Small intestinal Na+,K+-adenosine triphosphatase activity and gene expression in experimental diabetes mellitus

The Na+,K+-ATPase plays a key role in the absorption of electrolytes, water, and nutrients from the small intestine. The effect of streptozotocin-induced diabetes mellitus (STZ-DM) on the activity and expression of Na+,K+-ATPase in the rat small intestine was examined in the present study. Diabetes mellitus was induced by a single intraperitoneal injection of STZ (75 mg/kg) and control and STZ-DM rats were killed at day 30 (chronic diabetic state). Levels of Na+,K+-ATPase activity and numbers of sodium pumps were increased two- to threefold in the jejunum and ileum. Sodium pump kinetics were unaltered in STZ-DM. The levels of Na+,K+-ATPase alpha1 and beta1 isoform protein, corresponding mRNAs, and levels of transcription were increased in the jejunal and ileal mucosa of the chronically diabetic rat. The increases in Na+,K+-ATPase functional activity, protein expression, and mRNA were most marked at the level of the ileal mucosa. While a proximal to distal gradient in Na+,K+-ATPase activity and subunit isoform protein levels were observed in both control and diabetic rats, levels of subunit isoform mRNA abundance were similar in both regions of the small intestine in both groups of rats. The alterations in small intestinal Na+,K+-ATPase expression in the chronic diabetic state appear to involve alterations in transcriptional and posttranscriptional events and may likely represent an adaptive response that leads to increased Na+-coupled monosaccharide absorption in the context of a perceived state of nutrient depletion.

Intravenous fish oil emulsion attenuates total parenteral nutrition-induced cholestasis in newborn piglets

Total parenteral nutrition (TPN) causes intrahepatic cholestasis and membrane phospholipid changes. Fatty acid (FA) composition of bile and hepatocyte phospholipid is influenced by dietary FA composition. We hypothesized that altering FA composition of i.v. lipid emulsions modifies 1) severity of TPN-induced cholestasis; 2) hepatocyte membrane composition and function; 3) bile flow and composition. Newborn piglets received either sow's milk, TPN with i.v. soybean oil or TPN with i.v. fish oil (FO). After 3 wk, basal and stimulated bile flow were measured after bolus injections of 20, 50, and 100 micromol/kg of taurocholate (TCA). Bile was analyzed for bile acids, cholesterol, phospholipids, and phospholipid-FA. Sinusoidal and canalicular membrane PL-FA, fluidity, and Na+/K+-ATPase were measured. Although the soybean oil-fed animals developed cholestasis, the FO and milk group had similar liver and serum bilirubin. Basal and stimulated bile flow rates were impaired in the soybean oil but not in the FO group. Hepatocyte membrane FA composition reflected dietary FA. Changes in sinusoidal and canalicular membrane fluidity and sinusoidal Na+/K+-ATPase activity did not explain the effect of FO on TPN-induced cholestasis. Intravenous FO reduces TPN-induced cholestasis by unknown mechanisms.

Small bowel review: Part II

In the past year there have been many advances in the area of small bowel physiology and pathology. In preparation for this review, over 500 papers were assessed; some have been selected and reviewed, with a particular focus on presenting clinically useful information for the practising gastroenterologist.

Review article: olestra and its gastrointestinal safety

Olestra is a fat substitute made from sucrose and vegetable oil. Olestra is neither digested nor absorbed, and therefore adds no calories or fat to the diet. Because the gut is the only organ that is exposed to olestra, the potential for olestra to affect gastrointestinal structure and function, and the absorption of nutrients from the gut, has been investigated. Histological evaluations performed after long-term feeding studies have shown no indications that olestra causes injury to the gastrointestinal mucosa. Olestra is not metabolized by the colonic microflora, and has no meaningful effects on the metabolic function of these organisms. Studies of gastrointestinal transit have shown that the consumption of olestra with food does not affect gastric emptying, or small or large bowel transit times. Olestra does not affect the absorption of macronutrients, water-soluble vitamins or minerals. It causes a dose-responsive decrease in the availability of the fat-soluble vitamins A, D, E and K; however, this potentially adverse effect is offset by the addition of vitamins to olestra-containing foods. Olestra has no consistent effect on the amount of total bile acids excreted in the faeces, and therefore probably has no significant effect on bile acid absorption. The occurrence of gastrointestinal symptoms, including diarrhoea, loose stools, gas and abdominal cramping, after consumption of olestra under ordinary snacking conditions is comparable to that following consumption of triglyceride-containing snacks.

