La microvascularisation de la muqueuse vaginale et ses variations au cours du cycle ovarien chez la Femme

Résumé A la suite de recherches antérieures intéressant la vascularisation de la trompe utérine et celle de l'ovaire, la présente étude concerne la microvascularisation de la muqueuse vaginale chez la Femme et se fonde sur l'examen de dix vagins humains prélevés chez des sujets en période d'activité génitale, vagins dont le système vasculaire est injecté à l'encre de Chine gélosée.L'étude de l'angioarchitectonie de la muqueuse vaginale en général laisse apparaître un dispositif vasculaire spécifique de cette dernière et représenté au niveau du chorion par des artérioles superficielles qui s'arborisent en de multiples branches se résolvant en un réseau capillaire sous-muqueux; ce dernier est constitué d'une part, d'un dense réseau capillaire à mailles ovalaires ou polygonales, étalé sous la couche basale de l'épithélium malpighien, d'autre part, d'anses capillaires intra-papillaires, sensiblement perpendiculaires à l'épithélium malpighien et se répétant à intervalles réguliers. Ce réseau capillaire est draîné par un plexus veineux étendu que résument de volumineuses veines au calibre irrégulier.Les variations de cette angioarchitectonie au cours des diverses phases du cycle ovarien sont essentiellement marquées au cours de la 2e phase de ce cycle où elles se caractérisent par une augmentation de calibre des artérioles comme des capillaires et surtout par l'accroissement de la hauteur et de la spiralisation des anses capillaires.

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The angioarchitectony of the submucous network of the human vagina and its variations during the ovarian cycle

Summary The microvascularization of the vaginal mucosa has been investigated on 10 human vaginae taken from autopsies of women having been in their sexual active period, the vascular system of the vaginae being injected with solutions of China ink and gelose.The angioarchitectony of the vaginal mucosa shows a specific vascular pattern. The latter is represented at the level of the stroma by superficial arterioles which divide into multiple branches giving rise to the submucous capillary network. This network consists on one hand of a thick capillary plexus with ovale or polygonal stitches, spread under the basal layer of the malpighian epithelium, and on the other hand of intrapapillary capillary creeks arranged in regular intervals and perpendicularly oriented to the malpighian epithelium. This capillary network is drained by a wide spread venous plexus connected with big veins of irregular calibre.The variations of this angioarchitectony are especially pronounced during the second part of the menstrual period, when the calibre of the arterioles as well as that of the capillaries creeks grow in height and become spiralized.

     

Cloning and expression of a novel rat GABAA receptor

Two full-length cDNA clones encoding alpha- and beta-subunits of a GABAA receptor have been isolated from a rat cerebral cortex cDNA library. The mature alpha-subunit protein consists of 428 amino acids with a calculated Mr of 48,680. This protein is highly homologous (approximately 99% amino acid identity) with the bovine brain alpha 1-subunit receptor [(1988) Nature 335, 76-79]. The mature rat beta-subunit receptor is a 448 amino acid polypeptide and shares approximately 80% amino acid identity with the previously characterized bovine GABAA receptor beta-subunit [(1987) Nature 328, 221-227]. Co-expression of the cloned DNA in Xenopus oocytes produces a functional receptor and ion channel with pharmacological characteristics of a GABAA receptor. GABAA alpha- and beta-subunit mRNA is detectable in the cortex, cerebellum and hippocampus.     

Properties of condensed chromatin in barley nuclei

A method for isolation and purification of intact nuclei from barley leaves was developed and several properties of the chromatin were studied. The dense structure of the main part of the chromatin does not alter the accessibility of the DNA to nucleases. 60% of the nuclear DNA can be degraded by micrococcal endonuclease. Nevertheless the solubility of the chromatin fragments depends on the extent of nuclease digestion; solubilisation occurring only when the major part of the internucleosomal DNA was degraded (30% of digestion). Electron microscopic observations suggest that this was due to particularly dense organization of the chromatin in situ. The possible physiological meaning of some of these properties are discussed.     

Air Pollution in China: Mapping of Concentrations and Sources

China has recently made available hourly air pollution data from over 1500 sites, including airborne particulate matter (PM), SO₂, NO₂, and O₃. We apply Kriging interpolation to four months of data to derive pollution maps for eastern China. Consistent with prior findings, the greatest pollution occurs in the east, but significant levels are widespread across northern and central China and are not limited to major cities or geologic basins. Sources of pollution are widespread, but are particularly intense in a northeast corridor that extends from near Shanghai to north of Beijing. During our analysis period, 92% of the population of China experienced >120 hours of unhealthy air (US EPA standard), and 38% experienced average concentrations that were unhealthy. China’s population-weighted average exposure to PM_2.5 was 52 μg/m³. The observed air pollution is calculated to contribute to 1.6 million deaths/year in China [0.7–2.2 million deaths/year at 95% confidence], roughly 17% of all deaths in China.     

"Whey" proteins of milk of the red (Macropus rufus) and eastern grey (Macropus giganteus) kangaroo

1. A comparison is made of gel electrophoretic patterns of the "whey" proteins of the milk of red (Macropus rufus) and eastern grey (Macropus giganteus) kangaroos at various stages of lactation. Qualitative and quantitative changes occur with time during the mature phase of lactation of both types. Their onset is related solely to the stage of lactation. "Whey" proteins are isolated and characterised and the nature of protein changes determined for the first time. 2. The anodic electrophoretic pattern is divided into 6 main zones (designated A F in order of decreasing mobility) and 2 cathodic zones (G and H) that are only detected in the milk of M. giganteus. 3. Zones A, B and C are milk specific. Zone B is present throughout lactation in both species and is an alpha-lactalbumin. Zones A and C are present only in late lactation, zone C, usually, but not always, appearing first. Zone A is an alpha-lactalbumin in M. giganteus, but is not an alpha-lactalbumin in M. rufus. Zone C appears to be the same protein in both species and is possibly a beta-lactoglobulin. 4. Zone D is kangaroo serum albumin and zone E is possibly a beta 2-microglobulin. Zone F contains three main iron (III) binding bands whose relative intensity varies with stage of lactation. Their intensity differs from the corresponding blood serum transferrin bands. 5. Zone H of Macropus giganteus is a lysozyme. 6. Lactose is present in the milk, but is not the principal sugar. 7. The significance of the results is discussed.     

Expression and function of cyclooxygenase and lipoxygenase enzymes in human islets of Langerhans

Arachidonic acid (AA) is generated in pancreatic beta-cells through the activation of Ca2+-dependent cytosolic phospholipase A2 (cPLA2) and the consequent hydrolysis of membrane phospholipids in the sn-2 position of the glycerophospholipid backbone. AA acts as a second messenger in beta-cells to elevate cytosolic Ca2+ levels and stimulate insulin secretion, but it is not clear whether these are direct effects of AA or are dependent on its metabolism by cyclooxygenase (COX) and/or lipoxygenase (LOX) enzymes. In addition, much of the published data in this area have been generated using insulin-secreting cell lines or rodent islets, with very little information on AA generation and metabolism in human islets of Langerhans. This short review examines cPLA2, COX and LOX expression and function in insulin- secreting cell lines and rodent and human islets.