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Biomedical subjects

B Tang

Publications and source records attributed to B Tang.

At least 37 records · Page 2Linked to original sources

[PCR in the gene diagnosis of Charcot-Marie-Tooth disease].

OBJECTIVE: To establish the gene diagnosis of chavcot-Marie-Tooth disease (CMT) by (PCR) polymerase chain reaction and to study the molecular genetic characteristics of the Chinese CMT. METHODS: Mutation analysis of the Cx32, MPZ and PMP22 genes were performed by PCR-RFLP, PCR-SSCP, PCR-DGGE and/or direct sequencing in 32 CMT probands of the Hans in China. RESULTS: 21.9% of the CMT pedigrees had mutations in the Cx32, MPZ and PMP22 genes. Ten kinds of abnormal bands were found by PCR-SSCP, including 5 kinds of polymorphism and 5 point mutations in the exons of the gene (4 of the Cx32 and 1 of the MPZ). No point mutation of the PMP22 gene was found in these patients but two families (6.3%) were diagnosed as CMT1A by the PCR-RFLP, with the tandem repeat mutation of 1.5 Mb including the PMP22 gene. CONCLUSION: PCR-SSCP and PCR-RFLP are the first two screening methods in the gene diagnosis of CMT. PCR-DGGE is not appropriate for mutation analysis of Cx32. The point mutations must be certificated by sequencing. The mutation screening in the possible X-linkage family has to start with Cx32 gene.

Charcot-Marie-Tooth Disease↗

Study on fluorescent property of degrading products of piperacillin and its analytical application.

The fluorimetric property of the degrading products of piperacillin has been studied in detail. The studies on degrading pH, degrading time, detection alkalinity and other corresponding analytical parameters of acid degradation have been made. Then fluorometry of piperacillin was established by producing its stable fluorescent products. The detection limit for acid degradation analytical method is 2.34 ng/ml, the linear range is 7.80-4.0 x 10(2) ppb. The analytical sensitivity, precision and stability of degrading products of acid degradation are satisfactory, which has been used for the determination of the trace piperacillin in human serum and urine with satisfactory results.

Humans↗

Thought disorder in attention-deficit hyperactivity disorder.

OBJECTIVE: This study compared thought disorder and associated cognitive variables in attention-deficit hyperactivity disorder (ADHD) and schizophrenia. METHOD: Speech samples of 115 ADHD, 88 schizophrenic, and 190 normal children, aged 8 to 15 years, were coded for thought disorder. A structured psychiatric interview, the WISC-R, the Continuous Performance Test, and the Span of Apprehension task were administered to each child. RESULTS: The ADHD and schizophrenic groups had thought disorder compared with the normal children. However, the subjects with ADHD had a narrower range of less severe thought disorder than did the schizophrenic subjects. The younger children with ADHD and schizophrenia had significantly more thought disorder than did the older children with these diagnoses. IQ, attention, and working memory were associated with thought disorder in the ADHD but not the schizophrenic group. CONCLUSIONS: Thought disorder in childhood is not specific to schizophrenia and reflects impaired development of children's communication skills.

Adolescent↗

[X-linked recessive Charcot-Marie-Tooth disease and Cx32 gene mutation].

OBJECTIVE: To study the Cx32 gene mutation in a X-linked recessive Charcot-Marie-Tooth disease (CMTXR) family. METHODS: Mutation analysis of Cx32 was screened by polymerase chain reaction single strand conformation polymorphism (PCR-SSCP) combined with DNA direct sequencing in 4 patients, 9 unaffected family members and 50 unrelated normal individuals. RESULTS: Arg15Gln mutation was found in 4 patients and 3 unaffected family members. CONCLUSION: The mutation of Cx32 can also cause CMTXR. Using PCR-SSCP combined with DNA direct sequencing can make gene diagnosis to CMTXR that is caused by Cx32 mutation.

Adult↗

[Direct determination of Pb, Zn and Cd in environmental and biological samples by FAAS].

