Clinical trial: a multicentre, randomized, double-blind, placebo-controlled, dose-finding, phase II study of subcutaneous interferon-beta-la in moderately active ulcerative colitis.

BACKGROUND: Ulcerative colitis (UC) pathophysiology is characterized by an imbalance between pro- and anti-inflammatory cytokines. Interferon (IFN)-beta-1a has potent immunoregulatory properties, including stimulation of host defence mechanisms and thus represents a potential treatment. AIM: To extend pilot data and identify a suitable dose of IFN-beta-1a to achieve endoscopically confirmed remission (ECR) in patients with moderately active UC and to evaluate safety. METHODS: In this multicentre, double-blind, placebo-controlled trial, adults with moderately active UC were randomized to IFN-beta-1a 44 or 66 microg, or placebo, subcutaneously three times weekly for 8 weeks, with a 4-week follow-up. RESULTS: Endoscopically-confirmed remission was observed in 23.4% [95% confidence interval (CI): 13.8-35.7] of placebo patients, 29.2% (95% CI: 18.6-41.8) of the IFN-beta-la 44 microg group and 20.0% (950% CI: 11.1-31.8) of the 66 microg group (P = 0.45). Improvements with IFN-beta-1a 44 microg were greater than with placebo for most secondary efficacy outcomes, although significance was not achieved. Placebo response rates were higher than expected from previous trials. Adverse events were similar to the known safety profile of IFN treatment. CONCLUSIONS: Interferon-beta-1a was generally well tolerated at the doses tested, but a significant therapeutic benefit in patients with UC was not observed.

Apoprotein B in fasting and postprandial human jejunal mucosa.

We tested whether apoprotein B is present in fasting and postprandial human duodenojejunal mucosa because lipoprotein-like particles are visualized by electron microscopy within the smooth endoplasmic reticulum and the Golgi cisternae of these absorptive cells. Duodenojejunal biopsies from normal volunteers were incubated in citrate buffer and were shaken in 1% EDTA so that absorptive cells could be freed from underlying tissue. Apoprotein B was determined by double-antibody radioimmunoassay in homogenates of absorptive cells. The preparations of absorptive cells were shown to be uncontaminated by plasma lipoproteins; they did not contain any albumin by immunodiffusion able to detect 2 mug/ml. They adsorbed less than 0.1% of 125I-low density lipoprotein which was added to the citrate buffer. Cell preparations from suction biopsies of human rectum contained no detectable apoprotein B. Duodenojejunal absorptive cells from 22 fasting subjects contained 3.2 +/- 0.5 mug of apoprotein B per 100 mg (wet wt) of biopsies or 1.3 mug of apoprotein B per mg of total cell protein. The amount of apoprotein B per milligram of cell protein fell to 0.3 mug in 14 of these individuals whose mucosa was also sampled 45 min after instilling fat intraduodenally. These experiments provide immunochemical evidence that human duodenojejunal absorptive cells contain apoprotein B. This technique should be valuable for studying the physiology of intestinal lipoproteins in absorption and in patients with hyperlipidemia.

The isolation and purification of human peripheral blood monocytes in cell suspension.

A simple method for the isolation of human peripheral blood monocytes in cell suspension is described. The method is based on the adherence and detachment characteristics of monocytes during their in vitro cultivation and does not require any gradient centrifugation or modulating substances. The mean percentage of monocytes recovered from different donors was 81.9% (60-100%) of the original phagocytic cells found in the peripheral blood of the tested donors and the cell suspensions obtained consisted of more than 95% of monocytes. The monocytes isolated in suspensions show high activity in various monocyte functions tested.

Development of macrophage and granulocyte colonies from human peripheral blood.

