Search PubMed⌕ Search

Biomedical subjects

M E Williamson

Publications and source records attributed to M E Williamson.

At least 19 recordsLinked to original sources
PubMed2001

Altered GLUT1 and GLUT3 gene expression and subcellular redistribution of GLUT4: protein in muscle from patients with acanthosis nigricans and severe insulin resistance.

Multiple isoforms of glucose transporters are found in muscle, the tissue that normally accounts for 85% of insulin-stimulated glucose uptake. Glucose uptake into muscle cells in the fasting state is mediated primarily by GLUT1 and GLUT3 glucose transporters, whereas postprandial (insulin-stimulated) and exercise-related increments in muscle glucose uptake are mediated primarily by GLUT4. To determine if glucose transporters are abnormally expressed in muscle from insulin-resistant subjects, muscle samples were obtained from 10 normal subjects and 6 obese, nondiabetic subjects with severe insulin resistance and acanthosis nigricans. Both GLUT4 total protein and mRNA were normal in the insulin-resistant subjects. Muscle GLUT3 protein and mRNA were lower than controls by 62% and 71%, respectively. GLUT1 mRNA was twice normal, whereas GLUT1 protein content was not significantly increased. GLUT4 protein was markedly redistributed to the muscle plasma membrane in subjects with severe insulin resistance compared with normals (92% v 40% GLUT4 in plasma membrane-enriched fractions, P <.001), whereas the percentage of GLUT1 and GLUT3 protein found in the plasma membrane-enriched fractions was not different from controls. These data document differences in the expression of genes for GLUT1 and GLUT3 in muscle from normal and insulin-resistant subjects. Further, insulin resistance with fasting hyperinsulinemia was associated with a redistribution of GLUT4 to the muscle cell surface with no change in total GLUT4 protein. These data suggest that glucose transporter gene expression and their basal distribution in human muscle are related to insulin resistance and could be determinants of whole body insulin responsiveness.

Acanthosis Nigricans↗
PubMed2000

The effect of pelvic ileal reservoir volume and antiperistaltic reflux on emptying efficiency.

PURPOSE: The emptying efficiency of four different designs of pelvic ileal reservoir was compared using two different techniques of measurement. METHOD: Thirty-four patients were studied one year after restorative proctocolectomy. In each the ileal reservoir was filled with methyl cellulose paste labeled with 51chromium-chromate and technetium Tc 99m-diethylenetriamine pentaacetic acid. Percentage evacuation was calculated from 1) the difference in 51chromium activity between the recovered effluent and the total paste administered and 2) gamma camera measurements of technetium Tc 99m-diethylenetriamine pentaacetic acid activity within the ileal reservoir before and after evacuation. RESULTS: Median evacuation using the 51chromium method was 84, 90, 70, and 75 percent for the W40, W30, J40, and J30 reservoirs respectively. The results were not significantly different from those obtained using the gamma camera: 83, 87, 67, and 71 percent (P = not significant). Patients with either type of W reservoir evacuate isotope-labeled paste more efficiently than patients with J40 reservoirs (P < 0.05 and P < 0.001, respectively) but not J30 reservoirs (P = not significant). However, if the actual volume of paste evacuated during a visit to the lavatory is measured, it is greatest for J40 reservoirs (median, 300 ml compared with 258 ml for W40, 289 ml for W30, and 268 ml for J30; P = not significant). CONCLUSIONS: Gamma camera measurement of ileal reservoir emptying is as accurate as our previous standard technique and provides a qualitative record of pouch evacuation, which may reveal reasons for inefficient emptying. The gamma camera images reveal that the difference in emptying percentage between W and J pouches is because of reflux of paste into the afferent ileum occurring more frequently in J pouches than in W pouches. The effect of this phenomenon on emptying is more than compensated for by the increase in reservoir capacity created by the reflux.

Adolescent↗
PubMed1998

Paradoxical high anal resting pressures in men with idiopathic fecal seepage.

PURPOSE: Fecal incontinence has been a matter of concern for many years, but seepage is poorly understood, especially in men. METHODS: We compared the results of anorectal physiologic tests in a group of 16 male patients who complained of fecal soiling but had no previous history of anorectal surgery or disease and had normal clinical examinations with findings of 16 normal male controls. Physical examination and proctosigmoidoscopy were normal in each patient. RESULTS: Maximum anal resting pressure (median interquartile range) was 136 (120-145) cm H2O in the "seepage" group and 104 (83-112) cm H2O in controls (P < 0.01). Inflation volumes at which patients and controls experienced rectal sensation were 45 (35-80) and 90 (75-100) ml of air, respectively (P < 0.01). Maximum tolerated volumes in the rectum were 130 (85-180) ml of air in the seepage group and 190 (140-240) ml of air in controls (P < 0.01). Median length of the anal sphincter was 3.75 (3.5-4) cm in patients and 3 (3-3.5) cm in controls (P < 0.01). Maximum squeeze pressures, sensation in the anal canal, and sphincter relaxation in response to rectal distention were similar in the two groups. CONCLUSION: Male patients with "idiopathic" fecal seepage have a long anal sphincter with abnormally high resting tone.

