Identifying conformational changes with site-directed spin labeling reveals that the GTPase domain of HydF is a molecular switch

[FeFe]-hydrogenases catalyse the reduction of protons to hydrogen at a complex 2Fe[4Fe4S] center called H-cluster. The assembly of this active site is a multistep process involving three proteins, HydE, HydF and HydG. According to the current models, HydF has the key double role of scaffold, upon which the final H-cluster precursor is assembled, and carrier to transfer it to the target hydrogenase. The X-ray structure of HydF indicates that the protein is a homodimer with both monomers carrying two functional domains: a C-terminal FeS cluster-binding domain, where the precursor is assembled, and a N-terminal GTPase domain, whose exact contribution to cluster biogenesis and hydrogenase activation is still elusive. We previously obtained several hints suggesting that the binding of GTP to HydF could be involved in the interactions of this scaffold protein with the other maturases and with the hydrogenase itself. In this work, by means of site directed spin labeling coupled to EPR/PELDOR spectroscopy, we explored the conformational changes induced in a recombinant HydF protein by GTP binding, and provide the first clue that the HydF GTPase domain could be involved in the H-cluster assembly working as a molecular switch similarly to other known small GTPases

Exploring iron-binding to human frataxin and to selected Friedreich ataxia mutants by means of NMR and EPR spectroscopies

The neurodegenerative disease Friedreich ataxia results from a deficiency of frataxin, a mitochondrial protein. Most patients have a GAA expansion in the first intron of both alleles of frataxin gene, whereas a minority of them are heterozygous for the expansion and contain a mutation in the other allele. Frataxin has been claimed to participate in iron homeostasis and biosynthesis of FeS clusters, however its role in both pathways is not unequivocally defined. In this work we combined different advanced spectroscopic analyses to explore the iron-binding properties of human frataxin, as isolated and at the FeS clusters assembly machinery. For the first time we used EPR spectroscopy to address this key issue providing clear evidence of the formation of a complex with a low symmetry coordination of the metal ion. By 2D NMR, we confirmed that iron can be bound in both oxidation states, a controversial issue, and, in addition, we were able to point out a transient interaction of frataxin with a N-terminal 6his-tagged variant of ISCU, the scaffold protein of the FeS clusters assembly machinery. To obtain insights on structure/function relationships relevant to understand the disease molecular mechanism(s), we extended our studies to four clinical frataxin mutants. All variants showed a moderate to strong impairment in their ability to activate the FeS cluster assembly machinery in vitro, while keeping the same iron-binding features of the wild type protein. This supports the multifunctional nature of frataxin and the complex biochemical consequences of its mutations.Fil: Bellanda, Massimo. Università di Padova; ItaliaFil: Maso, Lorenzo. Università di Padova; ItaliaFil: Doni, Davide. Università di Padova; ItaliaFil: Bortolus, M.. Università di Padova; ItaliaFil: De Rosa, E.. Università di Padova; ItaliaFil: Lunardi, Federica. Università di Padova; ItaliaFil: Alfonsi, Arianna. Università di Padova; ItaliaFil: Noguera, Martín Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Herrera, Maria Georgina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Santos, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Carbonera, Donatella. Università di Padova; ItaliaFil: Costantini, Paola. Università di Padova; Itali

Prognostic value of normal sodium levels in patients with metastatic renal cell carcinoma receiving tyrosine kinase inhibitors

