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H Hilbig

Publications and source records attributed to H Hilbig.

At least 19 recordsLinked to original sources
PubMed1998

Region- and age-dependent variations of muscle fibre properties.

The cytophotometric-morphometrical analysis of extensor digitorum longus and soleus muscles of 2.5 and 18 months old rats revealed regional and age-dependent differences in fibre type distribution, fibre area and fibre type related-enzyme activities which characterize contractility and metabolic profile. Variations along the longitudinal axis from the origin to the insertion and along three transversal axes from superficial to deep were found dependent on the muscle investigated. For example, the fibres of extensor digitorum longus muscle showed increased contractile and glycolytic capacities near insertion and the fibres of soleus muscle increased oxidative capacity in its middle part. Furthermore, the contribution of the fibre type that is dominant in a muscle (fast-glycolytic fibre type in extensor digitorum longus and slow-oxidative fibre type in soleus muscle) to the total number of fibres increased from origin to insertion by 15 and 30%, respectively. Along the superficial-deep axes the oxidative capacity of all fibres increased, the most in fast fibres of the soleus muscle by approximately 50%. In soleus muscle, a decrease of cross areas of all fibre types from superficial to deep was found, correlating negatively with the succinate dehydrogenase activity of the fibres. In extensor digitorum longus muscle the change in cross areas of slow-oxidative and fast-oxidative glycolytic fibres was dependent on the position of the transversal axis in the muscle. The results suggest that distribution patterns of fibre types and the metabolic make up of individual muscle fibres are adapted on the basis of local functional demands. In both muscles, higher numbers and increased oxidative capacity of fast-glycolytic fibres were found during ageing, but variations from superficial to deeper regions were irrespective of age.

Aging↗
PubMed1997

Conversion of biocytin labelled cells and structures for the confocal laser-scanning method.

The method for converting biocytin preparations of brain sections fills a gap in the application of confocal laser-scanning microscopy. Both neuronal and non-neuronal structures are converted. The background remains free of staining. The protocol can be applied to old and already existing biocytin-(diaminobenzidine)-nickel preparations which are then made accessible to evaluation with the laser-scanning microscope by the substitution of nickel with silver-gold. Sodium thiosulphate is used to remove the unbound silver. The reflection image of the laser-scanning microscopy provides more information than the transmission image.

Animals↗
PubMed1997

24-hour rhythmicity of NADPH-diaphorase activity in the neuropil of rat visual cortex.

In the present study we examined the daytime-dependent alterations of nitric oxide synthase in the visual cortex of the rat. For this purpose, the activity of the nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d), an enzyme equivalent to nitric oxide synthase, was measured histochemically in rat visual cortex at 0600, 1200, 1800, and 2400 h using a photometric scanning method. Our results show day-time-dependent changes of the NADPH-d activity in the neuropil of the visual cortex. This was highest at 0600 h and decreased between 1200 h and 1800 h (unimodal profile of circadian activity). The number of NADPH-d-positive neuronal somata was not found to vary at the different time points.

Animals↗
PubMed1997

Corpus callosum axons in the developing visual cortex of the gerbil revealed by DiI and Fluorogold.

The distribution of commissural neurons and terminals was revealed by DiI and Fluorogold injections in gerbils. The distribution of corpus callosum projections in visual cortical areas changes significantly during postnatal development of the gerbil. On postnatal days 5, 8 and 10, the animals do not show callosal projections. Widespread callosal endings are developed by postnatal day 15. This diffuse projection concentrates in strips at the border of area 17/18A in adult animals (postnatal day 20 and older).

Aging↗
PubMed1996

Hypoxia-dependent changes of enzyme activities in different fibre types of rat soleus and extensor digitorum longus muscles. A cytophotometrical study.

