1. On the Anatomy of the Human Placenta

1845 ◽  
Vol 1 ◽  
pp. 407-409
Author(s):  
John Goodsir
Keyword(s):  
Human Placenta ◽  
Internal Surface ◽  
Internal Membrane

In the first section of the paper, the author described the parts which enter into the structure of the villi of the placenta. The villi are covered by a membrane with which anatomists are already familiar. Within this membrane, and attached to its internal surface, is a layer of cells, which has also been observed, and described as epithelium. The cells composing this layer, Mr Goodsir denominated the external cells of the villus. Th next structure is a membrane not hitherto described, and named by the author the internal membrane of the villus. The adhesion of this membrane to the external cells is so slight, that it is generally seen at some distance from them, even in villi which have undergone no violence.

scholarly journals III. On the structure of the human placenta, and its connexion with the uterus

1832 ◽  
Vol 122 ◽  
pp. 57-66 ◽  
Keyword(s):  
Human Placenta ◽  
Royal Society ◽  
Cellular Structure ◽  
Anterior Part ◽  
Internal Surface ◽  
Natural Structure ◽  
John Hunter ◽  
History Of ◽  
True Structure ◽  
Irregular Mass

In the year 1780 Mr. John Hunter presented a paper to the Royal Society, in which he laid claim to the discovery of the true structure of the placenta and its communication with the vessels of the uterus. The following is the history of the appearances which he observed in the dissection of a woman who had died undelivered near the full term of utero-gestation, and from which appearances his conclusions were drawn respecting the natural structure of these parts. The veins and arteries of the uterus having been injected, an incision was made through the parietes, at the anterior part where the placenta adhered to the internal surface. Between the uterus and placenta lay an irregular mass of injected matter, and from this mass regular pieces of the wax passed obliquely between it and the uterus, which broke off, leaving part attached to that mass; and on attentively examining the portions towards the uterus, they plainly appeared to be a continuation of the veins passing from it to this substance, which proved to be the placenta. Other vessels, about the size of a crow-quill, were seen passing in the same manner, although not so obliquely. These also broke on separating the placenta and uterus, leaving a small portion on the surface of the placenta; and on examination they were discovered to be continuations of the arteries of the uterus. The veins were next traced into the substance of what appeared placenta; but these soon lost the regularity of vessels, by terminating at once upon the surface of the placenta, in a very fine spongy substance, the interstices of which were filled with yellow injected matter. He then examined the arteries; and tracing them in the same manner towards the placenta, found that, having made a twisted or close spiral turn upon themselves, they were lost on its surface. On cutting into the placenta, he discovered in many places of its substance yellow injection, and in others red, and in many others these two colours mixed. The substance of the placenta, now filled with injection, had nothing of the vascular appearance nor that of extravasation, hut had a regularity in its form which showed it to be naturally of a cellular structure, fitted to be a reservoir for blood.

What catalysis needs from the electron microscopist

1988 ◽  
Vol 46 ◽  
pp. 694-695
Author(s):  
Alexis T. Bell
Keyword(s):  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Catalyst Deactivation ◽  
Surface Composition ◽  
Internal Surface ◽  
Active Phase ◽  
Atomic Scale ◽  
Metal Catalyst ◽  
Internal Surface Area ◽  
Porous Support

Heterogeneous catalysts, used in industry for the production of fuels and chemicals, are microporous solids characterized by a high internal surface area. The catalyticly active sites may occur at the surface of the bulk solid or of small crystallites deposited on a porous support. An example of the former case would be a zeolite, and of the latter, a supported metal catalyst. Since the activity and selectivity of a catalyst are known to be a function of surface composition and structure, it is highly desirable to characterize catalyst surfaces with atomic scale resolution. Where the active phase is dispersed on a support, it is also important to know the dispersion of the deposited phase, as well as its structural and compositional uniformity, the latter characteristics being particularly important in the case of multicomponent catalysts. Knowledge of the pore size and shape is also important, since these can influence the transport of reactants and products through a catalyst and the dynamics of catalyst deactivation.

