PubMed Health⌕ Search

Biomedical subjects

J Y Chu

Publications and source records attributed to J Y Chu.

At least 19 recordsLinked to original sources
PubMed2006

HLA-A, HLA-B, and HLA-DRB1 alleles and haplotypes in Naxi and Han populations in southwestern China (Yunnan province).

The frequencies of the human leukocyte antigen alleles HLA-A, HLA-B, and HLA-DRB1 and the A-B-DRB1, A-B, and B-DRB1 haplotypes were studied in Naxi and Yunnan Han populations using polymerase chain reaction (PCR)-sequence-specific amplification for alleles A and B and a PCR-microtiter plate hybridization method for the DRB1 allele. A total of 8 A, 19 B, and 30 DRB1 alleles were found in the Naxi population, and 15 A, 21 B, and 36 DRB1 alleles were found in Yunnan Han population. The common A-B-DRB1 haplotypes in the Naxi population were A*24-B*15-DRB1*1202, A*11-B*15-DRB1*0405, A*11-B*15-DRB1*1202, A*11-B*38-DRB1*08032, and A*11-B*55-DRB1*0405; the common A-B haplotypes were A*11-B*15, A*11-B*38, and A*24-B*15; and the common B-DRB1 haplotypes were B*15-DRB1*1202, B*38-DRB1*08032, and B*48-DRB1*1201. In the Yunnan Han population, the common A-B-DRB1 haplotypes were A*24-B*15-DRB1*1501, A*24-B*46-DRB1*08032, and A*24-B*15-DRB1*1201; the common A-B haplotypes were A*24-B*15, A*24-B*46, and A*34-B*46; and the common B-DRB1 haplotypes were B*15-DRB1*1501, B*46-DRB1*09012, and B*46-DRB1*1401. Phylogenetic tree and principal component analyzes based on HLA-A, HLA-B, and DRB1 allele frequencies suggested that the Naxi ethnic group belongs to the southern Chinese groups, while the Yunnan Han population is a characteristic population located intermediate between northern and southern Chinese groups, although they live in the southwest of China.

Alleles↗
PubMed2004

Association of Fcgamma receptor IIb polymorphism with susceptibility to systemic lupus erythematosus in Chinese: a common susceptibility gene in the Asian populations.

The association of Fcgamma receptor (FcgammaR) polymorphisms with systemic lupus erythematosus (SLE) has been demonstrated in various populations; however, the results have been inconsistent. We recently identified a single-nucleotide polymorphism encoding a non-synonymous substitution, Ile232Thr (I232T), of FCGR2B and its association with SLE in Japanese and in Thais. Multiple functional FcgammaR genes with polymorphisms (FCGR2A, FCGR2B, FCGR3A, and FCGR3B) cluster in 1q23, and some of them are in linkage disequilibrium (LD). To differentiate contributions from multiple-linked loci, comparison of different populations may provide useful information. In this study, we analyzed the above four FCGR polymorphisms of the Chinese patients and controls for the association with SLE. FCGR2A-H131R, FCGR2B-I232T, FCGR3A-F176V, and FCGR3B genotypes were determined in 167 Chinese patients with SLE and 129 healthy controls. Association was examined using case-control analysis. Allele frequencies of FCGR2B-232T and FCGR3A-176F were significantly increased in SLE [odds ratio (OR) = 1.67 and OR = 1.41, respectively]. Interestingly, while these alleles had a tendency of positive LD in the controls, FCGR2B-232T was in positive association with FCGR3A-176V in SLE, suggesting that these two alleles were associated with SLE in an independent manner. Comparison between SLE with and without nephritis indicated significant association of FCGR2B-232T with nephritis (OR = 2.65). When the present results were combined with our previous data on the Japanese and the Thais using meta-analytic methods, highly significant and independent association was observed for FCGR2B and FCGR3A genotypes. These results strongly suggested that FCGR2B is a common susceptibility factor to SLE in the Asians.

Adult↗
PubMed2001

Mitochondrial DNA polymorphisms in Yunnan nationalities in China.

