Organization and development of brain stem auditory nuclei in the chick: Ontogeny of postsynaptic responses

The onset of responsiveness to eighth nerve stimulation was examined in n. magnocellularis and n. laminaris, (second- and third-order neurons) of the chick brainstem auditory system. Extracellular microelectrode mapping techniques were used to examine postsynaptic responses in in vitro brainstem preparations. Two specific questions were addressed. First, what is the earliest time at which postsynaptic action potentials can be evoked in n. magnocellularis and n. laminaris by eighth nerve stimulation? Second, does responsiveness to eighth nerve stimulation develop along a spatial gradient in n. magnocellularis and, if so, how does this gradient compare with other developmental events observed in the chick auditory system? Postsynaptic responses in n. magnocellularis were first recorded at 11 days of incubation. Nucleus laminaris responses to direct stimulation of n. magnocellularis were also first recorded at 11 days, although n. laminaris responses to eighth nerve stimulation were not seen until 12 days of incubation. A gradient of response development within n. magnocellularis was indicated by mapping of responsive sites on days 11–13. At 11 days, responses to eighth nerve stimulation were restricted to the most anteromedial portion of n. magnocellularis. Between 11 and 13 days, cells in increasingly more posterolateral portions of n. magnocellularis became responsive. This is anteromedial-to-posterolateral gradient in n. magnocellularis is correlated with the basal-to-apical gradient of morphogenesis observed in the basilar papilla and morphogenetic gradients previously observed in n. magnocellularis and n. laminaris.     

Changes in water intake of Northumbrian adolescents 1980 to 2000

OBJECTIVES: To determine: total water intake in young English adolescents; the relative importance of sources of water intake; and changes in water intake and sources of water between 1980 and 2000. DESIGN: A cross-sectional observational study of the diets of 11-12-year-old children attending seven schools in south Northumberland, UK. The information obtained was compared with results from a similar survey carried out 20 years previously. METHODS: All children attending these schools were invited to participate. They completed a three-day diet diary with an interview on the fourth day, on two occasions during the school year. Standard UK food composition tables were used and water intake from various sources calculated. Anthropometric and social class information was obtained. RESULTS: Four hundred and twenty-four children completed all aspects of the study (64% of those eligible). The mean total water intake was 1,130 g d(-1), approximately the same as that recorded 20 years before. Water intake in relation to energy intake: water intake was 139 g MJ(-1) in boys and 143 g MJ(-1) in girls. Sixty-five per cent of water came from drinks and 35% from foods; very similar to proportions 20 years before. The sources of water in drinks had changed considerably, with a marked increase in consumption of soft drinks (especially carbonated drinks) and a decrease in consumption of hot drinks and milk. There were a few differences between sexes but little difference between social groups. CONCLUSIONS: Total water intake was similar to that recorded 20 years previously and lower than intakes reported in other countries. Changes in the sources of water meant that less water consumed was likely to come from the tap in the house and more from drinks made elsewhere, than 20 years previously. These changes have implications for estimating fluoride intake in fluoridated areas.     

Monozygotic pregnancies from transfers of zona-free blastocysts

To minimize the risk of identical twinning the zona pellucida (ZP) was completely removed before blastocyst ET in all blastocyst transfers performed between May 1, 1999 and April 30, 2000. Compared to prior, zona intact, blastocyst transfers carried over between September 1, 1998 and April 30, 1999 no significant difference was noted regarding implantation, pregnancy, monozygotic pregnancy, or multiple gestation rates, thereby indicating that monozygosity can arise independently of the ZP.     

A pilot study of newer antidepressant concentrations in cord and maternal serum and possible effects in the neonate

Antidepressants are often used antenatally, and placental transfer may lead to adverse effects (toxicity) in the neonate. Pregnant women taking fluoxetine (n=4), sertraline (n=4), paroxetine (n=2) or venlafaxine (n=1) in the last trimester were studied. Maternal and cord sera were collected at delivery and infant serum on day 5 after birth for measurement of antidepressant concentrations. Neonatal Abstinence Scores (NAS) were measured in the infants on days 13 after birth. In maternal serum, median drug concentrations were: fluoxetine (96 microg/l), norfluoxetine (110 microg/l), sertraline (11 microg/l), desmethylsertraline (38 microg/l), paroxetine (mean 12 microg/l), venlafaxine (220 microg/l), and O-desmethylvenlafaxine (392 microg/l). Corresponding median values in cord serum were: fluoxetine (65 microg/l), norfluoxetine (81 microg/l), sertraline (10 microg/l), desmethylsertraline (27 microg/l), paroxetine (mean 6 microg/l), venlafaxine (232 microg/l), and O-desmethylvenlafaxine (406 microg/l). Corresponding median cord:maternal concentration ratios were 0.67 for fluoxetine and 0.72 for norfluoxetine, 0.67 for sertraline and 0.63 for demethylsertraline, 0.52 (mean) for paroxetine, and 1.1 and 1.0 for venlafaxine and O-desmethylvenlafaxine respectively. The neonates of two patients taking fluoxetine had high NAS. Only fluoxetine and norfluoxetine were detected in infant serum. Our data show substantial placental transfer of antidepressants, but only fluoxetine persisted in the infants serum. Neonatal toxicity may be associated with serotonin uptake blockade, and also be influenced by neonatal clearance.     

Motor co-ordination in a South Indian population of children

AIMS: To examine the associations of motor co-ordination in Kerala, South India. METHODS: The Modified Oseretsky Test of motor co-ordination was administered to 1155 representative children during a door-to-door survey of 8-12 year olds. Reading, vocabulary and visuospatial reasoning were measured, as were height and weight. Information on medical history, socio-demographic background and behaviour was systematically collected. RESULTS: Age was the major association of motor incoordination indicating the importance of maturation. Behaviour, vocabulary, visuospatial reasoning, material deprivation, perinatal complications, chronic physical symptoms and occupational status of the father were also independently associated with motor co-ordination. Using sibling pairs, evidence of familial aggregation of motor co-ordination was found.