James B. Peoples

The role of glutamine in skeletal muscle ischemia/reperfusion injury in the rat hind limb model

OBJECTIVES Ischemia/reperfusion injury is a commonly occurring event with severe pathologic consequences. Reperfusion initiates both the local and systematic damage in part through rapid oxygen generation. The glutathione system is a major mechanism of reducing this oxidative stress. If this system can be maintained or augmented during this stress then less damage may occur. Glutamine provides the source of glutamate to this system and has been shown to preserve total glutathione levels after injury/ischemia to both hepatic and gut models. To test this effect, we looked at glutamine and its role in ischemia/reperfusion injury in a rat hind limb model. METHODS Fifty male HSD/Holtzman rats weighing 350-400 g were randomized to receive glutamine (3% sol) or normal saline via intraperitoneal injections. The groups were then subjected to 2 hours of ischemia to their hind limbs using the Tourni-Cot method. Animals were then randomized to reperfusion groups of 30 minutes, 2 hours, and 4 hours. Muscle tissue assays were performed for lipid peroxidation (LPO), total glutathione (GSH), and myeloperoxidase (MPO). Peripheral blood was analyzed for creatinephosphokinase levels (CPK). RESULTS Animals that received glutamine showed a general trend of less lipid peroxidation products than the normal saline groups. In animals that received glutamine and underwent 2 hours of ischemia and reperfusion times of 0 minutes, 30 minutes, and 2 hours, there were significantly less percent changes in lipid peroxidation products from controls (4.6% vs 48.2%, P <0.05), (18.9% vs 123%, P <0.05), (12.6% vs 115%, P <0.05). A general trend upward was noted in CPK levels in both groups. In animals receiving 2 hours of ischemia and 30 minutes of reperfusion, there was a significantly greater level of creatinephosphokinase (CPK) calculated as percent change from control in the normal saline group as compared with the glutamine group (209.2% vs 92.7%). Myeloperoxidase assay of muscle tissue revealed a progressive increase as the reperfusion times grew. In animals receiving 2 hours of ischemia and 30 minutes of reperfusion, the normal saline group had a significantly larger percent increase from controls than the group that received glutamine (1126.4% vs 108%, P <0.05). Also, in those animals receiving 4 hours of reperfusion, the normal saline group had a significantly higher percent increase in MPO content than the glutamine group (6245% vs 108%, P <0.05). Total glutathione levels decreased rapidly as reperfusion occurred in both the normal saline and glutamine groups. No significant difference between the groups was noted. CONCLUSIONS Total glutathione levels during reperfusion were not significantly different in the groups receiving glutamine versus normal saline. Glutamine may provide an initial protective effect on reperfusion injury after moderate reperfusion times in the hind limb model as defined by CPK and LPO levels. Glutamine may blunt neutrophil recruitment after longer reperfusion times (4 hours) in the ischemic hind limb. Total glutathione levels decreased significantly after moderate levels of ischemia (2 hours) and reperfusion (30 minutes, 2 hours).

Are pancreatoenteric anastomoses improved by duct-to-mucosa sutures?☆

The patency of anastomoses joining the pancreas to either a Roux-Y loop of jejunum or the stomach was evaluated in 26 dogs. At a preliminary operation, the head and uncinate process of the pancreas were resected while carefully preserving the duodenal blood supply. The remaining body and tail of the pancreas were totally obstructed. After obstruction for a mean of 22 (range: 6 to 42) days, one of three anastomoses was performed: (1) inversion pancreatogastrostomy with two layers of sutures; (2) a similar inversion pancreatojejunostomy to the side of a Roux-Y jejunal loop; or (3) pancreatojejunostomy in which the major duct was joined to the jejunal mucosa with interrupted sutures. Six animals were kept for controls. Anastomotic patency was assessed after 8 to 12 weeks by pancreatography, with minimal pressures to achieve anastomotic flow recorded. Weight trends were consistent with anastomotic status. The eight dogs with duct-to-mucosa sutures clearly achieved superior anastomotic patency.

