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New arylpiperazine derivatives as antagonists of the human cloned 5-HT(4) receptor isoforms.

New derivatives of arylpiperazine 9 were designed from ML 10302, a potent 5-HT(4) receptor agonist in the gastrointestinal system. Compounds were synthesized by condensation of a number of available arylpiperazines or heteroarylpiperazines with 2-bromoethyl 4-amino-5-chloro-2-methoxybenzoate. They were evaluated in binding assays on the recently cloned human 5-HT(4(e)) isoform stably expressed in C6 glial cells with [(3)H]GR 113808 as the radioligand. The affinity values (K(i)) depended upon the substituent on the aromatic ring. A chlorine atom produced a marked drop in activity (K(i) > 100 nM), while a m-methoxy group gave a compound with nanomolar affinity (K(i) = 3 nM). The most potent compounds were the heterocyclic derivatives with pyrimidine, pyrazine, pyridazine, or pyridine moieties (compounds 9r, 9t, 9u, 9x, respectively). K(i) values for 9a and 9r were determined for the 5-HT(4(a)), 5-HT(4(b)), 5-HT(4(c)), and 5-HT(4(d)) receptor isoforms transiently expressed in COS cells. The results indicated that the compounds were not selective. They produced an inhibition of the 5-HT-stimulated cyclic AMP synthesis in the C6 glial cells stably expressing the 5-HT(4(e)) receptor and shifted the 5-HT concentration-effect curve on adenylyl cyclase activity with pK(D) values of 7.44 and 8.47, respectively. In isolated human atrial myocytes, 9r antagonized the stimulatory effect of 5-HT on the L-type calcium current (I(Ca)) with a K(D) value of 0.7 nM.

4-Aminobenzoic Acid↗

The zero-stress state of the gastrointestinal tract: biomechanical and functional implications.

The stresses and strains that remain in an organ when the external load is removed (the no-load state) are called residual stresses and strains. They can be relieved by cutting up the organ to obtain the zero-stress configuration. This phenomenon was demonstrated more than 15 years ago in cardiovascular research but until recently it was not realized by the gastrointestinal research community. The function of the gastrointestinal tract is to propel food by peristaltic motion, which is a result of the interaction of the tissue forces in the wall and the hydrodynamic forces in the food bolus. To understand the tissue forces, it is necessary to know the stress-strain relationships of the tissues that must be measured in reference to the zero-stress state. It has become clear that the zero-stress configuration of the gastrointestinal tract is very different from that of the no-load condition and that the zero-stress state is sensitive to structural and mechanical remodeling. The purpose of this review is to describe the basic theory and experiments of residual stress and to explore its physiological and pathophysiological implications in the gastrointestinal system.

Animals↗

Smoking and the pathogenesis of gastroduodenal ulcer--recent mechanistic update.

Peptic ulcer is a common disorder of gastrointestinal system and its pathogenesis is multifactorial, where smoking and nicotine have significant adverse effects. Smoking and chronic nicotine treatment stimulate basal acid output which is more pronounced in the smokers having duodenal ulcer. This increased gastric acid secretion is mediated through the stimulation of H2-receptor by histamine released after mast cell degranulation and due to the increase of the functional parietal cell volume or secretory capacity in smokers. Smoking and nicotine stimulate pepsinogen secretion also by increasing chief cell number or with an enhancement of their secretory capacity. Long-term nicotine treatment in rats also significantly decreases total mucus neck cell population and neck-cell mucus volume. Smoking also increases bile salt reflux rate and gastric bile salt concentration thereby increasing duodenogastric reflux that raises the risk of gastric ulcer in smokers. Smoking and nicotine not only induce ulceration, but they also potentiate ulceration caused by H. pylori, alcohol, nonsteroidal anti-inflammatory drugs or cold restrain stress. Polymorphonuclear neutrophils (PMN) play an important role in ulcerogenesis through oxidative damage of the mucosa by increasing the generation of reactive oxygen intermediates (ROI), which is potentiated by nicotine and smoking. Nicotine by a cAMP-protein kinase A signaling system elevates the endogenous vasopressin level, which plays an aggressive role in the development of gastroduodenal lesions. Smoking increases production of platelet activating factor (PAF) and endothelin, which are potent gastric ulcerogens. Cigarette smoking and nicotine reduce the level of circulating epidermal growth factor (EGF) and decrease the secretion of EGF from the salivary gland, which are necessary for gastric mucosal cell renewal. Nicotine also decreases prostaglandin generation in the gastric mucosa of smokers, thereby making the mucosa susceptible to ulceration. ROI generation and ROI-mediated gastric mucosal cell apoptosis are also considered to be important mechanism for aggravation of ulcer by cigarette smoke or nicotine. Both smoking and nicotine reduce angiogenesis in the gastric mucosa through inhibition of nitric oxide synthesis thereby arresting cell renewal process. Smoking or smoke extract impairs both spontaneous and drug-induced healing of ulcer. Smoke extract also inhibits gastric mucosal cell proliferation by reducing ornithine decarboxylase activity, which synthesises growth-promoting polyamines. It is concluded that gastric mucosal integrity is maintained by an interplay of some aggressive and defensive factors controlling apoptotic cell death and cell proliferation and smoking potentiates ulcer by disturbing this balance.