The presence of macrophage and granulocyte progenitor cells in the human peripheral blood enabled the establishment of colonies from this accessible tissue and obviated the need for bone marrow to achieve this task. We have developed a method of obtaining reproducible growth of macrophage/granulocyte colonies from human peripheral blood. Colonies of macrophages and granulocytes were obtained by plating peripheral blood mononuclear cells (PBM) in methylcellulose containing medium in the presence of medium conditioned by nonstimulated PBM (CM). At early stages of colony growth both macrophage and granulocyte colonies were detected while following 20-25 days in culture all colonies tested revealed monocyte-macrophage morphology. To obtain higher numbers of colonies, we tested different cell sources, different CM preparations and the effect of steroid hormones on colony development. We found that the mononuclear cells obtained from cord blood (CB) or from some patients with inflammatory bowel disease yielded much higher numbers of colonies than PBM from normal individuals. Colony development from these two sources did not depend on an external source of colony stimulating factor (CSF) but was augmented as a result of CSF supplementation. CM obtained from CB mononuclear cells as well as supernatants from some human monoblastic cell lines were similar in their CSF activity to CM from normal PBM and made possible the development of macrophage/granulocyte colonies. Higher numbers of colonies were induced by including physiological concentrations of estradiol in the culture medium, in the absence of external sources of CSF. The system described above enabled the analysis of cloned macrophages and their circulating progenitor cells as well as the assay of different preparations of CSF.

The effect of ketotifen on nitric oxide synthase activity.

1. We studied the effect of ketotifen, a second generation H1-receptor antagonist on nitric oxide synthase (NOS) activity in colonic mucosa and in renal tissues, and on rat renal haemodynamics in vivo. 2. Ketotifen (100 micrograms ml-1) increased human colonic NOS activity from 3.7 +/- 0.6 to 14.5 +/- 1.3 nmol g-1 min-1 (P < 0.005, ANOVA). In rat renal cortical and medullary tissues ketotifen increased NOS activity by 55% and 86%, respectively (P < 0.001). The stimulation of NOS activity was attenuated by NADPH deletion and by the addition of N omega nitro-L-arginine methyl ester (L-NAME) or aminoguanidine, but not by [Ca2+] deprivation. NOS activity was unaffected by two other H1-antagonists, diphenhydramine and astemizole, or by the structurally related cyproheptadine. Renal cortical NOS activity was also significantly stimulated 90 min after intravenous administration of ketotifen to anaesthetized rats. 3. Ketotifen administration to anaesthetized rats induced modest declines in blood pressure and reduced total renal, cortical and outer medullary vascular resistance. This is in contrast to diphenhydramine, which did not induce renal vasodilatation. 4. We conclude that ketotifen stimulates NOS activity by mechanisms other than H1-receptor antagonism. The association of this effect with therapeutic characteristics of ketotifen and the clinical implications of these findings are yet to be defined.

Deferiprone, an oral iron chelator, ameliorates experimental colitis and gastric ulceration in rats.

Iron is pivotal is producing tissue-damaging reactive oxygen metabolites. Our aim is to determine the antiinflammatory activity of deferiprone, an oral iron chelator, in experimental colitis and gastritis. Colitis was induced by intraceccal administration of 2 ml 5% acetic acid or by intracolonic administration of 0.1 ml 3% iodoacetamide, with or without cotreatment with deferiprone. Gastritis was induced by intragastric administration of ethanol or hydrochloric acid (HCl) and by subcutaneous injection of indomethacin, with and without deferiprone. Rats were killed 24 hours after acetic acid and iodoacetamide, 30 minutes after ethanol, one hour after HCl, and three hours after indomethacin administration. The colon or stomach was isolated, macroscopic damage was measured, and mucosal samples were obtained for determination of eicosanoid generation, myeloperoxidase (MPO), and nitric oxide synthase (NOS) activities. Deferiprone decreased iodoacetamide and acetic acid-induced macroscopic colonic damage by 67% and 69%, respectively, and macroscopic gastric damage by 91%, 68%, and 46% induced by ethanol, HCl, and indomethacin, respectively. The effect of deferiprone was accompanied by significant decrease in colonic and gastric, MPO and NOS activities, and colonic prostaglandin E2 (PGE2) generation, in acetic acid, ethanol, and indomethacin models, whereas in the iodoacetamide and HCl models attenuation of the decrease in PGE2 generation was seen. Deferiprone is protective in experimental colitis and gastritis, probably due to decreased production of iron-dependent oxygen-free radicals. Oral iron chelators may constitute a novel approach to ameliorate gastrointestinal inflammatory disorders.

