Modeling subsurface contaminant transport from a former open-pit uranium mine in fractured granites (La Ribière, France): Reducing uncertainties with geophysics.

The long-term management of tailings from former uranium (U) mines requires an in-depth understanding of the hydrogeological processes and water flow paths. In France, most of the legacy U mines are located in fractured crystalline (plutonic) rocks, where the intrinsic subsurface heterogeneity adds to the uncertainties about the former extraction and milling activities and the state of the mine when production was ceased. U ores were mainly processed by sulfuric acid leaching, leading to high-sulfate-content mill tailings now contained in several tailing storage facilities (TSFs). The La Ribière site, located in western central France, is a former open-pit and underground U mine, closed in 1992 and used to store mill tailings. This site is being used as a test case to establish a workflow in order to explain and predict water flow and subsurface contaminant transport. A conceptual model of water flow and sulfate transport, at the scale of the La Ribière watershed, is first developed based on available information and hydrogeochemical monitoring. Recent geophysical investigations allows refining this model. Electrical Resistivity Tomography (ERT) proves to be efficient at localizing the extent of the highly conductive sulfate plume inherited from the U-mill tailings, but also at imaging the weathering profile. Magnetic Resonance Sounding (MRS), despite the limited signal intensity due to the low porosity in crystalline rocks, gives some insight into the porosity values, the depth of the fractured layer and the location of the low-porosity ore-processing muds. Based on this conceptual model, a 3D flow and non-reactive transport model with the METIS code is developed and calibrated. This model allows predicting the evolution of the sulfate plume, but will also be used in future investigations, to build reactive transport models with simplified hydrogeology for U and other reactive contaminants.

Hepatodiaphragmatic interposition of the colon--an unusual case of combined anterior and posterior types treated with an original operative technique: report of a case.

Hepatodiaphragmatic interposition of the colon is rare. The posterior type is rarer than the anterior type. We observed a case of combined anterior and posterior types and used an original operative technique with a Prolene mesh to exclude the dead space and prevent recurrence.

Embryonic death of Mek1-deficient mice reveals a role for this kinase in angiogenesis in the labyrinthine region of the placenta.

Mek is a dual-specificity kinase that activates the extracellular-signal-regulated (Erk) mitogen-activated protein (MAP) kinases upon agonist binding to receptors. The Erk MAP kinase cascade is involved in cell-fate determination in many organisms. In mammals, this pathway is proposed to regulate cell growth and differentiation. Genetic studies have shown that although a single mek gene is present in Caenorhabditis elegans, Drosophila and Xenopus, two mek homologs, Mek1 and Mek2, are present in the mammalian cascade. In the present study, we describe a mutant mouse line in which the mek1 gene has been disrupted by insertional mutagenesis. The null mutation was recessive lethal, as the homozygous mutant embryos died at 10.5 days of gestation. Histopathological analyses revealed a reduction in vascularization of the placenta that was due to a marked decrease of vascular endothelial cells in the labyrinthine region. The failure to establish a functional placenta probably explains the death of the mek1-/- embryos. Cell-migration assays indicated that mek1-/- fibroblasts could not be induced to migrate by fibronectin, although the levels of Mek2 protein and Erk activation were normal. Re-expression of Mek1 in the mutant mouse embryonic fibroblasts (MEFs) restored their ability to migrate. Our findings provide genetic evidence that establishes the unique role played by Mek1 in signal transduction. They also suggest that mek1 function is required for normal response to angiogenic signals that might promote vascularization of the labyrinthine region of the placenta.

In vivo characterization of a fluoropassivated gelatin-impregnated polyester mesh for hernia repair.

The present study was undertaken to evaluate a new prototype mesh that consists of a knitted polyester structure treated with a fluoropolymer and impregnated with gelatin. The Fluoropassiv mesh, as well as two controls, the Surgipro polypropylene mesh and the Gore-Tex expanded polytetrafluoroethylene patch, were used for the repair of experimentally induced abdominal hernias in piglets and followed for scheduled implantation periods of 4, 15, and 60 days. At the sacrifice the mesh and surrounding tissue were excised for histological assessment of the healing sequence, for the identification of changes in hematologic and immunological characteristics, and for the measurement of the mechanical properties. After cleaning to remove the encroaching tissue, the explanted devices were monitored for biostability by infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The present study has demonstrated that the Fluoropassiv mesh provides adequate mechanical strength and compares favorably with the two controls. No exacerbated systemic or in situ hematologic or immunological reactions were observed with either the meshes of the patch material. Histological studies revealed that thick collagenous and vascularized tissue were well anchored to the three biomaterials as early as 15 days after implantation. The degree of tissue penetration differed depending on the device. Chemically, they proved stable over time.

In vitro characterization of a fluoropassivated gelatin-impregnated polyester mesh for hernia repair.

