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K Brauer

Publications and source records attributed to K Brauer.

At least 73 records · Page 4Linked to original sources
PubMed1989

The cholinergic nuclei of the basal forebrain of the hamster (Mesocricetus auratus): a combined Golgi- and AChE-topochemical investigation.

The cholinergic basal forebrain nuclear complex of the golden hamster was investigated Golgi-architectonically and AChE-topochemically using enzymehistochemical and immunohistochemical methods. We demonstrated 12 different classes of neurons in the whole basal forebrain complex with the Golgi-Kopsch-technique. The classical anatomical subdivision of the septal-region into nucleus medialis septi and nucleus tractus diagonalis has not been confirmed by results elaborated with this method. We found at least one class of neurons with varicose dendrites in every part of the cholinergic basal forebrain complex. The varicosities reacted positively for AChE. This morphological feature might be characteristic for cholinergic neurons in the nuclei of the basal forebrain complex.

Acetylcholinesterase↗
PubMed1989

[The classification of neurons in the corpus geniculatum laterale pars ventralis of the albino rat: a Golgi-Kopsch study].

Neurons in the ventral lateral geniculate nucleus of 120 rats of a wistar strain were investigated with the Golgi Kopsch technique. Various features, such as size of neurons, their dendritic fine structure and their localization inside the nucleus were used to find new aspects for the classification of vLGN neurons except geniculo tectal relay neurons (GTR neurons). The results of our detailed investigation are in accordance with the classification given by Brauer et al. (1984). The dendrites show different morphological surface specializations, as there are smooth and varicose dendrites besides the spiny ones. Medium-sized neurons are most variable in their dendritic structure. It can be assumed that they represent a heterogenous group. The density of spines in the neurons investigated is much lower than in GTR neurons.

Animals↗
PubMed1989

Shape and size of synaptic vesicles in different types of presynaptic profiles in the medial septal nucleus of the rat.

Long and short axis diameters of synaptic vesicles were obtained from 6 classes of presynaptic boutons found in the medial septal nucleus (MS) of the rat. The variability of vesicle size and shape was documented in diagrams and discussed with regard to their suitability as criteria of classification and their functional significance. The variability in shape, but not in size, of vesicles in synapses of Gray's type I is lower than of those in Gray's type II synapses.

Animals↗
PubMed1988

Topographic differences in retinal axons in the dorsal lateral geniculate nucleus of the rat: a quantitative reexamination using anterograde transport of horseradish peroxidase.

Retinal endings in the dorsal lateral geniculate nucleus (dLGN) of the rat were visualized by anterogradely transported horseradish peroxidase following injections in the optic tract. The morphological findings confirm the two types of retinal axons previously suggested by Golgi investigations. In the caudal third of the dLGN type 2b axons, with small dense clusters of boutons, are the only representatives of retinal fibres seen. In the rostral two thirds they are intermingled with the larger type 2a terminals, but tend to accumulate laterally, adjacent to the optic tract. This study supports the concept that large retinal ganglion cells probably give rise to 2a axons that may represent a Y-like channel, whereas 2b axons are derived from small ganglion cells, and may relay a W-like pathway.

Animals↗
PubMed1988

[Anatomy of the nucleus magnocellularis in the basal forebrain of rodents and rabbits].

1. We have investigated the topographic organization and the extend of the magnocellular nuclei in the basal forebrain in 7 species of rodents and in the hare and the rabbit. 2. These nuclei, extending in rostro-caudal direction and forming a more or less continuous complex, are termed as follows: Nc. tractus diagonalis with pars medialis septi, pars verticalis and pars horizontalis, Nc. praeopticus magnocellularis, Substantia innominata, Nc. basalis Meynert, large cells lying along the lateral, ventral and medial borders of the globus pallidus, within the nucleus ansae lenticularis and the nucleus entopeduncularis. 3. Despite the multiplicity of nomenclature used by several authors for the same or different species, the magnocellular basal forebrain complex is present in all mammalian species investigated up to now. 4. We found that the nucleus medialis septi is not a separate nucleus. As a part of the pars verticalis of the diagonal band it is a subdivision of this nucleus. Indications for this result are: Agreeing positions of the cells among the fibers of the diagonal band of Broca, identical types of neurons in Golgi-preparations, the same efferent projection regions (mainly hippocampus). 5. In most of the rodents the nucleus basalis of Meynert can not be recognized in Nissl-preparations. Large interdigitated, cells as well in the substantia innominata as in the boundaries of the globus pallidus may probably be homologous to those in this nucleus. 6. In the squirrel we observed an accumulation of large cells at the ventral border of the globus pallidus interpreting this as a nuclear formation homologous or analogous to the nucleus basalis of Meynert in primates. 7. The hare and the rabbit form also an accumulation of large cells interpreted as nucleus basalis of Meynert. A dense arrangement already can be seen in the magnocellular praeoptic nucleus. It continuous through the ventral pallidum and the substantia innominata to the ventral border of the globus pallidus. 8. To elucidate the interrelations between the formation of a distinct nucleus basalis of Meynert and the mesencephalization process in the mammalian phylogeny more comparative investigations are necessary.

