Biomedical subjects

M P Bubrick

Publications and source records attributed to M P Bubrick.

At least 19 recordsLinked to original sources

PubMed1995

Efficacy of radioprotective agents in preventing small and large bowel radiation injury.

PURPOSE: A variety of adjuvant treatments and cytoprotective agents have been proposed to lessen the toxicity of radiation therapy. The following study was designed to evaluate the benefit of six agents or combinations using anastomotic bursting strength as a measure of transmural radiation injury. METHODS: The 40-Gy study consisted of the following. Seventy-two male Sprague-Dawley rats were divided into eight equal groups: nonradiated control, radiated untreated control, and six radiated treated groups. The radioprotective treatments included ribose-cysteine (Rib-Cys), WR-2721, glutamine, vitamin E, MgCl2/adenosine triphosphate, and RibCys/glutamine in combination. Radiated animals received 40 Gy to the abdomen. Two weeks after radiation, all animals underwent small bowel and colonic resection with primary anastomosis. Animals were sacrificed one week postoperatively, at which time anastomoses were evaluated and bursting strengths determined. The 70-Gy study consisted of the following. The same protocol was repeated for five groups of nine rats divided into nonradiated, radiated untreated, and three radiated treated groups receiving RibCys (8 mmol/kg), RibCys (20 mmol/kg), and WR-2721. All radiated animals received 70-Gy doses. RESULTS: In the 40-Gy group, there were 10 radiation-related deaths and 6 anastomotic leaks among 70 rats studied. None of the differences between groups were significant. Nonradiated control group small bowel and large bowel anastomotic bursting pressures were significantly elevated compared with all radiated groups. Compared with radiated controls, there were significant improvements in small bowel bursting strength in the RibCys, WR-2721, RibCys-glutamine, and vitamin E groups and significant improvement in colonic bursting strength in MgCl2/adenosine triphosphate, WR-2721, and RibCys groups. In the 70-Gy group, all nine nonradiated control rats survived. All eight untreated radiated control rats died, four of eight WR-2721 animals died (P = 0.03), all RibCys (8 mmol/kg) animals died (P = 0.03), and three of nine treated with RibCys (20 mmol/kg) survived (P = 0.08). CONCLUSIONS: WR-2721 and RibCys gave consistent protection against large and small bowel radiation injury. The lower incidence of treatment-related toxicity and potentially equal or greater radioprotective effects may make RibCys more clinically useful than WR-2721.

Adenosine Triphosphate↗

PubMed1995

Malignancy, mortality, and medicosurgical management of Clostridium septicum infection.

BACKGROUND: Necrotizing Clostridium septicum infections (CSI) have a strong association with malignancy or immunosuppression. To clarify this relationship and determine how it impacted mortality, the experience with CSI at a single institution was reviewed. METHODS: Records of all patients admitted to our hospital with culture proven clostridial infection from 1966 through 1993 were reviewed. RESULTS: Among patients presenting with clinical gas gangrene, 281 had culture proven clostridial infection and 32 (11.4%) had CSI. The mortality among CSI patients was 56%, whereas 26% of all patients with clostridial infections died (p = 0.001). An associated malignancy was found in 50% of patients with CSI, whereas this was seen in only 11% of patients with other clostridial infections (p = 0.0001 for CSI versus clostridial infection overall). The remaining patients with spontaneous CSI all had evidence of immunosuppression. CONCLUSIONS: The high mortality and likelihood of associated malignancy or hematologic disease underscore the importance of a high index of suspicion and the need to search for and treat associated conditions in all patients with CSI.

Adenocarcinoma↗

PubMed1995

Endotoxin pretreatment of human monocytes alters subsequent endotoxin-triggered release of inflammatory mediators.