Adult↗
PubMed1997

One-stage restorative proctocolectomy without temporary ileostomy for ulcerative colitis: a note of caution.

PURPOSE: This study was designed to determine the safety of omitting a temporary defunctioning ileostomy in restorative proctocolectomy for ulcerative colitis. METHOD: One hundred consecutive patients with ulcerative colitis were treated electively by restorative proctocolectomy and pouch-anal anastomosis, without mucosal stripping; 50 had a defunctioning ileostomy added, and 50 underwent a one-stage procedure without ileostomy. RESULTS: There was no operative mortality. The incidence of postoperative complications was similar in the two groups of patients. Life-threatening complications, however, were more common among patients who did not have a defunctioning ileostomy, of whom 11 developed pelvic sepsis and 7 required reoperation. Among patients with an ileostomy, seven developed pelvic sepsis but none required reoperation (P < 0.02). Emergency reoperations were required in 11 patients without an ileostomy but in only 1 patient with an ileostomy (P < 0.01). CONCLUSION: One-stage restorative proctocolectomy without a defunctioning ileostomy is associated with increased risk to life. Its routine use cannot be recommended.

Adolescent↗
PubMed1996

Does eversion of the anorectum during restorative proctocolectomy influence functional outcome?

PURPOSE: The aim of this study was to determine the effect of eversion of the anorectum during restorative proctocolectomy (RP) for ulcerative colitis on functional outcome. METHODS: One hundred seventeen patients underwent RP with stapled end-to-end ileal pouch-anal anastomosis (EEA), without resection of the anal mucosa. Sixty-four underwent EEA with eversion of the anorectum, and 53 underwent EEA without eversion. Each patient underwent paired studies of anorectal function before and a median of 12 months after RP. RESULTS: One year after RP, median (interquartile range) maximum resting pressure was 69 (range, 51-88) cmH2O in those patients who underwent eversion vs. 80 (range, 64-90) cmH2O in patients without eversion (P < 0.04). Threshold sensation in the upper, middle, and lower thirds of the anal canal were 9.1, 7.4, and 6.8 mA after eversion vs. 6.9, 4.9, and 3.8 mA without eversion (P = 0.003, P < 0.001, P < 0.001, respectively). Before operation, all patients had a rectoanal inhibitory reflex; however, after RP, 54 of 64 patients in the eversion group and 50 of 53 patients with a stapled EEA without eversion had an inhibitory reflex (P = not significant). Leakage of mucus was experienced by 11 patients who underwent eversion, compared with 9 patients without eversion. Fifty-six of 64 patients with eversion could defer defecation for more than 30 min compared with 43 of 53 patients without eversion. Twenty-two of 64 patients in the eversion group retained perfect discrimination between flatus and feces compared with 38 of 54 without eversion (P < 0.001). Level of the anastomosis was 1 (range, 0.5-3) cm above dentate line after eversion compared with 1.5 (range, 0-6) cm without eversion. CONCLUSION: Clinical outcome after RP with eversion was not as good as outcome after stapled EEA without eversion. Such a conclusion requires confirmation in a prospective control trial.

Adult↗
PubMed1996

Prospective controlled trial of duplicated (J) versus quadruplicated (W) pelvic ileal reservoirs in restorative proctocolectomy for ulcerative colitis.

AIMS: A prospective randomised controlled trial was conducted to find out what influence the design of the pelvic reservoir had on the functional outcome. PATIENTS AND METHODS: Sixty patients received either a duplicated (J) or a quadruplicated (W) reservoir, constructed with either 30 or 40 cm of ileum. Each patient underwent laboratory tests of anorectal function before and one year after operation. RESULTS: One year after operation, 57 patients were available for assessment: each had good anal continence, though eight experienced minor leakage of mucus, and all were able to defer defecation for more than 15 minutes. Median bowel frequency in 24 hours (IQR) in patients with J reservoirs (5 (4-7)) did not differ significantly from that of patients with W reservoirs (5 (4-6)). Likewise, bowel frequency in patients with the smaller (30 cm) reservoirs did not differ significantly from bowel frequency in patients with the larger (40 cm) reservoirs. However, patients with large W40 reservoirs had the lowest bowel frequency of the four groups (median 4 per 24 hours, p = NS). The capacity and compliance of the W40 reservoirs were greater than those of the other types of reservoir, but the differences were not statistically significant. CONCLUSIONS: These findings provide support for the use of a relatively small (30 cm), duplicated (J) ileal reservoir, which is simple to construct with linear stapling instruments.

