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Biomedical subjects

R Lapointe

Publications and source records attributed to R Lapointe.

At least 55 records · Page 3Linked to original sources
PubMed1993

Hepatic artery: effect of a meal in healthy persons and transplant recipients.

Thirty healthy volunteers and 12 liver allograft recipients (two with cirrhotic changes seen at microscopy) were given a standard meal. Doppler sonography of the right and left hepatic arteries, the superior mesenteric artery, and the portal vein was performed. The change in hepatic arterial resistance was evaluated with the resistive index (RI). After the standard meal, portal venous flow increased in both the healthy volunteers and allograft recipients (more so in the latter group). Superior mesenteric arterial RI decreased in all subjects. A postprandial increase in hepatic arterial RI, likely reflecting constriction of the hepatic artery, was seen in both groups. It was absent in the two patients with recurrent transplant cirrhosis. These results show the importance of examining hepatic arterial flow in the fasting subject, since high resistance after a meal may be falsely interpreted as a sign of disease. Absence of a postprandial change in resistance of the hepatic artery could signal abnormal liver function.

Adult↗
PubMed1993

[Right diaphragmatic paralysis after liver transplantation].

Right hemidiaphragm paralysis has been previously documented in patients after orthotopic liver transplantation (OLT) and it may contribute to the development of postoperative pulmonary problems. It has been postulated that a crush injury to the right phrenic nerve during OLT is the cause of dysfunction of the right hemidiaphragm. To assess the incidence and effect of right phrenic nerve injury after OLT, we prospectively studied 51 adult liver recipients that we compared with twelve patients who underwent liver resection (LR) without suprahepatic vena cava clamping. We studied the diaphragm excursion by ultrasound, the pulmonary function tests and the transcutaneous phrenic nerve conduction. Righ phrenic nerve injury and hemidiaphragm paralysis occurred respectively in 79% and 38% of the liver recipients but not after LR. Conduction along the right phrenic nerve was absent in 53% of the patients and reduced in another 26%. Left phrenic nerve conduction and left hemidiaphragm excursion were normal in both groups. Liver recipients with no conduction in the right phrenic nerve had a significantly greater decrease in vital capacity in the supine position compared to those with some conduction (29% vs 14%; P < 0.001). However, neither the time on the ventilator or the hospital stay were significantly different between the two groups. Complete recovery of phrenic nerve conduction and diaphragm function may take up to nine months. Right phrenic nerve injury is common after OLT and causes right hemidiaphragm dysfunction.

Adolescent↗
PubMed1993

[Technique to minimize the incidence of hepatic artery thrombosis in pediatric liver transplantation].

Hepatic artery thrombosis is a life-threatening complication after pediatric liver transplantation. We reviewed our experience in 62 children who received 72 liver transplant (69 whole grafts and 3 reduced-size grafts) between January 1984 and December 1991. They ranged in age from 6 months to 16 years (mean 5.8 years). Fifteen children (22%) were under 2 years and 10 patients (14%) were between 2 and 5 years. Forty-eight grafts in older children (age: 1-16 years, x = 7 years had an anastomosis between the donor hepatic/celiac artery and the recipient hepatic of splenic artery (A-A). Three thromboses occurred in this group for an incidence of 6.2%. Two others types of arterial reconstruction were used in 24 children who were significantly younger (6-120 months, x = 47 months, p < 0.01). Eight grafts had an anastomosis between the donor celiac artery and the recipient aorta (A-Ao). No thromboses occurred in this group. Sixteen grafts were revascularized using a donor aortic conduit anastomosed to the recipient aorta (AC) with a 12.5% (2 to 16) incidence of thrombosis. The incidence of arterial thrombosis for the entire group was 6.9%. In conclusion, by using the recipient aorta for arterial reconstruction, a low incidence of hepatic artery thrombosis can be achieved even in the group of younger patients who are the highest risk for this complication.

Adolescent↗
PubMed1990

Isolated perfused cirrhotic human liver obtained from liver transplant patients: a feasibility study.