This paper describes interference and background correction problem of direct determination of Pb, Zn and Cd in soil, sediment, plants, halobios and sea water by FAAS. With the improvement of limit of detection(L.O.D) of instrument, Pb, Zn and Cd in same environmental and biological samples can be analyzed directly by FAAS, but it is worth taking attention that there are quantities of elements which lead to background interference in air-ethyne flame, such as Al, Na, K Ca, Mg and Fe. Compare with no background correction, limit of detection using D2 lamp background correction is improved by 1.05-4.5 times, the recoveries and the relative standard deviation(R.S.D) are better, standard samples were also analyzed with satisfactory results.

Animals↗

[Analysis of the parkin gene deletion mutations in Chinese patients with Parkinson's disease].

OBJECTIVE: Clarify parkin gene deletion mutations at exons 3 to 7 in Chinese patients with Parkinson's disease (PD) and analyze them together with the clinical features of PD. METHODS: DNA was extracted from peripheral blood of 33 sporadic PD patients and 6 familial PD patients. Deletion mutations of parkin gene were identified by PCR amplification and agarose gel electrophoresis. The clinical data were analyzed together with the above information. RESULTS: Of the 33 sporadic PD patients, 1 had exons 5 and 7 deletion, 2 had exon 7 deletion. The age of onset was 46, 48, 50 respectively. In the 6 familial PD patients, 1 had exon 5 deletion. The inheritance pattern in this patient was autosomal recessive and onset of the patient was 60. All of the patients who had parkin gene deletion mutations had tremor, rigidity and bradykinesia, but athetosis was not found. In addition, deletion mutations of parkin gene at exons 3, 4 and 6, were not found. CONCLUSION: There are deletion mutations of parkin gene at exons 5 and 7 in Chinese PD patients.

Adolescent↗

Defects in methylthioadenosine phosphorylase are associated with but not responsible for methionine-dependent tumor cell growth.

A large proportion of human tumor-derived cell lines and primary tumor cells show methionine-dependent growth. This phenomenon refers to the ability of cells to grow in media containing methionine and the inability of cells to grow in media supplemented with methionine's precursor, homocysteine (Hcy). Methionine can be formed by two different pathways, the recycling pathway and the salvage pathway. To discover the basis for methionine-dependent growth, we have analyzed 12 tumor cell lines and 2 non-tumor-derived cell lines for defects in two key genes in different methionine synthetic pathways. We found little evidence that defects in methionine synthase expression or mutations in the MS gene are correlated with methionine-dependent growth. However, we did find a correlation between methionine-dependent growth and defects in expression of methylthioadenosine phosphorylase (MTAP), a key enzyme in the salvage pathway. Three of the four cell lines lacking detectable MTAP protein were unable to grow in Hcy-containing media, whereas all six of the MTAP-positive cell lines tested showed strong growth. However, when we introduced MTAP cDNA into MTAP-deficient MCF-7 cells, the resulting cell line was still defective in growth on Hcy, although it could now grow on the salvage pathway precursor methylthioadenosine. These findings indicate that salvage pathway defects are not causally related to methionine-dependent growth.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗

Antibody binding of deletion mutants of Asp f 2, the major Aspergillus fumigatus allergen.

Asp f 2, a 268 amino acid major allergen from Aspergillus fumigatus (Af) demonstrated nine linear IgE binding regions. It is not known whether any of these linear epitopes are also conformatory epitopes. Hence, we constructed deletion mutants of Asp f 2 devoid of one or more epitopes, and the IgE binding of these proteins with sera from patients with ABPA was compared with the full-length Asp f 2 expressed in E. coli and Pichia. The Pichia expressed protein reacted weakly with IgE, but strongly with IgG of ABPA sera compared to E. coli expressed Asp f 2. Weak IgE binding only was seen when the C-terminal or N-terminal was deleted, while depletion of both ends negated all reactivity. The monoclonal antibody IL-B8 and IgE and IgG of ABPA sera bound significantly to the Asp f 2 E-4 fragment indicating that the major B-cell epitope is located at the N-terminal end of Asp f 2.

