Hyperphagia in neonates withdrawing from methadone.
(9/4202)
AIMS: To examine whether hyperphagia is a clinically significant problem in infants born to women receiving methadone maintenance. METHODS: The volume of feeds, changes in infant body weight, as well as occurrence of adverse clinical effects in infants withdrawing from methadone were studied during the first month of life. A retrospective chart review was conducted for all infants at San Francisco General between 1992 and 1995, born to women receiving methadone maintenance during their pregnancy. Forty four infants were identified and the data obtained from hospital medical records. The daily oral intake of these infants was recorded during the first month of life. The incidence of hyperphagia (oral intake > 190 cc/kg/day) was measured. Associations between infant oral intake and maternal methadone dose were studied using correlation analysis as well as Anova for repeated measures. Adverse clinical symptoms were also recorded. A subset of premature infants was studied separately. RESULTS: The incidence of hyperphagia was 26% by day 8 and 56% by day 16 of life in the infants. Hyperphagia was not associated with maternal methadone dose or with infant withdrawal scores. Infants who were hyperphagic lost significantly more weight during the first week of life than those who were not. Despite significantly greater intake, the hyperphagic infants did not gain weight more rapidly during the first month of life compared with those infants with lower oral intake. Infants who were hyperphagic (maximum intake of 290 cc/kg/day) did not experience increased vomiting, aspiration, diarrhoea, or abdominal distention. CONCLUSIONS: Hyperphagia is commonly found in infants withdrawing from methadone and can be persistent in a significant number. Hyperphagia was not associated with either increased neonatal weight gain or with adverse gastrointestinal consequences. Hyperphagia may occur in infants withdrawing from methadone who have high metabolic demands due to clinical signs not controlled by opiate treatment. (+info)
Effect of multiple courses of antenatal corticosteroids on pituitary-adrenal function in preterm infants.
(10/4202)
AIM: To evaluate the pituitary-adrenal function of preterm infants whose mothers received multiple courses (8 or more doses) of antenatal dexamethasone. METHODS: The pituitary-adrenal function of 14 preterm infants whose mothers received eight or more doses of antenatal dexamethasone were assessed using the human corticotrophin releasing hormone (hCRH) stimulation test when 7 days (n = 14) and 14 days old (n = 12). During each test, blood samples were taken at 0 (baseline), 15, 30 and 60 minutes after an intravenous bolus dose of hCRH (1 microg/kg). The corresponding hormone concentrations were compared between days 7 and 14, and with various associated factors. RESULTS: The baseline (0 min) plasma adrenocorticotrophic hormone concentration was significantly higher at day 14 than at day 7 (p = 0.036). None of the corresponding poststimulation (15, 30, and 60 min) hormone concentrations was significantly different between the two time epochs. When the association between the hormone concentrations and the number of antenatal dexamethasone doses received by the mothers was assessed, a significant negative correlation was observed in serum cortisol concentrations at 15 and 30 min on day 14 (r = -0.59, p = 0.04 and r = -0.60, p = 0.039, respectively). CONCLUSIONS: The absence of a significant difference in poststimulation hormone concentrations between days 7 and 14 in this cohort of infants, and the similarity of their hormone responses with those of older children and adults, suggests that no severe pituitary-adrenal suppression had occurred. None the less there was evidence of mild adrenal suppression in some of the treated infants. Vigilance in monitoring blood pressure, electrolytes and signs of adrenal suppression in infants whose mothers receive multiple courses (8 or more doses) of antenatal dexamethasone is required, as some of them might have diminished adrenal reserve. (+info)
Catecholamine synthesis is mediated by tyrosinase in the absence of tyrosine hydroxylase.
