1. Distal blockade by simultaneous administration of ethacrynic acid and chlorothiazide was performed in healthy subjects whose extracellular fluid was expanded by iso-osmotic sodium chloride or bicarbonate. The results obtained were compared with those from non-expanded subjects (Ardaillou & Fillastre, 1969). 2. By this technique urine approximates in composition to proximal tubular fluid and ...

Clathrin-independent endocytosis is an umbrella term for a variety of endocytic pathways that internalize numerous cargoes independently of the canonical coat protein Clathrin [1, 2]. Electron-microscopy studies have defined the pleiomorphic CLathrin-Independent Carriers (CLICs) and GPI-Enriched Endocytic Compartments (GEECs) as related major players in such uptake [3, 4]. This CLIC/GEEC pathwa...

A great number of cells are acidic compared to their environment (1). Changes in the pH of extracellular fluid are important primarily as they affect hydrogen ion activity within the cell. However, cellular hydrogen ion activity is dependent upon a number of factors, so that it is impossible to predict cellular pH from knowledge of extracellular pH alone (2, 3). Since the interior of most cells...

DURING the loss or gain of edema the composition of the extracellular fluid remains remarkably constant despite the large ehanges in volume. A number of studies have indicated that the renal excretion of body water and electrolytes does not completely aceount for this constancy. In studies of edema loss, electrolytes and water were not lost in the same proportions that exist in extraeellular fl...

The role of plasma free fatty acids (FFA) in the transport of fatty acids from host tissues to Ehrlich ascites carcinoma in mice was studied. [9,10-(3)H] Palmitate complexed to mouse serum (albumin) was injected either intraperitoneally or intravenously into unanesthetized tumor-bearing mice. The incorporation of radioactivity into tumor extracellular fluid FFA, tumor cell FFA, neutral lipid, p...

Magnesium (Mg(2+)) plays an important role in the neural system, and yet scarcely any research has quantitatively analyzed the link between endogenous Mg(2+) level and memory. Using our original technique, we measured erythrocyte intracellular ionized Mg(2+) concentration (RBC [Mg(2+)]i), which linearly correlated to recognition and spatial memory in normal aging rats. In the brain, RBC [Mg(2+)...

It is well known that the loss of extracellular electrolyte may contribute to or even produce cardiovascular collapse. This is manifest in its most striking form in the crisis of Addison's disease (1), in diabetic acidosis and coma (2, 3) and in patients losing large amounts of fluid from the gastrointestinal tract (4, 5). In these conditions the losses of the sodium ion, the chloride ion, and ...

Cerebrospinal fluid (CSF) is a major part of the central nervous system (CNS) extracellular fluid, and fine regulation of its composition is vital to the brain’s health. Although CSF dynamics has been studied for an entire century, many of its aspects are still insufficiently understood. Today there are two hypotheses (1,2) on CSF physiology: a) traditional hypothesis and b) microcirculatory/mi...

The brain is unique among virtually all somatic organs in its lack of a conventional lymphatic vasculature. In the periphery, the lymphatic circulation facilitates the clearance of extracellular proteins and excess fluid from the interstitium, a role critical to tissue homeostasis and function. Yet within the brain, despite its complex architecture and high metabolic activity and neural cells’ ...