[Thrombosis risk during pregnancy after history of cerebral venous thrombosis]

INTRODUCTION

Few data have been published about the prognosis of a pregnancy following an episode of venous cerebral thrombosis (CVT), and far less about preventive strategy.

METHODS

This is a retrospective study of a case series of 11 pregnancies in six women who had previously presented a CVT.

RESULTS

The first pregnancies after CVT occurred on average 58 months later. Prevention with aspirin or heparin was administered in ten cases during pregnancy, and in all the cases with heparin in postpartum. No recurrence of CVT was observed. A minor pulmonary embolism was diagnosed in postpartum in one case.

CONCLUSION

Prognosis of a pregnancy after a CVT seems to be favourable if a sufficient delay after CVT is respected. Although no results of controlled trials are available, prophylaxis with heparin is probably reasonable as benefit seems higher than risks and is strongly advised during the postpartum period.

Bell's palsy in pregnancy: underlying HELLP syndrome or pre-eclampsia?

Bell's palsy is not uncommon during pregnancy. An association with pre-eclampsia (PE) has been reported previously. Furthermore, it has even been suggested that Bell's palsy could be a predictor of PE. We report three cases illustrating various possible aspects of this association, one of them including the features of HELLP (haemolysis, elevated liver enzymes, and low platelets) syndrome.

[Severe neonatal acidosis: comparison and analysis of obstetrical practices in two French perinatal centers]

OBJECTIVES

To identify and compare risk factors for severe neonatal acidosis, defined by an umbilical artery pH inferior to 7.00, and clinical practices in two different perinatal centers.

PATIENTS AND METHODS

In a retrospective study, from 2003 to 2008, in two university perinatal centers (Poitiers and Saint-Antoine in Paris) on all term pregnancies complicated by severe neonatal acidosis (umbilical artery pH<7.00), we elected to compare the following risk factors: maternal characteristics, medical and obstetrical histories, progress of pregnancy, labour and delivery as well as the neonatal status.

RESULTS

Among 23,508 births, 177 term newborns had severe neonatal acidosis. The rate was similar for both perinatal centers of Poitiers and Saint-Antoine (0.92% and 0.77% respectively). Factors associated with severe neonatal acidosis were similar in both centers: maternal age, thick meconium, prior cesarean section. There were differences in obstetrical practices between the two centers: there were more caesarean sections and assisted vaginal deliveries in Paris and more inductions of labour in Poitiers.

CONCLUSION

Severe neonatal acidosis is associated with the geographical origin, the progress of labour and the mode of delivery. It seems that severe neonatal acidosis is unrelated to cesarean delivery.

Tomonaga-Luttinger physics in electronic quantum circuits

In one-dimensional conductors, interactions result in correlated electronic systems. At low energy, a hallmark signature of the so-called Tomonaga–Luttinger liquids is the universal conductance curve predicted in presence of an impurity. A seemingly different topic is the quantum laws of electricity, when distinct quantum conductors are assembled in a circuit. In particular, the conductances are suppressed at low energy, a phenomenon called dynamical Coulomb blockade. Here we investigate the conductance of mesoscopic circuits constituted by a short single-channel quantum conductor in series with a resistance, and demonstrate a proposed link to Tomonaga–Luttinger physics. We reformulate and establish experimentally a recently derived phenomenological expression for the conductance using a wide range of circuits, including carbon nanotube data obtained elsewhere. By confronting both conductance data and phenomenological expression with the universal Tomonaga–Luttinger conductance curve, we demonstrate experimentally the predicted mapping between dynamical Coulomb blockade and the transport across a Tomonaga–Luttinger liquid with an impurity.

When physicists study the characteristics of quantum conductors they usually take great pains to limit the resistance of other elements in the system. But Jezouin et al. show that when a single quantum channel is measured in series with a resistor, it exhibits analogous characteristics to a Tomonaga–Luttinger liquid.

