Differential Effects of Surgical Suture Materials in 1,2-Dimethylhydrazine- Induced Rat Intestinal Neoplasia1

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[CANCER RESEARCH 44, 2827-2830, July 1984]

Differential Effects of Surgical Suture Materials in 1,2-Dimethylhydrazine- induced Rat Intestinal Neoplasia1

Ronald N. Calderisi and Hugh J. Freeman2

Department of Medicine (Gastroenterology). University oÃBritish Columbia Faculty of Medicine and Cancer Research Center, Vancouver, British Columbia V6T 1W5 Canada

ABSTRACT bowel tumors. The cecum was selected for suture placement, since this is a relatively resistant site to tumor development in The incidence, distribution, size, and histopathology of rat this animal model. The results indicate that specific types of small and large bowel tumors induced by sequential administra suture materials promote tumor induction locally in the rat cecum, tion of 1,2-dimethylhydrazine followed by cecal placement of one while stainless steel significantly increased tumors at a distal of six differing types of suture materials were systematically colonie site "downstream" from the cecum. examined. In addition, measurements of /3-glucuronidase activi ties in large bowel contents followed by fecal trace metal deter minations were done. The results indicate that specific slowly MATERIALS AND METHODS absorbed and nonabsorbable suture materials in the absence of Animals and Diets. Weaned male Wistar rats (Simonsen Laboratories, a surgical anastomosis promote tumor induction locally in the rat Inc., Gilroy, CA) weighing 140 to 160 g were administered water ad cecum. In addition, cecal suture material composed of multifila- libitum at all times and standard laboratory chow pellets (Ralston Purina ment stainless steel wire enhanced tumor development at a Co., St. Louis, MO). Rats were randomly assigned to one of 7 groups "downstream" site in the distal colon, paralleling increased fecal using suspended wire mesh cages to reduce coprophagia. Relative /3-glucuronidase activities at this site and implicating a possible humidity and environmental air temperature were constant, and a 12-hr luminally mediated mechanism for colon tumor development in light-dark cycle was imposed in a carcinogen containment animal facility. Carcinogenesis. All rats were weighed weekly and received 1,2- this animal model. dimethylhydrazinedihydrochloride (Aldrich Chemical Co., Milwaukee, Wl) administered as 12 weekly s.c. 25-mg/kg injections. This was prepared INTRODUCTION as a 0.5% solution in 1 mM EDTA (Mallinckrodt, Inc., St. Louis, MO) adjusted to pH 6.5 with sodium bicarbonate. Previous studies had The use of carcinogen-induced animal models to examine established this as an effective regimen in our laboratory for small and factors that may influence the pathogenesis of gastrointestinal large bowel tumor induction (8,9,18). neoplasia is well recognized (1). The effects of various dietary Surgical Procedures. All animals were anesthetized with an i.p. factors, such as dietary fiber (4, 8, 9), as well as the influence of injection of pentobarbital (50 mg/kg body weight) and underwent lapa- various surgical procedures (17,18,26,27) have been examined. rotomy 6 weeks after the last carcinogen injection using the methods of In the past, the concept that chronic mucosal injury may promote Lambert (11). In 6 of the 7 animal groups, a single 3-0 suture was tumor development in the