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Biomedical subjects

W Paulus

Publications and source records attributed to W Paulus.

At least 271 records · Page 15Linked to original sources
PubMed1990

Brain iron and ferritin in Parkinson's and Alzheimer's diseases.

Semiquantitative histological evaluation of brain iron and ferritin in Parkinson's (PD) and Alzheimer's disease (DAT) have been performed in paraffin sections of brain regions which included frontal cortex, hippocampus, basal ganglia and brain stem. The results indicate a significant selective increase of Fe3+ and ferritin in substantia nigra zona compacta but not in zona reticulata of Parkinsonian brains, confirming the biochemical estimation of iron. No such changes were observed in the same regions of DAT brains. The increase of iron is evident in astrocytes, macrophages, reactive microglia and non-pigmented neurons, and in damaged areas devoid of pigmented neurons. In substantia nigra of PD and PD/DAT, strong ferritin reactivity was also associated with proliferated microglia. A faint iron staining was seen occasionally in peripheral halo of Lewy bodies. By contrast, in DAT and PD/DAT, strong ferritin immunoreactivity was observed in and around senile plaques and neurofibrillary tangles. The interrelationship between selective increase of iron and ferritin in PD requires further investigation, because both changes could participate in the induction of oxidative stress and neuronal death, due to their ability to promote formation of oxygen radicals.

Aged↗
PubMed1990

Intracerebral distribution of mitochondrial abnormalities in 21 cases of infantile spongy dystrophy.

Using a monoclonal antibody to an inner mitochondrial membrane antigen and light microscopic immunohistochemistry, we investigated the distribution of increased immunostaining (mitochondrial anomalies, MA) on paraffin sections from 21 brains with infantile spongy dystrophy (Leigh's disease, 8; Canavan's disease, 4; Alpers' syndrome, 2; mixed spongy dystrophy, 7). Compared with an age-matched control group, MA were present in all cases of Leigh's disease (leptomeningeal and intracerebral endothelial and vascular smooth muscle cells, choroid plexus epithelia, ependymal cells, astrocytes or some neurons), in 2 cases of Canavan's disease and the Alpers' syndrome cases (astrocytes and occasionally some neurons). The MA were restricted to spongy areas in Canavan's disease and Alpers' syndrome, whereas they were distributed throughout the brain in Leigh's disease. In mixed spongy dystrophies the Leigh histology was associated with MA, but not the Canavan histology. Brains with Wernicke's encephalopathy (3 cases), adult infarction (3), and multicystic encephalopathy (5) showed no MA, but one with methylmalonaciduria did. Our results substantiate the classification of Leigh's disease as primary mitochondrial encephalopathy.

Adolescent↗
PubMed1990

A mitochondrial myopathy in an infant with lactic acidosis.

We describe a girl with mitochondrial myopathy, who presented with general muscle weakness, muscle hypotonia and motor retardation. The level of blood lactate and pyruvate was consistently increased. Enzymatic studies showed impairment of NADH-dehydrogenase activity (complex I of the respiratory chain) in skeletal muscle. Electron-microscopy of a muscle biopsy showed abnormalities of a mitochondrial myopathy. The girl, now aged 30 months, has been treated with riboflavine (vitamin B2) since the age of 14 months, and lactate and pyruvate levels have decreased to normal. The patient still shows mild muscle hypotonia and weakness, but good motor progress and normal cognitive development.

Acidosis, Lactic↗
PubMed1989

Intratumoral histologic heterogeneity of gliomas. A quantitative study.

Quantitative data for intratumoral histologic heterogeneity were obtained by investigating ten small and ten large punched samples from 50 unembedded supratentorial gliomas. The 1000 samples were diagnosed according to the World Health Organization (WHO) classification and six histopathologic features associated with malignancy were evaluated (cellular density, nuclear pleomorphism, necroses, histologic architecture, vessels, and mitoses), each with defined gradations. The slides were read independently by two observers. The initially high interobserver variability (grade, 22.2%; type, 10.3%; and tumor presence/absence, 7.1%) was for the most part due to intermediate grades and types and was reduced to 1.7% after mutual review. Small samples showed lower mean grade than large samples and more often absence of tumor (7.6% versus 2.4%). Of all gliomas, 48% showed differently typed samples, 82% differently graded samples, and 62% benign and malignant grades. Intratumoral heterogeneity was higher for the necroses than for the other histopathologic features. Our results underscore the importance of extensive tissue sampling.

Brain Neoplasms↗
PubMed1989

Differential effects of retinal target displacement, changing size and changing disparity in the control of anterior/posterior and lateral body sway.

