Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The immaturity of antioxidant capacity in the lung in preterm newborn infants is postulated to contribute to the development of hyperoxic lung injury. Antioxidant enzymes in fetal lung, comprised of copper-zinc (cytosolic) and manganese (mitochondrial) superoxide dismutases, glutathione peroxidase, and catalase, have been reported to increase during the late gestational period. To determine whether such maturation of antioxidant capacity occurs in other tissues, we have evaluated the development of these four enzymes from d 18 to 22 of gestation in rat lung, kidney, and heart. To resolve the confusion in the reported levels of lung superoxide dismutases, the two isoenzymes were assayed separately by specific RIA. The growth of the kidney exceeded that of the whole body during this period, while the growth of the lung and heart did not. The concentrations of the four antioxidant enzymes in lung and kidney increased in a stepwise manner during this period, and the magnitude of the change for each enzyme was greater in the kidney than in the lung. On the other hand, the only significant change in the concentrations of heart antioxidant enzymes observed was a mild increase in the glutathione peroxidase concentration from d 20 to 22. These results suggest that the prenatal maturation of antioxidant capacity occurs earlier in the heart and later in the kidney than in the lung, and that the immaturity of antioxidant capacity could make the fetal rat kidney vulnerable to free radical-mediated injury.
 ...
PMID:Prenatal development of antioxidant enzymes in rat lung, kidney, and heart: marked increase in immunoreactive superoxide dismutases, glutathione peroxidase, and catalase in the kidney. 234 74

Environmental toxicants such as metals may be detrimental to foetus and infant development and health because of their physiological immaturity, opportunistic and differential exposures, and a longer lifetime over which disease, initiated during pregnancy and in early life, can develop. The placental mechanisms responsible for regulation of absorption and excretion of elements during pregnancy are not fully understood. The aim of this paper is to assess the correlation for selected toxic and essential elements in paired whole blood samples of delivering women and cord blood, as well as to evaluate the placental permeability for selected elements. Regression analyses used to assess this correlation in 62-paired samples of maternal and cord whole blood of delivering women show that the concentrations of mercury, lead, cobalt, arsenic and selenium in maternal and cord blood differed statistically. Lead, cobalt, arsenic and selenium appear to pass the placental barrier by a diffusion mechanism. It was also found that the mercury levels in cord blood were almost double those of the mother, suggesting that the foetus may act as a filter for the maternal mercury levels during pregnancy. Transplacental transfer for arsenic and cobalt was 80% and 45%, respectively, suggesting that the placenta modulates the rate of transfer for these elements. Cadmium, manganese, copper and zinc levels did not show statistically significant correlations between two compartments (maternal versus cord whole blood). The study confirms that most of the toxic metals measured have an ability to cross the placental barrier.
 ...
PMID:The placenta as a barrier for toxic and essential elements in paired maternal and cord blood samples of South African delivering women. 2044 20

The rodents are an excellent model for understanding the development and plasticity of the visual system. In this study, we explored the feasibility of Mn-enhanced MRI (MEMRI) and diffusion tensor imaging (DTI) at 7 T for in vivo and longitudinal assessments of the retinal and callosal pathways in normal neonatal rodent brains and after early postnatal visual impairments. Along the retinal pathways, unilateral intravitreal Mn2+ injection resulted in Mn2+ uptake and transport in normal neonatal visual brains at postnatal days (P) 1, 5 and 10 with faster Mn2+ clearance than the adult brains at P60. The reorganization of retinocollicular projections was also detected by significant Mn2+ enhancement by 2%-10% in the ipsilateral superior colliculus (SC) of normal neonatal rats, normal adult mice and adult rats after neonatal monocular enucleation (ME) but not in normal adult rats or adult rats after monocular deprivation (MD). DTI showed a significantly higher fractional anisotropy (FA) by 21% in the optic nerve projected from the remaining eye of ME rats compared to normal rats at 6 weeks old, likely as a result of the retention of axons from the ipsilaterally uncrossed retinal ganglion cells, whereas the anterior and posterior retinal pathways projected from the enucleated or deprived eyes possessed lower FA after neonatal binocular enucleation (BE), ME and MD by 22%-56%, 18%-46% and 11%-15% respectively compared to normal rats, indicative of neurodegeneration or immaturity of white matter tracts. Along the visual callosal pathways, intracortical Mn2+ injection to the visual cortex of BE rats enhanced a larger projection volume by about 74% in the V1/V2 transition zone of the contralateral hemisphere compared to normal rats, without apparent DTI parametric changes in the splenium of corpus callosum. This suggested an adaptive change in interhemispheric connections and spatial specificity in the visual cortex upon early blindness. The results of this study may help determine the mechanisms of axonal uptake and transport, microstructural reorganization and functional activities in the living visual brains during development, diseases, plasticity and early interventions in a global and longitudinal setting.
 ...
PMID:In vivo evaluation of retinal and callosal projections in early postnatal development and plasticity using manganese-enhanced MRI and diffusion tensor imaging. 2198 4

Excess or inadequate levels of inorganic ions may induce significant acute and long-term irreversible dysfunction in humans. The fetus and placenta are particularly vulnerable to toxins due to the immaturity of the blood-brain barrier and diminished biotransformation enzymatic activity. A comparative cross-sectional study was conducted on 172 pregnant women, 79 rural, and 93 urban. Umbilical cord blood was collected at the time of delivery and analyzed for 20 inorganic elements. Significant differences were found between urban and rural samples for two elements where copper (Cu) and molybdenum (Mo) were higher in urban samples. No marked differences between groups occurred for: arsenic, barium, cadmium, calcium, cobalt, lead, lithium, magnesium, manganese, mercury, selenium, strontium, or zinc. All samples were devoid of platinum, silver, thallium or uranium. Data demonstrated significant differences in urban and rural prenatal exposure to Cu and Mo. Further study is needed to determine if there is a causal link between neonatal outcomes and prenatal exposure to these elements.
 ...
PMID:Rural and urban differences in prenatal exposure to essential and toxic elements. 3046 33