Formulation and Performance of NBR/CR-Based High-Damping Rubber Composites for Soundproof Using Orthogonal Test

Multiple functional-material-filled nitrile butadiene rubber/chloroprene rubber (NBR/CR) acoustic composites were extensively studied and prepared. According to the orthogonal test table L25 (5⁶), 25 groups of samples were prepared by using a low-temperature one-time rubber mixing process. With tensile strength, average transmission loss, and damping peak as indexes, the influence degree of different factors and levels on the properties of acoustic composites was quantitatively discussed and analyzed. The matrix weight analysis was employed to optimize the material formula of rubber composites, and the corresponding influence weight was given. Results showed that the acoustic composite with blending ratio of 70/30 for NBR/CR matrix had preferable mechanical and acoustic properties; adding mica powder (MP) and montmorillonite (MMT) in matrix contributed to improve all above three indexes owing to their specific lamellar structures; hollow glass beads (HGB) had a positive influence on improving acoustic property due to its hollow microcavities, however, it had a negative impact on damping property because of the smooth spherical surfaces. Accordingly, the optimal formulation was found to be NBR/CR blending ratio of 70/30, MP of 10 phr (per hundred rubber), HGB of 4 phr, and MMT of 10 phr.

Design and Ductile Behavior of Torsion Configurations in Material Extrusion to Enhance Plasticizing and Melting

In the present work, the ductile formation mechanism of a newly proposed torsion configuration has been investigated. One of the unique attributes of this paper is the first-time disclosure of the design and fabrication of a novel prototype screw with torsional flow character validating the orthogonal test model experimentally. The torsional spiral flow patterns that occurred in the torsion channel cause a ductile deformation of polymer in the form of a spiral, which in turn enhances the radial convection, achieving an effective mass transfer of material from the top region to the bottom region and vice versa. Furthermore, the characteristic parameters of torsion configuration have a significant influence on the plasticizing and melting capability of polymer. By range analysis and weight matrix analysis, the best factor and level combination was obtained. Results indicated that the aspect ratio of the torsion channel is almost equal to 1, and the plasticizing and melting capability of polymer is optimal. This novel design innovation offers a paradigm shift in the energy-efficient plasticization of polymer compounds.

Application of Biodegradable and Biocompatible Nanocomposites in Electronics: Current Status and Future Directions

With the continuous increase in the production of electronic devices, large amounts of electronic waste (E-waste) are routinely being discarded into the environment. This causes serious environmental and ecological problems because of the non-degradable polymers, released hazardous chemicals, and toxic heavy metals. The appearance of biodegradable polymers, which can be degraded or dissolved into the surrounding environment with no pollution, is promising for effectively relieving the environmental burden. Additionally, biodegradable polymers are usually biocompatible, which enables electronics to be used in implantable biomedical applications. However, for some specific application requirements, such as flexibility, electric conductivity, dielectric property, gas and water vapor barrier, most biodegradable polymers are inadequate. Recent research has focused on the preparation of nanocomposites by incorporating nanofillers into biopolymers, so as to endow them with functional characteristics, while simultaneously maintaining effective biodegradability and biocompatibility. As such, bionanocomposites have broad application prospects in electronic devices. In this paper, emergent biodegradable and biocompatible polymers used as insulators or (semi)conductors are first reviewed, followed by biodegradable and biocompatible nanocomposites applied in electronics as substrates, (semi)conductors and dielectrics, as well as electronic packaging, which is highlighted with specific examples. To finish, future directions of the biodegradable and biocompatible nanocomposites, as well as the challenges, that must be overcome are discussed.

Relationship between abnormal TOX3 gene methylation and polycystic ovarian syndrome

OBJECTIVE

The purpose of this work was to examine the relationship between abnormal TOX3 gene methylation and the occurrence of polycystic ovarian syndrome (PCOS).

PATIENTS AND METHODS

We selected 30 patients with PCOS and 30 control volunteers. Serum luteinizing hormone, estradiol, testosterone, and thyroid stimulating hormone were detected, methylation, mRNA and protein level of TOX3 were measured.

RESULTS

Serum luteinizing hormone, estradiol, testosterone, and thyroid stimulating hormone were significantly higher and follicle stimulating hormone and prolactin were significantly lower in PCOS patients than in the control group. Methylation of the promoter of TOX3 in serum and granular cells was significantly lower in PCOS than in the control group. The mRNA levels of TOX3 in serum were lower in the PCOS group. The levels of TOX3 protein in serum and granular cells was significantly lower in PCOS group than in the control group.

CONCLUSIONS

Overall, abnormal TOX3 methylation possibly resulting in changes in TOX3 protein expression is closely related to the occurrence of PCOS and may play a role the development of the pathology.

Reduction of angiocidin contributes to decreased HepG2 cell proliferation

BACKGROUND

Angiocidin plays a key role in angiogenesis and tumor progression. High angiocidin expression is detected in some kind of solid tumors and tumor vascular endothelial cells. Several reports have shown the inhibition of angiogenesis and tumor growth caused by angiocidin. However, the role of angiocidin in liver cancers growth is still unclear.

OBJECTIVES

To examine angiocidin expression in SMMC-7221 and HepG2 cells and the role of angiocidin in liver cancer cell growth.

METHODS

RT-PCR and western blot are used in this study to detect angiocidin expression. SiRNA and MTT experiments are used in exploring the role of angiocidin in tumor cell growth.

RESULTS

Our study showed high angiocidin expression in two kinds of liver cancer cells. Angiocidin protein production in HepG2 cells were reduced significantly by siRNA. When HepG2 cells were transfected with siRNA-angiocidin, these cells showed very low proliferation activity compared with control cells. Our study suggests that reduction of angiocidin may contribute to decreased proliferation activity in liver cancer cells.

CONCLUSION

Angiocidin is highly expressed in liver cancer cells, and it may play a key role in tumor growth of liver cancers.

