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Biomedical subjects

C Sureau

Publications and source records attributed to C Sureau.

At least 19 recordsLinked to original sources
PubMed1995

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.

Female↗
PubMed1995

Medical deresponsibilization.

The medical profession is facing a serious challenge. The increase of technology, risks, and costs of modern medicine leads to the intervention of third parties within the medical decision-making process. This is particularly true in reproductive medicine, where a large part of medical activities are not curative, not linked with actual abnormalities, but preventive, and frequently oriented more to desire and convenience than to needs. These third parties belong to the fields of economics, administration, law, public opinion, mediatic power. This trend is universal, with some specific characteristics varying by country. The increased risk of litigation leads to an increase of all aspects of defensive medicine, with obvious medical, practical, economic deleterious consequences.

Delivery of Health Care↗
PubMed1995

Lack of detection of negative-strand hepatitis C virus RNA in peripheral blood mononuclear cells and other extrahepatic tissues by the highly strand-specific rTth reverse transcriptase PCR.

To further explore the controversial potential for extrahepatic replication of hepatitis C virus (HCV), the highly strand-specific rTth method of reverse transcriptase PCR was used to examine sera, liver, peripheral blood mononuclear cells, and other extrahepatic tissues from HCV-infected chimpanzees and humans. Positive-strand HCV RNA was present in the liver at approximately 10-fold-higher levels than negative-strand HCV RNA. No negative-strand RNA was detected in peripheral blood mononuclear cells or other extrahepatic tissues despite the presence of abundant positive-strand RNA. These data demonstrate that within the limits of sensitivity of this highly strand-specific reverse transcriptase PCR method, no extrahepatic replication of HCV was detected.

Animals↗
PubMed1994

Demonstration of in vitro infection of chimpanzee hepatocytes with hepatitis C virus using strand-specific RT/PCR.

Analysis of hepatitis C virus (HCV) replication has been hampered due to the difficulty encountered in in vitro cultivation of the virus in conventional tissue culture systems. In this study, primary chimpanzee hepatocyte cultures maintained in a serum-free medium formulation were susceptible to in vitro infection with HCV. In order to document infection, two new methods of reverse transcription/polymerase chain reaction were developed that permit accurate distinction between positive and negative strand HCV RNA. One method relied upon the use of a tagged cDNA primer, while the second method employed a thermostable reverse transcriptase. Following inoculation of chimpanzee hepatocytes with HCV, intracellular positive and negative strand HCV RNA were detectable 4 days postinfection and throughout the remainder of the experimental period, 25 days. Analysis of HCV-inoculated baboon hepatocytes revealed a total absence of negative strand HCV RNA, while residual positive strand RNA from the inoculum could be detected for up to 11 days. The in vitro replication of HCV RNA in chimpanzee hepatocytes could be suppressed by alpha-interferon. This system should be amenable to the study of HCV replication, antiviral compounds, and the development of neutralization assays.

Animals↗
PubMed1994

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.

Female↗
PubMed1994

The middle hepatitis B virus envelope protein is not necessary for infectivity of hepatitis delta virus.

The hepatitis delta virus (HDV) envelope contains the large (L), middle (M), and small (S) surface proteins encoded by coinfecting hepatitis B virus. Although HDV-like particles can be assembled with only the S protein in the envelope, the L protein is essential for infectivity in vitro (C. Sureau, B. Guerra, and R. Lanford, J. Virol. 67:366-372, 1993). Here, we demonstrate that the M protein, previously described as carrying a site for binding to polymerized human albumin, is not necessary for infectivity. HDV-like particles coated with the S plus L or the S plus M plus L proteins are infectious in primary cultures of chimpanzee hepatocytes. We conclude that the S and L proteins serve two essential functions in the HDV replication cycle; the S protein ensures the export of the HDV genome from an infected cell by forming a particle, and the L protein ensures its import into a human hepatocyte.

Animals↗
PubMed1994

[Morals, logic and ethics in reproductive medicine].

