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Biomedical subjects

M Wendt

Publications and source records attributed to M Wendt.

At least 73 records · Page 4Linked to original sources
PubMed1997

Cerulein-induced acute pancreatitis in rats--does bacterial translocation occur via a transperitoneal pathway?

Bacterial infectious complications are the most common cause of morbidity and mortality associated with acute pancreatitis. Most pathogens are common gastrointestinal flora, indicating that the gut is the source of pancreatitis-related infections. However, the route whereby the microorganisms reach distant organs remains speculative. We tested the hypothesis that spread of bacteria occurs via a transperitoneal pathway. Acute interstitial pancreatitis (AIP) was induced in antibiotic (gentamicin, bacithracin, neomycin)-decontaminated rats by intravenous infusion of cerulein. Effects of pancreatic necrosis (PN) were studied in rats that received additional injections into the peritoneal cavity of pancreatic tissue obtained from donor rats. The rats were inoculated with Escherichia coli (O2:KN:H18) resistant to the antibiotics used for decontamination either orally (10(12) microorganisms; experiment I) or intraperitoneally (10(8) microorganisms; experiment II). Moreover, the rat peritoneal cavity wash was inoculated with 10(8) E. coli in vitro (experiment III). In rats with AIP and PN, recovery of the bacteria from liver, spleen, pancreas, lung, and blood following oral inoculation demonstrated that acute pancreatitis promotes bacterial translocation from the gut. The absence of E. coli in these organs following intraperitoneal inoculation showed that the bacteria do not spread from the peritoneal cavity. Rats with PN cleared E. coli from the peritoneal cavity in a shorter period than rats with AIP and controls (5 vs. 7 and 8 days; p < 0.05). The multiplication rate of E. coli in peritoneal cavity wash was lower in rats with PN than in rats with AIP and controls (p < 0.01). We conclude that (1) translocation of E. coli from the gut during cerulein-induced acute pancreatitis occurs via nonperitoneal pathways, (2) the peritoneal cavity acts as a trap for the bacteria rather than a source of bacterial seeding, and (3) PN impairs survival of E. coli in the peritoneal cavity via inhibition of the bacterial multiplication in this model.

Acute Disease↗
PubMed1997

Effect of thoracic epidural anaesthesia on ventilation-perfusion distribution and intrathoracic blood volume before and after induction of general anaesthesia.

BACKGROUND: Gas exchange is impaired during general anaesthesia due to development of shunt and ventilation-perfusion mismatching. Thoracic epidural anaesthesia (TEA) may affect the mechanics of the respiratory system, intrathoracic blood volume and possibly ventilation-perfusion (VA/Q) distribution during general anaesthesia. METHODS: VA/Q relationships were analyzed in 24 patients undergoing major abdominal surgery. Intrapulmonary shunt (Qs/QT), perfusion of "low" VA/Q areas, ventilation of "high" VA/Q regions, dead space ventilation and mean distribution of ventilation and perfusion were calculated from the retention/excretion data of six inert gases. Intrathoracic blood volume (ITBV) and pulmonary blood volume (PBV) were determined with a double indicator technique. Recordings were made before and after administration of 8.5 +/- 1.5 ml bupivacaine 0.5% (n = 12) or 8.3 +/- 1.8 ml placebo (n = 12) into a thoracic epidural catheter and after induction of general anaesthesia. RESULTS: Before TEA, Qs/QT was normal in the bupivacaine group (2 +/- 2%) and the placebo group (2 +/- 3%). TEA covering the dermatomal segments T 12 to T 4 had no effect on VA/Q relationships, ITBV and PBV. After induction of general anaesthesia Qs/QT increased to 8 +/- 4% (bupivacaine group, P < 0.05 and to 7 +/- 2% (placebo group, P < 0.05). ITBV and PBV decreased significantly to the same extent in the bupivacaine group and the placebo group. CONCLUSIONS: TEA has no effect on VA/Q distribution, gas exchange and intrathoracic blood volume in the awake state and does not influence development of Qs/QT and VA/Q inequality after induction of general anaesthesia.

Anesthesia, Epidural↗
PubMed1997

Local delivery of platelets with encapsulated iloprost to balloon injured pig carotid arteries: effect on platelet deposition and neointima formation.