In trauma or sepsis, monocytes and macrophages release mediators such as tumor necrosis factor (TNF), interleukin-1 (IL-1), interleukin-6 (IL-6), and prostaglandin E2 (PGE2). Although patients may be exposed to more than one stimulus, the effect of repetitive endotoxin (LPS) stimulation on human monocytes is poorly characterized. Human peripheral blood monocytes obtained from healthy volunteers were pretreated with endotoxin (LPS1) for 24 h. Cultures were then restimulated for 24 h with a second, activating LPS stimulus (LPS2) at various concentrations and supernatant mediators (TNF, IL-1, IL-6, and PGE2) measured. Serum cytokine levels of normal monocyte donors were compared to basal and LPS-stimulated cytokine release of their monocytes in vitro. LPS2 increased all mediators in a dose-dependent manner in the absence of LPS1 pretreatment. LPS1 significantly increased LPS2-triggered monocyte secretion of IL-1, IL-6, and PGE2, but inhibited TNF release. Cell-associated TNF and IL-1 were also inhibited and enhanced in parallel with supernatant levels of the respective cytokines. Serum cytokine levels were low, showed wide variation, and correlated poorly with in vitro LPS-triggered cytokine production. Human monocyte mediator production is differentially regulated by endotoxin pretreatment. Provocative in vitro testing of monocytes could identify prior LPS exposure and may be more useful than serum cytokine measurements.

Adult↗

PubMed1995

A comparative study of open, laparoscopic intracorporeal, and laparoscopic assisted low anterior resection and anastomosis in pigs.

This study was done to investigate whether laparoscopic intracorporeal (LI) or laparoscopic assisted (LA) colon resection results in improved anastomotic healing compared with open colon resection (OR). Thirty-six domestic swine were randomly assigned to undergo either LI, LA, or OR of the rectosigmoid. For OR cases, the sigmoid was resected through a midline incision, and a transanal end-to-end stapled anastomosis was constructed with an ILS device. For LA and LI cases, the sigmoid was laparoscopically mobilized and divided distally, using 5 trocar sites. For LA cases, the proximal sigmoid was brought out through an enlarged trocar site and resected; the ILS anvil was secured to the proximal end, and the colon was replaced in the abdominal cavity where the anastomosis was completed by transanal insertion and firing of ILS device. For LI cases, the sigmoid was resected laparoscopically and retrieved through a 33 mm trocar. The ILS anvil was introduced via the same trocar, and the device was laparoscopically secured with two Endoloop (Ethicon Endo-Surgery, Cincinnati, OH) pursestring sutures. The anastomosis was completed the same way as for LA cases. Animals were killed at 7 days, at which time the anastomoses were evaluated by barium enema, bursting pressure, and histologic appearance. There were no radiographic anastomotic leaks. The mean bursting pressure was 205 +/- 65 mmHg for the 13 OR animals, 240 +/- 53 mmHg for 11 LA animals, and 242 +/- 43 mmHg for the 12 LI animals (N.S.). Histologic evaluation for inflammation indicated no significant differences.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗

PubMed1994

Macrophage endotoxin tolerance. Tumor necrosis factor and interleukin-1 regulation by lipopolysaccharide pretreatment.

OBJECTIVE: To correlate cytokine gene expression with the release of protein product by murine peritoneal macrophages rendered tolerant by sequential endotoxin stimulation in vitro. DESIGN: In vitro investigation of the regulation of endotoxin-stimulated cytokine production following endotoxin pretreatment using cytokine bioassays, polymerase chain reaction, and Northern blot analyses. SETTING: In vitro cell culture model of sequential endotoxin stimulation of murine macrophages. INTERVENTIONS: Macrophages were pretreated with 0 or 100 ng/mL of lipopolysaccharide (LPS1) for 24 hours and then stimulated with 0 or 100 ng/mL of LPS (LPS2) for 4 or 24 hours. After stimulation, supernatant tumor necrosis factor (TNF) and interleukin-1 (IL-1) levels were measured by bioassay. Total RNA was extracted and messenger RNA (mRNA) corresponding to TNF and IL-1 was amplified by reverse transcription-polymerase chain reaction or analyzed by Northern blot. RESULTS: Endotoxin pretreatment resulted in the augmentation of IL-1 (mean +/- SD, 78 +/- 9 vs 596 +/- 42 pg/mL, P < .01) and the inhibition of TNF (274 +/- 63 vs 61 +/- 3 pg/mL, P < .01) release 4 hours after stimulation with 100 ng/mL of LPS2. A similar pattern of cytokine release was observed 24 hours after LPS2 stimulation. Pretreatment produced an increased IL-1 message in response to 100 ng/mL of LPS2. The TNF message was detectable in all groups receiving LPS2 alone, but the highest levels of TNF mRNA were seen in LPS1-pretreated cells stimulated with LPS2. CONCLUSIONS: Endotoxin pretreatment produced increased IL-1 message that paralleled the augmentation of IL-1 protein, whereas abundant TNF message was present even though TNF protein release was significantly inhibited. In this model of in vitro endotoxin tolerance, pretreatment initiates divergent pathways of cytokine regulation.

