Biomedical subjects
Publications and source records attributed to Yun He.
A series of novel benzimidazoles were efficiently synthesized using both solution- and solid-phase chemistry. These compounds were found to bind to the bacterial 16S ribosomal RNA A-site with micromolar affinities using unique mass spectrometry-based assays.
OBJECTIVE: To investigate the frequency of numerical aberrations for chromosomes 7 and 8 in the sperms of workers exposed to benzene series. METHODS: Numerical aberrations in the sperms of workers were detected by two-color fluorescence in situ hybridization with biotin labeled chromosome 7 probe (D7Z1) and digoxingenin labeled chromosome 8 probe (D8Z1). RESULTS: The time-weight average air concentration (TWA) of benzene in the workshop was 42.29 mg/m(3), which was significantly higher than that of the national maximum allowable concentration [6 mg/m(3)]. The concentration of urinary trans,trans-muconic acid(ttMA) in the exposed group was also higher than that of the control group. In all, 155721 sperm nuclei from 15 workers in the exposed group and 123771 sperm nuclei from 12 individuals in the control group were examined. The results showed that the frequency of diploidy sperms and the frequencies of disomic sperm for chromosomes 7 and 8 in the exposed group (0.129%, 0.170%, 0.078%) were significantly higher than those of the control group (0.055%, 0.053%, 0.033%), respectively. The frequencies of nullisomic sperm for chromosomes 7 and 8 in the exposed group (0.165%, 0.088%) were also significantly increased, compared with those of the control group (0.056%, 0.029%). A statistically significant difference in the frequency of overall numerical chromosome aberrations was seen between the exposed group (0.745%) and the control group (0.289%). CONCLUSION: The results suggested that higher concentration of benzene may induce higher frequencies of numerical aberrations in the sperms of workers exposed to benzene series.
A library of linked molecules were synthesized from the common sugar moieties existing in the natural amino glycosides. These linked molecules were screened against bacterial 16S RNA for their binding affinity using a mass spectrometry-based technology. Some of these compounds exhibited low micromolar affinity and could serve as leads for further development as antibacterial agents.
A series of 2-piperidin-4-yl-benzimidazoles were synthesized and evaluated for antibacterial activities. Certain compounds inhibit bacterial growth with low micromolar minimal inhibitory concentration (MIC). These benzimidazoles are effective against both Gram-positive and Gram-negative bacteria of clinical importance, particularly enterococci, and represent a new class of potential antibacterial agents.
OBJECTIVE: To study hMSH2 genetic polymorphism in southern Chinese Han population. METHODS: The basic materials and blood samples from 163 southern Chinese were collected. The mutations of exon 6 and exon 7 of hMSH2 gene were investigated by PCR-SSCP, followed by DNA sequencing. RESULTS: Fragments of 250 bp including exon 6 and fragments of 323 bp including exon 7 of hMSH2 gene were amplified by multiple PCR. The allele frequencies of C18, A82 and B39 type mutations were 0.0184, 0.0031, 0.0031, respectively. The gene frequencies and gene type frequencies of three polymorphism sites in normal population accorded with Hardy-Weinberg equilibrium (P>0.05). The heterozygosity of C18 type mutation (0.0361) was the highest. CONCLUSION: There were three polymorphism sites in exon 7 of hMSH2 gene in southern Chinese Han population, among which the genotype frequency of C18 type was the highest, suggesting that C18 type mutation be a useful genetic mark.
OBJECTIVE: To study DNA and nucleus damage in human embryo lung fibroblast (HLF) exposed to hydroquinone (HQ) and its genotoxicity. METHODS: HLF were treated with HQ (0, 10, 20, 40, 80 micro mol/L, respectively) for 3 h and DNA damage was detected by comet assay. HLF was also treated with the same concentrations of HQ for 1 h and micronucleus test was performed after they were cultured for 24 h. RESULTS: Comet assay showed that percentage of cells with tails in each groups treated with varied doses of HQ was 12%, 19%, 42%, 79% and 95%, respectively, with mean tail length of 7.87, 9.35, 11.03, 19.28 and 23.32 micro m, respectively, in an obvious dose-dependent manner (P < 0.05). Very significant increase in percentage of cells with tails and length of their comet tail were observed in those groups treated with HQ of 20, 40 and 80 micro mol/L (P < 0.01). And, proportion of high and severe DNA damage increased with dose of HQ. HQ could also induce formation of micronucleus and abnormal nucleus in all groups treated by varied doses of HQ, with rates of micronucleus and abnormal nucleus of 2%, 3%, 10%, 9% and 15%, and 6%, 7%, 16%, 27% and 28%, respectively, in a significant dose-dependent manner. There was significant increase in rates of micronuclei and abnormal nuclei in cells treated with HQ at doses of 20, 40 and 80 micro mol/L (P < 0.05). CONCLUSIONS: Exposure to HQ could cause DNA and nucleus damage inducing genotoxic effects on HLF.