Low prevalence of colonoscopic surveillance of inflammatory bowel disease patients with longstanding extensive colitis: a clinical practice survey nested in the CESAME cohort

BACKGROUND

Surveillance colonoscopy is recommended for inflammatory bowel disease (IBD) patients with longstanding extensive colitis (LEC).

AIMS

To assess modalities and results of colonoscopic surveillance in a subset of CESAME cohort patients at high risk of colorectal cancer (CRC) and followed in university French hospitals.

METHODS

Among 910 eligible patients with more than a 7-year history of extensive colitis at CESAME enrolment, 685 patients completed a questionnaire on surveillance colonoscopy and 102 were excluded because of prior proctocolectomy. Finally, 583 patients provided information spanning a median period of 41months (IQR 38-43) between cohort enrolment and the end of follow-up. Details of the colonoscopic procedures and histological findings were obtained for 440 colonoscopies in 270 patients.

RESULTS

Only 54% (n=312) of the patients with LEC had at least one surveillance colonoscopy during the study period, with marked variations across the nine participating centres (27% to 70%, P≤0.0001). Surveillance rate was significantly lower in Crohn's colitis than in ulcerative colitis (UC) (48% vs. 69%, P≤0.0001). Independent predictors of colonoscopic surveillance were male gender, UC IBD subtype, longer disease duration, previous history of CRC and disease management in a centre with large IBD population. Random biopsies, targeted biopsies and chromoendoscopy were performed during respectively 71%, 27 and 30% of surveillance colonoscopies. Two cases of high-grade dysplasia were detected in patients undergoing colonoscopic surveillance. Two advanced-stage CRC were diagnosed in patients who did not have colonosocopic surveillance.

CONCLUSIONS

Colonoscopic surveillance rate is low in IBD patients with longstanding extensive colitis.

Fermentation of starch stimulates propagated contractions in the human colon

BACKGROUND

In healthy humans, up to 30 g of daily ingested starch escape small intestinal digestion, and are fermented in the colon. This physiological starch malabsorption could modify colonic motility through metabolites such as short-chain fatty acids produced by fermentation.

METHODS

Ten healthy volunteers swallowed a probe, consisting of an infusion catheter, six perfused catheters and a balloon connected to a barostat. On two consecutive days colonic motility was recorded in fasting subjects in the basal state (1 h), and then during (3 h), and after (2 h) the intracolonic infusion of 750 mL of isoosmotic and isovolumetric solutions containing sodium chloride with or without 15 g wheat starch. We determined (i) the volume of hydrogen and methane exhaled in breath, (ii) a global motility index and the number of high amplitude propagated contractions (HAPCs), and (iii) the mean balloon volume, reflecting the tonic motor activity.

KEY RESULTS

[median (IQR)] Compared to the basal period, colonic infusion of starch or saline did not modify the colonic motility index and tone. However, the number of HAPCs was significantly higher during and after infusion of starch than of saline [4.5 (2.75-6.5) vs 0.96 (0-2.66)/5 h, starch vs saline respectively; P = 0.011].

CONCLUSIONS & INFERENCES

In healthy humans, colonic fermentation of a physiological malabsorbed amount of starch has no effect on the tonic and phasic colonic motor activities, but produces a significant increase in the number of HAPCs. This may participate in the physiological propulsion of colonic contents.

[Gastro-esophageal reflux through gastric antisecretory drugs]

During the 20th century, gastro-esophageal reflux moved from the status of a rare and severe disease to that of a frequent disease occurring mostly, in the absence of any significant lesions. Proton pump inhibitors (PPIs) are the mainstay of its therapy and are prescribed mainly in an empirical way. Extradigestive manifestations require more accurate diagnostic tests and therapeutic management. The modalities of prescription of the PPIs quickly progressed toward the on-demand therapy and over-the-counter PPIs should become widespread. The relative failures of PPIs led to a profusion of new antisecretory agents but clinical improvements are presently disappointing and the rationale of this escalation is questionable. The concept of non acid gastro-esophageal reflux opens more innovative diagnostic and therapeutic perspectives which, however, must be validated. In this respect, endoscopic treatment needs more reliable techniques and more rigorous trials. Gastro-esophageal reflux refractory to PPIs corresponds mainly to functional esophageal disorders that need diagnostic and therapeutic improvements. Barrett's esophagus constitutes a major challenge for the next few years. Its screening and its prevention seem, for the moment, inaccessible. Its survey and the prevention of its complications should benefit from progress of diagnostic and interventional endoscopy.

[Psychosocial distress and communication about cancer in ill partners and their spouses]

INTRODUCTION

Each cancer can have a psychological impact not only on the patient himself/herself, but also on his/her spouse.

OBJECTIVE

Our study concerned 30 couples encompassing a member treated for a cancer, non related to gender. It was aimed at determining the links between the levels of psychosocial distress measured in both members of each couple, patients' sociodemographic and clinical characteristics, as well as communication skills about cancer in both members of the couples.

METHODS

Psychosocial distress and communication about cancer were measured by the general health questionnaire (GHQ-28) and the openness to discuss cancer in the nuclear family (ODCF), with an additional version adapted for the spouse on the occasion of this study.

RESULTS

A positive correlation was found between the respective scores of the two members of the couples, for the GHQ-28 (r=0.53; p=0.005) as well as for the ODCF (r=0.44; p=0.024). GHQ-28 scores were not associated with the sociodemographic characteristics of the patients, nor with the stage of cancer, the number of months elapsed since the diagnosis of cancer, or the ODCF personal or spouse's score. On the other hand, when the communication within each couple was classified into concordant (insufficient or, on the contrary, open for both members) or discordant (insufficient for one of the two members and open for the other), and after controlling for gender, higher levels of psychosocial distress were found in patients (p=0.038) as well in spouses (p=0.052) belonging to discordant compared with concordant couples.

CONCLUSION

These results suggest an effect of contamination or a mutual reinforcement of the distress of each member of such couples, as well as the presence of relatively similar styles of communication in the two partners of each couple. They also underline the possible adaptive function of a restricted style of communication about cancer, if such a restriction is shared by both the members of the couple, and incites particular attention to be paid to couples where one of the partners, but not the other, adopt an open style of communication about cancer.

