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Biomedical subjects

Lei Jin

Publications and source records attributed to Lei Jin.

At least 55 records · Page 3Linked to original sources
PubMed2004

[Characterization of peripheral dendritic cell subsets and its implication in patients infected with severe acute respiratory syndrome].

OBJECTIVE: To investigate the dynamic changes of dendritic cell subsets in peripheral blood of patients infected with severe acute respiratory syndrome (SARS) and evaluate their roles in the immunopathogenesis of SARS. METHODS: Flow cytometry was applied to study the dynamic alteration of the number and frequencies in circulating DC cell subsets in 30 SARS patients including critical SARS (n = 11) and general SARS (n = 19). The reasons and clinic significances of the peripheral blood DC subsets changes in SARS patients were also analyzed in our study. RESULTS: The patients in critical status had a 9-week course of disease, longer than the 6-week course observed in subjects in general status. The frequency of peripheral DC cell subsets significantly dropped beginning from the onset of symptom in SARS patients and was maintained at significant low levels during the following 4 - 5 weeks, 1.7 +/- 1.8, 5.3 +/- 5.0/ micro l for DC1, 0.57 +/- 1.02, 0.98 +/- 1.11/ micro l for DC2 for cases in critical and general statuses, respectively, compared with healthy subjects; more importantly, the pDC2 even disappeared in the patients who died from SARS diseases. The possible reasons responsible for the alteration of DC subsets in peripheral blood is likely to be the direct attack of SARS-CoVin circulation and be partially involved the application of large dose of steroid. The frequency in DC cell subsets returned to normal level in convalescent stage. CONCLUSION: Our results showed SARS patients had a significant decrease of circulating DC cell subset frequency, which maybe lead to the host immunodeficiency response to SARS-associated coronavirus (SARS-CoV).

Adult↗
PubMed2004

Sensitivity of second harmonic generation from styryl dyes to transmembrane potential.

In this article we present results from the simultaneous nonlinear (second harmonic generation and two-photon excitation fluorescence) imaging and voltage clamping of living cells. Specifically, we determine the sensitivity to transmembrane potential of second harmonic generation by ANEP-chromophore styryl dyes as a function of excitation wavelength and dye structure. We have measured second harmonic sensitivities of up to 43% per 100 mV, more than a factor of four better than the nominal voltage sensitivity of the dyes under "one-photon" fluorescence. We find a dependence of voltage sensitivity on excitation wavelength that is consistent with a two-photon resonance, and there is a significant dependence of voltage sensitivity on the structure of the nonchromophore portion of the dyes.

Animals↗
PubMed2004

Polymorphisms of the PRNP gene in Chinese populations and the identification of a novel insertion mutation.

The two common polymorphisms (385A > G: M129V and 655G > A: E219 K) in the human prion gene (PRNP) play important roles in the pathogenesis of Creutzfeldt-Jakob diseases. We screened a total of 626 individuals, who represent three ethnic populations of China, Han, Hui, and Uyghur, for the two polymorphisms. The frequencies of M/M homozygote at residue 129 in these three groups differ significantly. The Han has a much higher frequency (98%) than Hui (85%) and Uyghur (60%). On the other hand, the frequencies of the E/E at residue 219 are higher in Uyghur (98%) and Hui (96%) than in Han (90%). We also investigated two other less common variants of PRNP, a silent substitution at residue 117 (351A > G: A117A), and one octapeptide-repeat deletion (1-OPRD) in the octapeptide-coding region. We found three Uyghur individuals with silent substitution at residue 117. Four Hui (2.0%) and one Han (0.5%) donors were found to be heterozygous for 1-OPRD. A novel three extra-repeat (72 bp) insertion within the octapeptide-coding region was identified in one healthy 11-years-old Hui. Identical mutation was also found in her mother but not her father.

Amyloid↗
PubMed2004

Transcriptional downregulation of DC-SIGN in human herpesvirus 6-infected dendritic cells.