Background: Although serum sodium concentration, particularly hyponatremia, has been shown to be a prognostic marker of survival in metastatic renal cell carcinoma (mRCC), the impact of normal sodium levels has not been investigated. Herein, we investigate the influence of normonatremia in mRCC patients treated with tyrosine kinase inhibitors (TKIs). Materials and methods: For this retrospective study, the clinical and biochemical data of patients treated with first-line TKIs for mRCC were available from seven Italian cancer centers. We collected natremia levels at baseline and first evaluation after treatment excluding patients with sodium levels outside the normal range (<135 or >145 mEq/L). The remaining patients were subdivided into two groups according to the median sodium value: natremia patients with <140 mEq/L (n = 132) and baseline natremia patients with ≥140 mEq/L (n = 185). Subsequently, we analyzed the impact of sodium levels on response rate (RR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS). PFS and OS were estimated through the Kaplan–Meier method, and differences between groups were examined by the log-rank test. Univariate and multivariate Cox regression analyses were applied to evaluate the prognostic factors for PFS and OS. Results: Of the 368 patients, 317 were included in the analysis, 73.1% were men, and the median age was 67 years (range 36–89). When comparing patients with baseline natremia ≥140 mEq/L (n = 185) to patients with natremia <140 mEq/L (n = 132), the PFS was 15 vs. 10 months (p < 0.01) and the OS was 63 vs. 36 months, respectively (p = 0.02). On the first evaluation, patients with serum sodium ≥140 mEq/L had longer PFS (15 vs. 10 months, p < 0.01) and OS (70 vs. 32 months, p < 0.01) than patients with levels <140 mEq/L. Moreover, clinical outcomes showed a significant improvement in patients with natremia ≥140 mEq/L compared with patients with levels <140 mEq/L both at baseline and first evaluation: PFS was 19 vs. 11 months (p < 0.01) and OS was 70 vs. 36 months (p < 0.01), respectively. Conclusions: To the best of our knowledge, this is the first study to investigate the impact of normonatremia in mRCC. We found that serum sodium levels <140 mEq/L at baseline and first assessment are independently associated with worse PFS and OS in mRCC patients treated with TKIs in the first-line setting

Effect of systemic therapies or best supportive care after disease progression to both nivolumab and cabozantinib in metastatic renal cell carcinoma: The Meet‐Uro 19BEYOND study

Background Nivolumab and cabozantinib are currently approved agents in metastatic renal cell carcinoma (mRCC) but there are no data available for patients progressing to both treatments. The aim of this study was to compare active therapeutic options and best supportive care (BSC) after progression to nivolumab and cabozantinib in mRCC. Methods In this retrospective study, we selected 50 patients from eight Italian centers. The primary endpoint of the study was the overall survival (OS) of patients on active treatment versus BSC. Secondary endpoints were the progression-free survival (PFS) and objective response rate (ORR). The efficacy of active therapy was also investigated. Results After progression to both nivolumab and cabozantinib, 57.1% of patients were given active treatment (mainly everolimus and sorafenib) while 42.9% received BSC. The median OS was 13 months (95% CI: 4-NR) in actively treated patients and 3 months (95% CI: 2–4) in BSC patients (p = 0.001). Patients treated with sorafenib had better disease control than those treated with everolimus (stable disease: 71.4% vs. 16.7%, progression disease: 14.3% vs. 58.3%; p = 0.03), with no significant differences in PFS (5 and 3 months, 95% CI: 1–6 vs. 2–5; p = 0.6) and OS (12 and 4 months, 95% CI: 3-NR vs. 2-NR; p = 0.2). Conclusion After treatment with both nivolumab and cabozantinib, the choice of a safe active systemic therapy offered better outcomes than BSC

Colorectal Cancer Stage at Diagnosis Before vs During the COVID-19 Pandemic in Italy

IMPORTANCE Delays in screening programs and the reluctance of patients to seek medical attention because of the outbreak of SARS-CoV-2 could be associated with the risk of more advanced colorectal cancers at diagnosis. OBJECTIVE To evaluate whether the SARS-CoV-2 pandemic was associated with more advanced oncologic stage and change in clinical presentation for patients with colorectal cancer. DESIGN, SETTING, AND PARTICIPANTS This retrospective, multicenter cohort study included all 17 938 adult patients who underwent surgery for colorectal cancer from March 1, 2020, to December 31, 2021 (pandemic period), and from January 1, 2018, to February 29, 2020 (prepandemic period), in 81 participating centers in Italy, including tertiary centers and community hospitals. Follow-up was 30 days from surgery. EXPOSURES Any type of surgical procedure for colorectal cancer, including explorative surgery, palliative procedures, and atypical or segmental resections. MAIN OUTCOMES AND MEASURES The primary outcome was advanced stage of colorectal cancer at diagnosis. Secondary outcomes were distant metastasis, T4 stage, aggressive biology (defined as cancer with at least 1 of the following characteristics: signet ring cells, mucinous tumor, budding, lymphovascular invasion, perineural invasion, and lymphangitis), stenotic lesion, emergency surgery, and palliative surgery. The independent association between the pandemic period and the outcomes was assessed using multivariate random-effects logistic regression, with hospital as the cluster variable. RESULTS A total of 17 938 patients (10 007 men [55.8%]; mean [SD] age, 70.6 [12.2] years) underwent surgery for colorectal cancer: 7796 (43.5%) during the pandemic period and 10 142 (56.5%) during the prepandemic period. Logistic regression indicated that the pandemic period was significantly associated with an increased rate of advanced-stage colorectal cancer (odds ratio [OR], 1.07; 95%CI, 1.01-1.13; P = .03), aggressive biology (OR, 1.32; 95%CI, 1.15-1.53; P < .001), and stenotic lesions (OR, 1.15; 95%CI, 1.01-1.31; P = .03). CONCLUSIONS AND RELEVANCE This cohort study suggests a significant association between the SARS-CoV-2 pandemic and the risk of a more advanced oncologic stage at diagnosis among patients undergoing surgery for colorectal cancer and might indicate a potential reduction of survival for these patients

