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Biomedical subjects

M R Müller

Publications and source records attributed to M R Müller.

At least 73 records · Page 4Linked to original sources
PubMed1989

Clinical total artificial heart bridging: Viennese strategy and experiences.

Worldwide the clinical use of total artificial hearts (TAH) for bridging the time until heart transplantation (HTX) has become part of HTX programs. At our clinic, TAH bridging has been performed in five deteriorating HTX candidates since 1986. Four patients suffered from dilative CMP and one patient from a large anterior wall infarction. Three times the ellipsoid heart and twice the Berlin TAH were implanted. After TAH implantation, the conditions of all patients improved. The accompanying dysfunctions of kidneys and other vital organs, which were due to cardiogenic shock, could be restored in the three patients who underwent subsequent HTX. Bridging periods lasted from 9 to 13 days. Two patients, however, could not be transplanted because of infection. Although three patients could be bridged until transplantation and were in good clinical conditions, the longest survival following two-stage HTX was 40 days. In the future, complications like infection, bleeding, and transplant rejection have to be prevented to improve the long-term results of Viennese TAH bridging.

Aged↗
PubMed1989

Control of the total artificial heart: new aspects in human versus animal experience.

Control strategies for total artificial heart application have generally been based on experience with healthy animals. Human patients in a bad state of health who have impaired organ functions and who are subjected to intensive care procedures can develop atypical hemodynamic behavior. In these patients, both unstable and hyperstable behavior of the vascular resistance were observed. Therefore, regulation of cardiac output (CO) by pressure parameters only was avoided and CO was adjusted to obtain an appropriate O2-utilization (O2U). Intending to keep the O2U within ranges of 20-25%, we obtained cardiac indexes between 3.3 and 4.4 L/m2/min (CO 6-8 L/min), which is higher than other cardiac indexes reported. A CO of 10.5 L/min was even necessary to obtain an O2U of 30% in a septic patient. This strategy caused a stable driving management and led to a rapid hemodynamic stabilization and general improvement of the patients' condition. Results indicate that it is also very important to monitor metabolic parameters for appropriate driver adjustment as well, especially in the early postoperative phase, and that O2-U is a sensitive and useful parameter for this purpose.

Animals↗
PubMed1989

[Air embolism in the sitting position. Oxygen/nitrogen versus oxygen/laughing gas].

UNLABELLED: Venous air embolism (VAE) is a well-known complication of neurosurgical procedures performed in the sitting position. Nitrous oxide (N2O) intensifies the hemodynamic alterations conditioned by VAE. Therefore the administration of N2O must be discontinued immediately if VAE occurs. Nevertheless, it is still not clear whether N2O should be avoided in such operations as a general policy. The aim of the present study was to investigate the incidence and severity of VAE with O2/N2 as opposed to O2/N2O anesthesia. METHODS. In all, 42 patients (19 men, 23 women) aged 23-80 years were investigated in a randomized order. In all cases an intracranial operation was carried out with the patient in the sitting position. The anesthesiologic management was uniform: modified neuroleptanalgesia (fentanyl, flunitrazepam, droperidol), relaxation with pancuronium, endotracheal intubation, moderate hyperventilation (PaCO2 30-35 mmHg) without PEEP. Half (21) of the patients (group 1) were ventilated with O2/N2 (1:1) and the remaining patients (group 2) with O2/N2O (1:1). Heart rate (HR) arterial blood pressure (AP), central venous pressure (CVP), end-tidal CO2 tension (PE'CO2), and body temperature were monitored continuously. Arterial blood gases were checked once per hour at least. VAE was signaled by changes in the ultrasonic Doppler sounds or a rapid decrease in the end-tidal CO2 tension. The diagnosis of VAE was confirmed by aspirating air bubbles through the right atrial catheter. A vacuum-driven device was used to suction off the embolized air and measure the aspirated air volume. Pulmonary gas exchange was defined by the arterial to end-tidal CO2 difference (PaCO2 - PE'CO2) and by the alveolar arterial O2 quotient (PAO2 - PaO2/PAO2). If a VAE was recognized N2O administration was stopped immediately and ventilation was continued with pure oxygen. Postoperatively all patients were ventilated. RESULTS: The incidence of VAE was similar in both groups: VAE occurred in five patients in group 1 and in six patients in group 2. In isolated cases distinct increases in the CO2 difference (PaCO2 - PE'CO2) or the O2 quotient (PAO2 - PaO2/PAO2) resulted, with no significant difference between the groups. In patients with VAE the aspirated gas volume (median 6.0 ml in group 1, 75.5 ml in group 2; P less than 0.01) and the duration of aspiration (median 5.0 min in group 1, 22.5 min in group 2; P less than 0.05) were significantly different in the two groups. HR was significantly lower in group 2 1 and 4 h after the beginning and at the end of the operation. MAP was significantly lower in group 2 3 and 4 h after the beginning and at the end of the operation. CVP was significantly higher in group 2 3 h after the start of the operation. The total dose of fentanyl, flunitrazepam and droperidol administered was higher in group 1 than in group 2 (P less than 0.05). The duration of postoperative ventilation was similar in both groups.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1989

