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Biomedical subjects

Y L Zheng

Publications and source records attributed to Y L Zheng.

At least 19 recordsLinked to original sources
PubMed2006

AFLP and PCR-based markers linked to Rf3, a fertility restorer gene for S cytoplasmic male sterility in maize.

The Rf3 gene restores the pollen fertility disturbed by S male sterile cytoplasm. In order to develop molecular markers tightly linked to Rf3, we used amplified fragment length polymorphism (AFLP) technique with near isogenic lines (NILs) and bulk segregant analysis (BSA). A BC(1)F(1) population from a pair of NILs with different Rf3 locus was constructed and 528 primer combinations was screened. A linkage map was constructed around the Rf3 locus, which was mapped on the distal region of chromosome 2 long arm with the help of SSR marker UMC2184. The closest marker E7P6 was 0.9 cM away from Rf3. Marker E3P1, 2.4 cM from Rf3, and E12M7, 1.8 cM from Rf3, were converted into a codominant CAPS and a dominant SCAR marker, and designated as CAPSE3P1 and SCARE12M7, respectively. These markers are useful for marker-assisted selection and map-based cloning of the Rf3 gene.

Chromosome Mapping↗
PubMed2006

Genetic diversity of Triticum turgidum L. based on microsatellite markers.

Using microsatellite (SSR) markers, the genetic diversity and genetic relationships among 48 Triticum turgidum L. accessions, including 30 Triticum turgidum L. ssp. turgidum, 7 Triticum turgidum L. ssp. durum, 4 Triticum turgidum L. ssp. carthlicum, 3 Triticum turgidum L. ssp. paleocolchicum, 2 Triticum turgidum L. ssp. turanicum and 2 Triticum turgidum L. ssp. polonicum accessions, were investigated. A total of 97 alleles were detected on 16 SSR loci. At each locus, the number of alleles ranged from 2 to 14, with an average of 6.1. The Genetic similarity (GS) value ranged from 0.20 to 0.92, with the mean of 0.59. In cluster analysis, it was found the 48 Triticum turgidum L. accessions could be distinguished easily by SSR markers, whereas the 6 subspecies taxonomic entities of T. turgidum L. could not differentiate with each other, indicating that the morphological differences present among the 6 subspecies could not be reflected by the SSR markers. These results suggested that SSR markers had the superiority in detecting the genetic diversity of T. turgidum L., while it was not good for the studies of the phylogenic relationships among the subspecies of T. turgidum L.

Genetic Variation↗
PubMed2005

Identification of LMW glutenin-like genes from Secale sylvestre host.

Three low-molecular-weight (LMW) glutenin-like genes (designated as Ssy1, Ssy2 and Ssy3) from Secale sylvestre Host were isolated and characterized. The three genes consist of a predicted highly conservative signal peptide with 20 amino acids, a short N-terminal region with 13 amino acids, a highly variable repetitive domain and a less variable C-terminal domain. The deduced amino acid sequences of the three genes were the LMW-m type due to a methionine residue at the N-terminus. The phylogenic analysis indicated that the prolamin genes could be perfectly clustered into five groups, including HMW-GS, LMW-GS, alpha/beta-, gamma- and omega-prolamin. The LMW glutenin-like genes of S. sylvestre were more orthologous with the LMW-GS genes of wheat and B hordein genes of barley, which also had been confirmed by the homology analysis with the LMW-GS of wheat at Glu-A3, Glu-B3 and Glu-D3 loci. These results indicated that a chromosome locus (designated as Glu-R3) might be located on the R genome of S. sylvestre with the functions similar to the Glu-3 locus in wheat and its related species.

Amino Acid Sequence↗
PubMed2002

A family-based and case-control association study of the NOTCH4 gene and schizophrenia.

Recently a strong positive association between schizophrenia and Notch4 has been reported. Both individual markers and haplotypes showed association with the disease, with five markers (three microsatellites and two SNPs) being tested. In order to test this finding we genotyped these markers in the Han Chinese population using a sample of 544 cases and 621 controls as well as >300 trios. Analysis of allele, genotype and haplotype frequencies in both samples showed no association between the markers and the disease. Our results would indicate that a significant role for the Notch4 gene in schizophrenia can be ruled out in the Han Chinese. However, similar studies are necessary in the Caucasian population as linkage disequilibrium arrangements and founder effects may differ between these two populations.

Adolescent↗
PubMed2001

Tryptophan hydroxylase gene variant and smoking behavior.

