Designing a therapeutic hepatitis B vaccine to circumvent immune tolerance.

An effective prophylactic hepatitis B virus (HBV) vaccine has long been available but is ineffective for chronic infection. The primary cause of chronic hepatitis B (CHB) and greatest impediment for a therapeutic vaccine is the direct and indirect effects of immune tolerance to HBV antigens. The resulting defective CD4+/CD8+ T cell response, poor cytokine production, insufficient neutralizing antibody (nAb) and poor response to HBsAg vaccination characterize CHB infection. The objective of this study was to develop virus-like-particles (VLPs) that elicit nAb to prevent viral spread and prime CD4+/CD8+ T cells to eradicate intracellular HBV. Eight neutralizing B cell epitopes from the envelope PreS1 region were consolidated onto a species-variant of the HBV core protein, the woodchuck hepatitis core antigen (WHcAg). PreS1-specific B cell epitopes were chosen because of preferential expression on HBV virions. Because WHcAg and HBcAg are not crossreactive at the B cell level and only partially cross-reactive at the CD4+/CD8+ T cell level, CD4+ T cells specific for WHcAg-unique T cell sites can provide cognate T-B cell help for anti-PreS1 Ab production that is not curtailed by immune tolerance. Immunization of immune tolerant HBV transgenic (Tg) mice with PreS1-WHc VLPs elicited levels of high titer anti-PreS1 nAbs equivalent to wildtype mice. Passive transfer of PreS1 nAbs into human-liver chimeric mice prevented acute infection and cleared serum HBV from mice previously infected with HBV in a model of CHB. At the T cell level, PreS1-WHc VLPs and hybrid WHcAg/HBcAg DNA immunogens elicited HBcAg-specific CD4+ Th and CD8+ CTL responses.

[2008 update of the 8th Consensus Development Conference of the Francophone Society of Medical Emergencies of 1999. The treatment of adult renal colic by the emergency services and in emergency rooms]. / Actualisation 2008 de la 8e Conférence de consensus de la Société francophone d'urgences médicales de 1999. Prise en charge des coliques néphrétiques de l'adulte dans les services d'accueil et d'urgences.

The care in the emergencies of the renal colic at the adult was the object in 1999 of a conference of consensus of the French Society of Emergency (SFMU) in association with the French Association of Urology and the Society of Nephrology. This already former text was the object of an update in 2008 by the subcommittee of scientific monitoring of the SFMU and was presented to the congress 2008. This public presentation in the presence of an expert urologist allowed to confront this new text with the practices and to publish an updating of the conference of consensus of 1999. A survey of practice was led with the emergency physicians, whose results are presented.

[Assisted reproduction project: legal constraints, ethical considerations]. / Projet parental: contraintes légales, considérations éthiques.

The ART law on that governs the IVF assisted reproduction project in many ways seems more or less contestable from an ethical point of view, even casting doubt on the justice of the legislative measures in the hope that ethical reflection would be pursued at the institutional level as well as in clinical ethical centers, so that more human solutions can be found.

The role of the HBV envelope proteins in the HDV replication cycle.

The hepatitis delta virus (HDV) is a subviral agent that utilizes the envelope proteins of the hepatitis B virus (HBV) for propagation. When introduced into permissive cells, the HDV RNA genome replicates and associates with multiple copies of the HDV-encoded proteins to assemble a ribonucleoprotein (RNP) complex. The mechanism necessary to export the RNP from the cell is provided by the HBV envelope proteins, which have the capacity to assemble lipoprotein vesicles that bud into the lumen of a pre-Golgi compartment before being secreted. In addition to allowing the release of the HDV RNP, the HBV envelope proteins also provide a means for its targeting to an uninfected cell, thereby ensuring the spread of HDV. This chapter covers the molecular aspects of the HBV envelope protein functions in the HDV replication cycle, in particular the activity of the small envelope protein in RNP export and the function of the large envelope protein at viral entry.

Structural characterization of viral neutralizing monoclonal antibodies to hepatitis B surface antigen.

In this study we describe the viral neutralizing activity of murine monoclonal antibodies (MAb) specific for hepatitis B surface antigen (HBsAg). This viral neutralizing activity was assessed in vitro by employing Hepatitis Delta Virus (HDV) and human hepatocytes as target cells. To further characterize these viral neutralizing antibodies we generated a panel of anti-idiotypic (anti-Id) reagents and serologically characterized these antibodies for epitope specificity, Id specificity, and Id heterogeneity. Direct binding and competitive inhibition solid phase enzyme immunoassay have demonstrated that two murine MAb specific for HBsAg (anti-HBs), designated A1.2 and A3.1, recognize similar or overlapping epitopes on HBsAg, while monoclonal anti-HBs, designated A2.1 recognizes a unique HBsAg epitope. Further, Id analysis using monoclonal and polyclonal anti-Id reagents have identified both a private and a cross-reactive Id, respectively, on the anti-HBs, A1.2 preparation. The source of the idiotypic cross-reactivity between A1.2 and A3.1 has been identified, using Western blot analysis, to conformational determinants expressed by the heavy (H) and light (L) chains of these monoclonal anti-HBs. Lastly, the intrastrain antibody repertoire induced following HBsAg immunization was found to be relatively restricted in heterogeneity by clonotype analysis using isoelectric focusing and affinity immunoblot analysis. Interspecies variability in the anti-HBs response was observed based on epitope recognition using purified anti-HBs from a variety of species.

