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Biomedical subjects

J L Cameron

Publications and source records attributed to J L Cameron.

At least 217 records · Page 12Linked to original sources
PubMed1988

Complications of acute diverticulitis of the colon: improved early diagnosis with computerized tomography.

We have evaluated the diagnostic role of computerized tomography in 42 patients suspected clinically of having a complication of acute diverticulitis (abscess, colovesical fistula, or both). Diverticular abscesses were confirmed at operation in 10 patients. All 10 patients were diagnosed preoperatively on computerized tomography by the triad of diverticula, a segmentally thickened colon, and extravisceral fluid collection with (6 patients) or without (4 patients) associated gas. Contrast enema study suggested the presence of a diverticular abscess in only two of eight patients studied. Colovesical fistulas were confirmed in 12 patients. Eleven of 12 were diagnosed preoperatively on computerized tomography by the triad of air in the bladder, thickened colon adjacent to an area of thickened bladder, and the presence of colonic diverticula. Contrast enema examinations demonstrated the fistula in only three of eight patients studied. The remaining 20 patients proved to have uncomplicated acute diverticulitis. Findings on computerized tomography included the presence of a segmentally thickened colon with diverticula but without the findings of an abscess or a colovesical fistula. Computerized tomography correctly visualized acute diverticular complications in 21 of 22 patients and it excluded an abscess or fistula in all 20 patients with uncomplicated acute diverticulitis who were suspected of having a diverticular complication. Computerized tomography is the most sensitive and specific test for diagnosing complications of acute diverticulitis. It should be an early consideration in patients with suspected diverticular abscesses or fistulas so that appropriate therapy is not delayed.

Abscess↗
PubMed1988

Topical antibiotics in the high-risk biliary surgical patient. A prospective, randomized study.

This randomized, prospective study has evaluated the efficacy of topical antibiotics in preventing infective complications in patients undergoing high-risk biliary surgery. Sixty-nine patients who underwent bile duct exploration, choledochoenteric anastomosis, or cholecystectomy, either for acute cholecystitis or because they were older than 65 years of age, were randomized to the following three groups: Group I, topical antibiotics alone (22 patients); Group II, cefoxitin and topical antibiotics (24 patients); and Group III, penicillin, tobramycin, clindamycin, and topical antibiotics (23 patients). The incidence of infective complications was no different among the groups. There was one wound infection in each group, one episode of bacteremia in Group II, and no intraabdominal abscesses. This study has demonstrated that parenteral antibiotics administered prophylactically in the perioperative period offer no additional benefit over the use of effective topical antibiotics used intraoperatively in patients undergoing high-risk biliary surgery.

Aged↗
PubMed1988

Prevalence and characteristics of Barrett esophagus in patients with adenocarcinoma of the esophagus or esophagogastric junction.

The prevalence and characteristics of Barrett esophagus in patients with adenocarcinoma of the esophagus or esophagogastric junction are uncertain. We studied 61 consecutive esophagogastrectomy specimens with adenocarcinoma, which were subjected to extensive histopathologic examination. Barrett esophagus was found in 64% of the cases (39 of 61), but had been recognized in only 38% of the patients with Barrett-associated carcinoma who had undergone preoperative endoscopy with biopsy (13 of 34). The median extent of Barrett esophagus with adenocarcinoma was 5 cm (range, 1 cm to 12 cm), and distinctive-type ("specialized") Barrett mucosa predominated (35 of 39; 90%). The Barrett adenocarcinomas were centered in the distal esophagus 2 cm +/- 0.3 cm above the esophagogastric junction. The patients with Barrett adenocarcinoma showed a striking predominance of white men (34 of 39; 87%) in contrast to gastric adenocarcinoma cases (21 of 69; 30%) and to Barrett patients without carcinoma or dysplasia (75 of 149; 50%), but similar to patients having adenocarcinoma of the esophagus or esophagogastric junction without demonstrable Barrett esophagus (16 of 22; 73%). Our findings suggest that most adenocarcinomas of the esophagus or esophagogastric junction are Barrett carcinomas, rather than gastric cardiac cancers or other types of esophageal adenocarcinoma; most Barrett adenocarcinomas occur in short segments of Barrett esophagus, which may be difficult to detect at endoscopy; and white men with Barrett esophagus may constitute a clinically identifiable at-risk group suitable for surveillance.

Adenocarcinoma↗
PubMed1988

Resection of hepatic duct bifurcation and transhepatic stenting for sclerosing cholangitis.