gastrointestinal tract has emerged inserted from serosa through mucosa to serosa, and a triplicate tie was securely applied with care to avoid tissue contraction or injury. All sutures largely from clinical observation. Increased colon cancer rates are reported in long-standing ulcerative colitis (6), foreign bodies were placed within 1 cm of the cecal tip on the antimesenteric aspect approximating the site of the appendix in humans. Suture groups in (23), fistulae (20), inflamed diverticulae (2), and long-standing cluded: surgical gut (absorbable; Ethicon Chromic; Ethicon Sutures, Ltd., tubercular (3) and amebic (5) lesions and observed to complicate Peterborough, Ontario, Canada); polyglycolic acid (absorbable, braided, ureterosigmoidostomy (13, 22). In recent years, a high incidence synthetic; Dexon "S"; American Cyanamid Co., Pearl River, NY); Poly- of tumors localized to anastomotic suture lines has been reported glactin 910 (absorbable, braided, synthetic; Ethicon Vicryl; Ethicon Su following small bowel or colon surgery in animals administered tures, Ltd.); surgical silk (nonabsorbable; Ethicon Silk; Ethicon Sutures, chemical carcinogens (17, 18, 26, 27). Possible mechanisms Ltd.); polypropylene (nonabsorbable, monofilament; Ethicon Prolene, suggested to explain these observations have included mucosal Ethicon Sutures, Ltd.); and stainless steel (nonabsorbable, multifilament hyperplasia frequently observed in animal intestine near anasto wire; Flexon; American Cyanamid Co.). Table 1 summarizes composition and properties of the different suture types. The abdominal wall was moses (17, 26) and chronic irritation induced by nonabsorbable then closed in all groups in 2 layers with 3-0 Dermalene monofilament foreign bodies (14, 17). However, no systematic study, to our polyethylene suture (American Cyanamid Co.). knowledge, has addressed the specific role, if any, of differing Necropsy Studies. Four weeks following surgery, animals were ad suture materials per se in experimental intestinal neoplasia. ministered an overdose of i.p. pentobarbital, and autopsies were carefully In this paper, the effects of 6 different classes of suture performed. The distribution, size, and incidence of small and large bowel materials were examined in rats initially treated with 1,2-di- tumors were recorded. Each tumor detected was oriented separately on monofilament mesh, placed in separate vials containing modified Bouin's methylhydrazine, an agent that induces both small and large fixative (750 ml aqueous saturated picric acid-250 ml 38% formaldehyde- 10 ml glacial acetic acid), embedded in paraffin, sectioned, and stained 1Supported by the National Cancer Institute of Canada and the Canadian with hematoxylin and eosin. Foundation for lleitis and Colitis. Fecal Enzymes. Fecal samples from cecum and distal colon in each 2 Recipient of Research Grant MA 6918 from the Medical Research Council of group of rats were individually collected at the time of the autopsy and Canada. To whom requests for reprints should be addressed, at Gastroenterology, processed as described by Reddy ef al. (15). ÃŸ-Glucuronidase activity ACU F-137, U. B. C. Health Sciences Center Hospital, 2211 Wesbrook Mall. Vancouver, British Columbia, Canada. was quantitated colorimetrically at 550 nm with a Bausch and Lornb Received April 26, 1983; accepted April 2, 1984. Model 710 spectrophotometer (Bausch and Lomb, Inc., Rochester, NY)