When visual information is provided in addition to input from other sensory systems, normal body sway can be attenuated by about 50%. The essential visual cue is retinal target displacement, which increases as eye-target distance is reduced. As a result, both lateral and anterior/posterior (A-P) sway decrease as eye/target distance decreases. We have investigated the geometrical basis of lateral and fore-aft sway detection by vision, the latter provided by detection of change in disparity of the visual axis of both eyes and change in target size. Using known movement detection thresholds the largest possible distance for visual stabilization of posture can be calculated to be 34 m for lateral sway, and for fore-aft sway 1.50 m for change in disparity and 3.20 m for change in size. Visual stimuli were designed to selectively stabilize fore-aft sway either by change in size or by change in disparity. The experiments revealed that the theoretical prediction overestimates the efficacy of visual stabilization of lateral sway and underestimates the efficacy of fore-aft sway stabilization. It is proposed that microoscillations of the eye increase the threshold for detection of retinal target displacements, leading to less efficient lateral sway stabilization than expected, and that the threshold for detection of self motion in the A-P direction is lower than the threshold for object motion detection used in the calculations, leading to more efficient stabilization of A-P sway.

Form Perception↗
PubMed1989

Melanotic paraganglioma of the orbit: a case report.

A paraganglioma of the orbit in a 21-year-old woman is presented, containing oculo-cutaneous melanin in many tumor cells, occasionally adjacent to neurosecretory granules, and in macrophages. This tumor expands the list of neuroectodermal tumors with potential melaninization.

Adult↗
PubMed1989

Mitochondrial encephalomyopathy with pilovacuolar inclusion or phenocopy with mitochondrial artefact?

The case of a 33-year-old man with clinical features of mitochondrial encephalomyopathy is presented. He suffered from recurrent cerebral infarctions, cerebellar ataxia, deafness, retinopathy, weakness, and cardiac and renal disorders. Biochemical and light microscope investigations of skeletal muscle did not show any mitochondrial abnormality. Electron microscopy revealed the presence of a hitherto unreported peculiar "pilovacuolar" inclusion in numerous mitochondria, composed of an electron dense pile or rod within a vacuole, while globular or crystalline inclusions were absent.

Acidosis, Lactic↗
PubMed1989

Ragged-red fibres detected in paraffin sections by a monoclonal antibody to inner mitochondrial membrane.

An immunohistochemical method is reported using the M-II68 monoclonal antibody, which detects mitochondrial accumulations ("ragged-red fibres") in routinely processed (formalin-fixed, paraffin-embedded) muscle tissue. Ten cases with electron-microscopically and histochemically proven mitochondrial myopathy featured 4% to 24% ragged-red fibres. In a series of 50 muscle biopsies without mitochondrial myopathy, scattered ragged-red fibres (less than 0.1%) were present in a few normal and pathological muscles. The immunohistochemical method is specific for mitochondria, does not require frozen tissue and permits rapid examination of large areas.

Antibodies, Monoclonal↗
PubMed1989

Intracerebral malignant fibrous histiocytoma at site of a previously excised low grade glioma.

The case of a 42-year-old patient is reported who developed an intracerebral malignant fibrous histiocytoma at the site of an oligoastrocytic mixed glioma which had been excised 2 1/2 years previously. Reasons for the extreme rarity of intracranial malignant fibrous histiocytomas, the probability of a traumatic aetiology of this particular tumour, and the possible significance of intratumoural cells positive for glial fibrillary acidic protein (GFAP) are discussed.

Adult↗
PubMed1989

Meningio-angiomatosis.

A case is described of a boy five years old who suffered from left-sided muscular weakness since the first months of life and from absences since the second year of life. He died of valproate-induced hepatic insufficiency. Autopsy of the brain revealed meningio-angiomatosis, a rare but rather benign disorder usually characterized by narrow meningothelial proliferations abutting upon cortical plaques and exhibiting proliferations of small vessels with perivascular cuffs of fibroblast-like cells. The peculiarities were that the case lacked any leptomeningeal calcification - in line with the patient's age being the lowest so far reported for pathologically verified meningio-angiomatosis - and also exhibited intracortical clusters of mesenchymal cells that did not form vessels ("free fibroblasts"). Immunohistochemically perivascular cells were negative for S100, GFAP, desmin and factor-8-related antigen and were embedded in interstitial collagen of types III and VI as well as procollagen I, while "free fibroblasts" were surrounded by deposits of basement membrane collagen type IV. The results are consistent with a meningothelial origin of perivascular cells and "free fibroblasts".

Angiomatosis↗
PubMed1989

Postural sway during retinal image stabilisation.

Posturographic measurements using a piezoelectric platform were made in normal subjects while wearing a combination of spectacle and contact lens providing partial stabilisation of the retinal image (RIS). The amount of postural sway seen while wearing the device at rest is intermediate between the "normal vision" and "eyes closed" conditions, and increases with increasing amounts of RIS. However, when large active head-and-eye movements are performed, postural sway is dramatically increased when using RIS, and is then worse than while performing the same task in the "eyes closed" condition. It is concluded that patients who use the partial-RIS device for the treatment of severe oscillopsia may benefit only when performing tasks in which the head is relatively still, such as reading, writing or watching TV. It is also proposed that the partial-RIS device can serve as a model in normal free-standing subjects for the postural effects of oculomotor disorders.

Adult↗
PubMed1989

Visual postural performance in ametropia and with optical distortion produced by bifocals and multifocals.

