[Effects of electroacupuncture of different acupoints on changes of blood pressure and autonomic nerve system after colorectal distension in rats].

OBJECTIVE: To observe the influence of electroacupuncture (EA) of different acupoints on changes of mean arterial pressure (MAP), heart rate (HR) and heart rate variability (HRV) in colorectal distension (CRD) rats, so as to analyze the specificity of actions of acupoints in relieving visceral pain and regulating activities of the autonomic nerve system. METHODS: Forty-five Wistar rats were randomized into control, Zusanli (ST 36), non-acupoint, Neiguan (PC 6) and Taichong (LR 3) groups (n = 9/group). Under anesthesia, CRD was given to the rats by using an aerostat for 5 min. EA (2 Hz/15 Hz, 2 mA) was applied to bilateral ST 36, non-acupoint (1.0 cm lateral to ST 36), PC 6 and LR 3 for 15 min, respectively. Electrocardiogram of the cervico-chest lead was recorded by using a bioelectric amplifier, and MAP recorded by using a pressure transducer and an amplifier. Low frequency and high frequency of HRV were analyzed by Chart 5.0. RESULTS: Following CRD, the HR, MAP, LF and LF/HF levels increased significantly in all the 5 groups (P < 0.05), while HF had no apparent changes (P > 0.05). Compared with the control group, 5 min and 15 min after EA ,and 10 min after ceasing EA, MAP values of ST 36 and PC 6 groups were decreased obviously (P < 0.05). The HR values of ST 36 and PC 6 groups at 15 min after EA and 10 min after ceasing EA were decreased markedly in comparison with those of each of the other groups during CRD (P < 0.05). The LF levels of both ST 36 and PC 6 groups at 5 min after EA, and those of ST 36, PC 6 and LR 3 at 15 min after EA were significantly lower than those of control group (P < 0.05). LF/HF levels of ST 36 and PC 6 at 10 min after ceasing EA were obviously lower than those of control group (P < 0.05). No significant differences were found among ST 36, non-acupoint, PC 6 and LR 3 groups in HR, LF and LF/HF (P > 0.05). CONCLUSION: EA of ST 36 and PC 6 can suppress CRD-induced increase of MAP, HR and LF/HF, suggesting beneficial effects of EA in relieving visceral pain and mediating autonomic nerve system. The aforementioned effects of EA of LR 3 and non-acupoint are not obvious.

Idiopathic proximal hemimegacolon: radiologic findings and analyses of clinical and physiological characteristics.

BACKGROUND: Idiopathic megacolon with bowel dilatation only proximal to the splenic flexure is an uncommon and poorly characterized disease. This study aimed to identify the characteristics of idiopathic proximal hemimegacolon. METHODS: Five patients (2 males and 3 females) were diagnosed to have idiopathic proximal hemimegacolon and their radiologic, clinical, and physiological characteristics were reviewed. Hirschsprung's disease and other known causes of bowel dilatation were excluded by the presence of rectoanal inhibitory reflex and reviewing medical records. RESULTS: Mean age at diagnosis and symptom onset were 50.4 years and 47.2 years, respectively. Four patients presented with constipation, and all five patients showed abdominal distention and abdominal pain. Four patients were successfully treated and maintained only with laxatives and prokinetics without enema. Only one patient underwent surgery for intractable constipation. Mean maximal diameters of each segment of colons measured by computed tomography were 57.5 mm, 69.3 mm, 73.0 mm, 33.3 mm, 24.0 mm, and 27.3 mm for cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum, respectively. Colon transit time was delayed in four patients with mean value of 90.0 h. CONCLUSIONS: These results indicated that patients with idiopathic proximal hemimegacolon may be treated successfully only with medical therapy in most cases.

Novel concepts in the diagnosis, pathophysiology and management of idiopathic megabowel.

A proportion of patients with intractable constipation have persistent dilatation of the bowel, which in the absence of an organic cause is termed idiopathic megabowel (IMB). Whilst uncommon, this condition results in considerable morbidity. Traditional methods of identifying such patients are associated with inherent methodological limitations with anorectal manometry and contrast studies overestimating and underestimating the prevalence of the condition, respectively. Recently, controlled, pressure-based distension during fluoroscopic imaging has allowed more accurate identification of patients on the basis of a rectal diameter > 6.3 cm at the minimum distension pressure. Histopathological abnormalities of all three final effectors of sensorimotor function have been reported, although it remains unclear whether these changes are primary, secondary or epiphenomic. Physiological abnormalities of sensorimotor function, namely impaired perception of rectal distension and delayed colonic transit are well documented in patients with IMB. Further, the recent demonstration of two subgroups of patients, defined on the basis of rectal compliance, suggests the possibility that they differ pathophysiologically, although the clinical relevance of this distinction is uncertain. Surgery is performed when conservative therapy is ineffective or poorly tolerated. Numerous procedures have been attempted with variable success rates and significant mortality and morbidity. Surgery should preferably be performed in specialist centres given the relative infrequency with which such patients are encountered, and that they require comprehensive clinical, psychological and physiological evaluation preoperatively.