A comparison of two policies of ante-natal supervision for the prevention of prematurity.

The performance of 2 maternity units is compared. In comparable groups of average risk the prematurity rate was significantly lower in the unit practising intensive supervision during pregnancy.

In vitro culture systems for hepatitis B and delta viruses.

The development of tissue culture technology has led to invaluable information in many fields of modern virology. Until recently, the lack of an in vitro culture system for the hepatitis B virus (HBV) was a considerable impediment to the study of its life cycle at the cellular and molecular levels. However, it did not prevent its isolation and molecular cloning. Such has been the case also for the hepatitis delta virus (HDV), the genome of which was cloned and sequenced before its replication could be observed in cultured cells. In recent years, tissue culture systems for HBV and HDV have been developed progressively by the identification of permissive, established cell lines for production of virions and susceptible primary hepatocyte cultures for infection assays. I will briefly review here the recent experiments that have contributed to replicate HBV and HDV in cell culture systems.

Experimental study of cervical blockage induced by continuous low-dose oral progestogens.

An investigation correlating scanning electron microscopic observations with sperm penetration tests carried out on cervical mucus under the influence of low-dose continuous progestogen (Norgestrienone) is presented. The results demonstrate that such type of contraceptive is involved in drastic alterations of mid-cycle cervical mucus at the macromolecular level. The meshwork which constitutes the infrastructure of the cervical secretion appears to be greatly tightened as a result of the treatment, thus giving the woof a general appearance typical of cervical mucus in the late luteal phase. The immobilizing effect of such modified mucus on spermatozoa is demonstrated and the duration of effectiveness after the administration of a last pill on the morning of day 13 is determined.

PIP: The antifertility and obstructive effects toward spermatozoa of a continuous low-dose progestogen contraceptive are examined in this study. Scanning electron microscopy (SEM) observations were correlated with sperm penetration tests carried out on cervical mucus. 11 healthy women aged 19 to 36 who were using no oral contraceptives were studied for 2 consecutive cycles. During the 2nd cycle, the women took a single, daily low-dose progestogen pill (350 ug of Norgestrienone) from the 1st till the 13th day. Blood samples were collected for determination of plasma estrogen levels, which were found to be normal during the control cycle. The progestogen was found to dramatically alter midcycle cervical mucus at the macromolecular level. The meshwork constituting the infrastructure of cervical secretion appeared to be greatly tightened by the treatment, giving the woof a general appearance typical of cervical mucus in the late luteal phase. The mucus framework revealed a tangle of micelles, and sperms leaving the seminal pool in the vagina were faced with such a succession of exhausting physical obstacles that they were unable to penetrate the uterine cavity. The SEM data shows that rendering the midcycle cervical mucus hostile interferes with sperm transport and this probably accounts for the effectiveness of the continuous low-dose progestogen therapy.

Spectral analysis of fetal heart rate in flat recordings.

Flat heart rate recordings may be observed in different fetal states such as chronic distress and sleep. Their visual analysis do not allow the distinction between these two states. We used spectral analysis to study the heart rate patterns in 25 fetuses. Two significant (P < 5 x 10(-5)) groups were apparent from the determination of the position of the maximum energy peak (PMEP) in the high-frequency band (0.20-0.50 Hz): a PMEP at about 0.20 Hz (group 1), and another around 0.30 Hz (group 2). The two groups did not differ in spectral density (SD). The outcome of neonates showed that group 1 fetuses made good progress and produced healthy neonates; whereas group 2 comprised cases of chronic fetal distress, or even death in utero, and neonatal distress. The significance of this difference in PMEP between fetal heart rate patterns in chronic distress and sleep is unclear. Studies combining the assessment of fetal movements and the determination of PMEP are planned.

Prevention of perinatal consequences of pre-eclampsia with low-dose aspirin: results of the epreda trial. The Epreda Trial Study Group.

A multicentric randomized double-blind trial was realized in order to determine whether a treatment with a low-dose aspirin (150 mg/day) with or without dipyridamole (225 mg/day) was able to prevent the perinatal consequences of pre-eclampsia. This study demonstrated a significant difference in birthweight and incidence of fetal growth retardation between treatment and placebo groups. No difference was demonstrated between aspirin and aspirin + dipyridamole patients.