The surgical management of abdominal hernias requires prosthetic grafting in situations where the defect is too large or the surrounding tissue is not available for repair. Flat patches made of different biomaterials have been used in textile or microporous forms. The present work describes the results of an in vitro study comparing the morphological, mechanical, and chemical characteristics of a new textile prototype, Fluoropassiv, made of polyester fibers treated with a fluoropolymer and impregnated with gelatin to those of seven existing commercial meshes and patches made from polypropylene, polyester, polytetrafluoroethylene (PTFE) yarns, and expanded microporous PTFE graft. The morphological study revealed a diversity of structures having a minimal relative porosity of 70%, high bursting, and suture retention strengths in comparison with natural muscular tissue. Elasticmoduli proved to depend more on the direction of the textile the rigidity was higher for those materials having tight structure, like the Fluoropassiv and the Surgipro meshes (> 30 MPa), whereas those with more open structures, such as the Marlex, Trelex, Lars, Bard Teflon, and GoreTex structures, showed lower elastic modulus (10 mPa). In addition, chemical analyses confirmed no irregularities in the polymers used in all prostheses and demonstrated that the fluoropolymer coating of the Fluoropassiv was uniformly distributed. The innovative aspects in the construction of the knitted fabric Fluoropassiv appears to make it suitable for repairing hernias, and the inclusion of both continuous fluoropolymer surface treatment of polyester fibers and gelatin impregnation appears to improve the healing process.

[Sentinel networks. The national public health network. State information]. / Les réseaux sentinelles. Le réseau national de santé publique. L'information de l'Etat.

In the area of health, the information system used by the authorities is based on a series of networks that need to be coordinated. 1. State information: State information as regards health epidemiology was for a long time fragmented. The reasons for this relative ignorance are varied, and are based both on professional and technical factors (preference of physicians for personal exchange rather than for statistical analysis, difficulties in data collection and mathematical processing), and on socio-political factors (the euphoria of years of economic growth). For a long time only the causes of death were appropriately documented (cf. Mme Facy's report). In the last decade, a variety of initiatives has been directed towards all fields, and morbidity is becoming better defined thanks to the ORS (Regional Health Observatories) (cf. M. Garro's speech) and health registers (cf. M. Schaffer). Warning systems are becoming a principal preoccupation for most people in positions of authority, and explain the proliferation of surveillance networks. 2. Sentinel networks: A 'sentinel network' is an interactive surveillance system involving the collection of health data on a routine basis by a group of doctors (general physicians, biologists, etc.). Initially conceived for the surveillance of communicable diseases, they are also used for all diseases requiring early warning and rapid intervention (effects of sudden pollution, surveillance of drugs and poisons, etc.). These sentinel networks have expanded in our countries to complement the compulsory notification systems for infectious diseases, whose 'passive' nature often leads to under-notification (and therefore a non-representative selection) and delayed notification of cases, and whose range of influence does not cover all communicable diseases.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholecystectomy by minilaparotomy without muscle section: a short-stay procedure.

The aim of this prospective study was to assess the results of cholecystectomy performed by an incision characterized by its small size and absence of muscle section, to minimize postoperative discomfort, and shorten hospital stay. Surgical access was via a transverse division of the linea alba extending 1.5-2 cm on the rectus sheath, on both sides, without section of muscle. One hundred and ninety-one patients were operated on. Only 1 (0.5%) peroperative complication (injury of cystic artery) and 4 (2%) benign postoperative complications occurred. The mean postoperative hospital stay was 4.4 +/- 1.7 days (range 2 to 12); for the 90 patients operated on in 1989-1990 it was 3.3 +/- 1.7 days (range 2 to 12). Long-term results were assessed in 113 patients. Only 1 (0.6%) complication occurred, namely migration of a retained common duct stone. Neither incisional hernias nor a need for reoperation occurred. The cosmetic results were assessed by the patients themselves as very good in 95 (84.1%) cases and good in 16 (14.2%) cases.

[Inguinal herniorrhaphy under local anesthesia with short hospitalization]. / Herniorraphie inguinale sous anesthésie locale avec hospitalisation brève.

This prospective study gives short-term results of 208 inguinal herniorrhaphy performed under local anaesthesia. The median age of the 201 patients (186 M, 15 F) was 57 years (17-87). Local anaesthesia could not be achieved in 1 (0.5%) patient because he was panic-stricken. No serious complications occurred. Peroperative systemic hypotension with bradycardia occurred in 6 (3%) cases. Two (1%) benign postoperative sepsis and 9 (4%) hematoma occurred. The median postoperative hospital stay was 2.8 days (1-10). Twenty seven (13%) patients were discharged on the first postoperative day, 93 (46%) in a period of time less than or equal to 2 days, 147 (73%) in a period less than or equal to 3 days and 184 (91%) in a period less than or equal to 4 days.

[Medico-administrative aspects of medically assisted reproduction techniques]. / Aspects médico-administratifs des techniques de procréation médicalement assistée.

Artificial procreation techniques raise many ethical questions. The National Consultative Ethics Committee has pronounced on two occasions on this subject. Apart from ethical considerations, the rapid development of various techniques has required regulations aimed at ensuring the quality of the medical activities performed. The decree of April 8, 1988 concerning medically assisted procreation limits the practice of these activities to hospitals and medical biology laboratories. These regulations do not apply to fundamental questions which fall in the realm of legislation. A bill has already been drafted; if it passes it might provide a few guiding marks on this subject for practitioners and for society as a whole.

