Search results for "Biochemistry"

Identification of Insulin in Chick Embryo Retina During Development and Its Inhibitory Effect on DNA Synthesis

1992

Incubation of chick embryo retinal explants with insulin resulted in a pronounced inhibition of thymidine uptake and incorporation into trichloroacetic acid-insoluble fraction. The inhibitory effect was highest with explants from embryos at day 7 and day 8, and thereafter it declined markedly with the age of embryos until day 11. A time-course study of the effect revealed that the inhibition occurred after a lag time; both thymidine uptake and incorporation were not altered significantly after 2-6 h of incubation with insulin, but began to decrease thereafter, reaching the maximum after 16 h. The effect was also dose dependent. After 16 h of incubation, the maximal inhibition (65%) was foun…

Induction of the adrenoleukodystrophy-related gene (ABCD2) by thyromimetics.

2009

X-linked adrenoleukodystrophy (X-ALD) is a peroxisomal disorder caused by mutations in the ABCD1 (ALD) gene. The ABCD2 gene, its closest homolog, has been shown to compensate for ABCD1 deficiency when overexpressed. We previously demonstrated that the ABCD2 promoter contains a functional thyroid hormone response element. Thyroid hormone (T3) through its receptor TRbeta can induce hepatic Abcd2 expression in rodents and transiently normalize the VLCFA level in fibroblasts of Abcd1 null mice. In a therapeutic perspective, the use of selective agonists of TRbeta should present the advantage to be devoid of side effects, at least concerning the cardiotoxicity associated to TRalpha activation. I…

In vitro free radical scavenging capacity of thyroid hormones and structural analogues.

2001

It was reported that thyroid hormones decreased Cu(2+)-induced low-density lipoprotein (LDL) oxidation in vitro. Here, we investigated free radical scavenging capacities of thyroid hormones (3,5,3'-tri-iodo-L-thyronine (T(3)), thyroxine (T(4)) and 3,3',5'-tri-iodo-L-thyronine (rT(3))) and structural analogues (L-thyronine (T(0)), 3,5,3'tri-iodothyroacetic acid (TA(3)) and 3,5,3',5'-tetra-iodothyroacetic acid (TA(4))), using three different models of free radical generation. T(0), T(3) and TA(3) slowed down production of conjugated diene and thiobarbituric acid-reactive substances during LDL oxidation by 2,2'-azobis-[2-amidinopropane] (water-soluble), whereas rT(3), T(4) and TA(4) had practi…

Menopause symptom management in women with dyslipidemias: An EMAS clinical guide.

2020

Abstract Introduction Dyslipidemias are common and increase the risk of cardiovascular disease. The menopause transition is associated with an atherogenic lipid profile, with an increase in the concentrations of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), apolipoprotein B (apoB) and potentially lipoprotein (a) [Lp(a)], and a decrease in the concentration of high-density lipoprotein cholesterol (HDL-C). Aim The aim of this clinical guide is to provide an evidence-based approach to management of menopausal symptoms and dyslipidemia in postmenopausal women. The guide evaluates the effects on the lipid profile both of menopausal hormone therapy an…

Release of non-neuronal acetylcholine from the isolated human placenta is affected by antidepressants.

2007

Non-neuronal acetylcholine (ACh) is released from the human placenta into the extracellular space via organic cation transporters (OCTs). The present experiments investigated whether ACh release from epithelial cells is affected by drugs which are substrates of OCTs. The antidepressant drugs amitriptyline and doxepine were tested as both substances are not approved for pregnant women but frequently used. Release of ACh was measured in 10 min intervals over a period of 100 min. Test substances were added from t=50 min of incubation onwards. The effect was calculated by comparing the ACh release of the last three samples (t=70-100 min; B2) with that immediately before the application of the t…

Involvement of Oxysterols and Lysophosphatidylcholine in the Oxidized LDL–Induced Impairment of Serum Albumin Synthesis by HEPG2 Cells

2000

Abstract —Oxidized low density lipoproteins (Ox-LDLs) are increasingly thought to be a key element in atherogenesis. We have previously reported that serum albumin has important antioxidant properties and that a reduced synthesis of albumin may represent a crucial point in the overall antioxidant defense. In the present work, we aimed at determining whether Ox-LDL could modulate albumin synthesis in cultured human hepatocytes (HepG2 cells). With the use of enzyme immunoassay and radiolabeled leucine incorporation followed by specific immunoprecipitation, Ox-LDL was found to lead to a dose-dependent decrease in albumin secretion. Moreover, the protein synthesis and mRNA levels were decrease…

Serum sphingomyelin levels are related to the clearance of postprandial remnant-like particles.

2005

It is known that sphingomyelin (SM) content is higher in apolipoprotein B-containing particles (BLps) than in high density lipoproteins and that BLp levels, including chylomicrons and their remnant particles, are positively related to atherosclerosis. To evaluate the relationship between serum SM and postprandial remnant particle levels, we determined SM, triglyceride (TG), and cholesterol levels in serum and in remnant-like particles (RLPs) before and 3, 5, 7, and 10 h after a high-fat meal in 31 healthy subjects. We found that serum SM, like serum TG, was increased to its maximum 3 h after fat loading and then gradually decreased to basal levels after 10 h. More important, we determined t…

Regional cerebral blood flow (rCBF) changes following local brain compression in the cat.

1968

Absorption of protein in the early postoperative period in chronic conscious dogs.

1988

Postoperative alterations in amino acid exchange across the intestinal tract and in the capacity for protein absorption were investigated in a chronic canine model. Changes in postoperative splanchnic amino acid exchange consisted of a temporary decrease of total splanchnic amino acid release, including a significant reduction in alanine production, and an increase in glutamine consumption. Contrary to results under stable metabolic conditions, branched chain amino acids were also taken up by the intestine in the early postoperative period. The changes in postoperative amino acid exchange were not, however, reflected by a corresponding alteration in protein transport capacity. The absorptiv…

Modulation by docosahexaenoic acid of the epinephrine-stimulated adenylate cyclase activity of the bovine retina.

1988

This work shows that unsaturated fatty acids enhance the epinephrine-stimulated adenylate cyclase activity in bovine retina. The modulating effect on the epinephrine-stimulated formation of cyclic AMP seems to be linked to the degree of unsaturation of the fatty acid. Treatment of the intact retina with docosahexaenoic acid in the concentration range 0.5 X 10(-6)-1 X 10(-3) M does not affect the enzyme activity measured in the absence of the hormone but markedly increases the cyclase activity when the tissue is incubated in the presence of 0.1 mM epinephrine. Docosahexaenoic acid enhances the maximal response to epinephrine without affecting the apparent ED50 value for this effector. Docosa…