The utility of endoscopy in the management of patients with gastroesophageal reflux symptoms

OBJECTIVE

The utility of endoscopy in the management of patients with symptoms of gastroesophageal reflux disease (GERD) is unclear. The purpose of this prospective study was to assess the impact of endoscopy on the subsequent management of patients with uncomplicated reflux symptoms.

METHODS

A total of 742 patients underwent endoscopy for symptoms of GERD. Endoscopists recorded the therapy before endoscopy, the findings of endoscopy, and the treatment recommendations after endoscopy.

RESULTS

There was no difference in pre-endoscopy therapy or grade of esophagitis in subjects undergoing endoscopy for failed therapy versus GERD symptoms alone. After endoscopy, the most common strategy for patients taking omeprazole was to maintain or increase the dose. For those taking an H2 blocker before endoscopy, the most common outcome was to switch the patient to omeprazole, independent of the grade of esophagitis.

CONCLUSIONS

Most patients undergoing endoscopy for symptoms of GERD were switched to omeprazole regardless of the endoscopic findings. No esophageal cancer was identified and the incidence of Barrett's esophagus was low. It appears that endoscopy itself did not change the management of patients receiving H2-blocker therapy. A trial of a proton pump inhibitor before endoscopy should be considered.

The Second Canadian Gastroesophageal Reflux Disease Consensus: moving forward to new concepts

Gastroesophageal reflux disease (GERD) is a disease with serious consequences that may result in significant impairment in quality of life and disease morbidity. Across all grades of severity of symptoms and severity of underlying esophageal disease, proton pump inhibitors (PPIs) provide therapeutic gains over prokinetics (PKs) or H2 receptor antagonists (H2RAs). The potential cost effectiveness of using medications with higher acquisition costs that may lower health care costs overall is often disregarded when conducting cost comparisons with medications having lower 'up-front' costs. Limiting therapy to less effective agents condemns many patients to protracted suffering, repeated physician visits and needless reinvestigation of symptoms that could have been resolved by appropriate initial therapy. Based on current data, use of any classification of symptom severity as a basis for selecting one class of therapeutic agents over another for first line therapy (i.e. PKs, H2RAs for 'mild' GERD, versus a PPI for 'severe' disease) is unwarranted.

Cholestatic hepatocellular injury with azathioprine: a case report and review of the mechanisms of hepatotoxicity

Azathioprine is a drug commonly used for the treatment of inflammatory bowel disease, organ transplantation and various autoimmune diseases. Hepatotoxicity is a rare, but important complication of this drug. The cases reported to date can be grouped into three syndromes: hypersensitivity; idiosyncratic cholestatic reaction; and presumed endothelial cell injury with resultant raised portal pressures, venoocclusive disease or peliosis hepatis. The components of azathioprine, 6-mercaptopurine and the imidazole group, may play different roles in the pathogenesis of hepatotoxicity. The strong association with male sex, and perhaps with human leukocyte antigen type, suggests a genetic predisposition of unknown type. Many of the symptoms of hepatotoxicity, such as nausea, abdominal pain and diarrhea, can be nonspecific and can be confused with a flare-up of inflammatory bowel disease. As well, the subtype resulting in portal hypertension can occur without biochemical abnormalities. A 63-year-old man with Crohn's disease who is presented developed the rare idiosyncratic form of azathioprine hepatotoxicity, but also had a severe disabling steroid myopathy, peripheral neuropathy, resultant deep venous thrombosis and pulmonary embolism related to immobility, and a nosocomial pneumonia. His jaundice and liver enzyme levels improved markedly on withdrawal of the drug, returning to almost normal in five weeks. Treating inflammatory bowel disease effectively while trying to limit iatrogenic disease is a continuous struggle. Understanding the risks of treatment is the first important step. There must be a low threshold for obtaining liver function tests, especially in men, and alertness to the need to discontinue the drug or perform a liver biopsy should patients on azathioprine develop liver biochemical abnormalities, unexplained hepatomegaly or signs of portal hypertension.

