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Biomedical subjects

G Wagner

Publications and source records attributed to G Wagner.

At least 721 records · Page 40Linked to original sources
PubMed1975

Electrical activity of grafted myometrium and its recording by radio-telemetry in unrestrained rabbits.

1. The electrical activity in myometrial grafts in fifty-one female rabbits with ear chambers fitted with pick-up electrodes has been monitored. An FM telemetry system has made long-term studies possible in the freely moving animal. 2. Two distinct patterns of electrical activity were observed either arising spontaneously or provoked by oxytocin. These were the 'long-duration burst' containing about 50-150 spikes, and the 'short-duration burst' containing 1-10 spikes. 3. The spike frequency within the long-duration bursts varied between 0-9 and 1-3 spikes sec-1 and was fairly constant during the first half of the burst. The frequency of the bursts in the long series of short-duration bursts was about 2-3 min-1. 4. When activity from grafts in two chambers in the same animal was monitored for long periods, spontaneous activity occurred at random throughout the day in each graft, indicating that the spontaneous activity was probably myogenic.

Animals↗
PubMed1975

New method for susceptibility testing with antifungal agents.

A new method for the determination of minimal inhibitory and fungicidal concentrations of antifungal agents for filamentous fungi is described. 5-Fluorocytosine (5-FC) was used as a representative agent and was tested against the following genera: Allescheria, Aspergillus, Cladosporium, Fonsecaea, and Phialophora. 5-FC was found to be inhibitory but not fungicidal for many of the fungi tested, including eight of clinical origin.

Antifungal Agents↗
PubMed1975

In vitro studies with combinations of 5-fluorocytosine and amphotericin B.

Synergistic antifungal activity of 5-fluorocytosine (5-FC) and amphotericin B was studied using an abbreviated checkerboard titration scheme. 5-FC was titrated in twofold increments (100 to 0.05 mug/ml) in the absence and presence of graded increments of amphotericin B (1.0. 0.5, 0.1, 0.05, and 0.01 mug/ml) in buffered yeast nitrogen base. A limited number of experiments were performed using expanded dual titration checkerboard schemes and growth curve studies. Forty-eight isolates of yeastlike organisms were tested; two were inhibited by the buffer system. Evidence of synergy, as indicated by a fourfold or greater reduction of the minimal inhibitory concentration of 5-FC in the presence of subinhibitory concentrations of amphotericin B, was seen with 11 of 46 isolates, or 24%, at the fungistatic level and with three isolates, or 7% at the fungicidal level. Indifferent results were obtained for 44 and 74% of the isolates, respectively, at the fungistatic and fungicidal levels. Antagonism was observed with three isolates.

Amphotericin B↗
PubMed1975

Auto-transplantation of rabbit myometrium into ear-chamber and recording of its activity.

A transparent ear-chamber and its installation in the rabbit is described as well as the subsequent autografting of myometrial tissue into the connective tissue formed in the chamber. Of the rabbits initially provided with ear-chambers 65% were found to be suitable for grafting while finally only 40% of these presented activity either spontaneously or induced by stretch or oxytocin. Qualitative evaluation of the mechanical activity was obtained by photo-electric recording of the transmission of light through the graft. An evaluation of the electrical activity was made possible by recording volume conducted potentials from wire electrodes in contact with the grafted tissue. A close time interrelationship between electrical potentials and change in transmission of light of the graft was found. Oxytocin produced electrical activity and blanching of the graft. It is concluded that recording of the electrical activity provides the most reliable way of expressing the activity of grafted myometrium.

Action Potentials↗
PubMed1975

Function of myometrial graft at time of parturition in the rabbit.

Thirteen rabbits equipped with ear chambers containing myometrial grafts were studied during late pregnancy, spontaneous and induced parturition and early puerperium. Spontaneous electrical activity of the graft was recorded by means of F.-M. telemetry transmission in the unrestrained animals. Furthermore the reaction to intravenously injected oxytocin (threshold determination) was recorded daily. During the last 5 days before spontaneous delivery increasing spontaneous activity of the tissue was observed. During the same period the response to oxytocin increased. Concomitantly with the delivery of the litter a period of rhythmic activity was observed. This period had a sudden onset and lasted 12-55 min, while the delivery itself only lasted 6-16 min. Similar activity patterns could be evoked in the early post-partum period by 100 mU oxytocin given iv. In 3 rabbits, doses from 80-300 mU oxytocin induced complete delivery. During the 48 hours' period after delivery spontaneous activity (single spikes and series of bursts) was observed. The response to oxytocin was further increased. It is concluded that as the graft is not influenced by nervous regulation, mechanical influence or local humoral factors the spontaneous parturition and the change in excitability must therefore be due to one (or more) systemic, humoral factor(s).

Action Potentials↗
PubMed1975

[Morphologic studies on the effect of acrylnitrile in subchronic intoxication experiments in the white rat].

100 female and male white rats were treated with acrylnitrile using 4 various dosages. It was our practice to give orally acrylnitrile in physiological sodium chloride solution by probang, and the treatment was continued for 69 days from Monday to Friday in the week. After the treatment with acrylnitrile from the 70th day the animals were killed in intervals. Blood of orbital venous plexus was analysed by electrophoresis for determination of serum proteins, and organs were investigated histologically. It has been shown that of all organs the greatest alterations have been found in livers, kidneys and lungs. Taking by surprise our studies indicated that the application of 1/16 LD50 acrylnitrile dosage cause greater morphological damages in liver than those applications of higher concentrations in other groups.

Acrylates↗
PubMed1975

[Flight leadership in flocks of homing pigeons].

Groups of 3-5 homing pigeons individually recognizable by different colours of their plumage were followed by helicopter on their way home. In most cases the animals flew together as a group with frequently changing leadership. Flight formations in terms of leadership were noted every minute. It was examined statistically whether the flight order varies at random or whether there are leading and led birds. In 6 out of 7 experiments with groups of 4-5 pigeons flight order was far from random, one or two pigeons proving to be leaders. In only one experiment leadership did not differ from a random distribution. No correlation could be found between the tendency to lead within a group and homing performance of the single pigeon when released individually.

Animals↗