Nitric oxide is produced by the NO synthase, which catalyses the conversion of arginine to citrulline and NO using tetrahydrobiopterin as an essential cofactor. N-Acetylserotonin, an inhibitor of the tetrahydrobiopterin biosynthesis, given 30 min before bacterial lipopolysaccharide to anesthetized rats, inhibited both the decrease in blood pressure and the increase in nitrite plasma levels induced by lipopolysaccharide. Thus, during endotoxemia the availability of tetrahydrobiopterin appears to be essential for the activity of NO synthase.

Amino Acid Oxidoreductases↗

PubMed1993

Ground-state configurations of the one-dimensional Falicov-Kimball model.

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Journal Article↗

PubMed1992

Exogenous nitric oxide stress on endothelial cells and macrophages.

Bovine endothelial cells (ECs, P1) and lipopolysaccharide/gamma-interferon-induced mouse macrophages (MMs) were incubated in the presence of SIN-1 and C 3754 (1 microM to 1 mM), sydnonimine metabolites of the antianginal predrugs molsidomine and pirsidomine, respectively up to 48 h. No change of the endogenous nitric oxide output from MMs and A23187- or adenosine triphosphate-stimulated ECs was found by means of the methemoglobin method. Data indicate that downregulation of the nitric oxide (NO) synthase is not obvious within the intact cells under exogenous NO stress supplied by high concentrations of the spontaneous NO donors. Cytosolic MM NO synthase extracts, however, revealed reduction in the enzymic [3H]arginine turnover to [3H]citrulline by SIN-1, but not by C 3786, the pharmacologically active metabolite of pirsidomine.

Amino Acid Oxidoreductases↗

PubMed1991

Saccharomyces cerevisiae a- and alpha-agglutinin: characterization of their molecular interaction.

An O-glycosylated protein of approximately 18 kDa responsible for mating type specific agglutination has been isolated from Saccharomyces cerevisiae a cells, purified to homogeneity and via peptide sequences the gene was cloned by PCR. An open reading frame codes for a protein of 69 amino acids. A minimum of five serine and five threonine residues of the mature protein are glycosylated. alpha-Agglutinin is a highly N-glycosylated protein of approximately 250 kDa. Both purified agglutinins form a specific 1:1 complex in vitro. Pretreatment of alpha-agglutinin, but not of alpha-agglutinin, with diethylpyrocarbonate (DEPC) prevents formation of the complex; treatment of alpha-agglutinin in the presence of alpha-agglutinin protects the former from DEPC inactivation. By carboxy terminal shortening of the alpha-agglutinin gene and by replacing three of its eight histidyl residues by arginine, the active region of alpha-agglutinin for interaction with alpha-agglutinin has been defined. Neither the N- nor the O-linked saccharides of the two agglutinins seem to be essential for their interaction.

Base Sequence↗

PubMed1990

Ground states of the spinless Falicov-Kimball model.

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Journal Article↗

PubMed1988

[Organ- and species-specific properties of glucose-6-phosphate dehydrogenase and the effect of molsidomine].

Glucose-6-phosphate dehydrogenase (G-6-PDH) is the key enzyme of the pentose phosphate cycle and therefore regulates the synthesis of the nucleic acid constituent ribose-5-phosphate. At the same time the enzyme is coupled to the synthesis of reduced glutathione (GSH) which detoxifies electrophilic molecules (radicals) in the organism. Activity and stability of G-6-PDH and the influence of SIN 1--the active metabolite of molsidomine (Corvaton)--dithiothreitol (DTT) and NADP on these parameters were studied in enzyme preparations from different organs of the rat (liver, ethmoturbinates, blood) and from blood of mouse, guinea pig, rabbit, dog and man. The highest activity of G-6-PDH was measured in rat ethmoturbinates (69.26 +/- 5.91 mU/mg protein/min), the lowest in human blood (2.99 +/- 0.18 mU/mg protein/min). G-6-PDH of rat ethmoturbinates and of rat and dog blood was unstable and nearly completely inhibited by SIN 1. The enzyme of rat liver and of human, mouse, guinea pig and rabbit blood was stable and not influenced by SIN 1. These organ-and species-specific findings are discussed with respect to the toxicological actions of SIN 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1985

A rubella outbreak among dental students: description of the outbreak and analysis of control measures.