The association between smoking and inflammatory bowel disease among israeli jewish patients.

: Our objective was to assess the association between smoking status before the onset of disease and inflammatory bowel disease (IBD) in Israeli Jewish patients through a case-control study conducted at the Hadassah University Hospital in Jerusalem, Israel, and a periodic health examination center. The cases included 71 patients with ulcerative colitis (UC) and 91 with Crohn's disease. Patients younger than 18 years at onset of disease were excluded. The controls included 162 healthy, asymptomatic individuals, matched with the patients with IBD by age at onset of disease and gender. Fewer patients with UC were current smokers (9.8%) than were controls (25.0%; p < 0.05). More patients with UC were former smokers (21.0%) than were controls (14.0%; p < 0.05). The odds ratio for UC in smokers compared with ex-smokers was 0.26 (95% CI, 0.13-0.53), and for smokers compared with never-smokers was 0.34 (95% CI, 0.21-0.54). No significant associations were found between smoking status and Crohn's disease. The results for UC are consistent with most reports and probably reflect a true association between smoking status and disease. The lack of association between smoking and Crohn's disease is in agreement with a previous Israeli study but differs from other reports. This may reflect a genetic predisposition among Jews that obscures the effects of smoking.

Sulphydryl blocker-induced rat colitis is ameliorated by intravenous injection of antibody to colonic surfactant-like particle.

A rat model of experimental colitis and jejunitis induced by iodoacetamide (IA), a sulphydryl blocker is accompanied by increased leukotriene, prostaglandin E2 (PGE2) generation, and nitric oxide synthase (NOS) activity. Rat small intestinal and colonic surfactant-like particles (SLP) that accumulate on the apical surface of mucosal cells have been identified and specific antibodies to them have been produced. The aim of this study was to evaluate a possible role of SLP in IA-induced colitis and jejunitis. Inflammation was induced in Sprague-Dawley rats either by intracolonic administration of 3% IA (0.1 ml) or by intrajejunal administration of 2% IA (0.1 ml). Antisera raised against either colonic SLP, pulmonary SP-A (a major protein associated with colonic SLP), or small intestinal SLP were injected into the tail vein of rats 48 h before, simultaneous with, or 24 h after IA administration. Rats were killed 2 or 10 days after IA was given, their colon or small intestine was isolated and rinsed, and a segment of colon (10 cm) or small bowel (30 cm) was weighed and processed for microscopy, NOS and myeloperoxidase (MPO) activities, and PGE2 generation. Intracolonic or jejunal IA resulted after 48 h in extensive macroscopic and microscopic damage, accompanied by increased segmental weight, MPO and NOS activity, and PGE2 generation. Colonic SLP antibody administration, either 48 h before or at the time of damage induction, significantly decreased macroscopic as well as microscopic damage, segmental weight, MPO activity, and PGE2 generation, but had no effect on NOS activity. Neither control sera nor antisera against SP-A had any protective effect, nor did injection of anti-colonic SLP antisera given 24 h after IA. Small bowel SLP antibody offered no protection against IA jejunitis. IA-induced colitis but not jejunitis is ameliorated by intravenous injection of SLP antibody by a mechanism yet to be determined. These data provide further evidence of a physiologic role for gastrointestinal SLP.

Mesalazine 4 g daily given as prolonged-release granules twice daily and four times daily is at least as effective as prolonged-release tablets four times daily in patients with ulcerative colitis.

