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Biomedical subjects

E Wenzl

Publications and source records attributed to E Wenzl.

At least 37 records · Page 2Linked to original sources
PubMed1999

Effects of substance P on human colonic mucosa in vitro.

Previous studies indicated that the peptide substance P (SP) causes Cl--dependent secretion in animal colonic mucosa. We investigated the effects of SP in human colonic mucosa mounted in Ussing chamber. Drugs for pharmacological characterization of SP-induced responses were applied 30 min before SP. Serosal, but not luminal, administration of SP (10(-8) to 10(-6) M) induced a rapid, monophasic concentration and Cl--dependent, bumetanide-sensitive short-circuit current (Isc) increase, which was inhibited by the SP neurokinin 1 (NK1)-receptor antagonist CP-96345, the neuronal blocker TTX, the mast cell stabilizer lodoxamide, the histamine 1-receptor antagonist pyrilamine, and the PG synthesis inhibitor indomethacin. SP caused TTX- and lodoxamide-sensitive histamine release from colonic mucosa. Two-photon microscopy revealed NK1 (SP)-receptor immunoreactivity on nerve cells. The tyrosine kinase inhibitor genistein concentration dependently blocked SP-induced Isc increase without impairing forskolin- and carbachol-mediated Isc increase. We conclude that SP stimulates Cl--dependent secretion in human colon by a pathway(s) involving mucosal nerves, mast cells, and the mast cell product histamine. Our results also indicate that tyrosine kinases may be involved in this SP-induced response.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1998

Establishment of primary cultures from human colonic tissue during tumor progression: vitamin-D responses and vitamin-D-receptor expression.

Primary cultures derived from pre-cancerous and cancerous human colon tissue are essential for understanding normal and abnormal growth function in the large intestine. Here presented are (i) the methodology for routine establishment of primary cultures of normal, adenoma- and carcinoma-derived cells, and (ii) data for the apparently protective role of vitamin-D compounds in colon carcinogenesis. The steroid hormone 1,25-dihydroxyvitamin D3 and some non-hypercalcemic analogs reduce the high mitotic rate of adenoma cells to that of normal colonocytes. After vitamin-D treatment, tumor cells are less proliferative and differentiation is enhanced. Primary-colon-cancer cultures display a mosaic pattern of vitamin-D-receptor expression, at the mRNA level and at the protein level, with varying intensity of expression in positive cells. This suggests that, in human colorectal tumors in vivo, a large fraction of cells will respond to genomic action of vitamin-D compounds.

Antineoplastic Agents↗
PubMed1998

P-glycoprotein-mediated multidrug resistance is modulated by pretreatment with chemosensitizers in HCT-8 carcinoma cells in vitro.

The effects of pretreatment with the multidrug resistance (MDR) modulators verapamil (VPM), tamoxifen (TMX), cyclosporin A (CsA), and SDZ PSC833 (PSC) on drug sensitivity of the P-glycoprotein (Pgp) expressing human ileocecal carcinoma cell line HCT-8 is described. Following pretreatment of 2, 16 and 48 h with the individual modulators, rhodamine 123 efflux (RHO), transepithelial vinblastine transport (VIN) across treated HCT-8 monolayers, and chemosensitivity to doxorubicin (DOX) were determined and compared to Pgp protein expression and phosphorylation. After 2 h, VPM, TMX, CsA and PSC inhibited RHO efflux and VIN transport and increased the chemosensitivity of HCT-8 to DOX significantly. Prolonged exposure failed to further increase inhibition of Pgp-mediated transport, but in contrast maximized phosphorylation of Pgp (16 h) and Pgp protein expression (48 h), respectively.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Achalasia. Results of myotomy and antireflux operation after failed dilatations.

OBJECTIVE: To evaluate the outcomes of patients with achalasia who had undergone myotomy and an antireflux operation because dilatations had not yielded satisfactory results. DESIGN: Retrospective analysis. SETTING: University-based tertiary care center. PATIENTS: Of 39 patients who met inclusion criteria, 18 female patients and 18 male patients (age range; 17-85 years; median age, 54 years; range of time elapsed since operation, 1-22 years; median time, 6 years) could be studied. Antireflux operations included 360 degrees fundoplications in 27 patients, anterior hemifundoplications in 5 and other procedures in 4. MAIN OUTCOME MEASURES: Dysphagia for solid foods and liquids, regurgitation, heartburn, retrosternal pain and body weight. RESULTS: Excellent, good, and fair results of myotomy and antireflux operation were encountered in 14, 3, and 6 patients, respectively, and poor or absent results in the remaining 13 patients. The resting pressure of the lower esophageal sphincter was significantly lower at follow-up than preoperatively, and this was associated with reduced dysphagia for solid foods in 14 patients and for liquids in 16 of 17 patients. CONCLUSIONS: Myotomy and antireflux operation yielded excellent to fair results in 23 patients in whom dilatations had not facilitated swallowing. Poor results in the remaining 13 patients seemed to be attributable to the 360 degrees fundoplication performed in 12 of them. In these patients, a further surgical intervention seemed to be indicated.