Fermentable dietary fiber increases GLP-1 secretion and improves glucose homeostasis despite increased intestinal glucose transport capacity in healthy dogs

Ileal proglucagon gene expression and postprandial plasma concentrations of proglucagon-derived peptides are reported to change with the type and quantity of dietary fiber ingested by rats. Within the intestine, proglucagon encodes several proglucagon-derived peptides known to modulate intestinal absorption capacity and pancreatic insulin secretion. To determine whether the chronic ingestion of fermentable dietary fiber regulates the expression and synthesis of proglucagon-derived peptides in the distal intestine to modulate glucose homeostasis, the following study was conducted: 16 adult dogs (23 +/- 2 kg) were fed isoenergetic, isonitrogenous diets containing a mixture of high fermentable dietary fibers (HFF) or low fermentable (LFF) wood cellulose for 14 d in a randomized cross-over design. Food was withheld for 16 h before an oral glucose tolerance test was conducted supplying 2 g of glucose/kg body wt, and peripheral blood was collected via a hind-leg catheter at 0, 15, 30, 45, 60, 90 and 120 min for plasma glucose, insulin and glucagon-like peptide-1(7-36)NH2 (GLP-1) analyses. Intestinal samples were collected after the second dietary treatment. Ileal proglucagon mRNA, intestinal (GLP-1) concentrations and the integrated area under the curves (AUC) for plasma GLP-1 and insulin were greater and plasma glucose AUC was reduced when dogs were fed the HFF diet compared to the LFF diet (P < 0.05). Intestinal villi heights, brush border and basolateral glucose transporter protein abundance and jejunal transport capacities were significantly greater when dogs were fed the HFF diet than when fed the LFF diet. In conclusion, improvements in glucose homeostasis are observed in healthy dogs when they ingest fermentable fibers.

Small bowel review: Part I

In the past year there have been many advances in the area of small bowel physiology and pathology. In preparation for this review, over 500 papers were assessed, and some have been selected and reviewed, with a particular focus on presenting clinically useful information for the practising gastroenterologist.

Oral administration of rapamycin and cyclosporine differentially alter intestinal function in rabbits

The immunosuppressive drugs rapamycin (Rap) and cyclosporine A (CsA) are used clinically to modify or abolish immune-mediated functions. This study examined the effect of orally administered regimens of Rap, CsA, and a combination of Rap/CsA on intestinal function in male New Zealand white rabbits. Animals received oral doses of CsA (15 mg/kg/body weight/day), low-dose (LD) and high-dose (HD) Rap (0.25 or 1 mg/kg/body wt/day, respectively), or Rap/CsA (0.25 and 5 mg/kg/body wt/day, or 0.5 and 5 mg/kg/body wt/day, respectively) for 20 days. We measured in vitro uptake of nutrients and permeability, and morphometric measurements in the jejunum and ileum were made. Animals receiving HD-Rap or HD-Rap/CsA had decreased food intake, body weight, and intestinal weight, when compared with LD-Rap, LD-Rap/CsA, CsA, or controls. The maximal transport rate (Vmax) for the active jejunal uptake of D-glucose was increased in HD-Rap and CsA, but not in the HD-Rap/CsA-treated animals. The jejunal Vmax of D-glucose in the LD-Rap- or -Rap/CsA-treated animals was no different from controls. In the HD-Rap- and HD-Rap/ CsA-treated animals, jejunal rates of uptake of stearic, linoleic, and linolenic acids were reduced when compared with controls. Jejunal and ileal permeability (as assessed by the passive uptake of L-glucose, tissue conductance, and mucosal-to-serosal flux of [3H]inulin) was increased in animals treated with HD-Rap or HD-Rap/CsA, when compared with CsA or controls. These parameters of permeability were no different at lower doses of Rap or Rap/CsA. The jejunal and ileal villous surface area was increased in CsA, but decreased in HD-Rap or HD-Rap/CsA animals. Thus, HD-Rap given alone or in combination with CsA reduced body weight gain, in part due to reduced food intake and malabsorption of lipids, which was due at least in part to reduced intestinal surface area. The relevance of these findings to patients undergoing chronic immunosuppressive drug therapy needs to be established.