Adolescent↗
PubMed1995

Factors that influence functional outcome after coloanal anastomosis for carcinoma of the rectum.

Thirty consecutive patients had laboratory assessment of anorectal function after rectal excision and stapled coloanal anastomosis for rectal carcinoma. Eleven patients experienced perfect continence but 19 had faecal leakage with or without urgency of defaecation. Median (interquartile range) function was related to the pressures generated in the anal sphincter at rest (good versus poor function: 80 (63-91) versus 51 (23-60) cmH2O, P < 0.01), during maximum squeeze (160 (126-203) versus 102 (58-112) cmH2O, P < 0.01) and during reflex inhibition (58 (23-63) versus 36 (18-54) cmH2O, P < 0.05). Poor function was significantly commoner in women than in men (P < 0.01). These findings suggest that occult damage may have occurred to the anal sphincter before low anterior resection. Careful preoperative evaluation with manometry and endoanal ultrasonography may detect such damage and allow selection of patients for colopouch reconstruction.

Adult↗
PubMed1995

Clinical and physiological evaluation of anorectal eversion during restorative proctocolectomy.

Fifty patients had a restorative proctocolectomy with stapled end-to-end ileoanal anastomosis by the eversion technique. Median (interquartile range) maximum resting anal pressure was 90 (73-116) cmH2O before restorative proctocolectomy and 71 (51-88) cmH2O 1 year after surgery (P < 0.001). Median maximum squeeze pressure was 141 (110-185) cmH2O before surgery and 146 (118-186) cmH2O 1 year after surgery (P not significant). Median thresholds for sensation in the lower third of the anal canal before and 1 year after surgery were 5.3 and 7.1 mA, respectively (P = 0.006). One year after restorative proctocolectomy, all patients were continent, although two experienced leakage of mucus requiring a pad. Forty-two patients (84 per cent) could discriminate between faeces and flatus. Eversion of the anorectum during restorative proctocolectomy impairs the motor and sensory functions of the anal sphincter. Most patients achieved satisfactory anal continence, however, despite these physiological changes.

Adolescent↗
PubMed1995

Potential disadvantages of post-operative adjuvant radiotherapy after anterior resection for rectal cancer: a pilot study of sphincter function, rectal capacity and clinical outcome.

The aim of this study was to try to gauge the functional effect of post-operative adjuvant radiotherapy after potentially curative anterior resection for carcinoma of the rectum. Anorectal function was studied both in the laboratory and clinically in 59 patients, a median of 12 months (range 6-96) after operation. Nine patients received post-operative radiotherapy and 50 matched patients were treated by surgery alone. Though maximum resting anal pressures and maximum squeeze pressures were similar in the two groups of patients, the length and pressure profile of the anal sphincter were both markedly abnormal after radiotherapy. The capacity and compliance of the neorectum were diminished significantly after radiotherapy (maximum tolerated volume 53 ml vs 110 ml after surgery alone, P = 0.008, compliance 1.5 ml/cm H2O vs 3.7 ml/cm H2O after surgery alone, p = 0.018) and the amount of distension of the neorectum required to produced maximum inhibition of the anal sphincter during the rectoanal inhibitory reflex was also significantly diminished after radiotherapy (P = 0.005). Clinical anorectal function was worse among patients who had received radiotherapy, a greater proportion of whom experienced both urgency of defaecation and varying degrees of incontinence. Major faecal leakage necessitating the use of a pad was recorded in 3 of the 59 patients after radiotherapy (one of whom required a permanent colostomy), but in only 5 of 50 patients after surgery alone.

Adult↗
PubMed1995

Recovery of physiologic and clinical function after low anterior resection of the rectum for carcinoma: myth or reality?

