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Biomedical subjects

B Bachmann

Publications and source records attributed to B Bachmann.

At least 37 records · Page 2Linked to original sources
PubMed1990

[Utilization of sulfite leach by yeasts: growth parameters of producer and fusion strains].

The growth characteristics of a Candida strain (T1), a Pichia strain (T2), and of a fusion product of T2-mutants (fp-T2) have been examined in batch and continuous cultures with the single substrates xylose, acetate, glucose, mannose, and galactose or mixed substrates of them. Maximum specific growth rate (mumax), substrate saturation constant (KS), substrate inhibition (KSi), yield (Y), dilution rate (D), and the protein content of the strains have been compared. The significance of the results for the production of single cell protein is pointed out.

Candida↗
PubMed1990

Aspartokinase genes lysC alpha and lysC beta overlap and are adjacent to the aspartate beta-semialdehyde dehydrogenase gene asd in Corynebacterium glutamicum.

A 2.1 kb DNA fragment of the recombinant plasmid pCS2, isolated from an aminoethyl cysteine (AEC)-resistant and lysine-producing Corynebacterium glutamicum mutant strain, and which confers AEC resistance and lysine production on the wild-type G. glutamicum ATCC 13032 was analysed. DNA sequence analysis of this fragment revealed three large open reading frames (ORFs). The incomplete ORF1 does not contain the 5' end of the coding region. ORF2, which uses the same reading frame as ORF1, is identical to the 3' end of ORF1 and encodes a putative protein of 172 amino acids (aa) and of Mr 18,584. ORF3 encodes a putative protein of 344 aa and of Mr 36,275. The amino acid sequences deduced from ORF1 and ORF2 display strong homologies to those of the alpha- and beta-subunits of the Bacillus subtilis aspartokinase II. It is therefore proposed that the incomplete ORF1, termed lysC alpha, encodes part of the alpha-subunit of the C. glutamicum aspartokinase whereas the complete ORF2, termed lysC beta, encodes the beta-subunit of the same enzyme. ORF2 is responsible for AEC resistance and lysine production due to a feedback-resistant aspartokinase. The amino acid sequence deduced from ORF3, termed asd, is highly homologous to that of the Streptococcus mutans aspartate beta-semialdehyde dehydrogenase (ASD). Plasmids carrying the C. glutamicum asd gene complemented Escherichia coli asd mutants. Increase in ASD activity by a factor of 30-60 was measured for C. glutamicum cells harbouring high copy-number plasmids with the C. glutamicum asd gene.

Amino Acid Sequence↗
PubMed1990

Cloning of a DNA fragment from Corynebacterium glutamicum conferring aminoethyl cysteine resistance and feedback resistance to aspartokinase.

The Corynebacterium glutamicum/Escherichia coli shuttle vector plasmid pZ1 was used to clone the S-(2-aminoethyl)-D,L-cysteine (AEC)-resistance gene from a lysine-excreting, AEC-resistant strain of C. glutamicum, the aspartokinase activity of which was released from feedback inhibition by mixtures of lysine and threonine or AEC and threonine respectively. A recombinant plasmid designated pCS2 carrying a 9.9-kb chromosomal insert that conferred AEC resistance and the ability to excrete lysine to its host was isolated. The aspartokinase activity of the pCS2-carrying strain was resistant towards inhibition by mixtures of lysine and threonine or AEC and threonine respectively. By deletion analysis the DNA region conferring AEC resistance to the host and feedback resistance to its aspartokinase activity could be confined to a 1.2-kb DNA fragment.

Aspartate Kinase↗
PubMed1990

A novel proviral clone of HIV-2: biological and phylogenetic relationship to other primate immunodeficiency viruses.

Infectious molecular clones of the human immunodeficiency virus type 2 (HIV-2) will be valuable tools for the study of regulatory gene functions and the development of an animal model for the human acquired immunodeficiency syndrome (AIDS). To this end, we have cloned and sequenced a novel HIV-2 isolate, HIV-2BEN. One clone, designated MK6, is infectious for various human T-cell lines and for human and macaque peripheral blood lymphocytes (PBL), allowing molecular studies of HIV-2 infection and replication. Since MK6 is highly cytopathic in MT-2 and Molt-4 clone 8 cells, antiviral agents and neutralizing sera may be tested. Cluster analysis of HIV-1, HIV-2, and simian immunodeficiency virus (SIV) env and gag genes revealed that HIV-2BEN yielded the earliest node of phylogenetic divergence for all reported HIV-2 sequences. Noise analysis showed that, with the current data, no specification of any branching order can be made among the four groups of primate lentiviruses, HIV-1, HIV-2/SIVSMM/MAC, SIVAGM, and SIVMND.

