Treatment of hypercholesterolemia in the Watanabe rabbit using allogeneic hepatocellular transplantation under a regeneration stimulus

Numerous studies have reported successful allotransplantation of hepatocytes. However, none have shown long-term correction of a liver-related metabolic defect. In this study, we used a method of regional hepatocyte transplantation and subsequent induction of transplanted cell proliferation by regeneration response in the transplant-bearing liver lobes. New Zealand White rabbits were used as cell donors and Watanabe heritable hyperlipidemic (WHHL) rabbits were used as cell recipients (2 x 10(8) cells/rabbit). All recipient rabbits were maintained on daily cyclosporine. Two weeks after baseline serum cholesterol determination, group I WHHL rabbits (n = 7) received an infusion of cells into the right lateral liver lobe, and a loose ligature was placed around the portal venous branch supplying the anterior lobe. After 1 week, to allow engraftment, the portal venous branch was ligated, which resulted in the atrophy of the affected liver parenchyma and induction of hyperplasia in the transplant-bearing liver tissue. Group II rabbits (n = 6) were transplanted with New Zealand White hepatocytes without portal branch ligation (PBL) and group III rabbits (n = 4) were subjected to sham transplantation (saline) and PBL. The experimental period extended to 150 days after transplantation. All WHHL rabbits transplanted with normal hepatocytes showed reduction in serum cholesterol and low-density lipoprotein (LDL) levels. Group I (PBL-stimulated) recipients demonstrated a more pronounced and sustained effect than group II animals (P < 0.05). Group III controls showed only a slight, typical for aging decrease in serum cholesterol. Group I recipient livers perfused with LDL labeled with 1,1'-dioctadecyl-3,3,3',3'-tetramethyl indocarbocyanine perchlorate (DiI) showed much higher numbers of DiI-LDL-positive hepatocytes than those of group II recipients. In conclusion, a liver regeneration stimulus enhanced the population of transplanted hepatocytes and their functional effect in a large animal model of inborn error of liver metabolism.

Avoiding complications after laparoscopic esophago-gastric banding: experience with 400 consecutive patients

BACKGROUND

Among bariatric operations, laparoscopic adjustable gastric banding (LAGB) has been the preferred one in Europe and Australia, and has become recently popular in the USA. Like every surgical procedure, however, it is not devoid of specific complications, like slippage, band erosion, outlet obstruction and port problems. Assuming that the absence of the pouch may avoid postoperative slippage, we introduced the technique of esophago-gastric placement, instead of the original gastric banding technique. A further technical variant, introduced in June 2002, consists of suturing the gastric fundus to the left hemidiaphragm, using two non-resorbable sutures and pledgets.

METHODS

Between January 1999 and July 2005, 400 LAGBs have been placed in 90 males and 310 females, with the technical variants above. Mean age was 42 (range 17-69 years), and mean BMI was 44.8 kg/m(2) (range 33-67).

RESULTS

Mean hospital stay was 2.5 days (range 1-17). Mortality has been zero. Major complications included: 16 slippages (after a range of 6-45 months), 5 outlet obstructions (immediately after the operation), and one intragastric migration (after 2 years). Minor complications included 18 port problems. Since the introduction of gastric fundus fixation to the diaphragm in 2002, gastric slippage has decreased from 8% to 0.9%. BMI has decreased from 44.8 to 32 kg/m(2) at 60 months.

CONCLUSIONS

The technique herein presented is effective and useful to prevent postoperative gastric slippage. It does not induce pseudo-achalasia, if strictly controlled. In fact, it is avoided by the patient due to the immediate appearance of dysphagia, in the case of wrong food ingestion. Long-term clinico-radiological follow-up confirms that the technique is safe and effective in motivated patients with good compliance and willing to undergo periodic studies.

Long-Term Insulin Independence following Repeated Islet Transplantation in Totally Pancreatectomized Diabetic Pigs