[An increase in intracranial pressure following fentanyl].

We report an unusual fentanyl-induced reaction in an 8-year-old boy who had to be sedated and hyperventilated because of a severe head injury. Following the intravenous administration of a bolus of fentanyl, the intracranial pressure rose markedly for about 10 min. Simultaneously, the arterial blood pressure fell and heart rate increased, critically reducing the cerebral perfusion pressure temporarily. This reaction could be due to histamine-induced vasodilation.

Child↗
PubMed1988

[Action of various growth factors on bone marrow cultures in acute myeloid leukemia (ALM)].

In an attempt to detect residual leukemic cells during remission, we examined differences in the stimulatory capacity of colony stimulating factors (CSF) added to agar cultures of AML patients at diagnosis/relapse (group I) and in remission (II), or of normal controls (III). Supernatant from the human bladder carcinoma cell line 5637 and human recombinant granulocyte-macrophage-CSF were compared with supernatant from human placenta as standard. Group I showed wide patient-to-patient variations. The stimulatory capacity of the 3 CSF produced significant differences within groups II and III, but not between those groups. In conclusion, our comparative investigations do not reveal residual leukemic cells in the marrow of AML patients in remission.

Adolescent↗
PubMed1988

[General surgical interventions in heart surgery patients].

Due to the rapid development in cardiac surgery it is obvious that we now find more patients after heart operations requiring major noncardiac surgery. Knowledge concerning the special problems in treatment of patients with prior cardiac surgery is indispensable to guarantee a low perioperative risk. It is of great consequence, what kind of cardiac disease we are dealing with, whether the cardiac defect could be corrected partially or totally and how the cardiac index has been finally. We discuss the situation after different cardiac operations including coronary bypass grafting, heart valve surgery and heart transplantation. Several multi-case studies could prove that after successfully performed bypass grafting a coronary heart disease does not improve the perioperative risk of following surgical treatment. Some authors recommend a 6 month interval after coronary heart surgery. A higher risk for ventricular arrhythmias can be found in patients with a manifest coronary heart disease following operative revascularisation. Special comment is given to the recommended treatment of the different stages of coronary heart disease in respect to the time course with noncardiac surgery. General surgery after heart valve replacement can be complicated by the appearance of dysrhythmia and arrhythmia, left heart failure, tendency to bleed and higher risk of infections. Patients with a transplanted heart need special care on the part of narcosis and asepsis.

Heart Diseases↗
PubMed1987

[Diagnosis of peritoneovenous shunt occlusion].

Reaccumulation of ascitic fluid after peritoneovenous shunt implantation demands accurate diagnostic procedure. Between 1973 and 1985 81 peritoneovenous shunts have been implanted at the IInd Surgical Department of the University of Vienna. In the same time 34 reoperations in 17 patients have been performed for reasons of shunt-dysfunction. Besides thorax x-ray, diagnosis was established in 11 cases by means of Doppler ultrasound investigation, in 26 cases by technetium scan and in 15 cases by shunt angiography. Shuntography proved to be the method of choice, with no false results. Doppler ultrasound results were unclear in a high percentage, thus this method is not used any more.

Ascites↗
PubMed1987

Prognostic significance of agar and liquid cultures in AML patients before treatment, early postinduction and in remission.

