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Biomedical subjects

J Honiger

Publications and source records attributed to J Honiger.

At least 37 records · Page 2Linked to original sources

[A good model of acute hepatic failure: 95% hepatectomy. Treatment by transplantation of hepatocytes].

The aim of this study was to develop in rats, a model of acute hepatic failure that mimics human fulminant hepatitis and to study the effect on survival of transplantation of isolated hepatocytes. This study showed that the mortality after 90% hepatectomy was reduced by the sole correction of hypoglycemia. On the other hand, 95% hepatectomy appeared as a reliable and reproductable model, associated with a period of hepatic coma, a deep disorder of coagulation, and a high mortality rate (> 80%) despite correction of hypoglycemia. In this model of acute hepatic failure, intraperitoneal transplantation of encapsulated isolated hepatocytes significantly reduced the mortality rate from 80% in the control groups to 31% in the transplanted group. A complete regeneration of the native liver was observed in all rats surviving. All animals survived after explantation of the hollow fibers. Well preserved hepatocytes were observed in hollow fibers two months after transplantation.

Animals↗

Permeability and biocompatibility of a new hydrogel used for encapsulation of hepatocytes.

A new high-water-content (83%) and highly permeable anionic polyelectrolyte hydrogel was obtained by phase inversion of a polymer solution containing 6% polyacrylonitrile-sodium methallylsulphonate, 91% dimethylsulphoxide and 3% physiological saline solution. Hydrogel-based hollow fibres (HFs) were fabricated with a co-extrusion apparatus in collaboration with Hospal (France). HFs have an internal diameter of 800 microns and a wall thickness of 100 microns. Experimental results demonstrated that hydrogel-based HFs were permeable to albumin (mol. wt 69,000) and human immunoglobulin G (150,000), but were impermeable to immunoglobulins A (170,000) and M (900,000) after 24 h of diffusion. In vitro, the viability of isolated rat hepatocytes injected into the HFs was 64 +/- 6% after 10 d versus 30 +/- 5% for hepatocytes cultured in Petri dishes (P = 0.0001). Under these conditions, the amount of albumin released by encapsulated hepatocytes was 12 +/- 3 micrograms/24 h/10(6) cells at day 10, whereas at that time no albumin was released by hepatocytes cultured in Petri dishes. In vivo, histological study of hydrogel HFs implanted up to 6 wk in the peritoneum of rats revealed a low inflammatory tissue reaction without giant multinucleate cells in the foreign tissue, which decreased after the third week. The survival rate of encapsulated hepatocytes was over 85% 45 d after transplantation in the peritoneum of syngeneic Lewis rats. Therefore, this hydrogel demonstrates highly favourable properties for encapsulation of hepatocytes with regard to its biocompatibility, permeability and ability to maintain hepatocytes in a functional state for prolonged periods.

Analysis of Variance↗

Transplantation of allogeneic hepatocytes without immunosuppression: long-term survival.

BACKGROUND: Hepatocyte transplantation could be an alternative to whole liver transplantation. Allogeneic hepatocytes are rejected if transplanted without immunosuppression. The aim of this study was to transplant allogeneic hepatocytes in the peritoneum and to protect them from rejection by encapsulation in a new semipermeable membrane. METHODS: Rat hepatocytes were encapsulated in hydrogel-based hollow fibers, obtained from AN69 copolymer, before being transplanted into the peritoneum of rats. Outcome of allogeneic hepatocytes encapsulated in hollow fibers was compared with that of syngeneic hepatocytes encapsulated in hollow fibers, with that of free allogeneic hepatocytes, and with allogeneic hepatocytes encapsulated in hollow fibers left open. Cell viability was assessed by erythrosin exclusion, structure by electron microscopy, and function by albumin release. RESULTS: Up to 90 days, viability of allogeneic hepatocytes in hollow fibers was greater than 80%. The structure remained normal at electron microscopy. Albumin release was 16.5 +/- 0.3 micrograms/24 hr/10(6) hepatocytes (day 15), 14.2 +/- 2.0 micrograms/24 hr/10(6) hepatocytes (day 30), 8.8 +/- 0.1 micrograms/24 hr/10(6) hepatocytes (day 60), and 11.4 +/- 0.3 micrograms/24 hr/10(6) hepatocytes (day 90). Free hepatocytes and hepatocytes in hollow fibers left open did not survive at day 15. CONCLUSIONS: Viability and function of encapsulated allogeneic hepatocytes were maintained up to 90 days after transplantation, without immunosuppression.

Acrylic Resins↗

Tubal sterilization by selective catheterization in an animal model.

