Search results for "antagonists"
showing 10 items of 1346 documents
Peak half-width plots to study the effect of organic solvents on the peak performance of basic drugs in micellar liquid chromatography.
2009
The addition of the anionic surfactant sodium dodecyl sulphate (SDS) to hydro-organic mixtures of methanol, ethanol, propanol or acetonitrile with water yielded enhanced peak shape (i.e. increased efficiencies and symmetrical peaks) for a group of basic drugs (β-blockers) chromatographed with a Kromasil C18 column. The effect can be explained by the thin layer of surfactant associated to the hydrocarbon chain on the stationary phase in the presence of the organic solvents, which covers the free silanols on the siliceous support avoiding their interaction with the cationic basic drugs. These instead interact with the anionic head of the surfactant increasing their retention and allowing a mo…
Day/night serotonin levels in the pineal gland of male BALB/c mice with melatonin deficiency
1988
Abstract. Studies from another laboratory have shown that several strains of laboratory mice have a genetic defect for melatonin synthesis. In non-deficient species, melatonin synthesis undergoes a typical, β-adrenergically regulated day/night rhythm with low melatonin levels during daytime and high levels at night, the precursor serotonin showing an inverse behaviour. This study examines whether a day/night rhythm of pineal serotonin levels exists in melatonin-deficient male BALB/c mice. Mice kept under a lighting schedule of 12 h light (lights on at 07.00 h) and 12 h dark were killed at 13.00 and 01.00 h, respectively. Serotonin amounted to 12-15 ng/pineal and did not show regular day/nig…
The pineal complex in Roman high avoidance and Roman low avoidance rats.
1990
Previous studies have shown that the pineal gland of Roman high avoidance (RHA/Verh) rats is larger than that of Roman low avoidance rats (RLA/Verh). In the present study measurement of enzyme activities (serotonin-N-acetyl-transferase, hydroxyindole-O-methyltransferase) revealed that pineals of RHA/Verh rats are twice as active in melatonin production than pineals of RLA/Verh rats. Indoleamine content was also higher in RHA/Verh rats, whereas noradrenaline content was the same in both lines. When values were expressed per mg protein, these differences disappeared except for N-acetyl-serotonin and noradrenaline which were higher or lower in RHA/Verh rats, respectively. Both lines had higher…
Melatonin formation in different parts of the guinea-pig pineal complex as assessed over 24 hours.
1985
There is morphological evidence that the pineal gland is not a uniformly built organ but rather a complex. In the guinea-pig the gland is 6--7 mm in length and dumbbell-shaped, the proximal part coming into intimate contact with central commissural fibres. The aim of the present 24-hour study was to examine in male guinea-pigs whether the proximal, intermediate and distal areas of the gland are involved in melatonin formation and to compare their rhythmicities. Levels of melatonin in serum and the whole pineal gland as assessed by RIA show day/night ratios of 1 : 1.25 and 1 : 3.3, respectively. Serotonin N-acetyltransferase activity was found to exhibit ratios of 1 : 1.75 (Experiment I) and…
Symptom variability and control in COPD: Advantages of dual bronchodilation therapy
2017
Abstract Background Chronic obstructive pulmonary disease (COPD) is a heterogeneous disorder characterized by usually progressive development of airflow obstruction that is not fully reversible. While most patients will experience symptoms throughout the day or in the morning upon awakening, many patients do not experience their symptoms as constant but report variability in symptoms during the course of the day or over time. Symptom variability adversely affects patients' health status and increases the risk of COPD exacerbations. Methods We examined data from the literature on symptom variability and control in patients with COPD, with focus on the use of inhaled bronchodilator therapy wi…
Association of Serum Procalcitonin With Cardiovascular Prognosis in Coronary Artery Disease
2011
Background: Procalcitonin (PCT) is an established biomarker for the diagnosis of sepsis. Evidence is growing that PCT concentration correlates with the extent of atherosclerosis and prognosis in patients with coronary artery disease (CAD). Methods and Results: A total of 2,131 patients with CAD were followed up for a median of 3.6 years. During follow-up, death from cardiovascular causes was registered in 95 patients and non-fatal myocardial infarction in 85 patients. Median and quartile 1 and 3 are reported for PCT concentration. Patients who died of cardiovascular causes had higher PCT concentrations [0.021 (0.012/0.036) ng/ml vs. 0.015 (0.010/0.023) ng/ml; P<0.0001]. Patients with acute …
Fine-needle biopsy of parathyroid adenomas
1986
High-resolution real-time sonography was performed in 15 cases of clinically and chemically suspected primary hyperparathyroidism and in 20 patients with different thyroid nodules. The suspected enlarged parathyroid glands and the thyroid nodules were percutaneously punctured under sonographic control. Concentrations of parathyroid hormone, human thyroglobulin, and human calcitonin were measured in the aspirate, and immunocytology was performed. The mean concentration of the aspirated parathyroid hormone in the parathyroid glands was 4,013.6 pmol/l +/- 4,519 (SD) as compared with 14.9 pmol/l +/- 8.7 in the thyroid nodules. Thyroglobulin was present in the aspirated fluid of parathyroid aden…
An in vitro model for the study of human parathyroid gland tissue: Single cell suspensions and monolayer cultures
1982
An in vitro model for studies of parathyroid physiology is described using single cell suspensions and adherent monolayer cultures of human parathyroid tissue. The isolated cells were viable and maintained functional properties tested by calcium and magnesium sensitivity. Parathyroid hormone (PTH) secretion could be suppressed by rising calcium and magnesium concentrations. The secretory behaviour of the cells was not altered by cultivation or cryopreservation. The morphological integrity of the individual cells after mechanical and enzymatic preparation was confirmed by light and electron microscopy.
Pharmacological Interventions on Asymmetric Dimethylarginine, a Clinical Marker of Vascular Disease
2011
The aim of this paper is to review the latest data on the pharmacological modulation of asymmetric dimethylarginine in human disease. When the terminal nitrogens of the guanidine portion of an arginine become methylated through the action of N-methyl transferases, two chemically close, but physiologically different amino acids are synthesized: symmetric and asymmetric dimethylarginine. The vascular origin of asymmetric dimethylarginine and its inhibitory activity on endothelial nitric oxide synthase give it an important role in certain diseases in which microcirculation is compromised: hypertension, atherosclerosis, inflammatory bowel disease, and diabetes. This review discusses the role th…
Early management of COPD: Where are we now and where do we go from here? a delphi consensus project
2019
Fabiano Di Marco,1 Piero Balbo,2 Francesco de Blasio,3 Vittorio Cardaci,4 Nunzio Crimi,5 Giuseppe Girbino,6 Girolamo Pelaia,7 Pietro Pirina,8 Pietro Roversi,9 Pierachille Santus,10,11 Nicola Scichilone,12 Alessandro Vatrella,13 Patrizio Pasqualetti,14 Mauro Carone15 1Department of Health Sciences, University of Milan, Respiratory Unit, Papa Giovanni XXIII Hospital, Bergamo, Italy; 2SC Malattie dell&rsquo;Apparato Respiratorio, AOU Maggiore della Carit&agrave;, Novara, Italy; 3Respiratory Medicine and Pulmonary Rehabilitation Section, Clinic Center S.p.A. Private Hospital, Department of Medicine and Health Sciences &ldquo;V Tiberio&rdquo;, University of Molise, Campobasso, It…