Approximately 50% of the variance in smoking behavior is attributable to genetic factors. Genes in the serotonin system are plausible candidates because of serotonin's role in mood regulation. The present study examined the association of smoking behavior with a polymorphism in the TPH gene, which codes for a rate limiting enzyme in the biosynthesis of serotonin. A polymorphism in intron 7 has been linked with a variety of traits involving poor impulse control. Participants in this study were 249 Caucasian smokers and 202 nonsmokers recruited through newspaper advertisements. Smokers completed smoking history and nicotine dependence assessments. The overall frequencies of the A- and C-allele were 42% and 58%, respectively. There was no association of TPH alleles with smoking status. However, case series analysis indicated that individuals with the A/A genotype started smoking at age 15.6 years, compared with 17.3 years among smokers with other genotypes. This association was significant in a multivariate regression model controlling for age, education, body mass index (BMI), alcohol use, and medication use. This finding is consistent with previous studies relating the A-allele to impulsive behavior and suggests that it may predispose to early smoking initiation. Future family-based studies are needed to confirm this finding. Published 2001 Wiley-Liss, Inc.

Adult↗
PubMed2001

High-density allelotype of the commonly studied gastric cancer cell lines.

Gastric cancer is one of the leading causes of death from cancer throughout the world, and studies to elucidate the genetic defects found in this type of cancer are growing in number. Increasingly sophisticated techniques and the sequencing of the human genome have had an impact on the scope of such studies. While the use of tumor specimens remains popular, more emphasis is being placed on cell lines as model systems where specific data can be directly combined with results from other studies. This article describes a genetic survey of the most widely used gastric adenocarcinoma cell lines. The allelotype at 351 polymorphic loci in 14 cell lines was obtained, and the results from the 4,900 polymerase chain reactions are displayed. In addition to confirming loss of heterozygosity on chromosome arms 6p, 7q, 17p, and 18, additional deletions on arm 5p and the pericentromeric regions of chromosomes 1 and 10 were detected. Areas that might contain homozygous deletions or amplifications also were mapped. The rate of microsatellite instability was quantified and shown to vary greatly among the different cell lines. Most important, this study serves as a genetic scaffold for the integration of past and future studies on the nature of the genetic defects in gastric cancer.

Adult↗
PubMed2001

[Clinical application of precision attachment prosthesis].

OBJECTIVE: In this study, clinical effects of three precision attachment prostheses were evaluated. METHODS: 16 DUOLOCK attachments 15 ANKER SYSTEM attachments and 8 MK 1 attachments were applied to restore 22 dentition defect cases, which consisted of 17 Kenny I defects, 3 Kenny II defects, 2 Kenny III defects. The clinical effects of three precision attachment prostheses were analyzed. RESULTS: 22 patients with precision attachment prostheses were followed up for 6 to 19 months. More than 86% patients felt comfortable, adaptive, aesthetics and fine retention. The rechecking results of 91 abutments displayed that all abutments were healthy without percussion pain, looseness, and disease of root tip and absorption of alveolar bone. The congestion and edema in gingival edge of 21 abutments were reduced after treatment. The masticatory efficiency measurement of 18 patients restored with precision attachment prostheses showed that the patients masticatory efficiency achieved 86.73% of the same age healthy dentition after 3 months, and 90.57% of the same age healthy dentition after 1 year. CONCLUSION: The three attachment prostheses can achieve satisfactory effect.

English Abstract↗
PubMed2000

Survey of genetic alterations in gastrinomas.

Gastrinomas are rare gastrin-secreting endocrine tumors that usually arise in the duodenum or pancreas and, if untreated, can cause severe peptic ulcers or metastatic disease. Although most tumors are sporadic they are especially common in patients with multiple endocrine neoplasia type 1 (MEN1), and most studies of these tumors have focused on the role of the MEN1 gene. Although the gene is commonly altered in sporadic tumors, this finding is not universal, and it is highly likely that other genetic defects play a significant role. In the present study, an in-depth analysis of the DNA of eight tumors was carried out in an effort to localize these areas. The experiments consisted of an analysis of 400 microsatellite marker loci distributed evenly throughout the human genome, and the results were confirmed with comparative genomic hybridization. Whereas deletions encompassing the MEN1 gene were seen in two tumors, the most striking result was multiple large rearrangements on chromosome 1 in two of the tumors with hepatic metastases. In several instances, an individual tumor had abnormalities of every informative maker on a given chromosome, presumably as a result of aneuploidy affecting that chromosome. Such defects were only seen in the four large or aggressive tumors, and the total number of chromosomes affected in a tumor ranged from 1 to a high of 13 in a patient who had an unusually aggressive tumor This tumor also showed microsatellite instability, and this is the first report of such a defect in gastrinomas. This study implicates chromosome 1 defects, aneuploidy, and perhaps mismatch repair defects as importan features of gastrinomas; deletions involving the MEN1 gene were con firmed, but the rest of the genome was free of large deletions or amplifications.

