DNA damage response activation in mouse embryonic fibroblasts undergoing replicative senescence and following spontaneous immortalization

Primary mouse embryonic fibroblasts (MEFs) are a popular tool for molecular and cell biology studies. However, when MEFs are grown in vitro under standard tissue culture conditions, they proliferate only for a limited number of population doublings (PD) and eventually undergo cellular senescence. Presently, the molecular mechanisms halting cell cycle progression and establishing cellular senescence under these conditions are unclear. Here, we show that a robust DNA damage response (DDR) is activated when MEFs undergo replicative cellular senescence. Senescent cells accumulate senescence-associated DDR foci (SDFs) containing the activated form of ATM, its phosphorylated substrates and \u3b3H2AX. In senescent MEFs, DDR markers do not preferentially accumulate at telomeres, the end of linear chromosomes. It has been observed that proliferation of MEFs is extended if they are cultured at low oxygen tension (3% O2). We observed that under these conditions, DDR is not observed and senescence is not established. Importantly, inactivation of ATM in senescent MEFs allows escape from senescence and progression through the S-phase. Therefore, MEFs undergoing cellular senescence arrest their proliferation due to the activation of a DNA damage checkpoint mediated by ATM kinase. Finally, we observed that spontaneously immortalized proliferating MEFs display markers of an activated DDR, indicating the presence of chromosomal DNA damage in these established cell lines

Miti e altre storie. La grande decorazione a Brescia 1680-1830

Un atlante storico-artistico illustrato: cinquanta palazzi e ville del bresciano rivelano la ricchezza del loro apparato decorativo. Il libro \ue8 l\u2019esito di un lungo e complesso lavoro di schedatura e ricerca, promosso dall\u2019Universit\ue0 degli Studi di Verona in collaborazione con il Centro di ricerca \u201cRossana Bossaglia\u201d e dedicato alla grande decorazione settecentesca a tema profano presente nei palazzi di Brescia e in alcune ville poste a corona della citt\ue0. A tutti gli edifici sono dedicate ampie schede di approfondimento, corredate da un ricco apparato fotografico

Risk of Guillain-Barr\ue9 syndrome after 2010-2011 influenza vaccination

Influenza vaccination has been implicated in Guillain Barr\ue9 Syndrome (GBS) although the evidence for this link is controversial. A case-control study was conducted between October 2010 and May 2011 in seven Italian Regions to explore the relation between influenza vaccination and GBS. The study included 176 GBS incident cases aged 6518 years from 86 neurological centers. Controls were selected among patients admitted for acute conditions to the Emergency Department of the same hospital as cases. Each control was matched to a case by sex, age, Region and admission date. Two different analyses were conducted: a matched case-control analysis and a self-controlled case series analysis (SCCS). Case-control analysis included 140 cases matched to 308 controls. The adjusted matched odds ratio (OR) for GBS occurrence within 6 weeks after influenza vaccination was 3.8 (95 % CI: 1.3, 10.5). A much stronger association with gastrointestinal infections (OR = 23.8; 95 % CI 7.3, 77.6) and influenza-like illness or upper respiratory tract infections (OR = 11.5; 95 % CI 5.6, 23.5) was highlighted. The SCCS analysis included all 176 GBS cases. Influenza vaccination was associated with GBS, with a relative risk of 2.1 (95 % CI 1.1, 3.9). According to these results the attributable risk in adults ranges from two to five GBS cases per 1,000,000 vaccinations