Using cytophotometry activity changes of succinate dehydrogenase, glycerol-3-phosphate dehydrogenase and myofibrillar adenosine triphosphatase were measured in 3 fibre types of soleus and extensor digitorum longus muscles under normal and experimental conditions. Fibres were typed by means of cytophotometrical data into slow-oxidative, fast-oxidative glycolytic and fast-glycolytic ones. After experimental hypoxia of 20 min duration a significant increase of enzyme activities was observed especially in slow-oxidative and fast-oxidative glycolytic fibres of both muscles, e.g. succinate dehydrogenase activity increased by 21% in these fibres of soleus muscle and by 23-26% in these fibres of extensor digitorum longus muscle. Moreover, an increase of glycerol-3-phosphate dehydrogenase activity by 10% in slow-oxidative fibres and by 28% in fast-oxidative glycolytic fibres and a 10-12% increased ATPase activity in all fibres of extensor digitorum longus muscle were measured. Treatment with Ginkgo biloba extract for 3 months before exposure to hypoxia resulted in increased adenosine triphosphatase activity in all fibres of both muscles and in decreased succinate dehydrogenase activity of slow-oxidative and fast-oxidative glycolytic fibres of extensor digitorum longus muscle. These results could be interpreted as a protective effect of Ginkgo biloba extract.

Adenosine Triphosphatases↗
PubMed1996

Autoradiographic and electron microscopic studies of retinal rosettes in genetically microphthalmic mice.

We report results obtained in the microphthalmic strain of mice 944. Heterozygotes appear normal, but they produce litters in which typically between 2 and 5 offspring exhibit microphthalmia and rosettes in the retina and the optic nerve. As a result these animals are blind. Our investigations using 3H-thymidine for autoradiographic estimation of postnatal cell proliferation and electron microscopy for detailed observation of the morphology of the rosettes show an increased proliferation of neuronal cells (more than 200%), especially in rosettes. In the rosettes a centrally located lumen exists in which cytoplasmatic processes can be found. In ultrastructural investigations these processes were identified as residues of the outer segments of photoreceptor cells.

Animals↗
PubMed1995

Postnatal development of NADPH-diaphorase/nitric oxide synthase positive nerve cells in the visual cortex of the rat.

The postnatal development of NADPH-diaphorase (NADPH-d)/nitric oxide synthase (NOS) positive nerve cells was studied in the visual cortex of rats on postnatal day 1, 5, 10, 15, 20, 30 and at the age of 1 year. NADPH-d was demonstrated enzymhistochemically and NOS immunohistochemically using a polyclonal antibody. NADPH-d is localized in nerve cell somata, dendrites, axons and blood vessels, whereas NOS immunoreactivity is only detectable in nerve cells. The identity of NADPH-d cells with those which contain NOS was proved in double labelling experiments in the cortex of rats on postnatal day 5, 15 and at the age of 1 year. The results of these experiments have shown that in the cortex of rats NADPH-d positive cells are identical with NOS-positive cells in the different stages. Therefore we have used NADPH-d histochemistry in all other postnatal stages as a marker for neurons which contain NOS. NOS positive nerve cells appear very early on postnatal day 1 in the intermediate (white matter) and subplate (layers V and VI) region as small undifferentiated neurons. During the following postnatal differentiation these neurons reached their typical morphology in the second week and appeared in all layers. Neurons in layers V and VI preceded those in the superficial layers. Nerve cells in the white matter seem to have their own differentiation pattern because they showed characteristic features of immaturated varicose dendrites for a longer time. The investigation of soma size with the computerized "Kontron Videoplan" system (Zeiss, Germany) showed the largest cell bodies on postnatal day 20 which then decreased towards adulthood. Between postnatal day 10 and 20 some NOS-positive neurons especially in the deep layers displayed symptoms of degeneration, like shrunken cell bodies, corkscrew and twisted dendrites. Furthermore, NOS-positive neurons in layer I are not detectable in adult neocortex. These observations could suggest that some NOS-positive cells in the cerebral cortex of rats may occur only transiently. Also in the neuropil some alterations in the localization of NOS positive axonal boutons were observed. On postnatal day 10 NOS negative cell somata were shadowy surrounded by boutons. During the further development from postnatal day 20 until adulthood this particular position was no longer visible. Beside the NOS cells which played a transient role, the majority of these cells survived to adulthood and are a morphological (Martinotti-cells with ascending axons) and chemical (GABAergic, NADPH-d/NOS positive, peptide containing cells) defined cell type in the neuronal network of the cortex of the rat.

