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H Baur

Publications and source records attributed to H Baur.

35 records · Page 2Linked to original sources
PubMed1986

Expression of biosynthetic genes from Pseudomonas aeruginosa and Escherichia coli in the heterologous host.

We examine the expression of constitutive or repressible, monocistronic genes from Pseudomonas aeruginosa and Escherichia coli after their transfer to the heterologous host. To this end, chromosomal DNA from P. aeruginosa was cloned into the mobilizable broad-host-range vector pKT240; recombinant plasmids carrying the argA, argF, or proC genes were identified by complementation of the corresponding auxotrophic mutations. The isofunctional E. coli genes and the E. coli proB gene were subcloned into pKT240 from existing recombinant plasmids. The enzyme expression specified by the Pseudomonas genes in E. coli, calculated per gene copy, ranged from 0.3%-5% of the levels observed in Pseudomonas. Fusion of the P. aeruginosa proC gene to the E. coli consensus tac promoter resulted in very high proC enzyme production in E. coli, indicating that, at least in this case, the expression barrier is essentially at the level of transcriptional initiation. The E. coli argA and argF enzymes, which are controlled by repression in their native host, were synthesized constitutively in P. aeruginosa at 5% of the levels measured in E. coli under derepressed conditions. The constitutive E. coli proB and proC genes were expressed at high levels (ca. 50%) in the heterologous host. These results support the idea that P. aeruginosa may be a more permissive host than E. coli for the heterologous expression of genes from gram-negative bacteria.

Chromosomes, Bacterial↗
PubMed1985

[Anesthesia-related maternal mortality during labor. Results of a survey in the Federal Republic of Germany 1971-1980].

In order to obtain figures on the anaesthesia related maternal mortality in the Federal Republic of Germany, 707 hospitals have been addressed via questionnaire. Hospitals where obstetric departments and anaesthetic departments as well were available, were investigated for maternal mortality, anaesthetic requirements, and the complications which led to the maternal deaths during the period of 1971-1980. 38% (259 general hospitals and 10 university hospitals) responded; the geographical distribution seemed to be representative. The average maternal mortality rate was at 0.21%, which ranged from 0.21% for general hospitals to 0.16% for university hospitals. The overall anaesthesia related maternal mortality was around 6.4%. 20 of the reported 21 maternal deaths occurred under general anaesthesia and 1 under local anaesthesia; 17 patients died during caesarean section and 4 during vaginal delivery. The main complications which led to the maternal deaths were cardiac arrest and aspiration of gastric content with 38,1% each and convulsions with 4.8%. In 19% of the total maternal deaths the causes could not be determined. The importance of obstetric centres and of controlled anaesthetic methods delivery will be discussed on the basis of these and other figures which have been reported in the literature.

Anesthesia, Conduction↗
PubMed1980

An outpatient approach to female sterilization with methylcyanoacrylate.

MCA is a tissue adhesive which can be delivered transcervically to the Fallopian tubes by means of the FEMCEPT device. In the patients treated with this system, both prior to hysterectomy and on an ambulatory basis, there have been no significant complications or side effects. In the most recent series of ambulatory patients treated with the REMCEPT-MCA system, the bilateral tubal closure rate was 78%.

Ambulatory Care↗
PubMed1980

Correlation of nucleic acid binding by metabolites of trans-4-aminostilbene derivatives with tissue specific acute toxicity and carcinogenicity in rats.

The reaction with macromolecules was determined in various tissues of female Wistar rats 24 h following a single oral administration of [3H]-trans-4-dimethylamino- and [3H]-trans-4-acetylaminostilbene. Total binding to proteins was 4-9 times greater than to nucleic acids in most tissues. Binding to RNA and DNA was very similar and greatest in liver, about 1/4 in kidney and 1/8 - 1/10 in lung, glandular stomach (target tissue for acute toxicity), bladder, mammary glands and Zymbal glands (target tissue for carcinogenicity). The target tissues, therefore, appear not to be notably exposed to reactive metabolites. The pattern of adducts was analyzed by Sephadex LH20 chromatography of RNA and DNA hydrolysates from liver, glandular stomach, lung and kidney. It was found to be very similar qualitatively. DNA-bound metabolites were very persistent in the non-target tissues liver and kidney, t 1/2 being 34 and 60 days, respectively. Some of the major adducts in liver were not eliminated at all within 4 weeks. It thus appears that aminostilbene derivatives represent examples of strong and genotoxic carcinogens for which the extent and persistence of primary DNA lesions are not correlated with the biological effect.