Cirrhotic livers obtained from eight patients who underwent orthotopic liver transplantation were perfused through the portal vein and hepatic artery in a closed recycling system for periods ranging from 2 to 7 hr. An average perfusion flow of 451 ml/min was used, with about 80% coming from the portal vein and 20% from the hepatic artery. The livers appeared to remain viable as assessed by gross appearance, stable portal vein and hepatic artery pressures, oxygen consumption and bile production. The extraction ratio of indocyanine green by the perfused livers averaged 0.098 (range = 0.023 to 0.168); that of propranolol averaged 0.445 (range = 0.126 to 0.813). Using the multiple-indicator dilution-curve method, shunts greater than 15 microns in diameter were demonstrated between the portal and hepatic veins in six of eight cases, whereas shunts from the hepatic artery to the hepatic veins were absent. Perfusion of human livers obtained during hepatic transplantation is a fairly simple procedure that will allow researchers to gain new insights into cirrhosis in humans.

Angiography↗
PubMed1987

Emergency portacaval shunt for variceal hemorrhage. A prospective study.

Emergency portacaval shunt for variceal bleeding is associated with a high operative mortality, particularly if used as a last resort. Because of this, a strong case has been made against emergency shunt. This report describes an experience with emergency portacaval shunt for the treatment of variceal bleeding when used systematically after hemodynamic stabilization and control of the bleeding episode with balloon tamponade, if necessary, in patients with mild or moderate liver disease. The population studied comprised 62 consecutive patients who rebled from varices while participating in a controlled trial of propranolol for the prevention of rebleeding. Of the 62 patients, nine died of massive hemorrhage and 53 survived the hemorrhage. Of the 53 survivors, 11 had severe liver disease and were not considered for shunt surgery. Of the remaining 42 patients with mild or moderate liver disease, 36 had emergency central portacaval shunt. The interval between endoscopic diagnosis of variceal bleeding and surgery averaged 19 +/- 3 hours (mean +/- SE). The operative mortality rate, defined as in-hospital mortality, was 19%. One- and 2-year survival rates were 78% and 71%, respectively. The incidence of postoperative hepatic encephalopathy was 36%; all patients responded favorably to protein restriction and lactulose. Thus, under specific conditions, emergency portacaval shunt results in an acceptable long-term survival rate. In patients with mild or moderate liver disease, emergency portacaval shunt should be considered when other forms of treatment for the prevention of variceal rebleeding have failed.

Emergencies↗
PubMed1986

Peripheral power variations in progressive addition lenses.

The peripheral powers were studied in two types of progressive addition lenses: the AO Ultravue 28 and the Essilor Varilux 2. The marginal dioptric power was measured with respect to the vertex sphere with a device adapted to a Nikon projection vertexometer. The graphical representation of the results permits the power variations to be evaluated rapidly. The results demonstrate some optical characteristics of each of the lenses. Thus it is possible to establish a ratio between the peripheral astigmatism and the addition. The angular area of astigmatic zones could also be estimated.

Astigmatism↗
PubMed1986

The V-shaped artifact of the gallbladder wall.

Among 20,000 patients who had undergone abdominal or gallbladder sonographic examinations, 36 had a short V-shaped artifact originating from an hyperechoic focus in the gallbladder wall. Associated symptoms were varied and nonspecific. The 10 gallbladders excised because of associated cholelithiasis showed a thickened wall, and seven patients had diverticulosis of the wall with impacted stones. In vitro sonographic examination of five gallbladders reproduced the "V" artifact and showed that it originated from a small intramural cholesterol stone. The V artifact should be distinguished from the larger comet-tail and ring-down artifacts, which arise from metal or gas.

Adult↗
PubMed1985

Pancreatic stone protein. I. Evidence that it is encoded by a pancreatic messenger ribonucleic acid.