Clinical islet transplantation (Tx) in type I diabetic patients has been successful so far only in a minority of cases, probably because of multiple factors, partly immunologic and partly nonimmunologic in nature. Pre-clinical studies of islet Tx in large animals are still needed to clarify the reasons and find possible solutions. In this study, we tested the feasibility of noninvasive, repeated intrahepatic allo-Tx of porcine pancreatic islets obtained from multiple donors, in pigs rendered diabetic by total pancreatectomy (Pct). In group I Yucatan miniature swine (n = 6), after induction of diabetes by Pct, repeated islet allo-Tx of ≥80% pure islets was performed. Islets obtained from two pigs of the Hanford breed were injected twice a week, half freshly isolated and half 48-h cultured, over a period of 11 days, for a total of 23,647 ± 1617 islet equivalents (IE)/kg recipient body weight (BW). In group II Yucatan miniature swine (n = 3), after Pct, a single allo-Tx of ≥80% pure islets, previously obtained from two donors of the Hanford breed, was performed, using a total of 22,416 ± 1124 IE/kg BW. In group III Yucatan miniature swine (n = 3), auto-Tx of 60–75% pure islets, averaging 2980 ± 424 IE/kg BW, was performed a few hours after Pct. Group IV Yucatan mini pigs (n = 3) underwent Pct and were used as diabetic controls. Group V animals (n = 3) were normal control Yucatan mini pigs. Porcine islets were isolated by a modification of the standard collagenase digestion and Ficoll gradient purification method. Donors and recipients were chosen on the basis of moderate to high mutual alloreactivity in mixed lymphocyte culture (MLC). In groups I and II, cyclosporine A (CsA) was started 4 days before allo-Tx, at the dose of 15 mg/kg IM, and then gradually reduced to 4 mg/kg IM. In all group I animals, normal fasting blood glucose (FBG) was restored within 2–3 weeks. Two normoglycemic pigs died of acute pneumonia at 33 and 112 days, respectively, and one animal became progressively hyperglycemic at 100 days. After 3 months, discontinuation of CsA treatment resulted in FBG increase in two group I animals. In one pig, CsA was stopped after 151 days, and normoglycemia persisted until euthanasia, after 8 months. In group II pigs, normoglycemia lasted 4–20 days, with a progressive increase of insulin requirement thereafter. In group III animals, after islet auto-Tx, normoglycemia lasted 7–10 days, while insulin daily requirement progressively increased thereafter, stabilizing at 0.4 IU/kg/day, corresponding to about one third of the amount required in diabetic controls. The single most important result in this series of experiments is that intraportal allo-Tx of a sufficient islet mass, divided in multiple subtherapeutic doses, produced a better metabolic long-term control in comparison to a single injection of the same amount of islets. The technique of multiple-donor repeated islet Tx may prove useful to overcome the problem of primary nonfunction or early graft failure, currently limiting the success of clinical islet Tx in most cases.

Laparoscopic cholecystectomy without intraoperative cholangiography: audit of long-term results

There is no uniform consensus on the utility of routine intraoperative cholangiography (IOC) during laparoscopic cholecystectomy (LC). In this paper, we present a 10-year retrospective audit of our cases of LC without IOC, performed by a search of readmission cases through our electronic database. Data regarding all patients subjected to LC at our unit in the period January 1996-December 2006 were obtained through our hospital database system. Subsequently, a query was made to ascertain if there were any readmissions to any of our city hospitals, up to December 2006. A total of 1321 patients underwent LC at our unit in the period January 1, 1996-December 31, 2006. The median operating time for LC without IOC was 58 minutes (range, 15-370). The median hospital stay was 2 days (range, 1-30). Postoperative outcome was uneventful in 1250 patients (94.7%). There was no mortality. Grade I and II complications occurred in the remaining 71 patients. Patients were stratified by risk of common bile duct stones (BDSs) according to clinical, ultrasonographic, and serum chemistry data. Patients with suspected BDS underwent preoperative endoscopic retrograde cholangiopancreatography (ERCP) and BDS clearance (142 patients). No patient in our series of LC was readmitted to any of the city hospitals for biliary desease up to 10 years after the operation. Our retrospective audit confirms the safety of LC without routine IOC and the rarity of readmissions for retained BDS and supports the policy of selective IOC.

Conversion rate in laparoscopic cholecystectomy: evolution from 1993 and current state

The definition of difficult laparoscopic cholecystectomy (LC) is inconsistent. The aim of this study was to analyze the factors that make LC difficult to perform and determine ways to avoid conversion, based on our series. All patients who underwent LC or open cholecystectomy (OC) between January 1993 and December 2001 in our division of general surgery were the subject matter of this study. Preliminary decisions regarding LC or OC were avoided. Our experience (1993-2001) was based on 1360 consecutive elective LC procedures in 381 male and 979 female patients. The mean age of the patients at operation was 53 years (range, 17-84). The median operating time was 55 minutes (range, 35-180). The overall conversion rate was 1.8%. Indications for conversion included surgical difficulty during the laparoscopic procedure and anesthesia issues. The conversion rate has decreased to less than 1% in recent years. There were no mortalities, and the postoperative complication rates were low. The mean hospital stay of the patients was 2.6 days. In conclusion, based on our experience, we suggest limiting OC to patients with proven contraindications to LC (i.e., Mirizzi syndrome or systemic illness incompatible with pneumoperitoneum), attempting LC in all other cases, and considering cholecystostomy and delayed LC as an alternative to conversion during difficult LC.

