Organotin Chemistry
Nate F. Cardarelli in Tin as a Vital Nutrient:, 2019
The steroids are a class of structurally related natural products found in plants and animals. All steroids have a tetracyclic cyclopentanoperhydrophenanthrene hydrocarbon skeleton consisting of one five- and three six-membered saturated rings which can be variously substituted by carboxylate or hydroxyl groups on aliphatic side chains or on the central ring system itself. The steric relationships within the steroid skeleton and among the attached functional groups are very specific. For example, the attached groups can either be situated above or below the plane of the rings, and up to nine asymmetric carbon atoms are found in the steroid skeleton. The relative configurations of the linking carbon atoms determine whether the junctures between the rings will be trans or cis. A typical system composed of six asymmetric carbons will have a possible 64 stereoisomers. The sterols, from which the name of the class derives, are monovalent alcohols with a secondary hydroxyl group. The best known is cholesterol. However, other commonly occurring steroids contain combinations of hydroxyl and carboxylic acid groups, with primary as well as secondary alcohol functions.
Supercritical Fluid Extraction as a Sample Preparation Tool in Analytical Toxicology
Steven H. Y. Wong, Iraving Sunshine in Handbook of Analytical Therapeutic Drug Monitoring and Toxicology, 2017
The SF-CO2 solubilities of some individual and classes of compounds of interest to toxicologists have been determined by a number of investigators. Among these compounds are the steroids. In 1986, Wong and Johnston19 obtained the solubilities of cholesterol, stigmasterol, and ergosterol in SF-CO2 with and without co-solvents over a range of 10 to 35 MPa. The solubility curves for these compounds measured at 35°C are shown in Figure 5–1. Although these sterols are similar in structure, large differences were observed in their solubilities. For instance, cholesterol exhibited three times greater solubility in SF-CO2 than stigmasterol and 50 times greater solubility than ergosterol. These differences in sterol solubility were attributed to corresponding wide differences in vapor pressures, with the vapor pressure of cholesterol about two times greater than stigmasterol and 35 times greater than ergosterol. This example illustrates an important difference between SFE and conventional liquid-liquid extraction (LLE), namely, that interactions or physical properties that are not important in organic solvent-based extractions may assume a larger significance in solute-CO2 extractions. Another study by Lee et al.20 determined the solubilities of cholesterol, progesterone, and testosterone in SF-CO2 and mixtures of SF-CO2 and N2O between 8 and 25 MPa. This study demonstrated that these compounds were soluble in the SFs at concentrations 104 to 106 greater than predicted only by the ideal gas law.
Bioscience indications for chronic disease management and neuromedical interventions following traumatic brain injury
Mark J. Ashley, David A. Hovda in Traumatic Brain Injury, 2017
The brain and nervous system produce steroids, referred to as neurosteroids, de novo and join the gonads, adrenals, and placenta as steroidogenic.224–227 Neurons and glia are involved in neurosteroid production, and production varies with location within the brain and distance from cell bodies.228 Mediation of neurosteroids is accomplished by direct or indirect modulation of neurotransmitter receptors or through ion-gated neurotransmitter receptors. Neurosteroid stimulation of neurotransmitter receptors is manifested by behavioral change, e.g., stimulation of GABAA receptors, resulting in decreases in anxiety, sedation, and seizure activity.229–239 Neurosteroids are considered to be broad-spectrum anticonvulsants and impact depression, learning, and memory; premenstrual syndrome; and alcohol withdrawal and, consequently, may merit consideration as an endocrine contribution to clinical manifestation of ABI.240 Hormone steroids act as chemical messengers and are synthesized from cholesterol. The major classes of steroid hormones include progestogens, androgens, estrogens, and corticosteroids.
