Neurodevelopment at 2 years and umbilical artery Doppler in cases of very preterm birth after prenatal hypertensive disorder or suspected fetal growth restriction: EPIPAGE-2 prospective population-based cohort study.

OBJECTIVE: To investigate the association between absent or reversed end-diastolic flow (ARED) on umbilical artery Doppler ultrasound and poor neurological outcome at 2 years of age after very preterm birth associated with suspected fetal growth restriction (FGR) or maternal hypertensive disorders. METHODS: The study population comprised all very preterm (22-31 completed weeks) singleton pregnancies delivered because of suspected FGR and/or maternal hypertensive disorders that had umbilical artery Doppler and 2-year follow-up available included in EPIPAGE-2, a prospective, nationwide, population-based cohort of preterm births in France in 2011. Univariate and two-level multivariable logistic regression analyses were used to assess the association of ARED in the umbilical artery, as compared with normal or reduced end-diastolic flow, with severe or moderate neuromotor and/or sensory disability and with an Ages and Stages Questionnaire (ASQ) score below a threshold. This was defined as a score more than 2 SD below the mean in any of the five domains, at age 2, adjusting for gestational age at delivery. ASQ is used to identify children at risk of developmental delay requiring reinforced follow-up and further evaluation. Descriptive statistics and bivariate tests were weighted according to the duration of the inclusion periods. RESULTS: The analysis included 484 children followed up at 2 years of age, for whom prenatal umbilical artery Doppler ultrasound was available. Among them, 8/484 (1.6%) had severe or moderate neuromotor and/or sensory disability, and 156/342 (45.4%) had an ASQ score below the threshold. Compared with normal or reduced end-diastolic flow in the umbilical artery (n = 305), ARED (n = 179) was associated with severe or moderate neuromotor and/or sensory disability (adjusted odds ratio (OR), 11.3; 95% CI, 1.4-93.2) but not with an ASQ score below the threshold (adjusted OR, 1.2; 95% CI, 0.8-1.9). CONCLUSION: Among children delivered before 32 weeks of gestation due to suspected FGR and/or maternal hypertensive disorder who survived until 2 years of age, prenatal ARED in the umbilical artery was associated with a higher incidence of severe or moderate neuromotor and/or sensory disability. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Planned delivery route of preterm breech singletons, and neonatal and 2-year outcomes: a population-based cohort study.

OBJECTIVE: To assess whether planned route of delivery is associated with perinatal and 2-year outcomes for preterm breech singletons. DESIGN: Prospective nationwide population-based EPIPAGE-2 cohort study. SETTING: France, 2011. SAMPLE: Three hundred and ninety women with breech singletons born at 26-34 weeks of gestation after preterm labour or preterm prelabour rupture of membranes. METHODS: Propensity-score analysis. MAIN OUTCOME MEASURES: Survival at discharge, survival at discharge without severe morbidity, and survival at 2 years of corrected age without neurosensory impairment. RESULTS: Vaginal and caesarean deliveries were planned in 143 and 247 women, respectively. Neonates with planned vaginal delivery and planned caesarean delivery did not differ in survival (93.0 versus 95.7%, P = 0.14), survival at discharge without severe morbidity (90.4 versus 89.9%, P = 0.85), or survival at 2 years without neurosensory impairment (86.6 versus 91.6%, P = 0.11). After applying propensity scores and assigning inverse probability of treatment weighting, as compared with planned vaginal delivery, planned caesarean delivery was not associated with improved survival (odds ratio, OR 1.31; 95% confidence interval, 95% CI 0.67-2.59), survival without severe morbidity (OR 0.75, 95% CI 0.45-1.27), or survival at 2 years without neurosensory impairment (OR 1.04, 95% CI 0.60-1.80). Results were similar after matching on propensity score. CONCLUSIONS: No association between planned caesarean delivery and improved outcomes for preterm breech singletons born at 26-34 weeks of gestation after preterm labour or preterm prelabour rupture of membranes was found. The route of delivery should be discussed with women, balancing neonatal outcomes with the higher risks of maternal morbidity associated with caesarean section performed at low gestational age.

