A field-pilot for passive bioremediation of As-rich acid mine drainage.

A field-pilot bioreactor exploiting microbial iron (Fe) oxidation and subsequent arsenic (As) and Fe co-precipitation was monitored during 6 months for the passive treatment of As-rich acid mine drainage (AMD). It was implemented at the Carnoulès mining site (southern France) where AMD contained 790-1315 mg L-1 Fe(II) and 84-152 mg L-1 As, mainly as As(III) (78-83%). The bioreactor consisted in five shallow trays of 1.5 m2 in series, continuously fed with AMD by natural flow. We monitored the flow rate and the water physico-chemistry including redox Fe and As speciation. Hydraulic retention time (HRT) was calculated and the precipitates formed inside the bioreactor were characterized (mineralogy, Fe and As content, As redox state). Since As(III) oxidation improves As retention onto Fe minerals, bacteria with the capacity to oxidize As(III) were quantified through their marker gene aioA. Arsenic removal yields in the pilot ranged between 3% and 97% (average rate (1.8 ±â€¯0.8) ✕ 10-8 mol L-1 s-1), and were positively correlated to HRT and inlet water dissolved oxygen concentration. Fe removal yields did not exceed 11% (average rate (7 ±â€¯5) ✕ 10-8 mol L-1 s-1). In the first 32 days the precipitate contained tooeleite, a rare arsenite ferric sulfate mineral. Then, it evolved toward an amorphous ferric arsenate phase. The As/Fe molar ratio and As(V) to total As proportion increased from 0.29 to 0.86 and from ∼20% to 99%, respectively. The number of bacterial aioA gene copies increased ten-fold during the first 48 days and stabilized thereafter. These results and the monitoring of arsenic speciation in the inlet and the outlet water, provide evidences that As(III) oxidized in the pilot. The biotreatment system we designed proved to be suitable for high As DMA. The formation of sludge highly enriched into As(V) rather than As(III) is advantageous in the perspective of long term storage.

Biological attenuation of arsenic and iron in a continuous flow bioreactor treating acid mine drainage (AMD).

Passive water treatments based on biological attenuation can be effective for arsenic-rich acid mine drainage (AMD). However, the key factors driving the biological processes involved in this attenuation are not well-known. Here, the efficiency of arsenic (As) removal was investigated in a bench-scale continuous flow channel bioreactor treating As-rich AMD (∼30-40 mg L-1). In this bioreactor, As removal proceeds via the formation of biogenic precipitates consisting of iron- and arsenic-rich mineral phases encrusting a microbial biofilm. Ferrous iron (Fe(II)) oxidation and iron (Fe) and arsenic removal rates were monitored at two different water heights (4 and 25 mm) and with/without forced aeration. A maximum of 80% As removal was achieved within 500 min at the lowest water height. This operating condition promoted intense Fe(II) microbial oxidation and subsequent precipitation of As-bearing schwertmannite and amorphous ferric arsenate. Higher water height slowed down Fe(II) oxidation, Fe precipitation and As removal, in relation with limited oxygen transfer through the water column. The lower oxygen transfer at higher water height could be partly counteracted by aeration. The presence of an iridescent floating film that developed at the water surface was found to limit oxygen transfer to the water column and delayed Fe(II) oxidation, but did not affect As removal. The bacterial community structure in the biogenic precipitates in the bottom of the bioreactor differed from that of the inlet water and was influenced to some extent by water height and aeration. Although potential for microbial mediated As oxidation was revealed by the detection of aioA genes, removal of Fe and As was mainly attributable to microbial Fe oxidation activity. Increasing the proportion of dissolved As(V) in the inlet water improved As removal and favoured the formation of amorphous ferric arsenate over As-sorbed schwertmannite. This study proved the ability of this bioreactor-system to treat extreme As concentrations and may serve in the design of future in-situ bioremediation system able to treat As-rich AMD.

Disaccharide uptake by brush-border membrane vesicles lacking the corresponding hydrolases.

