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DRCOG OSCE for Circuit A Answers
Published in Una F. Coales, DRCOG: Practice MCQs and OSCEs: How to Pass First Time three Complete MCQ Practice Exams (180 MCQs) Three Complete OSCE Practice Papers (60 Questions) Detailed Answers and Tips, 2020
Surgical treatment involves myomectomy. The patient should be informed of the small risk of a hysterectomy when consenting to a myomectomy. Zoladex (goserelin) is a gonadorelin analogue. It is administered as a subcutaneous 3.6-mg implant into the anterior abdominal wall every 28 days for 3 months before myomectomy to shrink the fibroid and facilitate surgery. Patients should be warned of the menopause-like symptoms associated with zoladex.
Erectile Dysfunction
Published in Philipa A Brough, Margaret Denman, Introduction to Psychosexual Medicine, 2019
The intended mode of action of some drugs will have an adverse effect on erections. Treatment for prostatic cancer aims to reduce the testosterone levels and ED is almost inevitable, partly due to loss of desire. Gonadorelin analogues will certainly reduce testosterone and anti-androgens such as cyproterone acetate, dutasteride or finasteride may cause ED.
Endocrine Therapies
Published in David E. Thurston, Ilona Pysz, Chemistry and Pharmacology of Anticancer Drugs, 2021
Gonadotropin-Releasing Hormone (GnRH), also known as Luteinizing Hormone–Releasing Factor (LH-RF), Luteinizing Hormone–Releasing Hormone (LH-RH), gonadorelin, gonadoliberin, or luliberin, is a neurohumoral trophic peptide hormone of molecular weight 1,182.29 kDa (Figure 8.23). It is considered a neurohormone as it is produced in specific neural cells in the hypothalamus and released at their neural terminals, and represents the initial step in the hypothalamic–pituitary–gonadal axis. It was first isolated from porcine hypothalamic extracts, and its structure elucidated and confirmed by synthesis in the early 1970s. The function of GnRH in the body was elucidated by Roger Guillemin and Andrew V. Schally who received the 1977 Nobel Prize in Physiology or Medicine for their work. It is now known that this hormone is the product of the GNRH1 gene located on chromosome 8 which codes for the GnRH precursor, a 92-amino acid prehormone found in the preoptic anterior hypothalamus. This is converted to the linear decapeptide end product as required. Peptides are normally drawn as a linear sequence as shown in Figure 8.23 with the amino terminus (on the left), with the assumption that all amino acids are in their L-form unless otherwise stated. Therefore, the -NH2 group at the carboxyl terminus (right-hand side as drawn in Figure 8.23) indicates that GnRH terminates as a carboxamide rather than a free carboxylate. The decapeptide also contains the nonstandard amino acid 5-oxoPro (5-oxoproline or L-pyroglutamyl) at the N-terminus. The GnRH analogues described below also contain nonstandard amino acids, along with some standard amino acids but with D-stereochemistry. Structure of the Gonadotrophin-Releasing Hormone (GnRH) decapeptide.
Current approaches to overcome the side effects of GnRH analogs in the treatment of patients with uterine fibroids
Published in Expert Opinion on Drug Safety, 2022
Mohamed Ali, Mohamed Raslan, Michał Ciebiera, Kornelia Zaręba, Ayman Al-Hendy
Gonadotropin-releasing hormone (GnRH) analogs have been one of the main pharmacological modalities in the treatment of UFs [8,32]. These analogs have been extensively used in clinical medicine since they were identified and synthesized in 1971 [33]. These drugs are used in gynecology and oncology for the modulation of the pulsatile release of GnRH. They bind to the receptor of the frontal lobe of the pituitary gland inhibiting the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH and FSH are peptide hormones that regulate ovarian and testicular function and are essential for normal growth, sexual development, and reproduction. These pituitary gonadotropins are under the control of the above mentioned GnRH, which is produced in the hypothalamus and released in response to the circulating levels of estrogens and progesterone [34]. GnRH analogs are made of different peptides and are structurally related to GnRH. Very recently researchers have also obtained new small molecules (e.g. elagolix), which are structurally distinct (non-peptide) from and unrelated to GnRH analogs [35]. The majority of the above-mentioned substances present antigonadotropic properties. However, some may present pro-gonadotropic properties (e.g. gonadorelin), depending on whether they act to increase or decrease gonadotropin release [34].
The role of peptide-based therapeutics in oncotherapy
Published in Journal of Drug Targeting, 2021
Selin Seda Timur, R. Neslihan Gürsoy
One study utilised gonadotropin releasing hormone analogs for active targeting of chemotherapeutics through receptor mediated internalisation: He et al. used gonadorelin-modified liposomes for targeted delivery of mitoxantrone to MCF-7 breast cancer cell line overexpressing LHRH receptor [46]. The use of LHRH analog for receptor targeted delivery has increased the accumulation of mitoxantrone in cell line overexpressing LHRH as compared to cell with low LHRH expression. Stephenson et al. also proposed the use of group of dendritic lipidated GnRH-1 analogs to facilitate the specific uptake by prostate cancer cells in vitro [47]. They mentioned that the growth of GnRH-positive prostate cancer cell lines was inhibited signifying this novel strategy allows cell-specific binding and internalisation of drug delivery systems via the GnRH receptor.
Effect of drug load and lipid–wax blends on drug release and stability from spray-congealed microparticles
Published in Pharmaceutical Development and Technology, 2022
Hongyi Ouyang, Soon Jun Ang, Zong Yang Lee, Tze Ning Hiew, Paul Wan Sia Heng, Lai Wah Chan
Various studies have shown that spray-congealed microparticles can be adapted to achieve different drug delivery outcomes by varying the process and formulation parameters. As spray-congealed microparticles comprise a drug that is entrapped within or surrounded by the matrix material, they can be used to modify drug release (Bodmer et al. 1992; Novartis et al. 1996; Rodriguez et al. 1999; Passerini et al. 2002; Quadir et al. 2003; Savolainen et al. 2003; Park et al. 2004; Bilati et al. 2005; Jaspart et al. 2005) and mask the taste of unpleasant drugs (Yajima et al. 1996, 1999, 2002, 2003; Qi et al. 2006; Uchida et al. 2010). Several factors can be varied to obtain the desired drug release profiles, for instance, the physical properties of the drug (Savolainen et al. 2002), size of microparticles, type of matrix materials (Akiyama et al. 1993) and additives. With regard to the matrix materials, hydrophilic carriers such as polyethylene glycols (Fini et al. 2002; Oh et al. 2015, 2016), poloxamers (Kulthe and Chaudhari 2014) and gelucires (Cavallari et al. 2005, 2014; Bertoni, Albertini, Ferraro, et al. 2019; Bertoni, Albertini, et al. 2020) have been used to improve the drug release of poorly water-soluble drugs. In contrast, lipophilic carriers such as carnauba wax (Emås and Nyqvist 2000), microcrystalline wax (Passerini et al. 2003), hydrogenated vegetable oils (Hassan et al. 1995; Guo et al. 2005; Consoli et al. 2016), tristearin (Scalia et al. 2013) and glyceryl behenate (McCarron et al. 2008) have been employed for sustained drug release. In addition, peptides such as glutathione (Bertoni, Albertini, Facchini, et al. 2019) and gonadorelin (Traub-Hoffmann et al. 2020) as well as the catalase protein (Bertoni, Tedesco, et al. 2020) have also been encapsulated successfully without modification or degradation during the spray congealing process.