From February to April 1982, rubella was diagnosed in 17 Washington University dental students. The affected students represented 4.8% of all dental students and 21% of susceptible students. Because a high likelihood of rubella transmission was perceived, three adjacent university hospitals undertook an emergency program to ensure immunity to rubella in all personnel. The program reached 84.6% of all target personnel, but only 36% of physicians (p less than 0.001). We estimated that the program increased the level of rubella immunity from 92.2% to 98.1%, at a total cost of $140,274 of which $29,990 was in excess of ordinary expenditures. Our experience indicates that schools training health professionals face the possibility of rubella outbreaks unless they ensure rubella immunity in all students. The experience also supports the value of ongoing programs to ensure rubella immunity in hospital personnel. Without such programs, hospitals may be forced to undertake emergency programs that are likely to be disruptive and expensive and may have relatively little immediate measurable impact.

Antibodies, Viral↗

PubMed1985

Nucleotide sequence of the G protein gene of human respiratory syncytial virus reveals an unusual type of viral membrane protein.

The major surface glycoprotein (G) of human respiratory syncytial (RS) virus has an estimated mature Mr of 84,000-90,000. Among a library of cDNA clones prepared from RS virus mRNAs, we identified clones that hybridized to a message that encoded a Mr 36,000 polypeptide that was specifically immunoprecipitated with anti-G antiserum. The amino acid sequence of the G protein backbone was determined by nucleotide sequence analysis of several of the cDNA clones. It contains a combination of structural features that make it unique among the known viral glycoproteins. The G mRNA is 918 nucleotides long and contains a single major open reading frame that encodes a polypeptide having 298 amino acid residues with a Mr of 32,587, a finding consistent with the Mr 36,000 estimate for the in vitro translation product of the G mRNA. This suggests that greater than 50% of the molecular weight of the mature glycoprotein may be contributed by carbohydrate. Glycosylation of G is largely resistant to tunicamycin, an inhibitor of the attachment of N-linked oligosaccharides, suggesting that the majority of the carbohydrate residues are attached via O-glycosidic bonds. In accordance with this, serine and threonine residues, the acceptor sites for O-linked oligosaccharides, comprise 30.6% of the total amino acid composition. There are also four potential acceptor sites for N-linked oligosaccharides. The amino acid sequence lacks both an NH2-terminal hydrophobic signal sequence and a COOH-terminal hydrophobic region. Instead, a strongly hydrophobic region is located between amino acid residues 38 and 66. This region may serve as both the signal to insert the nascent polypeptide through the membrane and as the membrane anchor site.

Amino Acid Sequence↗

PubMed1985

Respiratory syncytial virus polypeptides. IV. The oligosaccharides of the glycoproteins.

The cell-associated glycoproteins of respiratory syncytial (RS) virus included GP1 (90K), VP70 (70K), VGP48 (48K) and GP26 (26K). Although present in infected cells, there was no VP70 in purified virus. Trypsin treatment of infected cells removed 80 to 90% of VP70 as well as its products VGP48 and GP26. This suggested that most of the VP70 in the cell is located on the plasma membrane. The glycoproteins of purified RS virus (GP1, VGP48 and GP26) contain mannose, galactose and fucose as well as glucosamine, but the quantity of mannose in GP1 is low when compared to that of the other three sugars. The effects that follow the treatment of infected cells with the glycosylation inhibitors tunicamycin and monensin, and the treatment of the immunoprecipitated product of pulse-chase experiments with endonuclease H demonstrated that VP70 and its products contained N-linked oligosaccharides, and that the oligosaccharides of the mature VGP48 subunit were of the complex type, while GP1 contained both N- and O-linked oligosaccharides. The non-glycosylated forms of VP70 and GP1 have estimated mol. wt. of 50K and 33K respectively. Therefore, the carbohydrate contribution to the mol. wt. of VP70 and GP1, as determined by PAGE, was equivalent to 20K for the former and 57K for the latter. The majority of the GP1 oligosaccharides were O-linked, a form of sugar linkage not previously found among paramyxoviruses.