Allergens↗

Immunogenicity and arthritogenicity of recombinant CB10 in B10.RIII mice.

Two major T cell determinants are recognized by I-Ar-specific T cells in CII, the immunodominant CII610-618 (GPAGT AGA R) within CB10 and the subdominant CII445-453 (GPAGP AGE R) within CB8. Although the determinants differ by only two residues, CB8 is capable of inducing collagen-induced arthritis (CIA), while CB10 is not. We, therefore, investigated the structural differences between the two determinants that are critical to inducing arthritis. When the CB10 determinant was mutated to that of CB8 using recombinant techniques, the resulting mutant rCB10T614P,A617E product became arthritogenic. Conversely, when the CB8 determinant was mutated to that of CB10, the resulting mutant CB8P449T,E452A was no longer arthritogenic. Comparison of the epitope specificity of the autoantibodies induced by wild-type CB10 and mutant rCB10T614P, A617E revealed no qualitative differences. T cells from mice immunized with either CB10 or mutant rCB10 produced predominantly Th1 cytokines when cultured with the immunizing Ag. In contrast, when cultured with mouse CII, T cells from mice immunized with the nonarthritogenic CB10 produced predominantly Th2 (IL-4 and IL-10) cytokines whereas the arthritogenic mutant rCB10 induced predominantly Th1 (IFN-gamma) cytokines. We conclude that the T cell cytokine response most critical for the induction of CIA is that induced against the corresponding homologous murine T cell determinant and, further, that the structural differences between the T cell determinants in CB8 and -10 are important in breaking self tolerance and inducing autoimmune response.

Animals↗

Frequency of SCA1, SCA2, SCA3/MJD, SCA6, SCA7, and DRPLA CAG trinucleotide repeat expansion in patients with hereditary spinocerebellar ataxia from Chinese kindreds.

OBJECTIVE: To assess the frequency of SCA1 (spinocerebellar ataxia type 1), SCA2, SCA3/MJD (spinocerebellar ataxia type 3/Machado-Joseph disease), SCA6, SCA7, and DRPLA (dentatorubropallidoluysian atrophy) CAG trinucleotide repeat expansions [(CAG)n] among persons diagnosed with hereditary SCA from Chinese families. PATIENTS AND METHODS: Spinocerebellar ataxia type 1, SCA2, SCA3/MJD, SCA6, SCA7, and DRPLA (CAG)n mutation were detected with the polymerase chain reaction, highly denaturing polyacrylamide gel electrophoresis, and silver staining technique in 167 patients with autosomal dominant SCA from 85 Chinese families and 37 patients with sporadic SCA. RESULTS: Spinocerebellar ataxia type 1 (CAG)n mutation in 7 patients from 4 kindreds (4.70%) was expanded to 53 to 62 repeats. Spinocerebellar ataxia type 2 (CAG)n mutation in 12 patients from 5 kindreds (5.88%) was expanded to 42 to 47 repeats. Spinocerebellar ataxia type 3/Machado-Joseph disease (CAG)n mutation in 83 patients from 41 kindreds (48.23%) was expanded to 68 to 83 repeats. Sixty-five patients from 35 kindreds (41.19%) and 37 patients with sporadic SCA did not test positive for SCA1, SCA2, SCA3/MJD, SCA6, SCA7, or DRPLA. There was a predictable inverse relationship between the number of CAG repeats and the age at onset for SCA3/MJD and SCA2. Clinically, dementia and hyporeflexia were more frequent in patients with SCA2, while spasticity, hyperreflexia, and Babinski signs were more frequent in patients with SCA3/ MJD, and those might be helpful in clinical work to primarily distinguish patients with SCA3/MJD and SCA2 from others with different types of SCA. CONCLUSIONS: The frequency of SCA3/MJD is substantially higher than that of SCA1 and SCA2 in patients with autosomal dominant SCA from Chinese kindreds, who are non-Portuguese. Clinical expressions of the various types of SCAs overlap one another; therefore, for clinical study it is important to make a gene diagnosis and genetic classification for patients with SCA.