Chargeless heat transport in the fractional quantum Hall regime

We demonstrate a direct approach to investigate heat transport in the fractional quantum Hall regime. At a filling factor of ν=4/3, we inject power at quantum point contacts and detect the related heating from the activated current through a quantum dot. The experiment reveals a chargeless heat transport from a significant heating that occurs upstream of the power injection point, in the absence of a concomitant electrical current. By tuning in situ the edge path, we show that the chargeless heat transport does not follow the reverse direction of the electrical current path along the edge. This unexpected heat conduction, whose mechanism remains to be elucidated, may play an important role in the physics of the fractional quantum Hall regime.

Quantum coherence engineering in the integer quantum Hall regime

We present an experiment where the quantum coherence in the edge states of the integer quantum Hall regime is tuned with a decoupling gate. The coherence length is determined by measuring the visibility of quantum interferences in a Mach-Zehnder interferometer as a function of temperature, in the quantum Hall regime at a filling factor 2. The temperature dependence of the coherence length can be varied by a factor of 2. The strengthening of the phase coherence at finite temperature is shown to arise from a reduction of the coupling between copropagating edge states. This opens the way for a strong improvement of the phase coherence of quantum Hall systems. The decoupling gate also allows us to investigate how interedge state coupling influences the quantum interferences' dependence on the injection bias. We find that the finite bias visibility can be decomposed into two contributions: a Gaussian envelope which is surprisingly insensitive to the coupling, and a beating component which, on the contrary, is strongly affected by the coupling.

Indication of electron neutrino appearance from an accelerator-produced off-axis muon neutrino beam

The T2K experiment observes indications of ν(μ) → ν(e) appearance in data accumulated with 1.43×10(20) protons on target. Six events pass all selection criteria at the far detector. In a three-flavor neutrino oscillation scenario with |Δm(23)(2)| = 2.4×10(-3)  eV(2), sin(2)2θ(23) = 1 and sin(2)2θ(13) = 0, the expected number of such events is 1.5±0.3(syst). Under this hypothesis, the probability to observe six or more candidate events is 7×10(-3), equivalent to 2.5σ significance. At 90% C.L., the data are consistent with 0.03(0.04) < sin(2)2θ(13) < 0.28(0.34) for δ(CP) = 0 and a normal (inverted) hierarchy.

[Medical assessment after a pre-eclampsia: why? for whom? when? how? for what purpose?]

The internist has a relevant role in the medical assessment which is mandatory after every case of pre-eclampsia. This postnatal visit has to be performed to assert there is no underlying disorder such as chronic arterial hypertension or nephropathy, autoimmune disease or thrombophilia. This visit is also needed to provide information to the woman about what occurred during the pregnancy as well as to consider which would have to be done in case of a subsequent pregnancy. Long-term outcome had also to be taken into account considering risks for cardiac, arterial, renal and metabolic diseases. This visit is of outmost importance after very early-onset pre-eclampsia, and especially if it has already occurred. The postnatal visit after pre-eclampsia represents a very demonstrative example of the role that the internist can afford to the obstetrician in the management of medical disorders occurring during pregnancy and needing a specific expertise as well as a long-term follow-up.

Tuning energy relaxation along quantum Hall channels

The chiral edge channels in the quantum Hall regime are considered ideal ballistic quantum channels, and have quantum information processing potentialities. Here, we demonstrate experimentally, at a filling factor of ν(L)=2, the efficient tuning of the energy relaxation that limits quantum coherence and permits the return toward equilibrium. Energy relaxation along an edge channel is controllably enhanced by increasing its transmission toward a floating Ohmic contact, in quantitative agreement with predictions. Moreover, by forming a closed inner edge channel loop, we freeze energy exchanges in the outer channel. This result also elucidates the inelastic mechanisms at work at ν(L)=2, informing us, in particular, that those within the outer edge channel are negligible.

