Étude de la formation et de la stabilité des mousses chimiques de surface de la Vienne

Le recensement de la charge polluante rejetée dans la rivière Vienne (France) par les usines et les stations d'épuration de Limoges à Confolens a été effectué. Des campagnes de prélèvement et d'observations visuelles ont permis de localiser les lieux d'apparition de mousses en aval d'usines de fabrication de pâte à papier et de cartons. L'étude du pouvoir moussant des mélanges des deux principaux rejets polluants (papeterie et cartonnerie) a permis de mettre en évidence des phénomènes de synergie entre certains mélanges se traduisant à la fois par une augmentation du pouvoir moussant et de la stabilité de la mousse dans le temps. L'étude par « HPLC » montre l'apparition de pics supplémentaires confirmant l'interaction entre les constituants des rejets; le principal effluent a pu être suivi à l'aide de ses caractéristiques chimiques dans la rivière et dans les mousses jusqu'à Confolens.The study reported here considers of the formation and stability of foam on the Vienne river. Foaming is frequently encountered in relation to the discharge of industrial effluents, especially from the paper industry (CRAIG and al., 1990). Earlier papers have investigated the consequences of such discharges (NEILSON and al., 1990; KALLQVIST and al., 1989; SRIVASTAVA and al. 1988).The extent of foam formation is determined by a number of factors, including effluent composition, turbulence of the stream, etc. Foams stability requires the presence of long chain fatty acids, amine acids, tannins etc. Many industries discharge their effluents into the Vienne river (paper and cardboard industries, leather dressing plants and tanneries).An inventory of the main urban and industrial discharges has been established (Map 1). The effluents from the pulp, paper and cardboard industries provide the main pollution foad in terms of volume, COD, suspended solids (SS) and anionic surfactants.A visual survey allowed us to locus our investigations on the places where persistant foams appear, especially downstream of Saillat below the discharges from Aussedat Rey and SGPL (Picture 1), and below small waterfalls (Pont de Pilas, Chabanais, Ansac...). At Confolens, the foams are most stable and form stable drifting foam residues.Synergistic foaming effects have been reported due to the combination of polyamides and tannins (BIKERMAN, 1953). We have chosen to analyze the main effluents (Table 1) and their mixtures in relation to foaming (foaming capacity, foaming stability and surfactant analysis). The method used for foaming capacity determination was based on the hand shaking of 250 ml bottles. The stability of the foam was defined as the time for which the height of foam persists. Anionic surfactants were present at significant concentrations, varying from 1 mg/l (as sodium dodecyl sulphate) in the Aussedat Rey effluent to 4 mg/l in the SGPL effluent and 7 mg/l in the St Junien wastewater treatment plant effluent. The maximum foaming capacity was obtained for a 70/30 Aussedat Rey/SGPL effluent mixture (Fig. 1). The foaming capacity persists river time, remaining practically unchanged for three days. After 6 days, the maximum foaming capacity appears to be reduced. Foam stability is also maximum for the same 70/30 mixture (Fig. 2). After 6 days, the 50/50 and 70/30 mixtures can still produce 3 cm of foam that persist for 2 hours (Fig. 3).For HPLC analysis (20 µl samples), the effluents from AR and the effluents from SGPL (or the mixture of the two) were diluted in 10 times their volume of distilled water prior to analysis. Concerning the mixture 95 % AR - 5 % SGPL (95/5) the peak that characterizes the SGPL effluent starts appearing and growing at 6.76 min. With the proportions : 90/10 and 70/30, its retention time respectively diminishes from 6.34 min. to 5.58 min. Moreover an extra peak appears with the 70/30 mixture at 5.02 min. This extra peak is at its highest at 4.96 min. for a 50/50 mixture. At the same time the initial AR peak is decreasing. It is thus confirmed that one or more constituent: are formed on mixing the two effluents, as indicated by the synergistic effect described earlier for the foam capacity and stability analysis.Anionic surfactants were analyzed in the Vienne river (Fig. 5). Their concentration dramatically increase at point (4) (Pont de Pilas), just below the discharges from AR and SGPL. When the river flow increases, dilution masks the phenomenon. A drastic decrease in pollution appears in August when the industrial activity is reduced because of holidays (Fig. 7).The HPLC Vienne river analysis (Fig. 5) shows an important peak of pollution at point (4) (Pont de Pilas) characteristic of the AR effluent. At Chabanais point (5), the ARISGPL ratio is 95/5 and the peak of SGPL appears, perhaps, et 6.12 min (in the diluted effluents in the same ratio 95/5, it appears at 6.34 min). At Confolens (10), the intensity has diminished (after two days) and the Confolens foams are the same as those produced by a river sample without concentrated effect. No appreciable degradation has occurred, since the height of the peaks point 10 is similar as those of the chromatogram of point (5) in accord with the literature (LESZKIEWICZ and KINNER, 1988 ; COTE and OTIS, 1989)

