Biomedical subjects

T Foitzik

Publications and source records attributed to T Foitzik.

At least 37 records · Page 2Linked to original sources

PubMed2000

[Multiple organ failure in experimental pancreatitis].

BACKGROUND: Multiple organ failure (MOF) is the most severe complication and the most frequent cause of death in acute necrotizing pancreatitis (ANP). OBJECTIVE: To evaluate the components and the time course of MOF in an experimental model of ANP. METHOD: Induction of ANP in rats by a standardised bile-salt infusion into the pancreatic duct and i.v. cerulein hyperstimulation. Six hours after AP-induction animals were randomised into 4 groups to receive (I) no therapy; (II.) 4 ml/kg/h Ringer lactate (R.L) i.v.; (III) 8 ml/kg/h RL i.v.; or (IV) 4 ml/kg/h RL plus an endothelin receptor antagonist. Animals were observed for 24 hours and vital parameters were investigated. RESULTS: After 6 hrs all animals presented with severe haemoconcentration (hematokcrit > 57%) and oliguria (< 0.5 ml/6 hrs). Until 12 hrs following AP-induction in animals without therapy increased hematocrit and oliguria was observed. Animals receiving fluid resuscitation had a significant drop in hematocrit and kept their blood gas values compensated. Between 12 and 24 hrs urine production significantly increased with fluid resuscitation and respiratory parameters stabilised except for animals treated with 8 ml/kg/h RL. These animals developed arterial hypoxia and hypercapnia. CONCLUSIONS: (1) In the early phase of ANP in our model renal failure developed. (2) Massive fluid resuscitation that is necessary to increase urine output may lead to respiratory distress. (3) Reduction of intravascular fluid loss by endothelin receptor blockade is associated with improved renal and respiratory function.

Acute Kidney Injury↗

PubMed1999

Does microcirculation play a role in the pathogenesis of inflammatory bowel diseases? Answers from intravital microscopic studies in animal models.

The potential role of intestinal microcirculation for the development of inflammatory bowel diseases (IBD) has not been systematically investigated, mainly because of methodological problems. Using a well-established rodent model of IBD and intravital microscopy, the present study investigated whether (and when) gut microcirculation is disturbed in IBD, and whether microcirculatory disorders contribute to histological and functional alterations in the development of IBD. Colitis was induced by rectal injection of trinitrobenzene sulfonic acid. After 1, 3, and 15 days rats were laparotomized for intravital microscopic determination of mucosal colonic blood flow. In a second series it was examined whether enhancing colonic capillary blood flow by hemodilution therapy stabilizes colonic wall resistance and other electrophysiological parameters of gut permeability. Additional measurements involved hemodynamic monitoring and histological examinations. Colonic capillary blood flow was significantly decreased 3 days after colitis induction (1.8 +/- 0.05 vs. 2.6 +/- 0.04 nl/min in healthy control animals) when histology revealed signs of acute inflammation, and normal values after 15 days (2.4 +/- 0.06 nl/min) when chronic histological changes were evident. Hemodilution therapy enhanced colonic capillary blood flow in the initial stage (2.1 +/- 0.02 vs. 1.6 +/- 0.02 nl/min in saline-treated animals with trinitrobenzene sulfonic acid colitis) and improved gut resistance and electronic chloride secretion (73 +/- 15 vs. 33 +/- 8 microA cm2). Histological alterations were not significantly attenuated. Impaired colonic capillary blood flow in the initial stage of experimental colitis and improved mucosal microcirculation with stabilized gut permeability suggests that the early microcirculatory disturbances precede chronic histological changes and influence functional alterations in the course of the disease. Research should be continued in this field because important mechanisms in the pathogenesis of IBD and potentially therapeutic (vasoactive) substances may otherwise be overlooked.

Animals↗

PubMed1999

Does glutamine reduce bacterial translocation? A study in two animal models with impaired gut barrier.

