Binding of peptides with basic residues to membranes containing acidic phospholipids

There are clusters of basic amino acids on many cytoplasmic proteins that bind transiently to membranes (e.g., protein kinase C) as well as on the cytoplasmic domain of many intrinsic membrane proteins (e.g., glycophorin). To explore the possibility that these basic residues bind electrostatically to monovalent acidic lipids, we studied the binding of the peptides Lysn and Argn (n = 1-5) to bilayer membranes containing phosphatidylserine (PS) or phosphatidylglycerol (PG). We made electrophoretic mobility measurements using multilamellar vesicles, fluorescence and equilibrium binding measurements using large unilamellar vesicles, and surface potential measurements using monolayers. None of the peptides bound to vesicles formed from the zwitterionic lipid phosphatidylcholine (PC) but all bound to vesicles formed from PC/PS or PC/PG mixtures. None of the peptides exhibited specificity between PS and PG. Each lysine residue that was added to Lys2 decreased by one order of magnitude the concentration of peptide required to reverse the charge on the vesicle; equivalently it increased by one order of magnitude the binding affinity of the peptides for the PS vesicles. The simplest explanation is that each added lysine binds independently to a separate PS with a microscopic association constant of 10 M-1 or a free energy of approximately 1.4 kcal/mol. Similar, but not identical, results were obtained with the Argn peptides. A simple theoretical model combines the Gouy-Chapman theory (which accounts for the nonspecific electrostatic accumulation of the peptides in the aqueous diffuse double layer adjacent to the membrane) with mass action equations (which account for the binding of the peptides to greater than 1 PS). This model can account qualitatively for the dependence of binding on both the number of basic residues in the peptides and the mole fraction of PS in the membrane.

[Protective effect of Glycyrrhiza uralensis Fisch and its extracts on the chronic desensitization of beta-adrenoceptors in guinea pigs]

Histamine-induced wheezing test is conjunction with radioligand binding assay showed that after long-term administration of isoprenaline the reactivity and R, value (total receptor binding sites) of beta-adrenoceptors in the lung tissue of guinea pigs were reduced. The decoction of Glycyrrhiza uralensis Fisch or its extractive LX56 given intraperitoneally could prevent these changes, but the decoction per os or glycyrrhetinic acid given intraperitoneally could not.

[Autologous mixed lymphoma reaction in patients with malignant lymphoma]

Human T cells can be induced to proliferate in vitro when they are cocultured with autologous Non-T cells. This phenomenon has been termed the autologous mixed lymphocyte reaction, AMLR. In this study, AMLR was assessed in 14 untreated patients with lymphoma and 13 age-and-sex-matched healthy controls. This difference was significant (P less than 0.001), suggesting that patients with lymphoma may have impaired AMLR.

The three-dimensional structure of canine parvovirus and its functional implications

The three-dimensional atomic structure of a single-stranded DNA virus has been determined. Infectious virions of canine parvovirus contain 60 protein subunits that are predominantly VP-2. The central structural motif of VP-2 has the same topology (an eight-stranded antiparallel beta barrel) as has been found in many other icosahedral viruses but represents only about one-third of the capsid protein. There is a 22 angstrom (A) long protrusion on the threefold axes, a 15 A deep canyon circulating about each of the five cylindrical structures at the fivefold axes, and a 15 A deep depression at the twofold axes. By analogy with rhinoviruses, the canyon may be the site of receptor attachment. Residues related to the antigenic properties of the virus are found on the threefold protrusions. Some of the amino termini of VP-2 run to the exterior in full but not empty virions, which is consistent with the observation that some VP-2 polypeptides in full particles can be cleaved by trypsin. Eleven nucleotides are seen in each of 60 symmetry-related pockets on the interior surface of the capsid and together account for 13 percent of the genome.

