Influence of homogenization treatment on physicochemical properties and enzymatic hydrolysis rate of pure cellulose fibers.

The aim of this study is to compare the effect of different homogenization treatments on the physicochemical properties and the hydrolysis rate of a pure bleached cellulose. Results obtained show that homogenization treatments improve the enzymatic hydrolysis rate of the cellulose fibers by 25 to 100 %, depending of the homogenization treatment applied. Characterization of the samples showed also that homogenization had an impact on some physicochemical properties of the cellulose. For moderate treatment intensities (pressure below 500 b and degree of homogenization below 25), an increase of water retention values (WRV) that correlated to the increase of the hydrolysis rate was highlighted. Result also showed that the overall crystallinity of the cellulose properties appeared not to be impacted by the homogenization treatment. For higher treatment intensities, homogenized cellulose samples developed a stable tridimentional network that contributes to decrease cellulase mobility and slowdown the hydrolysis process.

Influence of steam explosion on physicochemical properties and hydrolysis rate of pure cellulose fibers.

The aim of this study is to compare the effect of different steam explosion treatments on the physicochemical properties and the hydrolysis rate of a pure bleached cellulose. The results showed that moderate steam explosion treatments (severity factor below 5.2) did not appear to improve the enzymatic hydrolysis rate of the cellulose fibers. However, characterization of the samples showed a modification of the physicochemical properties of the cellulose, resulting in an increase of the water retention values (WRV) coupled to an increase of the overall crystallinity. For higher treatment intensities, an important thermal degradation of the cellulose was highlighted. This thermal degradation caused an important modification of the cellulose composition which leads to a decrease of the hydrolysis rate.

Carcinogenic potency of perfluorooctane sulfonate (PFOS) on Syrian hamster embryo (SHE) cells.

Perfluorooctane sulfonate (PFOS) is the degradation product of many fluoroderivatives and a widespread environmental contaminant. Its persistence, its long half-life in humans and its toxicity explain high concerns on human health side effects in future. PFOS is suspected to be a non-genotoxic carcinogen. In the present work, we assessed carcinogenic potential of PFOS by studying morphological transformation in Syrian hamster embryo (SHE) cells; cell transformation of SHE cells is an in vitro assay recommended by the Organization for Economic Cooperation and Development to detect carcinogens, genotoxic or not. Genotoxicity of PFOS and expression of PPARs genes in SHE cells were also measured. PFOS was shown to induce cell transformation (P < 0.05) at non-cytotoxic concentrations (0.2 and 2 µg/mL) (P ≤ 0.01). No genotoxic effect was recorded in the range of PFOS concentrations tested (2 × 10(-4) to 50 µg/mL) using the single-cell gel electrophoresis (comet) assay after 5 and 24 h of exposure. The expression of PPARs genes was measured by qPCR within the first 24 h and after 7 days of PFOS treatment. Results indicated an increased expression of ppar-ß/δ isoform as early as 24 h. After 7 days, the increase of ppar-ß/δ mRNA was significant at the concentrations inducing cell transformation (0.2 and 2 µg/mL), while overexpression of ppar-γ and ppar-α did not closely relate to effective concentrations. The results indicate that PFOS behave as a non-genotoxic carcinogen and impacted PPARs genes. Its cell transforming potential paralleled an increased expression of ppar-ß/δ.

Perfluorooctanoic acid (PFOA) acts as a tumor promoter on Syrian hamster embryo (SHE) cells.

