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Biomedical subjects

R Schaller

Publications and source records attributed to R Schaller.

16 recordsLinked to original sources
PubMed1999

Abnormal growth and clonal proliferation of fibroblasts in an animal model of unilateral ureteral obstruction.

The time course for the development of renal interstitial fibrosis (RIF) in rats between days 5 and 25 after unilateral ureteral obstruction (UUO) was studied. In kidneys with UUO under histological examination, an interstitial fibrosis was observed after more than 10 days with progression up to day 25. On day 5, collagen peptidase activity in homogenates of UUO kidneys was about 50% higher than in controls but gradually declined afterwards until reaching the level obtained from contralateral kidneys (CL) on day 25. 10 days after UUO, renal hydroxyproline content was elevated about twofold as compared to CL and sham-operated rats, and increased considerably by day 25 of UUO. In primary cultures of cells obtained from UUO kidneys, fibroblast proliferation increased regardless of the extent of fibrosis. This could be a result of an early inflammatory process. Renal fibroblasts from rats are heterogenous when studied in vitro. When fibroblasts of passage 1 obtained from kidneys 25 days after UUO were plated at low density, the number of mitotic type I clones was elevated 5.5-fold as compared with cultures from CL kidneys. The majority of type I clones in UUO cultures from fibrotic kidneys developed in an unusual fashion with formation of three-dimensional structures. The changes detectable under the unfavorable conditions of clonal culture suggest phenotypical differentiation of a small fraction of fibroblasts from kidneys with RIF. These cells are able to overgrow cell monolayers forming circular growing colonies. Obviously, one needs to distinguish between intensive proliferation as a consequence of acute inflammation, and the changes in phenotype of a small fraction of renal fibroblasts which are resistant to normal physiologic regulative mechanisms in cell culture. The latter may contribute to matrix disorders and RIF.

Animals↗
PubMed1998

Percutaneous placement of ventriculoatrial shunts in the pediatric population.

The percutaneous placement of ventriculoatrial (VA) shunts has been previously described, usually in adults. We report a series of 7 pediatric cases ranging from 6 to 17 years. Five patients were female and 2 were male. All patients had prior ventriculoperitoneal (VP) shunts for hydrocephalus, of which 1 had been subsequently converted to a ventriculopleural shunt. Indications for conversion to a VA shunt were intra-abdominal infection in 6 cases and chronic pleuritic chest pain in 1 patient. The venous entry was the subclavian vein in all cases. All patients have remained asymptomatic since the operation. There were no complications associated with the procedures, with follow-up ranging from 2 to 12 months. This technique is a viable alternative to the open cervical approach for venous entry to the right atrium in the pediatric population.

Adolescent↗
PubMed1997

Morphofunctional effects of moderate forebrain ischemia combined with short-term hypoxia in rats--protective effects of Cerebrolysin.

Morphofunctional effects of combined moderate forebrain ischemia due to permanent bilateral carotid artery ligation and short-term systemic hypoxia in rats were investigated. Moreover, a putative effect of brain protection by Cerebrolysin (Cerebrolysin, EBEWE, Austria), a brain tissue hydrolysate containing a mixture of 85% free amino acids and 15% small peptides (MW < 10,000), was studied. Eighty-seven adult Wistar rats (24 Cerebrolysin treated and 63 controls) were subjected to chronic moderate forebrain ischemia by permanent bilateral carotid artery ligation for 7 days. Twenty-four hours after the onset of ischemia, 56 of them underwent an additional hypoxic hypoxia (FiO2 = 0.08) of 15 min. A first group (19 out of 56 animals) received Cerebrolysin (every dose 2.5 ml/kg body weight s.c.) after ligation, after hypoxia and then daily. A second group (6 out of 56 animals) received an equal volume of physiological saline after ligation and Cerebrolysin the first time after hypoxia and then once a day. An untreated control group (31 out 56 animals) received physiological saline. Changes in behavior were scored and electrophysiological activity was quantified by spectral ECoG analysis before carotid artery ligation, before and after hypoxia, and once a day during the following 7 days. On the 7th day after hypoxia, the animals were sacrificed and the grade of histological damage was quantified by morphometry. After permanent carotid artery ligation, 20 out of 63 (31.7%) untreated control animals died within 24 h but only 4 out of 20 (16.7%) Cerebrolysin treated animals. However, Cerebrolysin had not detectable effect on mortality after the additional acute hypoxia. Within 24 h after hypoxia, ECoG power of the higher frequency ranges remained low (p < 0.05). Surviving animals showed a significantly higher ECoG power during and 15 min after hypoxia than those animals that died within 48 h after hypoxia (p < 0.05). All animals showed reduced behavioral activity (p < 0.01) 20 min after hypoxia, however, basal reflex responses were not altered. The major patterns of neuronal damage were coagulation necrosis and general sponginess of the neuropil which is a sign of brain edema. These changes occurred predominantly within the superolateral convexities of the parietal cortex, in the entorhinal and in the piriform cortex as well as in the CA1 and CA4 region and in the dentate gyrus of the hippocampus. The striatum and the origin nuclei of the brain nerves were also affected. We did not observe a relationship between behavior, ECoG depression and the extent of morphological damage after hypoxia nor did we find any protective effects of Cerebrolysin on these parameters. Rather it is suggested that the degree of ECoG depression immediately after hypoxic hypoxia could be a predictor for prognosis of animal survival. Cerebrolysin reduced the amount of early mortality which was caused by moderate global forebrain ischemia. However, no protective influences of the amount of brain tissue damage could be shown.

