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M Selig

Publications and source records attributed to M Selig.

17 recordsLinked to original sources
PubMed2001

Different glycolytic pathways for glucose and fructose in the halophilic archaeon Halococcus saccharolyticus.

The glucose and fructose degradation pathways were analyzed in the halophilic archaeon Halococcus saccharolyticus by 13C-NMR labeling studies in growing cultures, comparative enzyme measurements and cell suspension experiments. H. saccharolyticus grown on complex media containing glucose or fructose specifically 13C-labeled at C1 and C3, formed acetate and small amounts of lactate. The 13C-labeling patterns, analyzed by 1H- and 13C-NMR, indicated that glucose was degraded via an Entner-Doudoroff (ED) type pathway (100%), whereas fructose was degraded almost completely via an Embden-Meyerhof (EM) type pathway (96%) and only to a small extent (4%) via an ED pathway. Glucose-grown and fructose-grown cells contained all the enzyme activities of the modified versions of the ED and EM pathways recently proposed for halophilic archaea. Glucose-grown cells showed increased activities of the ED enzymes gluconate dehydratase and 2-keto-3-deoxy-gluconate kinase, whereas fructose-grown cells contained higher activities of the key enzymes of a modified EM pathway, ketohexokinase and fructose-1-phosphate kinase. During growth of H. saccharolyticus on media containing both glucose and fructose, diauxic growth kinetics were observed. After complete consumption of glucose, fructose was degraded after a lag phase, in which fructose-1-phosphate kinase activity increased. Suspensions of glucose-grown cells consumed initially only glucose rather than fructose, those of fructose-grown cells degraded fructose rather than glucose. Upon longer incubation times, glucose- and fructose-grown cells also metabolized the alternate hexoses. The data indicate that, in the archaeon H. saccharolyticus, the isomeric hexoses glucose and fructose are degraded via inducible, functionally separated glycolytic pathways: glucose via a modified ED pathway, and fructose via a modified EM pathway.

Biodegradation, Environmental↗
PubMed2000

Robotic system for biopsy and therapy of breast lesions in a high-field whole-body magnetic resonance tomography unit.

RATIONALE AND OBJECTIVES: With magnetic resonance mammography, significant progress has been achieved in the diagnosis of small breast cancers. However, biopsy and therapy of suspicious lesions must take place at a later time. Diagnosis and simultaneous biopsy and therapy in one single examination would considerably reduce costs, strain on the patient, and side effects. METHODS: ROBITOM (Robotic system for biopsy and interventional therapy of mammary lesions) is used to approach a lesion found in the breast in an image-controlled manner under a high magnetic field (eg, 1.5 T). The robotic system works in the direct vicinity of the isocenter of a magnet and consists of a trocar, coaxial sleeve, biopsy needle, laser applicator, and a control and driving unit. It contains a rack, a driving unit along the three coaxes of space, and a gripping unit for instruments or biopsy sample removal. The system has six degrees of freedom. RESULTS: In vitro experiments in pig liver including eight targets (vitamin E capsules, 4 mm in diameter) were performed. All eight capsules were hit precisely by the robotic biopsy system. The procedure was performed directly in the isocenter of a 1.5-T whole-body scanner. CONCLUSIONS: The system allows the coordinates of a lesion in the breast to be approached in a high magnetic field without shifting the patient. A combination of imaging with biopsy and subsequent therapy (eg, laser therapy or cryotherapy) seems to be feasible in the future.

Animals↗
PubMed1999

Acetyl coenzyme A synthetase (ADP forming) from the hyperthermophilic Archaeon pyrococcus furiosus: identification, cloning, separate expression of the encoding genes, acdAI and acdBI, in Escherichia coli, and in vitro reconstitution of the active heterotetrameric enzyme from its recombinant subunits.

