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Biomedical subjects

L W Traverso

Publications and source records attributed to L W Traverso.

At least 109 records · Page 6Linked to original sources
PubMed1985

Effectiveness of aprotinin in blocking a hypotensive factor of pancreatic origin from the pig, dog and monkey.

Minced pancreas or a collagenase solution alone had no effect on blood pressure when infused into experimental animals. However, collagenase digested fragments or the digested pancreatic supernatant (PSF) produces profound hypotension. Previously we have shown that aprotinin, a proteolytic enzyme inhibitor, successfully blocked PSF-induced hypotension in the pig but did not alter this hypotension in the dog or monkey. Species variability of aprotinin blockade was further investigated by infusing PSF from either the pig, dog, or monkey into five animals of the other two species ("across species"). PSF alone produced hypotension in every animal "across species" but PSF "across species" and in combination with aprotinin did not produce a hypotensive reaction in each "across species" combination. These species differences of the aprotinin blockade should be considered when seeking reasons why aprotinin has not proven effective in preventing the morbidity and mortality of human pancreatitis.

Animals↗
PubMed1985

Naloxone does not prevent death after rapid hemorrhage in swine.

Despite the array of hemorrhage models, animal species and experimental designs, it seems clear that naloxone with or without volume replacement has no place in the treatment of rapidly exsanguinating traumatized patients. In this situation, the adrenergic hemodynamic effects, indirectly due to naloxone, further decrease tissue perfusion leading to a deleterious outcome. We suggest that the membrane stabilizing effects rather than the hemodynamic effects of naloxone should be pursued in the treatment of low perfusion states with longer survival times than rapid hemorrhage, such as septic and cardiogenic shock.

Animals↗
PubMed1985

Military antishock trousers prolong survival after otherwise fatal hemorrhage in pigs.

Military antishock trousers (MAST) have not received universal acceptance for use during hypovolemia because cardiac output results have been conflicting, lower extremity compartment syndromes have been reported, and a prospective clinical trial has not been performed. We completed survival studies in a fatal porcine hemorrhage model which simulates human exsanguination. Trousers were specifically made for the weight of the swine in this study and then were calibrated by observing transmitted pressure to the lower abdomen and upper hind limbs. When the trousers were inflated to 60 torr, 77% of the inflation pressure was transmitted to the proximal lower leg (46 +/- 8 torr) and 58% was monitored in the lower abdomen (35 +/- 4 torr). Compared to a noninflation control group, we found the survival time significantly prolonged after an otherwise fatal hemorrhage. The mechanism appears to be through increased tissue perfusion probably not related to a transient translocation of lower extremity blood volume.

Abdomen↗
PubMed1984

Morphological changes in pancreatic fragments prepared for transplantation by collagenase treatment.

Canine pancreases were excised, minced, mechanically chopped, and incubated with collagenase in a manner similar to that used routinely in the preparation of mixed-cell pancreatic autografts. The resultant pancreatic fragments were studied by light and electron microscopy after various periods of collagenase incubation. As a control, pancreatic tissue was studied immediately after organ excision, immediately before addition of collagenase, and after various periods of incubation in balanced salt solution without collagenase. The mincing and chopping procedures alone induced a large population of highly aberrant, severely vacuolated acinar cells within the fragments. This vacuolation was caused by massive dilation of the cisternae of the rough endoplasmic reticulum. Subsequent incubation in collagenase solution, which appeared to destroy the aberrant cells in a selective manner, led to a remnant population with much improved acinar cell morphology. Incubation in balanced salt solution without collagenase resulted in a progressive increase in vacuolated cell incidence until abnormal pancreatic acinar cells dominated the tissue. The findings suggest that collagenase treatment may facilitate mixed-cell pancreatic transplantation by culling degenerative acinar cells from the grafted cell population, thereby reducing the likelihood of autodigestion at the transplant site. The extensive acinar cell destruction mediated by the collagenase may also be responsible for the release of a previously described hypotensive factor (pancreatic shock factor) into the graft infusion.

