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Biomedical subjects

V Mazzaferro

Publications and source records attributed to V Mazzaferro.

At least 73 records · Page 4Linked to original sources
PubMed1990

The hepatotropic influence of cyclosporine.

The effect of cyclosporine on liver regeneration has been investigated in 25 dogs that underwent an end-to-side portacaval shunt (Eck fistula) followed by 4 days continuous infusion of the drug into the left branch of the portal vein. Three different cyclosporine infusion rates were used: 0.06, 0.6, and 4.0 mg/kg/day. Control animals received the intravenous vehicle of cyclosporine at the same rate as the treated animals; a second control group received insulin, 0.42 units/kg/day. Hepatocyte 3H-thymidine-labeled mitoses (index of hyperplasia) and hepatocyte volume (index of hypertrophy) were studied in the left (infused) and right (control) lobes in each animal. Cyclosporine vehicle had no measurable effect on hepatocytes that suffered typical atrophy and moderate increase in mitotic index after the Eck fistula. Cyclosporine infusion stimulated cell renewal significantly and restored hepatocyte size in the infused lobes with a dose-response relation. Similar positive effects were observed in the right (nonperfused) lobes, although they were less than those in the left (infused) lobes. This was because of an unmistakable spillover of cyclosporine from the infused lobes, especially in the large-dose group. No sign of hepatotoxicity was detected at any cyclosporine infusion rate. Cyclosporine has a remarkable hepatotropic effect that may be helpful in the context of liver transplantation.

Animals↗
PubMed1989

Efficacy of liver transplantation in patients with primary biliary cirrhosis.

No controlled trials have been performed to assess the efficacy of liver transplantation. Because of the marked improvement in survival after liver transplantation since 1981, random assignment of patients to a control group not undergoing transplantation is considered clinically inappropriate. To assess the efficacy of liver transplantation in patients with primary biliary cirrhosis, we compared survival in 161 patients with this diagnosis who had undergone a liver transplantation with survival in patients with the same diagnosis who had been treated conservatively. The comparison was performed with use of a recently developed statistical technique, the Mayo model. All patients had undergone liver transplantation between March 1980 and June 1987 and were followed for a median of 25 months. Three months after liver transplantation, the Kaplan-Meier survival probabilities in the recipients were substantially higher than the Mayo-model "simulated-control" survival probabilities (P less than 0.001). At two years, the Kaplan-Meier survival probability was 0.74, whereas the mean Mayo-model survival probability was 0.31. The patients who were at low risk according to the Mayo model had the best probability of survival after liver transplantation; however, patients at all risk levels who had undergone liver transplantation had higher probabilities of survival that those who had not. We conclude that liver transplantation is an efficacious treatment in patients with advanced primary biliary cirrhosis.

Follow-Up Studies↗
PubMed1989

The effect of estrogen and tamoxifen on hepatocyte proliferation in vivo and in vitro.

We have previously shown that changes in estrogen-hepatocyte interaction occur during liver regeneration. Following 70% hepatectomy, estrogen levels in the blood were elevated, the number of estrogen receptors in the liver was increased and there was an active translocation of estrogen receptors from the cytosol to the nucleus. The injection of tamoxifen, an estrogen antagonist, inhibits hepatocyte proliferation following partial hepatectomy. The administration of 1 microgram tamoxifen per gm body weight at zero time or 6 hr after the operation resulted in a significant inhibition both of DNA synthesis and of the number of cells in mitosis. Injections of tamoxifen 12 hr or later after the operation had no effect. Concomitant injections of equimolar amounts of estrogen abolished the inhibition by tamoxifen. The effects of estrogen and tamoxifen were also tested on hepatocytes in primary culture. Estrogens in the presence of 5% normal rat serum stimulated hepatocyte DNA synthesis as determined by [3H]thymidine incorporation and the labeling index, whereas epidermal growth factor-induced DNA synthesis in the absence of normal rat serum was strongly inhibited. Tamoxifen, in contrast, inhibited DNA synthesis of hepatocytes in the presence of 5% normal rat serum and reversed the stimulatory effect of estrogen in the same system. Attempts to elucidate the mechanism of tamoxifen inhibition in vitro indicated that one effect of tamoxifen is to prevent the amiloride-sensitive Na+ influx necessary to initiate hepatocyte proliferation.

Animals↗
PubMed1989

Reappraisal of surgical treatment of small hepatocellular carcinomas in cirrhosis: clinicopathological study of resection or transplantation.

