Biomedical subjects
Publications and source records attributed to F Penninckx.
We determined the maximum closing capability of the internal anal sphincter muscle ring in vitro and in vivo. The internal sphincter, 4 to 6 mm thick, cannot close the anal canal hermetically, not even during maximal contraction. The blood-filled anal cushions have to fill up an intrasphincteric gap of at least 7 to 8 mm in diameter.
Widespread alterations of the gut autonomic nervous system have been described in Crohn's disease. Immunohistochemistry shows that these alterations are associated with the expression of major histocompatibility (MHC) class II antigens (HLA-DR) on enteroglial cells in the ganglia of the submucous and myenteric plexuses and on the enteroglial sheaths of the nerve extensions. Neuronal cell bodies and extensions do not express MHC class II antigens. The class II expression is associated with the presence of UCHL1-positive T lymphocytes. MHC class II expression can also be found on endothelial cells and vascular smooth muscle cells but not on smooth muscle cells of the muscularis mucosae or propria. The intensity of MHC class II expression on the glial cells of the enteric nervous plexus and on endothelial cells correlates well with the intensity of class II expression on epithelial cells.
The human IAS has particular structural and functional characteristics. This smooth muscle constantly generates rhythmic electrical slow waves, but no action potentials. The slow waves are linked to calcium fluxes and both are essential for mechanical activity, i.e. the ASPW. The IAS is pharmacologically characterized by the presence of alpha excitatory and beta inhibitory adrenergic receptors. Cholinergic drugs have an indirect effect through the release of an inhibitory neurotransmitter, very probably VIP, from NANC nerves. The myogenic activity of the IAS is enhanced by its extrinsic sympathetic innervation. Thus, at rest, the IAS is in a state of partial tetanus and contributes approximately 55% of the MABP. Because the IAS ring cannot be completely closed, the anal mucosa and the haemorrhoidal plexuses fill the gap. By compressing these tissues, the IAS perfectly closes the anal canal to retain not only solids but also fluid stool and gas. Acute rectal distension and rectal activity, mainly through intramural pathways, induce reflex IAS relaxation, permitting the rectal contents to be sampled by receptors in the upper anal canal while continence is temporarily maintained by EAS activity and by expansion of the haemorrhoidal cushions. There is a correlation between the volume of rectal distension and the parameters of IAS relaxation. At maximal IAS relaxation, ASPW are absent, indicating the completeness of the inhibition. Although this RAIR is not essential for defecation, insufficient relaxation may be implicated in constipation. Hyperactivity of the IAS resulting in a high MABP and AUSPW has been considered both as a cause and as an effect in haemorrhoids and anal fissure. Continence for fluids and gas is impaired if IAS activity is decreased (i.e. a low MABP), either by direct trauma or by damage of its sympathetic innervation. Severe faecal incontinence will develop when the contractility of both the IAS and the EAS is affected.
We tested the efficacy of rifabutin and ethambutol in combination in healing severe recurrent Crohn's disease in the neoterminal ileum. Sixteen patients who had undergone an ileal resection with partial colectomy and ileocolonic anastomosis and who had severe recurrent lesions in the neoterminal ileum at baseline ileocolonoscopy were included in the study. The patients received rifabutin in a dose of 5 mg/kg together with ethambutol, 20 mg/kg. Ten patients were treated for 6 months; six patients dropped out because of adverse events. As no effect was observed after 6 months, five patients completed a 12-month therapy course. Follow-up ileocolonoscopy was performed at 3, 6, and 12 months. In none of the 10 patients who completed the 6-month trial and in none of the five patients who completed 12 months of therapy was endoscopic improvement of the lesions observed. In four patients the disease was clinically progressive, and two patients underwent a reresection after 6 and 8 months, respectively. This study shows that long-term therapy with rifabutin and ethambutol does not heal Crohn's disease in the neoterminal ileum and does not prevent recurrence of symptoms and complications.