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Table 1 SuÃurematerialsand properties Suture" Type Source Properties Surgical gut Chromic Collagenfrom animalintestine Absorption rapid; minimaltissue re treated with chromic salt solu- action tion

PolyglycolicacidPolyglactin910Surgical homopolymerof gly- absorbed; minimaltissue re cohcacidSynthetic actionPolyglycolic

copolymer of lactide acid more rapidly ab andglycolideRaw 910Verysorbed than Polyglactin

silkPolypropyleneStainless silk, a natural protein fiber slowly absorbed; moderate tis silkwormPolymerspun by the suereactionNonabsorbable:

ofpropyteneLow minimaltissue reac tionNonabsorbable;

steelBraidedBraidedBraidedMonofilamentMultielementSyntheticcarbon-iron alloySlowly minimaltissue reac tion " All 3-0 size sutures; see text. 6 See Ref. 19.

Table 2 Tumorfrequency in small and large bowel tumorsGroup8Control All bowel tumorsNo.bowel tumorsNo.bowel of of of of tumors/ of tumors/ ofanimals10(100)tumors/ animals10(100)"animal7.2Â±1.6Canimals9 animal1.7 animal5.5 (90) Â±0.5 Â±1.3 Surgicalgut 10(100) 5.6 Â±0.7 8 (80) 1.7 + 0.4 9 (90) 3.9 Â±0.8 Polyglycolicacid 10(100) 6.6 Â±1.5 8 (80) 1.3 Â±0.3 9 (90) 5.3 Â±1.4 Polyglactin910 10(100) 6.4 Â±0.7 10(100) 2.3 Â±0.4 10(100) 4.1 Â±0.4 Surgical silk 10(100) 6.4 Â±0.6 8 (80) 1.6 Â±0.4 10(100) 4.8 Â±0.5 Polypropylene 10(100) 8.7 Â±1.5 8 (80) 2.0 Â±0.6 9 (90) 6.7 Â±1.1 11.8 Â±1.5"Small Stainless steelNo. 10(100)No. 10(100)No. 2.4 Â±0.5Large10(100)No. 9.4 Â±1.4" 8Ten/group for control and suture groups. " Numbers in parentheses,percentage of animals with tumors. c Mean Â±S.E. " p < 0.05 (f test versus control group; see text). using phenolphthalein mono-0-glucuronic acid (Sigma Chemical Co., St. small bowel, and 407 (77%), in large bowel. Tumors were sessile Louis, MO) as the substrate (7). Protein concentrations were determined plaques or polypoid lesions and ranged in size from 1 to 22 mm by the method of Lowry ef al. (12). in greatest diameter. These findings are similar to those reported Fecal Trace Metals. Following these studies, a separate group of (8,9,18) for 1,2-dimethylhydrazine-treated rats. Although relative weaned male Wistar rats was used to determine fecal trace metals. After proportions of small intestinal tumors are greater in this experi 12 weeks of feeding, anesthesia and laparotomy were performed in 3 mental model compared to the proportions reported at small and groups of rats: controls without cecal suture and 2 cecal suture groups (surgical gut and stainless steel). Four weeks later, fresh stool samples large intestinal sites in humans, their distribution, relative size, were collected, weighed, ashed, weighed dry, and analyzed by atomic and histopathology are similar to those of human intestinal emission spectroscopy for trace metals (Chemex Laboratories, Ltd., epithelial neoplasia (1). North Vancouver, British Columbia, Canada). Tumor Frequency. Table 2 shows the percentage of animals Statistical Analysis. At the conclusion of the study, data were ana in each group with small and large bowel tumors. For all groups lyzed using the Student r test. in this study, all animals had intestinal tumors, and over 80% of animals had tumors detected in either small or large bowel sites RESULTS alone. Among these 7 groups, no statistical differences in per centages of animals with tumors were observed. Animal Weights. For the 7 animal groups, mean body weights Table 2 also shows mean number of small and large bowel of each group were virtually identical for the duration of the tumors detected per rat in each group. Compared with controls, study. During carcinogen administration, no statistical difference both mean total intestinal tumors and mean total large bowel in mean body weight or weekly weight gain among the 7 groups tumors were significantly increased in the stainless steel group was observed. After completion of the carcinogen protocol until compared to the control group (both, p < 0.05). Moreover, the sacrifice, no statistical differences were seen. stainless steel group had significantly more intestinal tumors Necropsy Studies. At sacrifice, suture materials from the than each of the other suture groups (surgical gut, p < 0.005; surgical silk, polypropylene, and stainless steel animal groups polyglycolic acid, p < 0.025; polyglactin, p < 0.005; silk, p < were still present. In the 70 animal autopsies, 527 tumors were 0.005) except for the polypropylene group which failed to achieve detected macroscopically and confirmed as epithelial neoplasia statistical significance. In the small bowel, there were no statis on histological examination. Of these, 120 (23%) were found in tical differences among the 7 animal groups. In the large bowel,

