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Biomedical subjects

C H Scudamore

Publications and source records attributed to C H Scudamore.

At least 37 records · Page 2Linked to original sources
PubMed1998

Radiofrequency ablation of porcine liver in vivo: effects of blood flow and treatment time on lesion size.

OBJECTIVE: To determine, in vivo, the effect of radiofrequency ablation (RFA) treatment time and tissue blood flow on the size and shape of the resulting necrotic lesion in porcine liver. SUMMARY BACKGROUND DATA: Radiofrequency ablation is an electrosurgical technique that uses a high frequency alternating current to heat tissues to the point of desiccation (thermal coagulation). Radiofrequency ablation is well established as the treatment of choice for many symptomatic cardiac arrhythmias because of its ability to create localized necrotic lesions in the cardiac conducting system. Until recently, a major limitation of RFA was the small lesion size created by this technique. Development of bipolar and multiple-electrode RFA probes has enabled the creation of larger lesions and therefore has expanded the potential clinical applications of RFA, which includes the treatment of liver tumors. A basic understanding of factors that influence RFA lesion size in vivo is critical to the success of this treatment modality. The optimal RFA technique, which maximizes liver lesion size, has yet to be determined. Theoretically, lesion size varies directly with time of application of the RF current, and inversely with blood flow, but these relationships have not been previously studied in the liver. METHODS: Six animals underwent hepatic RFA (460 kHz), for 5, 7.5, 10, 12.5, 15, and 20 minutes. Identical, predetermined anatomic areas of the liver were ablated in each animal. Two additional animals underwent 12 RFA treatments -- 6 with vascular inflow occlusion (Pringle maneuver) and 6 with uninterrupted hepatic blood flow. Animals were euthanized and the livers were removed for gross pathologic examination. All lesions were measured in three dimensions and photographed. Tissues were examined by routine histology and by histochemistry to determine viability. RESULTS: Increasing duration of RFA application from 5 through 20 minutes did not create lesions of larger diameter, but this time increase did predict deeper lesion production (beta = 0.34, p = 0.04). A range of lesion shapes were created from four separate ovals (corresponding to each electrode), to larger ovals intersecting to form a cross, to spheroid lesions. The number of blood vessels in close proximity to the probe tip (within a 1-cm radius from the center of the lesion) strongly predicted minimum lesion diameter (beta = -0.61, p = 0.0001) and lesion volume (beta = -0.56, p = 0.0004). This negative effect of blood flow on lesion size was confirmed experimentally. Radiofrequency ablation lesions created during a Pringle maneuver were significantly larger in all three dimensions than lesions created without a Pringle maneuver: minimum diameter was 3.0 cm (with Pringle) versus 1.2 cm (p = 0.002), maximum diameter was 4.5 cm (with Pringle) versus 3.1 cm (p = 0.002), depth was 4.8 cm (with Pringle) versus 3.1 cm (p < 0.001), and lesion volume was 35.0 cm3 (with Pringle) versus 6.5 cm3 (p < 0.001). CONCLUSIONS: Blood flow is a strong predictor of all RFA lesion dimensions in porcine liver in vivo, whereas a change of treatment time from 5 to 20 minutes is predictive only of lesion depth, but not diameter or volume.

Animals↗
PubMed1998

Surgical staplers for vascular control of hepatic veins and portal structures in major hepatic resection.

Phenomenal progress has occurred in the art of liver resection. Only a decade ago massive blood transfusion, liver failure, bile leak, or sepsis were alI frequent attendants of major resection, and intraoperative death from torrential bleeding from hepatic veins or vena cava was not uncommon. Now, major liver resection may be accomplished routinely without blood transfusion, and operative mortality of 0% to 2% is standard in expert hands. Uncontrolled hemorrhage remains the primary cause of intraoperative death. Mortality in the early postoperative period is usually related to delayed hemorrhage, inadequate hepatic reserve, or injury to vital blood supply or biliary drainage in the liver remnant.

Journal Article↗
PubMed1998

Veno-veno bypass of the inferior vena cava in trauma, tumor, and transplantation.

Interrupting the venous return from below the diaphragm is usually associated with sudden hypotension, hypovolemic cardiac failure, and increased bleeding secondary to acute venous hypertension and hepatic congestion. Shaw, Starzl, and Griffith developed a veno-veno bypass technique to shunt the somatic and splanchnic venous return around the retrohepatic vena cava to the superior vena cava. This permitted continuation of venous return and simultaneous blood warming, allowing surgeons to perform complex procedures in a dry operative field. These bypass techniques have evolved since their introduction in the 1980s and are now being applied for the removal of otherwise nonresectable tumors of the liver, adrenal gland, and kidney. Further, traumatic injuries to the hepatic veins and the retrohepatic cava associated with a high mortality rate can be repaired safely using vascular isolation techniques and bypass.

