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Biomedical subjects

M Wanke

Publications and source records attributed to M Wanke.

At least 19 recordsLinked to original sources
PubMed2001

Isoprenoid biosynthesis via 1-deoxy-D-xylulose 5-phosphate/2-C-methyl-D-erythritol 4-phosphate (DOXP/MEP) pathway.

Higher plants, several algae, bacteria, some strains of Streptomyces and possibly malaria parasite Plasmodium falciparum contain the novel, plastidic DOXP/MEP pathway for isoprenoid biosynthesis. This pathway, alternative with respect to the classical mevalonate pathway, starts with condensation of pyruvate and glyceraldehyde-3-phosphate which yields 1-deoxy-D-xylulose 5-phosphate (DOXP); the latter product can be converted to isopentenyl diphosphate (IPP) and eventually to isoprenoids or thiamine and pyridoxal. Subsequent reactions of this pathway involve transformation of DOXP to 2-C-methyl-D-erythritol 4-phosphate (MEP) which after condensation with CTP forms 4-diphosphocytidyl-2-amethyl-D-erythritol (CDP-ME). Then CDP-ME is phosphorylated to 4-diphosphocytidyl-2-amethyl-D-erythritol 2-phosphate (CDP-ME2P) and to 2-C-methyl-D-erythritol-2,4-cyclodiphosphate (ME-2,4cPP) which is the last known intermediate of the DOXP/MEP pathway. For- mation of IPP and dimethylallyl diphosphate (DMAPP) from ME-2,4cPP still requires clarification. This novel pathway appears to be involved in biosynthesis of carotenoids, phytol (side chain of chlorophylls), isoprene, mono-, di-, tetraterpenes and plastoquinone whereas the mevalonate pathway is responsible for formation of sterols, sesquiterpenes and triterpenes. Several isoprenoids were found to be of mixed origin suggesting that some exchange and/or cooperation exists between these two pathways of different biosynthetic origin. Contradictory results described below could indicate that these two pathways are operating under different physiological conditions of the cell and are dependent on the developmental state of plastids.

Animals↗
PubMed2000

Half-life of ubiquinone and plastoquinone in spinach cells.

The half-life of plastoquinone (PQ), ubiquinone-9 (UQ-9) and ubiquinone-10 (UQ-10) in spinach tissue was determined. This was achieved by monitoring the decay of radioactivity incorporated into these lipids from a labeled precursor. The half-life of PQ was 15 h while for UQ-9 and UQ-10 it was longer, i.e. 30 h. The values of half-lives of PQ and UQ suggest a high rate of turnover of these lipids in spinach cells.

Journal Article↗
PubMed2000

Subcellular localization of plastoquinone and ubiquinone synthesis in spinach cells.

In vivo labeling of spinach etiolated leaves with [(3)H]mevalonate followed by rapid cell fractionation procedure showed that ER-Golgi membranes are involved in transport of plastoquinone (PQ) and ubiquinone (UQ) to plastids and mitochondria, respectively. Translocation of these lipids was inhibited by agents which affect protein and lipid intracellular transport causing structural and functional disintegration of the ER-Golgi system (monensin, brefeldin) and interfere with mitochondrial energy conservation (carbonyl cyanide m-chlorophenylhydrazone), but was not affected by colchicine which influences the organization of the cytoskeletal network. Colchicine treatment resulted in marked stimulation of PQ and UQ synthesis. Results of experiments with pre-exposure of etiolated seedlings to light suggest that translocation processes are dependent on the plastid developmental state and their capacity as acceptors of PQ. Thus, the experiments indicate that biosynthesis and transport of PQ and UQ involve multiple cellular compartments and that kinetics of the transport process is dependent on the actual physiological conditions.

Biological Transport, Active↗
PubMed1998

[Heparin-induced thrombocytopenia with unfractionated heparin. A prospective study of inpatient treatment of internal medicine patients].

AIM: To investigate the influence of unfractionated heparin on heparin-induced thrombocytopenia (HIT) type II. PATIENTS AND METHOD: In 162 patients with internal diseases treated therapeutically of prophylactically with unfractionated heparin (heparin sodium, heparin calcium), we carried out a prospective study to determine the incidence of HIT type I and II. 55.6% of the patients were female (n = 90) with an average age of 76.5 years (range: 25 to 96 years) and 44.4% male (n = 72) with an average age of 67.5 years (range: 17 to 93 years). A platelet count was taken regularly before the start of heparin treatment, on the first day of treatment and then every second day from day 5 to 20. Whenever HIT II was suspected, an HIPA test was performed. RESULT: Type I HIT occurred in 10%, type II in 3% of the cases. Two of the 5 patients with type II developed severe thrombotic complications. CONCLUSION: In view of the high incidence of HIT, regular platelet counts should always be carried out in patients receiving heparin treatment.

