Metabolism and role of O-acetylated sialic acids.
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Acetylation↗
Biomedical subjects
H Schmid
Publications and source records attributed to H Schmid.
Relationship between release of nitric oxide and CO2 and their dependence on oxidation reduction potential in wastewater treatment.
Nitric oxide (NO) is an intermediate of denitrification process and can be produced by denitrifiers, nitrifiers and other bacteria. In our experiments we measured the dynamic flow of NO depending on oxidation reduction potential (ORP). Different ORP-ranges were related to various carbon loading stages in the wastewater treatment pilot plant. Nitrification and denitrification were achieved by a sequence of aeration and non-aeration periods. Our measurements show that different carbon loading conditions (low feed, balanced and overloaded conditions) did not change the range of the mixing ratio of NO emissions when the aeration conditions like air-flow and temperature were kept constant. Minimum and maximum NO mixing ratios were 34.7 and 91.8 ppbv; 52.3 and 91.3 ppbv; 57.6 and 109 ppbv for low feed, balanced and overloaded conditions, respectively. The curve of the NO graph relied on nitrification/denitrification dynamics. The dependence of NO release on different ORP and CO2-release during the various conditions are shown. Longer aeration times resulted in an increased release of gaseous NO. The net-release of NO g(-1) nitrogen removed was between 0.014% and 0.028%. The NO fluxes to the air were observed between 8.3 and 14.9 mg m(-2) d(-1) NO. The major release occurred during high aeration periods whereas the concentration of dissolved [NOaq] in the wastewater was less than 0.05% of the gaseous release due to very low solubility of the NO.
Air Pollutants↗
Increased renal GLUT1 abundance and urinary TGF-beta 1 in streptozotocin-induced diabetic rats: implications for the development of nephropathy complicating diabetes.
Increased expression of transforming growth factor beta-1 (TGF-beta 1) and glucose transporter (GLUT1) has been implicated in the genesis of diabetic nephropathy. The aim of this study was to evaluate GLUT1 protein levels in the renal cortex of a rat model of diabetes as well as its relationship to urinary albumin and TGF-beta1. Streptozotocin-injected rats (n = 13) and controls (n = 13) were compared for their urinary albumin, and TGF-beta 1 and for renal cortical and medullar GLUT1 protein abundance. GLUT1 protein content was determined by optical densitometry after Western blotting using an anti-GLUT1 antibody; urinary albumin was measured using electroimmunoassay, urinary TGF-beta 1 using ELISA. Forty-five days of diabetes resulted in increased albuminuria (p < 0.05), urinary TGF-beta 1 (p < 0.05) and GLUT1 protein abundance (p < 0.05). There was a positive correlation between urinary TGF-beta 1 and plasma glucose levels (r = 0.65, p < 0.05) and albuminuria (r = 0.72, p < 0.05). We concluded that 45 days of diabetes result in incipient diabetic nephropathy and increased cortical GLUT1 protein abundance. We speculate that the higher cortical GLUT1 protein levels in diabetes may amplify the effects of hyperglycemia in determining higher intracellular glucose in mesangial cells, thereby contributing to diabetes-related kidney damage.
Albuminuria↗
Predictors of cigarette smoking by young adults and readiness to change.
A survey on cigarette smoking of a sample of 406 students aged 16/17 years from a Swiss city was carried out in 1995, and the sample was reinvestigated in 1998. Measures were taken of gender, age, school attendance (vocational or other), negative feelings, perception of danger. parental smoking, and reasons for smoking or not smoking at Time 1. Time-2 measures included stages-of-change in smoking cessation and nicotine addiction. Negative feelings at ages 16/17 were predictive of nicotine addiction at ages 19/20, and highly predictive for starting smoking within this period. Frequent smoking and relaxation as a reason for smoking was more likely for sustained smokers than for quitters. The results suggest that if adolescents begin to smoke in order to cope with negative feelings they continue to do so and increase their smoking. Cessation can probably be promoted by advice to reduce the frequency of smoking.
Adolescent↗
Recent advances in the design and performance of research assistants.
