Sea-blue histiocytosis and beta-thalassemia in the same family.

Among 5 families with SBH of Neapolitan origin, herediatry glyco-lipidosis was accompanied in one by beta-thalassemia. All 10 members of this family, namely parents and 8 siblings, were investigated. The mother and two children were found to be carriers of both SBH and beta-thalassemia, while three other siblings were carriers of SBH alone. None of the six patients conformed the classic clinical picture often observed in genotypical SBH. The present state of genotypic transmission of the stigma is discussed on the basis of the author's experience as well as the data in the literature. As for the combination SBH-thalassemia in the same individual it may be concluded that the two genes are most likely independent and certainly not linked.     

Xanthones from Tovomita pyrifolium

The wood of Tovomita pyrifolium (Guttiferae) contains the novel tovopyrifolins A [1,6-dihydroxy-7-methoxy-5-prenyl-6′,6′-dimethylpyrano (2′,3′:3,2)xanthone], B (1,5-dihydroxy-3,4-dimethoxyxanthone) and C (1,3,5-trihydroxy-2-methoxyxanthone) and also the known tovophyllins A and B [structure revised to 1,6-dihydroxy-5-prenyl-6′, 6′-dimethylpyrano(2′,3′:3,2)-6″,6″-dimethylpyrano(2″,3″:7,8)xanthone].     

Stimulatory effects of prolactin and anti-prolactin receptor serum on prolactin binding sites in rat liver cells in suspension culture

The effects of prolactin and a serum containing anti-prolactin receptor antibodies on prolactin binding sites were investigated in a suspension culture of rat liver cells. In this model, prolactin binding sites decline rapidly with time, with 90% of the sites lost at 24–48 h of culture. The inclusion of 10 to 100 nM ovine prolactin in the incubation medium, results in a 6-fold increase in prolactin binding compared to control cultures. Anti-prolactin receptor serum is capable of preventing this PRL-induced increase in its receptors. However, when incubated alone, these antibodies at lower concentrations (0.5 to 5%) mimic the up-regulatory effect of prolactin on its own binding site. These findings suggest that in rat liver cells, as has been observed for rabbit mammary gland, that the prolactin molecule is not required beyond the initial binding to its receptors for its action to be attained.     

Kinetics and dynamics of annealing during sub-gel phase formation in phospholipid bilayers: A saturation transfer electron spin resonance study

The saturation transfer electron spin resonance (STESR) spectra of spin-labeled phosphatidylcholine have been used to follow the kinetics of conversion from the gel phase to the sub-gel phase in aqueous bilayers of dipalmitoyl phosphatidylcholine. This is a simple, well-defined model system for lipid domain formation in membranes. The integrated intensity of the STESR spectrum from the chain-labeled lipid first increases and then decreases with time of incubation in the gel phase at 0°C. The first, more rapid phase of the kinetics is attributed to the conversion of germ nuclei to growth nuclei of the sub-gel phase. The increase in STESR intensity corresponds to the reduction in chain mobility of spin labels located in the gel phase at the boundaries of the growth nuclei and correlates with the increase in the diagnostic STESR line height ratios over this time range. The second, slower phase of the kinetics is attributed to growth of the domains of the sub-gel phase. The decrease in STESR intensity over this time regime corresponds to exclusion of the spin-labeled lipids from the tightly packed sub-gel phase and correlates quantitatively with calibrations of the spin label concentration dependence of the STESR intensity in the gel phase. The kinetics of formation of the sub-gel phase are consistent with the classical model for domain formation and growth. At 0°C, the half-time for conversion of germ nuclei to growth nuclei is ∼7.7 h and domain growth of the sub-gel phase is characterized by a rate constant of 0.025 h^-1. The temperature dependence of the STESR spectra from samples annealed at 0°C suggests that the subtransition takes place via dissolution of sub-gel phase domains, possibly accompanied by domain fission.     

Inhibition of HIV infection by a novel CD4 domain 2-specific monoclonal antibody. Dissecting the basis for its inhibitory effect on HIV-induced cell fusion.

HIV use the CD4 molecule as their primary cellular receptor. Residues in the N-terminal domain (D1) of CD4 are crucial to HIV attachment through the gp120 envelope component. However, other regions of CD4 appear to be required subsequently for virus- and cell-cell fusion. Little is understood of the post-binding steps which may differ between HIV variants. We report a novel anti-CD4 mAb that does not block CD4/gp120 binding, but that does efficiently block both viral infection and cell-cell syncytia formation, and define its contact site as residues in CD4 D2 using both mouse/human CD4 chimeras and CD4 substitution mutants. We also investigated the basis for its antiviral effect. Using the CD4 D2 specific mAb, we identify another conserved step in HIV infection, as evidenced by its ability to neutralize a broad range of primary isolates and T cell-line passaged strains. Monovalent forms of the mAb were used to determine if its activity was due to masking of the D2 epitope, to steric inhibition, or bivalency. Our data indicate that both binding site and bivalency of the mAb underlie its potency. The need for bivalency is not simply explained by affinity, because monovalent forms can displace the intact mAb and reverse its protective effect. These results provide evidence that binding of the D2-specific mAb prevents structural alterations necessary for membrane fusion.     

Hastifolins A–G,antifeedant neo-clerodane diterpenoids from Scutellaria hastifolia

From the aerial parts of Scutellaria hastifolia, family Lamiaceae (Labiatae), seven neo-clerodane diterpenoids (hastifolins A–G) were isolated. The products are similar to the known scuteparvin and are characterized by being trans-cinnamoyl derivatives. Structures and stereochemistry were determined by intensive NMR investigation. Six of the products form three pairs of epimers at C-13. Hastifolins A–C showed significant antifeedant activity.