Thirty-one patients with sclerosing cholangitis underwent reconstruction of their hepatic duct bifurcation and long-term stenting between 1980 and 1987. Indications for surgery were persistent jaundice in 29 and recurrent cholangitis in two. The mean serum bilirubin level before surgery was 10.4 mg/dl. Liver biopsy revealed that 26 patients had varying degrees of hepatic fibrosis, and five patients had progressed to secondary biliary cirrhosis. In 29 patients the major obstructive duct disease was at or near the hepatic duct bifurcation, and in two patients it was in the distal common duct. The operative procedure consisted of: (1) excision of the hepatic duct bifurcation and extrahepatic biliary tree, (2) dilatation of the intrahepatic ducts, (3) insertion of Silastic transhepatic biliary stents, and (4) bilateral hepaticojejunostomies. Two of the five patients (40%) with cirrhosis died after surgery. In contrast, only one of 26 patients (3.9%) with hepatic fibrosis died after operation. The 1-, 3-, and 5-year actuarial survival rates for patients with cirrhosis were 20%, 20%, and 20%, respectively. The only long-term survivor underwent a liver transplant. The 1-, 3-, and 5-year actuarial survival rates for patients with hepatic fibrosis were 92%, 87%, and 71%, respectively. In addition, the mean serum bilirubin levels of patients with hepatic fibrosis at 1, 2, 3, 4, and 5 years were 3.4 mg/dl, 2.9 mg/dl, 4.0 mg/dl, 5.4 mg/dl, and 4.3 mg/dl, respectively. Two of the long-term survivors subsequently underwent a liver transplant. Patients with sclerosing cholangitis, persistent jaundice, and biliary cirrhosis should be referred for consideration of liver transplantation. However, in the absence of biliary cirrhosis, if the major obstructive disease is at the hepatic duct bifurcation, primary biliary reconstruction and long-term stenting should be considered.

Adult↗
PubMed1988

Phosphorus-31 nuclear magnetic resonance spectroscopic study of the canine pancreas: applications to acute alcoholic pancreatitis.

The first nuclear magnetic resonance spectroscopic study of the canine pancreas is described. Both in-vivo, ex-vivo protocols and nmr observables are discussed. The stability of the ex-vivo preparation based on the nmr observables is established for at least four hours. The spectra obtained from the in-vivo and ex-vivo preparations exhibited similar metabolite ratios, further validating the model. Metabolite levels were unchanged by a 50% increase in perfusion rate. Only trace amounts of phosphocreatine were observed either in the intact gland or in extracts. Acute alcoholic pancreatitis was mimicked by free fatty acid infusion. Injury resulted in hyperamylasemia, edema (weight gain), increased hematocrit and perfusion pressure, and depressed levels of high energy phosphates.

Alcoholism↗
PubMed1988

Sclerosing cholangitis.

PSC is an unusual disease of unknown etiology. In fact, sclerosis of the bile ducts may be the result of multiple factors, including autoimmune, bacterial, congenital, drug, or viral agents. The most commonly associated diseases are ulcerative colitis and chronic pancreatitis. Except for the earliest stages of the disease, liver histology is not specific. Most patients present with jaundice, pain, and pruritus, although an increasing number of asymptomatic patients with inflammatory bowel disease and abnormal liver function are being diagnosed. Cholangiography is the key to the diagnosis and is usually pathognomonic except in the unusual case where PSC is confused with cholangiocarcinoma. Multiple forms of medical therapy have been tried, including steroids, azothiaprine, D-penicillamine, colchicine, cholestyramine, and antibiotics. To date, however, none of these medications has altered the course of this disease. In recent years, balloon dilation of biliary strictures has been accomplished via endoscopic and percutaneous transhepatic approaches. However, in patients with PSC these nonoperative manipulations must be done repeatedly, may require multiple general anesthetics, and are difficult to perform. A direct surgical approach to the biliary tree with prolonged transhepatic stenting is indicated in patients with severe hilar or extrahepatic stricturing, persistent jaundice and/or recurrent cholangitis, and no evidence of cirrhosis. Hepatic transplantation should be reserved for patients with PSC who have well-established cirrhosis and in whom other therapeutic options have failed.

Bile Ducts↗
PubMed1988

Acute diverticulitis of the cecum and ascending colon diagnosed by computed tomography.