Perfluorooctane sulfonate (PFOS) (C(8)F(17)SO(3)) and perfluorooctanoic acid (PFOA) (C(8)HF(15)O(2)) are synthetic chemicals widely used in industrial applications for their hydrophobic and oleophobic properties. They are persistent, bioaccumulative, and toxic to mammalian species. Their widespread distribution on earth and contamination of human serum raised concerns about long-term side effects. They are suspected to be carcinogenic through a nongenotoxic mode of action, a mechanism supported by recent findings that PFOS induced cell transformation but no genotoxicity in Syrian hamster embryo (SHE) cells. In the present study, we evaluated carcinogenic potential of PFOA using the cell transformation assay on SHE cells. The chemical was applied alone or in combination with a nontransformant concentration of benzo[a]pyrene (BaP, 0.4 µM) in order to detect PFOA ability to act as tumor initiator or tumor promoter. The results showed that PFOA tested alone in the range 3.7 × 10(-5) to 300 µM did not induce SHE cell transformation frequency in a 7-day treatment. On the other side, the combination BaP/PFOA induced cell transformation at all PFOA concentrations tested, which revealed synergistic effects. No genotoxicity of PFOA on SHE cells was detected using the comet assay after 5 and 24 h of exposure. No significant increase in DNA breakage was found in BaP-initiated cells exposed to PFOA in a 7-day treatment. The whole results showed that PFOA acts as a tumor promoter and a nongenotoxic carcinogen. Cell transformation in initiated cells was observed at concentrations equivalent to the ones found in human serum of nonoccupationally and occupationally exposed populations. An involvement of PFOA in increased incidence of cancer recorded in occupationally exposed population cannot be ruled out.

Follow-up of stable chromosomal aberrations in gamma-ray irradiated non-human primates.

PURPOSE: The purpose of this study was to examine a new approach to retrospective biological dosimetry, by using a long-term animal model to determine the stability of translocation frequency after in vivo irradiation. While the frequency of dicentrics is known to decrease over time, the persistence of more stable chromosomal aberrations such as translocations could be useful if their stability were definitively proved. MATERIALS AND METHODS: Four monkeys (Macaca fascicularis) were exposed to two different doses of ionizing radiation: 2 Gy whole body irradiation for two and 4 Gy for two others. Blood samples were obtained at various times after irradiation. Both total and two-way translocations were detected by fluorescence in situ hybridization. Translocations were scored in stable cells, that is, those without dicentrics, rings or fragments. The course of translocation frequency was analysed at four time-points: one hour (H1), 2 months (M2), 10 months (M10) and 31 months (M31) after irradiation. RESULTS: We observed two separate trends in translocation frequency: Total translocation frequency decreased slightly in animals irradiated with a dose of 2 Gy, while two-way translocation frequency was relatively stable in all irradiated animals. CONCLUSIONS: We confirmed the long-term stability of translocations and found that it seems to depend on the type of the translocation recorded. Overall translocations were stable for up to 31 months regardless of dose, but two-way translocations were more stable than those that were non-reciprocal, especially in stable cells.

Strictureplasty in Crohn's disease: short- and long-term follow-up.

Strictureplasty for obstructive Crohn's disease is still controversial because lesions are left in place and the suture is performed on a diseased bowel. Many surgeons prefer to perform bowel resection, hoping for fewer complications and a lower recurrence rate. In this paper, the authors reports their strictureplasty experience. They performed a systematic retrospective review of the patients suffering from Crohn's disease who underwent strictureplasties during a 10-year period in the abdominal surgery department of the University Hospital of Liège Sart Tilman, and studied the short- and long-term clinical results of 68 strictureplasties performed in 18 patients. Median follow-up was 63 months (range 12 to 144). Mortality was 0% and septic morbidity was 11% (one wound abscess and one leakage). Among the 16 patients available for the latest follow-up, symptomatic stenotic recurrence had to be medically treated in hospital for 4 patients (25%) with a recurrence delay range of 19 to 49 months. Stenosis recurrence needed re-intervention in one patient 48 months after surgery: stenosis occurred at a distance from the corrected site. These results confirmed that strictureplasty is a safe and efficient procedure in selected patients undergoing surgery for obstructive Crohn's disease.

A case of hepatic alveolar echinococcosis contracted in Belgium.

