The outcome of pregnancies complicated by bleeding during the second trimester.

Vaginal bleeding during the second trimester has historically been associated with high perinatal mortality rates (33 to 82 per cent). Because this topic has not been specifically studied since the advent of obstetric ultrasound and electronic fetal heart rate monitoring, we reviewed the experience at the University of Utah with second trimester vaginal bleeding from 1 January 1983 through 15 June 1989. The cause of the bleeding was found to fit into four general categories. These are placenta previa, abruption, both previa and abruption, and other or unknown. Midtrimester bleeding is still associated with a high perinatal mortality rate (22.3 per cent), being highest when associated with placental abruption (36.6 per cent) and lowest with placenta previa (7.4 per cent). For the entire series, pregnancies maintained into the third trimester were associated with a much lower perinatal mortality rate than those in which delivery occurred during the second trimester (7.1 versus 54.5 per cent). These relatively improved outcomes suggest that aggressive obstetric management is warranted in most instances.

Lymphokine modulation of fibroblast proliferation.

In an experimental model of interstitial nephritis resulting in fibrosis, lymphokines secreted by a common population of antigen-reactive T lymphocytes have been shown to exert a bidirectional influence on fibroblast proliferation and collagen synthesis. We report that these lymphokines can be chromatographically separated into two fractions. The larger m.w. fraction stimulated fibroblast proliferation whereas the smaller m.w. fraction was inhibitory. These results further clarify potentially important immune regulators of fibrogenesis.

Cell-mediated immunity in interstitial nephritis. IV. Anti-tubular basement membrane antibodies can function in antibody-dependent cellular cytotoxicity reactions: observations on a nephritogenic effector mechanism acting as an informational bridge between the humoral and cellular immune response.

Anti-tubular basement membrane antibodies (alpha TBMA) were tested in vitro in an antibody-dependent cellular cytotoxicity (ADCC) reaction utilizing tubular antigen-coated targets. A selected subpopulation of normal guinea pig spleen cells induced significantly more target cell lysis in the presence of sera containing alpha TBMA than in the presence of control sera. this ADCC reaction using alpha TBMA exhibited a characteristic dose responsiveness and the alpha TBMA binding was specific for species-independent tubular antigens. The spleen effector cells used in this assay were characterized as nonadherent, non-T cells bearing Fc-receptors similar to other previously described natural killer cells found in guinea pigs. These studies suggest that natural surveillance systems may be able to use alpha TBMA as an informational bridge to tubular antigens. Such a potential nephritogenic effector mechanism has not been previously described.

Microbiological metabolism of naphthyridines.

Penicillium adametzi and seven other species convert nalidixic acid, 1,4-dihydro-1-ethyl-7-methyl-4-oxo-1,8-naphthyridine-3-carboxylic acid, to 1,4-dihydro-1-ethyl-7-hydroxymethyl-4-oxo-1,8-naphthyridine-3-carboxylic acid. Forty-seven other species from six orders of fungi seem to achieve the same conversion as judged by chromatographic and spectral evidence. Under special conditions, P. adametzi also produces a second metabolite which was identified as the corresponding 7-carboxylic acid. The metabolic attack on the ring substituent is identical with the pathway previously established with humans. No evidence was obtained for metabolic attack on the naphthyridine nucleus itself.