Integrated Allosteric Model of Voltage Gating of Hcn Channels

Hyperpolarization-activated (pacemaker) channels are dually gated by negative voltage and intracellular cAMP. Kinetics of native cardiac f-channels are not compatible with HH gating, and require closed/open multistate models. We verified that members of the HCN channel family (mHCN1, hHCN2, hHCN4) also have properties not complying with HH gating, such as sigmoidal activation and deactivation, activation deviating from fixed power of an exponential, removal of activation “delay” by preconditioning hyperpolarization. Previous work on native channels has indicated that the shifting action of cAMP on the open probability (Po) curve can be accounted for by an allosteric model, whereby cAMP binds more favorably to open than closed channels. We therefore asked whether not only cAMP-dependent, but also voltage-dependent gating of hyperpolarization-activated channels could be explained by an allosteric model. We hypothesized that HCN channels are tetramers and that each subunit comprises a voltage sensor moving between “reluctant” and “willing” states, whereas voltage sensors are independently gated by voltage, channel closed/open transitions occur allosterically. These hypotheses led to a multistate scheme comprising five open and five closed channel states. We estimated model rate constants by fitting first activation delay curves and single exponential time constant curves, and then individual activation/deactivation traces. By simply using different sets of rate constants, the model accounts for qualitative and quantitative aspects of voltage gating of all three HCN isoforms investigated, and allows an interpretation of the different kinetic properties of different isoforms. For example, faster kinetics of HCN1 relative to HCN2/HCN4 are attributable to higher HCN1 voltage sensors' rates and looser voltage-independent interactions between subunits in closed/open transitions. It also accounts for experimental evidence that reduction of sensors' positive charge leads to negative voltage shifts of Po curve, with little change of curve slope. HCN voltage gating thus involves two processes: voltage sensor gating and allosteric opening/closing

Different Treatments of Symptomatic Angiomyolipomas of the Kidney: Two Case Reports

Development of more sensitive imaging techniques has caused an increase in the number of diagnosed small renal tumors. Approximately 2–3% of these lesions are proved to be angiomyolipomas (AML), a rare benign tumor of the kidney sometimes causing pain and hematuria. The most required approach is observation, but in the case of recurrent symptoms or larger tumors, which may cause bleeding, a more active treatment is required. We present two cases of symptomatic AML tumors of different sizes in the kidney: one treated with transarterial embolization (TAE), and the other with percutaneous cryoablation (CRA). The lesions were diagnosed on the basis of contrast-enhanced computed tomography (CT) scan and magnetic resonance imaging (MRI). Both treatments proved to be effective and safe for treating renal AMLs. A follow-up carried out, based on contrast-enhanced CT scan, confirmed complete treatment of AML and decreased lesion size. There are myriad minimally invasive approaches for the treatment of renal AMLs, and the preservation of renal function remains a priority. The most popular treatment option is the selective renal artery embolization. Owing to its limited invasiveness, CRA could be an attractive option for the preventive treatment of AML

Efficacy of an Augmented Reality Navigation System (SIRIO) for Percutaneous Computed Tomographic-Guided Pulmonary Ground-Glass Opacity Biopsies

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Percutaneous Ablative Treatment of Renal Tumors in a Solitary Kidney: A Single-Center Experience

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The Role of Ablative Techniques in Treatment of Lung Metastasis: Our Interventional Radiology Experience

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FISSIT (Fistula Surgery in Italy) study: A retrospective survey on the surgical management of anal fistulas in Italy over the last 15 years

Background: Surgical treatment of anal fistulas is still a challenge. The aims of this study were to evaluate the adoption and healing rates for the different surgical techniques used in Italy over the past 15 years. Methods: This was a multicenter retrospective observational study of patients affected by simple and complex anal fistulas of cryptoglandular origin who were surgically treated in the period 2003-2017. Surgical techniques were grouped as sphincter-cutting or sphincter-sparing and as technology-assisted or techno-free. All patients included in the study were followed for at least 12 months. Results: A total of 9,536 patients (5,520 simple; 4,016 complex fistulas) entered the study. For simple fistulas, fistulotomy was the most frequently used procedure, although its adoption significantly decreased over the years (P < .0005), with an increase in sphincter-sparing approaches; the overall healing rate in simple fistulas was 81.1%, with a significant difference between sphincter-cutting (91.9%) and sphincter-sparing (65.1%) techniques (P = .001). For complex fistulas, the adoption of sphincter-cutting approaches decreased, while sphincter-sparing techniques were mildly preferred (P < .0005). Moreover, there was a significant trend toward the use of technology-assisted procedures. The overall healing rate for complex fistulas was 69.0%, with a measurable difference between sphincter-cutting (81.1%) and sphincter-sparing (61.4%; P = .001) techniques and between techno-free and technology-assisted techniques (72.5% and 55.0%, respectively; P = .001). Conclusion: Surgical treatment of anal fistulas has changed, with a trend toward the use of sphincter-sparing techniques. The overall cure rate has remained stable, even if the most innovative procedures have achieved a lower success rate