Craniofacial trauma in injured motorcyclists: The impact of helmet usage

Helmets are effective in decreasing maxillofacial trauma in motorcycle crashes. The impact, however, of motorcycle crashes on the location and patterns of craniofacial injuries among helmeted versus unhelmeted patients has not been examined. In the present study, 331 injured motorcyclists were evaluated to compare the incidence of craniofacial and spinal injury in 77 (23%) helmeted and 254 (77%) nonhelmeted patients. Nonhelmeted motorcyclists were three times more likely to suffer facial fractures (5.2% vs. 16.1%) than those wearing helmets (p < 0.01). Skull fracture occurred in only one helmeted patient (1.2%), compared with 36 (12.3%) of nonhelmeted patients (p < or = 0.01). The incidence of spinal injury was not significantly different between the two groups. Blood alcohol levels demonstrated that 12% of the helmeted group were legally intoxicated (blood alcohol level > 100 mg/dL), in contrast to 37.9% of the nonhelmeted motorcyclists (p < or = 0.01). Failure to wear a helmet resulted in a significantly higher incidence of craniofacial injury among patients involved in motorcycle crashes, but did not affect spinal injury or mortality. Alcohol usage seemed to correlate with failure to use helmets. Helmet use should be legally mandated on a national level for all motorcyclists.

Incidental Meckel's diverticulectomy in adults

BACKGROUND Incidental Meckels diverticulectomy has been advocated by some surgeons because of the lower associated morbidity and mortality in this setting than when resection is indicated. Others have argued that the low risk of complication occurrence does not justify prophylactic removal. The issue remains controversial. METHODS Medical records of all adults undergoing Meckels diverticulectomy at four acute care hospitals during the 5-year period 1989 through 1993 were retrospectively reviewed. Decision analysis was used to determine relative risks for incidental resection compared to indicated resection for a complication. RESULTS Ninety patients underwent incidental diverticulectomy. Morbidity was 2% and mortality 0%. Four patients underwent resection for a complication of their diverticulum. Morbidity and mortality were each 0%. Combining these results with previously reported results and using decision analysis, the conditional probabilities of producing surgical morbidity or mortality in the adult population at risk by only resecting symptomatic diverticula are 0.2% and 0.04%, respectively. The comparable risks for resecting all incidentally discovered diverticula are 4.6% and 0.2%. CONCLUSIONS Incidental diverticulectomy in adults should be abandoned.

Reassessment of primary resection of the perforated segment for severe colonic diverticulitis

Primary resection with colostomy has been widely adopted during the past decade for the treatment of patients with severe complications of diverticulitis. Because of this, a retrospective review was performed of all patients undergoing surgery for colonic diverticular disease during the two time periods 1974 to 1978 (n = 196) and 1982 to 1986 (n = 230). Forty-three patients had abscess or peritonitis from 1974 to 1978, whereas 52 had these complications from 1982 to 1986. Colostomy and drainage alone were used for 31 of 43 patients (72%) from 1974 to 1978, while primary resection with colostomy was used for 39 of 52 patients (75%) from 1982 to 1986 (p less than or equal to 0.5). Despite this shift in treatment method, mortality increased from 14% in 1974 to 1978 to 19% in 1982 to 1986 (p = NS). Patients with peritonitis had identical mortalities (22%) during both intervals. Patients with abscess experienced an increase in mortality from 8% in 1974 to 1978 to 15% in 1982 to 1986 (p = NS). The widespread use of primary resection for patients with severe complications of diverticulitis appears not to have altered mortality for those with diffuse peritonitis and may have worsened the outcome for those with abscess.

Operative therapy for sigmoid volvulus

The medical records of 54 patients treated for sigmoid volvulus from 1983 to 1987 were reviewed. Patient demographics were very similar to previously published results. Four patients (7.4 percent) underwent emergency resection for gangrene with a mortality of 75 percent. Of the 50 patients who presented without ischemia, 23 (46 percent) were managed by nonoperative detorsion while 3 (6 percent) detorsed spontaneously. Fourteen of these 26 patients received no further treatment. Nonoperative mortality was 0 percent. Celiotomy was performed on 36 patients. The type of operative procedure performed had no significant bearing on outcome. Fifteen patients underwent resection and anastomosis; two of these patients died (13 percent). Fifteen patients underwent resection and colostomy with two deaths (13 percent), and six had open detorsion alone with one death (17 percent). The two factors associated with adverse outcome after surgical intervention were patient age and history of previous volvulus. All five deaths occurred in patients older than 70 years presenting with a first episode of volvulus (N=15, mortality=33 percent). No deaths occurred among patients younger than 70 years regardless of volvulus history or among those older than 70 years who were being treated for a recurrence (P≤0.01). Patients older than 70 years with a first episode of volvulus represent a high risk if subjected to surgical intervention. Nonoperative detorsion alone should be considered for this subgroup of patients.