Animals↗
PubMed1979

Transient 45Ca uptake and release in isolated rat-liver cells during recovery from deenergized states.

1. Aerobic incubation of isolated rat liver cells--after dilution from the anaerobic stock suspension--transiently brings about a state, during which a reversible calcium uptake can be observed on addition of a respiratory substrate. Uptake varies greatly and can reach more than 50 nmol/mg protein, but declines to zero on prolonged preincubation, especially at higher temperature. Repeated additions of succinate or 3-hydroxybutyrate evoke new calcium transients. If ATP is simultaneously added, if greatly potentiates succinate-initiated reversible uptake. 2. If rotenone is present during the preincubation phase, calcium transients are strongly enhanced. Uptake is blocked by uncouplers and respiratory inhibitors, indicating the involvement of mitochondria. 3. Calcium uptake is not accompanied by increased oxygen consumption. The actual respiration cannot account sufficiently for the energy need of calcium uptake. Participation of cytoplasmic ATP is likely, as inhibitors of adenine nucleotide translocase affect uptake. 4. Lanthanum enhances calcium uptake in contrast to its action on mitochondria. 5. Pulse-labeling experiments indicate that the calcium taken up is removed from a rapidly exchangeable calcium pool by withdrawal into the mitochondria as a deep compartment. 6. Calcium uptake is accelerated either by increasing the phosphate level or by high temperature. It is prolonged by low temperature, high pH or high ATP concentration. Calcium release accelerates with increasing temperature, decreasing pH and a further rise in phosphate concentration. 7. The dependency on phosphate and temperature reveals a delicately poised equilibrium of uptake and release. At ambient temperature, phosphate increases uptake up to a concentration of 0.5 mM. Higher concentrations accelerate both uptake and release. At lower temperature, the accelerating effect on uptake predominates. A temperature shift during incubation results in adaptation of the calcium equilibrium to the new temperature, i.e. release of calcium at high temperature, uptake at low temperature. 8. Oxidizing metabolites inhibit succinate-stimulated calcium uptake and promote release of previously accumulated calcium. An increased sensitivity to phosphate is established. 9. With respect to isolated mitochondria, isolated liver cells appear to be a more realistic model for studying the physiological mechanism of mitochondrial calcium release, since compartmental constraints and regulations are maintained.

Aerobiosis↗
PubMed1977

Transport of hexoses across the liver-cell membrane.

The uptake of radioactively labelled hexoses into the cellular space of isolated liver cells has been studied using silicone layer filtering centrifugation. From the hexoses tested, D-glucose is transported most rapidly followed by D-galactose and D-fructose. The rate of L-glucose transport is only 5% of that of D-glucose. This transport enables the concentration of free aldohexoses in the cellular space to reach the external concentration. For D-glucose the rate of transport into the cell largely exceeds the rate of metabolic conversion. This is different with D-fructose where the rate of transport is considerably lower but the rate of metabolism higher. Here the transport may even be a limiting step. The transport of D-glucose and D-galactose shows a saturation characteristic, whereas D-fructose appears not to be saturatable. The Km for D-glucose is found to be 30 mM. All these hexoses compete with each other for transportation. The temperature dependency of D-glucose reveals an activation energy of 22 kcal (92 kJ)/mol (4-18 degrees C) and 7 kcal (29 kJ)/mol (18-37 degrees C). The transport of D-glucose, D-galactose and D-fructose in inhibited by cytochalasin B, phloretin and phlorizin. It is not dependent on Na+ ions. Preliminary results showed no stimulation of the transport by insulin. It is concluded that D-glucose and other hexoses are transported by carrier-mediated diffusion across the plasma membrane of liver cells. This transport shows a large resemblance to the transport of D-glucose into human erythrocytes.

Animals↗
PubMed1977

Consequences of myocardial reperfusion following temporary coronary occlusion in pigs; effects on morphologic, biochemical and haemodynamic findings.

