SiO2 nanoparticles modulate the electrical activity of neuroendocrine cells without exerting genomic effects.

Engineered silica nanoparticles (NPs) have attracted increasing interest in several applications, and particularly in the field of nanomedicine, thanks to the high biocompatibility of this material. For their optimal and controlled use, the understanding of the mechanisms elicited by their interaction with the biological target is a prerequisite, especially when dealing with cells particularly vulnerable to environmental stimuli like neurons. Here we have combined different electrophysiological approaches (both at the single cell and at the population level) with a genomic screening in order to analyze, in GT1-7 neuroendocrine cells, the impact of SiO2 NPs (50 ± 3 nm in diameter) on electrical activity and gene expression, providing a detailed analysis of the impact of a nanoparticle on neuronal excitability. We find that 20 µg mL-1 NPs induce depolarization of the membrane potential, with a modulation of the firing of action potentials. Recordings of electrical activity with multielectrode arrays provide further evidence that the NPs evoke a temporary increase in firing frequency, without affecting the functional behavior on a time scale of hours. Finally, NPs incubation up to 24 hours does not induce any change in gene expression.

Essential oil composition and antibacterial activity of the different parts of Thymus maroccanus Ball: an endemic species in Morocco.

Three essential oils from three samples: stems, leaves and inflorescences of Thymus maroccanus Ball, obtained by hydrodistillation, were analysed by gas chromatography and gas chromatography coupled to mass spectrometry. The oils of stems, leaves and inflorescences afforded 68, 49 and 51 constituents, respectively. Quantitative and qualitative differences have been found between the analysed parts. The most abundant components in the stems oil included carvacrol (60.8%), α-terpineol (4.7%) and p-cymene (2.4%), while carvacrol (33%), p-cymene (25.3%) and α-pinene (11.6%) were the main components in the leaves. In the inflorescences, carvacrol (84.9%) is the major component. Antibacterial activity of the T. maroccanus Ball leaves oil was tested against eight Gram-positive and Gram-negative bacteria by the disc diffusion method. The values of inhibition zones for bacterial strains, which were sensitive to the essential oil of T. maroccanus leaves, were in the range of 11-43 mm.

[Primary exotropia: importance of cerebral MRI]. / Intérêt de l'IRM cérébrale dans les exotropies précoces.

INTRODUCTION: Primary exotropia is a divergent strabismus that appears from the first day of life to the second year. It can be isolated or associated with a pathological context requiring cerebral imaging to determine diagnosis and prognosis. The objective of this study was to report the sensorimotor state and the result of MRI in infantile exotropia. PATIENTS AND METHOD: Forty-seven children with primary exotropia had a complete ophthalmologic assessment (visual acuity, binocular vision, refraction with cycloplegia, eye fundus) and cerebral MRI (average age, 16 months). Deviation was classified into four categories<4 degrees, > or =4<10 degrees, > or =10<20 degrees, > or =20 degrees. MRI results were classified into seven categories: white matter abnormalities (gliosis, delay of maturation, periventricular leukomalacia, aspecific hyperintense signal, and necroses); Virchow-Robin enlargement space and enlarged subarachnoid space; gray matter abnormalities (necroses, cerebral atrophy, occipital cortex, basal ganglia); ventriculomegaly; thin corpus callosum; cerebellar injury; and tumor. RESULTS: There was a statistically significant increase in the rate of pathological MRI as the angle deviation increased: 76.6% of patients had a pathological ophthalmologic exam (amblyopia, ptosis, head posture, Duane's syndrome, cataract, albinism, or pigmentary retinopathy). We found 38% nystagmus and 38% optic nerve hypoplasia. There was a real pathological context in 61.7% of the exotropia cases: 27.7% prematurity, 31.9% fetal distress, 21.3% facial dysmorphy (plagiocephaly), 12.8% psychomotor delay, and 14.9% epilepsy. Only three children had isolated exotropia. Thirty-four cerebral MRI (72.3%) were not normal. In pathological MRI, there was 61.8% white matter injury, 41.2% gray matter injury, and 17.6% thin corpus callosum. CONCLUSION: This study demonstrates the fundamental contribution of cerebral MRI in infantile exotropia. The greater the deviation, the more abnormal the MRI results are. The pathological context and ophthalmological abnormalities are important in infantile exotropia.