Aging↗
PubMed1995

On the structure of the pretectal nuclei of the rat: an immunocytochemical and tracer study.

We have studied the distribution of the calcium-binding proteins parvalbumin, calbindin and calretinin, the NADPH diaphorase activity and the morphology of the commissural neurons, revealed by the stereotactic applications of fluorogold in the pretectal complex of the rat. The histochemical differentiation of the pretectal complex shows a complementary pattern of parvalbumin and calbindin containing cells. Only a few of the neurons in the pretectal complex contain calbindin. Calretinin immunoreactivity is scant and diffuse. The NADPH-diaphorase activity is restricted to neurons and terminals in the nucleus of the optic tract and the dorsal terminal nucleus. Due to numerous active fibers which traverse these nuclei they display a reticular appearance. Commissural neurons constitute 20% of the cell number of the pretectal complex and are restricted to the dorsal and lateral terminal nuclei.

Animals↗
PubMed1994

Interlayer neurones in the rat superior colliculus: a tracer study using Dil/Di-ASP.

Five different populations of interlayer neurones (ILNs) can be described after DiI/Di-ASP tracing in rat superior colliculus (SC). All of these labelled neurones preferentially lay in the rostro-medial part of the SC. Most of them are located in the stratum opticum and in the stratum griseum superficiale. Our results indicate that ILNs represent a minority of neurones in the superficial layers but may constitute a substantial population of neurones in the stratum opticum connecting the visual and the multimodal collicular layers.

Animals↗
PubMed1994

Morphological analyses of NADPH-diaphorase/nitric oxide synthase positive structures in human visual cortex.

Human visual cortex was studied using NADPH-diaphorase histochemistry and nitric oxide synthase immunohistochemistry. Large, strongly stained, sparsely spined non-pyramidal cells (average soma diameter: 16 x 16 microns) occur in layers II-VI, but are commonest in layers II-III. Small weakly stained multipolar cells (average soma diameter 3.6 x 4 microns, stellate like cells) in layers II-VI are concentrated in layer IV of areas 17 and 18. The density of these cells, measured with a computer assisted microscopy system is less in area 18 than 17. Large, strongly stained, predominantly horizontal cells (average soma diameter 12 x 19 microns) are localized in the underlying white matter. Axons of the large, strongly NADPH-diaphorase positive cells are thin and unbranched with fine boutons. These axons ascend to layer I. The large, strongly stained cells in layers II-VI we identify as Martinotti neurons. In layer I parallel unbranched positive fibres with some fine boutons run horizontally and build dense axonal plexuses together with the axons of Martinotti neurons. Axons of presumed extrinsic origin are morphologically different from NADPH-diaphorase positive intrinsic fibres. They show thick varicosities running in different directions and forming a network in layers III-VI. Basket like formations of these fibres were frequently observed in layers IV, V and VI. Other fibres seem to innervate blood vessels. Nitric oxide synthase was also demonstrated immunohistochemically by a polyclonal rabbit nitric oxide synthase antiserum. The morphology and distribution of the immunostained cells correspond with those seen with NADPH-diaphorase histochemistry. Double labelling experiments confirm the colocalization of NADPH-diaphorase and nitric oxide synthase in all demonstrated cells. Immunohistochemical demonstration of glial fibrillary acidic protein has shown that astrocytes are not involved in the NADPH-diaphorase/NOS system in the human visual cortex.

Aged↗
PubMed1994

Aberrant visual pathways in microphthalmic mice.

We report results obtained in the microphthalmic strain of mice 944. Heterozygotes appear normal, but they produce litters in which typically between 2 and 5 offspring exhibit microphthalmia. As a result these animals are blind. Our investigations using the fluorescent tracer DiI show that in microphthalmic mice there is a small compensation for the missing retinal input by terminals or axon collaterals originating in the somatosensory thalamus. These morphological findings agree with somatosensory responses recorded in the visual cortex (EEG recordings).

Animals↗
PubMed1991

[Neurons in the visual cortex of Microtus brandti].