Schistosoma japonicum: some parameters affecting the development of protective immunity induced by a cryopreserved, irradiated schistosomula vaccine in guinea-pigs

Experiments were conducted in guinea-pigs to elucidate the parameters affecting the development of protective immunity against Schistosoma japonicum induced by a cryopreserved, irradiated schistosomula vaccine such as the number of immunizations, route of injection and the use of adjuvants. Results obtained indicated that the cryopreserved, irradiated schistosomula vaccine was effective by either intradermal or intramuscular injection. One intradermal injection with BCG adjuvant resulted in an average worm reduction of 50 x 24%, only a little lower than that of a non-cryopreserved, irradiated vaccine, 53 x 55%, with no statistically significant difference between the two. By intramuscular injection the worm reduction was lower (max. 40%) whether given with or without adjuvants or in 1 or 2 injections.

Regulation of calcium-activated potassium efflux by neurotensin and other agents in HT-29 cells

Neurotensin receptors have been shown previously to be coupled to polyphosphoinositide turnover and intracellular Ca2+ ([Ca2+]i) mobilization in HT-29 colonic epithelial cells (Bozou et al. Biochem. J. 264: 871, 1989; Turner et al. J. Pharmacol. Exp. Ther. 253: 1049, 1990). In this study, neurotensin was found to enhance dramatically the Ba2(+)- and tetraethylammonium chloride-sensitive K(+)-efflux rate (measured with 86Rb+) in the presence of ouabain and bumetanide, with basal efflux increasing 4.5 +/- 0.5-fold with 10 nM neurotensin. The K(+)-efflux rate, which was partially dependent on the extracellular Ca2+ concentration, was also increased by carbachol and ATP, two other [Ca2+]i-mobilizing agonists in HT-29 cells, as well as by the Ca2+ ionophores ionomycin and A23187, suggesting that the efflux was through Ca2(+)-activated K+ channels. Pretreatment of cells with neurotensin, carbachol, or ATP desensitized subsequent neurotensin-stimulated efflux by 82, 57, and 63%, respectively, confirming our previous results which indicated homologous and heterologous desensitization of the neurotensin receptor-signal transduction pathway. Pretreatment of cells with the protein kinase C activators phorbol 12-myristate 13-acetate (PMA) and mezerein did not affect [Ca2+]i mobilization or K+ efflux directly but desensitized neurotensin-stimulated efflux by greater than 80%. Pretreatment (2 h) with PMA also decreased K+ efflux in response to ionomycin by 59%, although ionomycin-induced [Ca2+]i mobilization was not inhibited. Downregulation of protein kinase C by overnight pretreatment with PMA resulted in recovery of ionomycin-stimulated efflux. These results suggest that agonist-stimulated Ca2(+)-activated K+ channels in HT-29 cells are regulated at multiple steps in the signal transduction pathway.

Murine acute retinal necrosis

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Crystallization of cauliflower mosaic virus

Cauliflower mosaic virus has been crystallized in hanging and sitting drops. The hexagonal and octahedrally shaped crystals are up to 0.5 mm in mean diameter. The octahedrally shaped crystals diffract to about 27 A resolution. The results are discussed in relation to the lability and aggregation of the virions.

Coated amperometric electrode arrays for multicomponent analysis

This paper describes a sensor array of several amperometric electrodes, each coated with a different permselective film. Coatings with different transport properties, based on size (cellulose acetate), charge (Nafion, poly(vinylpyridine), poly(ester sulfonic acid], and polarity (phospholipid) are employed in connection with a four-electrode thin-layer flow detector. With equipotential operation, the array's response pattern of each analyte provides a unique characterization of the individual components. Multicomponent analysis is obtained by taking advantage of the partial selectivity of the individual sensors and using a pattern recognition (multiple linear regression) method. Additional information is obtained by recording the complete hydrodynamic voltammogram at the individual sensors. The merits of the new array are illustrated for the quantification of neurologically significant catechol compounds.