Animals↗
PubMed1984

Bleeding esophageal varices and portal vein thrombosis after pancreatic mixed-cell autotransplantation.

A patient with chronic pancreatitis caused by congenital pancreatic duct atresia underwent total pancreatectomy and mixed-cell pancreatic autotransplantation by portal vein embolization. Two years later she developed massive upper gastrointestinal bleeding from gastroesophageal varices and required a mesocaval H graft. The cause of the portal hypertension was portal vein thrombosis caused by portal vein infusion of pancreatic homogenate, and it represents a serious complication of the procedure. Although this is the second report of portal hypertension that required portasystemic shunting after islet cell autotransplantation, it is the first reported case of the development of bleeding esophageal varices caused by portal vein thrombosis after pancreatic islet cell transplantation.

Adult↗
PubMed1984

A clinically applicable exsanguination shock model in swine.

In order to evaluate treatments of the rapid exsanguination seen in the majority of civilian trauma or combat fatalities, we designed a rapid exsanguination, conscious, unheparinized 100% fatal porcine hemorrhage model. Immature female swine were bled 60% of their estimated blood volume 5 days after placement of a bleeding catheter. The change in arterial base excess concentration (BE) and hematocrit (Hct) was followed after hemorrhage. Variables were bleeding time (120, 60, 30, and 15 min) and catheter placement (carotid, 7 cases; and distal aorta, 24 cases). The Hcts before hemorrhage were similar in both groups. The time for removal of 60% EBV for routine mortality was longer with the carotid (60 min) versus the distal aorta (15 min) catheter group. At autopsy the carotid catheters partially obstructed the orifice of the opposite carotid. In the aortic group, a rate of hemorrhage of 2.65 +/- 0.97 ml/kg/min was required to provide the ischemia necessary for 100% mortality. The BE after hemorrhage was significantly different in survivors versus nonsurvivors. A carotid artery catheter that extends into the porcine brachiocephalic artery appears to cause artifactual mortality by interfering with blood flow to the opposite carotid. A conscious, unheparinized, and reliably fatal exsanguination model has been standardized. The animal must sustain a 60% EBV loss from the distal aorta in 15 min.

Animals↗
PubMed1983

Hemodynamic characterization of porcine hemorrhagic pancreatitis ascites fluid.

The hemodynamic reactions of hemorrhagic pancreatitis ascites fluid (HAF) were observed after intravascular injection in the pig. The HAF vascular reactions were compared to the reactions of known vasoactive agents in hopes of identifying the vasoactive agent(s) in HAF. Pancreatitis was induced in five pigs with pancreatic ductal injection of a bile/trypsin mixture. HAF from these pigs was injected into the portal vein of five anesthetized pigs which were monitored for changes in femoral artery pressure (FAP), cardiac output (CO), and portal pressure (PoVP). Trypsin was also tested in the same way in five additional pigs. HAF elevated PoVP, then lowered VAP, depressed CO, and exhibited tachyphylaxis. Trypsin did not cause tachyphylaxis. The effects observed after infusion of HAF are similar to the reported effects observed after injecting histamine, an agent previously implicated in hemorrhagic pancreatitis.

Acute Disease↗
PubMed1982

Hemodynamic measurements after administration of aprotinin and/or heparin during pancreatic cell autotransplantation in the dog, pig, and monkey.

