Chantrigné – La Hamelinière

La deuxième campagne de fouille sur le site de l’Allée Couverte de la Hamelinière a permis de compléter un certain nombre d’informations recueillies en 2000. Tout d’abord, il se confirme qu’il n’y a pas (ou plus) de trace évidente de cairn structuré autour de l’armature mégalithique de la tombe ; tout au plus avons-nous repéré, par endroits, sur la face sud, un calage succinct de blocaille anarchique colmaté par de l’arène granitique enrichie en argile. Il se confirme aussi que les orthostate..

Saint-Mars-sur-la-Futaie – La Louvetière

La deuxième campagne de fouilles sur le site de « La Hutte aux Gabelous », s’est déroulée en 1992 du 9 juillet au 6 août, avec la collaboration de 27 fouilleurs. Aucun travail de restauration n’a été entrepris, en raison de l’incertitude demeurant quant à l’inclinaison des dalles du péristalithe. Le travail de fouille autour de l’aire rectangulaire ouverte l’an dernier a donc été poursuivi, et plus particulièrement sur deux secteurs : au sud-est, dans les bandes 23 et 26, à la recherche de la..

Saint-Mars-sur-la-Futaie – La Hutte aux Gabelous

La fouille et la restauration de la sépulture néolithique, à entrée latérale, du Néolithique final, ont été poursuivies en 1993, du 7 juillet au 6 août, cette dernière campagne étant exclusivement consacrée à la remise en état du monument. Les campagnes précédentes avaient montré que seule la partie nord-ouest du monument (environ les 3/5 de la longueur totale) pouvait être restaurée. Fig. 1 – Vue de la partie restaurée du monument Cliché : R. Bouillon. Le péristalithe a été redressé par end..

Pontmain – Les Rochers

La campagne de fouille conduite par R. Bouillon en 1991 dans le cadre d’une opération programmée pluriannuelle sur le dolmen de la Hutte aux Gabelous a permis de compléter le plan de ce monument mégalithique qui se compose d’une chambre allongée de 1,30 m de large et de 9 m de long, délimitée par 18 orthostats. Le tertre qui enveloppait la chambre funéraire, dont il subsiste une partie à l’ouest de la dalle de chevet, était ceinturé d’un péristalithe. Trois faces sont actuellement dégagées su..

Vautorte – Forêt de Mayenne, cote 197

R. Bouillon a poursuivi et achevé la fouille, commencée en 1984, du monument mégalithique de la cote 197 en forêt de Mayenne (Gallia Préhistoire, 28, 1985, p. 383). Il s’agit d’un édifice d’une longueur totale de 9,8 m, proche des allées couvertes du nord de l’Armorique. L’entrée se trouve à l’extrémité orientale ; sa largeur est de 0,8 m environ. Un élargissement progressif conduit à une chambre de 6 m de long, aux parois grossièrement parallèles, et d’une largeur maximale de 1,4 m. Derrière..

Vitamin D metabolites in captivity? Should we measure free or total 25(OH)D to assess vitamin D status?

There is general consensus that serum 25(OH)D is the best biochemical marker for nutritional vitamin D status. Whether free 25(OH)D would be a better marker than total 25(OH)D is so far unclear. Free 25(OH)D can either be calculated based on the measurement of the serum concentrations of total 25(OH)D, vitamin D-binding protein (DBP), albumin, and the affinity between 25(OH)D and its binding proteins in physiological situations. Free 25(OH)D can also be measured directly by equilibrium dialysis, ultrafitration or immunoassays. During the vitamin D workshop held in Boston in March 2016, a debate was organized about the measurements and clinical value of free 25(OH)D, and this debate is summarized in the present manuscript. Overall there is consensus that most cells apart from the renal tubular cells are exposed to free rather than to total 25(OH)D. Therefore free 25(OH)D may be highly relevant for the local production and action of 1,25(OH)2D. During the debate it became clear that there is a need for standardization of measurements of serum DBP and of direct measurements of free 25(OH)D. There seems to be very limited genetic or racial differences in DBP concentrations or (probably) in the affinity of DBP for its major ligands. Therefore, free 25(OH)D is strongly correlated to total 25(OH)D in most normal populations. Appropriate studies are needed to define the clinical implications of free rather than total 25(OH)D in normal subjects and in disease states. Special attention is needed for such studies in cases of abnormal DBP concentrations or when one could expect changes in its affinity for its ligands