Nucleotide sequences of the D-loop region of human mitochondrial DNA from four Yunnan nationalities, Dai, Wa, Lahu, and Tibetan, were analyzed. Based on a comparison of 563-bp sequences in 99 people, 66 different sequence types were observed. Of these, 64 were unique to their respective populations, whereas only 2 types were shared between the Lahu and Wa nationalities. The D-loop sequence variation and phylogenetic analysis suggested that the 99 mtDNA lineages were classified into eight clusters in the phylogenetic tree. All lineages that had a 9-bp deletion in the COII/tRNALYs intergenic region appeared in one cluster in the D-loop tree, suggesting a single event of the deletion in the Yunnan nationalities studied. Genetic distances, based on net nucleotide diversities between populations including Han Chinese and mainland Japanese, revealed that the Dai, Wa, Lahu, and Han Chinese are closely related to each other, while Tibetan and mainland Japanese formed a single cluster. The bootstrap probability of separation between the Dai-Wa-Lahu-Chinese clade and the Tibetan-Japanese clade was 99%, indicating that there are at least two different origins among minority groups in Yunnan province. Although the genetic distance between Tibetan and Japanese within the clade is rather long, the results may shed light on the origins of mainland Japanese.

Base Sequence↗
PubMed2001

[Genetic relationship among four Yunnan populations revealed by sequence of mtDNA D-loop].

mtDNA D-loop noncoding region 16048-16569 and the following 1-41 (563 bp) in 99 individuals of four Yunnan ethnic minorities (Dai, Wa, Lahu and Tibetan) were sequenced and then a phylogenetic tree was reconstructed by Neighbor-Joining method. These 99 mtDNA lineages were classified into 3 genotype groups in the tree. All lineages with 9 bp deletion in the COII/tRAN(Lys) intergenic region were clustered in group I, some individuals of Dai, Lahu, Wa and only 2 Tibetan individuals clustered in group II, individuals of all four populations were included in group III. A phylogenetic tree of the four populations was constructed by NJ method on the basis of estimate of net genetic distance among them. Our results showed, the genetic distance among Dai, Wa and Lahu is very close, but far from Tibetan, their genetic distance is similar to their geographic distance. Although both as descendants of ancient Di-Qiang tribe in history and speaking similar language, Lahu and Tibetan are not closely related. This result indicates that there are different origins of these two populations.

China↗
PubMed2001

[Genetic relationships among six Chinese populations revealed by analysis of 30 autosomal STRs].

30 autosomal STRs of 6 Chinese populations (Bai, Naxi, Tu, Sala, Han in Shandong, She) were amplified by multiplex PCRs using fluerescein-labelled primers. Shriver's Dsw was estimated on the basis of the results of the genescanning and genotyping after running unnatural PAGE of the PCRs' products on ABI 377 sequencer. Phylogenetic trees were constructed by using Neighbor-Joining and UPGMA method based on Dsw, and then the genetic relationships among them were analyzed referring to some relative informations. Our results indicated that the genetic distance between Sala and Tu is near, 0.033. But the distances between Sala and other four populations are far, over 0.12; Tu is close to Naxi and Shandong Han, and the distances are 0.038, 0.063 respectively; The distance between Bai and Han is the nearest, 0.007, but there is a distance, 0.075, between Bai and Naxi, and a far distance, 0.112, between Bai and Tu; The distance between Naxi and Han is 0.100 and the distances between She and other 5 populations are all over 0.12. In both of the NJ and UPGMA phylogenetic trees, Naxi, Tu and Sala is one cluster and Bai and Han is another cluster. She is a single branch. These results, basically consistent with 6 Chinese populations' geographic distribution and histories, can provide some genetic information to comprehensively study their origin, migration, formation and development with their historical records and archaeological evidence.

Asian People↗
PubMed2001

[Distribution of F13A01, FESFPS and vWA loci in ten minority populations in Yunnan of China].

The short tandem repeats (STR) is a kind of DNA sequence formed repeatedly and connectively subjected to a core unit of several base pairs. The non-interfered multi-PCR was applied with 3 loci in the same reaction system. By using the technique of denaturing polyacrylamide gel electrophoresis and silver stain, the allele frequencies distributions of 3 loci: F13A01, FESFPS and vWA in 10 minority populations only resided in Yunnan Province: Bai, Dai, Achang, Jingpo, Deang, Lahu, Bulang, Hani, Pumi and Jino. A satisfactory result was obtained and some significant genetic differences were noticed in different populations.