Adult↗
PubMed1998

The diversity of polyprenol pattern in leaves of fruit trees belonging to Rosaceae and Cornaceae.

The polyprenol pattern in leaves of fruit trees belonging to the Rosaceae (genera: Prunus, Malus) and Cornaceae (genus: Cornus) families is presented. The content of polyprenyl acetates varied within plant species between 10-50 mg per gram of dry weight. In genus Prunus, Cornus and in representatives of species Malus domestica, a mixture of polyprenols composed of 18, 19, 20, 21 isoprene units was found. In six species of genus Prunus (sour-cherry): P. serrulata-spontanea, P. yedoensis, P. fruticosa. P. kurilensis, P. subhirtella and P. incisa the presence of a second polyprenol family, i.e. the group of prenologues consisting of prenol -35, -36, -37, etc. up to -42 was detected.

Chromatography, High Pressure Liquid↗
PubMed1997

Clinical use of dexamethasone for termination of unwanted pregnancy in dogs.

Dexamethasone was administered orally for 7.5 or 9.5 days to 80 pregnant bitches to terminate unwanted pregnancy at an outpatient clinic. Treatment was initiated at day 30-35 (n = 74) or day 45-50 (n = 6) of confirmed pregnancy using one of two dosages. In 62 bitches, dexamethasone was administered twice a day for 7.5 days increasing from 0.1 to 0.2 mg kg-1 over the first 2 days of administration and decreasing from 0.16 to 0.02 mg kg-1 over the last five administrations. The 18 remaining bitches were given dexamethasone twice a day for 9.5 days, at a dosage of 0.2 mg kg-1 for 7 days and then decreasing from 0.16 to 0.02 mg kg-1 over the last five administrations. Pregnancy was terminated without complication in 75 of the 80 bitches, and uterine contents were absorbed or aborted or both. Pregnancy was not terminated in five bitches treated for 7.5 days beginning at day 30-35 of gestation. In four of them parturition occurred at the normal time; in one, pregnancy was terminated by a second treatment. Pregnancy termination occurred at 7-15 days after the start of treatment. During ultrasonographic imaging of 13 bitches treated with dexamethasone, fetal deaths occurred between 5 and 13 days after the start of treatment. The side effects reported by the owners included polydipsia and polyuria, which were observed in all of the bitches and which disappeared when the treatment was discontinued. Some bitches also experienced vaginal discharge, restlessness, anorexia or emesis. At the first or second cycle after treatment, 20 bitches were mated and had normal pregnancies and normal litters. The results suggest that oral treatment with dexamethasone can be used to terminate pregnancy in bitches, but that in some cases the withdrawal of treatment after 8 days can result in retention of live pups and require a further treatment or the use of another abortifacient.

Abortifacient Agents, Steroidal↗
PubMed1996

Considerations for regional health authorities in the provision of environmental health services.

As population health programs, environmental health services differ fundamentally from other forms of health service delivery. At a time when the health sector is striving for integration, the incorporation of these unique services into the delivery system presents a unique challenge to policy makers and administrators across the country. The University of Alberta recently completed a comprehensive review and redesign of locally governed and delivered environmental health protection services in Alberta. This paper outlines the key issues and unique features surrounding the delivery of environmental health services and presents the study team's suggested approach to addressing these issues.

Alberta↗
PubMed1996

Toward a framework for health service research.

Fiscal concerns have provided the impetus for wide-ranging attempts to reform the delivery of health care in Canada. Health reform has in turn stimulated great interest and activity in health service research. For health service research to be of maximum use in addressing current and future challenges to the health care system, closer liaison is needed between researchers and decision makers--the users of research. The purpose of this paper is to promote greater interaction between decision makers and researchers by proposing a framework for health predicated on types of information needed for decision-making rather than on study methodologies. We distinguish between decision makers at the societal, health system, program and service levels. Types of studies are classified by their purpose and by the phase of the management cycle for which they provide information for decision-making.

Canada↗
PubMed1995

Termination of pregnancy in dogs by oral administration of dexamethasone.

