Glucagon-like peptide-I and the control of insulin secretion in the normal state and in NIDDM.

Potentiation of glucose-induced insulin secretion by intestinal factors has been described for many years. Today, two major peptides with potent insulinotropic action have been recognized: gastric inhibitory peptide and truncated forms of glucagon-like peptide I, GLP-I(7-37) or the related GLP-I(7-36)amide. These hormones have specific beta-cell receptors that are coupled to production of cAMP and activation of cAMP-dependent protein kinase. Elevation in intracellular cAMP levels is required to mediate the glucoincretin effect of these hormones: the potentiation of insulin secretion in the presence of stimulatory concentrations of glucose. In addition, circulating glucoincretins maintain basal levels of cAMP, which are necessary to keep beta-cells in a glucose-competent state. Interactions between glucoincretin signaling and glucose-induced insulin secretion may result from the phosphorylation of key elements of the glucose signaling pathway by cAMP-dependent protein kinase. These include the ATP-dependent K+ channel, the Ca++ channel, or elements of the secretory machinery itself. In NIDDM, the glucoincretin effect is reduced. However, basal or stimulated gastric inhibitory peptide and glucagon-like peptide I levels are normal or even elevated, suggesting that signals induced by these hormones on the beta-cells are probably altered. At pharmacological doses, infusion of glucagon-like peptide I but not gastric inhibitory peptide, can ameliorate postprandial insulin secretory response in NIDDM patients. Agonists of the glucagon-like peptide I receptor have been proposed as new therapeutic agents in NIDDM.

Immune responses to Helicobacter pylori infection.

Helicobacter pylori (H. pylori) infection is one of the most common infections in human beings worldwide. H. pylori express lipopolysaccharides and flagellin that do not activate efficiently Toll-like receptors and express dedicated effectors, such as γ-glutamyl transpeptidase, vacuolating cytotoxin (vacA), arginase, that actively induce tolerogenic signals. In this perspective, H. pylori can be considered as a commensal bacteria belonging to the stomach microbiota. However, when present in the stomach, H. pylori reduce the overall diversity of the gastric microbiota and promote gastric inflammation by inducing Nod1-dependent pro-inflammatory program and by activating neutrophils through the production of a neutrophil activating protein. The maintenance of a chronic inflammation in the gastric mucosa and the direct action of virulence factors (vacA and cytotoxin-associated gene A) confer pro-carcinogenic activities to H. pylori. Hence, H. pylori cannot be considered as symbiotic bacteria but rather as part of the pathobiont. The development of a H. pylori vaccine will bring health benefits for individuals infected with antibiotic resistant H. pylori strains and population of underdeveloped countries.

Déficits dans les apports nutritionnels chez les candidats a la chirurgie bariatrique [Nutritional deficiencies in candidates for bariatric surgery]

98% of patients who have undergone a gastric bypass for treating severe obesity develop multiple micronutrient deficits. However, prior to surgery, it isn't rare to find nutrient deficiencies. Indeed, the dietary intakes of surgery candidates are often unbalanced, lacking in variety especially in high vitamin and mineral nutrients. We present the preliminary results concerning the qualitative and quantitative analysis in a group of patients waiting for a gastric bypass. The recommended daily amounts in vitamin B9, vitamin D and iron are insufficient in the majority of the patients. The correction of nutritional intakes is advisable, even before the surgery, in order to reduce the risks of developing biological deficiencies.

Advances in the pharmacological treatment of gastro-oesophageal cancer.

Despite a sharp decline in the incidence of gastric cancer during the second half of the 20th century, this malignancy remains the second leading cause of cancer mortality in the world. The incidence and mortality rate of gastric cancer increase with age; at present, the median ages at diagnosis are 67 years for men and 72 years for women in the US. This article reviews and discusses current medical treatment options for both the general population and elderly gastric cancer patients. Management of localized gastric cancer has changed significantly over recent years. Adjuvant chemoradiation is not generally recommended outside the US. After decades of trials of adjuvant chemotherapy with inconclusive results, a significant survival benefit for perioperative combination chemotherapy - as compared with surgery alone - in patients with resectable or locally advanced gastro-oesophageal cancer was recently demonstrated in the UK MAGIC trial. A further large, randomized trial from Japan demonstrated a significant survival benefit for adjuvant chemotherapy with S-1 after D2 resection for gastric cancer. However, both trials are applicable only to the population in which the trials were conducted. Specific data on elderly patients are missing. For patients with metastatic disease, oral fluoropyrimidines, such as capecitabine, have been developed. In Asian patients, treatment with the oral fluoropyrimidine S-1 is safe and effective. Docetaxel, oxaliplatin and irinotecan have demonstrated activity against gastric cancer in appropriately designed, randomized, phase III trials and have increased the available treatment options significantly. In addition, according to preliminary data, trastuzumab in combination with chemotherapy has significantly improved activity when compared to chemotherapy alone in patients with human epidermal receptor (HER)-2-positive gastric and gastro-oesophageal cancers. Thus, therapeutic decisions in patients with advanced gastric cancer may be adapted to the molecular subtype and co-morbidities of the individual patient. Data from retrospective analyses suggest that oxaliplatin seems to be better tolerated than cisplatin in elderly patients.