Conservative management of traumatic chylothorax: a case report

A case is presented of a right traumatic chylothorax, secondary to thoracic trauma with bilateral posterior eleventh rib fracture, treated by total parenteral nutrition and pleural drainage, with resolution within 2 weeks. On the basis of this clinical report and of a review of the literature, it is concluded that adequate conservative management should be initially the treatment of choice. Surgical treatment should be reserved to the cases in which clinical improvement does not occur within 2 weeks, and should consist of supradiaphragmatic thoracic duct ligation. Thoracoscopic fibrin glue injection has recently been described as a possible alternative treatment.

Laparoscopic appendectomy for acute and recurrent appendicitis: retrospective analysis of a single-group 5-year experience

BACKGROUND AND PURPOSE

Twenty years after the first report of laparoscopic appendectomy (LA), its role in the treatment of appendicitis is still under debate. We report herein a retrospective analysis of our cases of LA in the last 5 years, during which we adopted a policy of an almost uniform laparoscopic approach on a rather selected population composed mainly of women with acute or recurrent lower quadrant abdominal pain.

PATIENTS AND METHODS

Laparoscopic appendectomy was performed on 33 male and 98 female patients. The mean age at operation was 25.7+/-11.4 years (range 11-59 years). Acute appendicitis with localized or diffuse peritonitis was present in 34 cases. In the remaining 97 patients, the operation was performed for acute or recurring symptoms of lower quadrant abdominal pain.

RESULTS

There were no conversions to open surgery. The operating time was 45+/-17 minutes (range 30-110 minutes). The pathology examination of the removed appendices showed acute appendicitis in 34 cases and chronic inflammation in the remaining 97 patients. In one case, histology revealed a coexisting mucinous carcinoid that extended to the perivisceral fat, and a completion right hemicolectomy was performed. Complications were minor in most cases. Reoperation for deep abdominal abscess or hematoma was required in three cases. The mean hospital stay was 2.59+/-1.58 days (range 24 hours-11 days).

CONCLUSION

In our hands, LA has proven to be safe and effective. The laparoscopic operation has significant advantages in terms of lower invasiveness and better diagnostic capability. It is especially useful in women of child-bearing age, in whom it may be considered the procedure of choice.

Laparoscopic adjustable esophagogastric banding: preliminary results

BACKGROUND

Laparoscopic gastric banding is effective in surgical treatment of morbid obesity, but has had the drawback of specific complications, like slippage and gastric erosion. To prevent such complications, modifications have been used, including high retrogastric positioning above the bursa omentalis, complete anterior fixation by gastro-gastric stitches over the band, and reduction of the pouch volume to < or = 15 ml. These technical variants may induce dysphagia.

METHODS

We adopted a different technique, consisting of placement of the band (9.75 cm BioEnterics Lap-Band) around the esophagus just above the cardia, to induce an amplification of the dysphagic mechanism. No fixation stitches were used.

RESULTS

From January 1999 to March 2001, 80 consecutive patients (16 males, 64 females, mean age 41 years, average BMI 45) were operated this way. All operations were completed laparoscopically. However, in 1 patient the procedure had to be interrupted for bleeding from a large fatty liver injury by the retractor. Complications included 2 cases of slippage: an early one after 24 h, requiring surgical removal, and a late one after 9 months, treated by laparoscopic repositioning. The third complication, a reactive esophageal stenosis, occurred in a transsexual male on estrogen treatment, that needed replacement with a wider Swedish band. Band adjustment was required in 28 patients, one time in 22 cases and twice in the other 6. Mean BMI decreased from 45 to 38 after 6 months, remaining at 37 after 24 months, while excess weight was reduced by 50% at 24 months.

CONCLUSIONS

The technique has a re-educational function, in that patients are induced to chew thoroughly, to introduce small morsels of food and to prolong the mastication time, in order to avoid dysphagia. Laparoscopic adjustable esophagogastric banding gave no problem if well positioned, and promoted new alimentary habits through a dysphagic mechanisms, inducing significant excess weight loss.