Failure of intestinal barrier function and subsequent translocation of bacteria from the gut are believed to play a decisive role in the development of systemic septic complications, for example, following major trauma or major abdominal surgery. This study evaluated: (a) the effect of glutamine on colonic microcirculation and electrophysiological parameters reflecting gut barrier function, (b) the translocation of live bacteria to extraintestinal organs, and (c) disease outcome in two animal models with impaired gut barrier function. Severe acute pancreatitis or colitis was induced in rats randomized for therapy with or without glutamine (0.5 g/kg daily). After 48 h one animal group was prepared for intravital microscopy of colonic capillary blood flow and electrophysiological measurement of gut permeability; another was killed after 96 h for histological and microbiological examination. In animals with pancreatitis, glutamine (Gln) supplementation significantly improved gut permeability, i.e., Gln increased colonic transmucosal resistance from 67+/-7 to 92+/-3 Omega/cm(2) and decreased mannitol flux through the epithelium by 53%. Capillary blood flow in the colonic mucosa was improved by 25%. The prevalence of pancreatic infections was reduced from 86% in animals on standard parenteral nutrition to 33% in animals given the Gln-enriched diet (P<0.05); mortality decreased by 32%. In colitis, Gln had no significant effect on these parameters except for improving colonic capillary blood flow in colon segments not adjacent to the major injury site. Glutamine supplementation improves colonic capillary blood flow, stabilizes gut permeability, and reduces secondary pancreatic infections and mortality in severe rodent pancreatitis, but it is not helpful in colitis. This confirms previous reports that glutamine stabilizes gut barrier function only in certain diseases. Our experimental data strongly suggest that acute pancreatitis (rather than colitis) is one of the diseases with gut barrier dysfunction in which glutamine substitution may be helpful to reduce bacterial translocation and should therefore be tested in a controlled clinical trial.

Animals↗

PubMed1999

Systemic lymphocyte activation modulates the severity of diet-induced acute pancreatitis in mice.

To examine the role of lymphocyte activation in the development of local and systemic complications in acute pancreatitis, we compared disease severity of choline-deficient, 0.5% ethionine supplemented (CDE) diet-induced acute pancreatitis in T- and B-cell deficient SCID mice and immunocompetent C.B-17 mice. Twenty-five female SCID and 17 female C.B-17 mice were fasted for 24 h and fed a CDE diet for 72 h. Twenty SCID and 12 C.B-17 mice were bled and their organs removed for histologic evaluation. Five control animals of both kinds were fed a regular diet for 6 days. Lung, kidney, and pancreas were examined microscopically, and pancreatic damage scored. Apoptosis was detected by DNA nick-end labeling and confirmed by DNA laddering. Trypsinogen-activation peptide was measured by enzyme-linked immunosorbent assay (ELISA), and the catalytic activity of PLA2 was determined by a radiometric assay. Four-day mortality was 10% in SCID and 33% in C.B-17 mice, and 10-day mortality was 0 in SCID and 60% in C.B-17 mice. SCID mice had mild pulmonary damage, whereas pulmonary injury was severe in C.B-17 mice. Pancreatic damage was severe in both groups. Even though in situ staining of apoptotic cells was found in all pancreatitis animals, apoptosis was confirmed by DNA laddering only in C.B-17 mice. In SCID mice, apoptotic cell staining positively correlated with necrosis (r = 0.91; p < 0.001). Plasma TAP and PLA2 catalytic activity did not differ significantly between the groups. In conclusion, the absence of T and B lymphocytes prevents severe pulmonary injury resulting from acute pancreatitis but does not influence pancreatic or renal damage. Our results suggest that systemic lymphocyte activation does not affect the initiating events that trigger pancreatic injury but modulates the systemic response, in particular, pulmonary injury caused by acute pancreatitis.

Acute Disease↗

PubMed1998

Effect of different immunosuppressive agents on acute pancreatitis: a comparative study in an improved animal model.

