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Biomedical subjects

Satish S C Rao

Publications and source records attributed to Satish S C Rao.

At least 19 recordsLinked to original sources
PubMed2006

Influence of body position and stool characteristics on defecation in humans.

BACKGROUND: Whether defecation is influenced by body position or stool characteristics is unclear. AIM: We investigated effects of body position, presence of stool-like sensation, and stool form on defecation patterns and manometric profiles. METHODS: Rectal and anal pressures were assessed in 25 healthy volunteers during attempted defecation either in the lying or sitting positions and with balloon-filled or empty rectum. Subjects also expelled a water-filled (50 cc) balloon or silicone-stool (FECOM) either lying or sitting and rated their stooling sensation. RESULTS: When attempting to defecate in the lying position, a dyssynergic pattern was seen in 36% of subjects with empty rectum and 24% with distended rectum. When sitting, 20% showed dyssynergia with empty rectum and 8% with distended rectum. More subjects (p < 0.05) showed dyssynergia in lying position. When lying, 60% could not expel balloon and 44% FECOM. When sitting, fewer (p < 0.05) failed to expel balloon (16%) or FECOM (4%). FECOM expulsion time was quicker (p < 0.02). Stool-like sensation was more commonly (p < 0.005) evoked by FECOM than balloon. CONCLUSIONS: In the lying position, one-third showed dyssynergia and one-half could not expel artificial stool. Whereas when sitting with distended rectum, most showed normal defecation pattern and ability to expel stool. Thus, body position, sensation of stooling and stool characteristics may each influence defecation. Defecation is best evaluated in the sitting position with artificial stool.

Adult↗
PubMed2006

Pathophysiology and role of biofeedback therapy in solitary rectal ulcer syndrome.

BACKGROUND: Solitary rectal ulcer syndrome (SRUS) is a behavioral disorder whose pathophysiology is incompletely understood. Likewise, its treatment, particularly the role of biofeedback therapy (BT) is unclear. AIM: To evaluate anorectal function and morphology and to assess efficacy of BT. METHODS: Eleven patients (8f) with refractory SRUS underwent symptom assessments, anorectal manometry, defecography, balloon expulsion test, and sigmoidoscopy. Physiological tests were also performed in 15 (11f) healthy controls. Subsequently, SRUS patients underwent biofeedback treatment. Symptoms and manometry were reassessed. RESULTS: Nine (82%) patients exhibited dyssynergia ( p < 0.001). Rectal sensory thresholds were decreased (p < 0.04). After biofeedback, straining effort and stool frequency decreased ( p < 0.05), and bowel satisfaction score (VAS) improved ( p < 0.001). Digital maneuvers were discontinued by all five patients and bleeding stopped in 56%. The defecation index increased ( p < 0.05), dyssynergia normalized, and balloon expulsion time decreased ( p < 0.05). There was complete healing in 4 (36%), > or =50% healing in 2 (18%), and <50% healing in 4 (36%) patients. CONCLUSIONS: SRUS associated with excessive straining, digital disimpaction, rectal hypersensitivity, dyssynergic defecation, and prolonged evacuation. BT may improve symptoms and anorectal function and facilitate healing.

Adolescent↗
PubMed2006

Diagnostic testing in patients with chronic constipation.

During the past few years, significant developments have taken place in the understanding and diagnosis of defecation disorders. Several innovative manometric, neurophysiologic, and radiologic techniques have been discovered, which have improved the accuracy of identifying the neuromuscular and pathophysiologic mechanisms of chronic constipation. Such approaches have led to improved management of these patients. In this review, we summarize and highlight recent advances in the utility of diagnostic testing of chronic constipation.

Chronic Disease↗
PubMed2006

Defecation disorders: neuromuscular aspects and treatment.

Chronic constipation and fecal incontinence affect 20% of the population and are more prevalent in women, the elderly, those of lower socioeconomic status, and nursing home residents. These disorders pose a significant economic burden and affect quality of life. During the past decade, significant strides have been made in the understanding and treatment of defecation disorders, which have led to real advances in the management of these disorders. These treatments include biofeedback therapy, tegaserod, and lubiprostone for chronic constipation.