From bench to bedside and back--report on the European Helicobacter pylori Study Group Xth International Workshop on Gastroduodenal Pathology and Helicobacter pylori

The Xth International Workshop on Gastroduodenal Pathology and Helicobacter pylori was held in Lisbon, Portugal, from September 12 to 14, 1997. State-of-the-art reviews and research findings were presented to over 2000 participants. This review focuses on important new developments and serves as a rapid communication of clinically relevant material.

Early dietary experience influences ontogeny of intestine in response to dietary lipid changes in later life

This study was undertaken to test the hypothesis that a change in the mother's diet at the time of birth and continued during suckling modifies the intestinal transport of nutrients in the suckling offspring. Pregnant rat dams were fed one of four semisynthetic diets during pregnancy [high or low n-6/n-3 diet or a diet enriched with arachidonic acid (AA) or docosahexaenoic acid (DHA)] and were fed the same diet at the time of birth or switched to another diet. The greatest body weight gain was in the suckling rats (15-16 days of age) fed a low n-6/n-3 diet. Switching from this diet caused weight loss, and the observed weight gain with the low n-6/n-3 diet was prevented by previous exposure of the mother to the high n-6/n-3 diet or the AA- or DHA-containing diet. Although continuous feeding of a high n-6/n-3 diet to the mother during pregnancy and lactation was associated with the lowest in vitro rates of fructose uptake, switching the mother to another diet during lactation did not necessarily correct the low absorption. In contrast, continuous feeding of a high n-6/n-3 diet to the mother during pregnancy and lactation is associated with the highest maximal transport rate of glucose uptake into the jejunum and ileum. Jejunal uptake of fatty acids 12:0, 18:0, 18:3(n-3), and cholesterol was less with the low n-6/n-3 diet compared with the high n-6/n-3 diet, whereas the ileal uptake of 18:0 and 18:3(n-3) was higher with the low n-6/n-3 diet. Thus the ontogeny of the intestine is critically influenced by the mother's diet during gestation as well as during the nursing period. Some of the diet-associated changes in nutrient uptake resulting from the mother's diet during pregnancy could be corrected by dietary interventions introduced after birth.

Ontogeny of the small intestine

During development the gastrointestinal tract undergoes marked changes in many physiological and anatomic properties. The remarkable degree of coordination between the development of the gastrointestinal function suggests that the processes may be signalled by some factors, such as weaning, nutrient intake, growth and hormones. The interactions between nutrition and intestinal development begin when fetuses start swallowing amniotic fluid and extend past weaning. Hormonal control plays a major role in the ontogeny of the small intestine. There are late effects of early nutrition, and the normal progress of ontogeny may be important to ensure that the intestine is capable of adaptation in later life.

Short-chain fatty acid-supplemented total parenteral nutrition alters intestinal structure, glucose transporter 2 (GLUT2) mRNA and protein, and proglucagon mRNA abundance in normal rats

