Impact of human immunodeficiency virus type 1 reverse transcriptase inhibitor drug resistance mutation interactions on phenotypic susceptibility.

The role specific reverse transcriptase (RT) drug resistance mutations play in influencing phenotypic susceptibility to RT inhibitors in virus strains with complex resistance interaction patterns was assessed using recombinant viruses that consisted of RT-PCR-amplified pol fragments derived from plasma HIV-1 RNA from two treatment-experienced patients. Specific modifications of key RT amino acids were performed by site-directed mutagenesis. A panel of viruses with defined genotypic resistance mutations was assessed for phenotypic drug resistance. Introduction of M184V into several different clones expressing various RT resistance mutations uniformly decreased susceptibility to abacavir, lamivudine, and didanosine, and increased susceptibility to zidovudine, stavudine, and tenofovir; replication capacity was decreased. The L74V mutation had similar but slightly different effects, contributing to decreased susceptibility to abacavir, lamivudine, and didanosine and increased susceptibility to zidovudine and tenofovir, but in contrast to M184V, L74V contributed to decreased susceptibility to stavudine. In virus strains with the nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations K101E and G190S, the L74V mutation increased replication capacity, consistent with published observations, but replication capacity was decreased in strains without NNRTI resistance mutations. K101E and G190S together tend to decrease susceptibility to all nucleoside RT inhibitors, but the K103N mutation had little effect on nucleoside RT inhibitor susceptibility. Mutational interactions can have a substantial impact on drug resistance phenotype and replication capacity, and this has been exploited in clinical practice with the development of fixed-dose combination pills. However, we are the first to report these mutational interactions using molecularly cloned recombinant strains derived from viruses that occur naturally in HIV-infected individuals.

A changing pattern of infection after major vascular reconstructions.

Wound and graft infection can occur in more than 40% of patients undergoing vascular reconstructions for peripheral arterial disease (PAD). A recent increase in the frequency and severity of infections, as well as a change in the microorganisms recovered, led us to undertake a retrospective case-controlled study of wound/graft infections at this institution. The medical records of all patients undergoing vascular reconstruction for PAD during the previous 36 months were reviewed. Patient demographics, graft location and conduit, infection location, causative microorganisms, and factors potentially associated with development of infection were recorded. Infections were classified according to a modification of the CDC criteria into superficial incisional, deep incisional, or involving the graft (body only, anastomosis without disruption, or anastomosis with disruption). Univariate and multivariate regression analyses were used to identify factors associated with the development of infection. Four hundred ten (84 aortic, 41 extraanatomic, and 285 infrainguinal) revascularization procedures were performed in 217 men and 193 women with a mean age of 62 years (range 43-88). The infection rate for the entire group was 11.0% (45/410). Eighty percent (36/45) occurred after infrainguinal reconstructions and 64% (29/45) of the infections involved the groin incision. Direct involvement of the graft occurred in 67% (30/45), and 27% (12/45) presented with anastomotic disruption. Of the infrainguinal infections, in situ and prosthetic reconstructions were associated with a significantly higher rate of infection than reversed vein grafts tunneled anatomically (p <0.001, chi-square analysis). Patients with nonautogenous grafts (24 expanded polytetrafluoroethylene and 2 bovine) presented with more advanced infections involving the graft (20/26 procedures) and were more likely to present with anastomotic disruption (11/26). Staphylococcus aureus was isolated in the majority of infections (64%) and in all cases involving graft disruption. Multivariate regression analysis identified the following factors associated with development of infection: previous hospitalization (p = 0.03), a younger age (p = 0.047), and the presence of a groin incision (p = 0.04). Twenty-five percent of graft infections resulted in major amputation, and 11% of patients with graft infection died as a result. The incidence, morbidity, and mortality of infections in vascular reconstructions for PAD are increasing dramatically, particularly in infrainguinal reconstructions involving groin incisions. Perioperative antibiotic selection should be modified to include coverage for all Staphylococcal subspecies and hospitalization before surgical procedures should be avoided.

Expression of Epstein-Barr virus latent genes in oral epithelium: determinants of the pathogenesis of oral hairy leukoplakia.