Animals↗

Phase I trial of orally administered CEP-701, a novel neurotrophin receptor-linked tyrosine kinase inhibitor.

PURPOSE: A phase I clinical trial in patients with advanced carcinomas was conducted using the orally available neurotrophin receptor-linked tyrosine kinase receptor inhibitor, CEP-701. The objectives were to determine the maximum tolerated dose (MTD), dose-limiting toxicities, and pharmacokinetic profile of this orally administered agent. PATIENTS AND METHODS: A total of 30 patients were accrued to receive escalating BID doses of CEP-701 in cycles lasting 28 days. Between 3 and 6 patients were enrolled at each dose level. Once the MTD was determined, nine de novo patients were recruited to receive that level of drug. Pharmacokinetic studies were performed after the first dose, with additional sampling to assess intraindividual variability. RESULTS: The dosages ranged from 5 mg BID to 160 mg BID. While the criteria for MTD were not met at the dose levels administered, DLTs were observed at 80 and 120 mg BID. Treatment related adverse events, especially of the gastrointestinal system, made CEP-701 poorly tolerated at dosages above 40 mg BID. While CEP-701 did not produce an objective tumor response in any patient, 7 of the 30 patients received treatment for 3 months or more, including 3 who were on study with stable disease for more than 6 months. Orally administered CEP-701 was rapidly absorbed, with a mean t(max) between 1 and 3 hours. At higher dose levels, serum drug levels showed greater than dose-proportional increases by Day 28 versus Day 1. CONCLUSION: CEP-701 40 mg BID was well tolerated by patients with advanced malignancy and is the recommended dose level for planned phase II trials. Further study is necessary to determine the clinical efficacy of this novel new chemotherapeutic agent.

Administration, Oral↗

[Surgery of pancreatic carcinoma].

Pancreatic cancer is the third leading neoplasm of the gastrointestinal system and has a dismal prognosis. The majority of patients are no more suitable for resection at time of diagnosis due to early development of distant metastases or major infiltration of adjacent structures. However, due to the resistance of pancreatic cancer against radiation and chemotherapy, radical resection represents the only therapy with a potential for cure. For the surgical treatment of pancreatic head cancer, the classical Whipple operation is still the standard procedure but during the last two decades, pylorus-preserving pancreatoduodenectomy has been evolved as a more conservative procedure in order to omit the consequences of partial gastrectomy. For cancer of the pancreatic body and tail, distal pancreatectomy or total pancreatectomy represent the current standard treatment. More radical methods like regional pancreatectomy and resection with extended lymph node dissection have failed so far to demonstrate any improvements in long-term survival compared to the standard types of resection. To further improve the treatment of pancreatic cancer, prospectively randomized trials are needed to compare extended surgical procedures with the standard types of resection and the efficiency of various adjuvant therapies.

Adult↗

Carboxy terminal sequence and synthesis of rat kidney laminin gamma 1 chain.

