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Biomedical subjects

H Gruber

Publications and source records attributed to H Gruber.

At least 145 records · Page 8Linked to original sources
PubMed1978

Motor innervation of striated oesophageal muscle. Part 2. Characteristics of the oesophagomotor fibres in the rat studied by implanting the vagus nerve into a skeletal muscle.

In 12 rats the right vagus nerve distal to its recurrent laryngeal branch was implanted into the inferior segment of the denervated sternohyoid muscle. One month after implantation the first signs of neuromuscular transmission at the vagal motor endings could be recorded. Two months after implantation the reinnervated muscles showed vigorous contractions on electrical stimulation of the vagus nerve. During the performance of propulsive waves of the oesophagus the implanted vagus nerve caused clonic to tetanic contractions of the sternohyoid muscle, thus proving the oesophagomotor genesis of the reinnervating nerve fibres. In addition, the vagus-innervated motor end-plates were shown to exhibit the same ultrastructural peculiarities as the original neuromuscular junctions of the oesophagus. In sections stained for cholinesterase it could be demonstrated that the oesophagomotor fibres had preferentially reinnervated the denervated motor end-plates. In many instances the subneural apparatus was not completely covered by the vagal axon terminals. Newly formed, ectopic vagal motor endings were few in number and confined to muscle fibres immediately adjacent to the site of nerve-implantation. Six months after implantation some of the vagal motor endings showed signs of degeneration. As in the oesophagus, the reinnervating oesophagomotor fibres proved to be unmyelinated, sometimes forming a plexus-like intramuscular network before terminating at motor end-plates. Myelinated vagal nerve fibres were also observed running between the skeletal muscle fibres, but they did not establish any demonstrable form of neuromuscular contacts. It was concluded that, in the rat, the myelinated fibres of the oesophageal nerves are afferent, whereas the oesophagomotor fibres, although supplying striated muscle, are unmyelinated.

Animals↗
PubMed1978

Motor innervation of the striated oesophagus muscle. Part 1. Intramural distribution of the right and left vagus nerve in the rat oesophagus as revealed by the glycogen depletion technique.

The muscularis propria of the rat oesophagus is entirely made up of striated muscle fibres. All fibres are of the same histochemical type, which is characterized by high activity of actomyosin ATPase, medium activity of oxidative enzymes and relatively strong reaction for phosphorylase. Prolonged stimulation (10 Hz, 30 min) of the vagus nerves causes depletion of the glycogen content of the oesophageal muscle fibres. This stimulation effect can be visualized by means of the PAS technique as well as by the histochemical reaction for phosphorylase. In 8 animals the right and in 8 animals the left vagus nerve were stimulated repetitively and the stimulated muscle fibres were identified in transverse sections of the oesophagi, stained for phosphorylase. The muscle fibres supplied by one vagus nerve are distributed all over the circumference of the oesophagus. In the upper third of the oesophagus stimulation of either vagus nerve depletes slightly less than 50% of the muscle fibres, whereas in the lower two-thirds the right vagus nerve seems to predominate to a certain degree. In 3 animals both vagus nerves were stimulated simultaneously. Bilateral stimulation produced a very extensive depletion. Only a few muscle fibres remained unaffected. Functional implications of the results, the question of polyneuronal innervation and the role of the myenteric plexus are discussed.

Animals↗
PubMed1978

[TV-pattern reversal stimulus (VECPs) in determination of refraction (author's transl)].

Pattern reversal VECPs show a dependence on visual acuity and therefore are suitable for objective determination of refraction, this method, however, was of limited clinical use for two reasons, as, on the one hand, the required impulse parameter was difficult to change using the traditional mechanically functioning pattern stimulator and, on the other hand, diagnosis war very timeconsuming. Using a pattern impulse picture presented on a monitor by an electornic impulse apparatus all impulse parameters can easily be changed and throught he introduction of a microprocessorsystem the evaluation can be observed on-line.

Evoked Potentials↗
PubMed1977

The accessory phrenic nerve in the rat.