Allelic Imbalance↗
PubMed2000

Fetal nucleated erythrocyte recovery: fluorescence activated cell sorting-based positive selection using anti-gamma globin versus magnetic activated cell sorting using anti-CD45 depletion and anti-gamma globin positive selection.

BACKGROUND: Fluorescence activated cell sorting (FACS)-based anti-gamma (gamma) positive selection and magnetic activated cell sorting (MACS)-based anti-CD45 depletion followed by anti-gamma positive staining have been two of the most frequently used methods to isolate fetal cells from maternal blood. To date, there has been no direct comparison of fetal cell recovery by these two methods. This study was designed to address this issue. METHODS: Fluorescence in situ hybridization (FISH) was performed on nucleated anti-gamma positive cells using X and Y probes. Twenty-four maternal blood samples were obtained immediately after elective termination of pregnancy to ensure a detectable number of fetal cells. RESULTS: The yield and purity of fetal nucleated erythrocytes (FNRBCs) was statistically higher in FACS sorted samples (P < 0.01). The specificity of staining for FNRBCs was statistically higher in MACS sorted samples (P < 0.01). CONCLUSIONS: The data from this study demonstrate that both techniques have benefits and limitations. FACS has the advantage of having higher yield, higher purity, higher FISH efficiency and ease in microscope analysis, and MACS has the advantage of having higher specificity and less cell loss during FISH.

Antigens, CD↗
PubMed2000

[Analysis of sequence and polymorphism of R in S-type CMS maize].

The S-type CMS of maize was reported to be caused by a DNA region designated R in mitochondrial genomes. Through PCR using artificial primers, 1 kb DNA fragments were obtained from mitochondrial DNA of Tangxu and WB cytoplasm. The DNA sequences are almost the same as the sequence in R region of CMS-S. Using the DNA fragment from Tangxu cytoplasm as probe to scan the Mo17 CMS-J gene library, several positive clones appeared. The clone B39 contains a 6.7 kb BamHI fragment with R region. Nucleotide sequence analysis found two orfs including the chimeric orf77. Seventeen lines of maize under Mo17 and 77 nuclear background including N, T, C, S four types of cytoplasm were used for RFLP. Three types of R were discovered in S-type CMS, but not in C group. The R in N group was different from that in S group. T group had only part of R region. The Southern blot of Tangxü and Shuang cytoplasm in R regions showed different ratio of R in different nuclear backgrounds. The heterogeneity of R region suggests that the organization and rearrangement of R controlled by the nuclear background. R region seems to be involved in the mechanism of S group CMS. Varieties of structures of R, the ratio of three R types, different DNA sequences in R region of different CMS might be concerned with instability of S-type CMS.

Base Sequence↗
PubMed2000

Comparative study on efficacy of three sperm-separation techniques.

AIM: To evaluate the comparative effectiveness of real-time sperm separation technique (Wang's tube method) and other two conventional methods in isolating high-quality sperm preparation, and to compare the spouse pregnancy rate in intrauterine insemination (IUI) with sperm preparations isolated by these methods. METHODS: The effectiveness of the real-time sperm separation technique, the conventional swim-up and the Percoll discontinuous density gradient methods in isolating sperm preparations from 60 infertile patients (20 with apparently normal semen and 40, abnormal semen contaminated with microorganisms and other impurities) was evaluated and compared. The microorganisms to be removed included bacteria, virus, Chlamydia trachomaticum, Ureaplsama urealyticum, etc. The spouse pregnancy rates in IUI with sperm preparations isolated by these three techniques from 80 oligoasthenoteratospermic patients were also compared. RESULTS: The quality (including the percentages of normal form, normal-chromatin and motile sperm, and the grade of motility) of sperm obtained by the real-time sperm separation technique was much higher (P < 0.01) as compared with those by the other two methods. The Wang's tube method was also more effective in removing microorganisms and other impurities. The method provided a higher IUI pregnancy rate than the other two sperm separation techniques (P < 0.05). CONCLUSION: The real-time sperm separation technique is the most effective method so far available in isolating high-quality sperm samples to be used in assisted reproduction.

Adult↗
PubMed1999

Fetal cell identifiers: results of microscope slide-based immunocytochemical studies as a function of gestational age and abnormality.