Between June 1984 and August 1985, computed tomography (CT) was performed upon seven patients with diverticulitis of the cecum and ascending colon who presented with acute right lower quadrant symptoms of unknown origin. Three of these patients had undergone an appendectomy, while in the remaining four patients, the history and physical findings were atypical of acute appendicitis. CT findings suggestive of acute diverticulitis including thickening of the intestinal wall and pericolonic inflammation were present in all seven patients. In four patients, the colonic inflammation was limited to the segment of ascending colon superior to the ileocecal valve. In one patient, the inflammation involved both the ascending colon and the cecum, while in the two remaining patients, the inflammatory changes were limited to the cecum. An associated diverticular abscess was present in five patients and all were correctly identified preoperatively by CT. One patient in whom the diagnosis of uncomplicated diverticulitis of the ascending colon was made on the basis of the CT scan, was successfully managed nonoperatively with antibiotics. Five patients required a right hemicolectomy for perforated diverticulitis with abscess. The remaining patient underwent a right hemicolectomy for recurrent episodes of acute diverticulitis. Our experience suggests that CT is useful in the early diagnosis of diverticulitis of the cecum and ascending colon.

Acute Disease↗
PubMed1988

Mesoatrial shunt hemodynamics.

Hemodynamic profiles were obtained for patients with portal hypertension secondary to the Budd-Chiari syndrome who underwent mesoatrial shunting procedures. In contrast to the well-known hyperdynamic, low-resistance state of chronic cirrhosis, patients with the Budd-Chiari syndrome had normal cardiac index and systemic vascular resistance values before anesthesia and surgery. Opening the mesoatrial shunt produced a 46% (p less than 0.01) increase in cardiac index and a 38% (p less than 0.01) decrease in overall systemic vascular resistance. Right atrial pressure and pulmonary capillary wedge pressures were sharply increased--by 5.3 mm Hg and 4.7 mm Hg, respectively (p less than 0.01). A mathematical model was developed to assess the cause of the observed changes in systemic vascular resistance. The model suggests that the hemodynamic changes seen with shunt opening are unlikely to be the result of shunt effects alone and that dilatation of peripheral vascular beds is probable. Thus shunting converts the normal systemic vascular resistance and cardiac index of patients with the Budd-Chiari syndrome to the high-output, low-resistance state seen in patients with chronic cirrhosis. Although the physiology is complex, we conclude that the data are consistent with release, by the shunting process, of a systemic vasodilator.

Adult↗
PubMed1987

Closed-suction versus Penrose drainage after cholecystectomy. A prospective, randomized evaluation.

Closed-suction drainage was compared prospectively to open, passive drainage (Penrose drains) in 128 patients undergoing cholecystectomy. Patients were randomized at the time of operation to receive either closed-suction drains (Group I, 67 patients) or Penrose drains (Group II, 61 patients). The preoperative clinical parameters of the two groups were similar. The patients in Group I when compared with those in Group II had a shorter duration of drainage (3.3 days and 4.1 days, respectively, p less than 0.01), a lesser volume of drainage in the first 48 hours postoperatively (78 ml and 132 ml, respectively, p less than 0.001), a decreased incidence of fever on the night of operation (24 of 67 patients and 39 of 61 patients, respectively, p less than 0.05) and on the first postoperative day (26 of 67 patients and 32 of 61 patients, respectively, p less than 0.05), and a lower leukocyte count on the first postoperative day (12,000 cells/mm3 and 14,100 cells/mm3, respectively, 0.05 less than p less than 0.1). Patients in Group I tended to have a lower rate of wound infection (1 of 67 patients versus 5 of 61 patients in Group II, 0.05 less than p less than 0.1) and had a much lower incidence of drain site tenderness (8 of 67 patients in Group I versus 24 of 61 patients in Group II, p less than 0.05). This study demonstrates the superiority of closed-suction drains over open, passive drains after cholecystectomy.

Cholecystectomy↗
PubMed1987

Improved hospital morbidity, mortality, and survival after the Whipple procedure.

