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Objective: To compare healing of one-layer colonic anastomoses with or without a soluble intraluminal prosthesis (* SBS-tube)., Design: Randomised, partly blinded controlled study., Setting: University hospital, Denmark., Subjects: 16 female Danish country strain pigs, of which 8 had the SBS tube inserted and 8 acted as controls., Interventions: One-layer colonic anastomoses either hand-sewn (n = 8, controls) or hand-sewn onto an SBS tube (n = 8)., Main Outcome Measures: Macroscopic evaluation, leakage test, breaking strength, histology, oxygen tension in and near the anastomosis peroperatively and 4 days postoperatively., Results: Three quarters of the tubes (n = 8) dissolved in less than 2 hours. Histological examination showed significantly better structured layers and more mucosal epithelial covering in the SBS group. The other histological variables examined were: tissue gap (p < 0.08), inflammation (p < 0.10), breaking strength (p < 0.46) and amount of granulation tissue (p < 0.71), but the last findings were not significant. Oxygen tension at the anastomotic line was better in the SBS tube group, but not significantly so., Conclusions: We conclude that the SBS tube facilitates the sewing of the anastomosis and may improve healing, possibly because of better apposition of the cut ends and reduced tension in the sutures.

The influence of advanced age on the mechanical strength of colonic anastomoses and skin incisional wounds in diabetic rats was investigated after 0 (suture binding capacity) and after 7 days of healing. Furthermore, the effects of growth hormone (GH) injections to old diabetic rats were investigated. Diabetes in old rats did not influence the strength of colonic anastomoses after 0 and 7 days. However, in these diabetic animals, the strength of skin incisional wounds was reduced by 27% after 7 days of healing (P< 0.01). GH injections administered to old diabetic rats doubled the mortality compared with that of saline-injected old diabetic rats (P< 0.01). GH injections did not influence the strength formation of either colonic anastomoses or skin incisional wounds in old normal rats. In conclusion, the healing of colonic anastomoses in diabetic rats was not compromised by old age, while the strength of skin wounds was decreased., (Copyright 1999 Harcourt Publishers Ltd.)

The influence of growth hormone (GH; 2 mg/kg/day) administration on the mechanical breaking strength of colonic anastomoses in diabetic rats has been investigated on the day of operation (suture binding capacity) and after 4 and 7 days of healing. In diabetic rats, the suture binding capacity was decreased by 26% in both ultimate load and relative failure energy. After 4 days of healing, no difference was observed between control and diabetic animals. After 7 days, relative failure energy in the diabetic animals was reduced by 33%. GH administration to diabetic animals did not alter strength during the first week of healing. We found an increased circumference (33%) and defatted dry weight (22%) of the colon in diabetic rats. In conclusion, diabetes impairs the suture-binding capacity of the colon in rats, while there is only little influence on healing in the following week. GH administration could not influence the strength of colonic anastomoses in diabetic animals.

The mechanical strength development of healing wounds depends on the formation of collagen fibrils bridging the wound cleft. A considerable deposition, degradation, and remodeling of these fibrils takes place influencing the mechanical strength of the healing wounds. A method for studies of wound collagen metabolism in vivo is delineated, enabling determination of collagen deposition per hour in rat colon anastomoses and skin incisional wounds. Labeled proline was incorporated into wound collagen with a flooding dose of unlabeled proline, reducing errors introduced by proline recycling and proline de novo synthesis. The mechanical strength was determined by a materials testing machine. In both colon anastomoses and skin wounds a substantial increase in collagen deposition was observed at Day 2, reached a maximum at Day 6, and was still relatively high at Day 12 during the remodeling of collagen fibers in the wound cleft. The collagen deposition in colon anastomoses at Day 6, however, was 10-fold higher compared with that of the skin incisional wounds. The time course of the collagen deposition was much alike in colon anastomoses and skin incisional wounds reaching a maximum at Day 6. The mechanical strength of these two rather different types of wounds was increased correspondingly and to the same level during the 1st week of healing. The measurements of collagen deposition, collagen content, and biomechanical strength indicated a substantial turnover of newly synthesized and deposited collagen during the early phases of wound healing. On the basis of this, it seems obvious that even small disturbances to the balance between collagen synthesis, deposition, collagen cross-linking, and collagen degradation/remodeling may result in defective wound healing.

