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Biomedical subjects

S A Saeed

Publications and source records attributed to S A Saeed.

At least 91 records · Page 5Linked to original sources
PubMed1982

Inhibition of prostaglandin biosynthesis by human low-density and high-density lipoproteins.

The ability of human low-density lipoprotein (LDL) and high-density lipoprotein (HDL) to inhibit the biosynthesis of prostaglandin (PG) E2, F2 alpha prostacyclin from arachidonic acid by bull seminal vesicle (BSV) PG synthase was studied. Both LDL an HDL inhibited the PG synthase activity in BSV microsomes. The greatest inhibitory effect was observed against th biosynthesis of PGE2. These results show an higher to unrecognised property of human lipoproteins that may mediate some of the biological actions of these substances.

Adult↗
PubMed1982

Endogenous peptides that inhibit brain cyclic AMP phosphodiesterase.

Peptide extracts of rat brain powerfully inhibited the cyclic AMP phosphodiesterase activity of rat brain homogenate. Similar extracts of ox brain showed comparable although less potent activity. Preliminary investigation of the physicochemical properties of brain extracts indicated that the rat brain extract contained an active peptide of low molecular weight (about 1400), whereas ox brain contained two such peptides (about 1400 and 900). These studies indicate that endogenous oligopeptides that inhibit cyclic AMP phosphodiesterase are present in brain. Experiments on several pure peptides known to be present in brain. Experiments on several pure peptides known to be present in the CNS showed that the majority were inactive against brain phosphodiesterase, but ACTH(1-24), somatostatin, substance P and Lys8-vasopressin, in descending order of potency, were active. To help distinguish the peptides found in rat and ox brain extracts from known peptides, preliminary analyses of amino acid composition were performed. These suggested that the peptides found in brain extracts were distinct from known peptides having the ability to inhibit cyclic AMP phosphodiesterase.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1982

Inhibiton of prostaglandin synthesis by human amniotic fluid: acute reduction in inhibitory activity of amniotic fluid obtained during labor.

Human amniotic fluid contains an inhibitor of prostaglandin synthesis. The activity of the inhibitor was measured in amniotic fluid obtained in early pregnancy, and at term both before and after the onset of labor. The inhibitory activity was greater in amniotic fluid taken in early pregnancy than in fluid taken at term before the onset of labor (P less than 0.05). There was a further significant reduction in inhibitory activity (P less than 0.01) in amniotic fluid collected during labor. These results are suggestive that the onset of labor is associated with a local withdrawal of inhibition of prostaglandin biosynthesis.

Albumins↗
PubMed1982

Formation of arachidonate lipoxygenase metabolites by human fetal membranes, uterine decidua vera and placenta.

Homogenates (1000 x g supernatant fraction) of human amnion, chorion laeve, decidua vera and placenta were incubated with [1(-14)C] arachidonic acid in the presence or absence of indomethacin, an inhibitor of cyclooxygenase activity and nordihydroguairetic acid (NDGA), an inhibitor of lipoxygenase activity. After incubation, the products were extracted with ethyl acetate and identified by thin layer chromatography and high performance liquid chromatography. The major lipoxygenase products formed by human amnion, decidua vera and placenta were 12-L-hydroxy-5,8,10,14-eicosatretetraenoic acid (12-HETE) and smaller amounts of 5-HETE. Chorion laeve produced only a trace amount of 12-HETE. The formation of these products was abolished by NDGA and slightly stimulated by indomethacin. These findings demonstrate the existence of lipoxygenase activity in human intra-uterine tissues and suggest that products of lipoxygenase activity in these tissues may regulate the recruitment of leukocytes and/or macrophages during pregnancy and parturition.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1981

Prostaglandin synthesis inhibition by maternal and fetal sheep plasma and its relation to haptoglobin and albumin levels.

Mammalian plasmas and sera have been reported to contain endogenous inhibitors of prostaglandin synthesis (EIPS), but the identity and role of these suggested inhibitors is as yet undetermined. Albumin and haptoglobin have been proposed as possible inhibitors, and it has been suggested that EPIS may have a part to play in the control of PG production during pregnancy and in the neonatal period. As part of a series of studies aimed at elucidating the identity and role of EIPS, maternal and fetal blood samples were collected from chronically catheterized pregnant ewes, and plasma levels of albumin, haptoglobin and EIPS activity determined. Pregnant ewe plasma possessed high EIPS activity and fetal lamb plasma little or no EIPS activity. Levels of albumin and/or haptoglobin did not consistently parallel that of EIPS activity. A post-operative rise (4 sheep studied) and a pre-parturition nadir (1 sheep studied) in maternal plasma EIPS activity were also noted. The possible physiological significance of these results is discussed.

Animals↗
PubMed1981

Comparisons between the abilities of various human and ovine plasmas to inhibit prostaglandin synthesis.

The ability of various human and ovine blood plasmas to inhibit prostaglandin synthesis in vitro has been tested. Human plasmas were significantly more potent in their ability to inhibit prostaglandin synthesis than their counterpart ovine plasmas. In general, female plasma had greater inhibitory activities than male plasmas and adult plasmas were more active than fetal plasmas. There was no simple correlation between the activity of plasmas as inhibitors of prostaglandin synthesis and their respective albumin or haptoglobin contents.

Age Factors↗