We used antibodies against mouse Englebreth-Holm-Swarm (EHS) tumor laminin to screen a newborn rat kidney lambda gt11 expression library and isolated three overlapping cDNA clones, termed 2b-11 (401 bp), 10-b7 (779 bp), and 2a (2,095 bp). DNA sequence analysis identified these cDNAs as encoding much of the carboxy terminal domain I/II of laminin gamma 1 chain (formerly referred to as B2e), and 1436 bp of the 3' untranslated region. In situ hybridization of fetal (E15) rat sections localized laminin gamma 1 chain mRNA primarily to meninges of the brain, auditory and peripheral nerve fibers, gastrointestinal system, and developing lung airway epithelium. Intense hybridization was also found in early nephric structures and glomeruli of fetal kidneys. In kidneys of three-day-old rats, hybridization persisted over early nephric figures, developing glomeruli, and collecting ducts, but considerably less hybridization was seen over tubules. On Northern blots of neonatal kidney RNA, the three cDNA clones hybridized to two species of 7.5 and 5.5 kb, suggesting that developing rat kidney laminin gamma 1 mRNAs are processed using two different polyadenylation signals.

Amino Acid Sequence↗

Association of DLG5 R30Q variant with inflammatory bowel disease.

Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory diseases of the gastrointestinal system known as the inflammatory bowel diseases (IBD). Recently, Stoll and colleagues reported a novel finding of genetic variation in the DLG5 gene that is associated with IBD (CD and UC combined). We present here a study of the genetic variation described in that report in two well-powered, independent case-control cohorts and one family-based collection, and confirm the proposed association between IBD and the R30Q variant of DLG5 in two of the three studies. We are, however, unable to replicate the other proposed association to the common haplotype described in Stoll et al and suggest that this other finding could conceivably have been partially a statistical fluctuation and partially a result of LD with the replicated R30Q association. This study provides support for the hypothesis that DLG5 constitutes a true IBD risk factor of modest effect.

Case-Control Studies↗

A functional candidate screen for coeliac disease genes.

It is increasingly evident that different inflammatory disorders show some overlap in their pathological features, concurrence in families and individuals, and shared genetic factors. This might also be true for coeliac disease, a chronic inflammatory disorder of the gastrointestinal system, which shares two linkage regions with inflammatory bowel disease: on chromosome 5q31 (CELIAC2 and IBD5) and 19p13 (CELIAC4 and IBD6). We hypothesised that these regions contain genes that contribute to susceptibility to both disorders. The overlapping 5q31 region contains only five positional candidate genes, whereas the overlapping 19p13 region has 141 genes. As the common disease gene probably plays a role in inflammation, we selected five functional candidate genes from the 19p13 region. We studied these 10 positional and functional candidate genes in our Dutch coeliac disease cohort using 44 haplotype tagging single-nucleotide polymorphisms. Two genes from 19p13 showed a small effect on familial clustering: the cytochrome P450 F3 gene CYP4F3 (P(nominal) 0.0375, odds ratio (OR) 1.77) and CYP4F2 (P(nominal) 0.013, OR 1.33). CYP4F3 and CYP4F2 catalyse the inactivation of leukotriene B4 (LTB4), a potent mediator of inflammation responsible for recruitment and activation of neutrophils. The genetic association of LTB4-regulating gene variants connects the innate immune response of neutrophil mobilisation with that of the established Th1 adaptive immunity present in coeliac disease patients. The findings in coeliac disease need to be replicated. Expanding genetic association studies of these cytochrome genes to other inflammatory conditions should reveal whether their causative influence extends beyond coeliac disease.

Case-Control Studies↗

Risk of meconium-stained amniotic fluid in different ethnic groups.