A case report of maternal death associated with betamimetics and betamethasone administration in premature labor.

A fatal case of pulmonary edema is reported after prolonged treatment with beta-mimetics during pregnancy for threatened premature labor. The mother had received betamethasone in order to enhance fetal lung maturity. Myocardial failure occurred 5 days after discontinuation of betamimetics. The potential toxic effects of beta-adrenergic agents and their association with corticosteroids are discussed. Caution is recommended when high doses of betamimetics are to be delivered to prevent premature labor. No patient should be treated unless her cardiac condition is normal. Cardiovascular evaluation should be regularly performed during the course of treatment. No patient should be discharged after treatment without a normal cardiovascular check-up.

Pregnancy-related changes in the distribution of glycosaminoglycans in the cervix and corpus of the human uterus.

We investigated the variations in the distribution of glycosaminoglycans (GAG) in the cervical, isthmic and corporeal stroma of the pregnant and non-pregnant human uterus. The GAG were measured in non-pregnant (n = 9) and pregnant (n = 14) cervices, in non-pregnant (n = 8) and pregnant (n = 6) uterine isthmus, and in non-pregnant (n = 12) and pregnant (n = 5) uterine corpus. Heparan sulfate is abundant in the isthmic and corporeal stroma. This has to be related to a larger content in blood vessels and muscular cells at this level than in the cervix. The distribution of hyaluronic acid and dermatan sulfate is the same in the cervix as in the corpus, but the amount of these GAGs is lower in the former, which could be due to a lower connective tissue content. Two of the main features of cervical maturation, increased hydration, and decreased dermatan sulfate concentration, were found also in the pregnant corporeal stroma. These results suggest that connective tissue maturation is not only a cervical phenomenon and could play a role in active and/or passive mechanical properties of the myometrium during late pregnancy and labor.

Comparison of vaginal examination findings in two antenatal clinics.

Findings of routine vaginal examinations during pregnancy were compared in two teaching hospitals located in the same area of Paris. We selected 2943 women who had had at least one antenatal visit between 29 and 31 weeks of gestation. Large differences in the frequency of maturation signs were observed between the two hospitals for mid-position, soft consistency and expanded lower uterine segment, although the higher frequency of each sign was not found in the same hospital. No difference was observed for dilatation of the internal os. A better reliability in assessing dilatation than other signs of maturation may explain our results and the role of dilatation in the prediction of preterm delivery.

Plasma hypoxanthine in neonatal hypoxia: a comparison of two methods.

Hypoxanthine levels were determined in both venous and arterial cord blood of 42 neonates. Two methods were compared, a PO2 electrode determination and an HPLC (high-pressure liquid chromatography) method. A good correlation was found between the two methods. However, the HPLC method was more sensitive, more reproducible and easier to perform. Hypoxanthine levels in the umbilical artery were found to be higher than in the vein. A significant negative correlation between pH and hypoxanthine level was established. The studies showed that plasma hypoxanthine levels by themselves did not provide an absolute diagnosis of intrauterine hypoxia.

Fetal growth retardation in gestational hypertension: relationships with blood pressure levels and the time of onset of hypertension.

To evaluate the effects of gestational hypertension on fetal growth, we studied the standardized records of 2996 single live-birth pregnancies. Mothers all had documented diastolic blood pressure of less than 85 mmHg before the 16th wk of amenorrhea and no history of pre-pregnancy hypertension or kidney disease. Diastolic blood pressure readings exceeding 84 mmHg were found later in pregnancy in 38.4% of the mothers, and were associated with an increased number of small-for gestational-age infants: 3.2% in mothers whose diastolic blood pressure had never reached 85 mmHg, 6.3% when peak diastolic blood pressure had been in the 85-94 mmHg range, and 8.5% when it had exceeded 94 mmHg (p less than 0.01). In mothers who had had one or more diastolic readings of more than 84 mmHg, and for all peak diastolic pressures, the rate of small-for-gestational-age infants was higher when hypertension had begun early in third trimester (between the 27th and 36th wk), than in the second trimester or later than the 35th wk (10.2% compared to 5.6 and 6.1% respectively, p = 0.02). This temporal reinforcement of the adverse fetal effects of hypertension when it began in the early third trimester was not explained by differences in the incidence of proteinuria or in maternal age, parity, obstetric history or smoking habits.

Prostaglandin E2-induced changes in the distribution of glycosaminoglycans in the isolated rat uterine cervix.