Energy relaxation in the integer quantum Hall regime

We investigate the energy exchanges along an electronic quantum channel realized in the integer quantum Hall regime at a filling factor of νL=2. One of the two edge channels is driven out of equilibrium and the resulting electronic energy distribution is measured in the outer channel, after several propagation lengths 0.8  μm≤L≤30  μm. Whereas there are no discernible energy transfers toward thermalized states, we find efficient energy redistribution between the two channels without particle exchanges. At long distances L≥10  μm, the measured energy distribution is a hot Fermi function whose temperature is lower than expected for two interacting channels, which suggests the contribution of extra degrees of freedom. The observed short energy relaxation length challenges the usual description of quantum Hall excitations as quasiparticles localized in one edge channel.

[Late prognosis after preeclampsia]

Preeclampsia, eclampsia and HELLP syndrome are severe complications of pregnancy associated with a high morbidity and mortality for both mother and foetus. The issue of prognosis with regards to risk of relapse is therefore of upmost importance for both the patients and doctors managing their subsequent pregnancies. The overall risk of relapse is estimated to be less than 10%. The risk is especially increased in case of early onset, before the 28(th) week of amenorrhea. In such patients, an underlying renal disease, essential hypertension or secondary hypertension might be identified. A renal consultation must ensure the complete resolution of the hypertension and proteinuria, otherwise investigations need to be carried out looking for an underlying renal or vascular disease affecting the renal parenchyma or outflow. Screening for a hereditary thrombophilia is performed in the immediate post-partum period following and early onset PE, especially if associated with an IUGR, fetal death, or in an early and severe relapse. A renal biopsy is only rarely considered: it is either performed within the first post-partum days whenever a systemic disease flare-up is suspected (i.e. SLE), or late if the proteinuria failed to settle beyond 6 months post-part. Severe PE is a marker of a vascular disease of short duration, but must be considered a risk factor for later atherosclerosis with cardiovascular complications, justifying long term cardiovascular, renal and metabolic follow-up.

[Recommendations for medical management of women with preeclampsia]

When analyzing various recommendations formulated by the colleges of specialty, as well as precedents, the following guidelines can be formulated with respect to communication as part to the management of PE. These guidelines affect the professionals & the pregnant women within a healthcare network. Recommendations destined to the former include: Recommendations destined to the latter include:

[Informing a patient about surgical treatment for pelvic organ prolapse]

Inform consent is a major objective in the relation patient-physician. Patient's information becomes doubt when it is insufficient. To answer to medical persons asking about patient's information, pretreatment clinical and paraclinical assessment will be discussed. Reflexion delay, surgical alternative therapy and pre-operatory examination will be exposed. Several critical situations, such as associated hysterectomy, patient's comorbidity (tobacco, obesity) or synthetic mesh reinforcement have to be well-known to inform patient about failures and outcomes.

Botulism and hot-smoked whitefish: a family cluster of type E botulism in France, September 2009

A family cluster of three cases of type E botulism were identified in south-east France in September 2009. The suspected food source of infection was a vacuum packed hot-smoked whitefish of Canadian origin purchased by the family during a visit to Finland and consumed several weeks later in France on the day prior to symptom onset. No leftover fish was available to confirm this hypothesis. Vacuum packed hot-smoked whitefish has previously been associated with cases of type E botulism in multiple countries, including Finland, Germany, the United States and Israel.

[Very preterm birth: is maternal anesthesia a risk factor for neonatal intubation in the delivery room?]

OBJECTIVE

To assess the risk of tracheal intubation at birth in very premature neonates related to the type of maternal anesthesia in case of elective cesarean.

POPULATION AND METHODS

All 219 live-born very premature neonates (28-32 weeks of gestation), delivered after an elective cesarean in the 27 maternity wards of 2 French semi-rural neonatal networks. Eighty-three percent (182/219) were delivered in level III maternity wards in university hospitals.

