Biomedical subjects

S Laurberg

Publications and source records attributed to S Laurberg.

At least 91 records · Page 5Linked to original sources

PubMed1994

Diverting colostomy induces mucosal and muscular atrophy in rat distal colon.

The progress of adaptive changes in the left colon after diverting colostomy was studied in rats using stereological techniques. Standardised segments of left colon proximal and distal to the colostomy was examined after 0, 1, 2, 4, or 12 weeks. In excluded colon the mucosal weight was reduced by 37% (p < 0.01) and the luminal surface area by 47% (p < 0.01) after four weeks and reached a steady state at this point of time, as no further reduction was seen from 4 to 12 weeks. The number of proliferating crypt cells was determined immunohistochemically after in vivo labelling with bromodeoxyuridine and was compared with the total number of colonocytes. Total bowel rest leads to a reduction in the number of proliferating epithelial cells and not to a reduced average life span. The weight of the muscularis propria decreased by 32% after four weeks (p < 0.01) and by 48% after 12 weeks (p < 0.001), whereas the weight of the submucosa was unchanged. No adaptive changes were found in segments proximal to the colostomy. These results show that the wall composition of defunctioned colon in rats is radically changed resulting from a mucosal and muscular atrophy, and from a reduction in luminal surface area.

Animals↗

PubMed1994

Growth hormone treatment of rats with chronic diverting colostomy. Differential response on proximal functioning and distal atrophic colon.

Diversion of colon from the fecal stream leads to profound intestinal atrophy. After diverting colostomy for 4 weeks, female rats were treated with biosynthetic human growth hormone (b-hGH; 2.0 mg.kg-1 body wt.day-1) in order to investigate whether b-hGH could reverse atrophic changes in distal colon, with special reference to changes in morphometric composition, collagen content and biomechanical properties. Biosynthetic hGH treatment for 28 days stimulated growth of the muscularis propria of the defunctioned, atrophic colon (p < 0.05), whereas the mucosal atrophy was unaffected by the treatment. In colon proximal to the colostomy, however, b-hGH increased the colonic wet weight (p < 0.01), defatted dry weight (p < 0.005) and the collagen content (p < 0.05). Morphometric analysis showed that the growth increase was localized to the mucosa and the muscularis propria. In conclusion, fecal diversion alters the response of b-hGH treatment and indicates that the trophic effect of growth hormone on colonic mucosa is dependent on fecal bulk passage, whereas the trophic effect on muscularis propria is fully retained when colon is deprived of luminal nutrients.

Animals↗

PubMed1993

Decrease in collagenous proteins and mechanical strength of distal colon after diverting colostomy in rats.

The effects of a diverting colostomy on weight, collagen content, and biomechanical strength of the left colon was investigated in rats. Female rats received either a diverting colostomy or a sham-operation and were killed randomly 1, 2, 4, or 12 weeks after surgery. The dry weight and hydroxyproline content of excluded colon decreased by 37% (P < 0.001, confidence limits (CL) = 21-53%) and 25% (P < 0.001, CL = 18-31%), respectively, after 4 weeks, and by 52% (P < 0.001, CL = 38-66%) and 40% (P < 0.001, CL = 27-53%), respectively, after 12 weeks compared to sham-operated rats. The breaking strength of the defunctioned colon decreased by 21% (P < 0.05, CL = 2-40%) after 4 weeks and by 25% after 12 weeks (P < 0.05, CL = 4-46%). The tensile strength of defunctioned colon (load per unit collagen) was reduced by 19% after 4 weeks (P < 0.05, CL = 6-32%). Proximal to the colostomy site we found no differences in the hydroxyproline content or biomechanical strength. In conclusion, defunctioning of the left colon in rats leads to deterioration in the biomechanical properties caused by a lesser content and a decreased quality in the collagen of the left colon.

Animals↗

PubMed1993

Effect of growth hormone on the inflammatory activity of experimental colitis in rats.

The effect of daily treatment with 2.0 mg biosynthetic human growth hormone per kilogram body weight or isotonic NaCl (controls) on experimental colitis was investigated in rats. Colonic inflammation was induced by instillation of trinitrobenzene sulfonic acid (TNB) intraluminally into the left colon. Untreated NaCl-instilled rats were used for comparison with intact colon. Four days after TNB instillation the growth hormone-treated rats had lower macroscopic and microscopic damage scores and less infiltration of neutrophils, measured as myeloperoxidase activity (MPO), than controls. The biomechanical properties of the colon showed that the breaking strength and energy absorption were reduced in the control rats with colitis compared with intact colon, whereas the rats treated with growth hormone had unchanged strength and energy absorption. The differences in MPO activity, damage scores, and biomechanical properties were associated with a higher concentration of insulin-like growth factor I in serum from growth hormone-treated rats after 4 days than controls. Finally, the growth hormone-treated rats regained their initial body weight after 7 days, in contrast to the body weight of control rats, which remained 11% lower than their initial body weight.

