Crystal Dawn - Academia.edu (original) (raw)
Papers by Crystal Dawn
Handbook of Obesity Intervention for the Lifespan, 2008
Vaccine, 2001
The fate of T cell responses to peptide-based vaccination is subject to constraints by the major ... more The fate of T cell responses to peptide-based vaccination is subject to constraints by the major histocompatibility complex (MHC), MHC restriction. Using as a model system of T and B cell epitopes from the circumsporozoite protein of Plasmodium falciparum malaria parasite, we show that vaccination by somatic transgene immunization readily primes Balb/c mice (H-2(d)) a strain previously reported to be non-responder to immunization with a synthetic peptide vaccine encompassing these epitopes. Following genetic vaccination Balb/c mice developed a primary T cell response comparable to that of the responder strain C57Bl/6 (H-2(b)). Following booster immunization on day 45 Balb/c mice responded with a typical T cell memory response. Priming induced the formation of specific antibodies, which rose sharply after booster immunization. These findings suggests that genetic immunization can circumvent MHC class II restriction.
TAG Theoretical and Applied Genetics, 2002
Transgenic Brassica napus can be easily crossed with wild Brassica rapa. The spread of the transg... more Transgenic Brassica napus can be easily crossed with wild Brassica rapa. The spread of the transgene to wild species has aroused the general concern about its effect on ecological and agricultural systems. This paper was designated, by means of population genetics, to study the fate of a transgene escape from B. napus to B. rapa. Three models were proposed to survey the change in gene frequency during successive backcross processes by considering selection pressures against aneuploids, against herbicide-susceptible individuals, and by considering A-C intergenomic recombination and the effect of genetic drift. The transmission rate of an A-chromosome gene through an individual to the next generation was 50%, irrespective of the chromosome number; while that of a C-chromosome transgene varied from 8.7% to 39.9%, depending on the chromosome number of the individual used in the backcross. Without spraying herbicide, the frequency of an A-chromosome gene was 50% in the BC 1 generation, and decreased by 50% with the advance of each backcross generation; that of a C-chromosome gene was around 39.9% in BC 1 , 7.7% in BC 2 , 1.2% in BC 3 and 0.1% in the BC 4 generation. Under the selection pressure against herbicide-susceptible individuals, the frequency of a transgene reached a stable value of about 5.5% within six generations of successive backcrossings. The effect of genetic drift and intergenomic exchange on gene transmission rate was discussed. It is suggested that the transgene integrated on a C-chromosome (or better on a cytoplasm genome) is safer than that on an A-chromosome. The transgenic cultivars should be cultivated rotationally by year(s) with other non-transgenic varieties in order to reduce the transfer of the transgene to wild B. rapa species.
Stem Cells, 2008
Embryonic stem cells are unique among cultured cells in their ability to self-renew and different... more Embryonic stem cells are unique among cultured cells in their ability to self-renew and differentiate into a wide diversity of cell types, suggesting that a specific molecular control network underlies these features. Human embryonic stem cells (hESCs) are known to have distinct mRNA expression, global DNA methylation, and chromatin profiles, but the involvement of high-level regulators, such as micro-RNAs (miRNA), in the hESC-specific molecular network is poorly understood. We report that global miRNA expression profiling of hESCs and a variety of stem cell and differentiated cell types using a novel microarray platform revealed a unique set of miRNAs differentially regulated in hESCs, including numerous miRNAs not previously linked to hESCs. These hESC-associated miRNAs were more likely to be located in large genomic clusters, and less likely to be located in introns of coding genes. hESCs had higher expression of oncogenic miRNAs and lower expression of tumor suppressor miRNAs than the other cell types. Many miRNAs upregulated in hESCs share a common consensus seed sequence, suggesting that there is cooperative regulation of a critical set of target miRNAs. We propose that miRNAs are coordinately controlled in hESCs, and are key regulators of pluripotence and differentiation. STEM CELLS
Molecular Breeding, 2005
The high molecular weight (HMW) glutenin subunits, Dtx1.5 + Dty10, are special types of storage p... more The high molecular weight (HMW) glutenin subunits, Dtx1.5 + Dty10, are special types of storage proteins found in Aegilops tauschii that are never found in common wheat (Triticum aestivum). This study reports the characterization of the complete open reading frames (ORFs) of the HMW glutenin genes, Dtx1.5 and Dty10, using a restrict-enzyme based method named the restricted deletion method’ (RDM). The Dtx1.5