Effects of therapeutic doses of lactulose vs. polyethylene glycol on isotopic colonic transit

BACKGROUND

Lactulose and polyethylene glycol are osmotic agents used to treat idiopathic chronic constipation.

AIM

To compare the effects of low doses of lactulose and PEG 4000 on transit time measured by scintigraphy in normal subjects.

METHODS

For 5 days, 10 healthy subjects received either 10 g b.d. of lactulose or PEG 4000 in a randomized, double-blind, crossover study. On the evening of day 4, they took a capsule containing Amberlite resin pellets labelled with (111)In. On day 5, after a 1000 kcal test meal labelled with 99 Tcm, gastric, small bowel and colonic transits were measured.

RESULTS

Gastric emptying and small bowel transit time were not different. Ascending colon emptying curve was significantly accelerated with lactulose in comparison with polyethylene glycol (P = 0.001) and, respectively, 50 +/- 18% vs. 35 +/- 18% of the radioactivity had left the ascending colon at the end of the study (P < 0.05). The descending colon filling curves, variations in the geometric centre and numbers of scintigraphic movements were not different.

CONCLUSIONS

In healthy subjects, in comparison to PEG 4000, usual therapeutic doses of lactulose significantly accelerate ascending colon emptying. This result supports a stimulating motor effect of colonic fermentation of lactulose.

Adult celiac disease with severe or partial villous atrophy: a comparative study

BACKGROUND AND AIMS

While severe villous atrophy (SVA) is the most typical histological feature in adult celiac disease (ACD), partial villous atrophy (PVA) is now also frequently found. So far, the impact of the severity of villous atrophy on the clinical presentation of ACD has been scarcely investigated. We aimed to compare the clinical, biological and immune features and outcomes in ACD patients presenting with PVA at diagnosis versus patients with SVA.

PATIENTS AND METHODS

Medical files of 48 patients with ACD diagnosed between 1992 and 2003 were retrospectively studied. The diagnosis was based on the presence of intestinal villous atrophy, with increases in intraepithelial lymphocytes and circulating celiac specific antibodies. Villous atrophy was classified as severe (subtotal and total) or partial. Symptoms, biological signs of malabsorption, immune markers, bone mineral density at diagnosis and response to gluten-free diet were recorded.

RESULTS

At diagnosis, ten patients (four M/six F) had PVA and 38 patients (five M/33 F) had SVA, with a median age of 54 and 33 years, respectively (p<0.05). Positivity for specific antibodies, HLA typing and frequency of autoimmune disease at diagnosis were similar in both PVA and SVA patients, as was their response to gluten-free diet. Diarrhea, malabsorption syndrome and osteopenia were independent of the degree of villous atrophy.

CONCLUSION

PVA was observed in 21% of patients with ACD. Except for their older age at diagnosis, patients with PVA presented with similar clinical, biological and immune characteristics and outcomes as did patients with SVA.

Co-transfection of GK and mhPINS genes into HepG2 cells confers glucose-stimulated insulin secretion

BACKGROUND

The purpose of this study was to construct an 'artificial beta cell' that can exhibit physiologic glucose-stimulated insulin secretion for the treatment of type 1 diabetes.

METHODS

Retroviral vector containing the glucokinase (GK) gene and mutated human proinsulin (mhPINS) gene was constructed. HepG2 cells were first infected with recombinant retrovirus carrying the GK and mhPINS genes, then selectively cultured with G418 to obtain the positive clones. GK and mhPINS gene transcription and expression were identified by radioimmunity, Western blot and RT-PCR techniques. Finally, the dose-response effect of glucose on insulin secretion from those HepG2 cells that expressed both GK and mhPINS genes was tested with HepG2 cells that only expressed the mhPINS gene as a control.

RESULTS

HepG2 cells with transferred GK and mhPINS genes were selectively cultured with G418 and the positive clones were obtained in 3 weeks. Four clones with GK and mhPINS gene expression were selected from 20 positive clones by radioimmunity and Western blot. We picked up one clone with a strong GK and mhPINS gene expression and named it clone Beta. In clone Beta, differences in insulin secretion at 0.5 and 0.75 mmol/L glucose concentrations were not significant (P>0.05) and differences in insulin secretion at 2.0, 3.0, 4.0, 5.0 and 6.0 mmol/L glucose concentrations were not significant (P>0.05), while there were significant differences in insulin secretion at other glucose concentrations(P<0.05). The artificial beta cell, clone Beta, obtained a glucose-stimulated insulin secretion with maximal insulin secretion at 1.75-2.00 mmol/L glucose concentrations.

DISCUSSION

An artificial beta cell that exhibits glucose-stimulated insulin secretion can be constructed successfully.

Low-dose lactulose produces a tonic contraction in the human colon

Lactulose (10-20 g day(-1)) is used to treat constipation. At this therapeutic dose, its effects on colonic motility remain unknown. Twenty-two healthy subjects swallowed a probe with an infusion catheter, six perfused catheters and a balloon connected to a barostat. Colonic phasic and tonic motor activity was recorded in fasting state. In group 1, four volunteers ingested 15 g lactulose and motility was recorded for 5 h after entry of lactulose into the caecum; in group 2, motility was recorded during (3 h) and 2 h after intracolonic infusion of isoosmotic and isovolumetric solutions containing sodium chloride alone (n = 9) or with 15 g lactulose (n = 9). In a last group of volunteers, isotopic colonic transit after ingestion of lactulose (10 g,n = 9) was assessed and compared with a control group (n = 17). Ingestion or intracolonic infusion of 15 g lactulose significantly decreased barostat bag volume (maximal decrease: 45 +/- 12% and 35 +/- 9% of basal value respectively). Phasic contractions remained unchanged. Tonic and phasic motility was unchanged by the isotonic and isovolumetric infusion of saline. Ingestion of lactulose significantly accelerated isotopic colonic transit time compared with the control group. We conclude that in healthy humans, 10-15 g ingestion or intracaecal infusion of lactulose produces a prolonged tonic contraction that may be involved in the laxative effect of lactulose.

