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A 5-year-old with spastic quadraparetic cerebral palsy suffered multiple strokes after extensive orthopedic surgery. Coagulation testing was undertaken to determine whether a familial thrombophilia was present. The patient was found to be heterozygous for factor V Leiden. Factor V Leiden may be a risk factor for central nervous system events in special-needs children, particularly when common medical conditions create additional procoagulant risks.

Mutation frequency responses produced by ultraviolet light are compared in 4 closely related strains of E. coli B/r having the same tyr(Oc) allele and different excision-repair capabilities: uvr+ (excision repair initiated by wild-type UvrABC activity), uvrA (excision repair defective), uvrA/pdenV-7 (excision repair initiated by endonuclease V of bacteriophage T4, DenV activity), and uvr+/pdenV-7 (excision repair initiated by UvrABC and DenV activities). The production of Tyr+ prototrophic mutants is classified into back-mutations and de novo or converted glutamine tRNA suppressor mutations to indicate different mutation events. Cells transformed with the plasmid pdenV-7 require larger exposures than the parent strains to produce comparable mutation frequency responses, indicating that DenV activity can repair mutagenic photoproducts. When damage reduction by UvrABC or DenV is compared for each of the specific categories of mutation, the results are consistent with the idea that pyrimidine dimers infrequently or never target back-mutations of this allele, frequently target the de novo suppressor mutations, and extensively or exclusively target the converted suppressor mutations. This analysis is based on the distinction that UvrABC-initiated excision repair recognizes dimer and non-dimer (pyrimidine (6-4) pyrimidone) photoproducts but that DenV-initiated repair recognizes only pyrimidine dimers.

Several bovine spleen enzymes with acid pH optima, some of which hydrolyze bis(p-nitrophenyl)phosphate and therefore fit the definition of "phosphodiesterase IV," were partially separated by isoelectric focusing and ion-exchange techniques. The activities were characterized by zymogram analysis with the aid of p-nitrophenyl and 4-methylumbelliferyl phosphate and phosphonate substrates. A number of these enzymes meet the criteria for phosphodiesterase I or other phosphodiesterases. However, the predominant phosphodiesterase I hydrolyzes the bis(p-nitrophenyl)-and 4-methylumbelliferyl phosphates, p-nitrophenyl and 4-methylumbelliferyl phenylphosphonate, and ATP at the beta-gamma bond, but not p-nitrophenyl or 4-methylumbelliferyl 5'-thymidylate (the usual PDE I substrates). These properties, as well as the pH optimum, distinguish the activity from the previously described, alkaline pH optimum PDE I. A second phosphodiesterase hydrolyzes only the phenylphosphonates. Several other activities, less well described, are apparent on zymograms. None of the phosphodiesterases IV was also a phosphodiesterase II (no hydrolysis of 4-methylumbelliferyl 3'-thymidylate).

Mouse spleen cells sequentially agglutinated by soybean agglutinin (SBA) and peanut agglutinin (PNA) previously had been shown to be sufficiently depleted of graft-versus-host activity to allow reconstitution of lethally irradiated allogeneic recipient mice. We have now tested the extent of T-cell depletion in this cell fraction by various in vitro assays, including cytotoxicity testing with anti-Thy-1 antiserum, mitogenic response to the T-cell mitogens concanavalin A and phytohemagglutinin and allogeneic responsiveness in the mixed lymphocytes culture assay. By these criteria the SBA+, PNA+ spleen fraction, used previously in the in vivo experiments, was found to possess about 1% T-cell contamination. The slight contamination with T cells previously found in the singly agglutinated SBA fraction can be removed by a second fractionation with SBA, thus eliminating the possibility that a minor T-cell subpopulation bears receptors for SBA. Finally, we demonstrated that the twice-agglutinated fraction, by SBA and PNA or by SBA alone, contains a significant number of prothymocytes, thereby indicating that mouse prothymocytes bear receptors for both SBA and PNA. The implication of these findings to bone marrow transplantation in humans is discussed.