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Biomedical subjects

V Herrmann

Publications and source records attributed to V Herrmann.

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

Evidence that a 16-kilodalton integral membrane protein antigen from Schistosoma japonicum adult worms is a type A2 phospholipase.

Type A2 phospholipase (PLA2) activity has been observed in integral membrane protein extracts of Schistosoma japonicum. Antiserum raised against bee venom PLA2 recognized a single 16-kDa band in the parasite extracts; it also localized to antigen in the gut lining of fixed adult schistosomes as shown by immunofluorescence techniques. Evidence was obtained that the molecule was expressed at low levels in comparison with other integral membrane proteins and was weakly immunogenic in rabbits. Two oligonucleotide probes were constructed on the basis of highly conserved regions between the nucleotide sequences of rat, bovine, rattlesnake, and bee venom PLA2; these probes were used to isolate S. japonicum genomic DNA phage clones. A 1.8-kb FnuD2 fragment was shown by Southern blot analysis to strongly hybridize with the 5' 32P-labeled PLA2 oligonucleotides in both S. japonicum genomic DNA and DNA from one of the phage clones. The nucleotide and predicted amino acid sequences of this fragment revealed homology with the C terminus of PLA2s from different species.

Amino Acid Sequence↗
PubMed1990

[Neuromuscular diseases and respiratory insufficiency in newborn infants].

Myopathological examinations which served to gain information on the potential impact of neuromuscular disease on the syndrome of perinatal respiratory failure included 47 consecutively deceased premature infants and neonates. A definite muscular disease could not be safety diagnosed in any case. However, only a very small number of investigations and data on the initial (possibly prenatal) manifestations have been available up to now. We found a total of 11 cases with increased intrafibrillary fat deposits coupled with mitochondrial aggregations in three cases. In seven cases, we found a retarded maturation ranging from three to nine weeks. Focally manifest myopathic changes were recorded in three cases. In one case, a large-group atrophy was found which might indicate the existence of a defect in the region of the second motor neuron. Biochemical backup investigations are necessary to be able to assess the relatively high incidence of increased fat deposits. We consider myopathological examinations of premature infants who died of respiratory failure to be desirable because far more comprehensive studies are necessary to be able to assess the importance of perinatally occurring muscular changes for the diagnosis of neuromuscular diseases.

Humans↗
PubMed1990

Outpatient dobutamine for end-stage congestive heart failure.

Eleven patients with refractory class IV congestive heart failure who were not candidates for cardiac transplantation were given iv dobutamine therapy on an outpatient basis. All patients underwent hemodynamic evaluation to confirm a beneficial response to low dose (5 micrograms/kg.min) dobutamine and to establish arrhythmia control both on and off dobutamine before hospital discharge. Six of the 11 patients could not be weaned from dobutamine in hospital and were discharged on continuous infusion (maximum dose, 5 micrograms/kg.min), while four were discharged with an infusion regimen ranging from 3 to 5 consecutive days/wk. All patients had a chronic venous access placed and were instructed on the use of an external battery-powered infusion pump with a container holding a concentrated solution of dobutamine hydrochloride. All infusions were delivered at home on an ambulatory basis. Intravenous drug support was discontinued gradually over an average of 3.2 months; seven of 11 patients were able to be weaned entirely from iv inotropic therapy and were maintained on oral therapy alone. Seven of the 11 patients (six of whom were maintained on oral therapy alone) required no hospital readmission during the infusion or follow-up period.

Adult↗
PubMed1988

[The healing of osteotomies of the lower jaw and the adaptation of the masticatory muscles after miniplate osteosynthesis in rabbits. I. Radiologic and histological evaluation of the lower jaw].

Radiographic and histological investigations were carried out on a total of 15 rabbits after lower-jaw osteotomy and miniplate osteosynthesis. After the removal of the lower jaw (4, 8, 12 and 24 weeks) consolidation of the osteotomy surfaces without complications was observed in all animals. Radiographic examinations showed that callus formation in the operated area increased as the experiment proceeded. Histological observations made clear that only secondary bone-fracture healing resulted which must be attributed to the operation technique. These findings show that the lower jaw of the rabbit is very well suited to experimental research on miniplate osteosynthesis.

Animals↗
PubMed1988

[Osteotomy healing of the lower jaw and the adaptation of the masticatory muscles after miniplate osteosynthesis in rabbits. II. Response pattern of the masticatory muscles (M. masseter)].

16 operated 4 control animals of both sexes were included in the study following osteotomy of the lower jaw and subsequent miniplate osteosynthesis. In addition, muscle tissue excised from 8 rabbits was evaluated at the time of the operation as additional normal material. The study was conducted over 4, 8, 12 and 24 weeks, after which periods the animals were killed and their left and right masseters examined and compared in histological, histochemical and morphometric terms. The masticatory muscles of the control rabbits displayed a marked sex dimorphism. The males had strikingly large, predominantly type-2 fibres, whereas the fibre diameters in the females were found to differ less clearly, with type-1 fibres being predominant. In terms of muscle regeneration, it was found that following soft-part trauma small localized defects (biopsy) had healed completely after 12 weeks. In the residual parenchyma, signs of adaptation to a changed mastication as a result of the experimental operation (osteotomy of the lower jaw, miniplate osteosynthesis, muscle biopsy) could be identified. Atrophy as a result of non-use was found to occur to a limited extent, whereas the number of type-2C fibres and fibre type transformations were raised significantly. After the surgery, the organization of the impaired muscle fibres was aided by a stabilization and rest positioning of the parts concerned. The muscle fibres reinnervation that followed was supported by functional exercise and nerve impulses.

