Biomedical subjects

Hao Yu

Publications and source records attributed to Hao Yu.

At least 37 records · Page 2Linked to original sources

PubMed2006

[A new method for medial canthoplasty combined double eyelid formation].

OBJECTIVE: In order to explore a new method to perform the medial canthoplasty applied with upper eyelid fold formation in a single procedure. METHODS: According to the principles to correct the deformity of the medial canthus, a new method was designed to fetch up the skin defect of the medial side of upper eyelid, minimize the skin scarring around the medial canthus, and form upper eyelid fold. RESULTS: The 86 cases, which mild or moderate epicanthus without upper eyelid fold, were treated with this technique and long-term follow-ups above 6 months were made. The 67 cases were given the follow-ups. The appearances of upper eyelid fold and medial canthus were evaluated. The appearances of eyelid fold were paralleled type. The epicanthus was corrected completely or in major. CONCLUSIONS: This new canthoplastic method with upper eyelid fold formation may be suitable to all the medial epicanthus except inverse epicanthus. All of the patients were satisfied with the final results.

Adolescent↗

PubMed2006

[Estimation on gene-environment interaction in the partial case-control study].

OBJECTIVE: To introduce the approaches for estimating gene-environment interaction based on partial case-control studies. METHODS: The effects of logistic model and log-linear model for estimating the main effects and gene-environment interaction effect were estimated by means of maximum likelihood methods in traditional case-control studies, case-only studies and partial case-control studies, respectively. An example was also illustrated. RESULTS: In traditional case-control study with complete data, the results of logistic model and log-linear model were equivalent. In case-only study without any information about controls, the logistic model can also efficiently estimate gene-environment interaction. In partial case-control study, environmental information was collected from all of the cases and controls, while genetic information was only collected from cases. For this case-control study with incomplete data, a suitable parameterized log-linear model could simultaneously and efficiently estimate the main effect of environment and gene-environment interaction, whereas the logistic model could not. CONCLUSION: For a partial case-control study, log-linear model could estimate not only the main effect of environment but also gene-environment interaction. If genotype and exposure were independent, estimators from partial case-control were as precisely as those from complete-data case-control studies.

Case-Control Studies↗

PubMed2006

[Introduction on "case-sibling control design"].

OBJECTIVE: To introduce the design and statistical methods of case-sibling control design and to analyze the published data. METHODS: Data from an association study between the coronary heart disease and methylenetetrahydrofolate reductase gene C677T polymorphism was analyzed by the sib transmission/disequibrium test (s-TDT) and the sibship disequilibrium (SDT) methods. RESULTS: Using s-TDT method, Z value was 0.27 with P > 0.05. The result of SDT method showed that chi-square was 0.31 with 1 df, P > 0.05. All results suggested that neither s-TDT nor SDT showed significant difference between the transmitted and untransmitted methylenetetrahydrofolate reductase gene C677T allele distributions. CONCLUSION: Case-sibling control design might avoid population stratification by using siblings as controls thus might be used to test association and linkage between genes and disease.

Case-Control Studies↗

PubMed2006

Uninsurance among children eligible for the State Children's Health Insurance Program: results from a national survey.

Uninsurance among State Children's Health Insurance Program (SCHIP)--eligible children was examined using the 2001 National Survey of Children with Special Health Care Needs. Nationally, 6.1% of children (4.3 million) were eligible for SCHIP in 2000, and 35.6% (1.5 million) eligible children were uninsured. In addition to the variation across states in SCHIP eligibility and uninsurance, the study revealed a lower uninsurance rate in the 17 states that expanded Medicaid eligibility, compared with the 34 states with separate SCHIP programs that were implemented alone or in combination with Medicaid expansion. It was also revealed that the parents of SCHIP-eligible but uninsured children had limited knowledge of and experience with SCHIP.

Adolescent↗

PubMed2006

[Foscarnet sodium for treatment in patients with severe chronic hepatitis B].