DC-SIGN expressed on dendritic cells (DCs) efficiently binds and transmits various pathogens, including human immunodeficiency virus, to lymphoid tissues and permissive cells. Consequently, alteration of DC-SIGN expression may affect susceptibility and resistance to pathogens. The present study shows that infection with human herpesvirus 6 (HHV-6) induces downregulation of DC-SIGN expression on immature DCs. Expression levels of DC-SIGN mRNA and intracellular protein appeared to decrease following infection with HHV-6, indicating that downregulation of surface DC-SIGN occurs at the transcriptional level. Downregulation of DC-SIGN was not induced by inoculation of UV-inactivated HHV-6 or culture supernatant of HHV-6-infected DCs, indicating that replication of HHV-6 in DCs is required for downregulation of DC-SIGN. The present study demonstrates for the first time that expression of DC-SIGN is altered at the transcriptional level by virus infection.

Cell Adhesion Molecules↗
PubMed2004

Improving diabetes care in midwest community health centers with the health disparities collaborative.

OBJECTIVE: To evaluate the Diabetes Health Disparities Collaborative, an initiative by the Bureau of Primary Health Care to reduce health disparities and improve the quality of diabetes care in community health centers. RESEARCH DESIGN AND METHODS: One year before- after trial. Beginning in 1998, 19 Midwestern health centers undertook a diabetes quality improvement initiative based on a model including rapid Plan-Do-Study-Act cycles from the continuous quality improvement field; a Chronic Care Model emphasizing patient self-management, delivery system redesign, decision support, clinical information systems, leadership, health system organization, and community outreach; and collaborative learning sessions. We reviewed charts of 969 random adults for American Diabetes Association standards, surveyed 79 diabetes quality improvement team members, and performed qualitative interviews. RESULTS: The performance of several key processes of care assessed by chart review increased, including rates of HbA(1c) measurement (80-90%; adjusted odds ratio 2.1, 95% CI 1.6-2.8), eye examination referral (36-47%; 1.6, 1.1-2.3), foot examination (40-64%; 2.7, 1.8-4.1), and lipid assessment (55-66%; 1.6, 1.1-2.3). Mean value of HbA(1c) tended to improve (8.5-8.3%; difference -0.2, 95% CI -0.4 to 0.03). Over 90% of survey respondents stated that the Diabetes Collaborative was worth the effort and was successful. Major challenges included needing more time and resources, initial difficulty developing computerized patient registries, team and staff turnover, and occasional need for more support by senior management. CONCLUSIONS: The Health Disparities Collaborative improved diabetes care in health centers in 1 year.

Community Health Centers↗
PubMed2004

Genetic variation of SARS coronavirus in Beijing Hospital.

To characterize genetic variation of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) transmitted in the Beijing area during the epidemic outbreak of 2003, we sequenced 29 full-length S genes of SARS-CoV from 20 hospitalized SARS patients on our unit, the Beijing 302 Hospital. Viral RNA templates for the S-gene amplification were directly extracted from raw clinical samples, including plasma, throat swab, sputum, and stool, during the course of the epidemic in the Beijing area. We used a TA-cloning assay with direct analysis of nested reverse transcription-polymerase chain reaction products in sequence. One hundred thirteen sequence variations with nine recurrent variant sites were identified in analyzed S-gene sequences compared with the BJ01 strain of SARS-CoV. Among them, eight variant sites were, we think, the first documented. Our findings demonstrate the coexistence of S-gene sequences with and without substitutions (compared to BJ01) in samples analyzed from some patients.

Adult↗
PubMed2004

[Delivery after cryopreservation of percutaneous epididymal sperm aspiration specimens and intracytoplasmic sperm injection: 1 case report].

Intracytoplasmic sperm injection (ICSI) with sperm collected by percutaneous epididymal sperm aspiration (PESA) technique is nowadays the main treatment for obstructive azoospermia(OAS). To cryopreserve the epididymal sperm obstained by PESA can avoid repeat retrievals. We transferred the embryos fertilized by ICSI with frozen/thawed epididymal sperm and achieved a delivery, which shows that epididymal sperm obstained by PESA can be successfully cryopreserved.

Adult↗
PubMed2003

An asymmetric NFAT1 dimer on a pseudo-palindromic kappa B-like DNA site.

The crystal structure of the NFAT1 Rel homology region (RHR) bound to a pseudo-palindromic DNA site reveals an asymmetric dimer interaction between the RHR-C domains, unrelated to the contact seen in Rel dimers such as NF kappa B. Binding studies with a form of the NFAT1 RHR defective in the dimer contact show loss of cooperativity and demonstrate that the same interaction is present in solution. The structure we have determined may correspond to a functional NFAT binding mode at palindromic sites of genes induced during the anergic response to weak TCR signaling.

