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Biomedical subjects

Lin He

Publications and source records attributed to Lin He.

176 records · Page 10Linked to original sources
PubMed2003

[Genetic analysis of a Chinese pedigree with congenital synpolydactyly].

Syndactyly is a limb malformation that shows a characteristic manifestation in both hands and feet. This condition is inherited as an autosomal dominant trait with reduced penetrance. Clinical presentation, in general, is complete or partial webbing between 3rd and 4th fingers. Syndactyly type I, II and III were mapped to 2q34-36, 2q31-q32 and 6q21-23.2 respectively. Syndactyly type II is named as synpolydactyly (SPD). Expansion of a polyalanine tract in the HOXD13 gene is known to cause synpolydactyly. HOXD13 gene locates in the HoxD complex. Nine homologous genes (HOXD1, -D3, -D4, -D8, -D9, -D10, -D11, -D12, -D13) of HoxD complex locate on chromosome 2 in the order of HOXD1 to HOXD13, among which HOXD13 is closest to the centromere. Deletions and duplications in HoxD complex or its upstream regulator factors have been identified to cause hand heteroplasia and consequently lead to abnormity of finger number or abnormity of configuration. We performed linkage analysis in a kindred with autosomal dominant hereditary syndactyly. Tight linkage to markers on chromosome 2q31-q32 (maximum two-point lod score: 6.78 at recombination fraction theta = 0.00) was observed. Multipoint linkage analysis produced a maximum LOD score of 7.02. Haplotype construction and analysis of recombination events narrowed this locus to a 20.61 cM region between markers D2S2302 and D2S315. No mutation was found in the coding region, the intro-exon boundaries, or part of the promoter region of HOXD13. Our result demonstrates that synpolydactyly locus in the Chinese Han Population is in the region of chromosome 2q31-q32 but a different causal gene can be involved.

China↗
PubMed2003

[Study on relative bioavailability of aspirin in afenca tablet].

Salicylic acid is a kind of active metabolite of aspirin in vivo. In this study, its concentration in plasma was detected by RP-HPLC after twenty four healthy male volunteers were given each a single dose of oral Afenca test and reference preparations. The experiment data were calculated with 3P97 program. The results were analyzed by ANOVA and two- and one-sided t tests. The relative bioavailability of salicylic acid was 105.36% +/- 14.15%; AUC0-T of salicylic acid of test and reference preparations were 103.10 +/- 11.92 micrograms.h/ml and 98.45 +/- 13.49 micrograms.h/ml respectively; Tmax were 1.5 +/- 0.5 h and 1.5 +/- 0.5 h; Cmax were 19.31 +/- 2.47 micrograms/ml and 18.95 +/- 2.49 micrograms/ml. Bioequivalent evaluation of two preparations by analyzing with two- and one-sided t tests showed that the two preparations were bioequivalent on the basis of salicylic acid (t1 > or = t1-0.05(22), t2 > or = t1-0.06(22)).

Administration, Oral↗
PubMed2002

Particles for multiplexed analysis in solution: detection and identification of striped metallic particles using optical microscopy.

In this report, we present data demonstrating that cylindrical metallic particles, with various submicrometer striping patterns, may be readily distinguished in an optical microscope. Accurate particle identification is discussed relative to synthesis reproducibility and the limitations of optical microscopes. Results from a library of these particles, of which over 100 different striping patterns have been produced, are presented. For these particles, made with Au and Ag stripes, more than 70 patterns may be identified with greater than 90% accuracy. The ability to chemically modify the surface of these particles, making them useful for bioanalytical measurements, is also demonstrated. Finally, we discuss improvements in our manufacturing and identification processes that will lead to both larger numbers of striping patterns and improved identification accuracy.

Diagnostic Imaging↗
PubMed2002

Polymorphisms of chromogranin B gene associated with schizophrenia in Chinese Han population.

Chromogranin is a widespread family of proteins in the neurosystem, whose function is guiding the sorting and secretion of neuropeptides. Using functional and positional evidences, chromogranin B was selected as a candidate gene for schizophrenia. We systematically screened all the promoter and exon regions of the gene and detected 15 single nucleotide polymorphisms (SNPs), among which four SNPs (including two non-synonymous SNPs) were selected for association analysis. In a cohort of Chinese Han schizophrenia cases and controls, the results of both the individual SNPs and the haplotypes of SNPs were significantly positive (P<0.01). Our results confirm the role of neuropeptides in the pathogenesis of schizophrenia.