OBJECTIVE: To investigate the effectiveness of foscarnet sodium in the treatment of severe chronic hepatitis B. METHODS: Two hundred and eight patients were enrolled in a multicenter, double-blind, controlled study. The patients received foscarnet sodium (foscarnet group) or saline (control group) injections for 4 weeks, and were then followed for 24 weeks. RESULTS: HBV DNA negative rate was 12.8% in the foscarnet group and 7.1% in the control group at the end of treatment; and it was 5.5% and 3.0% at the end of the follow-up period respectively (P > 0.05). The rate of HBV DNA decrease of more than 2 log copies/ml was 53.2% in the foscarnet group and 16.2% in the control group at the end of treatment, and 23.9% and 8.1% (P < 0.01) respectively at the end of the follow-up period. The rate of HBV DNA < 10(5) copies/ml was 64.2% and 30.3% at week 4 in the two groups respectively, and 40.4% and 22.2% (P < 0.01) at the end of the follow-up period. HBeAg negative rate was 17.3% and 5.8% at the end of the treatment, and 22% and 5.4% at the end of the follow-up period (P < 0.01). The rate of HBeAg seroconversion was 12.7% and 3.7% at week 4, and 16.7% and 1.5% at the end of the follow-up period. Response rate was 60.6% and 21.2% at the end of week 4 (P < 0.05). CONCLUSION: Foscarnet sodium injection has a good effect on severe chronic hepatitis B patients and it is safe to use on them.

Adolescent↗

PubMed2005

Solid phase microextraction for analysis of alkanes and aromatic hydrocarbons in human breath.

In this work, solid phase microextraction-gas chromatograph (SPME-GC) was applied to analyze alkanes and aromatic hydrocarbons in human breath, providing a potential non-invasive method to screen lung cancer. This method has been optimized and evaluated. It provided quantification limits ranging from 0.04 to 4.2 ng/mL, linear correlations ranging from 0.9845 to 0.9966 and R.S.D. values less than 9.8%. Total 30 breath samples, from 15 lung cancer patients and 15 healthy persons, were analyzed, and the alkanes and aromatic hydrocarbons were detected in 73.3% lung cancer patients and in 13.3% healthy persons by this method. Above all, It was demonstrated that this SPME-GC method provided a sensitive and non-invasive measure means to analyze alkanes and aromatic hydrocarbons in human breath, and brought forward a potential application for screening lung cancer.

Aged↗

PubMed2005

Folding of the SARS coronavirus spike glycoprotein immunological fragment (SARS_S1b): thermodynamic and kinetic investigation correlating with three-dimensional structural modeling.

Spike glycoprotein of SARS coronavirus (S protein) plays a pivotal role in SARS coronavirus (SARS_CoV) infection. The immunological fragment of the S protein (Ala251-His641, SARS_S1b) is believed to be essential for SARS_CoV entering the host cell through S protein-ACE-2 interaction. We have quantitatively characterized the thermally induced and GuHCl-induced unfolding features of SARS_S1b using circular dichroism (CD), tryptophan fluorescence, and stopped-flow spectral techniques. For the thermally induced unfolding at pH 7.4, the apparent activation energy (E(app)) and transition midpoint temperature (Tm) were determined to be 16.3 +/- 0.2 kcal/mol and 52.5 +/- 0.4 degrees C, respectively. The CD spectra are not dependent on temperature, suggesting that the secondary structure of SARS_S1b has a relatively high thermal stability. GuHCl strongly affected SARS_S1b structure. Both the CD and fluorescent spectra resulted in consistent values of the transition middle concentration of the denaturant (Cm, ranging from 2.30 to 2.45 M) and the standard free energy change (deltaG(o), ranging from 2.1 to 2.5 kcal/mol) for the SARS_S1b unfolding reaction. Moreover, the kinetic features of the chemical unfolding and refolding of SARS_S1b were also characterized using a stopped-flow CD spectral technique. The obvious unfolding reaction rates and relaxation times were determined at various GuHCl concentrations, and the Cm value was obtained, which is very close to the data that resulted from CD and fluorescent spectral determinations. Secondary and three-dimensional structural predictions by homology modeling indicated that SARS_S1b folded as a globular-like structure by beta-sheets and loops; two of the four tryptophans are located on the protein surface, which is in agreement with the tryptophan fluorescence result. The three-dimensional model was also used to explain the recently published experimental results of S1-ACE-2 binding and immunizations.

Amino Acid Sequence↗

PubMed2005

Cloning and preliminary characterization of lh3 gene encoding a putative acetyltransferase from a rifamycin SV-producing strain Amycolatopsis mediterranei.

An ORF located immediately downstream of glnR gene was cloned from Amycolatopsis mediterranei U32 and was named lh3. Sequence analysis revealed that lh3 encodes a putative acetyltransferase, which shows high amino acid sequence similarities to the mycothiol synthase (MshD) from other actinomycetes. For functional analysis, mutation in lh3 gene was generated by gene replacement with an apramycin resistance gene through homologous recombination. Compared with the wild type strain, the resulting mutant was more sensitive to H2O2, apramycin and erythromycin by two- to three-fold. These results suggest that the lh3 gene plays an important role in the course of detoxification in A. mediterranei U32.

Acetyltransferases↗

PubMed2005

The cross talk between protein kinase A- and RhoA-mediated signaling in cancer cells.