Normal human adipose tissue functions and differentiation in patients with biallelic LPIN1 inactivating mutations

Lipin-1 is a Mg2+-dependent phosphatidic acid phosphatase (PAP) that in mice is necessary for normal glycerolipid biosynthesis, controlling adipocyte metabolism, and adipogenic differentiation. Mice carrying inactivating mutations in the Lpin1 gene display the characteristic features of human familial lipodystrophy. Very little is known about the roles of lipin-1 in human adipocyte physiology. Apparently, fat distribution and weight is normal in humans carrying LPIN1 inactivating mutations, but a detailed analysis of adipose tissue appearance and functions in these patients has not been available so far. In this study, we performed a systematic histopathological, biochemical, and gene expression analysis of adipose tissue biopsies from human patients harboring LPIN1 biallelic inactivating mutations and affected by recurrent episodes of severe rhabdomyolysis. We also explored the adipogenic differentiation potential of human mesenchymal cell populations derived from lipin-1 defective patients. White adipose tissue from human LPIN1 mutant patients displayed a dramatic decrease in lipin-1 protein levels and PAP activity, with a concomitant moderate reduction of adipocyte size. Nevertheless, the adipose tissue develops without obvious histological signs of lipodystrophy and with normal qualitative composition of storage lipids. The increased expression of key adipogenic determinants such as SREBP1, PPARG, and PGC1A shows that specific compensatory phenomena can be activated in vivo in human adipocytes with deficiency of functional lipin-1.—Pelosi, M., E. Testet, S. Le Lay, I. Dugail, X. Tang, G. Mabilleau, Y. Hamel, M. Madrange, T. Blanc, T. Odent, T. P. W. McMullen, M. Alfò, D. N. Brindley, and P. de Lonlay. Normal human adipose tissue functions and differentiation in patients with biallelic LPIN1 inactivating mutations

Bi-allelic loss-of-function OBSCN variants predispose individuals to severe recurrent rhabdomyolysis

Rhabdomyolysis is the acute breakdown of skeletal myofibres in response to an initiating factor, most commonly toxins and over exertion. A variety of genetic disorders predispose to rhabdomyolysis through different pathogenic mechanisms, particularly in patients with recurrent episodes. However, most cases remain without a genetic diagnosis. Here we present six patients who presented with severe and recurrent rhabdomyolysis, usually with onset in the teenage years; other features included a history of myalgia and muscle cramps. We identified 10 bi-allelic loss-of-function variants in the gene encoding obscurin (OBSCN) predisposing individuals to recurrent rhabdomyolysis. We show reduced expression of OBSCN and loss of obscurin protein in patient muscle. Obscurin is proposed to be involved in sarcoplasmic reticulum function and Ca²⁺ handling. Patient cultured myoblasts appear more susceptible to starvation as evidenced by a greater decreased in sarcoplasmic reticulum Ca²⁺ content compared to control myoblasts. This likely reflects a lower efficiency when pumping Ca²⁺ back into the sarcoplasmic reticulum and/or a decrease in Ca²⁺ sarcoplasmic reticulum storage ability when metabolism is diminished. OSBCN variants have previously been associated with cardiomyopathies. None of the patients presented with a cardiomyopathy and cardiac examinations were normal in all cases in which cardiac function was assessed. There was also no history of cardiomyopathy in first degree relatives, in particular in any of the carrier parents. This cohort is relatively young, thus follow-up studies and the identification of additional cases with bi-allelic null OBSCN variants will further delineate OBSCN-related disease and the clinical course of disease.Macarena Cabrera-Serrano, Laure Caccavelli, Marco Savarese, Anna Vihola, Manu Jokela, Mridul Johari, Thierry Capiod, Marine Madrange, Enrico Bugiardini, Stefen Brady, Rosaline Quinlivan, Ashirwad Merve, Renata Scalco, David Hilton-Jones, Henry Houlden, Halil Ibrahim Aydin, Serdar Ceylaner, Sarah Drewes, Jerry Vockley, Rhonda L. Taylor, Chiara Folland, Aasta Kelly, Hayley Goullee, Emil Ylikallio, Mari Auranen, Henna Tyynismaa, Bjarne Udd, Alistair R. R. Forrest, Mark R. Davis, Drago Bratkovic, Nicholas Manton, Thomas Robertson, Cullen O, Gorman, Pamela McCombe, Nigel G. Laing, Liza Phillips, Pascale de Lonlay, and Gianina Ravenscrof

