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Biomedical subjects

H Gruber

Publications and source records attributed to H Gruber.

At least 109 records · Page 6Linked to original sources
PubMed1984

[Familial binasal visual field contraction].

A 45-year-old heavy smoker was referred to the clinic for acute unilateral visual acuity reduction and irregular visual field constriction. An ischemic optic neuropathy with ipsilateral pit of the disc and medullated parapapillar nerve fibres was diagnosed. In spite of a normal fundus a visual field contraction in the upper nasal quadrant was found on the other eye. The son of the patient had bilateral crater-like holes of the disc with binasal visual field contraction. Similar visual field defects were found in the patient's daughter, with pseudopapilledema.

Female↗
PubMed1984

The chronically stimulated muscle as an energy source for artificial organs. Preliminary results of a basic study in sheep.

In 5 adult sheep the psoas muscle of one side was electrically stimulated through the muscle nerves with an implantable stimulation unit for more than 5 weeks. In the final experiments the isometric tetanic tension of the stimulated muscles was reduced to 50-70% of the contralateral normal muscle. The use of only 15 Hz as a stimulation frequency led to a transformation of the originally fast muscle into a slow muscle with more resistance to fatigue. Future application of the chronically stimulated psoas muscle for driving artificial organs is discussed.

Animals↗
PubMed1984

[Operative technic in muscle transplantation with microneurovascular anastomoses based on animal experiment studies].

The influence of the transient ischemia during free muscle transplantation with microneurovascular repair was studied in the rectus femoris muscle of the rabbit, as well as the effect of denervation and reinnervation by nerve suture. Both factors, ischemia and nerve suture, were taken together in a separate series. The functional results of the different kinds of reinnervation by nerve suture, by nerve implantation and by muscular neurotisation were compared. The possibility to use a motor nerve elongated to the contralateral side by nerve grafting was tested. In a further series the effect of changes of the initial tension of the muscle during the transplantation was clarified. These isolated factors were compared with the real transplantation from the left to the right side. As the most representative parameter for function the maximal tetanic tension was chosen for evaluation. Our results show that the following considerations in the operative technique are significant. To shorten the time of ischemia the donor and recipient area should be prepared for transplantation at the same time, the recipient vessels should be elongated before the muscle transplant is taken off, and the arterial anastomoses should be performed before the venous. For reinnervation of the muscle transplant nerve suture is more successful than nerve implantation. Both methods can be combined to make good use of all the potential of reinnervation. The muscular neurotisation should be used only in the face and for sphincter reconstruction. A contralateral source of reinnervation is useful in the face, but it is not in the extremities. The restitution of the original initial tension of the muscle after transplantation is of great importance.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

[Modified video-pupillography: indications and 1st experiences].

Besides of infrared-reflexphotometry several videosystems are used for pupillography. The main modification of our TV-pupillography consists of the connection of the infrared-camera with a videorecorder. Thus changes of the shape of the pupil can be evaluated continuously. Therefore, indications for our variant of pupillography are especially those types of anisocoria with loss of the round shape of the pupils.

Humans↗
PubMed1983

Is a crossover to the contralateral side by nerve transplants a satisfactory source for reinnervation of a muscle transplant? An experimental study in the rectus femoris muscle of the rabbit.

In ten rabbits the nerve branch to the left rectus femoris muscle was prolonged to the contralateral side by a nerve graft. Three months later the distal end of the transplant was connected to the transsected nerve branch to the right rectus femoris muscle. Nerve biopsies were taken from the muscle nerve, the nerve graft at the time of grafting and from the distal end of the nerve graft immediately before nerve suture in the second operation. Six months after the second operation the final assessment of muscle function and of the histology of the muscle and of the muscle nerve was performed. The functional results of the rectus femoris muscle reinnervated by a crossover nerve graft ranged between 6% and 56% of a normal standard muscle and seemed to be insufficient to justify a clinical use for muscle transplant reinnervation in the extremities. The histological findings also confirmed the basic possibility of elongating a motor nerve by nerve grafts, but the second nerve suture, the interposition of a long nerve graft, and the obviously changed reflex system probably caused a moderate and unpredictable muscle function.

Animals↗
PubMed1983

[Psychomotor disorders in psychiatric patients as a possible basis for new approaches in differential diagnosis and therapy. I. Results of initial studies in depressed and schizophrenic patients].

Tests that have rarely been used up to now in the psychomotor examination of psychiatric patients have been put together in accordance with our preliminary investigations to form a broader, standardized battery. With this new battery, which consists of the motorische Leistungsserie, a modified version of the Lincoln-Oseretzky motor development scale and the motor subtest of the Luria-Nebraska neuropsychological battery, a study has been carried out on 15 schizophrenics not actually treated with drugs, 15 endogenous and 15 non-endogenous depressed persons and 15 healthy controls. With the results of such a psychomotor "profile", measured over all items, psychotic patients can be clearly separated from the non-endogenous depressed patients and healthy controls. No significant differences have been found between non-endogenous depressed patients and healthy controls. These results are basically in agreement with many single findings in the literature. Results based on a broader battery for the investigation of psychomotor abilities in psychiatric patients could be of value in difficult differential-diagnostic problems and ought therefore to be studied further. In addition, the movement disturbances in psychotic patients, which have been measured by a broader standardized battery, could be the starting point in the development of specific psychomotor training programmes, which could improve the efficiency of conventional gymnastic and ergotherapeutic treatment methods. In this direction too, further studies would be useful and are indicated.

Adult↗
PubMed1983

The importance of the correct resting tension in muscle transplantation: experimental and clinical aspects.

