Water transport is mediated by two distinct pathways, diffusional and channel-mediated water transport. The first molecular water channel was identified from human erythrocytes in 1992. Genetically-related proteins from other mammalian tissues have subsequently been identified to transport water, and the group is referred to as the "Aquaporins". Aquaporin-4 (AQP4) is most abundant in the brain, which may be involved in CSF reabsorption and osmoregulation. However, ontogeny and regulatory mechanisms of AQP4 channels have not been reported. Northern blot analysis showed that AQP4 mRNA began to be expressed in the brain just before birth and that its expression gradually increased by PN7 and then decreased at adult level. AQP4 was expressed predominantly in the ependymal cells of ventricles in newborn rats. And then its expression decreased in ependymal cells and increased gradually in other regions including supraoptic and paraventricular nuclei. AQP4 is also expressed in the subfornical organ, in which the expression level is not changed after birth. Cryogenic brain injury did not affect expression of AQP4 mRNA, while ischemic brain injury decreased it. Osmotic water permeability of AQP4 channel expressed in Xenopus oocytes was inhibited by the pretreatment of BAPTA/AM and calmidazolium, a Ca2+/ Calmodulin kinase inhibitor, in a dose-dependent manner. These results indicate that the expression and the function of AQP4 channel are regulated by developmental processes and various pathophysiological conditions. These results will contribute to the understanding of fluid balance in the central nervous system and the osrmoregulatory mechanisms of the body.
Adult ; Animals ; Blotting, Northern ; Brain Injuries ; Brain* ; Calcium-Calmodulin-Dependent Protein Kinases ; Central Nervous System ; Diffusion ; Erythrocytes ; Humans ; Infant, Newborn ; Ischemia* ; Oocytes ; Osmoregulation ; Parturition ; Permeability ; Rats ; RNA, Messenger ; Subfornical Organ ; Water* ; Water-Electrolyte Balance ; Xenopus

PURPOSE: Antenatal steroid (AS) may result in lower insensible water loss (IWL), and higher urine output (UO) in early life. We examined if the postnatal fluid balance differed between infants exposed to AS or not (control) in VLBW infants. METHODS: Fifty-four VLBW infants were grouped into AS (n=24) or control (n=30). Fluid intake, UO, IWL and maximal % of weight loss on day 1, day 2, day 3 and day 7 after birth were analyzed. Daily maintenance fluid was determined in each infants by calculation of insensible water loss (IWL=[intake-output]-Delta wt) and UO. RESULTS: Fluid intake (AS vs control; 117.2+/-33.9 vs 126.0+/-29.6 mL/kg/d, P=0.315), IWL (28.1+/-23.7 vs 21.1+/-20.5 P=0.248), UO and maximal % of weight loss on day 7 were not different between groups: similar findings were observed on day 1, day 2, and day 3 after birth. Neonatal morbidities and clinical relevant factors were not different between groups. The duration of assisted ventilation was shorter in the AS than in the control (10.8+/-9.2 vs 27.6+/-26.2, P=0.002). However, the difference disappeared after adjustment for RDS severity and oxygenation index. CONCLUSION: VLBW infants exposed to AS did not have an alteration in postnatal fluid balance during the first week of life, when given fluid based on needs reflected by IWL and UO. The decreased need for assisted ventilation in the AS group may be related to the effects of steroid on fetal lung fluid absorption or maturity, but not on postnatal fluid balance.
Absorption ; Humans ; Infant* ; Infant, Very Low Birth Weight* ; Lung ; Oxygen ; Parturition ; Ventilation ; Water Loss, Insensible ; Water-Electrolyte Balance* ; Weight Loss