PURPOSE: The aim of this study was to examine the serial changes that take place in the first year after low anterior resection for rectal carcinoma, in terms both of anorectal physiology and clinical bowel function. Our hypothesis was that some patients never regain satisfactory anorectal function, because the operative procedure leads to permanent impairment of anorectal reflex and motor function. METHOD: Nineteen patients underwent serial tests of anorectal function, before and for one year after low anterior resection. The median level of the anastomosis above the anal high-pressure zone was 3 (range, 1-6) cm. RESULTS: Anal resting pressure (median (interquartile range)) was significantly decreased three months after operation (62 (46-72) cm H2O) and one year after operation was still significantly less (58 (48-73) cm H2O) than before operation (77 (58-93) cm H2O) (P < 0.01). Maximum tolerated volume in the neorectum decreased from 130 (88-193) ml before operation to 80 (51-89) ml three months after operation (P < 0.005) but returned to preoperative values by six months (125 (60-140) ml) (P = not significant) and remained at these values one year after operation. The volume in the "neorectal" balloon required to elicit a maximum rectoanal inhibitory reflex was significantly less three months after operation than before operation (50 (43-60) ml compared with 100 (73-100) ml; P < 0.005); one year after operation, the volume required was still significantly less than before operation (50 ml vs. 100 ml) (P < 0.015). Bowel frequency increased from 1 (1-2) in 24 hours before operation to 4 (2-5) times in 24 hours after operation and remained at 4 times in 24 hours throughout the first year after operation. Three months after operation, 53 percent of patients experienced some degree of fecal leakage and 24 percent experienced urgency of defecation. These aspects of bowel function improved with time, but even one year after operation, 29 percent of patients continued to experience fecal leakage and 18 percent wore a protective pad. CONCLUSIONS: Anal resting pressure decreased significantly after low anterior resection and did not recover in the course of the first year after operation. Moreover, the volume of an air-filled balloon in the neorectum that was required to elicit maximum inhibition of the anal sphincter was significantly less after anterior resection that before operation. These long-term and presumably permanent changes in physiologic behavior of the anoneorectum after low anterior resection provide an explanation for the failure of some patients to regain satisfactory bowel function following that procedure.

Aged↗
PubMed1995

Why do some patients experience poor functional results after anterior resection of the rectum for carcinoma?

PURPOSE: The aim of this study was to examine the dynamic inter-relationship of the anal sphincter, residual rectum, and neorectum after low anterior resection for rectal carcinoma. METHODS: Seventy-three patients underwent laboratory tests of anorectal function a median of ten (range 1-100) months after operation. All patients completed quality of life questionnaires and had the level of their anastomoses determined by rigid sigmoidoscopy. Forty-four patients (60 percent) had some form of disturbance of bowel function, which was classified as "poor" function if bowel frequency was four or more in 24 hours and if there was also either fecal leakage or urgency of defecation. Manometric data were analyzed using stepwise logistic regression analysis. RESULTS: Only two factors were found to be significantly and independently associated with poor bowel function, namely, the pressure recorded in the upper part of the anal sphincter in response to distention of the neorectum (15 (7-24) cm of water in patients with poor function vs. 29 (15-58) cm in patients with good function; P < 0.005) and the level of the anastomosis above the anal sphincteric high pressure zone (2.5 (2-3.5) cm in patients with poor function vs. 6 (4-12) cm in patients with good function; P < 0.005). CONCLUSION: Continence after anterior resection is related to an appropriate "sampling" response in the anal sphincter to activity within the neorectum. This in turn, is directly related to length of the residual rectum, which is, therefore, of crucial importance to function.

Aged↗
PubMed1995

Preservation of complete anal sphincteric proprioception in restorative proctocolectomy: the inhibitory reflex and fine control of continence need not be impaired.

This study evaluates whether reflux function of the anal sphincter remains unchanged after restorative proctocolectomy, provided that the sphincter remaining is kept intact, without mucosal stripping or endo-anal anastomosis. Paired tests of anorectal function were performed before, and a median of 6 (range 2-12) months after restorative proctocolectomy with stapled, end to end pouch-anal anastomosis. Beforehand, distension of the rectum with 50 ml of air produced a median (interquartile range) increase in pressure within the rectum of 22 (15-29) cm H2O and reflex inhibition of the anal sphincter from a pressure of 76 (62-106) cm H2O to a pressure of 34 (15-52) cm H2O. After the procedure, distension of the ileal pouch with 50 ml of air produced an increase in pressure within the pouch of only 5 (4-8) cm H2O (p < 0.001 compared with beforehand) and reflex inhibition of the anal sphincter from a pressure of 62 (25-79) cm H2O to 37 (17-68) cm H2O. Maximal reflex inhibition of the upper third if the anal sphincter to a pressure of 26 (15-48) cm H2O was observed when pressure within the pouch increased by 16 (11-22) cm H2O. After restorative proctocolectomy, all patients were continent (two experienced minor nocturnal leakage of mucus) and 25 could discriminate between flatus and faeces. Thus, reflux function was preserved in response to changes in pressure, ensuring that the subtler aspects of anal continence were preserved.