DNA↗
PubMed2003

Direct measurement of the voltage sensitivity of second-harmonic generation from a membrane dye in patch-clamped cells.

We report what is to our knowledge the first optical imaging of voltage-clamped cells by second-harmonic generation. For the membrane-staining styryl dye di-4-ANEPPS, we determined the sensitivity of second-harmonic generation to be 18%/100 mV at an excitation wavelength of 850 ns. This sensitivity is significantly better than the optimal 10%/100 mV under fluorescence and further establishes the importance of second-harmonic generation for the functional imaging of membrane potential in living cells.

Animals↗
PubMed2003

Afterpulsing and its correction in fluorescence correlation spectroscopy experiments.

Afterpulsing arises from feedback in a photon detector. This means that each real signal pulse can be followed by an afterpulse at a later time. This effect is particularly troubling in photon correlation experiments. Few treatments of this effect have appeared in the literature, and few software programs to solve the problem have been written. We demonstrate the afterpulsing effect in fluorescence correlation spectroscopy by using different avalanche photodiodes. We prove theoretically that under simple and reasonable conditions afterpulsing in autocorrelation can be eliminated to the leading order; we have found it easy to program software for the correction. We compare our results with those from cross correlation. We also discuss some experimental parameters that may affect the afterpulsing.

Journal Article↗
PubMed2003

Population survey of CCR5 delta32, CCR5 m303, CCR2b 64I, and SDF1 3'A allele frequencies in indigenous Chinese healthy individuals, and in HIV-1-infected and HIV-1-uninfected individuals in HIV-1 risk groups.

The aim of this study is to determine in indigenous Chinese ethnic groups the frequencies of the chemokine (SDF1 3'A) and chemokine receptors (CCR5 delta32, CCR5 m303, and CCR2b 64I) HIV-1/AIDS restriction alleles. The study includes two cohorts; the first comprised 3165 indigenous healthy subjects representing eight ethnic groups: Han (n = 1406), Uygur (n = 316), Mongolia (n = 134), Hui (n = 386), Tibetan (n = 330), Zhuang (n = 378), Dai (n = 101), and Jingbo (n =114). The second cohort consisted of 330 HIV-1-infected (86 subjects infected by sexual transmission and 198 subjects infected by HIV-1-contaminated blood or by sharing injection equipment; the remaining 46 subjects said nothing about HIV-1 transmission) and 474 HIV-1-uninfected Han Chinese belonging to one of two HIV-1 high-risk groups: intravenous drug users (n = 215) and individuals with sexually transmitted diseases (n = 259). Genotypes for the four genes were obtained using PCR (CCR5 delta32) or PCR-restriction fragment length polymorphism. Randomly selected amplified PCR products were further confirmed by direct DNA sequencing. The variant allele frequencies were determined to be 0% to 3.48% for CCR5 delta32, 0% for CCR5 m303, 16.23% to 28.79% for CCR2b 64I, and 17.70% to 27.76% for SDF1 3'A in Chinese healthy individuals from eight ethnic groups. These findings show that allele frequencies differ among the eight Chinese ethnic groups for CCR5 delta32, CCR2b 64I, and SDF1 3'A and that the CCR5 m303 and CCR5 delta32 mutant alleles were absent or infrequent in Chinese, which may be helpful for studies of specific anti-HIV-1 vaccine trials and coreceptor inhibitor drug targets in Chinese populations. Furthermore, we observed no significant differences in allele or genotypic frequencies between HIV-1-infected and HIV-1-uninfected groups from the Han ethnic group. Our finding is the first reporting that there is likely no effect of the examined polymorphisms in our study on HIV-1 transmission in the Chinese Han population, However, the genetic effects of these and other AIDS-modifying polymorphisms on the pathogenesis and clinical outcome of HIV-1/AIDS diseases is under investigation in Chinese populations.

Adult↗
PubMed2003

[Single nucleotide polymorphism loci of HIV-1 coreceptor CCR5 gene in Chinese Han people].