Cephalad-caudad vs transverse blunt expansion of low transverse hysterotomy during caesarean section and risk of severe postpartum haemorrhage: A prospective comparative study.

BACKGROUND: The global prevalence of caesarean section as a delivery method is increasing worldwide. However, there is notable divergence among countries in their national guidelines regarding the optimal technique for blunt expansion hysterotomy of the low transverse uterine incision during caesarean section (cephalad-caudad or transverse). AIM: To compare the risk of severe postpartum haemorrhage (PPH) between cephalad-caudad and transverse blunt expansion hysterotomy during caesarean section. METHODS: This prospective comparative observational study was conducted in a university maternity hospital. All women who gave birth to one infant by caesarean section after 30 weeks of gestation between November 2020 and November 2021 were included in this study. The exclusion criteria were a coagulation disorder, the presence of placenta previa, multiple pregnancies, or enlargement of the hysterotomy with scissors. The choice between cephalad-caudad or transverse blunt expansion of the low transverse hysterotomy was left to the surgeon's discretion. The primary outcome measure was severe PPH, defined as estimated blood loss ≥ 1000 ml. Univariate and multivariate analyses were employed to assess the risk of severe PPH associated with the two methods of enlarging the low transverse hysterotomy. RESULTS: The study included 850 women, of whom 404 underwent transverse blunt expansion and 446 underwent cephalad-caudad blunt expansion. The overall incidence of severe PPH was 13.3 %. Univariate analysis revealed no significant difference in the frequency of severe PPH between the cephalad-caudad and transverse blunt expansion groups (13.9 % vs 12.6 %; p = 0.61). However, the use of additional surgical sutures (mainly additional haemostatic stitches) was less common with cephalad-caudad blunt expansion (26.7 % vs 36.9 %; p < 0.05). Multivariate analysis showed no significant difference in risk between the two techniques (odds ratio 1.17, 95 % confidence interval 0.77-1.78). CONCLUSION: No significant difference in the risk of severe PPH was found between cephalad-caudad and transverse blunt expansion of the low transverse hysterotomy during caesarean section.

[Intrahepatic cholestasis of pregnancy: French College of Obstetricians and Gynecologists guidelines for clinical practice]. / La cholestase gravidique : recommandations pour la pratique clinique du Collège national des gynécologues obstétriciens français.

OBJECTIVE: To identify strategies for reducing neonatal and maternal morbidity associated with intrahepatic cholestasis pregnancy (ICP). MATERIAL AND METHODS: The quality of evidence of the literature was assessed following the GRADE methodology with questions formulated in the PICO format (Patients, Intervention, Comparison, Outcome) and outcomes defined a priori and classified according to their importance. An extensive bibliographic search was performed on PubMed, Cochrane, EMBASE and Google Scholar databases. The quality of the evidence was assessed (high, moderate, low, very low) and a (i) strong or (ii) weak recommendations or (iii) no recommendation were formulated. The recommendations were reviewed in two rounds with external reviewers (Delphi survey) to select the consensus recommendations. RESULTS: Of the 14 questions (from 12 PICO questions and one definition question outside the PICO format), there was agreement between the working group and the external reviewers on 14 (100%). The level of evidence of the literature was insufficient to provide a recommendation on two questions. ICP is defined by the occurrence of suggestive pruritus (palmoplantar, nocturnal) associated with a total bile acid level>10µmol/L or an alanine transaminase level above 2N after ruling out differential diagnoses. In the absence of suggestive symptoms of a differential diagnosis, it is recommended not to carry out additional biological or ultrasound tests. In women with CIP, ursodeoxycholic acid is recommended to reduce the intensity of maternal pruritus (Strong recommendation. Quality of the evidence moderate) and to decrease the level of total bile acids and alanine transaminases. (Strong recommendation. Quality of the evidence moderate). S-adenosyl-methionine, dexamethasone, guar gum or activated charcoal should not be used to reduce the intensity of maternal pruritus (Strong recommendation. Quality of evidence low), and there is insufficient data to recommend the use of antihistamines (No recommendation. Quality of evidence low). Rifampicin (Weak recommendation. Very low quality of evidence) or plasma exchange (Strong recommendation. Very low quality of evidence) should not be used to reduce maternal pruritus and perinatal morbidity. Serum monitoring of bile acids is recommended to reduce perinatal morbidity and mortality (stillbirth, prematurity) (Low recommendation. Quality of the evidence low). The level of evidence is insufficient to determine whether fetal heart rate or fetal ultrasound monitoring are useful to reduce perinatal morbidity (No recommendation). Birth is recommended when bile acid level is above 99µmol/L from 36 weeks gestation to reduce perinatal morbidity, in particular stillbirth. When bile acid level is above 99µmol/L is below 100µmol/L, women should be informed that induction of labor could be considered 37 and 39 weeks gestation to reduce perinatal morbidity. (Strong recommendation. Quality of evidence low). In postpartum, total bile acids and alanine transaminases level should be checked and normalized before prescribing estrogen-progestin contraception, ideally with a low estrogen dose (risk of recurrence of pruritus and cytolysis) (Low recommendation. Quality of evidence very low). CONCLUSION: Although the quality of evidence regarding ICP gestational cholestasis remains low, there is a strong consensus in France, as shown by our Delphi study, on how to manage women with ICP. The reference first-line treatment is ursodeoxycholic acid.