Molecular Biology and Evolution, 2007
Expression divergence of duplicate genes is widely believed to be important for their retention a... more Expression divergence of duplicate genes is widely believed to be important for their retention and evolution of new function, although the mechanism that determines their expression divergence remains unclear. We use a genetical genomics approach to explore divergence in genetical control of yeast duplicate genes created by a whole-genome duplication that occurred about 100 MYA and those with a younger duplication age. The analysis reveals that duplicate genes have a significantly higher probability of sharing common genetic control than pairs of singleton genes. The expression quantitative trait loci (eQTLs) have diverged completely for a high proportion of duplicate pairs, whereas a substantially larger proportion of duplicates share common regulatory motifs after 100 Myr of divergent evolution. The similarity in both genetical control and cis motif structure for a duplicate pair is a reflection of its evolutionary age. This study reveals that up to 20% of variation in expression between ancient duplicate gene pairs in the yeast genome can be explained by both cis motif divergence (approximately 8%) and by trans eQTL divergence (approximately 10%). Initially, divergence in all 3 aspects of cis motif structure, trans-genetical control, and expression evolves coordinately with the coding sequence divergence of both young and old duplicate pairs. These findings highlight the importance of divergence in both cis motif structure and trans-genetical control in the diverse set of mechanisms underlying the expression divergence of yeast duplicate genes.
International Immunology, 2003
Bone marrow (BM) chimeras (BMC) generated from mice carrying a null (±/±) mutation in the relB ge... more Bone marrow (BM) chimeras (BMC) generated from mice carrying a null (±/±) mutation in the relB gene of the NF-kB family represent an ideal model for in vivo studies on the role of dendritic cells (DC) in the adaptive immune response. The spleen and lymph nodes (LN) of rel B ±/± BMC contain a small number of residual DC, mainly CD8a + , that fail to up-regulate MHC class II and co-stimulatory molecules after stimulation in vitro. Moreover, residual spleen DC of rel B ±/± BMC have a 4-fold decrease in the ability to uptake and process soluble model antigen, ovalbumin (OVA), and failed to prime CD4 and CD8 T cells in vitro and in vivo. In addition, they also failed to present OVA peptide to OT-II transgenic T lymphocytes at a normal 1:10 (stimulator:responder) cell ratio. In spite of these multiple DC defects, rel B ±/± BMC immunized with plasmid DNA targeted to the spleen as the site of immune induction develop a speci®c CD4 + T cell response comparable to that of rel B competent mice. These data demonstrate that CD4 + T cells can be primed in the absence of functional DC and suggest that rel B may gauge the T cell response in vivo.
Infection and Immunity, 2002
Interleukin-10 (IL-10) is thought to promote intracellular infection, including human visceral le... more Interleukin-10 (IL-10) is thought to promote intracellular infection, including human visceral leishmaniasis, by disabling Th1 cell-type responses and/or deactivating parasitized tissue macrophages. To develop a rationale for IL-10 inhibition as treatment in visceral infection, Th1 cytokine-driven responses were characterized in Leishmania donovani-infected BALB/c mice in which IL-10 was absent or overexpressed or its receptor (IL-10R) was blockaded. IL-10 knockout and normal mice treated prophylactically with anti-IL-10R demonstrated accelerated granuloma assembly and rapid parasite killing without untoward tissue inflammation; IL-12 and gamma interferon mRNA expression, inducible nitric oxide synthase reactivity, and responsiveness to antimony chemotherapy were also enhanced in knockout mice. In IL-10 transgenic mice, parasite replication was unrestrained, and except for antimony responsiveness, measured Th1 cell-dependent events were all initially impaired. Despite subsequent granuloma assembly, high-level infection persisted, and antimony-treated transgenic mice also relapsed. In normal mice with established infection, anti-IL-10R treatment was remarkably active, inducing near-cure by itself and synergism with antimony. IL-10's deactivating effects regulate outcome in experimental visceral leishmaniasis, and IL-10R blockade represents a potential immuno- and/or immunochemotherapeutic approach in this infection.
