JOURNAL
OF SURGICAL
RESEARCH
23, 114- 116 (1977)
The Effect of Oxidized Regenerated Cellulose on Experimental Infected Splenotomies PETER DINEEN Surgical Bacteriology Research Laboratory, Department of Surgery, The New York Hospital-Cornell Medical Center, 525 East 68th Street, New York, New York 10021 Submitted for publication July 20, 1976
INTRODUCTION
was made in both extremities of the spleen. These measured 2 x 2 cm, and a core of In previous reports [I, 21 the effect of splenic tissue was removed. Then a plug of the hemostatic agent oxidized regenerated AGS or ORC was placed in the splenotomy cellulose (ORC) (Surgicel; Johnson & Johnsite and the splenic capsule was loosely son) on bacterial growth has been disreapproximated with an interrupted suture cussed. It has been shown that ORC does of 000 silk. Hemostasis was obtained by have a strong antibacterial activity which pressure and presumably also by the effect is most evident when the ORC is put in of the hemostatic agents. direct contact with the bacterial agents at the time of challenge to the experimental animals. This effect of ORC is thought to Challenge Procedure be primarily one of pH, but there are other After the sutures had been placed in the aspects to this which are unclear. spleen and there was no evidence of serious In an effort to further delineate some bleeding, the animals were immediately of the antibacterial activity of ORC it was challenged with 100 ml of normal saline decided to measure this in wivo in a model which contained 104 culturable units of in dogs spleens. It was elected to use the S. am-em (Giorgio)/ml intravenously. This two hemostatic agents ORC and absorbable is a penicillin-resistant coagulase-positive gelatin sponge (AGS) (Gelfoam; Upjohn strain. Each animal served as its own Co.). control. Animals were sacrificed at intervals from immediately following closure of the abdomen (considered zero time) up to 20 MATERIALS AND METHODS days. There was a total of 25 animals in the experimental group. Large mongrel dogs (40-50 kg) of either At the time of sacrifice the abdomen sex were used in the experiment. was opened under aseptic conditions, the spleen was removed, and the splenotomy Operative Procedure site and a cuff of about 2 mm of surThe dogs were anesthetized with 60 mg/ rounding spleen was removed and placed kg of sodium pentobarbital intravenously. in a homogenizing tube. Then 2 ml of An endotracheal airway was used and the distilled water were added to the tube and the spleen specimen was homoganimals were ventilated on room air. The midline incision was made under enized for 30 sec. Both splenotomy sites aseptic conditions and the spleen was de- from each animal were treated in a similar livered into the wound. The spleens in these manner. Aliquots were removed from the dogs were immense and weighed more than homogenate, appropriately diluted, and a kilo in most instances. A splenotomy plated with poured trypticase soy agar. 114 Copyright 0 1977 by Academic Press, inc. All rights of reproduction in any form reserved.
ISSN 0022.4804
PETER DINEEN: EXPERIMENTAL
INFECTED
SPLENOTOMIES
11.5
After incubation for 48 hr the number of colonies was counted. In five animals a third specimen was removed from the spleen from an area midway between the two splenotomy sites. This was a core of approximately 1 cm3. This was also treated by homogenization and dilution. This was done to give a baseline of untreated splenic tissue.
reducing the bacterial population following a challenge. The mode of antibacterial action of the ORC is not clear. In vitro most of the activity can be blocked by adding sodium hydroxide to the system. The pH of ORC in the in vitro system [I] is about 2.5. Nevertheless, a pure pH effect would not explain the varying results which ORC has in vitro against different microbial species RESULTS [l]. Nor would this clarify the in vivo antibacterial findings. However, from the studFigure 1 shows the number of colonies ies to date it is postulated that the major which were counted in the two groups from action takes place promptly at the time of the same spleen. As can be seen, the colony challenge and is not a sustained one. The counts with the ORC spenotomy site are low and remain low during the time of the question could be reasonably asked: Why experiment. In the site which contained then does the microbial census remain low throughout the period of the study as comAGS the counts are high, particularly pared to the AGS group? It is postulated during the first week following surgery, that the ORC reduces the size of the chaland then drift down to lower levels after lenge inoculum to a manageable number 20 days. which permits host defense mechanisms to In the five animals in which untreated contain the infection. splenic tissue was removed, the bacterial The site which contained AGS had no counts were essentially the same as in the evidence of antibacterial activity. In the 3-, AGS group. They ranged from lo5 to lo6 4-, and 5day range there was gross eviorganisms on Day 1 and Day 2. dence of abscess formation, but later on postchallenge the host apparently was able DISCUSSION to effect some organization of the infected From this and other studies it is apparent area and control it. that the use of oxidized regenerated celluIt should be noted that S. aureus could lose (ORC) is an effective mechanism in be cultured from normal spleen, liver, and cU-J 5 A! 13 e
t= : z
.
