Search results for "HORMONES"
showing 10 items of 1169 documents
In vitro evaluation of glycol chitosan based formulations as oral delivery systems for efflux pump inhibition.
2017
Recently, we have reported that glycol chitosan (GCS) was able to reverse the P- glycoprotein (P-gp) efflux pump. The objective of the present study was to evaluate the potential of two GCS-based dosage forms (aqueous solution or nanoparticle suspension) for oral administration of the P-gp substrate Rho-123. A further aim of the present study was to assess the effect of the glycol chitosan-4-thiobutylamidine thiomer (GCS-TBA) on P-gp activity considering that the corresponding thiomer of chitosan series is a well-known P-gp inhibitor. Pre-treatment of Caco-2 cell monolayer with a GCS solution or GCS-based nanoparticles increased the absorptive transport of Rho-123 across the monolayer of 1.…
Melatonin levels in Parkinson's disease: Drug therapy versus electrical stimulation of the internal globus pallidus
1997
The objective of our work was to measure plasma melatonin levels in patients with Parkinson's Disease (PD) following electrical stimulation of the internal globus pallidus (GPi), and to compare these levels with groups of PD patients under drug therapy and healthy controls. The levels of melatonin were measured twice daily at 1000 and 1200. The GPi stimulation at 130 Hz lowered melatonin levels, while no changes were observed in the absence of stimulation. The melatonin levels from healthy subjects were lower than those observed in PD patients. The melatonin levels from PD patients under drug therapy were also measured during the night (2000-2400-0400) and at 0800 in order to observe their …
Differenzierung zwischen prämaturer Thelarche und Pubertas praecox anhand klinischer, hormoneller und radiologischer Befunde
2008
In a retrospective study of 39 girls (aged 10 months to 7 10/12 years) with premature breast development criteria for distinguishing between premature thelarche and precocious puberty were analysed. Serum estradiol levels and bone age were determined and a test with luteinizing hormone-releasing hormone (LHRH) performed (inclusion criteria). On the basis of the LHRH test and bone age, premature thelarche was diagnosed in 29 patients and precocious puberty in ten: while those with premature thelarche had a follicle-stimulating hormone (FSH) pattern of rise, in those with precocious puberty the rise in gonadotropin was of the LH type. The LH/FSH ratio 30 min after stimulation was 1 (median 2.…
Origin of Insulin Receptor-Like Tyrosine Kinases in Marine Sponges
1999
One autapomorphic character restricted to all Metazoa including Porifera [sponges] is the existence of transmembrane receptor tyrosine kinases (RTKs). In this study we screened for molecules from one subfamily within the superfamily of the insulin receptors. The subfamily includes the insulin receptors (InsR), the insulin-like growth factor I receptors, and the InsR-related receptors--all found in vertebrates--as well as the InsR-homolog from Drosophila melanogaster. cDNAs encoding putative InsRs were isolated from the hexactinellid sponge Aphrocallistes vastus, the demosponge Suberites domuncula, and the calcareous sponge Sycon raphanus. Phylogenetic analyses of the catalytic domains of th…
Electrophysiology of the Mammalian Pineal Gland: Evidence for Rhythmical and Non-Rhythmical Elements and for Magnetic Influence on Electrical Activity
1982
Although the mammalian pineal gland has been extensively studied by biochemical, pharmacological and morphological techniques, the precise nature of the intrinsic cells, the pinealocytes, was unknown for a long time. Biochemically the pinealocyte has been shown to be an endocrine cell synthesizing melatonin and other hormones. In view of the importance of the mammalian pineal as a neurotransducer, and of the limited usefulness of the methods mentioned, an attempt was made to characterize the cells electro-physiologically.
A mutation in the second intracellular loop of the pituitary adenylate cyclase activating polypeptide type I receptor confers constitutive receptor a…
2000
AbstractThe pituitary adenylate cyclase activating polypeptide (PACAP) type I receptor belongs to the glucagon/secretin/vasoactive intestinal polypeptide (VIP) receptor family. We mutated and deleted an amino acid residue (E261) which is located within the second intracellular loop of the rat PACAP type I receptor and which is highly conserved among the receptor family. The wild-type receptor and the mutant receptors were efficiently expressed at the surface of COS-7 cells at nearly the same level and revealed the same high affinity for the agonist PACAP-27. The cAMP contents of COS cells transfected with the E261A, E261Q, and the deletion mutant receptor were 4.6-, 5.7-, and 6.7-fold highe…
The Effect of High Parathyroid Hormone Concentration on Calcitonin in Patients with Primary Hyperparathyroidism2)
2009
Serum calcitonin (CT), parathyroid hormone (PTH), and calcium levels were measured in 23 patients with primary hyperparathyroidism. PTH was determined by a midregion (M-RIA) and a carboxyl-terminal (C-RIA) specific PTH-RIA. Only 2 patients had elevated CT levels. In contrast to the findings in 46 healthy controls, the CT levels did not correlate with calcium levels. Patients who had the highest iPTH values showed a negative correlation between CT and iPTH (M-RIA (n = 7): R = -1.0000, p less than 0.001; C-RIA (n = 13): R = -0.5604, p less than 0.05). The results of the C-RIA were subtracted from those of the M-RIA. In 12 patients with the highest levels of intact PTH (M-RIA - C-RIA), serum P…
Germinal center B cells govern their own fate via antibody feedback
2013
High-affinity antibodies reenter germinal centers (GCs) and limit antigen access, thus causing sustained directional evolution in GCs toward higher-affinity antibody production.
Serum inhibin A, inhibin B, pro-alphaC, and activin A levels in women with idiopathic premature ovarian failure.
2003
Serum inhibin A, inhibin B, pro-alphaC, and activin A levels in 30 women with idiopathic premature ovarian failure (POF), 30 postmenopausal women, and 30 age-matched fertile women were determined. Women with POF showed low levels of inhibin A and inhibin B, but not of activin A, whereas the levels of pro-alphaC were significantly higher than in postmenopausal women. Thus, the circulating level of pro-alphaC could be a marker for assessing residual ovarian function in women with POF.
Localization and interactions of melatonin in dry cholesterol/lecithin mixed reversed micelles used as cell membrane models
2005
The state of melatonin confined in dry cholesterol/lecithin mixed reversed micelles dispersed in CCl4 was investigated using 1H-NMR and FT-IR spectroscopies as a function of the melatonin to lecithin molar ratio (R(MLT)) and of the cholesterol to lecithin molar ratio (R(CHL)). An analysis of experimental results leads to the hypothesis that, independent of R(MLT) and as a consequence of anisotropic melatonin/lecithin, melatonin/cholesterol and cholesterol/lecithin interactions, melatonin is totally solubilized in reversed micelles. Melatonin is mainly located in and oriented in the nanodomain constituted by the hydrophilic groups of cholesterol and lecithin. A competition of melatonin and c…