BACKGROUND: Immunosuppressive drugs have been associated with the development and progression of acute pancreatitis after organ transplantation. Consequently, a reduction or a change in immunosuppressive therapy has been recommended once posttransplantation pancreatitis has been suspected. However, it is not known which of the available immunosuppressive agents is most harmful to the pancreas and which may be used safely in this situation. The objective of this study was to investigate the effect of different immunosuppressive drugs in various dosages on intrapancreatic protease activation, acinar cell necrosis, and mortality in an improved model of acute necrotizing pancreatitis in the rat. The rat model of acute necrotizing pancreatitis, like posttransplantation pancreatitis, is characterized by ischemia and microcirculatory disorders. METHOD: Acute pancreatitis was induced in rats by using a combination of low-dose controlled intraductal glycodeoxycholic acid superimposed on intravenous cerulein hyperstimulation. Six hours thereafter, animals were randomized to intravenous therapy with 2, 10, or 50 mg/kg/day prednisolone (PRED); 3, 15, or 60 mg/kg/day cyclosporine A (CsA); 10 mg/kg/day azathioprine (AZA); 0.6 mg/kg/day orthoclone OKT3 (OKT3); or saline. After 36 hr, surviving animals were killed to determine acinar cell necrosis and trypsinogen activation peptides levels (TAP) in blood and ascites. RESULTS: Compared with saline-treated control rats, animals treated with 60 mg/kg/day CsA developed significantly more acinar cell necrosis and had increased amounts of TAP in ascites. Likewise, there was more extensive acinar cell necrosis in animals subjected to AZA therapy. However, this was not associated with incremental TAP. Animals treated with 3 or 15 mg/kg/day CsA, OKT3, or PRED showed no significant changes in these target parameters. Animals given 10 or 50 mg/kg/day PRED even had decreased hematocrit values and produced significantly less ascites than animals in the other groups. CONCLUSION: The present results suggest that AZA and high doses of CsA aggravate acute pancreatitis and should, therefore, be avoided once posttransplantation pancreatitis has been suspected, whereas lower doses of CsA, OKT3, and PRED may be used safely. PRED can even be used at higher doses as may be required when graft rejection is suspected.

Acute Disease↗

PubMed1998

[Conversion of experimental research findings to treatment of acute pancreatitis].

Performing prospective, randomized controlled studies in patients with severe acute pancreatitis is limited due to low disease incidence and organizational and financial problems. Thus, animal models simulating the clinical condition have been developed for testing innovative therapeutic procedures. Despite objections regarding the applicability of data obtained from animal experiments to clinical practice, the experience gained from these studies could not only be used in clinical study proposals but also, in part, directly influenced the clinical management of acute pancreatitis. This is illustrated by studies regarding the influence of contrast medium, isovolemic hemodilution and various antibiotics.

Animals↗

PubMed1998

Retinoic acid receptor alpha mediates growth inhibition by retinoids in rat pancreatic carcinoma DSL-6A/C1 cells.

During carcinogenesis, pancreatic acinar cells can dedifferentiate into ductal adenocarcinoma of the pancreas. DSL-6A/C1 cells represent an in vitro model of this carcinogenic sequence. This study was designed to examine the effects of retinoids on cell growth in DSL-6A/C1 cells and to characterize further the molecular mechanisms underlying the antiproliferative actions of retinoids. Treatment of DSL-6A/C1 cells with retinoids results in a time- and dose-dependent inhibition of cell growth, paralleled by a retinoid-mediated transactivation of a pTK::betaRAREx2-luciferase reporter construct transiently transfected into DSL-6A/C1 cells. Retinoid receptor expression was evaluated by reverse transcriptase polymerase chain reaction (RT-PCR) using subtype-specific primers and demonstrated expression of retinoic acid receptor alpha (RAR-alpha), RAR-beta and retinoid X receptor alpha (RXR-alpha). Using a panel of receptor subtype-specific agonists, the RAR-alpha specific agonist Ro 40-6055 was the most potent retinoid in terms of growth inhibition. Furthermore, all-trans-retinoic acid-mediated growth inhibition and transactivation was completely blocked by the RAR-alpha-specific antagonist Ro 41-5253. In summary, the RAR-alpha subtype predominantly mediates the antiproliferative effects of retinoids in DSL-6A/C1 cells. Furthermore, this cell system provides a feasible tool to study the molecular mechanisms underlying the growth inhibitory effects of retinoids in ductal pancreatic carcinoma cells derived from a primary acinar cell phenotype.

Animals↗

PubMed1998

Endothelin receptor blockade improves fluid sequestration, pancreatic capillary blood flow, and survival in severe experimental pancreatitis.