RESULTS

Of the very preterm neonates, 33.3% (73/219) were intubated in the delivery room, either for respiratory distress syndrome or a low APGAR score. Very preterm neonates delivered after maternal general anesthesia were more often intubated than those delivered after spinal anesthesia (48.7% vs 25.2%; OR: 2.8; 95% CI: 1.8-5.1). The risk of intubation related to maternal general anesthesia remained statistically significant after an adjustment for gestational age, fetal growth retardation, respiratory distress syndrome, type of maternity ward, and a propensity score that took into account maternal sociodemographic characteristics and the causes of very preterm birth (aOR: 3.4; 95% CI: 1.4-8.2). The risk of intubation related to general anesthesia was lower after adjusting for the 5-min APGAR score (aOR: 2.8; 95% CI: 1.0-7.3).

CONCLUSION

Very preterm neonates delivered after cesarean with general anesthesia require tracheal intubation in the delivery room more often than those delivered with spinal anesthesia. This study cannot assess a causal link between anesthesia and the need for neonatal intubation. However, neonatologists have to be aware of the type of maternal anesthesia because it may interfere with the non-invasive ventilation support policy of the very preterm neonate.

[Idiopathic intracranial hypertension and pregnancy. A report of two cases]

The authors describe two cases of idiopathic intracranial hypertension (IIH) during pregnancy. The first case was discovered in a 21-year-old primigravida at 15 weeks gestation and thereafter six evacuation lumbar punctures were necessary, and a treatment by acetazolamide, 1000mg/day, was prescribed until parturition. Labor was induced at 37 weeks for intrauterine growth retardation associated with oligohydramnios. The second patient, a 38-year-old tertigravida primipara presented clinical signs of IIH at 28 weeks gestation in the context of preterm labour after a suicide attempt by massive ingestion of venlafaxine. She was given an evacuation lumbar puncture and went into labour at 29 weeks, after tocolysis failure. The diagnosis of IIH is to be done only by exclusion, in front of a normal biological composition of the spinal fluid at lumbar puncture with increased opening pressure, and after a brain imaging excluding any expansive intracranial process or hydrocephaly. Obstetrical prognosis is usually favourable. The main complication of this pathology resides in the ocular impact. Outside pregnancy the risk factors of IIH which have been evoked are polycystic ovary syndromes and blood coagulation anomalies as thrombophilia or hypofibrinolysis. Treatment of this pathology should be medical in the first instance and surgical only in the case of resistance or for severe ocular involvement.

[Molecular biology usefulness for rapid diagnosis of Down's syndrome and common aneuploidies]

OBJECTIVE

Trisomy of chromosome 13, 18, 21 and sex chromosome aneuploidies are the most common chromosomal abnormalities encountered in prenatal screening and are responsible for polymaformative syndrome associated with severe mental retardation. This high degree of morbidity justifies the prenatal diagnosis of these aneuploidies. Fetal nuchal translucency measurement and maternal serum biochemical marker assessment are the method of choice used for antenatal screening of aneuploidies. This prenatal screening leads to numerous maternal samplings followed by karyotyping which is cost-effective, time consuming, while results are generally returned between 2 and 3 weeks. Our study describes the research of common aneuploidies by molecular biology. We have used on one hand the MLPA kit (MRC Holland) based on amplification of specific DNA probes that hybridize with chromosomes 13, 18, 21, X, Y. On the other hand we have developed multiplex fluorescent PCR, amplifying microsatellite DNA sequences.

PATIENTS AND METHODS

We have evaluated the efficiency of these two techniques to detect chromosomal abnormalities by screening 400 amniotic fluids or chorionic villi samples obtained from pregnant women presenting a high risk of chromosomal aneuploidy.

RESULTS

We have found four trisomies 21, one trisomy 13, one monosomy 13, one trisomy 18, two triploidies, one trisomy X and one Klinefelter syndrome.

DISCUSSION AND CONCLUSION

In our study we have detected by molecular biology, in less than 48 h, 100% of common chromosomal aneuploidies without false positive or false negative results which could lead molecular biology as a method of choice for the rapid detection of common aneuploidies in addition to fetal karyotyping.

