The Ricci flow on generalized Wallach spaces

We consider the asymptotic behavior of the normalized Ricci flow on generalized Wallach spaces that could be considered as special planar dynamical systems. All non symmetric generalized Wallach spaces can be naturally parametrized by three positive numbers $a_1, a_2, a_3$. Our interest is to determine the type of singularity of all singular points of the normalized Ricci flow on all such spaces. Our main result gives a qualitative answer for almost all points $(a_1,a_2,a_3)$ in the cube $(0,1/2]\times (0,1/2]\times (0,1/2]$.Comment: 18 pages, 3 figures, comments are welcom

Orexin-A exerts equivocal role in atherosclerosis process depending on the duration of exposure : in vitro study

Orexin-A is a peptide hormone that plays a crucial role in feeding regulation and energy homeostasis. Diurnal intermittent fasting (DIF) has been found to increase orexin-A plasma levels during fasting hours, while Ramadan fasting which resembles DIF, has led to beneficial effects on endothelial function. Herein, we aimed to investigate the effects of orexin-A on the expression of molecules involved in the atherogenesis process: Monocyte chemoattractant protein-1 (MCP-1), matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) and tissue inhibitor of metalloproteinase-1 and 2 (TIMP-1 and TIMP-2), in human aortic endothelial cells (HAECs). HAECs were incubated with orexin-A at concentrations of 40 ng/mL, 200 ng/mL and 400 ng/mL for 6, 12 and 24 h. The mRNA levels of MCP-1, MMP-2, MMP-9, TIMP-1, and TIMP-2 and orexin-1 receptor were measured by real-time qPCR. We also evaluated the MMP-2, p38, phospho-p38, NF-κΒ/p65 as well as TIMP-1 protein levels by Western blot and ELISA, respectively. MMP-2 activity was measured by gelatin zymography. Short-term 6-h incubation of HAECs with orexin-A at a high concentration (400 ng/mL) decreased MCP-1, MMP-2 expression, MMP-2/TIMP-1 ratio (p < 0.05), and MMP-2 activity, while incubation for 24 h increased MCP-1, MMP-2 expression (p < 0.05), MMP-2/TIMP-1 and MMP-2/TIMP-2 ratio (p < 0.01 and p < 0.05, respectively) as well as MMP-2 activity. The dual effects of orexin-A are mediated, at least in part, via regulation of p38 and NF-κΒ pathway. Orexin-A may have an equivocal role in atherosclerosis process with its effects depending on the duration of exposure

Hypokalemia: A clinical update

Hypokalemia is a common electrolyte disturbance, especially in hospitalized patients. It can have various causes, including endocrine ones. Sometimes, hypokalemia requires urgent medical attention. The aim of this review is to present updated information regarding: (1) the definition and prevalence of hypokalemia, (2) the physiology of potassium homeostasis, (3) the various causes leading to hypokalemia, (4) the diagnostic steps for the assessment of hypokalemia and (5) the appropriate treatment of hypokalemia depending on the cause. Practical algorithms for the optimal diagnostic, treatment and follow-up strategy are presented, while an individualized approach is emphasized

Sociodemographic and Lifestyle Statistics of Oldest Old People (>80 Years) Living in Ikaria Island: The Ikaria Study

Background. There are places around the world where people live longer and they are active past the age of 100 years, sharing common behavioral characteristics; these places (i.e., Sardinia in Italy, Okinawa in Japan, Loma Linda in California and Nicoya Peninsula in Costa Rica) have been named the “Blue Zones”. Recently it was reported that people in Ikaria Island, Greece, have also one of the highest life expectancies in the world, and joined the “Blue Zones”. The aim of this work work was to evaluate various demographic, lifestyle and psychological characteristics of very old (>80 years) people participated in Ikaria Study. Methods. During 2009, 1420 people (aged 30+) men and women from Ikaria Island, Greece, were voluntarily enrolled in the study. For this work, 89 males and 98 females over the age of 80 yrs were studied (13% of the sample). Socio-demographic, clinical, psychological and lifestyle characteristics were assessed using standard questionnaires and procedures. Results. A large proportion of the Ikaria Study's sample was over the age of 80; moreover, the percent of people over 90 were much higher than the European population average. The majority of the oldest old participants reported daily physical activities, healthy eating habits, avoidance of smoking, frequent socializing, mid-day naps and extremely low rates of depression. Conclusion. Modifiable risk factors, such as physical activity, diet, smoking cessation and mid-day naps, might depict the “secrets” of the long-livers; these findings suggest that the interaction of environmental, behavioral together with clinical characteristics may determine longevity. This concept must be further explored in order to understand how these factors relate and which are the most important in shaping prolonged life

Differential effects of EPA vs. DHA on postprandial vascular function and the plasma oxylipin profile in men

Our objective was to investigate the impact of EPA versus DHA, on arterial stiffness and reactivity, and underlying mechanisms (with a focus on plasma oxylipins), in the postprandial state. In a 3-arm cross-over acute test meal trial men (n=26, 35-55y) at increased CVD risk, received a high fat (42.4g) test meal providing 4.16 g of EPA or DHA or control oil in random order. At 0 h and 4 h, blood samples were collected to quantify plasma fatty acids, LCn-3PUFAs derived oxylipins, nitrite and hydrogen sulfide and serum lipids and glucose. Vascular function was assessed using blood pressure, Reactive Hyperaemia Index (RHI), Pulse Wave Velocity and Augmentation Index (AIx). The DHA-rich oil significantly reduced AIx by 13% (P=0.047) with the decrease following EPA-rich oil intervention not reaching statistical significance. Both interventions increased EPA and DHA derived oxylipins in the acute postprandial state, with an (1.3 fold) increase in 19,20-DiHDPA evident after DHA intervention (P < 0.001). In conclusion, a single dose of DHA significantly improved postprandial arterial stiffness as assessed by AIx, which if sustained would be associated with a significant decrease in CVD risk. The observed increases in oxylipins provide a mechanistic insight for the AIx effect

Late Tricuspid Regurgitation as a Result of Rheumatic Tricuspid Disease in a Patient With Prosthetic Mitral Valve. Combined Two-Dimensional and Real-Time Three-Dimensional Transthoracic Echocardiographic Assessment

We herein present the case of a 65-year-old lady with late tricuspid regurgitation 15 years after successful mitral valve replacement due to severe mitral stenosis of rheumatic origin. She presented to our department complaining of fatigue which worsened over the last 6 months. Transthoracic echocardiographic examination including both 2D and real time 3D modalities revealed severe tricuspid regurgitation and the patient was scheduled for tricuspid annuloplasty. A propos with this case, a brief review of the literature is provided highlighting the key points of this topic