Aphthous lesions recur in the neoterminal ileum within the first few months after curative resection of the distal ileum in patients with Crohn's disease. These lesions do not originate from microscopic disease that is already present at the time of surgery. To investigate the importance of faecal stream in the pathogenesis of recurrent Crohn's lesions, we have studied 5 patients with Crohn's disease who had ileal resection. After curative resection and ileocolonic anastomosis, a diverting terminal ileostomy was constructed 25-35 cm proximal to the anastomosis thereby excluding the neoterminal ileum, the anastomosis, and the colon from intestinal transit. After six months of exclusion, endoscopy of the ileocolon was undertaken and biopsy specimens were taken. Transit was then restored. Six months after reanastomosis further biopsy specimens were taken. These patients were compared with a control group of 75 patients with Crohn's disease who underwent a one-step ileal resection and ileocolonic anastomosis. None of the 5 patients had endoscopic lesions in the neoterminal ileum after six months of exclusion and biopsies did not show inflammatory changes characteristic of Crohn's disease. By contrast, 53 of 75 patients with one-step surgery had endoscopic recurrence in the neoterminal ileum within six months of surgery. All 5 patients had an important recurrence of disease, both endoscopically and histologically, at ileocolonoscopy six months after reanastomosis. Our findings strongly support the view that recurrence of Crohn's disease in the neoterminal ileum after curative ileal resection is dependent on faecal stream.
Anismus, paradoxical external sphincter function, spastic pelvic floor syndrome, rectoanal dysnergia, abdomino-levator incoordination for abdominopelvic asychronism, are all due to paradoxical contraction of the striated sphincter apparatus during voiding and is characterised by prolonged and excessive straining at stool. Biofeedback is the treatment of choice and has to be introduced at an early stage. We present the results of an ambulatory approach based on the integration of simulated balloon defaecation with small (50 ml) as well as constant rectal sensation volume, defaecometry and anal manometry. The pathophysiology visualised by the patient's own anorectal pressure recordings on the screen of a personal computer is explained and corrected. Sixteen patients were treated and followed for at least 1 year. Manometric data were normal except for an increased minimum residual pressure and rectal compliance. Nine patients could not evacuate a 50 ml bolus initially. Simulated defaecation became possible in seven out of these nine patients when the bolus was increased up to the individual constant rectal sensation volume. Two patients could not evacuate this volume either, while defaecation was made much less laborious in the other seven patients. Paradoxical contraction was immediately corrected in 7/16 cases. Also, as an immediate, objective benefit of a single training session, improved defaecation of a 50 ml bolus was observed in 11 patients. This effect was preserved after 6 weeks in nine cases; symptomatic recurrence did not occur in these patients during follow-up. This method of defaecation training has many advantages as compared with sphincter training using EMG electrodes eventually performed in the absence of a desire to defaecate or in lying position.(ABSTRACT TRUNCATED AT 250 WORDS)
Seven experts drew the rectal axes of 18 representative proctographic images on two occasions, with a 1-year interval, in order to assess intraobserver variation in the determination of the anorectal angle (ARA). Intraobserver variation (6%) and interobserver variation (17%) were smallest when the central rectal axis was used to determine the ARA. A strong relation was found between inter- and intraobserver variation (r = 0.77). Intraobserver variation tended to be rather small for pictures made during straining, but a relation with the magnitude of the ARA was not found. Although none of the seven experts could reproduce the rectal axes with less than or equal to 10% variation in all 18 pictures, redrawing of the central rectal axis delivered less than or equal to 10% variation in 86% of determinations. It is concluded that intraobserver variation is influenced by the expertise of the investigator, the method of analysis, and the anorectal configuration to be analyzed. Radiologic assessment of the ARA may yield reliable data on the dynamics of the anorectum if performed by a single investigator on x-ray films that allow confident analysis.
Cellular swelling of erythrocytes exposed to Me2SO during freezing and thawing may lead to hemolysis upon dilution of the cryoprotectant with pure electrolyte buffer. Excessive cell swelling is effectively avoided by exposing the RBC to the nonpenetrating sorbitol after thawing and before dilution. Due to the initial reduction in volume by sorbitol, cell swelling upon dilution may not cause hemolysis particularly with concentrations of 0.05 to 0.15 M of sorbitol in the diluting electrolyte buffer. Membrane damage incurred during freezing and thawing is particularly pronounced with the older red cell population, while the younger population membrane integrity can be preserved to an optimal degree.
Twelve selected patients undergoing cholecystectomy were operated in a prospective randomised study by laparoscopy (CO2 laser) or by classic surgery. Our preliminary results suggest that laparoscopic cholecystectomy is of clinical benefit as compared to classic cholecystectomy since it reduces the surgical trauma, limiting weight loss and shortening the hospital stay.
A method is presented for the identification and analysis of constipation due to difficult evacuation of rectal content. This condition--which has not been elucidated by former techniques--was identified in 5 out of the 19 constipated patients by this new method. Disturbed defecation was characterized by prolonged evacuation of the simulated stool and the greater work performed during this process. The cause of this phenomenon was the paradox movement of the pelvic floor, i.e. contraction instead of relaxation. The results' highlight: the excessive straining can induce a neuromuscular damage to the pelvic floor. The clinical importance of this method lies in the clarification of the principle, that the therapy of this condition must be initiated as early as possible.
