Free and polymerized tubulin in cultured bone cells and Chinese hamster ovary cells: the influence of cold and hormones

A low pH method of liposome-membrane fusion (Schneider et al., 1980, Proc. Natl. Acad. Sci. U. S. A. 77:442) was used to enrich the mitochondrial inner membrane lipid bilayer 30-700% with exogenous phospholipid and cholesterol. By varying the phospholipid-to- cholesterol ratio of the liposomes it was possible to incorporate specific amounts of cholesterol (up to 44 mol %) into the inner membrane bilayer in a controlled fashion. The membrane surface area increased proportionally to the increase in total membrane bilayer lipid. Inner membrane enriched with phospholipid only, or with phospholipid plus cholesterol up to 20 mol %, showed randomly distributed intramembrane particles (integral proteins) in the membrane plane, and the average distance between intramembrane particles increased proportionally to the amount of newly incorporated lipid. Membranes containing between 20 and 27 mol % cholesterol exhibited small clusters of intramembrane particles while cholesterol contents above 27 mol % resulted in larger aggregations of intramembrane particles. In phospholipid-enriched membranes with randomly dispersed intramembrane particles, electron transfer activities from NADH- and succinate-dehydrogenase to cytochrome c decreased proportionally to the increase in distance between the particles. In contrast, these electron- transfer activities increased with decreasing distances between intramembrane particles brought about by cholesterol incorporation. These results indicate that (a) catalytically interacting redox components in the mitochondrial inner membrane such as the dehydrogenase complexes, ubiquinone, and heme proteins are independent, laterally diffusible components; (b) the average distance between these redox components is effected by the available surface area of the membrane lipid bilayer; and (c) the distance over which redox components diffuse before collision and electron transfer mediates the rate of such transfer.     

Intraspinal Tumors in Children

Thirty cases of intraspinal neoplasms occurring during the first two decades of life are reviewed. Histologic examination showed 13 of these to be astrocytomas, 6 neuroblastomas, 5 sarcomas, 3 ependymomas, 2 neurofibromas and 1 a schwannoma. Orthopedic deformities developed or worsened in 60 percent of patients surviving longer than a year after diagnosis. In five patients some form of endocrine deficiency developed after irradiation. For treatment of radiosensitive extradural malignant lesions, biopsy followed by irradiation is advocated.     

Survival of Vibrio anguillarum and Vibrio salmonicida at different salinities

The fish pathogenic bacteria Vibrio anguillarum and V. salmonicida showed the capacity to survive for more than 50 and 14 months, respectively, in seawater microcosms. A salinity of 5% proved lethal to V. anguillarum harvested in the late-exponential growth phase, whereas a salinity of 9% was lethal to the bacterium after it had been starved at a salinity of 30% for 67 days. The lethal salinity for V. salmonicida harvested in the late-exponential growth phase was probably in the vicinity of 10%. V. anguillarum and V. salmonicida were very sensitive to nalidixic acid. Direct determination of viable cells after incubation with nalidixic acid was not possible, since the cells did not elongate. Samples of V. salmonicida were double stained with fluorescein isothiocyanate-labeled antibodies and 4',6-diamidino-2-phenylindole. After 3 or 4 days of starvation, there was a discrepancy between the total numbers of cells as determined by immunofluorescence versus by staining with 4',6-diamidino-2-phenylindole. The immunofluorescence counts remained high, which indicated the presence of intact cell envelopes but leakage of DNA and other cytoplasm components. After 2 weeks of starvation, for some of the cells, the region stained with 4',6-diamidino-2-phenylindole (i.e., DNA) was markedly smaller than the cell envelope. I attributed this to a shrinkage of the cytoplasm or a confined nucleoid or both. V. anguillarum lost its exoproteolytic activity before 11 days of starvation.     

ESR and ENDOR of primary reactants in photosynthesis

The primary reactants in photosynthesis are defined as the chemical entities on which charges are generated and stabilized after capture of a photon by the photochemical trap: PIX ^hv P ^* IX P ⁺ I ^– X P ⁺ IX ^–, where P stands for the primary electron donor, P ^* for its excited singlet state, I for the first (ESR-detectable) electron acceptor and X for the secondary acceptor complex. The ESR and ENDOR experiments which have played a rÔle in the identification and characterization of P, I, and X in the bacterial and plant photosystems are comprehensively reviewed. The structural and kinetic information obtained with magnetic resonance techniques are integrated with results obtained with optical spectroscopy to give a unified picture of the pathway of primary photochemistry in photosynthesis. Nomenclature of Primary Reactants In the interest of uniformity this review introduces a nomenclature of the primary reactants that deviates in some respects from the commonly used labels. The nametags used here and listed below are abbreviations of the molecules that are identified as primary reactants, with the exception of the donors, for which I have retained the commonly accepted designation. Photosystems: PS 1, photosystem 1 of plants; PS 2, photosystem 2 of plants; pBPS, the photosystem of purple bacteria; gBPS, ditto of green bacteria. P: Primary donors: P700 (PS 1), P680 (PS 2), P860 (generic label for BChl a containing purple bacteria), P960 (generic label for BChl b containing purple bacteria), P840 (generic name for green bacteria). I: First acceptors: Chl a (PS 1), Ph a (PS 2), BPh a,b (pBPS). X: Secondary acceptors: F _x (PS 1), pQ ₁ (PS 2), uQ ₁ or mQ ₁ (pBPS), B (gBPS). Tertiary acceptors: F _A,B (PS 1), pQ ₂ (PS 2), uQ ₂ (pBPS), F ₁ (gBPS).This paper is based on a lecture given at the Joint Meeting of the Belgium, German (FRG), and Netherlands Societies for Biophysics, Aachen 1980     

Value of 1-alpha-hydroxy vitamin D3 in treatment of primary hyperparathyroidism before parathyroidectomy.