BACKGROUND: Recent studies indicate that the risk of meconium-stained amniotic fluid (MSAF) varies in different ethnic groups. This study prospectively examined the ethnic variation of MSAF and meconium aspiration syndrome, adjusting for gravidity, gestational age (GA), and birth weight. METHOD: The study population consisted of 6901 consecutive live births and included 31 different nationalities, seven main ethnic (race) groups, gravidity between 1 and 19, GA between 22 and 44 weeks, and birth weights between 350 and 6292 gm. RESULTS: The overall incidence of MSAF was 19% (13% thin, 6% thick). The prevalence of meconium aspiration syndrome was 5% in thick MSAF and none in thin MSAF. The incidence of MSAF differs significantly by ethnicity (14% to 30%), gravidity (17% to 23%), GA (6% to 46%), and birth weight (11% to 28%). Multivariate logistic regression analysis using the same variable showed that being black African, post-term, with a gravidity of > or = 7 and a birth weight of > or = 4000 gm significantly increased the chance for MSAF but not meconium aspiration syndrome. After controlling for these clinical variables, the black African infants had a higher percentage of MSAF at all GAs compared with the other ethnic groups. CONCLUSION: This study showed that the risk of MSAF varied by ethnicity and increased with higher gravidity, a GA of > 42 weeks, and a birth weight of > or = 4000 gm The higher incidence of MSAF without an increase in meconium aspiration syndrome in some ethnic groups may indicate advancing maturity of the gastrointestinal system in black ethnic groups compared with others of the same GA.

Amniotic Fluid↗

Decreased mitochondrial tRNALys steady-state levels and aminoacylation are associated with the pathogenic G8313A mitochondrial DNA mutation.

Mutations in human mitochondrial tRNA genes cause a number of multisystemic disorders. A G-to-A transition at position 8313 (G8313A) transition in the mitochondrial tRNALys gene has been associated with a childhood syndrome characterized by gastrointestinal-system involvement and encephaloneuropathy. We have used transmitochondrial cybrid clones harbouring patient-derived mitochondrial DNA with the G8313A mutation for the study of the molecular pathogenesis. Our results showed that mutant mitochondrial cybrids respired poorly, and had severely defective mitochondrial protein synthesis and respiratory-chain-enzyme activity. Mutant cybrids also showed a marked decrease in tRNALys steady-state levels and aminoacylation, suggesting that these molecular abnormalities may underlie the pathogenesis of the mitochondrial G8313A mutation.

Acylation↗

H2-antagonist maintenance therapy versus Helicobacter pylori eradication in patients with chronic duodenal ulcer disease: a prospective study.

BACKGROUND: Few outcome studies directly compare Helicobacter pylori eradication therapy with maintenance H2-antagonist therapy in duodenal ulcer disease. AIM: To examine prospectively the efficacy of H. pylori eradication therapy with ranitidine maintenance therapy over 1 year in patients with confirmed chronic duodenal ulcer. METHODS: One hundred and nineteen patients with active H. pylori infection were randomized to receive ranitidine, 150 mg/day initially (58 patients), or omeprazole, 40 mg/day, amoxycillin 2 g/day and metronidazole 1.2 g/day for 14 days, or omeprazole 40 mg/day and clarithromycin 1.5 g/day, for 14 days (if penicillin-allergic). Symptoms were assessed using the Gastrointestinal System Rating Scale (GSRS) and SF36 quality of life index. RESULTS: 13C urea breath testing confirmed overall treatment success in 100% of patients (58/58) per protocol and 95.1% (58/61) on an intention-to-treat basis. At 4 and 12 months there were no differences in any GSRS symptoms between treatment groups. SF36 analysis showed a perceived health improvement at 4 and 12 months in patients who received H. pylori eradication. However, despite successful H. pylori eradication, one-fifth of patients still required antisecretory therapy. CONCLUSION: Following successful H. pylori eradication, chronic duodenal ulcer patients were at least as well symptomatically as when taking maintenance ranitidine. They perceived that their health had improved, but a subgroup was still acid-suppression dependent.

Adolescent↗

The regulatory effects of whey retentate from bifidobacteria fermented milk on the microbiota of the Simulator of the Human Intestinal Microbial Ecosystem (SHIME).

AIMS: To investigate the effects of whey retentate from Bifidobacteria fermented milk. METHODS AND RESULTS: The simulator of the human intestinal microbial ecosystem (SHIME) was used. The composition of the microbiota and its metabolic activities were analysed. Changes in the microbial composition became apparent within 15 days of the treatment in the vessels representing the ileum and the large intestine. The whey retentate favoured the growth of endogenous bifidobacteria and induced a decrease in Bacteroides fragilis and in sulphite-reducing clostridia, especially Clostridium perfringens. After the administration was stopped, these populations tended to revert to their original levels, except for the streptococci and the staphylococci populations. The treatment also led to an increase in acetic acid, CH4 and CO2 production, suggesting overgrowth of some anaerobic bacteria. Ammonium, generally considered as undesirable, declined. CONCLUSIONS: The whey retentate clearly altered the microbial community in the SHIME. SIGNIFICANCE AND IMPACT OF THE STUDY: Whey retentate appears to exert a beneficial effect on the in vitro gastrointestinal system; these findings warrant confirmation by in vivo studies.

