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Biomedical subjects

H Braak

Publications and source records attributed to H Braak.

At least 127 records · Page 7Linked to original sources
PubMed1989

The human oral raphe system. Architectonics and neuronal types in pigment-Nissl preparations.

Serial sections (15 microns, 120 microns, and 400 microns) of nine brain stems treated with a combined lipofuscin pigment-Nissl stain were examined in order to delineate the three-dimensional conformation and subdivisions as well as the neuronal types of the human oral raphe system. Characteristic lipofuscin deposits within the somata of various cell types facilitated the demarcation of the oral raphe nuclei from surrounding structures. The dorsal, central, and linear raphe nuclei, e.g. the major subdivisions of the oral raphe system, share common traits as far as neuronal composition and pigmentation is concerned. The interfascicular subnucleus, the dorsofascicular subnucleus, and the intercalate subnucleus are minor subdivisions of the dorsal raphe nucleus. The intercalate one cannot be differentiated from surrounding areas in preparations solely stained for Nissl-material, while it can facilely be identified in combined pigment-Nissl preparations by virtue of differences in the pigmentation pattern. Our architectonical concept of the oral raphe system is in good accordance with the one derived from immunocytochemical investigations of serotonin-containing neurons in the human brain stem. Furthermore, five main neuronal types are described which constitute the oral raphe nuclei. They have been differentiated according to their characteristics as seen in combined pigment-Nissl preparations. I) Large ovoid to polygonal neurons with densely packed and intensely stained pigment granules. II) Similarly featured cells displaying dust-fine and faintly stained pigment granules. III) Medium-sized, ovoid to polygonal neurons with loosely distributed, small pigment granules. IV) Small ovoid neurons devoid of pigment or with only few, intensely stained granules. V) Small spindle-shaped nerve cells with various amounts of intensely stained pigment granules.(ABSTRACT TRUNCATED AT 250 WORDS)

Autopsy↗
PubMed1989

Alzheimer's disease: areal and laminar pathology in the occipital isocortex.

Sensitive and specific silver methods for demonstration of (1) amyloid and/or precursors of amyloid and (2) neurofibrillary changes were applied to examine the pathology revealed by the occipital isocortex in cases of Alzheimer's disease and age-matched controls. In general, amyloid and/or precursors of amyloid are encountered in plaque-like formations. Large numbers of amyloid plaques occur in layers that only occasionally harbor neuritic plaques. Amyloid deposits can be found in abundance in the occipital cortex of demented individuals exhibiting an only sparse number of neuritic plaques. In demented individuals the striate area contains almost as much amyloid as the parastriate area or the peristriate region. Neurofibrillary changes are encountered in neuritic plaques, neurofibrillary tangles, and neuropil threads. Neuritic plaques are predominantly found in layers II and III. Their density changes even within the boundaries of architectonic units. Large numbers of plaques are found in the cortex covering the depth of the sulci. The number of neurofibrillary tangles increases abruptly when passing the striate/parastriate and the parastriate/peristriate boundaries. The neuropil threads may densely fill a layer without the presence of neurofibrillary tangles (layer V of the striate area). Neuropil threads contribute a substantial part to the total amount of the intraneuronally deposited pathological material.

Aged↗
PubMed1989

Alzheimer's disease: amyloid plaques in the cerebellum.

Two specific silver-staining methods demonstrating either extracellular amyloid and/or precursors of amyloid or intraneuronal neurofibrillary changes were used to examine cerebellar pathology in cases of presenile and senile dementia of the Alzheimer type, cases of Down's syndrome, and non-demented controls. The sensitivity of the techniques permitted visualization of large numbers of amyloid deposits in the cerebellar cortex of demented individuals. Similarly large numbers of amyloid deposits were not found in the cerebella of non-demented individuals. Neurofibrillary changes were absent. The majority of amyloid plaques occurred in the molecular layer. Quite a number of these displayed large diameters extending from the upper surface down to the Purkinje cell layer. Within the granular layer and white matter the plaques were less frequently encountered and they were less voluminous than those of the molecular layer. The cerebellar amyloid plaques were morphologically different and could easily be distinguished from the cerebellar plaques found in transmissible spongiform encephalopathies.

Adolescent↗
PubMed1989

Neuronal types and their percent distribution within the magnocellular nuclei of the human basal forebrain.

