Biomedical subjects

G Mentha

Publications and source records attributed to G Mentha.

At least 55 records · Page 3Linked to original sources

PubMed1999

Management of focal nodular hyperplasia and hepatocellular adenoma.

Hepatocellular adenoma and focal nodular hyperplasia are two benign hepatic tumors which are mainly detected in healthy young women. Hepatocellular adenoma is an indication for surgery due to the risk of haemorrhage and malignant transformation. By contrast, focal nodular hyperplasia should be managed conservatively. However, precise diagnosis of these benign liver tumors remains difficult and sometimes impossible, despite new imaging techniques. Because of the risk of diagnostic error, resection or large biopsies of presumed liver tumors should be performed in young women (and a fortiori in men and older patients in whom focal nodular hyperplasia is less prevalent) when the diagnosis of focal nodular hyperplasia is not firmly established. The risk of liver surgery in young patients with normal liver parenchyma is, in the opinion of the authors, lower than the risk of a mistaken diagnosis.

Adenoma, Liver Cell↗

PubMed1999

Management of bleeding pseudoaneurysms in patients with pancreatitis.

BACKGROUND: Bleeding pseudoaneurysm is a rare but frequently fatal complication in patients with pancreatitis. METHOD: The medical records of ten patients who presented to this institution with a bleeding pseudoaneurysm between 1978 and 1997 were reviewed retrospectively. Six patients had chronic pancreatitis and four had acute pancreatitis. The splenic artery was involved in six cases, a pancreaticoduodenal artery in two, the gastroduodenal artery in one and the cystic artery in one. RESULTS: Computed tomography (CT) revealed the bleeding pseudoaneurysm in all patients (n = 6) with chronic pancreatitis but in only one of three with acute pancreatitis. Arteriography always gave the correct diagnosis. Seven patients underwent pancreatic resection as an emergency (n = 3) or within 48 h (n = 4), and survived. Three patients presenting with acute pancreatitis and massive bleeding underwent transcatheter arterial embolization. Two of them had a favourable outcome and one died from a recurrent haemorrhage 7 days later. Overall, two patients suffered significant perioperative complications and one died. CONCLUSION: CT is accurate in the diagnosis of pseudoaneurysms complicating pseudocysts. Primary resection of the pseudoaneurysm, which frequently requires pancreatic resection, is the treatment of choice. Angiography followed by transcatheter embolization is effective, but should be rapidly followed by operation.

Abdominal Pain↗

PubMed1999

Decomplementation with cobra venom factor prolongs survival of xenografted islets in a rat to mouse model.

Although the involvement of complement in hyperacute rejection of xenotransplants is well recognized, its role in rejection of devascularized xenografts, such as pancreatic islets, is not completely understood. In this study, we investigated whether complement participates in the immunopathology of xeno-islet transplantation in a concordant rat to mouse model. Rat pancreatic islets were implanted under the kidney capsule of normal and cobra venom factor (CVF)-decomplementized diabetic C57BL/6 mice. Graft survival was monitored by blood glucose levels. Deposition of IgM and C3 on grafted islets in vivo or on isolated islets in vitro (after incubation with normal and decomplementized mouse serum), as well as CD4- and CD8-positive leucocyte infiltration of grafts, was checked by immunohistochemistry. In addition, complement-mediated cytotoxicity on rat islet cells was evaluated by a 3-(4, 5-dimethythiazolyl)-2.5-diphenyl-2H-tetrazolium-bromide (MTT) assay. A significant C3 deposition was found on grafted islets from the first day after transplantation in vivo, as well as on isolated islets after incubation with mouse serum in vitro. By MTT assay, complement-mediated cytotoxicity for islet cells was found. Decomplementation by CVF decreased C3 deposition on either isolated or grafted islets, delayed CD4- and CD8-positive leucocyte infiltration, led to significant inhibition of complement-mediated cytotoxicity for islet cells, and prolonged graft survival (mean survival time 21.3 versus 8.5 days; P<0.01). Our results indicate that decomplementation can prolong the survival time of devascularized xenografts across concordant species. The deposition of complement on transplanted islets may contribute to xenograft rejection by direct cytotoxicity and by promoting leucocyte infiltration.