Adolescent↗
PubMed1997

[Removal of the small intestine in autologous jejunum transplantation for reconstruction of the mouth cavity is a secondary intervention with few complications].

Reconstruction after radical tumor resection in the oropharyngeal region still represents an interdisciplinary challenge. Autotransplantation of the jejunum is a popular procedure, in which the abdominal surgeon's main task is that of harvesting enteral tissue. To evaluate this technique, a careful analysis of accompanying perioperative abdominal complications was performed. Additionally, we reexamined 35 of 66 patients still living after a follow-up period of 21 (range 2-63) months on average. The perioperative mortality of 90 patients treated for oropharyngeal malignancy using the described procedure was 7.8%. None of the perioperative deaths was caused by an abdominal complication associated with enteral resection. One abdominal reoperation was performed because of abdominal wall dehiscence. For reasons not related to enteral resection, four further patients had to be relaparotomized, two of them during their hospital stay and two after leaving hospital. In five cases we observed minor complications which could be treated nonsurgically. In the follow-up reexamination we detected no abdominal late-onset complication except small incisional hernias in six cases. Finally, we concluded that despite an elevated overall operative risk in this population, complications owing to jejunal resection were comparably low. The data regarding the rate of complications classify jejunal resection as a safe procedure for reconstructive purposes in patients suffering from oropharyngeal malignancy.

Adult↗
PubMed1997

Association of midoesophageal diverticula with oesophageal motor disorders. Videofluoroscopy and manometry.

PURPOSE: To evaluate the prevalence and clinical significance of associated oesophageal motor disorders in patients with midoesophageal diverticula. MATERIAL AND METHODS: We retrospectively reviewed videofluoroscopic and, if available, manometric studies of 30 patients with midoesophageal diverticula. The type of diverticulum and the presence and nature of oesophageal motor disorders were assessed. RESULTS: Videofluoroscopy showed that 24 patients had 26 pulsion-type diverticula and 6 patients had 7 traction-type diverticula. Oesophageal motor disorders were demonstrated in 21 of the 24 patients with pulsion-type diverticula and in 3 of the 6 with traction-type diverticula. Nineteen patients had nonspecific motor disorders, 5 had achalasia, and 5 had gastrooesophageal reflux or oesophagitis. CONCLUSION: Midoesophageal diverticula are most often of the pulsion-type and tend to be associated with an oesophageal motor disorder. Motor disorders are predominantly nonspecific, but achalasia may be encountered as well.

Adult↗
PubMed1997

Epidermal growth factor attenuates Clostridium difficile toxin A- and B-induced damage of human colonic mucosa.

Epidermal growth factor (EGF) exhibits a cytoprotective effect on gastrointestinal epithelia via a receptor-mediated mechanism. We investigated the effect of EGF on Clostridium difficile toxin A (TxA)- and toxin B (TxB)-induced damage of human colon. Ussing-chambered colonic mucosa was exposed serosally to EGF before and during luminal exposure to TxA and TxB. Resistance was calculated from potential difference and short-circuit current. Epithelial damage was assessed by light microscopy and alteration of F-actin by fluoresceinated phalloidin. Luminal exposure of colonic strips to TxA and TxB caused a time- and dose-dependent decrease in electrical resistance, necrosis and dehiscence of colonocytes, and disruption and condensation of enterocyte F-actin. These effects were inhibited by prior, but not simultaneous, serosal application of EGF (20 nM). Administration of the tyrosine kinase inhibitor genistein (10(-6) M) inhibited the protective effects of EGF. We conclude that EGF protects against TxA and TxB probably by stabilizing the cytoskeleton, the main target of these toxins.

Actins↗
PubMed1997

Effect of growth factors on epithelial restitution of human colonic mucosa in vitro.

