Biomedical subjects
A M Roe
Publications and source records attributed to A M Roe.
Slow transit constipation. Comparison between patients with or without previous hysterectomy.
We have studied 31 patients with slow transit constipation. Fourteen developed severe symptoms following a hysterectomy, while the remainder had symptoms arising de novo and unrelated to pelvic surgery. To establish whether there were specific abnormalities which might be linked to hysterectomy, we compared the two groups. Rectosigmoid motility was impaired in the de novo group. Functional sphincter length, maximum resting anal canal pressure, and the rectoanal inhibitory reflex were not significantly different from controls. The majority of patients were able to significantly increase the anorectal angle on straining to defecate. Patients in the de novo group had a higher sensory threshold for rectal filling compared with controls, whereas the posthysterectomy group was not significantly different. Electromyography of the external sphincter showed failure of appropriate inhibition of resting activity in 57% of the de novo and 38% of posthysterectomy patients. The de novo group had hypoactivity of the rectosigmoid and an insensitive rectum. The abnormality in the hysterectomy group is less clear and any precise link between slow transit constipation and hysterectomy remains obscure.
An analysis of rectal morphology in obstructed defaecation.
Obstructed defaecation in the descending perineum syndrome has been attributed to anterior mucosal prolapse. Manometric and radiological measurements together with evacuation proctograms in 49 patients with obstructed defaecation and normal whole gut transit times were carried out and compared in a total of 25 controls. Proctography delineated four groups: (I) puborectalis accentuation, n = 11; (II) rectal intussusception, n = 25; (III) anterior rectal wall prolapse, n = 11; (IV) rectocele, n = 2. The anorectal angle at rest, maximum basal sphincter pressures and the rectoanal inhibitory reflex did not differ between the groups and controls. Group III achieved a greater increase in anorectal angle on straining than controls. Groups II and III exhibited significant perineal descent below the pubococcygeal line whereas group I did not. In perineal descent intussusception was the commonest morphological abnormality associated with obstructed defaecation. Isolated anterior mucosal prolapse was not observed, making local treatment aimed at reducing its bulk questionable.
Submucosal versus ligation excision haemorrhoidectomy: a comparison of anal sensation, anal sphincter manometry and postoperative pain and function.
Submucosal (SM) and ligation excision (LE) haemorrhoidectomy were compared to establish whether SM is a less painful procedure and whether anal sensation is better preserved by SM, and, if so, how this relates to postoperative function. There were 18 SM and 22 LE patients. Anal sphincter manometry and anal mucosal electrosensitivity were measured pre-operatively and 6 weeks after surgery. Postoperative pain was assessed by linear analogue scale. Anal sphincter pressures which were high pre-operatively fell to normal after surgery. Neither operation affected functional sphincter length or the recto-anal inhibitory reflex. Forty per cent of patients showed ultraslow waves on sphincter motility studies. These were associated with the highest pressures and in all but three cases disappeared after surgery. There were no differences in postoperative pain scores between the two techniques but there was a wide range from no pain to very severe pain in both groups. Submucosal haemorrhoidectomy preserved anal sensation better than ligation excision but this was not reflected in improved function. There was minor leakage and soiling in 50 per cent of patients from both groups and two SM and LE patients had initial faecal incontinence. All these symptoms had resolved by 6 weeks.
Preoperative staging of local invasion in rectal cancer using endoluminal ultrasound.
Digital examination is the most commonly used method of assessing local invasion in rectal cancer, but it is highly subjective and accuracy is related to surgical experience. The use of transrectal ultrasound in the preoperative staging of rectal cancer has been assessed in 51 patients with histologically proven rectal cancers. Results showed a high degree of correlation when compared with postoperative histopathology (r = 0.91, P less than 0.001). Invasion beyond the muscularis propria was predicted with a sensitivity of 97%, specificity of 92% and predictive value of 97%.
An evaluation of a direct access flexible fibreoptic sigmoidoscopy service.
During a 3 year period 146 general practitioners referred 630 patients to a direct access flexible sigmoidoscopy clinic. The yield was 53.3% with significant colonic or rectal pathology in 30%. Twenty six cancers, 4 Dukes' A, and 38 patients with symptomatic adenomatous polyps were detected. Five further cancers were detected by subsequent barium enemas. The service reduced delay in diagnosing colorectal pathology but did not reduce the number of barium enemas requested by general practitioners. It is suggested that where facilities are already available, such a service to investigate rectal bleeding in patients over 40 years is of benefit both to patients and general practitioners.
New method for assessment of anal sensation in various anorectal disorders.