Purpose: This experimental study was designed to investigate the collagen fibrils of colonic anastomoses in rats and to compare normal healing with rats treated with biosynthetic growth hormone (bGH)., Methods: The healing zone of left colonic anastomoses was studied at days 2, 4, and 6 after surgery by means of scanning electron microscopy., Results: After four days of healing a normal anastomosis was filled with loosely packed and unorganized collagen fibrils, which were organized into collagen fibers after six days. Compared with normal anastomoses, rats treated with bGH showed a more organized healing, characterized by a dense structure of a new-formed collagen framework of fibrils and immature collagen fibers after six days., Conclusions: Healing colonic anastomoses are characterized by new-formed collagen fibrils at postoperative day 4, and bGH seems to stimulate structural organization of the anastomotic collagen fibrils into fibers.

Background: The purpose was to investigate how growth hormone exerts its stimulating effect on the healing of experimental colonic anastomoses., Methods: Rats were treated with biosynthetic growth hormone (bGH); the anastomotic breaking strength, collagen content, and collagen deposition rate (labeling of collagen with 14C-proline) were compared to saline treated controls., Results: bGH increased the breaking strength when the rats were treated before and after the operation and when bGH treatment was started at operation and continued during the healing period. No effect on these parameters was seen, however, when treatment was given only before operation. The collagen deposition rate of the intact colon was accelerated from 0.6% to 1.0% per hour at operation after 7 days of preoperative treatment. The anastomotic collagen deposition rate was increased on day 4 from 4.4% in the controls to 9.0% in the anastomosed rats given bGH from operation and to 12.9% in rats given bGH from 7 days before operation until day 4 after operation, resulting in a higher anastomotic collagen content., Conclusions: Treatment of rats with bGH in the healing phase increases the breaking strength of colonic anastomoses caused by a stimulation of the collagen deposition rate of the anastomotic segment.

The biomechanical properties and intestinal wall composition of left colon were studied in 4-month-old, 14-month-old, and 27-month-old male rats. The hydroxyproline content and hydroxyproline concentration in old rats were increased by 36% and 26%, respectively, compared with young rats and by 20% and 17%, respectively, compared with middle-aged rats. In middle-aged rats the maximum load increased by 21%, compared with young rats. In old rats, however, the maximum load decreased by 13%, compared with middle-aged rats. Histological examination showed that the mean crypt height was 9% higher in middle-aged rats and 12% higher in old rats than in young rats. In conclusion, an accumulation of collagenous proteins was found in old rats compared with middle-aged rats and this was accompanied by a decrease in the strength, which may deteriorate the functional integrity of the left colonic wall with age.

The effects of treatment with 2.7 mg biosynthetic human growth hormone (b-hGH; 2.7 mg/kg b.w./day) for 80 days on the biomechanical properties and collagen deposition of the left colon were studied in 27-month-old male rats. The b-hGH-treated rats increased in body weight by 17%, and the wet weight of colon by 31%. The defatted dry weight and the hydroxyproline content of the left colon were increased by 41 and 29%, respectively, compared with controls. The biomechanical analysis showed that the maximum load and stiffness of the left colonic specimens in the b-hGH-treated group were enhanced by 27 and 60%, respectively, and the strain at maximum load was 24% less than in the control group. The maximum 'stress' and stiffness were 40 and 73% higher, respectively, than in the controls. Histological examination demonstrated that the mean crypt heights was 9% higher in the b-hGH-treated rats than in the controls. Consequently, treatment of old rats with b-hGH may increase the strength, collagen deposition and mucosal crypt height of the left colon.

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.

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.

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.