Transient shock in the form of systemic hypotension and portal venous hypertension has accompanied the portal vein infusion of pancreatic mixed cell autografts in human and canine recipients. The use of aprotinin and/or heparin has been suggested as blocking agents for this vascular reaction. The supernatant from the collagenase-digested pancreatic cells contains the pancreatic shock factor (PSF). A total of 45 animals were studied: 15 mongrel dogs, 15 domestic pigs, and 15 Rhesus monkeys. Femoral artery pressure (FAP), portal venous pressure (PoVP), and cardiac output were recorded continuously. Each animal received 0.05 ml/kg of autologous PSF intravascularly. Each animal species was then divided into three study areas containing five animals with Study 1 receiving PSF plus increasing doses of aprotinin (2,500, 5,000 and 10,000 KIU/kg); Study 2, full heparinization and then PSF; and Study 3, full heparinization and then PSF plus aprotinin. The same vascular hemodynamic factors were measured. Aprotinin blocked the entire shock reaction in the pig (FAP and PoVP), only partially blocked the PoVP elevation in the dog, and blocked neither FAP nor PoVP changes in the monkey. Heparinization did not change the shock reaction in any animal species nor did it change the response to aprotinin blockade in any species. A species response variability exists between the dog, pig, and monkey when aprotinin is injected to block PSF obtained from the animal's own pancreas. If the primate and human responses to aprotinin blockade are similar, aprotinin and/or heparin should not prevent the transient shock associated with human pancreatic mixed cell autotransplantation.

Animals↗
PubMed1981

The Whipple procedure and other standard operative approaches to pancreatic cancer.

In a series of 50 patients with cancer of the pancreas who wee undergoing resection of the pancreatic head and the duodenum, the average survival was 16.2 months. If the resected margin was free of tumor the average survival was 20.3 months. In 103 less favourable cases treated by biliary bypass, with or without gastroenterostomy, the average survival was only 6.2 months. Although these series are not comparable, pancreaticoduodenal resection for cancer of the pancreas and periampullary area has been utilized in cases without distant metastases in an effort to extend the period of palliation and to achieve occasional long-term survival. Currently available diagnostic techniques may permit earlier diagnosis and improved results. A positive tissue diagnosis is not essential before proceeding with resection, but this aspect of the operation should be fully discussed with the patient. An unfavorable condition of the residual pancreas for anastomosis, or a positive frozen section examination of the pancreas at the line of transection may indicate total pancreatectomy, but complete resection is not used routinely. The incidence of jejunal ulceration, a serious late postoperative complication, may be reduced by utilizing a 60-70% gastric resection or antrectomy and vagotomy.

Biliary Tract Surgical Procedures↗
PubMed1981

Is hepatic portal venous gas an indication for exploratory laparotomy?

Three patients with roentgenographic evidence of hepatic portal venous gas (HPVG) were hospitalized within a one-month period at one hospital. The abdominal roentgenograms were obtained because the clinical signs of abdominal rigidity, distention, or both were present. Each patient had exploratory laparotomy after the HPVG was seen. During the operations, extensive cyanotic/necrotic bowel was found. The patients died within a few hours after the procedures. These cases bring the total to 67 cases in the retrievable literature. One quarter of the patients described have survived; none of them had extensive bowel necrosis associated with their HPVG. In order to determine the extent of bowel necrosis associated with HPVG, and to determine if treatment is possible, an exploratory laparotomy should be performed.

Female↗
PubMed1981

Human pancreatic cell autotransplantation following total pancreatectomy.

During total pancreaticoduodenectomy for chronic pancreatitis, four patients received an intraportal pancreatic mixed-cell autograft prepared by collagenase digestion. The technique of this autotransplantation procedure was successfully developed using a normal canine pancreas, but has proved difficult to apply in the human chronic pancreatitis model. Our four patients became insulin-dependent, with proof of intrahepatic insulin production in only one patient. Three factors have contributed to the lack of graft success: 1) the preoperative endocrine status, 2) systemic hypotension and portal hypertension secondary to graft infusion, and 3) difficulty applying the successful technique in a normal dog pancreas to an extensively scarred human pancreas. The preoperative insulin response during a glucose tolerance test was blunted or delayed in the three patients tested. An immediate decrease in blood pressure and rise in portal pressure occurred in every patient and prevented infusion of the entire graft (30-50%) in three patients. Unfortunately, the patient with the most compromised insulin status was the only patient able to receive the entire graft. Our experience would indicate that further refinements in technique are necessary to prevent the vascular reaction and allow infusion of the entire graft. Furthermore, normal islet cell function is necessary before a successful graft can be expected.