Intracellular calcium signals and control of cell proliferation: how many mechanisms?

The progression through the cell cycle in non-transformed cells is under the strict control of extracellular signals called mitogens, that act by eliciting complex cascades of intracellular messengers. Among them, increases in cytosolic free calcium concentration have been long realized to play a crucial role; however, the mechanisms coupling membrane receptor activation to calcium signals are still only partially understood, as are the pathways of calcium entry in the cytosol. This article centers on the role of calcium influx from the extracellular medium in the control of proliferative processes, and reviews the current understanding of the pathways responsible for this influx and of the second messengers involved in their activation.

Shortening the VSP-A: preliminary development of the VSP-A12, a 12-item short-form.

The 'Vécu et Santé Perçue des Adolescents' (VSP-A) questionnaire is a French generic self-administered health-related quality of life (HRQL) instrument for adolescents which comprises 40 items, allowing the calculation of six dimensions as well as an index. Regression methods were used to select 12 items from the VSP-A to reproduce its HRQL index. The resulting 12-item short-form (VSP-A12) achieved an adjusted R2 of 0.907 in prediction of the VSP-A index. Scoring algorithm used to score this 12-item index achieved a R2 of 0.901 with the VSP-A index when cross-validated in the validation sample (n = 2941). Numerous tests of empirical validity previously published for the VSP-A were replicated for the VSP-A12, including comparisons between groups known to differ in terms of gender, age or health status. All the significant results shown by the VSP-A index were also encountered by the VSP-A12 summary measure. The ability of VSP-A12 to discriminate between healthy and ill adolescents was also proven. A test-retest correlation (4 weeks) of 0.745 was observed for the 12-item HRQL index in the target population (n = 664). Average score for this shorter index closely mirrored VSP-A index, although standard deviation was always greater for the VSP-A12.

[Patentability of living material: public health concerns (1/2)]. / Brevetabilité du vivant, la santé publique concernée (1/2).

A TOPICAL SUBJECT: The patentability of living material provokes debate in the scientific and medical world, but also concerns the political and legal circles. REGARDING PATENTS: Laws govern intellectual property rights and patients. There are contradictory arguments advanced by those who are in favour or who are opposed to patents, and particular problems related to the patenting of living organisms, particularly since the progress made in genomic research. ESSENTIAL PUBLIC HEALTH REQUIREMENTS: It is important to underline the limits imposed by the protection of intellectual property, regarding the access by all to any progress issued from research. The provisions must be widened in order to bypass the patents, when the health and nutrition of populations are at stake. It is essential to come to the universal accessibility, particularly in developing countries, to all innovations and that all knowledge be shared.

[Mandatory disclosure and infectious disease. From "pestilential" disease to "emerging" diseases]. / Déclaration obligatoire des maladies infectieuses. Des maladies "pestilentielles" aux maladies "émergentes".

Due to the recent overhaul of the procedure on mandatory disclosure of infectious diseases (law relating to the reinforcement of sanitation quality control established in July 1998, and the May 1999 and May 2001 decrees on the application of this law), wishing to take advantage of this opportunity, the authors propose a chronological review retracing the history of these legal declarations. For over a century, they have represented the main instrument used for intervention and surveillance allowing for the fight against infectious diseases. The health options kept have varied over the years, as well as the precautions taken to respect secrecy (nominative or anonymous disclosure, modalities of transmission...). Procedures adopted to reconcile the principle of confidentiality along with the necessity to protect public health in the case where it would require an immediate and urgent intervention are examined throughout the chronology (determining the source of contamination, prevention of contagion).

[The use of exit questionnaires, a survey at 7 hospital centers]. / L'utilisation des questionnaires de sortie, une enquête auprès de 7 centres hospitaliers.

