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Biomedical subjects

B Winistörfer

Publications and source records attributed to B Winistörfer.

At least 19 recordsLinked to original sources
PubMed1994

Mid-term results with cultured epidermal autografts, allogenic skin transplants and cyclosporin A medication.

Transplantation of allogenic split thickness skin grafts (STSG) and immunosuppression with cyclosporin A enable early and definitive skin replacement of extensive, deep partial and full thickness burns. Covering burn defects with definitely engrafted, allogenic dermis and cultivated epithelial autografts (CEA) permits the subsequent withdrawal of cyclosporin A medication. Light-microscopy examination of biopsies, taken 12 and 24 months postgrafting, and electron microscopy of biopsies taken 12 months postgrafting, demonstrates a re-established, but somewhat reduced anchoring of the CEA as compared with a normal epidermal-dermal junction. Clinical inspection, 20 months postgrafting, confirms the histological observations that epifascial transplantation is qualitatively inferior to placing the allogenic STSG on the subcutaneous tissue. In the first situation, the dermis is inelastic and collagen deposition is excessive, whereas in the second case collagen deposition is comparatively reduced and the dermis shows clinically some elasticity.

Adult↗
PubMed1993

[Preservation of hepatocytes of the rat by active transport of glycine].

The measurement of the active accumulation of specific substrates against a concentration gradient in tissue fragments in vitro has proved to be a simple but excellent procedure to ascertain the viability of several cell types and, in parallel with routine microscopy, has become a reliable tool in assaying the biochemical and functional modifications of a tissue under physiopathological conditions. It also has the added advantage of using tissues that are not pretreated in any way such as the preparative procedures used in cell isolation methods. The majority of investigations employing hepatocytes has been carried out in material derived from cell cultures or on isolated cells in suspension. The aim of this study was to determine if active transport could be determined in whole-tissue fragments of livers. Following identification of the specific substrate system and ideal incubation conditions, this method was then used to test the validity of different organ preservation solutions after cold storage in vitro. Livers were rapidly removed from rats and incubated for 1 hour at 37 degrees C in oxygenated Krebs bicarbonate buffer containing the substrates in question marked with a tracer dose of 14C. Preliminary investigations showed that active transport by rat hepatocytes was non-existent for beta-methyl-glucoside, phenylalanine and AIB; low for arginine but very important for glycine and serine and that this uptake could be significantly abolished by the presence of choline in the incubation medium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[Value of antral mucosectomy, selective proximal vagotomy and a combination of the 2 procedures in serum gastrin production and inhibition of stomach acid. An experimental study].

This experimental study was aimed at determining the volume and acidity produced by the normal stomach, following antral mucosectomy (MA), proximal selective vagotomy (VSP) and combination of both procedures. In 10 mongrel dogs, a double-lumen tube was placed in the stomach under general anesthesia. One of the lumen was rinsed with a constant flow and the other retrieved the gastric secretion. Gastric secretion and acidity were calculated every 10 minutes for 120 minutes. At 60 minutes, pentagastrin was injected. After these controls, a MA was carried out in half the animals and a VSP in the other half. 6 and 12 weeks postoperatively, the same controls were repeated. The dogs were then submitted to the operation of the other group. Following MA and pentagastrin stimulation, the gastric secretion (volume) is not modified with regard to the preoperative levels. On the other hand, after VSP, pentagastrin stimulation induces only a small volume response. The vagus thus seems to be involved in liquid secretion of the stomach. Following MA, pentagastrin stimulation lowers gastric pH at 6 weeks but not at 12 weeks postoperatively. Gastrin is known to have a trophic effect on the oxyntic mucosa. This effect disappears in a few weeks and explains these different figures. Following VSP, gastric acidity decreases and plasmatic gastrin increases. In this situation, pentagastrin directly acts on a trophic mucosa and produces the important lowering of the gastric pH. Finally, after MA, pentagastrin induces an increase in plasmatic gastrin. This effect seems to be mediated by central stimulation of the nuclei of the vagus nerve.

Animals↗
PubMed1992

Alanine uptake by the endothelium of canine blood vessels and by the vessels of human umbilical cord.

