[Fetal development and postnatal maturation of the longus colli muscle]. / Développement foetal et maturation postnatale du muscle longus colli.

In adults, the predominant expression of a slow phenotype in the m. longus colli corresponds to its important postural function. Morphologically, there is a dispersion in fiber size predominating on the fast type 2 fibers which are significantly smaller than the slow type 1 fibers. We deemed it of interest, therefore, to analyze the metabolic differentiation of the muscle longus colli during its development. This study has been carried out on six anatomical samples, in foetuses aged between 16 and 40 weeks of pregnancy and in an 18 month-old child. The histological study combined H&E staining and immunohistochemical techniques (using antibodies specific for the slow and the fast isoforms of the myosin heavy chains). Our results indicate that the m. longus colli differentiates during the foetal period in a way which is quite comparable to that of other skeletal muscles, such as the quadriceps. In this series, a major slow predominance with a significant dispersion in fiber size was first observed in the 18 month-old child. Thus, it can be concluded that the establishment of the adult phenotype of this muscle starts during postnatal life, following the development of the mechanisms holding up the head and neck and leading to the appearance of the cervical lordosis.

[Metabolic differentiation of the human longus colli muscle]. / Différenciation métabolique du muscle longus colli chez l'Homme.

The cervical muscles have a dual postural and dynamic function, in order to ensure both the stability and the motility of the cervical spine. The functional duality together with the complexity of the cervico-cephalic system render the study of the cervical muscles difficult, and their physiology is not fully understood in humans. This study has been carried out on ten samples from the m. longus colli, taken during a surgical procedure in patients aged between 36 to 62 years. The histological study combined enzyme histochemical (ATPases) and immunohistochemical techniques (using antibodies specific for the slow and the fast isoforms of the myosin heavy chains). Our results indicate that, in all cases, the m. longus colli is composed of muscle fibers with peripheral nuclei and with a relative dispersion in size. Histochemically, the type 1 and type 2 fibers express exclusively either the slow or the fast myosin heavy chain. From a quantitative point of view, the proportion of the slow fibers varies between extreme values of 30 and 73%; in addition, the dispersion in fiber size predominates on the fast type 2 fibers which are smaller than the slow type 1 fibers. Thus, most of the muscles that we have studied have histologically a slow predominance. This predominant expression of a slow phenotype in the m. longus colli corresponds to its important postural function, in addition to its phasic role during the flexion of the cervical spine.

Increased cell surface expression of histocompatibility class II I-A(d) in c-fos transfected clones of the P388D1 murine macrophage cell line.

Numerous biological functions of the monocyte-macrophage lineage are affected by the presence of immunomodulators. Enhancement in transcription of c-fos has been shown in the murine P388D1 macrophage line treated by LPS, TPA, Ca++ ionophore or dibutyryl cAMP. In order to study the effects of an increased c-Fos protein level on macrophage functions, we previously have established stable c-fos-overexpressing clones in the P388D1 cell line. Here we report that the expression of class II MHC antigens (I-A(d) antigen) is increased in these clones, particularly after IFN-gamma treatment. No variation in the cell surface expression of IFN-gamma receptor was observed. The increase of I-A(d) cell surface expression was well correlated with the level of I-A(d) mRNA. No inducible NO synthase activity and no increase of TNF-alpha release were observed in c-fos transfected cells. A slight increase of the basal expression of the main class II MHC transcription factor CIITA which is further amplified by IFN-gamma treatment, was observed in the c-Fos overexpressing clones. This suggests that the increased I-A(d) expression in clones could result from a transactivating action of the c-Fos protein on the CIITA factor.

[From bioethics to the new technology ethics]. / De la bioéthique à l'éthique des nouvelles technologies.

Just as what we can all "technoscience" is emerging in our everyday life, a reflection should be conducted concerning the implications of the scientific and technical progress within our society from now on globalised. We will tackle successively: 1. The ambiguities and paradoxes related to the development of new technologies: in the field of bioethics: artificial reproduction, mammal cloning, genetically modified organisms. towards the ethics of new technologies: ethics of information and communication technologies and ethics of space policy; 2. Nature, foundation and characteristics of the ethical approach; the precaution principle must be completed with two other principles: the principle of experience and the principle of vigilance; 3. The modalities of a democratic management of the ethical approach: it is a matter of defining the role of the three main actors, i.e.: experts, politicians and citizens representing public opinion. It is necessary to promote the ethical approach within a democratic context, that is to ensure a dialogue between experts, policy decision-makers and public opinion on all of the applications of science and technology. It is from such a permanent and renewed dialogue that will emerge the image we give from ourselves in the present world.