Animals↗

PubMed1999

Primary hepatic diffuse large B-cell lymphoma in a patient with chronic hepatitis C.

Epidemiological and experimental data suggest that the hepatitis C virus infection might be associated with the development of distinct types of non-Hodgkin's lymphomas. Here, we report a case of a patient with chronic hepatitis C and type II mixed cryoglobulinemia, who developed a primary hepatic non-Hodgkin's B-cell lymphoma. A diffuse, large B-cell lymphoma was diagnosed based on morphological, immunophenotypical and molecular genetic findings. Hepatitis C virus replication, as evaluated by strand-specific reverse transcriptase-polymerase chain reaction, was detected in the nonneoplastic liver, but not in the lymphomatous tissue. High grade non-Hodgkin's lymphomas, although rare complications, have to be considered as part of the spectrum of hepatitis C virus-related hepatic lesions.

Cryoglobulinemia↗

PubMed1999

Management of true aneurysms of the pancreaticoduodenal arteries.

OBJECTIVE: To review the authors' recent experience and that of the literature since 1973 and to provide management guidelines for true aneurysms of the pancreaticoduodenal arteries (PDA). SUMMARY BACKGROUND DATA: True aneurysms of the PDA are rare, with a total of only 52 cases reported since 1973. METHODS: Six patients were admitted to the authors' institution between 1985 and 1995 for rupture of a true aneurysm of the PDA. They were analyzed with regard to the mode of presentation, preoperative workup, management, and outcome. RESULTS: All patients had severe epigastric pain from retroperitoneal hemorrhage. Computed tomography scanning and angiography were performed in all cases. Aneurysms ranged from 0.7 to 1.2 cm (median 0.9 cm). The celiac axis was stenotic or occluded in five cases. Three patients underwent emergency pancreatoduodenectomy. Two of them survived. In one case, section of the median arcuate ligament was associated with the procedure, and the patient died from an aortic dissection. Embolization was performed in the last three patients. The procedure was definitive in two cases. In one, hemorrhage recurred 8 days later and required surgical ligation of the bleeding artery. CONCLUSIONS: The authors recommend rapid treatment of all true aneurysms of the PDA. Because most of these aneurysms result from a stenosis of the celiac axis, selective embolization may help to preserve patency of the PDA and should, therefore, be the primary therapeutic choice in ruptured aneurysms. Close follow-up is mandatory because of possible recurrent bleeding. Appropriate and expeditious management of true PDA aneurysms should help reduce the mortality rate.

Aged↗

PubMed1999

Expression of alpha-1 proteinase inhibitor in human islet microvascular endothelial cells.

There is a microcirculation system within the islets of Langerhans. However, little is known about the phenotypic and functional characterization of islet microvascular endothelial cells (MVEC). In this study, we purified MVEC from human pancreatic islets by using Ulex europaeus (Sigma, St. Louis, MO) agglutinin-1 (UEA-1)-coated dynabeads (Dynal A.S., Oslo, Norway). These purified human islet MVEC (HI-MVEC) express von Willebrand factor, take up high levels of acetylated LDL, and upregulate endothelial cell leukocyte adhesion molecule 1 in response to tumor necrosis factor-alpha. Ultrastructure examination shows the presence of microvilli and fenestrations on the cell surface, Weibel-Palade bodies in the cytoplasm, and tight junctions between cells. Furthermore, we show that vascular endothelial cell growth factor contributes to the formation of surface fenestrations on cultured HI-MVEC. After purification, HI-MVEC exhibit a very low proliferation capacity and are strongly resistant to trypsin, compared with other original MVEC. We also demonstrate that alpha-1 proteinase inhibitor (Api) is expressed on HI-MVEC and specifically located at the area of cell-cell junctions. By reverse transcription-polymerase chain reaction, a significant messenger RNA band of Api was found only in HI-MVEC, but not in other organ-derived MVEC, indicating that expression of Api is islet MVEC specific. Antibodies to Api significantly reversed the resistance to trypsin and promoted proliferation of HI-MVEC, suggesting that these specific functional characteristics of HI-MVEC are related to the expression of Api. These results indicate that HI-MVEC exhibit some specific morphological and functional characteristics that differ from MVEC derived from other organs.