Antigens↗
PubMed2001

[Distribution of MICA microsatellite in 13 population groups of China].

The genetic data of MICA microsatellite were obtained by genotyping 577 samples in 13 population groups of China, which are Han-YN, Han-GD, Han-SD, Bai, Dai, Lahu, Li, Naxi, Sala, She, Tu, Wa and Zang-YN, with genescan. Five alleles have been observed in the population groups, which are A4, A5, A5.1, A6 and A9. A5 allele is the most frequent in all population groups except Lahu and Li, while the most frequent allele for Lahu and Li is A5. 1 and A4 respectively. The second most frequent allele is the A5.1 in Han-YN, Han-SD, Dai, Naxi, Sala, She, and Wa. The lest frequent allele for Han-YN, Han-GD, Lahu, Naxi, She, Wa is the A6 which is not observed in Li. A4 allele is the lest frequent in Han-SD, Bai, Dai, Sala, Tu, Zang-YN. The results show that the distribution of MICA microsatellite is different in these population groups, and the polymorphism information contents (PIC) of this microsatellite is high. It is a potential useful marker in the study of human origin and migration, personal identification, gene mapping and location, and disease diagnosis.

China↗
PubMed1999

Philippine population database at nine microsatellite loci for forensic and paternity applications.

Allele frequency distributions for a Filipino population from the National Capital Region (NCR) were determined for eight STR loci: HUMF13A01, HUMFES/FPS, HUMvWA, HUMFOLP23, HUMD8S306, HUMCSFIPO, HUMTPOX and HUMTHO1; and a VNTR locus: D1S80. Statistical analysis showed that the nine loci showed no deviations from Hardy-Weinberg and linkage equilibrium rules. The average power of paternity exclusion for the nine loci is 0.9962 and the discriminating power is 1-2 x 10(-9). The data obtained from this study will be used as reference data for forensic DNA typing in the Philippines.

DNA Fingerprinting↗
PubMed1999

Prevalence study and molecular characterization of alpha-thalassemia in Filipinos.

In order to determine the prevalence and molecular basis of alpha-thalassemia (thal) among Filipinos, a total of 2954 Filipinos in Taiwan were enrolled in this study. A complete blood count was done for every subject. Those with microcytosis (MCV less than 82.5 fl) were studied with hemoglobin (Hb) high-performance liquid chromatography to determine the levels of Hb A2 and Hb F, and with an enzyme immunoassay to determine plasma ferritin levels. Those who had microcytosis and normal or low levels of Hb A2 and Hb F were further studied with molecular methods for alpha-globin gene mutations. We used Southern blot hybridization and/or the polymerase chain reaction to detect Southeast Asian deletion, Filipino deletion, rightward and leftward single alpha-globin gene deletions, and Hb Constant Spring and Hb Quong Sze. Specific amplification and direct DNA sequencing of the alpha2- and alpha1-globin genes were carried out in apparent alpha-thal carriers without any of the above-mentioned mutations. Our results showed that in Filipinos the prevalence of alpha-thal 1 was 5% (147 carriers) and that of alpha-thal 2 was 1.7% (49 carriers); two had Hb H disease. Among the alpha-thal 1 carriers, 89 had the Southeast Asian deletion and 58 had the Filipino deletion. Among the alpha-thal 2 carriers, 48 had a rightward deletion and one had a leftward deletion. None had Hb Constant Spring or Hb Quong Sze. Specific amplification and DNA sequencing in five apparent alpha-thal carriers did not reveal mutations in the 2-kb region spanning the alpha2- and alpha1-globin genes. The molecular defects of alpha-thal in Filipinos were different from those in the neighboring ethnic groups. Elucidation of the alpha-thal mutations in Filipinos is useful in the genetic counseling and prenatal diagnosis of this common disease.

Gene Deletion↗
PubMed1999

Modeling of occupant dynamics during automobile rear-end impacts.