[Growth of spinal muscles in the human fetus]. / Croissance des muscles spinaux chez le foetus humain.

The spinal muscles, located in the paravertebral region, derive embryologically from the medial part of the somites. It has been shown in different animals that their differentiation occurs within the somite itself following the action of diffusible factors of chordal, neural and epiblastic origin. In these animal species, it thus appears that several factors determine the potential of migration as well as the muscular specification of the somitic cells. In 13 human foetuses, aged from 12 to 40 weeks of pregnancy, without any neuro-muscular disorder, transversal sections of both the vertebral and the paravertebral regions have been made at the level of the thorax and of the abdomen. Following rapid fixation, decalcification and paraffin embedding, semi-serial histological sections of 10 microns have been stained with H&E or Masson's trichrome and examined under light microscopy. Our results confirm that the primordia of the spinal muscles are present before the end of the embryonic period proper. The main modifications observed during foetal life concern the overall growth of the muscular mass, with a neat preeminence of the lombar region after 18 weeks. The differentiation of the individual muscle fibers is similar to that observed in other territories in the developing organism, with a craniocaudal gradient of maturation. Thus, if myogenic specificities really exist in the medial part of the somites in humans, it is likely that they concern the initial mechanisms involved in the activation of the myogenic program and not the mechanisms leading to the subsequent differentiation and growth of the fibres.

[Early nuclear modifications related to cellular activation: from histology to molecular cytopathology (1967-1997)]. / Modifications nucléaires précoces liées à l'activation cellulaire: de l'histologie à la cytopathologie moléculaire (1967-1997).

The nuclear chromatin structure and function are altered as soon as the first steps of cellular activation induced by membrane stimulation. Different studies carried on lymphatic tissues as well as isolated cell suspensions (lympho-monocytes) demonstrate that an early and transitory chromatin dispersion, visualised by nuclear refringency (1967), is related to the genome derepression allowing DNA transcription mechanism. This is linked to the expression of c-fos proto-oncogene and that of specific proteins synthesis. This occurs before c myc expression and could play a role in the regulation of surface antigens expression. Independent from the induction of cell proliferation, but related to cell differentiation, the early and transitory chromatin dispersion as well as the influence of c-fos related to proteic system activator (AP1) is discussed in referring to recent studies (1997), as well as the regulation factors of the chromatin filament structure.

Increased density of oligodendrocytes in childhood ataxia with diffuse central hypomyelination (CACH) syndrome: neuropathological and biochemical study of two cases.

We report neuropathological, biochemical and molecular studies on two patients with childhood ataxia with diffuse central nervous system hypomyelination (CACH) syndrome, a leukodystrophy recently defined according to clinical and radiological criteria. Both had severe cavitating orthochromatic leukodystrophy without atrophy, predominating in hemispheric white matter, whereas U-fibers, internal capsule, corpus callosum, anterior commissure and cerebellar white matter were relatively spared. The severity of white matter lesions contrasted with the rarity of myelin breakdown products and astroglial and microglial reactions. In the white matter, there was an increase in a homogeneous cell population with the morphological features of oligodendrocytes, in many instances presenting an abundant cytoplasm like myelination glia. These cells were negative for glial fibrillary acidic protein and antibodies PGM1 and MIB1. Some were positive for myelin basic protein, proteolipid protein (PLP), and myelin oligodendrocyte glycoprotein, but the majority were positive for human 2'-3' cyclic nucleotide 3' phosphodiesterase and all were positive for carbonic anhydrase II, confirming that they are oligodendrocytes. Myelin protein and lipid content were reduced. The PLP gene, analyzed in one case, was not mutated or duplicated. The increased number of oligodendrocytes without mitotic activity suggests an intrinsic oligodendroglial defect or an abnormal interaction with axons or other glial cells. This neuropathological study supports the notion that CACH syndrome constitutes a specific entity.

[Histogenesis of the corpus callosum]. / Histogenèse du corps calleux.

The corpus callosum results from neocortical commissural axon fasciculation. Its development reflects the interhemispheric circuitry and then follows the successive steps of synaptogenesis. The first stage consists of callosal neuron differentiation, which allows the extention of the future callosal axon; this is an early event that occurs while neuronal migration to the cortical plate is still ongoing. Callosal axon guidance towards its specific target is the second step which includes reaching and crossing the midline and further target recognition with formation of initial synapses. This period extends from 12 to 22 post-conceptional weeks and corresponds to the following histological features: i) progressive invasion by callosal growth cones of the dorsal part of lamina reuniens through a preformed glial pathway; ii) appearence of the three parts of corpus callosum, namely truncus, rostrum and lastly the splenium. Both these stages are genetically controlled either directly by developmental gene expression (neurogenesis genes) or indirectly by the establishment of cue maps (spatial expression of extra-cellular matrix proteins). The third step is that of synapse remodeling by synaptic activity, giving rise to axonal elimination, macroscopically revealed by a transitory thinning of corpus callosum. This perinatal event contributes to the corpus callosum acquiring a mature topography. Finally, analysis of corpus callosum ontogenesis appears as a striking model of synaptogenesis study and provides physiopathological assumptions for a understanding of the corpus callosum agenesis.