Acetyl-coenzyme A (acetyl-CoA) synthetase (ADP forming) represents a novel enzyme in archaea of acetate formation and energy conservation (acetyl-CoA + ADP + P(i) --> acetate + ATP + CoA). Two isoforms of the enzyme have been purified from the hyperthermophile Pyrococcus furiosus. Isoform I is a heterotetramer (alpha(2)beta(2)) with an apparent molecular mass of 145 kDa, composed of two subunits, alpha and beta, with apparent molecular masses of 47 and 25 kDa, respectively. By using N-terminal amino acid sequences of both subunits, the encoding genes, designated acdAI and acdBI, were identified in the genome of P. furiosus. The genes were separately overexpressed in Escherichia coli, and the recombinant subunits were reconstituted in vitro to the active heterotetrameric enzyme. The purified recombinant enzyme showed molecular and catalytical properties very similar to those shown by acetyl-CoA synthetase (ADP forming) purified from P. furiosus.

Amino Acid Sequence↗
PubMed1998

Tumor induction of VEGF promoter activity in stromal cells.

We have established a line of transgenic mice expressing the A. victoria green fluorescent protein (GFP) under the control of the promoter for vascular endothelial growth factor (VEGF). Mice bearing the transgene show green cellular fluorescence around the healing margins and throughout the granulation tissue of superficial ulcerative wounds. Implantation of solid tumors in the transgenic mice leads to an accumulation of green fluorescence resulting from tumor induction of host VEGF promoter activity. With time, the fluorescent cells invade the tumor and can be seen throughout the tumor mass. Spontaneous mammary tumors induced by oncogene expression in the VEGF-GFP mouse show strong stromal, but not tumor, expression of GFP. In both wound and tumor models the predominant GFP-positive cells are fibroblasts. The finding that the VEGF promoter of nontransformed cells is strongly activated by the tumor microenvironment points to a need to analyze and understand stromal cell collaboration in tumor angiogenesis.

Animals↗
PubMed1998

Clioquinol-zinc chelate: a candidate causative agent of subacute myelo-optic neuropathy.

BACKGROUND: 5-chloro-7-iodo-8-hydroxyquinoline (clioquinol) was used clinically three decades ago as an oral antiparasitic agent and to increase intestinal absorption of zinc in patients with acrodermatitis enteropathica, a genetic disorder of zinc absorption. Use of clioquinol was epidemiologically linked to subacute myelo-optic neuropathy (SMON), characterized by peripheral neuropathy and blindness, which affected 10,000 patients in Japan. Discontinuation of oral clioquinol use led to elimination of SMON, however, the mechanism of how clioquinol induces neurotoxicity is unclear. MATERIALS AND METHODS: We tested the effect of clioquinol-metal chelates on neural crest-derived melanoma cells. The effect of clioquinol chelates on cells was further studied by electron microscopy and by a mitochondrial potential-sensitive fluorescent dye. RESULTS: Of the ions tested, only clioquinol-zinc chelate demonstrated cytotoxicity. The cytotoxicity of clioquinol-zinc chelate was extremely rapid, suggesting that its primary effect was on the mitochondria. Electron microscopic analysis demonstrated that clioquinol-zinc chelate caused mitochondrial damage. This finding was further confirmed by the observation that clioquinol-zinc chelate caused a decrease in mitochondrial membrane potential. CONCLUSIONS: We demonstrate that clioquinol, in the presence of zinc, is converted to a potent mitochondrial toxin. The phenomenon of clioquinol mediated toxicity appears to be specific to zinc and is not seen with other metals tested. Since clioquinol has been shown to cause increased systemic absorption of zinc in humans, it is likely that clioquinol-zinc chelate was present in appreciable levels in patients with SMON and may be the ultimate causative toxin of SMON.

Chelating Agents↗
PubMed1997

Comparative analysis of Embden-Meyerhof and Entner-Doudoroff glycolytic pathways in hyperthermophilic archaea and the bacterium Thermotoga.

