IgM anti-B19 antibodies were detected in 11(57.8%)and 9 (47.3%)of 19 SLE patients without B19 DNA respectively. B19 DNA was found more commonly in sera from SLE patients without anti-B19 antibodies than in those with anti-B19 antibodies (P < 0.05). Conclusions: parvovirus B19 might induce either idiopathic SLE in a person who is genetically susceptible or it might induce a SLE-like picture. Parvovirus B19 infection in patients with SLE may be due to lack of anti-B19 antibodies because of either the immunocompromised nature of the host or the use of immunosuppressive drugs. There was a higher prevalence of hypocomplementemia in patients with parvovirus B19 viremia than in those without parvovirus. Keywords: Human parvovirus B19, Systemic lupus erythematosus, Nested PCREgypt J Pediatr Allergy Immunol 2011;9(2):71-7

An optimum reactance one-port compensator for harmonic mitigation

The installation of electronic devices, digital equipment, and nonlinear loads in both industrial and domestic applications have dramatically increased in recent years, which in turn increased the level of harmonics in the system. Harmonic distortion is widely recognized as a significant cause of damage to, and mat-operation of electrical equipment. A harmonic filter can eliminate the potentially dangerous effects of harmonic currents created by nonlinear loads. There are two types of harmonic filters: passive filters and active filters. Passive filters are inexpensive compared with most mitigating devices. In this paper, reactance one-port compensator is designed for current harmonic mitigation. The optimal parameters the filter are determined using the Branch and Reduce Optimization Navigator (BARON) Nonlinear Programming Solver in the General Algebraic Modeling System (GAMS)

Impacts of Wind Power Variability on Generation Costs - An Overview

Although wind power is sustainable, environmental friendly and relatively inexpensive source of electricity, the effects of its intermittent nature on power systems need to be carefully investigated. This paper presents an up-to-date overview of the impacts of wind power variability on overall generation cost. Recent case studies from different utilities around the globe demonstrated that wind integration costs are much lower than anticipated by earlier studies