5
l.
.
0 : .
4
AGS site 0 ORC site
l l
:
=
.
.
(.\.
0
2
4
6
8
IO
12
14
16
I8
20
Days FIG. 1. Number of culturable units of S. aureus from two splenotomy sites following challenge at zero time. One splenotomy site contained AGS and the other ORC.
116
JOURNAL OF SURGICAL RESEARCH: VOL. 23, NO. 2, AUGUST 1977
kidney in the animals for about 36 hr after challenge. This was in a range of IO5to lo6 on Day 1 postchallenge and 10’ to 102 on Day 2. No organisms were culturable after that. SUMMARY An experimental model is described in which two splenotomy sites are made in the spleen. In one site oxidized regenerated cellulose (ORC) was placed, in the other absorbable gelatin sponge (AGS). The animals were then challenged intravenously and the number of organisms from the
splenotomy sites was measured over a period of time. The number of organisms isolated from the ORC site remained low during the 20 days of the study. The number of organisms from the AGS site was high, in the range of IOVml. REFERENCES 1. Dineen, P. Antibacterial activity of oxidized regenerated cellulose. Surg. Gynecol. Obstet. 142: 481, 1976. 2. Dineen, P. The effect of oxidized regenerated cellulose on experimental intravascular infection. Surgery, in press.
OF SURGICAL
RESEARCH
23, 114- 116 (1977)
The Effect of Oxidized Regenerated Cellulose on Experimental Infected Splenotomies PETER DINEEN Surgical Bacteriology Research Laboratory, Department of Surgery, The New York Hospital-Cornell Medical Center, 525 East 68th Street, New York, New York 10021 Submitted for publication July 20, 1976
INTRODUCTION
was made in both extremities of the spleen. These measured 2 x 2 cm, and a core of In previous reports [I, 21 the effect of splenic tissue was removed. Then a plug of the hemostatic agent oxidized regenerated AGS or ORC was placed in the splenotomy cellulose (ORC) (Surgicel; Johnson & Johnsite and the splenic capsule was loosely son) on bacterial growth has been disreapproximated with an interrupted suture cussed. It has been shown that ORC does of 000 silk. Hemostasis was obtained by have a strong antibacterial activity which pressure and presumably also by the effect is most evident when the ORC is put in of the hemostatic agents. direct contact with the bacterial agents at the time of challenge to the experimental animals. This effect of ORC is thought to Challenge Procedure be primarily one of pH, but there are other After the sutures had been placed in the aspects to this which are unclear. spleen and there was no evidence of serious In an effort to further delineate some bleeding, the animals were immediately of the antibacterial activity of ORC it was challenged with 100 ml of normal saline decided to measure this in wivo in a model which contained 104 culturable units of in dogs spleens. It was elected to use the S. am-em (Giorgio)/ml intravenously. This two hemostatic agents ORC and absorbable is a penicillin-resistant coagulase-positive gelatin sponge (AGS) (Gelfoam; Upjohn strain. Each animal served as its own Co.). control. Animals were sacrificed at intervals from immediately following closure of the abdomen (considered zero time) up to 20 MATERIALS AND METHODS days. There was a total of 25 animals in the experimental group. Large mongrel dogs (40-50 kg) of either At the time of sacrifice the abdomen sex were used in the experiment. was opened under aseptic conditions, the spleen was removed, and the splenotomy Operative Procedure site and a cuff of about 2 mm of surThe dogs were anesthetized with 60 mg/ rounding spleen was removed and placed kg of sodium pentobarbital intravenously. in a homogenizing tube. Then 2 ml of An endotracheal airway was used and the distilled water were added to the tube and the spleen specimen was homoganimals were ventilated on room air. The midline incision was made under enized for 30 sec. Both splenotomy sites aseptic conditions and the spleen was de- from each animal were treated in a similar livered into the wound. The spleens in these manner. Aliquots were removed from the dogs were immense and weighed more than homogenate, appropriately diluted, and a kilo in most instances. A splenotomy plated with poured trypticase soy agar. 114 Copyright 0 1977 by Academic Press, inc. All rights of reproduction in any form reserved.