RATIONAL AND OBJECTIVES: The feasibility of tubal occlusion by selective salpingography was tested in an animal model; three novel occluding materials also were tested for this application. METHODS: Unilateral selective salpingography was performed in three groups of six rabbits; fallopian tubes were embolized with ethanol (group 1), a hydrogel (group 2), or an occluding emulsion (Ethibloc, Laboratoire Princeps, Neuilly sur Seine, France) (group 3). Animals were killed 2 days or 30 days after the procedure, according to randomization; tubal patency and histologic modifications were evaluated. RESULTS: Selective tubal catheterization was obtained in 100% of the cases. In group 1, no satisfactory occlusion was obtained; in group 2, 65% of the tubes were occluded with little histologic damage; in group 3, 80% of the tubes were occluded, but significant inflammation and tissue necrosis were noted. CONCLUSION: Selective salpingography proved a suitable method for gaining access to the fallopian tube and allowed selective injection of occluding materials. More research is needed to determine a suitable occluding material, focusing on biocompatibility and on long-term efficacy.

Animals↗

[Transplantation of allogeneic hepatocytes without immunosuppression: long term survival].

UNLABELLED: Hepatocyte transplantation could be an alternative to whole liver transplantation. Allogeneic hepatocytes are rejected if transplanted without immunosuppression. The aim of this study was to transplant allogeneic hepatocytes in the peritoneum and to protect them from rejection by encapsulation in a new semi-permeable membrane. METHODS: Rats hepatocytes were encapsulated in hydrogel-based hollow fibers, obtained from AN69 polymer, before being transplanted into the peritoneum of rats. Outcome of allogeneic hepatocytes encapsulated in hollow fibers was compared to that of free allogeneic hepatocytes. Cell viability was assessed by erythrosine exclusion, morphology by electronic microscopy and function by albumin release. RESULTS: Up to 90 days, viability of allogenic hepatocytes in hollow fibers was above 80%. The morphology remained normal at electronic microscopy. Albumin release was 16.5 +/- 0.3 (day 15), 14.2 +/- 2.0 (day 30), 8.8 +/- 0.1 (day 60) and 11.4 +/- 0.3 micrograms/24 h/10(6) hepatocytes (day 90). Free hepatocytes did not survive at day 15. CONCLUSION: Viability and function of encapsulated allogeneic hepatocytes were maintained up to 90 days after transplantation, without immunosuppression.

Animals↗

Preliminary report on cell encapsulation in a hydrogel made of a biocompatible material, AN69, for the development of a bioartificial pancreas.

The occurrence of an inflammatory reaction represents the major obstacle to the development of any implantable system including micro and macroencapsulation. The purpose of this study was to describe an encapsulation method for cells using a membrane made of AN69, a copolymer of acrylonitrile which is considered as a reference in biocompatibility in the field of haemodialysis. The hydrogel of AN69 was obtained after a coagulation step at room temperature followed by a solvent/non-solvent (water) exchange phase. Microcapsules were obtained by co-extrusion of AN69 collodion and saline (with or without cells). The function of encapsulated cells was assessed in vitro, demonstrating cell survival after the microencapsulation procedure. These preliminary data are consistent with the potential interest for the development of the microencapsulation procedure aimed at realising a bioartificial pancreas.

Acrylic Resins↗

["Ex situ-in vivo" surgery of the liver: a new technique in liver surgery. Principles and preliminary results].

Major liver resections with complex vascular reconstruction require ischemia lasting from 2 h 30 to 5 h thus exceeding hepatic tolerance to warm ischemia. We describe a new technique of "ex situ-in vivo" liver surgery with prolonged ischemia with an intact hepatic pedicle. The surgical procedure encompasses complete mobilization of the liver and inferior vena cava, inferior mesenteric and femoral to axillary vein bypass, complete vascular exclusion of the liver, cold perfusion (U. W. solution), section of the hepatic veins allowing exteriorization of the liver ("ex situ") which remains connected by the hepatic pedicle ("in vivo"). The liver is placed on a heat exchanger at 4 degrees C. This procedure was performed in three patients: one each with hepatocellular carcinoma, huge metastasis of colorectal carcinoma and a "diffuse" hemangioma. Duration of ischemia was 225, 205, and 230 min respectively. The postoperative course was uneventful in all 3 cases and patients are alive at 15, 12, and 6 months. As it improves resecability rate of liver tumors and provides radical margins of resection, this procedure may be a beneficial alternative to liver transplantation for which poor results in cancer therapy with a high rate of recurrence are mainly due to immunosuppression.

Carcinoma, Hepatocellular↗

High-output external fistulae of the small bowel: management with continuous enteral nutrition.

