PubMed Health⌕ Search

Biomedical subjects

M Reiter

Publications and source records attributed to M Reiter.

At least 19 recordsLinked to original sources
PubMed1992

McLeod syndrome: a distinct form of neuroacanthocytosis. Report of two cases and literature review with emphasis on neuromuscular manifestations.

McLeod syndrome was originally described on the basis of a specific blood group phenotype with weak expression of Kell antigens. This erythrocyte abnormality also causes acanthocytosis. The haematological findings are associated with abnormalities in other organ systems, including neuromuscular manifestations. A 51-year-old patient was followed up for 11 years. He presented with persistent muscle creatine kinase elevation and progressive heart disease and later developed a slowly progressive neuropathy and choreic movements. His younger brother presented with grand mal seizures, involuntary movements and high muscle creatine kinase when aged 43 years. Clinical myopathy was absent in both, yet muscle biopsy showed mild myopathic changes. The presence of a motor axonopathy was supported by electrophysiological findings. One brother also showed sensory axonopathy. The movement disorder suggested accompanying basal ganglia dysfunction. Earlier reports of McLeod syndrome are reviewed with respect to neuromuscular involvement. Absence of the Kx membrane protein seems to be the cause of this multi-system disorder.

Acanthocytes↗
PubMed1992

Flow cytometry and two-dimensional electrophoresis (2-DE) for system evaluation of long term continuous perfused animal cell cultures in macroporous beads.

Immobilization of r-CHO cells at high density using macroporous polyethylene carriers in a modular fluidized bed reactor is demonstrated. Specific growth rates of the cells are measured by incorporation of BrdU. At a cell density of about 10(8) cells/ml a stable growth rate of 0.004 h-1 was established. Total release of proteins into the culture supernatant during protein-free perfusion was analyzed by 2-DE in various phases of the long-term culture showing very similar patterns indicating a constant pattern of gene expression.

Animals↗
PubMed1992

Determination of division rates of rCHO cells in high density and immobilized fermentation systems by flow cytometry.

As most high density and immobilized fermentation systems do not allow the direct quantitative determination of cell density, two flow cytometric methods (the determination of incorporation of bromodeoxyuridine into newly synthesized DNA and the increase in mitotic cells by colchicine blockage) were evaluated as to their suitability to measure true division rates of cells in bioreactors. The BrdU method gave division rates identical to the growth rates measured by cell count, while the colchicine block method gave values that were lower and varied with the cell line. This is due to the cytotoxicity of colchicine and makes a calibration of the method for each cell line necessary. Both methods have been successfully used to measure division rates of rCHO cells immobilized in an alginate matrix as well as in macroporous carriers in a fluidised bed system and in dialysis culture.

Animals↗
PubMed1992

Two-dimensional electrophoresis as a tool for control of quality and consistency in production systems using animal cells. Two-dimensional electrophoresis in animal cell culture technology.

A nonrecombinant human melanoma cell line and recombinant chinese hamster ovary (CHO) cells were used as examples for long-term in vitro cultivation in protein-free media. The method used to monitor the consistency of protein release by these mammalian cells was two-dimensional electrophoresis with immobilized pH gradient. Secreted proteins from a melanoma cell line cultivated in a continuous fermentation system over a period of 22 months were monitored. Two-dimensional patterns of secreted proteins were compared and the stability of their composition was determined over a period of nearly 14 months, with significant pattern variation being observed after 14 months. The protein pattern from this extended in vitro culture was compared to those of the very same melanoma cell line recultivated after being frozen in liquid nitrogen for more than 2 years. Due to the high resolution of complex polypeptide mixtures and the possibility to detect even minor differences in the composition of protein patterns, we propose the two-dimensional electrophoresis as a tool for quality assessment in animal cell culture technology.

Animals↗
PubMed1992

[Validation of the gas exchange monitoring function of the Engström Elvira respirator].

Gas exchange monitoring (GEM) has only recently become available for routine use on ventilated patients. Engström has introduced a new concept of integrated gas exchange monitoring within the Elvira respirator, optionally combined with an external CO2 monitor. The following paper describes a laboratory validation of a prototype of this device with regard to the influence of respiratory variables within their specified ranges: FIO2 0.2-0.6, FIO2-FEO2 (DFO2) 0.02-0.05, FECO2 0.02-0.05, VI 5-20 l/min, p 10-60 mbar, respiratory rate 7-29, VT 500-2,000 ml, inspiratory flow 25-90 l/min, relative humidity 5% and 55%. VO2 and VCO2 (100-700 ml/min) were simulated by gas dilution at a respiratory quotient of 1 using a 'bag-in-the-bottle' test lung for 48 test situations. Two reference measurements per test situation were carried out by mass spectrometry and wet-gas spirometry. The Elvira GEM function uses a self-calibrating fuel cell for FO2 detection, an external infrared CO2 monitor (Eliza) for FECO2 measurement, and differential pressure detection on a venturi principle for inspiratory flow measurement. VI measurement necessitates the use of the Haldane transformation for VO2 and VCO2 calculation. The VO2 (VCO2) repeatability coefficient (2 s) for the reference method was 5.6 (5.5) ml/min compared to 10.3 (10.35) ml/min for the GEM function. The mean relative methodical difference for VO2 (VCO2) was +19% (+4.1%) with limits of agreement (+/- 2 s) of +/- 13% (+/- 8.7%). The systematical difference for VCO2 as well as the variability within different test situations was in an acceptable range for clinical measurement.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation Studies as Topic↗
PubMed1991

Sigma S, a measure of reactive sulfur groups of immunoglobulin G, is a sensitive tumor marker discriminating different stages of breast cancer.