ISSN 0022.4804
PETER DINEEN: EXPERIMENTAL
INFECTED
SPLENOTOMIES
11.5
After incubation for 48 hr the number of colonies was counted. In five animals a third specimen was removed from the spleen from an area midway between the two splenotomy sites. This was a core of approximately 1 cm3. This was also treated by homogenization and dilution. This was done to give a baseline of untreated splenic tissue.
reducing the bacterial population following a challenge. The mode of antibacterial action of the ORC is not clear. In vitro most of the activity can be blocked by adding sodium hydroxide to the system. The pH of ORC in the in vitro system [I] is about 2.5. Nevertheless, a pure pH effect would not explain the varying results which ORC has in vitro against different microbial species RESULTS [l]. Nor would this clarify the in vivo antibacterial findings. However, from the studFigure 1 shows the number of colonies ies to date it is postulated that the major which were counted in the two groups from action takes place promptly at the time of the same spleen. As can be seen, the colony challenge and is not a sustained one. The counts with the ORC spenotomy site are low and remain low during the time of the question could be reasonably asked: Why experiment. In the site which contained then does the microbial census remain low throughout the period of the study as comAGS the counts are high, particularly pared to the AGS group? It is postulated during the first week following surgery, that the ORC reduces the size of the chaland then drift down to lower levels after lenge inoculum to a manageable number 20 days. which permits host defense mechanisms to In the five animals in which untreated contain the infection. splenic tissue was removed, the bacterial The site which contained AGS had no counts were essentially the same as in the evidence of antibacterial activity. In the 3-, AGS group. They ranged from lo5 to lo6 4-, and 5day range there was gross eviorganisms on Day 1 and Day 2. dence of abscess formation, but later on postchallenge the host apparently was able DISCUSSION to effect some organization of the infected From this and other studies it is apparent area and control it. that the use of oxidized regenerated celluIt should be noted that S. aureus could lose (ORC) is an effective mechanism in be cultured from normal spleen, liver, and cU-J 5 A! 13 e
t= : z
.
5
l.
.
0 : .
4
AGS site 0 ORC site
l l
:
=
.
.
(.\.
0
2
4
6
8
IO
12
14
16
I8
20
Days FIG. 1. Number of culturable units of S. aureus from two splenotomy sites following challenge at zero time. One splenotomy site contained AGS and the other ORC.
116
JOURNAL OF SURGICAL RESEARCH: VOL. 23, NO. 2, AUGUST 1977
kidney in the animals for about 36 hr after challenge. This was in a range of IO5to lo6 on Day 1 postchallenge and 10’ to 102 on Day 2. No organisms were culturable after that. SUMMARY An experimental model is described in which two splenotomy sites are made in the spleen. In one site oxidized regenerated cellulose (ORC) was placed, in the other absorbable gelatin sponge (AGS). The animals were then challenged intravenously and the number of organisms from the
splenotomy sites was measured over a period of time. The number of organisms isolated from the ORC site remained low during the 20 days of the study. The number of organisms from the AGS site was high, in the range of IOVml. REFERENCES 1. Dineen, P. Antibacterial activity of oxidized regenerated cellulose. Surg. Gynecol. Obstet. 142: 481, 1976. 2. Dineen, P. The effect of oxidized regenerated cellulose on experimental intravascular infection. Surgery, in press.