BACKGROUND: High doses of mesalazine usually result in an inconvenient dosage schedule and reduced compliance. The goal of this trial was to compare the effects of mesalazine 4 g daily given as prolonged-release granules in packets of 1 g with that of prolonged-release tablets of 0.5 g. METHODS: Two hundred twenty-seven patients with mild-to-moderate ulcerative colitis were randomized to treatment with two packets twice daily (Gr-b.i.d.), 1 packet four times daily (Gr-q.i.d.) or 2 tablets four times daily (Ta-q.i.d.) for 8 weeks. A disease activity index (ulcerative colitis disease activity index: UC-DAI) was calculated, and the granules were defined as noninferior to the tablets if the lower limit of the 95% CI for the differences was more than -1 UC-DAI score unit. RESULTS: Noninferiority of the granules compared with the tablets was demonstrated. The mean improvement in the UC-DAI in the treatment groups Gr-b.i.d., Gr-q.i.d., and Ta-q.i.d. were 3.2, 2.9, and 2.4, respectively; the proportion of complete responders in the three groups 39%, 37%, and 31%, respectively. There were no differences in side effects. CONCLUSION: Mesalazine 4 g daily given as prolonged-release granules twice and four times daily is at least as effective as prolonged-release tablets four times daily in patients with mild to moderate ulcerative colitis. The patients preferred the twice daily dosing.

A simple classification of Crohn's disease: report of the Working Party for the World Congresses of Gastroenterology, Vienna 1998.

Crohn's disease is a heterogeneous entity. Previous attempts of classification have been based primarily on anatomic location and behavior of disease. However, no uniform definition of patient subgroups has yet achieved broad acceptance. The aim of this international Working Party was to develop a simple classification of Crohn's disease based on objective variables. Eight outcome-related variables relevant to Crohn's disease were identified and stepwise evaluated in 413 consecutive cases, a database survey, and by clinical considerations. Allocation of variables was conducted with well-defined Crohn's disease populations from Europe and North America. Cross-table analyses were performed by chi-square testing. Three variables were finally elected: Age at Diagnosis [below 40 years (A1), equal to or above 40 years (A2)], Location [terminal ileum (L1), colon (L2), ileocolon (L3), upper gastrointestinal (L4)], and Behavior [nonstricturing nonpenetrating (B1), stricturing (B2), penetrating (B3)]. The allocation of patients to these 24 subgroups proved feasible and resulted in specific disease clusters. Cross-table analyses revealed associations between Age at Diagnosis and Location, and between Behavior and Location (all p < 0.001). The Vienna classification of Crohn's disease provides distinct definitions to categorize Crohn's patients into 24 subgroups. Operational guidelines should be used for the characterization of patients in clinical trials as well as for correlation of particular phenotypes with putative biologic markers or environmental factors.

The role of H2-receptor antagonists in the prevention of NSAID-induced gastrointestinal damage.

Non-steroidal anti-inflammatory drugs (NSAIDs) induce gastric and duodenal damage in animals and humans. The possible protection afforded by cimetidine against acute and short-term NSAID-induced mucosal damage was evaluated in five studies. Cimetidine 200 mg once daily and 400 mg once daily was found to protect the gastric mucosa against damage induced by a single dose of aspirin 1300 mg; this protection was found to be independent of gastric acid secretion. Cimetidine 200 mg q.d.s. was found to protect the stomach and duodenum against damage induced by 14 days' treatment with aspirin 650 mg q.d.s. Duodenal and gastric damage induced during a 7-day treatment period with naproxen 500 mg b.d. was prevented by cimetidine 400 mg b.d.; this dose of cimetidine also provided significant duodenal protection against damage induced by 1 week of therapy with indomethacin 50 mg t.d.s. There is no correlation between upper gastrointestinal symptoms, or between mucosal prostanoids, and the presence or absence of mucosal damage. Cimetidine is therefore effective in the prevention of mucosal damage induced by short-term treatment with NSAIDs.

Efficacy of misoprostol and ranitidine in the prevention of duodenal ulcer relapse and its correlation with endogenous gastric prostanoid synthesis.