BACKGROUND: Epithelial restitution enables resurfacing of epithelial discontinuities by enterocyte migration. This study investigated the effect of basic fibroblast growth factor (bFGF), insulin-like growth factor (IGF-1), and epidermal growth factor (EGF) on restitution of human colonic mucosa in vitro. METHODS: After base-line incubation human colonic mucosal strips, mounted in Ussing chambers, were luminally exposed to 0.5 mM sodium deoxycholate (NaDOC) for 10 min. Thereafter tissues were incubated with buffer alone or luminal buffer containing various concentrations of bFGF, IGF-1, and EGF for 3 h. Resistance (R) was calculated from potential difference (PD) and short-circuit current (Isc). All tissues were processed for light microscopy. Extent of damage was measured by morphometry. RESULTS: Luminal 0.5 mM NaDOC for 10 min caused R to drop by 43% (n = 4; P < 0.05). Compared with controls 50 ng/ml EGF induced an approximately 30% R increase until the end of the experiments (P < 0.05, n = 4, paired). Ten minutes after injury 50.2 +/- 4% of the mucosa was damaged (n = 6), and after 3 h damage was significantly reduced by EGF (17.2 +/- 3% versus 31.7 +/- 4%, 50 ng/ml EGF versus controls) (P < 0.05, n = 6 per group). Histology showed that EGF stimulated enterocyte migration over the basal lamina. Various doses of bFGF and IGF-1 did not impair restitution when compared with controls. CONCLUSION: In contrast to bFGF and IGF-1, EGF was shown to promote epithelial restitution of human colonic mucosa in vitro.

Colon↗
PubMed1996

Effects of extracellular pH on intracellular pH-regulation and growth in a human colon carcinoma cell-line.

Mechanisms of intracellular pH (pHi) regulation seem to be involved in cellular growth and cell division. Little is known about how extracellular acidosis, known to occur in central regions of solid tumors, or alkaline conditions affect pHi regulation in colonic tumors. pHi changes in the colonic adenocarcinoma cell-line SW-620 were recorded by spectrofluorimetric monitoring of the pH-sensitive, fluorescent dye BCECF, and proliferative activity was assessed by [3H]thymidine uptake. Resting pHi in Hepes-buffered solution was 7.53 +/- 0.01 (n = 36). Both 1 mM amiloride and Na(+)-free solution inhibited pHi recovery from acidification and decreased pHi in resting cells. In HCO3-/CO2-buffered media resting pH1 was 7.42 +/- 0.01 (n = 36). Recovery from acidification was Na(+)-dependent, CI(-)-independent, and only partially blocked by 1 mM amiloride. In the presence of amiloride and 200 microM H2DIDS pHi recovery was completely inhibited. In Na(+)-free solution pHi decreased from 7.44 +/- 0.04 to 7.29 +/- 0.03 (n = 6) and no alkalinization was observed in CI(-)-free medium. Addition of 5 microM tributyltin bromide (an anion/OH-exchange ionophore) caused pHi to decrease from 7.43 +/- 0.05 to 7.17 +/- 0.08 (n = 5). The effects of pH0 on steady-state pHi, pHi recovery from acidification and proliferative activity after 48 h were investigated by changing buffer [CO2] and [HCO3-]. In general, increases in pH0 between 6.7 and 7.4 increased pHi recovery, steady-state pHi and growth rates. In summary, SW-620 cells have a resting pHi > 7.4 at 25 degrees C, which is higher than other intestinal cells. Acid extrusion in physiological bicarbonate media is accomplished by a pHi-sensitive Na+/H+ exchanger and a pHi-insensitive Na(+)-HCO3-cotransporter, both of which are operational in control cells at the resting pHi. No evidence for activity of a CI-/HCO3- exchanger was found in these cells, which could account for the high pHi observed and may explain why the cells continue to grow in acidic tumor environments.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1996

Epidermal growth factor promotes rapid response to epithelial injury in rabbit duodenum in vitro.

BACKGROUND & AIMS: Growth factors are mainly involved in the regulation of intestinal epithelial barrier function. This study investigated the effect of epidermal growth factor (EGF) and insulin-like growth factor 1 (IGF-1) on epithelial restitution of rabbit duodenum in vitro. METHODS: Rabbit duodenal mucosal strips mounted in an Ussing chamber were luminally exposed to 10 mmol/L HCl for 10 minutes and then incubated with buffer alone or luminal buffer containing various concentrations of EGF and IGF-1 for 3 hours. Resistance was calculated from potential difference and short-circuit current. Damage was assessed by morphometry on H&E-stained sections. RESULTS: HCl caused resistance to decrease from 112 +/- 2 to 51 +/- 4 ohms x cm2 10 minutes after injury (n = 6; P < 0.05). Postinjury treatment with 25 or 50 ng/mL luminal EGF for 3 hours stimulated resistance to recover to 94 +/- 3 and 104 +/- 3 ohms x cm2, respectively, vs. 81 +/- 3 omega x cm2 in controls (P < 0.05). Ten minutes after injury, 62% of the mucosa was damaged; 3 hours after injury, damage was reduced to 24% +/- 1.09% and 10% +/- 1.42% in the 25 and 50 ng/mL EGF group, respectively, vs. 38% +/- 0.93% in controls (n = 6 per group). EGF stimulated enterocyte migration. IGF-1 did not impair epithelial restitution. CONCLUSIONS: EGF, but not IGF-1, promoted epithelial restitution of rabbit duodenum in vitro.