Neurons were described in the visual Cortex of Microtus brandti, a Mongolian harmful rodent living in day-activity. We find following types of neurons in our Golgi-material: 1. spiny neurons: pyramidal and stellate neurons. 2. smooth or sparsely spined neurons: smooth, large neurons, sparsely spined small neurons with descending axons, sparsely spined neurons with ascending axons. Double-bouquet-, chandelier and neuroglioforme cells are not impregnated. There are no bipolare neurons (Martinotti cells) among the neurons with ascending axons. The small, sparsely spined neurons are not only in lamina IV - like in other species - but they can also be found in laminae II to IV. Their distribution of spines on the distal parts of dendrites seems to be characteristical for rodents. The lamination of the visual cortex of Microtus brandti is the same like in the rat. All cells are of large size in relation to the body mass of the animal.

Animals↗
PubMed1991

[The structure of the superior colliculus in the microphthalmic mouse strain 944].

The structure of the superior Colliculus (CS) in congenitally blind mice was compared with that in healthy control mice. Thus Nissl staining and degeneration experiments were done resulting in differences in the Stratum opticum (SO) of the CS between microphthalmic and control mice. In microphthalmic mice the volume of SO decreases in 14% and packing density of neurons increases in 20% in comparison with controls. Terminal degeneration after lesion of the ipsilateral visual cortex is seen in the surface laminae only. This connection seems independent of visual signals.

Animals↗
PubMed1990

Development of visual callosal projection in the microphthalmic stain of mice 944.

The strain of mice 944 produces a recessive microphthalmy. The microphthalmic mice were compared with phenotypically healthy animals of the same litter and with 944-mice bilaterally enucleated at 1. postnatal day (pd). Comparison was done at the 5., 10., 15. and 20. pd after lesion of the right visual cortex 24 hours before. Therefore Nissl- and Fink-Heimer-series were prepared. The results are the following: At 20. pd microphthalmic mice show both retrograde and anterograde degeneration after lesion. Enucleated and control mice produce destroyed fibres only. This evidence of callosal projection in visual cortex is possible exclusive at pd 20 with satisfying results. The neurons of laminae II and III project in the animals with a normal visus exactly to the contralateral 17/18a borderline. Enucleated mice show in area 18a two or three stripes more reaching laterally. Microphthalmic mice have terminals in both area 17 and 18a.

Animals↗
PubMed1989

[Comparison of relay neurons in the lateral geniculate body of normal, bilaterally enucleated and congenitally blind strain 944 mice during ontogenesis].

Mice with normal visus, bilaterally enucleated and congenitally blind mice of the strain 944 were used to determine following parameters in the CGLd on day 5, 10, 15 and 20 post natum (Golgi impregnation): size of neurons (perikarya, size of dendritic domains DF), structure of dendrites (number of dendrites FDE, branching points VZP, distribution of dendritic density in relation to the perikaryon Is, number of primary dendrites). After Nissl staining the following parameters were investigated: volume of the CGLd, packing density and total number of cells in the CGLd. The differences between the three investigated groups of animals increase in changing amounts during the ontogenesis. The caudal part of the CGLd is altered mostly by the lacking optic events. Suppression of visual events during the normal ontogenesis caused by genetic defect or enucleation attacks the same structures of the neuron.

Aging↗
PubMed1989

[Volumetric and golgi studies of the corpus geniculatum laterale pars dorsalis of Alticola stoliczkanus barakshin and Alticola argentatus semicanus].

The dorsal lateral geniculate bodies (dLGB) in Alticola stoliczkanus barakshin, the Gobi-Altai-Mountain vole, and in Alticola argentatus semicanus, the silver grey mountain vole, and investigated using the nissl- and the golgi method. The geniculo-cortico-relay neurons (GCR neurons) of both species have 5 primary dendrites (D1), a dendritic field of about 100 micron, about 17 free dendritic distal parts (FDE), 10 branching points (VZP) and a average of the perikaryon of 10 micron. All tufted neurons are small and topographically distinctly localised. The dLGB's volume of Alticola stoczkanus, barakshin is 0.16 mm3, the dLGB's volume of Alticola argentatus semicanus is 0.23 mm3.

Animals↗