Three neuronal types constituting the magnocellular nuclei of the human basal forebrain have been differentiated with the aid of preparations stained for both Nissl material and pigment deposits: type I = large multipolar neurons contain loosely packed and faintly stained lipofuscin granules occupying a large portion of the cell body; type II = large spindle-shaped neurons reveal a densely packed accumulation of coarse and intensely stained lipofuscin granules, and type III = small nerve cells, scattered among these large neuronal components, with only a small number of faintly stained lipofuscin granules. The determination of the projection areas of the somata of the three neuronal types has led to a distribution pattern with three peaks. The ratio of the nerve cell types has been evaluated: 73.6% type I; 8.6% type II, and 17.8% type III neurons.

Basal Ganglia↗
PubMed1989

Changes within the basal nucleus in Parkinson's disease.

The magnocellular nuclei in the basal forebrain--the medial septal nucleus, the nucleus of the diagonal band, and the basal nucleus within the substantia innominata--are tightly connected with each other. Large multipolar neurons clearly predominating in number can be differentiated from a spindle-shaped and a small globular type of neuron on account of their typical pattern of lipofuscin pigmentation. As an additional feature some of the multipolar neurons exhibit intracytoplasmic acidophilic granules. At the ultrastructural level, these granules reveal a homogeneous substructure, and they are occasionally located within mitochondria. The percentage of large multipolar neurons displaying acidophilic granules varies in a topographical manner (medial septal nucleus and vertical limb nucleus of the diagonal band: 10%, horizontal limb nucleus of the diagonal band and anteromedial subnucleus of the basal nucleus: 36%, posterolateral subnucleus of the basal nucleus: 54%). In parkinsonian cases a significant decrease of granule-bearing neurons within the posterolateral subnucleus of the basal nucleus is noted. This decrease might be associated with the appearance of neurons containing Lewy-bodies. It is also conceivable that the granule-bearing neurons show a higher vulnerability and underlie neuronal death. Analyzing the lipofuscin pigmentation within the two subnuclei of the basal nucleus in parkinsonian cases, one notices that the number of large multipolar neurons displaying pigment granules in a dendritic stem is significantly higher than in controls. Moreover, it is apparent that the degree of this pigment penetration is more pronounced in cases of Parkinson's disease. These alterations may be interpreted as a sign of plasticity of this neuronal population.

Basal Ganglia↗
PubMed1988

Somatostatin-like immunoreactivity in non-pyramidal neurons of the human entorhinal region.

The distribution of somatostatin-immunoreactive cells and processes throughout the human entorhinal region and subjacent white matter was examined either by the unlabelled antibody-enzyme method or by the avidin-biotin method. The brain slices were obtained at autopsy with a short post-mortem delay. The majority of somatostatin immunoreactive nerve cells was found in the inner principal layer and subjacent white matter. In addition, individually scattered immunoreactive neurons were observed in both the outer principal layer and lamina dissecans. The immunoreactive perikarya varied in shape and ranged in size from 10 to 30 micron. Without exception the neurons could be classified as belonging to the group of non-pyramidal neurons. Each neuron gave rise to a few thick dendrites and a thin axon with a beaded appearance. In the adult human brain, the pattern formed by lipofuscin granules deposited in the nerve cells can be considered characteristic for the type of the neuron. Therefore, immunoreactive perikarya were documented, destained of chromogen and restained to demonstrate lipofuscin pigment and basophilic substance. It became evident from these studies that the previously immunoreactive cells were characterized by a large rounded and eccentrically located nucleus, sparse basophilic substance and, in most cases, a lack of lipofuscin granules. A few of the immunoreactive cells were laden with coarse pigment granules. The findings permit classification of entorhinal somatostatin-immunoreactive neurons as either non-pigmented or pigment-laden non-pyramidal neurons.

Aged↗
PubMed1988

The pigmented subpeduncular nucleus: a neuromelanin-containing nucleus in the human pontine tegmentum. Morphology and changes in Alzheimer's disease.