Dexamethasone was administered orally for 7.5 or 10 d to each of 20 pregnant bitches beginning at an estimated 28 to 51 d of gestation, using 1 of 2 dose regimens. Five bitches were given dexamethasone 3 times a day for 10 d, with the highest dose of 0.2 mg/kg for 5 d and then at progressively decreasing doses of 0.16-0.02 mg/kg for 5 d. The 15 remaining bitches were given dexamethasone 2 times a day for 7.5 d, increasing from 0.1 to 0.2 mg/kg over the first 3 administrations, then remaining at 0.2 mg/kg on Days 2 to 5, and decreasing from 0.16 to 0.02 mg/kg over the last 5 administrations. The side effects, including mild polydipsia and polyuria, disappeared when treatment was discontinued. Depending on the stage of pregnancy, uterine contents were either resorbed or aborted, or both. Pregnancy was terminated within 2 to 16 d after the start of treatment in all treated bitches, at 2 to 5 d of treatment in 2 of 3 bitches treated at 40 to 51 d of pregnancy, and at 0 to 4 d after the end of treatment in most of the 17 bitches treated at 28 to 35 days of pregnancy. Oral administration of dexamethasone appears to be a potentially useful pharmacologic treatment for the termination of unwanted pregnancy in the bitch.

Journal Article↗
PubMed1988

Subtypes of muscarinic receptor on cholinergic nerves and atrial cells of chicken and guinea-pig hearts.

1. Electrically driven chicken and guinea-pig atria were used to investigate the negative inotropic effects of the muscarinic agonists methacholine and acetylcholine (ACh). The release of ACh from isolated hearts into the perfusate in response to (preganglionic) vagal or (pre- and postganglionic) field stimulation was bioassayed on the guinea-pig ileum or determined by labelling with [3H]-choline. 2. Concentration-response curves for the negative inotropic effect of methacholine were shifted to the right by pirenzepine in various concentrations (0.03 to 10 mumol l-1). The pA2 values were 7.76 in chicken atria and 6.53 in guinea-pig atria. Pirenzepine and atropine antagonized the negative inotropic response to 0.3 mumol l-1 ACh. The half-maximally effective concentrations (IC50) of pirenzepine (Pz) and atropine were 40 and 5.4 nmol l-1 in chicken atria and 330 and 3.5 nmol l-1, respectively, in guinea-pig atria. Thus, the respective potency ratios (IC50Pz/IC50atropine) were 7.4 and 94.3 in the two species. 3. Pirenzepine in low concentrations increased the release of unlabelled and 3H-labelled ACh from isolated hearts evoked by vagal and field stimulation only in chicken, but not in guinea-pigs. The half-maximally-effective concentration of pirenzepine was about 30 nmol l-1 in the chicken heart, whereas, in the guinea-pig heart, an increased release was observed at 300 nmol l-1. 4. (+)-Tubocurarine [(+)-Tc; 100 mumol l-1] reduced the release of ACh evoked by (preganglionic) vagal stimulation to a (+)-Tc-resistant release of about 30%. The time-course of the neuronal release of [3H]-ACh was markedly altered: the onset was delayed and the termination was extended beyond the period of stimulation (1 min or 5s) by several seconds. The (+)-Tc-resistant release was nearly abolished by 30 nmol l-1 pirenzepine. 5. In conclusion, the pre- and post-synaptic muscarinic receptors of the parasympathetic neuroeffector junction of the heart both belong to the M1-subtype in the chicken and to an M2-subtype in the guinea-pig. Block of the nicotinic ganglionic transmission in the chicken heart by (+)-Tc unmasked a muscarinic transmission, which presumably was mediated through M1-receptors stimulating a low and prolonged postganglionic release of ACh.

Acetylcholine↗
PubMed1980

Recombinant plasmids carrying promoters, genes and the origin of DNA replication of the early region of bacteriophage T7.

Two full-length contiguous HpaI fragments of the 0 to 18.2% region of T7 H DNA (HpF-H and HpG) were inserted into plasmids pHV14 or pC194 using oligo(dG . dC) connectors or synthetic HindIII adaptors. Amplification of the two early T7 fragments was achieved by transforming lysostaphin-treated S. aureus W57 with the hybrid plasmids. Experimental evidence is presented suggesting that neither of these T7 segments can be cloned in an intact form in E. coli. One of the hybrids, pHV14-HpF-H, proved to be unstable even in B. subtilis 168. The supercoiled recombinant plasmids were tested for their capacity to support RNA synthesis by purified E. coli or T7 RNA polymerases and to serve as templates in a cell-free T7 DNA replication system. The results of these in vitro studies indicate the presence of active "early" promoters in the cloned fragment HpF-H and active "late" promoters, as well as a functional origin of replication in the cloned fragment HpG.

Cloning, Molecular↗