Parathyroid hormone-stimulated calcium absorption in cTAL from vitamin D-deficient rabbits

Parathyroid hormone-stimulated calcium absorption in cTAL from vitamin D-deficient rabbits. Cortical thick ascending limbs of Henle's loop were dissected from the kidneys of chronically vitamin D-deficient or -replete rabbits and perfused in vitro. Unidirectional transepithelial calcium fluxes from lumen to bath were measured with 45Ca. The tubules were bathed in a solution containing 150mM sodium and perfused with a solution containing 60mM sodium to simulate conditions in the cortical thick ascending limb in vivo. Transepithelial voltages were equal across tubules from vitamin D-deficient and -replete rabbits. Likewise, baseline and parathyroid hormone-stimulated calcium fluxes were the same in tubules from the two groups. Because calcidiol and calcitriol were undetectable in the serum of the vitamin D-deficient rabbits, we suggest that neither of these endogenous vitamin D metabolites is essential in the regulation of calcium absorption in this portion of the rabbit nephron

NuSAP, a novel microtubule-associated protein involved in mitotic spindle organization

Here, we report on the identification of nucleolar spindle–associated protein (NuSAP), a novel 55-kD vertebrate protein with selective expression in proliferating cells. Its mRNA and protein levels peak at the transition of G2 to mitosis and abruptly decline after cell division. Microscopic analysis of both fixed and live mammalian cells showed that NuSAP is primarily nucleolar in interphase, and localizes prominently to central spindle microtubules during mitosis. Direct interaction of NuSAP with microtubules was demonstrated in vitro. Overexpression of NuSAP caused profound bundling of cytoplasmic microtubules in interphase cells, and this relied on a COOH-terminal microtubule-binding domain. In contrast, depletion of NuSAP by RNA interference resulted in aberrant mitotic spindles, defective chromosome segregation, and cytokinesis. In addition, many NuSAP-depleted interphase cells had deformed nuclei. Both overexpression and knockdown of NuSAP impaired cell proliferation. These results suggest a crucial role for NuSAP in spindle microtubule organization

Vitamin D Endocrine System and COVID-19. Treatment with Calcifediol

The COVID-19 pandemic is the greatest challenge facing modern medicine and public health systems. The viral evolution of SARS-CoV-2, with the emergence of new variants with in-creased infectious potential, is a cause for concern. In addition, vaccination coverage remains in-sufficient worldwide. Therefore, there is a need to develop new therapeutic options, and/or to optimize the repositioning of drugs approved for other indications for COVID-19. This may include the use of calcifediol, the prohormone of the vitamin D endocrine system (VDES) as it may have potential useful effects for the treatment of COVID-19. We review the aspects associating COVID-19 with VDES and the potential use of calcifediol in COVID-19. VDES/VDR stimulation may enhance innate antiviral effector mechanisms, facilitating the induction of antimicrobial peptides/autophagy, with a critical modulatory role in the subsequent host reactive hyperinflammatory phase during COVID-19: By decreasing the cytokine/chemokine storm, regulating the renin–angiotensin–bradykinin system (RAAS), modulating neutrophil activity and maintaining the integrity of the pulmonary epithelial barrier, stimulating epithelial repair, and directly and indirectly decreasing the increased coagulability and prothrombotic tendency associated with severe COVID-19 and its complications. Available evidence suggests that VDES/VDR stimulation, while maintaining optimal serum 25OHD status, in patients with SARS-CoV-2 infection may significantly reduce the risk of acute respiratory distress syndrome (ARDS) and severe COVID-19, with possible beneficial effects on the need for mechanical ventilation and/or intensive care unit (ICU) admission, as well as deaths in the course of the disease. The pharmacokinetic and functional characteristics of calcifediol give it superiority in rapidly optimizing 25OHD levels in COVID-19. A pilot study and several observational intervention studies using high doses of calcifediol (0.532 mg on day 1 and 0.266 mg on days 3, 7, 14, 21, and 28) dramatically decreased the need for ICU admission and the mortality rate. We, therefore, propose to use calcifediol at the doses described for the rapid correction of 25OHD deficiency in all patients in the early stages of COVID-19, in association, if necessary, with the new oral antiviral agents