Medical and psychological aspects of irritable bowel syndrome

To engineer an a non-islet cell capable of glucose-stimulated insulin secretion, a chinese hamster ovary cell line (CHO) was transfected with a mammalian expression vector carrying the human insulin cDNA (pCB/hINS). More proinsulin than insulin was released daily by the stably transformed cell line (CHO-INS). Examination of acid-ethanol extracts confirmed that both insulin and proinsulin were stored. Immunohistochemical analysis of the cells also showed that (pro)insulin was stored. Unlike beta cells, CHO-INS cells did not secrete insulin in response to glucose. To investigate this lack of effect, we examined whether transfection of GLUT2 cDNA, which is ordinarily not expressed in CHO-INS cells, would confer glucose-stimulated insulin secretion. Consequently, we have demonstrated that glucose regulated insulin release occurs in the CHO-INS-GLUT2 cell line and that glucose potentiates the insulin secretory response to non-glucose secretagogues.     

Lactose intolerance and irritable bowel syndrome

A recent study on lactose intolerance and irritable bowel syndrome has shown that subjective lactose intolerance is increased in patients with irritable bowel syndrome, despite no increase in the prevalence of lactose maldigestion.     

Psychological treatment of irritable bowel syndrome.

Although the symptoms of irritable bowel syndrome (IBS) are very prevalent in the general population, only the minority with IBS who seek treatment tend to be somewhat psychologically distressed. Four different classes of psychological treatment (brief psychodynamic psychotherapy, hypnotherapy, multicomponent cognitive-behavioral treatment regimens, and cognitive therapy) have each been shown to be superior to symptom monitoring or routine clinical medical care. Results with cognitive therapy and hypnotherapy have been replicated and have been found to be superior to attention-placebo control conditions. Benefits from psychological treatment have been maintained at up to 4 years. Close collaboration between psychologists and gastroenterologists is urged in the assessment and management of this patient population. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Abnormal colonic fermentation in irritable bowel syndrome

BACKGROUND: The cause of irritable bowel syndrome (IBS) is unknown. It may follow gastroenteritis and be associated with an abnormal gut flora and with food intolerance. Our study was designed to assess whether these factors were associated with colonic malfermentation. METHODS: We carried out a crossover controlled trial of a standard diet and an exclusion diet matched for macronutrients in six female IBS patients and six female controls. During the final 72 h on each diet, faecal excretion of fat, nitrogen, starch, and non-starch polysaccharide NSP was measured, and total excretion of hydrogen and methane collected over 24 h in a purpose-built 1.4 m3 whole-body calorimeter. Breath hydrogen and methane excretion were then measured for 3 h after 20 g oral lactulose. FINDINGS: The maximum rate of gas excretion was significantly greater in patients than in controls (2.4 mL/min IQR 1.7-2.6 vs 0.6, 0.4-1.1). Although total gas production in patients was not greater than in controls (median 527 mL/24 h IQR 387-660 vs 412, 234-507), hydrogen production was higher (332, 318-478 vs 162, 126-217, p=0.009). In patients, the exclusion diet reduced symptoms and produced a fall in maximum gas excretion (0.5 mL/min IQR 0.3-0.7). After lactulose, breath hydrogen was greater on the standard than on the exclusion diet. INTERPRETATION: Colonic-gas production, particularly of hydrogen, is greater in patients with IBS than in controls, and both symptoms and gas production are reduced by an exclusion diet. This reduction may be associated with alterations in the activity of hydrogen-consuming bacteria. Fermentation may be an important factor in the pathogenesis of IBS.     

Clinical economics review: irritable bowel syndrome

The ubiquitous nature of irritable bowel syndrome (IBS), coupled with a lack of good treatment options, has created the impression that the condition must represent a large drain on health-care resources. The literature certainly appears to support this view but is largely based on patients seen in referral centres (10-15%) and it may not be appropriate to extrapolate these data to the IBS population as a whole (85-90%). In addition to reviewing such literature that exists on the economics of IBS, this paper contains some new data, which suggest that the direct costs of the condition, certainly in the UK, may not be quite as high as has previously been assumed. This may be partly due to factors such as the low cost of the drugs used to treat the condition and the tendency for many patients to stop consulting because of disenchantment with the inadequacies of current therapy. Conversely, the indirect and intangible costs of the disorder appear to be much greater, but these burdens obviously do not have such an impact on those responsible for purchasing and providing health care for IBS sufferers. Paradoxically, if a new, effective therapy for IBS were forthcoming, the situation could change dramatically, especially if it involved a new drug. Any such agent would inevitably be more expensive than anything available today, leading to a potentially dramatic escalation in the direct costs of this disorder.     