Acetylcholinesterase↗
PubMed1988

Neurons in the basal forebrain complex of the rat: a Golgi study.

Several types of neurons are coexistent in the basal forebrain nuclear complex of the rat. In the medial septum and vertical limb of the diagonal band 3 classes of neurons occur which are characterized by varicose dendrites. In the horizontal limb of the diagonal band neurons with smooth dendrites and those with varicose dendrites are intermingled. We found 3 classes of neurons in the nucleus preopticus magnocellularis. A giant type with smooth and varicose dendrites occurs in this nucleus, but also in the substantia innominata. In the substantia innominata-nucleus basalis complex 4 classes of neurons with varicose dendrites and 2 classes with spiny dendrites have been observed. Our findings suggest that the nucleus of the vertical limb of the diagonal band forms a unit with the nucleus septi medialis, but is separated from the nucleus of the horizontal limb of the diagonal band by different neuronal composition. The nucleus preopticus magnocellularis is a separate nuclear structure characterized by a content of neurons different from those in the horizontal limb of the diagonal band and in most components also from the substantia innominata-nucleus basalis complex. There is some evidence that the cholinergic neurons have to be searched among those with varicose dendrites.

Animals↗
PubMed1987

Measurement of lung density by x-ray computed tomography. Relation to lung mechanics in workers exposed to asbestos cement.

We measured lung density by means of x-ray computed tomography and lung mechanics in 33 workers exposed to asbestos cement and in 39 normal subjects. The exposed group showed evidence of lung fibrosis with reduced static lung volumes and lung compliance, although only three subjects had signs of interstitial fibrosis at standard chest radiography. Lung density was significantly increased in the exposed workers compared to control subjects, with greater differences between nonsmokers than between smokers. Lung density correlated inversely with static lung volumes. There was no appreciable difference in the regional distribution of lung density between exposed workers and control subjects. We conclude that lung density is often increased in workers with mild asbestosis, even in the presence of a normal chest radiograph. Measurement of lung density may be of value in the evaluation of asbestos-exposed workers for assessment of the extent of parenchymal disease.

Asbestosis↗
PubMed1987

Cells with varicose dendrites: a characteristic type of neurons in Golgi preparations of the rat cholinergic basal forebrain nuclei.

Golgi preparations reveal that in the basal forebrain nuclei composed of medial septal nucleus, diagonal band, nucleus preopticus magnocellularis and substantia innominata including nucleus basalis magnocellularis of Meynert, the most frequently impregnated type of neuron is medium to large sized with long smooth or sparsely spined varicose dendrites. Some indications implying the cholinergic nature of those cells are discussed.

Animals↗
PubMed1986

Measurement of pulmonary density by means of X-ray computerized tomography. Relation to pulmonary mechanics in normal subjects.

We examined the relationship between pulmonary density, measured with computerized tomography, and pulmonary mechanics (static pulmonary volume; pulmonary resistance) in 39 normal subjects (20 nonsmokers and 19 smokers). Pulmonary density decreased with increasing static elastic recoil pressure, and smokers consistently showed higher pulmonary density than nonsmokers. Pulmonary density, measured at full inspiration, correlated inversely with total lung capacity. Pulmonary density showed a ventrodorsal gradient, which was greater at low elastic recoil pressure than at high recoil pressure. The study shows that pulmonary density is related to the mechanical properties of the lung in normal subjects. Increased pulmonary density appears to be a sensitive indicator of pulmonary damage induced by smoking. Further studies of the relationship between pulmonary density and pulmonary mechanics in disease seem warranted.