Intestinal disaccharide uptake was studied with isolated brush-border membrane vesicles lacking the corresponding hydrolase. Either 15-day-old chick intestine, lacking both trehalase and lactase, or newborn pig intestine, lacking sucrase, was used. Both animal species yielded osmotically active vesicles capable of D-glucose/Na+ cotransport with a positive overshoot test. Vesicles from either origin gave quantitatively similar results in regard to both initial uptake rates and relative vesicle volumes. The nontransported analogs D-mannitol and L-glucose were used as diffusion markers. When tested with the appropriate disaccharidase-lacking vesicles, lactose, trehalose and sucrose exhibited uptake rates indistinguishable from those of D-mannitol and L-glucose. These uptakes were unaffected by the presence or absence of Na+, phlorizin and Tris. Chromatographic analysis confirmed the lack of hydrolysis of each disaccharide after prolonged incubation. The inescapable conclusion seems to be that intact disaccharides are not transported through the brush-border membrane, their uptake occurring through simple diffusion.

Characterization of the D-glucose/Na+ cotransport system in the intestinal brush-border membrane by using the specific substrate, methyl alpha-D-glucopyranoside.

By using isolated membrane vesicles, we have investigated the tenet that D-glucose transport across the intestinal brush-border membrane involves at least two distinct, Na+-activated agencies (D-glucose transport systems S-1 and S-2), only one of which (S-1) can use methyl alpha-D-glucopyranoside (methyl alpha-glucoside) as a substrate. Our results with this glucose analogue show that: (a) As a function of time, methyl alpha-glucoside uptake exhibits a typical overshoot, similar to but smaller than that given by D-glucose with the same vesicle batch. (b) Nonlinear regression analysis of substrate-saturation curves reveals that, contrary to D-glucose, methyl alpha-glucoside transport involves a single transport system which we have identified as S-1. (c) Methyl alpha-glucoside exhibits an apparent affinity (defined as the reciprocal of Km) 4-times smaller than that of D-glucose for S-1 (Km(Dglucose) = 0.5 mM; Km(methyl alpha-glucoside) = 2 mM). However, methyl alpha-glucoside has a Vmax (230 pmol/mg protein per s) identical to that characterizing D-glucose transport by this system. (d) In the absence of Na+, methyl alpha-glucoside uptake is indistinguishable from simple diffusion, confirming that Na+ is an obligatory activator of S-1. (e) Phlorizin behaves as a fully competitive inhibitor of methyl alpha-glucoside transport (Ki = 18 microM), again indicating that S-1 is involved. (f) Neither phloretin nor cytochalasin B affects methyl alpha-glucoside uptake. We conclude that methyl alpha-glucoside is a substrate specific for S-1, which permits study of the properties of this system without interference by substrate fluxes taking place through any other channel.

Survival in a cohort of human immunodeficiency virus-infected tuberculosis patients in New York City. Implications for the expansion of the AIDS case definition.

BACKGROUND: The occurrence of pulmonary tuberculosis in human immunodeficiency virus (HIV)-infected persons is believed to represent a less severe stage of HIV-related disease with a more favorable prognosis than other acquired immunodeficiency syndrome (AIDS)-defining conditions; therefore, it has been excluded from the AIDS definition established by the Centers for Disease Control (Atlanta, Ga) criteria. METHODS: To determine the prognosis of patients with HIV-related tuberculosis, we assessed the clinical, immunologic, and HIV infection status of a cohort of male subjects aged 20 to 44 years who were hospitalized with tuberculosis but without AIDS in New York City hospitals from 1985 through 1986, and we determined their mortality through May 1991. RESULTS: The 58 patients who agreed to participate were largely (90%) nonwhite and had a high prevalence of pulmonary tuberculosis (90%) and HIV infection (53%). Patients who were HIV seropositive had significantly lower CD4 cell counts (median, 0.136 x 10(9)/L; range, 0.013 x 10(9) to 2.314 x 10(9)/L vs median, 0.765 x 10(9)/L; range, 0.284 x 10(9) to 2.333 x 10(9)/L), and, during the follow-up period, an 83% mortality rate that was 7.5 times higher than the 11% rate in seronegative subjects. Survival analyses revealed that for all HIV-seropositive subjects the probability of death at 30 months was 72% and the median survival was 21 months (95% confidence interval, 15.5 to 26.5 months), while for HIV-seropositive subjects with CD4 cell counts of 0.2 x 10(9)/L or less, the probability of death at 30 months was 92% and the median survival was 15.75 months (95% confidence interval, 14.0 to 17.6 months). CONCLUSION: The prognosis for patients with HIV-related pulmonary tuberculosis is poor, and those with CD4 cell counts of 0.2 x 10(9)/L or less have survival patterns similar to that of patients with AIDS. We believe that these data support the expansion of the AIDS case definition to include persons with both pulmonary tuberculosis and severe HIV-related immunosuppression.