The influence of a reduction of resting tension by elongation of the tendon on muscle function and morphology is investigated in the rectus femoris muscle of the rabbit. An elongation of the patellar tendon of 5 mm causes a reduction of the twitch tension to 73.5 percent of the contralateral control side and a reduction of the tetanic tension to 78.3 percent 6 months after surgery. The histologic, histochemical, and planimetric changes are similar to those reported by other authors for tenotomy, but they are less marked. The clinical relevance of these experimental results for free muscle transplantation with microneurovascular anastomoses and some technical details are discussed.

Animals↗
PubMed1983

Experimental free-muscle transplantation with microneurovascular anastomoses.

In 13 rabbits the rectus femoris muscle was freely transplanted from the left to the right side using microneurovascular anastomoses. About 7 months after surgery the muscle transplants were assessed functionally by force measurements. On the average, the transplanted muscles regained 55 percent of the maximal tetanic tension of unoperated, normal rectus femoris muscles, expressed as force per gram of muscle weight even 68 percent. After functional assessment, the muscles were weighed and then used for histologic, histochemical, planimetric, and biochemical evaluation. H&E-stained cross sections showed a high content of healthy muscle fibers; only some small atrophic and single fat cells were scattered over the cross sections. Good reinnervation over the sutured muscle nerve was confirmed by the type-grouping of muscle fibers in the NADH and myofibrillar ATPase staining. There was an excellent correlation between the functional results and the histologic picture as well as the content of choline acetyltransferase (CAT). A certain parallelism was found between the function of the transplants and the content of hexokinase, but none for the other estimated muscle enzymes, such as malate dehydrogenase (MDH), creatine kinase (CK), and lactic dehydrogenase (LDH). All enzyme levels were lower than in normal muscles. The results of this experimental series underline the utility of muscle transplantation with microneurovascular anastomoses to restore lost muscle function, even in the extremities, when strong forces are needed.

Animals↗
PubMed1982

Coupling factor.

Explore the source record for details and available documents.

Animals↗
PubMed1982

Acute reduction in osteoclast number during bone repletion.

Growing rats were fed a calcium-deficient diet for 12 days to induce bone loss and were subsequently placed on a calcium-replacement diet for 1 to 3 days to evoke bone repletion. Control animals were fed the calcium-replacement diet continuously. Twelve days of calcium deprivation resulted in a 21-fold increase in the number of endosteal osteoclasts in the tibial diaphysis as compared with controls. These osteoclasts, however, rapidly disappeared from the endosteum after restoration of dietary calcium. Only 14% of these endosteal osteoclasts remained after 1 day, and no osteoclasts were present after 3 days of calcium replenishment. During this time, plump osteoblasts replaced osteoclasts on the endosteal surface. The number of osteoclasts in the marrow space also changed strikingly. An 11-fold increase in the number of osteoclasts in the marrow space occurred during the calcium-deprivation phase. However, the greatest increase (39-fold) was observed during the first day of calcium replenishment. Thereafter, the number of osteoclasts in the marrow space declined and, after 3 days of calcium replenishment, returned to the control level. During calcium replenishment, acid phosphatase-positive fragments in the marrow space appeared concomitantly with osteoclast disintegration and fragmentation. The kinetic changes and acid phosphatase staining of these fragments suggest that the fragments are the products of disintegrating osteoclasts, a finding consistent with the hypothesis that the fate of some osteoclasts in vivo is cell death. At the end of calcium deprivation, serum iPTH levels and the production of 1,25-dihydroxyvitamin D3 from 25-hydroxyvitamin D3 were significantly increased compared to controls. After 3 days of calcium replenishment, serum iPTH had decreased to control levels, but the production of 1,25-dihydroxyvitamin D3 was still elevated. Changes in serum iPTH and the production of 1,25-dihydroxyvitamin D3 cannot, therefore, be totally responsible for the observed decrease in osteoclast number during bone repletion. Bone repair after calcium deprivation may be a locally controlled phenomenon.

Acid Phosphatase↗
PubMed1982

[Parafoveolar scotomas in microinfarcts of the optic pathways (author's transl)].

Small parafoveolar scotomas in microinfarction of the optic pathways are often not demonstrated, or only inaccurately so, in conventional kinetic perimetry. By using Amsler's grid it is possible to determine accurately the shape and position of such visual field defects. Some remarkable variants of these scotomas are described.

Adult↗
PubMed1982

[Modification of the swinging flashlight test].

As a simple screening method our modification of the Swinging Flashlight Test permits unilateral organic and functional visual disturbances to be differentiated in patients with clear media and normal fundi and, in addition, photographic documentation of the results. An additional advantage of the authors' method is the exclusion of possible artefacts inherited in the Swinging Flashlight Test.

Humans↗
PubMed1982

An experimental comparison of the different kinds of muscle reinnervation: nerve suture, nerve implantation, and muscular neurotization.

In this experimental study, the changes in histologic pattern and functional recovery of the rectus femoris muscle of the rabbit were investigated 6 months after denervation and immediate microsurgical repair of the nerve supply of the muscle. Three different ways of reinnervation were used: nerve suture, nerve implantation directly into the muscle, and muscular neurotization by the underlying muscle. For evaluation, histochemical methods and tension measurements were used. In the results, nerve suture and nerve implantation were superior to muscular neurotization. Nevertheless, muscular neurotization was successful in all cases and led to positive EMG recordings. The functional recovery in the nerve suture and in the nerve implantation groups was astonishingly high and reached 70 to 80 percent of the tension of the control muscles. The results of this experimental study and their clinical relevance are discussed.

Animals↗