Modification of exercise-aggravated coxsackievirus B3 murine myocarditis by T lymphocyte suppression in an inbred model.

The effects of T lymphocyte suppression on coxsackievirus B3 (CB3) myocarditis and its augmentation by exercise were determined in this study. Three-week-old male C3H/HeN mice were divided into four groups. Group 1 mice were infected intraperitoneally (IP) on day 0 with CB3 10(2.5) TCID50, were made to swim daily from days 1 to 9, and were immunosuppressed with daily doses of cyclosporine A (25 mg/kg IP) from days -2 to 8, plus 0.1 ml antithymocyte 1.2 IgG 2a monoclonal antibody IP on day 0. Mice in group 2 were infected and made to swim daily from days 1 to 9. Mice in group 3 were infected and immunosuppressed as outlined. Mice in group 4 were infected IP with CB3. Mortality rates during the acute phase of infection (days 1 to 9) were as follows: group 1, 4% (1/25); group 2, 52% (13/25); groups 3 and 4, 0. Overall mortality rates through day 21 were as follows: group 1, 67% (17/25); group 2, 72% (18/25); group 3, 40% (10/25); and group 4, 4% (1/25). Mean viral titers in serum were highest in the immunosuppressed groups throughout the study. Myocardial viral titers (mean log10 TCID50) were higher in group 2 mice than in group 1 on days 6 (10(6.9) vs 10(4.6)) and 9 (10(8.4) vs 10(7)); however, these titers peaked in group 1 mice on day 13 (10(9.7)). Myocardial inflammation, necrosis, and mean heart weight/body weight ratios were lower in group 1 compared with group 2 on days 6 and 9 but were maximal on day 13 in group 1. Neutralizing antibody titers were lower in immunosuppressed mice on days 6 and 9; however, a rebound increase occurred on day 13.(ABSTRACT TRUNCATED AT 250 WORDS)

Vancomycin during pregnancy: does it cause hearing loss or nephrotoxicity in the infant?

Vancomycin was administered intravenously to 10 pregnant women for the treatment of methicillin-resistant Staphylococcus aureus infections. Auditory brainstem response testing and renal function studies were performed on the 10 babies in the experimental group and 10 babies in each of two control groups to determine the safety of vancomycin use during pregnancy. Auditory brainstem responses were not normal at birth in six infants from the three different groups studied (N = 30) but were normal at 3 months in five. The sixth infant had conductive hearing loss unrelated to vancomycin use that spontaneously disappeared at 12 months of age. Renal function was normal in all infants. Vancomycin was detected in cord blood in two patients and in breast milk in one. Adequate serum levels were achieved with routine doses in eight mothers tested; no adverse reactions occurred. It appears that vancomycin use during the second and third trimesters of pregnancy does not produce sensorineural hearing loss or nephrotoxicity in the infant.