PURPOSE: Extremely-low-birth-weight infants (ELBWIs), especially those < or =24 gestational weeks (GW), presented extremes in IWL and changes of water balance. The purpose of the present study was to retrospectively investigate fluid and electrolyte balance in infants of < or =24-GW during the first postnatal week under high humidification. METHODS: Medical records of extremely-low-birth-weight infants (ELBWIs) who were born and admitted to the Neonatal Intensive Care Unit at Samsung Medical Center during March 2004-September 2010 were reviewed. Fluid intake, urine output, insensible water loss (IWL), and electrolyte balance of 22-GW (n=14), 23-GW (n=40), and 24-GW (n=67) infants nursed in high humidity (95%) were compared with > or =26-GW (n=65) infants nursed in 60% humidity. RESULTS: Survival rate until discharge was 33%, 82%, 75%, and 89.3% in 22-GW, 23-GW, 24-GW, and > or =26-GW infants, respectively. Fluid intake and IWL was higher in 22-GW and 23-WG, but not different in 24-GW, than in > or =26-GW infants. At postnatal days (P) 3-5, the urine output was significantly lower in > or =26-GW infants than in the other age groups. Serum sodium level was significantly higher in 22-, 23-, and 24-GW (P1-2) than in > or =26-GW infants. Hypernatremia (>150 mEq/dl sodium) was more frequent in 22-GW (71%), 23-GW (41%), and 24-GW (21%) than in > or =26-GW infants (14%). CONCLUSION: High-humidity environments significantly decreased fluid intake and improved electrolyte imbalance in 24-GW, but not 22- and 23-GW, infants. Increased IWL in the latter might be related to more immature skin, and implicates the need for additional nurturing conditions.
Apnea ; Electrolytes ; Humans ; Humidity ; Hypernatremia ; Infant ; Infant, Newborn ; Infant, Premature ; Intensive Care, Neonatal ; Medical Records ; Retrospective Studies ; Seizures ; Skin ; Sodium ; Survival Rate ; Water Loss, Insensible ; Water-Electrolyte Balance

PURPOSE: Extremely-low-birth-weight infants (ELBWIs), especially those < or =24 gestational weeks (GW), presented extremes in IWL and changes of water balance. The purpose of the present study was to retrospectively investigate fluid and electrolyte balance in infants of < or =24-GW during the first postnatal week under high humidification. METHODS: Medical records of extremely-low-birth-weight infants (ELBWIs) who were born and admitted to the Neonatal Intensive Care Unit at Samsung Medical Center during March 2004-September 2010 were reviewed. Fluid intake, urine output, insensible water loss (IWL) and electrolyte balance of 22-GW (n=14), 23-GW (n=40) and 24-GW (n=67) infants nursed in high humidity (95%) were compared with > or =26-GW (n=65) infants nursed in 60% humidity. RESULTS: Survival rate until discharge was 33%, 82%, 75% and 89.3% in 22-GW, 23-GW, 24-GW and > or =26-GW infants, respectively. Compared to > or =26-GW infants, fluid intake and IWL was higher in 22-GW and 23-WG, but not as different in 24-GW. At postnatal day (P) 3-5, urine output was significantly lower in > or =26-GW infants than in the other age groups. Serum sodium level was significantly higher in 22-, 23- and 24-GW (P1-2) than in > or =26-GW infants. Hypernatremia (>150 mEq/dl sodium) was more frequent in 22-GW (71%), 23-GW (41%) and 24-GW (21%) than in > or =26-GW infants (14%). CONCLUSION: High-humidity environments significantly decreased fluid intake and improved electrolyte imbalance in 24-GW, but not in 22- and 23-GW infants. Increased IWL in the latter might be related to more immature skin, implicating the need for additional nurturing conditions.
Electrolytes ; Humans ; Humidity ; Hypernatremia ; Infant ; Infant, Low Birth Weight ; Infant, Newborn ; Intensive Care, Neonatal ; Medical Records ; Retrospective Studies ; Skin ; Sodium ; Survival Rate ; Water Loss, Insensible ; Water-Electrolyte Balance

Hypodipsic hypernatremia is characterized by chronic or recurrent episodes of severe hypernatermia associated with dehydration and a lack of thirst. This constellation of deficits suggests that the syndrome is due to hypodipsia of destruction of the hypothalamic osmoreceptors that regulate thirst and ADH secretion. We report a child with abnormalities of the central nervous system who had hypernatremia and a lack of thirst without detectable abnormalities in the osmoregulation of ADH secretion. The patient was a 11 month old female and her chief complaints were poor oral intake and weight gain. There were recurrent hypernatremia with hyperosmosis and normal level of plasma ADH. With intravenous rehydratin, oral intake was improved and plasma sodium level decreased.
Central Nervous System ; Child ; Dehydration ; Female ; Humans ; Hypernatremia* ; Infant ; Osmoregulation ; Plasma ; Sodium ; Thirst ; Weight Gain

