Biochemical characterisation and immunohistochemical localisation of the secretogranin II-derived peptide EM66 in the hypothalamus of the jerboa (Jaculus orientalis): modulation by food deprivation

The neuroendocrine protein secretogranin II is the precursor of several neuropeptides, including secretoneurin and a novel 66-amino acid peptide, EM66, the sequence of which has been highly conserved across the vertebrae phylum. The presence of EM66 has been detected in the adult and fetal human adrenal gland, as well as the rat pituitary and adrenal glands. The present study aimed to explore a possible neuroendocrine role of EM66 by analysing its occurrence and distribution within the jerboa hypothalamus, and its potential implication in the control of feeding behaviour. High-performance liquid chromatography analysis of jerboa hypothalamic extracts combined with a radioimmunoassay of EM66 revealed a single peak of immunoreactive material exhibiting the same retention time as recombinant EM66. Immunocytochemical labelling showed that EM66-producing neurones are widely distributed in several hypothalamic regions, including the preoptic area, the suprachiasmatic, supraoptic, parvocellular paraventricular and arcuate nuclei, and the lateral hypothalamus. Food deprivation for 5 days induced a significant increase in the number of EM66-containing neurones within the arcuate nucleus (105% increase) and the parvocellular aspect of the paraventricular nucleus (115% increase), suggesting that EM66 could be involved in the control of feeding behaviour and/or the response to stress associated with fasting. Altogether, these data reveal the physiological plasticity of the EM66 system in the hypothalamus and implicate this novel peptide in the regulation of neuroendocrine functions.     

Amphibian melanotrophs as a model to analyze the secretory plasticity of endocrine cells

Precise regulation of hormone secretion from endocrine cells is of critical importance for the maintenance of animal homeostasis. This is partly enabled through the ability of endocrine cells to adapt dynamically their secretory activity to the physiological demands through complex functional changes. Such a secretory plasticity results from coordinated adaptive changes at several levels of cell function, including hormonal gene expression and biosynthesis, hormone processing, trafficking, storage and release, expression of membrane receptors, activation of signaling pathways, etc. Integration of all these processes at the single cell level defines the secretory status of each of the individual cells producing a given hormone, whose coordinated activity ultimately determines the response of the whole endocrine gland. This short review summarizes our most recent findings on the cellular and molecular elements and mechanisms underlying the secretory plasticity of endocrine cells, obtained from the analysis of distinct aspects of melanotroph cell function.     

Value of prenatal corticotherapy in the prevention of hyaline membrane disease in premature infants. Randomized prospective study

OBJECTIVE: The aim of the study was to determine the feasibility, the cost and the effects of antenatal maternal corticosteroid treatment on preventing respiratory distress syndrome in premature neonates of our population. SUBJECTS AND METHODS: Between January, 1, 1998 and June, 31, 1999, 118 pregnant women at 26-34 weeks' gestation and at a high risk of premature delivery, were prospectively randomized in 2 groups: group 1 received intramusculary 24 mg of betamethasone (12 mg every 24 hours), group 2 didn't receive antenatal corticosteroids. At birth, premature neonates were systematically examined by a neonatologist. RESULTS: 131 premature neonates were born (63 from group 1, 68 from group 2). The incidence and the degree of severity of respiratory distress syndrome, appeared substancially reduced (4.8% vs 27.9%) by the use of antenatal corticosteroids. Moreover, neonatal mortality due to respiratory distress syndrome was statistically less in group 1 than in group 2 (22.9% vs 57%). There was no significant difference in the occurrence of maternal or neonatal corticosteroid complications such as infection between treated group and control subjects. We estimated a potential annual savings of 21 thousands tunisian dinars, when the cost implications for antenatal corticosteroid therapy were estimated to 2 thousands tunisian dinars. CONCLUSION: Maternal administration of corticosteroids before preterm delivery results in a decrease in the incidence and severity of respiratory distress syndrome and a decrease in neonatal mortality rate among premature neonates born to treated versus untreated mothers at 26-34 weeks' gestation; added to an annual savings estimated to 21 thousands tunisian dinars.     

