Variations In Renal Excretion Research Articles

Assessment of the diurnal variations in urinaryhomovanillic and vanillylmandelic acid excretion for the diagnosis and follow-up of patients with neuroblastoma

The diurnal variation of urinary homovanillic acid (HVA) and vanillylmandelic acid (VMA) was studied in neuroblastoma patients and in a control group. Urinary HVA and VMA levels in four sequential 6-hour urine collections within a 24-hour period were compared. HVA and VMA levels were expressed in μg/mg of urinary creatinine (UCr) and in mg/6h specimens. No statistically significant variations between the four time intervals were found when expressed in μg/mg UCr or mg/6h. The small variations that exist in the excretion of HVA and VMA during different periods of the day are due to variations in renal excretion rather than variations in production. The results from this study indicate that a random urine sample should be as good as a 24-hour collection for diagnosis and follow-up of neural crest tumors.

Diurnal variations in renal excretion of electrolytes, uric acid and total amino nitrogen in various renal diseases and in essential hypertension

Results of earlier investigations and observations from clinical practice indicate that diurnal variations in renal excretion of different urinary constituents diminish when kidney is damaged. Consequently the diagnostic value of the so-called “clearance indices” ( C x ) has been studied. Performed as 24-h tests, C x was estimated every 3 h taking into account the maximum oscillations of C x ( VC max ). The tests were performed in 63 patients who were classified into the following groups: ( I) acute glomerulonephritis (9); ( 2) chronic glomcrulonephritis (13); ( 3) pyelonephritis (8); ( 4) nephrosis (5); ( 5) other renal diseases (low nephron syndrome, polycystic degeneration of the kidney, post-nephrectomy states, etc.) (9); ( 6) essential hypertension (19); ( 7) controls (healthy medical students) (10). The following conclusions were drawn: ( 1) Kidney functional disturbances in most cases are characterised by decrease in C x and VC x max. (2) In the healthy controls low water intake causes a decrease of C x and VC x max.

Life situations, behaviour, attitudes, emotions, and renal excretion of fluid and electrolytes—I: Method of study

The purpose of the present investigation was to study variations in renal excretion occuring during the course of daily activities, and to ascertain the feasibility of studying such variations in fluid and electrolyte excretion under circumtances of ordinary daily “routine” rather than under the limiting circumtances of controlled laboratory procedure. Despite obvious difficulties involved in such a procedure, this type of study proved feasible. Wide variations in excretion rates of wate, sodium, and potassium were observed in the five healthy subjects studied. The range of variation observed at any time of day was similar in any one of the subjects whether he had been fasting or had a high level of intake preceding of the collection period. In one subject with sodium intake continuouslym higher than in the others, sodium excretion was also generally higher. However, sudden and transient changes in intake, whether omission of a meal or ingestion of an unusually large meal, had relatively little effect on the excretion rates observed. Many of the variations observed could not be correlated with changes in intake of water, sodium, or potassium, with activity or sleep, or with any combination of these.