Aged↗
PubMed1985

Morphology of axons in the human lateral geniculate nucleus: a Golgi study in prenatal and postnatal material.

A study was made of rapid Golgi preparations from the lateral geniculate nucleus in humans aged from 28 weeks gestation to 70 years in order to identify axon terminals of afferent fibre systems. We describe three main axonal types using, as far as possible, nomenclature already adopted for other species. Type I axons were found only rarely. They are relatively straight with short, stalked side-branches and may represent cortico-geniculate fibres. Type II axons have complex, ball-like arborizations with large, irregular varicosities. They are common at all ages from gestation to maturity and are probably retinal in origin. Type IV axons (Type III was not used as no unequivocally intrinsic axons, for which the term has been used in the past, were identified) are branched, meandering and characterized by many, regular varicosities. Their origin is unclear, but may be related to non-specific brainstem sources. The basic morphology of Type II axons varies little between late gestation and adulthood, but Types I and IV seem to evolve during the perinatal period, perhaps from primitive forms that have similar morphological features. We conclude that the morphology of afferent axons to the human lateral geniculate nucleus is basically similar to that of lower mammalian species.

Adolescent↗
PubMed1985

Golgi and Nissl studies of the visual cortex of the bottlenose dolphin.

Nissl, Golgi and fibre preparations were made of the cerebral cortex of the lateral gyrus of the bottlenose dolphin (Tursiops truncatus) in the region where visual evoked potentials have been reported (Sokolov et al., '72; Ladygina et al., '78). In the adult the visual cortex is relatively thin (average about 1,300 micron) for so large a brain (fixed brain weight for a typical adult in our series was 1,330 g). Layers I, III, and VI are wide and represent three-quarters of the total cortical thickness. Layer I contains few cell bodies, while III and VI have a variety of pyramidal and nonpyramidal neurons. Layers II and V are narrow and contain striking palisades of darkly staining pyramidal cells that are particularly large in layer V. No clearly demarcated layer IV is present in the adult dolphin visual cortex. Many of the neurons identified with the Golgi technique are typical of pyramids in other mammals, with a single apical dendrite and a bouquet of basal dendrites, mostly highly spiny. Others are unusual in having bifurcated or oblique apical dendrites. Typical large and small spiny and nonspiny stellates are also found, mainly in layers III and VI. In addition various forms of spindle-shaped, bipolar and multipolar neurons are found in most layers. An 18-day-old brain shows signs of immaturity in its visual cortex. It is thinner (970 micron) and on average its neurons are smaller, paler, and more densely packed. Especially the pyramids of layer V are much smaller than in the adult. Also, a distinct "granular" band occurs between layers III and V and seems to be a rudimentary layer IV. At 3 years of age most of the adult features have developed, but layer IV is still detectable. No striking differences were observed in cell and fibre architecture between the cortex of the lateral gyrus and that of the so-called "calcarine" area that has also been considered as "visual." We concluded that, although different in many respects from other mammalian visual cortices, that of the dolphin is apparently well developed and differentiated.

Aging↗
PubMed1985

Ultrastructural development of the dorsal lateral geniculate nucleus of genetically microphthalmic mice.

The ultrastructure of the dorsal lateral geniculate nucleus (dLGN) of microphthalmic mice is described in affected white homozygotes (mi/mi) and their apparently normal grey littermates. In the dLGN of mi/mi animals populations of apparently normal axon terminals were observed, including some with flattened synaptic vesicles and other small terminals with round vesicles and dark mitochondria (RSD), possibly of cortico-thalamic origin, just as in normal mice. However, no typical large retinal endings with round vesicles and pale mitochondria (RLP) are visible. Instead they appear to be replaced by other large boutons with round vesicles and dark mitochondria (RLD). Eye enucleation does not cause degeneration of these RLD terminals. In apparently normal grey littermates RLP terminals are present and they degenerate when an eye is enucleated. But RLD endings are also found in these animals, and never degenerate after enucleation. The origin of the RLD terminals is unclear but seems not to be cortical. These findings are compared with those of Cullen and Kaiserman-Abramof (1976) in a different strain (ZRDCT-An) of anophthalmic mouse in which they found large replacement terminals similar to our RLD boutons.

Animals↗
PubMed1985

On the ontogenetic development of the rat dorsal lateral geniculate nucleus. I. GCR-neurons at postnatal day 7--a Golgi-electron microscopic study.

