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V Bernard

Publications and source records attributed to V Bernard.

At least 55 records · Page 3Linked to original sources
PubMed1992

Mechanism for the recruitment of macrophages to cancer site. In vivo concentration gradient of monocyte chemotactic activity.

BACKGROUND: Tumor stroma is characterized by the development of new blood vessels, an inflammatory cell infiltration, and a fibrotic reaction. The inflammatory component of tumor stroma plays an important role in the modulation of tumor expansion. In this respect, macrophages constitute a major part of the inflammatory cell infiltration and can exert cytotoxic activity against tumor cells. The accumulation of macrophages in the vicinity of the tumor suggests their recruitment from circulating blood monocytes through the local release of chemotactic factors for monocytes. METHODS: To detect the existence of a concentration gradient of monocyte chemotactic activity (MCA) between the tumor vicinity and blood vessels, malignant pleural effusions defined by the local presence of cancer cells were evaluated for quantification of MCA. RESULTS: Unlike nonmalignant pleural effusions, malignant pleural effusions were characterized by the presence of increased levels of MCA, and in lung adenocarcinoma (a cancer with high inflammatory cell infiltration), pleural levels of MCA were significantly greater than in small cell lung carcinoma (a cancer with low inflammatory cell reaction). An MCA concentration gradient between pleural fluid and plasma was present in malignant effusions because pleural MCA levels in all cancer types were significantly greater than MCA levels in the plasma of the same patients. CONCLUSIONS: Thus, an increased local level of MCA is a feature of cancers with high inflammatory cell infiltration, and the presence of an in vivo concentration gradient of MCA suggests the direct role of this biologic activity in recruiting blood monocytes to the cancer site.

Adenocarcinoma↗
PubMed1992

Phenotypical characterization of the rat striatal neurons expressing muscarinic receptor genes.

Neurons expressing the m1, m2, and m4 muscarinic receptor genes in the adult rat striatum were identified and characterized by using several in situ hybridization and immunohistochemical procedures. Combined in situ hybridization for the simultaneous detection of two mRNAs in the same section or in adjacent sections as well as in situ hybridization and immunohistochemistry on adjacent sections permitted us to identify the neurons containing m1, m2, or m4 receptor mRNA. Our observations demonstrate that m1, m2, and m4 receptor genes are expressed in one or several phenotypically distinct neuronal populations. The m1 receptor gene was the most widely expressed (85% of the striatal neurons). Most cholinergic neurons (80% or more) contain m1, m2, and m4 receptor mRNAs. Almost all the substance P neurons contain m1 and m4 receptor mRNA. All enkephalinergic neurons contained m1 receptor mRNA, but only 39% contained m4 receptor mRNA. Most somatostatin and neurotensin neurons expressed the m1 receptor gene, but only a few (15% and 9%, respectively) contained m4 receptor mRNA. The present study offers anatomical evidence that ACh may act directly in complex ways on the main neuronal populations of the striatum through muscarinic receptors. The m1, m2, and m4 receptors may act as autoreceptors to control ACh release and possibly other parameters of ACh neurons. On the other hand, the m1 and m4 receptors may act as heteroreceptors in cholinoceptive efferent neurons (enkephalin and substance P neurons) and other neurons (somatostatin/neuropeptide Y and neurotensin neurons). The presence of m4 receptor mRNA in only parts of the enkephalin, somatostatin, and neurotensin neuronal populations indicates that muscarinic receptor gene expression contributes to the functional and anatomical heterogeneity of the striatum that may relate to higher order of organization, including patch-matrix compartmentalization. The wide expression of m1 and m4 receptor genes in the striatum suggests that ACh may directly influence neurotransmitter release and synthesis in striatal efferent and intrinsic neurons. Our results imply that the specific pattern of expression of the muscarinic receptor genes mediates direct effects of ACh on activities and functions of chemically and topologically defined striatal neuronal populations. Since the expression of muscarinic receptors occurred in the three main neuronal populations of the striatum, namely ACh, enkephalins, and substance P neurons that also express dopamine receptors, it is highly probable that ACh and dopamine may act together at the single-cell level to influence striatal functions.