Animals↗

PubMed1994

The use of biodegradable amikacin microspheres to prevent vascular graft infection.

The following study was performed to determine if an antibiotic impregnated in a biodegradable polymer can prevent infection and eradicate inoculum bacteria from contaminated polytetrafluoroethylene vascular grafts. Poly(glycolide-co-dl-lactide) amikacin microspheres (PAM) measuring 50-100 microns were designed to deliver 100 mg (PAM 100) or 300 mg (PAM 300) amikacin per unit dose. Twenty mongrel dogs had a short segment of infrarenal aorta replaced with a graft that had been bathed in a 2 cc solution of Escherichia coli and Staphylococcus aureus (3 x 10(8) CFU/ml). Dogs were divided into three groups: Controls had contaminated grafts placed and received no therapy; PAM 100 and PAM 300 were used, respectively, to cover the grafts in the other two groups. Animals were sacrificed 14 days postoperatively at which time grafts were examined and cultured. Among controls, 7/8 had clinical graft infections and all had positive cultures for S. aureus (8/8) or E. coli (5/8). None of the treated animals had clinical graft infections (P < 0.001). Positive cultures were obtained for S. aureus in 2/8 (P < or = 0.007) and E. coli in 0/8 (P < or = 0.03) PAM 100 dogs and for S. aureus in 0/8 (P < or = 0.0002) and E. coli in 0/8 (P < or = 0.03) PAM 300 dogs. Two PAM 100 and four PAM 300 dogs had rare growth of contaminant bacteria (NS). In conclusion, PAM can prevent clinical graft infection and completely eradicate a standardized bacterial inoculum.

Amikacin↗

PubMed1994

Pre-exposure to hypoxia or septic stimuli differentially regulates endotoxin release of tumor necrosis factor, interleukin-6, interleukin-1, prostaglandin E2, nitric oxide, and superoxide by macrophages.

UNLABELLED: Shock states with resulting inadequate cellular oxygen delivery may contribute to macrophage (M phi) activation or dysregulation. In this study we compared the effects of transient anoxia and endotoxin pretreatment (LPS1) on M phi mediator release with a second endotoxin stimulus (LPS2). METHODS: In vitro cultures of murine peritoneal exudate M phi were exposed to 2 hours of hypoxic or normoxic conditions, then incubated 22 hours under identical normoxic conditions +/- 10 ng/mL of LPS1 pretreatment. During the final 24 hours all M phis were exposed to a range of LPS2 concentrations. The M phi supernatants were assayed for tumor necrosis factor (TNF), interleukin 1 (IL-1), interleukin 6 (IL-6), prostaglandin E2 (PGE2), nitric oxide (NO), and superoxide release. RESULTS: LPS1 markedly inhibited M phi TNF release by LPS2, but hypoxia had no effect on LPS2-triggered TNF release. Hypoxia increased M phi IL-6 production in the absence of LPS1, but inhibited the LPS1 augmentation seen under normoxic conditions. Pretreatment with LPS1 increased NO production from LPS2 under normoxic conditions, but hypoxia inhibited this effect. Superoxide production increased by LPS1 under normoxic conditions, but hypoxia significantly inhibited superoxide release. CONCLUSIONS: The effects of transient anoxic exposure on LPS2-triggered M phi function are markedly different from the effects of pretreatment with septic stimuli (LPS1).