Visual stabilization of posture depends strongly on the performance of the visual system and declines with experimentally induced reduction of visual image quality. We studied postural performance in subjects with median and high grade hyperopia or myopia. While body sway of median grade ametropic subjects increased slightly when measured without glasses, high grade ametropia showed no significant differences between postural performance with glasses on and off. We concluded that the increase in visual acuity when wearing glasses is outweighted by concurrent dioptric distortions such as size change and prismatic effects. In addition we could not find any difference between bifocal and multifocal lenses in their effect on sway when investigated in normals with either steady fixation or saccades or foveal pursuit.

Adult↗
PubMed1989

Histogenesis of stromal cells in cerebellar hemangioblastomas. An immunohistochemical study.

Fifteen cerebellar hemangioblastomas were examined by immunohistochemistry for expression of neuron-specific enolase (NSE) and various neuropeptides using the avidin-biotin-complex peroxidase reaction with the following antibodies: NSE, synaptophysin, serotonin, substance P, vasoactive intestinal peptide (VIP), neuropeptide YY, neurotensin, and leu-enkephalin. In all tumor biopsies most of the stromal cells were positive for NSE. About 30% of the stromal cells showed a weak cytoplasmic synaptophysin positivity. Approximately 25% of the stromal cells were labeled with antibodies against substance P and neuropeptide YY. The partly strong reactivity was localized preferentially in perinuclear regions. These positive cells were mainly distributed in small cell clusters but were also scattered in the tumor parenchyma. In all tumor biopsies scattered cells exhibited strong perinuclear enkephalin positivity, corresponding probably to mast cells, whereas stromal cells were entirely negative. For serotonin, VIP, and neurotensin no specific reaction was seen. On the basis of these findings it is proposed that hemangioblastomas have a neuroendocrine component.

Biopsy↗
PubMed1988

Adult-onset rod disease with abundant intranuclear rods.

The third case of adult-onset rod disease (nemaline myopathy) with abundant myofibrillar as well as intranuclear rods is described. The 61-year-old woman suffered from progressive weakness of proximal extremities and of the neck, mimicking polymyositis. Muscle biopsy revealed a striking myopathic pattern, with intranuclear rods occurring in 31% of the fibres. On light and electron microscopy and by immunohistochemical study, the rods differed from myofibrillar rods. The absence of alpha-actinin in intranuclear rods suggests an enhanced readiness of actin filaments to bind to diverse proteins, instead of overproduction of alpha-actinin as the pathogenetic basis of the rod formation.

Actinin↗
PubMed1988

Effect of musical modelling on late auditory evoked potentials.

Late auditory evoked potentials were recorded in four subjects during musical tasks. A PDP 12 computer synchronized stimuli, which were produced by an integrated circuit, and recording with the help of a quartz time basis. The content of each experiment was different modelling of an ambiguous identical acoustic stimulus. In experiment 1, subjects had to model a 6-note melody according to the classic metric foot. In experiment 2, segmentation of an 8-note melody into 5- and 3- versus 3- and 5-tone motifs had to be performed. In experiment 1 an intra-individually reliable, but inter-individually variable neurophysiological correlate was detected during the heavy tone: (1) positivity, (2) negativity, (3) alpha blocking and (4) DC shift. Experiment 2 yielded an intra- and inter-individually reliable positive DC shift of about 4 microV between the two motifs. Myogenic, ocular, dermal, respiratory or electrocardiographic artefacts were excluded in each case. The results indicate that conclusions from evoked potentials to musical perception might be possible and that possible modelling mechanisms with subsequent undesirable influence on recordings have to be considered in any kind of evoked potential experimental design.

Adult↗
PubMed1988

Does the pleomorphic xanthoastrocytoma exist? Problems in the application of immunological techniques to the classification of brain tumors.

A case of a fibrous xanthomatous tumor of the meninges is reported. This is a rare tumor of childhood in which the characteristic pleomorphic histology contrasts with the good clinical prognosis. These tumors were reclassified as pleomorphic xanthoastrocytomas (PXA) due to their glial fibrillary acidic protein (GFAP) positivity. In the present tumor, GFAP was absent from nearly all cell bodies in most of the leptomeningeal regions of the tumor but could be detected with greater frequency at the cortical-leptomeningeal border zones and in the areas in which the tumor had infiltrated the cortex. All the tumor cells expressed vimentin and in, addition, most expressed alpha-1-antitrypsin, alpha-1-antichymotrypsin, tartrate-resistant acid phosphatase, common leukocyte antigen, and OKM1. This spectrum of marker staining corresponded not only to the pattern observed in two cutaneous fibrous histiocytomas and one malignant fibrous histiocytoma, but also to the results previously published in the literature with regard to fibrohistiocytic tumors. By contrast, this spectrum of monocytic-histiocytic marker staining was not seen in gliomas. We, therefore, regard the PXA as a mesenchymal tumor of the meninges, identical to benign fibrous histiocytomas elsewhere in the body. The possible reasons why this mesenchymal tumor can show GFAP positivity in the leptomeningeal border zone are discussed.

Astrocytoma↗