TRENDS IN THE DIAGNOSIS OF HUMAN IMMUNODEFICIENCY VIRUS

Ever since the first HIV case reported, there is a dramatic increase in the prevalence of HIV infection which urged the need for an effective diagnostic method.  There are several improvements in diagnostic methods employing various technologies to screen for HIV infection using enzyme immunoassays and rapid diagnostic tests which simultaneously detect antigen and antibody with significantly reduced window period.  Further, western blot or immunofluorescence methods are used to confirm the results. Nucleic acid amplification tests, though sensitive, are expensive and hence not employed for screening but instead used to monitor the antiretroviral drug response. In spite of appreciable advancements in the sensitivity and specificity of the detection techniques, the algorithms are still the method of choice for ensuring the accuracy of test results

Rapid and Highly Informative Diagnostic Assay for H5N1 Influenza Viruses

A highly discriminative and information-rich diagnostic assay for H5N1 avian influenza would meet immediate patient care needs and provide valuable information for public health interventions, e.g., tracking of new and more dangerous variants by geographic area as well as avian-to-human or human-to-human transmission. In the present study, we have designed a rapid assay based on multilocus nucleic acid sequencing that focuses on the biologically significant regions of the H5N1 hemagglutinin gene. This allows the prediction of viral strain, clade, receptor binding properties, low- or high-pathogenicity cleavage site and glycosylation status. H5 HA genes were selected from nine known high-pathogenicity avian influenza subtype H5N1 viruses, based on their diversity in biologically significant regions of hemagglutinin and/or their ability to cause infection in humans. We devised a consensus pre-programmed pyrosequencing strategy, which may be used as a faster, more accurate alternative to de novo sequencing. The available data suggest that the assay described here is a reliable, rapid, information-rich and cost-effective approach for definitive diagnosis of H5N1 avian influenza. Knowledge of the predicted functional sequences of the HA will enhance H5N1 avian influenza surveillance efforts

Kinetics of dissociation of tris-(2,2 '-bipyridyl) iron(II) in water solubilized by Triton X-100 reverse micelles

The dissociation of tris-(2,2'-bipyridyl) iron(II) ([Fe(bipy)(3)](2+)) has been studied in the Triton X-100/hexanol/cyclohexane reverse micellar medium. The reaction obeys simple first-order kinetics with no evidence of autoinhibition. The first-order rate constant (k(1)) has been determined at different values of W ([H2O]/[Triton X-100]). The rate (k(1)) decreases with increasing value of W. k(1) also increases with increase in Triton X-100 concentration at constant values of W, showing that the reaction takes place at greater speed at the micellar interface. The kinetic results can be interpreted by the monomolecular pseudo-phase model. The effect of W on rate (k(1)) is more pronounced in the range of W from 1.55 to 4.2 but less pronounced at higher W. The reaction is further accelerated by Cl- and SCN- ions and the kinetic results provide evidence for the formation of ion pairs between the cation [Fe(bipy)(3)](2+) and each of these anions. The formation of such ion pairs has not been observed in aqueous medium but has been reported earlier in aqueous-alcohol mixtures. This result therefore provides evidence for the lower micropolarity of solubilized water compared to ordinary water. (c) 200

Kinetics of basic hydrolysis of tris (1,10-phenanthroline) iron(11) in Triton X 100/hexanol/water reverse micelles in cyclohexane

The kinetic study of dissociation of the complex tris (1,10-phenanthroline) iron(11) in the presence of OH- ion has been carried out in the water pools of non-ionic reverse micelles of Triton X 100, hexanol in cyclohexane. The reaction shows completely different kinetic features at low and high W values. The pseudo first order rate constant (kobs) varies linearly with the effective concentration of sodium hydroxide in the water pool ([OH-]e) at high values of W (W = 14.0 and 10.6), on decreasing W, the kobs versus [OH-]e plots concave upwards showing higher order dependence of kobs on [OH -]e. The kinetics has been accounted for by a mechanism involving intermediate ion-pair formation between oppositely charged ions. The significant increase in rate in reverse micellar media as compared to aqueous media is due to the lower micropolarity of the waterpools in this reverse micellar media, which facilitates the ion-pair formation between oppositely charged ions.© Elsevie

Persistence of SARS-CoV-2-Specific IgG in Children 6 Months After Infection, Australia

The duration of the humoral immune response in children infected with severe acute respiratory syndrome coronavirus 2 is unknown. We detected specific IgG 6 months after infection in children who were asymptomatic or had mild symptoms of coronavirus disease. These findings will inform vaccination strategies and other prevention measures

Immune responses to SARS-CoV-2 in three children of parents with symptomatic COVID-19

Compared to adults, children with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have predominantly mild or asymptomatic infections, but the underlying immunological differences remain unclear. Here, we describe clinical features, virology, longitudinal cellular, and cytokine immune profile, SARS-CoV-2-specific serology and salivary antibody responses in a family of two parents with PCR-confirmed symptomatic SARS-CoV-2 infection and their three children, who tested repeatedly SARS-CoV-2 PCR negative. Cellular immune profiles and cytokine responses of all children are similar to their parents at all timepoints. All family members have salivary anti-SARS-CoV-2 antibodies detected, predominantly IgA, that coincide with symptom resolution in 3 of 4 symptomatic members. Plasma from both parents and one child have IgG antibody against the S1 protein and virus-neutralizing activity detected. Using a systems serology approach, we demonstrate higher levels of SARS-CoV-2-specific antibody features of these family members compared to healthy controls. These data indicate that children can mount an immune response to SARS-CoV-2 without virological confirmation of infection, raising the possibility that immunity in children can prevent the establishment of SARS-CoV-2 infection. Relying on routine virological and serological testing may not identify exposed children, with implications for epidemiological and clinical studies across the life-span