OBJECTIVE: To evaluate the effect of a new endothelin receptor antagonist (ET-RA) on the course of severe experimental pancreatitis. BACKGROUND: Endothelin-1 has been shown to reduce regional blood flow in various organs, including the pancreas, and to aggravate cerulein-induced mild pancreatitis. METHODS: Acute necrotizing pancreatitis (ANP) was induced in rats by standardized intraductal bile acid infusion and cerulein hyperstimulation. Serum trypsinogen activation peptides (TAP) were measured to verify comparable disease severity. Starting 6 hours after the onset of ANP, animals randomly received either saline or the new ET-RA LU-135252. Monitoring included cardiorespiratory parameters, urine output, hematocrit, and TAP levels. After 24 hours, animals were relaparotomized to determine pancreatic capillary blood flow and to assess the amount of free intraabdominal fluid and acinar cell necrosis. Survival was determined in a second set of experiments on 24 animals observed for 48 hours after pancreatitis induction and treatment with either normal saline or ET-RA. RESULTS: Comparable TAP increases confirmed equally severe ANP in both groups before treatment. Treatment with ET-RA significantly reduced the mortality rate, from 50% in untreated animals to 8%. Improved survival was associated with significantly decreased hematocrit, improved urinary output, decreased ascites, and increased pancreatic capillary blood flow. There were no significant differences in plasma TAP and acinar cell injury in the surviving animals of the two treatment groups. CONCLUSION: Therapy with the new ET-RA reduces the early mortality rate in experimental ANP, probably by reducing fluid sequestration and improving microcirculation.

Acute Disease↗

PubMed1998

[Protective effect of glutamine on microcirculation of the intestine in experimental colitis].

Parenteral glutamine application can stabilize intestinal permeability and mucosal integrity. It is not known whether glutamine influences the microcirculation in the large intestine. This study thus employs intravital microscopy to investigate mucosal microcirculation in the ascending and descending Colon of Sprague-Dawley rats with TNBS colitis. The animals were randomized and treated with either saline solution (placebo) or glutamine (verum). In the severely inflamed descending colon, TNBS colitis involves a significant capillary blood flow reduction that is not improved by glutamine application. Though the ascending colon shows only a mild inflammatory reaction, its microcirculation is likewise significantly reduced. Here glutamine therapy is associated with an increase in capillary blood flow, indicating that it has a protective effect on the microcirculation of the secondarily involved intestinal segment.

Animals↗

PubMed1998

[Endothelin receptor block in acute pancreatitis--improvement of microcirculation and decrease of capillary permeability also distant from the pancreas].

We have previously demonstrated that therapy with a new specific endothelin-1 receptor antagonist (ET-RA) significantly reduced mortality in acute necrotizing pancreatitis (ANP) in the rat. Improved survival was not associated with decreased intrapancreatic trypsinogen activation or parenchymal necrosis but with reduced fluid sequestation into the third space suggesting that ET-RA counteracts systemic rather than local sequelae of severe pancreatitis. The present study further tests this hypothesis by evaluating the effect of the specific ET-1 antagonist LU-135252 on capillary blood flow, capillary density, and capillary permeability not only in the pancreas but also in the colon, and monitoring fluid losses and renal and respiratory function. The experiments demonstrate that therapy with the specific ET-RA started 6 hours after disease onset stabilizes increased capillary permeability in ANP not only in the pancreas but also in the colon. This is associated with reduced ascites and improved renal and respiratory function. Furthermore, ET-RA enhances decreased capillary blood flow and capillary density in the pancreas and colon. The present results are consistent with our previous observation that ET-RA improves outcome in ANP by counteracting systemic microcirculatory disorders (particularly capillary leakage) which are believed to contribute to organ failure in early pancreatitis in this model as well as in severe human pancreatitis.

Animals↗

PubMed1998

[Acute appendicitis. Analysis of surgical indications].

We analyzed 276 patients operated on for acute appendicitis between January 1995 and June 1997. In 26 patients intraoperative assessment revealed a pathological finding other than appendicitis. Fifty-nine patients (24%) had a perforated appendix, 116 acute appendicitis verified by histological examination, 75 (30%) chronic fibroplastic appendicitis or no signs of appendicitis. Patients with histologically acute inflammation fulfilled more clinical criteria of appendicitis than those without (5.1 vs. 3.7). Negative histological findings were most common in younger females admitted on Mondays and Tuesdays. Clinical observation rather than immediate operation and laparoscopy rather than laparotomy appear appropriate for the latter group and may lower the rate of negative appendectomy.