[Agenesis of the corpus callosum. Neuropathologic study and physiopathologic hypotheses]. / Agénésies du corps calleux. Etude neuropathologique et hypothèses physiopathologiques.

The neuropathological study of corpus callosum agenesis requires a two-phase approach: first it should analyze the putative causal factors, i.e. absence of callosal neurons, commissuration inability or synapse remodelling defect; secondly it has to detect any morphogenetic effects stemming from the absence of commissure such as nonregression of archicortical structures, ventricular enlargement or possible invasion of the remaining telencephaplic commissure by callosal neurons. Absence of callosal neurons due to abnormal corticogenesis gives rise to corpus callosum agenesis without callosal axon, that is without Probst's bundles. Conversely, corpus callosum agenesis occurring secondary to a commissuration default is associated with the presence of callosal axons which travel along the midline instead of crossing, that leads to the formation of Probst's bundles. This inability to cross the midline could be secondary to an obstacle, such as lipoma or as interhemispheric cysts, or primitive due to axonal guidance disturbance. In the latter situation, the commissural defect could affect the other cerebral commissures i.e. anterior or hippocampal commissures, or could become integrated into a more diffuse midline pathology involving both cerebral and extracerebral structures. Finally, it could be assumed that a synapse remodelling defect could lead to atrophy or hypertrophy of the commissure, that occurs in the absence of white matter pathology.

Effect of c-Fos overexpression on the murine macrophage cell line P388DI.

In order to study the role of Fos on the regulation of proliferation in the monocyte-macrophage lineage we realized a stable transfection of the murine P388D1 cell line by the murine c-fos gene under the control of the human metallothionein IIA promoter. Several clones have been selected by geneticin: they show a variable number of integrated transgene (two to ten copies). Their expression has been analyzed in the presence or absence of cadmium chloride as inducer (5 x 10(-6) M). In one clone especially, the c-fos mRNA and Fos protein levels were respectively 6- and 10-fold increased. The study of cell growth by tritiated thymidine incorporation indicates a negative effect of the overexpressed Fos protein in the absence of any other stimulus.

Absence of human papillomavirus DNA detected by polymerase chain reaction in French patients with esophageal carcinoma.

BACKGROUND & AIMS: Recent studies have suggested that esophageal human papillomavirus infection could be a risk factor for esophageal squamous cell carcinoma. The aim of this study was to evaluate the prevalence of human papillomavirus DNA sequences in the esophagus of French patients with esophageal squamous cell carcinoma. METHODS: Multiplex polymerase chain reactions with consensus primers directed to the L1 gene or specific primers for human papillomavirus types 6, 11, 16, 18, 31, and 33 directed to E6 gene (40 cycles followed by restriction mapping of the amplified products) were used to determine the presence of human papillomavirus DNA sequences in esophageal squamous cell carcinoma (n = 75), normal adjacent mucosa (n = 49), and metastatic lymphadenopathies (n = 5). As an internal control, a target located in the embryonic myosin heavy-chain gene was used in each reaction. RESULTS: Human papillomavirus DNA sequences could not be detected in any of the tumoral samples, the normal adjacent mucosa, or the metastatic lymphadenopathies. CONCLUSIONS: Human papillomavirus seems not to be implicated in esophageal carcinogenesis, at least in French patients, because the viral genomes are not associated with esophageal squamous cell carcinomas.

Characterization of a human perinatal myosin heavy-chain transcript.

