Oxytocin Modulates Expression of Neuron and Glial Markers in the Rat Hippocampus.

Neuropeptides including oxytocin belong to the group of factors that may play a role in the control of neuronal cell survival, proliferation and differentiation. The aim of the present study was to investigate potential contribution of oxytocin to neuronal differentiation by measuring gene and protein expression of specific neuron and glial markers in the brain. Neonatal and adult oxytocin administration was used to reveal developmental and/or acute effects of oxytocin in Wistar rats. Gene and protein expression of neuron-specific enolase (NSE) in the hippocampus was increased in 21-day and 2-month old rats in response to neonatal oxytocin administration. Neonatal oxytocin treatment induced a significant increase of gene and protein expression of the marker of astrocytes - glial fibrillary acid protein (GFAP). Oxytocin treatment resulted in a decrease of oligodendrocyte marker mRNA - 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) - in 21-day and 2-month old rats, while no change of CD68 mRNA, marker of microglia, was observed. Central oxytocin administration in adult rats induced a significant increase of gene expression of NSE and CNPase. The present study provides the first data revealing the effect of oxytocin on the expression of neuron and glial markers in the brain. It may be suggested that the oxytocin system is involved in the regulation of development of neuronal precursor cells in the brain.

Prolactin increases expression of cytoskeletal proteins in SK-N-SH cells.

Although many studies have demonstrated the role of prolactin in the central nervous system, there is a considerable lack of known effects of prolactin on the parameters of neurogenesis and neuronal differentiation. The aim of the present study was to test whether prolactin changes gene expression and protein levels of nestin and microtubule-associated protein 2 (MAP2) in neuroblastoma (SK-N-SH) and glioblastoma (U-87MG) cells. Nestin and MAP2 represent cytoskeletal proteins associated with neuronal differentiation and they contribute to radial growth of the axons, dendrites and glial processes. SK-N-SH and U-87MG cells were exposed to prolactin (10 nM) for 48 h. Total mRNA was extracted. After reverse transcription, qPCR with specific primers for nestin and MAP2 was performed. The levels of proteins were measured by the In-Cell Western assay. Mitochondrial activity test was used to evaluate the viability of cells under the influence of prolactin. Incubation with 10 nM prolactin did not change the viability, either in SK-N-SH or in U-87MG cells. Prolactin significantly increased the gene expression and protein levels of both nestin and MAP2 in SK-N-SH cells, while no significant changes were observed in U-87MG cells. The presented data suggest that prolactin is linked to the regulation of cytoskeletal proteins in the neuronal type of cells and might be important for their differentiation.

Oxytocin action on components of endoplasmic reticulum in hippocampal neuronal cells.

Despite the known importance of the endoplasmic reticulum (ER) in protein synthesis and vesicular transport, it is not clear whether neuropeptide and neuromodulator oxytocin can directly affect components of the ER in neuronal cells. Therefore, in the present study, we hypothesize that incubation of hippocampal neuronal cells in a presence of oxytocin 1) plays a role in the regulation of the expression of selected ER chaperone components and molecules involved in unfolded protein response pathway 2) affects distribution of the intracellular fluorescence signal highly selective for the ER. We found that oxytocin (1 µM) after 60 min significantly decreased the gene expression of oxidoreductase Ero1ß, chaperone glucose-regulated proteins (Grp) 78 and Grp94. A significant decrease in GRP78 protein levels in response to oxytocin treatment occurred after 30, 60 and 120 min. We also observed a time-dependent increase in calreticulin protein levels with a statistically significant increase observed after 360 min. We found that the dynamics of the ER network changes significantly within 2 h of incubation under the influence of oxytocin. In conclusion we have shown that ER chaperones, oxidoreductases and trafficking molecules in neuronal cells are changing in response to oxytocin treatment in a short-term scenario potentially relevant for growth of dendrites and axons.

Hypoglycemia screening of asymptomatic newborns on the 2nd day of life.

BACKGROUND: Neonatal hypoglycemia management in the first 48 hours is guided by the American Academy of Pediatrics (AAP) and Pediatric Endocrine Society (PES) recommendations. Our aim was to determine the incidence of hypoglycemia via point of care test (POCT) on the 2nd day of life (DOL) among healthy, asymptomatic neonates regardless of risk factors. METHODS: In this prospective observational study, preprandial point of care glucose concentration was measured on the 2nd DOL in 150 healthy, asymptomatic neonates in the newborn nursery. We used 50 mg/dl (2.8 mmol/L) as the hypoglycemia threshold based on PES recommendations. RESULTS: The incidence of hypoglycemia on the second DOL was 10% among asymptomatic neonates (no risk factors = 8%; late preterm birth (LPT) + small for gestational age (SGA) = 16%; large for gestational age (LGA) + infant of diabetic mother (IDM) = 6%). SGA + LPT neonates accounted for the majority of the hypoglycemic cases (53.3%) and exhibited a trend towards the lowest glucose concentration (p = 0.09). CONCLUSION: The incidence of hypoglycemia on DOL 2 among asymptomatic neonates is high and of unclear significance in the absence of dedicated neurodevelopmental follow-up.