Adult↗
PubMed2002

Effects of removal of the N-terminal amino acid residues on the activity and conformation of firefly luciferase.

A series of deletion mutants were constructed using polymerase chain reaction (PCR) to investigate the roles of luciferase N-terminal residues. The coding sequences of the first 0 (Luc0), 6 (Luc6), 7 (Luc7), 8 (Luc8), 9 (Luc9), 10 (Luc10) and 20 (Luc20) amino acids of the N-terminus were deleted and inserted into the prokaryotic expression vector pBV220. The results showed that the enzymes were completely inactivated when the first eight or more N-terminal amino acids were removed. The recombinant Luc0 and mutants Luc6 and Luc7 were purified to homogeneity by ammonium sulfate precipitation and liquid chromatography for determination of their activity and conformational changes. The activity assay showed that removal of the first six amino acids resulted in 29% loss of enzymatic activity while removal of the first seven amino acids resulted in nearly complete inactivation (with remaining activity <0.5% of the original activity). Circular dichroism spectra showed no significant secondary structure changes. But the fluorescence emission maximum red-shift indicated some conformational changes. Luc6 and Luc7 were more sensitive to guanidine unfolding than Luc0. The present result indicated the significant role of Ile7 to the luciferase stability.

Animals↗
PubMed2002

Loss of heterozygosity on long arm of chromosome 22 in sporadic colorectal carcinoma.

AIM: The loss of heterozygosity (LOH) on tumor suppressor genes is believed to play a key role in carcinogenesis of colorectal cancer. In this study, we analyzed the LOH at 5 loci on the long arm of chromosome 22 in sporadic colorectal cancer to identify additional loci involved in colorectal tumorigenesis. METHODS: Five polymorphic microsatellite markers were analyzed in 83 cases of colorectal and normal DNA by PCR. PCR products were eletrophoresed on an ABI 377 DNA sequencer; Genescan 3.1 and Genotype 2.1 software were used for LOH scanning and analysis. Comparison between LOH frequency and clinicopathological data were performed by chi(2) test. P<0.05 was considered as statistically significant. RESULTS: The average LOH frequency on chromosome 22q was 28.38 %. The region between markers D22S280 and D22S274 (22q12.2-q13.33) exhibited relatively high LOH frequency. The two highest LOH loci with frequencies of 35.09 % and 34.04 % was identified on D22S280 (22q12.2-12.3) and D22S274 (22q13.32-13.33). 8 cases showed LOH at all informative loci, suggesting that one chromosome 22q had been completely lost. On D22S274 locus, LOH frequency of rectal cancer was 50 % (9/18), which was higher than that of proximal colon cancer (12 %, 2/17) (P=0.018). The frequency of distal colon cancer was 42 % (5/12), also higher than that of proximal colon cancer. But there was no statistical significance. Putting both the tumors in distal colon and rectum together into consideration, the frequency, 47 % (14/30), was higher than that of proximal colon cancer (P=0.015),suggesting the mechanism of carcinogenisis was different in both groups. CONCLUSIONS: This study provided evidence for the involvement of putative tumor suppressor genes related to the sporadic colorectal carcinoma on chromosome 22q. The tumor-suppressor-gene(s) might locate on the 22q12.2-12.3 and/or 22q13.32-13.33.

Adult↗
PubMed2002

Single-nucleotide polymorphisms in NGX6 gene and their correlation with nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is rare in most parts of the world, but prevalent in southern China. Recently, a NGX6 gene was cloned, which is located in the region of minimal heterozygosity deletion at 9p21.3-22.1 and is down-expressed in NPC. The latest results suggest that the NGX6 gene is a candidate tumor suppressor for NPC. A correlation study using 2 single-nucleotide polymorphisms (SNPs) within NGX6 gene by means of dynamic allele specific hybridization (DASH) was performed in 105 unrelated case subjects and 183 control subjects which matched to the NPC cases in age, sex and residence. Significant results were obtained for one SNP mark (rs879284), which was located at -237 bp 5' up-stream of NGX6 gene, and the relative risk of this SNP mark was 3.93 (genotype CT) and 2.27 (genotype TT). The result has proved again that NGX6 gene may play a certain role in oncogenesis and development of nasopharyngeal carcinoma. The SNP mark rs879284 may influence on the expression of NGX6 gene due to its location on chromosome.