Biofeedback, Psychology↗
PubMed2005

Investigation of fundo-antral reflex in human beings.

AIM: To examine the sensory and motor response(s) of the stomach following fundic distention and to assess whether cholinergic mechanisms influence these responses. METHODS: Fundic tone, gastric sensory responses and antral motility were evaluated in eight healthy volunteers after a probe with two sensors was placed in the antrum and a highly compliant balloon in the fundus. Isobaric balloon distentions were performed with a barostat. Study was repeated in six volunteers after intravenous atropine was given. RESULTS: Fundic distention induced large amplitude antral contractions in all subjects. The area under the curve was higher (P<0.05) during fundic distention. First sensation was reported at 12+/-4 mmHg, moderate sensation at 18+/-4 mmHg and discomfort at 21+/-4 mmHg. Discomfort was associated with a decrease in antral motility. After atropine was given, the area under the curve of pressure waves and fundic tone decreased (P<0.05). Sensory thresholds were not affected. CONCLUSIONS: Fundic balloon distention induces an antral motor response, the fundo-antral reflex, which in part may be mediated by cholinergic mechanisms.

Adult↗
PubMed2005

Efficacy and safety of traditional medical therapies for chronic constipation: systematic review.

OBJECTIVES: Constipation is common, and its treatment is unsatisfactory. Although many agents have been tried, there are limited data to support their use. Our aim was to undertake a systematic review of the efficacy and safety of traditional medical therapies for chronic constipation and to make evidence-based recommendations. METHODS: We searched the English literature for drug trials evaluating treatment of constipation by using MEDLINE and PUBMED databases from 1966 to 2003. Only studies that were randomized, conducted on adult subjects, and published as full manuscripts were included. Studies were assigned a quality score based on published methodology. Standard forms were used to abstract data regarding study design, duration, outcome measures, and adverse events. By using the cumulative evidence of published data for each agent, recommendations were made regarding their use following the United States Preventive Services Task Force guidelines. RESULTS: Good evidence (Grade A) was found to support the use of polyethylene glycol (PEG) and tegaserod. Moderate evidence (Grade B) was found to support the use of psyllium, and lactulose. There was a paucity of quality data regarding many commonly used agents including milk of magnesia, senna, bisacodyl, and stool softeners. CONCLUSIONS: There is good evidence to support the use of PEG, tegaserod, lactulose, and psyllium. Surprisingly, there is a paucity of trials for many commonly used agents. These aspects should be considered when designing trials comparing new agents with traditional therapies because their use may not be well validated.

Adult↗
PubMed2005

Clinical utility of diagnostic tests for constipation in adults: a systematic review.

BACKGROUND AND AIMS: Because symptoms alone do not identify pathophysiology or differentiate subgroups of constipation, diagnostic tests are generally recommended. However, their utility is not known. We performed a systematic review of diagnostic tests commonly used in constipation. METHODS: We searched the English literature using MEDLINE and PUBMED databases from 1966 to 2004 for studies in adults published as full manuscripts whose methodological quality was above a minimum score. RESULTS: No studies assessed the routine use of blood tests or abdominal x-ray. One retrospective endoscopic study showed that cancer and polyp detection rate was comparable to historical controls. Two studies of barium enema were unhelpful in diagnosis of constipation. Physiological studies showed differences in study population, methodology, and interpretation, and there was no gold standard. Ten colonic transit studies showed prevalence of 38-80% in support of slow transit constipation. Nine anorectal manometry studies showed prevalence of 20-75% for detecting dyssynergia. Nine studies of balloon expulsion showed impaired expulsion of 23-67%. Among 10 defecography studies, abnormalities were reported in 25-90% and dyssynergia in 13-37%. CONCLUSIONS: Evidence to support the use of blood tests, radiography, or endoscopy in the routine work up of patients with constipation without alarm features is lacking. Colonic transit, anorectal manometry, and balloon expulsion tests reveal physiologic abnormalities in many selected patients with constipation, but no single test adequately defines pathophysiology. Large, well-designed, prospective studies are required to examine the utility of these tests.

Adult↗
PubMed2004

Pathophysiology of adult fecal incontinence.