A nuclear gray is found in the human pontine tegmentum close to the lower circumference of the superior cerebellar peduncle and is located within the pedunculo-lemniscal trigone. It is mainly characterized by the presence of medium-sized neuro-melanin-containing neurons and, therefore, referred to as the pigmented subpeduncular nucleus. Three basic neuronal types occur within the boundaries of the nucleus. Scattered among the neuromelanin-containing type I nerve cells are type II cells with lipofuscin deposits and type III neurons devoid of any pigmentation. In cases of Alzheimer-type dementia, the pigmented subpeduncular nucleus shows severe changes. Neurofibrillary tangles can frequently be found within the somata of both the melanin-laden and the lipofuscin-containing neurons. In contrast, the non-pigmented nerve cells remain devoid of such pathological filaments. Furthermore, large numbers of neuropil threads are scattered throughout the nuclear gray.

Alzheimer Disease↗
PubMed1988

Silver impregnation of Alzheimer's neurofibrillary changes counterstained for basophilic material and lipofuscin pigment.

A method is described in which selective silver staining of Alzheimer's neurofibrillary changes is combined with staining of cell nuclei, Nissl material, and lipofuscin granules. Formalin fixed, paraffin embedded sections of human autopsy tissue are silver stained according to a method proposed by Gallyas. Lipofuscin is stained by crotonaldehyde fuchsin following performic acid oxidation. Nissl substance is visualized by either Darrow red or gallocyanin-chrome alum staining. Architectonic units showing the specific pathology and the neuronal types prone to develop the neurofibrillary changes can be recognized using this technique.

Alzheimer Disease↗
PubMed1987

Argyrophilic grains: characteristic pathology of cerebral cortex in cases of adult onset dementia without Alzheimer changes.

Brains from 56 individuals suffering from adult onset dementia and devoid of macroscopically detectable infarctions were examined. Forty brains showed the characteristic cytoskeleton changes of Alzheimer's disease. Eight brains failed to reveal considerable numbers of neuritic plaques, neurofibrillary tangles, and neuropil threads, but these brains showed the presence of abnormal and intensely argyrophilic grains loosely scattered throughout the neuropil. Abundant numbers of these small spindle-shaped grains were encountered within the pyramidal layers of CA1 and layer Pre-beta of the entorhinal region. Eight brains showed both the argyrophilic grains and the neurofibrillary changes of the Alzheimer type. The appearance of argyrophilic grains within the neuropil is considered a morphological substrate of an unknown disease associated with adult onset dementia.

Aged↗
PubMed1987

The hypothalamus of the human adult: chiasmatic region.

The human hypothalamus can be divided into a chiasmatic region, a tuberal region, and a mamillary region. The chiasmatic region comprises the magnocellular neurosecretory nuclei, several nuclei that are mainly formed of small nerve cells, and an ill-defined nerve cell assembly referred to as the chiasmatic gray. Small to medium-sized bipolar nerve cells predominate in the chiasmatic gray. With the use of Nissl preparations counterstained for demonstration of lipofuscin pigment, four types of neurons have been distinguished. Type I cells contain coarse and intensely stained lipofuscin granules. Type II cells are characterized by dense accumulations of small granules. Type III neurons harbour only a fine scattering of dust-like granules while type IV neurons are devoid of pigment. Pigmentoarchitectonic analysis of the chiasmatic region reveals the presence of eight nuclei embedded in or partially surrounded by the chiasmatic gray. The intermediate nucleus is a small compact accumulation of non-pigmented nerve cells located at the level of the optic chiasm half way between the paraventricular nucleus and the supraoptic nucleus. The periventricular nucleus and the uncinate nucleus are mainly formed of small pigment-laden type I and type II cells and appear as an anterior, respectively lateral extension of the paraventricular nucleus. Besides non-specific small cells, three neuronal types can be distinguished in the paraventricular nucleus on account of characteristic differences in their pigmentation. The supraoptic nucleus is formed of only two types of nerve cells. The cuneiform nucleus extends from the supraoptic nucleus to the ependymal lining of the third ventricle separating the suprachiasmatic nucleus from the retrochiasmatic nucleus. The suprachiasmatic nucleus contains the smallest neurons of the region. Cells of this nucleus are devoid of lipofuscin pigment. The retrochiasmatic nucleus is formed of a heterogeneous population of small and unusually large nerve cells. Numerous melanin-containing nerve cells and accumulations of nerve cells belonging to the lateral tuberal nucleus can be encountered within the boundaries of this nucleus as well. The technique and the data presented provide a basis for investigations of the aged and the diseased human brain.