Intestinal adaptation is a complex physiologic process that is not completely understood. Intravenous short-chain fatty acids (SCFAs) enhance intestinal adaptation after 80% enterectomy in rats. The purpose of this study was to examine rapid responses to SCFA-supplemented total parenteral nutrition (TPN) in the normal small intestine. After jugular catheterization, 31 Sprague-Dawley rats (weighing 258 +/- 3 g) were randomly assigned to receive standard TPN or an isoenergetic, isonitrogenous TPN solution supplemented with SCFAs (TPN+SCFA). Intestinal samples were obtained after 24 or 72 h of nutrient infusion. TPN+SCFA for 24 h increased (P < 0.05) the ileal RNA concentration (microg RNA/mg ileum) whereas TPN+SCFA for 72 h increased (P < 0.05) the ileal DNA concentration (microg DNA/mg ileum) and decreased (P < 0.05) the ileal protein concentration (microg protein/mg ileum). Ileal proglucagon mRNA abundance was elevated (P < 0.05) after 24 h of TPN+SCFA infusion and returned to levels seen with control TPN by 72 h. Glucose transporter 2 (GLUT2) mRNA was significantly higher (P < 0.05) in the TPN+SCFA groups at both time points when compared with control TPN groups. Ileal GLUT2 protein abundance in the 72-h TPN+SCFA group was significantly higher (P < 0.05) than that of all other groups. Sodium-glucose cotransporter (SGLT-1) mRNA and protein abundance and uptake of D-fructose and D-glucose did not differ between groups. Jejunal uptake of L-glucose and lauric acid was significantly higher (P < 0.05) after 72 h of TPN+SCFA than after 24 h, whereas the 24- and 72-h TPN groups did not differ. In summary, SCFAs led to rapid changes in ileal proglucagon and glucose transporter expression in rats receiving TPN and provide insights into therapeutic management of individuals with short bowel syndrome or intestinal malabsorption syndromes.

Characterization of a cDNA encoding a novel plant poly(A) polymerase

We have isolated cDNA clones encoding a novel factor (PAP-I) that is a component of a multi-subunit poly(A) polymerase from pea seedlings. The encoded protein, when isolated from appropriately engineered Escherichia coli, was active as a poly(A) polymerase, either with an associated RNA binding cofactor (PAP-III) or with free poly(A) as an RNA substrate. The latter observation indicates that PAP-I is in fact a poly(A) polymerase. PAP-I bore a striking resemblance to an as yet uncharacterized cyanobacterial protein. This observation suggested a possible chloroplast localization for PAP-I. This hypothesis was tested and found to be substantiated; immunoblot analysis identified PAP-I in chloroplast but not nuclear extracts. Our results suggest that PAP-I is a component of the machinery that adds poly(A) to chloroplast RNAs.

Optimization of acid suppression for patients with peptic ulcer bleeding: an intragastric pH-metry study with omeprazole

OBJECTIVE

To study whether an intravenous infusion dose of omeprazole (80 mg + 8 mg/h) during 24 h can be subsequently reduced with maintained effect. Second, to study the effect of oral omeprazole 20 mg given once or twice daily up to day 10, after cessation of a 3-day intravenous infusion (80 mg + 8 mg/h).

DESIGN

Prospective, randomized, partly blinded study.

METHODS

Twelve Helicobacter pylori(+) patients and 12 H. pylori(-) subjects were included. In part I the patients received omeprazole, 80 mg + 8 mg/h, during 24 h followed by 8, 4 or 2 mg/h. In part II the subjects received 80 mg + 8 mg/h during 3 days followed by 20 mg omeprazole orally, once or twice daily until day 10. Intragastric pH was measured.

RESULTS

All H. pylori(+) patients showed a rapid increase of intragastric pH with a mean intragastric pH of 6.7 during the second half of the first day. After the subsequent dose reduction, the mean pH decreased to 6.1-6.2. Patients continuing on 8 mg/h showed the best results. Likewise, all H. pylori(-) subjects showed a rapid and sustained reduction of intragastric acidity during the infusion. Subsequent dose reduction to 20 mg once daily led to a stable fraction of time with pH > 3 of 72%.

CONCLUSIONS

Omeprazole given as a continuous infusion of 80 mg + 8 mg/h for 72 h followed by omeprazole 20 mg once daily raised the intragastric pH to and above levels alleged to allow haemostasis in patients with peptic ulcer bleeding and subsequent healing of the ulcer.