Complete response for advanced liver cancer during sorafenib therapy: Case Report

<p>Abstract</p> <p>Background</p> <p>Hepatocellular carcinoma (HCC) is the fifth most common neoplasia in the world. In the past, treatment of advanced HCC with conventional antineoplastic drugs did not result in satisfactory outcomes: recently, in this patient population the oral multikinase inhibitor sorafenib has been able to induce a statistically significant improvement of overall survival. Similarly to other anti-angiogenic drugs employed in other tumour types, also sorafenib seldom induces the dimensional tumour shrinking usually observed with conventional cytotoxic drugs: data gathered from studies carried out with sorafenib and other competitors under development do not report any complete response in HCV-induced HCC.</p> <p>Case presentation</p> <p>An 84-year old man with a long-lasting history of chronic HCV hepatitis was referred to our Institution for an ultrasonography investigation of a focal hepatic lesion. To better characterize the liver disease and clearly define the diagnosis of the focal hepatic lesion, the patient was hospitalized in our department. Laboratory and instrumental investigations confirmed the clinical picture of HCV-related liver cirrhosis and identified a hepatic lesion of about 6 cm featuring infiltrating HCC with thrombosis of the portal trunk. Due to the advanced stage of the disease, therapy with sorafenib 400 mg bid was started. Right from one month after the treatment was started, a reduction of alpha-fetoprotein level was observed which, by the third month, turned down within the normal limits. In addition the CT scan showed 50% reduction of the neoplastic lesion along with canalization of the portal trunk. At the sixth month the normalization of the alpha-fetoprotein level at the lower limit of normality was confirmed and the MRI showed complete disappearance of the neoplasia. In addition a reduction of a metallo-proteinase serum level was obserdved. At the twelfth month a further MRI confirmed complete response had been maintained. At present the patient is in a follow-up program to evaluate the duration of the complete response.</p> <p>Conclusions</p> <p>This case is worth mentioning since, to the best of our knowledge, it represents the first evidence of complete response to sorafenib in an elderly patient with advanced HCV-related HCC.</p

Influence of maternal and social factors as predictors of low birth weight in Italy

Abstract Background The purpose of this study is to provide insight into the determinants of low birth weight (LBW) in Italy. Methods The study was carried out in a non-teaching hospital in Catanzaro (Italy). All LBW and very LBW newborns (200) were included in the study and a random sample of 400 newborns weighing ≥ 2500 g was selected. Data were collected from the delivery certificates during one year. Smoking activity of mother and familiar and/or social support during pregnancy was gathered through telephone interviews. Results Overall annual LBW rate was 11.8%. Among LBW newborn there were 125 preterm and 75 term. Younger mothers, those who smoked during pregnancy, and had fewer prenatal care visits were more likely to deliver a LBW child; moreover, preterm newborns, delivered by caesarean section, and twin or multiple birth were significantly more likely to have a LBW. The comparison of very LBW ( Conclusion Several modifiable factors affect the risk of LBW, even when universal access to health care is freely available, but socio-economic status appears to correlate only to very LBW.</p

Brain Health Services: organization, structure, and challenges for implementation. A user manual for Brain Health Services—part 1 of 6

Dementia has a devastating impact on the quality of life of patients and families and comes with a huge cost to society. Dementia prevention is considered a public health priority by the World Health Organization. Delaying the onset of dementia by treating associated risk factors will bring huge individual and societal benefit. Empirical evidence suggests that, in higher-income countries, dementia incidence is decreasing as a result of healthier lifestyles. This observation supports the notion that preventing dementia is possible and that a certain degree of prevention is already in action. Further reduction of dementia incidence through deliberate prevention plans is needed to counteract its growing prevalence due to increasing life expectancy. An increasing number of individuals with normal cognitive performance seek help in the current memory clinics asking an evaluation of their dementia risk, preventive interventions, or interventions to ameliorate their cognitive performance. Consistent evidence suggests that some of these individuals are indeed at increased risk of dementia. This new health demand asks for a shift of target population, from patients with cognitive impairment to worried but cognitively unimpaired individuals. However, current memory clinics do not have the programs and protocols in place to deal with this new population. We envision the development of new services, henceforth called Brain Health Services, devoted to respond to demands from cognitively unimpaired individuals concerned about their risk of dementia. The missions of Brain Health Services will be (i) dementia risk profiling, (ii) dementia risk communication, (iii) dementia risk reduction, and (iv) cognitive enhancement. In this paper, we present the organizational and structural challenges associated with the set-up of Brain Health Services