Animals↗
PubMed1987

[Histogenesis, degeneration, regeneration and adaptation, aging and compensation in the skeletal muscles].

The concept of multicellular histogenesis of skeletal muscle fibre is the basis for understanding embryonal genesis of the voluntary muscles as well as muscle fibre regeneration. Formation and maintenance of the neuromuscular units are preconditions for function. Embryonic development and histogenesis regeneration are described. Changes resulting from metabolic defects, trauma, neurogenic and muscular disease are contrasted. Changes in nerves and synaptic junctions due to degeneration and regeneration are illustrated. Alteration in fibre type composition and muscle fibre diameter are regarded as the principle form of muscle adaptation to a changed loads. A central nervous system mechanism influencing fibre type and a peripheral humoral mechanism influencing the magnitude of peripheral motor units are postulated. The role of intramuscular sprouting is underlined. The structurally recognizable correlates of aging, such as decreased fibre diameter, increasing fibre type grouping and reduction of the total number of muscles fibres should be viewed as physiological phenomena. Sensomotor regulation of compensatory mechanism of muscular activity including fibre type grouping, compensatory hypertrophy, target fibres and ring fibres results in distinctive patterns under etiologically distinct pathological conditions.

Aging↗
PubMed1987

[Long-term experimental electric stimulation of denervated laryngeal muscles in dogs. Myopathologic findings].

The recurrent laryngeal nerve was transsected unilaterally and a device for electrical stimulation of the denervated muscles was implanted in 6 dogs. After 3 to 11 months the laryngeal muscles were obtained and histopathologically demonstrated a striking neurogenic pattern. In place of homogeneous muscle fiber atrophy, a patchwork of grouped fibre atrophy, compensational hypertrophy, fibre regeneration and reinnervation as well as muscle fibre type grouping were observed. Muscle fibre type distribution in the m. cricoarytenoideus posterior, m. vocalis and m. cricothyroideus was determined and compared between the normal and denervated sites. All muscles showed some changes in the fibre type distribution, including type grouping, but these were most pronounced in m. vocalis. The average fibre diameter decreased whereas fibre size variability increased. Mixed muscle fibre atrophy with compensatory hypertrophy of a single fibre type predominated. There was no evidence of disuse atrophy. The electrically stimulated muscles could be maintained at a reduced functional level throughout the study period.

Animals↗
PubMed1986

[Formation and repression of neuromuscular endplates in neurogenic and muscular lesions].

The motor endplates and intramuscular nerves of rat and rabbit masticatory muscle were preferentially demonstrated using an acetylcholinesterase reaction followed by silver staining. The regeneration of the neuromuscular unit was followed serially at the site of an earlier biopsy. Using observations concerning the sproutings of neuronal fibers in normal and operated animals, a hypothetical generalization of the phenomenon is proposed and evaluated in the light of the literature. Intramuscular sprouts of motor axons are detectable both in normal and partially denervated muscle. These can be regarded as the precondition of the muscle's ability to adapt to an altered stress situation. Single muscle fibers and synapses are multiply innervated by different alpha-motor neurons with subsequent fiber transformation via an intermediary stage, the 2C fiber. Following neurogenic damage a trigger is released from the denervated muscle tissue and damaged nerve parenchyma which stimulates the reinnervation of surviving motor endplates by axon sprouting and new synapse formation. Collateral, nerve stem, and terminal sprouts may occur singly or multiply. As long as denervated muscle fibers are present triggers for synapse formation and axon sprouting, as opposed to repression, continue to be released, resulting in a period of poly-innervation. The degree of sprouting correlates with the extent of nerve damage. The period of innervation is not affected by muscle damage alone. Complete or partial fiber regeneration products will survive only if they reach an innervation zone where neurotransmission is insured by the presence of sprouts and synapses. The period of poly-innervation is followed by a period of synapse repression whereby the redundant sprouts and synapses are reabsorbed. The length of the axon determines the sprouts resistance to reabsorption. The connections which survive are those which are the shortest between the endplate and the stem nerve. Intramuscular sprouting can be experimentally stimulated by, among other factors, partial denervation, oxygen deficiency, toxic inactivation, an altered stress situation and exogenous gangliosides.

Animals↗
PubMed1985

[Animal experiment and biopsy studies on the cause, manifestations and diagnostic relevance of perifascicular muscle fiber atrophy].