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Table3 Large bowel subsite frequency and distribution coton"No. colonNo. no. of oftumors/ of Of colonie of of of of Group8Control tumors/ of of tumors/ tumors55 animals2 tumors2(4)animal0.2Â±0.1d'eanimals6(60)tumors17(31)animal1.7 animals9 tumors36(65)animal3.6 (20)c Â±0.5 (90) Â±0.9 Surgicalgut 39 0 (0) 0 0 4(40) 8(21) 0.8 Â±0.4 8 (80) 31 (79) 3.1 Â±0.7 Polyglycolicacid 53 5(50) 10(19) 1.0 Â±0.5 5(50) 6(11) 0.6 Â±0.2 0.9 Â±0.3a 8 (80) 37 (70) 3.7 Â±0.9 Polyglactin910 41 6(60) 9(22) 7(70) 13(32) 1.3 Â±0.4 0.8 Â±0.3d 9 (90) 19 (46) 1.9 Â±0.4 Surgicalsilk 48 5(50) 8(17) 6(60) 14(29) 1.4 Â±0.5 9 (90) 26(54) 2.6 Â±0.4 Polypropylene 67 4(40) 7(10) 0.7 Â±0.3 8(80) 18(27) 1.8 Â±0.5 0.8 Â±0.2"Proximal 9 (90) 42 (63) 4.2 Â±0.6 Stainless steelTotal 94CecumNo.6(60)No. 8 (9)No. 9(90)No. 20(21)No. 2.0 Â±0.5No. 10(100)Distal66(70)No. 6.6 Â±1.1" a Ten/group for control and suture groups. Excludes cecum. c Numbers in parentheses, percentage of animals with tumors. "p < 0.05 (( test versus control group; see text). a Mean Â±S.E. the stainless steel group had significantly more tumors than the Table4 0-Glucuronidaseactivities in cecum and distal colon other suture groups (surgical gut, p < 0.005; polyglycolic acid, p Group*Control < 0.05; polyglactin, p < 0.005; silk, p < 0.01) except for poly coton"48.62 propylene which failed to achieve statistical significance. Poly Â±11.68e Â±13.01 52.46+ 9.40 propylene, although not statistically different from the control Surgical gut 54.08+ 8.86 Polyglycolicacid 49.72 Â±12.21 49.68+ 9.47 group, was significantly greater than the surgical gut (p < 0.05) Polyglactin910 49.68 Â± 8.26 57.96 Â±10.36 and polyglactin (p < 0.05) suture groups. Surgical silk 42.48 Â±13.47 49.84+ 7.86 Polypropylene 50.06+ 12.22 51.42Â±14.12 Subsite Distribution. Table 3 shows the distribution and fre Stainless steelCecum"44.3248.84 Â±12.48Distal 94.46 Â± 8.64" quency of tumors in the large bowel. Except for the surgical gut Six/group. group where no cecal tumors were observed, at least 50% of Phenolphthaleinliberated (jig/hr) at 56Â°(7); protein determined according to the method of Lowry ef al. (12). the animals in each of the other 5 suture groups had cecal c Mean Â±S.E. tumors. This compared to a 20% frequency in the control group. p < 0.05 (f test versus control group; see text). The mean number of cecal tumors was greater in each of these suture groups compared to controls, and statistical significance Tables was achieved with polyglactin, silk, and stainless steel wire (all Fecal iron and chromium levels determined by atomic emissionspectroscopy ot p < 0.05). In the proximal colon, the percentage of animals in ashed rat stool (ppm/g, each group with tumors at this site was comparable with no Group"Control (%/g, dry