This retrospective study examined expression of Epstein-Barr virus (EBV) latent genes in oral epithelium from human immunodeficiency virus-seropositive subjects, to identify genes associated with the pathogenesis of oral hairy leukoplakia (HLP). Transcription of EBV latent genes was detected in tissues with productive EBV replication and, also, in normal oral epithelial tissues without EBV replication. Expression of the EBV EBNA-2 open-reading frame in oral epithelium was identified as an important cofactor associated with the pathogenesis of HLP. In vitro experiments suggested that a recombinant variant of the EBNA-2 gene may play a role in the pathogenesis of HLP, through modulation of EBNA-2 protein function.

Effect of Epstein-Barr virus replication on Langerhans cells in pathogenesis of oral hairy leukoplakia.

Epstein-Barr virus (EBV) replicates productively in oral hairy leukoplakia (HLP). One characteristic of human immunodeficiency virus (HIV)-associated HLP is a decreased oral epithelial Langerhans cell count. This prospective study tested the hypothesis that oral epithelial EBV replication decreases oral Langerhans cell counts. EBV replication in HLP was highly correlated with decreased oral Langerhans cell counts. Inhibition of EBV replication restored oral Langerhans cell counts to normal control levels, and the return of EBV replication after treatment resulted in a recurrent decline in oral Langerhans cell counts. Decreased oral Langerhans cell counts occurred independently of HIV infection, as demonstrated in HLP of otherwise healthy HIV-seronegative individuals. These results support the tested hypothesis and suggest that EBV manipulates and evades the mucosal immune response in oral epithelial infection. This novel EBV strategy for eliminating oral Langerhans cells may facilitate the persistence of oral epithelial EBV and may contribute to the pathogenesis of HLP.

Implicancias del control de calidad de preservativos en la prevención de las enfermedades de transmisión sexual / Legal impediment of quality control in the prevention of sexuals transmition diseases

Se realizó un estudio de control de calidad de los preservativos ofrecidos a la venta al público en Lima Cercado con la finalidad de determinar si cumple con los requisitos de control de calidad formulados por el ITINTEC y evaluar si son adecuados para la prevención de las ETS. Se utilizó un procedimiento de muestreo por conglomerados, utilizando como marco muestral el plano de Lima Cercado, los sectores fueron seleccionados utilizando una tabla de números aleatorios; se adquirieron 3 preservativos en cada sector obteniéndose una muestra de 96 unidades, las que fueron sometidas a los procedimientos de control de calidad formulados por el ITINTEC en las normas técnicas nacionales 399-146, 399-147. El 42.7 por ciento de las unidades fueron adquiridas en farmacias y 57.3 por ciento en puestos de venta ambulatoria; 86.5 por ciento corresponden a la marca Sultan producidos en Estados Unidos. Al ser sometidas a los procedimientos de control de calidad, 3 (3.13 por ciento) de las unidades fallaron en el ensayo de ausencia de perforaciones; 6 (6.25 por ciento) fallaron en el ensayo de resistencia de perforaciones; 6 (6.25 por ciento) no cumplían el espesor mínimo requerido, 6 (6.25 por ciento) fallaron en el ensayo de resistencia a la tensión y 1 (1.04) unidad tenía un tiempo de manufactura superior al de vencimiento. En total 15 unidades (15.63 por ciento intervalo de confianza del 95 por ciento con límites entre 9.02 por ciento y 24.46 por ciento) no cumplen los requisitos de control de calidad. No se encontraron diferencias estadísticamente significativas en cuanto a la calidad de los preservativos adquiridos en farmacias o en puestos de venta ambulatoria. Se revisó la literatura para discutir la eficacia preventiva del preservativo frente a las enfermedades de transmisión sexual ; existen evidencias que sustentan el efecto protector del preservativo, pero se necesitan estudios mejor diseñados para establecer de manera concluyente su efecto protector. Se concluye que los preservativos ofrecidos a la venta al público en Lima Cercado no cumplen los requisitos de control de calidad y por lo tanto no son adecuados para la prevención de las enfermedades de transmisión sexual