We determined endogenous gastric prostaglandin synthesis and its correlation with the prevention of duodenal ulcer relapse by misoprostol and ranitidine. Sixty-one patients with recent endoscopically healed duodenal ulcer were randomly allocated in a double-blind fashion for one year of treatment with misoprostol 400 micrograms nocte, ranitidine 150 mg nocte or placebo. Patients were followed every two months. Endoscopy was repeated at six and 12 months or beforehand, if relapse was suspected. Antral and fundic biopsies, 3-4 from each region, were obtained at each endoscopy for determination of prostaglandin synthesis. During the one year of treatment, 11 out of the 12 placebo treated patients flared up, as opposed to 10 out of 25 and four out of 24 misoprostol and ranitidine treated patients, respectively. The difference between all treatment groups was significant (P less than 0.0001). In all subjects who flared up, pretrial endogenous antral and fundic prostaglandin E2 synthesis were not different from their respective synthesis in those who did not relapse.

The role of platelet activating factor [correction of actor] in acute gastric injury and its protection by sucralfate.

Platelet activating factor, a potent inflammatory mediator, has been reported to induce gastrointestinal damage, whereas its inhibition or antagonism is associated with mucosal protection. The aim of the present study was to elucidate the association between acute experimental gastric damage and mucosal platelet activating factor generation in the rat, and to evaluate the protective effect of sucralfate in relation to mucosal platelet activating factor formation. Gastric damage in the rat was induced by either subcutaneous injection of indomethacin 30 mg/kg or intragastric administration of aspirin 100 mg/kg, hydrochloric acid 0.6 N, taurocholate 30 mM, ethanol 96%, or sodium chloride 25%. All agents induced a significant increase in mucosal platelet activating factor levels concomitantly with induction of mucosal damage. Pretreatment with sucralfate 150 mg/rat provided a significant macroscopic and microscopic mucosal protection in all experimental models. This protection was associated with a significant decrease in mucosal platelet activating factor level in the hydrochloric acid, taurocholate, ethanol and hyperosmolar sodium chloride treated rats, whereas it remained unchanged in the aspirin and indomethacin treated rats. The data imply that platelet activating factor may have a limited role in the pathogenesis of indomethacin or aspirin induced damage, where other mechanisms such as cyclooxygenase inhibition dominate. In the damage induced by topical strong irritants, platelet activating factor may have a major pathogenetic role.

No correlation between indomethacin-induced gastroduodenal damage and inhibition of gastric prostanoid synthesis.

The effect of 1 week of treatment with indomethacin 150 mg/day on human gastric prostanoid synthesis was correlated with its effect on gastric and duodenal mucosa. Before and following 1 week of treatment, endoscopic appearance of the mucosa was evaluated and scored. Following 1 week of treatment with indomethacin, antral PGE2 and 6-keto-PGF1 alpha were significantly lower than in normal subjects, but similar in patients with significant or with no mucosal damage. Co-treatment with ranitidine 150 mg b.d. or with cimetidine 400 mg b.d. reduced the mean mucosal damage score but did not affect gastric prostanoid synthesis, which was similar irrespective of the presence or absence of mucosal damage. It is therefore suggested that there is no correlation between indomethacin-induced inhibition of gastric prostanoid synthesis and its induction of mucosal damage.

Heparin and low-molecular-weight heparin (enoxaparin) significantly ameliorate experimental colitis in rats.

BACKGROUND AND AIMS: The anticoagulants, unfractionated heparin and low-molecular-weight heparin, demonstrated anti-inflammatory effects in animal models and in humans. Because of its dual effects, high-dose heparin was proposed as a therapeutic modality for ulcerative colitis. We investigated whether a low dose of low-molecular-weight heparin-enoxaparin (Clexane, Rhône-Poulenc Rorer, France)-ameliorates the inflammatory response in two models of experimental colitis. METHODS: Colitis was induced in rats by intrarectal administration of dinitrobenzene sulphonic acid. Enoxaparin (40, 80 and 200 microg/kg) or unfractionated heparin (100, 200 and 400 U/kg) were administered subcutaneously immediately after the induction of damage. Enoxaparin, 80 microg/kg, was also administered after induction of colitis by intrarectal administration of iodoacetamide. Rats were sacrificed 1, 3 or 7 days after induction of injury. Colonic damage was assessed macroscopically and histologically. Mucosal prostaglandin E2 generation, myeloperoxidase and nitric oxide synthase activities and tumour necrosis factor-alpha levels in blood were determined. RESULTS: Enoxaparin and heparin significantly ameliorated the severity of dinitrobenzene sulphonic acid- and iodoacetamide-induced colitis as demonstrated by a decrease in mucosal lesion area, colonic weight and mucosal myeloperoxidase and nitric oxide synthase activities. The dose-response curve had a bell-shaped configuration: enoxaparin, 80 microg/kg, and unfractionated heparin, 200 U/kg, were the optimal doses. CONCLUSIONS: Low-dose enoxaparin and unfractionated heparin ameliorate the severity of experimental colitis. This effect is related to their anti-inflammatory rather than anticoagulant properties.