[Gluco, lipometabolic and trace elements alteration in bile with acute purulent cholangitis]

Analysis was made of the gluco, lipometabolic materials and trace elements in bile from patients. The specimens were collected in 11 cases with acute purulent cholangitis and 13 cases of selective biliary surgery at both inter-operational time, at which the bile were got by needling from the common bile duct, and post-operational time, at which the bile was obtained from T tube drainage bile before the extraction of the T tube or discharge from hospital. It was found that lactic acid and glucose markedly decreased and LDH activity increased in the cholangitis group at inter-operational time. Lifted hepatic glyconeogenesis and gluco-consumption and hepatic cellular damage were indicated. At the same time, most of the lipo-materials and lipase activity increased, as compared with the selective group, which showed that lipolysis was encouraged and that lipo-materials had flowed into the bile because of hepatic cellular damage. At the time of acute cholangitis, the Zn and Fe in bile markedly increased but the Cr in bile decreased, and the mechanism was not clear.

Generation of collagenase-resistant collagen by site-directed mutagenesis of murine pro alpha 1(I) collagen gene

Collagenase (matrix metalloproteinase 1) cleaves type I, II, and III collagen helices at a specific site between Gly-Ile or Gly-Leu bonds (residues 775 and 776, P1-P1'). To understand the mechanism of collagen processing, mutations around the cleavage site have been introduced into the cloned murine pro alpha 1(I) collagen (Col1a1) gene. These mutant constructs have been transfected into homozygous Mov13 fibroblasts that do not express the endogenous Col1a1 gene due to a retroviral insertion. Secreted triple-helical type I collagens containing substitutions of Pro for Ile (position 776) (P1') were not cleaved by human rheumatoid synovial collagenase, whereas those containing substitutions of Met for Ile (position 776) were cleaved. Type I collagens containing double substitutions of Pro for Gln-774 (P2) and Ala-777 (P2') were not cleaved regardless of whether they contained the wild-type residue Ile at position 776 or the substitution of Met for Ile at position 776. The wild-type alpha 2(I) chains derived from the endogenous Col1a2 gene were also resistant to enzyme digestion when they were complexed with the mutant alpha 1(I) chains, indicating that the presence of normal alpha 1(I) sequences is critical for cleavage of the alpha 2(I) chains in the type I heterotrimer.

Inhibition of in vitro transcription by specific double-stranded oligodeoxyribonucleotides

A potential new therapeutic approach to control gene expression is the use of double-stranded (ds) oligodeoxyribonucleotides (oligos) to compete for the binding of nuclear factors to specific promoter and enhancer elements. As a model, we have tested the effect of oligo length, sequence and number of nuclear factor binding sites on in vitro transcription of adenovirus (Ad)E1b. Short ds oligos containing an SP1-binding sequence (sp1) inhibited transcription of E1b by more than 90%. Oligos containing multiple sp1 sequences were more effective inhibitors than would be expected for a comparable number of unlinked sp1 sites. A ds oligo with phosphorothioate (PS) linkages inhibited transcription at one-tenth the concentration needed for its normal homologue. An oligo with sp1 and a consensus TATA site was no more effective than one with sp1 alone. The stability of the PS-linked oligos will allow testing of this approach in vivo if they are adequately incorporated into whole cells.

[Ultrastructures of the capsule and subcapsular epithelium of the senile cataractous lens]

The capsule and subcapsular epithelium of 18 senile cataractous lenses and 2 normal lenses were studied by scanning and transmission electron microscopy. The structures of the capsule and subcapsular epithelium in most senile cataractous lenses were similar to those in the normal lenses. Low electron density bands composed of tiny granular or fibrillar material deep in the posterior capsule were observed in 4 of the senile cataractous lenses. Degeneration was more marked in the subcapsular epithelial cells in some of the senile cataractous lenses.

[Effect of dry ginger and roasted ginger on experimental gastric ulcers in rats]

This paper reports the effect of dry ginger and roasted ginger decoctions on four experimental gastric ulcer models in rats at an oral administration of 4.5 g/kg. The result shows that the roasted ginger has an obvious inhibiting tendency on three gastric ulcer models except the indomethacin induced model while the dry ginger has no such effects. The acute toxicity test has shown that the LD50 of roasted ginger decoction administered orally is 170.6 +/- 1.1 g/kg, but it is over 250 g/kg with dry ginger. This suggests that the water soluble constituents of the dry ginger have changed in the roasting process.

