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Biomedical subjects

M Otto

Publications and source records attributed to M Otto.

197 records · Page 11Linked to original sources
PubMed1976

A comparison of the influence of potassium and ammonium ions on the phosphofructokinases from rabbit muscle and rat erythrocytes.

Phosphofructokinases from rat erythrocytes and rabbit muscle have been compared in their kinetic behavior with respect to monovalent cation activation and ATP inhibition. Both ammonium and potassium ions affect the muscle enzyme in a two-fold manner: they act both as activators and effectors. On the other hand only ammonium exerts the two-fold effects on the erythrocyte enzyme, while the potassium ions activate without affecting cooperativity. The lower ATP inhibition of muscle phosphofructokinase may be partially explained by the action of potassium ions on the cooperative behavior of the enzyme. The differences between the phosphofructokinases from erythrocytes and muscle in the potassium type-II activation and ATP inhibition represent an organ specifity. Furthermore, the inhibition constants for 2, 3-bisphosphoglycerate differ by 10-fold between the two enzymes.

Adenosine Triphosphate↗
PubMed1975

On the influence of fructose-6-phosphate, ammonium, ATP and AMP on the conformation of the phosphofructokinase from rabbit muscle.

By means of circular dichroism measurements in the range from 210-240 nm and 250-300 nm it is shown that conformational changes of the phosphofructokinase from rabbit muscle correlate with the action of effectors on the enzyme. The postulated active and inactive states differ in the secondary structure. Addition of activators causes a conformational change which is interpreted as the transition of the inactive into the active state. At 210-240 nm no reversion could be observed but at 250-300 nm there are some indications for at least partial reversion.

Adenosine Triphosphate↗
PubMedDate not supplied

Harman (1-methyl-beta-carboline) in blood plasma and erythrocytes of nonalcoholics following ethanol loading.

Eleven subjects having no history of substance abuse or dependence who agreed to abstain from alcohol for one week prior to the investigation were selected to participate in the present study. On two occasions, separated by four to six weeks, blood was drawn over an 8-hour period (0, 0.5, 1, 2, 4 and 8 hours). On the first occasion, subjects were given an oral dose of ethanol (1 g/kg) after the first blood sample was drawn (ethanol-loading condition). On the second occasion no ethanol was administered (control condition). On both occasions no detectable harman was found in the plasma of subjects. In the control condition harman was detected in the erythrocytes of 7 subjects which remained relatively stable over time. In the ethanol-loading condition, however, a time-dependent increase of harman in the erythrocytes was observed. The concentration of ethanol, acetaldehyde, and erythrocyte-harman showed a parallel trend over time. These findings demonstrate an increased level of harman following ethanol loading in humans.

Acetaldehyde↗
PubMedDate not supplied

ABC transporters of staphylococci.

Some members of the genus Staphylococcus are important human pathogens, such as Staphylococcus aureus and Staphylococcus epidermidis. ATP binding cassette (ABC) transporters of pathogenic staphylococci are often responsible for antibiotic resistance and for the uptake of essential solutes and are therefore being considered as targets for novel antistaphylococcal drugs. Other ABC transporters are involved in the biosynthesis of a special class of peptide antibiotics, the lantibiotics, and in self-protection of the producer against them.

ATP-Binding Cassette Transporters↗
PubMedDate not supplied

Endothelial cell cultures as a tool in biomaterial research.

Progress in biocompatibility and tissue engineering would today be inconceivable without the aid of in vitro techniques. Endothelial cell cultures represent a valuable tool not just in haemocompatibility testing, but also in the concept of designing hybrid organs. In the past endothelial cells (EC) have frequently been used in cytotoxicity testing of materials, especially polymers, used in blood-contacting implants, as well as for investigating seeding technologies for vascular prostheses. At present the exponential development both in theory and practice of cell and molecular biology of the endothelium offers great promise in the biomaterial field. Up until now this EC research field has mostly been non-biomaterial orientated. Nevertheless, the relevance for biomaterial research is apparent. Four aspects will be concisely reviewed under the headings inflammation, with special reference to cell adhesion molecules (CAMs) and cytokines, angiogenesis, focusing on the healing response, signal transduction, presenting examples from cytokine- and metal ion-induced up-regulation of genes coding for CAMs, and, finally, endothelial functionality, with emphasis on the principal characteristics of the physiological endothelial phenotype. Finally, the application of these fields to three foci of biomaterial research will be discussed, emphasizing the role of EC culture techniques in controlling the host response to biomaterials (microvascular EC), controlling EC functionality (promoting positive effects and down-regulating negative effects), and tissue engineering (integration of EC into hybrid organs/biosensors). The need for more co-culture and three-dimensional models will be stressed and data from the authors' laboratory presented to illustrate these principles.