Analysis of Variance↗

PubMed1993

Comparison of bursting pressure of sutured, stapled and BAR anastomoses.

The study was undertaken to compare anastomotic bursting pressure (ABP) of colorectal canine anastomoses using three different anastomotic techniques. Biofragmentable anastomotic ring (BAR), stapled, and sutured colon anastomoses were sequentially placed in each of 48 dogs following division of the colon at three equally spaced sites. Four groups of 12 dogs were sacrificed either on day 0, 3, 7, or 28 and ABP and bursting wall tension were determined. The data revealed that BAR anastomoses have the greatest strength on the day of surgery, sutured anastomoses are the strongest on the third day and all are comparable by the 7th day. Bursting pressures for all groups by day 28 approach normal colonic bursting pressure, with any differences likely to be a reflection of variation in anastomotic fibrosis and other factors.

Anastomosis, Surgical↗

PubMed1993

Protective effect of RibCys following high-dose irradiation of the rectosigmoid.

UNLABELLED: Ribose-cysteine (RibCys) is a prodrug of L-cysteine that stimulates glutathione biosynthesis. Increased glutathione levels have been shown to have a protective effect against radiation-induced injury and oxidative stress. Surface oximetry has previously been used successfully to predict anastomotic leakage. PURPOSE: The following study was done to evaluate the protective effect of RibCys and the predictive value of PtO2 determinations in a swine model. METHODS: Domestic swine were divided into three groups: Group A served as a nonradiated control; Group B received 6,000 to 6,500 rad to the rectosigmoid; and Group C received RibCys (1 g/kg) prior to receiving 6,000 to 6,500 rad. Radiated animals and controls underwent rectosigmoid resection after a three-week rest period. Intraoperative anastomotic PtO2 was checked with a modified Clark electrode. Anastomoses were evaluated radiographically at three and seven days; animals were sacrificed, and bursting strength was recorded at 10 days. RESULTS: Mean bursting pressures were 243.8 +/- 59.4, 199.5 +/- 37.8, and 209.5 +/- 54.9 mmHg (NS) for Groups A, B, and C, respectively. Anastomotic PtO2 ranged from 19 to 98 mmHg and could not be correlated with anastomotic leaks or bursting pressure. There were 11/15 radiation-related deaths and leaks (eight deaths and three leaks) in the radiated group and 4/12 radiation-related deaths and leaks (three deaths and one leak) in the group receiving radiation and RibCys (P < 0.04). CONCLUSIONS: 1) RibCys protected animals against radiation-related deaths and anastomotic leaks following high doses of pelvic irradiation; 2) anastomotic PtO2 levels did not correlate with anastomotic healing in this model.

Anastomosis, Surgical↗

PubMed1993

Autoregulation of hepatic macrophage activation in sepsis.

Endotoxin (LPS)-stimulated macrophages release mediators, such as tumor necrosis factor (TNF) and prostaglandin E2 (PGE2), which modulate the function of many different cells. We hypothesize that macrophage regulation is altered in sepsis and that mediators from LPS-stimulated macrophages "autoregulate" their activation state. Alterations in the LPS dose response relationships for inhibition of hepatocyte protein synthesis by hepatic macrophages (hMøs) were examined to investigate factors that regulate hMø activation. In vitro pretreatment was compared using TNF alpha, PGE2, subactivating concentrations of LPS, or LPS plus indomethacin. Pre-exposure to LPS resulted in a dose-dependent loss of subsequent LPS-triggered activation of hMøs in co-culture. Pretreatment with LPS and 1 mumol/L indomethacin partially restored hMø responsiveness. Pre-exposure to PGE2 significantly decreased LPS responsiveness of co-cultured hMøs, suggesting that PGE2 produced by LPS-stimulated hMøs may mediate this effect. Pretreatment of hMøs with TNF alpha, but not IL-1 beta, significantly lowered the LPS concentration required for maximal hMø activation. We conclude that both macrophage mediators and LPS pretreatment alter macrophage activation state. These data suggest an "autoregulatory" role for mediators of LPS-stimulated macrophages in sepsis.

