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Biomedical subjects

M Windisch

Publications and source records attributed to M Windisch.

68 records · Page 4Linked to original sources
PubMed1992

Results of the multicenter evaluation of a homogeneous immunoassay for digitoxin based on the cloned enzyme donor immunoassay technology.

We evaluated a CEDIA assay for the determination of digitoxin in serum on random access analyzers. The multicenter evaluation included studies on the analytical range, calibration stability and reproducibility of the new assay. Moreover, recovery in controls, transferability of results obtained in different laboratories, comparability with routine methods, and the effect of various interfering factors have been analyzed. Summarized the analytical performance was comparable to that of routine methods. The CEDIA Digitoxin assay represents an attractive alternative to established digitoxin immunoassays because it can be performed on random access analyzers, thus permitting the simultaneous determination of digitoxin and other serum analytes without sample splitting.

Digitoxin↗
PubMed1991

Acute effects of amiodarone on ultrastructure and electrical activity of isolated guinea pig hearts.

STUDY OBJECTIVE: The aim was to evaluate the effects of tissue concentration of amiodarone on ultrastructure and electrical activity in isolated spontaneously beating Langendorff perfused guinea pig hearts. DESIGN: Group 1: The influence of 10 microM amiodarone over a period of 1 h in a non-recirculated perfusate on conduction intervals, heart rate, creatine kinase concentration in the coronary effluent, coronary flow, and drug accumulation was determined. Group 2: Ultrastructural changes after 30 min and 60 min perfusion with amiodarone were examined. Group 3: Cardiac refractoriness was evaluated following 30 min and 60 min of perfusion with amiodarone. EXPERIMENTAL PREPARATIONS: Isolated hearts of guinea pigs (200-300 g) were used: group 1, n = 6 animals; group 2, n = 3 for each time span; and group 3, n = 6 for each time span. MEASUREMENTS AND MAIN RESULTS: A steady state for the effects of amiodarone on atrioventricular and intraventricular conduction [+31(SEM 5)%, p less than 0.01% +47(12)%, p less than 0.01, respectively] and on heart rate [-30(9)%, p less than 0.01] was reached after 15 min, and on His bundle conduction [+38(17)%, p less than 0.01] after 30 min. QT duration was not affected throughout the duration of the experiment. Cardiac refractoriness was significantly prolonged following 30 min perfusion with 10 microM amiodarone, and was further significantly increased following 60 min perfusion. Amiodarone tissue concentration increased to 365(39) nmol.g-1 wet weight, and this was accompanied by an increase in creatine kinase concentration in the coronary effluent. Coronary flow stayed constant throughout the whole experiment. At the end of the experiment electron microscopic examination of the myocardium of the left ventricle showed accumulation, fusion, and vacuolisation of mitochondria, and perinuclear oedema. CONCLUSIONS: These observations suggest that amiodarone, as well as exerting acute electrophysiological effects, creates ultrastructural changes which probably contribute to its effectiveness in arrhythmias caused by scarred myocardium.

Amiodarone↗
PubMed1986

Comparative study of cefamandole versus cephalothin as antibiotic prophylaxis for open heart surgery.

Cefamandole nafate and cephalothin sodium were administered as prophylaxis in a randomized, prospective study to 80 consecutive patients undergoing open heart surgery. The two groups matched well in age, sex, and type of operation. Postoperative infection developed in 2 of 40 patients (5%) in the cefamandole-treated group and in 11 of 40 patients (27.5%) in the cephalothin-treated group (p less than 0.01). The two patients in the former group had respiratory tract infections. There were no instance of endocarditis, mediastinitis or bacteraemia in any of the two groups. Both antibiotics were well tolerated with no adverse reactions. Cefamandole appears to be an effective and preferable prophylactic antibiotic for use during cardiac surgery.

Adolescent↗
PubMed1985

[The effect on oxidative metabolism in brain, liver and heart muscle homogenates of peptide derivatives and calf blood dialysates].

Three peptide preparations, derived from different proteins, and one protein free extract, produced by dialysis of calf blood, were tested. Typical effects of the individual preparations on oxidative metabolism could be shown. A comparable high stimulation of oxygen consumption of brain homogenates by 117 to 165% was measured after application of the peptide derivatives. One of them, the peptide enriched derivative, caused a high and not organ specific stimulation, increasing the oxygen consumption of brain, liver and heart muscle by 165, 203 and 202%, respectively, thus exceeding the effects of the other tested preparations. Extracts of calf blood, which showed maximal stimulation in liver homogenate (98%), led to rather small effects in brain homogenate (51%) compared with those induced by the peptide derivatives.

Animals↗
PubMed1985

[The effect and changes in oxygen consumption of rat brain homogenates: in vitro effect of a peptide derivative].

The effect of a peptide derivative (Cerebrolysin) on oxygen consumption of brain homogenates was investigated in 1-day-old, 1-, 2-, 3- and 4-week-old and 2-, 4-, 8-, 12- and 18-month-old rats. A rapid increase of respiration up to the fourth week could be demonstrated. From that time on the values decrease until the age of 1 year and remain constant till the age of 18 months. At this age oxygen consumption corresponds to that of 2-week-old rats and lies 41% below the high level found in 4-week-old animals. In vitro application of the peptide derivative stimulates respiration significantly in all groups. There is striking evidence for a maximal relative increase in extremely young animals up to 2 weeks of life and in rather old ones aged 12 and 18 months.

