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Biomedical subjects

J G Turcotte

Publications and source records attributed to J G Turcotte.

At least 73 records · Page 4Linked to original sources
PubMed1987

Quantitative scintigraphy with deconvolutional analysis for the dynamic measurement of hepatic function.

A mathematical technique known as deconvolutional analysis was used to provide a critical and previously missing element in the computations required to quantitate hepatic function scintigraphically. This computer-assisted technique allowed for the determination of the time required, in minutes, of a labeled bilirubin analog (99mTc-disofenin) to enter the liver via blood and exit via bile. This interval was referred to as the mean transit time (MTT). The critical process provided for by deconvolution is the mathematical simulation of a bolus injection of tracer directly into the afferent blood supply of the liver. The raw data required for this simulation are obtained from the intravenous injection of labeled disofenin, a member of the HIDA family of radiopharmaceuticals. In this study, we perform experiments which document that the simulation process itself is accurate. We then calculate the MTT under a variety of experimental conditions involving progressive hepatic ischemia/reperfusion injury and correlate these results with the results of simultaneously performed BSP determinations and hepatic histology. The experimental group with the most pronounced histologic findings (necrosis, vacuolization, disorganization of hepatic cords) also have the most prolonged MTT and BSP half-life. However, both quantitative imaging and BSP testing are able to identify milder degrees of hepatic ischemic injury not reflected in the histologic evaluation. Quantitative imaging with deconvolutional analysis is a technique easily adaptable to the standard nuclear medicine minicomputer. It provides rapid results and appears to be a sensitive monitor of hepatic functional disturbances resulting from ischemia and reperfusion.

Animals↗
PubMed1987

Pediatric renal transplantation with an emphasis on the prognosis of patients with chronic renal insufficiency since infancy.

In this report recent experience with renal transplantation in 43 children who were 17 days to 16 years old was reviewed. One-year patient survival rate was 98%, and overall one-year graft survival rate was 68%. One-year graft survival rate was 73% for cyclosporine-treated patients and 78% for recipients of related donor kidneys. A subpopulation of patients affected with renal insufficiency since infancy was analyzed separately to evaluate the prognosis of these patients, who have previously been reported to be a high risk for permanent neurologic, developmental, and growth retardation. All 16 such patients underwent transplantation. Gross motor delay that was noted in 31% of patients before surgery resolved in all patients after transplantation. No evidence of severe developmental delay was noted after transplant and seven of 11 patients with successful transplants had evidence of catch-up growth. Overall renal transplantation is a safe and effective procedure for children with renal failure, and even the patients at highest risk for growth and developmental failure caused by renal insufficiency show potential for rehabilitation after transplantation.

Adolescent↗
PubMed1986

Early variceal rebleeding after successful distal splenorenal shunt.

Of 77 patients with repeated variceal hemorrhage who underwent distal splenorenal shunt, five (6.5%) developed rebleeding despite a patent splenorenal anastomosis. Three of the five patients died. Early variceal rebleeding usually indicates shunt thrombosis but may occur with a patent anastomosis. Anatomic or functional left renal vein and/or splenic vein hypertension producing incomplete variceal decompression is generally the cause. Ineffective separation of the main portal vein from the gastrosplenic venous plexus may coexist and further intensify variceal congestion. Urgent angiographic studies and direct shunt catheterization with measurement of splenic vein, left renal vein, and inferior vena cava pressures should be performed to plan appropriate therapy. A significant gradient between the splenic and renal veins is evidence of an unsatisfactory anastomosis and should be managed by balloon angioplasty or reoperation. High splenic and left renal vein pressures with a gradient of more than 10 mm Hg between the renal vein and the inferior vena cava indicate renal vein hypertension. Initial therapy should include serial injection sclerotherapy, as renal vein hypertension will usually resolve over time as additional collaterals develop. However, persistent or recurrent variceal hemorrhage may require total portal decompression to bypass the restrictive left renal vein segment.

Adult↗
PubMed1986

Papillary epithelial neoplasm of the pancreas in the pediatric population.

Cancer of the pancreas is an uncommon entity in the pediatric population and there have been only three reports of what may be termed papillary epithelial neoplasm of the pancreas. We recently treated a young patient with this tumor, and comparison with the previously reported cases suggests a specific histologic and clinical picture, preferred treatment approach, and likely prognosis.

Adolescent↗
PubMed1986

Detrimental effects of four hours of cold storage on porcine pancreaticoduodenal transplantation.

Transplantation of the pancreaticoduodenal allograft (PDA) has recently been advocated as a technique that is superior to the use of the segmental allograft. However, the effect of simple cold storage preservation on the PDA has not been studied. We investigated the effect of 24 and 4 hours of cold storage in Eurocollins solution on porcine PDA function after transplantation in pancreatectomized pigs. A regimen of cyclosporine and prednisone was used, which prevented rejection for at least 28 days after transplantation. Cold storage preservation for 24 hours uniformly resulted in PDA failure. Compared with recipients of immediately transplanted PDA, recipients of PDA cold stored for 4 hours had marked plasma hyperamylasemia (10,000 U/L versus 1932 U/L), relative glucose intolerance (K value -2.15 versus -2.66), hypoinsulinemia (peak immunoreactive insulin 11.0 microU/ml versus 34.7 microU/ml), and an abnormal pattern of insulin secretion as demonstrated with intravenous glucose tolerance testing. There was also a higher incidence of technical complications in the group transplanted with cold-stored PDAs. Our results suggest that there is a detrimental effect on porcine PDA function after only 4 hours of cold storage in Eurocollins solution.

Amylases↗
PubMed1986

Immunoreactive anionic and cationic trypsins in serum after experimental porcine pancreatic transplantation.

Immunoreactive anionic and cationic trypsins (irAT and irCT) were measured in blood samples taken daily from 20 pigs during 60 days after whole organ pancreatic transplantation. Immunosuppression was discontinued on the twenty-eighth day after transplantation. IrAT concentrations showed three distinct peaks, the first immediately after operation, the second around the seventh day after operation, and the third irAT peak was seen 2 to 9 days after discontinuation of immunosuppression therapy. IrCT levels paralleled the irAT levels only in the first peak immediately after transplantation. After this there was a dissociation between the concentrations of the two immunoreactive trypsins, with low irCT levels and high irAT levels. Increased irAT levels heralded rejection of the pancreatic allograft by 4 to 30 days (median 20 days) in 13 of the 16 rejecting animals (80%). In addition, low irCT levels preceded hyperglycemia in 13 of the 16 rejecting pigs by 2 to 47 days (median 21 days). The first postoperative peak of immunoreactive trypsins is thought to be related to the operative and storage trauma, whereas the second and third peaks are thought to reflect a rejection process. The results suggest that immunoreactive trypsins can be used as markers for pancreatic allograft rejection.

Animals↗
PubMed1985

Biological activity of platelet activating factor-amidophosphonate (PAF-AP), a novel phosphonolipid selective inhibitor of platelet activating factor (PAF).

A novel amidophosphonate analog of Platelet Activating Factor (PAF), trimethyl (3-phosphonopropyl) ammonium hydroxide (R)-mono[2-acetamido-3-(hexadecyloxy)propyl] ester (PAF-AP), was synthesized. A potent inhibitor of aggregation induced by Platelet Activating Factor, arachidonic acid, Ca2+-ionophore, ADP, and thrombin, PAF-AP had no or very little effect on aggregation induced by epinephrine and collagen. Inhibition of phospholipase A2 and C2 activity was suggested from suppression of release of [14C]-arachidonic acid from pre-labeled platelet glycerophospholipids.

Adenosine Diphosphate↗