[Modalities of birth in case of uncomplicated preterm premature rupture of membranes: CNGOF Preterm Premature Rupture of Membranes Guidelines]. / Modalités de naissance en cas de rupture des membranes avant terme non compliquée. RPC Rupture prématurée des membranes avant terme CNGOF.

OBJECTIVE: To identify the ideal gestational age at delivery for preterm premature rupture of membranes and modalities of birth. METHOD: To identify studies, research was conducted using Pub-Med, Embase and Cochrane databases. RESULTS: Prolonged latency duration after pPROM does not worsen neonatal prognosis (NP3). Therefore, it is recommended not to deliver before 34 weeks of gestation for patient with uncomplicated preterm rupture of membranes (pPROM) (Grade C). After 34 weeks of gestation, expectant management for pPROM is not associated with neonatal sepsis (NP1) but is associated to intra-uterine infection (NP2). Early delivery is associated with higher risk of respiratory distress syndrome (NP2), higher risk of cesarean section (NP2) and longer duration of NICU hospitalization (NP2). Before 37 weeks of gestation, expectant management is recommended for uncomplicated pPROM (Grade A), even if vaginal group B streptococcus is positive, as long as antibiotics are used at the time of membranes rupture (Professional consensus). Elective cesarean section is reserved for usual obstetrical indications. Oxytocin and prostaglandins are reasonable options for inducing labor (Professional consensus). Data are too scarce to establish recommendation regarding intra-cervical balloons in case of pPROM (Professional consensus). CONCLUSION: Expectant management is recommended for uncomplicated pPROM before 37 weeks of gestation.

Growth and shape of a laboratory alluvial fan.

Using laboratory experiments, we investigate the influence of water and sediment discharges on the morphology of an alluvial fan. In our flume, a single-thread laminar river deposits corundum sand into a conical fan. We record the fan progradation with top-view images and measure its shape using the deformation of a Moiré pattern. The fan remains virtually self-affine as it grows, with a nearly constant slope. We find that, when the sediment discharge is small, the longitudinal slope of the fan remains close to that of a river at the threshold for sediment transport. Consequently the slope depends on the water discharge only. A higher sediment discharge causes the fan's slope to depart from the threshold value. Due to the downstream decrease of the sediment load, this slope gets shallower towards the fan's toe. This mechanism generates a concave fan profile. This suggests that we could infer the sediment flux that feeds a fan based on its proximal slope.

[Preterm premature rupture of membranes: CNGOF Guidelines for clinical practice - Short version]. / Rupture prématurée des membranes avant terme : recommandations pour la pratique clinique du CNGOF ­ Texte court.

