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

Pituitary GH secretion appears largely unnecessary for the attainment of normal birth size in many species, including man. This is believed to be due to an immaturity and/or an absence of GH receptors in many fetal tissues. However, in vitro studies using late first trimester human fetal tissues have demonstrated mitogenic actions of GH on liver and stimulation of insulin biosynthesis in pancreas. To resolve this discrepancy, we have employed immunocytochemistry to identify the presence and distribution of GH receptors in various human fetal tissues. Fetuses of 14-16 weeks gestation were obtained after therapeutic abortion, tissues were fixed, and immunocytochemistry was performed using monoclonal antibodies against purified rat or rabbit GH receptor. The specificity of staining was confirmed by preabsorption of the antibodies with 1) adult rat liver membranes or 2) human fetal liver membranes, both of which possess specific GH-binding sites, or 3) human fetal skeletal muscle membranes, which do not specifically bind GH. Positive staining was seen in a subpopulation of liver parenchymal cells, in the ductal and endocrine tissue of pancreas, in the germinal layer of the epidermis and the deeper dermal layers of skin, and in the tubular epithelium of kidney. No immunopositive staining was seen in skeletal or cardiac muscle, epiphyseal growth plate, lung, intestine, or adrenal. Positive staining was present in the neuronal cell bodies of the cerebral cortex. GH receptor was also detectable as early as 8 weeks gestation in syncytial layers of the placenta and was maintained until term. Results demonstrate the presence of immunoreactive GH receptor/binding protein in some human fetal tissues early in development. In particular, these results would support a role for GH in the growth and function of liver and pancreas.
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PMID:Localization of the growth hormone receptor, identified by immunocytochemistry, in second trimester human fetal tissues and in placenta throughout gestation. 137 61

LoxP-Cre technology was used to remove the selenocysteine tRNA gene, trsp, in either endothelial cells or myocytes of skeletal and heart muscle to elucidate the role of selenoproteins in cardiovascular disease. Loss of selenoprotein expression in endothelial cells was embryonic lethal. A 14.5-day-old embryo had numerous abnormalities including necrosis of the central nervous system, subcutaneous hemorrhage and erythrocyte immaturity. Loss of selenoprotein expression in myocytes manifested no apparent phenotype until about day 12 after birth. Affected mice had decreased mobility and an increased respiratory rate, which proceeded rapidly to death. Pathological analysis revealed that mice lacking trsp had moderate to severe myocarditis with inflammation extending into the mediastinitis. Thus, ablation of selenoprotein expression demonstrated an essential role of selenoproteins in endothelial cell development and in proper cardiac muscle function. The data suggest a direct connection between the loss of selenoprotein expression in these cell types and cardiovascular disease.
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PMID:Selenoprotein expression is essential in endothelial cell development and cardiac muscle function. 1714 41

A 2-year-old, male Weimaraner with muscular dystrophy was presented with generalized muscle atrophy of the limbs; hypertrophy of the neck, infraspinatus, and lingual muscles; dysphagia; and regurgitation. Unilateral cryptorchidism, unilateral renal agenesis, and hiatal hernia were also detected. Spontaneous muscle activity was identified on myography. Serum creatine kinase was markedly elevated. Immunohistochemical staining for dystrophin was restricted to suspected revertant (characteristics of immaturity) fibers. Histologically, skeletal myofiber degeneration, endomysial fibrosis, and mineralization were present. Following euthanasia, necropsy revealed hypertrophy of the diaphragm and cardiac muscle fibrosis. This case of muscular dystrophy represents a slowly progressive form with organ agenesis.
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PMID:Dystrophin-deficient muscular dystrophy in a Weimaraner. 1761 4

Supporting or even replacing diseased myocardium with in vitro engineered heart muscle may become a viable option for patients with heart failure. The key to success will be to (1) generate human heart muscle equivalents in vitro, (2) integrate the latter into a failing heart, (3) ensure long-term functional competence of the grafts, and (4) prevent unwanted effects including arrhythmias, inflammation/rejection, and tumor formation. Several promising tissue engineering technologies have already been developed and are presently being tested in animal models. The rapidly evolving field of human stem cell biology has in parallel identified unique cell sources of potential clinical relevance. Somatic cell reprogramming and nontransduced, nonembryonic pluripotent stem cells may be of particular interest to eventually provide patient-specific cells and tissues. Yet, limited cardiac differentiation and cell immaturity still restrict a broad application of any stem cell type in cardiac muscle engineering. Bioreactor technologies, transgenic "optimization," and growth factor, as well as physical conditioning, have been used to address these caveats. This review summarizes different tissue engineering modalities, speculates on potential clinical uses, provides an overview on cell sources that may ultimately facilitate a patient-specific application, and discusses limitations of tissue engineering-based myocardial repair.
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PMID:Remuscularizing failing hearts with tissue engineered myocardium. 1920 22

Over the last decade or so, intensive research in cardiac stem cell biology has led to significant discoveries towards a potential therapy for cardiovascular disease; the main cause of morbidity and mortality in humans. The major goal within the field of cardiovascular regenerative medicine is to replace lost or damaged cardiac muscle and coronaries following ischaemic disease. At present, de novo cardiomyocytes can be generated either in vitro, for cell transplantation or disease modelling using directed differentiation of embryonic stem cells or induced pluripotent stem cells, or in vivo via direct reprogramming of resident adult cardiac fibroblast or ectopic stimulation of resident cardiac stem or progenitor cells. A major bottleneck with all of these approaches is the low efficiency of cardiomyocyte differentiation alongside their relative functional immaturity. Chemical genetics, and the application of phenotypic screening with small molecule libraries, represent a means to enhance understanding of the molecular pathways controlling cardiovascular cell differentiation and, moreover, offer the potential for discovery of new drugs to invoke heart repair and regeneration. Here, we review the potential of chemical genetics in cardiac stem cell therapy, highlighting not only the major contributions to the field so far, but also the future challenges.
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PMID:Chemical genetics and its potential in cardiac stem cell therapy. 2238 48