Animals↗
PubMed1990

Protein binding of prilocaine in human plasma: influence of concentration, pH and temperature.

Protein binding of prilocaine was investigated in vitro under various conditions of changing pH, temperature and total plasma concentration by means of HPLC with UV-detection and ultrafiltration. Whereas changes in temperature (25 degrees C-40 degrees C) and pH (pH 5-pH 10) influenced protein binding markedly, rising plasma concentrations up to 16 micrograms/ml did not affect plasma protein binding significantly. This may be a possible explanation for clinical evidence of low toxicity associated with the use of prilocaine. Discussions concerning protein binding of local anaesthetics should always be based on defined ambient conditions (pH, temperature, concentration).

Aged↗
PubMed1990

[The uterine motility of cattle during late pregnancy, labor and puerperium. I. Spontaneous motility].

In the present study spontaneous uterine motility was recorded in 4 cows during late pregnancy, parturition and the puerperium using pressure microsensors and electrodes which were surgically implanted into the myometrium of the pregnant horn 3 to 4 weeks before parturition. Hysterograms were evaluated by means of pressure amplitude, frequency, duration, interval of uterine contractions and also by electromyography. During the last 2-3 weeks of pregnancy only single weak uterine contractions of different intensity were seen. About 18-20 hours a.p. frequency and amplitude of mainly tubocervical directed waves continuously increased. When the fetus entered the birth canal and especially during expulsion of the calf extremely strong irregular contractions occurred, which became very regular during the first hours p. p. After the placenta has been released 3-8 hours p. p., spontaneous uterine motility drastically decreased until the second postpartal week, when it started to increase again.

Animals↗
PubMed1989

Cloning and nucleotide sequence of the phosphoenolpyruvate carboxylase-coding gene of Corynebacterium glutamicum ATCC13032.

As a first step in determining the importance of the anaplerotic function of phosphoenolpyruvate carboxylase (PEPC) in amino acid biosynthesis, the ppc gene coding for PEPC of Corynebacterium glutamicum ATCC13032 has been cloned by complementation of an Escherichia coli ppc mutant strain. PEPC activity encoded by the cloned gene is not affected by acetyl-CoA under conditions where the E. coli enzyme is strongly activated, whereas acetyl-CoA is able to relieve inhibition by L-aspartate used singly or in combination with alpha-ketoglutarate. Amplification of the ppc gene in a C. glutamicum lysine-excreting strain resulted in increased PEPC-specific activity and lysine productivity. The nucleotide sequence of a DNA fragment of 4885 bp encompassing the ppc gene has been determined. At the amino acid level, PEPC from C. glutamicum presents overall a high degree of similarity with corresponding enzymes from three different organisms. The location of some strictly conserved regions may have important implications for PEPC activity and allostery.

Amino Acid Sequence↗
PubMed1989

[Maternal and neonatal bupivacaine plasma levels in peridural anesthesia for relief of labor pain].

Peripheral venous blood samples were drawn for bupivacaine analyses (gas chromatography) from 24 patients under epidural anaesthesia, used to reduce pain caused by contractions. The specimens were taken 10, 20, 30 and up to 45 minutes following a first injection of 11 to 13 ml bupivacaine 0.25%, before, 15 as well as 30 minutes after each repetitive dose and at childbirth. Immediately after cord clamping, blood sampling in the neonate was performed to evaluate bupivacaine concentrations in the umbilical artery and vein. Additionally, apgar scores and blood gas parameters were checked and compared with those of neonates, born without analgesic treatment of their mothers. Using bupivacaine 0.25% (average 12 ml) for epidural anaesthesia, the peak plasma levels (mean = 0.2 micrograms/ml) were found 10 minutes after application of the analgesic dose. In one patient a maximum bupivacaine plasma concentration (0.47 micrograms/ml) was determined 15 minutes after the second repetitive dose of 5 ml bupivacaine 0.25%. Apgar scores and results of blood gas analyses demonstrated no significant difference between neonates born spontaneously under regional anaesthesia or without any analgesic treatment of their mothers, respectively. Using bupivacaine 0.25% in epidural anaesthesia for pain relief in labour, we found maternal and neonatal plasma concentrations of the local anaesthetic drug far below the accepted threshold level which might produce systemic toxic reactions.

