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Biomedical subjects

J Harb

Publications and source records attributed to J Harb.

At least 19 recordsLinked to original sources
PubMed1992

Technique of hepatic vascular exclusion for extensive liver resection.

Hepatic vascular exclusion, which includes clamping of the portal pedicle along with the inferior vena cava below and above the liver, may be a useful procedure for resection of liver tumors close to the hepatic veins or the vena cava that are usually considered unresectable by conventional techniques. Since complete caval exclusion is the key to good hemodynamic tolerance and a bloodless transection of the liver parenchyma, several technical aspects of the procedure must be accomplished and are detailed.

Constriction↗
PubMed1992

Modulation of extracellular matrix glycoproteins production by in vitro interacting conditions between rat colonic fibroblasts and tumoral cells.

Mixed cultures of fibroblasts with rat colon carcinoma cell lines were used to investigate the production of extracellular matrix glycoproteins. Tumoral cells were shown to influence their production in different ways depending on the cell clone (PROb cells which in vivo produce progressive tumors and REGb cells which produce regressive ones) but also on the relative proportions of stromal and tumoral cells. When fibroblasts were predominant, the REGb cells containing mixture produced higher levels of all protein studied as compared with the PROb cells containing system. When the situation was reversed in favor of tumoral cells, REGb cells containing cocultures still produced more fibronectin, laminin and undulin, but the difference with PROb ones was reduced. On the opposite, cocultures enriched with PROb cells made more entactin and SPARC and approximately equal amounts of tenascin.

Animals↗
PubMed1992

Effects of moderate hypothermia on O2 consumption at various O2 deliveries in a sheep model.

The effects of modest hypothermia on oxygen consumption (VO2) were studied at various levels of oxygen delivery (DO2) in six sheep. Each animal was placed on cardiopulmonary bypass by extrathoracic cannulations. DO2 was varied by changing blood flow through an extracorporeal circuit. VO2 was measured spirometrically across a membrane lung. VO2 was initially measured at various levels of DO2 at normothermic temperatures (39 degrees C). The animals were then cooled to 33 degrees C. DO2 was varied, and the corresponding VO2's were determined. The data at both temperatures demonstrated the biphasic relationship of VO2 to various levels of DO2. A critical level of DO2 (DO2 crit) was defined to reflect the transition area between the dependent and independent portions of the consumption-delivery curve. The average baseline VO2's on the delivery independent portion of the curve were calculated to be 5.33 and 3.17 ml O2.kg-1.min-1 at 39 and 33 degrees C, respectively (P less than 0.001). The corresponding DO2 crit's were 6.17 and 4.57 ml O2.kg-1.min-1 (P less than 0.05). The oxygen extraction ratios at DO2 crit for each of these temperatures did not differ significantly. We conclude that hypothermia, by lowering baseline VO2, reduces DO2 crit. Hypothermia may therefore reduce or eliminate the anaerobic metabolism and subsequent acidosis that would otherwise occur during normothermia at low levels of DO2.

Animals↗
PubMed1992

[Is ex situ surgery of the liver useful for difficult hepatic resections?].

Five cases of hepatic tumor deemed unresectable by conventional techniques are presented to illustrate the potential benefit offered by complete hepatic vascular exclusion (Pringle maneuver associated with inferior vena cava clamping below and above the liver). The most extensive and difficult liver resections may be achieved, with possible venous reconstruction, if the clamping period is not interrupted. Hepatic vascular exclusion may exceed one hour, up to 85 minutes in this series, with a good liver tolerance, in the absence of preoperative liver dysfunction. The advantages and disadvantages of the ex situ extracorporeal liver resections performed under similar circumstances are discussed. The authors consider that the role of ex situ liver procedures should be very limited.

Adult↗
PubMed1992

Differential adhesion of rat colon carcinoma cells to fibronectin in relation to their tumorigenicity.