The Embden-Meyerhof (EM) or Entner-Doudoroff (ED) pathways of sugar degradation were analyzed in representative species of the hyperthermophilic archaeal genera Thermococcus, Desulfurococcus, Thermoproteus, and Sulfolobus, and in the hyperthermophilic (eu)bacterial genus Thermotoga. The analyses included (1) determination of 13C-labeling patterns by 1H- and 13C-NMR spectroscopy of fermentation products derived from pyruvate after fermentation of specifically 13C-labeled glucose by cell suspensions, (2) identification of intermediates of sugar degradation after conversion of 14C-labeled glucose by cell extracts, and (3) measurements of enzyme activities in cell extracts. Thermococcus celer and Thermococcus litoralis fermented 13C-glucose to acetate and alanine via a modified EM pathway (100%). This modification involves ADP-dependent hexokinase, 6-phosphofructokinase, and glyceraldehyde-3-phosphate:ferredoxin oxidoreductase (GAP:FdOR). Desulfurococcus amylolyticus fermented 13C-glucose to acetate via a modified EM pathway in which GAP:FdOR replaces GAP-DH/phosphoglycerate kinase. Thermoproteus tenax fermented 13C-glucose to low amounts of acetate and alanine via simultaneous operation of the EM pathway (85%) and the ED pathway (15%). Aerobic Sulfolobus acidocaldarius fermented 13C-labeled glucose to low amounts of acetate and alanine exclusively via the ED pathway. The anaerobic (eu)bacterium Thermotoga maritima fermented 13C-glucose to acetate and lactate via the EM pathway (85%) and the ED pathway (15%). Cell extracts contained glucose-6-phosphate dehydrogenase and 2-keto-3-deoxy-6-phosphogluconate aldolase, key enzymes of the conventional phosphorylated ED pathway, and, as reported previously, all enzymes of the conventional EM pathway. In conclusion, glucose was degraded by hyperthermophilic archaea to pyruvate either via modified EM pathways with different types of hexose kinases and GAP-oxidizing enzymes, by the nonphosphorylated ED pathway, or by a combination of both pathways. In contrast, glucose catabolism in the hyperthermophilic (eu)bacterium Thermotoga involves the conventional forms of the EM and ED pathways. The data are in accordance with various previous reports.

Archaea↗
PubMed1995

"Streptococcus milleri" strains displaying a gliding type of motility.

Isolates belonging to the "Streptococcus milleri" species group that appear to exhibit a gliding type of motility, which is expressed as spreading growth on certain types of agar media, are described. These strains resembled a biotype of "S. milleri" that is usually isolated from genitourinary sources and is notable for its ability to ferment a wide array of carbohydrates. This biotype, which is currently included in the species Streptococcus anginosus, has been implicated in cases of neonatal infection. The "S. milleri" isolates which we studied lacked any observable organelles of motility and gave negative results when they were tested in conventional motility test medium stab cultures. Colonies growing on certain agar media, however, spread over the surfaces of plates and increased in area with increasing time of incubation. Chocolate agar supported maximum spreading, while this characteristic was barely discernible on blood agar. Electron microscopy studies revealed that there was more production of extracellular glycocalyx by motile strains than by a nonmotile isolate having a similar biotype. The results of an analysis of 16S rRNA gene sequences suggested that the motile strains are closely related to S. anginosus and represent a distinct rRNA population within the "S. milleri" species complex.

Base Sequence↗
PubMed1988

An in vitro study of the effects of androgens on the cytoskeleton of ovarian granulosa cells with special reference to actin.

Ovarian granulosa cells from small antral follicles from immature rats were cultured in a serum-free medium for 1-6 days with or without the presence of 10(-5) M dehydroepiandrosterone (DHEA) or 10(-5) M-androstenedione (delta 4-A). Control cultures reveal that the cells are flattened and contain many filamentous bundles organized as stress fibers, numerous scattered cytoplasmic actin filaments, microtubules and vimentin. Alpha actinin and myosin were shown by immunocytochemistry to have a punctate pattern along the stress fibers. For the most part, cells exposed to androgens did not flatten; however, they assumed a varied shape and contained fewer stress fibers and actin filaments. Many of these cells did not develop stress fibers and those that did develop were fewer in number and displayed--actinin and myosin in a punctate pattern. Microtubules and vimentin filaments remained unaltered when compared to controls. It is believed that the deficiency of actin filaments, coupled with certain other degenerative changes which express themselves in other cellular compartments, leads to an early atresia of the granulosa cell cultured in high concentrations of androgens.

