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Biomedical subjects

U Klein

Publications and source records attributed to U Klein.

At least 127 records · Page 7Linked to original sources
PubMed1989

Preoperative prism adaptation test in normosensoric strabismus.

In 19 patients with normosensoric esotropia, the squint angles measured with the alternate cover test were compared with those after prolonged prismatic correction of the squint angle and with those after prolonged occlusion of one eye. All patients showed an increase of the squint angle after prism adaptation. The angle was generally smaller after diagnostic occlusion of one eye than after prism adaptation. We assume that the increase in the squint angle after prism adaptation is caused by an anomalous sensorial relationship between the two eyes that was not detected with the usual psychophysical tests. Surgery tailored to the squint angle after prism adaptation seems advisable in patients with normosensoric esotropia.

Adaptation, Ocular↗
PubMed1989

[A comparison between high-frequency jet ventilation (HFJV) and conventional positive end-expiratory pressure ventilation (CPPV)--an experimental study on dogs with acute lung damage].

In a controlled study on 24 dogs with severe damage to the lungs HFJV was compared to CPPV on the basis of selected cardiorespiratory parameters. The pulmonary damage was produced by injection of oleic acid (OA) into the right atrium under conventional mechanical ventilation (IPPV). After the damage, the dogs were randomly allotted into one of two groups. Twelve dogs (group I) were ventilated for 5 hours with a PEEP of 10 cm H2O (1 kPA), 12 animals (group II) for 5 hours with HFJV. The oleic-acid-induced damage results in the known hypoxaemia with an increase in the intrapulmonary shunt. After changing to CPPV, the PaO2, which fell from 27.2 +/- 3 kPa to 10.8 +/- 2.9 kPa, rises to 20.3 +/- 7.7 kPa, but shows no further significant alteration until the end of the experiment. In contrast to the clearly improved oxygenation, essential cardiocirculatory parameters (CI, SVI, RVSWI, LVSWI, TCO2) are partially reduced by more than 50% of the initial values. PAP, PCWP, HR, TPR and PVR increase significantly, MAP remaining nearly unchanged. After changeover to HFJV, there is first a further fall of PaO2 from 11.1. +/- 3.0 kPa to 9.1 +/- 1.4 kPa following OA, then, however, until the end of the experiment, a continuous elevation to 15.6 +/- 2.4 kPa with a mean airway pressure that is by 75% lower. The haemodynamic parameters show no significant changes as compared to the initial values, overall, however, they lie significantly below or above those of group I. The results from our investigations allow to draw the conclusion that, despite haemodynamic advantages, HFJV in consequence of deterioration of the arterial oxygenation currently is no alternative superior to CPPV in ventilating the severely damaged lung.

Animals↗
PubMed1989

[Building and performance of the Jena system for normal frequency injector (jet) ventilation in endoscopic treatments].

Experiences with three variants of use of normofrequency injector (jet)-ventilation during endoscopic procedures in laryngo-tracheobronchial area are reported. The used simple instruments and the efficiency of the method with regard to the gas exchange of the patients are described. Moreover, experimental investigations of the Kleinsasser laryngoscopic equipment at the lung model were performed. Problems of the supervision and non-endoscopic applications of the method are mentioned.

Anesthesia↗
PubMed1989

[The use of the jet ventilation technic in surgical interventions on the trachea].

Based on our own experiences and on comparisons with the literature, we demonstrated the possibilities and problems of jet ventilation technique during surgical interventions at the trachea. This method has been applied 28 times and in two cases surgical manipulations caused complications in the form of bronchial bleedings, with the occurrence of hypoventilation in one case. Due to the essentially improved prerequisites for the surgeon and optimal ventilation, the procedure of jet ventilation presents a true enrichment of the anaesthesiological repertoire, provided the indications are well established and the cooperation between surgeon and anaesthetist is good. On the other hand, however, owing to insufficiencies in the adequate monitoring if this form of ventilation, a comparably higher risk for the patient has to be taken into account.

Adult↗
PubMed1988

Localization of Nitrogen-Assimilating Enzymes in the Chloroplast of Chlamydomonas reinhardtii.