Measuring the satisfaction of hospitalised patients has been mandatory in France since 1996. The most common tool for assessing the level of satisfaction is the use of self-administered questionnaires given to the patient upon his/her release from the hospital. A survey was conducted among seven public hospitals to appraise the development and use of such questionnaires, their results and the way in which these results are taken into account in order to improve the quality of care. The survey's results illustrate that the policy with respect to their construction varies between hospitals, without any evaluation of the validity of the questionnaires produced. In most cases, the questionnaires are passively distributed to the patient at the time of discharge. The response rates are low (ranging from 4 to 18%), and the analysis of the collected questionnaires, to the extent to which it is done, is not necessarily used to improve the quality of care. An appropriate evaluation strategy, one capable of effecting change and improving hospital care, still remains to be established in the hospitals which participated in the survey.

[Mandatory notification of HIV infection. Epidemiologic justifications and ethical questioning]. / Déclaration obligatoire de l'infection par le VIH. Justifications épidémiologiques et interrogations éthiques.

Since the appearance in May 1999 of the two decrees on the application of the law relative to the reinforcement of sanitation quality control established in July 1998, the disclosure of HIV infection "irregardless of the stage" has become mandatory. This is the first time that it is imposed that one must declare a serologic diagnosis, that is to say an infection in the asymptomatic stage. The sensitive nature of all of the information available on AIDS provides an explanation for the numerous contradictory reactions linked to this decision. We attempt to organise the arguments brought forth according to two approaches: 1) the epidemiological arguments that justify the compilation of the precise data thought to be necessary for the follow-up of the disease and for the implementation of well-targeted prevention actions; and 2) the ethical reservations concerning such an imposed measurement, as well as the questions related to anonymity and confidentiality.

Health-related quality of life reported by French adolescents: a predictive approach of health status?

PURPOSE: To examine the relevance of a self-administered multidimensional instrument to the discrimination of illness and health among adolescents in South-eastern France. METHODS: We show the results of a self-reported HRQL assessment by the Vécu et Santé Perçue de l'Adolescent (VSP-A) multidimensional questionnaire, conducted on a population of 3061 adolescents. The VSP-A produces a score for each of the seven dimensions (relationships with friends, relationships with parents, school life, inaction, psychological distress, future, and energy/vitality) and a global score. The result is compared with the answers of the parents to the same multidimensional HRQL questionnaire reworded for them (VSP-P) and to the perceived health self-reported by the adolescents on a visual analogue scale (VAS). The adolescents filled both the VSP-A and VAS questionnaires twice at a 1-month interval. RESULTS: A total of 2941 adolescents completed the questionnaire correctly, and 1760 VSP-P questionnaires were filled out by their parents. The global HRQL score as well as the dimension scores from the parents' assessment were significantly different from those of the adolescents. At the inception, using three approaches (self-reported VAS, VSP-A, and VSP-P), it was possible to discriminate between ill and healthy adolescents. Nevertheless, the VSP-A completed at the inception is the only of the three approaches that can point out the adolescents who will become ill during the following month. Furthermore, the results reported by VSP-A largely agree with literature. CONCLUSION: The VSP-A could provide a comprehensive approach of HRQL of young people in both health prevention and the health care system.

Validation of a French health-related quality of life instrument for adolescents: the VSP-A.

The French Health Ministry, stating the limits of traditional indicators to take into account the different aspects of adolescent health, declared adolescent health status assessment as a priority. Thus a French health-related quality of life (HRQL) generic self-administered indicator was developed on the adolescent's viewpoint for healthy and ill adolescents of 11-17: the VSP-A, Vécu et Santé Perçue de l'Adolescent, intended to be used as a discriminative, predictive and evaluative instrument. This paper reports the validation study of the 40-item VSP-A including 2941 adolescents. Six dimension scores were computed: psychological well-being, energy, friends, parents, leisure, school, as well as an index. Content and construct validity were confirmed. Factorial validity was shown. As expected, scale scores were significantly associated with a one-item global well-being visual analogue scale (r = 0.53; p < 0.001) and with a self-esteem score (r = 0.62; p < 0.001). On the VSP-A index, girls and older adolescents were found to have the lowest scores. The VSP-A is reliable in terms of internal consistency (Cronbach's alpha = 0.83) and test-retest results (r = 0.69; p < 0.001). The ability of VSP-A, filled in less than 15 min, was shown to discriminate between ill and healthy adolescents, and to predict an impairment of their health status. The next phase of the research involves testing in various populations and more specifically in populations with diverse acute and chronical health conditions, so as to refine the content of the instrument and to add much to what is known about the sensitivity to changes of the VSP-A scores in patients who are under treatment.