[Effect of proximal gastric vagotomy on the competence of the lower sphincter of the esophagus]. / Effet de la vagotomie fundique sur la compétence du sphincter inférieur de l'oesophage.

The aim of this prospective study was to assess the effects of highly selective vagotomy on lower esophageal sphincter pressure, and to determine whether or not it leads to increased gastroesophageal reflux. Fifteen patients (4 females, 11 males), mean age 43 years (22-63) suffering from duodenal ulcer without any clinical or pH evidence of gastroesophageal reflux were treated by highly selective vagotomy. All of them were studied before and 3-6 months after operation by history taking, pH reflux, manometric, and acid secretory pentagastrin tests. After operation none of the 15 patients had clinical evidence of duodenal ulcer or gastroesophageal reflux. The basal and stimulated acid outputs were decreased after vagotomy; pre and postoperative values were 6.8 +/- 8.9 mmol/h and 0.9 +/- 1.6 mmol/h; 42.2 +/- 10.3 mmol/h and 21.4 +/- 6.4 mmol/h, for BAO and PAO respectively (p less than 0.001). The lower esophageal sphincter pressure was 22.5 +/- 5.6 cm H20 before and 21.1 +/- 4.9 cm H20 after surgery (p less than 0.01). None of the values were lower than normal. There was no significant difference in pH reflux tests; the total duration of pH less than 5 reflux was 1.2 +/- 2.1 p. 100 before, and 1.9 +/- 2.8 p. 100 after vagotomy. These results suggest that an efficient highly selective vagotomy does not impair lower esophageal sphincter efficiency in patients-without gastroesophageal reflux, and that the routine addition of an antireflux procedure is not well advised.

[Results of the surgical treatment of common bile duct calculi in aged patients]. / Résultats du traitement chirurgical de la lithiase de la voie biliaire principale chez le sujet âgé.

One hundred and two patients (median age: 76 years old; range: 70-91) underwent choledocotomy for biliary lithiasis. Seventy patients had at least one risk factor, 31 had at least 2 factors and 12 had 3 or 4 factors. The indication for surgical treatment was based on evolutive complications in 64 cases; an elective operation was performed in 38 cases. Common bile duct lithiasis was present in only 87 cases but associated lesions made a choledocotomy necessary in every case. A choledocoduodenostomy was performed in 40 cases and a choledocojejunostomy in 3 cases. No postoperative complications occurred in 86 patients. Of 16 patients with complications, 2 were fatal being due to hemiplegia and respiratory failure respectively. Two patients had residual lithiasis. Ninety-four patients were followed on a long-term basis (median follow-up time: 6 years): 34 died from underlying diseases, while 60 are still alive. Treatment failures were, in one case, recurrent lithiasis treated by choledocoduodenostomy and, in the other case, biliary anastomosis stenosis. These results show that the surgical treatment of choledocolithiasis does not necessarily increase the mortality rate in the elderly.

Bartter's syndrome with normal chloride reabsorption during indomethacin treatment.

A 17-year-old male patient with Bartter's syndrome was admitted for renal function studies. This patient had persistent hypokalemia, first found at age 5; the diagnosis of Bartter's syndrome with renal hypersecretion of prostaglandins E2 and F2 alpha had been established at age 13. A congenital defect of chloride reabsorption was expected, but after 4 years of indomethacin treatment no such defect was found. Withdrawal of indomethacin for 1 week resulted in profound hypokalemia and the appearance of a chloride reabsorption defect, with an excessive urinary PGE2 and PGF2 alpha excretion, and a parallel decrease in plasma prostaglandin precursors. The cause of Bartter's syndrome in this patient seems to be renal hyperprostaglandinism.

[Recurrence of vascular prosthesis infection: treatment by bypass of the lower part of the thoracic aorta using abdominal approach]. / Récidive d'infection de prothèse vasculaire: traitement par pontage à partir de l'aorte thoracique basse abordée par voie abdominale.

Two years before admission a 72-year-old woman received an aortobifemoral bypass graft. When the graft became infected it was replaced by an axillofemoral bypass graft. This also became infected. In another attempt at revascularization, a bypass was installed between the lower part of the thoracic aorta and the two distal parts of the superficial femoral arteries, passing through the obturator foramen. Access to the lower part of the thoracic aorta was made through an abdominal incision, lowering the risk factors associated with such an intervention. At 18-month follow-up, the results were satisfactory; the graft was patent and not infected.

[Malaise and brief losses of consciousness after 65 years of age. Clinical diagnosis and value of complementary studies in 512 patients]. / Malaises et pertes de connaissance brèves après 65 ans. Diagnostic clinique et valeur des explorations complémentaires chez 512 malades.

A retrospective study of the diagnosis and causes of malaise and loss of consciousness has been conducted under the aegis of the French National Society of Internal Medicine. This multicentric and retrospective enquiry, which involved 512 patients, revealed that up to 44% of the malaise had no diagnostic label and that those of known aetiology were frequently due to cardiovascular disorders, such as postural hypotension (11.7%) or arrhythmia (9.5%). The study also demonstrated that the clinical enquiry was more important than complementary examinations which yielded few useful data.