Antibody Specificity↗

PubMed1998

[Hemosuccus pancreaticus: a rare cause of upper gastrointestinal hemorrhage].

We report on a patient with alcoholic chronic pancreatitis and intermittent upper gastrointestinal haemorrhage. Old blood was seen in the duodenum but no bleeding source could be identified by endoscopy. Computed tomography scanner and angiography disclosed an arterial pseudoaneurysm of the pancreatic tail, and left splenopancreatectomy was performed. In cases of upper gastrointestinal haemorrhage, the pancreas should be considered as a bleeding source if endoscopies remain negative and the patient presents with chronic pancreatitis.

Aneurysm, False↗

PubMed1998

[Long-term follow-up of 9 islets of Langerhans autografts after resection of the pancreas].

INTRODUCTION: Preservation of physiological endocrine pancreatic function represents a major problem in pancreatectomised patients. In 40 to 100%, pancreatic resection can result in diabetes, which is often difficult to manage. Islet autotransplantation has been proposed to prevent this severe metabolic consequence. PATIENTS AND METHODS: Between March 1992 and January 1997 we performed 9 human islet autotransplantations in Geneva. The patients comprised 6 males and 3 females aged 40 to 81 years (median: 51 years). The pancreatectomy was total in 3 cases, subtotal (95%) in 2 cases and partial (40-80%) in the others. Indications for resection were alcohol-induced chronic pancreatitis (6 cases) and focal benign pancreatic pathologies (3 cases). After collagenase digestion, unpurified islets were injected intraportally and embolised into the liver. Patient metabolic status was regularly tested by 24-hour serum glucose profile, measurement of glycosylated haemoglobin, oral and intravenous glucose tolerance tests and glucagon stimulation test. RESULTS: Immediately after autotransplantation, one patient had persistent insulin-dependent diabetes. Among the 8 patients who were insulin-independent soon after the graft, 4 presented a progressive deterioration of endocrine pancreatic function and required insulin therapy 5, 8, 24 and 36 months after the graft. Currently, 4 patients are insulin-independent: three of them have normal glucose tolerance tests (24, and 48 months after the graft) and the last presented with glucose intolerance 22 months after the graft but still does not require exogenous insulin. CONCLUSION: Islet autotransplantation can be considered a useful therapeutic option serving to prevent or delay the occurrence of surgically-induced diabetes. In our opinion, islet autotransplantation should be offered to any non diabetic patient needing to undergo major pancreatic resection.

Adult↗

PubMed1998

[Isolation of the pig islets of Langerhans: evaluation of in vitro and in vivo function].

Pig islets are considered the best alternative to human islets in the treatment of insulin-dependent diabetes. Pigs could represent a potential islet donor for xenotransplantation in humans because of the close similarity between human and porcine insulin and the theoretically unlimited availability of porcine pancreas. From November 1991 to January 1997 we performed 221 pig islet isolations from 3 pig sources: group 1: minipigs (age 9-18 months) and white pigs (3-8 months), group 2: large white pigs (5-8 months), group 3: large white pigs (12-24 months). Islets were isolated according to a semi-automated method using enzymatic digestion and purification through discontinuous Euro-Ficoll gradients. The pancreases were surgically removed in our laboratory for group 1, while pancreases from groups 2 and 3 were removed at the slaughterhouse with an average warm ischemia time of 15 minutes. In vitro islet function was assessed by static incubations and perifusions, and in vivo islet function by transplantation under the kidney capsule of nude diabetic mice. The results were as follows: [table: see text] Insulin secretion increased twofold after in vitro glucose stimulation. We obtained restoration of euglycemia in diabetic mice which survived > 3 months after the graft and returned to diabetes after nephrectomy. This study shows that our isolated pig islets are viable and functional in vitro and in vivo after transplantation.