Journal Article↗
PubMed1998

Schwannoma of the pancreas: a report of two cases and a review of the literature.

Schwannoma of the pancreas is a rare neoplasm. It generally affects older adults (average age, 60 yr). The sex incidence is equal. These tumors vary considerably in size and approximately two-thirds are partially cystic, which can cause clinical confusion with epithelial neoplasms. Histologically, they are typical schwannomas, with Antoni A and Antoni B areas, and they do not cause undue diagnostic problems once adequate tissue is examined histologically.

Aged↗
PubMed1997

Idiopathic thrombocytopenic purpura in a liver transplant recipient with previous primary biliary cirrhosis.

The loss of immunotolerance has been implicated in the pathogenesis of both primary biliary cirrhosis (PBC) and idiopathic, immune-mediated thrombocytopenic purpura (ITP). An association between these two autoimmune diseases has been well described. We describe a 41-year-old woman in whom ITP developed 457 days after liver transplantation for PBC while receiving immunosuppressive medications sufficient to maintain allograft function. Our case report, the first to describe post-transplant ITP in association with PBC, demonstrates the persistence of the underlying immune dysregulation of PBC after transplantation. The practice of decreasing the dosage of immunosuppressive medication to maintenance levels after transplantation may unmask the effects of this defect in immunotolerance.

Adult↗
PubMed1997

Late recurrent post-transplant primary biliary cirrhosis in British Columbia.

Late recurrent primary biliary cirrhosis (PBC) following orthotopic liver transplant remains a controversial topic. The first documented case of recurrence occurring in 16 patients transplanted for PBC and followed at the authors' institution for longer than one year is presented. A 54-year-old man transplanted for PBC developed a cholestatic pattern of enzyme elevation on post-transplant day (PTD) 1305. Repeat antimitochondrial antibody was strongly positive (1:300 to 1:400). A liver biopsy revealed severe bile duct damage, lymphocytic cholangitis, focal periductal noncaseating granuloma and minimal endotheliitis. Recurrent PBC was diagnosed. At the time of orthotopic liver transplant this patient received induction immunosuppression with OKT3 crossed over to cyclosporine (CsA), azathioprine (AZA) and prednisone. AZA was discontinued early and maintenance CsA tapered to a target trough level of 150 to 200 ng/mL by PTD 365. Prednisone was withdrawn by PTD 664. CsA levels during PTDs 1225 to 1305 (before elevation of hepatobiliary enzymes) were below target at 114 to 166 ng/mL. Of the 16 patients, all but three were maintained on CsA, AZA and prednisone. One was on CsA (trough levels on target) and AZA; the other two, including the patient with recurrent PBC, were on CsA only. The trough CsA level of the patient without recurrent PBC has been within the target range. The authors speculate that the underlying defect in immunoregulation in PBC persists post-transplant and that in the patient without recurrent PBC this defect was unmasked by lowered maintenance immunosuppression--allowing recurrence of PBC in a previously stable liver allograft.

Biopsy, Needle↗
PubMed1997

Radiofrequency ablation in surgery.

Recently, hyperthermia has been employed clinically as one of a variety of multimodal therapies for cancer. Hyperthermia has been applied locally, regionally, and systemically to various tumors. Local or regional hyperthermia has the advantage that a localized tumor can be heated to temperatures higher than 420 C, the maximum for total-body hyperthermia. There is mounting evidence to support a hypothesis that cancer cells are more selectively sensitive to heat than are normal cells, due to the poor blood supply of neoplastic tissue and the decreased vasodilatation capacity of the neovascular bed.

Journal Article↗
PubMed1996

Medium aperture meso-caval shunts reliably prevent recurrent variceal hemorrhages.

BACKGROUND: Objectives of partial medium aperture mesocaval shunts (MCS) include reduction of portal hypertension to prevent recurrent variceal hemorrhage, preservation of portal flow through liver while maintaining an intact porta hepatis to facilitate a future liver transplant (OLTx). PATIENTS AND METHODS: Fifteen patients were retrospectively analyzed to review the indications for the procedure, its short- and long-term complications as well as patency and functional status of the shunt. They were followed for a period of 21 months. RESULTS: The perioperative and long-term mortality rate was 0%. Rebleeding rate perioperatively and in follow-up was 0%. Early shunt nonfunction was 13% and post-shunt encephalopathy (PSE) was 20%. The encephalopathy was grade I to II and controlled medically. Abdominal ultrasound and Doppler confirmed 13 patent shunts (2 patients did not agree to ultrasound) with preserved hepatopetal flow in 10. CONCLUSIONS: Medium aperture MCS utilizing ringed polytetrafluoroethylene (PTFE) grafts safely and reliably prevent recurrent variceal hemorrhage. Encephalopathy is infrequent and mild. This technique preserves the portal venous anatomy making a future OLTx technically easier.