A new technique for quantifying anal sensation utilizing mucosal electrosensitivity is described and has been tested in 97 patients. Normal subjects (n = 20) have a sensory threshold varying from 2 to 7.3 mA being most acute in the region of the anal valves. Sensory awareness also extends into the upper anal canal. Patients with neuropathic incontinence (n = 17) have a sensory deficit (P less than 0.002) whilst patients with haemorrhoids (n = 28) have less sensitive mucosa displaced into the upper anal canal (P less than 0.0001). Patients with acute fissure-in-ano (n = 10) have lower thresholds of sensation at the site of the fissure and slow transit constipation patients (n = 22) have normal anal sensation. The technique is reproducible and should prove useful in the investigation of anorectal disorders.
Endoluminal ultrasound in the assessment of local invasion in rectal cancer.
A new method for staging local invasion in rectal cancer has been assessed. Thirty-eight patients with primary rectal cancers have been examined pre-operatively with endoluminal rectal ultrasound and results compared with histological analysis of resected specimens in 33 cases. Three patients who also underwent laparotomy but not resection had good evidence of both stage T3 (1) and T4 (2) disease. The coefficient of correlation between ultrasonic and histological staging was 0.93 (P less than 0.001). Invasion beyond the muscularis propria was predicted with a sensitivity of 96 per cent, specificity of 92 per cent and a predictive value of 96 per cent.
Diagnosis and surgical management of intractable constipation.
Seventy-four patients with intractable constipation, of whom thirty-three had slow and forty-one normal intestinal transit, were investigated to determine the aetiology of their disorder and plan treatment. Patients with slow transit had a greater incidence of abdominal pain and distension (P less than 0.001) and only 9 per cent had a normal call to stool compared with 71 per cent of those with normal transit (P less than 0.001). Internal and sphincter function as assessed by sphincter pressures, length and the recto-anal inhibitory reflex did not reveal any difference between the groups and normal controls; similarly anal sensation and rectal compliance were normal. However, those with normal transit had a higher threshold of rectal sensation than controls (P less than 0.05). Slow transit patients failed to show a postprandial increase in rectosigmoid motility compared with controls (P less than 0.05). Whilst the majority failed to inhibit the external sphincter on bearing down, half of those with normal transit produced either partial or complete inhibition. Both groups were able to increase the anorectal angle on straining. Twenty-two normal transit patients had abnormal perineal descent compared with controls (P less than 0.0005). Patients with perineal descent exhibited abnormal rectal morphology. Rectal intussusception was observed in 13 of 35 evacuation proctograms. On the basis of the data presented, we could not justify internal sphincterotomy of puborectalis division. Our policy in severe slow transit constipation was to offer colectomy and ileorectal anastomosis. In five out of seven to date, a successful result has been achieved. Eight patients with rectal intussusception have undergone an abdominal rectopexy with significant improvement in three. In our hands, the evacuation proctogram and transit studies were the most useful preoperative investigations.
Flap-valve theory of anorectal continence.
The most important component of continence is considered to be the puborectalis muscle which is reputed to function by creating a flap-valve mechanism in which the anterior rectal wall occludes the upper and canal. To elucidate this, anal and rectal pressures were measured simultaneously together with external anal sphincter and puborectalis electromyogram and synchronously superimposed on an image intensifier displaying the rectum outlined by barium. We studied 13 subjects at rest, and during a Valsalva manoeuvre. There was a significant rise in rectal and sphincter pressures (P less than 0.005) and external sphincter and puborectalis EMG (P less than 0.005). In a further 13 patients Valsalva manoeuvres were performed during proctography alone. In all subjects the anterior rectal wall was always clearly separated from the upper sphincter despite a maximal effort and a rectum filled with sufficient liquid to produce a desire to defaecate. These findings question the flap-valve theory of continence and suggest the puborectalis functions by sphincteric occlusion of the anal canal.
The relationship between perineal descent and denervation of the puborectalis in continent patients.
It has been suggested that perineal descent causes puborectalis neuropathy. To elucidate this, perineal descent was measured on standard proctograms and prolongation of mean motor unit potential duration was used as the index of denervation of the external sphincter and puborectalis in 9 male and 18 female patients with perineal descent and obstructed defaecation. The findings were compared with 21 normal controls. There was no significant perineal descent below the pubococcygeal line at rest but both males and females had abnormal descent of the anorectal angle on straining and a similar degree of external sphincter neuropathy. Females, however, exhibited a significant degree of puborectalis denervation compared with controls (p less than 0.001) and with male patients (p less than 0.001). Thus external sphincter denervation was associated with perineal descent in both sexes whereas other causes, of which obstetric trauma is a possibility, must be implicated in the puborectalis neuropathy of the females studied.