Adult↗
PubMed2002

[Allelic analysis on chromosome 5 in sporadic colorectal cancer patients].

OBJECTIVE: To evaluate and map the putative tumor suppressor loci on chromosome 5 involved in tumor progress or metastasis. METHODS: Chromosome 5 of 83 patients with sporadic colorectal cancer was systemically screened. Fifteen microsatellite marker primers labeled with 3 different fluorescents were used to amplify the corresponding loci of the genome DNA. The PCR products were electrophoresed on a 377 PRISM sequencer and the fluorescent signals were analyzed with Genotyper and Genescan software. RESULTS: The highest loss of heterozygosity (LOH) ratio was found at D5S416 (48.15%) on 5p and at D5S471 (38.71%) on 5q. The region (5q13.3 - 31), where D5S471 and 3 neighboring loci (D5S428, D5S2027 and D5S2115) reside, presented high frequent LOH. CONCLUSION: The deletion of APC, MCC, CTNNA1 and IL cluster in the 5q 13.3 - 31.1 area play important role in the tumorogenesis of colorectal cancer, and the expected existence of another novel tumor suppressor gene on 5p is possible.

Adult↗
PubMed2002

[Loss of heterozygosity analysis to define putative region involved in tumor differentiation and metastases in sporadic colorectal cancer patients].

OBJECTIVE: To detect putative suppressor loci involved in tumor progressing or metastases. METHODS: Thirty microsatellite marker primers were employed to amply the corresponding loci of the genome DNA from 83 patients with sporadic colorectal cancer. The PCR products were electrophoresed on a 377 PRISM sequencer and the fluorescent signals were analyzed by Genotyper and Genescan software. RESULTS: The data were obtained from 24 loci, with an average LOH frequency of 15.16%. The LOH at D2S206 and D2S364 was more frequent than 30%, and was less than 20% at the rest loci. Significant difference was observed between the percentage of LOH and tumor staging or differentiation at D2S142 (2q24.1), D2S126 (2q35), D2S2211 (2p24.2), D2S305 (2p23.3). Occarrence of deletion at the later two loci was correlative. CONCLUSIONS: Frequent LOH was not observed at the loci around known mismatch repair genes on chr. 2. The region between D2S305 (2p23.3) and D2S2211 (2p24.2) deleted holistically, and was correlated to the stage and differentiation of tumor attended by D2S142 (2q24.1) and D2S126 (2q35) on 2q. It is suggested that unknown genes associated with tumor progressing or metastases reside in the two loci on 2q or the region on 2p.

Adult↗
PubMed2002

Loss of heterozygosity of chromosome 20 in sporadic colorectal cancer.

OBJECTIVE: To analyze the loss of heterozygosity (LOH) of chromosome 20 in patients with sporadic colorectal cancer to identify additional loci involved in colorectal tumorigenesis. METHODS: Polymorphic microsatellite markers were analyzed in 83 colorectal cancer patients' tumor and normal DNA by PCR. PCR products were electrophoresed on an 377 DNA sequencer. Genescan 2.1 and Genotype 2.1 software were used in the LOH scanning and analysis. Comparisons between LOH frequency and clinicopathological data were performed by chi(2) test. P < 0.05 was considered statistically significant. RESULTS: The average LOH frequency in the long arm, short arm and whole chromosome 20 was 21.1%, 26.7% and 22.8%, respectively. Chromosome 20 exhibited relatively high LOH frequency, particularly in the regions of 20p and 20q11.1-q13.1. CONCLUSION: There is notable genetic instability on chromosome 20 in sporadic colorectal carcinoma patients; that is, mutation on chromosome 20 is closely associated with sporadic colorectal carcinogenesis. Also, there may be tumor suppressor genes related to sporadic colorectal carcinoma near the region 20q11.1-q13.1.

