Impaired social memories in 129P2 inbred mice are rescued by reduced Csk expression.

The C-terminal Src kinase (Csk) is an essential signaling factor guiding central nervous system (CNS) development. In the adult brain, Csk-mediated control of Src may also modulate glutamatergic synaptic transmission and N-methyl-d-aspartate receptor (NMDAR)-dependent synaptic plasticity. The regulation of N-methyl-d-aspartate (NMDA)-dependent plasticity by a myriad of kinase cascades has been investigated intensively during spatial and fear learning, while little is known about the regulatory kinases and role of NMDA-dependent plasticity during equally critical forms of social learning. We assessed social memory in Csk(+/+) and Csk(+/-) mice backcrossed onto 129P2, an inbred strain with wild-type impairments in social memory. Reduced Csk expression in Csk(+/-) mice was associated with increased NMDAR subunit 2B (NR2B) phosphorylation in the amygdala (AM) and olfactory bulb (OB), and with markedly improved social recognition memory and social transmission of food preference (STFP). In contrast, phosphorylation of NR2B was only slightly increased in the hippocampus of 129P2/Csk(+/-) mice, and the poor spatial object recognition memory of wild-type 129P2/Csk(+/+) mice was not rescued by reduced Csk expression. The Csk pathway appears to be a critical signaling cascade regulating social learning and memory, and presents a possible therapeutic target in diseases such as autism that are characterized by aberrant social behaviors.

Superior sagittal sinus thrombosis: a rare complication in a child with nephrotic syndrome.

A 2-year-old boy with new-onset nephrotic syndrome developed recurrent vomiting, apathy and papilloedema. Superior sagittal sinus thrombosis was diagnosed on cranial CT and MRI. He gradually recovered after treatment with heparin, fresh frozen plasma and warfarin with complete resolution of the thrombosis after 1 month. Superior sagittal sinus thrombosis is an extremely rare complication of nephrotic syndrome in children. Early diagnosis is essential for institution of anticoagulation therapy and a successful outcome.

Phenylketonuria screening: effect of early newborn discharge.

OBJECTIVE: To determine the percentage of term newborns discharged by 24 hours of life and the actions taken by physicians and institutions to avoid false-negative phenylketonuria (PKU) screens in these infants. DESIGN: Descriptive cross-sectional survey. PARTICIPANTS: One hundred forty term nurseries and 157 pediatricians. SELECTION PROCEDURE: Stratified sampling techniques were used to sample nurseries from the 1992 American Hospital Association guide to provide equal representation of each region of the country. Pediatricians were systematically sampled from a national list of practicing pediatricians supplied by Ross Laboratories to provide equal sampling from each state. RESULTS: The response rates were 95% (n = 133) for term nurseries and 83% (n = 131) for pediatricians. Twenty-four percent of healthy newborns are discharged by 24 hours of life. Ninety-three percent of nurseries screen all infants for PKU before discharge. In states without laws mandating rescreening, only 48% of institutions that discharge the majority of their infants (> 50%) by 24 hours of life rescreen. Also, in states without rescreening laws, 64% of pediatricians rescreen. The timing of this repeat screen ranges from less than 72 hours of life to 4 weeks. Determining which infants to rescreen varies by practitioner; some rescreen all infants, whereas others rescreen those discharged early. Just more than half of all pediatricians, whether practicing in a state requiring repeat PKU screening, claim to be familiar with the American Academy of Pediatrics recommendations regarding repeated PKU screening of infants discharged by 24 hours of life. CONCLUSION: Twenty-four percent of term newborns in the United States are discharged by 24 hours of life. Most hospitals screen all infants for PKU before discharge regardless of age. The majority of states do not mandate rescreening; rescreening policies among pediatricians and institutions in those states vary widely. A significant number of infants do not receive repeated screening and are therefore at risk for delayed or missed diagnosis of PKU because of insensitive initial screens. Pediatrician awareness of the need to perform repeated PKU screens on infants discharged by 24 hours is poor.

[Familial hemolytic uremic syndrome].

Hemolytic uremic syndrome (HUS) consists of an apparently heterogenous group of disorders resulting from a variety of diseases. Outcome and prognosis are largely determined by the basic disease. In the familial type there is frequently progressive deterioration and poor prognosis. The classic epidemic type usually has a better prognosis. The pathophysiology of familial HUS is unknown. Treatment includes transfusion of fresh frozen plasma or plasma exchanges. We report 2 siblings, male and female infants, who developed HUS at ages 7 and 8.5 months, respectively (but they were born 5 years apart). Their courses were characterized by slow onset, gradual deterioration, hypertension and fatal outcome in 1, and end-stage renal failure in the other.