Adolescent↗
PubMed1987

Olfactory bulb changes in Alzheimer's disease.

Olfactory bulbs in cases of Alzheimer's disease and age-matched controls have been examined by means of combining silver staining of pathological filaments with pigment-Nissl staining of the cell bodies. Neuritic plaques were found in the anterior olfactory nucleus. Neurofibrillary tangles and neuropil threads occurred in the anterior olfactory nucleus and in all layers of the olfactory bulb except the outer fibrous layer. The tangle-bearing neurons of the olfactory bulb were identified as tufted cells, outer granule cells, and two different types of nerve cells forming the rostral part of the anterior olfactory nucleus.

Alzheimer Disease↗
PubMed1986

Occurrence of neuropil threads in the senile human brain and in Alzheimer's disease: a third location of paired helical filaments outside of neurofibrillary tangles and neuritic plaques.

Paired helical filaments, pathologically changed components of the cytoskeleton of human nerve cells, are demonstrated by a specific silver staining technique, immunostaining and electron microscopy. Accumulations of these filaments are found in the telencephalic cortex of old-aged individuals and patients suffering from Alzheimer's disease. Apart from neurofibrillary tangles and neuritic plaques, paired helical filaments are encountered in neuropil threads. At this third location, pathological filaments occur in small and inconspicuous profiles scattered throughout both allocortical and isocortical areas. The pattern of distribution and packing density of neuropil threads varies between different cortical areas and layers.

Aged↗
PubMed1986

Glutamic acid decarboxylase immunoreactivity in sector CA1 of the human Ammon's horn.

The distribution of glutamic acid decarboxylase (GAD) immunoreactive neurons, fibres and punctae in sector CA 1 of the adult human Ammon's horn was studied in Vibratome sections (40 micron thick) of tissue obtained at surgery and autopsy. On light microscopical examination, the material did not show pathological changes. The antibody was visualized by the unlabelled antibody enzyme method. GAD-immunoreactive neurons, fibres and punctae were present in all layers. Most immunoreactive neurons were located in the stratum pyramidale and stratum lacunosum. Their size ranged from 8 microns in the stratum lacunosum to about 50 microns in the stratum oriens. The somata offered a wide range of shapes, multiform to fusiform with the long axis aligned parallel or vertically to the alveus. All somata belonged to the heterogeneous group of non-pyramidal neurons. The dendrites either radiated in all directions or tended to run in two opposite directions. After bleaching the chromogen and staining for lipofuscin pigment granules and basophilic material, it turned out that within the stratum pyramidale all formerly GAD-immunoreactive neurons belonged to the group of lipofuscin-laden non-pyramidal neurons. Within the other layers, a few formerly GAD-immunoreactive neurons were devoid of lipofuscin pigment. The highest density of GAD-immunoreactive punctae was found in the stratum lacunosum. In addition to numerous GAD-immunoreactive punctae in the pyramidal layer and in the stratum radiatum there were thin GAD-immunoreactive fibres of varying length extending into various directions.

Adult↗
PubMed1986

Nuclear configuration and neuronal types of the nucleus niger in the brain of the human adult.

The pigmentoarchitectonic analysis of the human nucleus niger reveals three main territories: Pars compacta, pars diffusa and pars reticulata. Seven subnuclei are recognized within the pars compacta. The nerve cell types forming the nucleus niger were investigated using a Golgi de-impregnation technique in combination with counterstaining of intraneuronally deposited pigment granules. Three principal types of neurons were defined: Type I was a medium-sized to large neuron, mainly encountered in the pars compacta, giving off a few thick and sparsely branching dendrites. These cells were richly endowed with elongated patches of Nissl material that were mainly found in the peripheral portions of the dendrites. One pole of the cell body contained tightly packed neuromelanin granules. Type II neurons were mainly found in the pars reticulata. They were variable in size and shape and generated, similar to type I neurons, extended and sparsely branching dendrites. Type II neurons were devoid of neuromelanin. A considerable number of these cells were lacking in lipofuscin deposits as well. Type III neurons occurred in all portions of the nuclear complex. The small cell body gave rise to a few thin and spineless dendrites. The axon and filiform processes of the dendrites showed small varicosities irregularly spaced apart. The pale cytoplasm contained small and intensely stained lipofuscin granules, which did not tend to agglomerate. Intraneuronally deposited neuromelanin and lipofuscin pigment can be considered a natural marker of the neuronal type in the nucleus niger of the human adult. The technique and the data provide a basis for investigations of the aged and the diseased human brain.