Every laboratory needs personnel who work 24 hours a day 7 days a week, are efficient, obedient, capable of showing initiative, insightful and affable. Our experience of laboratory workers tells us that there is an immense way to go to achieve these goals. Having tired of the normal, Darwinian approach, a project has been initiated to achieve these ends through genetic technologies.
Humans↗
Systematic, immediate in-hospital initiation of lipid-lowering drugs during acute coronary events improves lipid control.
Background: Patients who have had a coronary heart attack often go completely untreated for hypercholesterolemia. We investigated whether immediate initiation of lipid-lowering drugs during hospitalization for acute coronary events increases the proportion of correctly treated patients compared to referred treatment as recommended by current guidelines. Methods: This prospective, multicenter study randomized 57 hypercholesterolemic patients hospitalized for acute coronary events to immediate in-hospital initiation or to referred initiation of lipid-lowering drugs by primary care physicians 3 months after unsuccessful nutritional intervention. Results: After 6 months, 53 patients were available for follow-up. More patients in the immediate initiation group (26/30 patients, 87%) were treated with lipid-lowering drugs than in the referred initiation-group (13/23 patients, 57%, P=0.03). Twenty-seven patients (87%) in the immediate initiation group versus 17 patients (65%) in the referred initiation group had a 10% or greater decrease in total cholesterol or a 15% or greater decrease in LDL-cholesterol (P=0.18). Although statistically not significant, there was a trend to improved lipid values in the immediate initiation group compared to the referred initiation group (TC, -21.1 vs. -13.8% (P=0.08); LDL-C, -28.2 vs. -18.9% (P=0.13); HDL-C, +10.8 vs. +5% (P=0.44); TC/HDL-C ratio, -24.7 vs. -15.1% (P=0.22)), and the LDL-C/HDL-C ratio was -34.1 vs. -19.1% (P=0.04, P=NS after Bonferroni correction). Conclusion: The immediate initiation of lipid-lowering drugs in hypercholesterolemic patients hospitalized for acute coronary events increases the rate of correctly treated patients and has the potential to improve lipid control.
Journal Article↗
Pure primary choriocarcinoma of the urinary bladder with long-term survival.
Choriocarcinoma was diagnosed in a 77-year-old woman with an acute massive, painless hematuria. One year after anterior pelvic exenteration and ileal conduit, the beta-human chorionic gonadotropin level increased to 934 mIU/mL without any sign of tumor progression. After six courses of chemotherapy (vincristine, actinomycin, and cyclophosphamide), the beta-human chorionic gonadotropin levels returned to normal. To our knowledge, this is the fourth case of pure choriocarcinoma in the bladder, with the longest survival time of 33 months so far.
Aged↗
[Accidental morbidity in adolescence: a retrospective study in 12 to 15 year-old school children in Switzerland] .
Mortality and morbidity from injuries in the adolescent population is substantial in Switzerland as all over the world. The estimation of morbidity from injuries is difficult and depends on the design of the study. Little information is available on morbidity between ages 12 and 15. The Health Behaviour in School-Aged Children (HBSC) study is an international survey based on a self-administered questionnaire for which the Swiss Institute for Prevention of Alcohol and Drug Problems (SIPA) is responsible in Switzerland. 7196 schoolchildren aged 12 to 15 participated in the 1998 survey. Questions covered subjects such as health and health behaviour. A few questions covered injuries, with reference to frequency, context and consequences. 45.3% of adolescents have been treated at least once by a nurse or a doctor for an injury during the past 12 months. It can be deduced that nearly 149,000 adolescents aged between 12 and 15 are injured in more than 260,000 accidents in Switzerland. The rate of injury is 793 per 1000 adolescents per year. Furthermore, one adolescent out of ten injures himself three times or more per year. In conclusion, morbidity due to injuries in adolescents aged 12 to 15 in Switzerland is therefore considerable. This study demonstrates the high prevalence of repeated injuries in adolescents.
Accidents↗
Validation of a capillary electrophoresis method for determination of 5-aminolevulinic acid and degradation products.