Acute Disease↗

PubMed1998

[Pancreatitis and translocation--approaches for nutritional strategies].

Translocation of intestinal bacteria from the gut into pancreatic necrosis is an important factor in the development of septic complications in acute pancreatitis. Bacterial translocation is promoted by an impaired intestinal mucosal barrier, which can be attributed to the reduced oxygen and substrate supply of the intestine. A rat model of severe acute pancreatitis has been used to confirm the hypothesis that an impaired mucosal barrier can be stabilized by supplying certain nutrients, vitamins, and trace elements. A reduction in secondary pancreas infections with intestinal bacteria and improved survival was achieved under intravenous glutamine substitution, an essential amino acids in stress situations for enterocytes, colonocytes and immunocompetent cells. The positive experimental results are currently being investigated in a controlled randomized multicenter trial. Comparable studies need to be performed for verifying the effect of other nutritive factors on bacterial translocation and the disease course in acute pancreatitis.

Animals↗

PubMed1998

[Endoscopic cholecystectomy as cost assessment--still a learning intervention?].

Economic considerations are putting increasing pressure on surgical departments to avoid intra- and postoperative complications and thus additional costs. Under this aspect, it was investigated whether laparoscopic cholecystectomy is a suitable training intervention for young prospective surgeons. These physicians in advanced training did not have a higher intra- or postoperative complication rate in a preselected patient population than senior physicians or specialists. The additional costs per surgical intervention due to longer operation times required by young physicians were acceptable so that laparoscopic cholecystectomy as a training intervention for young colleagues can be justified.

Cholecystectomy, Laparoscopic↗

PubMed1997

[New aspects in the pathophysiology of chronic pancreatitis].

Despite numerous experimental and clinical investigations there is no consensus on the evolution of chronic pancreatitis (CP). In the 1970s and 1980s, Sarles persistently emphasised the de novo evolution of CP due to pancreatolithiasis. In recent years, however, clinical and morphological studies have provided strong evidence for the initial proposal of acute pancreatitis progressing to chronic pancreatitis. The so-called necrosis-fibrosis-sequence theory is supported by immunohistochemical work suggesting that inflammatory mediators primarily contribute to tissue destruction and that infiltration of pancreatic nerves by immune cells is a pathogenetic factor for the generation of pain in CP. While Sarles postulates that acinar hypersecretion and an imbalance of pancreatic stone promoting and inhibiting factors trigger the evaluation of CP, the necrosis-fibrosis-sequence theory also involves other pathomechanisms (e.g. changes in ductal permeability, ischemia, oxidative stress) which have been shown to cause (acute) pancreatic injury. Despite this unifying template, which also lessens the need to identify independent mechanisms for the pathogenesis of acute and chronic alcoholic pancreatitis, there are still open questions, e.g. on genetic factors that (like in hereditary CP) may explain the different susceptibility of the pancreas to injury and the individual immunological response.

Cholelithiasis↗

PubMed1997

Influence of changes in pancreatic tissue morphology and capillary blood flow on antibiotic tissue concentrations in the pancreas during the progression of acute pancreatitis.

