Circadian clock and vascular disease.

Cardiovascular functions, including blood pressure and vascular functions, show diurnal oscillation. Circadian variations have been clearly shown in the occurrence of cardiovascular events such as acute myocardial infarction. Circadian rhythm strongly influences human biology and pathology. The identification and characterization of mammalian clock genes revealed that they are expressed almost everywhere throughout the body in a circadian manner. In contrast to the central clock in the suprachiasmatic nucleus (SCN), the clock in each tissue or cell is designated as a peripheral clock. It is now accepted that peripheral clocks have their own roles specific to each peripheral organ by regulating the expression of clock-controlled genes (CCGs), although the oscillation mechanisms of the peripheral clock are similar to that of the SCN. However, little was known about how the peripheral clock in the vasculature contributes to the process of cardiovascular disorders. The biological clock allows each organ or cell to anticipate and prepare for changes in external stimuli. Recent evidence obtained using genetically engineered mice with disrupted circadian rhythm showed a novel function of the internal clock in the pathogenesis of endothelial dysfunction, hypertension and hemostasis. Loss of synchronization between the central and peripheral clock also contributes to the pathogenesis of cardiovascular diseases, as restoration of clock homeostasis could prevent disease progression. Identification of CCGs in each organ, as well as discovery of tools to manipulate the phase of each biological clock, will be of great help in establishing a novel chronotherapeutic approach to the prevention and treatment of cardiovascular disorders

Flow cytometric analysis of circadian changes in platelet activation using anti-GMP-140 monoclonal antibody

The hemostatic activity of blood shows a circadian variation with a higher frequency of acute coronary events in the morning. The thrombotic tendency of blood is influenced by many factors, including platelets. Diurnal changes of in vivo platelet activation were investigated by whole blood flow cytometry in 10 young healthy male volunteers using anti-GMP-140 (anti-alpha-granule membrane protein 140 kD) monoclonal antibody at 3h intervals from 06:00 to 24:00. We also studied circulating platelet aggregates to investigate whether there exists a similarity between the results of these methods. Results of flow cytometric analysis indicate that there is an increase in platelet activation during the period from 06:00 to 09:00. Platelet activation then decreases gradually during the period from noon to midnight. These changes are accompanied by a similar trend in circulating platelet aggregates. This suggests that GMP-140 expression on platelets is synchronized with or followed by platelet aggregate formation in vivo, and increased platelet activation may predispose individuals to thrombosis at this time

Pulsatile vs. continuous flow

Earlier left ventricular assist devices (LVADs) were volume displacement pumps (VDPs) that delivered pulsatile flow. However, due to improved survival rates of rotary blood pumps (RBPs), they are now the preferred device. Originally, RBPs operated at a constant speed and therefore delivered flow continuously with an absent or diminished pulse. Although RBPs were an improvement to the previous VDPs, the delivery of continuous flow has led to secondary complications, such as vascular and aortic valve dysfunction and gastrointestinal bleeding. Therefore, research has been made toward pulsatile RBPs by rapidly modulating pump speed. However, deriving pulsatile flow with RBPs has not been without controversy. Issues of debate have included the quantification of an adequate pulse and the influence of blood trauma and power consumption when generating a pulse with a RBP. Meanwhile, the pulsatility controversy has also expanded to total artificial heart and extracorporeal membrane oxygenator (ECMO) support. Nevertheless, commercial developments have been made toward combining the benefits of improved durability and survival rates of RBPs with a pulsing mechanism for mechanical circulatory support

Primary thyroid lymphoma: case series with literature review.

Non Hodgkin's lymphomas (NHL) of the thyroid are rare thyroid neoplasms. The majority of histopathologic types are extranodal marginal zone B-cell lymphoma of mucosa associated lymphoid tissue (MALT) type and, diffuse large B-cell lymphoma (DLBCL). Most of them arise in a background of Hashimoto's thyroiditis and patients mostly present with a rapidly enlarging thyroid mass and with pressure symptoms. Treatment depends on the histological subtype and stage of the disease and includes radiotherapy and chemotherapy. The prognosis usually is favorable with proper treatment. Herein, we discuss the clinical diagnosis and treatment of thyroid lymphoma