We examined the fibronectin-adhesive properties of clones from a rat colonic cell line exhibiting distinct tumorigenicity in a syngeneic host. These cells were originally selected on the basis of differential adhesion to plastic surfaces. The TR cell line, when injected subcutaneously, forms a tumour which grows progressively and gives off metastases, whereas the TS cell line forms a small tumour which regresses within a few weeks. The regression is largely mediated by immunological factors and involves a fibroblastic reaction. REGb, a clone from the TS subline, adhered better to fibronectin or RGDS tetrapeptide than did PROb, a clone from the TR subline. However, there was little binding to the RGD tripeptide with either clone. The degree of adhesion was dependent on time and substrate concentration. After 6 h of incubation, 38% and 55% respectively of PROb and REGb cells bound to plates coated with 10 micrograms/ml fibronectin. Adhesion of both clones to fibronectin was inhibited to various degrees when cells were preincubated with RGDS, GRGDS or GRADSPK peptides, whereas other synthetic peptides such as RGD, GRGD or GRGFSPK were ineffective. Binding experiments using 125I-labelled fibronectin showed 39,000 fibronectin receptor sites on REGb cells but only 17,000 on PROb cells. Flow cytometry analysis using both anti-alpha 5 and anti-beta 1 integrins showed more fibronectin receptor sites on REGb than on PROb cells. Both approaches were in accordance with the higher adhesiveness of the REGb clone to fibronectin.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1992

Liver ischemia for hepatic resection: where is the limit?

BACKGROUND: A consecutive series of 50 patients who submitted to 53 hepatic resections with use of continuous normothermic liver ischemia is reported. METHODS: Portal triad clamping has been used in 28 cases, with associated inferior vena caval clamping above and below the liver (hepatic vascular exclusion) in 25 patients. The size of the tumor required major hepatic resection in 38 cases (71.7%). Malignant tumors (83%) were the most common indication for liver resection. Patients were placed in three groups according to the duration of liver ischemia: group A, less than 30 minutes (9 patients); group B, 30 to 60 minutes (29 patients); and group C, 60 or more (15 patients). RESULTS: No differences in mortality rates (5.7% in the entire series and 0% in group C) and morbidity rate could be shown. No significant difference was found in postoperative liver test results, and no persistent alteration remained thereafter. Liver biopsy at 6 and 12 months after operation did not reveal any chronic damage. Liver capability to regenerate was maintained as documented by postoperative computerized tomography scan or magnetic resonance imaging. CONCLUSIONS: Because interruption of hepatic blood flow in normothermia is safe for at least 60 minutes (up to 85 minutes in this study), vascular clamping is recommended for hazardous liver resections to minimize blood loss, which appears to be the main factor of death and morbidity.

Bilirubin↗
PubMed1992

[Leiomyosarcoma of the inferior vena cava invading into the liver. Complete resection with venous reconstruction].

A case of leiomyosarcoma of the retrohepatic inferior vena cava associated with metastasis in the right liver lobe is reported. Resection included extended right hepatectomy, right nephrectomy, and tumor--containing inferior vena cava resection followed by polytetrafluoroethylene tube reconstruction. A comfortable survival was obtained before multifocal malignant spread led to death 42 months after surgery.

Blood Vessel Prosthesis↗
PubMed1992

[Minimal intestinal preparation before colectomy for cancer. Experience of 189 cases].

189 cases of colectomy for cancer have undergone limited bowel preparation by one or two enemas the day before surgery. The anastomosis has been performed manually with a continuous suture of resorbable material. Hospital mortality is 1.6% for the whole series and limited to 0.5% for elective resections despite the old age of the patients included (70.6 +/- 11 years, with 40.7% more than 75 years). Morbidity rate is 13.9% and of 2.6% for local septic complications. No clinical anastomotic dehiscence was demonstrated. From these results, poor local bowel preparation does not appear to be a risk factor of colectomy for cancer.

