RESUMEN
The effects of DNA repair and transcription gene abnormalities in human pre-natal life have never been studied. Trichothiodystrophy (TTD) is a rare (affected frequency of 10(-6)) recessive disorder caused by mutations in genes involved in nucleotide excision repair (NER) pathway and in transcription. Based on our novel clinical observations, we conducted a genetic epidemiologic study to investigate gestational outcomes associated with TTD. We compared pregnancies resulting in TTD-affected offspring (n = 24) with respect to abnormalities during their antenatal and neonatal periods to pregnancies resulting in their unaffected siblings (n = 18), accounting for correlation, and to population reference values. Significantly higher incidence of several severe gestational complications was noted in TTD-affected pregnancies. Small for gestational age (SGA) <10th percentile [Relative risk (RR ) = 9.3, 95% CI = 1.4-60.5, p = 0.02], SGA <3rd percentile (RR = 7.2, 95% CI = 1.1-48.1, p = 0.04), and neonatal intensive care unit (NICU) hospitalization (RR = 6.4, 95% CI = 1.4-29.5, p = 0.02) occurred more frequently among TTD-affected neonates compared with their unaffected siblings. Compared with reference values from general obstetrical population, pregnancies that resulted in TTD-affected infants were significantly more likely to be complicated by hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome (RR = 35.7, 95% CI = 7.6-92.5, p = 0.0002), elevated mid-trimester maternal serum human chorionic gonadotropin (hCG) levels (RR = 14.3, 95% CI = 7.0-16.6, p < 0.0001), SGA <3rd percentile (RR = 13.9, 95% CI = 7.4-21.1, p < 0.0001), pre-term delivery (<32 weeks) (RR = 12.0, 95% CI = 4.9-21.6, p < 0.0001), pre-eclampsia (RR = 4.0, 95% CI = 1.6-7.4, p = 0.006), and decreased fetal movement (RR = 3.3, 95% CI = 1.6-5.2, p = 0.0018). Abnormal placental development is an underlying mechanism that may explain the constellation of observed complications in our study. Thus, we hypothesize that TTD DNA repair and transcription genes play an important role in normal human placental development.
Asunto(s)
Reparación del ADN/genética , Desarrollo Fetal/genética , Transcripción Genética , Síndromes de Tricotiodistrofia/embriología , Síndromes de Tricotiodistrofia/genética , Adulto , Demografía , Familia , Femenino , Humanos , Nacimiento Vivo , Persona de Mediana Edad , Embarazo , Resultado del Embarazo , Valores de Referencia , Adulto JovenRESUMEN
DW-116 is a newly developed fluoroquinolone antibacterial with a broad spectrum against both Gram-positive and Gram-negative bacteria. We have reported recently that DW-116 is embryotoxic and teratogenic in rats. The present study was conducted to investigate the teratogenicity of DW-116, together with maternal toxicity and developmental toxicity using New Zealand White rabbits. The test chemical was administered by gavage to pregnant rabbits from gestational day (GD) 6 through to GD 18 at dose levels of 0, 5, 19.5 and 76.1 mg kg(-1) day(-1). All does were subjected to caesarean section on day 28 of gestation and their foetuses were examined for external, visceral and skeletal abnormalities. In the 76.1 mg kg(-1) group, a minimal maternal toxicity, as evidenced by decreased body weight gain during treatment period, was observed in pregnant rabbits. Significant embryo-foetal toxicity, including increased number of foetal deaths and delayed foetal ossification, was seen. However, no treatment-related morphological changes were detected in foetal external, visceral and skeletal examinations. There were no adverse effects on either pregnant dams or embryo-foetal development at 19.5 and 5 mg kg(-1). It was concluded that administration of DW-116 during the major organogenetic period in rabbits produced decreased maternal body weight gain, increased number of foetal deaths and foetal developmental delay but no evidence of teratogenicity. The no-observed-adverse-effect levels (NOAELs) of DW-116 are considered to be 19.5 mg kg(-1) day(-1) for does and embryo-foetuses, respectively.