Bi-allelic loss-of-function OBSCN variants predispose individuals to severe recurrent rhabdomyolysis

Rhabdomyolysis is the acute breakdown of skeletal myofibres in response to an initiating factor, most commonly toxins and over exertion. A variety of genetic disorders predispose to rhabdomyolysis through different pathogenic mechanisms, particularly in patients with recurrent episodes. However, most cases remain without a genetic diagnosis. Here we present six patients who presented with severe and recurrent rhabdomyolysis, usually with onset in the teenage years; other features included a history of myalgia and muscle cramps. We identified ten bi-allelic loss-of-function variants in the gene encoding obscurin (OBSCN) predisposing individuals to recurrent rhabdomyolysis. We show reduced expression of OBSCN and loss of obscurin protein in patient muscle. Obscurin is proposed to be involved in SR function and Ca2+ handling. Patient cultured myoblasts appear more susceptible to starvation as evidenced by a greater decreased in SR Ca2+ content compared to control myoblasts. This likely reflects a lower efficiency when pumping Ca2+ back into the SR and/or a decrease in Ca2+ SR storage ability when metabolism is diminished. OSBCN variants have previously been associated with cardiomyopathies. None of the patients presented with a cardiomyopathy and cardiac examinations were normal in all cases in which cardiac function was assessed. There was also no history of cardiomyopathy in first degree relatives, in particular in any of the carrier parents. This cohort is relatively young, thus follow-up studies and the identification of additional cases with bi-allelic null OBSCN variants will further delineate OBSCN-related disease and the clinical course of disease

Biallelic Mutations in LIPT2 Cause a Mitochondrial Lipoylation Defect Associated with Severe Neonatal Encephalopathy

Lipoate serves as a cofactor for the glycine cleavage system (GCS) and four 2-oxoacid dehydrogenases functioning in energy metabolism (α-oxoglutarate dehydrogenase [α-KGDHc] and pyruvate dehydrogenase [PDHc]), or amino acid metabolism (branched-chain oxoacid dehydrogenase, 2-oxoadipate dehydrogenase). Mitochondrial lipoate synthesis involves three enzymatic steps catalyzed sequentially by lipoyl(octanoyl) transferase 2 (LIPT2), lipoic acid synthetase (LIAS), and lipoyltransferase 1 (LIPT1). Mutations in LIAS have been associated with nonketotic hyperglycinemia-like early-onset convulsions and encephalopathy combined with a defect in mitochondrial energy metabolism. LIPT1 deficiency spares GCS deficiency and has been associated with a biochemical signature of combined 2-oxoacid dehydrogenase deficiency leading to early death or Leigh-like encephalopathy. We report on the identification of biallelic LIPT2 mutations in three affected individuals from two families with severe neonatal encephalopathy. Brain MRI showed major cortical atrophy with white matter abnormalities and cysts. Plasma glycine was mildly increased. Affected individuals' fibroblasts showed reduced oxygen consumption rates, PDHc, α-KGDHc activities, leucine catabolic flux, and decreased protein lipoylation. A normalization of lipoylation was observed after expression of wild-type LIPT2, arguing for LIPT2 requirement in intramitochondrial lipoate synthesis. Lipoic acid supplementation did not improve clinical condition nor activities of PDHc, α-KGDHc, or leucine metabolism in fibroblasts and was ineffective in yeast deleted for the orthologous LIP2