In order to study the hormonal control mechanisms of cervical ripening, we investigated the prostaglandin E2 (PGE2)-induced changes in the distribution of glycosaminoglycans (GAG) using hysterectomized and ovariectomized rats, leaving the vascularized uterine cervix in situ, as an animal model. In the first series of experiments, the GAG were measured in a control (n = 22 Wistar rats) and in a PGE2-treated group (n = 20 Wistar rats) without steroid supplementation. In the second series of experiments, the GAG were measured in a control (n = 19) and in a PGE2-treated group (n = 18) receiving estradiol and progesterone supplements. After PGE2 treatment in the two series of experiments, and despite being surgically isolated from the uterine corpus, the cervix was still able to undergo some of the structural changes associated with normal ripening (increased hydration and hyaluronic acid concentration). This suggests that PGE2, acting directly on the cervix, could be, at least in part, a modulator of biochemical events which underlie normal cervical maturation. The animal model described here seems to be suitable for studying the hormonal mechanisms of cervical ripening and the regulatory relationship between cervical maturation and myometrial contractility, which are probably subject to concordant endocrine regulation.

Quantification of the fetal heart rate variability by spectral analysis of fetal well-being and fetal distress.

Our objectives were to increase the discrimination between fetal distress and fetal well-being, using fetal heart rate spectral analysis. Monitoring of the heart rate from 259 fetuses was done between 26 and 42 weeks, interpreted with classical criteria, and analysed with the spectral analysis method we developed. The fetal heart rate spectrum analysis performed on these recordings allow discrimination of fetal distress from the normal state using the energy value and frequency of the maximal energy in the high frequency band. We can conclude that the spectral analysis produces two significant parameters which could contribute to a multivariate approach to assessments of the physiological mechanisms of heart rate variability.

Acute fetal distress after fetal blood sampling (case report).

The authors report a case of acute fetal distress after fetal blood sampling, performed for fetal karyotype because of a precocious and symmetrical fetal growth retardation without maternal hypertension or ultrasonographic evidence of fetal malformation. A cesarean section performed because of acute fetal distress showed the newborn to be hypotrophic, with a major acidosis and a refractory hypoxemia. The new born died despite intensive care. Acute fetal anemia was assumed to be the cause of acute fetal distress. The authors emphasize the use of FHR in fetal survey after fetal blood sampling.

Fetal death: coagulation defects and management. Report of 20 cases with study of the half-life of [125I]fibrinogen.

This report concerns 20 patients with intrauterine fetal death. Blood samples for coagulation studies were obtained before, during and after delivery. No clinical defibrination or bleeding was noted. Coagulation defects were observed as follows: 2 biological defibrinations: The first case was a pregnancy of 32 wk with retention for more than 12 wk; hypofibrinogenemia was noted in all 6 samples, between 180 and 280 mg/100 ml. The second was a pregnancy of 32 wk with retention for more than 8 wk; fibrinogenemia was between 170 mg/100 ml and 140 mg/100 ml. 2 intravascular coagulations with normal fibrinogenemia, increase of fibrin degradation products and positive ethanol tests. 3 cases with slight coagulation defects that were difficult to explain. The coagulation defects appeared to be transient, and sometimes resolved themselves spontaneously. Induction of labour was made in 19 cases; quinine sulfate, used in 17 cases, was remarkably successful (1 intolerance, 1 failure). Study of the half-life of [125I]fibrinogen was made in 18 of the 20 cases. On average, it was reduced by half in comparison with the half-life of healthy men. The decrease was noted even in cases of fetal deaths without the coagulation defects detected by classical tests. The half-life of [125I]fibrinogen in 6 pregnant women before therapeutic abortion was also studied. The decrease of half-life was noted. Changes of metabolism of fibrinogen during pregnancy are discussed.

Antepartum fetal heart rate monitoring. A semi-quantitative evaluation of the 'non-stressed' fetal heart rate.

1964 recordings (from 246 patients were analysed on the basis of a semi-quantitative evaluation of base-line heart rate variability. All the tracings were obtained in the antepartum period, between the 20th wk of pregnancy and prior to the onset of labour. None of the recordings were made during labour or after induction of uterine activity so that a 'non-stressed' fetal heart rate test was obtained in every case. The percentage of flat tracing in each recording and the presence of sinusoidal patterns were compared with the neonatal outcome. When the tracings included a more than 50% flat pattern, 81.8% of the babies were distressed at birth. When a less than 50% flat recording was present only 11.4% of the neonates were distressed. Sinusoidal patterns were more frequently associated with abnormal tracings including those with more than 50% flat recordings. The presence of sinusoidal features did not significantly influence the neonatal outcome for tracings with a less than 50% anomaly: conversely sinusoidal patterns superimposed on a more than 50% flat tracing were predictive of fetal compromise and neonatal distress in 100% of the cases. These results allow to advocate the use of 'non-stressed' antepartum fetal heart rate monitoring, as a reliable test in the management of high risk pregnancies.