Bacterial Infections↗

PubMed1993

Anatomical and morphological evaluation of pacemaker lead compression.

In recent years, pacemaker lead failure due to compressive damage has been reported with increasing frequency. To document the mechanism of this failure, we evaluated explanted mechanically damaged leads with electrical testing, optical microscopy, and in some cases, scanning electron microscopy (SEM). In addition, we performed an autopsy study to measure the compressive loads on catheters placed percutaneously through the costoclavicular angle, as well as by cephalic cutdown. Of the 49 explanted compression damaged leads with enough clinical data for analysis, all had been placed by percutaneous subclavian puncture. Our autopsy data confirmed the significant increase in pressures generated in the costoclavicular angle for medial percutaneous subclavian catheterization (126 +/- 26 mmHg) compared to a more lateral percutaneous subclavian puncture (63 +/- 15 mmHg) or a cephalic cutdown (38 +/- 13 mmHg) (P < 0.01). In vivo coil compression testing documented loads up to 100 pounds per linear inch of coil and a compressive morphology by SEM identical to that seen in the clinical explants. Pacemaker leads appear to be susceptible to compression damage when placed by subclavian venipuncture. When possible, leads should be placed such that they avoid the tight costoclavicular angle.

Bloodletting↗

PubMed1992

Survival after emergency department versus operating room thoracotomy for penetrating cardiac injuries.

The authors undertook a 6-year retrospective review to assess their experience with penetrating cardiac injuries. Special emphasis was placed on identifying patients with and without tamponade and those requiring emergency department (ED) thoracotomy. Forty-eight patients were identified. Overall survival was 64.6 per cent. Thirty-three patients had tamponade, with 20 requiring ED thoracotomy. Fifteen patients did not have tamponade and two of these needed ED thoracotomy. Five patients who had ED thoracotomy were long-term survivors (22.7%). The remaining 26 patients, 13 with tamponade and 13 without, received operating room (OR) thoracotomy and all survived. The data shows that excellent results are possible with OR thoracotomy for penetrating cardiac injuries, with or without tamponade. However, results are not as good when ED thoracotomy is necessary. This may relate to the severity of the injury, the duration of tamponade, or the inability to control cardiac bleeding during thoracotomy in the ED setting. Even though survival is low with ED thoracotomy, it is high enough to continue to support its use in the deteriorating patient with a penetrating cardiac wound.

Adolescent↗

PubMed1991

Comparative intrinsic and extrinsic compliance characteristics of S, J, and W ileoanal pouches.

Although compliance of the ileoanal reservoir pouch has been shown to affect function, previous compliance studies may have been influenced by the compliance of the small bowel proximal to the pouch and by supporting pelvic structures. The following study was designed to isolate the pouch and to compare intrinsic and extrinsic factors influencing pouch compliance. Thirty-three mongrel dogs underwent rectal mucosectomy and proctocolectomy with S-pouch (S) in nine, stapled J-pouch (SJ) in nine, handsewn J-pouch (HJ) in nine and handsewn W-pouch (SW) in six. At 2 weeks, each dog underwent laparotomy, the small bowel 2 cm proximal to the pouch was clamped, and in vivo pouch compliance was measured using anal balloon occlusion and continuous saline infusion manometry. The pouch was then removed and ex vivo measurements were repeated. Mean compliance slopes between 0 and 40 cm H2O were compared by ANOVA and paired t-tests. In vivo and ex vivo compliance in ml/cm H2O was 3.1 +/- 1.2 and 3.8 +/- 1.6 (P = 0.25) for the S-pouch, 3.1 +/- 0.6 and 5.2 +/- 1.7 (P less than 0.01) for the SJ-pouch, 2.3 +/- 0.5 and 4.8 +/- 0.7 (P less than 0.001) for the HJ-pouch, 3.6 +/- 0.6 and 6.0 +/- 0.7 (P less than 0.001) for the W-pouch. Pearson's correlation coefficient for in vivo and ex vivo measurements of the S, SJ, HJ, and W pouches were r2 = 0.066, 0.001, 0.039, and 0.379, respectively. It is concluded that: 1) Isolated pouch compliance can be accurately measured in experimental animals with proximal and distal occlusion and inflow manometry. 2) In vivo compliance is significantly less in the HJ compared with S, SJ, and W pouches. 3) Differences between in vivo and ex vivo compliance of SJ, HJ, and SW pouches are significant. 4) In vivo and ex vivo compliance determinations correlate poorly. 5) Extrinsic factors contribute significantly to pouch compliance.