Video capsule endoscopy for investigation of obscure gastrointestinal bleeding: feasibility, results, and interobserver agreement

BACKGROUND AND STUDY AIMS

The aim of the study was to assess the feasibility, diagnostic yield, and interobserver agreement of capsule endoscopy in the investigation of patients with obscure or occult gastrointestinal bleeding.

PATIENTS AND METHODS

A total of 64 consecutive patients with occult bleeding (31 %) or overt bleeding (69 %) were assessed using capsule endoscopy after negative upper and lower endoscopy and small-bowel radiology. The quality of visualization of the small-bowel mucosa was scored from 1 (poor) to 4 (excellent). Thirty video capsule recordings with normal or abnormal findings were blindly assessed by four independent endoscopists. Interobserver agreement was evaluated using the kappa index.

RESULTS

The small bowel was completely visualized in 57/64 patients (89 %). Incomplete small-bowel transit was most commonly due to prolonged gastric retention (five patients). The mucosa visualization scores (means) for the proximal, middle, and distal thirds of the small bowel were 3.7, 3.3, and 2.2 respectively. Visualization of the distal ileum was good (> or = 3) in 38 % and a bleeding site was found in 45 % of patients. Push-enteroscopy was also performed in 56 patients. The results of the two techniques were similar in 37 patients, capsule endoscopy was superior in 12 patients, and push-enteroscopy was superior in seven patients. Interobserver agreement was good for bleeding and for angiodysplasia, but poor for ulcers and tumors. Mean interobserver agreement was better among experienced endoscopists than among junior endoscopists.

CONCLUSIONS

Capsule endoscopy allowed the whole small intestine to be explored in 89 % of patients, with good visualization of the mucosa, except distally. Interobserver agreement was better among the experienced endoscopists and was better for red-colored abnormalities (bleeding and angiodysplasia) than for ulcers and tumors.

Alteration of the spinal modulation of nociceptive processing in patients with irritable bowel syndrome

BACKGROUND

Visceral hypersensitivity has been evidenced in patients with irritable bowel syndrome (IBS) but its mechanisms remain poorly elucidated. We investigated the spinal transmission of nociceptive signals in IBS patients by analysing the effects of rectal distensions on electromyographic recordings of the somatic nociceptive flexion (RIII) reflex, an objective index of spinal nociceptive processes.

METHODS

Fourteen IBS and 10 healthy volunteers were included in the study. Slow ramp (40 ml/min) and rapid phasic (900 ml/min, 10, 20, 30, and 40 mm Hg) rectal distensions were randomly performed while the RIII reflex evoked by electrical stimulation of the sural nerve at the ankle was continuously recorded from the ipsilateral biceps femoris.

RESULTS

In healthy volunteers, significant progressive inhibition of the RIII reflex was observed during slow ramp distension (61 (13)% of control values) while biphasic effects (facilitation and inhibition) were observed during rapid distensions. In contrast, in IBS patients, the RIII reflex was significantly facilitated during slow ramp distension (139 (15)% of control values) and inhibitions induced by rapid distensions were significantly reduced. Volumes of distension and rectal compliance were similar in both groups.

CONCLUSIONS

Our results provide direct evidence that a hyperexcitability of spinal nociceptive processes is present in a large subgroup of IBS patients.

Inflammatory bowel disease: what is new?

This article reviews a selection of 50 papers on inflammatory bowel disease published between April 2002 and August 2003. The new information and progress summarized here includes: the role of bacteria, their interaction with CARD15/NOD2 gene products and the modulating effects of probiotics; new imaging techniques, such as wireless capsule endoscopy and chromoendoscopy for detecting dysplasia, and fecal markers. It has not been possible to review every aspect of treatment, and the focus here is on factors capable of predicting the efficacy and tolerance of infliximab and new treatments, including natalizumab, thalidomide, cyclophosphamide and 6-thioguanine.

Alterations of the dominant faecal bacterial groups in patients with Crohn's disease of the colon

BACKGROUND AND AIMS

The colonic microflora is involved in the pathogenesis of Crohn's disease (CD) but less than 30% of the microflora can be cultured. We investigated potential differences in the faecal microflora between patients with colonic CD in remission (n=9), patients with active colonic CD (n=8), and healthy volunteers (n=16) using culture independent techniques.

METHODS

Quantitative dot blot hybridisation with six radiolabelled 16S ribosomal ribonucleic acid (rRNA) targeting oligonucleotide probes was used to measure the proportions of rRNA corresponding to each phylogenetic group. Temporal temperature gradient gel electrophoresis (TTGE) of 16S rDNA was used to evaluate dominant species diversity.

RESULTS

Enterobacteria were significantly increased in active and quiescent CD. Probe additivity was significantly lower in patients (65 (11)% and 69 (6)% in active CD and quiescent CD) than in healthy controls (99 (7)%). TTGE profiles varied markedly between active and quiescent CD but were stable in healthy conditions.

CONCLUSION

The biodiversity of the microflora remains high in patients with CD. Enterobacteria were observed significantly more frequently in CD than in health, and more than 30% of the dominant flora belonged to yet undefined phylogenetic groups.

Alterations of the dominant faecal bacterial groups in patients with Crohn's disease of the colon

BACKGROUND AND AIMS

The colonic microflora is involved in the pathogenesis of Crohn's disease (CD) but less than 30% of the microflora can be cultured. We investigated potential differences in the faecal microflora between patients with colonic CD in remission (n=9), patients with active colonic CD (n=8), and healthy volunteers (n=16) using culture independent techniques.

METHODS

Quantitative dot blot hybridisation with six radiolabelled 16S ribosomal ribonucleic acid (rRNA) targeting oligonucleotide probes was used to measure the proportions of rRNA corresponding to each phylogenetic group. Temporal temperature gradient gel electrophoresis (TTGE) of 16S rDNA was used to evaluate dominant species diversity.