Adenocarcinoma↗
PubMed1992

[Is extracorporeal liver surgery useful for difficult hepatic resections?].

Five cases of hepatic tumor deemed unresectable by conventional techniques are presented to illustrate the potential benefit offered by complete hepatic vascular exclusion (Pringle maneuver associated with inferior vena cava clamping below and above the liver). The most extensive and difficult liver resections may be achieved, with possible venous reconstruction, if the clamping period is not interrupted. Hepatic vascular exclusion may exceed one hour, up to 85 minutes in this series, with a good liver tolerance, in the absence of preoperative liver dysfunction. The advantages and disadvantages of the ex situ extracorporeal liver resections performed under similar circumstances are discussed. The authors consider that the role of ex situ liver procedures should be very limited.

Adult↗
PubMed1991

Expression of alkaline phosphatase in murine lymphoma cells.

Alkaline phosphatase (ALP) was secreted and expressed at the cell surface of the lymphoma A/63-2 cell line but not on another clone A/63-1 deriving from a single thymoma (A/63) induced by a wild-type Abelson-Moloney viral complex. The enzyme was heat-sensitive and strongly inhibited by L-p-bromotetramisole and L-homoarginine but not by L-phenylalanine. All these data indicated that this enzyme was most likely identical to the L/B/K ALP isoenzyme. Southern blot analysis showed that neither amplification nor polymorphism were responsible for the high expression of the ALP gene observed in A/63-2 cells. On the opposite, the mRNA transcripts of ALP were only detected in A/63-2 cells indicating that a modulation of the ALP gene transcription occurred which could be due to the insertion of the v-abl gene within or near the 5'-flanking region of the ALP promotor in A/63-2 cells. Butyrate strongly increased both the secretion and the expression of the enzyme on A/63-2 cell surface. This induction was strongly inhibited by cordycepin, an RNA biosynthesis inhibitor, and at a lesser degree by cycloheximide, a translation inhibitor suggesting that butyrate induction occurs both at the transcriptional and the translational level.

Alkaline Phosphatase↗
PubMed1991

[Intra-duodenal development of low choledochal diverticula. Apropos of 2 cases].

Two cases of intraduodenal development of a low choledochal diverticulum were observed during the last ten years. Preoperative diagnosis of this biliary malformation is difficult. Clinical presentation consisted of chronic upper abdominal pain and high gastrointestinal obstruction, without either cholangitis or pancreatitis. In both patients, treatment consisted of resection of the diverticulum and suture of its neck via a transduodenal approach. The post-operative course was uneventful and long-term follow-up (2 and 11 years) is satisfactory, showing that cure has been achieved by means of this simple and radical procedure. This particular biliary anomaly must therefore be distinguished from other diverticula of the common bile duct, because of its clinical presentation, diagnostic approach and treatment required.

Adolescent↗
PubMed1991

[Is ischemia of the liver, lasting longer than an hour, a severity factor in hepatectomies? Apropos of 19 cases].

Nineteen hepatic resections with continuous liver ischemia exceeding one hour (60 to 85 min, m = 68 +/- 8 min) are reported. Surgery was undertaken for 15 malignant tumors, mainly metastatic, and 4 benign tumors. In 16 out of 19 cases, a major hepatic resection was necessary to remove massive and central lesions. Vascular clamping was a Pringle maneuver (9 cases), associated with inferior vena cava clamping-complete hepatic vascular exclusion (10 cases). 2050 +/- 2000 ml of packed red cells were infused peroperatively. No operative nor hospital mortality was recorded. Major complications developed in 6 patients: 3 intraperitoneal haemorrhages leading to complementary hemostasis of the raw surface of the liver in the first 24 hours, 1 erosive gastritis, 2 subphrenic abscesses treated by percutaneous drainage. Severe liver failure developed after left trisegmentectomy on a steatotic liver and led to emergency transplantation on the 17th day with success. Except this case, biochemical liver tests demonstrated slight and transitory alteration. Magnetic resonance imaging confirmed the rapidity of the regenerative process and liver biopsies at 6 and 12 months did not show any late changes. There is no relation between the duration of liver ischemia in the limits of this study and post operative morbidity rate, which is more influenced by the magnitude of the resection and the quality of the liver remnant.