Adult↗
PubMed2002

[The use of muscle autograft denatured by microwave for repair of gap in removal of facial neuroma].

OBJECTIVE: To study the clinical value of muscle autograft denatured by microwave for repair of gap in removal of facial neuroma. METHODS: A case of patient with a larger facial nerve Schwann cell neuroma was reported. Based on the good results of our experimental research on rats recently, we completed the operation by transmastoid approach for removal of facial neuroma, and the gap of the nerve was repaired with muscle autograft denatured by microwave. RESULTS: The patient was followed up for one year, and her facial function recovery on the affected side was satisfactory. CONCLUSION: Muscle autograft denatured by microwave technique is convenient, highly efficient for repairing facial nerve gap after removal of facial neuroma.

Adult↗
PubMedDate not supplied

Distribution of apolipoprotein E allele frequencies of the Han Chinese in an iodine-deficient mountainous area.

BACKGROUND: Iodine deficiency is common in the Qinba mountainous area and fetal iodine deficiency disorder (FIDD) is endemic. Our previous study demonstrated that apolipoprotein E (ApoE) was a genetic risk factor for FIDD in the local area. AIM: In order to achieve a better understanding of the aetiology of iodine deficiency-based mental retardation in the Qinba mountainous area, we conducted further studies of ApoE allele frequencies obtained from the local population. SUBJECTS AND METHODS: A total of 818 samples from four counties in the iodine-deficient area were recruited for the study of the ApoE genotype and allele frequencies using the PCR-RFLP method, and were subsequently confirmed by sequencing. RESULTS: The frequencies of epsilon2, epsilon3 and epsilon4 alleles of Han Chinese in Qinba were 9.67%, 81.30% and 9.03%, respectively. Furthermore, no significant differences in the distribution of ApoE (either genotype or allele frequencies) between any two subgroups divided according to location, sex and age (p > 0.05) were found. Surprisingly, however, we found a significant difference in the genotype and allele frequencies between Qinba and Shanghai (genotype: chi2 = 14.91, p = 0.0096; allele: chi2 = 15.07, p = 0.0009). CONCLUSION: The currently documented allele frequencies of ApoE in the Han Chinese population living in the open areas of China do not represent the distribution in the isolated Qinba mountainous area. The higher level of epsilon2 and epsilon4 allele frequencies in the Han Chinese living in the isolated Qinba area arise by chance or may result from genetic adaptation to an environment characterized by malnutrition and iodine deficiency, which may also contribute to the high incidence of mental retardation in these regions.

Adolescent↗
PubMedDate not supplied

Genetic and biochemical studies of the Agouti-attractin system.

Pleiotropic effects of melanocortin signaling were first described nearly 100 years ago when mice carrying the lethal yellow (A(y)) allele of the Agouti coat color gene were recognized to develop increased growth and adiposity. Work from our laboratory and others over the last several years has demonstrated that the non-pigmentary effects of A(y) are caused by ectopic expression of Agouti protein, a paracrine signaling molecule whose normal function is to inhibit signaling through the melanocortin 1 receptor (Mc1r), but which can mimic the effects of Agouti-related protein (Agrp), a homologous neuropeptide produced in the medial portion of the arcuate nucleus that acts as a potent antagonist of the Mc3r and Mc4r. Recently we have used the genetics of pigmentation as an in vivo screening system to analyze other mutations in the Agouti-melanocortin pathway, leading to the identification of Attractin (Atrn), a widely expressed type I transmembrane protein that serves as an accessory receptor for Agouti protein. Surprisingly, homologs of Atrn are found in fruitflies and nematodes, even though Agouti and/or Agouti-related protein are found only in vertebrates. Insight into this apparent paradox now comes from studies of different Atrn alleles, in which we find hyperactivity, abnormal myelination, and widespread CNS vacuolation. We suggest that the neurodegenerative phenotype reflects the ancestral function of Atrn to facilitate and/or maintain cell-cell interactions in the nervous system. Expression in neurectodermal cells during vertebrate evolution may have allowed Atrn to be recruited by the Agouti-melanocortin system to control coat color.

Agouti Signaling Protein↗