The cross talk between cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) and RhoA-mediated signal transductions and the effect of this cross talk on biologic features of human prostate and gastric cancer cells were investigated. In the human gastric cancer cell line, SGC-7901, lysophosphatidic acid (LPA) increased RhoA activity in a dose-dependent manner. The cellular permeable cAMP analog, 8-chlorophenylthio-cAMP (CPT-cAMP), inhibited the LPA-induced RhoA activation and caused phosphorylation of RhoA at serine(188). Immunofluorescence microscopy, Western blotting, and green fluorescent protein (GFP)-tagged RhoA location assay in live cells revealed that RhoA was distributed in both the cytoplasm and nucleus of SGC-7901 cells. Treatment with LPA and/or CPT-cAMP did not induce obvious translocation of RhoA in the cells. The LPA treatment caused formation of F-actin in SGC-7901 cells, and CPT-cAMP inhibited the formation. In a modified Boyden chamber assay, LPA stimulated the migration of SGC-7901 cells, and CPT-cAMP dose-dependently inhibited the stimulating effect of LPA. In soft agar assay, LPA stimulated early proliferation of SGC-7901 cells, and CPT-cAMP significantly inhibited the growth of LPA-stimulated cells. In the prostate cancer cell line, PC-3, LPA caused morphologic changes from polygonal to round, and transfection with plasmid DNA encoding constitutively active RhoA(63L) caused a similar change. Treatment with CPT-cAMP inhibited the changes in both cases. However, in PC-3 cells transfected with a plasmid encoding mutant RhoA188A, LPA induced rounding, but CPT-cAMP could not prevent the change. Results of this experiment indicated that cAMP/PKA inhibited RhoA activation, and serine188 phosphorylation on RhoA was necessary for PKA to exert its inhibitory effect on RhoA activation. The cross talk between cAMP/PKA and RhoA-mediated signal transductions had significant affect on biologic features of gastric and prostate cancer cells, such as morphologic and cytoskeletal change, migration, and anchorage-independent growth. The results may be helpful in implementing novel therapeutic strategies for invasive and metastatic prostate and gastric cancers.

Apoptosis Regulatory Proteins↗

PubMed2005

[Molecular characteristics of DNA-A of tomato leaf curl Guangdong virus isolate G2].

Virus isolate G2 was isolated from tomato plants showing leaf curl symptoms in Guangdong. The complete nucleotide sequence of G2 DNA-A was determined to be 2744 nucleotides encoding six potential ORFs, with two (AV1 and AV2) in virus sense and four (AC1, AC2, AC3 and AC4) in complementary sense. G2 DNA-A has a typical characteristics of Begomovirus genome organization. BLAST results showed that G2 DNA-A belonged to the Begomovirus of Geminiviridae. Pairwise comparisons of G2 DNA-A with those of other 41 begomoviruses indicated that G2 DNA-A was most closely related to that of Papaya leaf curl China virus isolate G10 (PaLCuCNV-[G10]) (82.8% sequence identity). The intergenic region (IR) of G2 differed to great extent with other begomoviruses (30.9%-81.8% nucleotide sequence identity); when individual encoded proteins were compared, the CP of G2 had relatively high amino acid sequence identity (77.6%-99.2%) with other begomoviruses whereas the AC4 of G2 had less amino acid sequence identity (43.5%-78.8%). Phylogenetic analysis based on the DNA-A sequences also showed that G2 was less related to the reported begomoviruses. These results revealed that G2 infecting Guangdong tomato might be a previously unreported species of Begomovirus, for which the name Tomato leaf curl Guangdong Virus (ToLCGDV) is proposed.

Amino Acid Sequence↗

PubMed2005

[Effect of RhoA and cAMP on morphological changes in human prostate cancer cell line PC-3].

This paper was designed to investigate the effect of RhoA and cAMP/PKA mediating signal transduction on the morphological changes of human prostate cancer cell line PC-3. Different RhoA cDNA expressing constructs were used to transfect PC-3 cells. Transfected and untransfected cells were stimulated with lysophosphatidic acid(LPA) and/or cAMP. The morphological changes of the cells were recorded by inversive microscope. Results showed that the untransfected cells changed their conformation from polygonal to round with the stimulation of LPA,while cAMP prevented the change. LPA caused the same change in cells transfected with wild type, constitutively active type and 188 mutant of RhoA. cAMP prevented the change in cells transfected with wild type and constitutively active RhoA but not in cells transfected with 188 mutant of RhoA. The results suggested that cAMP/PKA could inhibit the morphological effect of RhoA through phosphorylating RhoA on 188 serine.