OBJECTIVE: To investigate the single nucleotide polymorphism(SNP) loci of HIV-1 coreceptor CCR5 gene in Chinese Han people. METHODS: The coding region of CCR5 was amplified using 2 pairs of primers and the PCR products of all 42 healthy subjects were sequenced by 4 different primers. The results of sequencing were analyzed by DNAstar in search of SNP loci. RESULTS: Six SNP loci were discovered in the coding region of CCR5, among them four SNPs, i.e. 184A-->G, 503G-->T, 688G-->A and 999G-->T, cause amino acids changes and two SNPs are nonsense mutations. One cytosine deletion at the 894nt results in frame shift mutation and prematured termination. 184A-->G, 503G-->T and 999G-->T were found in Chinese Han people for the first time. The allelic frequencies of mutant 184G, 503T and 999T alleles were 1.1%, 21.1% and 10.0% in healthy Hans, respectively. The population distribution of G503T markedly deviated from Hardy-Weinberg equilibrium. CONCLUSION: The SNP loci in the coding region of CCR5 in Chinese Han people has its own characteristics, which is not consistent with those of Japanese and obviously different from those of Caucasian and African.

Adult↗
PubMed2003

[Analysis on landscape pattern in the Tuoketuo region of Inner Mongolia].

The Tuoketuo region is located in the middle reach of Yellow River, farming-pastoral zone in Inner Mongolia. In this paper, the vegetation map of study area was compiled by combining TM image and field vegetation survey. Applying several landscape pattern indices such patch size, number, perimeter density, diversity index, evenness index and fragmentation index etc., the landscape pattern of the Tuoketuo region was analyzed on a GIS platform. The result showed that the landscape types in Tuoketuo region mainly consisted of farmland, artificial forest and grassland. The area of farmland was 281.72 km2 and accounted for 33.64% of study region, artificial forest was 22.0%, and grassland was 6.65%. The landscape matrix in northeast part of study area was farmland. On the farmland matrix, Populus + Ulmus patches distributed with centering of residential spot, there were 89 patches. The patch density was 2.568 patch.km-2, and the mean patch area of Populus + Ulmus was only 0.39 km2, therefore, the characteristics of matrix and patch was very typical. Perimeter density of Populus + Ulmus and hill-gully were higher than other landscape types, indicating that the fragmentation degree of the former was higher, and hill-gulf was cut seriously in study area. All of these results emphasize that human activity had a strong impact on the landscape pattern in the Tuoketuo region.

Agriculture↗
PubMed2003

[Polymorphisms of six short tandem repeat loci in Zhejiang She ethnic population and Zhejiang Hans of China].

OBJECTIVE: To investigate genetic polymorphism of six short tandem repeat (STR) loci (D3S1358,D16S539, TH01,TPOX, CSF1PO,D7S820) in Zhejiang She ethnic population and Han population. METHODS: By use of AmpFlSTR Cofiler kit, 6 STR loci in 108 She samples and 102 Han samples were amplified. The PCR products were electrophoresed by ABI Prism 377 sequencer; the data were analyzed by Genescan software. RESULTS: All genotype frequencies of the 6 STR loci in She and Han ethnic groups met Hardy-Weinberg equilibrium. In the She population, the heterozygosities (H) in D3S1358,D16S539,TH01,TPOX, CSF1PO and D7S820 were 0.8028, 0.9148, 0.7522, 0.6728, 0.9123,0.8338, the exclusion of paternity(EP) were 0.4067, 0.6057, 0.4437, 0.3200, 0.5250, 0.5358, discrimination power (DP) were 0.6690, 0.7841, 0.6447, 0.5382, 0.7298, 0.7296.The combined DP, PE and polymorphism information content were 0.9991,0.9805,0.9988 respectively. There were significant differences at D3S1358, D16S539 and TPOX loci, compared with Hans. CONCLUSION: She population has its own STR allele distribution characteristic. The above data obtained from She population can be used not only in genetic researches and population investigation, but also in human identity and paternity testing.

China↗
PubMed2003

[Polymorphism of CXCR4 coding region of human immunodeficiency virus-1 in Chinese Han people].

OBJECTIVE: To study the polymorphism of human immunodeficiency virus (HIV)-1 coreceptor CXCR4 in Chinese Han ethnic group for AIDS prevention and treatment. METHODS: Totally 48 individuals were enrolled into the study. CXCR4 (cDNA No-AF147204) was cloned by PCR amplification using 2 pairs of primers, then sequenced using sequencing primers. The results of the same sequencing primers were analyzed by DNAstar software to find and identify single nucleotide polymorphism (SNP) sites. RESULTS: Totally 7 SNPs were found in the coding region of CXCR4, among them 3 were synonymous mutation (C-->T at loci 129, 426 and 968), 3 were missense mutation (C-->T at locus 38, A-->T at locus 90, and A-->C at locus 712) and 1 was stop mutation (C-->T at 106, which converted the codon for glutamic acid into stop codon). CONCLUSIONS: The polymorphism of CXCR4 coding region in Chinese Han is probably different from that of the other ethnic groups. Six of the 7 SNPs were discovered for the first time. Their influences on AIDS progression are worthy of studying.