OBJECTIVE: To determine management of women with preterm premature rupture of membranes (PPROM). METHODS: Bibliographic search from the Medline and Cochrane Library databases and review of international clinical practice guidelines. RESULTS: In France, PPROM rate is 2 to 3% before 37 weeks of gestation (level of evidence [LE] 2) and less than 1% before 34 weeks of gestation (LE2). Prematurity and intra-uterine infection are the two major complications of PPROM (LE2). Compared to other causes of prematurity, PPROM is not associated with an increased risk of neonatal mortality and morbidity, except in case of intra-uterine infection, which is associated with an augmentation of early-onset neonatal sepsis (LE2) and of necrotizing enterocolitis (LE2). PPROM diagnosis is mainly clinical (professional consensus). In doubtful cases, detection of IGFBP-1 or PAMG-1 is recommended (professional consensus). Hospitalization of women with PPROM is recommended (professional consensus). There is no sufficient evidence to recommend or not recommend tocolysis (grade C). If a tocolysis should be prescribed, it should not last more than 48hours (grade C). Antenatal corticosteroids before 34 weeks of gestation (grade A) and magnesium sulfate before 32 weeks of gestation (grade A) are recommended. Antibiotic prophylaxis is recommended (grade A) because it is associated with a reduction of neonatal mortality and morbidity (LE1). Amoxicillin, 3rd generation cephalosporins, and erythromycin in monotherapy or the association erythromycin-amoxicillin can be used (professional consensus), for 7 days (grade C). However, in case of negative vaginal culture, early cessation of antibiotic prophylaxis might be acceptable (professional consensus). Co-amoxiclav, aminosides, glycopetides, first and second generation cephalosporins, clindamycin, and metronidazole are not recommended for antibiotic prophylaxis (professional consensus). Outpatient management of women with clinically stable PPROM after 48hours of hospitalization is a possible (professional consensus). During monitoring, it is recommended to identify the clinical and biological elements suggesting intra-uterine infection (professional consensus). However, it not possible to make recommendation regarding the frequency of this monitoring. In case of isolated elevated C-reactive protein, leukocytosis, or positive vaginal culture in an asymptomatic patient, it is not recommended to systematically prescribe antibiotics (professional consensus). In case of intra-uterine infection, it is recommended to immediately administer an antibiotic therapy associating beta-lactamine and aminoside (grade B), intravenously (grade B), and to deliver the baby (grade A). Cesarean delivery should be performed according to the usual obstetrical indications (professional consensus). Expectative management is recommended before 37 weeks of gestation in case of uncomplicated PPROM (grade A), even in case of positive vaginal culture for B Streptococcus, provided that an antibiotic prophylaxis has been prescribed (professional consensus). Oxytocin and prostaglandins are two possible options to induce labor in case of PPROM (professional consensus). CONCLUSION: Expectative management is recommended before 37 weeks of gestation in case of uncomplicated PPROM (grade A).

[Does post operative sonographic position of preventive cervical cerclage affect gestational age at birth?] / La position du cerclage préventif à l'échographie postopératoire est-elle prédictive d'un accouchement prématuré ?

OBJECTIVE: To evaluate whether the position of preventive cerclage determined by immediate postoperative transvaginal cervical ultrasound is predictive of preterm birth. METHODS: A single-center retrospective study conducted between 1 August 2007 and 31 December 2015 in a maternity type III who included women carrying out for a single pregnancy and who receive a McDonald preventive cerclage. Measurements of internal os-stitch, stitch-external os and the total length of the cervix were performed during immediate postoperative transvaginal cervical ultrasound. The position of the cerclage has been defined by the internal os-stitch/cervical length and stitch-external os/cervical length ratios. Measures were compared according to gestational age at delivery (before and after 32weeks and before and after 37weeks). RESULTS: During the study period, 379 single pregnancies that received a McDonald preventive cerclage were included. The mean gestational age at delivery was 37.6±3.6 SA. The rate of preterm birth before 32weeks was 6.5% (n=25) and before 37weeks was 16.6% (n=63). There was no significant difference in the internal ost-stitch/cervical length ratios and the stitch-external ost/cervical length ratio between women who delivered before and after 32weeks or for those who delivered before and after 37weeks. The areas under the ROC curves for the various parameters studied were all less than or equal to 0.6. CONCLUSIONS: The position of cerclage determined by transvaginal cervical ultrasound in immediate post operative does not seem predictive of the risk of premature birth.