Sigma S is a measure of the disulfide bonds and free thiol groups of serum immunoglobulin (Ig) G, as determined by the reaction with dithionitrobenzoate. Significant decreases of sigma S previously were detected in malignant compared with benign diseases of various organs. This study shows the application of sigma S for the diagnosis of breast cancer. The following results were obtained. First, 132 patients with benign breast diseases showed a sigma S of 1.48 +/- 0.29 (standard deviation) per mole IgG; this was not different from 1.51 +/- 0.36 found in 182 controls. In contrast, IgG from 198 patients with primary breast carcinoma of all four stages (tumor-node-metastasis system) gave a sigma S of 1.22 +/- 0.29, a significant (P less than 0.0001) decrease of sigma S from benign to malignant breast disease. Second, sigma S values of single Stages I, II, III, and IV, were 1.27 (n = 59), 1.23 (n = 83), 1.19 (n = 35), and 1.10 (n = 21), respectively, each significantly different from sigma S in benign disease and showing a decreasing trend with increasing tumor progress. Differences were significant between Stages I and IV (P less than 0.025) and II and IV (P less than 0.05). Third, 63% of Stage I breast carcinoma patients had sigma S values below a critical threshold of 1.38. This serum positivity rose to 90% in Stage IV. These values exceeded those reported with other tumor markers. The overall power of sigma S to distinguish between benign and malignant breast disease had a specificity of 61% and a sensitivity of 78%. Early stages (I and II) of breast cancer could be distinguished from benign diseases with 64% specificity and 69% sensitivity. Advanced Stage IV could be discriminated from early Stages I and II with 55% specificity and 71% sensitivity. Thus, the analysis of sigma S may significantly contribute to the surveillance of patients with breast cancer.

Adult↗
PubMed1991

Modular integrated fluidized bed bioreactor technology.

We describe the design and demonstrate the application of a modular integrated fluidized bed bioreactor system. Basically the system is a reactor vessel equipped with an extending cylinder and a liquid distributor plate. Instead of an external recirculation loop, as used in existing fluidized bed systems, a low shear stress impeller is used as the recirculation pump. The system has several unique features, such as modular exchangeable elements, efficient oxygenation and the option of operating as a stirred tank-, a packed bed- or a fluidized bed reactor. An example of a fluidized bed run using CHO-K1 cells is shown. Under standard culture conditions a 100-fold increase in cell density (up to 1.2 x 10(8) cells/ml) was achieved.

Animals↗
PubMed1990

High density microcarrier culture with a new device which allows oxygenation and perfusion of microcarrier cultures.

A novel system useful for aeration and cell retention in continuous perfused microcarrier cultures is described. The system is based on a vibrating cage that separates cells and microcarriers from the oxygenation chamber and allows gas bubble free oxygen transfer. In the cultivation of monkey kidney cells (VERO) on gelatin coated microcarriers, using different concentrations (5, 10 and 15 g Cytodex 3/liter) cell densities up to 10(7) cells per ml were obtained. The described system is scaleable.

Animals↗
PubMed1990

A continuous multistage roller reactor for animal cell culture: 1. Patterns of growth, production and catabolism of a murine hybridoma.

A Tubular Liquid Film Reactor was designed as a model system to transfer a batch culture kinetic to a continuous cascade. Cell density, product formation and substrate consumption rates were followed during fermentation at two dilution rates. In spite of the high dilution rates effective in each segment by itself high cell densities of up to 10(7) cells/ml were achieved due to cell sedimentation. The model character of the reactor was taken to determine critical values of substrate concentrations that influence production rates and result in an adaptation of metabolism.

Alanine↗
PubMed1990

The use of macroporous gelatin carriers for the cultivation of mammalian cells in fluidised bed reactors.

A fluidised bed system for the cultivation of mammalian cells on a new type of macroporous gelatin microcarrier is described. The volumetric cell densities achieved under controlled conditions for two 'standard cell lines' (VERO, CHO) were one order of magnitude higher compared to conventional techniques using spherical microcarriers. The system can be potentially used for both anchorage dependent and independent cells.

Animals↗
PubMed1979

The influence of (+)-propranolol on the inotropic effect of dihydro-ouabain in relation to stimulation frequency.

1. The influence of (+)-propranolol, 10(-6) to 4 x 10(-5) mol/l, upon the positive inotropic effect of dihydro-ouabain was studied on guinea-pig papillary muscle. At 1 Hz, negative inotropically effective concentrations of (+)-propranolol decreased the inotropic effectiveness of the glycoside. 2. For equivalent diminution of the basal force of contraction, either by reduction of stimulation frequency or by increasing concentrations of (+)-propranolol, a similar decrease in the inotropic effectiveness of dihydro-ouabain was observed. In contract, reduction of [Ca2+]o had almost no effect on the effectiveness of the glycoside. 3. The inhibitory effect of (+)-propranolol on the inotropic effectiveness of dihydro-ouabain declined with reduction of stimulation frequency. At any stimulation frequency tested, the inhibitory effect of (+)-propranolol was proportional to the effect of a reduction of that particular frequency to the rested-state condition in the absence of (+)-propranolol. 4. The results are consistent with the hypothesis that the inhibition of the excitation-coupled sodium influx by (+)-propranolol is the cause of its inhibiting effect on the effectiveness of dihydro-ouabain.

Animals↗