RESULTS

Enterobacteria were significantly increased in active and quiescent CD. Probe additivity was significantly lower in patients (65 (11)% and 69 (6)% in active CD and quiescent CD) than in healthy controls (99 (7)%). TTGE profiles varied markedly between active and quiescent CD but were stable in healthy conditions.

CONCLUSION

The biodiversity of the microflora remains high in patients with CD. Enterobacteria were observed significantly more frequently in CD than in health, and more than 30% of the dominant flora belonged to yet undefined phylogenetic groups.

Cholecystokinin octapeptide increases rectal sensitivity to pain in healthy subjects

Hypersensitivity during rectal distension has been demonstrated in irritable bowel syndrome (IBS). Studies performed in animals and indirect data in humans suggest that cholecystokinin (CCK) could modulate visceral sensations. The aim of this study was to assess the effects of i.v. infused sulphated cholecystokinin octapeptide (CCK-OP) on rectal sensitivity in response to distension. In eight healthy subjects, rectal sensitivity and compliance were determined during a randomized double-blind study, with four sessions each separated by 7 days. Sensory thresholds and rectal compliance were assessed during slow-ramp (40 mL min-1) and rapid-phasic distensions (40 mL s-1, 5 mmHg stepwise, 1-min duration), and were compared before and during continuous infusion of either saline or CCK-OP at 5, or 20 or 40 ng kg-1 h-1. During rapid phasic distension but not during slow ramp distension, CCK-OP at 40 ng kg-1 h-1 produced a significant decrease in sensory thresholds compared with the basal period. Rectal compliance was not modified by any infusion. At pharmacological doses, CCK-OP decreases sensory thresholds during rapid phasic distension that may preferentially stimulate serosal mechanoreceptors, but has no effect on mucosal mechanoreceptors stimulated during slow ramp distensions. Modulation of rectal sensitivity by CCK could be implicated in the pathogenesis of the rectal hypersensitivity observed in IBS.

Probiotics and intestinal health effects: a clinical perspective

Probiotics are viable non-pathogenic micro-organisms which, when ingested, exert a positive influence on host health or physiology. We have critically analysed the evidence for the efficacy of specific probiotic strains in human gastrointestinal diseases. The best evidence can be obtained with randomised controlled trials which avoid bias. Good evidence has been obtained with several strains in the prevention or treatment of antibiotic-associated disorders, in the treatment (and to a lesser extent prevention) of gastroenteritis and acute diarrhoea and in the alleviation of lactose intolerance. We also analysed the recent randomised controlled trials performed in patients with Clostridium difficile or Helicobacter pylori, inflammatory bowel disease, irritable bowel syndrome, non-ulcer dyspepsia and colon cancer.

Long-term efficacy of combination therapy with interferon-alpha 2b and ribavirin for severe chronic hepatitis C in HIV-infected patients

BACKGROUND

We have assessed the long-term efficacy and safety of a combination therapy of interferon alpha-2b (IFN) and ribavirin (RBV) for the treatment of severe chronic hepatitis C in co-infected HIV-seropositive patients in an open prospective study.

METHODS

Fifty-one patients were treated for 12 months. Mean baseline CD4 cell count, alanine aminotransferase and aspartate aminotransferase were 412 +/- 232 x 106/l, 113 +/- 75 IU/l and 111 +/- 84 IU/l respectively. The mean Knodell score was 11.5 +/- 2.1 with 28 patients (55%) exhibiting histological evidence of active cirrhosis.

RESULTS

Fifteen (29%) patients discontinued the treatment prematurely because of adverse events. An end of treatment response (ETR) as defined by the lack of detectable hepatitis C virus (HCV) RNA in plasma at the end of treatment was achieved in 15 patients (29%). A sustained virological response (SVR), defined by the lack of detectable HCV RNA in plasma 6 months after completion of combination therapy, was achieved in 11 patients (21%). The HCV genotype 3a was associated with ETR and SVR (P = 0.002 and P = 0.003, respectively). HCV viraemia at baseline was lower in patients who achieved SVR and ETR than in those who did not (6.7 +/- 7.8 versus 24 +/- 26.7 x 10(6) genome equivalents/ml, P = 0.03 and 14.3 +/- 28.7 versus 22.5 +/- 23, P = 0.05, respectively).

CONCLUSION

Our results indicate that combination therapy with IFN and RBV is effective in approximately 20% of co-infected patients with severe liver disease.

Intraluminal modulation of gastric sensitivity to distension: effects of hydrochloric acid and meal

Conscious sensations in response to gut distensions may be modulated by temporospatial interactions among different stimuli. This study investigated whether symptoms induced by gastric distension may be modified by hydrochloric acid (HCl) gastric infusion and meal ingestion. In nine healthy subjects, fixed pressure (isobaric) and fixed volume (isovolumetric) distensions were performed during continuous (4 ml/min) intragastric saline or HCl infusion, during fasting and after meal ingestion, until the maximal distension step defined as discomfort or a predefined maximal volume. During fasting isobaric distensions, the maximal distension step was significantly decreased during HCl compared with saline. The intragastric volumes were not significantly different, but the wall tension was significantly lower during HCl than saline. HCl increased gastric compliance. Meal ingestion relaxed the stomach and decreased the pressure at the maximal distension step during saline, but HCl did not further decrease it compared with fasting. During isovolumetric distensions, HCl also increased gastric compliance, but in both fasted and fed states it did not modify the maximal distension steps. In conclusion, sensations in response to gastric isobaric distensions, but not to isovolumetric distensions, are influenced by gastric acid infusion and meal ingestion. The effects of HCl might be related to a sensitization of mucosal mechanoreceptors.

The antitumoral effect of the long-acting somatostatin analog lanreotide in neuroendocrine tumors

OBJECTIVE

Somatostatin analogs are the first-line drugs for controlling hormone-mediated symptoms of carcinoid tumors. Prospective and retrospective studies have suggested that somatostatin analogs also have antiproliferative activity. The octapeptide lanreotide is available in sustained-release form, obviating the need for daily injections.