Animals↗
PubMed1996

Laminin stimulates rapid epithelial restitution of rabbit duodenal mucosa in vitro.

BACKGROUND: This study investigated the effect of the basal lamina constituents fibronectin, collagen IV, and laminin on epithelial restitution of rabbit duodenum in vitro. METHODS: Rabbit duodenal mucosal sheets were mounted in Ussing chambers, luminally exposed to 10 mM HCI for 10 min, and incubated with buffer or luminal buffer containing 25-100 micrograms/ml of collagen IV, fibronectin, laminin, or polyclonal antisera directed against these proteins (diluted 1:50-1:20) for 3 h. Resistance was calculated from potential difference and short-circuit current. Mucosal damage was assessed by morphometry on hematoxylin- and eosin-stained sections. RESULTS: Acid exposure caused a 40% drop in resistance (119 +/- 5 versus 71 +/- 5 Ohm.cm2 before versus after injury; P < 0.05, n = 6) and mucosal damage of 58 +/- 4% (n = 6). Three hours after injury resistance was 102 +/- 6, 117 +/- 4, and 48 +/- 5 Ohm.cm2 in the control, laminin, and anti-laminin groups, respectively. Furthermore, 36 +/- 2%, 16 +/- 2%, and 64 +/- 5% of the mucosa was damaged in the control, laminin, and anti-laminin groups, respectively, 3 h after injury (P < 0.05 versus controls). Laminin promoted epithelial wound closure by stimulation of enterocyte migration, which was inhibited by anti-laminin. Fibronectin, collagen IV, anti-fibronectin, and anti-collagen IV did not impair restitution. CONCLUSION: Our results show that laminin promotes electrophysiologic restoration and epithelial restitution of rabbit duodenum in vitro. We therefore suggest that laminin plays an important part in the orchestration of epithelial integrity and barrier function.

Animals↗
PubMed1996

Peptic esophageal stricture: is surgery still necessary?

Gastroesophageal reflux disease is frequently complicated by peptic esophageal stricture formation. Treatment of choice over the past 25 years has changed from resection of the stenotic esophagus towards fundoplication, or conservative treatment combined with dilatation. Reports on the long-term results of the clinical course of such patients are still rare. Between 1965 and 1990 200 patients were treated for peptic esophageal stricture by surgery or bougienage with antisecretory medication. Retrospective analysis of the clinical outcome according to the primary therapeutic strategy was performed after a follow-up period of 1.5 to 267 months. 139 patients (group A) primarily received bougienage and medical treatment. After 71 months 36% of the patients were symptom-free, 52% had received further dilatation and 11% had undergone surgery. One fatal complication occurred. 61 patients (group B) underwent primary surgical treatment. Fundoplication was performed in 72% of the cases, resection in 18% and other procedures in 10%. After a median period of 84 months following standard fundoplication (n = 43) 44% were free of symptoms, 39% had received further dilatations and 12% had to be reoperated. Fatal complications occurred in 2 patients (5%). The risk of undergoing surgery after primary dilatation was 16% after 2 years, remaining on this level throughout follow-up time. We conclude that resection of peptic strictures of the esophagus is rarely indicated any more. Treatment of choice consists of primary bougienage combined with antisecretory medication. If conservative treatment fails or patient compliance is low we recommend fundoplication with intraoperative dilatation within the first 2 years after diagnosis of symptomatic stricture.

Adolescent↗
PubMed1994

Intracellular pH regulation of human colonic crypt cells.

