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Biomedical subjects

C Schwarz

Publications and source records attributed to C Schwarz.

At least 91 records · Page 5Linked to original sources
PubMed1995

Huntingtin is a cytoplasmic protein associated with vesicles in human and rat brain neurons.

The gene defective in Huntington's disease encodes a protein, huntingtin, with unknown function. Antisera generated against three separate regions of huntingtin identified a single high molecular weight protein of approximately 320 kDa on immunoblots of human neuroblastoma extracts. The same protein species was detected in human and rat cortex synaptosomes and in sucrose density gradients of vesicle-enriched fractions, where huntingtin immunoreactivity overlapped with the distribution of vesicle membrane proteins (SV2, transferrin receptor, and synaptophysin). Immunohistochemistry in human and rat brain revealed widespread cytoplasmic labeling of huntingtin within neurons, particularly cell bodies and dendrites, rather than the more selective pattern of axon terminal labeling characteristic of many vesicle-associated proteins. At the ultrastructural level, immunoreactivity in cortical neurons was detected in the matrix of the cytoplasm and around the membranes of the vesicles. The ubiquitous cytoplasmic distribution of huntingtin in neurons and its association with vesicles suggest that huntingtin may have a role in vesicle trafficking.

Animals↗
PubMed1995

Modular organization of the pontine nuclei: dendritic fields of identified pontine projection neurons in the rat respect the borders of cortical afferent fields.

Cortical afferents transferring information destined for the cerebellum terminate in the pontine nuclei (PN) in a divergent and patchy fashion. We investigated whether the form of dendritic fields of pontine projection neurons which are postsynaptic to the cortical afferents are related to this patchy pattern. To this end we used a triple combination of (1) retrograde labeling (injection of Fluorogold into the brachium pontis), (2) anterograde labeling [injection of Dil into cortical areas A17 and Sml(forelimb)], and (3) subsequent intracellular fills of identified projection neurons (Lucifer yellow) in slightly fixed slices of pontine brainstem. In 64 projection neurons whose somata were located within 160 microns of the border defined by cortical afferent fields, most of the dendritic trees were found to respect the border. Strikingly, proximal dendrites which were oriented toward the border often bent in order to avoid the boundary. This observation was supported by a quantitative analysis. It revealed that overlap areas of dendritic fields with the neighboring compartment were significantly smaller than those of hypothetical, radially organized dendritic fields of the same size, indicating that the dendritic fields are indeed confined to single compartments. In a second series of experiments, double injections of the anterograde tracers Dil and DiAsp into adjacent sites within one cortical area (A17 or Sml) were made in order to test if the topology of the cortical map is preserved within individual pontine compartments. This, however, does not seem to be the case, since the terminal fields displayed a complex pattern of overlap and nonoverlap rather than a consistent shift of terminal fields expected in the case of preserved topology. The results of the present study are consistent with the view that pontine modules independently process information from different parts of individual cortical areas. We suggest that this characteristic property of the corticopontine projection system might be the morphological basis of the well established fact that somatotopically continuous sensory maps in the cortex are transformed into maps at the level of the cerebellar cortex, showing a fractured somatotopy.

Afferent Pathways↗
PubMed1995

[Diagnosis and and differentiation of dry eye disorders].

Artificial tears often fail in dry eye patients. Our goal was to establish a diagnostic approach that involves alternatives that are more effective for the treatment. We examined 110 patients with dry eyes not stabilized by artificial tears: medical history, visual acuity, slit lamp examination, rose bengal stains and fluorescein stains, Schirmer test, break-up time (BUT), dye tests, impression cytology, and lid transillumination. This allowed disturbances of the three layers of the tear film (lipid, aqueous, mucin) to be differentiated. Cellular damage of the ocular surface was evaluated and scored by slit lamp examination, rose bengal staining, and impression cytology. Only 8% of the patients with "sicca syndrome" had exclusive aqueous deficiencies amenable to artificial tears. In contrast, lipid deficiencies (chronic blepharitis) were determined most frequently (78%). Twenty-six percent had disturbances in two or more layers of the tear film. The diagnostic strategy of differentiating disturbances of the layers of the tear film offers a more specific approach to the treatment of dry eyes.

Adult↗
PubMed1994

Sodium-taurocholate-induced acute necrotizing pancreatitis does not affect jejunal oxygenation in pigs.

OBJECTIVE: To study the influence of experimentally induced acute necrotizing pancreatitis on jejunal oxygen transport, jejunal oxygen consumption, and mucosal PO2. DESIGN: Prospective, randomized trial. SETTING: Animal laboratory. SUBJECTS: Domestic pigs aged 7 to 8 wks. INTERVENTIONS: Two groups of pigs were anesthetized with midazolam and sufentanyl, mechanically ventilated, and hemodynamically monitored. In controls (n = 9) and in animals with acute necrotizing pancreatitis (n = 9), a segment of the jejunum was isolated and autoperfused in situ. Through an antimesenteric enterotomy, an area of jejunal mucosa was exposed for mucosal PO2 measurements. Acute necrotizing pancreatitis was induced by the injection of 10 mL of 10% sodium-taurocholate into the main pancreatic duct. Both groups received normal saline solution to keep pulmonary artery occlusion pressure constant. MEASUREMENTS: Mucosal PO2 was assessed with a modified Clark-type multiwire surface electrode. After two baseline measurements, systemic and regional oxygen transport variables and mucosal PO2 were determined at designated intervals (20, 40, 60, 100, 120, 160, 200, 240, 280 mins). MAIN RESULTS: Systemic hemodynamics and oxygen transport were maintained in both groups. In contrast to controls, all animals with pancreatitis showed gross macroscopic and histologic evidence of severe acute necrotizing pancreatitis at autopsy. There were no significant differences between groups in jejunal blood flow, oxygen transport, oxygen consumption, oxygen extraction ratio, or mucosal PO2. CONCLUSIONS: Our results demonstrate that, under conditions of sustained systemic hemodynamics, jejunal oxygen transport and mucosal oxygenation are well maintained during the early course of sodium-taurocholate-induced acute necrotizing pancreatitis.

