Changes in the envelope glycoprotein ectodomains of a nonpathogenic simian-human immunodeficiency virus (SHIV-89.6) that was serially passaged in vivo have been shown to be responsible for the increased pathogenicity of the resulting virus, SHIV-KB9 (G. B. Karlsson, et al., J. Exp. Med. 188:1159-1171, 1998). The 12 amino acid changes in the envelope glycoprotein ectodomains resulted in increased chemokine receptorbinding and syncytium-forming abilities. Here we identify the envelope glycoprotein determinants of these properties. A single amino acid change in the gp120 third variable (V3) loop was both necessary and sufficient for the observed increase in the binding of the SHIV-KB9 gp120 glycoprotein to the CCR5 chemokine receptor. The increased syncytium-forming ability of SHIV-KB9 involved, in addition to the V3 loop change, changes in the second conserved (C2) region of gp120 (residue 225) and in the gp41 ectodomain (residues 564 and 567). The C2 and gp41 ectodomain changes influenced syncytium formation in a cooperative manner. Changes in the V1/V2 gp120 variable loops exerted a negative effect on syncytium formation and chemokine receptor binding, supporting a previously described role of these changes in immune evasion. The definition of the passageassociated changes that determine the efficiency of chemokine receptor binding and membrane fusogenicity will allow evaluation of the contribution of these properties to in vivo CD4-positive lymphocyte depletion.

The pathogenesis of sepsis involves complex interaction between the host and the infecting microorganism. Bacterial recognition and signaling are essential functions of the cells of innate immune systems and drive a coordinated immune response. One of the more intriguing aspects of sepsis is the fact that the protective and damaging host response are part of the same process, that is, the inflammatory response that is aimed to control the infectious process also underscores many of the pathophysiological events of sepsis. The discovery of Toll-like receptors (TLRs) in humans, and the early recognition of TLR-4 as the receptor that signals LPS bioactivity were major breakthroughs not only in the field of sepsis but also in immunology as a whole. In this article, we aimed to review TLR expression and signaling in the context of sepsis. The results obtained by our group show that TLR and other cellular surface receptors may be differently regulated on mononuclear cells and neutrophils, and that they are dynamically modulated across the stages of sepsis. Toll-like receptor signaling gene expression in mononuclear cells is decreased in more severe forms of the disease. In contrast, up-regulated genes are seen along the clinical spectrum of sepsis in neutrophils.

The decline in the incidence of SCC is likely to be associated with the known decrease in the frequency of smoking among Singaporeans. In contrast, there appears to be a trend toward an increase in the incidence of adenocarcinoma in Singapore, although the absolute incidence remains relatively low. This may be due to the associated rise in the frequency of reflux esophagitis and obesity in Singapore.

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There is a growing number of elderly kidney transplant (Ktx) recipients. Elderly recipients present lower acute rejection rates but higher incidence of infection and malignancies. Aging per se seems to result in a shift to memory profile and chronic kidney disease (CKD) in premature immunological aging. Understanding aging and CKD effects on the immune system can improve elderly Ktx immunosuppression. We analyzed the effects of aging and CKD in the immune system, comparing healthy adults (HAd) (n=14, 26±2y), healthy elderly (HEld) (n=15, 79±7y), end stage renal disease (ESRD) adults (EnAd) (n=18, 36±7y) and ESRD elderly (EnEld) (n=31, 65±3y) prior to Ktx regarding their naïve, memory and regulatory T and B peripheral lymphocytes. Aging and ESRD presented additive effect decreasing absolute numbers of B and T-lymphocytes, affecting memory, naive and regulatory subsets without synergic effect. Both resulted in higher percentages of T memory subsets and opposing effects on regulatory T (TREG) subsets, higher percentage in aging and lower in ESRD. Combined effect of aging and ESRD also resulted in higher regulatory B cell percentages. In addition to global lymphopenia and TCD4+ memory shift in both aging and ESRD, aging shifts to an immunoregulatory profile, inducing a increase in TREG percentages, contrasting with ESRD that decreases TREGs. Differential immunosuppression regimens for elderly Ktx may be required. (ClinicalTrials.gov number: NTC01631058).

Laparoscopic omental patch repair offers a safe alternative to the conventional method and causes less postoperative pain.

Delay in the start of effective treatment for HCC using RF ablation may be associated with poorer patient survival.

No abstract