Adult↗
PubMed2003

[Distribution of HIV-1 coreceptor CX3CR1 allelic polymorphisms in general population, HIV-1 high-risk group and HIV-1 carriers of Chinese indigenous Han and Uygur people].

OBJECTIVE: To investigate the V249I and T280M allelic polymorphisms of human immunodeficiency virus (HIV) coreceptor CX3CR1 in HIV-1 infected and uninfected population of Chinese indigenous Han and Uygur people and to probe the association between I249-M280 haplotype and HIV-1 susceptibility as well as AIDS progression. METHODS: Genomic DNA of 223 Uygur subjects and 316 Han subjects were purified from PBMC. I249 and M280 allelic frequencies were identified by polymerase chain reaction (PCR)/nest polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. All data were tested by chi(2) or u statistics analysis. RESULTS: Allelic frequencies of I249 and M280 were 16.1% and 13.3% in Uygur people, and 3.3% and 2.4% in Han people. No obvious difference existed between three groups of either ethnic group. However the allelic frequencies of HIV infected population were higher than those of general population, and those of general population higher than those of HIV-1 high-risk group. There was a strong linkage between I249 and M280 (P almost zero). CONCLUSIONS: I249 mutation was the sine qua non of M280 mutation, and most I249 alleles were accompanied by M280. The frequency of I249-M280 haplotype in Uygur population (13.3%) was adjacent to Caucasian people (15.8%), and that of I249-T280 haplotype (2.8%) was obviously lower than Caucasian people (12.5%); while both of them in Han people were much lower (0.9% and 2.4%). I249-M280 haplotype could accelerate AIDS progression according to Faure et al, while might be associated with HIV-1 susceptibility.

Alleles↗
PubMed2003

[Preliminary study on the association of chemokine RANTES gene polymorphisms with HIV-1 infection in Chinese Han population].

OBJECTIVE: To detect the single nucleotide polymorphism (SNP) of chemokine regulated upon activation, normal T cell expressed and secreted (RANTES) promoter and first intron of asymptomatic, human immunodeficiency virus 1 (HIV-1) infected individuals of in Han Chinese and evaluate the influence on HIV-1 infection by variants. METHODS: Case-control study was adopted, Genotypes of RANTES promoter -403 and -28 from 538 samples and RANTES first intron In1.1 from 300 samples of Han Chinese were detected by DNA sequencing or by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: There were six genotypes of RANTES promoter -403 and -28 found in Han Chinese group. The distribution of genotypes was AC/AC 12.4%, AC/AG 3.5%, AC/GC 29.2%, AG/GC 10.9%, GC/GC 42.1%, AG/AG 1.5%. The haplotypes was GC 62.7%, AC 28.7%, AG 8.6%. Compared with AC/AC, Odd ratio (OR) of RANTES genotypes AC/AG, AC/GC, AG/GC, GC/GC was associated with weaker reduced susceptibility to HIV-1 infection. However, there were no significant contents of the allele frequencies between people living with HIV-1 and healthy individuals. The distribution of RANTES In1.1 alleles were T/T 71.0%, C/T 19.9%, C/C 9.1% and haplotypes were RANTES In1.1T 81%, In1.1C 19%, respectively; There were significant differences of RANTES In1.1 between people with HIV-1 infection and healthy individuals in males. The In1.1C-bearing genotypes would increase susceptibility to HIV-1 infection but no significant differences in females were found. Strong linkage disequilibrium was observed between all of the three RANTES SNPs. CONCLUSION: The two -403A/G, -28C/G variants in RANTES promoter region and intron In1.1 T/C mutation genotype were found to be associated with the genetic susceptibility to HIV-1 infection among the Han Chinese. However, the In1.1C allele or its haplotypes in RANTES intron 1 displayed a stronger dominant association with HIV-1 infection in males.

Adolescent↗