Anal Canal↗

PubMed1991

Prospective, randomized trial of the biofragmentable anastomosis ring. The BAR Investigational Group.

A randomized trial was undertaken to compare the biofragmental anastomotic ring (BAR) with conventional intraperitoneal colorectal anastomotic techniques. Patients were randomized into one of two schemes: BAR versus sutured or BAR versus stapled anastomosis. There were 782 patients entered into the study and 283 patients (36%) had a sutured anastomosis, 104 patients (13%) had a stapled anastomosis, and 395 (51%) had the BAR. Comparison of the BAR with combined suture and stapled controls revealed no significant differences in wound complication, abscess rate, bleeding, anastomotic leaks, ileus, obstruction, or deaths. There were no differences in return of bowel function, return to normal diet, or hospital stay. Intraoperative difficulties occurred in 46 BAR patients (17%), and this was significantly higher (p less than 0.001) than for sutured (3%) but not for stapled anastomoses (11%). The occurrence of these problems did not adversely effect the outcome. The data suggest that the BAR is a safe, satisfactory alternative to sutured or stapled colorectal anastomoses.

Adolescent↗

PubMed1991

Iron chelation with a deferoxamine conjugate in hemorrhagic shock.

Oxygen-derived radicals are cytotoxic, highly reactive molecules that contribute to cellular death and injury in hemorrhagic shock. Iron released into the plasma in hemorrhagic shock may contribute to cellular damage by catalyzing lipid peroxidation of cell membranes. Deferoxamine (DFO) chelation of transitional metal ions prevents formation of these radicals and may diminish reperfusion injury. The conjugation of DFO to pentastarch (PS) decreases DFO toxicity and extends its half-life making it a potentially useful resuscitative fluid. A porcine hemorrhagic shock model was used to evaluate the effects of five resuscitative fluids on survival and hepatic function. Swine (11-16 kg) underwent splenectomy, liver biopsy, and placement of arterial and venous catheters. Awake animals were bled at 1 ml/kg/min to a MAP of 45 mm Hg, maintained for 1 hr, and resuscitated over 30 min with one of five fluids: Lactated Ringer's (LR); LR + free DFO 2.5 mg/ml (LR + DFO) (n = 6); 5% PS in LR (PS) (n = 6); 5% PS + free DFO (PS + DFO) 7.5 mg/ml (n = 6); 5% PS/DFO conjugate (7.5 mg/ml) in LR (n = 6). LR and LR + DFO received 3 ml/ml shed blood; PS, PS + DFO, and PS/DFO received 1 ml/ml shed blood. No shed blood was returned to the animals. There was no significant differences between groups in MAP, HR, CVP, and T pre- and post-resuscitation. No LR lived to sacrifice at 24 hr. Thirty-three percent of LR + DFO and PS + DFO animals died within minutes of receiving the free DFO containing resuscitative fluid, presumably from acute DFO toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Management of dialysis-associated steal syndrome complicating upper extremity arteriovenous fistulas: use of intraoperative digital photoplethysmography.