Techniques in evacuation proctography in the diagnosis of intractable constipation and related disorders.
A technique of evacuation proctography using a simple barium and air mixture is described. The study can be easily combined with a barium enema examination. A series of 35 patients with intractable constipation have been studied and compared with 7 controls. Most of the abnormalities seen using more elaborate methods of defaecography were identified. Variants of rectal intussusception were found in 16 patients. Other diagnoses included rectocele, mucosal and full rectal prolapse, accentuation of puborectalis impression and solitary rectal ulcer. The technique should prove useful in the management of patients with disorders of defaecation.
What is the best way of measuring perineal descent? A comparison of radiographic and clinical methods.
The 'perineometer' underestimated movement of the pelvic floor by nearly 60 per cent in 21 patients tested; mean descent was 1.2 cm, compared with a radiographic mean descent of 2.9 cm (P less than 0.001). Since the instrument measures movement of the anal verge, not the pelvic floor, no account is taken of anal canal shortening. Radiographic methods are still necessary for the reliable identification of abnormal descent.
Evacuation proctography in obstructed defaecation and rectal intussusception.
The symptoms of obstructed defaecation may present as a number of different syndromes including descending perineum, solitary rectal ulcer, irritable bowel and mucosal or complete rectal prolapse. In order to clarify the pathophysiology of obstructed defaecation we carried out dynamic and static radiological investigations together with manometric and electrophysiological measurements in ten patients with severe, intractable obstructed defaecation. Results were compared with a total of 35 control subjects. There were no significant differences in sphincter pressures or the recto-anal inhibitory reflex between patients and controls. Mean motor unit potential duration was prolonged in patients compared with controls (P less than 0.02) in the puborectalis and external sphincter indicative of neuropathic changes. X-ray measurements of the anorectal angle and perineal descent at rest showed no differences. However, obstructed defaecation patients had a greater increase in anorectal angle on straining (P less than 0.02) and significantly more descent on straining (P less than 0.002). Fast film sequence evacuation proctography showed that the anal canal was occluded by anterior rectal wall in four patients and five patients had variants of recto-rectal intussusception without overt rectal prolapse, which explained the obstructive symptoms. This information should allow the surgeon to follow a rational treatment programme based on the anatomical abnormality.
Metal binding by pharmaceuticals. Part 4. A comparative investigation of the interaction of metal ions with hydralazine, prizidilol and related compounds.
The metal complexing properties of two antihypertensive drugs, hydralazine (1-hydrazinophthalazine) and prizidilol (a hydrazinopyridazine), and some related ligands, have been studied using potentiometry, elemental analysis, spectrophotometry and computer simulation. The coordination chemistry of 1-hydrazinophthalazine and the hydrazinopyridazines is similar in that Ca(II), Mg(II), and Mn(II) complexes are not formed, whereas Zn(II), Cu(II) and Fe(II)/Fe(III) complexes are produced. Both kinds of ligand react with Fe(II) to form a brightly coloured tetrazene complex which is insoluble for hydralazine but soluble for prizidilol. Computer simulation studies indicate that the most prevalent metal complex of prizidilol in blood plasma is [Fe2+(Priz-)H+]2+ but that this only forms at very high drug concentrations. It is concluded that prizidilol is unlikely to have any direct effects on the metabolism or distribution of the trace elements listed here.
Colonoscopy preparation with Picolax.
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Potential histamine H2-receptor antagonists. 4. Benzylhistamines.
As part of our studies aimed at designing histamine H2-receptor antagonists, the effect on histaminergic activity of introducing benzyl substituents at various positions in the histamine molecule is described. New synthetic methods are reported for the novel 4-benzyl-, beta-benzyl- and 4,N tau-dibenylhistamines and the reported 2-benzylhistamine. The novel N tau-benzylhistamine was synthesized by the versatile route reported by us for the synthesis of N tau-methylhistamine. These benzylhistamines, together with the reported N alpha- and N pi-benzylhistamines, were tested for agonist and antagonist activity at both H1 and H2 receptors. The results obtained indicate that introduction of a benzyl group into the histamine molecule causes a marked reduction in H1- or H2-agonist activity, and none of the compounds showed consistent antagonist activity. Evidently, the sterically demanding benzyl substituent is not easily accommodated in the agonist binding mode and is unable to locate a lipophilic receptor region for potential hydrophobic binding.
Neck injury caused by ski stick.
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