Cell Line, Tumor↗

PubMed2005

[An epidemiological study on vaccine derived polio virus circle in Zhenfeng County of Guizhou Province].

OBJECTIVE: To analyze the event and cause of vaccine derived polio virus (VDPV) circle happened at Yaoshang Village, Wanlan Township, Zhenfeng County, Qianxinan Prefecture, Guizhou Province in August 2004. METHODS: Virus isolation was performed for stool specimens collected from two children cases with acute flaccid paralysis (AFP) reported at Yaoshang Village and 21 normal children under five years old in the same village. And, routine immunization coverage at the Village and AFP incidence and performance of AFP surveillance system in Zhenfeng County were investigated, as well. RESULTS: Vaccine derived polio virus 1 (VDPV1) was identified in the feces of two affected children at Yaoshang Village and three other normal children at the same village. Totally, seven cases of AFP have been underreported in Zhenfeng County since 2002. Routine immunization coverage was rather low at Wanlan Township, and nearly nil at Yaoshang Village. CONCLUSIONS: Oral polio vaccine (OPV) with attenuated live virus has been used in China for many years to prevent polio. Circulation of VDPV in Zhenfeng County issues a new challenge to eradication of polio. It is necessary to strengthen routine immunization and AFP surveillance to prevent occurrence of VDPV event.

Child, Preschool↗

PubMed2005

[Study on an epidemic caused by the vaccine-derived poliovirus circulation in Guizhou province, 2004].

OBJECTIVE: To study the circulating vaccine-derived poliovirus (cVDPVs) that occurred in Zhenfeng county, Guizhou province in 2004 and to discover wild-poliovirus, vaccine-derived poliovirus (VDPVs) and other vaccine-associated poliovirus which could cause clinical poliomyelitis. METHODS: Field epidemiological studies at the epidemic area and collecting acute flaccid paralysis (AFP) case and contact stool specimen for virus identification and nucleotide sequencing. Analysis on data related to annual reports on stool specimens surveillance which involved AFP case and contacts in the resent years in Zhenfeng county. RESULTS: Type-I VDPVs had been isolated from 2 AFP cases and 3 contact stool specimen in Wanlan village of Zhenfeng. After the first cVDPVs case was identified, there were 3 cases identified of having other vaccine-associated poliovirus of type-I or type-II in the 5 case of AFP that met the criteria of clinical poliomyelitis. The result of virological surveillance on polio showed that the EV isolation rate (55.1%) of Zhenfeng county was higher than the rate from the whole province of the same year (23.2%). The poliovirus (PV) isolation rate (36.8%) was obviously higher in 2004 than in the previous years. In the 16 PVs strains, the type-I accounted for 43.8% which was significantly higher than the average level (18.3%) from the whole province. CONCLUSIONS: Data indicated that the type-I VDPVs had been circulating (cVDPVs) in Zhenfeng county in Guizhou province. Clinical poliomyelitis was caused by non-VDPVs. The increased PV infection and the decreasing rate of vaccination in the general population were responsible for the epidemic of type-I cVDPVs at this time. Monitoring and evaluation on the rate of routine immunization program and prediction of the trend of epidemic should be strenthened.

Adolescent↗

PubMed2004

Laminin isoforms differentially regulate adhesion, spreading, proliferation, and ERK activation of beta1 integrin-null cells.

The presence of many laminin receptors of the beta1 integrin family on most cells makes it difficult to define the biological functions of other major laminin receptors such as integrin alpha6beta4 and dystroglycan. We therefore tested the binding of a beta1 integrin-null cell line GD25 to four different laminin variants. The cells were shown to produce dystroglycan, which based on affinity chromatography bound to laminin-1, -2/4, and -10/11, but not to laminin-5. The cells also expressed the integrin alpha6Abeta4A variant. GD25 beta1 integrin-null cells are known to bind poorly to laminin-1, but we demonstrate here that these cells bind avidly to laminin-2/4, -5, and -10/11. The initial binding at 20 min to each of these laminins could be inhibited by an integrin alpha6 antibody, but not by a dystroglycan antibody. Hence, integrin alpha6Abeta4A of GD25 cells was identified as a major receptor for initial GD25 cell adhesion to three out of four tested laminin isoforms. Remarkably, cell adhesion to laminin-5 failed to promote cell spreading, proliferation, and extracellular signal-regulated kinase (ERK) activation, whereas all these responses occurred in response to adhesion to laminin-2/4 or -10/11. The data establish GD25 cells as useful tools to define the role integrin alpha6Abeta4A and suggest that laminin isoforms have distinctly different capacities to promote cell adhesion and signaling via integrin alpha6Abeta4A.

