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R Schober

Publications and source records attributed to R Schober.

At least 73 records · Page 4Linked to original sources
PubMed1978

The fine structural localization of acetylcholinesterase in the muscle spindle of the rat.

Muscle spindles from lumbricalis muscles of the rat were incubated for acetylcholinesterase with a modified thiocholine-method of Lewis and Shute and examined by light ane electron microscopy. All types of motor nerve ending showed heavy deposits of reaction product in the synaptic cleft. The underlying sarcoplasmic reticulum, transverse tubular system, and, when present, the envelope of sole plate nuclei were also stained. In the sensory region, the reaction was negative in the interface between the plasma membranes of the primary sensory terminal and muscle. One of two secondary sensory endings identified showed distinct reaction product in the cleft; the other secondary sensory ending showed no such reaction. Precipitates were present on the sarcolemma of the intrafusal muscle fibers in the polar and adjacent myotube regions, but not at the spindle equator. Extrafusal and intrafusal myelinated gamma-nerve fibers and preterminal motor axons showed staining of the axolemma. Fibers with thick myelin sheaths and preterminal sensory axons were free of acetylcholinesterase activity, as were the unmyelinated nerve fibers.

Acetylcholinesterase↗
PubMed1977

Demonstration of binding sites for divalent and trivalent ions on the outer surface of chromaffin-granule membranes.

1. Trivalent ions Tb3+, Eu3+ and La3+ aggregate chromaffin granules and produce structural changes in the core material. These ions also stain the outer (cytoplasmic) surface of the granule membrane in the presence of PO43+ ions and inhibit OSO4 staining. The electron-dense patches of TbPO4 complex are distributed in a non-random fashion. 2. Tb3+ also functions as a fluorescent membrane probe for divalent ion binding sites on the granule membrane. Using the enhancement of Tb3+ fluorescence upon binding, a Kd for Tb3+ of approximately 15 micronM was measured. Ca2+ and Mg2+ are competitive inhibitors of this binding while Na+ and K+ had no effect. Results suggest that the fluorescent Tb3+ -binding site is a protein. 3. Tb3+ also binds to mitochondria and other contaminants as judged by electron microscopy. However purified mitochondria show qualitatively different binding of Tb3+ by fluorescence. 4. A model for the location of divalent ion binding sites on the granule membrane and the results are discussed in terms of requirements for the participation of these sites in granule exocytosis in vivo.

Animals↗
PubMed1977

Calcium-induced displacement of membrane-associated particles upon aggregation of chromaffin granules.

Isolated chromaffin granules incubated in 10 millimolar calcium chloride aggregated, forming contact sites with a pentalaminar membrane structure. These circular attachment sites were free of membrane-associated particles, which accumulated at the periphery. Incubation in 20 millimolar ethylenediaminetetraacetic acid reversed these changes, which are regarded as initial events in the membrane fusion reaction.

Adrenal Medulla↗
PubMed1977

Correlation of physical and morphological parameters with release of catecholamines, ATP, and protein from adrenal medulla chromaffin granules.

Exchanging 0.3 M sucrose for 0.3 M glycerol as the bathing medium for isolated bovine adrenal chromaffin granules at 0 degrees C or raising the temperature of granules suspended in 0.3 M sucrose to 37 degrees C causes the release of catecholamines, ATP and soluble protein stored in the granules. These treatments also reduce the turbidity (absorbance at a non-absorbing wavelength) of the same suspensions. The glycerol-induced release is shown by morphology and morphometry to be due to lysis of the granules. Advantage is taken of the difference in density of the intact granules and the granule ghosts to confirm this result by centrifugation of glycerol-incubated samples on continuous gradients of sucrose and metrizamide. Similar centrifugation experiments performed on the granules incubated in sucrose at 37 degrees C show that lysis also accounts for the fast phase of release of granule contents, and not graded selective release of material from otherwise intact granules.

Adenosine Triphosphate↗
PubMed1977

An osmometer model for changes in the buoyant density of chromaffin granules.

We present a model for the structure of isolated bovine adrenal medulla chromaffin granules derived from the dependence of granule density on the osmotic pressure of the suspension medium at 2 degrees C. The granule consists of a flexible, inelastic membrane bounding an osmotically active core. The core consists of a solution space and a separate, nonosmotic phase. Since the granule behaves like a "perfect" osmometer over a wide range of osmolarities, we conclude that (a) within these limits, the core consists of a constant amount of condensed material and a constant number of particles in solution, (b) from the constraints of the osmometer model, the osmolality inside the granule must equal the osmolality outside. Therefore the high concentrations of catecholamines (greater than 0.7 M) and ATP (greater than 0.18 M) measured biochemically cannot be dissolved in the core solution as separate molecules, but must be condensed into larger aggregates. These results are supported by electron micrographic examination of the effect of osmotic pressure changes on granule morphology.

Adenosine Triphosphate↗
PubMed1977

Sarcoidosis of the pineal gland. Case report.

The authors report a case of sarcoidosis of the pineal gland with no other organ manifestation of the disease. The tumor was successfully removed by a direct surgical approach.