[Satisfaction with anesthesia: a review of the existing instruments]. / Satisfaction après prise en charge anesthésique: revue des différents outils existants.

EVALUATING PATIENT SATISFACTION: In France, patient satisfaction is a criteria for health care facility accreditation. In this context, the anesthesia community has studied tools available for assessing satisfaction with anesthesia. LIMITATIONS OF AVAILABLE INSTRUMENTS: The construction of a satisfaction assessment instrument can be divided into three phases: design, sorting items, validation. Instruments available in the currently literature (1987-1997) focus mainly on pre, per- or postoperative management but little on overall patient satisfaction. As the concept of satisfaction concerns a variety of elements, many of the available instruments use a multidimensional approach. The areas explored however vary greatly depending on the author or the study. In addition, patient experience is rarely taken into consideration when designing instruments. FOUR INSTRUMENTS: Among the available instruments we retained 4 questionnaires: Patient Satisfaction with General Anaesthesia, Peri-operative Anesthesia Experience Scale, Iowa Satisfaction with Anesthesia Scale, and Amerstadam Preoperative Anxiety and Information Scale. These last 2 scales only assess patient information and anxiety. The Peri-operative Anesthesia Experience Scale alone is available in French (Echelle de Vécu périopératoire de l'Anesthésie). Patient satisfaction is also approached with specialized instruments designed to assess specific items. The most widely used scales assess anxiety and pain. Based on these findings, it is dear that the fundamental concept of patient satisfaction must be revisited. We propose a few points for thought.

Neuronal survival and calcium influx induced by basic fibroblast growth factor in chick ciliary ganglion neurons.

Basic fibroblast growth factor (bFGF/FGF2) exhibits widespread biological activities in the nervous system. However, little is known about the cascade of intracellular events that links the activation of its tyrosine kinase receptors to these effects. Here we report that, in ciliary ganglion neurons from chick embryo, this trophic factor significantly enhanced neuronal survival. The percentage of surviving neurons was reduced when intracellular calcium was chelated by adding a membrane-permeable BAPTA ester to the culture medium, while antagonists of L- and N-type voltage-dependent calcium channels were ineffective. The ionic signals in response to bFGF stimulation have been studied using cytofluorimetric and patch-clamp techniques. In single-cell Fura-2 measurements, bFGF elicited a long lasting rise of the cytosolic calcium concentration that was dependent on [Ca2+]o. In whole-cell experiments, we observed a reversible depolarization of the membrane resting potential and an inward cationic current. Single channel experiments, performed in the cell-attached configuration, provide evidence for the activation of two families of Ca2+-permeable cationic channels. Moreover, inositol 1,4,5-trisphosphate opens channels with similar properties, suggesting that this cytosolic messenger can be responsible for the calcium influx induced by bFGF.

Arachidonic acid mediates calcium influx induced by basic fibroblast growth factor in Balb-c 3T3 fibroblasts.

Basic fibroblast growth factor (bFGF), a peptide acting as a mitogen in different cell types, is able to induce a long lasting non capacitative calcium influx from the extracellular medium in Balb-c 3T3 mouse fibroblasts. This effect is mediated by the tyrosine kinase activity of bFGF receptors and the opening of voltage independent, agonist activated calcium channels. In this paper we investigate the signal transduction steps involved in this process using single cell calcium fluorimetry and electrophysiological techniques. One of the pathways initiated by the binding of growth factors to their tyrosine kinase receptors is the activation of cytosolic phospholipase A2 (cPLA2) and the release of arachidonic acid (AA) from the plasma membrane with the subsequent production of eicosanoids. We show here that, in our preparation, this pathway is involved in the opening of the bFGF-activated calcium permeable channels, through the activation of mitogen activated protein kinase (MAPK) and cPLA2. Evidence for direct involvement of AA is given by the finding that: (i) bFGF induces AA release from Balb-c 3T3 cells; (ii) blockers of AA metabolism are not effective; and (iii) the application of either arachidonic acid or its non metabolizable analogue 5,8,11,14-eicosatetraynoic acid (ETYA) reproduces the responses described for bFGF. Finally, single channel analysis indicates that bFGF, AA and ETYA can activate the same calcium permeable channel.