Animals↗

PubMed1998

[Pancreatic pseudocysts: choice of treatment?].

Pseudocysts of the pancreas may require drainage or resection during their evolution. External drainage can be considered as a treatment of first resort with low related morbidity. It also offers a means of treating patients with major contraindications for surgery. In our experience, however, only 55% of external drainages prove successful. Therefore, surgical treatment, even at the cost of low-rate morbidity, remains the only final treatment for complications linked to pseudocysts of the pancreas. In the long term, however, these results depend on the etiology of the pseudocysts.

Adult↗

PubMed1998

Inhibition of leukocyte adherence and transendothelial migration in cultured human liver vascular endothelial cells by prostaglandin E1.

Primary graft dysfunction is a major complication of orthotopic liver transplantation, and hepatic ischemic reperfusion injury is considered to be its major determinant cause. Although oxygen free radicals play an important role, leukocytes, cytokines, and adhesion molecules also contribute to hepatic ischemic reperfusion injury. Prostaglandin E1 (PGE1) has been shown to protect against impairment and dysfunction of transplanted livers in various experimental models as well as in clinical liver transplantation. In this study, the role of PGE1 on leukocyte adherence and transendothelial migration was investigated in cultured human liver vascular endothelial cells (HLVEC). Our results indicated that stimulated, but not resting, leukocytes exhibited high adhesion and transmigration capacity. HLVEC incubated with tumor necrosis factor (TNF) promoted leukocyte adherence and transendothelial migration. PGE1 inhibited leukocyte adherence to HLVEC when it was preincubated with either HLVEC or leukocytes. Moreover, PGE1 also suppressed stimulated leukocyte transendothelial migration in a dose-dependent manner. The inhibitory activity of PGE1 was further investigated on both HLVEC and leukocytes with attention to adhesion molecules. On HLVEC, PGE1 down-regulated TNF-induced expression of endothelial cell leukocyte adhesion molecule 1 and vascular adhesion molecule 1, but not intercellular adhesion molecule 1. On leukocytes, PGE1 inhibited expression of CD11a/CD18 and membrane-bound TNF on PHA-stimulated leukocytes. PGE1 also suppressed TNF release from the stimulated leukocytes. These results indicated that inhibition of leukocyte adherence and transendothelial migration is one of the mechanisms by which PGE1 protects liver grafts.

Alprostadil↗

PubMed1998

Partial hepatectomy or orthotopic liver transplantation for the treatment of resectable hepatocellular carcinoma? A cost-effectiveness perspective.

The treatment of patients with compensated liver cirrhosis and small hepatocarcinomas remains controversial. Whereas partial hepatectomy (PH) is currently recommended, the role of orthotopic liver transplantation (OLT) has become progressively accepted. We used the techniques of decision analysis to measure the clinical benefits and the economic consequences of immediate resection versus transplantation in patients with compensated cirrhosis and who were diagnosed with small hepatocellular carcinoma (HCC). We restricted our analysis to patients with resectable carcinomas, which is either solitary tumor (< or = 5 cm in diameter), or multiple tumors (up to 3), none being > 3 cm in diameter and, in both cases, no tumor invasion of blood vessels. We took into account the risks of tumor spreading and dissemination and/or development of decompensated cirrhosis while waiting for donor organs because organ shortage is presented as the main obstacle to transplantation in these patients. Our analysis suggests that orthotopic liver transplantation (OLT) offers a substantial survival benefit compared with resection, ranging from a minimum of 1 year to a maximum of 4.7 years depending on treatment-related survival rates. However, the magnitude of this benefit relies on the availability of an organ donor; therefore, if the waiting period exceeds 6 to 10 months, depending on tumor growth pattern, the increase in life expectancy provided by transplantation is overwhelmed by the risks that patients face while waiting for transplantation. Consequently, partial resection becomes the preferred strategy. The predicted marginal cost-effectiveness ratios of transplantation compared with resection would range between $44,454 and $183,840 per additional year gained mainly influenced by the time delay before getting a transplant. We conclude that compared with partial hepatectomy (PH), OLT for resectable hepatocarcinoma(s) offers substantial survival benefit among well-targeted subgroups of patients as long as an organ donor is available within a maximal 6 to 10 months time delay, which is a plausible scenario in most centers with a liver transplant program. However, the marginal cost-effectiveness ratios incurred by this strategy are higher than that of many other current medical interventions.