Thirty-two patients with hepatocellular carcinoma (HCC) occurring in individuals with cirrhosis had a potentially curative surgical procedure. Twenty-two had segmental hepatic resections (HR), and 10 underwent orthotopic liver transplantation (OLTx). The diagnosis of hepatic malignancy was established in each case preoperatively, and each case was studied intraoperatively by means of sonography. Postoperatively each surgical specimen was examined pathologically with attention to the possibility of intrahepatic tumor spread. Twenty-three of the 32 patients had single small HCC lesion (less than 5 cm diameter) identified preoperatively. Sixteen of these underwent HR and seven underwent OLTx. Multiple additional neoplastic lesions were found in 19% of the 16 HR cases and in 14% of those undergoing OLTx when the resection specimens were examined pathologically. Vascular invasion was present in 43% of the OLTx patients and in 25% of the HR patients. Subtotal hepatic resection for small HCC occurring in cirrhosis has produced few long-term survivals. Both pre- and intraoperative sonography have been shown to underestimate the extent and distribution of these tumors. Based upon this experience that (1) vascular spread occurs often in HCC and (2) a high risk of postoperative hepatic failure can be expected after HR in cirrhotic individuals, OLTx is the most rational surgical procedure for such cases as it has the potential to cure.

Carcinoma, Hepatocellular↗
PubMed1989

Estradiol and testosterone levels in patients undergoing partial hepatectomy. A possible signal for hepatic regeneration?

In five adult male patients undergoing a 40-60% partial hepatectomy, serum sex hormone levels before and after hepatic resection were determined. Blood was drawn immediately prior to each surgical procedure and at specified time points postoperatively. Compared to hormone levels found prior to surgery, following major hepatic resection, estradiol levels increase at 24 and 48 hr, while testosterone levels decline, being significantly reduced at 96 and 144 hr. These data demonstrate that adult males who undergo a 40-60% partial hepatectomy experience alterations in their sex hormone levels similar to those observed in male rats following a 70% hepatectomy. These changes in sex hormone levels have been associated in animals with an alteration of the sex hormone receptor status of the liver that is thought to participate in the initiation of the regenerative response. These studies suggest, but do not prove, that in man, as in the case of the rat, sex hormones may participate in the initiation of or at least modulate in part the regenerative response that occurs following a major hepatic resection.

Adult↗
PubMed1989

Pharmacologic modulation of experimental postischemic hepatic function.

The present study evaluated and compared the effects of SRI 63-441, a potent platelet activating factor antagonist, superoxide dismutase (SOD), an oxygen free radical scavenger, and ibuprofen, a cyclooxygenase inhibitor on hepatic function after 90 minutes of warm ischemia. After warm ischemia, livers were harvested and underwent 90 minutes of warm, oxygenated, sanguinous perfusion on an isolated liver perfusion apparatus. Pretreatment of donor animals with 20 mg/kg intravenous (I.V.) SRI 63-441 5 minutes before induction of total hepatic ischemia resulted in significantly increased bile production, a significant decrease in transaminase release, and a higher tissue adenosine triphosphate (ATP) content when compared with ischemic nontreated controls. SOD resulted in improved bile production and decreased transaminase liberation only when present in the perfusate at the time of in vitro reperfusion. Ibuprofen did not improve postischemic hepatic function in this model. Electron microscopy revealed patchy hepatocellular vacuolization with an intact sinusoidal endothelium in all ischemic livers. However, the degree of damage was less severe in the livers from those rats pretreated with 20 mg/kg SRI 63-441. This study demonstrates that SRI 63-441 pretreatment significantly reduces hepatic warm ischemic injury, and in the present model, appears superior to two other agents that have been advanced in the treatment of ischemic injury. The use of such agents singly or in combinations have important implications as regards gaining a better understanding of the basic mechanisms in organ ischemia, and moreover, for therapeutic applications in organ ischemia and preservation.

Animals↗
PubMed1989

Hepatic artery thrombosis after pediatric liver transplantation--a medical or surgical event?

Hepatic artery thrombosis (HAT) is one of the most serious complications after orthotopic liver transplantation, and is associated with a high morbidity and mortality. This study retrospectively reviewed 66 liver transplants in children under the age of 10 years during a year-long period at a single institution. A total of 28 perioperative variables were analyzed to identify responsible factors of HAT. Of the 66 children, 18 (26%) developed HAT within 15 days after the transplant (HAT group); 29 (42%) had an uneventful postoperative course (control group). To avoid the possible influence of other complications 19 patients were excluded. Of the variables compared between the 2 study groups, three surgical factors (diameter of the hepatic artery--greater or less than 3 mm; type of arterial anastomosis--end-to-end versus the use of an iliac graft or aortic conduit; and number of times the anastomosis was redone--one versus more than one), were found to be significantly different (P less than .05) between HAT and control groups. Two medical factors also were significantly different: the use of intraoperative transfusion of fresh frozen plasma (FFP) and the administration of postoperative prophylactic anticoagulant treatment. A heparin and dextran-40 protocol appeared to be effective in preventing HAT (P less than .02). Moreover, after multivariate analysis, anticoagulation therapy was demonstrated to be the major independent variable influencing HAT. A better definition of factors responsible for the occurrence of HAT is required. This study should help in formulating effective methods to decrease the incidence of this dreaded complication after liver transplantation.