Universal hepatitis B immunization.

OBJECTIVE: To determine the practices of US nurseries, neonatal intensive care units (NICUs), and pediatricians regarding universal hepatitis B vaccination. DESIGN: Descriptive cross-sectional survey. PARTICIPANTS: One hundred forty term nurseries, 152 NICUs, and 157 pediatricians. Selection procedure. Nurseries and NICUs were systematically sampled from the 1992 American Hospital Association Guide to provide equal sampling from each region of the country. Pediatricians were systematically sampled from a national list of practicing pediatricians supplied by Ross Laboratories to provide equal sampling from each state. RESULTS: The response rates were 95% (n = 133) for term nurseries, 95% (n = 144) for NICUs, and 83% (n = 131) for pediatricians. Sixty-two nurseries (47%) provide routine hepatitis B vaccine (HBV) to their infants. Eighty-five NICUs (59%) routinely vaccinate their preterm infants; 62 (73%) initiate the series just before discharge; and 11 (13%) do so at birth. Principal reasons for not vaccinating include cost and a preference to allow the primary-care physician to initiate the series. One hundred ten (85%) pediatricians provide universal hepatitis B vaccination. Principal reasons for not vaccinating include cost and parents opting against vaccination. CONCLUSIONS: More than half of NICUs provide HBV routinely to their preterm infants, predominantly just before hospital discharge. A minority of NICUs are initiating vaccination at birth, which may provide suboptimal seroconversion. Although less than half of participating term nurseries are routinely vaccinating before discharge, 85% of pediatricians do initiate HBV by two months of age. The principal reasons for not providing vaccine are financial.

Vesicoureteral reflux in boys: review of 196 cases.

To determine the frequency of vesicoureteral reflux (VUR) in boys, the authors retrospectively studied 724 boys who underwent voiding cystourethrography for the first time. VUR was identified in 196 of these patients (27.0%). Urinary tract infection was the indication for cystourethrography in 188 patients (25.9%), 80 of whom (42.5%) had VUR. Hypospadias was the second most frequent indication (179 patients [24.7%]), with VUR present in 32 (17.8%). A significant frequency of VUR was demonstrated in boys studied for various other conditions. Excretory urography in 588 boys revealed congenital anomalies of the upper urinary tract in 72, with VUR in 26 (36.1%), which was significantly higher than that in boys with hypospadias (P greater than .01). There was no significant difference between the frequency of VUR in boys with hypospadias with or without meatal stenosis (P greater than .9) and in boys with meatal stenosis with or without hypospadias (P greater than .9); thus, VUR seems to be independent of mild urethral obstruction and hypospadias. VUR was more frequent in boys with posterior urethral valves (62.5%, P less than .002). VUR in boys with urinary tract infection is as common as in girls. In most cases, its frequency in many apparently unrelated conditions is suggestive of its primary nature.

Vitamin D metabolism and expression in rats fed on low-calcium and low-phosphorus diets.

1. Cholecalciferol, radioactively labelled with both (14)C and (3)H, was administered weekly for 7 weeks to rats that had been depleted of vitamin D for 4 weeks before repletion with the radioactive vitamin. This permitted measurement of the steady-state effect on vitamin D metabolism of low-calcium and low-phosphorus regimens, as compared with a normal mineral intake. These dietary manoeuvres were carried out during the last 3 weeks of repletion. Cholecalciferol, 25-hydroxycholecalciferol and 1,25-dihydroxycholecalciferol were determined in plasma, intestine, kidney and bone. Ca(2+)-binding-protein content was measured in intestine and kidneys of comparable animals. 2. In rats on the low-calcium diets, 1,25-dihydroxycholecalciferol concentration was elevated in plasma, bone, kidney and intestine, and intestinal Ca(2+)-binding protein was increased to over twice the concentration found in the control animals. 3. The low-phosphorus regimens led to a decrease in plasma phosphate and 1,25-dihydroxycholecalciferol in all tissues studied, for the latter to the point where it was undetectable in plasma and bone. Intestinal and renal concentrations of Ca(2+)-binding protein were unchanged in the low-phosphate-intake group and decreased in the very-low-phosphate-intake group. 4. It is concluded that in the rat, unlike in the chick, hypophosphataemia is not associated with a stimulation of the production of 1,25-dihydroxycholecalciferol or its expression in the synthesis of Ca(2+)-binding protein. Therefore the plasma phosphate concentration does not appear to be directly involved in the regulation of the functional metabolism of vitamin D.