Local delivery of a drug to the arterial wall during angioplasty is an approach which might reduce the incidence of occlusive events such as thrombosis and restenosis, without the risk of systemic side effects. By exploiting their natural primary haemostatic properties, platelets, with encapsulated drugs, can be targeted to a vessel wall injury site and act as a depot for sustained release. The platelet plasma membrane can be reversibly permeabilised by high voltage, short duration electrical pulses (electroporation). Drugs will diffuse into porated platelets and become trapped on resealing. We have studied the effects of autologous platelets, electroloaded with the stable prostacyclin analogue, iloprost on platelet deposition and neointima formation in a pig carotid angioplasty model. Iloprost loaded or control platelets were delivered locally and immediately to the balloon injured site using a double balloon delivery catheter. Acute platelet deposition was measured using 111-Indium, and neointima formation at 21 days post angioplasty was assessed by morphometric analysis. In pigs treated with iloprost loaded platelets, platelet deposition on the artery at 2 hours post injury was dramatically reduced (to approximately monolayer coverage), when compared with arteries from pigs treated with control platelets. In pigs with deeply injured arteries, i.e. with extensively ruptured internal elastic lamina (IEL), platelet deposition was reduced by 88% compared with control arteries (118 +/- 20 x 10(6)/cm vs. 14 +/- 2 x 10(6)/cm, means +/- SI, 2P < 0.001). In minimally injured arteries (IEL intact) a 65% reduction in platelet deposition was observed (55 +/- 24 x 10(6)/cm vs. 19 +/- 3 x 10(6)/cm. 2P < 0.002). A high concentration of free iloprost, delivered to the angioplasty site, with control platelets, had far less effect on platelet deposition, substantiating the advantage of platelet encapsulation. At 21 days post injury, morphometry of the carotid arteries after treatment with iloprost loaded platelets showed significant reductions in intimal area and intimal/medial ratios in minimally injured vessels (P < 0.05) as compared with vessels from pigs treated with control platelets. With deeply injured vessels, the mean differences (control vs. treated) for the same morphometric parameters were not significant. This novel approach of electro-encapsulating drugs within autologous platelets, and using them as highly biocompatible and biodegradable drug targeting vehicles might, with the appropriate choice of encapsulated agent, have potential for reducing the incidence of occlusion after angioplasty and thrombolysis procedures.

Animals↗
PubMed1997

[Measurement of skin temperature as a method of detecting febrile diseases in swine].

The objective of the study was to determine whether precise estimation of rectal temperature of pigs is possible by taking their skin temperature in consideration of different factors as body weight, ambient temperature and relative air humidity. Therefore skin temperature of 272 pigs (7-222 kg BW) was measured by direct (thermo couple element) and indirect (infrared thermometer) methods at distinct localisations. In order to investigate different stages of pyretogenesis Escherichia coli endotoxin was administered to 30 of the pigs intravenously. A significant influence on skin temperature could be ascertained for the ambient temperature and the body weight, but not for the relative air humidity. From these data equations were established to estimate rectal temperature (RT) by measurement the skin temperature (ST) at the base of the ear: 1. Weaners and fattening pigs: RT = ST + 21.867 - 0.089x1 - 0.432x2 + 0.009x3, (r = 0.703) 2. Sows: RT = ST + 31.511 - 0.074x1 - 0.657x2 - 0.011x3, (r = 0.641) (x1 = ambient temperature, x2 = skin temperature, x3 = body weight) In spite of consideration of ambient temperature and body weight estimation of the rectal temperature was not suitable for clear detection of febrile pigs. Only in 35.45% of the younger pigs and in 29.30% of the sows a definite diagnose (fever yes/no) could be made. This method can only be used as a screening in the herd, if estimation of extreme values allowed the recognition of febrile illness. A follow-up control of the rectal temperature is always necessary in groups of animals, where estimations give no clear results.

Aging↗
PubMed1997

[Toxicity of the combination of salinomycin and tiamulin in swine].