Carcinoma, Hepatocellular↗

PubMed1998

Blunt abdominal trauma in adults: role of CT in the diagnosis and management of visceral injuries. Part 1: liver and spleen.

Computed tomography is now widely used in the initial diagnostic workup of adult trauma victims with suspected intra-abdominal injuries. We review the role of CT in the detection and management of blunt visceral injuries in two parts. In the first part we discuss general aspects of performing CT in the setting of abdominal trauma and the diagnostic findings of intra-abdominal hemorrhage and blunt hepatic and splenic injuries. Hepatic and splenic injuries can be detected by means of CT with a high accuracy. The vast majority of hepatic injuries can be successfully managed conservatively, even when CT demonstrates parenchymal damage of more than three segments and major hemoperitoneum. Delayed complications, e. g., formation of biloma or a false aneurysm, can be readily detected on repeat CT studies, although they are quite uncommon. The outcome of conservative treatment of splenic injuries remains unpredictable because delayed splenic rupture may occur even when initial CT shows only minor parenchymal lesions and little or no intraperitoneal hemorrhage.

Abdominal Injuries↗

PubMed1998

Blunt abdominal trauma in adults: role of CT in the diagnosis and management of visceral injuries. Part 2: Gastrointestinal tract and retroperitoneal organs.

Computed tomography plays an important role in the detection and management of blunt visceral injuries in adults. Current standard examination techniques enable detection of the majority of perforating or devascularizing bowel injuries, although diagnostic findings are often subtle and meticulous inspection is required. Computed tomography may demonstrate pancreatic contusions and lacerations and help in distinguishing minor traumatic lesions without involvement of the pancreatic duct (organ injury scale, grades I and II) from deep lacerations with ductal involvement (grades III and V). Computed tomography enables distinguishing renal contusions and minor cortical lacerations that can usually be managed conservatively (injuries of grades I-III) from corticomedullary lacerations and injuries of the major renal vessels (grades IV and V) that have a less favorable prognosis and more commonly require surgical repair. In addition, CT is well suited for the detection of active renal hemorrhage and guidance of transcatheter embolization treatment and delineation of preexisting benign or malignant pathologies that may predispose to posttraumatic hemorrhage. The radiologist's awareness of the diagnostic CT findings of abdominal visceral injuries as well as their clinical and surgical implications are important prerequisites for optimal patient management.

Abdominal Injuries↗

PubMed1998

Persistence of the intestinal defect in abetalipoproteinaemia after liver transplantation.

A 16-year-old girl is described with abetalipoproteinaemia who underwent liver transplantation for hepatic cirrhosis. After this procedure her serum lipoprotein profile was corrected; however, fat malabsorption and steatorrhea persisted because the primary defect, a mutant microsomal triglyceride-transfer protein, remains expressed in the intestine.

Abetalipoproteinemia↗

PubMed1998

Management of true aneurysms of the splenic artery.