Neuroendocrine deregulation of food intake, adipose tissue and the gastrointestinal system in obesity and metabolic syndrome.

Obesity is an excess of fat mass. Fat mass is an energy depot but also an endocrine organ. A deregulation of the sympathetic nervous system (SNS) might produce obesity. Stress exaggerates diet-induced obesity. After stress, SNS fibers release neuropeptide Y (NPY) which directly increases visceral fat mass producing a metabolic syndrome (MbS)-like phenotype. Adrenergic receptors are the main regulators of lipolysis. In severe obesity, we demonstrated that the adrenergic receptor subtypes are differentially expressed in different fat depots. Liver and visceral fat share a common sympathetic pathway, which might explain the low-grade inflammation which simultaneously occurs in liver and fat of the obese with MbS. The neuroendocrine melanocortinergic system and gastric ghrelin are also greatly deregulated in obesity. A specific mutation in the type 4 melanocortin receptor induces early obesity onset, hyperphagia and insulin-resistance. Nonetheless, it was recently discovered that a mutation in the prohormone convertase 1/3 simultaneously produces severe gastrointestinal dysfunctions and obesity.

Effects of salbutamol on the contractile properties of human skeletal muscle before and after fatigue.

AIM: The study examined the effects of an oral acute administration of the beta2-agonist salbutamol (Sal) (6 mg) vs. placebo on muscle strength and fatigability in 12 non-asthmatic recreational male athletes in a randomized double-blind protocol. METHODS: Contractile properties of the right quadriceps muscle were measured during electrical stimulations, i.e. twitch, 1-s pulse trains at 20 (P(20) ) and 80 Hz (P(80) ) and during maximal voluntary isometric contraction (MVIC) before (PRE) and after (POST) a fatigue-producing protocol set by an electromyostimulation (30 contractions, frequency: 75 Hz, on-off ratio: 6.25-20s). In addition, the level of muscle voluntary activation was measured. RESULTS: In PRE and POST conditions, the peak torque (PT) of twitch, P(80) and MVIC were not modified by the treatment. The PT in POST P(20) was slightly, although not significantly, less affected by fatigue in Sal compared with placebo condition. Moreover, twitch half-relaxation time at PRE was smaller under Sal than under placebo (P < 0.05). No significant changes in the degree of voluntary activation were observed with Sal treatment in PRE or POST condition. CONCLUSION: Although these findings did not exclude completely an effect of Sal on peripheral factors of human skeletal muscle, oral acute administration of the beta2-agonist Sal seems to be without any relevant ergogenic effect on muscle contractility and fatigability in non-asthmatic recreational male athletes.

Food-dependent Cushing's syndrome: possible involvement of leptin in cortisol hypersecretion.

Stimulation ofcortisol secretion by food intake has been implicated in the pathogenesis of some cases of ACTH-independent Cushing's syndrome, via an aberrant response of the adrenal glands to gastric inhibitory polypeptide (GIP). We report here a novel case of food-dependent Cushing's syndrome in a patient with bilateral macronodular adrenal hyperplasia. In this patient we were able to confirm a paradoxical stimulation of cortisol secretion by GIP in vivo as well as in vitro on dispersed tumor adrenal cells obtained at surgery. In addition to GIP, in vitro stimulation of these cultured tumor adrenal cells with leptin, the secreted product of the adipocyte, induced cortisol secretion. By comparison, no such stimulation was observed in vitro in adrenal cells obtained from another patient with bilateral macronodular adrenal hyperplasia and Cushing's syndrome that did not depend on food intake, in tumor cells obtained from a solitary cortisol-secreting adrenal adenoma, and in normal human adrenocortical cells. These results demonstrate that as in previously described cases of food-dependent Cushing's syndrome, GIP stimulated cortisol secretion from the adrenals of the patient reported here. Therefore, they indicate that such a paradoxical response probably represents the hallmark of this rare condition. In addition, they suggest that leptin, which normally inhibits stimulated cortisol secretion in humans, participated in cortisol hypersecretion in this case. Further studies in other cases of food-dependent Cushing's syndrome, however, will be necessary to better ascertain the pathophysiological significance of this finding.