Anastomosis, Surgical↗
PubMed1989

A modified technique of orthotopic transplant of the kidney in rabbits.

In this study kidneys were harvested from bred-for-research cats weighing 4 to 5 kg. General principles of donor bilateral nephrectomy en bloc with aorta, vena cava, renal vessels, and ureters were followed. After the harvest the grafts were placed in lactated Ringer slush. A cuff was prepared on the renal vein over a 10 French plastic tube. The aorta was divided and left in connection with the renal artery at each side. Twenty female checkered Flemish giant rabbits weighing 4.0-6.0 kg served as recipients. After premedication with 40 mg/kg of ketamine, anesthesia was maintained with repeated doses (every 10-15 min) of a 0.1-mL mixture of 5 parts ketamine and 1 part acepromazine diluted 50% in a normal saline. Arterial pressure, CVP, blood gases, and temperature were monitored. Through a limited midline incision a native left nephrectomy was performed. The venous anastomosis was performed with a cuff technique without clamping the vena cava (which causes severe hemodynamic instability); the anastomotic time was 2-3 min. The arterial anastomosis was performed with an end-to-side aorta-to-aorta anastomosis; the anastomotic time was 5 to 7 min. There were no episodes of venous or arterial thrombosis. The donor procedure took approximately 40 min, and the backtable preparation of the graft an additional 45 to 60 min. Preparation of the recipient for the anastomosis took 15 min and the anastomotic time (warm ischemia) was 13 +/- 5 min. In this model suitable for xenograft research the duration of the surgery in the recipient has been greatly reduced because of (1) the previous backtable preparation of the graft, and (2) the cuff technique used for venous anastomosis. The present anesthesia regimen and careful hemodynamic monitoring were also important in the success of this model.

Anesthesia, General↗
PubMed1989

Transplantation of the liver for metastatic endocrine tumors of the intestine and pancreas.

In the Pittsburgh series of 1,000 orthotopic liver transplants (OLTx), from January 1981 to July 1987, the indication for transplantation in five patients consisted of unresectable hepatic metastases arising from endocrine tumors of gastrointestinal origin: glucagonoma, two patients; carcinoid, two, and gastrinoma, one patient. Three patients underwent resection of the primary tumor (two distal pancreatectomies and one ileal resection) at the time of the hepatic transplantation. All patients underwent extensive nodal dissection. Three of the five patients are alive with no evidence of residual disease after a median follow-up study of 12 months. Hepatic transplantation broadens the concept of radical excision of tumor and may be considered as a potential therapeutic approach for some highly selected instances of unresectable hepatic metastases arising from endocrine tumors of the intestine and pancreas.

Adenoma, Islet Cell↗
PubMed1988

Chordoma: natural history and treatment results in 33 cases.

Thirty-three chordomas were observed at the Istituto Nazionale Tumori of Milan from 1933 to 1983: 27 sacrococcygeal, 3 spheno-occipital, and 3 vertebral. The male:female ratio was 2.7, and the median age was 63 yr for patients with sacrococcygeal and 35.2 yr for those with nonsacral chordomas. After pathologic reassessment, distinct cytologic patterns were found: physaliphorous, syncytial, and mixed subtypes, with variable degrees of cytologic atypia. However, no evident difference in survival was documented in relation to these cytohistologic features. Four cases had a prior traumatic fracture, and the pathogenetic role of trauma is stressed. Eight cases were operated with adequate surgery and only three recurred, whereas of 11 inadequate operations, 10 developed local relapse. However, follow-up for recent adequate operations is short. Radiation therapy seemed to be effective with adjuvant or palliative aims. No chemotherapeutic regimen achieved any result; one case had a short complete remission after cis-dichlorodiammineplatinum + vinblastine + bleomycin (PVB). This analysis confirms the possibility of achieving radicality with high resection of the sacrum for lesions confined below the second sacral vertebra. Nonsacral chordomas were all unresectable. The best treatment for unresectable lesions seems to be palliative surgery plus radiotherapy.

Adolescent↗
PubMed1988

Renal artery reconstruction for harvesting injuries in kidney transplantation with particular reference to the use of vascular allografts.