Adult↗
PubMed1991

Penetrating carotid injuries--a wartime experience.

Thirty-nine patients with penetrating carotid injuries were treated between 1975 and 1987. All were war victims. On admission 27 (69%) had no neurologic deficit (group I), 8 (20.5%) had a mild neurologic deficit (group II), and 4 (10.5%) had a severe deficit (group III). Repair was undertaken in 38 of 39 (97.5%) patients, and carotid ligation was performed in 1 case (2.5%). Associated injuries were found in 25 (65%) patients. All patients survived. At the time of discharge all group I and II patients had a normal neurologic examination. One patient in group III recovered completely, whereas two had significant improvement. One patient remained unchanged. We conclude that repair should be attempted in all patients with carotid injuries who are seen early (less than 120 minutes) after the accident.

Adolescent↗
PubMed1990

Repeat hepatic resection for primary and metastatic carcinoma of the liver.

During the last 15 years, 19 patients underwent repeated hepatic resections for malignant lesions of the liver. The first hepatic resection had been performed four to 40 months earlier for treatment of hepatocellular carcinoma (nine patients) or hepatic metastases (ten patients), eight of which were of colorectal origin. Repeat resection was an extensive hepatectomy in six, a segmentectomy in six and a local excision in seven. In one patient, three wedge resections and, finally, hepatic transplantation were subsequently performed after an initial extended right lobectomy. The operative mortality rate was 5.2 per cent. The three year actuarial survival rate was 64 per cent after the second resection.

Adult↗
PubMed1989

Differences in glycosylation state of fibronectin from two rat colon carcinoma cell lines in relation to tumoral progressiveness.

We have investigated the biosynthesis and carbohydrate structure of fibronectin secreted by two rat colon carcinoma cell lines. The cell line Prob yields progressive tumors after s.c. injection in syngeneic BD IX rats while tumors developed by Regb cells disappear after 20 days. No difference was observed in the fibronectin biosynthesis from both cell lines; however, the glycosylation degree was higher in Regb than in Prob cells indicating probable differences in the posttransductional process. The analysis of the glycosylation nature shows that fibronectin doesn't bear O-linked carbohydrate chains. The fibronectin of progressive Prob cells is more sialylated than that of the regressive Regb ones. In addition, the tri- and tetraantennary glycans are more important in Prob, while the fucosylated triantennary glycans are three times higher in Regb cells. These differences in the glycosylation state of the fibronectins could explain their differential susceptibility to the proteases treatment. In fact, the low glycosylated fibronectin from the progressive Prob cells was more rapidly degraded by several proteases than that of regressive Regb cells. The identification of the specific sites of proteolytic cleavage by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the cell attachment domain as well as the collagen binding domain of Regb cell fibronectin are particularly protected against proteolytic degradation.

Adenocarcinoma↗
PubMed1989

Endothelial cell growth regulation by PGE1 analog misoprostol and indomethacin.

The role of prostaglandins on growth regulation of different cell types was investigated. We studied the effect of exogenous misoprostol in the presence or absence of indomethacin on the cell growth kinetics. Our results clearly show that misoprostol strongly inhibited the growth of several cancer cells but only slightly affected that of endothelial cells. Moreover, indomethacin alone (which decreases PG synthesis) had little effect on DNA synthesis in endothelial cells or C6 cells but inhibited colonic cancer cells. Conversely, misoprostol stimulated DNA synthesis in endothelial or C6 cells preincubated with indomethacin. This phenomenon was not observed with colonic cancer cells. The role of NSAIDs in the field of cytoprotection is discussed.

Alprostadil↗