The role of GLUT2 in dietary sugar handling.

GLUT2 is a facilitative glucose transporter located in the plasma membrane of the liver, pancreatic, intestinal, kidney cells as well as in the portal and the hypothalamus areas. Due to its low affinity and high capacity, GLUT2 transports dietary sugars, glucose, fructose and galactose in a large range of physiological concentrations, displaying large bidirectional fluxes in and out the cells. This review focuses on the roles of GLUT2. The first identified function of GLUT2 is its capacity to fuel metabolism and to provide metabolites stimulating the transcription of glucose sensitive genes. Recently, two other functions of GLUT2 are uncovered. First, the insertion of GLUT2 into the apical membrane of enterocytes induces the acute regulation of intestinal sugar absorption after a meal. Second, the GLUT2 protein itself initiates a protein signalling pathway triggering a glucose signal from the plasma membrane to the transcription machinery.

Biliary cholesterol absorption in normal and L-thyroxin-fed rats.

Infusion of bile containing labeled cholesterol into bile fistula rats has permitted an in vivo study of the movements and of the absorption of biliary cholesterol in the digestive tract. The specific activities of cholesterol were similar in the micelles and the sediment of the luminal content after a 6 hr infusion, indicating rapid exchange of cholesterol between these fractions. In animals fed a basal diet, the biliary cholesterol absorption was higher (83%) than that of dietary cholesterol (70%). Bile cholesterol is essentially absorbed in the jejunum while the absorption of cholesterol from the diet takes place all along the small intestine but preferentially in its second and third quarters. Both alimentary cholesterol and bile cholesterol enter the top cells of the villi in preference to those of the crypts. In L-thyroxin-fed rats, a parallel decrease in biliary and dietary cholesterol absorption was observed. The increase in the intestinal transit of cholesterol and epithelium cell renewal of the jejunum accounted for this observation.

Nursing education and clinical practice on child and adolescent psychiatric inpatient services: survey results.

OBJECTIVE: To evaluate the educational preparation of staff nurses working on child and adolescent psychiatric inpatient services. METHODS: A 40-item questionnaire was sent to 169 staff nurses in nine institutions. One hundred seventeen questionnaires (69.2%) were suitable for analyses. RESULTS: Respondents ranged in age from 22 to 52 years (mean = 34.7, +/- 7.43 years) and 87.2% (n = 102) were women. Seventy-one percent (n = 83) of the respondents agreed that basic nursing education inadequately prepared them for work on child and adolescent psychiatric inpatient services. Deficiencies were cited in psychopharmacology, child psychiatric diagnosis, child psychopathology, and milieu treatment. There were few differences across educational type. CONCLUSION: Recent advances in psychiatric epidemiology, psychopharmacology, and neuroscience merit greater attention in undergraduate nursing education. Child psychiatric institutions and professional nursing organizations have a role to play in continuing education.

Regressional analysis of attitudes toward male nurses.

This study examined the relationship between six demographic variables of 174 respondents and acceptance of males in the nursing profession. Multiple regression analysis indicated that only two variables, respondents' educational level and sex, significantly predicted attitudes toward male nurses. The implications inherent in these findings are discussed in light of the minority role status occupied by male nurses.