Experimental test of the dynamical coulomb blockade theory for short coherent conductors

We observed the recently predicted quantum suppression of dynamical Coulomb blockade on short coherent conductors by measuring the conductance of a quantum point contact embedded in a tunable on-chip circuit. Taking advantage of the circuit modularity we measured most parameters used by the theory. This allowed us to perform a reliable and quantitative experimental test of the theory. Dynamical Coulomb blockade corrections, probed up to the second conductance plateau of the quantum point contact, are found to be accurately normalized by the same Fano factor as quantum shot noise, in excellent agreement with the theoretical predictions.

Blockade of cannabinoid CB1 receptors improves renal function, metabolic profile, and increased survival of obese Zucker rats

Obesity is a major risk factor in the development of chronic renal failure. Rimonabant, a cannabinoid CB1 receptor antagonist, improves body weight and metabolic disorders; however, its effect on mortality and chronic renal failure associated with obesity is unknown. Obese Zucker rats received either rimonabant or vehicle for 12 months and were compared to a pair-fed but untreated group of obese rats. Mortality in the obese rats was significantly reduced by rimonabant along with a sustained decrease in body weight, transient reduction in food intake, and an increase in plasma adiponectin. This was associated with significant reduction in plasma total cholesterol, low-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio, triglycerides, glucose, norepinephrine, plasminogen activator inhibitor 1, and preservation of pancreatic weight and beta-cell mass index. The cannabinoid antagonist attenuated the increase in proteinuria, urinary N-acetylglucosaminidase excretion, plasma creatinine, and urea nitrogen levels while improving creatinine clearance. Renal hypertrophy along with glomerular and tubulointerstitial lesions were reduced by rimonabant. Although the drug did not modify hemodynamics, it normalized the pressor response to angiotensin II. Our study suggests that in a rat model of chronic renal failure due to obesity, rimonabant preserves renal function and increases survival.

[Very preterm birth less than 33 weeks' gestation: how setting-up of a perinatal network does influence the activity of the neonatal tertiary care unit? The experience of the Poitou-Charentes region, France]

OBJECTIVES

To evaluate the impact of regional perinatal network setting on very preterm neonates (gestational age<33 weeks) referral and activity of regional level 3 NCIU, and short-term outcome of infants cared for.

POPULATION AND METHODS

Comparison of data from medical records of hospital days and hospital outcome of very preterm neonates born before and after the setting-up of regional perinatal network (2002-2005).

RESULTS

The setting-up of the Poitou-Charentes perinatal network has led to a 45% rise in number of very preterm neonates admitted to the level 3 neonatal care (114 in 2002, 166 in 2005), number of hospitalisation days has also increased by 31% in neonatology unit (2181 days in 2002, 2864 days in 2005) but remained stable in intensive care unit. A transient rise in neonatal mortality was observed, although the incidence of severe ultrasonographic cerebral abnormalities and that of bronchopulmonary dysplasia were lowered.

CONCLUSION

Setting-up of perinatal network in Poitou-Charentes (France) has led to improved access to level 3 neonatal care, with rise in very preterm neonates survival and low incidence of short-term sequelae.

ac Josephson effect and resonant Cooper pair tunneling emission of a single Cooper pair transistor

We measure the high-frequency emission of a single Cooper pair transistor (SCPT) in the regime where transport is only due to tunneling of Cooper pairs. This is achieved by coupling on chip the SCPT to a superconductor-insulator-superconductor junction and by measuring the photon assisted tunneling current of quasiparticles across the junction. This technique allows a direct detection of the ac Josephson effect of the SCPT and provides evidence of Landau-Zener transitions for proper gate voltage. The emission in the regime of resonant Cooper pair tunneling is also investigated. It is interpreted in terms of transitions between charge states coupled by the Josephson effect.