Procedures for studying the dynamic response of the occupant within a rear-end impacted vehicle are presented. Most of the researches in the impact analysis were performed by experimental approach and this costs a lot of time and money. Especially, the repeatability is very hard to produce in a destructive condition. Most of all, the analytic parameters can be investigated are limited by the experimental approach. By using numerical techniques, this research employs Kane's equation and Huston's method to develop a simulated system with visual graphic output to observe the rear-end impact response. According to the simulated results, at a constant seatback angle the maximum acceleration values of head and chest increased with the increasing of impact velocity. Furthermore, at a constant impact velocity the relative rotation angle of a passenger's head to chest decreased with the increasing of initial seatback angle.

Acceleration↗
PubMed1998

Genetic relationship of populations in China.

Despite the fact that the continuity of morphology of fossil specimens of modern humans found in China has repeatedly challenged the Out-of-Africa hypothesis, Chinese populations are underrepresented in genetic studies. Genetic profiles of 28 populations sampled in China supported the distinction between southern and northern populations, while the latter are biphyletic. Linguistic boundaries are often transgressed across language families studied, reflecting substantial gene flow between populations. Nevertheless, genetic evidence does not support an independent origin of Homo sapiens in China. The phylogeny also suggested that it is more likely that ancestors of the populations currently residing in East Asia entered from Southeast Asia.

Animals↗
PubMed1998

Allele frequency distributions of the polymorphic STR loci HUMVWA, HUMFES, HUMF13A01 and the VNTR D1S80 in a Filipino population from Metro Manila.

Allele frequency distributions at the short tandem repeat (STR) loci HUMVWA, HUMFES, HUMF13A01 and of the variable number of tandem repeat (VNTR) locus D1S80 were determined in a Filipino population from Metro Manila (103 individuals) by use of the polymerase chain reaction (PCR) followed by polyacrylamide gel electrophoresis (PAGE). The exact test demonstrated that all four loci had no deviations from Hardy-Weinberg equilibrium (HWE) with the only reservation that the exact test p-value for F13A01 is weak. The discriminating power is 0.82 for D1S80, and the expected exclusion chance is 0.85 for F13A01, 0.83 for FES, and 0.93 for VWA. The observed heterozygosity rates are 0.63 for D1S80, 0.66 for F13A01, 0.67 for FES, and 0.80 for VWA. The exact test for independance between all loci gave a p-value of 0.0195. This is the first time that Filipino population data of DNA loci of forensic importance are reported.

Alleles↗
PubMed1998

Cognitive screening examinations for silent cerebral infarcts in sickle cell disease.

OBJECTIVE: In children with sickle cell disease (SCD), silent cerebral infarcts are the most frequent cause of neurologic injury. We determined the sensitivity and specificity of selective neurocognitive measures when separating children with silent cerebral infarcts and SCD from sibling controls. Additionally, we tested the validity of the same cognitive measures to identify patients with overt strokes. METHODS: We examined performance on a neuropsychologic battery containing measures of attention/executive, spatial, language, memory, and motor functioning for seven children with SCD and silent cerebral infarct, 21 children with SCD and overt stroke, and 17 normal siblings. Diagnosis of cerebral infarct was based on results of MRI. RESULTS: Measures from the attention and executive domains were the most useful for identifying children with silent cerebral infarct. The Test of Variables of Attention was the most robust measure and yielded a sensitivity rate of 86% and a specificity rate of 81%. This measure also showed a sensitivity rate of 95% in identifying overt stroke. CONCLUSIONS: Brief cognitive screening measures, if properly constructed, may be an effective means of identifying children with silent cerebral infarct. Future prospective studies should be pursued to assess the utility of cognitive screening for silent cerebral infarcts in SCD.

Adolescent↗
PubMed1998

[Distribution of CSF1PO, TPOX and TH01 loci in Han Chinese].

The application of short tandem repeat (STR) polymorphisms has stimulated progress in the elaboration of linkage maps, forensic identification and paternity determination, characterization of disease genes, and simplification and precision of DNA typing. In this report. We have carried out DNA extraction from blood multiplex amplification of CSF1PO, TPOX and TH01. By using denaturing polyacrylamide gel electrophoresis and silver stain, we investigated the allele frequencies of CSF1PO, TPOX and TH01 loci in Han group living in Yunnan provice of China. In this study, 9 alleles and 22 genotypes of CSF1PO locus were observed; In the locus TPOX, 6 alleles and 14 genotypes were observed. In the TH01 locus, 6 alleles and 19 genotypes were observed.