wt.feces)0.15 dry wt,feces)19.5 statistical differences in mean number of tumors detected be Â±0.026 tween control and 6 suture groups. However, significantly in Â±11.6 Surgical gut 0.14 Â±0.01 16.2 Â± 2.9 creased numbers of proximal colon tumors were observed in the 5.6aStainlesssteelIron 0.16 Â±0.02Chromium 21.6 Â± polypropylene and stainless steel groups compared to the poly Six/group. " Mean Â±S.E. glycolic acid group (p < 0.05 and p < 0.02, respectively). In the distal colon, comparable numbers of animals in each group had tumors at this site. However, the mean number of for fecal iron and chromium determinations. No statistical differ colon tumors in the stainless steel group was significantly in ences among the 3 groups were observed. Other trace metals creased (p < 0.05) compared to controls. Moreover, the stainless that showed no differences included: aluminum, barium, beryl steel group had significantly greater numbers of tumors com lium, bismuth, cadmium, calcium, cobalt, copper, lead, magne pared to the surgical gut (p < 0.02), polyglactin (p < 0.005), and sium, manganese, molybdenum, nickel, phosphorus, strontium, silk (p < 0.01) groups. Finally, polyglactin and polypropylene titanium, tungsten, vanadium, and zinc. were significantly different (p < 0.01 ). Tumor Size and Histopathology. No differences in mean DISCUSSION tumor size or histopathology were detected in small or large bowel between the different groups. All intestinal tumors were This study shows that suture materials can promote the epithelial in type and could be classified as polypoid neoplasms development of large bowel tumors in a chemically induced or adenocarcinomas according to Ward (24) and Autrup and animal model of intestinal neoplasia. Tumor enhancement was Williams (1). No differences in the varieties of tumor histopath observed locally at the site of suture placement in rat cecum ology were detected among the groups. with both slowly absorbed and nonabsorbable suture materials Fecal /3-Glucuronidase Activities. Table 4 shows activities as well as further "downstream" in the distal colon with stainless from fecal samples obtained from cecum and distal colon of each steel multifilament wire. group, including controls. The activity was significantly higher in In the cecum, nonabsorbable suture materials caused in the distal colon of the stainless steel group compared to cecum creased numbers of tumors locally, and that was statistically or distal colon of any other group as well as the cecum in the significant for both surgical silk and stainless steel wire. In same group. Other differences were not observed. addition, similar results were observed with a slowly absorbed Fecal Trace Metal Determinations.Table5 showsthe results suture material, polyglactin 910, a synthetic copolymer of glycolic