The effects of myocardial reperfusion have been examined following a 1 h coronary occlusion and compared to a permanent coronary ligation in pigs. Haemodynamic investigations were carried out throughout the surgical intervention and repeated after 7 days. Cellular injury was estimated by serial serum enzyme determinations (creatin phosphokinase, alpha-hydroxybutyric dehydrogenase, aspartate aminotransferase, lactic dehydrogenase) during the first 5 postoperative days; infarct size was assessed morphometrically by a histochemical staining procedure 1 week after the temporary or permanent coronary occlusion. A linear correlation was found between the logarithmically plotted peak serum activity of AST, HBDH, CPK and the morphometrically determined infarct size. Based upon enzyme and morphometrical studies no significant difference could be detected between the two experimental groups. In the animals subjected to transient coronary occlusion, however, the development of a ventricular aneurysm had been prevented to early and sustained reperfusion. Early re-establishment of coronary circulation appears to accelerate the proliferation of a more resistant granulation tissue into the infarcted area. Cardiac performance was not improved by myocardial reperfusion.

Animals↗
PubMed1976

Suxamethonium-induced hyperkalaemia in patients with severe intra-abdominal infections.

In nine patients, undergoing repeat operations because of severe intra-abdominal infection developing after major abdominal surgery, serum potassium concentrations were monitored during induction of anaesthesia. Four patients showed an increase of serum potassium ranging from 2.5 to 3.1 mmol/litre above baseline values within 3-6 min after suxamethonium 100 mg i.v. In five patients there was no change. The four patients demonstrating an increase had suffered from pyrexia and leucocytosis for at least 2 weeks. The other five had signs of infection for no more than 9 days. It is concluded that patients with signs of severe intra-abdominal infection lasting longer than 1 week represent an additional category susceptible to suxamethonium-induced hyperkalaemia. They should receive only non-depolarizing muscle relaxants. When the use of suxamethonium is unavoidable, the injection of a non-depolarizing muscle relaxant before the administration of suxamethonium is recommended.

Abdomen, Acute↗
PubMed1976

[Suxamethonium-induced hyperkalaemia in patients with severe intraabdominal infections (author's transl)].

A serious danger to the circulation following the administration of suxamethonium is known to occur in patients reacting with an abnormal release of potassium. So far the following groups of patients have been found to be at an increased risk: burns, multiple trauma, tetanus, neurological disorders, uraemia. As a result of our investigations patients with severe intraabdominal infections are also to be regarded as at risk. Four of ten patients with this diagnosis have shown an increase of serum-potassium of more than 2.5 mequiv/l following suxamethonium injection in spite of a prophylactic small dose of nondepolarizing relaxant. The predisposing factors are high fever of over a week's duration and a leucocytosis of more than 10,000/cu. mm. A possible hypothesis and pathogenesis of the abnormal efflux of potassium is discussed. Prophylaxis consists of using only nondepolarizing relaxants in these cases. When there is a special indication for suxamethonium the potassium increase can be lessened if the patient is given a small dose of nondepolarizing relaxant prior to the administration of suxamethonium.

Abscess↗
PubMed1975

Criteria of viability of isolated liver cells.

36.4 +/Various cellular parameters were measured with regard to their usefulness as criteria of viability of isolated cells. Stainability by trypan blue and release of lactate dehydrogenase indicate only severe irreversible damage of cells. Neither endogenous respiration nor even the ATP/ADP ratio is a sensitive criterion of viability. On aging of cells, the ATP/ADP ratio remains high, even though the membrane potential, the intracellular K concentration and the content of adenine nucleotides decrease considerably. A sensitive, easily performed test is the stimulation of cellular respiration by 1mM succinate. Only a damaged plasma membrane allows succinate permeation of a rate sufficient to stimulate respiration. The membrane potential and the intracellular Na and K concentrations are the most sensitive criteria of viability, since they indicate the earliest changes on aging. (For freshly isolated cells, we found a membrane potential of 36.4 "/- 3.4 mv [n = 5], an intracellular K concentration of 109.0 +/- 9.1 mM, and an intracellular Na concentration of 47.0 +/- 13.4mM.) The incorporation of [14C]uridine also sensitively reflects cellular damage.

Adenosine Diphosphate↗