The toxicity of the combination of salinomycin (sal.) and tiamulin (tia.) was investigated in dependence upon dosage and feeding method. In addition the efficacy of a safe dose for prophylactic treatment of dysentery was controlled. Following feed medications were tested for toxic effects in pigs: a) 3 mg sal. + 5 mg tia./kg BW, b) 3 mg sal. + 3 mg tia./kg BW, c) 3 mg sal. + 1 mg tia./kg BW, d) 3 mg sal./kg BW, e) 10 mg tia./kg BW, f) 30 mg tia./kg BW. The daily dose was given for 2 weeks by restricted feeding (twice a day) either as bolus or mixed in the whole ration or by feeding ad libitum. Animals were controlled for clinical symptoms and activities of creatine phosphokinase (CK) and aspartate aminotransferase (ASAT) were evaluated daily. Main clinical signs of poisoning were loss of appetite and locomotor disturbances and could be noticed for dosages of 8, 6 and 4 mg sal. + tia./kg BW. Activities of CK and ASAT were increased dose-related, the feeding method also had an influence on the degree of intoxication. Some animals showed locomotor disturbances without any corresponding changes of CK and ASAT levels. Single pigs remaining without any symptoms even at high dosage pointed to differences in individual susceptibility. Toxicity was not found to be age dependent. Feed medication with 60 ppm sal. + 20 ppm tia. (feeding ad libitum) did not result in any signs of toxicity, however, the transmission of Serpulina hyodysenteriae from infected pigs to healthy, treated control animals could not be inhibited efficiently. Therefore the simultaneous application of salinomycin and tiamulin should be avoided generally, because the risk of intoxication is high and subtherapeutical dosage has an insufficient effectiveness against Serpulina hyodysenteriae.

Animals↗
PubMed1996

[Spinal para-medullary conduction anesthesia in therapy with anticoagulant drugs].

Epidural and spinal blocks can lead to iatrogenic bleeding in the spinal canal. Incidence of this severe complication is considered low, but the risk of irreversible neurological defects for the patient requires increased attention by the anaesthetist. The perioperative risk is higher in patients under anticoagulant therapy. The different pharmacodynamics and pharmacokinetics of practically relevant anticoagulants are discussed and recommendations for the performance of centroneuraxis blocks in patients under anticoagulant therapy are given.

Anesthesia, Epidural↗
PubMed1996

[Crystalluria in sows].

In 12 breeding sows the influence of high feed levels of calcium (Ca 16.0 mg/kg, P 5.9 mg/kg, Ca/P ratio 2.71:1), of a mineral feed mixture (Ca 13.8 mg/kg, P 8.3 mg/kg, Ca/P ratio 1,66:1) and of phosphorus (Ca 7.0 mg/kg, P 11.0 mg/kg, Ca/P ratio 0.64:1) on blood concentrations and renal excretion of minerals (Ca, P, Mg), electrolytes (Na, K) as well as development of urine concrements (crystalluria) was investigated in comparison to a control feed (Ca 7.3 mg/kg, P 6.0 mg/kg, Ca/P ratio 1.23:1). Besides the effect of water supply on formation of crystalluria was tested. Studies showed that especially high levels of phosphorus in the feed are responsible for excretion of urinary crystals. Sediment consisted of Ca phosphates mainly, which could be detected as amorphous crystals microscopically. Alkaline pH values in urine and an insufficient water supply supported development of crystalluria, but formation of crystals differed greatly between individuals. Cystoscopic investigations demonstrated inflammatory alterations of the bladder mucosa in sows with crystalluria. Therefore crystalluria in sows has to be considered as a risk factor for urinary tract infections.

Animal Feed↗
PubMed1995

Clinical, and light and electron microscopical findings in sows with cystitis.

The clinical findings, and urinary and morphological changes in the urinary bladder were investigated in 25 sows with a urinary tract infection. Eubacterium suis was isolated from 12 of the sows but not from the other 13. The clinical signs did not always correlate with the morphological changes. The only clinical sign indicating the beginning of cystitis appeared to be a significant bacteriuria. Other urinary changes occurred later when the inflammatory processes were more severe. In contrast with cystitis due to other bacteria, infection with E suis frequently resulted in a macrohaematuria and urinary pH values above 8.0. However, the light and electron microscopical findings in the bladder mucosa were similar in the sows with and without cystitis due to E suis. The transformation of goblet cells and the development of mucin cysts were probably due to the local bladder defence mechanisms. More severe lesions were observed with E suis infections, which resulted in changes in the ureterovesical junctions and in ascending renal infection and uraemia.

Animals↗
PubMed1995

[Light- and electron-microscopic studies of the structure of normal bladder epithelium in female swine].