Animals↗

PubMed1992

Risks of anal incontinence from subsequent vaginal delivery after a complete obstetric anal sphincter tear.

OBJECTIVE: To assess the influence of various risk factors on long term anal incontinence in women with a complete obstetric tear of the anal sphincter. DESIGN: Postal questionnaire. SETTING: Department of Gynecology and Obstetrics, Aarhus University Hospital, Denmark. SUBJECTS: 152 women with complete obstetric tear of the anal sphincter. MAIN OUTCOME MEASURES: Occurrence and duration of anal incontinence in relation to any delivery. RESULTS: 56 of 121 respondents had experienced a subsequent vaginal delivery; 23 (41%) of these had had transient anorectal incontinence directly after the complete tear and four (7%) had permanent anorectal incontinence. In the 23 women with transient anorectal incontinence directly after the complete tear, 9 (39%; 95% CI 19%-59%) developed anorectal incontinence after the next delivery, and this was permanent in four (17.4%; 95% CI 2%-33%). In the 29 women without anorectal incontinence after complete tear, two had transient incontinence of flatus but for less than 14 days after the next delivery. CONCLUSIONS: Transient anal incontinence after a complete tear is a predictor of anal incontinence after subsequent vaginal delivery. The major long term problem in our study of premenopausal women was incontinence of flatus. This possibility should be discussed with the women when a further pregnancy is planned.

Adult↗

PubMed1992

Intervention during labor: risk factors associated with complete tear of the anal sphincter.

Among 41,200 consecutive deliveries there were 152 cases of complete tear of the anal sphincter (complete tear). In a case-control design, the association between interventions during labor (forceps, vacuum extraction, use of oxytocin and prostaglandins and mediolateral episiotomy) and complete tear, were evaluated by confounder control using multiple logistic regression analysis. Controls chosen were the patients delivering just before and after the index patient with complete tear. Use of Kielland forceps, mediolateral episiotomy, shoulder dystocia and nulliparity were significantly associated with complete tear. Maternal age, presentation in labor, duration of second stage of labor and the indication for instrumental deliveries and episiotomy had no significant association with complete tear.

Adult↗

PubMed1991

Postoperative biosynthetic human growth hormone increases the strength and collagen deposition of experimental colonic anastomoses.

This study examined the effects of preoperative treatment with 2.0 mg biosynthetic human growth hormone (b-hGH)/kg/day on the bursting strength and collagen deposition of experimental left colonic anastomoses, and of intact colon from sham-operated rats. The anastomotic bursting pressure was 55% higher in the b-hGH treated animals on day 2 (p less than 0.05) and 79% higher on day 4 (NS; p = 0.056), and the bursting wall tension was 65% higher on day 2 (p less than 0.05) and 112% higher on day 4 postoperatively (p less than 0.05), than saline-injected controls. The hydroxyproline content of the anastomotic segment in the b-hGH treated rats increased by 56% on day 4 (p less than 0.005) and by 30% on day 6 postoperatively (p less than 0.05), compared with controls. At 3 cm proximal to the anastomoses the defatted dry weight and hydroxyproline content of the healing colons were increased after 6 days compared with the sham-operated rats. There was, however, no difference between the b-hGH treated rats and the paired controls, indicating that growth hormone is not involved in this process.

Anastomosis, Surgical↗

PubMed1991

Influence of bilateral oophorectomy and estrogen substitution on the striated anal sphincter in adult female rats.

A quantitative histologic analysis of the striated anal sphincter of 24-month-old virgin female rats was performed to evaluate the effect of oophorectomy and estrogen substitution. The oophorectomized rats had a 21% (11-31%, 95% confidence limits) reduction in the cross-sectional area of the striated muscle tissue compared with controls. This was due to a reduction in the mean cross-sectional area of the muscle fiber, whereas the number of fibers was unchanged. Although the relative amount of stromal tissue was increased in the oophorectomized rats, the total stromal tissue was unchanged. No difference in the cross-sectional area of muscle tissue was found between the estrogen-substituted, oophorectomized rats and controls. This indicates that the estrogen depletion in the oophorectomized rats has induced the reduction in muscle tissue in the striated anal sphincter.

