HIV testing. State of the art

Lack of Evidence for Molecular Mimicry in HIV-Infected Subjects

Previous studies in HIV patients have reported autoantibodies to several human proteins, including erythropoietin (EPO), interferon-α (IFN-α), interleukin-2 (IL-2), and HLA-DR, as potential mediators of anemia or immunosuppression. The etiology of these autoantibodies has been attributed to molecular mimicry between HIV epitopes and self-proteins. Here, the Luciferase Immunoprecipitation System (LIPS) was used to investigate the presence of such autoantibodies in HIV-infected adults. High levels of antibodies to HIV proteins such as capsid (p24), matrix (p17), envelope (gp41), and reverse transcriptase (RT) were detected using LIPS in both untreated and anti-retroviral-treated HIV-infected individuals but not in uninfected controls. LIPS readily detected anti-EPO autoantibodies in serum samples from subjects with presumptive pure red cell aplasia but not in any of the samples from HIV-infected or uninfected individuals. Similarly, subjects with HIV lacked autoantibodies to IFN-α, IL-2, HLA-DR and the immunoglobulin lambda light chain; all purported targets of molecular mimicry. While molecular mimicry between pathogen proteins and self-proteins is a commonly proposed mechanism for autoantibody production, the findings presented here indicate such a process is not common in HIV disease.

Special populations: The management of seizures in HIV-positive patients

An increasing percentage of patients with new-onset seizures are HIV positive. The evaluation and management is distinctly different from managing the non-HIV-infected patient. Clinicians must be familiar with comorbid infectious etiologies and the relative value of electroencephalogram, imaging, and serum and cerebrospinal fluid laboratory tests. Traditional antiepileptic drug (AED) therapies are contraindicated and may lead to increased HIV viral replication through either directed cellular mechanisms or interference with antiretroviral therapies. Newer AEDs have pharmacokinetic properties that make them reasonable choices, although none have been specifically studied for efficacy or safety in HIV. Lastly, optimal choice of an AED should reflect commonly encountered neurologic and psychiatric comorbidities.

A biomechanical comparison of three lower extremity tendons for ligamentous reconstruction about the knee

PURPOSE

The purpose of this investigation was to evaluate 3 previously unreported allograft tendons for use in knee surgery. These are the doubled tibialis anterior (TA), doubled tibialis posterior (TP), and doubled peroneus longus (PL) tendons.

TYPE OF STUDY

A biomechanical evaluation of the properties of the TA, TP, and PL.

METHODS

Sixteen fresh-frozen cadaveric lower limbs were used for testing. All specimens had the TA, TP, and PL tendons harvested. All specimens were tested in a custom-designed hydraulic testing machine using dry ice clamps. Each tendon was elongated at a rate of 1 mm/s. Load and displacement were recorded with an analog to digital interface board. Stiffness, modulus of elasticity, and stress and strain at failure were calculated.

RESULTS

The average tested lengths of the TA, TP, and PL were 37 cm (range, 13-68 cm), 33 cm (range, 7-74 cm), and 42 cm (range, 17-69 cm), respectively. The average cross-sectional areas of the doubled TA, TP, and PL were 38 mm2, 48 mm2, and 37 mm2, respectively. The average failure loads for the doubled TA, TP, and PL tendons were 3,412 N, 3,391 N, and 2,483 N, respectively. The maximum stresses of the 3 tendons did not differ significantly (85-108 Mpa). The TA had the greatest stiffness (344 N/mm), followed by the TP (302 N/mm) and the PL (244 N/mm). Previous authors have documented the biomechanical strength of grafts for ACL reconstruction between 1,700 and 2,900 Newtons. The ultimate tensile strength and stiffness reported for the TA and TP grafts exceeded that for all previously reported grafts, including the doubled semitendinosus-gracilis.

CONCLUSIONS

The TA, TP, and PL tendons showed excellent biomechanical properties when compared with historical data evaluating other graft sources. The biomechanical properties observed for the TA, TP, and PL were noted in specimens despite an average age of 78.3 years.

Creative Teaching Strategies

Today's nursing students feel pressured to complete research-based professional papers. Reasons that these assignments cause feelings of anxiety may be due to learners' poor writing/thinking skills, low literacy levels, lack of attention when traditional strategies are used, or expectations of entertaining teaching methods. Creative teaching strategies, using a story-telling and personification approach, may assist nurse educators to improve students' attention, retention and comprehension of primary concepts in their nursing courses.