Pancreatic beta-cell replication in streptozotocin-diabetic rats: the effect of liver compensatory growth on intraportally engrafted islets

Early studies showed that compensatory liver growth after anterior portal branch ligation (aPBL) may restore normoglycemia in streptozotocin (STZ)-diabetic rats, in which a subtherapeutic islet mass was previously transplanted into the liver. We hypothesized that this effect could be related to islet regeneration at the graft site. This study was designed to characterize the proliferative response of the intraportally transplanted islets, shortly after aPBL. Male Wistar-Furth rats were used as syngeneic islet donors and/or recipients. STZ-diabetic rats were divided in four groups: groups 1 and 2 underwent selective 250-islet transplantation (Tx) into the posterior liver lobes, followed by aPBL 10 days later; rats were killed 24 h (n = 9) and 48 h (n = 10) after aPBL, respectively; groups 3 and 4 underwent selective 250-islet Tx into the posterior liver lobes, followed by sham aPBL 10 days later; rats were killed 24 h (n = 3) and 48 h (n = 3) after aPBL, respectively. Two hours before killing, all animals were injected with 5'-bromo-2'-deoxyuridine (BrdU; 50 mg/kg, i.v.). Liver sections were immunostained for insulin and BrdU, and both hepatocyte and islet cell labeling index (LI) were calculated. Islet cell LI was 2.30+/-1.18% in group 1, 2.23+/-1.00% in group 2, 0.43+/-0.29% in group 3, and 0.39+/-0.21% in group 4 (group 1 vs. group 3: p<0.02; group 2 vs. group 4: p<0.01). Hepatocyte LI was 2.50+/-2.14% in group 1, 15.0+/-7.6% in group 2, 0.12 +/-0.04 in group 3, and 0.11+/-0.03% in group 4, respectively (group 1 vs. group 2: p<0.02; group 1 vs. group 3: p<0.001; group 2 vs. group 4: p<0.001). Our study showed that intraportally transplanted islets undergo a concurrent proliferative response after aPBL, although with a lower extent and a different timing when compared with the liver-cell response.

Effect of intravenous and intraperivenous injections of sclerosants (sodium tetradecyl sulfate and hydroxy polyethoxy dodecan) on the rat femoral vein

The sclerosant effect of injected tetradecyl sulfate of sodium (STS) and hydroxy polyethoxy dodecan (HPD) was studied in the rat femoral vein. Intravenous (i.v.) and intravenous plus perivenous (i.v. + p.v.) injections of both sclerosants and physiologic saline were compared as to vein lumen occlusion, fibrosis, phlogosis, and damage to the artery and surrounding nervous and muscular tissues. The study was carried out in 30 rats treated by STS, in 30 treated by HPD, and 15 animals were injected with saline. The neurovascular bundle and adjacent muscle were removed at 48 h, 7 and 30 days and examined histologically. I.v. injections of STS produced a solid occlusion of the vein in a significant number of cases, after 30 days (P less than 0.01). A statistically significant number of solid occlusions of the femoral vein resulted after i.v. + p.v. injection of STS and HPD, at 48 h, 7 and 30 days (P less than 0.05; P less than 0.01). There was no significant difference between STS and HPD after i.v. + p.v. injection. After i.v. + p.v. we recorded a marked inflammation of muscle with signs of focal necrosis, at 48 h and 7 days. Our study indicated that i.v. + p.v. injection of STS and HPD provided a high degree of efficacy as regards vein occlusion. On the other hand, i.v. + p.v. injection induced a severe inflammation and necrosis of the tissues surrounding the sclerosed vein. Extrapolating our results to the endoscopic sclerotherapy for esophageal variceal bleeding, we conclude that paravariceal injection of sclerosants is a dangerous procedure, even though efficacious to reduce variceal hemorrhage, owing to the high risk of iatrogenic ulcers and esophageal perforation caused by muscular and mucosal necrosis.