A capillary electrophoresis method was developed for simultaneous quantification of 5-aminolevulinic acid (ALA) and its degradation products 2,5-dicarboxyethyl-3,6-dihydropyrazine and 2,5-dicarboxyethylpyrazine in aqueous solution within a total analysis time of 9 min. The optimized method was validated with respect to specificity, precision, linearity, limits of detection and quantitation, and robustness. The degradation products were quantified with respect to the ALA peak. A related micellar electrokinetic chromatography method, involving the addition of sodium dodecylsulfate to the running buffer solution, was applied for direct injection of an oil-in-water emulsion containing ALA, i.e. without sample pretreatment.
Aminolevulinic Acid↗
A method for the chemical generation of N-terminal peptide sequence tags for rapid protein identification.
We describe a method for generating multiple small sequences from the N terminal of peptides in unseparated protein digests by stepwise thioacetylation and acid cleavage. The mass differences between a series of N-terminally degraded peptides give short sequences of defined length. Such short "sequence tags" together with the mass of the parent peptide can be used to identify the protein in a database. The sequence ladders are generated without the use of chain terminators or sample aliquoting and the degradation reagents are water soluble so that the chemistry can be carried out on peptides immobilized on C-18 reversed-phase supports without any peptide loss due to washing with organic solvents as occurs in Edman type sequencing. The entire procedure can be automated, and we describe a prototype device for the parallel analysis of multiple samples. We demonstrate the effectiveness of this chemical tagging method in a comparison with Edman sequencing, peptide mass fingerprinting, and MS/MS analysis of crude protein fractions obtained from an HPLC separation of the Escherichia coli ribosome complex which consists of 57 proteins. We show that chemical tagging is a viable first-pass high-throughput identification method to be used prior to an in depth MS/MS analysis.
Amino Acid Sequence↗
Degradation mechanism and stability of 5-aminolevulinic acid.
The physiological substance and precursor of the heme synthesis 5-aminolevulinic acid (ALA) is a promising prodrug for photodiagnosis and photodynamic therapy of epithelial tumors, particularly in urological and gynecological tissues. For the clinical use of this substance, a chemically stable and sterile drug formulation is required. In the present study, degradation mechanism of ALA in aqueous solution and possibilities to improve its stability were examined. A capillary electrophoretic method was developed that was suitable for the quantification of ALA and of two degradation products. The intermediate degradation product was 2, 5-dicarboxyethyl-3,6-dihydropyrazine, which was further oxidized to 2,5-dicarboxyethylpyrazine. The structures of the degradation products were proven by (1)H and (13)C nuclear magnetic resonance spectroscopy. ALA degradation was very efficiently inhibited by adjusting the pH of the aqueous solution to a value <5 and by purging with nitrogen. Additives such as antioxidants did not improve the ALA stability. These results demonstrated that low pH ALA aqueous solution may be one possible dosage form to be considered for market introduction.
Aminolevulinic Acid↗
Incidentally discovered papillary carcinoma of the thyroid: value of ultrasonographic follow-up. A case-report.
Incidentalomas of the thyroid are common small nodules found occasionally during imaging procedures. Their pathological nature is generally benign, but about 4% may harbour malignant tissue. Most current studies only suggest clinical follow-up, but there are no data about the natural history of malignant incidentalomas. The authors describe a patient with multiple incidentaloma of the thyroid submitted to fine-needle aspiration biopsy because his larger nodule grew 50% in 3 months at ultrasonographic follow-up. The cytological examination suggested thyroid malignancy in this nodule and surgical pathology showed multicentric papillary carcinoma. This case suggests that the larger diameter of a malignant incidentaloma may change rapidly. If more time had been spent before repeating the ultrasonography, the volume could have changed even more and the prognosis could have been changed as indicated by most prognostic score indexes.
Adult↗
Kynurenic acid metabolism in the brain of HIV-1 infected patients.
