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Biomedical subjects

B R Taylor

Publications and source records attributed to B R Taylor.

At least 37 records · Page 2Linked to original sources

Liver transplantation for hepatocellular carcinoma.

Twenty-nine patients with hepatocellular carcinoma (HCC) underwent orthotopic liver transplantation (OLTx) at the University of Toronto. Four patients did not have cirrhosis. Of the 25 patients with cirrhosis, 19 had known or suspected HCC before OLTx. Eleven patients tested positive for the hepatitis B surface antigen (HBsAg). No patients received adjuvant chemotherapy. None of the patients have developed recurrent HCC in a follow-up of 9 to 87 months (mean: 33 months). The actuarial post-transplant survival of all patients at 3 months, 1 year and 3 years was 75%, 61%, and 46%, respectively. The survival of HBsAg-negative patients was 69% at 3 years, whereas HBsAg-negative patients had a 3-year survival of 18% (p = 0.045). These results suggest that OLTx for carefully selected patients with otherwise unresectable HCC is associated with a low risk of recurrence. HBsAg-positive patients with HCC have a high mortality, suggesting that they make poor candidates for OLTx.

Adult↗

Genomic structure of rat liver aryl sulfotransferase IV-encoding gene.

This report contains the first description of the genomic structure for a sulfotransferase (ST). The gene (ASTIV) encodes rat hepatic aryl ST IV, also known as tyrosine-ester ST (EC 2.8.2.9). A phage genomic clone containing 70% of the 3' AST gene coding sequence was isolated after screening a rat genomic library with an ASTIV cDNA. The remaining 5' sequence was determined from a PCR product obtained from rat genomic DNA and ASTIV cDNA-specific primers. ASTIV spans 3.5 kb and contains eight exons and seven introns. The fourth intron of this gene contains sequences homologous to rodent B1 repetitive elements and an Alu repeat found in rat. An alignment of the primary structures of ten different ST revealed several conserved regions, as well as a putative binding site for the cofactor for enzymatic sulfation reactions, 3'-phosphoadenosine-5'-phosphosulfate.

Amino Acid Sequence↗

Complete foregut duplication.

Alimentary tract duplications are rare congenital anomalies with the majority identified in the pediatric age group. However, duplications may be seen in the adult population and require operative excision. A 53-year-old man was seen with vague, nonspecific symptoms and was found to have a complete esophageal and gastric duplication with communication to the normal alimentary tract. Appropriate-for-structure epithelium was noted throughout the length of the duplication.

Barium Sulfate↗

Selective or total shunts for variceal bleeding.

Shunt surgery remains an important therapeutic option in the management of variceal bleeding, and both total and selective shunts have a role to play. The distal shunt is associated with a lower long-term encephalopathy rate and may yield better survival in the nonalcoholic patient; it is, therefore, the preferred shunt in the elective situation. The total shunt is technically easier to perform and more widely available; it is, therefore, preferred in the emergency situation. Ordinarily, the side-to-side and end-to-side shunts have similar outcomes; however, in patients with hepatic venous outflow obstruction and patients with intractable ascites, the side-to-side shunt should be used.

Esophageal and Gastric Varices↗

Reliability and validity of the objective structured clinical examination in assessing surgical residents.

The purpose of this research was to assess reliability and construct validity of the objective structured clinical examination (OSCE) for evaluating the clinical skills of surgical residents. Reliability refers to precision of the examination and construct validity to the degree to which the examination can discriminate between different levels of training. Twenty-seven second postgraduate year surgical residents took a 38-station OSCE representing seven surgical specialties and that tested history-taking, physical examination, problem-solving, technical skills, and attitudes. A couplet methodology was used wherein a patient encounter was followed by written questions aimed at testing problem-solving and patient management capabilities. Thirty-six standardized patients were trained and 36 surgeons served as examiners marking from structured checklists. Overall reliability, Cronbach's alpha, was 0.89. Construct validity was examined by comparing the scores of the residents with those of a group of graduates of foreign medical schools applying for a "pre-internship" program. For 17 of 19 stations that both groups took, the residents performed significantly better (p less than 0.01). Individual station validity was significant for 32 of 38 stations (r = 0.36 to 0.82, p less than 0.05). The examinations took 3.83 hours at a cost of $5,293 (Canadian dollars). The OSCE has been shown to be a reliable method of assessing clinical skills of surgical residents, construct validity has been established, and inter-item validity confirmed. Reliabilities achieved exceed those traditionally required for both acceptance and promotion decisions.

Analysis of Variance↗

Emergency surgical treatment of variceal hemorrhage.

Emergency surgery should be considered one of the treatment options for the patient with acute variceal bleeding in whom the usual nonsurgical modes of therapy fail, and who is deemed fit to tolerate a major operation. A total shunt (portacaval or mesocaval) is recommended for most of these patients, although a distal splenorenal shunt might be considered for some very good risk, nonalcoholic patients who have only moderate bleeding. Devascularization procedures have a limited role in the emergency situation, but they may be useful in patients who are nonshuntable because of splanchnic venous thrombosis. The Sugiura type of operation is appropriate for the nonalcoholic patient, and esophageal transection is appropriate for the alcoholic patient with cirrhosis. Patients with end-stage nonalcoholic liver disease should also be considered for liver transplantation.

