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Biomedical subjects

M Windisch

Publications and source records attributed to M Windisch.

At least 55 records · Page 3Linked to original sources
PubMed1995

Effects of postnatal stimulation on the passive avoidance behaviour of young rats.

We examined the effects of stimulation on either postnatal days 1-7 or 21-27 on passive avoidance reaction (PAR) of young rats. Animals received tactile or visual stimulation for 10 min each day, and were trained on postnatal day 28 in a step-through apparatus using a footshock of 0.75 mA for 2 s. Retention was tested on five consecutive days beginning on day 29. Memory retention was measured for each rat 24, 48, 72, 96 and 120 h after the acquisition trial. Step-through latencies to enter the dark compartment, time spent in the illuminated compartment and number of crossings of the light beam were recorded up to 200 s. Rats that received tactile or visual stimulation during the 4th postnatal week displayed significantly lower PAR latencies, a shorter stay in the illuminated compartment and a higher number of crossings of the light beam compared to rats treated during the 1st postnatal week. The untreated control group showed a rapid decline of PAR latencies. All experimental groups remained in the illuminated compartment longer and showed PAR latencies well above those of the control group. The differences became more pronounced when visual stimulation in the first postnatal week was used. The number of crossings of the light beam was significantly reduced by the treatment, with the exception of the experimental group stimulated visually in the 4th week. The behavioural changes induced by tactile or visual stimulation have a long-lasting effect in coping with a stressful task.

Animals↗
PubMed1994

Determination of traces of pyrethrins and piperonyl butoxide in biological material by high-performance liquid chromatography.

A liquid chromatographic method for the determination of pyrethrins and of the synergist piperonyl butoxide in human plasma after C18 solid-phase extraction is described. UV detection was found to be sensitive enough to determine concentrations far below the limit of toxicity. With respect to future investigations concerning studies in biological materials, a column-switching system for sample preparation was developed and compared with solid-phase extraction. Both methods show comparable limits of detection, but the column-switching technique has the advantage of fully automating the system.

Chromatography, High Pressure Liquid↗
PubMed1994

Efficacy of the peptidergic nootropic drug cerebrolysin in patients with senile dementia of the Alzheimer type (SDAT).

Cerebrolysin is a peptidergic nootropic drug with a multimodal mechanism of action. It is expected to have a positive influence on neurodegenerative diseases such as senile dementia of the Alzheimer type (SDAT). Experimental studies have shown Cerebrolysin to have a regulatory effect on energy metabolism, a positive influence on behavior through neuromodulation due to its peptide fraction, and most important, a neurotrophic stimulation. In SDAT and related disorders the neurotrophic effect of the drug could play a major role and influence the progress of the illness. A placebo-controlled double-blind trial was designed to examine the efficacy of the drug in SDAT. Confirmatory statistics were used for analysis. 120 subjects with mild to moderate dementia according to the Global Deterioration Scale (GDS) were included in the trial. Their performance on the Mini Mental State Examination (MMSE) was between 15 and 25. The diagnosis was substantiated by the Hachinski Ischemic Score and cranial computed tomography. The inclusion and exclusion criteria were formulated so as to prevent a distortion between the two arms by secondary dementia or other disease. The two arms received either placebo or the drug once a day (30 ml Cerebrolysin in 100 ml physiological saline i.v.) from Monday to Friday for four weeks. Physiological saline (130 ml) was used as placebo. Primary variables used for the statistical analysis were the Clinical Global Impression (CGI), which measures the improvement in symptoms, the SCAG score, and the performance in the trial-making test (ZVT-G). The self-assessment in the Bf-S and the activities of daily living in the NAI were used as secondary variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Postnatal administration of two peptide solutions affects passive avoidance behaviour of young rats.

The effects of two subcutaneously injected peptide solutions CERE (100 mg/kg b. wt.) and E021 (1 mg/kg b. wt.) and of 0.9% saline on passive avoidance reaction (PAR) of young rats were examined. Animals were trained and tested in a step-through avoidance task using a footshock of 0.5 mA or 1 mA. Step-through latencies were observed up to 200 s and from these data the percentage of good learners (latency = 200 s) and bad learners (latency < 200 s) was calculated. Two experimental schedules were performed (n > 6). In Expt. 1 rat pups were chronically treated with the substances within the first 7 days after birth. In Expt. 2 the 7 days of treatment started in the 4th postnatal week. In both experiments PAR acquisition was trained on the 28th day after birth (learning trial), PAR extinction testing started on the 29th day (retention trials). After applying a 0.5-mA footshock, rat pups treated with E021 within the first 7 days of life (Expt. 1) displayed significantly slower PAR extinction when compared to saline- and CERE-treated rats. In the 1 mA groups, significant differences in step-through latencies were measured between 0.9% saline- and E021-pretreated animals on retention day 11 and between saline and CERE on retention days 9 and 13. E021-treated rats of Expt. 2, receiving a footshock intensity of 0.5 mA, showed significant lower step-through latencies when compared to E021-treated rats of Expt. 1. In Expt. 2 no significant differences between treatment groups were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
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↗