BACKGROUND: The ability of an antibiotic to reach bactericidal concentrations in tissue depends on numerous factors including tissue composition and regional perfusion. Although necrotising pancreatitis is characterised by progression of pancreatic necrosis over at least 96 hours and microcirculatory alterations, the impact of these changes on the concentration of antibiotics in the pancreas has not yet been investigated. AIM: To determine and compare pancreatic tissue concentrations of imipenem and cefotaxime at different stages of acute necrotising pancreatitis in an animal model that has been shown to mimic closely the pathomorphological and bacteriological features of severe human pancreatitis. METHOD: Acute necrotising pancreatitis was induced in rats by a standardised intraductal infusion of glycodeoxycholic acid and intravenous cerulein. Six hours (n = 16) and 48 hours (n = 16) after induction of pancreatitis, the animals were randomised for intravenous therapy with either imipenem or cefotaxime. Fifteen minutes after injection of the antibiotic, the animals were killed. Blood and the head of the pancreas were collected for determining imipenem or cefotaxime in serum and tissue; the splenic portion of the pancreas was prepared for histological examination. In an additional set of identically treated animals, pancreatic capillary blood flow (PCBF) was assessed by intravital microscopy before induction of acute necrotising pancreatitis and at the time of antibiotic therapy. RESULTS: Imipenem accumulates in the pancreas in the initial phase of acute necrotising pancreatitis characterised by pronounced oedema and decreased PCBF, and tends to decrease with resolution of the oedema and the progression of acinar cell necrosis in the later course of the disease. Concentrations of cefotaxime are low in oedematous pancreatic tissue early after induction of acute necrotising pancreatitis and increase with the resolution of oedema and normalisation of PCBF. CONCLUSIONS: Concentrations of antibiotics in the pancreas vary in acute necrotising pancreatitis, depending on changes in pancreatic tissue morphology and capillary blood flow. This suggests that antibiotic tissue concentrations may not be consistent from one agent to another and that efficacy of antibiotics in acute pancreatitis cannot be estimated solely on the basis of their pharmacological and microbiological properties.

Acute Disease↗

PubMed1997

[Between bench and bedside: examples of clinically oriented basic surgery research].

Animal experimental studies are an effective modality for testing new therapeutic strategies, provided that the animal model and the study protocol simulate the clinical situation. This is exemplified by various animal experimental studies on the therapy of infectious complications in acute necrotizing pancreatitis that were performed preliminary or supplementary to clinical studies. The results show that basic surgical research with close clinical orientation can be usefully and fruitfully combined with clinical studies and enables the academically active young surgeon to overcome the dualism between laboratory work and clinical practice.

Animals↗

PubMed1997

[Surgical research with limited resources: research concepts and research cooperation in a surgical University Clinic].

The decreasing financial support of surgical research requires new strategies and, in particular, an intensive collaboration with basic science and biotechnology. This concept of "lean research" includes output-orientated research activities, which can be measured, using the "impact factor". Effective research requires a well-organized and structured department.

Cost-Benefit Analysis↗

PubMed1996

Improvement of pancreatic capillary blood flow does not augment the pancreatic tissue concentration of imipenem in acute experimental pancreatitis.

BACKGROUND: Acute necrotizing pancreatitis (ANP) is characterized by decreased capillary pancreatic blood flow. Thus, antibiotics may not reach pancreatic necrosis in therapeutic concentrations and consequently fail to prevent bacterial infection of the pancreas which today is the major cause of morbidity and mortality in ANP. OBJECTIVE: To evaluate whether improvement of impaired pancreatic microcirculation by isovolemic hemodilution with dextran leads to an increase in the pancreatic tissue concentration of imipenem (IMI), an antibiotic widely used in clinical ANP. METHOD: After induction of ANP rats were randomized for either standard fluid therapy with Ringer's lactate (RL) or isovolemic hemodilution with dextran 70,000 (IHD/DEX). Thereafter the animals received an intravenous injection of IMI, and 15 min later they were sacrificed for determination of IMI in serum and tissue. Capillary pancreatic blood flow (CPBF) at the time of antibiotic therapy was assessed by intravital microscopy in an additional set of animals. RESULTS: There was no significant difference in the pancreatic tissue concentration of IMI in animals pretreated with either RL (11.7 +/- 0.6 micrograms/g) or IHD/DEX (11.4 +/- 1.4 micrograms/g), although CPBF was significantly increased in the latter group (1.3 +/- 0.05 vs. 0.8 +/- 0.04 nl/min/capillary). CONCLUSION: (1) IMI is concentrated by the pancreas in experimental ANP despite impaired CPBF. (2) Enhancement of pancreatic capillary blood flow by IHD/DEX does not increase the pancreatic tissue concentration of IMI. This suggests that CPBF is not a decisive factor influencing the accumulation of this antibiotic in the pancreas, which may be one reason for the high efficacy of IMI in clinical ANP.

Acute Disease↗