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Find video protocols related to scientific articles indexed in Pubmed.
Quantification and localization of erythropoietin-receptor-expressing cells in the liver of Xenopus laevis.
Cell Tissue Res.
PUBLISHED: 04-01-2013
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Erythropoiesis occurs in the African clawed frog, Xenopus laevis and is mediated by erythropoietin (xlEPO), a primary regulator of this process. Previously, we have shown that the xlEPO receptor (xlEPOR), which is expressed by erythroid progenitors that respond to xlEPO, is found predominantly in the liver. The aim of the present study was to determine the dynamics of erythropoiesis in the livers of normal and anemic X. laevis by identifying the number and precise location of mature and immature erythrocytes. We quantified mature and immature erythrocyte numbers by o-dianisidine staining or immunohistochemistry and investigated the dynamics of erythropoiesis in normal, acute hemolytic and blood-loss states by in vivo cell proliferation assays with 5-bromo-2-deoxyuridine (BrdU). We detected 0.12×10(8) xlEPOR(+) BrdU(+) cells in the liver of the normal X. laevis at 24 h after BrdU injection. Frogs presenting with acute hemolytic anemia and pancytopenia show a 10-fold increase in the number of xlEPOR(+)/BrdU(+) cells (approximately 1.30×10(8) cells) in the liver. The xlEPOR(+) cells are found predominantly on the inner wall of hepatic sinusoids. Hematopoietic progenitors that undergo slow cell cycling were also observed in the hepatic sinusoids. This study clarifies the rate of production of mature and immature erythrocytes per day in the liver of X. laevis and the way that these cell numbers change in response to anemia.
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Transcription Profiles of Endothelial Cells in the Rat Ductus Arteriosus during a Perinatal Period.
PLoS ONE
PUBLISHED: 01-01-2013
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Endothelial cells (ECs) lining the blood vessels serve a variety of functions and play a central role in the homeostasis of the circulatory system. Since the ductus arteriosus (DA) has different arterial characteristics from its connecting vessels, we hypothesized that ECs of the DA exhibited a unique gene profile involved in the regulation of DA-specific morphology and function. Using a fluorescence-activated cell sorter, we isolated ECs from pooled tissues from the DA or the descending aorta of Wistar rat fetuses at full-term of gestation (F group) or neonates 30 minutes after birth (N group). Using anti-CD31 and anti-CD45 antibodies as cell surface markers for ECs and hematopoietic derived cells, respectively, cDNAs from the CD31-positive and CD45-negative cells were hybridized to the Affymetrix GeneChip® Rat Gene 1.0 ST Array. Among 26,469 gene-level probe sets, 82 genes in the F group and 81 genes in the N group were expressed at higher levels in DA ECs than in aortic ECs (p<0.05, fold change>2.0). In addition to well-known endothelium-enriched genes such as Tgfb2 and Vegfa, novel DA endothelium-dominant genes including Slc38a1, Capn6, and Lrat were discovered. Enrichment analysis using GeneGo MetaCore software showed that DA endothelium-related biological processes were involved in morphogenesis and development. We identified many overlapping genes in each process including neural crest-related genes (Hoxa1, Hoxa4, and Hand2, etc) and the second heart field-related genes (Tbx1, Isl1, and Fgf10, etc). Moreover, we found that regulation of epithelial-to-mesenchymal transition, cell adhesion, and retinol metabolism are the active pathways involved in the network via potential interactions with many of the identified genes to form DA-specific endothelia. In conclusion, the present study uncovered several significant differences of the transcriptional profile between the DA and aortic ECs. Newly identified DA endothelium-dominant genes may play an important role in DA-specific functional and morphologic characteristics.
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[Remifentanil prevents hyperglycemia and reduces insulin use during cardiopulmonary bypass in adult cardiac surgery].
Masui
PUBLISHED: 04-28-2011
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Remifentanil may be beneficial in patients undergoing cardiac surgery, by attenuating the neurohumoral stress response to surgical stimulation and inflammation evoked by cardiopulmonary bypass (CPB).
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Identification of erythroid progenitors induced by erythropoietic activity in Xenopus laevis.