Adolescent↗
PubMed1980

Efficacy of the gallbladder for drainage in biliary obstruction: a comparison of malignant and benign disease.

To evaluate the efficacy of the gallbladder as an alternate drainage route in biliary obstruction, we reviewed the charts of 79 patients who underwent 80 cholecystoenterostomy (CCE) procedures at the UCLA Hospital during the period between 1955 and 1978. Among these procedures, 62 (77.5%) were done for malignant obstruction and 18 (22.5%) for benign obstruction; three patients with malignancy and one with benign disease were unavailable for follow-up. The CCE procedure failed in nine patients (11.8), five of 59 cases involving malignancy (8.5%), and four of 17 (23.5%) for benign disease. The 26-month cumulative patency was found to be 78.9% in malignant disease and 68.6% in benign disease. The combined failure rate of cholecystojejunostomy was 8.3%, compared to 30.8% with cholecystoduodenostomy. "Gross inflammation" was the only variable predictive of future CCE failure. The study suggests that CCE should be used primarily in terminal malignancy when a simple, short-term biliary bypass is desired.

Adenocarcinoma↗
PubMed1980

Atrophic coarctation of the abdominal aorta.

Two cases illustrate the clinical manifestations and angiographic findings associated with segmental stenosis of the abdominal aorta. Such lesions represent the chronic occlusive stage of Takayasu's disease, a nonspecific inflammatory arteritis of uncertain etiology. While the disease is considered autoimmune, an infectious process may be involved. Complications typically associated with stenotic lesions of the abdominal aorta are secondary renal hypertension and ischemic symptoms secondary to vascular insufficiency. Surgical correction, the treatment of choice, has achieved excellent results for these well-localized lesions. Secondary renal hypertension was relieved by a spenorenal shunt and the disease has since been controlled with conservative management in the first patient. An aortofemoral bypass graft successfully alleviated the vascular insufficiency in the second patient, although the patient unfortunately expired from a refractory postoperative cardiac complication.

Adolescent↗
PubMed1980

Preservation of the pylorus in pancreaticoduodenectomy a follow-up evaluation.

We have previously reported our efforts to minimize postgastrectomy symptoms in two patients with benign disease who underwent resection of the head of the pancreas and the duodenum. In these cases the pylorus and first portion of the duodenum were preserved during pancreaticoduodenectomy. Our experience has now been extended to encompass 18 patients, eight of whom were available for comprehensive evaluation an average of six months postoperation. These studies have attempted to differentiate malabsorption of pancreatic insufficiency from possible gastrointestinal dysfunction of the new alimentary connection. Pancreatic insufficiency was evaluated by a 72-hour stool collection and radioactive trioctanoate (RATO) test. Gastrointestinal absorption was evaluated by D-xylose excretion and the Schilling test, as well as serum vitamin. A, vitamin B-12, carotene, folate, iron, and total iron binding capacity. Gastrointestinal secretion and motility were assessed by using pyloric fluoroscopy, gastric barium emptying, the Hunt test, and gastric acid analysis. Finally, a questionnaire regarding clinical symptoms of postgastrectomy syndromes and malabsorption was answered. Although every patient exhibited marked pancreatic insufficiency by laboratory tests, 88% described normal formed bowel movements, and weight loss was claimed by only 25%. Other test findings were generally normal. While the follow-up period has been limited to three years, the current data demonstrate that gastrointestinal function subsequent to preservation of the pylorus has not thus far predisposed to postgastrectomy syndromes or marginal ulcers. All of the patients required intensive pancreatic enzyme replacement.

Adolescent↗