Transmyocardial laser revascularisation in acutely ischaemic myocardium.

OBJECTIVE: Although recent experience suggests that transmyocardial laser revascularisation (TMLR) relieves angina, its mechanism of action remains undefined. We examined its functional effects and analysed its morphological features in an animal model of acute ischaemia. METHODS: A total of 15 pigs were randomised to ligation of left marginal arteries (infarction group, n = 5), to TMLR of the left lateral wall using a holmium:yttrium-aluminium garnet (Ho:YAG) laser (laser group, n = 5), and to both (laser-infarction group, n = 5). All the animals were sacrificed 1 month after the procedure. Haemodynamics and echocardiography with segmental wall motion score were carried out at both time intervals (scale 0-3: 0, normal; 1, hypokinesia; 2, akinesia; 3, dyskinesia). Histology of the involved area was analysed. RESULTS: Laser group showed no change of the segmental wall motion score of the involved area 30 min after the laser channels were made (score: 0 +/- 0). Infarction and laser infarction groups both showed a persistent and definitive increase of the segmental wall motion score (at 30 min: 1.6 +/- 0.3 and 2 +/- 0, respectively; at 1 month: 1.8 +/- 0.2 and 1.8 +/- 0.4, respectively). These increases were all statistically significant in comparison with baseline values (P < 0.5), however comparison between infarction and laser-infarction groups showed no significant difference. On macroscopic examination of the endocardial surface, no channel was opened. On histology, there were signs of neovascularisation around the channels in the laser group, whereas in the laser-infarction group the channels were embedded in the infarction scar. CONCLUSIONS: In this acute pig model, TMLR did not provide improvement of contractility of the ischaemic myocardium. To the degree that the present study pertains to the clinical setting, the results suggest that mechanisms other than blood flow through the channels should be considered, such as a laser-induced triggering of neovascularisation or neural destruction.

Impact of the phosphatidylinositide 3-kinase signaling pathway on the cardioprotection induced by intermittent hypoxia.

BACKGROUND: Exposure to intermittent hypoxia (IH) may enhance cardiac function and protects heart against ischemia-reperfusion (I/R) injury. To elucidate the underlying mechanisms, we developed a cardioprotective IH model that was characterized at hemodynamic, biochemical and molecular levels. METHODS: Mice were exposed to 4 daily IH cycles (each composed of 2-min at 6-8% O2 followed by 3-min reoxygenation for 5 times) for 14 days, with normoxic mice as controls. Mice were then anesthetized and subdivided in various subgroups for analysis of contractility (pressure-volume loop), morphology, biochemistry or resistance to I/R (30-min occlusion of the left anterior descending coronary artery (LAD) followed by reperfusion and measurement of the area at risk and infarct size). In some mice, the phosphatidylinositide 3-kinase (PI3K) inhibitor wortmannin was administered (24 µg/kg ip) 15 min before LAD. RESULTS: We found that IH did not induce myocardial hypertrophy; rather both contractility and cardiac function improved with greater number of capillaries per unit volume and greater expression of VEGF-R2, but not of VEGF. Besides increasing the phosphorylation of protein kinase B (Akt) and the endothelial isoform of NO synthase with respect to control, IH reduced the infarct size and post-LAD proteins carbonylation, index of oxidative damage. Administration of wortmannin reduced the level of Akt phosphorylation and worsened the infarct size. CONCLUSION: We conclude that the PI3K/Akt pathway is crucial for IH-induced cardioprotection and may represent a viable target to reduce myocardial I/R injury.

Specific inhibition of HCN channels slows rhythm differently in atria, ventricle and outflow tract and stabilizes conduction in the anoxic-reoxygenated embryonic heart model.

The hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are expressed in pacemaker cells very early during cardiogenesis. This work aimed at determining to what extent these channels are implicated in the electromechanical disturbances induced by a transient oxygen lack which may occur in utero. Spontaneously beating hearts or isolated ventricles and outflow tracts dissected from 4-day-old chick embryos were exposed to a selective inhibitor of HCN channels (ivabradine 0.1-10microM) to establish a dose-response relationship. The effects of ivabradine on electrocardiogram, excitation-contraction coupling and contractility of hearts submitted to anoxia (30min) and reoxygenation (60min) were also determined. The distribution of the predominant channel isoform, HCN4, was established in atria, ventricle and outflow tract by immunoblotting. Intrinsic beating rate of atria, ventricle and outflow tract was 164+/-22 (n=10), 78+/-24 (n=8) and 40+/-12bpm (n=23, mean+/-SD), respectively. In the whole heart, ivabradine (0.3microM) slowed the firing rate of atria by 16% and stabilized PR interval. These effects persisted throughout anoxia-reoxygenation, whereas the variations of QT duration, excitation-contraction coupling and contractility, as well as the types and duration of arrhythmias were not altered. Ivabradine (10microM) reduced the intrinsic rate of atria and isolated ventricle by 27% and 52%, respectively, whereas it abolished activity of the isolated outflow tract. Protein expression of HCN4 channels was higher in atria and ventricle than in the outflow tract. Thus, HCN channels are specifically distributed and control finely atrial, ventricular and outflow tract pacemakers as well as conduction in the embryonic heart under normoxia and throughout anoxia-reoxygenation.

Prolonged fluconazole exposure leads to a shift to Candida species with decreased susceptibility in breakthrough candidemia: prospective survey of the Fungal Infection Network of Switzerland

Objectives: To compare the clinical characteristics, species distribution and antifungal susceptibility of Candida bloodstream isolates (BSI) in breakthrough (BTC) vs. non-breakthrough candidemia (NBTC) and to study the effect of prolonged vs. short fluconazole (F) exposure in BTC.Methods: Candida BSI were prospectively collected during 2004- 2006 from 27 hospitals (seven university, 20 affiliated) of the FUNGINOS network. Susceptibility to F, voriconazole (V) and caspofungin (C) was tested in the FUNGINOS mycology reference laboratory by microtitre broth dilution method with the Sensititre YeastOneTM test panel. Clinical data were collected using standardized CRFs. BTC was defined as occurring during antifungal treatment/prophylaxis of at least three days duration prior to the candidemia. Susceptibility of BSI was defined according to 2010/2011 CLSI clinical breakpoints.Results: Out of 567 candidemia episodes, 550 Candida BSI were available. Of these, 43 (7.6%) were from BTC (37/43, 86% were isolated after F exposure). 38 BTC (88.4%) and 315 NBTC (55.6%) occurred in university hospitals (P < 0.001). The majority of patients developing BTC were immunocompromised: higher proportions of haematological malignancies (62.8% in BTC vs. 47.1% in NBTC, P < 0.001), neutropenia (37.2% vs. 11.8%, P < 0.001), acute GvHD (14% vs. 0.2%, P < 0.001), immunosuppressive drugs (74.4% vs. 7.8%, P < 0.001), and mucositis (32.6% vs. 2.3%, P < 0.001) were observed. Other differences between BTC and NBTC were higher proportions of patients with central venous catheters in the 2 weeks preceding candidemia (95.3% vs. 83.4%, P = 0.047) and receiving total parenteral nutrition (62.8% vs. 35.9%, P < 0.001), but a lower proportion of patients treated with gastric proton pump inhibitors (23.3% vs. 72.1%, P < 0.001). Overall mortality of BTC and NBTC was not different (34.9% vs. 31.7%, P = 0.73), while a trend to higher attributable mortality in BTC was found (13.9% vs. 6.9%, P = 0.12). Species identification showed a majority of C. albicans in both groups (51.2% in BTC vs. 62.9% in NBTC, P = 0.26), followed by C. glabrata (18.6% vs. 18.5%), C. tropicalis (2.3% vs. 6.3%) and C. parapsilosis (7.0% vs. 4.7%). Significantly more C. krusei were detected in BTC versus NBTC (11.6% vs. 1.6%, P = 0.002). The geometric mean MIC for F, V and C between BTC and NBTC isolates was not significantly different. However, in BTC there was a significant association between duration of F exposure and the Candida spp.: >10 days of F was associated with a significant shift from susceptible Candida spp. (C. albicans, C. parapsilosis, C. tropicalis, C. famata) to non-susceptible species (C. glabrata, C. krusei, C. norvegensis). Among 21 BTC episodes occurring after £10 days of F, 19% of the isolates were non-susceptible, in contrast to 68.7% in 16 BTC episodes occurring after >10 days of F (P = 0.003).Conclusions: Breakthrough candidemia occurred more often in immunocompromised hosts. Fluconazole administered for >10 days was associated with a shift to non-susceptible Candida spp.. Length of fluconazole exposure should be taken into consideration for the choice of empirical antifungal treatment.

Cancer survival from the incident cases of the Registry of Vaud, Switzerland.

