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Biomedical subjects

A Silver

Publications and source records attributed to A Silver.

At least 73 records · Page 4Linked to original sources
PubMed1977

Acetylcholinesterase in blood vessels of the guinea-pig ovary during different phases of the reproductive cycle.

The distribution of acetylcholinesterase-containing blood vessels in the ovary has been investigated histochemically during the reproductive cycle of the guinea-pig. Whole mounts as well as frozen sections have been studied. Stained vessels were found in the stroma throughout the oestrous cycle and pregnancy. In the corpus luteum the vascular reaction varied at different stages of the oestrous cycle; while never very pronounced, it was more marked in lactating than in non-lactating animals. A feregnancy advanced an increasing number of vessels were strongly stained. At the end of pregnancy, stained vessels were less prominent. Acetylcholinesterase appeared to be localized prinicipally in the vessels themselves (possibly in muscle cells) rather than in associated nerves. Experiments in which ovaries were injected, via their arterial or venous supply, with starch or coloured gelatine suggested that most stained vessels were arterioles but a reaction also occurred in some vessels which were probably arteries and others which could have been the postulated arterio-venous shunts. Capillaries were unstained; whether the veins were also totally unreactive could not be established. The significance of the changes in acetylcholinesterase staining in varying functional states remains obscure; they may or may not reflect the emergence of certain types of vessel at different stages.

Acetylcholinesterase↗
PubMed1976

Idiopathic thrombocytopenic purpura, diabetes mellitus, and pregnancy.

A pregnancy complicated with idiopathic thrombocytopenic purpura is described. Treatment consisted of primary ceasarean section, tubal ligation, and splenectomy with good results for mother and infant. Subsequent successful pregnancies may be anticipated if the thrombocytopenia-complicated pregnancy is managed as described.

Adult↗
PubMed1974

Fall in blood pressure produced from discrete regions of the ventral surface of the medulla by glycine and lesions.

1. In cats anaesthetized with pentobarbitone sodium, atropinized by i.v. atropine methyl nitrate and artificially ventilated, experiments were carried out (a) to localize the site where glycine acts on the ventral surface of the medulla when, on topical application through paired Perspex rings caudal to the trapezoid bodies, it produces a fall in arterial blood pressure, (b) to compare the effects of uni- and bilateral application, and (c) to study the blood pressure effects produced by electrolytic lesions of the glycine-sensitive areas.2. Blood pressure fell only a little on unilateral application of glycine through one of the Perspex rings, but a pronounced fall occurred on its bilateral application. The fall was too large to be explained by two minimal responses added together. Thus the application of glycine to one side potentiated the depressor effect of glycine applied to the other side.3. By moving the paired Perspex rings rostrally or caudally to different positions on the medulla and determining for each position the effectiveness of glycine, the glycine-sensitive areas were found to be restricted to a 1.5 mm wide strip situated 1-2.5 mm caudal to the trapezoid bodies. By making electrolytic lesions within the limits of this strip the glycine-sensitive areas were found to be not wider than 1.5 mm in the mediolateral direction and to be situated about 4 mm lateral to the mid line. Histologically, such lesions involved the cells of the parvicellular part of the lateral reticular nucleus.4. Placing an electrode, with a diameter of 1 mm, under light pressure on the glycine-sensitive area produced a short-lasting steep rise in blood pressure. The same effect was produced when a current was passed through the electrode to destroy the underlying tissue, but after its destruction the passage of current no longer produced the pressor effect.5. Once the glycine-sensitive area of one side was destroyed, glycine applied to the destroyed area through one of the Perspex rings no longer produced its small depressor effect, but when applied to the intact area of the other side, a pronounced fall in blood pressure occurred. Thus unilateral destruction had the same effect as unilateral glycine application. It potentiated the depressor effect of glycine applied to the other side.6. Following unilateral destruction of the glycine-sensitive area there was only a small fall in blood pressure; following its bilateral destruction blood pressure fell to a low level.7. It is concluded that the cells in the small circumscribed glycine-sensitive areas on the ventral surface of the medulla may play a key role in the maintenance of arterial blood pressure and that the cells of one side are sufficient for this function.

Animals↗