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Biomedical subjects

H Gruber

Publications and source records attributed to H Gruber.

At least 91 records · Page 5Linked to original sources
PubMed1989

Effects of ascorbic acid in alkaptonuria: alterations in benzoquinone acetic acid and an ontogenic effect in infancy.

The effects of ascorbic acid on the excretion of homogentisic acid and its derivative benzoquinone acetic acid were studied in two adults and three infants. The administration of relatively large amounts of ascorbic acid to the adults was followed by a disappearance of benzoquinone acetic acid from the urine, whereas the level of excretion of homogentisic acid did not change. This could have relevance to the pathogenesis of ochronotic arthritis. In the 4-mo-old infant and the 5-mo-old infant ascorbic acid in the urine may have doubled the amount of homogentisic acid, presumably through an effect on the immature p-hydroxyphenylpyruvic acid oxidase. Dietary reduction of the intake of tyrosine and phenylalanine substantially reduced the excretion of homogentisic acid.

Aged↗
PubMed1989

[Anatomy of the atrophic mandible. 1. The location of the mandibular canal in the atrophic mandible].

43 atrophic left hemimandibles were divided by 6 saw cuts made between the mental foramen and the third molar to analyze the location of the mandibular canal. Mandibles were classified by the severity of alveolar absorption using Atwood's classification and changes in the distances of the mandibular canal from the superior and inferior borders of the mandibular body were correlated wit the degree of atrophy. Measurements were obtained with a digitizer and a computer and results were analyzed statistically. The following statistically significant observations were made: The distance of the mandibular canal to the external lingua and buccal cortical layers did not change with increasing atrophy, but remained remarkably constant. By contrast, highly significant changes in the distance of the mandibular body were found to be present. These were more pronounced at the superior than at the inferior border. The changes seen were consistently most severe at the level of the first molar. Prior to surgical interventions involving an atrophic mandible the location of the mandibular canal should invariably be identified by imaging techniques such as orthopantomography, telemetric X-rays, tomographies, CT and MRI, if indicated, in order to avoid injuries of the inferior alveloar nerve and preclude forensic consequences.

Aged↗
PubMed1989

Morphologic and functional aspects of pelvic floor muscles in patients with pelvic relaxation and genuine stress incontinence.

Thirty women (mean age 49 years; range 33-74) with mild to moderate pelvic relaxation and genuine stress incontinence underwent preoperative urodynamic studies. Biopsy specimens from the levator ani muscles during vaginal hysterectomy and repair were evaluated for the number and the individual diameters of type I (slow-twitch) and type II (fast twitch) fibers. Biopsies from 11 women revealed striated muscle tissue, whereas no muscle tissue was observed in the other 19. Compared with patients without muscle tissue, subjects with positive muscle findings showed significantly higher transmission ratios (55.0 +/- 23.4 versus 32.9 +/- 22.1%; P less than .05). Mean diameter and counts of types I and II muscle fibers decreased significantly with age (P less than .05). Urethral closure pressure during stress significantly increased with mean diameter of type II muscle fibers (P less than .05). In contrast to patients with severely damaged pelvic floor muscles, the presence of slow-twitch fibers is associated with improved support of the pelvic viscera, especially under conditions leading to intra-abdominal pressure rise. The presence of fast-twitch fibers improves the periurethral continence mechanism, resulting in an increase of urethral closure pressure during stress.

Biopsy↗
PubMed1989

[Blockade of the suprascapular nerve in shoulder pain].

The pathological course of the most common diseases of the shoulder includes pain as a main symptom. Besides other methods of treatment the infiltration of the suprascapular nerve can improve the therapeutic methods in many cases. The technique of Gordh, used as an adjuvant procedure, is shown. Since we used this technique of local anaesthesia, in 32 of 42 cases a temporary release from pain could be achieved. In 6 more patients it led to an significant reduction of pain. In conclusion this method of local anaesthesia can be recommended as an additional treatment of patients with pain of the shoulder because the rate of complications is low and the technique can easily be done.

Cervical Plexus↗
PubMed1988

Isomyosin changes after functional electrostimulation of denervated sheep muscle.