[Diagnosis and management of amenorrhea in adolescent girls]. / Diagnostic et prise en charge d'une aménorrhée chez l'adolescente.

Amenorrhea in adolescents can be primary, with or without breast development, or secondary. Whether amenorrhea is primary or secondary, height, body mass index, food intake, the level of physical activity per week, the presence of hirsutism or galactorrhea, pelvic pain and past history of intercourse need to be investigated. Initially, blood tests should include hCG, FSH, estradiol, testosterone and prolactin serum levels. This screening will discriminate between hypogonadotropic hypogonadism and amenorrhea from primary ovarian insufficiency (POI). In case of primary amenorrhea, hypogonadism may be due to congenital hypogonadotropic hypogonadism (HH) or more rarely acquired HH. If FSH is elevated, amenorrhea is due to primary ovarian failure, mainly related to Turner syndrome. If pubertal development is normal, a pelvic ultrasound should be performed. It may visualize a hindering of menses output or less frequently an absence of uterus, as in Rokitansky syndrome or androgen insentivity syndrome. The most frequent etiologies of secondary amenorrhea are polycystic ovarian syndrome (PCOS), functional hypothalamic amenorrhea and less frequently POI and hyperprolactinemia. The differential diagnoses of PCOS are late-onset 21-hydroxylase deficiency and very rare ovarian or adrenal tumors. When contraception is not necessary, hormonal replacement therapy, including estrogen and progestins should be administered in order to avoid hypoestrogenism. In case of PCOS, sequential progestins can be prescribed. A contraceptive pill can be considered when contraception is needed and/or when hyperandrogenism needs to be treated.

[Meno-metrorrhagia, dysmenorrhea in adolescents]. / Ménométrorragies, dysménorrhées de l'adolescente.

Menometrorrhagia is a common symptom in adolescents. It is idiopathic in most cases. In case of menometrorrhagia, it is necessary to exclude a pregnancy, a disorder of hemostasis, particularly the von Willebrand disease, as it represents the most common inherited disorder, and more rarely a chronic disease or an endocrinopathy. History of the bleedings, menstrual blood loss quantification by the Higham score and tolerance of the bleedings (blood pressure) should be evaluated. Laboratory testing includes hCG, ferritin level, a complete blood count, a prothrombin time, an activated partial thromboplastin. Management of menometrorrhagia is related to the severity of the blood loss. It associates antifibrinolytics or non-steroidal anti-inflammatory agents (NSAIDS) with hormonal treatments, such as estrogen-progestin oral contraceptive pill or cyclic oral progestins. Primary or functional dysmenorrhea concerns 40 to 90% of the teenagers and represents a frequent cause of school absenteeism. Management of primary dysmenorrhea is primarily based on a treatment by NSAIDS. In case of its inefficacy or if contraception is needed hormonal treatments, such as estrogen-progestin combined pill should be prescribed. It is very important when pelvic pain is chronic and not soothed by simple medications to look for a secondary dysmenorrhea, mainly endometriosis. In such cases, pelvic magnetic resonance imaging should be performed.

[Ovarian calcium and fertilization in female rats receiving a subchronic overdose of vitamin D3]. / Calcium ovarien et fécondation chez la ratte recevant une surcharge subchronique en vitamine D3.

Calcium is increasing in ovaries of adult female rats when D3 vitamin is given by stomach intubation for 7 and 15 days. Histochemical studies show the presence of spherular chalky deposits specially in granulosa of some follicles. In the same times atresia becomes evident and fecondation is reduced. Chemical determination of calcium content of ovary show calcium accumulation in this organ.

[Action of a dietary Mg2+ deficiency and overload in the male rat: measurement of certain parameters of testicular and spermatozoan activity]. / Action d'une carence et d'une surcharge alimentaire en Mg2+ chez le rat mâle: mesure de quelques paramètres de l'activité du testicule et du spermatozoïde.