Fertility and Sterility, 2003
To determine the existence of a soluble signal, secreted from the human blastocyst embryo, that i... more To determine the existence of a soluble signal, secreted from the human blastocyst embryo, that induces HOXA10 gene expression before cell-cell contact. To analyze, by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), cell-free media that had contained human embryos cultured to the blastocyst stage for a soluble molecule that induces HOXA10 expression in an endometrial epithelial cell line (Ishikawa). Assisted reproduction technology program of Yale University, New Haven, Connecticut. Patients undergoing intracytoplasmic sperm injection (ICSI) or in vitro fertilization (IVF) cycles. Treatment of Ishikawa cells with blastocyst-conditioned media. Determination of HOXA10 gene expression. We demonstrate that cell-free media that had contained human embryos cultured to the blastocyst stage contain a soluble molecule that induces HOXA10 expression in an endometrial epithelial cell line (Ishikawa). We found that hCG does not induce HOXA10 in Ishikawa cells. Soluble molecules induce a well-characterized marker of endometrial receptivity in endometrial cells without blastocyst apposition. Additionally, HOXA10 induction can serve as a means of evaluating human embryos cultured for IVF and ET. High quality embryos may induce local endometrial receptivity before trophectoderm-endometrial contact.
Euphytica, 2005
The high molecular weight glutenin subunits (HMW-GS) are important components of storage proteins... more The high molecular weight glutenin subunits (HMW-GS) are important components of storage proteins in common wheat (Triticum aestivum L.). Conventional techniques for identifying the HMW-GS apply SDS-PAGE. To study differentiation of the HMW glutenin genes, partial DNA sequences of the concerned alleles were characterized from eight accessions of hexaploid synthetic wheat and common wheat varieties, and compared with the available sequences. SSR markers based on, and generated from, DNA sequences of the D genome of common wheat and Aegilops tauschii were analyzed to estimate genetic relationships of the accessions. Results showed that the HMW-GS D t x2.1 determined by SDS-PAGE could be identified as two types at the DNA sequence level. One type, designated as D t x2.1a, showed identical SNPs to the D t x1.5 allele and another type, designated as D t x2.1b, had different characteristics. The SSR analysis revealed a relatively close genetic relationship of the two accessions containing the D t x2.1a allele to the accessions containing the D t x1.5 allele. It was concluded that the conventional SDS-PAGE has limitations in determining some HMW-GS, because the minor changes on the DNA sequence of a particular glutenin subunit cannot be detected at protein level, and that the AS-PCR method based on variation of DNA sequences of particular genes will provide a more powerful tool for identifying the HMW-GS. The differentiation of the genes encoding the HMW-GS is probably more rapid than expected. The close relationship between evolutionary changes of the microsatellite DNA and the HMW-GS genes detected in this study needs to be further investigated.
Circulation, 2007
is an important neurotransmitter and hormone. Its role in regulating cardiovascular function at r... more is an important neurotransmitter and hormone. Its role in regulating cardiovascular function at rest and with stress is unclear, however. Methods and Results-An epinephrine-deficient mouse model was generated in which the epinephrine-synthesizing enzyme phenylethanolamine N-methyltransferase was knocked out (KO). Blood pressure and heart rate were monitored by telemetry at rest and during graded treadmill exercise. Cardiac structure and function were evaluated by echocardiography in mice under 1 of 2 conditions: unstressed and lightly anesthetized or restrained and awake. In KO mice, resting cardiovascular function, including blood pressure, heart rate, and cardiac output, was the same as that in wild-type mice, and the basal norepinephrine plasma level was normal. However, inhibition of sympathetic innervation with the ganglion blocker hexamethonium caused a 54% smaller decrease in blood pressure in KO mice, and treadmill exercise caused an 11% higher increase in blood pressure, both suggesting impaired vasodilation in KO mice. Interestingly, phenylethanolamine N-methyltransferase KO did not change the heart rate response to ganglionic blockade and exercise. By echocardiography, KO mice had an increased ratio of left ventricular posterior wall thickness to internal dimensions but did not have cardiac hypertrophy, suggesting concentric remodeling in the KO heart. Finally, in restrained, awake KO mice, heart rate and ejection fraction remained normal, but cardiac output was significantly reduced because of diminished end-diastolic volume. Conclusion-Our data suggest that epinephrine is required for normal blood pressure and cardiac filling responses to stress but is not required for tachycardia during stress or normal cardiovascular function at rest.