Overview of olestra: a new fat substitute

Olestra is a mixture of hexa-, hepta- and octa-esters formed from the reaction of sucrase and long chain fatty acids isolated from edible oils. Olestra has properties similar to those of traditional triglycerides but is not hydrolyzed by pancreatic lipases and, therefore, serves as a noncaloric replacement for fats in the diet. The safety of olestra has been established in over 100 studies in seven different species of animals, with confirmatory safety data coming from approximately 75 human studies; consumption of olestra at levels typical for savoury snacks does not result in reports of gastrointestinal problems in humans. This is consistent with the results of studies of the physiological and morphological effects of olestra in animals and in humans. It is anticipated that olestra will be available in Canada in the near future. Patients will soon be asking their physicians about its use. This article provides an overview of olestra.

Canadian Helicobacter pylori consensus conference. Canadian Association of Gastroenterology

These guidelines were created to dispel confusion and provide guidance about how the isolation of Helicobacter pylori infection has led to new opportunities and initiatives to improve patient care. The guidelines are designed for practical application in management decisions, but must remain flexible and amenable to change with new information. Updated versions of the recommendations are anticipated. Although it is now clear that H pylori is a major gastrointestinal pathogen, the extent of the clinical consequences posed by this microorganism has yet to be fully defined.

Stanniocalcin: a novel protein regulating calcium and phosphate transport across mammalian intestine

Stanniocalcin (STC) is an anti-hypercalcemic glycoprotein hormone previously identified in the corpuscles of Stannius in bony fish and recently in the human genome. This study undertook to express human STC in Chinese hamster ovary (CHO) cells and to determine its effects on calcium and phosphate absorption in swine and rat intestine. Unidirectional mucosal-to-serosal (Jm-->s) and serosal-to-mucosal (Js-->m) 45Ca and 32P fluxes were measured in vitro in duodenal tissue in voltage-clamped Ussing chambers. Addition of STC (10-100 ng/ml) to the serosal surface of the duodenum resulted in a simultaneous increase in calcium Jm-->s and Js-->m fluxes, with a subsequent reduction in net calcium absorption. This was coupled with an STC-stimulated increase in phosphate absorption. Intestinal conductance was increased at the highest dose of STC (100 ng/ml) in swine tissue. The addition of STC to the mucosal surface had no effect on calcium and phosphate fluxes. STC at doses of 10-1,000 ng/ml had no effect on short-circuit current in any region of the rat intestine. In conclusion, human recombinant STC decreases the absorption of calcium and stimulates the absorption of phosphate in both swine and rat duodenum. STC is a novel regulatory protein that regulates mammalian intestinal calcium and phosphate transport.

Hemorrhagic intestinal Henoch-Schonlein purpura complicated by cytomegalovirus infection

A 54-year-old man on hemodialysis for acute chronic renal failure and on corticosteroids for Henoch-Schonlein purpura developed massive hematochezia. After extensive clinical investigation, an ileal bleeding site was identified and surgically removed. Pathological examination of the diseased bowel segment revealed an extensive vasculitis with mucosal ulceration attributable to Henoch-Schonlein purpura as well as florid cytomegalovirus infection.

Pharmacokinetics and pharmacodynamics during treatment with the omeprazole 20 mg enteric-coated tablet and 20 mg capsule in asymptomatic duodenal ulcer patients

This study compared the 24 h intragastric pH profile and bioavailability at repeated dosing conditions of the omeprazole 20 mg enteric-coated tablet versus the 20 mg capsule. Forty duodenal ulcer patients in asymptomatic remission completed this randomized open two-way crossover study. Omeprazole 20 mg tablets or capsules were administered for seven days in each period. A 24 h pH recording was performed before the start of treatment and on day 7 of each treatment period. Plasma concentrations of omeprazole were determined 24 h after the dose. The treatment periods were separated by two to four weeks. The difference in percentage of time with pH of at least 3 was less than 16% in favour of the tablet (not significant). The estimated mean area under the plasma concentration-time curve as well as the maximum plasma concentration (Cmax) for omeprazole were 18% and 41% higher, respectively, for the tablet versus the capsule, with the latter percentage being statistically significant. The time to reach Cmax (tmax) with the tablet was, on average, about 0.5 h longer than to reach the tmax of the capsule. This study indicates that the enteric-coated tablet formulation of omeprazole is biodynamically equivalent to the capsule regarding their effects on intragastric pH during repeated dosing.