J. Exp. Biol.
PUBLISHED: 02-25-2011
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Oxygen is essential for the survival of animals. Red blood cells in the circulation, i.e. peripheral erythrocytes, are responsible for transporting oxygen to tissues. The regulation of erythropoiesis in vertebrates other than mammals is yet to be elucidated. Recently we identified erythropoietin, a primary regulator of erythropoiesis, in Xenopus laevis, which should enable us to identify target cells, including erythroid progenitors, and to investigate the production and development of erythroid cells in amphibians. Here, we established a semi-solid colony-forming assay in Xenopus laevis to clarify the existence of colony-forming unit-erythroid cells, the functional erythroid progenitors identified in vitro. Using this assay, we showed that recombinant xlEPO induces erythroid colony formation in vitro and detected an increased level of erythropoietin activity in blood serum during acute anemic stress. In addition, our study demonstrated the possible presence of multiple, non-xlEPO, factors in anemic serum supportive of erythroid colony formation. These results indicate that erythropoiesis mediated by erythropoietin is present in amphibian species and, furthermore, that the regulatory mechanisms controlling peripheral erythrocyte number may vary among vertebrates.
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Enhanced erythropoiesis in mice exposed to low environmental temperature.
J. Exp. Biol.
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Hematopoietic responses to environmental factors are not fully characterized. Polycythemia has been reported during exposure to low temperatures in ectothermic animals. The relationship between the causes of polycythemia and erythropoiesis during low temperature exposure is not fully understood. In this study, we exposed C57BL/6 mice to 5°C and monitored the blood cell counts and erythropoiesis. The hematocrit level increased from 45.6 to 52.2% after 14 days. Likewise, the hemoglobin concentration, initially 15.1 g dl(-1), rose to 16.0 g dl(-1). The reticulocyte production index significantly increased from 4 to 8% after 7 days. We examined the anatomy and cell composition of the spleens of the mice. On day 5, the spleens were ?6 mg g(-1) of body mass, which was twofold greater than the spleens on day 0. Flow cytometry showed fourfold more proerythroblasts on day 5, compared with day 0. Additionally, the number of late-stage mature erythroblasts increased on day 14. Erythropoietin mRNA levels increased in the kidneys, and hypoxia-inducible genes were enhanced in the kidney. Our findings indicated that low ambient temperature is a novel erythropoietic stress, which induces polycythemia by enhanced erythropoiesis.
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Hepatic confinement of newly produced erythrocytes caused by low-temperature exposure in Xenopus laevis.
J. Exp. Biol.
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Diminished erythrocyte count and erythropoiesis have been reported during hypothermia in some ectothermic animals. In this study, the African clawed frog, Xenopus laevis, was used to investigate the cause of hypothermia-induced anemia. We developed a new model of hypothermia at 5°C and monitored blood cell count and erythropoiesis on several days. Erythrocyte count declined by 30% on the first day following cold exposure (5°C) and mRNA expression of hemeoxygenase-1 was enhanced 10-fold; accumulation of iron as a result of heme degradation was observed in the liver. One day after low-temperature exposure, erythropoietin mRNA expression was elevated in the liver and lung compared with that at normal temperature (22°C) by qRT-PCR analysis. Examination of liver sections (i.e. the erythropoietic organ) showed an increase in o-dianisidine-positive erythrocytes in the hepatic sinusoid 5 days after the onset of low-temperature exposure compared with normal liver. Peripheral erythrocyte count remained low, indicating that newly produced erythrocytes did not migrate from the liver to the circulation during hypothermia. In conclusion, this study reveals hypothermic anemia as being associated with hepatic erythrocyte destruction; prolonged anemia during low-temperature exposure is concomitant with newly produced erythrocytes being confined to the liver and may lead to new insights into vertebrate hematopoiesis.
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Synthesis and bioassay of a boron-dipyrromethene derivative of estradiol for fluorescence imaging in vivo.
Steroids
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C7?-substituted estradiols bind to estrogen receptors in cell nuclei, yet these derivatives remain little used in bioimaging. Here, we describe a fluorescent derivative of estradiol (E2) with a boron-dipyrromethene (BODIPY) moiety attached to C7?, synthesized by olefin metathesis reaction of 7?-allylestradiol and 9-decenyl-BODIPY. In ovariectomized rats and non-ovariectomized mice, E2-BODIPY promoted the growth of uterine tissue similar to the effect of estradiol. Twenty-four hours after subcutaneous injection of E2-BODIPY in non-ovariectomized mice, we observed fluorescence of E2-BODIPY in the nuclei of uterine epithelial cells. Our findings suggest that fluorescence microscopy can localize this derivative in E2-responsive cells during normal development and tumorigenesis in vivo.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.