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Biomedical subjects

A Wagner

Publications and source records attributed to A Wagner.

At least 433 records · Page 24Linked to original sources
PubMed1983

[Effect of Faustan (diazepam) on the normal and myotonically reacting frog skeletal muscle].

The antimyotonic effect of Faustan (diazepam) was investigated in the experimentally induced myotonia by 2,4-dichlorophenoxyacetate (2,4-D). The results show that Faustan does not improve the myotonic phenomena. Neither was the fall in membrane potential prevented nor were the myotonic muscle fiber changes of 2,4-D and had in its turn a depressive influence on the muscle. Depending on the concentration the drug developed a more depressive effect on the mechanical reaction than the electrical activity. These findings are compared with the results described in the relevant literature and are discussed in connection with the inhibition of electro-mechanical coupling.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1983

The different types of synapses in the thalamic nucleus ventralis anterior (VA) of Saimiri sciureus and their degeneration after pallidum coagulation.

In the squirrel monkey (Saimiri sciureus) the nucleus VA or lateropolaris (L. po), occupying the rostro-lateral pole of the thalamus, contains 7 principal types of synapses, two of which have axo-spinous variants, i.e., type I LR (spi) and type V SO (spi). The synapses of type I LR (Large boutons, Round to ovoid vesicles) and type II EF (Encapsulated bouton, elongated to Flat vesicles) contain large vesicles sometimes attached by neurofilaments. Because the type IV MR (Medium size, Round vesicles) synapses have virtually the same kind of axo-dendritic synaptic contacts as type I, either with or without aggregations of presynaptic vesicles, they belong to the same category of afferent boutons, differing only in size and in the number of mitochondria. The small axo-dendritic type III SR synapses (Small boutons, Round vesicles) are densely packed with vesicles having a relatively dense center, and undergo markedly asymmetric contacts with dendrites. The type V SO (Small bouton, Ovoid vesicles) synapses, the most frequent type of synapses, have larger pale ovoid vesicles in a bell-shaped bouton that is in asymmetric contact with a small dendrite. The subtype V St, which likewise contains pale ovoid vesicles has a stiletto-shaped rather than bell-shaped bouton which undergoes an asymmetric contact. In parallel to the other ventro-oral (or VL) nuclei, the nucleus VA possesses two types of presynaptic dendrites: type VI DE (Dendritic terminal with sparse, Evenly distributed vesicles) suspended among the neurofilaments; and type VII DC (Dendritic terminal in which many ovoid vesicles are Clustered). In the type VI junctions, the synaptic membrane specializations are difficult to detect. After circumscribed pallidum externum lesions in the squirrel monkey, many type I LR and type IV MR synapses, and a lesser number of type II EF synapses, undergo dark degeneration. In contrast, after such lesions the type VI DE and type VII DC dendritic terminals never show signs of degeneration. Also the bell-shaped type V SO terminal occasionally undergoes degeneration with darkening of the axoplasm; the subtype V St terminal, however, does not. Thus, it may be assumed that the type I LR, type IV MR, type II EF and type V SO boutons represent terminals of direct neuronal connections between the pallidum and thalamic nucleus VA.

Afferent Pathways↗
PubMed1982

Depolarizing IPSPs and Depolarization by GABA of rat neostriatum cells in vitro.

In neostriatal slices pretreated with sodium pentobarbital (100 microM) and 4-aminopyridine (50 microM), intrastriatal stimulation elicited EPSPs followed by a slowly decaying depolarization which lasted about 200 ms and was associated with a membrane conductance increase and a suppression of spike potentials. This depolarizing inhibitory synaptic action could be blocked by picrotoxin (50 microM) or bicuculline (50 microM). The reversal potential for the slowly decaying depolarization was -57 to -62 mV, i.e. it was positive with respect to the resting membrane potential (mean = -67 mV). GABA, injected into the tissue in the vicinity of the recording electrode by pressure application, or added to the perfusate (10 microM -1 mM), depolarized the cells and reduced both the membrane resistance and the amplitude of EPSPs. The reversal potential of GABA depolarization was found in a potential range approximating that of the slowing decaying depolarization. These results are compatible with the assumption that GABA is the transmitter of an intrinsic inhibition in rat neostriatum, but indicate that GABA-mediated IPSPs of neostriatal cells in vitro are depolarizing at the resting membrane potential. The possible reasons for this are discussed.

Animals↗
PubMed1982

The distribution of crossed and uncrossed optic fibers in the different layers of the lateral geniculate nucleus in the tree shrew (Tupaia glis).