Fecal incontinence occurs when the normal anatomy or physiology that maintains the structure and function of the anorectal unit is disrupted. Incontinence usually results from the interplay of multiple pathogenic mechanisms and is rarely attributable to a single factor. The internal anal sphincter (IAS) provides most of the resting anal pressure and is reinforced during voluntary squeeze by the external anal sphincter (EAS), the anal mucosal folds, and the anal endovascular cushions. Disruption or weakness of the EAS can cause urge-related or diarrhea-associated fecal incontinence. Damage to the endovascular cushions may produce a poor anal "seal" and an impaired anorectal sampling reflex. The ability of the rectum to perceive the presence of stool leads to the rectoanal contractile reflex response, an essential mechanism for maintaining continence. Pudendal neuropathy can diminish rectal sensation and lead to excessive accumulation of stool, causing fecal impaction, mega-rectum, and fecal overflow. The puborectalis muscle plays an integral role in maintaining the anorectal angle. Its nerve supply is independent of the sphincter, and its precise role in maintaining continence needs to be defined. Obstetric trauma, the most common cause of anal sphincter disruption, may involve the EAS, the IAS, and the pudendal nerves, singly or in combination. It remains unclear why most women who sustain obstetric injury in their 20s or 30s typically do not present with fecal incontinence until their 50s. There is a strong need for prospective, long-term studies of sphincter function in nulliparous and multiparous women.

Adult↗
PubMed2004

Dyssynergic defecation: demographics, symptoms, stool patterns, and quality of life.

To understand the nature of bowel disturbance in patients with dyssynergia, we prospectively examined demographics, stool patterns, and quality of life by administering a 31-item questionnaire to 120 patients who fulfilled symptomatic and manometric criteria for dyssynergia (Rome II). Data from 118 subjects (M/F = 27/91) was analyzed. Eighty four percent of patients reported excessive straining, and 76% reported feeling of incomplete evacuation; 9.7% had no urge to defecate. Abdominal bloating was reported by 74%. More women than men reported infrequent bowel movements and need to strain excessively (P < 0.05). Forty eight percent of patients, more women (P < 0.05) than men used digital maneuvers to evacuate. Hard stools was reported by 60% of women and 41% of men. Sexual abuse was reported by 22%; 21% were women (P = 0.02). Physical abuse was reported by 32%. Bowel problem adversely affected family life in 33%, sexual life in 56%, work life in 69% and social life in 76% of patients. Most patients with dyssynergia reported an excessive need to strain, feeling of incomplete evacuation and abdominal bloating and one half used digital maneuvers. It significantly affected quality of life, particularly in women.

Adolescent↗
PubMed2004

Investigation of the pathophysiology of fecal seepage.

BACKGROUND AND AIM: Unintentional seepage of stool without awareness is common but its pathophysiology is poorly understood. Our aim was to examine the underlying mechanism(s) for fecal seepage. METHODS: We evaluated prospectively 25 patients with fecal seepage, by performing anorectal manometry, balloon expulsion, saline infusion, pudendal nerve latency tests, and symptom assessments and compared their data with 26 fecal incontinence patients and 43 healthy controls. RESULTS: Predisposing factors for fecal seepage were back injury (7), obstetric injury (6), hemorrhoidectomy (3), pelvic radiotherapy (1), and unknown (8). In the seepage group, the resting and squeeze sphincter pressures were lower (p < 0.02) than healthy controls, but higher (p < 0.002) than incontinent group. During straining, the intrarectal pressure and defecation index were lower (p < 0.05) in the seepage group compared to controls; 72% showed dyssynergia and balloon expulsion time was prolonged (p < 0.01). Threshold for first rectal sensation was impaired (p < 0.002) in the seepage group compared to controls and incontinent group. The seepage group retained more (p < 0.001) saline than the incontinent group but pudendal nerve latency time was impaired (p < 0.05) in both patient groups compared to controls. CONCLUSIONS: Anal sphincter function and rectal reservoir capacity were relatively well preserved but most patients with seepage demonstrated dyssynergia with impaired rectal sensation and impaired balloon expulsion. Thus, incomplete evacuation of stool may play a significant role in the pathogenesis of seepage.

Adult↗
PubMed2004

Ambulatory 24-hour colonic manometry in slow-transit constipation.