(11/4202)
Catecholamine neurotransmitters are synthesized by hydroxylation of tyrosine to L-dihydroxyphenylalanine (L-Dopa) by tyrosine hydroxylase (TH). The elimination of TH in both pigmented and albino mice described here, like pigmented TH-null mice reported previously (Kobayashi et al., 1995; Zhou et al., 1995), demonstrates the unequivocal requirement for catecholamines during embryonic development. Although the lack of TH is fatal, TH-null embryos can be rescued by administration of catecholamine precursors to pregnant dams. Once born, TH-null pups can survive without further treatment until weaning. Given the relatively rapid half-life of catecholamines, we expected to find none in postnatal TH-null pups. Despite the fact that the TH-null pups lack TH and have not been supplemented with catecholamine precursers, catecholamines are readily detected in our pigmented line of TH-null mice by glyoxylic acid-induced histofluorescence at postnatal day 7 (P7) and P15 and quantitatively at P15 in sympathetically innervated peripheral organs, in sympathetic ganglia, in adrenal glands, and in brains. Between 2 and 22% of wild-type catecholamine concentrations are found in these tissues in mutant pigmented mice. To ascertain the source of the catecholamine, we examined postnatal TH-null albino mice that lack tyrosinase, another enzyme that converts tyrosine to L-Dopa but does so during melanin synthesis. In contrast to the pigmented TH-null mice, catecholamine histofluorescence is undetectable in postnatal albino mutants, and the catecholamine content of TH-null pups lacking tyrosinase is 18% or less than that of TH-null mice with tyrosinase. Thus, these extraordinary circumstances reveal that tyrosinase serves as an alternative pathway to supply catecholamines. (+info)
Maternal hypothyroxinemia disrupts neurotransmitter metabolic enzymes in developing brain.
(12/4202)
Maternal thyroid status influences early brain development and, consequently, cognitive and motor function in humans and rats. The biochemical targets of maternal thyroid hormone (TH) action in fetal brain remain poorly defined. A partially thyroidectomized rat dam model was therefore used to investigate the influence of maternal hypothyroxinemia on the specific activities of cholinergic and monoaminergic neurotransmitter metabolic enzymes in the developing brain. Maternal hypothyroxinemia was associated with reduced monoamine oxidase (MAO) activity in fetal whole brain at 16 and 19 days gestation (dg). A similar trend was observed for choline acetyltransferase (ChAT) activity. In contrast, DOPA decarboxylase (DDC) activity was markedly elevated at 21 dg. Further study of these enzymes at 14 dg showed no differences between normal and experimental progeny - suggesting they become TH sensitive after this age. Tyrosine hydroxylase (TyrH) and acetylcholinesterase (AChE) activities were unaffected prenatally. During postnatal development, the activities of TyrH, MAO, DDC and, to a lesser extent, AChE were increased in a brain region- and age-specific manner in experimental progeny. The prenatal disturbances noted in this study may have wide-ranging consequences since they occur when neurotransmitters have putative neurotropic roles in brain development. Furthermore, the chronic disturbances in enzyme activity observed during postnatal life may affect neurotransmission, thereby contributing to the behavioural dysfunction seen in adult progeny of hypothyroxinemic dams. (+info)
Lack of developmental neurotoxicity of MN rgp 120/HIV-1 administered subcutaneously to neonatal rats.
(13/4202)
The potential for neurotoxic effects was evaluated in rat off-spring after exposure in utero and/or during the neonatal period to a recombinant subunit vaccine of gp120 prepared from the MN strain of HIV-1 (MN rgp 120/HIV-1). Thirty pregnant female rats were given MN rgp120/HIV-1 with alum adjuvant, and 30 rats were given vehicle, once every 3 days from Day 1 of presumed gestation until parturition. One pup/sex/litter from treated and control group dams were given a daily subcutaneous injection, from Day 1 through Day 22 postpartum (PP) of vehicle, MN rgp120/HIV-1, MN rgp120/HIV-1 with alum, or MN rgp120/HIV-1 with QS-21 adjuvant. Neurobehavioral and physical development were evaluated (preweaning reflex and development, sexual maturation, motor activity, acoustic startle, passive avoidance, functional observational battery, and water M-maze testing), and tissues were processed for anatomical examination (whole and regional brain weights, and neuropathology). Administration of MN rgp120/HIV-1, with or without adjuvant, to pups did not cause any persistent effect on any parameter evaluated. Neurohistological examination did not reveal any pathological effects related to treatment. Thus, MN rgp120/HIV-1 alone or formulated as a vaccine does not cause neurotoxicity or developmental toxicity in neonatal rats after exposure in utero and/or during the neonatal period. (+info)
Influence of parental smoking on respiratory symptoms during the first decade of life: the Tucson Children's Respiratory Study.
