Biomedical subjects

Xiangrong Kong

Publications and source records attributed to Xiangrong Kong.

3 recordsLinked to original sources

PubMed2006

SScore: an R package for detecting differential gene expression without gene expression summaries.

SUMMARY: SScore is an R package that facilitates the comparison of gene expression between Affymetrix GeneChips using the S-score algorithm. The S-score algorithm uses probe level data directly to assess differences in gene expression, without requiring a preliminary separate step of probe set expression summary estimation. Therefore, the algorithm avoids introduction of error associated with the expression summary estimation process and has been demonstrated to improve the accuracy of identifying differentially expressed genes. The S-score produces accurate results even when few or no replicates are available. AVAILABILITY: The R package SScore is available from Bioconductor at http://www.bioconductor.org

Algorithms↗

PubMed2004

Enhanced recovery from thrombocytopenia and neutropenia in mice constitutively expressing a placental hematopoietic cytokine.

Expression of the placental hormone, prolactin-like protein E (PLP-E), a potent cytokine that acts on multiple myeloid lineages, is normally restricted to pregnancy and certain hematopoietic disease states. We hypothesized that the restricted pattern of PLP-E expression is necessary to avoid hyperstimulation of myelopoiesis. To test this idea, we have produced PLP-E transgenic mice and analyzed their steady-state blood cell levels. We find that blood cell levels remain in the normal range, and thus the constitutive expression of a cytokine of pregnancy fails to overcome the tight control of hematopoietic set points for blood cell levels. In contrast, an effect of constitutive PLP-E expression is detected during the recovery from low blood platelet levels (acute thrombocytopenia) and from low granulocyte levels (acute neutropenia) but not from anemia. Mice producing high circulating concentrations of PLP-E recover more rapidly from both thrombocytopenia and neutropenia, as seen both by an earlier increase of progenitor numbers in the bone marrow and the earlier return to normal circulating blood cell levels.

Anemia↗

PubMed2002

Activation of protein kinases in chronically hypoxic infant human and rabbit hearts: role in cardioprotection.

BACKGROUND: Many infants who undergo heart surgery have a congenital cyanotic defect in which the heart is chronically perfused with hypoxic blood. However, the signaling pathways by which infant hearts adapt to chronic hypoxia and resist subsequent surgical ischemia is unknown. METHODS AND RESULTS: We determined the activation and translocation of protein kinase C (PKC) isoforms and mitogen activated protein kinases (MAP kinases) in 15 infants with cyanotic (SaO2<85%) or acyanotic (SaO2>95%) heart defects undergoing surgical repair and in 80 rabbits raised from birth in a hypoxic (SaO2<85%) or normoxic (SaO2>95%) environment. Tissues from infant human and rabbit hearts were processed for Western and in vitro kinase analysis. In human infants with cyanotic heart defects, PKCepsilon, p38 MAP kinase, and JUN kinase but not p42/44 MAP kinase were activated and translocated from the cytosolic to the particulate fraction compared with acyanotic heart defects. In rabbit infants there was a parallel response for PKCepsilon, p38 MAP kinase, and JUN kinase similar to humans. In infant rabbit hearts inhibition of PKCepsilon with chelerythrine, p38 MAP kinase, with SB203580 and JUN kinase with curcumin abolished the cardioprotective effects of chronic hypoxia but had no effects on normoxic hearts. CONCLUSIONS: Infant human and rabbit hearts adapt to chronic hypoxia through activation of PKCepsilon, p38 MAP kinase, and JUN kinase signal transduction pathways. These pathways may be responsible for cardioprotection in the chronically hypoxic infant rabbit heart.

Activating Transcription Factor 2↗