BACKGROUND: The colonic neuromuscular dysfunction in patients with constipation and the role of colonic manometry is incompletely understood. AIM: To study prolonged colonic motility and assess its clinical significance. METHODS: Twenty-four-hour ambulatory colonic manometry was performed in 21 patients with slow-transit constipation and 20 healthy controls by placing a 6-sensor solid-state probe up to the hepatic flexure. Quantitative and qualitative manometric analysis was performed in 8-h epochs. Patients were followed up for 1 yr. RESULTS: Constipated patients showed fewer pressure waves and lower area under the curve (p < 0.05) than controls during daytime, but not at night. Colonic motility induced by waking or meal was decreased (p < 0.05) in patients. High-amplitude propagating contractions (HAPCs) occurred in 43% of patients compared to 100% of controls and with lower incidence (1.7 vs 10.1, p < 0.001) and propagation velocity (p < 0.04). Manometric features suggestive of colonic neuropathy were seen in 10, myopathy in 5, and normal profiles in 4 patients. Seven patients with colonic neuropathy underwent colectomy with improvement. The rest were managed conservatively with 50% improvement at 1 yr. CONCLUSIONS: Patients with slow-transit constipation exhibited either normal or decreased pressure activity with manometric features suggestive of colonic neuropathy or myopathy as evidenced by absent HAPC or attenuated colonic responses to meals and waking. In refractory patients, colonic manometry may be useful in characterizing the underlying pathophysiology and in guiding therapy.

Adult↗
PubMed2003

Diagnostic testing in fecal incontinence.

Fecal incontinence is a common problem that disproportionately affects women and the elderly and has a significant impact on the quality of life. Incontinence is often multifactorial. Anorectal manometry, anal endosonography, magnetic resonance imaging, pudendal nerve latency, and electromyography provide morphologic and physiologic assessments of the internal and external anal sphincters, rectal motor and sensory function, rectal compliance, and rectoanal reflexes. This information, in concert, provides clues to the pathophysiology of fecal incontinence and may help to guide medical, surgical, or biofeedback therapy. These tests have also been used to assess the effectiveness of the therapeutic modalities. No data are available on the cost-effectiveness of diagnostic testing in fecal incontinence. Newer techniques, including electrophysiologic testing and morphologic imaging of the anorectum, are being pursued.

Diagnosis, Differential↗
PubMed2003

Constipation: evaluation and treatment.

Constipation is a common clinical problem that comprises a constellation of symptoms that include excessive straining, hard stools, feeling of incomplete evacuation, use of digital maneuvers, or infrequent defecation. Although many conditions, such as metabolic problems, fiber deficiency, anorectal problems, and drugs, can cause constipation, when excluded functional constipation consists of two subtypes: slow-transit constipation and dyssynergic defecation. Some patients with irritable bowel syndrome may exhibit features of both types of constipation. The Rome criteria for functional constipation together with modifications proposed here for dyssynergic defecation may serve as useful guidelines for making a diagnosis. Recent advances in technology, together with a better understanding of the underlying mechanisms, have led to real progress in the diagnosis of this condition. Management options are limited, however, and evidence to support these treatments is only modest. The treatment is primarily medical; surgical options should be reserved for refractory disease and after careful diagnostic work-up. Although laxatives remain the mainstay of therapy, prokinetics that are colon-selective are optimal for treating patients with slow-transit constipation, but they are not yet available for clinical use. Recent controlled trials, however, are promising. Biofeedback therapy is the preferred treatment for patients with dyssynergia, but is not widely available. In the near future, user-friendly biofeedback programs including home therapy may facilitate wider use of these methods for patients with dyssynergic defecation.

Biofeedback, Psychology↗
PubMed2003

Fructose intolerance: an under-recognized problem.