Animals↗

Biphasic responses of equine colonic vessel rings to vasoactive inflammatory mediators.

1. The role of endothelium in modulating equine colonic vessel responses to histamine (HST), 5-hydroxytryptamine (5-HT), bradykinin (BK) and acetylcholine (ACh) was evaluated in vitro. 2. Segments of mesenteric arteries and veins were collected from the left ventral colon of six adult horses destined for euthanasia for reasons unrelated to cardiovascular or gastrointestinal systems. Vessels were gently cleansed and cut into 4 mm wide rings. 3. Three vessel conditions namely endothelium intact, endothelium removed and N omega-nitro-L-arginine methyl ester (L-NAME)-treated were used for both arterial and venous rings. Each ring was placed in an organ bath with oxygenated Tyrode's solution. One side of the ring was fixed to the floor of the bath and the other side to a force-displacement transducer interfaced with a polygraph. 4. An initial tension of 2 g was applied to rings which were allowed to equilibrate for 45 min. The bath solution was gently replaced every 15 min and tension was readjusted to 2 g each time except following the last wash. 5. Rings were precontracted with a single EC25 dose of noradrenaline and after the response plateaued, cumulative concentration (10(-12)-10(-4) M) response curves were determined for each agent on separate rings. The relaxation from the precontracted level to the baseline was considered as 100% relaxation. Maximal relaxation and maximal contractions were statistically analyzed. 6. All agents induced a relaxation response initially, followed by a contractile phase as the concentrations increased in both arteries and veins, thus, making a biphasic concentration-response curve. In arteries, relaxation produced by ACh was significantly greater than 5-HT. Endothelium removal and L-NAME treatment significantly reduced relaxation in arteries. Only endothelium removal produced a significant reduction of relaxation in veins. 7. In both arteries and veins, HST and 5-HT produced significantly greater contraction than ACh or BK. No significant change in contraction was observed in arteries either by endothelium removal or L-NAME treatment, however, contraction was significantly reduced in veins by endothelium removal. 8. These findings suggest that the endothelium plays a major role in modulating equine colonic arterial relaxation via nitric oxide and venous contraction via endothelium-derived contractile mediators, probably endothelin and/or arachidonates.

Acetylcholine↗

Carney complex and the familial lentiginosis syndromes: link to inherited neoplasias and developmental disorders, and genetic loci.

Lentigines, synonymous but not identical to freckles or ephelides, are common skin lesions. In a small number of patients, however, these lesions constitute part of genetic syndromes that are associated with inherited forms of neoplasias or other pathologic processes of the cardiovascular, endocrine, and gastrointestinal systems. The familial lentiginoses, as these syndromes are collectively known, include Carney complex, the LEOPARD and Peutz-Jeghers syndromes, and the newly described 'syndrome of arterial dissections with lentiginosis'; isolated, familial lentiginosis has also been described. In the majority of the reported kindreds with these syndromes, the lesions were inherited in an autosomal dominant manner. The specific genes that are responsible for these disorders have remained elusive, but the genetic loci of Carney complex and Peutz-Jeghers syndromes were recently identified on chromosomes 2p 16 and distal 19p, respectively. Cytogenetic studies of tumours from patients with Carney complex suggest that the gene responsible for most patients with this syndrome may not have a tumour suppression function. We suggest that the genes responsible for the lentiginosis syndromes are important regulators of melanocyte function, they participate in the pleiotropy of human pigmentation, and are involved in the function, growth and proliferation of neural crest and mesenchymal cells.

Diagnosis, Differential↗

Thyroid hormones are important for embryonic to larval transitory phase in zebrafish.