Adolescent↗
PubMed1995

The perfect pelvic pouch--what makes the difference?

The aim of this study was to determine what factors are important for the achievement of perfect anal continence after restorative proctocolectomy. One hundred patients underwent paired studies of anorectal physiology before and one year after restorative proctocolectomy with pelvic ileal reservoir (11 S, 25 J, 64 W) with stapled ileoanal anastomosis, without mucosectomy. Fifty seven patients attained perfect anal continence and were able to discriminate flatus from faeces with such confidence that they were able to release flatus safely without fear of faecal soiling. The remaining 43 patients experienced minor problems in this regard. Four factors were found to correlate significantly with a perfect functional result (median, perfect v imperfect): maximum resting anal pressure (72 v 57 cm H2O, p < 0.02), the sensory threshold in the upper and mid-anal canal (7.3 v 8.6 and 5.3 v 7.0 mA, p < 0.05 and p < 0.02), compliance of the ileal reservoir (12.4 v 7.6 ml/cm H2O, p < 0.01), and the presence of a pouch-anal inhibitory reflex (56 of 57 patients v 29 of 43 patients, p < 0.01). The quality of anal continence depends on several factors: a complaint ileal reservoir, a strong sensitive anal sphincter, and normal reflex coordination of the activities of the reservoir and the sphincter. Excellent pouch-anal coordination is obtainable irrespective of the design of the reservoir, provided that these criteria are satisfied.

Adolescent↗
PubMed1994

Decrease in the anorectal pressure gradient after low anterior resection of the rectum. A study using continuous ambulatory manometry.

PURPOSE: Changes in anorectal function after low anterior resection of the rectum (LAR) often lead to symptoms of urgency and frequency of defecation, the anterior resection syndrome. It has been reported that preservation of part of the rectum improves clinical results, but why this should be remains unclear. METHODS: We have carried out continuous ambulatory manometric studies in two groups of patients: 11 patients, a median of 11 (range, 5-96) months after LAR, in whom the median anastomotic level above the anal high-pressure zone was 0 (range, 0-2) cm; 9 patients, a median of 6 (range, 3-12) months after sigmoid colectomy, in whom the rectum remained in situ and who acted as controls. RESULTS: Comparing the LAR group with controls, resting anal pressures were lower, median 68 (range 27-102) cm H2O vs. 95 (45-116) cm H2O (P < 0.05), and neorectal pressures were higher, 25 (0-48) cm H2O vs. 10 (0-10) cm H2O (P < 0.01). Thus the anorectal pressure gradients were less, 34 (0-74) cm H2O vs. 81 (35-113) cm H2O (P < 0.01). Slow-wave activity in the anal sphincter was present in six patients (55 percent) after coloanal anastomosis and eight patients (89 percent) after sigmoid colectomy. Sampling episodes were seen in only two patients (18 percent) after coloanal anastomosis and five patients (56 percent) after sigmoid colectomy. When clinical endpoints were compared (LAR vs. controls), bowel frequency in 24 hours was higher, 5 (3-8) vs. 2 (1-3) (P < 0.01); fecal leakage was more common, affecting seven patients (64 percent) vs. one patient (11 percent) (P < 0.05), and urgency of defecation was also more common. CONCLUSIONS: The inferior clinical results observed after LAR compared with the results after sigmoid colectomy are thus in part because of higher neorectal pressure acting on a weakened sphincter mechanism. These observations lend support to the idea that neorectal capacity should be increased in patients who undergo low anterior resection.

Aged↗
PubMed1994

Bowel diversion should be used with caution in stenosing anal Crohn's disease.

Proximal diversion has commonly been used for severe perianal Crohn's disease in an attempt to relieve local symptoms, whether the primary intestinal disease is in the colon or small bowel. Two patients are presented in whom diversion led to severe symptomatic disease in the previously normal defunctioned bowel. In each case the development of colonic disease was associated with increasing anal stenosis leading to retention of purulent fluid within the bowel lumen. Faecal stream diversion should be used with caution in stenosing anal Crohn's disease.

Abscess↗
PubMed1994

Audit of patients' experiences of cholecystectomy: laparoscopic and open operations compared.

A study was undertaken to compare open cholecystectomy with laparoscopic in terms of patient related variables. This was not a randomized study but compared two groups of patients treated at different times. A number of variables were assessed. The study showed that each method was equally effective in treating symptomatic gall stone disease. Very few significant differences, in terms of the patients' perceptions of the procedures, were found, although the trend appeared to favour the laparoscopic procedure.

Adult↗