In order to investigate the regulation of intracellular pH (pHi) in freshly isolated human colonocytes, we have used a newly developed technique for the rapid isolation and covalent attachment of these cells to glass surfaces and microspectrofluorimetric measurement of the pH-sensitive fluorescence of 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF)-loaded specimens in a perfusion chamber (37 degrees C). In N-2-hydroxyethylpiperazine-N'-2-ethanesulphonic-acid-(HEPES)-buffered Ringer solution (HBS) a baseline pHi of 7.35 +/- 0.03 (mean +/- SD; n = 42) was found for human colonocytes and in HBS, NH4Cl-prepulse-induced intracellular acidification in colonocytes is reversed rapidly by the ubiquitous amiloride-sensitive (1 mmol/l) Na+/H+ exchanger. Switching from HBS to HCO(3-)-buffered solution (BBS) led to a transient intracellular acification (7.29 +/- 0.09), followed by a recovery to a final resting pHi of 7.43 +/- 0.03. One-third of the acid extrusion in BBS is amiloridesensitive; the remaining two-thirds are caused by the dihydroderivative of 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (H2DIDS)-sensitive HCO(3-)-dependent mechanisms. The functional activity of an acid-extruding Na+/HCO3- cotransporter in human colonocytes was observed in response to the reintroduction of Na+ into amiloride-containing Na+/Cl(-)-free BBS. In addition, the mechanism leading to alkalinization (7.56 +/- 0.05) in Cl(-)-free BBS was identified as Na(+)-dependent Cl-/HCO3- exchange, by its H2DIDS sensitivity and the specific requirement for Cl- and Na+. The intrinsic buffering capacity (beta i) of the human colonocytes was calculated from pH changes induced by sequential NH4Cl-loading steps during blockage of acid/base transporters.(ABSTRACT TRUNCATED AT 250 WORDS)

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1992

A decade of oral anticoagulant treatment to maintain autologous vein grafts for femoropopliteal atherosclerosis.

To determine whether long-term oral anticoagulant treatment was effective in improving graft performance and preventing major amputation following vein bypass surgery for femoropopliteal atherosclerosis, a clinical trial was conducted in one single center and continued during 10 years. After 130 patients had electively received a femoropopliteal vein graft, they were randomly assigned to a therapy group (treatment with phenprocoumon [n = 66]) or to a control group (n = 64) that remained without any anticoagulant treatment. Primary end points of the study were graft reocclusion and limb loss. The median durations of primary patency and limb salvage were significantly longer for treated patients than that for controls. In addition, survival in the therapy group was longer. Following autologous vein bypass surgery in the treated group, the results were superior in terms of graft patency, limb salvage, and survival.

Administration, Oral↗
PubMed1992

pHi dependence of Na-H exchange and H delivery in IEC-6 cells.

The intracellular pH (pHi) dependencies of the Na-H exchanger and also of unidentified acid-loading processes ("H delivery") in IEC-6, a rat intestinal crypt cell line, were determined using microspectrofluorimetry of the pH-sensitive dye 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein on groups of cells grown on glass cover slips mounted in a perfusion chamber in HCO3-free solutions (to inactivate Cl-HCO3 exchange and Na-HCO3 cotransport). Na-H exchange and H delivery rates were measured using two methods. 1) Cells were acid loaded with NH4Cl, and rates of pHi recovery and acidification were measured just before and then just after adding amiloride at various times during the recovery. Multiplying rates of pHi recovery times the intrinsic buffer capacity (beta i) yielded net H efflux rates, rates of pHi decrease (during amiloride treatment) times beta i yielded H delivery rates, and Na-H exchange equals net H efflux plus H delivery. 2) In control cells, time courses of amiloride-induced pHi decreases (from 7.36 to 6.65) and of pHi recovery following amiloride removal (from 6.65 to 7.49) were curve fit by computer; rates of pHi decrease and recovery were calculated; and H delivery, net H efflux, and Na-H exchange were then calculated at the different pHi as above. H delivery and Na-H exchange were both pHi dependent, but in the opposite directions. H delivery was 2-7 mM/min at the control pHi, decreasing to zero around pHi 6.6. Na-H exchange was also equal to 2-7 mM/min at the control pHi, and this increased as pHi decreased; at pHi 6.6, Na-H exchange was 20-35 mM/min.(ABSTRACT TRUNCATED AT 250 WORDS)

Ammonia↗
PubMed1992

[Multivisceral and extended resection in tumor surgery--esophageal cancer].

Extended resections are strategies in the surgical treatment of cancer which provide large oncological safety margins: these are of particular relevance in the neck in view of the close anatomical relation of the major cervical organs. In the region of the distal esophagus, extended resections may be a reasonable alternative to conservative approaches even when only intended as a palliative treatment. The removal of metastases does not influence the outcome in patients with esophageal carcinoma, in contrast to simultaneous surgery of other malignancies.

Esophageal Neoplasms↗