Surgical treatment of Chagasic megacolon by abdominal rectosigmoidectomy with immediate posterior end-to-side stapling (Habr-Gama technique).

PURPOSE: Various techniques have been used in the surgical treatment of Chagasic megacolon, including sympathectomy, sphincterotomy, anterior abdominal resection with high or low anastomosis, pull-through procedures, and Duhamel technique. However, results have not been consistently satisfactory, with reportedly high morbidity and mortality rates. The purpose of this study was to assess the technique and results of anterior rectosigmoidectomy with immediate posterior colorectal end-to-side stapled anastomosis for the treatment of Chagasic megacolon. METHODS: A prospective, noncontrolled study between 1989 and 2000 analyzed 49 patients with Chagasic megacolon. Preoperative barium enema confirmed Chagasic megacolon in all patients and preoperative anorectal manometry in 33 patients (67 percent). Rectal stump closure was undertaken by surgical stapling in 41 patients (84 percent); mechanical colorectal anastomosis was accomplished with a circular stapler in all patients. RESULTS: Symptoms of intestinal constipation ranged from 6 months to 40 years, Chagas' serology was positive in 98 percent of patients, 41 percent used bowel enemas for evacuation, and 71 percent had a history of fecaloma. The overall postoperative complication rate was 20 percent. Surgical complications occurred in 18 percent, 2 percent had nonsurgical complications, and there was no mortality. Postoperative barium enema was performed in 82 percent of cases, confirming the absence of disease. Postoperative anorectal manometry demonstrated normal resting pressure and rectal capacity; the inhibitory reflex remained absent and rectal sensitivity was increased. Ninety-three percent of patients were followed for more than 48 months, and all patients reported daily stool elimination without recurrence of constipation. CONCLUSIONS: The current study indicates that our technique is effective for surgical treatment of patients with Chagasic megacolon.

Oesophageal manometry in the evaluation of megacolon with onset in adult life.

BACKGROUND: Oesophageal motility is often impaired in patients with megaduodenum and other forms of intestinal pseudo-obstruction in which a visceral myopathy or neuropathy may be present. Idiopathic longstanding megacolon with onset in adult life is still a poorly defined entity, which may also be part of a more widespread motility disorder but in which oesophageal motility has not been yet systematically studied. AIMS: To assess oesophageal motility in patients with longstanding idiopathic megacolon with onset in adult life. PATIENTS: 14 consecutive subjects with idiopathic megacolon whose symptoms began after the age of 10 and a clinical history of 2-22 years. METHODS: Standard barium enema, water perfused oesophageal manometry, and also anorectal manometry. RESULTS: Oesophageal motility was impaired in five patients (36%; 95% confidence intervals 16 to 61%). Normal peristalsis was substituted by low amplitude multiple peaked simultaneous contractions in four subjects and by undetectable contractions in one. In three of them the lower oesophageal sphincter did not relax after swallows; in the same patients anal relaxation after rectal distension was also undetectable. All five patients with impaired oesophageal motility had a colonic dilatation sparing the rectum. Three of them reported constipation and a history of pesudo-obstruction and the other two only abdominal distension. CONCLUSIONS: Oesophageal manometry should be performed in patients with longstanding idiopathic megacolon with onset in adult life, in particular if the rectum is not dilated and even in absence of pseudo-obstruction. This simple test may disclose a more widespread visceral neuropathy or myopathy. Such a diagnosis helps to better understand the cause of the colonic dilatation and may be clinically relevant for treatment of the patients.

Intestinal transit and opaque enema study in chagasic mice

Relato de um estudo experimental realizado em camundongos brancos infectados com Trypanosoma cruzi. Foram estudados o trânsito intestinal e morfologia do cólon por meio de raio-X. Na fase subaguda, o trânsito intestinal apresentou-se normal. Nas fases aguda e crônica, havia entretanto, um retardo no tempo de evacuaçäo. Num dos 12 animais, o enema opaco revelou a presença de megacolon

Intestinal transit and opaque enema study in chagasic mice.

The report concerns as experimental study utilizing thirty-three mice inoculated subcutaneously with 1000 blood forms of Trypanosoma cruzi. Intestinal transit and morphology of colon were studies by means of X-rays. In subacute stage intestinal transit was normal. In chronic stages the mice displayed a delay in evacuation time. In one out of 12 animals the opaque enema documented the existence of megacolon.

Hypothyroidism impairs colonic motility and function. An experimental study in the rat.