Reinnervation studies of the diaphragm led us to reinvestigate the normal anatomy of the phrenic nerve of the rat. The phrenic nerve originates from the cervical nerve roots C4 and C5. In 16 out of 19 normal rats an accessory phrenic nerve was observed receiving its segmental fibres from C6. The number of myelinated axons of the accessory phrenic nerve varied from 41 to 101 (mean: 64.3, i.e. about 15% of the average number of axons in the common phrenic nerve). The accessory phrenic nerve innervates the dorsal part of the costal and the lateral part of the crural region, whereas the remaining parts of the hemidiaphragm are supplied by the segments C4 and C5. There is no evidence for any additional contribution to the motor innervation of the diaphragm from intercostal nerves.

Animals↗
PubMed1976

[Further experimental investigations on the therapy of gas gangrene with ozone and oxygen (author's transl)].

In continuation of a recently-published investigation on the effect of intramuscular injections of an ozone-oxygen mixture on experimental gas gangrene in the guinea pig, 2 additional experiments were performed in order to establish the efficacy of the therapy when given twice daily instead of only once. Futhermore, the effect of an analogous therapy was investigated with the use of pure oxygen. The ozone-oxygen therapy reduced the death rate from 100% in untreated control animals to 73.6 and 70.0%, respectively, in the 2 series of experiments. The median survival times were prolonged from 0.56 and 1.33 days to 5.50 and 6.66 days. The use of oxygen twice daily reduced the death rates significantly even further to 57.0 and 47.9%. With this therapy the median survival time was increased to 8 and more than 12 days. The differences in therapeutic effect of the 2 gases were not, however, statistically significant. On account of its simple applicability previous experiments on animals it is proposed that this therapy be employed also in cases of human gas gangrene. In addition, the bactericidal effect of CaCl2, as used in this experimental study, on vegetative forms of Clostridia is demonstrated.

Animals↗
PubMed1975

Internal structure of cat extraocular muscle.

Teasing preparations of cat extraocular muscles (EOM) were used to study the arrangement of muscle fibers and the distribution of the different cholinesterase-positive sites, i.e. (1) large motor endplates, (2) small motor endings of the 'en grappe' type, (3) myotendinous junctions and (4) myomyous junctions. The distribution of these cholinesterase-positive structures gives clear evidence of a complex muscle architecture of cat EOM. In the global layer of cat EOM, only multiply innervated muscle fibers run the whole length of the muscle. The focally innervated muscle fibers are generally shorter; they are usually arranged in series of two to three fibers being interconnected by myomyous junctions. Moreover, muscle fiber splitting is frequently present resulting in a netlike arrangement of muscle fibers. Most of the myomyous junctions occur between focally innervated muscle fibers, but also end-to-side connections of focally to multiply innervated muscle fibers are observed; multiply innervated muscle fi0ers have not been found connected to each other. In this layer, large motor endplates are distributed in several bands between origin and insertion. In the orbital layer all muscle fibers run from tendon to tendon, focally as well as multiply innervated ones. Here, large motor endplates are confined to a band in the middle of the muscle, and myomyous junctions are generally absent. Some functional implications of this complex architecture of cat EOM are discussed.

Animals↗
PubMed1975

Fournier's gangrene of the scrotum.

Gangrene involving the male genitalia is extremely rare. It may occur without any predisposing cause. This necrotic process passes through various stages, and is self-limited. No radical surgical procedure is indicated. A case of typical Fournier's gangrene of the scrotum is presented.

Acremonium↗
PubMed1975

[Experience with the written examination (multiple choice test) in the teaching of anatomy].

All students (400 each winter-term) receive extensive information at the beginning of the course "anatomical propedeutics": a timetable with recommendations for learning, a list of instructional objectives and of terminology and an instruction for that type of test, the students never had experienced before. Feed-back is given by computer-output containing comments on the objective related to a wrong answer and indicating sub-test scores. Correlation of scores with results in the following dissection course seems to be acceptable. Questions of the multiple-choice test were compared by pairs with questions asked for in confrontation with the anatomical object. A strong coherence was found in answering correctly the multiple choice questions and the related oral exam. Over-all experience with a multiple choice test administered in Austria for the first time was rather encouraging.

Anatomy↗