There appeared remarkably common disorder of water balance in psychiatric patients. Approximately 30% of the chronic inpatient population drinks fluids excessively, so called polydipsic, while 5% suffers episodes of water intoxication. Water intoxication is a serious problem characterized by profound hyponatremia and a diverse neurologic signs ranging from ataxia, confusion to death. The cause of polydipsia is even less clear. Although previous studies have suggested that it is related to cognitive dysfunction the possibility of an abnormality in the osmoregulation of thirst has not been investigated. But there is the hypothesis that polydipsic, hyponatremic schizophrenics exhibit increased neuroendocrine and behavioral sensitivity to dopamine in mesolimbic tracts, in proportion to the severity of their osmoregulatory disturbance. In order to provide the optimal clinical management of these common disturbances, the author will review their pathophysiology, assessment, treatment and relationship with mental illness.
Ataxia ; Dopamine ; Humans ; Hyponatremia ; Inpatients ; Neurologic Manifestations ; Osmoregulation ; Polydipsia* ; Psychotic Disorders ; Thirst ; Vasopressins* ; Water Intoxication*

Hypertonic or hypernatremic dehydration, which is uncommon in pediatric patients beyond infancy, has a distinct pathophysiology that differentiates the clinical presentation and management from other forms of dehydration. Severe hypernatremia may precipitate central nervous system injury, seizures, intracerebral bleeding, retardation, and even death. Causes of hypernatremia include inadequate water intake, salt overload, extrarenal water loss, defective osmoregulation, and water loss with simultaneous gain of solute. We experienced a case of hypernatremia due to esophageal foreign body. These authors reported a case with review of literatures.
Central Nervous System ; Dehydration ; Drinking ; Foreign Bodies* ; Hemorrhage ; Humans ; Hypernatremia* ; Osmoregulation ; Seizures

Previous studies by others have shown that administration of hypertonic saline (HS) induces c-fos expression in rat brain and old fibroblast cells are defective in transcription of c-fos in response to serum. The present immunohisto-chemical studies were undertaken to determine 1) the time that c-fos is expressed during the postnatal development of rat brain and 2) if there is aging-related change of c-fos expression in the osmoresponsive neurons after osmotic stimulus. Fos-like immunoreactivity (FLI) in response to HS treatment began to be detected dramatically at postnatal day (P) 14 in hypothalamic paraventricular nucleus (PVN), supraoptic nucleus (SON), and organum vasculosum lamina terminalis (OVLT). Intensity of FLI and number of Fos immunoreactive cells induced by HS were substantially reduced as rats age. Our data demonstrate for the first time that c-fos induction is decreased in aging-dependent manner and the time of c-fos induction during postnatal development is coincided with the status of differentiation in rat brain. We will interpret these findings in relation to synaptogenesis, and maturation or disability of signal transduction pathways in osmoresponsive neurons in rat brain.
Aging* ; Animals ; Brain ; Fibroblasts ; Hypothalamus ; Neurons* ; Osmoregulation* ; Paraventricular Hypothalamic Nucleus ; Rats* ; Signal Transduction ; Supraoptic Nucleus

In newborn infants with mechanical ventilation in the first few days of life, fluid balance must be closely monitored because inadequate therapy related to overload may result in serious complications such as patent ductus arteriosus and pulmonary edema. Very low birth weight infants have significant change in body water balance in early neonatal period secondary to a large insensible water loss (IWL) and immaturity of renal function. Consequently these infants tend to have a high incidence of fluid overload so that fluid restriction with high humidification is effective during especially the first week of life. In infants with bronchopulmonary dysplasia, diuretics such as furosemide may act directly to improve lung mechanics by reabsorption of lung fluid, but chronic use may cause electrolyte imbalance, nephrocalcinosis and hearing deficit. In the early phase of perinatal asphyxia with oliguria, fluid restriction to amount equal to urine output and IWL is critical in order to prevent volume excess and potassium should not be given to avoid hyperkalemia. Blood components should always be infused through transfusion set with standard filter. To minimize adverse reactions of transfusion, basic rules must be observed. Moreover, storage of blood cells in small aliquots, using leukocyte removal filters and irradiation of blood can be helpful to prevent multiple donor exposure, cytomegalovirus infection, alloimmunization, and graft-versus-host rejection.
Asphyxia ; Blood Cells ; Body Water ; Bronchopulmonary Dysplasia ; Cytomegalovirus Infections ; Diuretics ; Ductus Arteriosus, Patent ; Fluid Therapy* ; Furosemide ; Hearing ; Humans ; Hyperkalemia ; Incidence ; Infant ; Infant, Newborn ; Infant, Very Low Birth Weight ; Leukocytes ; Lung ; Mechanics ; Nephrocalcinosis ; Oliguria ; Potassium ; Pulmonary Edema ; Respiration, Artificial* ; Tissue Donors ; Water Loss, Insensible ; Water-Electrolyte Balance

No abstract available.
Acetylcysteine* ; Dermatitis, Atopic* ; Healthy Volunteers* ; Humans ; Skin* ; Water Loss, Insensible