Three hundred and thirty-five patients with high-output enterocutaneous fistulae arising from the small intestine are reported. Median fistula output was 1350 ml/24 h. Eighty-two per cent of patients were referred from other institutions. The fistula opening was associated with evisceration in 165 cases (49 per cent). One or more severity factors were present in 75.5 per cent of the patients. Patients were divided into three groups according to their initial therapy: 21 patients (6 per cent) referred in a moribund state were not operated on (non-intervention); 80 patients (24 per cent) were operated on as an emergency, and the fistula was either exteriorized or defunctioned; 234 patients (70 per cent) were initially managed conservatively. Appropriate local care and nutrition were provided in all cases. Enteral nutrition was the exclusive nutritional support in 285 patients (85 per cent). In 92 cases with proximal fistulae, methods limiting the fistula output or allowing reinfusion of chyme were required. The overall mortality rate was 34 per cent: 100 per cent in the non-intervention group, 55 per cent after emergency surgery, and 19 per cent after conservative treatment. In the latter group, spontaneous closure was obtained in 88 patients (38 per cent). Overall mortality rate was reduced to 19 per cent in patients treated since 1980. Enteral nutrition with appropriate local care may be used in the majority of high-output enterocutaneous fistulae, with an acceptable rate of spontaneous closure. Conservative management is the treatment of choice in the initial period. Emergency surgery should be restricted to the treatment of haemorrhage or intra-abdominal abscesses associated with uncontrolled systemic sepsis.

Adolescent↗

[Acute necroticohemorrhagic pancreatitis. Why, when and how to drain? Apropos of 106 cases].

The heavy toll of necrotizing acute pancreatitis led the authors to start developing a new method of treatment in experimental and clinical conditions in 1979. This was aimed on one hand at creating a large channel for the centrifugal drainage of pancreatic or peri-pancreatic foci, and on the other hand at maintaining this draining channel during the first 5 weeks of acute evolution of the acute necrotizing pancreatitis in order to allow the permanent evacuation of purulent or necrotic fragments. From 1979 to 1989, 106 patients were treated with this method, ie. 71 men and 35 women with an average age of 47.9 years. 73 (74%) of these patients had been referred by other hospitals, and 64 only had been initially operated at Saint-Antoine hospital. All patients presented with extensive peripancreatic necrosis. The average Ranson score was 4.8 (not taking the fluid sequestration during the first few hours into account). Visceral failure was observed in 76% of the patients before surgery. The necrosis of the pancreatic gland was focal in 6 cases, extensive in 47 cases and total or subtotal in 25 cases. Out of the 70 CT studies, 64 showed a Ranson grade of E. All patients received enteral feeding on a jejunal site postoperatively. The mortality rate was 16%. The stay of the surviving patients in the intensive care unit averaged 50 days. 29 patients (27%) were reoperated on for complications or insufficient drainage.

Adult↗

Septic necrosis of the midline wound in postoperative peritonitis. Successful management by debridement, myocutaneous advancement, and primary skin closure.

Wound management following laparotomy for postoperative peritonitis and varying degrees of parietal necrosis remains a challenging and controversial problem. Because maintained peritoneal integrity and primary wound closure offer the best opportunity for survival, an original technique involving bilateral incisions to relax skin and rectus fascia is proposed. This technique permits medial myocutaneous advancement and primary tension-free skin closure of midline laparotomy incisions. Sixty-nine patients with severe postoperative peritonitis were treated according from 1980 through 1985. Nine of these patients died of advanced multiple organ failure soon after referral, and eight more died after prolonged treatment. Fourteen patients had one or more reoperations for complications. Only nine wound failures resulted, including five eviscerations and four wound infections followed by progressive dehiscence. The bilateral relaxing incisions healed secondarily without complication. Survivors developed midline wound hernia; ten of the 52 surviving patients have had these repaired. This method of primary closure is safe when performed in conjunction with rigorous surgical care of intraperitoneal infection and may enhance survival. We recommend the technique to surgeons who treat severe postoperative peritonitis and septic necrosis of midline laparotomy wounds.

Debridement↗

Histological study of a polyamide arterial allograft (inside diameter: 1.5 mm) in rats.

The histological results of the implantation of twenty aortal prosthesis (6-6 polyamide, internal diameter 1.5 mm) in rats are presented. The success rate is 77%. Biological tolerance is remarkably good. After the first month, the formation of a continuous endothelial layer is noted. At three months, the structure of the neo-membrane resembles that of the aortal.

Animals↗

Surgical anatomy of liver segment IV.

Classical studies of the anatomy of the liver have led to the wide practice of hepatic resection. The difficulties encountered in the course of either right hepatectomy enlarged to include segment IV or left hepatectomy are mainly related to the vascular relations of this liver segment. This paper presents a summary of data from the literature concerning segment IV of the liver, as well as the results of experimental study via an original technique of resin injection of the portal vasculature and biliary drainage of this segment. The relations of the portal pedicles of segment IV with the bile duct originating from the confluence of the ducts draining segments II and III and with the left paramedian branch of the portal vein are described. Knowledge of these anatomical relations is essential to the proper execution of major hepatectomy.

Bile Ducts↗