Human reproduction has always been a matter of philosophical interrogations and controversies. This situation has been reinforced by the technical evolution which has occurred during the past years. Both hopes and concerns have been raised at the same time. Two recent advancements deserve consideration and are given as demonstrative examples: intracytoplasmic injection of spermatozoon, preimplantatory diagnosis. Their consequences are very important for both the medical and the philosophical approach. One of the questions which arises at this occasion is to determine if research on pre embryos is legitimate or not. This evolution has provoked some reluctancy and several criticisms concerning the future of the children obtained by such techniques: the risk of slippery slope, possibly leading to a form of eugenics, and the fundamental and philosophical problem of the status of the embryo. However, behind these discussions a deeper and heavier controversial matter may be discovered; it deals with the role and the responsibilities of the governmental power. An opposition does exist between two different perceptions: on the one hand, the concept of a powerful governmental body, responsible for the respect of a statutory law, grounded on a sort of universal ethical rule, to be followed by all, a concept which bears the risk of totalitarianism; on the other hand, the concept of a law with a limited responsibility to protect public order, allowing a normal social life. Amongst the numerous responsibilities of the governmental power, one is often neglected, everywhere; its concerns the protection of the female life and health. Some examples are given. However the most frightening risk, much more dangerous than the frequently alleged risk of biological eugenics, is what can be called "economical eugenics". Again some examples are given, in all the systems of social protection. Submitted to ethical rules imposed by political and legal powers, and to the influence of economical forces, what will be the role and the responsibilities of the practitioner? Unfortunately the answer may be obvious: the only way is leading to a relinquishment of medical responsibility. Far away from the dialogue which was the rule of the "dual relationship" between the patient and the practitioner, away too from the more complicated situation of today, characterized by the intervention of "third parties", the evolution, probably unavoidable, appears to be towards the withdrawal of the psychological, moral, human and humanistic involvement of the practitioner, leading him or her to a technical role.(ABSTRACT TRUNCATED AT 400 WORDS)

Ethics, Medical↗
PubMed1993

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.

Animals↗
PubMed1993

Role of the large hepatitis B virus envelope protein in infectivity of the hepatitis delta virion.

The hepatitis delta virus (HDV) is coated with large (L), middle (M), and small (S) envelope proteins encoded by coinfecting hepatitis B virus (HBV). To study the role of the HBV envelope proteins in the assembly and infectivity of HDV, we produced three types of recombinant particles in Huh7 cells by transfection with HBV DNA and HDV cDNA: (i) particles with an envelope containing the S HBV envelope protein only, (ii) particles with an envelope containing S and M proteins, and (iii) particles with an envelope containing S, M, and L proteins. Although the resulting S-, SM-, and SML-HDV particles contained both hepatitis delta antigen and HDV RNA, only particles coated with all three envelope proteins (SML) showed evidence of infectivity in an in vitro culture system susceptible to HDV infection. We concluded that the L HBV envelope protein, and more specifically the pre-S1 domain, is important for infectivity of HDV particles and that the M protein, which has been reported to bear a site for binding to polymerized albumin in the pre-S2 domain, is not sufficient for infectivity. Our data also show that the helper HBV is not required for initiation of HDV infection. The mechanism by which the L protein may affect HDV infectivity is discussed herein.

Animals↗
PubMed1993

[What are the medical limits on the desire for pregnancy in the woman at risk?].

Quite a few medical situations are as difficult as the ones where the desire of procreation and the risks associated to it are in conflict. The practitioner's opinion is grounded on his experience, on statistical data, but also on his own sensitivity and subjectivity. His role is not to give the patient the medical data and to leave her deciding alone. He must involve himself in the process of reflexion and decision, recognize and appreciate the depth of the motivations and finally respect them. He must remember that the female intuition bears sometimes more value than the so called scientific knowledge.

Clinical Competence↗
PubMed1992

Production of infectious hepatitis delta virus in vitro and neutralization with antibodies directed against hepatitis B virus pre-S antigens.

Hepatitis delta virus (HDV) particles were produced in Huh7 human hepatoma cells by transfection with cloned hepatitis B virus (HBV) DNA and HDV cDNA. The particles were characterized by their buoyant density, the presence of encapsidated viral RNA, and their ability to infect primary cultures of chimpanzee hepatocytes. Successful infection was evidenced by the appearance of increasing amounts of intracellular HDV RNA after exposure to particles. Infection was prevented when particles were incubated with antibodies directed against synthetic peptides specific for epitopes of the pre-S1 or pre-S2 domains of the HBV envelope proteins before exposure to hepatocytes. These data demonstrate that HDV particles produced in vitro are infectious and indicate (i) that infectious particles are coated with HBV envelope proteins that contain the pre-S1 and pre-S2 regions, (ii) that epitopes of the pre-S1 and pre-S2 domains of HBV envelope proteins are exposed at the surface of HDV particles, and (iii) that antibodies directed against those epitopes have neutralizing activity against HDV.

Animals↗
PubMed1991

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.

Abruptio Placentae↗
PubMed1991

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.

Adult↗