Prevalence and determinants of HIV-1 subtypes in Canada: enhancing routinely collected information through the Canadian HIV Strain and Drug Resistance Surveillance Program.
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Biomedical subjects
Publications and source records attributed to J Preiksaitis.
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We reviewed the clinical and laboratory findings for 19 cases of hantavirus pulmonary syndrome (HPS) identified either serologically or by immunohistochemical testing of archival tissue at our tertiary care center. Fever (95%), cough (89%), and dyspnea (89%) were the most common presenting symptoms. The most prevalent presenting signs were respiratory abnormalities (95%) and tachycardia (84%). Common laboratory findings included thrombocytopenia (95%) and leukocytosis (79%). Elevated aspartate aminotransferase and lactate dehydrogenase levels were found in all patients tested. Intubation was required in 58% of the patients, and inotropic support was required in 53%. Our study confirms that serological responses appear early during clinical illness, making the enzyme immunoassay a useful tool for the diagnosis of acute HPS. The mortality (26%) and severity of disease that we observed among patients with HPS appear to be less than those reported elsewhere.
Forty percent of women with primary cytomegalovirus (CMV) infections during pregnancy infect their fetuses with complications for the baby varying from mild to severe. How CMV crosses the syncytiotrophoblast, the barrier between maternal blood and fetal tissue in the villous placenta, is unknown. Virus may cross by infection of maternal cells that pass through physical breaches in the syncytiotrophoblast or by direct infection of the syncytiotrophoblast, with subsequent transmission to underlying fetal placental cells. In this study, we show that pure (>99.99%), long-term and healthy (>3 weeks) cultures of syncytiotrophoblasts are permissively infected with CMV. Greater than 99% of infectious progeny virus remained cell associated throughout culture periods up to 3 weeks. Infection of term trophoblasts required a higher virus inoculum, was less efficient, and progressed more slowly than parallel infections of placental and human embryonic lung fibroblasts. Three laboratory strains (AD169, Towne, and Davis) and a clinical isolate from a congenitally infected infant all permissively infected trophoblasts, although infection efficiencies varied. The infection of first trimester syncytiotrophoblasts with strain AD169 occurred at higher frequency and progressed more rapidly than infection of term cells but less efficiently and rapidly than infection of fibroblasts. These results show that villous syncytiotrophoblasts can be permissively infected by CMV but that the infection requires high virus titers and proceeds slowly and that progeny virus remains predominantly cell associated.
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The role of Epstein-Barr virus (EBV) on the progression of human immunodeficiency virus (HIV) infection is not well defined. The objective of this prospective study was to determine the prevalence of EBV excretion and the role that EBV might have on HIV disease progression. Fifty-two homosexual males were studied, all of whom had positive EBV serology. Twenty-four of the 27 HIV-seropositive and 14 of the 25 HIV-seronegative subjects had detectable levels of EBV DNA in oropharyngeal cells. In addition to a greater prevalence of detectable EBV, the level of excretion was higher among HIV-seropositives than among HIV-seronegatives, and higher among group III than among group II HIV-seropositive men. These results are consistent with earlier studies showing a relationship between immunosuppression and EBV reactivation. The EBV excretion levels in a control group of 52 age-matched heterosexual males were substantially lower than those found in the homosexual group. In a proportional hazards regression analysis EBV excretion was found to be the best single predictor of progression of HIV infection (P less than 0.001). HIV p24 core antigenemia (P = 0.048) and low EBNA (P = 0.024) were significant predictors independent of EBV excretion. Whether EV directly accelerates the time to progression or is merely a marker of underlying subclinical immunosuppression remains an open question.
Between 1986 and 1988, 450 adults undergoing coronary artery bypass, cardiac valve replacement, or both were enrolled into a prospective, randomized, comparative trial of cephalothin versus cefamandole as perioperative prophylaxis. They were assessed during their hospitalization and at 6 weeks and 6 months after discharge for postoperative infectious complications. Eleven patients had major postoperative infections including 5 with sternal wound infections (three bacteremic), 6 with bacteremia, 1 with prosthetic valve endocarditis, and 3 with severe venous donor graft site infections. Eight major infections occurred in patients receiving cephalothin prophylaxis and three in patients receiving cefamandole, with all five sternal wound infections occurring in the cephalothin group. Postoperative pathogens responsible for the major infections included gram-negative aerobes in 5 patients, Staphylococcus aureus in 4, and Staphylococcus epidermidis in 2. Preoperative colonizing staphylococcal isolates were not predictive of postoperative staphylococcal pathogens. Although there was no statistically significant difference in rate of major postoperative infectious complications using either cephalothin or cefamandole prophylaxis, there was a trend in favor of cefamandole. Gram-negative aerobes are becoming increasingly important pathogens in this setting.
In a patient receiving sulfinpyrazone (Anturan, Geigy) an unusually high dose of cyclosporine (Cys) was required to maintain serum values in the range of 50-200 ng/ml. After eight months of 1300-1500 mg/day, the patient complained of increasing malaise and symptoms of cyclosporine side-effects. This clinical state was accompanied by splenomegaly and two monoclonal peaks in the gamma region on serum electrophoresis. Concomitantly, rising cytomegalovirus IgM titres, following by rising IgG titres, indicated a primary cytomegalovirus infection. This ominous biclonal proliferation markedly diminished during the subsequent six months, during which time the cyclosporine dose was minimised. He returned to good health, splenomegaly and monoclonal gamma globulin virtually disappearing. He remains well at 16 months post-transplantation.
Levels of IgG and IgM antibodies t human cytomegalovirus (CMV) were measured using a solid-phase radioimmunoassay. Individuals positive by complement-fixation test consistently had detectable IgG titers by radioimmunoassay, but no quantitative relationship was apparent. An elevated IgM titer was considered specific for CMV infection because sera from individuals with other herpesvirus infections did not cross-react. In patients with mononucleosis, elevated titers of IgM antibody to CMV correlated (P less than 0.001) with active infection and were highest during viremia. Titers of IgG antibody to CMV during and after symptomatic infection were similar to those of asymptomatic positive individuals. Increases in CMV-specific IGM were observed in both primary and reactivated infections in cardiac transplant recipients. In a small group of cardiac transplant recipients with recurrent symptomatic disease, IgM titers were low at the time of viruria and did not increase with CMV tissue involvement, a result which suggests that quantitative deficiencies in IgM may be related to the severity of CMV infections.
To assess the significance of sexual intercourse as a precipitating factor of urinary tract infection in premenopausal women with recurrent infection, 15 patients were monitored with daily dipslides and calendar recording of intercourse episodes after antimicrobial prophylaxis was discontinued. Eleven patients experienced 16 infections; 12 infections occurred within 24 hr of an intercourse episode, two occurred during the menstrual period, and two had no recognizable association. In 12 control subjects, followed in a similar fashion, three infections--all within 24 hr of an intercourse episode--were documented. There was no difference in frequency of intercourse between patients and controls, but the frequency was higher in infected women than in uninfected women (P less than 0.02). These data suggest that in sexually active women, most urinary tract infections are intercourse-related.