BACKGROUND: Splenic artery aneurysms (SAA) are detected with increasing frequency but their management still remains controversial. This paper relates our experience in the outcome and management of ruptured aneurysms of the splenic artery. METHODS: Between 1977 and 1996, 8 patients presented to our institution with a ruptured SAA. Their ages ranged from 25 to 72 years (mean 55 ys). RESULTS: All patients presented with rupture as the first sign of SAA. One patient was at 32 weeks of gestation and rupture suggested placental abruption. Three patients required cardiopulmonary reanimation prior to surgical procedures. Splenopancreatectomy (n = 4), splenectomy (n = 2), and ligation of the splenic artery (n = 1) were performed. Seven of the 8 patients survived. Size of aneurysms ranged from 2 cm to 3.5 cm (mean 3 cm). CONCLUSIONS: SAA may rupture at any age. Diagnosis during pregnancy rests upon a high index of suspicion. The mortality rate remains low if immediate resuscitation is performed and an aggressive surgical approach is taken.

Adult↗

PubMed1998

Detection of intrahepatic hepatitis C virus replication by strand-specific semi-quantitative RT-PCR: preliminary application to the liver transplantation model.

BACKGROUND/AIMS: Although the hepatitis C virus infection recurs in virtually all patients after liver transplantation, up to 50% of patients may not have histological recurrent hepatitis 1 year after liver transplantation. To study the relationship between hepatitis C virus infection and liver disease after liver transplantation, we compared the intrahepatic hepatitis C virus replication levels with the liver histopathology among liver transplant recipients. METHODS: The intrahepatic negative-strand HCV RNA (i.e. the putative hepatitis C virus replication intermediate RNA) was evaluated by a semi-quantitative, strand-specific reverse transcriptase-polymerase chain reaction in 44 liver specimens from 23 patients with hepatitis C virus reinfection after liver transplantation. Results were compared with the time from liver transplantation, presence, grading and staging of the recurrent hepatitis, amount of hepatitis C virus antigens in the liver and serum HCV RNA levels. RESULTS: Negative-strand HCV RNA was detected in 42 liver specimens as early as 7 days after liver transplantation. Its titers correlated with the amount of intrahepatic hepatitis C virus antigens, but not with HCV RNA levels in serum. Levels of negative-strand HCV RNA in 19 specimens without hepatitis were comparable to those seen in 25 specimens with hepatitis (p=0.492), and were unrelated to the liver disease grading and staging scores. The intrahepatic hepatitis C virus replication could occasionally precede the recurrence of the hepatitis by several months. CONCLUSIONS: Molecular evidence has been obtained for intrahepatic hepatitis C virus replication occurring early after liver transplantation. The level of replication is not correlated with the development of recurrent hepatitis, suggesting that hepatitis C virus may replicate without inducing morphological evidence of liver damage.

Adult↗

PubMed1998

Hepatitis G virus infection among liver graft recipients: anatomoclinical correlations.

Hepatitis G virus (HGV) causes persistent infection in man, but its disease association is controversial. We studied the HGV disease association in 25 liver transplantation (LT) recipients without evidence of hepatitis B and C infection. HGV RNA was tested by semiquantitative RT-PCR in serial serum samples and its presence was correlated with the biochemical and histological evidence of liver damage. The overall prevalence of HGV infection in this population was 9/25 (36%), one patient being HGV RNA positive since before LT, while the other eight apparently acquired de novo infections after LT. In five cases, appearance of HGV was followed by biochemical and histological evidence of liver damage: the liver biopsy showed acute rejection in two cases, acute cholangitis in two, and acute hepatitis in one. At the end of follow-up, histological evidence of chronic hepatitis was found in one HGV-positive patient but also in three HGV-negative patients, whereas the only patient with acute hepatitis at the time HGV RNA was first detected in serum developed an intralobular gigantocellular granuloma. In conclusion, HGV infection after LT may be seldom associated with acute and chronic liver damage, but comparable histological features can be observed also among HGV-negative controls.

Adolescent↗