OBJECTIVE: We evaluated monoclonal antibodies to 3 cell surface and 3 intracellular antigens for their relative usefulness as markers to identify fetal cells in maternal blood. STUDY DESIGN: With indirect immunocytochemical labeling techniques, antigen expression was studied in 52 fetal blood samples as a function of gestational age, fetal karyotype, the presence of multiple anomalies detectable on ultrasonography, and anemia. RESULTS: A decline in the expression of these antigens as gestational age advanced was demonstrated. Samples from karyotypically abnormal fetuses, fetuses with multiple anomalies, and anemic fetuses showed an antigenic distribution that was immature for gestational age. In normal fetuses zeta globin and epsilon globin expression decreased after 12 to 14 weeks, potentially limiting the utility of these proteins as fetal cell markers in the isolation of fetal cells from maternal blood. CONCLUSIONS: The results of this study demonstrate a fetal developmental hematologic profile that varies with gestational age and also with pathologic condition. Antibodies to the gamma chain of fetal hemoglobin and the transferrin receptor (CD71) are the most useful fetal cell-identifying reagents.

Abnormalities, Multiple↗
PubMed1999

[Establishment of a high germline competent C57BL/6J ES cell line].

Eleven ES cell lines from C57BL/6J mice were established, with the primary culture of mice embryos as feeder cells and 1 x 10(3) units Leukemia Inhibitory Factor (LIF) in the DMEM (high glucose) medium. The frequency of establishment was 9.6%. Five of these ES cell lines were demonstrated karyotypically normal with diploid composition of over 70%. They shared the characteristics of early embryonic cells: positive for alkaline phosphatase activity and oct4 gene expression. They also showed high potency to differentiate into wide types of cells in vivo. Following injection of the blastocysts, three of them showed abilities to give rise to chimeras and MESPU35 cell line was identified to have high efficiency of colonization into the germline. The clones of MESPU35 cells maintained the germline competence and the mutant clone also retained the high potency to participate into the development of embryos. MESPU35 cells can serve as a valuable vehicle for the production of mutant mice.

Animals↗
PubMed1999

[Manufacture and application of the SJ-1 bolt attachment prosthesis]

OBJECTIVE:This study provided a method of manufacture and using for SJ-1 bolt attachment prostheses clinic application.METHODS:SJ-1 bolt attachment prostheses were applied to restorate 10 cases distal extension edentulous area.The patients had been observed for two years.RESULTS:Patients feel the bolt attachment RPDs comfortable,adaptive.CONCLUSION:This prosthesis was fine retention,masticator efficiency and aesthetics.

Journal Article↗
PubMed1999

[Effect of the number of splinted abutments on stress distribution of support tissue]

OBJECTIVE:This study applied an SJ-1 bolt attachment partial denture to restorate distal extension edentulous areas.Finite element analysis (FEA) was used to monitor induced around abutment supporting tissues under the different number of splinted abutments.METHODS:Finite element analysis. RESULTS:The result demonstrate that the reduction of the number of splinted unit from three to two resulted in an insignificant increase of stress records,whereas reduction of the number from two to one resulted in a significant increase of stress nine times greater than the three unit splint values.CONCLUSION:Hence,at least two teeth on each side should be splinted when SJ 1 bolt(extracoronal) distal extension attachment prostheses are used.

Journal Article↗
PubMed1999

[Effect of the abutments with reduced periodontal support on stress distribution of support tissue]

OBJECTIVE:This study applied finite element analysis (FEA) compared stress distribution characteristics of mandible,bilateral,SJ-1 bolt(extracoronal) distal extension attachment prostheses when the abutments were subject to eight different loss of periodontal support.METHODS:Finite element analysis.RESULTS:It was shown that periodontal support loss results in increased stress of the terminal abutment tooth without sudden changes.CONCLUSION:Compared favorable stress distribution result from splinted compromised abutment,and the first premolar periodontal support loss less than that of the second premolar and this loss below 30%.

Journal Article↗
PubMed1998

[Regulation of ACTH4-9 analogue on the Ca2+ level of mouse hippocampal synaptosomes].

The effect of ACTH4-9 analogue Org2766 on the [Ca2+]i level of mouse hippocampal synaptosomes was studied. Synaptosomal free calcium concentration ([Ca2+]i) and 45Ca2+ uptake were measured respectively by spex cation measurement system and Beckman LS-9800 liquid scintillation spectrometer. Low dose of Org2766 did not change synaptosomal [Ca2+]i level, but decreased 45Ca2+ uptake. High dose of Org2766 increased [Ca2+]i without affecting 45Ca2+ uptake. Low dose of Org2766 inhibited the anisomysin-induced increase of synaptosomal [Ca2+]i while high dose had no effect. These results suggest that the regulation of Org2766 on hippocampal synaptosomal Ca2+ level may be achieved by inhibiting the Ca2+ influx and increasing the release of synaptosomal calcium pool.

Adrenocorticotropic Hormone↗