Nasal continuous positive airway pressure affects pre- and postprandial intestinal blood flow velocity in preterm infants.

OBJECTIVE: To measure the effect of nasal continuous positive airway pressure (CPAP) on intestinal blood flow velocity responses to enteral feedings and left ventricular output (LVO). STUDY DESIGN: Eighteen infants completed the study (birth weight 1793+/-350 g, gestational age 32.1+/-1.1 weeks). On the day infants were weaned from CPAP to room air, pre- and postprandial (0, 30, 60 and 90 min after feeding) mean velocity (MV), peak systolic velocity (PSV) and end diastolic velocity (EDV) were measured for one feeding given when receiving CPAP ('on CPAP'), and for one feeding given after CPAP had been discontinued ('off CPAP'). Preprandial LVO was measured before and after CPAP discontinuation. RESULT: MV and PSV were significantly lower when infants were on CPAP (P<0.05). Maximum postprandial MV, PSV and EDV occurred at 30 min when on CPAP and at 60 min when off CPAP. Preprandial LVO was similar when infants were on and off CPAP. CONCLUSION: CPAP administration affects pre- and postprandial intestinal blood flow velocity, which may impact tolerance to enteral feedings.

Umbilical artery catheters do not affect intestinal blood flow responses to minimal enteral feedings.

OBJECTIVE: To investigate the effects of umbilical artery catheters (UACs) on superior mesenteric artery (SMA) blood flow velocity (BFV) following enteral feedings in very low birth weight preterm infants. STUDY DESIGN: Very low birth weight preterm infants who had UACs inserted as part of standard clinical care were enrolled in this prospective study. On the day the UAC was scheduled to be removed, pre- and postprandial SMA BFV (mean, peak systolic and end diastolic velocities) were measured in conjunction with a minimal enteral feeding given while the UAC was in place. The same measurements were made with the next feeding given after the UAC was removed. Preprandial measurements were made at least 3 h after the last enteral feeding, and postprandial measurements were made 30, 45 and 60 min after the feeding began. The same volume and type of feeding were used for both studies. RESULTS: The birth weight and gestational age of the 19 infants who completed the study were 1014+/-221 g and 27.4+/-1.9 weeks, respectively. Infants were 4.6+/-1.7-days-old when the first SMA BFV measurement was made, the volume of enteral feedings was 1.3+/-0.6 ml, and the time between the two enteral feedings was 4.7+/-3.2 h. Preprandial SMA BFV did not differ with the UAC in place compared with the UAC removed. Peak postprandial velocities were at 45 min after feedings began. The percent increase from baseline was not significantly different with the UAC in place compared with the UAC removed. CONCLUSIONS: Preprandial SMA BFV and postprandial SMA BFV responses to minimal enteral feedings were not affected by the presence of a UAC.

Early feeding tolerance in small for gestational age infants with normal versus abnormal antenatal Doppler characteristics.

OBJECTIVES: To determine differences in feeding tolerance amongst preterm small for gestational age (SGA) infants with normal versus abnormal umbilical artery Doppler flow defined as absent or reversed end diastolic flow (AREDF). METHODS: This was a retrospective cohort study of infants <35 weeks gestational age (GA) and birth weight (BW) <10th percentile. Day of initiation of feeds, days to full feeds and CRIB II scores were the primary outcomes. Clinical characteristics were compared between the groups of SGA infants with normal and AREDF. Multivariable regression models were fit to the data to adjust for potential confounders of the association of AREDF and feeding intolerance. RESULTS: 120 infants with normal and 64 infants with AREDF were included. The infants with AREDF were smaller (971 g vs. 1183 g, p = 0.0002), less mature (29.9 wks vs. 31.2 wks, p = 0.0009), had higher CRIB II score (7.2 vs. 5.2, p = 0.0033), started feeding later (4.1 days vs. 3.3 days, p = 0.020) and advanced slower to full feeds (17.7 days vs. 13.7 days, p = 0.0017). Necrotizing enterocolitis was similar between the groups (p = 0.18). After adjusting for confounders, Doppler flow was no longer a significant predictor of the initiation (p = 0.37) and advancement of feeds (p = 0.44). CONCLUSIONS: Infants with AREDF are sicker at birth and have more feeding difficulties; after adjusting for BW and GA, Doppler flow was no longer a significant predictor of feeding intolerance.

