Diagnostic value of the water deprivation test in the polyuria-polydipsia syndrome.

OBJECTIVE: Diabetes insipidus (DI) and primary polydipsia (PP) are characterised by polyuria and polydipsia. It is crucial to differentiate between these two disorders since the treatment is different. The aim of this study was to evaluate the diagnostic value of the short and an extended variant of the water deprivation test (WDT) and of measuring urinary vasopressin (AVP) in patients with polyuria and polydipsia. DESIGN: A retrospective, single-centre study based on WDTs performed between 2004 and 2014 including 104 consecutive patients with the polyuria-polydipsia syndrome. During a strict water deprivation, weight, urinary osmolality, urinary vasopressin and specific gravity were collected until one of the following was reached: i) >3% weight reduction, ii) Urinary specific gravity >1.020 or, urinary osmolality >800 mOsm/L, iii) Intolerable adverse symptoms such as excessive thirst. RESULTS: Out of 104 patients (67 women, 37 men), 21 (20%) were diagnosed with DI and 83 (80%) with PP. The median (interquartile range; range) test duration was 14 hours (10-16; 3-36) in patients with DI and 18 hours (14-24; 7-48) in patients with PP (P=0.011). Of those diagnosed with PP, 22 (26%) did not reach urinary specific gravity >1.020 nor urine osmolality >800 mOsm/L. Urine AVP did not overlap between patients with PP and patients with central DI. CONCLUSIONS: The short WDT is of limited value in the diagnostic work-up of polydipsia and polyuria and a partial DI may have been missed in every fourth patient diagnosed with PP. Urinary AVP has excellent potential in discriminating PP from central DI.

Effect of chronic inhibition of converting enzyme on renal handling of salt and water: a study on a pediatric population.

BACKGROUND/AIMS: The effect of angiotensin-converting enzyme inhibition (ACEi) is amply documented in several pathological conditions. However, there are few reports about the effect of chronic ACEi on salt and water balance.The present work evaluates the effect of chronic ACEi on salt and water balance in a population of children receiving enalaprilchronically in order to reduce albuminuria elicited by auremic hemolytic syndrome. METHODS: Nine children aged from 9 to 19 years with normal glomerular filtration rate, normotension and with urinary concentration capacity preserved were treated with enalapril with doses ranging between 0.1 and 0.30 mg/kg/day. Diuresis, urinary absolute and fractional excretion of Na(+), K(+) and urea, creatinine clearance,osmolal clearance and tubular water reabsorption were measured under three experimental procedures: (1)with free access to water; (2) with a water load and (3) with water restriction. In the last group urinary antidiuretic hormone(ADH) was measured. These tests were performed ina paired way, just before starting ACEi treatment and after 6 months of enalapril treatment. RESULTS: Enalapril treatment diminished the urinary concentration capacity without affecting Na(+) and K(+) urinary excretion. Creatinine clearance was not modified except in the condition of water load where a fall in it was found after ACEi. ADH increased after enalapril treatment in children under water restriction. CONCLUSION: In these children chronic ACEi decreases urinary concentration capacity.

Early experience in humans is associated with changes in neuropeptides critical for regulating social behavior.

The formation of social attachments is a critical component of human relationships. Infants begin to bond to their caregivers from the moment of birth, and these social bonds continue to provide regulatory emotional functions throughout adulthood. It is difficult to examine the interactions between social experience and the biological origins of these complex behaviors because children undergo both brain development and accumulate social experience at the same time. We had a rare opportunity to examine children who were reared in extremely aberrant social environments where they were deprived of the kind of care-giving typical for our species. The present experiment in nature provides insight into the role of early experience on the brain systems underlying the development of emotional behavior. These data indicate that the vasopressin and oxytocin neuropeptide systems, which are critical in the establishment of social bonds and the regulation of emotional behaviors, are affected by early social experience. The results of this experiment suggest a potential mechanism whose atypical function may explain the pervasive social and emotional difficulties observed in many children who have experienced aberrant care-giving. The present findings are consistent with the view that there is a critical role for early experience in the development of the brain systems underlying basic aspects of human social behavior.

Urinary excretion of immunoreactive vasopressin in prepubertal children. Lack of correlation with urinary excretion of immunoreactive neurophysins.