In order to determine whether the endothelium of vascular wall fragments possesses an active uptake mechanism for alanine identical to the one present in endothelial cells in tissue culture samples of canine aorta, carotid artery and vena cava, human umbilical cord vessels, were incubated in vitro in the presence of labelled alanine. In a series of experiments, it was observed that all the tissues investigated accumulated a significant amount of this substrate against a concentration gradient, and that the accumulation was saturable in the presence of sodium. This uptake was sodium-dependent, was significantly inhibited by ouabain and was greatly reduced under anoxic conditions. Finally, the uptake was completely abolished by prior mechanical or osmotic destruction of the intima. In conclusion, the very reproducible measurement of active alanine uptake in fragments of blood vessels may be a valuable method of evaluating the integrity of the endothelium.

Alanine↗
PubMed1992

[Origin of secretions after denervation of the small intestine in the dog].

The origin of the severe diarrhea appearing after intestinal denervation or transplantation was studied on the 3rd and 14th postoperative days in 5 groups of dogs undergoing total or partial denervation. The net movements of water and electrolytes were investigated by employing an experimental model of intestinal perfusion in isolated loops in vivo. The active uptake of phenylalanine and beta-methylglucoside and Na(+)-K(+)-ATPase activity were used for in-vitro evaluation. Bacteriologic and histological specimens were also taken. Following total denervation with anastomosis, a considerable loss of water and electrolytes as well as numerous E. coli were found in the entire small intestine. This net secretion is due to the stagnation of bacteria in the presence of complete denervation and the absence of food since the animals in this group could not eat properly following general anesthesia and surgery. Consequently, peristalsis was not stimulated and bacterial overgrowth occurred. In the group denervation with pseudo-anastomosis, perfusion studies showed a decrease of absorption in the jejunum and minimal but significant secretion in the ileum. A high number of E. coli was also present. Since the mucosa remained intact, nutrition per os was resumed in the immediate postoperative period and excessive water and electrolyte loss was avoided. The high number of bacteria was due to a decrease in intestinal motility since complete denervation was performed. In the denervation group, water and electrolyte movements were identical to those observed in the preceding group but the entire intestine remained sterile.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Development of a gastroplasty with variable diameter. Experimental study using artificial sphincters].

The vertical banded gastroplasty is currently the most popular technique in the surgical treatment of morbid obesity. This experimental study was aimed to create a gastroplasty with a variable stoma. The Marlex band was replaced by the cuff of an artificial sphincter to allow selective variation of the diameter of the stoma. The study was carried out on four mongrel dogs. The artificial sphincter was connected to a subcutaneous port. Injection of sterile fluid into the port inflates the cuff and decreases the surface of the stoma. The study was followed up for one year. Under gastroscopic control the system was regularly activated, the diameter and the surface of the stoma was measured and calculated. The sphincter allowed the surface of the stoma to decrease from 103 +/- 2.0 mm2 to 61 +/- 2.1 mm2. There was no significant variation of the surface for each volume unit injected into the system. After one year, the systems and stomachs were harvested and examined. It is possible to create a gastroplasty with a variable stoma. This system works without any technical problem. Microscopic examination of the stoma shows no peri-sphincteric fibrosis.

Animals↗
PubMed1992

[An evaluation method for organ preservation].

The determination of the active transport of alanine by canine endothelial cells was employed as a parameter to test cellular viability following conservation in vitro at 4 degrees C in Krebs bicarbonate buffer (KB), St. Thomas (ST), Euro-Collins (EC) or University of Wisconsin (UW) solutions. Following 24-hour conservation, active transport values demonstrated that the highest results were obtained with UW solution. At the same time, dog renal cortex slices were also tested under identical conditions and, once again, UW solution proved to be the best. Conservation was then extended to 72 hours and UW solution still afforded maximum protection of cellular viability.

Alanine↗
PubMed1989

Recombinant human interleukin-1 beta decreases serum carboxypeptidase N and modifies serum amino acid concentrations in rats.