Factors that influence mesenteric artery blood flow velocity in newborn preterm infants.

OBJECTIVES: To identify demographic and clinical variables that relate to the postnatal increase in intestinal blood flow velocity in preterm infants. STUDY DESIGN: Fasting or preprandial peak systolic velocity (PSV) and time-averaged mean velocity (TAMV) in the superior mesenteric artery were measured once each day for the first 5 days of life. We investigated the relationship between blood flow velocity and the following variables: birth weight, gestational age, feeding volumes, number of days to reach full feeding volumes, type of feeding given, continuous positive airway pressure (CPAP) administration and hyperalimentation (HAL) administration. RESULTS: Twenty-five infants with a mean birth weight of 1740 g and mean gestational age of 31.8 weeks were studied. There were significant increases in PSV (P < 0.001) and TAMV (P = 0.005) from postnatal day 1 to 5. The postnatal increase in TAMV and PSV was attenuated in infants administered CPAP or HAL for > or =3 days; the results remained significant after controlling for birth weight and gestational age. There was a significant correlation (P < 0.02) between volume of enteral feedings given on 2 of 5 days for TAMV, and on 1 of 5 days for PSV. CONCLUSIONS: These data support previous findings of significant increases in intestinal blood flow in preterm infants during the first week of life, and of inconsistent effects of enteral feeding volumes on fasting or preprandial intestinal blood flow. The reasons for, and the clinical implications of, attenuated increases in postnatal intestinal blood flow in infants on CPAP or HAL require further investigation.

Oxytocin Increases Neurite Length and Expression of Cytoskeletal Proteins Associated with Neuronal Growth.

Neuropeptide oxytocin acts as a growth and differentiation factor; however, its effects on neurite growth are poorly understood. The aims of the present study were (1) to evaluate time effects of oxytocin on expression of nestin and MAP2; (2) to measure the effect of oxytocin on gene expression of ß-actin, vimentin, cofilin, and drebrin; and (3) to measure changes in neurite length and number in response to oxytocin/oxytocin receptor antagonist L-371,257. Exposure of SH-SY5Y cells to 1 µM oxytocin resulted in a significant increase in gene expression and protein levels of nestin after 12, 24, and 48 h. Oxytocin treatment induced no changes in gene expression of MAP2; however, a decrease of protein levels was observed in all time intervals. Gene expression of ß-actin, vimentin, and drebrin increased in response to oxytocin. Oxytocin induced significant elongation of neurites after 12, 24, and 48 h. No change in neurite length was observed in the presence of the combination of retinoic acid and oxytocin receptor antagonist L-371,257. Oxytocin treatment for 12 h increased the number of neurites. Overall, the present data suggest that oxytocin contributes to the regulation of expression of cytoskeletal proteins associated with growth of neuronal cones and induces neurite elongation mediated by oxytocin receptors at least in certain types of neuronal cells.

Bone isoenzyme of serum alkaline phosphatase in acromegaly.

In 37 patients with active acromegaly and in 15 patients with inactive acromegaly, activity of bone isoenzyme of serum alkaline phosphatase correlated (P less than 0.001) with serum concentration of immunoreactive growth hormone. By using stepwise regression analysis, the predication of serum growth hormone values based on serum levels of bone isoenzyme of serum alkaline phosphatase, gamma-glutamyl transferase and calcium in these patients with acromegaly was within 1 S.D. range in 37 patients and in only 2 patients was it out of 2 S.D. range. By using discriminant analysis, based on bone and liver isoenzymes of serum alaline phosphatase and urinary hydroxyproline excretion, 87%, 60% and 97% of the classification of patients with active and inactive acromegaly and healthy adults, respectively, was correct. The multivariate approach offers a quantitative appraisal of the biochemical parameters of peripheral growth hormone action used as an indicator of growth hormone concentration in patients with acromegaly.

Bone isoenzyme of serum alkaline phosphatase in diabetes mellitus.

Increased activity of bone isoenzyme of serum alkaline phosphatase was found in 52, 82 and 72% of the patients on dietary, oral agents, and insulin regimens, respectively. Significant positive correlations between the activity of bone isoenzyme and urinary hydroxyproline excretion in diabetes are similar to those found in osteoporosis. In stepwise regression analysis, negative correlations were found between the parameters of turnover of bone organic matrix and serum calcium levels; the influence of blood glucose levels in the expression of the biochemical parameters of bone metabolism was most pronounced in patients on oral agents. The results explain moderate hyperphosphatasia, known in diabetes, and support a metabolic etiology for the bone disease in diabetes mellitus.