Isomyosin analyses by biochemical, immunochemical, and histochemical investigations have been carried out in five sheep following unilateral recurrent laryngeal nerve paralysis and direct functional electrostimulation of the denervated cricoarytenoid posterior muscle. Myosin light chains were identified by two-dimensional gel electrophoresis. Myosin heavy chains were analyzed by one-dimensional SDS-polyacrylamide gel electrophoresis. Slow myosin heavy chain was identified by orthogonal peptide mapping and immunochemistry. The stimulation effect at cellular level was determined using adenosine triphosphatase (ATPase) histochemistry. A dramatic increase of the type 1 fiber area (slow, fatigue-resistant fibers) could be seen after many weeks of an increasing regime of low-frequency direct electrical stimulation. Biochemically, the amount of slow myosin was always higher than in normal muscles. Some muscles were transformed almost completely to the slow type. At the time they were studied and with the methods employed, the expression of embryonic isomyosin was not observed. In conclusion, after numerous weeks of maintained functional activity, elicited by direct electrostimulation, the denervated muscle regionally showed areas of hypertrophy or at least lack of atrophy of slow myofibers without major signs of muscle damage.

Animals↗
PubMed1988

Histochemical characteristics of human mimic muscles.

Eight different mimic muscles of 13 human cadavers (7 male, 6 female) were studied by histochemical techniques. In sections stained for myosin ATPase the composition of fibre types was quantitatively evaluated by computer-assisted image analysis. The data were compared to those of 2 muscles in the lower limb of the same individuals. According to the percentage of the type I muscle fibres 3 groups of mimic muscles were distinguished: (1) the orbicularis oculi muscle (15%), (2) the major zygomatic, levator labii superioris, levator anguli oris, depressor anguli oris muscles and platysma (27-38%), and (3) the occipitofrontal and buccinator muscles (57-77%). For comparison, the gracilis and rectus femoris muscles were built up by 36% and 48% of type I fibres. The average diameters of fibres in mimic muscles were significantly less than in the 2 limb muscles. Differences in muscle fibre size between male and female specimens were not significant. The relevance of morphological characteristics of mimic muscles for facial expression and reconstructive surgery is discussed.

Adenosine Triphosphatases↗
PubMed1988

Effect of DNA sequence and structure on nuclease activity of the DexA protein of bacteriophage T4.

The bacteriophage T4 dexA gene product is required during infection of Escherichia coli strains carrying a mutation in the optA gene. We purified the DexA protein from cells which overproduced the protein. The protein was assayed for nuclease activity on synthetic di- and oligonucleotide substrates of known sequence and secondary structure. Sequence and structure significantly affected nuclease activity. The properties of the enzyme may explain the requirement for the DexA protein during infection of optA mutant hosts.

Base Sequence↗
PubMed1988

[Vascularized nerve transplant--theoretical advantages and disadvantages].

A survey of publications dealing with vascularized nerve grafts is given. The advantages and disadvantages are discussed by analyzing the published data. Until now the superiority of vascularized nerve grafts has not been proven by the published experimental and clinical results. This fact was underlined by the results of our own experimental investigations: In conventional nerve grafts performed on sheep it was shown that the functional results of reinnervation cannot be correlated to the degree of vascularization of the nerve graft or to number and morphology of the regenerated axons. Therefore, the indications for the clinical application of the vascularized nerve graft must be limited to the following conditions: Poorly vascularized recipient bed, thick nerve graft, unsuccessful previous conventional nerve grafting, and the necessity of vascular reconstruction at the same time.

Animals↗
PubMed1987

Surgical anatomy of the mimic muscle system and the facial nerve: importance for reconstructive and aesthetic surgery.

Mimic muscles are arranged in four layers regarding their origins, and these four layers should be considered when muscle tissue is added or lifted. All mimic muscles are built up by parallel fibers. Mean values of length, width, and thickness of the three lip elevators have been determined. These data might be of importance when dealing with this muscle system, which appears rather different from all other muscles in the human. The individual muscles receive their innervating facial nerve branches from their deeper surface when they belong to the superficial (first, second, or third) layer and from outside when they lie in the deepest (fourth) layer. Nerve branches communicate at least four times before innervating their respective muscles.