Pressure-induced inactivation of E. coli beta-galactosidase: influence of pH and temperature.

In order to assess the feasibility of a high-pressure immunodesorption process using a beta-galactosidase-anti-beta-galactosidase complex as a model, the influence of high hydrostatic pressure on the activation of E. coli beta-galactosidase has been investigated. The irreversible activity loss of beta-galactosidase was studied as a function of pH and temperature for pressures comprised between atmospheric pressure and 500 megapascal (MPa; 1 MPa = 10 bar). This enabled us to establish a practical pressure-temperature diagram of stability for this enzyme. The stability domains determined thus appeared to be strongly dependent on the pH under atmospheric pressure of phosphate buffer employed for pressurisation. Therefore, to interpret meaningfully this result, the influence of pressure on the pH-activity curve of beta-galactosidase was investigated by using a high-pressure stopped-flow device. It appeared that the pH-activity curve of this enzyme was also reversibly affected by pressures lower than 150 MPa. An interpretation of these results in relation to the high-pressure induced changes of ionisation constants is proposed. For our practical purpose, the implications for the elaboration of a high-pressure immunodesorption process using beta-galactosidase as a tag, are discussed.

In vitro adhesion of human epidermal Langerhans cells to laminin and fibronectin occurs through beta 1 integrin receptors.

Human epidermal Langerhans cells are dendritic cells that can capture, process, and present antigens to T cells. It was previously shown that these Langerhans cells express the very late activation antigen (VLA) protein family of beta 1 integrins. beta 1 integrins mainly mediate the adhesion of cells to a number of extracellular components, such as laminin, fibronectin, and collagen, which are present in the skin. In this report, we demonstrate that a large percentage of the Langerhans cell population was able in vitro to attach to laminin and fibronectin but not to collagen. An ultrastructural study of adherent Langerhans cells showed that they were spread largely on laminin, with a loss of their round shape, and partially on fibronectin. Langerhans cell binding to laminin or fibronectin induced a decrease of the Birbeck granule number. Specific inhibitions of cell adhesion were performed, and it was demonstrated that VLA-6 was the major receptor involved in Langerhans cell adhesion to laminin. This adhesion was not RGD dependent and was slightly enhanced by Mn2+. VLA-3 and especially VLA-5 mediated Langerhans cell binding to fibronectin through the RGDS sequence of the protein. Mn2+ sharply increased the Langerhans cell adhesion to fibronectin. VLA-6 mediated in vitro Langerhans cell adhesion to laminin, which suggests that in vivo VLA-6 could permit Langerhans cells to attach and migrate through the basement membrane. Moreover, VLA-5 and VLA-3 take part in the in vitro Langerhans cell binding to fibronectin, suggesting that in vivo these fibronectin receptors could facilitate Langerhans cell passage throughout the fibronectin network of the dermis before migration to lymph nodes.

[Efficiency and tolerance of calcium channel blockers as first-line tocolysis]. / Efficacité et tolérance des inhibiteurs calciques en tocolyse.

Calcium channel blockers are widely used as first-line tocolytic, but prescribed off-label for this indication. The primary objective of this review is to evaluate the efficiency and safety of calcium channel blockers compared to placebo and to all tocolytic agents used. This review concerns the randomized trials, comparative studies and meta-analyzes of randomized trials on the subject. Nifedipine is superior to placebo in reducing the risk of delivery within 48 hours (RR=0.3; 95 % CI [0.21-0.43]), but induces more maternal side effects (RR=3.8; 95 % CI [1.02-16.92]). The effectiveness of nifedipine is greater than that of betamimetics to prolong pregnancy beyond 48 hours (OR=1.52; 95 % CI [1.03-2.24]), and up to 34 weeks (OR=1.87; 95 % CI [1.11-3.15]), with a lower incidence of adverse events requiring discontinuation of treatment in case of use of nifedipine (RR=0.22; 95 % CI [0.10-0.48]), but no significant difference in neonatal mortality. Efficacy of nifedipine is similar to that of oxytocin antagonists to prolong pregnancy beyond 48 hours (RR=0.92; 95 % CI [0.37-2.30]), but causes more mild maternal adverse events (RR=2.61, 95 % CI [1.43-4.74]). Nicardipine is not evaluated as nifedipine as a tocolytic treatment. It appears as effective as salbutamol and appears to have fewer maternal side effects than IV salbutamol.