We report herein the case of a Belgian 76-year-old woman who developed a hepatic tumour suspected to be a breast cancer metastasis. Radiological imaging and guided biopsies were not contributive. The patient underwent an explorative laparoscopy with frozen sections that did not provide further diagnosis, and an open left bisegmentectomy was performed during the same anaesthesia. Histopathological examination of the hepatic mass showed Echinococcus multilocularis metacestodes, demonstrating alveolar echinococcosis. As our patient denied any travel in foreign countries and has undergone regular abdominal ultrasonographies since her mastectomy, it is highly likely that this alveolar echinococcosis had been contracted in Belgium. If some imported cases may be seldom managed in Belgium, to our knowledge, this case is the first occurrence of alveolar echinococcosis contracted in Belgium. This report, added to the demonstration of E. multilocaris infection of 50% of red foxes in Southern Belgium, and the potential infection of domestic cats and dogs, should attract attention of the medical community on the possible outbreak of endemic alveolar echinococcosis in Belgium, and on the related public health concerns.

[Update on pancreatic transplantation]. / Le point sur la transplantation pancréatique.

Pancreas transplantation significantly improves the quality of life as well as the survival of the diabetic patient. It is also associated with stabilization and reversal of secondary diabetic complications. Improvements in organ preservation, surgical techniques and immunosuppression have achieved one-year graft survival of more than 90% for combined kidney-pancreas transplant and 80% for isolated pancreas transplantation. Recipient evaluation must weigh the benefits of the procedure with the risk associated with surgery and chronic immunosuppression. Combined kidney-pancreas transplantation appears today as the best treatment for the diabetic patient with end stage renal disease. Isolated pancreas transplantation is reserved to non-uremic patients with severe diabetic complications or with brittle glycaemic control and severe impairment of quality of life.

In vitro irradiation of blood with 99mTc: evaluation of dose and chromosome aberrations in irradiated lymphocytes.

The use of ionizing radiation for diagnostic or therapeutic purposes in medicine represents the principal source of artificial radiation to humans. Calculation of radiation dose is essential to the analysis of risks (biological effects) and benefits in any application, including nuclear medicine. The dose assessment in many cases is not necessarily straightforward. Many radiopharmaceuticals are labelled with radionuclides that undergo not only gamma-emission but also emission of Auger and internal conversion electrons. A typical example is technetium-99m (99mTc), which is used in more than 80% of nuclear medicine applications. In this work, in vitro studies have been carried out to evaluate the dose delivered to lymphocytes by human serum albumin microspheres (HSAM) labelled with 99mTc. Experiments were performed in order to score unstable chromosomal aberrations induced by 99mTc-HSAM, using conventional cytogenetic techniques. Henceforth, the relationship between activities introduced into blood samples and induced chromosomal aberrations were evaluated. To assess the dose absorbed in lymphocytes, electron and photon transport was performed in a simple model representing the system used for irradiating the cells using the MCNP Monte Carlo code. In this report, analysis of dose-effect curve demonstrates a linear quadratic response for unstable chromosome aberrations.

Autoimmune pancreatitis mimicking cancer of the head of pancreas: report of two cases.

Autoimmune pancreatitis has been characterised in 1995, but only a few cases have been published since then, most of them from Japan. This report describes the cases of two Belgian male patients who presented with isolated obstructive jaundice. Radiological imaging studies were highly suggestive of carcinoma of the head of pancreas and both patients underwent uneventful cephalic pancreaticoduodenectomy with portal vein resection. Pathological analysis of the removed tissues suggested an autoimmune process in both cases. Both patients had hyper-gammaglobulinemia and antinuclear antibodies, but failed to show evidence of any other autoimmune disease or cause of chronic pancreatitis. In both cases final diagnosis was autoimmune pancreatitis. Preoperative clinical suspicion of this diagnosis is mandatory and may avoid unnecessary surgery in future cases.

Level of Flt3-ligand in plasma: a possible new bio-indicator for radiation-induced aplasia.

PURPOSE: To follow plasma Flt3-ligand (FL) concentrations in irradiated animals in order to evaluate it as an indicator of bone marrow damage for the management of accidental radiation-induced aplasia. MATERIALS AND METHODS: Non-human primates were irradiated at doses ranging from 2 to 8 Gy, using whole- or partial-body irradiation. Plasma FL concentrations and blood cell counts were determined daily. RESULTS: FL concentrations increased as early as day 2 after irradiation, whatever the irradiation dose. Increase in plasma FL concentration on day 5 post-irradiation was correlated with radiation dose and with the severity of radiation-induced aplasia. During the course of aplasia, FL concentrations in plasma were inversely correlated with neutrophil counts. A peak in FL concentration appeared before the neutrophil nadir, and the subsequent decrease in FL concentration was correlated with the recovery of blood-cell populations. CONCLUSIONS: Monitoring plasma FL concentration can be used as an indicator of radiation-induced marrow aplasia, and this may be of use in accidental irradiation situations.