Between 1969 and 1986, 88 patients had a Whipple resection for adenocarcinoma of the pancreas (N = 50), ampulla (N = 19), distal bile duct (N = 10), and duodenum (N = 9). Forty-nine patients were men, 39 were women, and the mean age was 58 years (range: 34-84 years). The patients were divided into two groups on the basis of two different time periods: those operated on from 1969 to 1980 (N = 41) and those operated on from 1981 to 1986 (N = 47). There were no significant differences between the two groups in terms of mean age, sex distribution, duration of symptoms before presentation, or mean weight loss. Likewise, preoperative laboratory data were similar for both groups of patients. In addition, mean tumor size for patients with pancreatic cancer (3.5 cm vs. 3.2 cm) and patients with nonpancreatic periampullary cancer (1.9 cm vs. 2.2 cm) was similar in both groups, as was the incidence of positive lymph nodes. Among the 41 patients operated on during the first period, hospital morbidity and mortality rates were 59% and 24%, respectively. In contrast, hospital morbidity and mortality rates were 36% and 2%, respectively, among the 47 patients operated on during the recent period. During the recent period, more Whipple procedures were performed each year (7.8 vs. 3.4) and by fewer surgeons (3.4 operations/surgeon vs. 1.9 operations/surgeon). In addition, between 1981 and 1986, there were fewer total pancreatectomies (9% vs. 39%), fewer vagotomies (26% vs. 76%), and more pyloric-preserving procedures (30% vs. 0) performed compared with the earlier period. During the recent period, mean operative time (7.8 vs. 9.0 hours), mean estimated blood loss (1694 vs. 3271 mL), and mean intraoperative blood replacement (3.6 vs. 6.3 units) were all significantly less than in the earlier period. These findings suggest that the recent decline in operative morbidity and mortality may be due to fewer surgeons performing more Whipple resections in less time and with less blood loss. The actuarial 5-year survival rate for the 38 patients with nonpancreatic periampullary cancer was 34%. Surprisingly, the actuarial 5-year survival rate among the 50 patients with pancreatic cancer was 18%. Moreover, in the absence of positive lymph node involvement, the 5-year actuarial survival rate among patients with pancreatic cancer was 48%. No explanation is obvious for the improvement in survival among patients with pancreatic cancer.

Adenocarcinoma↗
PubMed1987

Mesoatrial shunts for Budd-Chiari syndrome and inferior vena cava thrombosis: angiographic and hemodynamic evaluations.

When inferior vena caval obstruction complicates the Budd-Chiari syndrome, conventional portosystemic shunts are not possible. The mesoatrial shunt has been devised to enable portal and sinusoidal decompression in these patients. Findings in 12 patients with Budd-Chiari syndrome and inferior vena caval obstruction in whom a mesoatrial shunt was performed are reported. Preoperative inferior vena cavography with pressure measurements is essential to determine the appropriate shunt procedure. Postoperatively, shunt patency is assessed with superior mesenteric arterial portography. Where possible, transvenous catheterization of the shunt is performed to confirm patency and assess hemodynamic function.

Adult↗
PubMed1987

Diverticulitis of the right colon: CT observations.

Recent reports on the CT evaluation of patients with diverticulitis of the left colon prompted a retrospective review of the CT findings in six patients with diverticulitis of the cecum and ascending colon. All had pain and tenderness in the right lower quadrant. In each case, CT findings showed regional thickening of the colonic wall, an extraluminal mass involving the cecum and/or ascending colon, haziness and linear strands in adjacent pericolic fat, and thickening of nearby fascial planes. Extraluminal air was noted in four patients, and contrast-filled structures suggesting diverticula were present within the inflammatory masses of two. These results suggest that CT is a useful imaging tool in the diagnosis of right-sided diverticulitis.

Adult↗
PubMed1987

The value of preoperatively placed percutaneous biliary catheters in reconstruction of the proximal part of the biliary tract.

Between May 1982 and January 1986, 55 patients with strictures of the proximal part of the biliary tract have been reconstructed with Silastic (silicone rubber) transhepatic biliary stents after the preoperative percutaneous placement of Ring catheters into one or both of the hepatic ducts. Twenty-five patients had tumors of the proximal portion of the biliary tract, 19 had sclerosing cholangitis and the remaining 11 had benign strictures of the biliary tract. Ring catheters were placed into both the right and left hepatic ducts in 38 of the 55 patients. In the remaining 17 patients, a single Ring catheter was advanced beyond the stricture and into the duodenum in 50 of the 55 patients. The preoperative percutaneous placement of Ring catheters into the right and left hepatic ducts has proved to be a useful technical aide in the operative management of patients with lesions of the proximal part of the biliary tract. Having these catheters in place at the time of the operation helps significantly in dissecting the extrahepatic biliary tree and bifurcation and are subsequently used to place the transhepatic Silastic stents that are used in the reconstruction of the biliary tract.

Biliary Tract Diseases↗
PubMed1987

Enterovesical fistula.