Mesalazine (Mesasal/Claversal) 1.5 g b.d. vs. placebo in the maintenance of remission of patients with Crohn's disease.

UNLABELLED: INVESTIGATORS: This multicentre study was conducted by 29 principal investigators in 11 countries. AIMS: To compare the safety and efficacy of oral mesalazine (Mesasal/Claversal, 5-ASA) 1.5 g b.d. in comparison with placebo in the maintenance of remission in 286 patients with Crohn's disease. MATERIALS AND METHODS: Patients had to score less than 150 in their Crohn's Disease Activity Index (CDAI), and had to have had one period of clinical activity (CDAI > 150) within 18 months of the study start. Patients were randomized to receive 5-ASA 1.5 g b.d. daily or matching placebo for 12 months. Study visits were scheduled for months 1, 3, 6, 9 and 12, or when symptoms suggested a relapse of the disease. Relapse was defined as a CDAI score greater than 150, with at least a 60-point increase from the baseline index score. None of the patients used glucocorticoids or immunosuppressants during the trial. RESULTS: In the first group, 207 patients with Crohn's colitis or ileocolitis were randomized: there were 101 females and 106 males, in age range 18-71 years. A total of 106 patients (51 in the 5-ASA group and 55 in the placebo group) were withdrawn from the study due to adverse events, insufficient therapeutic effect, or for other reasons. This left 101 patients (51 in the 5-ASA group and 50 in the placebo group) who completed the 12-month trial. In the second group, 79 patients with Crohn's ileitis were randomized to treatment. There were 53 females and 26 males, age range 18-66 years. A total of 41 patients (19 in the 5-ASA group and 22 in the placebo group) were withdrawn from the study. This left 38 patients (17 in the 5-ASA group and 21 in the placebo group) who completed the 12-month trial. The primary efficacy variable was the CDAI. A protocol-eligible analysis and an intent-to-treat analysis were performed. No statistical differences were noted between the two analyses. In patients with Crohn's colitis or ileocolitis, or in those with ileitis, no statistically significant differences were noted with respect to the relapse rates between the 5-ASA and the placebo treatment groups. Adverse events in the gastrointestinal system were the most frequently reported in both treatment groups. Many of the events such as diarrhoea or abdominal pain are symptoms of Crohn's disease. The majority of the events reported were mild or moderate in severity. In neither study was the prevalence of adverse events or the proportion of drop-outs different between patients in the treatment or in the placebo groups. The site of the Crohn's disease had no effect on the frequency of adverse events. CONCLUSION: The relapse rates of Crohn's disease were similar for up to 12 months in both the 5-ASA 1.5 g b.d. and the placebo treatment groups.

Endoscopic insertion of endoprostheses in the treatment of postoperative cutaneous biliary fistula.

We report a case in which a large, postoperative, biliary cutaneous fistula was successfully treated by means of endoscopic insertion of two endoprostheses into the common bile duct. Twenty-four hours after the procedure, bile flow from the cutaneous fistula ceased completely. The endoprostheses were removed after 6 weeks, and no evidence of leak from the biliary tract was seen on a retrograde cholangiogram. For the treatment of postoperative biliary leaks, insertion of endoprostheses is a good and safe alternative to surgery.