The specific activities of several enzymes were investigated as possible markers of the Mg2+ impact on testicular and spermatozoa glucidic metabolism: no modification was noticed. However, as a reflection of hormonal metabolism, 17 beta-OH steroid-deshydrogenase activity, AMPc and testosterone levels were measured in the testes and showed significant variations.

In vivo plasma cholesterol exchanges in the digestive tract of the rat: effect of L-thyroxine.

Cholesterol exchanges between plasma and digestive organs (stomach, small intestine divided into jejunum and ileum, cecum plus colon) were studied in control and in L-thyroxine-fed rats receiving a constant venous infusion of (3H)-cholesterol for 3 or for 6 h and in unoperated rats by use of the isotopic equilibrium method. In control rats, total cholesterol radioactivity in the walls of stomach, intestine and cecumcolon averaged 0.50% of infused (3H)-cholesterol at the end of 6 h; between 70 and 75% of this radioactivity was located in the intestine. However, the relative transfer rates into these walls, expressed as tissue radioactivity for the same free cholesterol specific activity in the plasma at the moment of sacrifice, are nearly the same when expressed per gram of tissue (walls) or per milligram of DNA in the epithelial cells of the jejunum and the ileum. In thyroxine-fed rats, total cholesterol radioactivity in the walls reached 1.27% of infused (3H)-cholesterol after 6 h, the intestine still containing the major part of radioactivity (80%). The relative cholesterol transfer rates into the walls are unchanged in stomach, ileum and cecum-colon when compared to the controls. But in the jejunum, L-thyroxine causes a twofold increase in plasma cholesterol exchanges through the wall and through the epithelial cell membrane. Moreover, in the epithelial cell of the jejunum, this hormone increases the percentage of plasma cholesterol, as estimated by the isotopic equilibrium method. Plasma cholesterol radioactivity enters the lumen mainly through the jejunal mucosa L-Thyroxyine strongly enhances jejunal excretion of plasma cholesterol explaining the twofold increase of fecal cholesterol excretion.

Fructose transporter in human spermatozoa and small intestine is GLUT5.

We recently reported that the glucose transporter isoform, GLUT5, is expressed on the brush border membrane of human small intestinal enterocytes (Davidson, N. O., Hausman, A. M. L., Ifkovits, C. A., Buse, J. B., Gould, G. W., Burant, C. F., and Bell, G. I. (1992) Am. J. Physiol. 262, C795-C800). To define its role in sugar transport, human GLUT5 was expressed in Xenopus oocytes and its substrate specificity and kinetic properties determined. GLUT5 exhibits selectivity for fructose transport, as determined by inhibition studies, with a Km of 6 mM. In addition, fructose transport by GLUT5 is not inhibited by cytochalasin B, a competitive inhibitor of facilitative glucose transporters. RNA and protein blotting studies showed the presence of high levels of GLUT5 mRNA and protein in human testis and spermatozoa, and immunocytochemical studies localize GLUT5 to the plasma membrane of mature spermatids and spermatozoa. The biochemical properties and tissue distribution of GLUT5 are consistent with a physiological role for this protein as a fructose transporter.

Fixation of Clostridium difficile toxin A and cholera toxin to intestinal brush border membranes from axenic and conventional mice.

We have tested the in vitro binding of Clostridium difficile toxin A (enterotoxin) and cholera toxin to intestinal brush border membranes prepared from either conventional or axenic mice. Membranes from axenic mice were shown to be saturated at a lower toxin A concentration (at least 2.5 times lower). Because there were no significant differences between membranes from axenic and conventional mice in binding at low toxin A concentrations, the presence of the normal microflora seems to increase the number but not the affinity of brush border membrane receptors on the enterocyte surface. Corroborating the in vitro results, we observed that conventional mice were more sensitive to the pathological effects of toxin A given intragastrically than were axenic mice. In contrast, there was no difference in the binding characteristics of cholera toxin between membranes from conventional and axenic mice. We conclude that the presence of the mouse intestinal bacteria increases the number of C. difficile toxin A intestinal receptors but does not influence cholera toxin receptors.