Actinin↗
PubMed1988

A controlled trial of prehospital advanced life support in trauma.

We compared the outcome of 472 trauma patients who required ambulance attention and who received prehospital advanced life support (ALS) with another similar 589 patients who received only basic life support (BLS). Nontrapped, critically injured ALS patients were treated for an average of 13 minutes at the scene of injury, compared with 17 minutes for BLS cases (P less than .05). Seventeen of 37 ALS deaths (36%) occurred within 24 hours of injury, compared with 24 of 33 BLS fatalities (73%) (P less than .05). However, the overall case fatality rate was similar in the two groups, and regression analyses did not demonstrate an impact of ALS care on mortality. ALS resuscitation did not reduce the duration of hospital or intensive care unit stay, or the incidence of disability after head injury. However, the incidence of respiratory failure in the critically injured patients was 5% (ALS) and 19% (BLS) (P less than .025). ALS care appeared to influence patient outcome during the first 24 hours after injury, but had little impact on the later clinical course. Our sample size was too small to rule out any effect of ALS on in-hospital mortality. However, the improved 24-hour survival associated with ALS care suggests some benefit of prehospital resuscitation in major trauma.

Adult↗
PubMed1981

New South Wales intensive care ambulance system: outcome of patients with ventricular fibrillation.

Four hundred and thirty-four (2%) of the 22210 patients transported by the Intensive Care Ambulance system in Sydney, Newcastle and Wollongong during 1979, were patients with ventricular fibrillation (VF). Two hundred and eighty-two (65%) of these were pronounced dead on arrival in hospital, 152 (35%) were admitted to hospital, and 91 (21%) survivors were discharged from hospital. For 240 patients with witnessed cardiac arrest, the mean delay before the arrival of the paramedics was 15.9 +/- 3.1 SE minutes. Only one of 41 patients attended by paramedics later than 10 minutes after cardiac arrest survived to be discharged from hospital, compared with 39 of 169 patients attended by paramedics within 10 minutes of cardiac arrest. With the assistance of the Intensive Care Ambulance, 91 patients survived pre-hospital VF in New South Wales in 1979; consideration should be given to methods of minimising delays in attending these patients.

Allied Health Personnel↗
PubMed1978

Crush syndrome.

The crush syndrome has been an accompaniment of crushing injuries following disaster situations. Recognition of the sequence of events and early institution of the appropriate therapy is essential, if life is to be saved in these critically injured persons. Treatment should be begun 'on site' and arrangement then made for transport to a major medical facility as rapidly as feasible.

Acidosis↗
PubMed1977

Medical aspects of the Granville Rail Disaster.

The paper outlines the Granville Rail Disaster incident, and the Sydney Metropolitan Disaster Programme which was operational for the first time. The nature of casualties (their triage, resuscitation and evacuation) is discussed, together with a description of the medical response. Difficulties confronting rescuers are mentioned and conclusions are drawn.

Accidents↗
PubMed1977

Lignocaine kinetics in cardiac patients and aged subjects.

1 The pharmacokinetics following long term intravenous infusion of lignocaine to cardiac patients have been examined. 2 Plasma levels and half-lives of lignocaine and monoethylglycinexylidide (MEGX) showed wide inter-patient variability. 3 Toxicity reactions to therapy were associated with elevated lignocaine and/or MEGX plasma levels. 4 In a separate study the effect of age on the pharmacokinetics of lignocaine was examined using bolus doses (50 mg) of the drug to young and aged subjects. 5 Elderly subjects had significantly longer half-lives for lignocaine compared to younger individuals although no change in plasma clearance occurred. 6 The drug appeared to distribute differently in the aged as reflected by significantly increased apparent volumes of distribution. 7 The 24 h urinary recovery of the major metabolite (total 4-hydroxyxylidine) showed a significant reduction in the elderly when compared to the young. 8 The clinical significance of these studies with respect to lignocaine therapy has been discussed.

Adult↗