Assessment of Toxicity and Wound Healing Activity of Selaginella Bryopteris Extract
Published in Drug and Chemical Toxicology, 2023
Shravan Kumar Paswan, Pritt Verma, Sajal Srivastava, Chandana Venkateswara Rao
Wound healing or repair of tissue is a linear process that involves the proliferation of cells with the integration of blood cells, soluble mediators, the proliferation of parenchymal cells and the production of extracellular matrix (Gonzalez et al.2016). Treatment for wound healing includes glucocorticoids and non-steroidal anti-inflammatory drugs (NSAIDs) that inhibit prostaglandin synthesis (Su et al.2010). Steroids are used to reduce pain, inflammation and duration of healing. However, these conventional drug therapies caused toxicities (Rowan et al.2015). On the other hand, in spite of several advancements in modern scientific research, traditional medicines are still a major source for treating numerous diseases. The demand for herbal medicines has been increasing continuously throughout the world due to their effectiveness and lesser side effects (Yuan et al. 2016; Ekor, 2014).
Advances with glucocorticoids in the treatment of asthma: state of the art
Published in Expert Opinion on Pharmacotherapy, 2020
Josuel Ora, Luigino Calzetta, Maria Gabriella Matera, Mario Cazzola, Paola Rogliani
In moderate to severe exacerbations, 40 to 50 mg daily prednisolone [39] is recommended for adults, regardless of the route of administration. The intravenous or intramuscular routes are preferred to the oral one only in case of intestinal absorption problems or poor adherence to therapy. In a Cochrane systematic review, 18 studies with different OCS regimens for asthma exacerbation were compared either in adults or children [61]. Overall, no significant differences emerged in the main outcomes (hospitalization and side effects) between the use of prednisone or dexamethasone or between the duration of the different cycles (longer versus shorter) or dosage differences (higher versus lower regimen). However, the major confounding factor in drawing definitive conclusions was that the adverse events or hospitalizations reported were too low, not allowing a valid statistical conclusion. Nevertheless, a study comparing 7 weeks of OCS tapering versus 7 days of prednisolone tapering in children and adults reported more adverse events in the long tapering group [62]. The main side effects of steroids were acne, easy bruising, oedema, and weight gain. Even if there is no definitive evidence, it is reasonable to shorten the duration of GC exposition when possible. Differently, in patients with severe asthma, GC exposure is high and prolonged. Systemic GCs are usually administered orally in a wide range of doses, starting at 1 mg [63] and averaging between 14.3 and 26.5 mg per day according to European real-life data [64].
Comparison of the efficacy of various doses of steroids for acute facial palsy
Published in Acta Oto-Laryngologica, 2019
Kuk Jin Nam, Mun Soo Han, Yong Jun Jeong, YoonChan Rah, June Choi
The purpose of this study was to determine the efficacy of corticosteroid doses for treating acute facial palsy. Patients with acute facial palsy have low self-esteem and poor quality of life. However, few studies have investigated the effects of adequate corticosteroid dose on acute facial palsy. Therefore, the treatment regimen for Bell palsy, Ramsay Hunt syndrome, and incomplete traumatic facial palsy varies among clinicians [3,4,10–12]. Despite the various etiologies underlying Bell palsy, Ramsay Hunt syndrome, and traumatic facial palsy, these diseases can be grouped into a cluster with similar treatment options. Steroids are typically used in Bell palsy, Ramsay Hunt syndrome, and traumatic facial palsy. All these diseases are associated with inflammation and swelling of the facial nerves [4,15,16]. Inflammation causes edematous changes around the facial nerves resulting in compression of certain parts of the nerve. Thus, anti-inflammatory drugs, such as corticosteroids, can be prescribed to inhibit the inflammatory process and decrease the subsequent discomfort caused by edema of the facial nerve. Although the mechanism of action of corticosteroids and their efficacy has been established, corticosteroids are associated with some side effects. The commonly occurring side effects of steroids include gastrointestinal disturbance, peptic ulcer disease, uncontrolled blood glucose levels, high blood pressure, and mood disorders [4]. Steroids should be used carefully in children, pregnant patients, and patients with diabetes [4,17].
Related Knowledge Centers
- Animal
- Membrane Fluidity
- Organic Compound
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- Sterol
- Cell Membrane
- Bile
- Cholesterol
- Bicyclic Molecule
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