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Downloaded from cancerres.aacrjournals.org on October 5, 2021. © 1984 American Association for Cancer Research. ft N. Calderisi and H. J. Freeman and lactic acids. These results are consistent with an earlier bears no direct resemblance to operative methods ordinarily study (14), showing increased numbers of cecal tumors in di- used in gastrointestinal surgery. On the other hand, the presence methylhydrazine-treated male albino rats following creation of a of luminal metallic foreign bodies resulting from increasingly cecal diverticulum with a purse-string synthetic thread suture. widespread use of mechanical stapling devices for surgical an However, in that paper (14), severe necrosis of the cecal wall in astomoses perhaps deserves further evaluation with respect to the region of the diverticulum was seen in association with a their potential long-term effects in the pathogenesis of colon marked peridiverticular inflammatory response, a situation carcinogenesis. avoided in the present study. In a paper by Williamson ef al. (26), small and large bowel anastomoses were created in azoxy- REFERENCES methane-treated rats with silk sutures. Increased numbers of 1. Autrup. H., and Williams, G. M. Experimental Colon Carcinogenesis. Boca suture line tumors were reported. In the present study using a Raton, FL: C. R. C. Press, Inc., 1983. different carcinogen, increased numbers of tumors were seen 2. Bacon, H. E., Tse, G. N., and Herabat, T. Coexisting carcinoma with peridi- with silk sutures demonstrating an effect independently of intes verticulitis in the colon. Dis. Colon Rectum, 16: 500-503,1973. 3. Barson. A. J., and Kirk. R. S. Colonie tuberculosis with carcinoma. J. Pathol. tinal transection and subsequent anastomoses. Thus, the results 101: 289-292,1970. in this paper are consistent with previous studies, but they 4. Bauer, H. G., Asp, N. G., Oste, R., Dahlqvist, A., and Fredlund, P. E. Effect of dietary fiber on the induction of colorectal tumors and fecal .Â¡-glucuronidase indicate (on the basis of a systematic examination of several activity in the rat. Cancer Res., 39: 3752-3756,1979. specific classes of suture materials) that the presence of a foreign 5. Camacho. C. Amebic granuloma and its relationship to cancer of the cecum. body per se in the form of a surgical ligature enhances tumor Dis. Colon Rectum, 14: 12-16,1971. 6. Devroede, G. J., Taylor, W. F., Sauer, W. G., Jackman, R. J., and Stickler, G. development locally independently of surgically created bowel B. Cancer risk and life expectancy of children with ulcerative colitis. N. Engl. anastomoses. J. Med., 285:17-21, 1971. In the distal colon, significantly increased numbers of tumors 7. Fishman, W. H., Kato, K., and Anstiss, C. L. Human serum 0-glucuronidase: its measurement and some of its properties. Clin. Chim. Acta, 75: 435,1967. were also observed in the group with stainless steel cecal sutures 8. Freeman, H. J., Spiller, G. A., and Kim, Y. S. A double-blind study on the effect compared to both the control and other suture groups. A sys of purified cellulose dietary fiber on 1,2-dimethylhydrazine-induced rat colonie neoplasia. Cancer Res., 38: 2912-2917,1978. temic effect seems unlikely since increased numbers of tumors 9. Freeman, H. J., Spiller. G. A., and Kim, Y. S. A double-blind study on the effect were not seen elsewhere in either the small or large bowel (i.e., of differing purified cellulose and pectin fiber diets on 1,2-dimethylhydrazine- proximal colon). Rather, some luminal factor may be critical in induced rat colonie neoplasia. Cancer Res.. 40: 2661-2665,1980. 10. Goldin, B. R., and Gorbach. S. L. The relationship between diet and rat faecal mediating this foreign body effect in the distal large intestine. bacterial enzymes implicated in colon cancer. J. Nati. Cancer Inst. 57: 371- Initially, we wondered if this might be due to a metallic component 375, 1976. of the suture material, such as iron, being elaborated directly 11. Lambert, R. Surgery of the Digestive System in the Rat, pp. 413-419. Springfield, IL: Charles C Thomas, Publisher, 1965. into the lumen. However, subsequent detailed trace metal deter 12. Lowry, O. H., Rosebrough, N. J., Fan-, A. L., and Randall, R. J. Protein minations, including iron, demonstrated no differences. Alterna measurement with the Folm phenol reagent. J. Bioi. Chem., 793: 265-275, 1951. tively, the presence of multifilament wire may produce indirect 13. Mueller, C. E., and Thombury, J. R. Adenocarcmoma of the colon complicating effects, possibly permitting bacteria to grow quantitatively within ureterosigmoidostomy. J. Urol., 709: 225-227,1973. the interstices of the wire filaments or leading to qualitative 14. Pozharisski, K. M. The significance of nonspecific injury for colon carcinogen esis in rats. Cancer Res., 35: 3824-3830,1975. changes in their metabolic activities. Because ÃŸ-glucuronidaseis 15. Reddy, B. S., Mangat, S., Weisburger, J. H., and Wynder, E. L. Effect of high- thought to reflect metabolic activities of bowel microflora and is risk diets for colon carcinogenesis on intestinal mucosa! and bacterial .