[In vitro experimentation of a new model of radial flow bioreactor containing isolated hepatocytes]

Hepatocyte based artificial liver support systems are under investigation to support acute liver failure patients. The main purpose of such systems is to serve as a bridge to liver transplantation, or to promote spontaneous liver recovery. Limitation in mass-transfer capacity makes hollow-fiber bioreactors unsuited for long-term functioning of hybrid devices. We developed a novel radial-flow bioreactor in which the fluid perfuses the module from the center to the periphery, after having diffused through a space occupied by a three-dimensional structure filled with the hepatocytes. Five grams of freshly isolated porcine hepatocytes were seeded into uncoated, woven-non woven, hydrophilic polyester fabric, overlaid by two polyethersulfone membranes. Liver cells were perfused with 37 degrees C-warm, oxygenated, serum-free tissue culture medium, in which NH4Cl and Lidocaine were added at the final concentration of 1 mM and 60 micrograms/ml, respectively. Ammonium chloride removal, urea synthesis, monoethylglycinexylide (MEGX), pO2, pCO2, and pH were measured throughout the 14 day duration of the study. In a separate set of experiments, a scaled-up version of the radial flow bioreactor containing 150 grams of cells was perfused for 7 h with recirculating human plasma and MEGX production was monitored. During the 2 weeks of the study, an increasing production of urea was paralleled by constant ammonium removal. MEGX concentration after Lidocaine addition increased throughout the 14 days of perfusion with tissue culture medium, as well as after 7 hour perfusion with human plasma. Under transmission and scanning electron microscopy cells appeared attached to the polyester and one to each other, displaying ultrastructural features typical of functioning hepatocytes. Our study showed that liver cells were metabolically active when perfused into the radial-flow bioreactor. This configuration allowed close contact between media, or plasma, and cells at a physiological flow rate, by equalizing the concentration of the perfusing components, including O2, throughout the module. Our results suggest a potential use of this system for temporary extracorporeal liver support in acute hepatic failure patients.

Abdominal aortic aneurysmectomy associated with a native iliac kidney. Case report

Abdominal aortic aneurysm (AAA) repair associated with a pelvic kidney is extremely rare. To date only 14 cases have been reported in the literature. The main problem during aortic cross clamping is kidney preservation. The purpose of this article is to record and additional case of AAA repair associated with a native pelvic kidney. The preservation has been successfully achieved by a distal aortic double clamping.

[Dysphagia after laparoscopic Nissen fundoplication]

The aim of the study was to consider all the factors associated with the development of postoperative dysphagia which, in its transitory form, can be present in as many as 40 to 70% of cases. From 1996 to 2007, 302 Nissen fundoplications were performed at our department of surgery. We divided this series into two groups, the first consisting of 149 cases (from March 1996 to March 2004) where short gastric vessels were not dissected (nl-VGB) and the second of 153 cases (from April 2004 to December 2007) where short gastric vessels were dissected (I-VGB).The incidence of postoperative dysphagia was distinctly lower in I-VGB than in nl-VGB (4.5% vs 19.5%). One month after operation, the incidence of postoperative dysphagia in I-VGB and nl-VGB was 12% and 1,5%, respectively, while 3 months after surgery the percentages were 2% and 0.5%. Exclusion of cases performed during the learning curve period yielded similar results. At postoperative examinations we noticed a substantial reduction in gastro-oesophageal reflux disease symptoms in both groups, with no significant difference between the two. L-VGB patients appeared clearly more satisfied after operation than nl-VGB patients (97% vs 88%), even if the results were similar after 3 months. Our experience confirms the good results obtained with Nissen fundoplication with a distinct, rapid reduction in postoperative dysphagia.

[Update on the subject of trophism and liver regeneration]

Present knowledge of hepatic trophism and regeneration after partial resection of the parenchyma is reviewed. The importance of the various factors influencing hepatic regeneration (so-called hepatotrophic factors) is stressed by examining the most interesting data reported in the literature. In particular, an attempt is made to classify such factors according to their origin (e.g. hepatic or extra-hepatic) and specificity of action. A brief discussion of the clinical implications of this research and current treatment for acute and chronic hepatic insufficiency, with particular reference to the latest surgical techniques, closes the paper.

[Radiofrequency Milligan-Morgan haemorrhoidectomy in the outpatient setting]

The demand for shorter admissions and quicker recoveries prompted us to adopt a new approach, favouring day surgery as the preferred organisational modality. Since 2004, 312 Milligan-Morgan haemorrhoidectomies have been performed at our department of surgery. The operations were performed at our proctological outpatient unit by means of LigasureTM with immediate discharge. In our study we observed postoperative bleeding in 3 cases (0.96%), while 4 patients (1.28%) required an ordinary admission. There were no cases of acute urinary retention in our experience. Operating time is about 12-16 minutes; and recovery time around 60-70 minutes. Over the period 1992-2003, 978 Milligan-Morgan haemorrhoidectomies were performed at our department of surgery using diathermy. Historical comparison of the results of the two groups shows a reduction in complications, operating times and recovery times. On the basis of our experience, radiofrequency ablation causes less postoperative pain and makes for shorter recovery times compared with diathermy, because of its lower tissue damage. The aim of the present study was to verify the safety and effectiveness of day surgery haemorroidectomy in selected cases.