The morphology and synaptic input of four geniculo-cortical relay neurons of albino rats of postnatal day (PD) 7 has been studied with light and electron microscopy, utilizing the combined Golgi-EM technique. Although the nerve cells investigated did show a characteristic relay-cell appearance of the adult, certain dendritic structures exhibited immature character. These were the dendritic swellings, or "growth buds" occurring throughout the whole length of the dendrites, but particularly along the segments and at bifurcations of thin distal dendritic portions. These dendritic thickenings together with the transient spine-like hairy processes were seen to receive many synaptic endings of various developmental stages. The majority of synaptic junctions both on the dendritic swellings and on dendritic shafts were of the asymmetric type. Contrary to our expectation, no proximo-distal gradient could be demonstrated in the maturation of axodendritic synapses, at least not during the first synaptogenetic period, i.e., at PD 7. Also, all axosomatic synapses in the PD7 rat LGNd were asymmetric, indicating that the replacement of asymmetric synapses by symmetric ones (characteristic for the adult stage) occurs only after the first synaptogenetic period. The rarity of Gray II type, symmetric contacts during the early synaptogenesis (i.e., at PD 7) explains the absence of triadic, or serial synapses which will develop only later, during the second synaptogenetic period.

Animals↗
PubMed1985

Lung function in progressive systemic sclerosis is dominated by poorly compliant lungs and stiff airways.

Pulmonary function was investigated in 24 patients with progressive systemic sclerosis. The lung volumes were measured by a body plethysmograph. Bronchial and parenchymal properties were studied by relating pulmonary resistance and lung volume to pulmonary elastic recoil pressure. Pulmonary mechanics and arterial blood gases were studied during graded exercise on a bicycle ergometer. The most fundamental abnormality was a less compliant lung parenchyma together with lowered TLC, VC and ventilatory capacity. A mild intrinsic bronchial obstruction was found, irrespective of smoking habits. In 7 patients, resistance did not, however, increase towards residual volume as it does in normal subjects. This phenomenon is interpreted as stiff airways withstanding compression. Blood gas values at rest, and during work, were remarkably normal. There was no correlation between fibrosis judged from static lung compliance and from chest roentgenograms.

Adult↗
PubMed1985

[The lateral geniculate body of the guinea pig (Cavia aperea f. domestica). Its organization with reference to retinal afferents].

The lateral geniculate nucleus (LGN) of the guinea pig was studied in order to investigate the existence of an alpha- and beta-sector. On the basis of the fibre arrangement and the cell distribution in its rostral third the LGd can be subdivided into an alpha- and beta-sector. The caudal half of the LGd comprises the alpha-sector only. In contrast to the alpha-sector, in which the cells are densely packed, the beta-sector is rich in fibre bundles and contains a scattering of medium-sized cells. Following unilateral enucleation we observed degenerating fibres in the contralateral beta-sector, too. This confirms the assumption that this sector is a part of the dorsal LGN. Like most of the alpha-sector, the beta-sector receives fibres from the contralateral retina, therefore the two sectors can not be interpreted like laminae. A cytoarchitectonical lamination could not be observed. The ipsilateral input is concentrated in a specific zone of the GdL (dorsomedial) but there is an overlapping with the contralateral input in the alpha-sector. In contrast to rat and mouse were the fibres of the Radiatio thalami are bordering the medial region of LGN the fibre bundles of the Radiatio thalami in the guinea pig and in the rabbit are scattered and pass through the medial part of the LGd. Therefore a beta-sector is formed. Parallel observations are reported from different species of marsupials. More investigations are necessary in order to solve the question whether the alpha- and beta-sectors--firstly described by Rose (1935) in the LGd of the rabbit--in lagomorphs, rodents and marsupials are homologous.

Animals↗
PubMed1984

Structural and cytochemical features of perineuronal glial nets in the rat brain.

Perineuronal nets formed by glial cells could be visualized in different regions of the rat brain with Golgi methods. Although mostly their cellular origin was not detectable, in some cases the nets were found to originate from glial cell processes possessing characteristic features of microglia. Using the colloidal iron hydroxide binding method and carbohydrate binding lectins the perineuronal nets were shown to be enriched with anionic carbohydrate components. Some functional aspects of these structures have been discussed.

Animals↗