[Epidemiology of shoulder dystocia]. / Épidémiologie de la dystocie des épaules.

OBJECTIVES: To synthetize the available evidence regarding the incidence and risk factors of shoulder dystocia (SD). METHODS: Consultation of the Medline database, and of national guidelines. RESULTS: Shoulder dystocia is defined as a vaginal delivery that requires additional obstetric manoeuvres to deliver the foetus after the head has delivered and gentle traction has failed. With this definition, the incidence of SD in population-based studies is about 0.5-1% of vaginal deliveries. Many risk factors have been described but most associations are not independent, or have not been constantly found. The 2 characteristics consistently found as independent risk factors for SD in the literature are previous SD (incidence of SD of about 10% in parturients with previous SD) and foetal macrosomia. Maternal diabetes and obesity also are associated with a higher risk of SD (2 to 4 folds) but these associations may be completely explained by foetal macrosomia. However, even factors independently and constantly associated with SD do not allow a valid prediction of SD because they are not discriminant; 50 to 70% of SD cases occur in their absence, and the great majority of deliveries when they are present is not associated with SD. CONCLUSION: Shoulder dystocia is defined by the need for additional obstetric manoeuvres to deliver the foetus after the head has delivered and gentle traction has failed, and complicates 0.5-1% of vaginal deliveries. Its main risk factors are previous SD and macrosomia, but they are poorly predictive. SD remains a non-predictable obstetrics emergency. Knowledge of SD risk factors should increase the vigilance of clinicians in at-risk contexts.

Human epidermal Langerhans cells express integrins of the beta 1 subfamily.

The expression of VLA integrins on human epidermal Langerhans cells (LC) was investigated by indirect immunogold labeling on transmission electron microscopy, followed by a quantitative analysis. Labelings on suspensions enriched in freshly isolated LC were carried out with an antibody recognizing the beta 1 subunit, common to all members of the VLA family, and with antibodies specific for the six different alpha subunits, alpha 1 to alpha 6. Normal human epidermal LC were all beta 1 positive, of which 60% were highly positive. By labelings with different VLA-alpha-chain MoAb, there appeared two subpopulations of LC: one positive and one negative. On average 40% of LC bore small amounts of VLA-1 and VLA-3, 53% and 77% of LC expressed moderate amounts of VLA-2 and VLA-5, respectively, and VLA-4 and VLA-6 were expressed by 67% and 90% of LC, respectively. VLA proteins are mainly extracellular matrix protein receptors. VLA-6 (laminin receptor) and VLA-5 (fibronectin receptor) are expressed mainly by LC, and in this way could subserve LC to leave the epidermal compartment through the basement membrane, to migrate throughout the fibronectin network of the dermis before migrating via the afferent lymphatics to the regional lymph nodes, where they present antigen to T cells. VLA proteins such as VLA-4, VLA-3, or VLA-2, which are found involved in cell-cell contacts, could contribute to the promotion of T-cell activation by facilitating adherence between LC and T cells.

In vitro HIV-1 entry and replication in Langerhans cells may clarify the HIV-1 genome detection by PCR in epidermis of seropositive patients.