Problems in interpreting HIV sentinel seroprevalence studies

Estimating human immunodeficiency virus (HIV) prevalence from sentinel seroprevalence studies is difficult. We characterize these studies and show that most are investigations of incompletely defined (hypothetical) cohorts and are usually based on nonprobability samples. Prevalence in HIV sentinel serosurveys is also time-averaged and vulnerable to several time-dependent sources of bias (e.g., migration, deaths, and changes in incidence). Assumptions must be made that these time-dependent biases did not meaningfully affect the data, and this can be helped by reducing the period of investigation. Furthermore, we show that "reliability" can not be adequately measured by standard error, that "internal validity" is vulnerable to self-selection bias and laboratory problems, and that "generalizability" is limited. We propose that what is needed is a procedure (like formal metaanalysis methods) incorporating information from several separate HIV sentinel seroprevalence studies, in a manner that is reproducible and can take into consideration the differences between studies.

Specific western blot bands are associated with initial CD4+ lymphocyte counts in human immunodeficiency virus seroconverters. The Navy HIV Working Group

The Western blot is the most widely used confirmatory test for determining human immunodeficiency virus (HIV) seropositivity. Specific bands in the Western blot indicate antibody responses to various portions of HIV or its precursors, and each is assigned a score from 0 to 3+. While the precise role of humoral antibody responses has not been fully established, specific antibody responses might influence the course of HIV infection. This study investigated the association between antibody reactivity to nine principal Western blot bands and initial CD4+ counts among 877 Navy and Marine Corps personnel during 1988 to 1991. Multiple regression was used to evaluate the strength and significance of the associations and to adjust for age and estimated duration of infection. Strong antibody responses to the p24 core (P < 0.05), p53 reverse transcriptase (P < 0.005), and p55 core precursor (P < 0.0001) antigens were associated with higher initial CD4+ counts, with 33 to 48 additional cells/mm3 associated with each unit increase in the Western blot score, according to a multiple regression analysis which controlled for age and duration of infection (maximum 24 months). By contrast, antibodies to the gp41 transmembrane antigen (P < 0.0001) were associated with lower initial CD4+ counts. Each unit increase in the gp41 band was associated with 76 fewer CD4+ cells/mm3. A negative association was also observed for the gp160 envelope precursor antigen, with each unit increase in reactivity associated with 51 fewer CD4+ cells, although this association was not statistically significant (P = 0.09).(ABSTRACT TRUNCATED AT 250 WORDS)

Risk of human immunodeficiency virus type 1 transmission through breastfeeding

Detection of human immunodeficiency virus type 1 (HIV-1) in breast milk by culture and polymerase chain reaction does not necessarily mean that breastfeeding is a route of transmission, although evidence from several case-reports points in that direction. We undertook a systematic review of published studies meeting criteria that allowed determination of quantitative risk of transmission via breastfeeding. Based on four studies in which mothers acquired HIV-1 postnatally, the estimated risk of transmission is 29% (95% Cl 16-42%). Analysis of five studies showed that when the mother was infected prenatally, the additional risk of transmission through breastfeeding, over and above transmission in utero or during delivery, is 14% (95% Cl 7-22%). Where there are safe alternatives to breastfeeding, universal named testing of pregnant women would provide an opportunity to advise more infected women not to breastfeed and might thereby reduce the number of vertically infected children. Since breastfeeding protects against infant deaths from infectious diseases, breastfeeding is still recommended where infectious diseases are a common cause of death in childhood, despite the additional risk of HIV transmission.

AIDS and arthroscopic surgery

There are an estimated 8 to 10 million people worldwide infected with human immunodeficiency virus (HIV). The true extent of infection in the population is unknown, and many are unaware of their HIV status. Arthroscopic and arthroscopically assisted surgery is less invasive and bloody than other orthopaedic procedures, and seemingly less hazardous to surgeons. Nevertheless, the potential for exposure exists. Arthroscopic surgeons routinely experience gown, face-mask and shoe-cover saturation from the splashing of blood-tainted irrigation fluid. Glove perforations by needles, sharps, and bone fragments can occur. Bone and tissue allografts pose risks to both surgeon and patient, as HIV has been recovered from fresh, frozen and freeze-dried specimens. The process of cleaning and disinfecting arthroscopes adequately can damage these expensive devices. This article addresses the safeguards that arthroscopic surgeons should take to prevent exposure to HIV. Effective sterilizing and disinfecting techniques for arthroscopes are also discussed.