We have previously shown that the pancreatic stone protein (PSP) is an inhibitor of calcium carbonate crystal growth and may participate in the stabilization of the normally supersaturated pancreatic juice. Our aim in this study was to determine if PSP is a normal secretory product of the human pancreas by determining if the normal human pancreas contains a messenger RNA coding for PSP. Human pancreatic messenger RNAs were used to direct protein synthesis in a cell-free translation system. Immunoprecipitation of translation products with a monospecific antibody directed against the PSP yielded a product migrating as a single homogeneous band on sodium dodecyl sulfate-polyacrylamide gels. This product has a molecular weight of 16,000, the value expected for pre-PSP. Products selected by immunoprecipitation with antitrypsin-1 antibodies also migrated as a single band, with a molecular weight of 27,000. It is concluded that a messenger RNA coding for pre-PSP, distinct from the messenger RNA coding for pretrypsinogen, is present in human pancreas. These results support the hypothesis that PSP is a molecular entity, and not a degradation product of trypsinogen 1 or another pancreatic protein.

Animals↗
PubMed1984

Regulation of amylase messenger RNA concentration in rat pancreas by food content.

Regulation of the expression of pancreatic amylase genes was studied by comparing groups of rats fed diets with high (75%), intermediate (20%) and low (11%) carbohydrate content. Animals on the high carbohydrate diet had nine times as much amylase mRNA as those on low carbohydrate diet, and twice as much as the intermediate group, as determined by filter hybridization of equal amounts of total pancreatic RNA to an excess of a cloned rat amylase cDNA probe. Parallel results were obtained when levels of translatable amylase RNA were compared by means of an RNA-dependent rabbit reticulocyte cell-free system. Amylase mRNA-directed synthesis represented 35% of the total in the high carbohydrate group, 4% in the low group and 14% in the intermediate group. Relative rates of amylase synthesis, determined 30 min after [3H]phenylalanine injection, followed the same pattern. While 37% of total was incorporated into amylase in the high carbohydrate group, only 8% was incorporated in the low carbohydrate group, as compared with 22% in the intermediate group. These data indicate that modifications of diet composition alter the expression of pancreatic amylase genes as a consequence of changing the level of their transcript, and that pancreatic amylase production is mostly regulated at the pre-translational level.

Amylases↗
PubMed1984

[Hypertrophy of the gastrocnemius muscles: possible etiology of the popliteal artery entrapment syndrome?].

Excessive hypertrophy of the both heads of gastrocnemius has been reported as a possible etiology of a popliteal artery entrapment syndrome. However, this syndrome is rather unusual among all those young adults and athletes with hypertrophied gastrocnemius. An other factor must exist in addition of hypertrophy. We describe a patient presenting a more cranial migration of the both heads of gastrocnemius with a shorter and more proximal tendinous attachment above the femoral epicondyles. Thus, excessive hypertrophy of the both heads of gastrocnemius may be in fact the cause of a popliteal artery entrapment syndrome when there is a congenital abnormality of muscular migration.

Adult↗
PubMed1984

Bile-duct cyst with cystlithiasis: a case report.

Cystic dilatation of the biliary tree is an uncommon congenital condition, most often discovered in infancy. It should be suspected in an adult who has a history, over a long period, of intermittent pain in the right upper quadrant, episodes of jaundice or cholangitis, or both, and has a palpable mass in the right hypochondrium. Ultrasonography and especially endoscopic retrograde cholangiopancreatography allow the biliary cyst to be diagnosed preoperatively more often than previously. The authors describe the case of a 60-year-old woman with congenital cystic dilatation of extra- and intrahepatic bile ducts with cystlithiasis that followed an unusual course. Of the various theories of causation, Babbitt 's is now the most widely accepted, especially since the advent of endoscopic retrograde cholangiopancreatography. The presence of stones is an uncommon and late complication. The treatment is surgical, excision of the biliary cysts being the treatment of choice; however, Roux-en-Y choledochocystojejunostomy is performed when excision is technically impossible.

Bile Duct Diseases↗