On the basis of previous (n = 23) and current muscle biopsies (n = 25) as well as five animal-experimental investigations, the paper deals with the cause and the manifestation of perifascicular muscle-fiber atrophy. A deteriorated trophic situation of the subfascial or marginal muscle fibers in patients suffering from immunocomplex vasculopathies in connection with a reduced supply of blood to the muscles is seen as the cause of the areactive weight loss (atrophy). This is accompanied by a considerably reduced capillary supply of blood to the muscle fibers. Even in normal conditions, the portion of collateral vessels and capillaries is lower in the subfascial region than in the center of the fascicle. When the blood supply is disturbed, the marginal fibers are in a trophic situation worse than that of the central muscle fibers. They become atrophied. In responsive patients, the muscle fibers regenerate and recapillarize during the convalescence period. This can be shown histochemically by means of the alkaline phosphatase reaction. The extent of perifascicular musclefiber atrophy can be fixed in quantitative terms by the method of Baumli and Mumenthaler. Where a second biopsy is indicated, results can be obtained regarding the changes in the perifascicular atrophy as a consequence of the therapy provided.

Acid Phosphatase↗
PubMed1983

[Effect of peripheral nerve lesions on histochemical enzyme reaction patterns in skeletal muscle fibers].

Peripheral neuropathies are a heterogeneous group of disorders. Myopathological changes exist in motoric and senso-motoric neuropathies. Histochemical and morphometric investigations of muscle biopsies indicate characteristic features: The most common changes in denervation are atrophic fibres and fibre groups. Patients with simple peripheral neuropathy show a more diffuse atrophy of muscle fibres with characteristical signs of denervation such as small angular fibres. Reinnervation takes place in the chronic neuropathies. Type grouping is a feature of reinnervation. The pictures of chronic neuropathies show fibre atrophy, small angular fibres, type grouping, and sometimes target fibres or whorled fibres. The muscle fibre histograms are of myopathic or of neurogenic type.

Biopsy↗
PubMed1983

[Problem of diagnostic muscle tissue removal: biopsy, preparation and preservation].

Intensive professional cooperation of all diagnostical branches needed incl. surgery is presupposition for the investigation of muscle biopsies. Knowledge needed on diagnostic clearing in advance and correct determination of kinds of biopsy as well as careful detraumatic taking of tela have decisive influence on the statement value of the result of investigation techniques concerning fine-tela. Muscle biopsies should be made exclusively at such places where the technical basis is available for optimum investigation and preparation.

Biopsy↗
PubMed1983

[Morphometric and histochemical studies of the masticatory muscles in growing white rats following ligation of the right common carotid artery].

White Wistar rats served for examinations to the masticatory muscles after ligature of the a. carotis communis dextra on the 42nd d after birth. Gravimetric determinations of the dry substance of the muscles were performed in a total of 229 animals. In 65 animals casts of the vessels in synthetic resin (Kallocryl M) were made and the inside diameters of the blood vessels of the corresponding vascular regions measured. Histological, histochemical and muscle-fibre-morphometric observations of the masticatory muscles were made in 10 animals. Due to processes of adaption the a. carotis communis sinistra with an enlarged cross-section supplied the head with an increased blood volume. However, the anatomical and physiologic conditions of the collateral blood vessels conveying blood to the right side of the head prevented the entry of same share of blood into that side. Obviously there is a causal connection between this circumstance and the reduction in the dry substance of the right-side masticatory muscles. Histologic investigations revealed an increase in the capillaries by 10 percent in the animals operated on. The reduction in the diameters of the muscle fibres on the right side of the head was accompanied by a change in the normal combination of fibre types. 2 out of 5 animals which had been operated on showed a fairly homogeneous distribution of the fibre types in the masticatory muscles. Fibres of type 2 tended to be more vulnerable than fibres of type 1. Pathogenetically, the reduction in the dry substance of muscles and the reduction in the diameters of the muscle fibres are caused by nutritive disturbances in connection with restricted circulation. The neuronal-trophic sphere and the mechanism which is responsible for the differentiation of the muscle-fibre types seem to be affected as well. The myokinetic synapses are not affected.

Aging↗
PubMed1983

Pacing dependent properties of the transmembrane potential in plateau-fibres of the mammalian atrial myocardium.

The effects of cycle length (CL) alteration on action potentials of isolated trabeculae of the common right atrial working myocardium (M) and isolated preparation of the crista terminalis (CT) of the rabbit heart were studied. Prolonging the CL increased the steady state duration of action potentials in M but decreased it in CT fibres. The repolarization of the post-pause action potentials of the M preparations was characterized by (i) a rapid initial repolarization followed by (ii) a plateau phase and (iii) a retarded terminal repolarization. In CT fibres the retarded repolarization was not observed and the duration of the post-pause action potentials at 90% repolarization is decreased. Premature action potentials of the M preparations were shortened at 90%, but were prolonged at 25% repolarization. Premature action potentials of the CT fibres were prolonged. The post-drive resting transmembrane potential of the M preparations moved to more negative values depending on the CL stimulation. The shift of the post-drive transmembrane resting potential to negative values in CT preparations was preceded by an initial depolarization. The initial depolarization was absent in M preparations. Myofibril-poor pale cells were found consistently in CT, but never in M preparations.

Action Potentials↗