Being dendritic antigen-presenting cells in skin and mucous membrane, Langerhans cells (LC) occur in areas at risk for inoculation by human immunodeficiency virus (HIV), and the question whether LC act as a target, reservoir, or vector for transmission of HIV has given rise to much controversy. To address this question, we first analyzed the epidermal compartment of skin from patients seropositive for HIV DNA. Second, we tested the susceptibility of each cell type normally found in this compartment to in vitro infection by HIV-1. A non-denatured DNA was obtained from epidermal sheets after a thermochemical treatment of biopsies (0.5 M ethylenediaminetetraacetic acid (EDTA), pH 7.5 at 60 degrees C for 90 seconds). Optimization of amplification of viral genome was performed with three primer pairs derived from gag, env, and pol sequences. Polymerase chain reaction (PCR) products were analyzed by Southern blot. Viral genome was found in five of 11 HIV-seropositive patients. To control the permissivity of epidermal cell population for HIV, cells isolated from the epidermal sheet of normal skin by trypsinization were co-cultured with HIV-1-carrying promonocytic cells (U937) and observed by electron microscopy. After 3-6 h of co-culture, numerous virions were either tightly bound or apparently engaged in the process of internalization through receptor-mediated endocytosis. At day 4 of co-culture, some infected LC appeared to release mature viral particles through bud formation. The in vitro HIV-1 entry and replication in LC may confirm the presence of the HIV-1 genome by PCR in epidermis of seropositive patients. The consequences of the permissivity of LC for HIV on the antigen-presenting function remain to be determined.

Glycogen synthesis and immunocytochemical study of fructose-1,6-biphosphatase in methionine sulfoximine epileptogenic rodent brain.

The effects of the convulsant methionine sulfoximine (MSO) on the glucose pathway have been investigated in mouse and rat brain. The key gluconeogenic enzyme fructose-1,6-biphosphatase (FBPase) (EC 3.1.3.11) was immunostained by rat anti-FBPase antibody. The rat cortex slices were very lightly stained, almost unstained in controls. After MSO injection, there was a marked staining only in astrocytes (perikarya, processes, and end feet). The activity of this enzyme also increased. MSO induced an increase of 63% in the stability at heating (47 degrees C) and of 36% in the stability at proteolysis (trypsin, 10 micrograms/ml) of FBPase. The convulsant had no effect on the concentrations of the metabolites related to the FBPase-phosphofructokinase step, i.e., fructose-1,6-biphosphate, glyceraldehyde-3-phosphate, and dihydroxyacetone phosphate, before, during, or after the convulsions. These results show that the cellular site of glucose pathway impairment induced by MSO in rodent brain is presumably the astroglial cells and that one mechanism of glycogenesis could be the reinforcement of the molecules of FBPase, which enhances gluconeogenesis. A hypothetical diagram of glucose metabolism under the effect of MSO has been proposed.

Kinetic study of esterification by immobilized lipase in n-hexane.

The kinetic of the esterification of oleic acid by ethanol catalyzed by immobilized lipase of Mucor miehei in n-hexane as a solvent has been completely studied. The kinetics of the reaction are suggested to agree with a Ping-Pong Bi Bi mechanism in which only inhibition by excess of ethanol has been identified. Values of all apparent kinetic parameters were computed. No evidence of any significant external diffusional limitation which could account for these values has been detected. Optimization of water content through distribution ratio of water between solvent and support was examined.

Subcellular distribution of cytochrome c oxidase, monoamine oxidase and lactate dehydrogenase in the developing chick telencephalon.

The distribution of cytochrome c oxidase monoamine oxidase and lactate dehydrogenase, together with protein, after isopycnic centrifugation of a crude mitochondrial fraction of chick telencephalon homogenate in a linear sucrose density gradient, was followed during late embryogenesis and postnatal maturation. Two main populations of subcellular organelles differentiate; they were characterized biochemically and analyzed by electron microscopy. One population, with a progressively defined mean buoyant density of 1.170 g/ml, exhibited a high relative activity of monoamine oxidase, with a low and relatively constant cytochrome c oxidase/monoamine oxidase activity ratio. This population was composed of free mitochondria and mitochondria enclosed in nerve endings, and possibly of mitochondria of perikaryal and glial origin. A second population, with a progressively well defined mean buoyant density of 1.182-1.186 g/ml, exhibited a high relative activity of cytochrome c oxidase, with a high and increasing cytochrome c oxidase/monoamine oxidase activity ratio. The biochemical and functional significance of these results were discussed.