(- glucuronidase activity in F344 rats. Cancer Res., 37: 3533-3536, 1977. diet dependent (4, 10, 15, 16), it may play a role in human and 16. Reddy, B. S., Weisburger, J. H., and Wynder. E. L. Fecal bacterial .(-glucuron experimental colon carcinogenesis (1,4,10,15,16,18) and is idase. control by diet. Science (Wash. DC), 783:416-417,1974. believed to be an enzyme involved in the final activation of 17. Rubio, C. A., Nylander, G., and Wallin. B. Anastomotic tumors following partial colon resection: an experimental model. Surg. Gastroenterol., 7: 63-66,1982. carcinogens in the intestinal lumen (4, 10, 18, 21, 25). In some 18. Scudamore, C. H., and Freeman, H. J. Effects of small bowel transection, previous studies (4, 10), increased activity of this enzyme was resection, or bypass in 1,2-dimethylhydrazine-induced rat intestinal neoplasia. associated with a higher tumor incidence rate in this animal Gastroenterology, 84: 725-731,1983. 19. Shackelford, R. T., and Zuidema, G. D. Surgery of the alimentary tract. In: model. Finally, direct administration of a 0-glucuronidase inhibitor Stomach and Duodenum. Incisions, Sutures, vol. 2, pp. 535-600. Philadelphia: led to decreased colon tumor formation in rodents treated with W. B. SaundersCo., 1981. carcinogen (21). In our study, /3-glucuronidase activity was in 20. Skir, I. Mutinous carcinoma associated with fistulas of long-standing. Am. J. Surg., 75:285-289, 1948. creased only in the lumen of distal colon of the stainless steel 21. Takada, H., Hirook. T., Hiramatsu, Y., and Yamamoto, M. Effect of 0-glucu- group. If tumor enhancement bears any direct relationship to romdase inhibitor on azoxymethane-induced colonie carcinogenesis in rats. Cancer Res., 42: 331-334,1982. luminal microbial metabolism as reflected in this enzyme, the 22. Tank, E. S., Karsch, D. N., and Lapides. J. Adenocarcmoma of the colon data in this study could imply differential mechanisms for tumor associated with ureterosigmoidostomy. Dis. Colon Rectum, 76: 300-304, enhancement between cecum and distal colon, particularly for 1973. 23. Tyukov, A. I. Cancer of the large intestine in the vicinity of a foreign body. the stainless steel group. It must be emphasized, however, that Arkh. Pathol., 33: 77-79,1971. enzyme studies were done only at the time of autopsy and not 24. Ward, J. M. Morphogenesis of chemically induced neoplasms of the colon and prior to or during carcinogen administration. Further studies small intestine in rats. Lab. Invest., 30:505-513,1974. 25. Weisburger, J. H., Grantham, P. M., Horton, R. E., and Weisburger, E. K. would be required to determine if increased enzyme activity per Metabolism of the carcinogen W-2-fluorenylacetamide in germ free rats. se was responsible for increased carcinogen metabolism and Biochem. Pharmacol., 79: 151-162,1970. resultant enhanced tumor frequency. 26. Williamson, R. C. N., Bauer, F. L. R., Terpstra, O. T., Ross, J. S., and Malt, R. A. Contrasting effects of subtotal enteric bypass, enterectomy, and colectomy While this study indicates that some suture foreign body on azoxymethane-induced intestinal carcinogenesis. Cancer Res., 40: 538- materials enhance carcinogenesis in this experimental animal 543,1980. 27. Williamson. R. C. N., Davies, P. W., Bristol, J. B., and Wells, M. Intestinal model, it would be premature to extrapolate directly to conditions adaptation and experimental carcinogenesis after partial colectomy. Increased present in human intestine. The surgical procedure in this study tumor yields are confined to the anastomoses. Gut, 23: 316-325,1982.

2830 CANCER RESEARCH VOL. 44

Downloaded from cancerres.aacrjournals.org on October 5, 2021. © 1984 American Association for Cancer Research. Differential Effects of Surgical Suture Materials in 1,2-Dimethylhydrazine-induced Rat Intestinal Neoplasia

Ronald N. Calderisi and Hugh J. Freeman

Cancer Res 1984;44:2827-2830.

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