Anal Canal↗

PubMed1991

Age-related changes in the striated anal sphincter in female rats. A quantitative morphometric study.

A quantitative histologic analysis of the striated anal sphincter of virgin female rats aged 2 months and 24 months was performed to evaluate age-related changes. A 27% (8% to 46%, 95% confidence limits) increase in the cross-sectional area of the muscle in the older rats was observed compared with the young. This was due to an increase in both muscle and connective tissue. There was hypertrophy of both the small and large muscle fibres without change in the number with age. No evidence of age-related degenerative changes in this muscle in the virgin female rat was found.

Aging↗

PubMed1990

Effect of postanal repair on progress of neurogenic damage to the pelvic floor.

Physiological evaluation of the anorectum and pelvic floor muscles was carried out in 18 patients before and 9-35 months after postanal repair for anorectal incontinence. Thirteen patients (72 per cent) were improved, but in these patients the fibre density in the external anal sphincter muscle and the pudendal nerve terminal motor latency were both increased after surgery. In the five patients not improved after surgery only a few unstable motor unit potentials could be recorded in the external anal sphincter muscle. In two of these patients the pudendal nerve terminal motor latency could not be recorded after surgery. We suggest that this progression in the neurogenic damage to the pelvic floor muscles after postanal repair may be caused by the operation, and that it may be responsible for the poor functional outcome noted in some patients.

Action Potentials↗

PubMed1990

Long-term observation of the detrusor smooth muscle in rats. Its relationship to ovariectomy and estrogen treatment.

We studied the bladders of 24-month-old intact rats, rats that had been ovariectomized at the age of 6 months, and intact and ovariectomized rats treated by estrogen from the age of 16 months. The study thus comprized four groups: group I: bilaterally ovariectomized rats; group II: intact rats; group III: ovariectomized rats treated with estrogen; group IV: intact rats treated with estrogen. The weight and collagen concentration of the bladders were determined. The ovariectomized bladders weighed significantly less and had a higher collagen concentration than the intact bladders. Estrogen substitution for ovariectomized rats reversed these parameters. Detrusor strips were also used for organ bath studies. All bladders were similar in regard to the nerve-mediated frequency-response relationship. The atropine-resistant response was studied by adding scopolamine to the organ bath. Strips from ovariectomized rats had a significantly diminished atropine-resistant response, which was abolished by estrogen substitution. The present study suggests that micturition problems in menopause might have a structural as well as a pharmacological explanation.

Animals↗

PubMed1990

Growth hormone increases the bursting strength of colonic anastomoses. An experimental study in the rat.

The effect of growth hormone on the bursting strength of left colonic anastomoses was investigated experimentally. Seventy-two 3 month-old female rats were randomized into two groups receiving daily injection of either saline (controls) or 2.0 mg biosynthetic human growth hormone per kg body weight per day. All injections were started 7 days before a left colonic resection and anastomosis, and continued until sacrifice at the 2nd, 4th or 6th post-operative day. The bursting strength of the anastomoses was tested in anaesthetized, living rats. The bursting pressure and the bursting wall tension of the growth hormone treated animals were increased two-fold on the second post-operative day (2p less than 0.005) and three-fold on the fourth post-operative day (2p less than 0.05), compared with controls. There was no difference in the bursting pressure or the bursting wall tension on the sixth postoperative day. The mass of the resected segment was increased by the pre-operative growth hormone treatment, whereas the hydroxyproline content was unchanged. In conclusion, treatment with biosynthetic human growth hormone increases the strength of colonic anastomoses in the early phases of healing.

Anastomosis, Surgical↗

PubMed1990

Growth hormone increases the mass, the collagenous proteins, and the strength of rat colon.

The effect of growth hormone treatment on the left colon was investigated in 4-month-old Wistar rats. The animals were injected with saline (controls) or biosynthetic human growth hormone (b-hGH) in doses of 1.0 and 5.0 mg b-hGH/kg/day for 30 days. The total body weight of the rats injected with 1.0 mg b-hGH/kg/day did not differ from that of the control group, whereas the body weight of the rats injected with 5.0 mg b-hGH/kg/day was increased by 37% compared with the control group. The colonic dry weight per unit length was increased by 57% and 46% by 1.0 mg and 5.0 mg b-hGH/kg/day, respectively. The defatted dry weight was increased by 52% and 44%, respectively. The hydroxyproline content per unit length was increased by 31% and 23%, respectively. Furthermore, the biomechanical strength was increased by the b-hGH injections. No difference between the two b-hGH doses was found in any of the data.