Adult↗
PubMed1985

Somatostatin-like immunoreactivity in non-pyramidal neurons of the human isocortex.

The distribution of somatostatin-immunoreactive cell bodies and axons throughout the human isocortex and subjacent white matter was examined. Vibratome sections of cortical tissue (30-40 micrometers thick) obtained at surgery were treated to reveal the antigen by the unlabelled antibody enzyme method. Two types of somatostatin-immunoreactive axons were present: short, coiled axons and extended ones that follow a straight course in various directions. Somatostatin immunoreactive nerve cell bodies were encountered in layers II-VI and in the subjacent white matter. The majority of labelled cells were found in the white matter and layer VI, and then in layers II and III. The immunoreactive perikarya were fusiform, triangular or multipolar in shape and did not show preferential orientation of their long axis. Frequently, the fusiform neurons in layer VI and in the white matter were aligned parallel to radiate bundles of myelinated fibres. The immunoreactive neurons gave rise to a few thick dendrites. Often thin axon-like processes could also be recognized, originating either from the cell body or from a thicker dendrite. After destaining of the chromogen and counterstaining with aldehydefuchsin and gallocyanin chromealum, the formerly immunoreactive neurons displayed a light and eccentrically located nucleus. The soma contained only a sparse amount of basophilic substance and was nearly devoid of lipofuscin granules. In electron micrographs, the cisterns of the rough endoplasmic reticulum (RER) were localized near the periphery of the soma. Immunoreactivity occurred along membranes of the RER cistern, outer mitochondrial membrane, and in particles 120-150 micrometers in diameter. Rounded areas (up to a diameter of 1 micrometer) lacked immunoreactivity. Furthermore, there were a few tiny lysosomes.

Adult↗
PubMed1985

On areas of transition between entorhinal allocortex and temporal isocortex in the human brain. Normal morphology and lamina-specific pathology in Alzheimer's disease.

The allocortical entorhinal region does not gradually transform into the temporal isocortex. Instead, there is an extended stretch of "transentorhinal" cortex with interdigitation of allocortical and isocortical laminae. The main feature of this transition zone is that the superficial layer of large multipolar nerve cells (Pre-alpha) of the entorhinal region gradually sweeps downward and follows an oblique course through the outer layers. During this course the star-shaped nerve cells of Pre-alpha are transformed into pyramidal cells. The layer Pre-alpha projection cells are particularly prone to the development of neurofibrillary changes of the Alzheimer type. In cases of presenile and senile dementia almost all of the layer Pre-alpha projection neurons are changed pathologically. The isocortical pyramidal cells of layers II to IV are far less inclined to develop neurofibrillary changes. In the transentorhinal cortex, the tangle-bearing neurons follow an oblique course through the superficial laminae and are finally located between the isocortical layers III and IV, findings that confirm the assumption that these neurons are constituents of the allocortical layer Pre-alpha. Layer-specific pathology of the profound stratum as well confirms the transentorhinal region as being formed by interdigitating allocortical and isocortical layers.

Adult↗
PubMed1985

Ratio of pyramidal cells versus non-pyramidal cells in sector CA1 of the human Ammon's horn.

Combined Golgi/pigment studies revealed that pyramidal neurons and non-pyramidal cells of the Ammon's horn of the human adult can be distinguished from each other by their characteristic lipofuscin pigment deposits. In sector CA1, both the typical pyramidal neurons and the modified forms of pyramidal cells contain a modest amount of fine lipofuscin granules while non-pyramidal cells are either pigment-laden or devoid of lipofuscin deposits. Strips running through the whole depth of the pyramidal cell layer and the stratum oriens of CA1 were examined and all nucleolated nerve cells present within these strips were classified and counted (16 brains, age range from 28 to 69 years). Of the 18,510 neurons classified, 16,765 were pyramidal cells, including their modified versions, and 1,745 were non-pyramidal cells. The pyramidal cells, accordingly, were intermixed with 9.4 +/- 1.0% non-pyramidal neurons. The data presented provide a basis for investigation of the aging and diseased human brain.

Adult↗