Using a monoclonal antibody specific to the neonatal myosin heavy chain, we have cloned the full-length heavy chain cDNA from an 18-week human fetal cDNA library. Ribonuclease protection assays were used to survey a human muscle collection ranging from 11 weeks gestation to 16 years. Expression of the RNA encoded by this cDNA was observed at 20 and 21 weeks gestation and at 2 days after birth. No expression was observed at 13.5 weeks, before 2 years, at 2 years, or after 2 years gestation. Due to the timing of its expression, this cDNA appears to represent of the human fetal myosin heavy chain. Sequencing of the entire 6010 bases showed high similarity to the rat perinatal myosin heavy chain [Periasamy, M., Wieczorek, D. F. & Nadal-Ginard, B. (1984) J. Biol. Chem. 21, 13,573-13,578]. However, moderate divergence was observed when compared to a previously described human perinatal myosin heavy chain [Karsch-Mizrachi, I., Feghali, R., Shows, T. B. & Leinwand, L. A. (1990) Gene 89, 289-294; Feghali, R. & Leinwand, L. A. (1989) J. Cell Biol. 108, 1791-1797]. Restriction fragment-length polymorphism analyses of sites in both the S1 and rod domains showed the presence of this fetal myosin heavy chain sequence in all 27 genomic samples examined. Restriction fragment-length polymorphism analysis failed to find the previously described perinatal isoform in any sample.

Research on the human genome and patentability--the ethical consequences.

The genome is one of the primordial elements of the human being and is responsible for human identity and its transmission to descendants. The gene as such ought not be appropriated or owned by man. However, any sufficiently complete description of a gene should be capable of being protected as intellectual property. Furthermore, all utilisations of a gene or its elements that permit development of processes or new products should be patentable. Ethics, in the sense of moral action, should come into play from the very first stages of research into the human genome. Protection of intellectual and industrial property is of purely legal concern and need not provoke ethical consideration. By contrast, the use of the results of, and in particular the commercialisation of products deriving from, research into the human genome, ought to be subjected to ethical consideration and control. Considering the economic and societal stakes of such research, ethical analysis ought to be at an international level if mistakes and unforeseen risks of conflict are to be avoided.

Improved detection of human papillomavirus types 16 and 18 in cervical scrapes by a multiplex polymerase chain reaction: a 4% prevalence among 120 French women with normal cytology.

BACKGROUND: Cancer of the cervix is still a deadly disease. Since the finding of an association between human papillomavirus (HPV) and cervical carcinoma, the development of a reliable means of detecting viral DNA in cervical scrapes has become a priority. We have used the polymerase chain reaction to detect DNA from HPV types 16 and 18 in cervical scrapes. EXPERIMENTAL DESIGN: We designed a protocol that minimizes manipulation steps and improves control of the reaction. Our technique involves elaboration of a unique reaction mixture (core reagent) containing all reagents except Taq polymerase. Each cervical sample from controls and patients treated during the same experiment, received an aliquot of this core reagent, with the DNA polymerase added just before dispensing. The results of the amplification are visualized on a polyacrylamide gel stained with ethidium bromide. Positive results for viral DNA are confirmed by restriction mapping of the amplified products. We used HeLa cells as the positive control for HPV 18 and negative control for HPV 16 and SiHa cells for the reciprocal controls. As an internal control, we used a target in the exon 3 of the human embryonic myosin heavy chain gene. RESULTS: The polymerase chain reaction in our experiments assure a sensitivity at least equal to two copies of target per cell. We analyzed 120 cervical smears with normal cytology; only 4% gave a positive result for HPV 16. We did not detect any HPV 18 DNA. CONCLUSIONS: This prevalence, which is among the lowest reported in the literature to date, supports the concept that HPV detection may have value in aiding the prevention of cervical cancer.

De novo t(X;21)(q28;q11) in a girl with phenotypic features of Williams-Beuren syndrome.

We describe a female infant with mental retardation and some of the phenotypic features of Williams-Beuren syndrome. Chromosome analysis showed t(X;21)(q28;q11). Diagnosis, inactivation of the X chromosome, and possible involvement of the translocation breakpoints in the pathogenesis of this syndrome are discussed.

Scanning electron microscopy of femoral ossification in the human foetus.

The ossification of human femoral bone was studied in 10 fetuses aged from 8 to 40 weeks, and in a 3 1/2 month-old child. After dissection and radiographic examination, each femur was sectioned in a sagittal plane. One part was processed for routine histology, the remaining one for scanning electron microscopy. By comparing the radiographic, light microscopic and scanning electron microscopic pictures, it is possible to precise the pattern of ossification and to define 3 main periods during human fetal development (pure cartilage, metaphyseal and diaphyseal ossification, constitution of a cortex and a medulla in the diaphysis).

Segregation of three reciprocal translocations in the same family: t(3;4), t(5;10), and t(15;21).

A male infant with static antenatal encephalopathy and epilepsy was found to have a duplication of 5p12----5pter and deficiency of 10p13----10pter. Each of his parents was a carrier of a balanced reciprocal translocation. A third translocation was found in the maternal grandfather. The pedigree of each translocation and the segregation of parental reciprocal translocations are discussed.