Seventy-two hours hypothermic intestinal preservation study using a new perfluorocarbon emulsion.

We investigated the effect of a perfluorocarbon emulsion (FC) added to the University of Wisconsin (UW) solution on hypothermic (4 degrees C, 12-72h) preservation of rat small bowel grafts. The FC was 90%w/v perfluorooctylbromide, 2%w/v egg yolk phospholipids and 1.4%w/v mixed fluorocarbon-hydrocarbon molecular dowels. Four groups were defined: [1] UW flush and UW storage; [2] UW flush and FC storage; [3] flush with FC diluted 2 times with UW (FU) and FU storage; [4] FU flush and storage in oxygenated FU. Preservation was estimated with a histological score based on villus epithelium adhesion, on villus sloughing and on crypt cell adhesion to the basal membrane. Antioxidant potential was estimated by measurement of total thiol functions (SH) and activities of glutathione-peroxidase (GSH-P), superoxide dismutase (SOD) and catalase. FC in flush improved preservation during the first 24h (p<0.01). Storage in FC appeared superior to UW for the first 24h (p<0.01). Oxygenation (100% O2) of the storage medium yielded superior results at 12h and 24h (p<0.01 and p<0.001 versus group [1] respectively). After 72h, SOD and catalase activities increased in groups [3] and [4], and SOD decreased in group [1] (p<0.05). SH progressively decreased in group [1] (p<0.05) and GSH-P increased at 24 and 48h in groups [3] and [4] (p<0.01). The increase of O2 in the perfusion flush or storage medium ameliorated the preservation status and protected the antioxidant potential of the small bowel.

Right hepatic lobectomy as a liver graft-saving procedure.

Retransplantation is common after liver transplantation (LT). However, in the present era of organ shortages, every attempt to save the liver graft should be performed before considering retransplantation. We report our experience with right hepatic lobectomy (RHL) for liver graft salvage. In a retrospective series of 180 adult LTs, 4 patients underwent RHL (Couinaud's segments V, VI, VII, VIII) in the post-LT period. In all cases, the procedure was performed without Pringle's maneuver or mobilization of the left liver lobe to preserve its vascularization. Three liver graft recipients developed intrahepatic biliary strictures, mainly localized to the right lobe of the graft, and RHL was performed 14, 75, and 78 months after LT. These patients were alive at last follow-up without further episodes of cholangitis or retransplantation (mean follow-up, 38 months). The fourth patient developed early post-LT right liver necrosis with a functioning hepatic artery and underwent right lobectomy 48 hours after LT. He later developed cholangitis secondary to late hepatic artery thrombosis, requiring retransplantation after 18 months. We conclude that RHL can be considered a graft-saving option in selected liver transplant recipients with localized biliary strictures, with excellent patient and graft survival.

Ileo-caecal actinomycosis: report of a case simulating complicated inflammatory bowel disease.

Abdominal actinomycosis is a rare infectious disease caused by Actinomyces israelii, a gram-positive anaerobic saprophyte germ that is a normal inhabitant of the upper intestinal tract in humans. Actinomyces israelii rarely cause abdominal infections or actinomycosis. Abdominal actinomysosis is characterised by fistulae and abscesses and may mimic cancer or inflammatory bowel disease. Abdominal actinomycosis is difficult to diagnose preoperatively, and often require surgical removal of the diseased tissue, allowing pathologists for giving the definitive diagnosis, revealed by characteristic "sulfur granules". The authors report herein the case of a 47-year-old man who presented with diarrhoea and abdominal pain. Abdominal computed tomography evoked complicated inflammatory bowel disease and surgical procedure was decided. Laparoscopic exploration did not provide further significant information, and laparotomy with diseased bowel resection was performed. Pathology demonstrated "sulfur granules" and allowed the diagnosis of abdominal actinomycosis. This case demonstrated that abdominal actinomycosis should be included in the differential diagnosis when computed tomography shows an infiltrative and inflammatory mass.