In zebrafish, like many other teleost species, the development and differentiation of many major organs continue unabated into the yolk-sac larval stage before culminating in a free-swimming larva capable of exogenous feeding. We investigated the role of thyroid hormone (TH) in this important embryonic to larval transitory phase. Thyroid hormone receptor (TR) alpha and beta mRNAs are expressed during the early stages of zebrafish embryonic development. Beginning from the midblastula stage, the level of TR beta mRNAs increases dramatically and is maintained until the end of the transitory phase. Excessive exogenous thyroxine (T4; 30 nM) is toxic and causes severe developmental defects. Cotreatment of embryos with amiodarone, an antagonist of TR, and goitrogen methimazole (MMI) lead to severe retardation in the maturation of the gastrointestinal system, swim bladder, and the lower jaw cartilages and the resorption of the yolk sac. The developmental arrest is lethal, and treated larvae do not survive beyond 7 day postfertilization (dpf), but can be completely rescued by the presence of 10 nM T4. We propose that the embryonic to larval transitory phase in many teleost species is characterized by its dependency on the timely synthesis of TH and the concomitant autoinductive increase in TR beta mRNA levels.

Air Sacs↗

Malacoplakia of the ovary, fallopian tube and uterus: a case associated with diabetes mellitus.

Malacoplakia is a chronic xanthogranulomatous inflammation that most commonly affects the urinary tract and the gastrointestinal system of middle-aged women. It is rarely encountered in a female genital tract, and only a handful of cases of malacoplakia of the ovary have been described. We report an unusual case of malacoplakia extensively involving the ovary, fallopian tube and uterus of a 47-year-old woman with poorly controlled diabetes mellitus. Escherichia coli was cultured from the ovarian lesion. To our knowledge, such an extensive female genital malacoplakia associated with diabetes mellitus has not been reported before. Widespread or atypical site malacoplakia occurring in a patient with systemic disease may result from a diminution of macrophagocytic function, either under the influence of the systemic illness or related to corticosteroid excess. We propose that diabetes mellitus without appropriate medical control may have resulted in impaired leukocyte function which, when combined with E. coli infection, led to the development of extensive malacoplakia in the genital tract of this patient.

Diabetes Mellitus, Type 1↗

Sliding hernia simulating esophageal tumor on computed tomography.

Diaphragmatic hernias are the most common abnormalities of gastrointestinal system especially in elderly patients. The radiographic findings of diaphragmatic hernias on esophagram are well known, but when incidentally found in an asymptomatic patient on axial computed tomography (CT) sections, the appearance of diaphragmatic hernia may mimic many other conditions. Our purpose is to present the CT findings of sliding hernia in an incidentally found asymptomatic patient, and to differentiate it from the other abnormalities that can be located in the distal paraesophageal area with the same appearance characteristics.

Diagnosis, Differential↗

MUCLIN expression in the cystic fibrosis transmembrane conductance regulator knockout mouse.

BACKGROUND & AIMS: Cystic fibrosis is characterized by increased secretion of glycoconjugates with altered carbohydrate composition, but no specific gene products that show these changes have been identified. The aim of this study was to use a recently described sulfated mucin-like glycoprotein (MUCLIN: formerly called gp300) as a model glycoconjugate to study such changes in the gastrointestinal system in the cystic fibrosis transmembrane conductance regulator (CFTR) knockout mouse (cftrm1Unc). METHODS: Western and Northern blots were used to determine the tissue levels of MUCLIN and its messenger RNA (mRNA) in normal and CFTR knockout mice. Immunocytochemistry was used to determine the localization of MUCLIN. RESULTS: MUCLIN is expressed in the normal mouse intestinal tract, pancreas, and gallbladder. In CFTR knockout mice, MUCLIN shows increased expression at both mRNA and protein levels in pancreas and duodenum, but not in the gallbladder. In the duodenum, MUCLIN was localized intracellularly in crypt enterocytes and on the luminal surface, and luminal surface labeling was dramatically increased in the CFTR knockout mouse. In the CFTR knockout mouse duodenum and gallbladder, MUCLIN showed retarded electrophoretic migration indicating altered posttranslational processing. CONCLUSIONS: MUCLIN shows increased expression and possibly altered posttranslational processing in the CFTR knockout mouse and will serve as a good model for understanding changes in the composition of mucous secretions in patients with this disease.

Animals↗