Adolescent↗

Thought disorder in childhood schizophrenia: replication and update of concept.

OBJECTIVES: To examine whether measures of thought disorder differentiated schizophrenic from normal children and to examine the relationship of these measures with developmental and cognitive factors. METHOD: The speech samples of 88 schizophrenic and 190 normal children, aged 9 to 13 years, were coded with the Kiddie Formal Thought Disorder Rating Scale and Halliday and Hassan's analysis of cohesion. RESULTS: Above and beyond differences in mental age, gender, and neuroleptic status, the patients had significantly more formal thought disorder (FTD) and cohesive deficits than the normal children matched by mental age. The younger schizophrenic and normal children had significantly more thought disorder than the older children with these diagnoses. Combined FTD and cohesion scores correctly identified 76% of schizophrenic and 88% of normal children with little variability across mental age. The thought disorder measures generated 2 independent components: FTD and cohesion. CONCLUSIONS: Thought disorder measures that include both FTD and cohesion provide a quantitative diagnostic tool of childhood-onset schizophrenia.

Adolescent↗

Protective immunity to rotavirus shedding in the absence of interleukin-6: Th1 cells and immunoglobulin A develop normally.

We investigated whether interleukin-6 (IL-6) was required for the development of immunoglobulin A (IgA)- and T-helper 1 (Th1)-associated protective immune responses to rotavirus by using adult IL-6-deficient mice [BALB/c and (C57BL/6 x O1a)F(2) backgrounds]. Naive IL-6(-) mice had normal frequencies of IgA plasma cells in the gastrointestinal tract. Consistent with this, total levels of IgA in fecal extracts, saliva, and sera were unaltered. In specific response to oral infection with rhesus rotavirus, IL-6(-) and IL-6(+) mice exhibited efficient Th1-type gamma interferon responses in Peyer's patches with high levels of serum IgG2a and intestinal IgA. Although there was an increase in Th2-type IL-4 in CD4(+) T cells from IL-6(-) mice following restimulation with rotavirus antigen in the presence of irradiated antigen-presenting cells, unfractionated Peyer's patch cells failed to produce a significant increase in IL-4. Moreover, virus-specific IgG1 in serum was not significantly increased in IL-6(-) mice in comparison with IL-6(+) mice. Following oral inoculation with murine rotavirus, IL-6(-) and IL-6(+) mice mediated clearance of rotavirus and mounted a strong IgA response. When IL-6(-) and IL-6(+) mice [(C57BL/6 x O1a)F(2) background] were orally inoculated with rhesus rotavirus and later challenged with murine rotavirus, all of the mice maintained high levels of IgA in feces and were protected against reinfection. Thus, IL-6 failed to provide unique functions in the development of IgA-secreting B cells and in the establishment of Th1-associated protective immunity against rotavirus infection in adult mice.

Animals↗

[An experimental study of human tracheal epithelial transfer of human neutrophil defensin gene].

This study was amied at the possibility of production of the human neutrophil defensin in human tracheal epithelial cells when transfected with it's gene by using liposome. The plasmid vector carrying the human neutrophil defensin HNP1 (human Neutrophil Peptide-1) gene was used to transfect the human tracheal epithelial cells cultured in serum-free complement medium by lipofection reagent. Antiserum of HNP1 was prepared and used for the immunocytochemistry staining to detect expression of HNP1 gene in human tracheal epithelial cells. The result showed that recombinant eukaryote expression plasmid-pBabe-Neo-HNP1 could be transducted into human tracheal epithelial cells by liposomal transfection method. Transducted cells showed strong positive staining for HNP by immunohistochemistry assay. It was suggested that HNP1 gene could be productively transduced into human tracheal epithelial cells and expressed by using liposome. Antibiotic peptide gene might be used for gene therapy of respiratory infections.