Annals of Hematology, 1995
The detection of molecular defects of hemoglobin variants using mutagenically separated polymeras... more The detection of molecular defects of hemoglobin variants using mutagenically separated polymerase chain reaction (MS-PCR) was applied in this study. Using different lengths of allele-specific mutagenic primers, normal and mutant alleles of hemoglobin genes were amplified in the same reaction tube. Subsequent gel electrophoresis showed at least one of the two allelic products at the same loci or at least two of the several allelic products at different loci. We employed MS-PCR to test the following hemoglobin variants: Hb Constant Spring (Hb CS), Hb E, Hb G-Taichung, Hb J-Meinung, and Hb Kaohsiung. The results were the same as those obtained by amplified created reaction sites (ACRS) or direct sequencing. We conclude that the MS-PCR provides a rapid and simple alternative to other techniques for mutation detection in hemoglobin variants. Moreover, the principle can be extended to other genetic diseases.
American Journal of Clinical Pathology, 2009
Neonatal respiratory distress syndrome (RDS) is a disorder of pulmonary immaturity with a high mo... more Neonatal respiratory distress syndrome (RDS) is a disorder of pulmonary immaturity with a high mortality characterized by low levels of pulmonary surfactant. Gestational age determines risk based on concentration of pulmonary surfactant, ie, as gestation progresses the concentration of pulmonary surfactant increases. As a result, newborns delivered at fewer than 28 weeks have a more than 60% risk of RDS, whereas those delivered at more than 34 weeks have a less than 5% risk of RDS. In situations where gestational age alone is not sufficient to determine RDS risk and preterm delivery is medically needed, amniotic fluid analysis can be performed to determine pulmonary surfactant concentration. Four common methods are the lecithin-sphingomyelin ratio, phosphatidylglycerol measurement, surfactant-albumin ratio, and lamellar body count. All of these tests have excellent negative predictive values but poor positive predictive values, ie, they are great at confirming maturity but poor at confirming immaturity.
Heterosis is a biological phenomenon whereby the offspring from two parents show improved and sup... more Heterosis is a biological phenomenon whereby the offspring from two parents show improved and superior performance than either inbred parental lines. Hybrid rice is one of the most successful apotheoses in crops utilizing heterosis. Transcriptional profiling of F 1 super-hybrid rice Liangyou-2186 and its parents by serial analysis of gene expression (SAGE) revealed 1183 differentially expressed genes (DGs), among which DGs were found significantly enriched in pathways such as photosynthesis and carbon-fixation, and most of the key genes involved in the carbon-fixation pathway exhibited up-regulated expression in F 1 hybrid rice. Moreover, increased catabolic activity of corresponding enzymes and photosynthetic efficiency were also detected, which combined to indicate that carbon fixation is enhanced in F 1 hybrid, and might probably be associated with the yield vigor and heterosis in super-hybrid rice. By correlating DGs with yield-related quantitative trait loci (QTL), a potential relationship between differential gene expression and phenotypic changes was also found. In addition, a regulatory network involving circadian-rhythms and light signaling pathways was also found, as previously reported in Arabidopsis, which suggest that such a network might also be related with heterosis in hybrid rice. Altogether, the present study provides another view for understanding the molecular mechanism underlying heterosis in rice.
