A High Incidence of Meiotic Silencing of Unsynapsed Chromatin Is Not Associated with Substantial Pachytene Loss in Heterozygous Male Mice Carrying Multiple Simple Robertsonian Translocations

Meiosis is a complex type of cell division that involves homologous chromosome pairing, synapsis, recombination, and segregation. When any of these processes is altered, cellular checkpoints arrest meiosis progression and induce cell elimination. Meiotic impairment is particularly frequent in organisms bearing chromosomal translocations. When chromosomal translocations appear in heterozygosis, the chromosomes involved may not correctly complete synapsis, recombination, and/or segregation, thus promoting the activation of checkpoints that lead to the death of the meiocytes. In mammals and other organisms, the unsynapsed chromosomal regions are subject to a process called meiotic silencing of unsynapsed chromatin (MSUC). Different degrees of asynapsis could contribute to disturb the normal loading of MSUC proteins, interfering with autosome and sex chromosome gene expression and triggering a massive pachytene cell death. We report that in mice that are heterozygous for eight multiple simple Robertsonian translocations, most pachytene spermatocytes bear trivalents with unsynapsed regions that incorporate, in a stage-dependent manner, proteins involved in MSUC (e.g., γH2AX, ATR, ubiquitinated-H2A, SUMO-1, and XMR). These spermatocytes have a correct MSUC response and are not eliminated during pachytene and most of them proceed into diplotene. However, we found a high incidence of apoptotic spermatocytes at the metaphase stage. These results suggest that in Robertsonian heterozygous mice synapsis defects on most pachytene cells do not trigger a prophase-I checkpoint. Instead, meiotic impairment seems to mainly rely on the action of a checkpoint acting at the metaphase stage. We propose that a low stringency of the pachytene checkpoint could help to increase the chances that spermatocytes with synaptic defects will complete meiotic divisions and differentiate into viable gametes. This scenario, despite a reduction of fertility, allows the spreading of Robertsonian translocations, explaining the multitude of natural Robertsonian populations described in the mouse

SLXL1, a novel acrosomal protein, interacts with DKKL1 and is involved in fertilization in mice

BACKGROUND: Spermatogenesis is a complex cellular developmental process which involves diverse families of genes. The Xlr (X-linked, lymphocyte regulated) family includes multiple members, only a few of which have reported functions in meiosis, post-meiotic maturation, and fertilization of germ cells. Slx-like1 (Slxl1) is a member of the Xlr family, whose expression and function in spermatogenesis need to be elucidated. METHODOLOGY/PRINCIPAL FINDINGS: The mRNA and protein expression and localization of Slxl1 were investigated by RT-PCR, Western blotting and immunohistochemistry in different tissues and at different stages of spermatogenesis. The interacting partner of SLXL1 was examined by co-immunoprecipitation and co-localization. Assessment of the role of SLXL1 in capacitation, acrosome reaction, zona pellucida binding/penetration, and fertilization was carried out in vitro using blocking antisera. The results showed that Slxl1 mRNA and protein were specifically expressed in the testis. SLXL1 was exclusively located in the acrosome of post-meiotic germ cells and interacts with DKKL1 (Dickkopf-like1), which is an acrosome-associated protein and plays an important role in fertilization. The rates of zona pellucida binding/penetration and fertilization were significantly reduced by the anti-SLXL1 polyclonal antiserum. CONCLUSIONS/SIGNIFICANCE: SLXL1 is the first identified member of the XLR family that is associated with acrosome and is involved in zona pellucid binding/penetration and subsequent fertilization. These results, together with previous studies, suggest that Xlr family members participate in diverse processes from meiosis to fertilization during spermatogenesis

Secondary surgical decompression of the inferior alveolar nerve after overfilling of endodontic sealer into the mandibular canal: Case report and literature review

International audienceThe authors report the case of a 43-year-old woman who underwent endodontic treatment of the right second mandibular molar with substantial extrusion of endodontic material into the mandibular canal. The patient presented at the Department of Oral and Maxillofacial Surgery with a persistent total anaesthesia of the lower lip and chin after two months. 2D panoramic view and 3D CT-scan examination highlighted the overfilling into the mandibular canal with a more than 50% stenosis of the canal and a consequently significant compression of the dental pedicle. A surgical decompression of the inferior alveolar nerve was performed through an inferior vestibular approach, using PiezoSurgery®. The tooth was conserved. After a period of 8days, paraesthesia of the lower lip and chin appeared. Thermoalgic sensitivity was recovered at 1month. At 3months postoperatively, the patient had recovered protopathic and epicritic sensitivity. Dental prosthetic rehabilitation was finally achieved one year postoperatively. The authors discuss the physiopathology of nervous injuries during dental procedures, and further strategies in the case of persistent neurologic disorders

Physician experts in diabetes are natural team leaders for managing diabetic patients with foot complications. A position statement from the Italian diabetic foot study group

Diabetic foot syndrome (DFS) is a complex disease. The best outcomes are reported with the multi-disciplinary team (MDT) approach, where each member works collaboratively according to his/her expertise. However, which health provider should act as the team leader (TL) has not been determined. The TL should be familiar with the management of diabetes, related complications and comorbidities. He/she should be able to diagnose and manage foot infections, including prompt surgical treatment of local lesions, such as abscesses or phlegmons, in an emergent way in the first meeting with the patient. According to the Organization for Economic Co-operation and Development (OECD) reports, Italy is one of countries with a low amputation rate in diabetic patients. Many factors might have contributed to this result, including 1)the special attention directed to diabetes by the public health system, which has defined diabetes as a "protected disease", and accordingly, offers diabetic patients, at no charge, the best specialist care, including specific devices, and 2)the presence of a network of diabetic foot (DF) clinics managed by diabetologists with medical and surgical expertise. The health care providers all share a "patient centred model" of care, for which they use their internal medicine background and skills in podiatric surgery to manage acute or chronic needs in a timely manner. Therefore, according to Italian experiences, which are fully reported in this document, we believe that only a skilled diabetologist/endocrinologist should act as a TL. Courses and university master's degree programmes focused on DF should guarantee specific training for physicians to become a TL

4-Heteroaryl Substituted Amino-3,5-Dicyanopyridines as New Adenosine Receptor Ligands: Novel Insights on Structure-Activity Relationships and Perspectives

A new set of amino-3,5-dicyanopyridines was synthesized and biologically evaluated at the adenosine receptors (ARs). This chemical class is particularly versatile, as small structural modifications can influence not only affinity and selectivity, but also the pharmacological profile. Thus, in order to deepen the structure–activity relationships (SARs) of this series, different substituents were evaluated at the diverse positions on the dicyanopyridine scaffold. In general, the herein reported compounds show nanomolar binding affinity and interact better with both the human (h) A1 and A2A ARs than with the other subtypes. Docking studies at hAR structure were performed to rationalize the observed affinity data. Of interest are compounds 1 and 5, which can be considered as pan ligands as binding all the ARs with comparable nanomolar binding affinity (A1AR: 1, Ki = 9.63 nM; 5, Ki = 2.50 nM; A2AAR: 1, Ki = 21 nM; 5, Ki = 24 nM; A3AR: 1, Ki = 52 nM; 5, Ki = 25 nM; A2BAR: 1, EC50 = 1.4 nM; 5, EC50 = 1.12 nM). Moreover, these compounds showed a partial agonist profile at all the ARs. This combined AR partial agonist activity could lead us to hypothesize a potential effect in the repair process of damaged tissue that would be beneficial in both wound healing and remodeling