Hormonal control of growth factor receptor expression.

In this report, we have discussed a series of results obtained in our laboratory that, together with data by other authors, demonstrate that the expression of the erbB-2 tyrosine kinase receptor oncogene in breast cancer cells is regulated by multiple factors and hormones, which modulate their growth and differentiation. In particular, we have shown that estrogens specifically inhibit erbB-2 expression by transcriptional repression, which is exerted through a sequence within the erbB-2 gene promoter. Estrogens control mammary cell growth directly, by inducing early gene expression, and indirectly, by increasing autocrine growth factor production or decreasing growth inhibitors. The data presented here suggest that mammary cells respond to estrogen also by modifying the receptor array on their surface, thus setting their own sensitivity to the different autocrine and paracrine factors. As a first consequence, the modulation of erbB-2 expression level by antiestrogen may represent a point to consider when selecting breast cancer patients for hormonal therapy, in those (few) cases where estrogen receptor positivity accompanies erbB-2 amplification. On the other hand, antiestrogen-induced upregulation of erbB-2 may improve tumor targeting of drugs designed to interact or interfere with erbB-2, such as humanized antibodies, immunotoxins, or engineered ligands. These possibilities should be tested in appropriate model systems in the future.

Role of mitogen-induced calcium influx in the control of the cell cycle in Balb-c 3T3 fibroblasts.

The role of mitogen-activated calcium influx from the extracellular medium in the control of cell proliferation was studied in Balb-c 3T3 fibroblasts. Stimulation of serum-deprived, quiescent cells with 10% foetal calf serum (FCS) induced a long-lasting (up to 70 min) elevation of intracellular free calcium concentration ([Ca2+]i). Both the sustained [Ca2+]i increase and the related inward current, described in a previous paper [Lovisolo D. Munaron L. Baccino FM. Bonelli G. (1992) Potassium and calcium currents activated by foetal calf serum in Balb-c 3T3 fibroblasts. Biochim. Biophys. Acta, 1104, 73-82], could be abolished either by chelation of extracellular calcium with EGTA or by SK&F 96365, an imidazole derivative that can block receptor-activated calcium channels. The effect of the abolition of these ionic signals on FCS-induced proliferation was investigated by adding either EGTA or SK&F 96365 to the culture medium during the first hours of stimulation of quiescent cells with 10% FCS. As measured after 24 h, a 22% inhibition of growth was observed when SK&F 96365 was added for the first hour, and stronger inhibitions, up to 56%, were obtained by adding the blocker for the first 2 or 4 h. Similar effects were observed with addition of 3 mM EGTA, though the inhibition was less marked for the 4 h treatment. By contrast, incubation with either substance in the next 4 h of serum stimulation did not influence cell growth, except for a slight inhibition observed when SK&F 96365 was applied from the 4th to the 8th hour. The reduction in growth resulting from the abolition of the early calcium influx was paralleled by an accumulation of cells in the G2/M phase. Both growth inhibition and G2/M accumulation were reversible, since after further 24 h in 10% FCS cells had fully recovered the exponential growth. These data indicate that the early calcium influx seen in response to mitogen stimulation develops on a timescale long enough to play a significant role in cell cycle progression, and that its block in the early G1 phase can lead to a reduction of proliferation by arresting cells in later stages of the cycle.

Oestrogen and epidermal growth factor down-regulate erbB-2 oncogene protein expression in breast cancer cells by different mechanisms.