Apolipoprotein A-I synthesis and secretion by cultured human intestinal mucosa.

Cultured human duodenojejunal mucosa was used to study the synthesis and secretion of apoprotein A-I (apoA-I), the major protein constituent of plasma high density lipoproteins. ApoA-I, measured by radioimmunoassay, was secreted continuously into the culture medium over a period of 24 hr. The highest rate was found in the first two hours (34.6 +/- 3.0 ng/mg tissue X hr, mean +/- SE, n = 24). Secretion rate decreased with incubation time, while changes of culture medium increased the rate. ApoA-I secretion was enhanced three- to fourfold by micellar lipid solution and was inhibited by puromycin, ApoA-I synthesis was confirmed by incorporation of 14C-leucine into this apoprotein. The specific activity of apoA-I in medium ultracentrifugal fractions (d less than 1.019 and d = 1.063--1.21 g/ml) was calculated from quantitative data obtained by radioimmunoassay and radioassay of apoA-I separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and found to be about 12 mCi/mmol. These observations indicate that cultured human intestinal mucosa is capable of secreting newly synthesized apoA-I. Organ culture may thus serve as a tool for studying the regulating mechanisms for the synthesis and secretion of this important apoprotein.

Longitudinal prostaglandin E(2) generation in various organs during evolution of experimental portal hypertension.

It has been suggested that the arteriolar vasodilatation and hyperdynamic circulation observed in rats with partial portal vein ligation (PPVL) is caused by increased splanchnic and systemic delivery of vasodilator substances. The aims of our study were to determine organ-specific generation of prostaglandin E(2) (PGE(2)) in rats with PPVL during the evolution of portal hypertension. Rats with PPVL and sham-operated (S) rats were studied in the first, third, fourth and 14th postoperative days. They were anesthetized and splenic pulp pressure and blood pressure were measured. Spleen, colon and lungs were removed and the splenic, pulmonary and mucosal colonic PGE(2) were determined. All PPVL rats developed sequential hemodynamic changes compatible with evolving portal hypertension. Splenic pulp pressure was higher in PPVL rats compared with S rats during all days of the study. Within the group of PPVL the splenic pulp pressure was higher in the first postoperative day and decreased in the ensuing days. No changes in splenic and colonic PGE(2) generation were noted during the study period. Pulmonary PGE(2) generation increased significantly in the first postoperative day in PPVL rats compared with S rats. However, similar increase was observed on the third postoperative day in S rats. PGE(2) probably has no role in splanchnic hemodynamic changes during evolution of portal hypertension. Pulmonary PGE(2) generation may increase as a response to increased portal pressure, or to abdominal surgery.

Effect of nufenoxole on human colonic prostanoid synthesis, Na-K-ATPase and adenylate cyclase activities.

To elucidate the possible mechanism whereby nufenoxole exerts its anti-diarrheal activity, its effects on human colonic prostanoid synthesis and on Na-K-ATPase and adenylate cyclase activity were determined. Colonic Na-K-ATPase activity was significantly different in the absence and presence of nufenoxole (50 ng/ml), 1.73 +/- 0.18 and 0.99 +/- 0.17 (x +/- S.E.; N = 18) mumol Pi/mg protein per h respectively. Nufenoxole (50-800 ng/ml) did not affect basal NaF-, VIP- or PGE2-stimulated colonic adenylate cyclase activity. 6-keto PGF1 alpha and TXB2 synthesis by cultured colonic mucosa was also not affected by nufenoxole (50-800 ng/ml). Nufenoxole (800 ng/ml) induced slight inhibition of PGE2 synthesis by cultured colonic mucosa. The results obtained do not suggest that the anti-diarrheal effects of nufenoxole are related to its in vitro effects on colonic prostanoid synthesis or adenylate cyclase activity. Inhibition of colonic Na-K-ATPase activity by nufenoxole also does not explain its anti-diarrheal effects. Further studies on nufenoxole effects on the respective jejunal enzyme systems and in human subjects treated with the drug may reveal its mechanism of action.