Aging↗
PubMed1985

[Modification of rat brain metabolism by long-term treatment with a peptide derivative].

Rats have been treated with a peptide derivative (Cerebrolysin) for 3, 5, 7 or 14 days. Investigations were made on cerebral protein and lactic acid concentration and on in vitro oxygen consumption of brain homogenates derived from treated rats. In all experiments treatment with the peptide derivative caused a significant decrease in cerebral lactic acid level and a gradual decrease in basal oxygen consumption of the brain homogenates correlated with duration of treatment. These effects could be observed after two different peptide derivative dosages, in differently aged animals and were always manifest and significant between the 3rd and the 7th day of treatment. The higher dosage of the peptide derivative (2.5 ml/kg body weight/d) caused a significant increase in maximal respiratory activity of brain homogenates after a further in vitro application of the derivative.

Amino Acids↗
PubMed1980

[Places and means of patient "dechronicization" in a Paris district].

The authors report their work with chronic patients in various institutions of their sector. They point out the importance of the proper training of nurses in order to facilitate counterattitudes. The varied treatment centers allow the observation of the numerous aspects that the patient presents. Two important moments of the treatment are stated: the patient's arrival and settling down and his leaving. For the aged patients, preventive and dechronification go together.

Chronic Disease↗
PubMed1979

Purification of human intestinal goblet cell antigen (GOA), its immunohistological demonstration in the intestine and in mucus producing gastrointestinal adenocarcinomas.

Goblet cell antigen (GOA) was purified from gastric signet ring cell carcinoma. It was immunogenic and was used to produced antisera which stained goblet cells of the small and large intestine and of intestinalized gastric mucosa by indirect immunological methods. Various types of gastric and colonic cancer contained GOA. These findings demonstrate a histiogenic relationship between intestinal goblet cells, various gastrointestinal cancers and associated premalignant conditions.

Adenocarcinoma↗
PubMedDate not supplied

Comparison of acute electrophysiological effects of amiodarone and its metabolite desethylamiodarone in Langendorff perfused guinea pig hearts.

During long-term treatment with amiodarone, slowing of conduction through the atrioventricular node, a prolongation of the QT-interval, and a prolongation of the atrial and ventricular myocardial refractoriness always developed. During short-term treatment, these effects were not found, except for depression of the AV-nodal conduction. This led to the suggestion that the electrophysiological effects of amiodarone during long-term treatment might be partly the result of the accumulation of its metabolite desethylamiodarone. Therefore, we examined the electrophysiological effects of amiodarone and desethylamiodarone on conduction and refractoriness in isolated spontaneously beating guinea pig hearts perfused by the method of Langendorff. Within 1 h of perfusion, desethylamiodarone caused a more pronounced prolongation of the AV-nodal, His-bundle, and intraventricular conduction intervals than did amiodarone. Desethylamiodarone, but not amiodarone led to a prolongation of the QT-interval. The refractoriness of sinoatrial-, AV-nodal conduction, and of the atrial myocardium were significantly more prolonged by amiodarone than by desethylamiodarone. Both compounds showed a comparable strong rate-dependent effect on AV-nodal refractoriness. The ventricular refractoriness was similarily prolonged by either compound. These results show that for the class-III effects (i.e., prolongation of repolarization period) observed under chronic treatment of amiodarone the metabolite desethylamiodarone may be responsible. Desethylamiodarone also exerts more pronounced effects on the fast-channel-dependent parts of the conduction system than does amiodarone, a fact indicated by a higher prolongation of His-bundle and intraventricular conduction.

Amiodarone↗
PubMedDate not supplied

Increased density of glutamate receptor subunit 1 due to Cerebrolysin treatment: an immunohistochemical study on aged rats.

Glutamate receptor subunit 1 (GluR1) is one of the four possible subunits of the AMPA-type glutamate receptor. The integrity of this receptor is crucial for learning processes. However, reductions of GluR1 are noticeable in the hippocampal formation of patients suffering from Alzheimer's disease. Such degradations presumably result in an impaired synaptic communication and might be causally linked to the neurodegenerative process in this cognitive disorder. The peptidergic drug Cerebrolysin counteracts cognitive deficits of patients affected by Alzheimer's disease. These findings are supported by experiments revealing neuroprotective and neurotrophic capacities of the drug. In order to examine the effect of the drug on the density of GluR1 in hippocampal formation 24-month-old rats were treated with either Cerebrolysin or its peptide fraction E021, or saline as a control. Spatial navigation of the animals was tested in the Morris water maze. Rat brain slices were stained immunohistochemically with a GluR1-specific antibody. GluR1 immunoreactivity was quantified using light microscopy and a computerised image analysis system. Cerebrolysin and E021 increased GluR1 density in most measured regions of the hippocampal formation in a highly significant way. These results correlate with the behavioural outcome, revealing an improvement in learning and memory of these rats after treatment with Cerebrolysin and E021.

Aging↗