Cells, Cultured↗

[The neutralizing effect of histidine-rich-polypeptides on LPS from suspected periodontal pathogens].

OBJECTIVE: Human parotid histidine-rich-polypeptides (HRPs) are a family of lowmolecular-weight, cationic polypeptides. HRP-1, HRP-3 and HRP-5 comprise 85%-90% of the total HRPs and are called major HRPs. There were many researches indicating the antimicrobial activities of HRPs. Recently, HRPs were reported to have an inhibitory action on the lipopolysaccharide (LPS) of E. coli, with HRP-5 being the most effective one among the three major HRPs. Since the LPS of oral gram-negative bacteria is thought to be one of the important etiological factors during the development of periodontal diseases, our experiment was aimed to investigate the neutralizing effect of human parotid HRP-5 on the LPS of anaerobic suspected periodontal pathogens, which have different chemical structures and biological activities compared with LPS of aerobic E. coli. METHODS: By using of preparative acid urea polyacrylamide gel electrophoresis (AU-PAGE), HRP-5 was purified from parotid saliva collected from healthy adults. Two stains of suspected periodontal pathogens, Porphyromonas gingivalis (P.g, 47-A) and Fusobacterium nuceatum (F. n, separated from subgingival plaque of a patient with adult periodontitis) were mass cultured. After harvested in the midlogarithmic phase, they were washed and lyophilized. The LPS of dried bacteria were extracted by the modified Westphal hot phenol-water procedures and purified by the enzyme digestion plus ultracentrifugation. Limulus test was applied to test the neutralizing effect of HRP-5 on the LPS-induced gelation of Limulus amoebocyte lysate. In brief, the standard LPS of E. coli, or extracted LPS of P. g or F. n, was preincubated with HRP-5 in a tube separately in room temperature for 10 minutes. Then the reagent of Limulus amoebocyte lysate was added in all the tubes, continued the incubation in 37 degrees C for one hour. After that, the gelation level of every tube was observed. RESULTS: LPS extracted from P. g and F. n both showed good purity and strong activities to induce gelation of Limulus amoebocyte lysate. The gelation induced by LPS (1 ng/ml) of these two anaerobic suspected periodontal pathogens were weakly inhibited by HRP-5 (10 micrograms/ml), similar to that observed with standard LPS of E. coli. To get a complete neutralizing effect on LPS, it may be important to increase the concentration of HRP-5. CONCLUSION: It appeared that HRPs could neutralize the endotoxic properties of LPS of suspected periodontal pathogens, therefore may contribute to periodontal health. The present investigation further confirmed that HRPs are important components of the host non-immune defense system.

Escherichia coli↗

[Production and some properties of a thermophilic protease from Bacillus stearothermophilus WF146].

The factors affecting Bacillus stearothermophilus WF146 for thermophilic protease producing have been investigated, more than 600 units of enzyme in 1 mL of fermented culture could be achieved under suitable condition. The protease had a molecular weight around 34 kD estimated by SDS-PAGE, and functioned optimally at pH 8.0 and 80 degrees C, respectively. In addition, the enzyme exhibited high temperature tolerance and was stable at a wide range of pH, and Ca2+ played a key role for the stability of the enzyme. While the protease activity of the enzyme was strongly inhibited by PMSF, DFP and IAA, and was not affected by DTT.

Endopeptidases↗

[Studies on spectral interferences and correction in simultaneous determination of multi-elements in sediments with ICP-AES].

Spectral interferences in the simultaneous determination of multi-elements in sediments and soil by ICP-AES were investigated and the multicomponent spectral fitting (MSF) method was used for the correction. Several factors affecting the MSF method such as the signal integration time and the spectra shift were studied. The comparison between MSF and off-peak background correction were made by analyzing national standard reference material: sediment GBW07306. The detection limit and the precision could be improved by a factor of 1.3-9.0 and 1.1-4.9 respectively and the results agreed better with those of the certified values when using MSF correction.

Aluminum↗