Determination of the anorectal angle (ARA) and the position of the pelvic floor is, theoretically, very important in understanding the mechanisms of anorectal continence and defaecation. The variability in the measurement of the ARA was analyzed. Nine experts drew ther rectal axis either as a line along the posterior wall of the distal rectum or as the central axis of the rectal lumen on the outlines of 18 representative proctographic images. The standard deviations and ranges of the mean values of each ARA were comparable but large in both methods. On average, the S.D. was 8 degrees and the range value about 23 degrees. Inter-observer variation was not related to the magnitude of the ARA, but rather to the anorectal configuration. Drawing a line along the posterior distal rectal wall is difficult when it is irregular or when the puborectalis impression is indistinct. The central rectal axis is difficult to draw when the junction between the upper and lower rectum is ill defined or when the outlines of the distal rectum are asymmetric e.g. by the presence of a rectocele. Thus, the variability of both methods was not strongly interrelated (r = 0.68 for the median values). It is concluded that, in general, radiologic assessment of the ARA is not reliable enough for comparative investigation of the dynamics of the anorectum.
Two cases of endometriosis of the cecal area are reported. In one case, the endometriosis was located in the appendix causing intussusception into the cecum. Both cases were associated with localizations of endometriosis in the rectosigmoid.
The alterations of several small-intestinal mucosal enzymes have been examined in cats that underwent different periods (1-4 hr) of occlusion of the superior mesenteric artery, followed by 4 hr of reperfusion. The damage progressed during ischemia and reperfusion from the villus tips to the crypts: first, there was a rapid decrease in the activity of maltase, a brush-border enzyme; a slower decline occurred in two cytoplasmic enzymes, aldolase A (with preferential location in feline villus cells) and lactate dehydrogenase (with an ubiquitous distribution); a lag preceded the decrease in aldolase B (a cytoplasmic enzyme shown to occur mainly in feline crypt cells). For all these enzymes, the initial period of reperfusion was associated with a greater decrease in enzyme activity than persisting ischemia. By determination of the unsedimentable proportion of glutamate dehydrogenase (a mitochondrial matrix enzyme) and of acid phosphatase (a lysosomal enzyme) it was demonstrated that ischemia caused important mitochondrial damage before the cells were lost, whereas no lysosomal damage was observed in any condition. These sensitive parameters of cell damage can serve as a criterion for an adequate evaluation of potential cytoprotective agents.
The role of the distal stomach in gastric emptying was studied. Ten patients with proximal gastric vagotomy (PV) and 10 age-matched patients with Roux-en-Y gastro-jejunostomy (R-Y) were compared with 10 healthy controls. Gastric emptying of solids and liquids was determined by the use of Tc-99m SC scrambled eggs and In-111 DTPA. In PV, gastric emptying of both solids and liquids was delayed; the prolongation with solids was mainly accounted for by an abnormal lag phase. In R-Y patients, no lag phase was observed, and the solid emptying curve pattern was characterized by early rapid emptying followed by very slow emptying. Both the solid and liquid phases were prolonged. The lag phase is affected by proximal vagotomy and is mainly determined by the distal stomach, which appears to be essential for normal emptying.
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The maximal anal basal pressure (MABP) was measured with probes of 0.3, 1, 2 and 3 cm diameter in 21 subjects, 60 years old, without anal pathology. The components of MABP were analyzed by inducing a maximal internal sphincter (IS) relaxation, taking pressure measurements in the conscious state and during narcosis with curarization. In seven cases pressure measurements were done on isolated anorectum after abdominoperineal rectum amputation. MABP increases with probe diameter before as well as during anaesthesia with curarization. The contribution of the striated sphincter tonic activity is constant within the range of probe diameters used. At rest, i.e. when the 0.3 cm diameter pressure recording probe is used, 30% of MABP is made up by striated sphincter tonic activity, 45% of it is due to nerve induced IS activity, 10% to purely myogenic IS activity and 15% can be attributed to the expansion of the haemorrhoidal plexuses. Although MABP is mainly based on active forces generated by the smooth and striated sphincter apparatus, the presence of the anal cushions is essential for perfect anal continence, as they have to fill the gap within the IS ring to hermetically close the anal canal. The global IS activity, contributing 50-60% of MABP at rest, can completely be inhibited by a maximal rectoanal inhibitory reflex. Stretching of passive elements starts at 1 cm anal distension, but steeply increases thereafter, accounting for 65% of the MABP at 3 cm anal distension. It is deduced that optimal stool diameter is about 2 cm.
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