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Biomedical subjects

P Lazar

Publications and source records attributed to P Lazar.

At least 19 recordsLinked to original sources
PubMed1991

The action of calcitonin gene-related peptide on astrocyte morphology and cyclic AMP accumulation in astrocyte cultures from neonatal rat brain.

The actions of calcitonin gene-related peptide (CGRP) were investigated on 9- to 14-day-old astrocyte cultures obtained from the cerebra of 1- to 2-day-old rats. The morphological appearance of the cells was monitored by immunofluorescent staining of glial fibrillary acidic protein (GFAP), and the concentration of adenosine 3',5'-monophosphate (cyclic AMP) was measured in the cultures using radioimmunoassay. CGRP induced a morphological change in cultured astrocytes from rat brain. Flat, polygonal cells positive for GFAP became multipolar with many processes. In addition, CGRP stimulated the accumulation of cyclic AMP by up to 30-fold, half maximal stimulation being obtained at CGRP concentrations in the range 100-300 nM. These data provide evidence for the presence of functional CGRP receptors on astrocytes and suggest a role for CGRP as an intercellular messenger controlling the state of differentiation and activation of astroglial cells.

Animals↗
PubMed1979

[Analysis of the geographical variations of twinning rate in France. An indirect approach to study spontaneous abortions (author's transl)].

The hypothesis of the existence of spatial variations of spontaneous abortion rates has two logical consequences on dizygotic twinning rates: they must be heterogeneously distributed and show a positive correlation with natality. French data available on dizygotic twinning rates from 1950 to 1974 are in agreement with both implications. Although alternative explanations are possible, these findings do reinforce the relevance of dizygotic twinning rate variations as a tool for the assessment of reproduction failures.

Abortion, Spontaneous↗
PubMed1979

[Organic micropollution of drinking water].

This work is about organic micropollution of waters sampled at the flowing in and out of three treatment stations. Micropollutants are obtained by chloroformic extraction. It is shown that the extracts have biological effects which can be measured by in vitro and in vivo assays. The treatments reduce the total amount of extractible substances but they induce modifications in their chemical composition and their biological activity. These observations allow to precise how the problem of an eventual health effect of organic micropollution could be approached.

Animals↗
PubMed1979

Spontaneous abortions in sibship of children with congenital malformation or malignant disease.

Parents of 751 children affected by cancer/leukemia, congenital heart disease, strawberry nevus or mental retardation have been investigated with respect to their reproductive history and their exposure to risk factors for spontaneous abortion. Differences between the four groups were established for the number of children in the sibship, the proportion of multigravidae and the spontaneous abortion rate among these women. The greatest differences were observed in the two groups of malformed children compared with the other two groups, being as marked in those with a severe malformation (heart defect) as in those with a benign one (strawberry nevus). Taking known risk factors for spontaneous abortion into account did not explain the observed differences. An etiological hypothesis is put forward which takes account of the high proportion of quantitative abnormalities of the karyotype associated with congenital heart disease and spontaneous abortion.

Abortion, Spontaneous↗
PubMed1979

Comparison of two successive policies of cervical cerclage for the prevention of pre-term birth.

The percentage of women receiving cervical cerclage increased from 5% to 18% between two periods at Haguenau maternity hospital, according to a new policy for the prevention of pre-term birth. A parallel reduction of premature deliveries by about a half was observed in the relevant group of women. This suggests that cerclage might be employed on another basis than is currently the case, and that a randomized trial is urgently needed to define its indications more precisely.

Cervix Uteri↗
PubMed1979

[An allometric study of the relative growth of the head and the body of the fetus and of the new born (author's transl)].

An allometric study of the relative growth of the head and the body of the fetus and of the newborn shows that there is a more rapid growth of the head in relationship to the length of the fetus before the 30th week of pregnancy and then there is a slowing down between the 30th and the 40th weeks, followed by a re-acceleration after birth for full term infants. This phenomenon is not shown in premature babies born before the 30th week of pregnancy who continue their head growth with the same speed after birth and slow down only for a short time near their theoretical term. These results led to a hypothesis being formed that cephalic growth is slowed down in the uterus because of steric (molecular) congestion, a slow-down that is slightly demonstrated in breech presentations and much later in very premature babies. This opens the way to a discussion on the final results of this phenomenon on the brain.

Body Height↗
PubMed1979

The etiology of human dizygotic twinning with special reference to spontaneous abortions.

The comparison of 622 twin and 622 singleton births allowed us to confirm the association of dizygotic twinning with maternal age, parity, and maternal weight and height, as well as the occurrence of unlike-sex twins in the mother's family. It was also shown that none of these associations, except for maternal height, can be explained by the others. Dizygotic twinning was also found to be negatively correlated with previous use of oral contraceptives and with irregularity of menstrual cycle. Finally, the relationship between spontaneous abortion in previous pregnancies and maternal exposure to medical irradiation was investigated.

Abortion, Spontaneous↗
PubMed1978

[Water hardness and cardiovascular mortality. Discussion of evidence from geographical pathology (author's transl)].

The existence of a significant negative correlation between hardness of drinking water and mortality rates from cardiovascular disease has been established by numerous authors. The intensity of this relationship varies according to the country concerned, the size of the areas studied, and the confounding factors taken into consideration. Nevertheless, the problem concerning the interpretation of the correlation has not yet been resolved. In particular the methodological problem resulting from the contiguity of the geographic units has been generally neglected. It is shown that these difficulties weaken the conviction that the relationship is a causal one.

Calcium↗
PubMed1978

Twinning rate and reproduction failures.

Spontaneous abortion of one of the zygotes is shown to explain some of the main epidemiologic features of dizygotic twinning: its decrease at higher maternal ages and its spatial and secular variations. Conversely, the dizygotic twinning rate offers a precious tool for the study of the etiology of reproduction failures.

Abortion, Spontaneous↗
PubMed1978

[Water hardness and cardiovascular mortality. A study of 947 alsatian communities (author's transl)].

In Alsace (France) drinking water is supplied from two different sources. This situation is favourable to study the effects on human health of various water characteristics, among which hardness. However it would be misleading to consider the 947 towns or villages as independent units of observation because of their geographical adjacencies. An aggregation algorithm of these units has been set up. It consists in a progressive regrouping of adjacent areas, similar "enough" from the point of view of the parameters studied, the aim of the procedure being to get final areas with contrasted values of water characteristics. This partition is then used to compute rank correlation coefficients between water parameters and various mortality rates. With this method, no significant correlation was found between water hardness and mortality, in spite of the existence of a sharp gradient of hardness.

Cardiovascular Diseases↗
PubMed1977

[Distribution of birth weights and influenza epidemics (author's transl)].

The possible consequences of influenza during pregnancy on the weight of the new born were studied. It was shown that the major 1969-70 winter influenza epidemic in Alsace was followed by a decrease in the mean birth weight registered in Haguenau's maternity hospital. This study confirms previous work on the subject and shows that birth weight can be used as a valuable tool at the epidemiologic scale.

Birth Weight↗
PubMed1976

[Effects of spontaneous abortions on the frequency of births of twins].

The frequency of spontaneous abortion of one zygote after double ovulation-fertilization makes it possible to explain some of the main features of the dizygotic twinning rate, namely the sharp decrease of this rate at higher maternal ages after its regular increase up to 35 years, and also the secular tendancy of this rate to decrease, observed in many countries. The consequences of these findings are discussed, in particular those which are related to the etiology of spontaneous abortion and mongolism, and to the frequency of multiple ovulation.

Abortion, Spontaneous↗