Animals↗

PubMed1989

Anorectal physiology validated: a repeatability study of the motor and sensory tests of anorectal function.

Sixteen subjects (mean (s.d.) age 50.7 (12.8) years, three men) were studied on two separate occasions by two experienced investigators in random order. A standard protocol of anatomical, manometric and electrophysiological assessments of anorectal motor and sensory function was followed. No significant differences were found between the results obtained by the two investigators in the measurements of perineal descent, anal canal length, and canal resting pressure and squeeze pressure, pudendal nerve terminal motor latency, single-fibre electromyography fibre density of the external anal sphincter, and thresholds of mucosal electrosensitivity. This study shows that the standard tests of anorectal sensorimotor function are repeatable by different investigators. In addition, it suggests that comparison of data obtained in different centres using these techniques is valid.

Adult↗

PubMed1989

Effects of aging on the anorectal sphincters and their innervation.

The effects of aging on the pelvic floor musculature and its innervation are described in 102 women and 19 men without colorectal or pelvic floor disease. In the women, a reduction in anorectal "squeeze" pressure was found in the fifth decade, but the resting anal pressure remained unchanged. This reduction in squeeze anal pressure was accompanied by an increase in the mean pudendal nerve terminal motor latency, indicating damage to this nerve, and increased perineal descent in the resting and straining positions. The fiber density, recorded by single fiber electromyography in the external anal sphincter muscle, a muscle innervated by the pudendal nerves, was increased in the sixth decade, indicating the later development of compensatory reinnervation in this muscle. The interrelation of aging, menopausal effects, and parity in these changes is difficult to define from currently available data, but the authors suggest, from other evidence, that menopausal effects may be relevant.

Adult↗

PubMed1989

Endoscopic sclerotherapy of oesophageal varices in rabbits. The long-term effect on oesophageal collagen content and mechanical strength.

Sixteen rabbits with oesophageal varices were randomized to no treatment (n = 8) or endoscopic paravenous sclerotherapy of the varices (n = 8). Eight other rabbits served as sham-operated controls. Four months after sclerotherapy the animals were killed, and the mechanical strength and collagen content of the oesophagus were determined at proximal, middle, and distal levels. In animals treated by sclerotherapy there was a 15% increase in collagen content at the distal level when compared with controls and non-treated animals (2p less than 0.05). This was not accompanied by changes in the mechanical strength. At middle and proximal levels there were no differences between the groups. It is concluded that the late effect of one single session of paravenous sclerotherapy of oesophageal varices is a slight fibrosis in the distal oesophagus, with no changes in the mechanical properties of the oesophageal wall.

Animals↗

PubMed1988

Neurologic cause of idiopathic incontinence.

The relationship between the pudendal and perineal nerve terminal motor latencies and descent (weakness) of the perineum on straining was investigated in 31 patients with idiopathic fecal incontinence, and in 30 patients with double incontinence. Pelvic floor descent was correlated with increased pudendal nerve terminal motor latency in both groups of patients. In the patients with double incontinence, there was a less significant correlation between perineal descent and increased perineal nerve terminal motor latency. In the patients with fecal incontinence, but without urinary incontinence, there was no correlation between perineal descent and perineal nerve terminal motor latency. These data support the concept that pelvic floor weakness can result in damage to the pudendal and perineal nerves, leading to fecal and urinary incontinence. In patients with isolated fecal incontinence the perineal nerves are relatively spared. Thus these common types of incontinence probably have a neurologic cause, and neurophysiologic methods can be used in their assessment.

Adult↗

PubMed1988

Delayed external sphincter repair for obstetric tear.

In some patients with faecal incontinence due to an obstetric tear of the external and sphincter there is additional weakness of the anal sphincter muscles from damage to the innervation of these muscles during delivery. Of 19 patients who required surgical repair of an obstetric sphincter tear some months or years after injury, 9 (47 per cent) had evidence of pudendal nerve damage at pre-operative anorectal physiological investigation. The result of surgical repair was excellent or good in eight of the ten patients in whom there was no evidence of nerve damage, while this was the case in only one of the nine patients with nerve damage. These results are significantly different (P = 0.018). Thus the functional result of delayed anal sphincter repair after obstetric lesions is partly dependent upon whether the nerve supply is intact. Pre-operative physiological evaluation can give information on the probability of a successful surgical result.

Adult↗