Nature, 2008
Stem cells are defined as self-renewing cell populations that can differentiate into multiple dis... more Stem cells are defined as self-renewing cell populations that can differentiate into multiple distinct cell types. However, hundreds of different human cell lines from embryonic, fetal, and adult sources have been called stem cells, even though they range from pluripotent cells, typified by embryonic stem cells, which are capable of virtually unlimited proliferation and differentiation, to adult stem cell lines, which can generate a far more limited repertory of differentiated cell types. The rapid increase in reports of new sources of stem cells and their anticipated value to regenerative medicine 1, 2 have highlighted the need for a general, reproducible method for classification of these
Handbook of Obesity Intervention for the Lifespan, 2008
Vaccine, 2001
The fate of T cell responses to peptide-based vaccination is subject to constraints by the major ... more The fate of T cell responses to peptide-based vaccination is subject to constraints by the major histocompatibility complex (MHC), MHC restriction. Using as a model system of T and B cell epitopes from the circumsporozoite protein of Plasmodium falciparum malaria parasite, we show that vaccination by somatic transgene immunization readily primes Balb/c mice (H-2(d)) a strain previously reported to be non-responder to immunization with a synthetic peptide vaccine encompassing these epitopes. Following genetic vaccination Balb/c mice developed a primary T cell response comparable to that of the responder strain C57Bl/6 (H-2(b)). Following booster immunization on day 45 Balb/c mice responded with a typical T cell memory response. Priming induced the formation of specific antibodies, which rose sharply after booster immunization. These findings suggests that genetic immunization can circumvent MHC class II restriction.
TAG Theoretical and Applied Genetics, 2002
Transgenic Brassica napus can be easily crossed with wild Brassica rapa. The spread of the transg... more Transgenic Brassica napus can be easily crossed with wild Brassica rapa. The spread of the transgene to wild species has aroused the general concern about its effect on ecological and agricultural systems. This paper was designated, by means of population genetics, to study the fate of a transgene escape from B. napus to B. rapa. Three models were proposed to survey the change in gene frequency during successive backcross processes by considering selection pressures against aneuploids, against herbicide-susceptible individuals, and by considering A-C intergenomic recombination and the effect of genetic drift. The transmission rate of an A-chromosome gene through an individual to the next generation was 50%, irrespective of the chromosome number; while that of a C-chromosome transgene varied from 8.7% to 39.9%, depending on the chromosome number of the individual used in the backcross. Without spraying herbicide, the frequency of an A-chromosome gene was 50% in the BC 1 generation, and decreased by 50% with the advance of each backcross generation; that of a C-chromosome gene was around 39.9% in BC 1 , 7.7% in BC 2 , 1.2% in BC 3 and 0.1% in the BC 4 generation. Under the selection pressure against herbicide-susceptible individuals, the frequency of a transgene reached a stable value of about 5.5% within six generations of successive backcrossings. The effect of genetic drift and intergenomic exchange on gene transmission rate was discussed. It is suggested that the transgene integrated on a C-chromosome (or better on a cytoplasm genome) is safer than that on an A-chromosome. The transgenic cultivars should be cultivated rotationally by year(s) with other non-transgenic varieties in order to reduce the transfer of the transgene to wild B. rapa species.
Stem Cells, 2008
Embryonic stem cells are unique among cultured cells in their ability to self-renew and different... more Embryonic stem cells are unique among cultured cells in their ability to self-renew and differentiate into a wide diversity of cell types, suggesting that a specific molecular control network underlies these features. Human embryonic stem cells (hESCs) are known to have distinct mRNA expression, global DNA methylation, and chromatin profiles, but the involvement of high-level regulators, such as micro-RNAs (miRNA), in the hESC-specific molecular network is poorly understood. We report that global miRNA expression profiling of hESCs and a variety of stem cell and differentiated cell types using a novel microarray platform revealed a unique set of miRNAs differentially regulated in hESCs, including numerous miRNAs not previously linked to hESCs. These hESC-associated miRNAs were more likely to be located in large genomic clusters, and less likely to be located in introns of coding genes. hESCs had higher expression of oncogenic miRNAs and lower expression of tumor suppressor miRNAs than the other cell types. Many miRNAs upregulated in hESCs share a common consensus seed sequence, suggesting that there is cooperative regulation of a critical set of target miRNAs. We propose that miRNAs are coordinately controlled in hESCs, and are key regulators of pluripotence and differentiation. STEM CELLS