During a period of 18 months, 24 patients were identified with enterovesical fistulas. The fistulas were colovesical in 18, ileovesical in four and rectovesical and appendicovesical in one each. Fifteen of the 23 patients in whom this information was available had pneumaturia and four had fecaluria. The standard battery of diagnostic tests for enterovesical fistulas was performed. Thirteen patients with colovesical fistulas had small intestinal series; the fistula was demonstrated in only five patients. Sixteen patients had an intravenous pyelogram and the fistula was demonstrated in none. Cystoscopy was performed upon 15 patients and the fistula was demonstrated in one. A cystogram was performed upon ten patients and the fistula was demonstrated in four. In contrast, all patients had positive computed tomographic findings. The pathognomonic finding of air within the bladder was demonstrated in 20 of 23 patients without recent transurethral instrumentation. All 24 computed tomographic scans demonstrated an abnormally thickened segment of intestine in intimate contact with a thickened bladder wall at the site of the fistula. This was associated with a paravesical mass in 23 of the patients. Two of the four patients in whom bladder air was not seen had a vesical fistula of the small intestine. All 24 fistulas were confirmed by operation (22 patients) or subsequent clinical course (two patients). These findings suggest that computed tomography is the most accurate diagnostic tool available for demonstrating enterovesical fistulas. Computed tomography should supplant the use of other less sensitive diagnostic test currently included in the evaluation of patients with a suspected enterovesical fistula.

Colonic Diseases↗
PubMed1987

The role of leukocytes in the production of oxygen-derived free radicals in acute experimental pancreatitis.

Oxygen-derived free radicals mediate an important step in the initiation of experimental acute pancreatitis in the ex vivo perfused canine pancreas model. In other organ systems, circulating leukocytes may serve as one source of oxygen-derived free radical production. The current experiments were designed to evaluate the role of circulating leukocytes in the generation of injury in this model. Four experimental groups of animals were studied: group I consisted of controls (n = 6); group II had white blood cell (WBC) depletion (n = 4) in which the recirculating whole blood perfusate was depleted of 98% of its circulating leukocytes; group III had oleic acid infusion (FFA) alone (n = 9), which induced pancreatitis; group IV had WBC depletion and FFA (n = 6), in which oleic acid was infused after depletion of the circulating leukocytes in the perfusate. During the 4-hour perfusion period, the pancreatic preparations were monitored hourly for the development of edema, weight gain, and release of alpha-amylase into the perfusate. Animals in groups I and group II manifested no gross edema, gained minimal weight, and did not manifest hyperamylasemia. Leukocyte depletion alone had no effect. In group IV animals marked edema, significant weight gain, and hyperamylasemia developed to the same extent as in group III animals. These results demonstrate that circulating leukocytes are not essential to the development of pancreatitis in this model and suggest that another source of oxygen-derived free radicals mediates this injury.

Acute Disease↗
PubMed1987

Temporal efficacy of allopurinol during the induction of pancreatitis in the ex vivo perfused canine pancreas.

Oxygen-derived free radicals play an important role in the pathogenesis of experimental acute pancreatitis in the isolated perfused canine pancreas. We have previously found that pretreatment with allopurinol inhibits xanthine oxidase--apparently the primary source of free radical generation in this model--and prevents the initial development of pancreatitis. In these experiments, we evaluated whether allopurinol administered after the onset of pancreatitis would arrest the progression of the disease process. Edema formation, weight gain, and the release of amylase activity into the perfusate in the ex vivo perfused canine pancreas model were monitored during a 4-hour perfusion period. There were six experimental groups: Group I (control) received no treatment, group II (allopurinol alone) received only allopurinol (100 mg) at the start of perfusion, and groups III through VI were each given an infusion of 0.3 ml of oleic acid (FFA) over a 1-hour period to initiate acute pancreatitis. Group III (FFA alone) received no other treatment. In group IV (pretreatment with allopurinol), group V (concurrent treatment with allopurinol), and group VI (posttreatment with allopurinol), allopurinol (100 mg) was administered 1 hour before, concurrent with, or at the end of the FFA infusion, respectively. Pretreatment with allopurinol prevented edema formation, markedly attenuated weight gain, and the release of amylase caused by the FFA infusion. Administration of allopurinol concurrent with the FFA infusion provided only partial protection, whereas posttreatment with allopurinol failed to arrest the progression of the injury process. Therefore, the use of allopurinol to inhibit oxygen-derived free radical production from xanthine oxidase prevented the development of acute pancreatitis in this model; however, treatment with allopurinol after initiation of the disease process failed to arrest the progression of acute pancreatitis.

Allopurinol↗