Serological, molecular and clinical correlates of dengue from a tertiary care centre in Chennai, India.

Dengue disease is caused by dengue viruses 1-4 and has been ranked by the World Health Organisation (WHO) as the fastest spreading vector-borne viral disease. Dengue is often underreported and misdiagnosed due to a wide spectrum of clinical manifestations. Diagnosis of dengue is based on clinical case definitions and laboratory methods. Newer case definitions of dengue have been formulated by clinical studies in order to improve case detection. Owing to its epidemic potential, mortality and morbidity, there is a need for a rapid and accurate diagnostic assay for dengue in order to help the clinician in the early detection of cases and to prevent disease progression. A duplex real time PCR targeting the 3'UTR region for rapid and simultaneous detection of all dengue viruses serotypes (1-4) was standardized based on published literature. About 150 patients with acute undifferentiated febrile illness classified based on the 2009 WHO dengue case definition were tested using the duplex real time dengue PCR. Sequencing based PCR was performed on selected PCR positive samples for partial nucleotide sequence of the CprM gene and a phylogenetic tree was constructed. Statistical analysis was done using the MedCalc software. Out of the 126 patients classified as dengue disease positive, according to the 2009 WHO dengue case definition, 54% had "probable dengue", 43% had "dengue with warning signs" and 3% had "severe dengue". The performance of the duplex real time PCR was assessed among the various clinical groups of dengue and it was found that in the "dengue with warning signs group" PCR had a positive predictive value of 85.29% (range - 68.94% to 95.05%) when compared with dengue NS1 ELISA. The average time for PCR positivity was found to be four days from the onset of illness. The cycling threshold values obtained from real time PCR were used as a semi quantitative measure of viremia. Accordingly, there was a relatively low CT value among the "warning signs dengue group" when compared to the "probable dengue group". The use of the duplex PCR is suggested in the early diagnosis of dengue, especially in the 'warning signs' group of patients as they showed a higher positivity rate. Also, the use of the resultant CT value as a semi-quantitative measure of viremia will assist the clinician in early diagnosis and prevention of disease development.

B cells mediate chronic allograft rejection independently of antibody production.

Chronic rejection is the primary cause of long-term failure of transplanted organs and is often viewed as an antibody-dependent process. Chronic rejection, however, is also observed in mice and humans with no detectable circulating alloantibodies, suggesting that antibody-independent pathways may also contribute to pathogenesis of transplant rejection. Here, we have provided direct evidence that chronic rejection of vascularized heart allografts occurs in the complete absence of antibodies, but requires the presence of B cells. Mice that were deficient for antibodies but not B cells experienced the same chronic allograft vasculopathy (CAV), which is a pathognomonic feature of chronic rejection, as WT mice; however, mice that were deficient for both B cells and antibodies were protected from CAV. B cells contributed to CAV by supporting splenic lymphoid architecture, T cell cytokine production, and infiltration of T cells into graft vessels. In chimeric mice, in which B cells were present but could not present antigen, both T cell responses and CAV were markedly reduced. These findings establish that chronic rejection can occur in the complete absence of antibodies and that B cells contribute to this process by supporting T cell responses through antigen presentation and maintenance of lymphoid architecture.

Cytotoxicity and degree of conversion of orthodontic adhesives.

OBJECTIVES: To test the hypothesis that there is no difference in the cytotoxicity related to the modes of polymerization of five commercially available orthodontic bonding resins, with and without an oxygen-inhibited layer (OIL), and to evaluate the degree of conversion (DC) of these resins and correlate this to cytotoxicity. MATERIALS AND METHODS: Five commercially available orthodontic bonding resins were tested for cytotoxicity and DC. Thirty-six disks of standardized dimensions, for each resin, were used for cytotoxicity assessment. Half of them were washed with 99% acetone to remove the OIL (washed resins), and the remaining disks were left intact (intact resins). Glass disks were used as a control. Vero cells were exposed to intact and washed resins on day 1. Cell viability was determined by tetrazolium bromide reduction assay 1, 3, and 6 days after exposure. The DC of the adhesive specimens of each resin, prepared with a procedure identical to the clinical bonding process, was assessed by Fourier transform infrared spectroscopy. RESULTS: Single-cured systems were comparatively less cytotoxic than dual-cured systems. With removal of the OIL, increased cell viability was noted only with two resins on all three days. Resins tested showed differences in DC. A positive correlation was demonstrated by two resins. CONCLUSION: The hypothesis is rejected. Single-cured systems are superior to dual-cured systems in exhibiting comparatively less toxicity and higher DC. A significant positive correlation was not established between cytotoxicity and DC.