ABSTRACT
Hypoxia is a well-known signal for angiogenesis, but the recent proposal that hypoxia exists in developing embryonic tissues and that it induces vascular development remains to be proven. In the present study, we demonstrate the presence of hypoxia in normal developing embryos by means of a hypoxia marker, pimonidazole, and its associated antibody. Our data clearly show that hypoxia marker immunoreactivity was highly detected in developing neural tubes, heart, and intersomitic mesenchyme at an early stage of organogenesis, suggesting that hypoxia may exist in the early stages of embryo development. We also found that hypoxia inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) were spatiotemporally co-localized with possible hypoxic regions in embryos. Investigation of platelet endothelial cell adhesion molecule (PECAM) expression provides evidence that endothelial cells proliferate and form the vessels in the hypoxic region in developing organs. Furthermore, we found that hypoxia induced both HIF-1alpha and VEGF in F9 embryonic stem and differentiated cells. Thus, we suggest that hypoxia may exist widely in developing embryonic tissues and that it may act as a signal for embryonic blood vessel formation in vivo.
Subject(s)
Blood Vessels/embryology , Brain/embryology , DNA-Binding Proteins/genetics , Embryonic and Fetal Development/physiology , Endothelial Growth Factors/genetics , Endothelium, Vascular/embryology , Hypoxia , Lymphokines/genetics , Nuclear Proteins/genetics , Transcription Factors , Animals , Antibodies, Monoclonal , Biomarkers , Blood Vessels/cytology , Brain/cytology , Bucladesine/pharmacology , Cell Differentiation , Cell Hypoxia/physiology , DNA-Binding Proteins/analysis , Endothelial Growth Factors/analysis , Endothelium, Vascular/cytology , Gene Expression Regulation, Developmental , Hypoxia-Inducible Factor 1 , Hypoxia-Inducible Factor 1, alpha Subunit , Immunohistochemistry , Lymphokines/analysis , Mice , Mice, Inbred BALB C , Nitroimidazoles/analysis , Nitroimidazoles/immunology , Nuclear Proteins/analysis , Platelet Endothelial Cell Adhesion Molecule-1/analysis , Platelet Endothelial Cell Adhesion Molecule-1/genetics , Stem Cells/cytology , Stem Cells/drug effects , Stem Cells/physiology , Teratoma , Tumor Cells, Cultured , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth FactorsABSTRACT
In a study conducted to compare three screening methods for their ability to detect significant bacteriuria, 2,815 urine specimens were screened by Chemstrip LN (BioDynamics, Division of Boehringer Mannheim Chemicals, Indianapolis, Ind.), 1,000 were screened by Bac-T-Screen (Marion Scientific Laboratory, Kansas City, Mo.), and 289 were screened by ATP assay (Turner Designs, Mountain View, Calif.). Results were compared with those obtained by quantitative culture plate method. The ATP assay showed the highest sensitivity (91%) compared with the Bac-T-Screen (67%) and Chemstrip LN (50%) tests but had the lowest specificity (64%) compared with the Bac-T-Screen (83%) and Chemstrip LN (91%). In 101 leukopenic patients with significant bacteriuria, the Bac-T-Screen test showed a higher sensitivity (33% at 10(4) to 10(5) CFU/ml and 80% at greater than or equal to 10(5) CFU/ml). It is concluded from this study that none of the three methods are sufficiently sensitive for the clinical research patients in this institution.
Subject(s)
Bacteriuria/diagnosis , Adenosine Triphosphate/analysis , Esterases/blood , Evaluation Studies as Topic , Humans , Leukocyte Count , Leukocytes/enzymology , Reagent StripsABSTRACT
Three commercial latex kits, IBL, MYCO-Immune, and IMMY, for the detection of cryptococcal antigen were compared in regard to sensitivity, specificity, and height of antigen titers. A total of 218 cerebrospinal fluid and 79 serum specimens from 239 patients were included. Twenty-two patients had culture-proven disseminated cryptococcosis. Both the IBL and MYCO-Immune kits had sensitivities of 100%, and the IMMY kit had sensitivities of 82.6 and 45.4% in CSF and serum specimens, respectively. There was one false-positive reaction in serum with the MYCO-Immune kit and one false-negative reaction on screen only with all three kits. Rheumatoid factor-containing sera were used to check the agglutination titers between matching anti-cryptococcal globulin reagents and normal globulin reagents. The finding that agglutination titer with anti-cryptococcal globulin reagents was fourfold higher than with normal globulin reagents in the MYCO-Immune kit is considered to be a cause for a false-positive reaction in serum.
