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R Mayr

Publications and source records attributed to R Mayr.

At least 37 records · Page 2Linked to original sources
PubMed1991

The origin of the vestibulo-cochlear projection in the guinea pig.

Previous tracer studies have revealed the sacculus to be connected to the vestibular and cochlear nuclei in the guinea pig. Due to its own innervation pattern, an anterior and posterior part of the sacculus can be distinguished. The present study investigated whether the two parts differ concerning their fiber contribution to the vestibulo-cochlear projection. After tracing the nerve of the posterior sacculus with horseradish peroxidase (HRP), the vestibulo-cochlear fibers were clearly recognizeable and showed distinct terminal labeling within the cochlear nuclei. In contrast, no terminals were identified in the cochlear nuclei after tracing the anterior sacculus. These results may further substantiate the guinea pig vestibulo-cochlear projection as a central pathway for saccular acoustic sensation.

Afferent Pathways↗
PubMed1991

A bilateral maxillofacial trunk in man: an extraordinary anomaly of the carotid system of arteries.

In a Caucasian male, the maxillary artery (M) bilaterally arose with the facial artery anteromedially from the external carotid artery. On the right side, the M entered the infratemporal fossa between the neck of the mandible and the medial pterygoid muscle, whereas the left M pierced the medial pterygoid muscle, first being covered by the muscle and the angle of the mandible. On both sides, the M ran deep to the inferior head of the lateral pterygoid muscle and the buccal nerve. The right M lay deep to the inferior alveolar, but superficial to the lingual nerve, whereas the left inferior alveolar and lingual nerves had formed two roots, thus encircling the left M. The ascending palatine artery was replaced on both sides by palatine branches of the ascending pharyngeal artery. Since a bilaterial maxillofacial trunk with topographical relations as described herein has not been previously reported in man, the embryology and comparative anatomy of this variation are discussed.

Aged↗
PubMed1991

The human maxillary artery reinvestigated: I. Topographical relations in the infratemporal fossa.

The topographical relations of the human maxillary artery (IM) in the infratemporal fossa were studied in 102 individuals of both sexes. In the majority of the cases (55.4%), the artery was found in a lateral position to the lower head of the lateral pterygoid muscle (LPTER). In most of these specimens, the IM ran also lateral to the inferior alveolar, lingual and buccal nerves (type LA, 37.2%), whereas in 16.1% only the buccal nerve crossed the IM laterally (type LB). In 4.6%, the artery occupied a medial position to the LPTER. With respect to the branches of the mandibular nerve, an IM, passing deep to the LPTER, was lying either lateral to its main sensory branches (type MA, 1.9%) or coursing lateral to the inferior alveolar and lingual nerves, but medial to the buccal nerve (type MB, 23.8%). In 4.9%, the artery, running medial to the LPTER and the buccal nerve, was found to pierce the inferior alveolar nerve (type MC). In 7.4%, the IM was running medial to both the inferior alveolar and buccal nerves, but lateral to the lingual nerve (type MD), and in 3.9% the IM passed deep to all the branches of the mandibular nerve (type ME). Besides those common anatomical patterns, seven specimens showed different variations of the mandibular nerve. In about one third of the individuals, an asymmetric position of the IM to the LPTER (LM or ML) was present. None of the four cephalometric parameters and the two cephalic indices recorded in 55 individuals showed a significant correlation to the actual position of the IM (lateral or medial).

Female↗
PubMed1990

[Aneurysm of the ascending aorta].

Between January 1983 and March 1988 25 patients with aneurysms of the ascending aorta were operated, out of these only 15 (56%) electively. Acute incompetence (10) were the main indications for operation. Poststenotic aneurysms (2), mycotic (2) and saccular sclerotic (1) aneurysms have also been observed. A rare case of a ruptured ascending aorta due to histologically and serologically proven Brucellosis is presented. Valved conduits were used in 16 patients to reconstruct the aortic root, whereas the remaining patients had different types of supra-coronary reconstruction, i.e. resection with or without graft insertion (6 and 3 respectively). We lost 6 patients out of 25 during or immediately after operation. All of them were operated in an acute state of rupture or dissection with left heart failure, some of them already presenting neurologic deficits preoperatively. Operative and hospital mortality in 14 patients operated electively was 0%. Bentall's operation using valved conduits is a safe operation in elective patients with a reasonable mortality rate worldwide. Clinical follow up should include ultrasound studies of the operative site the remaining aorta, i.v. DSA and CT of NMR scanning in 6-12 month intervals in order to detect late complications as false or dissecting aneurysms.

Aged↗
PubMed1982

[Alcohol and we].

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Alcohol Drinking↗
PubMed1978

Course of denervation atrophy in type I and type II fibres of rat extensor digitorum longus muscle.

In the denervated extensor digitorum longus muscle of the rat type I and type II muscle fibres were differentiated histochemically and their course of atrophy was studied. Until 42 days after denervation type I and type II fibres could be identified by means of the myofibrillar ATPase reaction. Up to that time an exclusive atrophy of type II fibres was found. Type I fibres, the smallest of the normal muscle, did not change their diameters and therefore represented the largest fibres 42 days after denervation. Type II fibres of the "white" muscle portion, in which the larger IIB fibres are predominant, showed a higher rate of atrophy than those of the "red" muscle portion, in which the smaller IIA fibres are predominant: by 42 days the diameters of all type II fibres had gone down to equal values. Combined with a further progress of atrophy at later stages, there was a dedifferentiation of the histochemical properties, and the type I fibres exhibited atrophy as well. 120 days after denervation all muscle fibres were found to be highly atrophied.

Adenosine Triphosphatases↗
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

[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↗
PubMed1975

[Muscular neurotisation in traumatic abducens paresis (A new method of operative treatment) (author's transl)].

Traumatic abducens pareses occur quite often. The methods of operation known until now often achieved no good functional result. Therefore the authors experimentally tried to reinnervate by means of "musculr neurotisation" in 10 rabbits an extraocular muscle previously denervated. After 6 months the histological examination revealed the presence of newly germinated medullated nerve fibers and motor end plates. This was the proof that eye muscles may be reinnervated. Consequently in 5 patients with traumatic abducens paresis an implantation of the inferior oblique muscle was done. The functional improvement secured by this method of operation which for the first time has been applied on the human eye was good, in some cases even extremely good, depending on the time elapsed between lesion and operation.

Animals↗