Alterations in apoptosis of cord and adult peripheral blood mononuclear cells induced by in vitro infection with respiratory syncytial virus

Respiratory syncytial virus (RSV), a major cause of morbidity in children, results in severe lower respiratory tract infections. With an in vitro infection system of isolated cord or adult peripheral blood mononuclear cells, addition of virus to cell cultures resulted in significant reductions in cell deaths, as measured by 2 independent assays: quantitation of cells with subdiploid levels of DNA and cells with DNA strand breaks. Decreased cell death was observed in lymphocytes and monocytes of cord and adult samples, with more dramatic effects evident in cells from cord blood. This may be linked to the increased virulence observed in infants with RSV infection. These data suggest that RSV may be equipped with some mechanism to prevent apoptosis, which is a major component of the host defense system used to eliminate virally infected cells.

Evaluation of a rapid diagnostic test for respiratory syncytial virus (RSV): potential for bedside diagnosis

OBJECTIVE

Rapid detection of respiratory syncytial virus (RSV) infection can assist clinicians in decisions regarding antiviral therapy with ribavirin as well as instituting infection control measures. The Abbott TestPack RSV is a rapid RSV detection immunoassay that can be performed on respiratory secretions in 20 to 30 minutes without special laboratory equipment. The purpose of this study was to evaluate housestaff performance of the TestPack RSV at bedside as compared with laboratory testing of aliquots of the same specimen by tissue culture inoculation, direct fluorescent antibody (DFA) testing and TestPack RSV.

METHODS

During the 1991 through 1992 RSV season, 137 nasopharyngeal aspirates or washes obtained from pediatric patients < 4 years of age suffering from acute respiratory disease were assayed by the Food and Drug Administration-approved TestPack RSV as well as conventional tube culture and DFA testing.

RESULTS

66 of 137 (48%) specimens were positive for RSV as defined by: isolation and DFA-positive (n = 48) and DFA testing positive with negative culture (n = 18); blocking assay experiments using TestPack RSV confirmed culture-negative DFA-positive specimens as positive in 8/8 instances in which material for retesting was available. Using these definitions, the sensitivity and specificity for the assays were: housestaff TestPack RSV: 92%, 93%; laboratory TestPack RSV: 97%, 98%; virus isolation: 72%, 100%.

CONCLUSION

From these data, it appears that the TestPack RSV EIA in the field setting is reliable, although laboratory confirmation of results is important.

Inactivation of respiratory syncytial virus by detergents and disinfectants

The activity of a number of detergents and disinfectants against respiratory syncytial virus (RSV) was evaluated in an in vitro assay system. Equal volumes of RSV and serial 10-fold dilutions of the test agents were mixed at 4 degrees C for 5 minutes. The RSV titer in each mixture was compared with that of untreated RSV alone. In 14 experiments with input RSV titers ranging from 2.6 x 10(3) to 2 x 10(7) plaque-forming units/ml, a 10-fold dilution of 5.25% sodium hypochlorite (generic bleach) inactivated (> or = 3-log reduction in titer) the virus. With lower RSV titers inactivation was also observed at a 100-fold dilution of bleach. Fetal calf serum concentrations up to 50% as an organic load did not diminish the bleach effect. The degree of RSV inactivation was also defined for Lysol, povidone-iodine, Amphyl, Hibiclens, Osyl, ethanol and Listermint. The short contact time, the reproducible nature of the findings and the continued effectiveness with increasing organic loads all suggest that detergents and disinfectants can potentially play an important role in decreasing the spread of RSV infection.

Methemoglobinemia from intravenous nitroglycerin: a word of caution

The dose of intravenously administered nitroglycerin (IV NTG) used to control ischemic chest pain usually is limited by hypotension from decreased preload. Herein we describe 2 patients who tolerated IV NTG without hemodynamic compromise but in whom severe impairment of blood oxygen content developed from methemoglobinemia noted during coronary bypass surgery. Methemoglobinemia must be suspected if chocolate-brown blood is encountered despite a normal arterial oxygen tension and calculated oxygen saturation. Before a methemoglobin level is available, the extent of hypoxemia can be determined by an oximetric oxygen saturation and therapy begun with intravenous administration of methylene blue. These case reports focus attention on the potential deleterious effects of undetected hypoxemia from methemoglobinemia in patients being stabilized with high-dose IV NTG for urgent cardiac surgery.

Relative incorporation of acetate and glucose into glycerides ofGlomerella cingulata

Cultures of the fungusGlomerella cingulata were pulse-labeled for 30 min with 1-(14)C-acetate at ages from 2 to 12 days old. The greatest incorporation into triglycerides and phosphoglycerides occurred in the youngest cultures, but more of the radioactive acetate was diverted to the phosphoglycerides than to the triglycerides in these cultures.In another series of experiments the incorporation of 1-(14)C-acetate or 2-(14)C-glucose into the triglycerides and phosphoglycerides of the fungus was investigated at 15-minute intervals for 1 hr. Hydrolysis of the two classes of glycerides revealed some labeling of glycerol from acetate; but, not surprisingly, acetate was incorporated into the fatty acid moieties to a greater extent than into the glycerol moieties, and there was relatively greater incorporation of 2-(14)C-glucose into glycerol than into fatty acids. Some relationships of these results to the growth and development ofG. cingulata are suggested, and implications relative to control mechanisms are pointed out.