METHODS

A total of 46 patients were enrolled in this open, prospective, phase II trial. They received lanreotide 30 mg i.m. every 14 days for 6 months when they had symptomatic carcinoid tumors, and lanreotide 30 mg i.m. every 10 days if they had nonsymptomatic tumors. Nonsymptomatic tumors were progressive before the start of the study. Tumor size was assessed every 3 months by means of computed tomography. The assessment was centralized and was made by an external panel.

RESULTS

In all, 30 patients had symptomatic neuroendocrine tumors and 16 had asymptomatic neuroendocrine tumors. Five patients in the group with symptomatic tumors and two in the group with nonsymptomatic tumors were considered not to be evaluable. The mean duration of treatment was 12 months in the group with symptomatic tumors and 13 months in the other group. Among the 39 evaluable patients, two objective responses were obtained, giving an objective response rate of 5% (one in the group with symptomatic tumors and one in the other group). Nineteen patients had no significant increase in their tumor size for a mean of 9.5 months.

CONCLUSIONS

Lanreotide is safe and well tolerated in patients with carcinoid tumors. It seems to have both symptomatic and antitumoral effects in this setting.

Rectal sensitivity assessed by a reflexologic technique: further evidence for two types of mechanoreceptors

We previously showed that slow-ramp rectal distensions induce graded inhibitions of the somatic nociceptive RIII reflex recorded from the lower limb, which correlated with both distension volume and visceral sensation. In contrast, rapid phasic rectal distensions induced facilitatory or biphasic effects (i.e., facilitations followed by inhibitions) depending on the level of distension. To examine the role of mucosal and serosal rectal mechanoreceptors in these viscerosomatic interactions, we analyzed, in six healthy volunteers, the effects of both types of rectal distension on the RIII reflex after topical application of lidocaine or placebo administered in a double-blind and crossover fashion. Inhibitions of the RIII reflex induced by both slow-ramp and rapid distensions were strongly reduced after administration of lidocaine but not after placebo. In contrast, facilitations of the RIII reflex observed during the initial phase of rapid distensions were not modified after lidocaine or placebo applications. These results suggest that inhibitions, but not facilitations, of the nociceptive RIII reflex triggered by rectal distensions depend preferentially on the activation of superficial mucosal receptors. This reflexologic technique might thus represent an interesting tool for studying the role of the different rectal mechanoreceptors involved in visceral sensations.

Selective expansion of intraepithelial lymphocytes expressing the HLA-E-specific natural killer receptor CD94 in celiac disease

BACKGROUND & AIMS

Celiac disease is a gluten-induced enteropathy characterized by the presence of gliadin-specific CD4(+) T cells in the lamina propria and by a prominent intraepithelial T-cell infiltration of unknown mechanism. The aim of this study was to characterize the subset(s) of intraepithelial lymphocytes (IELs) expanding during active celiac disease to provide insights into the mechanisms involved in their expansion.

METHODS

Flow-cytometric analysis of isolated IELs and/or immunohistochemical staining of frozen sections were performed in 51 celiac patients and 50 controls with a panel of monoclonal antibodies against T-cell and natural killer (NK) receptors. In addition, in vitro studies were performed to identify candidate stimuli for NK receptor expression.

RESULTS

In normal intestine, different proportions of IELs, which were mainly T cells, expressed the NK receptors CD94/NKG2, NKR-P1A, KIR2D/3D, NKp46, Pen5, or CD56. During the active phase of celiac disease, the frequency of CD94(+) IELs, which were mostly alphabeta T cells, was conspicuously increased over controls. In contrast, the expression of other NK markers was not modified. Furthermore, expression of CD94 could be selectively induced in vitro by T-cell receptor activation and/or interleukin 15, a cytokine produced by intestinal epithelial cells.

CONCLUSIONS

The gut epithelium favors the development of T cells that express NK receptors. In active celiac disease, there is a specific and selective increase of IELs expressing CD94, the HLA-E-specific NK receptor that may be related to T-cell receptor activation and/or interleukin 15 secretion.

Regional effects of cholecystokinin octapeptide on colonic phasic and tonic motility in healthy humans

The aim of this study was to assess in nine healthy subjects the effects of CCK octapeptide (CCK-8) on colonic tonic activity, measured by a barostat, and phasic activity, measured by manometry. On 2 consecutive days, recordings were performed in the unprepared proximal and distal colons during intravenous infusion of saline and CCK-8 at 5, 20, and 40 ng. kg-1. h-1. In the proximal colon CCK-8 induced, at the 20 and 40 ng. kg-1. h-1 doses, a tonic relaxation with an increase in barostat bag volume to 156 +/- 25 and 157 +/- 19% of basal (P < 0.01) and a decrease in phasic activity to 72 +/- 7 and 76 +/- 7% of basal (P < 0.01). In the distal colon, CCK-8 induced, at the 20 and 40 ng. kg-1. h-1 doses, a tonic relaxation (increase in intrabag volume to 133 +/- 12 and 149 +/- 15%, respectively; P < 0.01), whereas phasic activity increased (128 +/- 8 and 132 +/- 6%, respectively; P < 0.01). Effects of CCK-8 on tonic and phasic activities are different according to the colonic segment. Because meals induce colonic tonic contraction, our results suggest that CCK, as a hormone, is not an important mediator of the response of the colon to feeding in humans.

[Favorable outcome of a severe carcinoid cardiopathy after complete resection of the primary ovarian tumor]

Carcinoid heart disease induced by a primary ovarian carcinoid tumor is very uncommon but offers the opportunity to study its specific outcome. Indeed, unlike to other carcinoid syndromes that occur in the setting of liver metastasis, a complete removal of the primary carcinoid ovarian tumor is often possible in such cases. We report a case of severe carcinoid heart disease secondary to a carcinoid ovarian tumor. Its interest is related to the exhaustive assessment of the cardiopathy and its complete regression after removal of the ovarian tumor. This outcome emphasizes the need for a as complete as possible reduction of humoral secretions in carcinoid heart disease by medical or surgical therapies before discussing valve replacement surgery.