The postoperative course of six patients with primary hyperparathyroidism and obvious radiological evidence of bone disease pretreated with 1-alpha-hydroxy vitamin D3 (1 alpha HCC) was indistinguishable from that of six patients with a similar clinical and radiological picture who were not pretreated. 1alphaHCC may increase the hypercalcaemia in some cases and cannot be recommended for the routine preparation of such patients for surgery.     

Local cold exposure of Andean Indians during normal and simulated activities.

Thermal resonses of Andean Indians were measured during several customary tasks associated with cold exposure in the highlands of southern Peru. These included surface temperature measurements of women while they washed clothing in the river and similar measurements of men while they constructed a diversion channel in the same river. A third test measured the effects of alcohol consumption on body temperatures during light activity. Women maintained slightly warmer hand than foot temperatures. Men maintained nearly equal hand and foot temperatures during the exposure period. Among male subjects the foot rewarmed at a faster rate than the hand. The results from the field studies compared favorably with results from earlier laboratory exposure tests. Comparisons between the river water exposure tests for males and females showed a consistent pattern where females maintained warmer hand and foot temperatures than males. These findings were in accord with previous laboratory studies among Quechua Indians and with the findings reported for other ethnic groups who experience natural cold stress. Alcohol ingestion appeared to have minimal effect in mitigating cold stress response during light activity. This finding was counter to earlier laboratory tests of resting subjects.     

Enantiopure derivatives of 1,2-alkanediols: substrate requirements of lipase B from Candida antarctica

Efficient methods for kinetic resolution of 1-phenoxy-2-butanol, 1-phenylmethoxy-2-butanol, and 1-phenoxy-2-pentanol were developed using lipase B from Candida antarctica as catalyst. Resolutions were performed in order to investigate the substrate requirements needed to obtain a high E-value. The effect of the substrate structure on E is different for transesterifications in organic media as compared to hydrolysis. The influence of different acyl donors on the E-value was also investigated.     

A Natural Combination Extract of Viscum album L. Containing Both Triterpene Acids and Lectins Is Highly Effective against AML In Vivo

Aqueous Viscum album L. extracts are widely used in complementary cancer medicine. Hydrophobic triterpene acids also possess anti-cancer properties, but due to their low solubility they do not occur in significant amounts in aqueous extracts. Using cyclodextrins we solubilised mistletoe triterpenes (mainly oleanolic acid) and investigated the effect of a mistletoe whole plant extract on human acute myeloid leukaemia cells in vitro, ex vivo and in vivo. Single Viscum album L. extracts containing only solubilised triterpene acids (TT) or lectins (viscum) inhibited cell proliferation and induced apoptosis in a dose-dependent manner in vitro and ex vivo. The combination of viscum and TT extracts (viscumTT) enhanced the induction of apoptosis synergistically. The experiments demonstrated that all three extracts are able to induce apoptosis via caspase-8 and -9 dependent pathways with down-regulation of members of the inhibitor of apoptosis and Bcl-2 families of proteins. Finally, the acute myeloid leukaemia mouse model experiment confirmed the therapeutic effectiveness of viscumTT-treatment resulting in significant tumour weight reduction, comparable to the effect in cytarabine-treated mice. These results suggest that the combination viscumTT may have a potential therapeutic value for the treatment AML.     

Effect of intravenous eicosapentaenoic acid on cerebral blood flow, edema and brain prostaglandins in ischemic gerbils

Eicosapentaenoic acid is converted by cyclo-oxygenase to the prostacyclin, PGI₃. Consequently eicosapentaenoic acid might protect the brain from the impairment in cerebral blood flow that follows temporary cerebral artirial occlusion. We studied the effect of 90% pure eicosapentaenoic acid, given intravenously, on cerebral blood flow, brain water and prostaglandins after ischemia in gerbils. Ischemia was produced by bilateral carotid occlusion for 15 min followed by reperfusion for 2 h. In experimental gerbils, 0.833 mg or 0.167 mg of eicosapentaenoic acid (Na salt) was given intravenously followed by a continuous infusion of 1 mg h⁻¹. Control gerbils were given 0.167 mg of linoleic acid (Na salt) intravenously followed by a continuous infusion of 1 mg h⁻¹ or a saline infusion. Regional cerebral blood flow was measured by the hydrogen clearance method and brain water by the specific gravity technique. Brain diene prostaglandins were measured by radioimmunoassay. In control gerbils cerebral blood flow decreased significantly during reperfusion and remained depressed after 2 h of reperfusion. In eicosapentaenoic acid treated gerbils blood flow decreased initially but after 2 h of reperfusion blood flow was significantly higher than in control gerbils. Brain edema and brain diene prostaglandins were not significantly different between control and experimental groups.Our study indicates that eicosapentaenoic acid, given intravenously, improves cerebral blood flow after ischemia and reperfusion. We speculate that this effect may be due to the formation of the prostacyclin, PGI₃.