The effects of recombinant human interleukin-1 beta (rhIL-1 beta) on various serum constituents were studied following subcutaneous injection (12.5 or 125 micrograms/kg) in female Wistar rats. Protein electrophoresis and the determination of the serum concentrations of carboxypeptidase N (CPN), aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, aldolase, total proteins, iron, urea, creatinine, and several amino acids were performed 12, 24, and 72 hr after injection. With both doses of rhIL-1 beta, iron, albumin, CPN, and lysine were significantly decreased whereas alpha 2-globulin, urea, and creatinine were significantly increased 12 hr after administration. Iron and CPN were still low after 24 hr but returned to normal levels after 72 hr. With the higher dose of rhIL-1 beta, only alanine and phenylalanine levels were increased after 12 and 72 hr, taurine after 12 hr, and methionine after 24 hr. There were no biochemical or histological signs of hepatotoxicity. The findings indicate that rhIL-1 beta produces a reversible alteration of various biochemical plasma constituents without any apparent signs of cytotoxicity. Moreover, the decrease in CPN observed may influence the degradation of inflammatory peptides.

Amino Acids↗
PubMed1989

Active uptake of amino acids by the urinary bladder epithelium of rat, rabbit, and dog.

Through a series of experiments employing tissue fragments incubated in vitro together with labeled substrates, it was observed that the tight urinary bladder epithelia of rat, rabbit, and dog possess the capacity of an active accumulation of amino acids against a concentration gradient. This uptake is saturable in the presence of sodium, is sodium-dependent, and is inhibited by ouabain. In comparison with other tissues, this phenomenon of active uptake is strikingly resistant to anoxia. The direction of uptake is from blood to lumen across the basolateral epithelial membrane. The induction of hyperplasia in the bladder epithelium of dogs very significantly increased the uptake of amino acids. Further studies should confirm the presence of this phenomenon in the human bladder.

Amino Acids↗
PubMed1987

Effect of dimethyl sulfoxide on the function and structure of the intact and ischemic canine ileum.

The action of dimethyl sulfoxide (DMSO) was investigated employing an experimental model of intestinal perfusion in vivo of isolated loops of dog ileum before, during, and following 1-h ischemia. DMSO was administered either into the intestinal lumen or by a continuous injection via a branch of the artery supplying the experimental loop. In the intact intestine, intraluminal DMSO significantly decreased the net movement of water, electrolytes, and glucose without affecting either the active transport of phenylalanine and beta-methylglucoside or morphology. This inhibition was irreversible since, following DMSO removal, there was only partial recovery of water absorption, while the other parameters remained significantly low. Inhibition by DMSO was delayed when the substance was injected intraarterially (i.a.). Regardless of its route of administration, DMSO did not reduce the extent of ischemic injury in comparison with non-treated "Controls": during ischemia, all functional parameters were practically non-existent. Following the re-establishment of circulation, a net loss of water and electrolytes ensued, and active transport did not improve. In both instances, the structural alterations were those associated with ischemia of the experimental model employed: short, broad, club-shaped villi which had completely lost their epithelium, but fairly intact crypts. It can be concluded from the data presented that in the dog DMSO inhibits absorption in the intact ileum and exerts no protection against ischemic lesion.

Animals↗
PubMed1982

Functional alterations in the dog colon mucosa following temporary ischaemia.

Segments of dog colon were subjected to 1 h of total ischaemia. In one experimental group, the colon was not touched before the trauma; in another, it was rinsed out before the intervention; while in a third, it was perfused with Krebs bicarbonate buffer during injury. In all groups, the mucosa after the trauma is the site of net movement of water, sodium and chloride towards the lumen, while glucose absorption is greatly reduced. The accumulation of amino acid and sugar in vitro by samples of ischaemic mucosa is reduced but not abolished. The capacity for organic solute transport in vitro is greater in samples removed after the perfusion than in specimens excised immediately after the end of the ischaemia. According to the test in vitro, the mucosa can be protected from the deleterious effects of the ischaemia by intraluminal perfusion during the ischaemia. Immediately after 1 h of ischaemia, slight alterations in the histological structure of some villi were observed under the light microscope in occasional animals, particularly when the colon was not rinsed out before the ischaemia.

Animals↗