The laminar distribution of crossed and uncrossed optic fibers was studied in the lateral geniculate nucleus (LGN) in the tree shrew (Tupaia glis) following unilateral enucleation. For the investigation of the termination of optic fibers the transneuronal degeneration method and experimental EM were employed. By using formvar film-coated slot grids, all six layers of the LGN could be studied in a single ultrathin section. Degeneration of crossed optic fibers was observed in layers 1, 3, 4 and 5 of the contralateral LGN. The uncrossed retinofugal fibers supply layers 2 and 6 of the LGN. The degeneration in layer 4 was less pronounced than that in the other layers. Ipsilateral and contralateral optic fibers were well separated. Filamentous as well as dark types of degeneration were found in the LGN after enucleation. The optic terminals (RL boutons) were seen only in the synaptic glomeruli.

Animals↗
PubMed1982

Effects of lysine-vasopressin and 1-deamino-8-D-arginine-vasopressin on memory in healthy individuals and diabetes insipidus patients.

Central diabetes insipidus (DI) patients showed impairments in short- and long-term memory functions, but not in attention and concentration, as compared to healthy individuals. A single i.m. injection or sub-chronic intranasal administration of either lysine-vasopressin (LVP) or 1-deamino-8-D-arginine-vasopressin (DDAVP) normalized the disturbed memory functions in DI patients. These peptides also improved memory functions in healthy individuals.

Administration, Intranasal↗
PubMed1982

[Results of electromyographical and mechanographical investigations in myotonia congenita (author's transl)].

Electrical and mechanical investigations in myotonia were investigated in 20 patients with myotonia congenita. At first the parameters of the myotonic muscle fiber discharges were determined, than the EMG-activity was estimated during slight and maximal force of voluntary muscle contraction and finally the electromyogram and the mechanogram were simultaneously registered after indirect stimulation of the muscle. The results show, that there is a correlation between the myotonic muscle fiber discharges and the EMG- and mechanical findings depending on the frequency of stimulation and the force of contraction. The parameters of muscles did not differ between the patients and the health persons after single stimulation. Repetitive supramaximal stimuli (15 Hz) showed a rapid decline of EMG-amplitude in the patients with myotonia congenita. The fall of amplitude was observed, as soon as myotonia fiber discharges occured. The duration of contraction was longer both in the phase of contraction and in the phase of relaxation. When the frequency of stimulation was increased (30 Hz), the fall of EMG-amplitude was more increased whereas the contraction and relaxation time decreased. The findings are interpreted by means of the author's own experimental results and are discussed in connection with the chloride-hypothesis.

Adolescent↗
PubMed1982

A new murine cell surface differentiation antigen (Leugp90) defined by a rat monoclonal antibody: cellular distribution and biochemical characterization.

Monoclonal antibodies to murine lymphocyte differentiation antigens were generated by fusing the mouse myeloma cell line X63-Ag8.653 with spleen cells derived from Lewis rats hyperimmunized with lymphoid cells from nude (C57BL/6) mice. One of these antibodies--designated 3MB1--recognizes a previously undescribed cell surface antigen. This antigen is expressed on 62% of spleen cells, 9% of thymus cells, and 98% of peritoneal macrophages. Virtually all LPS- and Con A-induced lymphoblasts carry this newly found antigen. The 3MB1 determinant is limited in its expression to leukocytes. It is not found in other tissues such as brain, liver, kidney, or on erythrocytes. Biochemical analysis reveals that the 3MB1 target antigen consists of a single chain glycoprotein with an approximate m.w. of 90,000.

Animals↗
PubMed1982

Electron microscopy of the subthalamic nucleus in the baboon. II. Experimental demonstration of pallido-subthalamic synapses.

The present study demonstrates the existence in the baboon of a powerful ipsilateral pallido-subthalamic projection, composed of myelinated fibers. These axons give rise to type I (F) terminals, including all subtypes identified by Hassler et al. (1982), and terminate on the perikarya of the subthalamic relay neurons, on proximal dendrites, and on somatic and dendritic spines. Endings on subthalamic interneurons could not be found. Following experimental lesions in the pallidum externum, these pallido-subthalamic neurons undergo distinctive changes characterized as "pale", "intermediate" and "dark" degeneration, the form of the degeneration depending on the survival times of 3, 4 and 5 days. The ratios between the individual types of degeneration may vary. The ultrastructural features of the pallido-subthalamic terminals, which are believed to be GABA-ergic (Fonnum et al., 1978), are different from those of the GABA-ergic striato-nigral connections (Kim et al., 1971). After pallidum externum lesions, the pale form of degeneration is found in a few instances in the contralateral subthalamic nucleus in the type IX mini-synapses and the type I (F) beak-shaped synapses. There is a considerable convergence of different afferents with specialized synapses on the somata, stem dendrites, and dendritic spines of the neurons of the subthalamic nucleus.

Animals↗
PubMed1981

Termination of cortical afferents on identified neurons in the caudate nucleus of the cat. A combined Golgi-EM degeneration study.