Hypothyroidism (HT) may be associated with either megacolon or severe constipation that mimics Hirschsprung's disease. The exact nature of this relationship is unclear. This report evaluates colonic motility in experimental HT. HT was produced by a total thyroidectomy in 20 male Sprague-Dawley rats (200-300 g). Ten of the HT rats were given thyroxin (30 micrograms/kg/day i.p. for 4 weeks) for a replacement study (RS). Ten sham operated rats (SH) and 50 unoperated rats (UN) were studied as controls. HT was documented at 4 weeks following total thyroidectomy by measuring serum T3, T4 uptake, and TSH. At four to 6 weeks the animals were evaluated for several studies concerning colonic motility. Normal weight gain was significantly impaired under HT. In addition, daily stool volume as well as the number of fecal pellets were significantly reduced in HT. A barium enema showed a dilated colon in HT with an increase of recto-colonic ratio. Anal canal pressure was relatively low in HT. HT rats had a decreased frequency of rhythmic colonic activity (cycle/min) (HT: 10.22 +/- 2.16 vs. UN: 18.09 +/- 4.79, SH: 15.88 +/- 3.92, p less than 0.001). RS rats showed a recovery of rhythmic frequency (15.56 +/- 4.46, p less than 0.001). A positive recto-anal reflex was seen in all UN and SH rats, but only 40% in HT and 80% in RS. The effect of isoproterenol on anal canal pressure was significantly less in HT. Colonic transit at 4 hours was considerably slower in HT (HT: 29.0 +/- 21.0% vs. US: 60.4 +/- 18.3%, SH: 58.7 +/- 14.8%, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of anorectal motility measurements in the management of adult megacolon.

Anorectal motility was studied in 23 patients with adult megacolon. A balloon was used for rectal distension, and electrical signals from the anal canal or rectal mucosa were monitored with a silver/silver chloride electrode. Intraluminal pressure was measured by a pressure transducer linked to the vicinity of the electrode via a polythene tube. Responses to rectal distension provided a means of distinguishing patients with adult Hirschprung's disease from ones with idiopathic megacolon. Some patients with the latter condition showed an elevation of mean anal canal pressure relative to that in normal subjects. There was no statistically significant difference in slow-wave frequency in the anal canal between patients and adult megacolon and normal subjects. The fall in anal canal pressure associated with rectal distension was correlated with a decline in the amplitude of slow-wave electrical activity. The measurement of anorectal motor parameters was of value in the management of adult megacolon.

Megacolon at high altitude.

Megacolon occurs frequently in high altitude areas. This report describes observations made in 60 cases seen in La Paz, Bolivia (3,600 meters above sea level). Motility of both the large and small bowel was found to be increased and the feces had a low pH. No histologic abnormalities were noted in the nervous plexus or smooth muscle. It is assumed that megacolon in these circumstances is acquired and not congenital.

Anorectal manometry for evaluating defecation disorders.

Anorectal manometry is a valuable tool in the differential diagnosis of disorders of defecation. While especially useful in differentiating between functional constipation and Hirschsprung's disease and thus reducing in many children the need for barium enema and rectal biopsy, anorectal manometry can be a practical adjunct in the diagnosis and management of patients of all ages with constipation and/or fecal soiling due to a wide range of congenital and acquired disease.

The barium-enema examination and rectal manometry in Hirschsprung disease.

Barium-enema studies and rectal manometry were clearly shown complementary in diagnosing Hirschsprung disease. Of 27 patients studied, 19 had positive barium-enema and rectal manometric studies and were proved histologically to have Hirschsprung disease. Three had positive barium-enemas but normal rectal manometric studies in the first 10 days of life; later manometric studies were positive, and all 3 were subsequently proved to have Hirschsprung disease. Three patients had negative barium-enema and positive manometric studies and were proved to have low segment Hirschsprung disease. If both studies indicate the disease, rectal biopsy is not necessary before surgery.

Ultrastructural and histochemical studies of murine megacolon.

The myenteric plexus of the colon was studied ultrastructurally in a colony of an Ls Ls strain of mice manifesting a piebald coat color mutation associated with a high incidence of genetically determined aganglionic megacolon. Ultrastructural studies were histochemically supplemented by the Maillet technic and stains for acetylcholinesterase and catecholamines. The development of megacolon did not appear to require total aganglionosis, since ostensibly aganglionic areas contained rare ganglion cells. In the distal narrowed segment, both cholinergic and adrenergic fibers in the muscularis, submucosa and mucosa were somewhat reduced. In the mouse, the dilated portion showed an abrupt increase in adrenergic fibers. These findings are related to the pathophysiology of the disorder. The increasing degenerative changes seen in myenteric plexus structures from the fetus to adult suggest that aganglionic megacolon may be an abiotrophy, wherein the congenitally deficient myenteric plexus may be unusually predisposed to postnatal injury and degeneration.