Human-mouse interspecies collagen I heterotrimer is functional during embryonic development of Mov13 mutant mouse embryos

To investigate whether the human pro alpha 1(I) collagen chain could form an in vivo functional interspecies heterotrimer with the mouse pro alpha 2(I) collagen chain, we introduced the human COL1A1 gene into Mov13 mice which have a functional deletion of the endogenous COL1A1 gene. Transgenic mouse strains (HucI and HucII) carrying the human COL1A1 gene were first generated by microinjecting the COL1A1 gene into wild-type mouse embryos. Genetic evidence indicated that the transgene in the HucI strain was closely linked to the endogenous mouse COL1A1 gene and was X linked in the HucII transgenic strain. Northern (RNA) blot and S1 protection analyses showed that the transgene was expressed in the appropriate tissue-specific manner and as efficiently as the endogenous COL1A1 gene. HucII mice were crossed with Mov13 mice to transfer the human transgene into the mutant strain. Whereas homozygous Mov13 embryos die between days 13 and 14 of gestation, the presence of the transgene permitted apparently normal development of the mutant embryos to birth. This indicated that the mouse-human interspecies collagen I heterotrimer was functional in the animal. The rescue was, however, only partial, as all homozygotes died within 36 h after delivery, with signs of internal bleeding. This could have been due to a functional defect in the interspecies hybrid collagen. Extensive analysis failed to reveal any biochemical or morphological abnormalities of the collagen I molecules in Mov13-HucII embryos. This may indicate that there was a subtle functional defect of the interspecies hybrid protein which was not revealed by our analysis or that another gene has been mutated by the retroviral insertion in the Mov13 mutant strain.

A study on the life-cycle and epidemiology of Pseudanoplocephala crawfordi Baylis, 1927

A study of the life-cycle and epidemiology of Pseudanoplocephala crawfordi Baylis, 1927 is reported. Intermediate hosts are Tenebrio obscurus, T. molitor, Carpophilus dimidiatus and Tribolium castaneum. The first three species are new host records. Development in the intermediate host takes 1-1.5 months. The completion of the life-cycle takes 2-2.5 months. Surveys of intermediate hosts, pigs, humans and rats were carried out. In Rattus norvegicus, the prevalence was as high as 22%. Epidemiological factors and suggestions for control measures are discussed.

[The role of hemorheologic changes in the pathogenesis of acute hemorrhagic necrotizing pancreatitis]

The hemorheologic alterations were studied in experimental acute hemorrhagic necrotizing pancreatitis (AHNP) which was induced by injection of 5% sodium taurocholate into the main pancreatic duct. The results showed that during the early stage of AHNP, all of hemorheologic parameters were significantly elevated, and continually increased at the rest intervals. The authors suggested that the blood viscosity and hematocrit increase, red blood cells tend to aggregate, and erythrocyte deformation decrease are the causation of pancreatic microcirculatory disturbances and promoting pancreatic progressive necrosis. After using low molecular dextran and Salvia miltiorrhizae, the hemorheologic alterations in AHNP were recovered, and the histologic observation improved. Our data indicate the hemorheologic disturbances is one of the key factors in the pathogenesis of AHNP.

"Dry lithotripsy" by a simple modification of the Chinese lithotripter KDE-1

We report on the improved technique upon a water bath lithotripter. With a simple water balloon device added to the Chinese KDE-1 Type water bath lithotripter, an extracorporeal shock wave dry lithotripter has been developed. From June to December 1988, there were 300 cases of upper urinary tract calculi and gallbladder stone treated with this machine with excellent results and no severe complications. The improved technique would be made reference to change old water bath machines into dry (water balloon) machines.