Molecular Breeding, 2005
The high molecular weight (HMW) glutenin subunits, Dtx1.5 + Dty10, are special types of storage p... more The high molecular weight (HMW) glutenin subunits, Dtx1.5 + Dty10, are special types of storage proteins found in Aegilops tauschii that are never found in common wheat (Triticum aestivum). This study reports the characterization of the complete open reading frames (ORFs) of the HMW glutenin genes, Dtx1.5 and Dty10, using a restrict-enzyme based method named the restricted deletion method’ (RDM). The Dtx1.5
Molecular Biology and Evolution, 2007
Expression divergence of duplicate genes is widely believed to be important for their retention a... more Expression divergence of duplicate genes is widely believed to be important for their retention and evolution of new function, although the mechanism that determines their expression divergence remains unclear. We use a genetical genomics approach to explore divergence in genetical control of yeast duplicate genes created by a whole-genome duplication that occurred about 100 MYA and those with a younger duplication age. The analysis reveals that duplicate genes have a significantly higher probability of sharing common genetic control than pairs of singleton genes. The expression quantitative trait loci (eQTLs) have diverged completely for a high proportion of duplicate pairs, whereas a substantially larger proportion of duplicates share common regulatory motifs after 100 Myr of divergent evolution. The similarity in both genetical control and cis motif structure for a duplicate pair is a reflection of its evolutionary age. This study reveals that up to 20% of variation in expression between ancient duplicate gene pairs in the yeast genome can be explained by both cis motif divergence (approximately 8%) and by trans eQTL divergence (approximately 10%). Initially, divergence in all 3 aspects of cis motif structure, trans-genetical control, and expression evolves coordinately with the coding sequence divergence of both young and old duplicate pairs. These findings highlight the importance of divergence in both cis motif structure and trans-genetical control in the diverse set of mechanisms underlying the expression divergence of yeast duplicate genes.
International Immunology, 2003
Bone marrow (BM) chimeras (BMC) generated from mice carrying a null (±/±) mutation in the relB ge... more Bone marrow (BM) chimeras (BMC) generated from mice carrying a null (±/±) mutation in the relB gene of the NF-kB family represent an ideal model for in vivo studies on the role of dendritic cells (DC) in the adaptive immune response. The spleen and lymph nodes (LN) of rel B ±/± BMC contain a small number of residual DC, mainly CD8a + , that fail to up-regulate MHC class II and co-stimulatory molecules after stimulation in vitro. Moreover, residual spleen DC of rel B ±/± BMC have a 4-fold decrease in the ability to uptake and process soluble model antigen, ovalbumin (OVA), and failed to prime CD4 and CD8 T cells in vitro and in vivo. In addition, they also failed to present OVA peptide to OT-II transgenic T lymphocytes at a normal 1:10 (stimulator:responder) cell ratio. In spite of these multiple DC defects, rel B ±/± BMC immunized with plasmid DNA targeted to the spleen as the site of immune induction develop a speci®c CD4 + T cell response comparable to that of rel B competent mice. These data demonstrate that CD4 + T cells can be primed in the absence of functional DC and suggest that rel B may gauge the T cell response in vivo.
Infection and Immunity, 2002
Interleukin-10 (IL-10) is thought to promote intracellular infection, including human visceral le... more Interleukin-10 (IL-10) is thought to promote intracellular infection, including human visceral leishmaniasis, by disabling Th1 cell-type responses and/or deactivating parasitized tissue macrophages. To develop a rationale for IL-10 inhibition as treatment in visceral infection, Th1 cytokine-driven responses were characterized in Leishmania donovani-infected BALB/c mice in which IL-10 was absent or overexpressed or its receptor (IL-10R) was blockaded. IL-10 knockout and normal mice treated prophylactically with anti-IL-10R demonstrated accelerated granuloma assembly and rapid parasite killing without untoward tissue inflammation; IL-12 and gamma interferon mRNA expression, inducible nitric oxide synthase reactivity, and responsiveness to antimony chemotherapy were also enhanced in knockout mice. In IL-10 transgenic mice, parasite replication was unrestrained, and except for antimony responsiveness, measured Th1 cell-dependent events were all initially impaired. Despite subsequent granuloma assembly, high-level infection persisted, and antimony-treated transgenic mice also relapsed. In normal mice with established infection, anti-IL-10R treatment was remarkably active, inducing near-cure by itself and synergism with antimony. IL-10's deactivating effects regulate outcome in experimental visceral leishmaniasis, and IL-10R blockade represents a potential immuno- and/or immunochemotherapeutic approach in this infection.