Aged↗
PubMed1986

[Visual field fluctuations in necrotic hypophyseal adenoma].

The authors report on an acute bitemporal visual field depression with spontaneous reversibility of the defects, associated with necrotic pituitary adenoma. As the same time as the visual field defects regressed it was established by computer tomography that the suprasellar portion of the pituitary tumor had diminished in size.

Adenoma↗
PubMed1986

[Functional electrostimulation of the denervated posticus muscle in an animal experiment: histo- and biochemical results].

Histochemical and biochemical investigations have been carried out in 2 sheep following unilateral recurrent laryngeal nerve paralysis and direct electrical stimulation of the denervated posticus muscles. The stimulation effect was determined histochemically (standard ATP-ase staining) and compared with the fibre pattern of normal posticus muscles. In addition, one-dimensional gel electrophoresis of myosin heavy-chain isoforms was carried out and correlated with the histochemical results. A dramatic increase of type I fibres could be seen after long-term low-frequency direct electrical stimulation of denervated posticus muscles of the sheep. Biochemically the amount of slow myosin heavy-chain isoforms was higher than in normal muscles.

Animals↗
PubMed1985

[Computerized perimetry in neuro-ophthalmologic diagnosis].

Computerized static perimetry is helpful in the diagnosis of lesions of the extrabulbar afferent visual system. Especially in cases with optic neuropathies static perimetry provides some advantages over kinetic methods: Early recognition of relative defects, especially of scotomas of low density. The results of the examination are independent of the examiner, which is very important for following up the course of diseases and the evaluation of therapeutic concepts. In some cases facilitation of classification regarding pathogenesis. Disadvantages of computer-controlled automatic perimetry are: Long duration of examinations, which cannot be tolerated by all patients with neurological diseases. False positive (pathological) findings as a consequence of tiredness of the patient or inadequate conditions of investigation.

Diagnosis, Computer-Assisted↗
PubMed1985

Time course of alterations in muscle transfers with microneurovascular anastomoses. An experimental study in the rectus femoris muscle of the rabbit.

The time course of alterations in muscle transfers with microneurovascular anastomoses was studied in 17 rabbits. The left rectus femoris muscle was transferred to the right side. For comparison, in some animals the right rectus femoris muscle was transferred from the right to the left side, but without vascular repair. Two, seven, 14, 21, and 30 days after transfer, the electric excitability, macroscopic appearance, histology, histochemistry, ultrastructure, and activity of muscle enzymes were assessed. In the transfers with microneurovascular anastomoses, almost all muscle fibers survived. Alterations were limited to those typical of a denervation-reinnervation process. Contrary to this, only a few atrophic fibers survived in the periphery of the transfers without vascular repair. By far, the greater central part underwent necrosis. A considerable amount of connective tissue developed. These results clearly show the functional superiority of microsurgically vascularized muscle transfers over those without vascular anastomoses. Excellent functional recovery is possible because the process of complete degeneration and consecutive regeneration, with inevitable augmentation of connective tissue, is prevented by the performance of vascular anastomoses.

Anastomosis, Surgical↗
PubMed1985

[Treatment and course of post-traumatic optic neuropathies].

Early commencement of therapy with corticosteroids in patients with optic nerve lesions after blunt head injuries is an alternative to transethmoidal decompression. Static computerized perimetry is eminently suitable for monitoring the course.

Follow-Up Studies↗
PubMed1984

Decrease of visual acuity in patients with clear media and normal fundi. Objective screening methods for differentiation and documentation.

For differentiation of unilateral reduction of visual acuity in patients with clear media and normal fundi, the Swinging Flashlight Test was used. Optic neuropathies as a rule give pathological results. On the other hand refraction scotomas, functional amblyopias and malingering produce a normal outcome of this test in general. For documentation of afferent pupillary defects a photographic method is described. Electronystagmography is advocated as a method for detection of malingerers and neurotics among patients complaining of acute uni- or bilateral visual acuity reduction. Optokinetic nystagmus is recorded using Bangerter's filters in front of the patient's eye. This method allows a certain estimation of the visual acuity.

Electronystagmography↗