Amino Acids↗
PubMed1994

Limited surgery for lower-segment Hirschsprung's disease.

OBJECTIVE: To determine if rectal myectomy is an effective treatment for a specific group of patients with Hirschsprung's disease. DESIGN: Retrospective series with follow-up of 6 to 132 months (mean follow-up, 37.1 months). SETTING: Children's hospital. PATIENTS: Fourteen children aged 2 to 14 years with chronic constipation and nondiagnostic barium enema contrast study findings. INTERVENTION: Posterior rectal myectomy. MAIN OUTCOME MEASURES: Laxative use, frequency of stools, incidence of soiling or incontinence, and patient's assessment of improvement. RESULTS: The conditions of all 14 patients improved regardless of the presence of ganglion cells in the myectomy specimen; there were six excellent, six good, and two fair assessments. laxatives were used intermittently by seven of 14 patients. No patients complained of incontinence or soiling. CONCLUSIONS: Rectal myectomy is an effective, less-extensive operation that should be considered for older children with Hirschsprung's disease.

Adolescent↗
PubMed1994

Differences in intravenous and subcutaneous application of recombinant human erythropoietin: a multicenter trial.

The aims of this clinical study were to compare the maintenance doses for intravenous (i.v.) and subcutaneous (SC) administration of recombinant human erythropoietin (rhEPO) and to investigate whether there is any difference in the increase of the packed cellular volume (PCV) per week under i.v. and SC administration of rhEPO from two production sites (Genetics Institute, Cambridge, USA; and Boehringer Mannheim, Penzberg, Germany). A total of 90 patients suffering from end-stage renal disease were included in the study. All patients had already been treated for at least 6 months with chronic hemodialysis. The study was carried out as a randomized, multicenter parallel group comparison study with a 1-week pretreatment phase, a subsequent 8-week double-blind phase, and a final open phase. The final open phase consisted of a correction phase and a maintenance phase. The production site had no influence on the PCV increase per week, and there were no differences with respect to tolerability. The median rhEPO dose required to maintain the target PCV of 30 to 35 vol.% was 33 U/kg body weight three times a week in the i.v. group compared with 22 U/kg in the SC group (i.e., an average of 30% less with SC administration). Development or aggravation of hypertension under rhEPO therapy was observed, especially during the correction phase and more frequently in the SC group than in the i.v. group. During the maintenance phase, there was no essential difference between the two groups.

Adult↗
PubMed1993

Clinical evaluation of a new dialyzer, FLX-12 GW, with a polyester-polymer alloy membrane.

The performance of a membrane in renal failure therapy is determined by its structure, its overall mass transfer properties, and its blood compatibility. In this regard, removal of beta 2-microglobulin (beta 2M) has become a major objective of dialysis therapy. In the present study, a newly developed high-flux membrane composed of a polyester-polymer alloy (PEPA) with the components of polyarylate and polyethersulfone (dialyzer FLX-12 GW; Nikkiso Co., Japan) has been evaluated with regard to both biocompatibility and elimination capacity for beta 2M during hemodialysis of 8 stable chronic uremic patients. The clearance values of low molecular weight solutes were in the same range as those reported for high-flux dialyzers of comparable surface area. There was no drop in leukocyte counts and only a minimal fall in platelet counts nearly in the same range as has been observed by other investigators using polyamide membrane. C3a Des Arg generation was low, and C5a Des Arg formation was not significantly influenced. There was a sharp drop in the serum beta 2M level (-35%) during dialysis with a clearance between 59.7 +/- 5.6 ml/min (QB 200 ml/min) and 70.1 +/- 9.7 ml/min (QB 300 ml/min), respectively. Accordingly, the sieving coefficient was calculated to be 0.2 at 30 min after start of dialysis and 0.6 1 h later. The membrane was able to remove 184.0 +/- 22.3 mg/4 h due to an apparent rate of adsorption during the first hour of treatment in combination with high transmembrane transfer in the following time.