Cognitive therapy for irritable bowel syndrome.

20 patients with irritable bowel syndrome (IBS) were randomly assigned either to intensive, individualized cognitive therapy (10 sessions over 8 wks) or to 8 wks of daily gastrointestinal (GI) symptom monitoring. Pre- to posttreatment evaluations showed significantly (p?=?.005) greater GI symptom reduction for those receiving cognitive therapy than for those in symptom monitoring. At posttreatment, 80% of the cognitive therapy group showed clinically significant improvement, whereas only 10% of the monitoring group showed this. Results held up well at a 3-month follow-up. Within the cognitive therapy group, GI symptom reductions correlated significantly with increases in positive and reductions in negative automatic thoughts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Constipation, diarrhea, and irritable bowel syndrome

Constipation, diarrhea, and irritable bowel syndrome are commonly encountered in the primary care practice. Most episodes of constipation and diarrhea are benign and self-limited. Patients with chronic constipation should undergo a screening evaluation to exclude organic disease, after which most can be managed successfully with dietary modification and fiber supplementation. The cause of chronic diarrhea usually can be discerned clinically, with irritable bowel syndrome, inflammatory bowel disease, and lactose intolerance being diagnosed most frequently. Irritable bowel syndrome is a functional gastrointestinal disorder characterized by abdominal pain and disordered defecation, which is successfully managed with a strong physician-patient relationship and periodic pharmacologic intervention.     

Is rectal pain sensitivity a biological marker for irritable bowel syndrome: psychological influences on pain perception

BACKGROUND & AIMS: Rectal pain sensitivity has been called a biological marker for irritable bowel syndrome, but this conclusion may be premature. This article is a critical review of the evidence for psychological influences on perception. METHODS: The world literature accessible through Index Medicus from 1973 to 1997 was systematically reviewed. RESULTS: Evidence favoring a biological basis for pain sensitivity is that two thirds of patients report pain at abnormally low thresholds of rectal distention despite normal somatic pain thresholds. Pain thresholds are not correlated with anxiety or depression. Evidence favoring psychological influences on perception is that patients with the irritable bowel syndrome rate even sham distentions as more painful, and when perception tests that minimize psychological influences are used, they have normal sensory thresholds. Also, stress alters sensory thresholds. Sensitization by repeated distention has been cited as evidence of a biological basis for hyperalgesia, but it is not unique to patients with irritable bowel. Brain imaging shows that different regions are activated by painful distention in patients with irritable bowel syndrome, but this is consistent with psychological influences on perception. CONCLUSIONS: Psychological factors influence pain thresholds in patients with the irritable bowel syndrome. Two cognitive traits, selective attention to gastrointestinal sensations and disease attribution, may account for increased pain sensitivity.     

Symptom relief with amitriptyline in the irritable bowel syndrome

An assay was developed for the specific detection of Escherichia coli O157 using PCR, because O serological cross-reactivities have been reported between E. coli O157 and some E. coli, other bacterial species. PCR amplification of E. coli O157 rfbE (Ec O157:H7) gene that is necessary for the expression of the O157 antigen, was performed for the identification of E. coli O157. All Shiga toxin-producing Escherichia coli (STEC) O157:H7 and O157:H, non-STEC O157 strains were positive, and other non-O157 E. coli strains were negative by PCR. All tested strains of other bacterial species, like Salmonella O30 and Citrobacter freundii which gave positive results with O157 detection kits, were negative by PCR. It is recommended that PCR amplification of O157 rfbE gene is one of the most specific method for E. coli O157 identification.     

Relaxation training as a treatment for irritable bowel syndrome

Although there have been many successful, controlled demonstrations of the clinical efficacy of multicomponent treatments for irritable bowel syndrome (IBS), in the present study we sought to evaluate a single component of many of these regimens, relaxation training. Eight IBS patients received a 10-session (over 8 weeks) regimen of abbreviated progressive muscle relaxation with regular home practice while 8 comparable patients merely monitored GI symptoms. Based on daily GI symptom diaries collected for 4 weeks before and 4 weeks after treatment (or continued symptom monitoring), the Relaxation condition showed significantly (p = .05) more improvement on a composite measure of primary GI symptom reduction than the Symptom Monitoring condition. Fifty percent of the Relaxation group were clinically improved at the end of treatment.     