Animals↗

PubMed2004

HANABA TARANU is a GATA transcription factor that regulates shoot apical meristem and flower development in Arabidopsis.

We have isolated a new mutant, hanaba taranu (han), which affects both flower and shoot apical meristem (SAM) development in Arabidopsis thaliana. Mutants have fused sepals and reduced organ numbers in all four whorls, especially in the 2nd (petal) and 3rd (stamen) whorls. han meristems can become flatter or smaller than in the wild type. HAN encodes a GATA-3-like transcription factor with a single zinc finger domain. HAN is transcribed at the boundaries between the meristem and its newly initiated organ primordia and at the boundaries between different floral whorls. It is also expressed in vascular tissues, developing ovules and stamens, and in the embryo. han interacts strongly with clavata (clv) mutations (clv1, clv2, and clv3), resulting in highly fasciated SAMs, and we find that WUS expression is altered in han mutants from early embryogenesis. In addition, HAN is ectopically expressed both in clv1 and clv3 mutants. We propose that HAN is normally required for establishing organ boundaries in shoots and flowers and for controlling the number and position of WUS-expressing cells. Ectopic HAN expression causes growth retardation, aberrant cell division patterns, and loss of meristem activity, suggesting that HAN is involved in controlling cell proliferation and differentiation.

Amino Acid Sequence↗

PubMed2004

The homeotic protein AGAMOUS controls microsporogenesis by regulation of SPOROCYTELESS.

The Arabidopsis homeotic gene AGAMOUS (AG) is necessary for the specification of reproductive organs (stamens and carpels) during the early steps of flower development. AG encodes a transcription factor of the MADS-box family that is expressed in stamen and carpel primordia. At later stages of development, AG is expressed in distinct regions of the reproductive organs. This suggests that AG might function during the maturation of stamens and carpels, as well as in their early development. However, the developmental processes that AG might control during organogenesis and the genes that are regulated by this factor are largely unknown. Here we show that microsporogenesis, the process leading to pollen formation, is induced by AG through activation of the SPOROCYTELESS gene (SPL, also known as NOZZLE,NZZ), a regulator of sporogenesis. Furthermore, we demonstrate that SPL can induce microsporogenesis in the absence of AG function, suggesting that AG controls a specific process during organogenesis by activating another regulator that performs a subset of its functions.

AGAMOUS Protein, Arabidopsis↗

PubMed2004

Floral homeotic genes are targets of gibberellin signaling in flower development.

Gibberellins (GAs) are a class of plant hormones involved in the regulation of flower development in Arabidopsis. The GA-deficient ga1-3 mutant shows retarded growth of all floral organs, especially abortive stamen development that results in complete male sterility. Until now, it has not been clear how GA regulates the late-stage development of floral organs after the establishment of their identities within floral meristems. Various combinations of null mutations of DELLA proteins can gradually rescue floral defects in ga1-3. In particular, the synergistic effect of rga-t2 and rgl2-1 can substantially restore flower development in ga1-3. We find that the transcript levels of floral homeotic genes APETALA3 (AP3), PISTILLATA (PI), and AGAMOUS (AG) are immediately upregulated in young flowers of ga1-3 upon GA treatment. Using a steroid-inducible activation of RGA, we further demonstrated that these floral homeotic genes are transcriptionally repressed by RGA activity in young flowers whereas the expression of LEAFY (LFY) and APETALA1 (AP1) is not substantially affected. In addition, we observed the partial rescue of floral defects in ga1-3 by overexpression of AG. Our results indicate that GA promotes the expression of floral homeotic genes by antagonizing the effects of DELLA proteins, thereby allowing continued flower development.

Arabidopsis↗

PubMed2004

Repression of AGAMOUS-LIKE 24 is a crucial step in promoting flower development.

Flower development begins as floral meristems arise in succession on the flank of the inflorescence meristem. Floral meristem identity genes LEAFY (LFY) and APETALA1 (AP1) promote establishment and maintenance of floral identity in newly formed floral primordia. Without their activity, the floral primordia develop with inflorescence characteristics. The underlying molecular-genetic mechanism is unknown. Here we show that these phenotypes are due in large part to the ectopic expression of AGAMOUS-LIKE 24 (AGL24), a central regulator of floral meristem identity. We present evidence that AGL24 is an early target of transcriptional repression by LFY and AP1. Without such repression, continued AGL24 expression in floral meristems is sufficient to cause floral reversion regardless of the activation of floral organ identity genes. This indicates that LFY and AP1 promote floral development not only by positively regulating genes activated in flower development, but also by repressing AGL24, a promoter of inflorescence fate.

Arabidopsis↗