Relaxant effect of the calcitonin gene-related peptide (CGRP) on the nonpregnant and pregnant rat uterus. Comparison with vascular tissue

To explore the role of calcitonin gene-related peptide (CGRP) in rat pregnancy, we determined the density of myometrial CGRP-encoded nerve fibre terminals and examined, in an organ bath, the relaxant effect of the peptide on uterine strips near parturition. Comparisons were made with the uterus and aorta of nonpregnant rats. In the myometrium, CGRP immunoreactive nerve fibers were abundant in nonpregnant rats and scarce at the parturient stage. In the aorta there was no variation in the density of CGRP fibres with gestation. In nonpregnant rats only, CGRP relaxed spontaneous and tetrodotoxin (TTX)-sensitive electrically-evoked uterine contractions (EC₅₀ 40nM, E _max 80%). The effect was antagonized by CGRP[8-37] (pK _B 6.47) but was not affected by either blockers of nitric-oxid synthase or ATP-sensitive potassium channels. CGRP was also able to relax contractions evoked by direct depolarization of the cells (TTX-insensitive contractions) (EC₅₀ 2nM, E _max 70%). In aorta contracted with arginine vasopressin, CGRP-induced relaxation was the same in nonpregnant and parturient animals. It was antagonized by CGRP [8–37] (pK _B 6.90) and was abolished in presence of the nitric oxide synthase inhibitor Nω-nitro-l-arginine methyl ester (L-NAME). Amylin neither relaxed the uterus nor the aorta. In pregnant rats, the relaxant effect of CGRP on the uterus was limited on day 21 and was totally absent on day 22 of gestation. We conclude that the primary relaxant effect of CGRP on the uterus occurs at the level of myometrial smooth muscle cells. In the myometrium, gestation decreases CGRP innervation and impairs the relaxant responses to CGRP. Such changes are not observed in vascular tissues like aorta. Received: 24 September 1997 / Accepted: 16 December 1997     

Episousse: incidence of newly presenting seizures in children in the Region of Sousse, Tunisia

PURPOSE: To evaluate the incidence of newly presenting seizures in children in the area of Sousse, Tunisia. METHODS: From June 1, 1998, to May 31, 1999, all children aged 1 month to 15 years with first provoked and unprovoked seizures were included. Children with febrile seizures were excluded. All suspected cases were systematically referred to the Department of Functional Explorations of the Nervous System where a detailed questionnaire was filled out by a neurologist. All the patients underwent an EEG. Only 12 patients had a computed tomography (CT) scan. RESULTS: A total of 175 patients were included. Eighteen (10.3%) patients had acute symptomatic seizures, and 157 patients had unprovoked seizures. The incidence rate of first unprovoked seizures was 102.1/100,000. In this latter group, some epileptic syndromes were individualized on strict electroclinical criteria. CONCLUSIONS: However, nearly 75% of the cases remained cryptogenic, one of the major reasons that no predominant risk factor was identified in this population.     

The short-term impact of COVID-19 pandemic on spine surgeons: a cross-sectional global study

European Spine Journal - The outbreak of COVID-19 erupted in December 2019 in Wuhan, China. In a few weeks, it progressed rapidly into a global pandemic which resulted in an overwhelming burden on...     

Differential expression of secretogranin II and chromogranin A genes in the female rat pituitary through sexual maturation and estrous cycle

Secretogranin II (SgII) is a protein of pituitary secretory granules released by LHRH-stimulated gonadotrope cells. Estrogens and androgens are modulators of SgII release. Experiments were performed to determine the regulation of expression of the SgII gene in the female rat pituitary, during sexual maturation and according to the estrous cycle. Age- and cycle-related changes in SgII mRNA content were estimated through cytoplasmic slot blot; SgII content was determined by western blotting; maturation of the protein was controlled through [35S]sulfate labeling. Variations in chromogranin A (CgA), another protein of secretory granules, were analyzed in the same experimental conditions to assess the specificity of SgII regulation. The pituitary SgII concentration increased between days 7 and 21 (2.2-fold) and then declined to the initial 7-day-old value. Simultaneously, the CgA concentration went through a maximum between days 14 and 21 and then strongly dropped to barely detectable levels in the adult pituitary. The SgII mRNA concentration followed roughly the same pattern as the protein. Moreover, the sulfation level remained constant between days 14 and 60. These results demonstrated a regulatory mechanism operating, during sexual maturation, on the SgII gene and not on the protein processing or on storage/release steps. In the 4-day cycling females, the pituitary SgII mRNA and protein contents were the lowest during estrus. They then increased to their highest values in diestrus II. Moreover, the sulfation level of SgII was significantly higher during estrus than during any other stage. Due to its low content level, variations in pituitary CgA could not be demonstrated during the cycle.