The excretion of immunoreactive vasopressin (AVP) and neurophysins was determined in 24 h urine samples from 62 normal healthy children of various ages. Five groups of children were selected: group I (n = 7, aged 2 to 3 years), group II (n = 13, aged 3 to 5 years), group III (n = 16, aged 5 to 7 years), group IV (n = 16, aged 7 to 9 years), group V (n = 10, aged 9 to 11 years). The method used for urine AVP determination consisted of an extraction using a procedure slightly modified from that of Miller and Moses [14], coupled to a radioimmunoassay. The following urinary AVP excretions were obtained: group I mean: 70.8 ng/m2/24 h range: 51-150 ng, group II mean: 54.1 ng/m2/24 h range: 17-113.6 ng, group III mean: 55.2 ng/m2/24 h range: 18-106 ng, group IV mean: 39.9 ng/m2/24 h range: 11.7-77.9 ng, group V mean: 39.4 ng/m2/24 h range: 25.8-64 ng. The excretion of AVP was significantly correlated to the daily urinary osmolality (P less than 0.001) whether expressed in ng/24 h (r = 0.41) o rin ng/m2/24 h (r = 0.4.7). Neurophysins excretion ranging between 7 and 1,278 ng/24H is too variable to allow interpretation.

Urinary excretion of neurophysins in patients with kidney disease.

The mean rate of excretion of neurophysins in the urine of 16 patients with kidney disease but without tubular dysfunction was 0.48 +/- 0.14 (S.E.M.) ng/min, whereas the rate in 16 patients with tubular dysfunction was 3.64 +/- 1.56 ng/min (significantly different; 2P less than 0.01). In the whole group of 32 patients there was a relationship (r = 0.57) between the rate of excretion of neurophysins in the urine and the clearance of lysozyme. The increased rate of urinary excretion of neurophysins observed in some patients with kidney disease therefore appears to be related to a disorder of renal tubular function. It is shown that the raised levels of neurophysins observed in the serum of some patients with kidney disease are not attributable to a decrease in the urinary clearance of neurophysins.

Clearance and metabolism of neurophysins by rat kidney.

The half-life in the circulation of 125I-labelled porcine neurophysins, injected intravenously into rats, was determined. The radioactivity in blood collected at intervals after injection was characterized as neurophysin by polyacrylamide gel electrophoresis. The half-life of neurophysin I was 1-5 plus or minus 0-1 (S.E.M.) min and that of neurophusin II was 1-7 plus or minus 0-1 min. The metabolic clearance rate of neurophysin I and neurophysin II was 1-9 plus or minus 0-1 and 1-3 plus or minus 0-2 ml/min/200 g respectively. Clearance from the circulation was due to both equilibration with the extravescular space and rapid specific accumulation by the kidney. The neurophysins were filtered at the glomerulus. Most of the neurophysin takken up by the kidney was incorporated into lysosomes, probably in the proximal tubule and degraded to low-molecular-weight metabolites which appeared in urine and which represented the principle mode of excretion of neurophysins.

[Interactions between a progestational derivative (norethisterone acetate) and ethinyl estradiol on urinary elimination of neurophysin, ocytocin, and vasopressin and on the blood level of neurophysin I and II in normal human beings]. / Interactions entre un dérivé progestatif (acétate de noréthistérone) et l'éthinyl oestradiol sur l'élimination urinaire de neurophysine, d'ocytocine et de vasopressine immunoréactives et sur le taux de neurophysine sérique I et II chez l'homme normal

PIP: Neurophysin 1 (a peptide associated with antidiuretic homone, ADH), ADH, and oxytocin were measured in serum or urine of 3 men who took 10 mcg ethinyl estradiol with 5 mg norethisterone acetate twice daily for 6 days and in 3 who took the estrogen only. Neurophysin in plasma was determined by radioimmunoassy, and individually by starch gel electrophoresis, extraction, and assay. Total urine neurophysin was measured by radioimmunoassy. ADH and oxytocin were quantitated by column chromatography and radioimmunoassy. With both steroids, there was no change in neurophysin, ADH, or oxytocin. Ethinyl estradiol alone increased urinary neurophysin from 112.3 to 595 ng/hour (n.s.), oxytocin from 41-132 ng/hour (p less than .005), and ADH from 9.7-57.2 ng/hour (p less than .01). As in pregnant women compared to normal women, estrogen treatment stimulated plasma neurophysin 1 more than neurophysin 2 in these subjects. These results confirm those found in rats.^ieng