Acute Disease↗
PubMed1994

Localization of proliferating cell nuclear antigen, vimentin, c-Fos, and clusterin in the postischemic kidney. Evidence for a heterogenous genetic response among nephron segments, and a large pool of mitotically active and dedifferentiated cells.

The mechanisms leading to the recovery of the kidney after ischemic acute renal failure are poorly understood. To explore the role played by mitogenesis and dedifferentiation in this repair process and to identify whether the genetic response of the nephron segments reflects the level of susceptibility to injury, the temporal and nephron segment expressions of various proteins implicated in mitogenesis, differentiation, and injury were determined. Proliferating cell nuclear antigen (PCNA), a marker for the G1-S transition in the cell cycle and hence mitogenesis, was detected primarily in the S3 segment of the proximal tubule, with maximal expression at 2 d postischemia. Vimentin, normally present in mesenchymal cells but not epithelial cells, and hence a marker for the state of differentiation, was prominently expressed in the S3 segment 2-5 d postischemia. In the S3 segments in the outer stripe of the medulla cells that stained positively for PCNA also stained positively for vimentin. Clusterin, a marker for cell injury, was expressed primarily in the S3 segment and in the distal tubule with distinct staining patterns in each segment. None of the cells that stained with clusterin antibodies were positively stained with PCNA or vimentin antibodies. Likewise, none of the PCNA or vimentin-positive cells expressed clusterin at detectable levels. Thus, in the S3 segment, where there is significant ischemic injury, surviving cells express markers indicating that they undergo mitogenesis and dedifferentiate in the postischemic period. While there is some expression of c-Fos in the S3 segment, c-Fos was expressed predominantly, at 1 and 3 h postischemia, in the nuclei of the distal nephron, particularly in the thick ascending limb. The data support the view that the mature renal S3 segment epithelial cell can be a progenitor cell.

Animals↗
PubMed1993

[Stent implantation in solitary aneurysm of the common iliac artery].

A 56-year-old man had intermittent claudication in the right leg for 11 months, gradually worsening of late. Digital subtraction angiography demonstrated an aneurysm, 8 x 2.5 cm, of the right common iliac artery and 70% stenosis of the right external iliac artery. As the patient refused full surgical intervention the aneurysm was treated by the insertion of two exactly adjoining wall stents (diameter 9 mm, length 7 cm), and the arterial stenosis was balloon-dilated. One month after stent implantation the aneurysm had thrombosed outside of the stent and the stent lumen was being perfused normally. 6 months later the local findings were identically. The patient remained symptom-free. --The case illustrates that management of circumscribed aneurysms by stent implantation could well be an alternative to surgical treatment, as long as the stent can prevent enlargement and rupture of the aneurysm.

Aneurysm↗
PubMed1992

[Are prism glasses a sensible measure in treatment of dyslexia?].

A short summary of the characteristics of speaking, reading and writing is given, followed by the respective anatomical, physiological and neuropsychological counterparts, which are to be described as the "Hör-Denk-Sprech-Seh-Schreib-Organismus" (H-D-S-S-SCH-O). Various disorders occurring in the H-D-S-S-SCH-O as well as health problems and psychological and/or sociological factors may negatively contribute to the ability of speaking, reading and writing. In each case medical and non-medical specialists should thoroughly assess the cause of the problem in order to select the most effective treatment method. An agreement was made between Dr. Pestalozzi (Olten) and the author, to asses logopedically from 1987 until 1990 at the Speech Therapy Clinic (Abteilung Klinische Logopädie, ORL-Klinik, Universitätsspital Zürich) 20 dyslexic children, aged 7 to 13 years, designated by Dr. Pestalozzi to the wearing of prism-glasses in order to cure their dyslexias. The results of this logopedic study are described and discussed.

Child↗
PubMed1992

Endosonography (ES) in the diagnosis of recurrent cancer of the rectum.

The ability of endosonography (ES) to detect local recurrence after "curative" surgery for rectal cancer was investigated in 65 patients. Fifteen patients developed local recurrence. All of these 15 patients had ES evidence of recurrence; in four cases recurrence was detected by ES alone. Ten of the 15 patients with local failure underwent reoperation. Four patients were candidates for reoperation for cure. Three patients with radical reoperation belonged to the group in which recurrence was detected by ES alone. ES is able to detect small tumors before there is evidence of recurrence in other available forms of examination.

Adult↗