Fertility and Sterility, 2003
To determine the existence of a soluble signal, secreted from the human blastocyst embryo, that i... more To determine the existence of a soluble signal, secreted from the human blastocyst embryo, that induces HOXA10 gene expression before cell-cell contact. To analyze, by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), cell-free media that had contained human embryos cultured to the blastocyst stage for a soluble molecule that induces HOXA10 expression in an endometrial epithelial cell line (Ishikawa). Assisted reproduction technology program of Yale University, New Haven, Connecticut. Patients undergoing intracytoplasmic sperm injection (ICSI) or in vitro fertilization (IVF) cycles. Treatment of Ishikawa cells with blastocyst-conditioned media. Determination of HOXA10 gene expression. We demonstrate that cell-free media that had contained human embryos cultured to the blastocyst stage contain a soluble molecule that induces HOXA10 expression in an endometrial epithelial cell line (Ishikawa). We found that hCG does not induce HOXA10 in Ishikawa cells. Soluble molecules induce a well-characterized marker of endometrial receptivity in endometrial cells without blastocyst apposition. Additionally, HOXA10 induction can serve as a means of evaluating human embryos cultured for IVF and ET. High quality embryos may induce local endometrial receptivity before trophectoderm-endometrial contact.
Euphytica, 2005
The high molecular weight glutenin subunits (HMW-GS) are important components of storage proteins... more The high molecular weight glutenin subunits (HMW-GS) are important components of storage proteins in common wheat (Triticum aestivum L.). Conventional techniques for identifying the HMW-GS apply SDS-PAGE. To study differentiation of the HMW glutenin genes, partial DNA sequences of the concerned alleles were characterized from eight accessions of hexaploid synthetic wheat and common wheat varieties, and compared with the available sequences. SSR markers based on, and generated from, DNA sequences of the D genome of common wheat and Aegilops tauschii were analyzed to estimate genetic relationships of the accessions. Results showed that the HMW-GS D t x2.1 determined by SDS-PAGE could be identified as two types at the DNA sequence level. One type, designated as D t x2.1a, showed identical SNPs to the D t x1.5 allele and another type, designated as D t x2.1b, had different characteristics. The SSR analysis revealed a relatively close genetic relationship of the two accessions containing the D t x2.1a allele to the accessions containing the D t x1.5 allele. It was concluded that the conventional SDS-PAGE has limitations in determining some HMW-GS, because the minor changes on the DNA sequence of a particular glutenin subunit cannot be detected at protein level, and that the AS-PCR method based on variation of DNA sequences of particular genes will provide a more powerful tool for identifying the HMW-GS. The differentiation of the genes encoding the HMW-GS is probably more rapid than expected. The close relationship between evolutionary changes of the microsatellite DNA and the HMW-GS genes detected in this study needs to be further investigated.
Circulation, 2007
is an important neurotransmitter and hormone. Its role in regulating cardiovascular function at r... more is an important neurotransmitter and hormone. Its role in regulating cardiovascular function at rest and with stress is unclear, however. Methods and Results-An epinephrine-deficient mouse model was generated in which the epinephrine-synthesizing enzyme phenylethanolamine N-methyltransferase was knocked out (KO). Blood pressure and heart rate were monitored by telemetry at rest and during graded treadmill exercise. Cardiac structure and function were evaluated by echocardiography in mice under 1 of 2 conditions: unstressed and lightly anesthetized or restrained and awake. In KO mice, resting cardiovascular function, including blood pressure, heart rate, and cardiac output, was the same as that in wild-type mice, and the basal norepinephrine plasma level was normal. However, inhibition of sympathetic innervation with the ganglion blocker hexamethonium caused a 54% smaller decrease in blood pressure in KO mice, and treadmill exercise caused an 11% higher increase in blood pressure, both suggesting impaired vasodilation in KO mice. Interestingly, phenylethanolamine N-methyltransferase KO did not change the heart rate response to ganglionic blockade and exercise. By echocardiography, KO mice had an increased ratio of left ventricular posterior wall thickness to internal dimensions but did not have cardiac hypertrophy, suggesting concentric remodeling in the KO heart. Finally, in restrained, awake KO mice, heart rate and ejection fraction remained normal, but cardiac output was significantly reduced because of diminished end-diastolic volume. Conclusion-Our data suggest that epinephrine is required for normal blood pressure and cardiac filling responses to stress but is not required for tachycardia during stress or normal cardiovascular function at rest.