[Alpha-1-antitrypsin deficiency. An indication for pediatric liver transplantation]. / Le déficit en alpha-1 antitrypsine. Une indication de transplantation hépatique pédiatrique.

Alpha-1-antitrypsin deficiency is the most common inborn error of metabolism leading to liver transplantation, and the second cause of liver transplantation in children after biliary atresia. The authors report the case of a 6-year-old girl, who was suffering from end-stage liver disease secondary to alpha-1-antitrypsin deficiency. She was successfully treated by whole liver transplantation, the hepatic graft coming from a 3-year-old donor. Three months later she went back to school. The authors discuss the pathogenesis and the natural history of this frequent cause of liver transplantation in children.

Early stage results after oesophageal resection for malignancy - colon interposition vs. gastric pull-up.

OBJECTIVE: The aims of our study were to determine if using the colon as a digestive transplant after oesophagectomy for cancer was associated with increased postoperative complications, and to assess the impact of preoperative radiochemotherapy on postoperative hospital outcome. METHODS: From January 1990 to December 1998, 130 patients underwent oesophageal resection for malignancy. There were 103 males and 27 females (age: 61.3+/-11.5 years). Indications were squamous cell carcinoma in 69 patients and adenocarcinoma in 61. Preoperatively 30 patients (eight in stage IIB, 18 in stage III, and four in stage IV) received radiochemotherapy. There were 84 subtotal oesophagectomies, with anastomosis in the neck in 44 patients and at the thoracic inlet in 40, and 46 distal oesophageal resections. Digestive continuity was restored with the stomach in 92 patients (age: 63.4+/-10.2 years) and the colon in 38 (age: 52.3+/-12.8 years). With the exception of age (P<0.0001), there was no significant preoperative difference between gastric and colonic groups. RESULTS: Hospital mortality was 8.5% (11 patients), decreasing from 18.5% (before 1993) to 3.8% (since 1993). One patient (2.5%) died in the colonic graft group and ten (11%) in the gastric pull-up group (P=0.17). Postoperative complications occurred in 40 patients (31%), respectively, in ten (26%) and 30 (33%) patients after colonic and gastric transplants (P=0.48), and were pulmonary insufficiency or infection in 29 patients, anastomotic fistula in six, myocardial infarction in five, recurrent nerve palsy in four, renal insufficiency in three, and cerebrovascular accident in one. All fistulas occurred in the gastric pull-up group. The incidence of postoperative pulmonary complications was 70% (21/30 patients) in the subgroup who received preoperative radiochemotherapy, as compared to 11% (5/44 patients) in the subgroup of comparable staging, but without preoperative treatment (P<0.001). CONCLUSIONS: Colonic grafts are not associated with increased postoperative mortality or complications. Our results suggest that preoperative neoadjuvant treatment significantly increases postoperative pulmonary complications.

Organ donors with primary central nervous system tumor.

Patients with primary central nervous system (CNS) tumor have been accepted for organ donation because these tumors very rarely spread outside the CNS. However several case reports of CNS tumor transferral with organ transplantation recently challenged this attitude. Some risk factors for extraneural spread of CNS tumors have been determined, but the absence of risk factors does not exclude the possibility of metastases. To our knowledge, 13 cases of CNS tumor transferral with organ transplantation (one heart, three livers, eight kidneys, one kidney/pancreas) have been reported in the literature. Even if no prospective evaluation of the CNS tumor transmission risk with transplantation has been undergone, this risk may be estimated between a little more than 0% and 3% from retrospective series. The authors consider that patients with CNS tumor should be accepted as donors as long as the risk of dying on the waiting lists is significantly higher than the tumor transferral risk. Therefore the authors would have no restriction for transplanting organs from donors with benign or low-grade CNS tumor. For high-grade tumors, the authors would consider these donors as "marginal donors," and balance the risk of tumor transmission with the medical condition of the recipient.