[Laparoscopic surgical treatment of polycystic liver: a case report]

The preoperative diagnosis of polycystic liver is easily obtainable by ultrasound, while computed tomography is more sensitive for making the differential diagnosis versus other hepatic lesions. This report describes a case of polycystic liver with mass-related symptoms. A laparoscopic fenestration of the larger and superficial cysts was performed. At a three-years follow-up neither postoperative complications nor recurrent episodes were observed. A number of studies have shown that the rates of cyst and symptom recurrence are 9% and 4.5%, respectively, and that the reduction of liver volume is 12.5%. in our opinion the choice of adequate treatment must be based on an accurate evaluation of the patient's clinical aspects and on tthe characteristics of cystic lesions, such as number, size and location. In conclusion, laparoscopic fenestration of liver cysts is a safe, effective procedure for obtaining excellent outcomes in terms of absence of recurrence, as well as being a more sparing approach.

[Benign obstruction of the common bile duct: what is the current role of transduodenal sphincteroplasty?]

This paper is a critical review of the clinical records of 20 patients who underwent a Transduodenal Sphincteroplasty (PSP), from October 1990 to January 1992 at our Department (General Surgery). The age was 64.9 (14.2) years (mean and standard deviation), but 14 (70%) of those patients were older than 60 (range: 63 to 89) and 9 (45%) were in the 8th up to 9th decade of their lives. In 16 patients PSP was performed at the same time as cholecystectomy. Common bile duct (CBD) exploration was decided in 11 patients only on the basis of the intraoperative cholangiographic findings (evidence of CBD stones and/or benign stenosis of the Papilla of Vater) as demonstration of the permanent role of this examination in biliary surgery. Among the patients who underwent PSP some time after cholecystectomy, one had a lesion of the choledochus, sustained when he was cholecystectomized 15 days before. Because of the fact that recovery was prompt and definitely uneventful, PSP together with the infusion of somatostatin (SMTN) can be considered a useful approach to the treatment of the biliary fistula.

[Laparoscopic sleeve gastrectomy: technique and preliminary results]

According to the WHO about 300 million people in the world are affected by obesity with an increasing trend. The aim of the present study was to assess our preliminary results with sleeve gastrectomy. Over the period from June 2006 to March 2008, 25 laparoscopic sleeve gastrectomy were performed at our Department of Surgery for morbid obesity by the same surgeon. The operation consists in resection of approximately three quarters of the stomach with the creation of a long slender gastric tube, dividing the stomach vertically in two parts and removing all the left side with the greater curvature and gastric fundus. The mean age of the patients was 38 +/- 9 years, and the mean BMI 48 +/- 3. The mean operative time was 110 minutes, and the mean hospital stay 6 days. Mean intraoperative bleeding was negligible (20 cc). In our study we observed just one case of gastric leakage from the staple line, treated by surgical drainage and by placement of an endoscopic stent. There were no cases of bleeding of the resection margin and no long-term stenosis; there was no mortality. The mean follow-up was 18 months. BMI showed a mean reduction of about 17 points. During postoperative visits all the patients reported marked reduction of hunger sensation, together with a sense of early satiety. On the basis of these preliminary results we can consider laparoscopic sleeve gastrectomy as a safe, functional and definitive procedure that constitutes a valid alternative in bariatric surgery, though it is as yet not completely standardised and requires a longer follow-up.

[Acute and fulminant liver failure: experimental models]

Fulminant hepatic failure (FHF) is a complex clinical syndrome, with an invariably high mortality rate, that follows many possible and different infectious, pharmacologic and surgical liver injuries. The appearance of the syndrome is similar whatever the etiology, but the mechanisms which lead to the development of FHF are greatly varied. In order to understand the possible pathways which drive to FHF, experimental animal models have been used for a long time. Six requirements should be fulfilled by any FHF animal model: 1) reversibility; 2) reproducibility; 3) death from liver failure; 4) the presence of a therapeutic window; 5) the need of large laboratory animal; 6) minimal hazard to personnel involved in the study. In the present paper a number of models are reported and described, and advantages and disadvantages are discussed. It is concluded that with respect to the aforementioned criteria, no available experimental model is yet as satisfactory as expected.