A light- and electron-microscope investigation was performed to examine the normal structure of the porcine urinary bladder. Tissue biopsies were studied obtained from 10 healthy female pigs (four weanling pigs, six sows). The bladder wall showed a typical stratification consisting of a tunica (t.) mucosae, t. submucosae, t. muscularis and t. serosa. The mucosa consisted of an epithelium transitionale, a lamina propria, and a lamina muscularis mucosae. The urothelium was composed of a basal layer, one or more intermediate layer(s), and a superficial layer. The urothelial cells of all layers were connected by desmosomes, while tight junctions linked adjacent superficial cells. Surface cells were lined by a layer of mucus, which is believed to provide an important barrier against bacterial infection. The surface of the superficial cells was also characterized by numerous irregularly arranged microplicae. By contrast, intermediate cells, which are assumed to be immature cell forms, showed microvilli-like structures. When desquamation of superficial cells takes place, differentiation of underlying intermediate cells is accompanied by merging of microvilli to form microplicae. The morphology of the bladder surface structures may play an important role in the ability of bacteria to adhere to the urothelium.

Aging↗
PubMed1995

[Serologic examinations for the detection of antibodies against Eubacterium suis in swine].

Determination of antibodies against Eubacterium suis (E. suis) in the serum of pigs was carried out by an indirect immunofluorescence test. Therefore 35 sows with urinary tract infections as well as 43 healthy control sows were investigated. E. suis could be detected in the urine of 19 sows. Serological results were compared with the bacteriological examinations. To reach a specificity of 100% for detection of animals actually infected with E. suis, titres from 1:16++ can be accepted as positive. Therefore sensitivity gave a level of 78.9%. Seroconversion and development of antibody titers were studied on 15 sows, which were experimentally infected with E. suis. Antibodies could be shown 3 weeks after infection at the earliest, they were preferably demonstrated in sows with a haemorrhagic cystitis. No correlation existed between the affection of the kidneys and the development and the level of titres respectively. Serological investigations can turn out negative in spite of E. suis infection, if immunological response still has not taken place or development of antibodies has failed to appear after short-time infection of the bladder.

Animals↗
PubMed1995

[The therapy of urinary tract infections in sows].

Fifteen sows spontaneously infected with Eubacterium suis were treated with enrofloxacin and, if necessary, with ampicillin. Before and after treatment different blood and urine parameters were determined with regard to renal function and the condition of the urinary bladder was examined by cystoscopy. Besides results of a controlled treatment in a breeding herd with a high frequency of urinary tract infections are referred. Duration of treatment with appropriate dosage should be at least 10 days. Even when a haemorrhagic inflammation was present therapy of infections with Eubacterium suis showed no problems, if the alterations were restricted to the bladder. In sows with renal insufficiency in case of ascending infection treatment is also possible on principle, but intensive infusion therapy is necessary in addition to antibiosis. Reliable estimation of the renal function can be obtained by measurement of creatinine and urea blood levels. Enrofloxacin treatment of urinary tract infections was successful in a breeding herd. An insufficient water supply and a high incidence of crystalluria were important predisposing factors.

Ampicillin↗
PubMed1994

Successful long-term course after heart transplantation for anthracycline cardiomyopathy in a young boy despite neurological complications.

A now 14-year-old boy underwent orthotopic heart transplantation at the age of 13 for anthracycline cardiomyopathy which was a sequela of polychemotherapy for embryonal teratocarcinoma at the age of 1 year. Despite perioperative cerebellar infarction with signs of herniation which required emergency right cerebellar hemispherectomy the long-term course after 18 months turned out to be favorable with complete medical and psychosocial rehabilitation.

Adolescent↗
PubMed1994

[Anesthesiological risks in neurologic diseases].

For an exact evaluation of the risks of operations it is necessary to assess both co-existing and concomitant diseases before the performance of anaesthesia. The relatively low incidence of neurological and muscular diseases (0.02 to 0.7/1,000) and the low probability of an operation of a patient suffering from these diseases lead to higher anaesthesiological risks during the operation and the perioperative period. The anaesthetist is usually not always aware of all the special pathophysiological problems which have to be taken into consideration when these patients have to be anaesthetized. In order to reduce the risk of anaesthesia of these patients, we discuss the most important of these uncommon neurological diseases regarding their special anaesthesiological management.

Anesthesia, General↗
PubMed1994

[Scanning electron microscopic studies of the urinary bladder of sows with special reference to a Eubacterium suis infection].