Patients who are infected with human immunodeficiency virus type 1 (HIV-1) frequently present with neurological and psychiatric symptoms. Kynurenic acid (KYNA), an intermediate metabolite of L-kynurenine (L-KYN), is a neuroprotectant and a broad-spectrum antagonist at excitatory amino acid (EAA) receptors. The present study examines the biosynthetic machinery of KYNA in the frontal cortex and cerebellum of 25 HIV-1 and 16 control (CO) patients. We measured the contents of L-KYN and KYNA and the activity of enzymes synthesizing KYNA, kynurenine aminotransferases I and II (KAT I and KAT II). The KYNA level was significantly increased in the frontal cortex (209 +/- 38% of CO; p < 0.05) and moderately increased in the cerebellum (164 +/- 31% of CO) of HIV-1 brains as compared with controls. The bioprecursor of KYNA, L-KYN, was increased in frontal cortex (188 +/- 45% of CO) and cerebellum (151 +/- 16% of CO; p < 0.05). The elevated KYNA in frontal cortex correlated with significant increases of KAT I (341 +/- 95% of CO; p < 0.05) and KAT II (141 +/- 8% of CO; p < 0.05). In the cerebellum, a high KYNA content was in the line with increased KAT I (262 +/- 52% of CO; p < 0.05) activity, while KAT II was in a control range (85 +/- 12% of CO). This study demonstrates that HIV-1 infection associates with elevated KYNA synthesis in the brain. In contrast to KAT II, KAT I was prominently increased in both brain regions investigated. Differences in neurochemical parameters of KYNA metabolism between frontal cortex and cerebellum suggests selective tissue damage. Drugs which influence the synthesis of the endogenous neuroprotectant KYNA may become useful in the therapy of neuropsychiatric manifestations of HIV-1 infected patients.
AIDS Dementia Complex↗
Characterisation of the enzymatic 4-O-acetylation of sialic acids in microsomes from equine submandibular glands.
Microsomes prepared from equine submandibular glands and incubated with tritium-labelled AcCoA incorporated acid-insoluble radioactivity in a manner dependent on time, protein, membrane integrity and AcCoA concentration, with incorporation being optimal at 37 degrees C and pH 6.6. Under the experimental conditions used a K(M) of 32.1 microM for AcCoA and a V(max) of 1.2 pmol/mg protein x min was obtained. The incorporation of acid-insoluble radioactivity was also inhibited by CoA in a competitive manner (K(i)=240 microM), as well as by para-chloromercuribenzoate, 3'-dephospho-CoA, 5'-IDP, 5'-ADP, beta-NAD and 4,4'-diisothiocyanatostilbene-2,2'-disulfonate. We demonstrate here that this incorporation of radioactivity into endogenous sialic acid is due to the action of an AcCoA:sialate-4-O-acetyltransferase [EC 2.3.1.44]. Radio thin-layer chromatography analyses of propionic acid-released sialic acids showed that the incorporation of radioactivity correlated with the formation of a radiolabelled species that co-migrated with authentic Neu4,5Ac2. Saponification experiments using NaOH, mouse hepatitis virus strain S and Influenza C/JJ/50 virus also showed that the transfer of [3H]acetyl groups from [3H]AcCoA to endogenous sialic acid acceptors was occurring exclusively at carbon 4 of the pyranose ring.
Acetyl Coenzyme A↗
Localization of S-adenosylhomocysteine hydrolase in the rat kidney.
S-adenosylhomocysteine (SAH) hydrolase is a cytosolic enzyme present in the kidney. Enzyme activities of SAH hydrolase were measured in the kidney in isolated glomeruli and tubules. SAH hydrolase activity was 0.62 +/- 0.02 mU/mg in the kidney, 0.32 +/- 0.03 mU/mg in the glomeruli, and 0.50 +/- 0.02 mU/mg in isolated tubules. Using immunohistochemical methods, we describe the localization of the enzyme SAH hydrolase in rat kidney with a highly specific antibody raised in rabbits against purified SAH hydrolase from bovine kidney. This antibody crossreacts to almost the same extent with the SAH hydrolase from different species such as rat, pig, and human. Using light microscopy, SAH hydrolase was visualized by the biotin-streptavidin-alkaline phosphatase immunohistochemical procedure. SAH hydrolase immunostaining was observed in glomeruli and in the epithelium of the proximal and distal tubules. The collecting ducts of the cortex and medulla were homogeneously stained. By using double immunofluorescence staining and two-channel immunofluorescence confocal laser scanning microscopy, we differentiated the glomerular cells (endothelium, mesangium, podocytes) and found intensive staining of podocytes. Our results show that the enzyme SAH hydrolase is found ubiquitously in the rat kidney. The prominent staining of SAH hydrolase in the podocytes may reflect high rates of transmethylation. (J Histochem Cytochem 48:211-218, 2000)
Adenosylhomocysteinase↗
Israel's long-term care insurance law after a decade of implementation.