Effects of rectal distensions on nociceptive flexion reflexes in humans

We previously showed that gastric distension inhibits the somatic nociceptive flexion RIII reflex. To explore further the viscerosomatic interactions, we tested in the present study the effects of rectal distensions on RIII reflexes. Rapid and slow-ramp rectal distensions were performed in 10 healthy volunteers with an electronic barostat. The RIII reflex was continuously recorded from the lower limb during both types of distension and from the upper limb during rapid distensions. The visceral sensations were scored on a graded questionnaire. Rapid distensions facilitated the RIII reflex recorded from the lower limb, but at the highest distension level, facilitation was followed by inhibition. Slow-ramp distension induced gradual inhibition of the RIII reflex, which correlated with both distension volume and visceral sensation. RIII reflex recorded from the upper limb was also inhibited by rapid rectal distensions. Reflex inhibitions were probably related to the activation of pain modulation systems. One plausible explanation for the facilitatory effects, observed only at the lower limb, is the convergence of rectal and reflex afferents at the same levels of the spinal cord. The differential effects of rapid and slow-ramp distensions suggest the activation of two distinct populations of mechanoreceptors by these two modes of distension.

Tonic and phasic motor activity in the proximal and distal colon of healthy humans

In healthy humans, meals stimulate phasic and tonic motor activity in the unprepared distal colon. The response of the proximal colon remains unknown. In this study, we assessed the effect of a liquid meal on proximal and distal colonic motor activity. In 12 healthy volunteers, colonic tone and phasic motility were simultaneously recorded by using an electronic barostat and perfused catheters in the fasting state and in response to a 1,000-kcal meal. The meal significantly increased the phasic activity in the distal colon (230 +/- 46% of the basal value; P = 0.02) but not in the proximal colon (138 +/- 25% of the basal value; P = 0.2). The intrabag volume of the barostat was significantly more reduced in the distal than in the proximal colon (74 +/- 11 vs. 50 +/- 9% of the basal values, respectively; P = 0.04). We conclude that the postprandial response of the unprepared proximal colon is an immediate tonic contraction that is less pronounced than in the distal colon.

Local regulation of ileal tone in healthy humans

We previously showed that a meal induced, in the human terminal ileum, a delayed tonic relaxation, which could be related to the ileal delivery of meal residues and/or endogenous secretions released by a meal. In this study, we assessed the effects of some components of the ileal contents on its motor activity. In six healthy subjects, we studied ileal tonic and phasic motility in response to the infusion into the terminal ileum of different isotonic solutions: saline, glycochenodeoxycholic acid (GDCA), triglycerides, and short-chain fatty acids (SCFA). Tonic activity was not modified by saline, whereas it was significantly decreased by GDCA and triglycerides (maximal increase in intrabag volume 139 +/- 7% and 152 +/- 16%, respectively, P < 0.01), and significantly increased by SCFA (maximal decrease in intrabag volume 72 +/- 4%, P < 0.01). No significant change of phasic activity was evidenced with either solution. We conclude that 1) bile acids and triglycerides not absorbed in the more proximal gut could be involved in the ileal relaxation occurring after eating and 2) local stimulation of chemoreceptors is of importance in the regulation of ileal motility.

Ileal absorption of bile acids in patients with chronic cholestasis: SeHCAT test results and effect of ursodeoxycholic acid (UDCA)

The effect of cholestasis on ileal bile acid absorption is controversial in animal models (up- or down-regulation) and unknown in humans. We therefore studied values of the selena homotaurocholic acid (SeHCAT) test before and after long-term administration (>3 months, 13-15 mg/kg/day) of ursodeoxycholic acid (UDCA) in 27 patients with chronic cholestatic liver diseases (24 women, 3 men; mean age, 50 years; 24 primary biliary cirrhosis, 2 secondary biliary cirrhosis, 2 others). The control group consisted of 14 healthy volunteers. Seven-day SeHCAT percentage retention was identical in the 12 untreated cholestatic patients (serum bilirubin, 75+/-42 micromol/L, alkaline phosphatase, 4.2+/-1.0 N; mean+/-SEM) and in the control group (43.6+/-2.9 and 43.8+/-4.2%, respectively). In the 22 patients treated by UDCA for 38+/-8 months, SeHCAT percentage retention was 20.3+/-3.0%. In the seven patients with the SeHCAT test done before and after UDCA treatment (16+/-5 months), SeHCAT percentage retention decreased significantly under UDCA therapy (42.0+/-4.4 vs 19.4+/-4.1%; P < 0.02). We conclude that, in patients with chronic cholestasis (1) SeHCAT percentage retention is not altered-taken together with the known defect of biliary excretion, this lack of increase in SeHCAT percentage retention argues against up-regulation of bile acid ileal transport; and (2) UDCA treatment induces a decrease in the SeHCAT percentage retention-this effect may be related primarily to a decreased bile acid ileal absorption.

Effect of the kappa agonist fedotozine on perception of gastric distension in healthy humans

BACKGROUND AND AIM

Gastric hypersensitivity to mechanical distension has been observed in functional dyspepsia, but no drug is available that specifically acts on gastric afferent pathways to decrease gastric nociception. The aim of this study was to assess the effect of fedotozine, a synthetic ligand for peripheral kappa receptors, on human gastric sensitivity.

METHODS

Twenty-seven healthy volunteers were randomized to receive either fedotozine (30 mg t.d.s.) or a placebo, for 7 days. On day 7, the effects of fedotozine were tested on discomfort threshold and gastric compliance during graded isobaric and isovolumic distensions. In 16 of these subjects, the effect of this drug was tested on somatic sensitivity. In 10 other healthy volunteers the effect of fedotozine on gastric distension-induced inhibition of the RIII reflex, a process closely related to visceral sensitivity, was also studied.

RESULTS

During isobaric distensions, the discomfort threshold was significantly higher in subjects on fedotozine than in those on placebo (14.4 +/- 0.92 vs. 12.0 +/- 1.13 mmHg; P = 0.04). Compared to placebo, fedotozine did not modify gastric compliance and somatic sensitivity. Fedotozine also reduced the inhibition of the RIII reflex induced by gastric distension.