The specific activities of nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthase, and glutamate dehydrogenase were determined in intact protoplasts and intact chloroplasts from Chlamydomonas reinhardtii. After correction for contamination, the data were used to calculate the portion of each enzyme in the algal chloroplast. The chloroplast of C. reinhardtii contained all enzyme activities for nitrogen assimilation, except nitrate reductase, which could not be detected in this organelle. Glutamate synthase (NADH- and ferredoxin-dependent) and glutamate dehydrogenase were located exclusively in the chloroplast, while for nitrite reductase and glutamine synthetase an extraplastidic activity of about 20 and 60%, respectively, was measured. Cells grown on ammonium, instead of nitrate as nitrogen source, had a higher total cellular activity of the NADH-dependent glutamate synthase (+95%) and glutamate dehydrogenase (+33%) but less activity of glutamine synthetase (-10%). No activity of nitrate reductase could be detected in ammonium-grown cells. The distribution of nitrogen-assimilating enzymes among the chloroplast and the rest of the cell did not differ significantly between nitrate-grown and ammonium-grown cells. Only the plastidic portion of the glutamine synthetase increased to about 80% in cells grown on ammonium (compared to about 40% in cells grown on nitrate).

Journal Article↗
PubMed1988

[Behavior of respiratory tract, esophagus and pulmonary artery pressure in bronchoscopies in normofrequent jet ventilation in comparison with Friedel's ventilation technics].

The dynamics of selected physiological respiratory parameters were studied in a total of 29 patients. During slight hyperventilation and good oxygenation by both Friedel's and jet ventilation (driving pressure 0.3 and 0.4 MPa, respectively), comparably low respiratory tract pressures were observed. Transmission to intrathoracic (44-46%) and mean pulmonary artery pressure (11-13%) indicates only a low-grade ventilation-induced hemodynamic influence. By contrast, clear increases in pulmonary artery pressure due to intubation were recorded. Thus, the employed normofrequent jet ventilation with its continuous open-tube ventilation which is independent of the undisturbed bronchological examination possesses beneficial properties from a cardiorespiratory view.

Adult↗
PubMed1987

Intracellular Carbon Partitioning in Chlamydomonas reinhardtii.

Using enzymic and isotope techniques the intracellular partitioning of newly fixed carbon was studied in synchronized cells of Chlamydomonas reinhardtii. Starch and growth metabolism, i.e. the use of carbon in biosynthesis, were found to be the major sinks for photosynthetically fixed carbon in the alga. Sucrose does not accumulate in significant quantities. The amount of carbon partitioned either into starch or growth varies during the 12 hour light/12 hour dark cell cycle. Starch is accumulated at the beginning and at the end of the light period while a net breakdown is observed in the middle of the light period and in the dark. In contrast, nonsynchronized cells accumulate starch all the time in the light which suggests that carbon partitioning is controlled by the cell cycle. Labeled bicarbonate is incorporated into starch even at times when the total intracellular level of starch is decreasing. This indicates a turnover of the starch pool in the light with synthesis and degradation occurring simultaneously and at different rates.

Journal Article↗
PubMed1987

Cultivation of Bowes melanoma cells in the Opticell system: influence of the addition of protein supplements to the serum-free medium on the production of plasminogen activator.

The influence of a protein-free and a protein-rich, supplemented serum-free medium on the production of plasminogen activator (t-PA) from Bowes melanoma cells was investigated in the Opticell culture system and compared to tissue culture flask cultures. In the presence of medium supplements metabolic activity and t-PA production were favoured in both systems. The addition of supplements was apparently more effective in the Opticell than in flask cultures, because t-PA activity obtained in the Opticell was 2-3 times higher in protein-rich medium, but 2 times lower in unsupplemented medium than in flasks. These results indicate that the protein content in a serum-free medium is important for product formation in the Opticell, and serum-free media which work at small scale in tissue culture flasks are not always suited for technical culture systems such as the Opticell but have to be adapted to them.

Biotechnology↗
PubMed1987

[Animal experiment studies of high frequency jet ventilation with a newly developed pneumatically controlled respirator].

