The Bitcoin as a Virtual Commodity: Empirical Evidence and Implications.

The present work investigates the impact on financial intermediation of distributed ledger technology (DLT), which is usually associated with the blockchain technology and is at the base of the cryptocurrencies' development. "Bitcoin" is the expression of its main application since it was the first new currency that gained popularity some years after its release date and it is still the major cryptocurrency in the market. For this reason, the present analysis is focused on studying its price determination, which seems to be still almost unpredictable. We carry out an empirical analysis based on a cost of production model, trying to detect whether the Bitcoin price could be justified by and connected to the profits and costs associated with the mining effort. We construct a sample model, composed of the hardware devices employed in the mining process. After collecting the technical information required and computing a cost and a profit function for each period, an implied price for the Bitcoin value is derived. The interconnection between this price and the historical one is analyzed, adopting a Vector Autoregression (VAR) model. Our main results put on evidence that there aren't ultimate drivers for Bitcoin price; probably many factors should be expressed and studied at the same time, taking into account their variability and different relevance over time. It seems that the historical price fluctuated around the model (or implied) price until 2017, when the Bitcoin price significantly increased. During the last months of 2018, the prices seem to converge again, following a common path. In detail, we focus on the time window in which Bitcoin experienced its higher price volatility; the results suggest that it is disconnected from the one predicted by the model. These findings may depend on the particular features of the new cryptocurrencies, which have not been completely understood yet. In our opinion, there is not enough knowledge on cryptocurrencies to assert that Bitcoin price is (or is not) based on the profit and cost derived by the mining process, but these intrinsic characteristics must be considered, including other possible Bitcoin price drivers.

Correlation between baseline characteristics and clinical outcomes in a large population of diabetes patients treated with liraglutide in a real-world setting in Italy.

PURPOSE: Treatment with liraglutide in randomized controlled trials is associated with significant reductions in glycated hemoglobin (HbA1c) and weight loss in type 2 diabetes patients. The aim of this retrospective observational study was to investigate correlations of glycemic control and weight outcomes with baseline characteristics of patients starting liraglutide in outpatient clinics in Italy. METHODS: Type 2 diabetes patients were followed from baseline to 4, 8, and 12 months. Changes in glycemic parameters, weight, blood pressure, and lipids were assessed. Subanalyses were performed according to baseline characteristics. Multivariate linear and logistic regressions were used to assess correlations between glycemic efficacy, weight reduction, and liraglutide discontinuation after 12 months and baseline characteristics. FINDINGS: Four hundred and eighty-one patients were included. Mean (SD) age at baseline was 57.3 (9.2) years, diabetes duration was 9.5 (6.8) years, weight was 106.7 (20.8) kg, body mass index (BMI; calculated as kg/m(2)) was 37.1 (6.6), HbA1c was 8.7% (1.3%), fasting plasma glucose was 168.5 (45.3) mg/dL; 38.2% were treated previously with insulin and 52.2% were treated with metformin alone. After 12 months, mean (SD) changes were HbA1c -1.2% (1.4%), fasting plasma glucose -28.3 (41.1) mg/dL, weight -3.5 (5.8) kg, BMI -1.3 (2.1), waist circumference -2.6 (6.7) cm (all, P < 0.001). Drop in weight and HbA1c did not differ between baseline BMI classes ≤30 or >30. Weight loss was unchanged among diabetes duration quartiles, and HbA1c reduction was significantly greater in patients with ≤4 years of diabetes duration (P = 0.01). Non-insulin-treated patients reached HbA1c ≤7% significantly more often than treated patients (44.2% vs 21.2%; odds ratio = 2.94; P < 0.001) and had significantly greater weight loss (-4.5 [8.2] kg vs -2.6 [5.4] kg; P = 0.03). Patients on metformin reached HbA1c target more frequently than others (43.1% vs 29.7%; odds ratio = 1.80; 95% CI, 1.05-3.07). Significant positive determinants for HbA1c reduction after 12 months were baseline HbA1c, age, and prior metformin monotherapy, and weight loss at 12 months was positively correlated with baseline weight, and negatively correlated with prior insulin treatment. Overall, 5.0% of patients interrupted liraglutide before the 12th month due to lack of glycemic control; they were less frequently treated with metformin only before liraglutide (29.2% vs 50.2%; P = 0.04). IMPLICATIONS: Treatment with liraglutide in a real-world setting is associated with low therapy failure, good glycemic response, weight loss, and improvement in systolic blood pressure and lipid profile. The HbA1c drop did not differ among baseline BMI classes, indicating that efficacy is maintained in patients with lower BMI. The probability of reaching HbA1c ≤7% was significantly higher in patients previously treated with metformin alone and without any previous insulin. This could reinforce the hypothesis that better results with liraglutide could be achieved in patients after early metformin failure.