Adult↗
PubMed1996

Late acute rejection occurring in liver allograft recipients.

To study the effect of immunosuppressive reduction on the incidence and consequence of late acute rejection (LAR) in liver allograft recipients, mean daily prednisone dose, mean cyclosporine A (CsA) trough and nadir levels were retrospectively reviewed for the nearest 12-week period preceding six episodes of LAR in five liver allograft recipients (group 1). Results were compared with those from a cohort of 12 liver allograft recipients who did not develop LAR (group 2). LAR was defined as acute rejection occurring more than 365 days post-transplantation. Median follow-up for both groups was similar (504 days, range 367 to 1050, versus 511 days, range 365 to 666, not significant). Mean trough CsA levels were lower in patients with LAR compared with those without (224 +/- 66 ng/mL versus 233 +/- 49 ng/mL) but the difference was not statistically significant. In contrast, mean daily prednisone dose (2.5 +/- 1.6 mg/day versus 6.5 +/- 2.9 mg/day, P = 0.007) and CsA nadir values (129 +/- 60 ng/mL versus 186 +/- 40 ng/mL, P = 0.03) were significantly lower in patients who developed LAR compared with those who did not. Five of six episodes (83%) of LAR occurred in patients receiving less than 5 mg/day of prednisone, versus a single LAR episode in only one of 12 patients (8%) receiving prednisone 5 mg/day or more (P = 0.004). In all but one instance, LAR responded to pulse methylprednisolone without discernible affect on long term graft function. The authors conclude that liver allograft recipients remain vulnerable to acute rejection beyond the first post-transplant year; and reduction of immunosuppressive therapy, particularly prednisone, below a critical, albeit low dose, threshold increases the risk of LAR.

Acute Disease↗
PubMed1995

Laparoscopic staging of intraabdominal malignancy.

Laparoscopic visualization techniques have improved dramatically over the last 5 years and have led to reassessment of the laparoscope for use in the staging of intraabdominal malignancy. One hundred sixty-two consecutive cases undergoing preoperative staging laparoscopy from January 1988 to December 1993 were reviewed in order to determine the value of laparoscopy as a staging tool. Indications for staging laparoscopy were predominantly hepatopancreaticobiliary (85%); however, other primaries such as stomach and colon were included. In 36% of cases information found at laparoscopy precluded resection and prevented unnecessary laparotomy. Additional information that was felt to be helpful in planning resection was found in 30% of cases. In 12% of cases unresectability was found only at the time of laparotomy and was missed by staging laparoscopy. We conclude that laparoscopy is a useful preoperative staging tool and can help avoid unnecessary laparotomy for intraabdominal malignancy in one-third of patients.

Abdominal Neoplasms↗
PubMed1995

Aprotinin reduces the need for blood products during liver transplantation.

BACKGROUND: Bleeding complications and blood product consumption have been a major concern during liver transplantation. Prevention of plasminogen activation and fibrinolysis by aprotinin administration has been shown to reduce perioperative bleeding during operations associated with high blood-product consumption. PATIENTS AND METHODS: Use of blood-products (packed red cells, frozen plasma, platelets, and cryoprecipitate) was analyzed both during the three stages of orthotopic liver transplantation and during total hospitalization of the 26 patients transplanted without aprotinin and the subsequent 40 patients with aprotinin. A similar analysis was performed for 15 patients immediately before and after the introduction of aprotinin to eliminate the "learning curve" effect for liver transplantation. The effect of epsilon-amino-caproic acid was analyzed as 13 patients received neither epsilon-aminocaproic acid nor aprotinin and 13 patients received epsilon-aminocaproic acid but not aprotinin. RESULTS: There was a significant reduction in total hospital use of cryoprecipitate, frozen plasma, platelets, and red cells in the aprotinin-treated patients. This reduction was seen during the anhepatic and reperfusion stages of liver transplantation. There was no difference in blood product consumption between the groups who were or were not treated with epsilon-aminocaproic acid. CONCLUSION: Aprotinin significantly reduces the need for red cell, frozen plasma, platelet, and cryoprecipitate transfusion use during orthotopic liver transplantation, and appears to be more efficacious than epsilon-aminocaproic acid.

Adolescent↗
PubMed1995

Venovenous bypass in renal cell carcinoma with caval tumor thrombus.