Adult↗
PubMed1992

Foreign bodies within a Meckel's diverticulum.

Although complications of Meckel's diverticula are relatively common, there has not been a reported case, to our knowledge, of foreign bodies impacted within a Meckel's diverticulum. We report herein a case of a 2-year-old child who had two pennies trapped in a Meckel's diverticulum. This case demonstrates that foreign objects in the right lower quadrant that do not progress may be impacted in a Meckel's diverticulum.

Acute Disease↗
PubMed1992

Gastroschisis wringer clamp: a safe, simplified method for delayed primary closure.

When primary abdominal wall closure in a newborn with gastroschisis cannot be accomplished safely, placement of a reinforced Silastic silo facilitates delayed primary closure (DPC). In this report we describe our experience with the gastroschisis wringer clamp (GWC). The GWC is an autoclavable, 140-g, aluminum alloy device reminiscent of an old wringer washing machine. It consists of two apposing serrated rollers that pull the Silastic silo through a slotted base plate. This protects the intestine and converts the circular defect into a vertical slit to ease DPC. The GWC is adjusted daily on the awake newborn in the nursery and the magnitude of each adjustment is gauged by the infant's cardiac and pulmonary status. For the past 10 years we have cared for 116 newborns with gastroschisis. The average birth weight was 2,530 g (range, 1,380 to 3,300 g). Eighty-six infants (74.1%) have undergone primary closure. The remaining 30 infants (25.9%) were treated by placement of a Silastic silo and application of the GWC, forming the basis of this report. The DPC operation was performed an average of 6.7 days (range, 3 to 23 days) following the application of the silo. Extubation was usually possible prior to the DPC, with the mean length of mechanical ventilation being 3.8 days. Three patients developed serious complications including two dehiscences of the silo-fascia interface. There were no deaths in this group of 30 patients. The GWC offers many technical advantages and can be easily reversed when the infant's cardiopulmonary status deteriorates. We advocate its adoption as a method of choice in the newborn with gastroschisis who requires DPC.

Abdominal Muscles↗
PubMed1989

Effects of hypoxic hypoxia on the kinetics of synaptosomal Ca2+-ATPase activity in newborn piglets and young rabbits.

Severe hypoxic hypoxia with electrophysiologically detectable involvement of the brain caused a distinct alteration of synaptosomal membrane Ca2+ATPase activity in newborn piglets (n = 7) and young rabbits (n = 7). This was shown by means of the shifted pCa2+ for maximum stimulation towards higher Ca2+ concentrations and a significant decrease of the maximum activity in both species. Furthermore, an additional stimulation using supramaximum amount of exogeneous calmodulin (tested on piglets) was completely abolished after hypoxia. It is suggested that this effect might influence the fine regulation of neuronal Ca2+ homeostasis also during the posthypoxic recovery period.

Animals↗
PubMed1986

Diagnosis and treatment of splenic fungal abscesses in the immune-suppressed patient.

In an 18-month period candidal splenic abscesses were diagnosed and treated in eight patients. Predisposing factors consisted of recent exposure to cytotoxic chemotherapy, long-term use of prednisone, neutropenia, antibiotic therapy for greater than three weeks, and gastrointestinal tract colonization with Candida. The patients had a clinical profile of nontoxic appearance with a temperature of more than 38.5 degrees C that was unresponsive to antibiotics, pain and tenderness over the upper abdominal quadrants, focal defects visualized on ultrasound and/or computed tomographic scans, and an elevated alkaline phosphatase level. Candida infection was confirmed by histologic examination of the liver and/or spleen in all patients. Diagnosis was made by percutaneous biopsy in one patient and exploratory laparotomy in seven. Five patients had splenectomy and antifungal drugs. In three patients the fungal abscesses resolved with amphotericin B therapy alone. Seven of eight patients were cured of their splenic abscesses, and five of eight were long-term survivors.

Abscess↗
PubMed1979

Micromorphology of the skin (epidermis, dermis, subcutis) of the dog.

Grossly, the skin of the dog is characterized by varying thicknesses, density of the hair coat and the implantation angle of the hairs. Multiple folds varying in shape are formed by the epidermis and the papillary layer of the corium. The epidermis consists of a stratum profundum with a continuous layer of basal cells, a stratum spinosum consisting of 3-6 cell layers, a stratum superficiale with single granulosa and "lucidum" cells and a well-developed stratum corneum. The corium shows a narrow stratum papillare corli containing delicate fibres and a broad stratum reticulare corii with mainly coarse fibre bundles. The subcutis is divided into adipose and fibrous layers. The broad adipose layer displays breed and individual differences which vary with the region of the body. The fibrous layer corresponds to the connective tissue layer, formerly described as fascia trunci superficialis. The morphological and functional unity of the corium and subcutis is discussed.

Adipose Tissue↗