At the University of Pittsburgh during the calendar year 1986, an arterial injury occurred during harvesting in 20 (7.5%) of the 270 grafts used to perform kidney transplantation (KTx). Four cases required reconstruction, using extension iliac arterial allografts from cadaveric donors of the same blood type; 6 patients, remodelling of the aortic patch in multiple arteries; 4 cases, repairs for injuries to the smaller segmental/polar arteries; 6 cases, a combination of the above techniques. These ex vivo arterial reconstructions are described and the use of donor arterial homografts is emphasized. No deaths have occurred at an average follow-up of 19 months. The postoperative acute tubular necrosis (ATN) rate was significantly higher (90%) compared with non-reconstructed kidneys during the same year (30%). The 1-year graft survival of kidneys undergoing arterial reconstruction (75%) was statistically no different than the overall kidney-transplant survival. Whenever extension iliac allografts were utilized, the cyclosporin-steroid immunosuppression required to control the kidney rejection contributed to the long-term patency rate of the graft. Since the number of organs available for grafting is limited, reconstruction of injured renal vessels has become justified, allowing valuable kidneys to be used that would otherwise be lost.

Adult↗
PubMed1988

Primary lymphoma of the liver showing immunohistochemical evidence of T-cell origin. Successful management by right trisegmentectomy.

Primary malignant lymphomas of the liver are extremely rare. Thus far, 28 cases (1-13) of this entity have been described, but after careful clinical and histological staging, no other sites of extrahepatic involvement were demonstrated in 17 of these cases (2,3,5-13). We recently had the opportunity to investigate and manage a case of true primary malignant peripheral T-cell lymphoma of the liver in a 22-year-old man. To our knowledge this is the first reported case of a primary T-cell lymphoma of the liver. The patient was successfully treated with a right trisegmentectomy and no tumor recurrence has appeared after five years.

Adult↗
PubMed1988

Kaposi's sarcoma: malignant tumor or proliferative disorder?

UNLABELLED: In order to provide information on the response to treatments and clinico-pathological pattern, the clinical course of 41 patients with classic Kaposi's sarcoma (KS) was reconsidered. Twenty-six cases presented a single nodular lesion, and 15 multiple, pluricentric lesions. Surgery was the first treatment for patients with single lesions, 14 of 26 (54%) patients had recurrences: the disease-free interval ranged from a few months to 11 years. Five cases had disseminated disease, three of these were preceded by local recurrence. Cases with multiple lesions were treated by a combination of surgery, chemo- and radiation therapy (RT). In three cases spontaneous regression of disease was observed and two of these are presently disease-free. After chemotherapy and RT, many patients had complete remission of disseminated disease for up to 40 months. The drugs of first choice were vinblastine and bleomycin. Over all, only one patient died of KS, 10 years after diagnosis, nevertheless the cure rate was very poor and the final overall disease-free rate was around 30%. Proper treatment for nodular or disseminated lesions provides a fair disease-free period. FINAL CONSIDERATIONS: mortality of disease is exceptional despite the 80% risk of recurrence or dissemination. Data from our series do not provide proof that adequate control of the primary single lesion could screen against recurrence: the interval between treatment of the first lesion and recurrence is sometimes exceptionally long, up to more than 10 years, and for that it is not easy to state when disease is really cured. These considerations and other analogies between KS and lymphoproliferative disorders in immunodepressed people strongly suggests the possibility of a non-malignant or even non-tumoral pattern to this disease, with implications for therapeutic strategies.

Adult↗
PubMed1988

Does hyperprolactinemia affect hepatic regeneration independent of sex steroids?

Prolactin, administered exogenously, has been shown to be trophic to the liver, causing increases in the liver weight-to-body weight ratio. In ornithine decarboxylase activity, and in thymidine kinase activity. To investigate the effect of endogenous hyperprolactinemia on hepatic regeneration, pituitary isografts were placed beneath the renal capsule in rats 2 weeks before the rats underwent a two-thirds partial hepatectomy. Prolactin levels 2 weeks after the transplant were greater in the animals with the pituitary isografts compared with levels in controls. The increase in the liver weight-to-body weight ratio after hepatectomy was similar in the rats with pituitary transplant and the controls. However, chronic hyperprolactinemia was associated with increased basal levels of ornithine decarboxylase activity and thymidine kinase activity. Both ornithine decarboxylase activity and thymidine kinase activity increased after partial hepatectomy, and the magnitude of the changes was similar for both groups of animals. The levels of estrogen receptor activity before the partial hepatectomy and the reduction in receptor activity that follows partial hepatectomy were similar in the two groups of animals. Moreover, the levels of androgen receptor activity within the liver before partial hepatectomy and the increase in receptor activity after hepatectomy were similar in the two groups of animals. Thus, chronic sustained hyperprolactinemia has no beneficial effect on the hepatic regenerative response, despite induction of both basal ornithine decarboxylase and thymidine kinase activities.

Animals↗