OBJECTIVES: Although the role of lactose intolerance in the pathogenesis of abdominal symptoms is well known, the role of fructose intolerance is unclear. Our aims were 1) to examine the prevalence of fructose intolerance in patients with unexplained abdominal symptoms, and 2) to explore whether fructose concentration influences fructose breath test. METHODS: Over 2 yr, patients with unexplained symptoms answered questionnaires and underwent fructose breath tests. Patients received 50 g fructose in 150 ml water (33% solution). Breath samples were collected for hydrogen and methane. In a second study, breath test was performed after giving either 10%, 20%, or 33% fructose solution. Data were analyzed retrospectively. RESULTS: A total of 183 patients (50 male, 133 female) had breath tests, of whom 134 (73%) were positive. Among these, 119 (89%) had elevated H(2), and 15 (11%) had elevated CH(4) or both gases. Questionnaires showed that flatus (83%), pain (80%), bloating (78%), belching (70%), and altered bowel habit (65%) were the most common symptoms. Breath test reproduced symptoms in 101 patients (75%). In the second study, 14/36 (39%) tested positive with a 10% solution, 23/33 (70%) with a 20% solution, and 16/20 (80%) with a 33% solution (10% versus 20% or 33%, p < 0.01). CONCLUSIONS: Fructose intolerance may cause unexplained GI symptoms. The higher yield of positive tests in our initial study may be due to referral bias or testing conditions; lower test dose produced a lower yield. Nonetheless, recognition and treatment of fructose intolerance may help many patients.

Adult↗
PubMed2003

Effects of gender and age on esophageal biomechanical properties and sensation.

OBJECTIVES: The effects of gender and age on human esophageal function is poorly defined. Our aim was to investigate the sensory perception and the biomechanical properties of the esophagus both at the smooth muscle and the striated muscle segments in age- and gender-matched healthy subjects. Eleven older individuals (five men and six women, aged 55-82 yr) and 11 younger healthy individuals (five male and six female, aged 22-45 yr) participated in this study. METHODS: Graded balloon distentions were performed at the striated muscle and the smooth muscle segments of the esophagus in a random order using impedance planimetry. Impedance planimetry facilitated simultaneous assessments of the biomechanical properties and sensory perception. RESULTS: We found that both at the striated and smooth muscle segments, the cross-sectional area, circumferential wall tension-strain relationship and the sensory thresholds were similar between men and women. In contrast, at both of these segments, the cross-sectional area was larger (p < 0.05), the circumferential wall tension-strain association had shifted significantly (p < 0.05) to the left (i.e., the wall was stiffer), and the median thresholds for discomfort and pain were higher (p < 0.05) in older subjects. The biomechanical properties and thresholds for sensory perception also varied between the two esophageal segments. CONCLUSIONS: Aging was associated with a larger lumen and a stiffer but less sensitive esophageal wall. Thus, aging but not gender may influence esophageal function.

Adult↗
PubMed2003

Neurotrophin-3 improves functional constipation.

OBJECTIVE: Neurotrophin-3 (NT-3) is a neurotrophic factor involved in the growth, development, and function of the nervous system. In preliminary studies, s.c. recombinant methionyl-human NT-3 enhanced transit throughout the GI tract and increased stool frequency in normal and constipated subjects. Our aim was to assess 1) the dose-related effects of NT-3 on bowel function, colon transit, and symptoms of chronic constipation, and 2) its safety. METHODS: This was a double-blind, randomized, placebo-controlled phase II study. A total of 107 patients with a diagnosis of functional constipation (Rome II criteria) were randomized to receive 4 wk of double blind, s.c. injections of either placebo, 3 mg, or 9 mg NT-3 once per week (qW) or three times per week (TTW); or 9 mg NT-3 TTW for 1 wk, then qW. The primary endpoint was the change in number of spontaneous, complete bowel movements per week. Colon transit was assessed before and at end of treatment. RESULTS: Compared with placebo, patients who received 9 mg NT-3 TTW showed significant increases in frequency of spontaneous, complete bowel movements and total bowel movements, as well as dose-related softening of stool and improved ease of passage. The number of days per week without a bowel movement also decreased, colon transit improved, as did constipation-related symptoms. Weekly dosing was ineffective. Transient injection-site reactions, seen in one third of patients receiving NT-3 TTW, were the most frequent adverse event. CONCLUSIONS: NT-3, administered TTW, increased stool frequency, enhanced colon transit, and improved symptoms of chronic constipation. NT-3 seems to be a novel, safe, and effective agent for the treatment of functional constipation.

Adolescent↗