The effects of high frequency jet ventilation (HFJV) were investigated in 12 mongrel dogs with normal lungs. A newly developed HFJV device with purely pneumatic regulation was used. In order to evaluate several ventilatory parameters, respiratory rate, breathing time quotient and jet emission pressure were varied. Thus, important ventilatory, hemodynamic and calculated values were recorded. Accordingly, HFJV is possible with the tested device under clinical conditions in the frequency range between 80 and 300/min, with a breathing time ratio of 1:21 to 1:1 and a driving pressure up to 0.4 MPa with an oxygen concentration of FiO2 = 0.21 to 1.0. Before clinical use, however, investigations on the damaged lung of the dog are necessary.

Animals↗
PubMed1985

Influence of beta-lactam antibiotics, fosfomycin and vancomycin on the adherence (hemagglutination) of Escherichia coli-containing different adhesins.

The adherence of Escherichia coli of certain adhesin types can be influenced by subinhibitory concentrations of beta-lactam antibiotics. Subinhibitory concentrations (1/4MIC) of those penicillin and cephalosporin compounds which lead to filament formation increase mannose-sensitive adhesion (MS+). Antibiotics with ovoid cell formation did not change or only slightly reduced MS+ adherence. Strains with mannose-resistant (MR+) adhesins were not affected by these antibiotics. Only azthreonam increased the adherence of both MS+ and MR+ strains. Vancomycin and fosfomycin reduced the adherence of all strains tested. The degree of change was strain and antibiotic specific. No relation could be detected between the changes of adherence and the changes of hydrophobicity under the influence of antibiotics. Electron microscopic investigation has not yet yielded an explanation of the observed phenomenon.

Adhesiveness↗
PubMed1985

[Phospholipase A2 inhibitors in hemorrhagic-necrotizing pancreatitis. Animal experiment evaluation of a new treatment concept].

In mongrel dogs with induced pancreatitis we studied the effects of the nonspecific phospholipase A2-inhibitors chlorpromazine, gabexate mesilate and CaNa2EDTA on the course of pancreatogenic shock and the intrapancreatic lysolecithin production. The local level of lysolecithine the metabolite of phospholipase A2 was lower in the treated than in the untreated control groups. Gabexate mesilate was the most active inhibitor. However, none of the drugs had a beneficial influence on hemodynamics, chlorpromazine made it even worse. Morphologically no difference was seen between the treated and untreated groups.

Acute Disease↗
PubMed1984

Dendritic membrane from insect olfactory hairs: isolation method and electron microscopic observations.

Sensory hairs from antennae of male saturniid moths (Antheraea polyphemus) were separated while deep-frozen by shaking antennal branches with glass beads. The hairs were collected through their differential adhesion to the surface of a petri dish. The yield, determined by the length of the isolated hair fragments, was about 38% of the estimated total hair length per antenna. The dendritic membrane was separated from the hair fragments by centrifugation through Sephadex and further purified by ultracentrifugation in sucrose buffers. Transmission electron microscopy was used to monitor the steps of the hair and membrane isolation and to investigate the membrane pellet. Some membrane vesicles bound cationized ferritin, thus indicating a negatively charged cell surface coat. Negatively stained membrane vesicles exhibited a pattern of repetitive substructures irregularly distributed over the vesicle surface. The units had a diameter of about 3 nm and a maximal density of 30,000/micron2.

Animals↗
PubMed1984

Somatostatin-containing cells in the extrahepatic biliary tract of humans.

We investigated the presence of endocrine cells in the human extrahepatic biliary system using the avidin-biotin-peroxidase complex method. Twenty gallbladders obtained during operations for cholelithiasis, large portions of three common bile ducts obtained during Whipple's procedure for carcinoma of the head of the pancreas, and 155 endoscopic transpapillary biopsy specimens taken during control endoscopy from patients who had had a previous endoscopic sphincterotomy were examined. Somatostatin-containing cells were found in the glandular epithelium of the ampulla of Vater and the bile ducts. Only the surface epithelium in the ampulla contained endocrine cells. All somatostatinlike immunoreactivity was confined to cells and could not be detected in nerves. No somatostatinlike immunoreactivity was found in the gallbladder. These findings reveal a morphologic basis to reported actions of somatostatin on bile flow.

Ampulla of Vater↗