Journal Article↗
PubMedDate not supplied

Laparoscopic operative technique for adrenal tumors.

BACKGROUND AND OBJECTIVES: Laparoscopy has acquired an unquestionable position in surgical practice as a diagnostic and operative tool. Recently, the laparoscopic approach has become a valuable option for adrenalectomy. This paper reports, in detail, our experience of laparoscopic adrenalectomy performed for adrenal tumors. METHODS: We performed 12 laparoscopic adrenalectomies from October 29, 1997 to October 31, 1998. The technique of laparoscopic adrenalectomy is described thoroughly in all relevant details for either left or right-sided adrenal lesions. RESULTS: The presented technique of laparoscopic adrenalectomy in all 12 cases provided good and relatively simple exposure of the immediate operative area. All relevant vascular elements were safely controlled, adrenal tumors could be successfully removed, and adequate hemostasis was achieved. No intraoperative or postoperative complications were observed. CONCLUSIONS: Laparoscopic adrenalectomy is a safe alternative to open surgery and is preferred for most patients because of shorter postoperative hospital stay and less postoperative discomfort.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

[Recanalization of occlusion of the peripheral segment of the femoral artery by the Kensey method].

The aim of the presented study was to analyse the surgical technique and results of recanalization of the peripheral segment of iliac artery with Kensey's technique. Altogether 16 patients were operated. Arterial patency was observed in 14 patients immediately after surgery. This number decreased to 11 after a 3-month follow-up. Complications in the form of perforation of the arterial wall, hemorrhage at the site of puncture and thrombotic lesions in the reconstructed arterial channel were seen in 4 cases. Authors' own experience suggests that Kensey's technique together with laser surgery are the treatment of choice in case of iliac arterial occlusion in patients, in whom classic surgery is contraindicated.

Adult↗
PubMedDate not supplied

[Imipenem in the treatment of patients with severe surgical infection].

The clinical efficacy and safety of intravenously administered imipenem/cilastatin in the treatment of 45 patients with severe bacterial septicemia due to intra-abdominal abscesses, respiratory and urinary tract as well as skin, soft tissue and bone infections was studied in the prospective and open trial. The in vitro antimicrobial activity of imipenem has been assessed on the basis of 909 bacterial strains isolated from patients treated and non-treated with imipenem/cilastatin. Among them were 526 Gram-negative, 370 Gram-positive aerobic bacteria and 13 Gram-negative anaerobic bacteria (Bacteroides sp.). Pathogen susceptibility to imipenem was determined with a disc-diffusion technique using Merck, Sharp Dohme sensitive discs containing 10 mcg of imipenem. Highly sensitive to imipenem were 96.8% of Gram-negative 82.7% of Gram-positive aerobic bacteria and 100% of Bacteroides sp. All patients, in whom evident foci of infection e.g. intra-abdominal abscesses were discovered, were operated on. The dosage of imipenem/cilastatin ranged from 1.5 to 2.0 g/24 h. Clinical cure and bacteriological elimination was achieved in 39 (86.7%) of patients while 6 (13.3%) showed marked clinical improvement. Before and during therapy, aerobic and anaerobic cultures were taken from accessible sites. All specimens were worked up using conventional bacteriological techniques. Before during and after therapy, samples for hematology, biochemistry and urinanalysis were obtained. Adverse clinical effects were noted in 2 (4.4%) patients. One had nausea and vomiting which were probably related to rapid infusion and disappeared after increasing the administration time, and one had transient diarrhea. In conclusion, imipenem/cilastatin was a well tolerated and effective drug in the treatment of life-threatening surgical infections.

Adolescent↗