Influence of food on the bioavailability of an enteric-coated tablet formulation of omeprazole 20 mg under repeated dose conditions

The objective of this study was to investigate the influence of food on the bioavailability of omeprazole (20 mg) given as an enteric-coated tablet under repeated dose conditions. This open randomized crossover study consisted of three seven-day treatment periods, each separated by a drug-free period. During each treatment period an enteric-coated tablet of omeprazole was taken once daily either under fasting conditions, or immediately before or after a standardized breakfast. On the last day of each treatment period, blood samples for the determination of plasma omeprazole concentrations were collected at baseline and at predetermined intervals over the 24 h period following drug administration. Fifty-seven male and female subjects, aged 18 to 52 years, completed the study according to the protocol. No statistically significant differences were found when comparing either the before breakfast or after breakfast treatment regimens with the fasting regimen for the estimated mean area under the plasma concentration-time curve (AUC). The maximum plasma concentration was not found to differ significantly among any of the treatment regimens. However, the lower limit of the CI for the comparison of fasting/before breakfast was not contained within the limits of bioequivalence. The time to reach maximum plasma concentration was significantly different when fasting and after breakfast regimens were compared. Thus, under repeated dose conditions, food has no influence on the bioavailability (expressed as AUC) of omeprazole given as the enteric-coated tablet formulation.

Inhibition of lipid absorption as an approach to the treatment of obesity

A reduction in fat intake may be achieved by making educated choices to reduce total calorie intake, to consume a lower quantity of total fats, or to modify the ratio of saturated-to-polyunsaturated lipids. Leptin agonists or NPY or CCK antagonists may prove to be useful to diminish appetite and thereby reduce the total intake of food. But eating has such cultural, social, and hedonistic attributes that such a single-pronged approach is unlikely to be successful. The use of fat substitutes may prove to be popular to provide a wide range of snack food options, but these are likely to be of minimal use in weight reduction programs because of their distribution of additives in only a limited number of foods. The inhibitors of lipid digestion will be modestly successful in the short term; their long-term success will be influenced by gastrointestinal adverse effects and the need to consume fat-soluble vitamin supplements to prevent the development of fat-soluble vitamin deficiencies. The inhibition of lipid absorption is an attractive targeted approach for the treatment of obesity, since this would reduce the uptake of visible as well as invisible fats, which would potentially offer convenient dosing, and could also be a means to inhibit secondarily the uptake of carbohydrate calories.

Helicobacter pylori: from bench to bedside

With the exponential increase in research in the field of Helicobacter pylori a paradigm shift has occurred. It is now recognized that H pylori is a chronic infection of the stomach causing inflammation. Some patients remain asymptomatic, while others may develop dyspepsia, duodenal or gastric ulcer, gastric cancer or a mucosa-associated lymphoid tissue lymphoma. However, the role of H pylori in contributing to nonulcer dyspepsia or nonsteroidal anti-inflammatory drug gastropathy remains controversial. An effective vaccine against H pylori is years away. Major interest has focused on the questions "who should be investigated and therefore treated" and "what is the latest gold standard for eradication of H pylori"? In Europe, guidelines have been developed to help the practitioner answer these important questions. Canadian guidelines will soon be available. For persons with known peptic ulcer disease there should be unequivocal acceptance that the good clinical practice of eradicating H pylori will result in substantial savings in health care expenses. The original 'classical triple therapy' (bismuth, metronidazole and tetracycline [BMT]) has now been surpassed by the combination of a proton pump inhibitor (PPI) plus two antibiotics (metronidazole plus clarithromycin; amoxicillin plus clarithromycin; or amoxicillin plus metronidazole), each given twice a day for one week. In Canada, the regimen of omeprazole plus one antibiotic (amoxicillin or clarithromycin) was approved recently but gives an eradication rate that is lower than the current target of 90%. According to the European (Mäastricht) recommendations, if a single treatment attempt with PPI plus two antibiotics fails, PPI plus BMT is recommended.