Effect of sleep quality on symptoms of irritable bowel syndrome

A prospective, one-month diary study was conducted with 23 adult irritable bowel syndrome (IBS) patients in order to determine the relationship between IBS and the quality of sleep. Subjects were screened through history and diagnostic studies. Accepted patients then completed a daily diary of IBS symptoms and sleep quality. At baseline, most subjects (74%) characterized themselves as "poor sleepers." Using pooled time series analysis, the study found a significant correlation between morning IBS symptoms and the quality of the prior night's sleep (P < 0.001), a finding not previously reported in the literature. A less strong but still significant correlation (P < 0.05) was found between end of day IBS symptoms and the quality of sleep during the prior evening. Morning IBS symptoms seem to rise or fall in close association with the prior night's quality of sleep. The study supports the hypothesis that IBS symptoms are related to a disturbance in sleep.     

Toward a biobehavioral model of visceral hypersensitivity in irritable bowel syndrome

A review of records at a large urban methadone clinic revealed a substantial group of patients with treatment tenures of at least 6 months whose urinalysis results indicated continued regular use of opiates. In an attempt to characterize these "nonresponsive" patients and to identify their specific treatment needs, we compared them to a group of patients with comparable treatment tenures but whose urinalysis results indicated little or no recent illicit opiate use. Contrary to expectations, opiate use itself was virtually the only feature that clearly distinguished the two groups. "Responders" and "nonresponders" did not differ significantly on measures of psychosocial problem severity in any other area, nor did they differ in their treatment service utilization. Moreover, examination of admission data indicated that the two groups showed similar rates of improvement in the severity of their psychosocial problems in all seven measured areas. The implications of these results for treatment and clinic administration are discussed.     

Fecal characteristics contrasted in the irritable bowel syndrome and diverticular disease

A comparison has been made of the fecal characteristics in controls and patients with the irritable bowel syndrome and diverticular disease. No detectable difference was found in the fecal wet weight, dry weight, or total bile acid excretion in the four groups. A significant increase in the percentage of the water content of the stool was seen in the idiopathic diarrhea group with irritable bowel syndrome. Significantly less magnesium, potassium, and calcium was found in the stools of patients with diverticular disease and a similar trend was noted in patients with the spastic colon. These changes did not relate to the age of the patients. This suggests a common etiology for these disorders. The presence of increased water and primary bile acids in the feces of patients with idiopathic diarrhea suggests that this is a separate entity.     

Increased urine catecholamines and cortisol in women with irritable bowel syndrome

OBJECTIVES: There are few data on the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis in individuals with chronic GI symptoms. The current study was designed to describe and compare urine catecholamine (norepinephrine, epinephrine) and cortisol levels in women diagnosed with irritable bowel syndrome (IBS-patients), women who report similar symptom levels but had not sought health care services (IBS-nonpatients; IBS-NP), and asymptomatic (control) women. METHODS: Seventy-three women (24 IBS; 24 IBS-NP; 25 controls) were interviewed for demographic, GI, gynecological, and psychological data and then followed for two menstrual cycles with a daily health diary. Urine samples were obtained in the evening and morning at specific phases across two menstrual cycles. RESULTS: Women in the IBS group had significantly higher PM and AM urine norepinephrine levels. Urine epinephrine and cortisol levels were also generally higher in women with IBS. Differences in neuroendocrine indicators of arousal were not accounted for by differences in demographic variables, lifestyle characteristics, menstrual distress, or average daily measures of anxiety or depression. CONCLUSIONS: Increases in indicators of sympathetic nervous system activation in women seeking health care for IBS may reflect greater symptom distress or may contribute to increased symptom distress.     

Spectral analysis of heart rate variability in patients with irritable bowel syndrome

BACKGROUND: Autonomic dysfunction, both adrenergic and cholinergic, has been associated with the irritable bowel syndrome (IBS). The accuracy of the methods in use, however, has been limited by the need for active co-operation by the patients, with consequent difficulties in standardization. The aim of this study was to investigate the function of the autonomic nervous system in patients with IBS by using spectral analysis of the heart rate variability, an accurate method depending very little on patient cooperation. METHODS: Eighteen patients with IBS were compared with 36 sex- and age-matched controls. Spectral analysis of heart rate variability was performed to quantify sympathetic and parasympathetic nerve activity. RESULTS: The patients with IBS had significantly higher sympathetic activity than controls (P = 0.005). There was no significant (P = 0.308) increase in parasympathetic activity. There were no significant differences in heart rate or blood pressure between the patients and controls. CONCLUSION: Spectral analysis of heart rate variability has been used to assess the function of the autonomic nervous system in patients with IBS. IBS patients have significantly increased symphathetic activity, whereas parasympathetic activity does not differ from that of controls.