Asunto(s)
Antibacterianos/toxicidad , Evaluación Preclínica de Medicamentos , Desarrollo Embrionario/efectos de los fármacos , Fluoroquinolonas/toxicidad , Piperazinas/toxicidad , Quinolonas/toxicidad , Animales , Antibacterianos/química , Peso Corporal/efectos de los fármacos , Femenino , Muerte Fetal/inducido químicamente , Fluoroquinolonas/química , Edad Gestacional , Estructura Molecular , Nivel sin Efectos Adversos Observados , Piperazinas/química , Embarazo , Quinolonas/química , ConejosRESUMEN
Effect of the aqueous extract from a medicinal plant Dryobalanops aromatica(Dipterocarpaceae) on catecholamine secretion was investigated in bovine adrenal chromaffin cells. The aqueous extract inhibited [(3)H]norepinephrine ([(3)H]NE) secretion induced by 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), a nicotinic acetylcholine receptor (nAChR) agonist, with a half-maximal inhibitory concentration (IC(50)) of 8.4 +/- 1.7 microgml(-1). Increases in cytosolic calcium ([Ca(2+)](i)) and sodium ([Na(+)](i)) induced by DMPP were also inhibited by the extract. However, the binding of [(3)H]nicotine to nAChRs was not affected by the addition of the extract in receptor binding competition analysis, suggesting that active components in the extract and nicotine do not share the binding site in the nAChR. On the other hand, [Ca(2+)](i)increases induced by high K(+), ionomycin, bradykinin, angiotensin II, and thapsigargin were not inhibited by the extract. The data suggest that the extract from D. aromatica specifically inhibits catecholamine secretion by blocking nAChR in a noncompetitive manner.
Asunto(s)
Células Cromafines/efectos de los fármacos , Antagonistas Nicotínicos/farmacología , Norepinefrina/metabolismo , Plantas Medicinales , Receptores Nicotínicos/efectos de los fármacos , Animales , Calcio/metabolismo , Bovinos , Células Cromafines/metabolismo , Yoduro de Dimetilfenilpiperazina/farmacología , Relación Dosis-Respuesta a Droga , Nicotina/metabolismo , Extractos Vegetales/farmacología , Receptores Nicotínicos/fisiologíaRESUMEN
GABAergic inhibition synchronizes oscillatory activity in the thalamocortical system. To understand better the role of this neurotransmitter in generation of thalamocortical rhythmicity, the postnatal development of GABAergic function mediated through activation of GABAA receptors was studied in thalamus and cortex. GABA-evoked chloride currents were recorded in dissociated rat cortical and thalamic neurons during postnatal development. Kinetic fits of GABA concentration/response relationships revealed developmental and regional alterations in the potency of GABA. Early in postnatal development (p5-p8), both thalamic and cortical neurons exhibited reduced potency of GABA (27-31 microM KD). Potency increased by p18-p25 in thalamic and cortical neurons (19-22 microM KD), to a level maintained in adult thalamic neurons. Adult cortical neurons exhibited reduced potency of GABA (40 microM KD). Benzodiazepine modulation of GABAA currents was also studied. Kinetic analyses of benzodiazepine augmentation of GABAA currents were best fitted assuming two effective sites with different affinities for clonazepam. The high-affinity site (KD of 0.05-0.27 nM) showed little variation with development in cortical neurons, contributing about 16-23% potentiation at all postnatal ages. Developing thalamic neurons (p5-p25) showed similar potency and efficacy of the high-affinity benzodiazepine site to cortical neurons. High-affinity benzodiazepine effects disappeared in adult thalamic neurons. A lower-affinity benzodiazepine site (25-50 nM KD) was greater in efficacy in cortical neurons compared to thalamic neurons at all ages, with efficacy ranging from 50% to 110% in cortex and from 20% to 60% in thalamus. Knowledge of developmental and regional alterations in GABAA receptor function may aid in understanding mechanisms involved in generation and control of normal and pathological thalamocortical rhythms.
Asunto(s)
Envejecimiento/metabolismo , Neuronas/metabolismo , Receptores de GABA/metabolismo , Corteza Somatosensorial/metabolismo , Tálamo/metabolismo , Animales , Animales Recién Nacidos , Separación Celular , Cloruros/fisiología , Clonazepam/farmacología , Electrofisiología , Neuronas/fisiología , Ratas , Corteza Somatosensorial/citología , Corteza Somatosensorial/fisiología , Tálamo/citología , Tálamo/fisiologíaRESUMEN
Two very low birthweight infants with rickets are described; one had a low serum 25-hydroxy-vitamin D3 concentration. Similarities in their clinical courses included low birthweights, low calcium intakes, uncertain vitamin D intakes, and chronic administration of frusemide and sodium bicarbonate--all potential aetiological factors in the development of bone undermineralisation. Both infants had a resolution of their chronic lung disease before their treatment for rickets. This experience has led us to the more cautions use of frusemide and sodium bicarbonate in infants at risk for rickets, and shows the need to ensure daily vitamin D supplements.