La forza sociale della memoria. Esperienze, culture, confini.

La memoria \ue8 un campo di ricerca smisurato. Il percorso che si svolge in questo volume propone di sondare gli infiniti recessi di una dimensione problematica. Sorta a partire da un intenso confronto tra discipline e dipartimenti diversi, questa raccolta di studi non \ue8 semplicemente un lavoro a pi\uf9 voci, \ue8 una specie di viaggio compiuto insieme, trattenendo talvolta il respiro nei momenti in cui l\u2019aria si faceva rarefatta, per via di inevitabili passaggi nella speculazione pi\uf9 ardita, o \u2013 pi\uf9 spesso \u2013 per via dell\u2019atmosfera irrespirabile che caratterizza alcuni momenti chiave della nostra storia. Ci sono traumi che fondano il comportamento sociale, che lo attraversano come una corrente carsica, in attesa di cristallizzarsi in riti, forme d\u2019arte, stili di consumo, o magari in ossessioni violente. La memoria \ue8 una "forza" che spinge gli attori ad agire, pi\uf9 che a pensare. Perci\uf2 in questo libro si tratta s\uec di culture, ovvero modalit\ue0 comuni di vita sociale,ma anche di confini e di esperienze, l\ue0 dove il fatto sociale condiviso da un gruppo si confronta con quello di altri. Mai innocente,mai definitiva, lamemoria si presta ad un approccio complesso e dinamico, di cui queste pagine offrono una possibile traccia

La forza sociale della memoria. Esperienze, culture, confini

Il volume racchiude alcuni interventi tenuti in occasione di due convegni, altrettante testimonianze di collaborazione tra l'università di Bergamo e quella di Veron

Cryoablation of para-Hisian and mid-septal accessory pathways: long-term outcomes of a specific stepwise cryoablation protocol

Background: Although cryoablation (CA) of septally located accessory pathways (APs) is an established treatment for Wolff-Parkinson-White syndrome, its major limitation is the lack of data regarding long-term follow-up (FU). The present study sought to investigate long-term outcomes of a specific CA protocol targeting para-Hisian (P-H) and mid-septal (M-S) APs. Methods: 26 patients who previously underwent CA of PH or MS APs from 2004 to 2014, were prospectively considered to receive a follow-up (FU) during 2021. All subjects received an outpatient control visit, performing an exercise stress test and a 24-h ECG Holter monitoring. Results: Acute success was achieved in 22 patients (85%). One case of recurrence was reported at short-term FU. Long-term FU, performed after a mean time of 150 ± 37 months, did not show ventricular preexcitation recurrences, with a success rate of 81%, and without late adverse events. Symptoms reduction (12% vs. 96%, p<.001) and lower rates of antiarrhythmic drug use (12% vs. 62%, p<.001) were observed at long term-FU with respect to baseline. This clinical outcome was detected also among patients who underwent unsuccessful CA at baseline. Conclusions: Our CA protocol confirmed remarkable safety and efficacy throughout a longterm FU. Significant clinical improvement in terms of antiarrhythmic therapy discontinuation and symptoms reduction was also shown among patients who experienced acute failure of CA