Israel's Long-Term Care Insurance (LTCI) law has been in effect for a decade. It is timely to review the effects of this legislation with a view to identifying possible directions for reform and lessons for other countries considering the introduction of a similar social insurance scheme. The paper considers the law's effects in terms of the size and characteristics of the beneficiary population, the coverage of the scheme, its financial standing, the rate of institutionalization of the elderly, the caregiving burden, the service delivery system, and the overall scope of long-term care services for the aged. Israel's experience has lessons for financing arrangements, target efficiency, service delivery arrangements, and the construction of the burden of care.
Aged↗
Serine/threonine phosphorylation of calmodulin modulates its interaction with the binding domains of target enzymes.
The interaction of serine/threonine-phosphorylated calmodulin with synthetic peptides corresponding to the calmodulin-binding domains of six enzymes has been studied by fluorescence spectroscopy. For five peptides, the dissociation constant of the calmodulin-peptide complex (K(d)) increased when calmodulin was phosphorylated. An increase of more than one order of magnitude was observed with peptides derived from smooth-muscle myosin light-chain kinase and cAMP phosphodiesterase. In contrast, only a slight increase in K(d) was noted with two peptides derived from the plasma membrane Ca(2+)-ATPase and for the peptide derived from nitric oxide synthase. No significant change in affinity was detected with the peptide derived from calcineurin. In contrast, a decrease in the dissociation constant was observed with the peptide derived from the Ca(2+)-calmodulin dependent kinase II. Phosphorylation also affected the peptide-calmodulin binding stoichiometry: a decrease from two to one binding sites was observed with the peptides derived from myosin light-chain kinase and phosphodiesterase.
3',5'-Cyclic-AMP Phosphodiesterases↗
NMR solution structure of a complex of calmodulin with a binding peptide of the Ca2+ pump.
The three-dimensional structure of the complex between calmodulin (CaM) and a peptide corresponding to the N-terminal portion of the CaM-binding domain of the plasma membrane calcium pump, the peptide C20W, has been solved by heteronuclear three-dimensional nuclear magnetic resonance (NMR) spectroscopy. The structure calculation is based on a total of 1808 intramolecular NOEs and 49 intermolecular NOEs between the peptide C20W and calmodulin from heteronuclear-filtered NOESY spectra and a half-filtered experiment, respectively. Chemical shift differences between free Ca(2+)-saturated CaM and its complex with C20W as well as the structure calculation reveal that C20W binds solely to the C-terminal half of CaM. In addition, comparison of the methyl resonances of the nine assigned methionine residues of free Ca(2+)-saturated CaM with those of the CaM/C20W complex revealed a significant difference between the N-terminal and the C-terminal domain; i.e., resonances in the N-terminal domain of the complex were much more similar to those reported for free CaM in contrast to those in the C-terminal half which were significantly different not only from the resonances of free CaM but also from those reported for the CaM/M13 complex. As a consequence, the global structure of the CaM/C20W complex is unusual, i.e., different from other peptide calmodulin complexes, since we find no indication for a collapsed structure. The fine modulation in the peptide protein interface shows a number of differences to the CaM/M13 complex studied by Ikura et al. [Ikura, M., Clore, G. M., Gronenborn, A. M., Zhu, G., Klee, C. B., and Bax, A. (1992) Science 256, 632-638]. The unusual binding mode to only the C-terminal half of CaM is in agreement with the biochemical observation that the calcium pump can be activated by the C-terminal half of CaM alone [Guerini, D., Krebs, J., and Carafoli, E. (1984) J. Biol. Chem. 259, 15172-15177].
Amino Acid Sequence↗