The veins contain approximately 70% of total blood volume and are 30 times more compliant than arteries; therefore, changes in blood volume within the veins are associated with relatively small changes in venous pressure. The terms venous capacity, compliance, and stressed and unstressed volumes are defined. Decreases in flow into a vein are associated with decreases in intravenous pressure and...

Sir,?I have read with interest the article on ' Taking blood for transfusion' by Lieut-Colonel S. D. S. Greval, i.m.s., and Dr. S. N. Chandra, in the January issue of the Gazette. As blood transfusion is still in its infancy in India, suggestions for making it easy to perform with safety both to donor and recipient are to be welcomed. I wish to make the following observations:? 1. Complaints re...

Cerebral blood volume and intracranial pressure may be modified by influences on cerebral veins. The known adrenergic innervation of cerebral veins and their sensitivity to norepinephrine raised the question, whether pial veins can be selectively influenced through adrenoceptors in vivo. Therefore, alpha] and alpha2 adrenoceptor agonists and antagonists were locally injected into the perivascul...

Cerebral blood volume and intracranial pressure may be modified by influences on cerebral veins. The known adrenergic innervation of cerebral veins and their sensitivity to norepinephrine raised the question, whether pial veins can be selectively influenced through adrenoceptors in vivo. Therefore, alpha 1 and alpha 2 adrenoceptor agonists and antagonists were locally injected into the perivasc...

Varicose veins affect approximately one-third of the adult population and result in significant psychological, physical, and financial burden. Nevertheless, the molecular pathogenesis of varicose vein formation remains unidentified. Venous hypertension exerted on veins of the lower extremity is considered the principal factor in varicose vein formation. The role of mechanotransduction of the hi...

Introduction The kidneys are paired organs in the abdomen that are essential and responsible for filtering blood, removing waste, controlling body fluids, and regulating electrolyte and hormonal homeostasis. In order to properly perform these important functions the kidneys must have adequate blood supply. Typically, each kidney has a hilum that receives blood from a single renal artery from th...

BACKGROUND Multiple sclerosis (MS) is a chronic disease with not well understood etiology. Recently, a possible association of MS with compromised venous outflow from the brain and spinal cord has been studied (chronic cerebrospinal venous insufficiency - CCSVI). Angioplasties of internal jugular veins (IJV) and azygous vein (AV) have given promising results, with improvements in patients' clin...

Little is known regarding the changes in blood oxygen tension (P(O2)) with changes in brain function. This work aimed to measure the blood P(O2) in surface arteries and veins as well as tissue with evoked somato-sensory stimulation in the anesthetized rat. Electrical stimulation of the forepaw induced average increases in blood flow of 44% as well as increases in the tissue P(O2) of 28%. More i...

BACKGROUND Venous diseases including varicose veins and chronic venous insufficiency are one of the most important pathogenic factors worldwide. High prevalence of varicose veins and its complications is an emerging problem in the twenty-first century. This study aimed to determine the prevalence and associated risk factors of varicose veins in female hairdressers in Shahroud, north of Iran in ...

renal vein thrombosis (rvt) is the most frequent vascular abnormality in newborns, but rarely seen in adults. rvt is an acute problem, and diagnostic and therapeutic approaches should be done immediately. surgical thrombectomy is not a rational approach and the treatment of choice is conservative management and thrombolytic therapy. we present a 45 years old male patient with chronic renal vein...