(14/4202)
Compelling evidence suggests a causal relation between exposure to parental cigarette smoking and respiratory symptoms during childhood. Still, the roles of prenatal versus postnatal parental smoking need clarification. In this study, the authors assessed the effects of passive smoking on respiratory symptoms in a cohort of over 1,000 children born during 1980-1984. The children were enrolled in the Tucson Children's Respiratory Study in Tucson, Arizona, and were followed from birth to age 11 years. The population was generally middle class and consisted of two main ethnic groups, non-Hispanic Whites (75%) and Hispanics (20%), reflecting Tucson's population. Information on parental smoking and on wheeze and cough in their children was elicited from parents by using questionnaires at five different surveys. Data were analyzed both cross-sectionally and by using the generalized estimation equation approach, a longitudinal mixed-effects model. The best-fitting model indicated that maternal prenatal but not postnatal smoking was associated with current wheeze (odds ratio = 2.3, 95% confidence interval 1.4-3.8) independently of a family history of asthma, socioeconomic factors, and birth weight. This effect was time dependent and significant only below age 3 years; although independent of gender, the association was stronger for girls (odds ratio = 3.6, 95% confidence interval 1.6-8.0). Cough was not associated with parental smoking during the first decade of life. This transitory effect of maternal prenatal smoking on wheezing could be due to changes that affect the early stages of lung development. (+info)
Effect of in-utero diethylstilboestrol exposure on human oocyte quality and fertilization in a programme of in-vitro fertilization.
(15/4202)
Genital tract abnormalities and adverse pregnancy outcome are well known in women exposed in utero to diethylstilboestrol (DES). Data about adverse reproductive performance in women exposed to DES have been published, including controversial reports of menstrual dysfunction, poor responses after ovarian stimulation, oocyte maturation and fertilization abnormalities. We compared oocyte quality, in-vitro fertilization results and embryo quality for women exposed in utero to DES with a control group. Between 1989 and 1996, 56 DES-exposed women who had 125 in-vitro fertilization (IVF) attempts were retrospectively compared to a control group of 45 women with tubal disease, who underwent 73 IVF attempts. Couples suffering from male infertility were excluded. The parameters compared were oocyte quality (maturation abnormalities, immature oocyte, mature oocyte), fertilization and cleavage rate (per treated and metaphase II oocytes), and embryo quality (number and grade). We found no significant difference in oocyte maturational status, fertilization rates, cleavage rates, embryo quality and development between DES-exposed subjects and control subjects. These results suggest that in-utero exposure to DES has no significant influence on oocyte quality and fertilization ability as judged during IVF attempts. (+info)
Altered cardiovascular haemodynamics and baroreceptor-heart rate reflex in adult sheep after prenatal exposure to dexamethasone.
(16/4202)
Numerous epidemiological studies, together with mounting evidence from studies in animals, point to a correlation between an adverse intrauterine environment and the early onset of cardiovascular and metabolic diseases later in life. We were the first to show that sheep exposed to dexamethasone (0.28 mg.kg-1.day-1 for only 2 days) at the end of the first month of pregnancy (PTG1), but not those exposed at the end of the second month of pregnancy (PTG2), had a higher basal mean arterial pressure (MAP) 19 months after birth. In the present study we report the MAP, cardiovascular haemodynamics and baroreflex sensitivity in these animals at 40 months of age. MAP in the PTG1 group was significantly higher than in the control group (91+/-1 mmHg and 81+/-1 mmHg respectively; P<0.001) and also when compared with the PTG2 group (82+/-1 mmHg; P<0.001). There was a significant increase in cardiac output in the PTG1 group compared with the control group (108+/-2 and 96+/-4 ml.min-1.kg-1 respectively; P<0.05). The increase in cardiac output in the PTG1 group was due to an increase in stroke volume (1.82+/-0.08 ml.kg-1. beat-1, compared with 1.46+/-0.06 ml.kg-1.beat-1 in the control group; P<0.05), but not in heart rate. In the hypertensive group of animals (PTG1), there was a rightward shift of the baroreflex curve. In group PTG2 (the normotensive group of animals), a lower gain was found before and during propranolol treatment. The decrease in gain of the baroreflex was not associated with changes in heart rate range, suggesting an impairment in the central processing of the baroreceptor signals. Thus sheep fetuses exposed to dexamethasone for only 2 days at the end of the first month of gestation have high blood pressure (dependent upon the increase in cardiac output) and a reset of the baroreflex at 40 months of age. Animals that have received prenatal dexamethasone closer to mid-gestation, although normotensive with normal cardiac output, showed an altered baroreceptor-heart rate response. (+info)