CONCLUSION

Fedotozine decreases gastric sensitivity to distension by exerting specific action on gastric afferent pathways.

Effect of glucose and lipids on intestinal absorption of sorbitol: role of gastric emptying

The aim of our study was to test the hypothesis that the better absorption of sorbitol when ingested with glucose could be related to a delayed gastric emptying. We tested the effect of the ingestion of glucose and lipids on the gastric emptying and intestinal absorption of sorbitol in six healthy volunteers, using gastric scintigraphy and hydrogen breath test. After an overnight fast, subjects ingested in random order, on 48-h test periods separated by at least one week, the following solutions: (a) 20 g sorbitol alone; (b) 20 g sorbitol and 20 g glucose; (c) 20 g sorbitol and 9 g lipids. Isotopic acquisitions were taken for 3 h following the ingestion of sorbitol labelled with 111Indium. Hydrogen concentration was measured in end-expiratory samples during 5 h, and the areas under the breath hydrogen curve, reflecting the amounts of sorbitol unabsorbed in the small bowel, were compared between periods. Mean area under the curve was 397 +/- 159 when sorbitol was ingested alone, and this was significantly lower when ingested with glucose or lipids (313 +/- 181 and 337 +/- 135, respectively; P < 0.05). The three curves of sorbitol gastric emptying differed significantly from each other, the gastric emptying being the slowest for sorbitol plus lipids, and the fastest for sorbitol taken alone. We found a positive correlation between the half-emptying time and the hydrogen areas under the curve (r = 0.46, P = 0.05). In conclusion, our study demonstrates that adding glucose or lipids to a solution of sorbitol slows the gastric emptying of sorbitol, resulting in a better intestinal absorption of sorbitol.

Treatment of the carcinoid syndrome with the longacting somatostatin analogue lanreotide: a prospective study in 39 patients

BACKGROUND

Somatostatin analogues effectively control flushing and diarrhoea in patients with the carcinoid syndrome. The octapeptide lanreotide is available in slow release form, which could eliminate the necessity of twice a day injections as with octreotide.

PATIENTS AND METHODS

39 patients with carcinoid syndrome were included in a prospective multicentre study. Patients received lanreotide 30 mg intramuscularly every 14 days for six months. The number and intensity of flushing episodes and bowel movements, urinary 5 hydroxy-indolacetic acid (5 HIAA) concentrations, and variations of tumour mass were recorded.

RESULTS

After one month of treatment, flushing episodes (median (range)) decreased significantly (3 (0.3-24) episodes per day v 1 (0-15), p = 0.04) and completely resolved in 39% of the patients. A significant decrease was seen in the number of bowel movements and discomfort related to diarrhoea. Urinary 5 HIAA concentrations were unchanged in 57% of the patients and decreased in 18%. After six months of treatment, the actuarial proportions of patients with at least a 50% decrease in the number of flushing episodes and bowel movements were 54% and 56%, respectively. Forty two per cent of the patients who were treated for six months had at least a 50% reduction in 5 HIAA values. No clear signs of regression of tumours were seen in any of the patients. Lanreotide was well tolerated despite transient mild pain or erythema at the injection site in 25% of the patients. Biliary lithiasis appeared in two patients after six months of lanreotide.

CONCLUSION

Lanreotide, 30 mg intramuscularly every other week, is an effective and convenient treatment in patients with the carcinoid syndrome.

[Anti-endomysium and anti-reticulin antibodies in adults with celiac disease followed-up in the Paris area]

OBJECTIVES

Circulating IgA class anti-endomysium and anti-reticulin antibodies are reliable serological markers for the diagnosis of coeliac disease. The aim of this study was to evaluate their diagnostic sensitivity and specificity, and their prevalence in a group of coeliac adults taking a gluten-free diet followed in Ile-de-France.

METHODS

One hundred and forty-five sera from 134 patients were examined for IgA and IgG anti-endomysium and anti-reticulin antibodies by indirect immunofluorescence. Sixty-eight patients were confirmed coeliacs; 8 patients with noncoeliac (unresponsive to a gluten-free diet) duodenal villous atrophy and 58 patients with no villous atrophy served as controls.

RESULTS

In active coeliac disease, the sensitivity of anti-endomysium and anti-reticulin antibodies was 88% and 50%, respectively. Their specificity was 100%: they were never detected in case of noncoeliac villous atrophy. Under a strict gluten-free diet, their prevalence was 7% and 0%, respectively.

CONCLUSION

In the studied population, the diagnosis accuracy of IgA anti-endomysium antibodies confirms their usefulness in screening and follow-up of coeliac disease. The absence of anti-endomysium and anti-reticulin antibodies in those cases with noncoeliac villous atrophy suggests that in the latter, different immunopathologic mechanisms, as compared with coeliac disease, are concerned.

Motor activity recorded in the unprepared colon of healthy humans

A manometric method was developed to study the motor activity in the unprepared human colon, and the results in eight healthy subjects were compared with those obtained in the same subjects after bowel cleansing with a non-absorbable solution containing polyethylene glycol 4000 (PEG). A tube assembly (4.5 m long, 12 lumen) was introduced through the nose and passed through the gastrointestinal tract. Two manometric recordings were performed one month apart, one without any preparation and the other after bowel cleansing with PEG. There was no obvious qualitative difference between the recordings performed in the uncleansed and PEG cleansed colon. Moreover, in the unprepared colon motility indices were close to those measured in the cleansed colon. The number of high amplitude propagated contractions (mean (SEM)) was, however, higher in the cleansed colon (8.6 (2.8) v 5.4 (1.8)/subject/9 h in the unprepared colon; p < 0.04). It is concluded that in healthy subjects taking a regular diet, motor activity is not different between the uncleansed and cleansed colon with PEG, except for the high amplitude propagated contractions, which occur more frequently in the cleansed colon.