A combined Golgi/electron microscopic technique was used to investigate tne fine structure and synaptology of Golgi-stained spiny neurons in the caudate nucleus of the cat. In order to study the termination sites of cortical afferents on Golgi-stained spiny neurons, cortical fibres were caused to degenerate by making extensive cortical lesions 3 days prior to fixation of the animals. When examined in the electron microscope, perikarya of labelled spiny neurons have a round nucleus, a few mitochondria and microtubules, and a poorly developed Golgi apparatus and rough endoplasmic reticulum. Only rarely are axo-somatic contacts seen. Labelled dendrites exhibit a moderate number of microtubules and sometimes elongated mitochondria. Numerous labelled spines are seen in the vicinity of their parent dendrites. They are contacted by smaller type I and type III boutons and larger type IV boutons (Hassler et al. 1978). Large boutons filled with clear round vesicles establish symmetric contacts with labelled dendritic shafts. Degenerating boutons of cortical afferents are seen in contact with spines and, more rarely, with dendritic shafts of Golgi-stained spiny neurons. All degenerating boutons synapsing with labelled structures are found some distance from the cell body. No contacts of degenerating cortical boutons with the soma or with stem dendrites of Golgi-stained spiny neurons are found.

Afferent Pathways↗
PubMed1981

Anti-inflammatory effects of 13-Cis-retinoic acid. An in vivo study.

Sixteen patients with care acne conglobata, acne fulminans, acme tetrade were treated orally with 13-cis-retinoic acid, 1-2 mg/kg body weight for 12 weeks. A maintenance dose of 0.5 mg/kg in ten cases and the use of no further medication in six other cases for an additional 12 weeks followed. A 40% potassium iodide ointment was used on the upper back under occlusive dressing conditions to induce an inflammatory reaction. Four inflammatory parameters were assessed in all subjects before and during oral treatment: erythema (0-2+), edema (0-2+), papules (numbers), and pustules (numbers). All patients showed excellent improvement. Additionally, the inflammatory reaction in all patch-tests was significantly reduced: erythema from 1.13 to 0.34 (P less than or equal to 0.01); edema from 1.06 to 0.25 (P less than or equal 0.0005); papules from 6.75 to 1.86 (P less than or equal to 0.01); and pustules from 10.44 to 1.56 (P less than or equal to 0.0025). We suggest that 13-cis-retinoic acid acts as a strong anti-inflammatory agent in addition to its known function as a sebostaticum.

Acne Vulgaris↗
PubMed1981

[The influence of several membrane stabilizing drugs on the induced hereditary myotonia--a methodic way to test the effectiveness of drugs on myotonia (author's transl)].

The therapeutic effectiveness of several membrane stabilizing drugs was investigated on experimentally induced myotonia by 2,4-Dichlorophenoxyacetate (2,4-D) and in 20 patients with myotonia congenita. Procainamide and quinine showed a better antimyotonic effect in-vitro- as well as in-vivo-experiments on the cold blood muscle and the rat than Sparteine sulfate and Tachmaline (Ajmalin). The two last-mentioned drugs had nearly the same effect. Because of these experimental results only procainamide and sparteine sulfate were clinically used. Quinine was not used because of the well known side-effects. Mention is made of the fact, that the therapeutic effect depends on the dose or the concentration. The results support not only the theoretic considerations on the pathogenesis of myotonia but also recommend to carry out further pharmacological investigations with this method.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1981

[Electromyography and electroneurography in peripheral nerve lesions. Part II].

Electromyographical and electroneurographical examinations are indicated in the forefield of the surgical treatment for radicular syndromes, traumatic plexus and nerve lesions as well as compression or bottle-neck syndromes. The electrophysiological findings point out the neurogenic nature of the disturbance. They furthermore furnish statements with respect to the localisation, the extent, the kind and the prognosis of the lesions. The electromyographical and electroneurographical examination programme is determined by the anatomical innervation conditions and the questions that are of clinical interest. In case of radicular syndromes it is mainly the localisation with respect to the height of the root lesions that is of interest. In plexus lesions, the question regarding the reinnervation chance is usually to the fore. In primary nerve lesions, the question whether there is a partial or total nerve separation is above all of interest. In secondary nerve lesions and the bottle-neck syndromes it is usually necessary to determine the exact site of the lesions and the extent of the chronic compression damage. In this paper, these aspects ae discussed on the basis of the more important clinical pictures and practical hints for diagnosis and therapy are given.

Brachial Plexus↗
PubMed1981

[The prognostic significance of electromyographic and electroneurographic results in Landry-Guillain-Barré-Strohl polyradiculoneuritis].

On the basis of an analysis of electromyographic and electroneurographic findings in patients with polyradiculoneuritis Landry - Guillain - Barré - Strohl courses of the diseases with different prognoses are found. In pure demyelinisation processes, a rapid and complete restitution can be expected. The regression of the pareses, however, will show a delayed, frequently an incomplete onset when electrophysiologically and axon loss can be proved.

Adolescent↗