Animals↗
PubMed1991

Striatal neurons express increased level of dopamine D2 receptor mRNA in response to haloperidol treatment: a quantitative in situ hybridization study.

In the present study, quantitative in situ hybridization was used to analyse the effect of haloperidol treatment on D2 dopamine receptor gene expression in the rat caudate-putamen nucleus. Variations of D2 receptor mRNA level were studied and measured at the macroscopic level of densitometric analysis of X-ray film and at the microscopic level by counting of autoradiographic silver grains in striatal cells. Macroscopic analysis demonstrated that haloperidol treatment two times 1 mg/kg per day during seven, 14 and 21 days increased D2 receptor mRNA level in the caudate-putamen. Detailed microscopic analysis demonstrated a significant increase in D2 receptor mRNA in the two neuronal populations known to express the D2 receptor gene: medium-sized neurons previously identified as enkephalinergic neurons, and large-sized neurons previously identified as cholinergic neurons. The increase was more important in cholinergic neurons (+119%) than in enkephalinergic neurons (+54%). Haloperidol treatment did not modify the number of medium-sized enkephalinergic neurons expressing the D2 receptor mRNA. In contrast, it significantly increased the percentage of large-sized neurons containing D2 receptor mRNA (from 80 to 94%). These results demonstrate that haloperidol treatment acts at the gene level to modulate D2 receptor content in striatal dopaminoceptive neurons, and that the D2 receptor mRNA increase in postsynaptic neurons contributes to dopamine supersensitivity induced by neuroleptics in the rat. This suggests that dopamine acts trans-synaptically to control D2 receptor gene expression in target striatal neurons. These results suggest that modifications of D2 receptor gene expression may be part of the biological events that lead to the movement disorders induced by neuroleptic drugs or Parkinson's disease.

Animals↗
PubMed1988

Maitotoxin triggers the cortical reaction and phosphatidylinositol-4,5-bisphosphate breakdown in amphibian oocytes.

Maitotoxin, a potent marine toxin extracted from peredinians, was found to mimic fertilization in Xenopus oocytes and to trigger the breakdown of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2, the precursor of inositol 1,4,5-trisphosphate], an increase of intracellular pCa and the cortical reaction, including the exocytosis of cortical granules and a wave-like propagation of contraction in the animal hemisphere. All these effects of maitotoxin required the presence of external calcium. Moreover, the toxin considerably increased Ca2+ influx in amphibian oocytes arrested at first meiotic prophase, due to the permanent activation of voltage-dependent Ca2+ channels. Nevertheless it is doubtful that maitotoxin acts primarily as a Ca2+ ionophore or at the level of Ca2+ channels. Indeed no stimulation of Ca2+ uptake was observed in metaphase-II-arrested oocytes, although maitotoxin readily triggered the breakdown of PtdIns(4,5)P2 as well as the cortical reaction in such cells. On the other hand, PtdIns(4,5)P2 breakdown was not reduced in oocytes microinjected with EGTA, although the calcium chelator prevented the oocytes from undergoing the cortical reaction. Taken together, these findings support the view that the toxin might act primarily by increasing PtdIns(4,5)P2 phosphodiesterase activity.

Animals↗
PubMed1988

[Heterotopic twin pregnancies. Review of the literature after a case where the 2 children survived].

A combination of an extra-uterine and an intra-uterine pregnancy is defined as heterotopic twin pregnancy. A case is reported where the 2 infants were born alive and have had a normal psychomotor development at 3 years of age. It is a case where the first observation taken by ultrasound made the diagnosis possible at 27 weeks of the pregnancy and therefore gave rise to the crucial problem of how to manage the case. Because of this case history we have discussed the frequency (one in every 30,000 pregnancies), the aetiological factors, the clinical factors, the prognostic factors and what is to be done. The discussion takes note of the modern ways of diagnosing it (ultrasound), of monitoring it and of handling in a specialised unit this exceptional kind of "high risk" pregnancy.

Adult↗