Scanning electron microscopy was performed on bladder biopsies from 20 sows with cystitis. Results were compared with those of healthy control animals. Biopsy specimens were taken from nine sows infected only with commensal bacteria (E. coli, streptococci, staphylococci) and from 11 sows, where Eubacterium suis (E. suis) was involved in urinary tract infection and had caused a haemorrhagic cystitis. Increased losses of normal superficial cells covered with microplicae could be seen depending on the degree of cystitis. Desquamation of the surface layer exposed smaller cells patterned with short microvilli. These cells were presumed to be immature intermediate cells and goblet cells. Goblet cells were found only in infected organs. The varying surface structure of epithelial cells in relation to receptor quality is important for the bacterial adherence to bladder mucosa. All examined bladders infected with E. suis showed a total loss of superficial cells. Luminal cells covered with multiple short microvilli were accompanied by cells with long pleomorphic processes. Accumulating cell necrosis was indicated by a smooth surface structure. Funnel-shaped orifices between the epithelial cells were identified as excretory ducts of mucus-filled cysts, which are formed by the confluence of degenerating goblet cells. E. suis infection of the porcine bladder causes more severe alterations than infections due to other bacteria. However, debilitation of the urothelium due to previous infection is necessary to support infection of the bladder with E. suis.

Animals↗
PubMed1994

[The effect of treatment with vitamin E or selenium on the course of salinomycin poisoning in swine].

Experimentally induced salinomycin toxicosis in weanling pigs showed typical clinical signs of an intoxication with a polyether antibiotic. Severe ataxia and recumbency were the most prominent symptoms, which could be attributed to acute skeletal muscle necrosis by estimation of muscle enzyme activities (creatine kinase, aspartate aminotransferase) and histopathological examination. Intoxication had neither influence on concentrations of vitamin E and selenium-dependent glutathione peroxidase in plasma and different organs nor on contents of fatty acids in skeletal muscles. No signs of increased lipid peroxidation in muscle tissue could be found. Prophylactic application of vitamin E or selenium one day before administration of salinomycin as well as treatment on the following days produced no protective effects. The treated pigs showed equal clinical and pathomorphological alterations as the untreated animals, although applications caused a significant increase of alpha-tocopherol and glutathione peroxidase concentrations in blood and different organs.

Animals↗
PubMed1993

Ventilation with positive end-expiratory airway pressure causes leukocyte retention in human lung.

We examined the effect of assisted ventilation with different positive end-expiratory airway pressures (PEEP) on pulmonary leukocyte retention in humans after cardiopulmonary bypass. Eight patients who underwent heart surgery were ventilated in the postoperative phase briefly with 10 (39.6 +/- 0.9 s) and 20 cmH2O (40.3 +/- 1.0 s) PEEP. Before, during, and after this ventilatory maneuver, blood was withdrawn simultaneously from catheters placed in the pulmonary and radial arteries for blood cell differentials. At the same time points, pulmonary and systemic hemodynamics were recorded. During PEEP ventilation, there was a four- (10 cmH2O PEEP) and an eightfold (20 cmH2O PEEP) increase in mixed venous-arterial leukocyte cell difference compared with baseline. This phenomenon was based mainly on a transpulmonary cell difference of polymorphonuclear cells. Likewise, the lymphocytes were entrapped in the pulmonary vasculature during PEEP ventilation. During the ventilatory maneuver, the pulmonary blood flow was significantly reduced; it was indexed by a declined cardiac output. We conclude that PEEP ventilation in the post-operative phase after cardiopulmonary bypass causes pulmonary polymorphonuclear cell entrapment. The most likely mechanism for this phenomenon is the compression of alveolar capillaries and reduced pulmonary blood flow in response to the raised alveolar pressure.

Adult↗
PubMed1993

Studies on the prevalence of Eubacterium suis in boars on farms in Brazil, Portugal and Argentina by indirect immunofluorescence technique.

The main habitat of Eubacterium suis (E. suis) is the preputial diverticulum of male pigs. E. suis can be transmitted from boars to the vestibule of sows at the time of mating and ascending urinary tract infections in sows may result. A total of 195 swabs of the preputial diverticulum was collected for prevalence studies of E. suis infections in adult breeding males on Brazilian (n = 96 boars), Portuguese (n = 78 boars) and Argentinian (n = 21 boars) farms. The fixed smears were stored at 4 degrees C for one to four months until indirect immunofluorescence test was performed. Eubacterium suis was found in 75 (78%), 52 (67%) and 16 (76%) boars, respectively. These results indicate that E. suis is present in Brazil, Argentina as well as in Portugal and may be involved in urinary tract infections of sows more frequently as it is known till now.

Animals↗