Adolescent↗
PubMed1989

[Serum immunoglobulin concentrations in patients following bone marrow transplantation and preventive administration of high-dose nonspecific or normal-dose CMV-specific immunoglobulin].

Ten consecutive bone marrow transplant recipients were assigned alternatively to receive either a high dose polyspecific intravenous immunglobulin (HDIVIG) 0.5 g/kg weekly X 14, or a conventional dose of a CMV specific intravenous immunglobulin (CMVIG) 0.1 g/kg every three weeks. Before and after each application we determined the levels of total IgG, IgG subclasses, IgG 1, IgG 2, IgG 3, IgG 4, total IgA and IgM and of specific IgG and IgM antibody concentrations against endotoxin, lipid A, streptococcus A, hemophilus, EBV and CMV. In the HDIVIG, total IgG rose from 11 (median, range 2-11) g/l to 25 (22-32) g/l by day 89, in the CMVIG group, IgG dropped from 11 (10-15) g/l to 9 (6-12) g/l. In the same period the mean levels of IgG subclasses expressed as % of normal plasma pool increased in the HDIVIG group in all subclasses, not in the CMVIG group. The differences were significant, however, only for IgG 1 and IgG 2. IgG-antibodies against CMV, EBV, endotoxin, streptococcus and hemophilus did increase significantly in the HDIVIG group, but not in the CMVIG group. No increase was seen in both groups in lipid A antibodies and in specific IgM antibodies. Each application of CMVIG induced a transient increase of anti-CMV antibodies. We conclude that HDIVIG induces reproducibly an increase of specific and non-specific IgG antibodies. No attempt was made to assess clinical outcome. However, these results provide a rational basis for further therapeutic studies.

Adult↗
PubMed1988

[Sedative-analgesic medication in intensive care patients needing ventilator treatment].

UNLABELLED: It was the aim of this study to compare two regimens for sedation and analgesia during ventilator treatment in intensive care patients. Special regard was given to endocrine stress response, neuro-monitoring, hemodynamic parameters and clinical practicability. METHODS: A total number of 16 patients of an operative ICU were randomly allocated to the following groups: (1) Fentanyl-group, approximately 0.2 mg/h fentanyl, 2.5 mg/h midazolam and 2 mg/h pancuronium in intermittent doses, (2) ketamine-group, about 50 mg/h ketamine and 2.5 mg/h midazolam by syringe pump, in addition 2 mg/h pancuronium. During a period of 2 days and in intervalls of 6 h, plasma levels of epinephrine and norepinephrine (by HPLC/ECD), ADH, ACTH and cortisol (by RIA), ketamine (by GC) and stress-metabolites (glucose, lactate, free glycerol) were determined. Hemodynamic parameters were investigated in intervalls of 12 h, EEG (Compressed Spectral Array, CSA) in intervalls of 24 h. In addition, routine laboratory data, vigilance and adaptation to the respirator were observed. RESULTS: Plasma levels of adrenaline, noradrenaline, dopamine, ADH, ACTH, cortisol and stress-metabolites were comparable in both groups. Levels of ADH, ACTH, cortisol and free glycerol did not leave the normal range. In three patients, in which epinephrine- or norepinephrine-infusions were necessary to improve cardiocirculatory stability, this treatment could be finished after beginning of the ketamine application. In both groups, CSA showed a dominant delta- und theta-activity according to the clinical aspects of sufficient sedation and analgesia. Hemodynamic parameters were comparable in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

[Experiences with parenteral administration of diltiazem in coronary surgery patients].