Dialysis-associated steal syndrome (DASS) occurring after creation of arteriovenous fistulas often necessitates ligation of the fistula. From June 1987 to June 1990, a total of 542 upper extremity arteriovenous fistulas were constructed: radiocephalic fistulas in 182 patients, 325 forearm loop grafts and 32 upper arm loop grafts. We managed 27 patients with DASS including two patients who were referred from other hospitals. DASS developed in two patients (1%) with radiocephalic fistulas and in 23 patients (6.4%) with arteriovenous grafts. Of the 27 patients, the fistula was ligated in nine because of tissue loss, severity of symptoms, or absence of improvement in digital pressure with the fistula occluded. Intraoperative digital photoplethysmography was used to guide the amount of graft narrowing in 16 patients. The goal was to obtain a digital blood pressure of 50 mm Hg or digital to brachial ratio of more than 0.6. Ten of the 16 patients had satisfactory graft function for more than 6 months, and all patients had improvement or resolution of the steal syndrome. We conclude that DASS is an uncommon complication of upper extremity arteriovenous shunts and narrowing of the fistula and that using intraoperative digital photoplethysmography as a guide is a useful method for relieving the steal syndrome and salvaging the shunt.

Adult↗

PubMed1991

Controlled expansion of peripheral nerves: comparison of nerve grafting and nerve expansion/repair for canine sciatic nerve defects.

The inherent disadvantages of nerve grafting have made it necessary to find alternative techniques for treating segmental nerve loss. This study compares the techniques of nerve grafting and nerve expansion/repair for the management of nerve injuries with segmental nerve loss in an animal model. Bilateral segmental sciatic nerve defects were created in eight dogs. On one side a 2-cm segment was excised and replaced with a nerve graft; on the other side a 2-cm defect was created with ligatures and the nerve underwent preliminary expansion and then repair. Eighteen months later nerve conduction velocity (NCV), gastrocnemius contraction force (GCF), and muscle weight (GMW) were determined for the seven surviving animals. NCV for the expanded repair was 58.66 +/- 34.18 m/sec and 47.73 +/- 7.93 for the grafted repair (p = 0.4); GCF was 619.04 +/- 353.70 gm for the expanded repair and 726.80 +/- 415.78 gm (p = 0.2) for the grafted repair; and GMW was 82.80 +/- 5.68 gm for the expanded repair and 109.55 +/- 20.63 gm (p = 0.02) for the grafted repair. The data suggest that: 1) conventional tissue expansion techniques can be used successfully to repair segmental peripheral nerve defects; 2) NCV and GCF are comparable for grafting and expansion/repair techniques although GMW is significantly higher in the grafted group; and 3) nerve expansion/repair may prove to be a useful alternative to grafting.

Action Potentials↗

PubMed1990

Experience with the biofragmentable anastomotic ring (BAR) in bowel preoperatively irradiated with 6000 rad.

Previous studies from the authors' laboratory using the biodegradable anastomotic ring (BAR) have demonstrated the safety of this device in animals irradiated preoperatively with the equivalent of 5000 rad; sutured, stapled, and BAR anastomoses all had leak rates of 10 percent or less in this setting. This study was undertaken to assess the safety of the BAR after irradiation with the equivalent of 6000 rad. Thirteen mongrel dogs underwent preoperative irradiation to the rectum and rectosigmoid, receiving 6000 rad according to the nominal standard dose equation. After a three-week rest period, each dog underwent anterior resection of the rectosigmoid and anastomosis with the BAR. The anastomoses were evaluated for early and late healing and anastomotic leaks. The results were compared with previous data from the authors' laboratory using an identical model. Radiographic leaks were found in 7 of 10 sutured anastomoses, 8 of 10 stapled anastomoses, and 3 of 13 BAR anastomoses (P less than 0.01). Comparative clinical leaks were 5 of 10 for sutured, 5 of 10 for stapled, and 3 of 13 for BAR anastomoses. These data suggest that the BAR may offer added safety to an anastomosis after preoperative irradiation. Whether this effect is due to the atraumatic technique of placing the device, improved blood flow to the anastomotic margins, or other factors, is still underdetermined.

Anastomosis, Surgical↗