OBJECTIVE: To construct DNA double-strand break (DSB) repair protein hKu70 deficient cell strain and to observe its biological characters for studying the functions of hKu70 gene and the effects of occupational harmfulness factors on DSB repair. METHODS: Human lung fibroblasts (HLF) were transfected with the eukaryotic expression plasmids of hKu70 gene antisense RNA (pEGFP-C1-K) to construct hKu70 protein deficient cells (named as "HLFK"). The protein expression levels of hKu70 gene in HLFC and HLFK were detected by the Western blotting to estimate the effects of antisense inhibition. Morphology, growth character and growth status in soft agar of transfected HLFK were observed. RESULTS: pEGFP-C1-K vector was successfully expressed in HLF. The protein expression level of hKu70 gene in HLFK was decreased by 42% as compared with that in HLFC. No obvious changes of the biologic characters were observed in HLFK. CONCLUSION: The hKu70 protein deficient cell strain was successfully constructed. The hKu70 protein deficiency alone didn't induce obvious changes of the biological characters in HLFK.
OBJECTIVE: To construct pEGFP-C1-T vector, an eukaryotic expression plasmid of hMTH1 gene antisense RNA. METHODS: The conservative region of hMTH1 gene was amplified by RT-PCR after total RNA being extracted from human embryo lung fibroblast (HLF) and then cloned into pGEM-T vector. After the recombinant plasmid was certified by DNA sequencing, the conservative region of hMTH1 gene was inserted into pEGFP-C1 vector reversedly and pEGFP-C1-T vector was constructed. The efficiency of antisense inhibition was verified by Western blotting after cell transfection. RESULTS: 423 bp fragment including conservative region of hMTH1 gene was obtained by RT-PCR. After cloned by pGEM-T vector and certified by DNA sequencing, pEGFP-C1-T vector was successfully constructed by means of recombinant DNA technology. Additionally pEGFP-C1-T vector could efficiently decrease hMTH1 protein level by 46%. CONCLUSION: The efficient expression vector of hMTH1 gene antisense RNA, pEGFP-C1-T has been constructed successfully.
The degradation of neomycin B was reexamined, and a novel protocol was established to prepare the properly masked neomycin CD ring as a glycol donor in excellent yield. Glycosylation of the CD ring with glycol acceptors provided a facile access to versatile intermediates that could be utilized to synthesize a variety of novel neomycin B mimetics for RNA recognition. [reaction: see text]
OBJECTIVE: To report our experience in diagnosis and treatment of AIDS complicated by Pneumocystis Carinii Pneumonia (PCP), and explore the relations between preventive medication and occurrence as well as recurrence of PCP. METHODS: The clinical characteristics of 20 patients with AIDS complicated by PCP (identified from a cohort of 109 patients with AIDS) treated in our hospital during July 2000 to May 2002 were analyzed. RESULTS: All the 20 cases had fever, 90 % of whom also had cough or expectoration, and chest radiography revealed bilateral interstitial changes in 80 % of the cases. CONCLUSION: It is possible to diagnose PCP by typical clinical findings and chest X-ray, and compound sulfamethoxazole may prove effective for preventing the occurrence of PCP.
Explore the source record for details and available documents.
High-throughput screening (HTS) campaigns in pharmaceutical companies have accumulated a large amount of data for several million compounds over a couple of hundred assays. Despite the general awareness that rich information is hidden inside the vast amount of data, little has been reported for a systematic data mining method that can reliably extract relevant knowledge of interest for chemists and biologists. We developed a data mining approach based on an algorithm called ontology-based pattern identification (OPI) and applied it to our in-house HTS database. We identified nearly 1500 scaffold families with statistically significant structure-HTS activity profile relationships. Among them, dozens of scaffolds were characterized as leading to artifactual results stemming from the screening technology employed, such as assay format and/or readout. Four types of compound scaffolds can be characterized based on this data mining effort: tumor cytotoxic, general toxic, potential reporter gene assay artifact, and target family specific. The OPI-based data mining approach can reliably identify compounds that are not only structurally similar but also share statistically significant biological activity profiles. Statistical tests such as Kruskal-Wallis test and analysis of variance (ANOVA) can then be applied to the discovered scaffolds for effective assignment of relevant biological information. The scaffolds identified by our HTS data mining efforts are an invaluable resource for designing SAR-robust diversity libraries, generating in silico biological annotations of compounds on a scaffold basis, and providing novel target family specific scaffolds for focused compound library design.