The precise orchestration of hormonal regulation at all levels of the hypothalamic-pituitary-gonadal axis is essential for normal reproductive function and fertility. The pulsatile secretion of hypothalamic gonadotropin-releasing hormone (GnRH) stimulates the synthesis and release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) by pituitary gonadotropes. GnRH acts by binding to its high affinity seven-transmembrane receptor (GnRHR) on the cell surface of anterior pituitary gonadotropes. Different signaling cascades and transcriptional mechanisms are activated, depending on the variation in GnRH pulse frequency, to stimulate the synthesis and release of FSH and LH. While changes in GnRH pulse frequency may explain some of the differential regulation of FSH and LH, other factors, such as activin, inhibin and sex steroids, also contribute to gonadotropin production. In this review, we focus on the transcriptional regulation of the gonadotropin subunit genes and the signaling pathways activated by pulsatile GnRH.
Human pesticide exposure can occur both occupationally and environmentally during manufacture and after the application of indoor and outdoor pesticides, as well as through consumption via residues in food and water. There is evidence from experimental studies that numerous pesticides, either in isolation or in combination, act as endocrine disruptors, neurodevelopmental toxicants, immunotoxicants, and carcinogens. We reviewed the international literature on this subject for the years between 1990 and 2017. The studies were considered in this review through MEDLINE and WHO resources. Out of the n = 1817 studies identified, n = 94 were reviewed because they fulfilled criteria of validity and addressed associations of interest. Epidemiological studies have provided limited evidence linking pre- and post-natal exposure to pesticides with cancers in childhood, neurological deficits, fetal death, intrauterine growth restriction, preterm birth, and congenital abnormalities (CAs). In this review, the potential association between pesticide exposure and the appearance of some human CAs (including among others musculoskeletal abnormalities; neural tube defects; urogenital and cardiovascular abnormalities) was investigated. A trend towards a positive association between environmental or occupational exposure to some pesticides and some CAs was detected, but this association remains to be substantiated. Main limitations of the review include inadequate exposure assessment and limited sample size. Adequately powered studies with precise exposure assessments such as biomonitoring, are warranted to clarify with certainty the potential association between pesticide exposure and human CAs.
Summary Background Despite reports of fungal infections in patients with inflammatory bowel disease (IBD), their clinical and microbiological characteristics remain unknown. Objectives The aim of this systematic review was to examine all available evidence regarding fungal infections in patients with IBD. Methods Systematic search of PubMed (through 27 May 2017) for studies providing data on clinical, microbiological, treatment and outcome data of fungal infections in patients with IBD. The primary study outcome was to record the most common fungal species in patients with IBD. Secondary outcomes were classified into 3 categories: (i) characteristics of fungal infections; (ii) data on IBD and (iii) treatment and outcomes of fungal infections in patients with IBD. Results Fourteen studies with data on 1524 patients were included in final analysis. The most common fungal infections in patients with IBD were caused by Candida species (903 infections); the most commonly reported site of Candida infection was the gastrointestinal tract. Available evidence shows that most fungal infections occur within 12 months of IBD treatment and within 6 months when anti-TNFa agents are used. Conclusions This systematic review thoroughly describes fungal infections in patients with IBD and provides important information for the early detection and management of these infections.
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