Annals of Hematology, 1995
The detection of molecular defects of hemoglobin variants using mutagenically separated polymeras... more The detection of molecular defects of hemoglobin variants using mutagenically separated polymerase chain reaction (MS-PCR) was applied in this study. Using different lengths of allele-specific mutagenic primers, normal and mutant alleles of hemoglobin genes were amplified in the same reaction tube. Subsequent gel electrophoresis showed at least one of the two allelic products at the same loci or at least two of the several allelic products at different loci. We employed MS-PCR to test the following hemoglobin variants: Hb Constant Spring (Hb CS), Hb E, Hb G-Taichung, Hb J-Meinung, and Hb Kaohsiung. The results were the same as those obtained by amplified created reaction sites (ACRS) or direct sequencing. We conclude that the MS-PCR provides a rapid and simple alternative to other techniques for mutation detection in hemoglobin variants. Moreover, the principle can be extended to other genetic diseases.
American Journal of Clinical Pathology, 2009
Neonatal respiratory distress syndrome (RDS) is a disorder of pulmonary immaturity with a high mo... more Neonatal respiratory distress syndrome (RDS) is a disorder of pulmonary immaturity with a high mortality characterized by low levels of pulmonary surfactant. Gestational age determines risk based on concentration of pulmonary surfactant, ie, as gestation progresses the concentration of pulmonary surfactant increases. As a result, newborns delivered at fewer than 28 weeks have a more than 60% risk of RDS, whereas those delivered at more than 34 weeks have a less than 5% risk of RDS. In situations where gestational age alone is not sufficient to determine RDS risk and preterm delivery is medically needed, amniotic fluid analysis can be performed to determine pulmonary surfactant concentration. Four common methods are the lecithin-sphingomyelin ratio, phosphatidylglycerol measurement, surfactant-albumin ratio, and lamellar body count. All of these tests have excellent negative predictive values but poor positive predictive values, ie, they are great at confirming maturity but poor at confirming immaturity.
Heterosis is a biological phenomenon whereby the offspring from two parents show improved and sup... more Heterosis is a biological phenomenon whereby the offspring from two parents show improved and superior performance than either inbred parental lines. Hybrid rice is one of the most successful apotheoses in crops utilizing heterosis. Transcriptional profiling of F 1 super-hybrid rice Liangyou-2186 and its parents by serial analysis of gene expression (SAGE) revealed 1183 differentially expressed genes (DGs), among which DGs were found significantly enriched in pathways such as photosynthesis and carbon-fixation, and most of the key genes involved in the carbon-fixation pathway exhibited up-regulated expression in F 1 hybrid rice. Moreover, increased catabolic activity of corresponding enzymes and photosynthetic efficiency were also detected, which combined to indicate that carbon fixation is enhanced in F 1 hybrid, and might probably be associated with the yield vigor and heterosis in super-hybrid rice. By correlating DGs with yield-related quantitative trait loci (QTL), a potential relationship between differential gene expression and phenotypic changes was also found. In addition, a regulatory network involving circadian-rhythms and light signaling pathways was also found, as previously reported in Arabidopsis, which suggest that such a network might also be related with heterosis in hybrid rice. Altogether, the present study provides another view for understanding the molecular mechanism underlying heterosis in rice.
Nature, 2008
Stem cells are defined as self-renewing cell populations that can differentiate into multiple dis... more Stem cells are defined as self-renewing cell populations that can differentiate into multiple distinct cell types. However, hundreds of different human cell lines from embryonic, fetal, and adult sources have been called stem cells, even though they range from pluripotent cells, typified by embryonic stem cells, which are capable of virtually unlimited proliferation and differentiation, to adult stem cell lines, which can generate a far more limited repertory of differentiated cell types. The rapid increase in reports of new sources of stem cells and their anticipated value to regenerative medicine 1, 2 have highlighted the need for a general, reproducible method for classification of these