In the present study, the growth and differentiation capacity of myeloid leukemic cells in agar and liquid cultures have been investigated in relation to their prognostic significance for treatment outcome and early detection of relapse. Prior to induction therapy, leukemic cells failed to differentiate and the colony or cluster number did not correlate with response to treatment. Seventeen to 42 days after induction, patients with BM cells producing greater than 10 colonies or greater than 30 clusters resp. had a high likelihood of achieving a complete remission. Cells from refractory patients had a significantly impaired differentiation capacity. During remission, a colony number greater than 50 was significantly associated with a high probability to remain in further remission for greater than 3 months. An impaired differentiation was significantly associated with the likelihood of relapsing within 3 months. In the light of these results, agar and liquid cultures appear to be useful for monitoring the effect of induction chemotherapy and detecting patients likely to relapse.

Agar↗
PubMed1985

Synthesis and secretion of the human vitamin B12-binding protein, transcobalamin II, by cultured skin fibroblasts and by bone marrow cells.

Human skin fibroblasts and bone marrow cells were tested for their ability to synthesize the cobalamin-binding protein transcobalamin II. Cobalamin binders secreted in the media of cultured fibroblasts and of dextran-sedimented bone marrow cells in liquid culture could be identified as transcobalamin II on the basis of immunological, electrophoretical and chromatographical identity with serum transcobalamin II. The net secretion of transcobalamin II increased linearly with time of culture, up to 30 days after confluence. The reversible inhibition of transcobalamin II secretion by cycloheximide demonstrated that human fibroblasts are capable of de novo transcobalamin II synthesis. Addition of cyanocobalamin to the fibroblast culture medium induced a reduction of transcobalamin II net secretion, most likely due to preferred uptake of transcobalamin II saturated with cobalamin, as opposed to unsaturated protein. Addition of lysozymal enzyme inhibitors, ammonium chloride and chloroquine, resulted in a markedly increased secretion of transcobalamin II. In the culture medium of fibroblasts, obtained from two transcobalamin II-deficient patients, functionally deficient transcobalamin II was demonstrated on the basis of strongly reduced secretion of immunoreactive transcobalamin II, and the absence of apotranscobalamin II. Individual phenotypes in the culture media of the fibroblasts and bone marrow cells were identical to the corresponding serum transcobalamin II types.

Bone Marrow↗
PubMed1985

Inhibition of granulopoiesis in vivo and in vitro by beta-lactam antibiotics.

beta-Lactam antibiotics can induce severe neutropenia by a hitherto unknown mechanism. Fifty cases of beta-lactam antibiotic-induced neutropenia (less than 1,000 neutrophils/mm3) from 17 hospitals were analyzed and compared with 140 literature cases. The incidence of neutropenia was 5%-greater than 15% in patients treated for greater than or equal to 10 days with large doses of any beta-lactam antibiotic but less than 0.1% with shorter duration of therapy. In greater than 95% of cases recovery occurred between one to seven days after withdrawal of beta-lactam antibiotics. Bone marrow aspirates were characterized by a lack of well-differentiated myeloid elements in the presence of numerous immature granulocyte precursors. Nine penicillins and eight cephalosporins inhibited in vitro granulopoiesis in a dose-dependent manner. There was a good correlation between the inhibitory capacity of beta-lactam antibiotics in vitro and the doses inducing neutropenia in vivo. These observations may be relevant for therapy in the granulocytopenic patient.

Agranulocytosis↗
PubMed1983

Penicillin-G degradation products inhibit in vitro granulopoiesis.

38% of penicillin-G in solution decays at 20 degrees C within 24 h, 50% at 37 degrees C and 66% within 3 h at 56 degrees C. These degraded penicillin-G solutions strongly inhibit growth and maturation of granulocytic stem cells in vitro. Inhibitory concentrations are in the range obtainable with high dose penicillin therapy in vivo. No cytotoxicity of degraded penicillin solutions on bone marrow cells was seen over 24 h. It is suggested that penicillin-G degradation products are responsible for severe granulocytopenia observed after high dose penicillin-G therapy.

Bone Marrow↗
PubMed1982

Cellular aggregates in bone marrow cultures of patients with acute myeloid leukemia.