Diltiazem is a calcium channel blocker whose effects lie between those of the two other important calcium antagonists nifedipine and verapamil. In addition to vasodilation, it has a negative dromotropic effect with prolongation of the A-V interval. In animal experiments and human investigations, diltiazem improves the function of ischemic myocardium due to a direct dilating effect on coronary vessels. The purpose of the present study was to investigate the hemodynamic effects of diltiazem in patients before and during coronary revascularization. METHODS. The study included 60 consenting male patients with coronary heart disease. Twenty premedicated patients randomly received 0.3 mg/kg diltiazem or placebo within 3 min before induction of anesthesia. Hemodynamic measurements (arterial pressure, heart rate, mean pulmonary arterial pressure, pulmonary capillary pressure, right atrial pressure and cardiac output) were taken during the following 21 min. Before cannulation of the great vessels for institution of extracorporeal circulation (ECC), 20 other patients received 0.014 mg diltiazem or placebo/kg per min over 20 min. In addition to the above mentioned hemodynamic measurements, left ventricular parameters (LVP, LVEDP, dp/dt) were directly registered, and 5 min after the end of ECC the measurements were repeated with the same preload as before the ECC. Twenty additional patients received 0.014 mg diltiazem or placebo/kg per min within 21 min during ECC observing arterial perfusion pressure and oxygenator volume. RESULTS. Pre- and intraoperatively diltiazem caused a decrease in mean arterial pressure; cardiac index increased only during the preoperative investigation period (Tables 1, 2), whereas stroke volume index increased pre- and intraoperatively; heart rate decreased in all patients as well as dp/dt (Fig. 1).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, General↗
PubMed1988

[Plasma concentrations of lidocaine and prilocaine following infiltration anesthesia in otorhinolaryngologic surgery].

UNLABELLED: Infiltration anaesthesia is still relevant for the surgical treatment of patients in otorhinolaryngology. The injection of local anaesthetics in well vascularised areas constantly causes the danger of high plasma concentrations of local anaesthetics combined with undesirable side effects. In our study we tried to determine the development of plasma concentrations of local anaesthetics in patients scheduled for routine tonsillectomies and tympanoplasty. MATERIALS AND METHODS: In 45 patients the development of plasma concentrations was measured immediately after the injection at short intervals; the samples were obtained between 1 minute and 60 minutes after the first injection. Group 1: Lidocaine 0.5% with epinephrine (1:200,000) 15-20 ml for tonsillectomy (n = 18). Group 2: Lidocaine 0.5% with epinephrine (1:200,000) 8-15 ml for tympanoplasty (n = 15). Group 3: Prilocaine 1% with epinephrine (1:200,000) 8-15 ml for tympanoplasty (n = 15). For tactical reasons infiltration anaesthesia for the patients of group 2 was - in addition to general anaesthesia - applied by the otorhinolaryngologist, whereas the patients of groups 1 and 3 were operated exclusively under local anaesthesia. RESULTS: Within the first minute after the initial injection plasma concentrations of the local anesthetic increased close to toxic threshold levels that are associated with undesirable systemic side effects. In the patients of group 1, who underwent tonsillectomy, plasma concentrations of 4-7 micrograms/ml were found during the first minute. The highest average values always appeared within the first five minutes: group 1 2.07 micrograms/ml, group 2: 0.45 micrograms/ml, and group 3: 1.15 micrograms/ml. DISCUSSION: With infiltration anaesthesia in well vascularised areas it may happen that there are--mainly in the early stage--high plasma concentrations of the applied substances, although the total dose was below the known maximum. Despite careful technique (repeated aspiration test in two levels) at least partial intravascular injections are apparently not always avoidable according to the pharmacokinetic data. Our results demonstrate that in addition to a safe peripheral venous line and prophylactic oxygen therapy, intraoperative monitoring of blood pressure, heart rate, electrocardiogram and verbal patient monitoring is of advantage in this group of patients. In our opinion the "standby function" of an anaesthesiologist can avoid severe complications.

Adolescent↗
PubMed1987

Deoxyribonucleotide biosynthesis in green algae: characterization of thymidylate synthase-dihydrofolate reductase in Scenedesmus obliquus.

Thymidylate synthase and dihydrofolate reductase are peak enzymes that accompany the S phase of the unicellular green algae, Scenedesmus obliquus, and are both overproduced in the presence of 5-fluorodeoxyuridine. Such overproducing cultures have served for enzyme isolation and characterization. It has not been possible to separate the two enzyme activities by several methods of protein fractionation, including affinity chromatography on specific immobilized ligands (fluorodeoxyuridylate or N10-formylfolate); both were enriched in parallel approximately 400-fold from algal extracts. The most highly purified samples are of low stability in solution. Enzyme activities are inhibited by methotrexate, 5-fluorodeoxyuridylate, and arabinouridylate but not by hydroxyurea; FdUMP inhibition is fully reversed after removal of the nucleotide. Sedimentation in sucrose gradients (Mr 100,000) and electrophoresis in denaturing polyacrylamide gels (Mr 50,000) suggest that the protein structure resembles more the dimeric, bifunctional thymidylate synthase-dihydrofolate reductase of protozoan species than the separate enzymes found in bacteria and animal cells.