Alleles↗
PubMed1997

Misdiagnosis of homozygous alpha-thalassaemia 1 may occur if polymerase chain reaction alone is used in prenatal diagnosis.

The polymerase chain reaction (PCR) is a quite sensitive diagnostic tool but its specificity may be hampered because of contamination of foreign DNA. In order to determine the diagnostic accuracy of PCR in diseases due to gross gene deletion, a total of 180 fetuses at risk of homozygous South-East Asian deletion (SEA) of alpha-globin genes were included for study. Both PCR and Southern hybridization (SH) were performed. By PCR, three of 43 affected fetuses were misdiagnosed as heterozygotes; four of 50 normal fetuses were misdiagnosed as heterozygotes; and four of 87 heterozygotes were misdiagnosed, two as normal and two as affected. Misdiagnosis in affected and normal fetuses was most likely due to maternal DNA contamination, while misdiagnosis in heterozygotes was probably due to a failed PCR. In the experiments with PCR in which we added DNA from a carrier woman to an affected or a normal fetus, a level of 1/64 and 1/16 contamination resulted in the appearance of normal and SEA breakpoint sequences, respectively. In the SH experiments using artificially contaminated DNA, a level of 1/4 contamination showed the normal and SEA bands, respectively, while a contamination level lower than 1/8 and 1/16 respectively did not reveal contamination bands. The high sensitivity of PCR makes it easier to amplify contaminated DNA. For accurate prenatal diagnosis, PCR should be performed very carefully and SH seems to be a useful back-up.

Diagnostic Errors↗
PubMed1996

Aberrant CD2 expression in precursor-B acute lymphoblastic leukemia of childhood.

Aberrant CD2 expression in childhood precursor-B ALL is rare and has recently been reported with an incidence of 3.6% in a study by Cantu-Rajnoldi et al. [Haematologica 77:384, 1992]. There was no association of the CD2 co-expression with other known prognostic factors. Our study represents the second one in the literature. Out of 60 childhood acute lymphoblastic leukemias, analyzed morphologically and by flow cytometric immunophenotyping, 49 were of precursor B origin. Of these 49 cases, CD2 co-expression was detected in 2, yielding an incidence of 4.1%. The complete immunophenotypic profiles of these two cases were as follows, respectively: (1) CD19+, CD20-, CD24+, CD10+, sig-, CD2+, CD3-, CD5-, CD7-, CD13-, CD33-, CD34+, Tdt+; and (2) CD19+, CD20-, CD24+, CD10+, sig-, CD2+, CD3-, CD5-, CD7-, CD13+, CD33-, CD34+, Tdt+. Cytogenetic analysis revealed a normal male chromosome pattern in case 1 and an abnormal female chromosome pattern [4 cells: 46, XX, del (6q) (q21 q23) and 9 cells: 46, XX, del (11q) (q14 q23)] in case 2. Both patients were in continuous complete remission at last follow-up.

Antigens, CD↗
PubMed1996

Listeria spinal cord abscess--clinical and MRI findings.

BACKGROUND: Intramedullary spinal cord abscess due to Listeria Monocytogenes is an uncommon condition usually affecting immunocompromised patients. METHOD: Case study. RESULTS: A 69-year-old man presented with 3 weeks history of subacute paralysis of both lower limbs and the left upper limb. Myelogram and CT scan showed a widened upper cervical cord. CSF revealed lymphocytosis, moderately elevated protein and depressed glucose. A gadolinium-enhanced MRI showed diffuse cervical cord edema with two ring-enhancing lesions at C2-C3. Blood and CSF cultures grew Listeria Monocytogenes. He received IV ampicillin and gentamycin; the latter was discontinued after 1 month due to nephrotoxicity. Serial MRI over the next 3 months showed significant reduction in the size of these abscesses. The patient made a modest improvement in the power of his lower limbs, however he remained bed-ridden. Aside from being a mild, diet-controlled diabetic, there was no evidence of immunosuppression. CONCLUSION: Listeria spinal cord abscess is a treatable disorder and should be considered in the differential diagnosis in patients with a subacute onset of spinal cord dysfunction.

Abscess↗