Mitogen-induced mammary cell growth is often accompanied by decreased levels of expression of the p185erbB-2 protein. We have previously reported that oestrogen inhibits erbB-2 mRNA and protein expression in breast cancer cells, while epidermal growth factor (EGF) treatment has been shown to decrease p185erbB-2 levels in normal mouse mammary epithelial cells. In the present work, we studied the effect of oestrogen and EGF on erbB-2 expression in oestrogen-responsive breast cancer cells. We observed that both oestrogen and EGF comparably down-regulated p185erbB-2 levels, while stimulating growth of T47D and ZR75.1 cells. Oestrogens, but not EGF, concomitantly down-regulated erbB-2 mRNA. Run-on analysis showed a reduced erbB-2 transcription rate in the presence of oestrogens. Furthermore, the transcriptional activity of a 219 bp proximal fragment of the human erbB-2 promoter was repressed by oestrogens, whereas it was enhanced by EGF. EGF stimulated both tyrosine phosphorylation and autokinase activity of p185erbB-2 down-regulates p185erbB-2 at a post-translational level. Thus, two factors converging in terms of effects on cell growth, display divergent mechanisms of regulation of erbB-2 expression.

erbB-2 expression in estrogen-receptor-positive breast-tumor cells is regulated by growth-modulatory reagents.

It has previously been shown that, in the estrogen-receptor-positive breast-tumor cell lines T47D and ZR75.1, the erbB-2 protein and mRNA content are controlled negatively and positively by, respectively, estrogens and anti-estrogens. Since estrogens have a positive effect on cell proliferation, while anti-estrogens inhibit cell growth, the results suggested that there may be an inverse correlation between growth and erbB-2 expression. We have now examined this matter further. The effect of various growth-modulatory agents including estrogen (E2), progesterone (Pg), retinoic acid (RA), epidermal growth factor (EGF), insulin (Ins), prolactin (Prl), 12-O-tetradecanolyl-phorbol-13-acetate (TPA) and dibutyryl-3':5'-cyclic-AMP (cAMP) on c-erbB-2 promoter activity, RNA and protein expression have been examined. The growth stimulators E2 and EGF both reduced the level of erbB-2 protein. However, while E2 clearly repressed erbB-2 transcription, in the case of EGF, neither mRNA nor transcription were decreased. Of the agents which inhibit the growth of T47D and ZR75.1 cells--Pg, Prl, cAMP, RA and TPA--only Pg and cAMP caused an increase in the erbB-2 protein level. Pg and cAMP positively influenced c-erbB-2 promoter activity and RNA amount. TPA and RA also increased promoter activity but neither erbB-2 mRNA nor protein level was enhanced. The erbB-2 protein expression in cultures of T47D and ZR75.1 cells at different densities was also analyzed. Both the level of erbB-2 protein and c-erbB-2 promoter activity rose markedly in confluent cultures, suggesting a transcriptional mechanism of control. In conclusion, the data suggest that the effects of various agents on erbB-2 expression are complex and cannot be explained simply as reflecting the growth state of the cells.

Hormonal regulation of c-erbB-2 oncogene expression in breast cancer cells.

Expression of the c-erbB-2 (neu, HER-2) oncogene is found to be subjected to hormonal and developmental regulation in normal as well as neoplastic mammary cells. We have previously reported that estrogens inhibit c-erbB-2 expression at both the mRNA and protein level in estrogen receptor (ER)-positive, but not in ER-negative, breast cancer cell lines. Reversion of c-erbB-2 inhibition is seen with tamoxifen. The effect on c-erbB-2 expression of several other hormones and factors, which influence mammary cell growth and differentiation, has been studied. Our observations indicate that, in normal and neoplastic mammary cells, c-erbB-2 expression is inversely related to cell proliferation. While estrogens, anti-estrogens and cAMP clearly regulate c-erbB-2 mRNA levels, epidermal growth factor dramatically decreases the c-erbB-2 protein without affecting the level of c-erbB-2 mRNA. Therefore, different signals converging in terms of cell proliferation regulate c-erbB-2 expression by different molecular mechanisms.