We describe two patients with a T3bN2M0 renal cell carcinoma with caval extension to the hepatic veins in which we successfully utilized extracorporeal femoralaxillary venovenous bypass for tumor thrombus resection. The inherent advantage of this modified venovenous bypass are discussed with a current review of the literature.

Journal Article↗
PubMed1995

Laparoscopic cholecystectomy: a continuing plea for routine cholangiography.

The purpose of this clinical study was to demonstrate the usefulness of routine intraoperative cholangiography (IOC) and the safety of laparoscopic cholecystectomies (LC) in a community hospital. There were no ductal injuries and perioperative complications were extremely low. Patients (n = 236) with symptomatic gallstone disease, acalculus cholecystitis, or gallbladder polyps underwent LC from March 1991 to June 1993. During this period two patients were not considered appropriate candidates for this procedure. There were 172 women and 64 men ranging in age from 15 to 84 years. Four had preoperative endoscopic retrograde cholangiopancreatographies (ERCPs) for suspected choledocholithiasis. Elective LC was performed on 194 patients and emergency LC on 42 patients. The average operating time for elective LCs was 89 min and 97 min for emergency LCs. Thirty-six percent of patients had previous abdominal or pelvic surgery. IOC was attempted in 99% of patients and successful in 89%. Five percent had choledocholithiasis. Laparoscopic duct exploration was performed on four patients. Six patients had postoperative ERCP with stone extraction. Three percent of elective patients had additional surgery. One patient had LC during pregnancy (17 weeks), with a normal recovery and successful outcome of the pregnancy. Six elective and four emergency patients were converted to open cholecystectomy, a conversion rate of 4%. There were no ductal or vascular injuries, intraoperative haemorrhages or deaths. There were one small bowel laceration (0.4%). Postoperative complications included seven wound infections (3%), four bile leaks (2%), three trocar site haemorrhages (1%), one intraabdominal haemorrhage (0.4%), one suspected halothane hepatitis (0.4%), one drug-induced cholestatic jaundice (0.4%), and one subcutaneous emphysema (0.4%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Markedly elevated serum CA 19-9 levels in a case of chronic pancreatitis.

Serum levels of carbohydrate antigen (CA) 19-9 exceeding 1000 U/mL are considered highly specific for pancreatic cancer and have not been reported in nonmalignant pancreatic disease. A young man with obstructive jaundice, a serum CA 19-9 level of 2350 U/mL and a mass in the head of the pancreas, seen on computed tomography, was found to have chronic pancreatitis without malignant disease. This case demonstrates that a markedly elevated serum level of CA 19-9 can occur in nonmalignant pancreatic disease and emphasizes the need for a histologic diagnosis of malignancy even if the clinical diagnosis of pancreatic cancer seems certain.

Adult↗
PubMed1994

Effect of a 21-aminosteroid, U74006F, on lipid peroxidation and glomerulotubular function following experimental renal ischemia.

In order to investigate the capacity of the 21-amino-steroid, U74006F, to mitigate ischemic/reperfusion injury (IRI), we studied lipid peroxidation and glomerulotubular function in a rat model of IRI. U74006F, superoxide dismutase (SOD), and their respective vehicles were administered preischemia and prereperfusion to Brown Norway rats subjected to 45 or 60 min of bilateral normothermic ischemia. Lipid peroxidation was assessed by assay of thiobarbituric acid reactive products (TBA-RP) in a forced peroxidation reaction with t-butylhydroperoxide while renal function was assessed by timed determinations of serum creatinine, creatinine clearance, urine volume, and fractional excretion of sodium (FeNa+). Twenty-four hours following a 60-min ischemic insult and uninephrectomy, the glomerular filtration rate (GFR) was markedly reduced in the IRI + vehicle group compared to controls as reflected by a significant elevation in mean serum creatinine (0.138 +/- 0.018 vs 0.045 +/- 0.002 mumole/liter, P < 0.05) and a significant reduction in mean creatinine clearance (0.200 +/- 0.076 vs 1.130 +/- 0.153 ml/min, P < 0.05). Neither U74006F nor SOD afforded protection against this marked fall in GFR. In contrast, U74006F significantly attenuated both the diuresis (UVol) and the increase in fractional excretion of filtered sodium (FeNa+) seen post-IRI. At 24 hr post-IRI, mean UVol was 22.50 +/- 4.57 ml/day and FeNa+ 1.35 +/- 0.16% in the IRI+vehicle group compared to 11.48 +/- 2.00 ml/day and 0.82 +/- 0.22%, respectively, in the IRI+U74006F group (P < 0.05). While SOD also proved partially protective of tubular function, the effect was not as pronounced as that observed with U74006F.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