Age and sex dependency of the biochemical indices of bone remodelling.

The values for the bone isoenzyme of serum alkaline phosphatase peak in the first two years of age, between 6 and 7 years of age, before the end of puberty and in the postmenopause. A population between the ages of 29 and 45 provides a reference population to which all other age groupings can be compared. A significant positive correlation was found between bone isoenzyme of serum alkaline phosphatase and urinary hydroxyproline excretion in children as well as after puberty. However, in the children the urinary hydroxyproline excretion was significantly higher when compared with the bone isoenzyme of alkaline phosphatase. A significant positive correlation was found between the bone isoenzyme of alkaline phosphatase and plasma tartrate-resistant acid phosphatase, irrespective of age and sex. The biochemical indices of bone remodelling correlated significantly with the growth rate in children and adolescents. The results are in good agreement with the concept of the coupling of bone formation to bone resorption.

Relationship of plasma tartrate resistant acid phosphatase to the bone isoenzyme of serum alkaline phosphatase in hyperparathyroidism.

In 46 patients with primary hyperparathyroidism, in 21 non-dialysed patients with advanced renal failure, and in 52 patients on hemodialysis, a significant positive correlation was found between bone isoenzyme of serum alkaline phosphatase and plasma tartrate resistant acid phosphatase. In primary hyperparathyroidism, a significant positive correlation was found between the radiological degree of osteodystrophy and the biochemical parameters of bone remodelling. After removal of the parathyroid adenoma, only the tartrate-resistant acid phosphatase decreased to normal limits. Plasma tartrate resistant acid phosphatase was most significantly influenced by serum immunoreactive parathyroid hormone levels. In chronic renal failure, bone isoenzyme of serum alkaline phosphatase was most significantly influenced by serum immunoreactive parathyroid hormone levels, by hypocalcemia and by duration of hemodialysis. The results confirm that in hyperparathyroidism the extent of the whole-body rates of bone resorption and formation are approximately equal. The biochemical parameters can be used for serial assessment of the course of the disease but are not specific for diagnosis.

Sequential dependences of perceptual interpretations of a repetitively illuminated reversible figure.

The Necker cube pattern was illuminated by xenon flashes repetitively at different but always regular interstimulus intervals. Subjects pushed one of two buttons corresponding to the subjective perceptual interpretation of the pattern. Analysis of the resulting binary sequences showed that none of the sequences was random. The order of Markovian dependence was higher for sequences with longer (3.6 and 2.4 s) interstimulus intervals than for shorter (1.2 s) ones. This result points to the significance of perceptual sets related to short-term memory mechanism upon perception.

Probiotics supplementation increases intestinal blood flow velocity in extremely low birth weight preterm infants.

OBJECTIVE: To determine whether probiotics supplementation affects intestinal blood flow velocity in extremely low birth weight neonates. STUDY DESIGN: In this randomized, double-blind, placebo-controlled study, probiotics were added to the first enteral feeding and continued until discharge or 34 weeks postmenstrual age. Pulsed Doppler was used to measure preprandial and postprandial (at 30 and 60 min) time-averaged mean velocity (TAMV), peak systolic velocity (PSV) and end diastolic velocity (EDV) during the second week of life after ≥ 7 days of probiotics supplementation. RESULT: A total of 31 infants were studied, 15 were randomized to the probiotic and 16 to the placebo groups. There was a significant postprandial increase in TAMV for the probiotic vs the placebo group (P=0.035), with PSV and EDV showing a trend. Demographic and clinical variables were similar between the groups. CONCLUSION: Probiotics administration significantly increases postprandial intestinal blood flow in extremely low birth weight preterm neonates when compared with the placebo group.

[Mechanisms of growth of neuronal axons and dendrites]. / Mechanizmy zmien dlzky axónov a dendritov neurónu.

Brain development is determined by neuronal differentiation including changes of cell polarity and asymetric growth of neuronal processes. Although, there are many unkown factors contributing to changes of lenght of neuronal cones, mounting experimental and review papers focus on changes of growth conus and role of axonal transport. In particular, mechanisms of actin/microtubule polymerisation and depolymerisation are important. Role of intracellular calcium is also significant. Normal and properly timed changes of lenght of axons and dendrites are dependent on interaction of neurons and glia. Moreover, regeneration of injured axons is dependent on growth factors secreted from glial cells. The aim of the present study is characterisation of the most important mechanisms underlying changes of lenght of neurites.