Dapsone hydroxylamine induces premature removal of human erythrocytes by membrane reorganization and antibody binding.

BACKGROUND AND PURPOSE: N-hydroxylation of dapsone leads to the formation of the toxic hydroxylamines responsible for the clinical methaemoglobinaemia associated with dapsone therapy. Dapsone has been associated with decreased lifespan of erythrocytes, with consequences such as anaemia and morbidity in patients treated with dapsone for malaria. Here, we investigated how dapsone and/or its hydroxylamine derivative (DDS-NHOH) induced erythrocyte membrane alterations that could lead to premature cell removal. EXPERIMENTAL APPROACH: Erythrocytes from healthy donors were subjected to incubation with dapsone and DDS-NHOH for varying times and the band 3 protein tyrosine-phosphorylation process, band 3 aggregation, membrane alteration and IgG binding were all examined and compared with erythrocytes from two patients receiving dapsone therapy. KEY RESULTS: The hydroxylamine derivative, but not dapsone (the parent sulphone) altered membrane protein interactions, leading both to aggregation of band 3 protein and to circulating autologous antibody binding, shown in erythrocytes from patients receiving dapsone therapy. The band 3 tyrosine-phosphorylation process can be used as a diagnostic system to monitor membrane alterations both in vitro, assessing concentration and time-dependent effects of DDS-NHOH treatment, and in vivo, evaluating erythrocytes from dapsone-treated patients, in resting or oxidatively stimulated conditions. CONCLUSIONS AND IMPLICATIONS: DDS-NHOH-induced alterations of human erythrocytes can be directly monitored in vitro by tyrosine-phosphorylation level and formation of band 3 protein aggregates. The latter, together with antibody-mediated labelling of erythrocytes, also observed after clinical use of dapsone, may lead to shortening of erythrocyte lifespan.

Band 3 tyr-phosphorylation in human erythrocytes from non-pregnant and pregnant women.

Pregnancy is associated with changes in circulating red blood cells, mainly involving band 3 protein and membrane lipid peroxidation. Membrane band 3 is a multifunctional protein containing four Tyr-phosphorylatable residues which modulate the physiological status of erythrocytes by regulating glycolysis, cell shape and membrane transport. Erythrocytes from nine pregnant and 12 age-matched non-pregnant healthy women were subjected to oxidative and hyperosmotic stress conditions and the extent of band 3 Tyr-phosphorylation and membrane Syk recruitment as a membrane marker were evaluated. Results indicated that, in pregnancy, red blood cells show a decrease in band 3 Tyr-phosphorylation and a clear-cut rearrangement of band 3 protein within the membrane. In fact, band 3 shows a decrease in high molecular weight aggregates (HMWA), with different subdivision between Triton-soluble and -insoluble compartments, and an increase in proteolytic fragments. In conclusion, it is demonstrated that pregnancy is associated with membrane adjustments which reduce the sensitivity of erythrocytes to both oxidative and osmotic stress. Band 3 Tyr-phosphorylation is proposed as a new parameter in the evaluation of erythrocyte membrane arrangement.

Band 3 tyr-phosphorylation in normal and glucose-6-phospate dehydrogenase-deficient human erythrocytes.

Haemolysis is usually episodic in glucose-6-phosphate dehydrogenase (G6PD) deficiency, often triggered by a period of oxidative stress. In the present work, we investigate a possible biochemical mechanism underlying the enhanced susceptibility of G6PD deficient red blood cells (RBC) to oxidative stress. We analysed eight male subjects with Mediterranean glucose-6P-dehydrogenase deficiency (G6PDd), class II, for their ability in phosphorylating erythrocyte membrane band 3 following oxidative and osmotic stress. Our findings show that this sensitivity is connected to an early membrane band 3 Tyr-phosphorylation in the presence of diamide. However, since both Syk, and Lyn kinases, and SHP-2 phosphatase, mostly implicated in the band 3 P-Tyr level regulation, are alike in content and activity in normal and patient erythrocytes, an alteration in the membrane organization is likely the cause of the anomalous response to the oxidant. We report, in fact, that hypertonic-induced morphological change in G6PDd erythrocyte induces a higher membrane band 3 Tyr-phosphorylation, suggesting a pre-existing membrane alteration, likely due to the chronic lowering of the redox systems in patients. We also report that 1-chloro-2,4-dinitrobenzene-pre-treatment of normal red cells can alter the normal protein-protein and protein-membrane interaction under hypertonic rather than oxidative stress, thus partially resembling the response in patients, and that RBC may utilize a wider range of redox defence, under oxidative conditions, including, but not exclusively, NADPH and glutathione. On the whole, these results would encourage a different approach to the evaluation of the effects of pharmacological administration to patients, giving more attention to the possible drug-induced membrane alteration evidenced by the abnormal band 3 Tyr-phosphorylation.