Emergencies↗

Treatment of primary liver graft nonfunction with prostaglandin E1.

Primary nonfunction following orthotopic liver transplantation is characterized by rapidly rising serum transaminases, minimal bile production, and severe coagulopathy, which can progress to hypoglycemia, hepatic encephalopathy, and acute renal failure. Untreated it has a mortality of over 80% and to date the only treatment has been retransplantation. As a result of the beneficial effect of Prostaglandin E1 infusion in patients with fulminant hepatic failure, this trial was conducted to determine whether PGE1 would be of value in primary nonfunction. We have encountered 16 cases of primary nonfunction in 94 liver transplants, an incidence of 17%. Initially in the program, there were 6 occurrences of nonfunction that did not receive PGE1; 3 underwent retransplantation (2 survivors), 2 died awaiting another liver, and in one recovery of hepatocellular function occurred with supportive care but the patient died of cytomegalovirus infection. Ten patients received PGE1 within 4-34 hr of transplantation. Within 12 hr of treatment, 8 patients responded with a significant fall in the AST (129 U/hr) whereas, in the untreated group, the AST continued to rise (267 +/- 102 U/hr) at the same rate as prediagnosis (337 +/- 95 U/hr). At the conclusion of the infusion (4-7 days) in the 8 responders, there were significant decreases in AST (4386 +/- 546 U/L to 102 +/- 21 U/L), prothrombin time (22 +/- 2 to 12 +/- .4 sec) and partial thromboplastin time (45 +/- 3-29 +/- 4 sec), and significant increases in coagulation factor V (26 +/- 8 to 95 +/- 12%) and factor VII (10 +/- 5 to 61 +/- 4%). No serious side effects occurred, although 2 patients developed diarrhea, and abdominal cramps. Two patients treated with PGE1 were retransplanted at 10-36 hr and were considered nonresponders. Graft survival was 80% in the PGE1-treated group and 17% in the untreated group (P less than 0.05) and patient survival was 90% and 33%, respectively. This study suggests a potential benefit of PGE1 in the treatment of primary nonfunction.

Alprostadil↗

Emergency portasystemic shunting in cirrhotics with bleeding varices--a comparison of portacaval and mesocaval shunts.

Despite the best conservative measures available for the control of major variceal hemorrhage, some patients either continue to bleed, or rebleed early, and require emergency surgery. One hundred patients with cirrhosis and uncontrolled bleeding were treated with emergency portasystemic shunts between 1968 and 1983. Fifty eight patients had end-to-side portacaval shunts and 42 had Dacron interposition mesocaval shunts. Both groups were comparable with respect to age, sex and prevalence of alcoholism. There was an increased severity of liver disease as assessed by Child's class in the mesocaval group of patients. Overall in-hospital mortality was 31% with no significant difference demonstrated between the mesocaval group (28%) and the portacaval group (33%), nor between alcoholic cirrhotics (34%) and non-alcoholic cirrhotics (21%). Mortality rates based on severity of liver disease were: Child's A (1/6) 17%, Child's B (9/48) 19%, and Child's C (21/46) 46%. There was a statistically significant difference between Child's A & B and Child's C (p less than 0.01). Four patients were lost to follow-up. No significant differences were found in 5 year survival by life table analysis comparing portacaval (39%) vs. mesocaval (28%) groups or alcoholic cirrhotics (36%) vs. non-alcoholic cirrhotics (29%). Encephalopathy in survivors was absent in 46%, mild in 28% and severe in 26% of patients. There was no significant difference in encephalopathy rates following portacaval or mesocaval shunting. Neither operation was clearly superior and choice of operation can be made on the basis of technical and anatomical factors and surgeon experience. Emergency shunting remains a useful option for patients with variceal bleeding refractory to other more conservative therapy, and is associated with acceptable early mortality and long term survival rates.

Adult↗

Magnetic resonance imaging, computed tomography, and radionuclide scintigraphy in detection of liver metastases.

A series of 100 patients with suspected hepatic metastases was studied with magnetic resonance (MR), unenhanced computed tomography (CT), and radionuclide (RN) scintigraphy. Each set of images was read by three clinicians using a five-point scale to allow receiver operating characteristic (ROC) analysis using truth data derived from clinical review. Performance was measured by the areas under the ROC curves (0.940 +/- .018 for MR, 0.951 O +/- .013 for CT and 0.943 +/- .013 for RN) which were statistically not significantly different. We conclude that at their present level of development these three diagnostic examinations have equivalent performance and that MR is not superior in the detection of hepatic metastases.

Evaluation Studies as Topic↗

Nonparasitic cysts of the liver. The case for conservative surgical management.

The recommended treatment for nonparasitic hepatic cysts (NPHC) has been either resection or drainage into a Roux loop of jejunum. From 1970-1984 a more conservative approach to NPHC was adopted in 22 patients with large symptomatic cysts. Seventeen patients were treated with simple unroofing without complication. By comparison, two of three patients treated by Roux-en-Y drainage developed infected hepatic cysts that required subsequent surgical drainage. Patients treated by external drainage without unroofing or hepatic resection had either cyst recurrence or complications. In conclusion, wide unroofing is the treatment of choice for NPHC even when the cyst fluid is bile stained.

Adult↗