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Query: UMLS:C0029713 (
immaturity
)
4,335
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The effects of the low neutral endopeptidase (24.11/CD10) exhibited by cord blood neutrophils on response to the peptide mediator of cell function f-met-leu-phe (fMLP) were investigated. Oxidative radical release (superoxide and hydrogen peroxide) and chemotactic responses to fMLP were determined and compared to the responses of normal adult neutrophils. The effect of fMLP on CD10 expression as measured by flow cytometry also was evaluated. The data show that cord blood neutrophils produce increased amounts of O2- and
H2O2
largely because of a prolonged reaction time to fMLP. In addition, adult polymorphonuclear neutrophil leukocytes increase the intensity of their expression of CD10 following fMLP stimulation, whereas cord blood CD10 expression does not change. Evaluation of chemotaxis demonstrated that cord blood neutrophils exhibited a shift in the fMLP dose-response relationship showing relatively better chemotaxis to lower concentrations. In support of this observation, the inhibition of endopeptidase on adult polymorphonuclear neutrophils leukocytes by phosphoramidon was associated with an augmentation of chemotaxis to 10(-9) and 10(-10) mol/L fMLP. These studies demonstrate that cord blood and adult neutrophils respond differently to fMLP and suggest that membrane endopeptidase plays a role in the observed response patterns. The low level of expression of CD10 on cord blood neutrophils and the failure to increase its expression after fMLP stimulation suggests that adult neutrophils have preformed intracellular CD10 that is not present in the newborn. We propose that the lack of endopeptidase on cord blood neutrophils together with other known features of
immaturity
may play a role in the overall compromised host defense exhibited by the newborn.
...
PMID:Effect of low neutral endopeptidase expression on response to fMLP. 145 99
The present study was designed to evaluate the validity of luminol-dependent chemiluminescence (CL) to evaluate the microbicidal properties of alveolar macrophages (AM) in response to drugs. It was observed that production of CL is associated with
H2O2
as well as O2-, 1O2, .OH. Furthermore, our data revealed that CL is dependent not only upon the extracellular release of these oxygen radicals, but also upon intracellular metabolic events, which thus allows a complete analytical study in any given state. It should also be noted from our data that the effect of antibacterial agents on CL was greatly affected by the source of the target cells. The defect of amplified CL in AM obtained from young rabbits might be attributable to
immaturity
of AM.
...
PMID:[Luminol-amplified chemiluminescence evaluation of the microbicidal property of alveolar macrophages in response to drugs]. 261
The nature of the aging process has been the subject of considerable speculation. Now, some data indicate that free radical reactions going on continuously in the cells contribute to aging. Considering these data, we have investigated the activity of enzymes (catalase, glutathione peroxidase, superoxidismutase) present physiologically in the cell to limit to tolerable levels, the rate of free radicals or
H2O2
. These enzymes activities were assayed in Paramecium tetraurelia as clonal age increased. Catalase activity increases slightly during aging of paramecia, i.e. during maturity and senescence phases (20-150 fissions). No significant changes in glutathione peroxidase and superoxidismutase is found. Catalase activity was also assayed as a function of culture conditions. As the cells begin starving and the percentage of autogamous cells increases, catalase activity decreases. After autogamy, a large increase of catalase activity occurs during the sexual
immaturity
phase, i.e. during the first 20 fissions. By another way,
H2O2
added in the culture medium (from 0 to 15 X 10(-5)M) causes an important increase of catalase activity (from 100 U.I. to 250 U.I.). The possible role of O-.2, OH. and
H2O2
in aging is discussed.
...
PMID:Studies on catalase, glutathione peroxidase and superoxidismutase activities in aging cells of Paramecium tetraurelia. 398 82
To quantitate the developmental changes in selenium-dependent cellular glutathione peroxidase during the perinatal period, tissue sections from foetal (day 12 to day 22) and neonatal (day 6) rats were stained immunohistochemically using specific polyclonal antiserum. The intensity of the staining was quantified by fluorescence microscopy image analysis. There was a general trend of enriched glutathione peroxidase in the epithelial linings and metabolically active sites. Significant fluorescence was detected in cardiomyocytes, hepatocytes, renal tubular epithelium, bronchiolar epithelium and intestinal epithelium at day 15. The intensity increased in a stepwise manner thereafter. The overall increase in the intensity of staining in the heart, liver, kidneys, lungs and intestine was 1.5-, 2.3-, 1.6-, 1.7- and 3.0-fold, respectively. The phase of most rapid increase occurred during the foetal period in the liver, intestine and heart. In the kidneys and lungs, glutathione peroxidase increased significantly during foetal life, and to a similar extent postnatally. These results suggest that the intracellular
H2O2
-scavenging system develops during the foetal period as an essential mechanism for living under atmospheric oxygen conditions. The late development observed in the kidneys and lungs is consistent with the relative biological
immaturity
of these organs in full-term neonates.
...
PMID:Immunohistochemical localization and quantitative analysis of cellular glutathione peroxidase in foetal and neonatal rat tissues: fluorescence microscopy image analysis. 886 49
The neonatal brain appears to be selectively vulnerable to oxidative stress. Several potential mechanisms associated with altered reactive oxygen species metabolism would explain the increased susceptibility. They include increased accumulation of hydrogen peroxide with subsequent neurotoxicity. This enhanced neurotoxicity from
H2O2
accumulation may be related to inadequate scavenging abilities of the immature nervous system, such as lower glutathione peroxidase activity. Contributing to the
immaturity
of the scavenging enzymes is the inability of the developing nervous system to maintain glutathione stores. The immature nervous system is rich in iron, and has more free iron than the mature nervous system. As
H2O2
accumulates because of these improper defense mechanisms, it is exposed to this free iron. This exposure results in the generation of OH radical (Fenton reaction), a more potent free radical that can cause severe damage. The rapid conversion of
H2O2
to OH in the setting of free iron sets up the immature nervous system for increased cytotoxicity. Understanding the molecular mechanisms of oxidative stress will lead to better therapies for neonatal hypoxia-ischemia.
...
PMID:Oxidant mechanisms in neonatal hypoxia-ischemia. 1159 20
Hydrogen peroxide
(H
2
O
2
) is emerging as a new second messenger, which plays vital roles in intracellular signaling, thereby triggering physiological variations in terms of proliferation, differentiation, and migration. As known, cell mitosis has close association to the intracellular level of H
2
O
2
, which contribute to the significant effects on brain development, especially during the critical period of
immaturity
. Unfortunately, imaging H
2
O
2
in a mammalian brain is still challenging. Herein, to further investigate the biological roles of endogenous H
2
O
2
in cell mitosis, we develop a near-infrared ratiometric fluorescent probe Cy-PFS for specifically imaging endogenous H
2
O
2
in cells and in vivo. Employing the probe Cy-PFS, we examine the critical effects of endogenous H
2
O
2
on proliferation of cells in live hippocampal neurons cells, and our results provide strong evidence for H
2
O
2
signaling in cell mitosis through growth factor signaling. Furthermore, we successfully demonstrate the close association of endogenous H
2
O
2
level changes with the brain development at various stages. We envision that this present probe has potential as a promising useful chemical imaging tool for exploring the roles of H
2
O
2
in cell mitosis.
...
PMID:Imaging of Endogenous Hydrogen Peroxide during the Process of Cell Mitosis and Mouse Brain Development with a Near-Infrared Ratiometric Fluorescent Probe. 3051 72