Chlorophyta↗
PubMed1987

[Hemodynamic action profile of propofol in comparison with midazolam. A study in coronary surgical patients].

Propofol, a rapid and short-acting i.v. anesthetic, was associated with the risk of anaphylactic reactions in its original cremophor-EL formulation. It has been reformulated in a soybean emulsion with satisfactory anesthetic properties. A former study of hemodynamic changes after i.v. induction with propofol, thiopental, methohexital, etomidate, and midazolam in patients with coronary artery disease demonstrated that in comparison to other induction agents propofol depressed systolic and diastolic arterial pressures more severely, compromising coronary perfusion. In the present investigation left ventricular parameters as well as hemodynamic effects during extracorporeal circulation (ECC) were studied in comparison to midazolam during opiate analgesia. Methods. Hemodynamic effects of 2 mg/kg body weight propofol as compared to 0.15 mg/kg midazolam were studied in 34 patients during coronary artery surgery before cannulation of the large vessels (measurement of left ventricular parameters) or during ECC (measurement of arterial perfusion pressure and oxygenator volume). Results (see Table 1, Figs. 1 and 2). Propofol decreased systolic and diastolic pressures (-27%, -22%) more than midazolam (-10%, -9%). Cardiac index and stroke volume index were diminished following both drugs (propofol: -14%, -9%; midazolam: -15%, -11%); total systemic resistance was reduced significantly by propofol (-22%). Dp/dtmax was compromised more markedly by propofol (-24%) than by midazolam (-18%), but there was no significant difference.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1987

[The endocrine stress-reaction to orotracheal intubation and topical anesthesia with lidocaine].

The influence of laryngoscopy and intubation with or without topical lidocaine anesthesia on the endocrine stress response was investigated in six groups of 40 orthopedic surgery patients differing in premedication and technique of lidocaine application (one- or two-step method). Controls were included without lidocaine application. Plasma levels of catecholamines (by HPLC) were measured before induction and 1, 5, and 10 min after intubation, ADH-levels (by RIA) before induction and 5 and 10 min after intubation. In addition, mean arterial pressure (MAP, MAP), HR, and the incidence of coughing and cardiac arrhythmias were observed. The statistical evaluation (analysis of variance with repeated measures on one factor) considered P values of less than 0.05 significant. There was no influence of laryngoscopy and intubation on plasma catecholamine levels during the observation period. A continuous decrease in both levels of epinephrine and norepinephrine was significant. ADH levels showed no significant changes. Lidocaine had no influence on these endocrine parameters. MAP and HR increased after intubation in all groups studied. The increase in HR was less pronounced after lidocaine treatment. Coughing (4 patients) and ventricular dysrhythmia (2 patients) were observed only in patients without lidocaine treatment. In conclusion, no influence of different modes of treatment on the endocrine stress response during intubation became obvious. There was no indication that the cardiovascular symptoms during laryngoscopy and intubation are caused by systemic stress. An explanation may be a direct neural impulse via sympathetic efferents to the heart. On the other hand, topical application of lidocaine did prevent coughing and cardiac irritation, and the increase in HR was attenuated.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMed1986

[Fibrinolytic therapy of massive pulmonary embolism on the 1st postoperative day following cholecystectomy].

Two patients, aged 64 and 47 years, had a massive pulmonary embolism one day after cholecystectomy. Ultra-short fibrinolysis was undertaken with 1.5 million units of streptokinase. Both patients rapidly improved, with a fall in heart rate, pulmonary artery or central-venous pressure, and a rise in arterial pO2. There were no significant bleedings. Ultra-short fibrinolysis (maximally over one hour) can thus successfully lyse emboli--consisting of fresh plasminogen-rich coagulation thrombi in the early postoperative period--without re-opening wound- and capillary beds during this short period.

Cholecystectomy↗
PubMed1986

[Anesthesia procedures and perioperative patient monitoring in chemonucleolysis].

Premedication with H1 and H2 blockers as well as cortisone to reduce or prevent allergic reactions should be an integral part of the overall treatment. The facilities for immediate treatment of anaphylactic reactions including cardiopulmonary resuscitation must be readily available. Our haemodynamic measurements allow us to give a negative answer to the question--so far not investigated in man--whether the use of chymopapain or of its fragments leads to constant cardiocirculatory effective reactions in the early phase. Our experiences collected so far favour catheter peridural anaesthesia as the method of choice in chemonucleolyses.

Anesthesia↗