Asparagine↗

PubMed1985

Respiratory syncytial virus polypeptides. V. The kinetics of glycoprotein synthesis.

The cell-associated glycoproteins of respiratory syncytial virus included GP1 (90K), VP70 (70K), VGP48 (48K) and GP26 (26K). The time course of virus protein synthesis in HeLa cells revealed that the nucleocapsid protein (VPN41) was the first to appear at 11 h post-infection followed by the appearance of the other viral proteins at 16 h post-infection. Pulse-chase experiments with [3H]leucine or [35S]methionine demonstrated that the precursor for VGP48 and GP26 was an uncleaved protein of 70K (VP70) which required at least 30 min to chase into its final products, while the precursor for GP1 was a glycoprotein of 46K, and also required at least 30 min to chase into GP1. Trypsin treatment of monensin-treated infected cells suggested that VP70 can be cleaved intracellularly into its products VGP48 and GP26.

Electrophoresis, Polyacrylamide Gel↗

PubMed1983

Wound healing accelerated by Staphylococcus aureus.

While comparing the effects on wound healing of a heated scalpel with those of the cold scalpel, we discovered that inoculation of rat skin incisions with a strain of Staphylococcus aureus dramatically accelerated the gain in wound strength. The accelerating effect was evident four days postoperatively, was maximal at seven to ten days, and was still present at 28 days. The accelerating effect was correlated with the number of S aureus organisms introduced into the wound, and was found in conventional rats and rats germ free up to the time of monocontamination with S aureus. There was no evidence of infection on gross examination; on histologic examination an occasional microabscess was seen in some rats. There may be both local and systemic mechanisms underlying the S aureus accelerating effect. Seven strains of S aureus with varying characteristics demonstrated the wound-healing accelerating effect. In sharp contrast, Staphylococcus epidermidis (three strains), Staphylococcus hominis (one strain), and Pseudomonas aeruginosa (two strains) did not show this effect. The increases in wound healing due to S aureus were substantially greater than reported previously for any nutritional supplement, drug, or other chemical or physical agent.

Animals↗

PubMed1983

Respiratory syncytial virus polypeptides. III. The envelope-associated proteins.

Four proteins, GP1, VGP48, GP26 and VPM27, are associated with the envelope of respiratory syncytial (RS) virus. The status of GP1 has been uncertain, because a cellular glycoprotein migrates at the same position when Laemmli's discontinuous buffer system is used for PAGE, and because BSC-1 cells infected with the RSN-2 strain of RS virus appear not to contain GP1. However, additional evidence suggests that GP1 is a viral structural protein. (i) It is removed from cells by trypsin, while the cellular glycoprotein is not; (ii) it is separated from the cellular glycoprotein when the infected cells are analysed by neutral SDS-PAGE; (iii) it is present in the purified RSN-2 strain of RS virus produced by BSC-1 cells; (iv) it is also present in the purified Long strain of RS virus produced by either human or monkey cells. When purified Long strain virus is analysed by PAGE under non-reducing conditions, the glycoproteins VGP48 and GP26 migrate together, and VPM27 separates into two proteins, which one-dimensional peptide mapping suggests are not different proteins. These observations suggest that VGP48 and GP26 exist in the virion as a single molecule joined by disulphide bonds, and so resemble a paramyxovirus fusion protein, and that probably there are two forms of VPM27 which differ in either position or number of disulphide bonds.

Electrophoresis, Polyacrylamide Gel↗

PubMed1982

Medroxyprogesterone acetate and homozygous sickle-cell disease.

The haematological and clinical effects of medroxyprogesterone acetate in homozygous sickle-cell (SS) disease were assessed in a 2-year controlled crossover trial completed by 23 patients. Haematological indices remained steady during the placebo phase, but during the medroxyprogesterone-acetate phase fetal haemoglobin, total haemoglobin, red-cell mass, and red-cell survival rose significantly, and reticulocytes, irreversibly-sickled-cell counts, and total bilirubin fell significantly. Painful crises were significantly less frequent during the medroxyprogesterone-acetate than the placebo phase. These results are compatible with an inhibition of in-vivo sickling in patients with SS disease during medroxyprogesterone-acetate treatment. The mechanisms of such an effect require further study.

Adult↗