We describe the incidence and morphology of cellular aggregates which may develop in 8 day bone marrow (BM) cultures of patients with acute myeloid leukemia (AML). Aggregates formed in at least one BM culture from 50% (20/39) of the AML group. They developed irrespective of the patient's status (i.e. stages M1-M4), FAB type, and presence of colony stimulating factor (CSF). All aggregates were composed of macrophages, plasma cells, and cells of the myelocyte series surrounding a core of adipocytes and collagen fibrils. The percentage of blasts and promyelocytes in the plated BM aspirate governed the final composition of the aggregate. Patients in Stages M3 or M4 with FAB types M1 or M2 formed aggregates with a high proportion of myelocytic cells; aggregates of all other AML patients were composed predominantly of macrophages and plasmacytes. Aggregates appeared to form as a result of attraction of cells in the medium toward the stroma cell core. Furthermore, the development of aggregates in the absence of exogenous CSF, suggested that stromal cells excreted a factor with CSF-like activity. The results indicate that cellular aggregates in AML-BM cultures reflect the important role of BM stroma in creating microenvironments which enhance the development of hemopoietic stem cells.

Bone Marrow↗
PubMed1977

Biologic activity of transfer factor tested in vitro with cord blood lymphocytes.

Cord blood lymphocytes, generally believed to be immunologically uncommitted, were used for investigating the possible conversion by transfer factor (TF) of non-immune to immune lymphocytes in vitro. TF was prepared from pooled buffy coats of normal blood bank donors by ultrafiltration and lyophilization, and it ability to influence lymphocyte transformation was assessed by measuring increases in 3H-thymidine uptake into DNA after stimulation with purified protein derivative of tuberculin and/or streptokinase-streptodornase in 23 experiments with cord blood and 15 adult controls. TF stimulated cord blood lymphocytes nonspecifically when added to the medium alone. In the presence of antigen, TF acted in a synergistic, antigen-dependent way with either amplifying or inhibitory effects in adult good responders. These effects were negligible in adult low responders and in cord blood. From our observations no specific conversion of lymphocytes by TF in vitro can be deduced.

Adult↗
PubMed1976

Production of migration inhibitory factor and blast cell transformation by cord blood lymphocytes.

Cord blood lymphocytes from 29 normal infants of 28-41 weeks gestational age were tested for blast cell transformation and migration inhibitory factor (MIF) production. Cultures were stimulated with phytohemagglutinin (PHA) and purified protein derivative of tuberculin (PPD) for transformation; with purified PHA, soluble and insoluble concanavalin A as well as PPD for MIF production. 3H-thymidine incorporation by cord blood and by adult lymphocytes were similar in magnitude after PHA stimulation, but differed significantly after PPD stimulation, with negligible increased incorporation by the former and marked increased incorporation by the adult lymphocytes. With the exception of PPD, the stimulating agents used led to MIF production by cord blood lymphocytes. No dissociation was observed between proliferative response and MIF production. Both functions seem to be fully developed at birth.

Concanavalin A↗
PubMedDate not supplied

The effects of interferon on granulopoiesis in vitro.

Colony formation by myeloid progenitor cells (CFU-c) in agar was inhibited to the same extent by heterogeneous human leucocyte IFN (IFN-Le) and 2 different cloned IFN-alpha 2 preparations, but approximately 10 times less by cloned IFN-alpha 1; cluster formation remained unaffected by any of the interferons. An anti-proliferative effect is suggested by both lower cell yield and DNA synthesis in IFN containing liquid cultures. Incubation of cells with IFN for 18 h prior to plating with colony stimulating factor (CSF) reduced colony formation, indicating an altered responsiveness of CFU-c to CSF. In IFN treated cultures no consistent block of morphological differentiation occurred, but granulocyte alkaline phosphatase activity was reduced. Thus, IFN may play a modulatory role on functional markers. Our results indicate that the effects observed with heterogeneous preparations are due to IFN and not to impurities and that various differentiation parameters are unequally affected by IFN.

Alkaline Phosphatase↗
PubMedDate not supplied

Non-dairy lactic fermentations: the cereal world.

Sourdough is the foremost cereal fermentation performed in a variety of technologies with almost any cereal. The lactobacilli studied most intensely include Lactobacillus sanfranciscensis, L. reuteri and L. pontis isolated from traditional and modern rye and wheat fermentations. Molecular biology tools are available for their rapid identification and monitoring throughout a process. The currently available insight on their metabolism can be used to explain their prevalence in this environment and their interactions. Key genes of the sugar degradation pathway were cloned and characterised from L. sanfranciscensis. In addition some strains were found to have special properties including the production of antagonistic compounds or the adhesion to human intestinal cells.

Bacterial Adhesion↗