Nocturia

Nocturia (from the Greek nyx - night and ouron - urine), a term proposed by Pehu (1903) to denote a pathological symptom consisting in the predominant excretion of urine during nighttime hours. In normal conditions, a person excretes 2/3 to 4/5 of the total amount of liquid eliminated by the kidneys during 12 daytime hours; under certain pathological conditions, however, the nighttime portion of urine may more than double the daytime portion. N. is observed mainly in insufficiency of cardiac activity and in kidney diseases (chronic diffuse glomerulonephritis and more rarely acute, and especially nephrosclerosis); it has also been described in cirrhosis of the liver, hypertrophy of the prostate, pyelitis, diabetes insipidus, and diseases of the thyroid gland. The pathogenesis of N. has not yet been definitely clarified. Most authors point to weakening of cardiac work as the most frequent and main factor in the development of N: if during the day the diseased heart cannot cope with the work falling to its share and this leads to venous congestion in the kidneys and a decrease in diuresis, then at night during sleep, with a decrease in muscle tone, elimination of daytime psychological irritants, reduction to a minimum of all vital functions, etc., the conditions for cardiac work improve. This leads to an improvement in blood circulation in general and blood circulation in the kidneys in particular; as a result - an increase in nighttime diuresis, N. This explanation cannot be accepted unconditionally, since an improvement in the entire blood circulation during sleep cannot yet be considered established, as it is based only on theoretical considerations. Along with the mentioned factor in the pathogenesis of N., even in persons with cardiac insufficiency, the weakening under the influence of sleep of pathologically increased tonic contraction of kidney vessels apparently also plays a role, as well as possible changes in the conditions of absorption of tissue fluid during nighttime hours. These latter factors - in particular the decrease in the tone of kidney vessels at night with improvement in blood supply to the kidneys as a result (Volhard, Klein and others) - are assigned the main and even exclusive role in the pathogenesis of those prolonged, lasting for years N. (for example, in the initial stages of nephrosclerosis), where no clear signs of cardiac weakness are noted. Those kidney disorders with damage to kidney vessels, in which N. is observed, usually lead to considerable difficulties for cardiac work and can subsequently lead to cardiac insufficiency; to separately determine in such cases the role of kidney and cardiac or vascular factors in the development of N. often appears very difficult. Volhard considers nocturia with excretion of large amounts of urine also during daytime hours as N. of predominantly kidney origin (in these cases there is usually more or less loss by the kidney of its ability to adapt to changing conditions of its work and to vary the composition and amount of urine at different times of day); daytime oliguria in N. according to Volhard is a sign of predominantly cardiac origin of the latter. Pehu and Schoenewald accept cardiac origin for all cases of so-called kidney N., assuming the presence of hidden cardiac insufficiency here. Klein particularly emphasizes the role in the pathogenesis of N. of the function of capillary cells and lymphatic pathways participating in the absorption of tissue fluid, resp. in its delivery to the kidneys, considering N. a symptom of disturbance of the function of these cells regardless of whether this disturbance is connected with insufficiency of cardiac activity or with fluctuations in vascular tone. The horizontal position of the body and bed warmth, to which some authors are inclined to attach great importance in the development of N., apparently play only an auxiliary role in its origin. N., standing mainly in connection with weakening of cardiac activity, can disappear with strengthening of the cardiac muscle and decrease in fluid intake; 'kidney' N. has a persistent character and does not decrease with a decrease in the amount of fluid introduced. Sometimes nocturia, not clearly expressed under ordinary conditions of examination of the patient, becomes much more distinct when applying the so-called one-day 'overloading' of the kidneys (Mehrbelastung of German authors) - a certain addition of food and change in the character of the fluid introduced (Schlayer and Hedinger, Zimnitsky and others).-The clinical significance of nocturia consists mainly in that in some diseases developing gradually and imperceptibly (weakening of the cardiac muscle of various origins, nephroscleroses, diffuse glomerulonephritis without functional insufficiency of the kidneys) it is an early symptom appearing before the typical clinical picture of the corresponding disease develops, which allows timely adoption of appropriate therapeutic measures. The transition of unstable nocturia into constant one indicates a progressing pathological process.

B. Ilyinsky. NILBLAUSULFATE, nilblaussulfate, sulfate of the basic oxazine dye nilblau; a powder easily soluble in water and in alcohol. In aqueous solutions it dissociates into a blue salt, which stains the nuclei and protoplasm of cells blue, and a red base soluble in fat, which is stained red. With the help of fat or chloroform, the base can be removed from the blue solution of the dye. In fatty acids, the base again forms a blue salt and the corresponding color. Neutral fats and cholesterol esters are stained red by N., phosphatides, fatty acids, soaps - blue. For good results, fresh material is required; prolonged fixation of the latter in warm formalin leads to uniform staining of lipid droplets in blue. Transitions in shades of colors from blue to red constitute a certain inconvenience of the dye (see Lipoids).