The distribution and density of ciliary tufts on the siphons of Anodonta cygnea (Mollusca: Bivalvia)

1990 ◽  
Vol 48 (3) ◽  
pp. 518-519
Author(s):  
Wen-lung Wu
Keyword(s):  
Osmium Tetroxide ◽  
Internal Surface ◽  
Mechanical Stimuli ◽  
Type Ii ◽  
Sensory Receptors ◽  
Anodonta Cygnea ◽  
Type Iv ◽  
Sem Study ◽  
Inhalant Siphon ◽  
Type V

The mantle of bivalves has come entirely to enclose the laterally compressed body and the mantle margin has assumed a variety of functions, one of the pricipal ones being sensory. Ciliary tufts, which are probably sensory, have been reported from the mantle and siphons of several bivalves1∽4. Certain regions of the mantle margin are likely to be more or less, sensitive to certain stimuli than others. The inhalant siphon is likely to be particularly sensitive to both chemical and mechanical stimuli, whereas the exhalant siphon will be less sensitive to both. The distribution and density of putative sensory receptors on the in-and ex-halant siphon is compared in this paper.The excised siphons were fixed in glutaraldehyde and osmium tetroxide, the whole procedure of SEM study is recorded in Wu's thesis.Type II cilia cover the tips of tentacles, 6.13um. Type IV and type V cilia are found on the surface of tentacles. Type IV cilia are occasionally present at the tips of tentacles, 8 um long. They are the commonest type on the surface of tentacles. Type VI cilia occor in the internal surface of the inhalant siphon, but are not found on the surface of tentacles, 6.7-10um long.

The transfer of pravastatin in the human placenta in women with Antiphospholipid Syndrome

2017 ◽  
Vol 77 (04) ◽  
pp. 379-395
Author(s):  
K Mayer-Pickel ◽  
M Gruber ◽  
B Hirschmugl ◽  
U Lang ◽  
M Cervar-Zivkovic ◽  
...  
Keyword(s):  
Antiphospholipid Syndrome ◽  
Human Placenta

Inhibition of Platelet Aggregation by Human Placenta

1985 ◽  
Vol 54 (02) ◽  
pp. 431-437 ◽  
Author(s):  
M J Dembélé-Duchesne ◽  
A Laghchim Lahlou ◽  
H Thaler-Dao ◽  
A Crastes de Paulet
Keyword(s):  
Fatty Acid ◽  
Platelet Aggregation ◽  
Human Placenta ◽  
Cyclooxygenase Inhibitor ◽  
Synthetase Inhibitor ◽  
Inhibition Of Platelet Aggregation ◽  
Thromboxane Synthetase ◽  
Rabbit Platelets ◽  
High Doses ◽  
Induced Aggregation

SummaryHuman placental cytosol inhibits platelet aggregation induced by high doses of collagen. The aim of this study was to investigate whether this anti-aggregating activity was caused only by the presence of various activities already described in the placenta (an ADP-consuming enzyme, a fatty acid cyclooxygenase inhibitor, and a thromboxane synthetase inhibitor) or whether another factor was present.Heating the cytosol at 50° C for 6 min destroyed the inhibitor of collagen-induced aggregation. ADPase and the AA pathway inhibitors were not modified by this treatment. We therefore show the presence of an additional anti-aggregating factor: it is destroyed by heating at 50° C.We also tested for the presence of an inhibitor of AA release in the placental cytosol using three different methods (rabbit platelets in PRP, washed rabbit platelets, and NRK fibroblasts) but no inhibition could be evidenced.We conclude that this new anti-aggregating factor, which is probably a protein, acts neither through AA release inhibition nor AA cascade inhibition.

Internal surface finishing

2018 ◽  
Author(s):  
JIANG GUO
Keyword(s):  
Internal Surface ◽  
Surface Finishing

This entry introduces five kinds of established internal surface finishing technologies.

METABOLISM OF 17α-HYDROXYPROGESTERONE-4-14C-17α-CAPROATE BY HOMOGENATES OF RAT LIVER AND HUMAN PLACENTA

1961 ◽  
Vol 36 (4) ◽  
pp. 511-519 ◽  
Author(s):  
Margaret Wiener ◽  
Charles I. Lupa ◽  
E. Jürgen Plotz
Keyword(s):  
Rat Liver ◽  
Human Placenta ◽  
Steric Hindrance ◽  
Placental Tissue ◽  
Caproic Acid ◽  
Major Product ◽  
Side Chain ◽  
Anaerobic Conditions ◽  
Prolonged Action ◽  
Long Acting

ABSTRACT 17α-hydroxyprogesterone-4-14C-17α-caproate (HPC), a long-acting progestational agent, was incubated with homogenates of rat liver and human placenta. The rat liver was found to reduce Ring A of HPC under anaerobic conditions to form allopregnane-3β,17α-diol-20-one-17α-caproate and pregnane-3β,17α-diol-20-one-17α-caproate, the allopregnane isomer being the major product. The caproic acid ester was neither removed nor altered during the incubation. Placental tissue did not attack HPC under conditions where the 20-ketone of progesterone was reduced. It is postulated that this absence of attack on the side chain is due to steric hindrance from the caproate ester, and that this may account for the prolonged action of HPC.

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