Combined use of topical and systemic antibiotics

An animal wound model was used to compare the effectiveness of topical and systemic antibiotics and to examine the validity of using a combined regimen of both routes of antibiotic delivery. Gross infection rates and wound bacterial concentrations were determined after contamination with Staphylococcus aureus or Escherichia coli. Both moderate (10(8) colony-forming units [CFU]) and heavy (10(12) CFU) contamination were studied for each organism. Following moderate contamination, topical and systemic antibiotics were equally effective in reducing both wound bacterial content and infection rate, but there was no benefit from the combined use of both modes of antibiotic delivery. An additive effect of the combined regimen was noted only when the level of wound contamination was heavy.

The deltopectoral triangle as a landmark for percutaneous infraclavicular cannulation of the subclavian vein

An anatomic landmark is identified and described that simplifies the tech nique of central venous cannulation via the subclavian vein. The commonly used techniques are an approach to the subclavian at the junction of the medial and middle thirds of the clavicle or at the midclavicular line. A described ana tomic landmark, the deltopectoral triangle, is easily identified in virtually all patients and requires no measuring or extensive knowledge of anatomy for lo calization. Penetration of the skin at this landmark facilitates the procedure and produces less patient discomfort. Using this technique, the authors have suc cessfully cannulated the subclavian vein in 92.7% (51/55) of attempts with a 5.5% (3/55) complication rate. The only complications were arterial punctures, which were treated with pressure and were of no consequence to the patient.

Prevention of hypocalcemia by administration of homologous plasma during experimental hemorrhagic pancreatitis in the pig.

Pancreatitis was induced in fifteen immature pigs while five additional pigs underwent sham laparotomy. Animals with pancreatitis were separated into three groups of five each with respect to fluids administered after pancreatitis was induced. Each pig in group A and the control group received normal saline, 300 ml/hour for 8 hours. Pigs in group B received pig plasma at 150 ml/hour plus normal saline at 150 ml/hour for 8 hours. Pigs in group C received pig plasma at 50 ml/hour plus normal saline at 50 ml/hour for 24 hours. Values for serum hematocrit total protein, and total calcium, were measured preoperatively and 4, 8, and 24 hours postoperatively. Control animals and group B animals experienced no change in any parameter. Group A, animals sustained transient severe hemoconcentration, permanent severe hypoproteinemia, and hypocalcemia. Group C animals displayed a transient moderate hemoconcentration and a moderate but sustained decrease in calcium concentration. It is concuded that the hypocalcemia occurring during experimental hemorrhagic pancreatitis is directly related to the early hypovolemia and can be prevented by preventing the hypovolemia.

Adjunctive vasodilator therapy in the treatment of murine ischemia

Potent vasoconstrictors such as angiotensin II and vasopressin have been implicated as mediators of persistent vasoconstriction after reversible superior mesenteric artery (SMA) occlusion. Neither captopril (CAP), an angiotensin-converting enzyme (ACE) inhibitor, nor papaverine (PAP), a vasodilator, has proven effective in reversing this vasoconstriction when employed singly. The present study examined the combined effect of these agents in reducing mortality in a murine model of acute mesenteric ischemia. The SMAs of 106 adult male Sprague-Dawley rats were totally occluded for 85 minutes. Test agents were given intravenously at reperfusion over a 90-minute period. Survival rates were assessed at 48 hours. CAP was given as a single bolus (0.3 mg/kg) and PAP (0.5 mg/kg/h) as an infusion. Aortic and SMA blood flows were measured pretreatment and posttreatment in a separate group of 19 animals treated with CAP and PAP as single agents. chi 2 analysis and analysis of variance were used to test differences with p < or = 0.05 accepted as significant. PAP alone as an adjunct resulted in a significant increase in 48-hour survival (57% versus 19%, p < or = 0.005). PAP in combination with CAP produced the best outcome in this model (87% versus 19%, p < or = 0.005). Aortic blood flow decreased, whereas SMA blood flow increased after treatment both with CAP and with PAP, but not significantly. The combination of an intravenously administered vasodilator with either glucagon or an ACE inhibitor was the most effective adjunctive therapy in this mesenteric ischemia model. There was no evidence that an inotropic effect, rather than SMA vasodilation, was the responsible mechanism of action.