Adolescent↗
PubMed1975

Idiopathic orthostatic hypotension. Biochemical and pathologic observations in 2 cases.

Two cases of idiopathic orthostatic hypotension are reported, one associated with striato-nigral degeneration (case 1) and the other with Lewy body parkinsonism (case 2). In case 1, cerebrospinal fluid monoamine studies were carried out before and during treatment with 5-HTP and L-dopa. Low values of 5-HIAA appeared to be associated with degeneration of the spinal cord intermediolateral column. L-dopa had a beneficial effect on both parkinsonism and hypotension over a period of 6 months. New pathologic observations included changes in the sacral cord and a topographically related involvement of the substantia nigra and striatum, consistent with recent experimental neuroanatomical data.

5-Hydroxytryptophan↗
PubMed1975

Fine structure and origin of amyloid deposits in pituitary adenoma.

A pituitary adenoma with amyloid deposits was studied by light and electron microscopy. The amyloid material was radially oriented, deposited in the extracellular space, and often intermingled with small vesicles. It was surrounded by histiocytes with deep cytoplasmic invaginations. The histiocytes contained large autophagic vacuoles in which amyloid was also present. These features are similar to other forms of amyloidosis and suggest a histiocytic origin of the amyloid.

Adenoma, Chromophobe↗
PubMedDate not supplied

Correlation of neuropathologic findings and phase-based MRI temperature maps in experimental laser-induced interstitial thermotherapy.

To investigate the correlation between the neuropathologic findings after laser-induced interstitial thermotherapy (LITT) and MRI temperature maps during laser irradiation, a total of six pig brains from cadavers were treated with a Nd:YAG laser (lambda = 1,064 nm, 3.8 W) for 15 minutes. For MRI monitoring, we used a phase-sensitive two-dimensional (2D) fast low-angle shot (FLASH) sequence on a 1.5-T Magnetom SP. Temperature maps were acquired every minute (accuracy, <1.5 degrees C). Histopathologic methods were selected (hematoxylin and eosin stain, Masson's trichrome, Bodian silver impregnation) to demonstrate the zonal architecture of LITT lesions in ex vivo specimens. They showed extensive destruction of the nervous tissue constituents, vascular changes, and lysis of erythrocytes near the track of the laser, a transitional zone, and an 1.5-mm broad margin with edema-like perinuclear vacuolization. No immunoreactivity of glial fibrillary acidic protein (GFAP) could be visualized inside the lesion. In a semiquantitative evaluation, the lesion sizes were measured microscopically (mean diameter = 12.8 mm) and their margins could be defined at temperature zones of 60 to 65 degrees C on the MRI maps.

Animals↗
PubMedDate not supplied

Barriers to help-seeking for change in drinking: a gender-focused review of the literature.

Women with drinking problems are less likely than men to utilize alcohol-specific treatment services; they are comparatively more likely to seek help in general health and mental health care settings. These patterns in service utilization may be attributable, in part, to gender differences in barriers or disincentives to seeking and receiving care for alcohol abuse. In this paper we provide a gender-focused review of research on barriers to help-seeking for addictions behavior change. Two major categories of barrier, involving client and treatment program characteristics, appear to have a greater impact on service utilization of women than men. Insights gained from barriers literature provide valuable direction for future research and suggest applications in clinical service provision and treatment planning.

Alcohol Drinking↗
PubMedDate not supplied

Progression of neurofibrillary changes and PHF-tau in end-stage Alzheimer's disease is different from plaque and cortical microglial pathology.

In terminal Alzheimer's disease (AD) the frequency of plaques was found to be reduced in single cases. To test this finding in a larger sample, and in order to determine whether the number of plaques labeled with different markers and the distribution of neurofibrillary tangles are correlated positively to each other and to the degree of dementia, a sample of 134 autopsy brains with and 15 without AD-related pathology has been examined. All of the cases were staged according to Braak and Braak. Both the frequency of plaques immunopositive for beta-amyloid, amyloid precursor protein, and apolipoprotein E and that of microglial cells in the cortex and in the white matter were determined semiquantitatively. The content and distribution of PHF-tau was ascertained by ELISA and immunohistochemistry. Both the clinical dementia rating and the global deterioration scale were used as clinical parameters retrospectively. Correlation coefficients were calculated for all parameters and differences were evaluated statistically. With progressive distribution of neurofibrillary tangles and increasing content of PHF-tau the plaque stages and the degree of cortical microglia reaction increased up to the Braak-stages IV and V, thereafter showing a slightly decreasing tendency in the investigated regions. In end-stage AD resorption of beta-amyloid seems to surpass its deposition. The microglial reaction in the white matter correlated neither with the Braak-stage nor with the accumulation of amyloid. With regard to the degree of dementia, both scales correlated well with the pathological changes. Our data show that neuronal cytoskeletal alterations progressively increase with progressive dementia until the end stage of AD in contrast to the frequencies of plaques and cortical microglial cells, and are therefore preferable for staging purposes.

Aged↗