Survival statistics from the incident cases of the Vaud Cancer Registry over the period 1974-1980 were computed on the basis of an active follow-up based on verification of vital status as to December 31, 1984. Product-moment crude and relative 5 to 10 year rates are presented in separate strata of sex, age and area of residence (urban or rural). Most of the rates are comparable with those in other published series from North America or Europe, but survival from gastric cancer (24% 5-year relative rates) tended to be higher, and that from bladder cancer (about 30%) lower than in most other datasets. No significant difference in survival emerged according to residence in urban Lausanne vs surrounding (rural) areas. Interesting indications according to subsite (higher survival for the pyloric region vs the gastric fundus, but absence of substantial differences for various colon subsites), histology (higher rates for squamous carcinomas of the lung, seminomas of the testis or chronic lymphatic leukemias as compared with other histotypes), or site of origin (higher survival for lower limb melanomas), require further quantitative assessment from other population-based series. A Cox proportional hazard model applied to melanomatous skin cancers showed an independent favorable effect on long-term prognosis of female gender and adverse implications for advanced age, stage at diagnosis and tumor site other than lower limb.

Extensive (8 to 12 cm2) noncircumferential endoscopic mucosal resection for early esophageal cancer.

Background: Endoscopic mucosal resection (EMR) is an appealing method for treating intramucosal esophageal cancer but must comply with the following stringent requirements: proper preoperative staging, complete resection of the lesion, obtaining a resected specimen for histologic analysis of safety margins, and squamous reepithelialization without stricture formation. Methods: A rigid esophagoscope was created to resect up to 12 cm(2) of esophageal mucosa in a single specimen and at a constant depth through the submucosa. Under visual control, the esophageal mucosa is sucked into a transparent window and resected with a thin diathermy wire loop in 10 seconds. After extensive preclinical studies in a sheep model, this article reports our early experience in humans. Results: Twenty-one hemi-circumferential EMRs were performed for 11 dysplastic Barrett's esophagi and 10 early squamous cell carcinomas with no perforation, one hemorrhage controlled by embolization of the left gastric artery, and one incomplete resection. Deep safety margins were clear in 19 of 21 resected specimens (2 patients, unfit for operations, had submucosal invasion of squamous cell carcinoma and adenocarcinoma, respectively). Lateral margins were not clear by definition in 7 circumferential Barrett's esophagi, but were clear in 4 incomplete Barrett's esophagi and 10 early squamous cell carcinomas. Conclusions: Large EMRs of 12 cm(2) can safely be performed at the submucosal level in the esophagus. Although feasible in one session, circumferential EMR in humans is not yet advisable because of the risk of stricture formation during the healing phase. The rate of complications of this series of 21 EMRs in humans is acceptable. (Ann Thorac Surg 2010; 89: S2151-5) (C) 2010 by The Society of Thoracic Surgeons

Malignant gastroduodenal obstruction: palliation with self-expanding metallic stents.

PURPOSE: To evaluate the feasibility, efficacy, and tolerance of self-expanding metallic stent insertion under fluoroscopic guidance for palliation of symptoms related to malignant gastroduodenal obstruction. MATERIALS AND METHODS: Seventy-two patients (38 men, 34 women) aged 25-98 years (mean, 62 years) with duodenal (n = 43), antropyloric (n = 13), surgical gastrojejunostomy (n = 10), or pyloroduodenal (n = 6) malignant obstruction were referred for insertion of self-expanding metallic stents over a 6-year period. Stent insertion was performed with use of a peroral or transgastric approach when necessary (n = 11). RESULTS: Stents were successfully inserted in 70 of the 72 patients (97%) and provided symptom relief in 65 patients (90%). Inserted stents were mainly uncovered vascular (n = 55) or enteral (n = 10) Wallstents. One hundred eight stents were initially inserted: one, two, three, or four stents were indicated in 43, 17, nine, and one patient, respectively. Mean follow-up was 119 days (range, 4-513 days). Mean stent patency was 113 days (range, 4-513 days). Mean survival of patients was 120 days. During follow-up, stent obstruction occurred in seven patients as a result of tumoral overgrowth (n = 5) or ingrowth (n = 2). Complications occurred in 12 of the 72 patients (17%), including stent migration (n = 8), stent fracture (n = 1), duodenal perforation (n = 1), and death related to general anesthesia (n = 1). CONCLUSION: Despite a significant complication rate, self-expanding metallic stent insertion under fluoroscopic guidance appears to be a feasible and useful technique in the palliative management of malignant gastroduodenal obstruction.