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Biomedical subjects

C Jin

Publications and source records attributed to C Jin.

At least 91 records · Page 5Linked to original sources
PubMed1999

Expression and localization of histamine H2 receptor messenger RNA in human nasal mucosa.

BACKGROUND: Histamine is an important chemical mediator in allergic rhinitis. Histamine H2 receptor (H2R) stimulation controls histamine release and mediates mucus secretion, suggesting that H2R might play some role in allergic rhinitis. OBJECTIVE: The objective of this study was to examine whether H2R mRNA expression is increased in patients with allergic rhinitis compared with normal subjects and to determine the localization of H2R mRNA in the human nasal mucosa. METHODS: We extracted RNA from scrapings of the inferior turbinate mucosa of 11 patients with allergic rhinitis. H2R and beta-actin mRNA were amplified by RT-PCR. In situ hybridization with a digoxigenin-labeled H2R cRNA probe was performed on surgical specimens of nasal turbinate of patients with allergic rhinitis. RESULTS: The mean +/- SD of H2R/beta-actin ratios were 0.12 +/- 0.16 for the scrapings of normal subjects and 0.35 +/- 0.20 for the scrapings of patients with allergic rhinitis; the difference was statistically significant (P <.01). H2R mRNA was localized in the epithelium, serous cells, and mucous cells. CONCLUSION: These data suggest that H2R mRNA is localized in the epithelium and the submucosal glands and that increased H2R may be playing some role in patients with allergic rhinitis.

Actins↗
PubMed1999

Fluorescent in situ hybridisation (FISH) characterisation of pericentromeric breakpoints on chromosome 5 in head and neck squamous cell carcinomas.

Pericentromeric rearrangements, such as isochromosomes and whole-arm translocations, are frequently encountered in short-term cultures from head and neck squamous cell carcinomas (HNSCC). To characterise further the localisation of the breakpoints in such rearrangements, metaphase cells from seven HNSCC known to carry structural rearrangements of the pericentromeric region of chromosome 5 were investigated using fluorescent in situ hybridisation (FISH) techniques. With a whole chromosome painting probe it could be confirmed that all chromosome 5 rearrangements identified at cytogenetic analysis contained chromosome 5 material. By using a centromere-specific alpha satellite probe it could be shown, however, that cytogenetically identical derivative chromosomes had different breakpoints. Thus, we conclude that the results of the present investigation add further support to the hypothesis that the essential outcome of near-centromeric chromosome rearrangements is the creation of genomic imbalances, i.e. gain and/or loss of neoplasia-associated genes.

Aged↗
PubMed1999

Molecular cloning and expression of Galbeta1,3GalNAc alpha2, 3-sialyltransferase from human fetal liver.

Based on the sequences of the highly conserved segments in the previously cloned sialyltransferases, a cDNA encoding Galbeta1, 3GalNAc alpha2,3-sialyltransferase (SIATFL) has been isolated from human fetal liver. Expression analysis of the gene has been performed with various carcinoma cell lines, fetal tissues, fetal and adult liver and both hepatoma and the surrounding tissue from the same liver. The SIATFL gene was expressed poorly in fetal liver and in adult liver, slightly in hepatoma and highly in the surrounding tissue of hepatoma. The cDNA encoding the putative active domain was expressed in COS-1, Escherichia coli, and Pichia pastoris. The recombinant protein expressed in COS-1 could catalyse the transfer of NeuAc from CMP-NeuAc to asialo-fetuin. No enzyme activity was detected with a 32-kDa protein in E. coli and both 32-kDa and 41-kDa proteins in P. pastoris. These results suggested that correct glycosylation of the enzyme might play a key role in its folding that may be directly related to the enzymatic activity.

Amino Acid Sequence↗
PubMed1999

Human localisation of band-pass filtered noise.

In this work we study the influence and relationship of five different acoustical cues to the human sound localisation process. These cues are: interaural time delay, interaural level difference, interaural spectrum, monaural spectrum, and band-edge spectral contrast. Of particular interest was the synthesis and integration of the different cues to produce a coherent and robust percept of spatial location. The relative weighting and role of the different cues was investigated using band-pass filtered white noise with a frequency range (in kHz) of: 0.3-5, 0.3-7, 0.3-10, 0.3-14, 3-8, 4-9, and 7-14. These stimuli provided varying amounts of spectral information and physiologically detectable temporal information, thus probing the localisation process under varying sound conditions. Three subjects with normal hearing in both ears have performed five trials of 76 test positions for each of these stimuli in an anechoic room. All subjects showed systematic mislocalisation on most of these stimuli. The location to which they are mislocalised varies among subjects but in a systematic manner related to the five different acoustical cues. These cues have been correlated with the subject's localisation responses on an individual basis with the results suggesting that the internal weighting of the spectral cues may vary with the sound condition.

Acoustic Stimulation↗
PubMed1999

[Susceptibility gene location of simple congenital heart defect by transmission disequilibrium test].

OBJECTIVE: To locate the susceptibility gene of human simple congenital heart defect(CHD) and provide a sound basis for further gene cloning. METHODS: Three short tandem repeats(STRs) in regions of chromosome 7p14-15, 17q21 where exist Hox gene family's A, B clusters which regulate the embryonic heart development were chosen. Genotypes of 112 members in 39 CHD families were analyzed by amplifying the STR fragments using fluorescence-PCR technique. Then transmission disequilibrium test(TDT) was used to test the data of genotypes. RESULTS: Statistical chi(2) values of D7S1808, D7S673 and D17S791 were 31.3(P<0.005), 11.12(P<0.05) and 6.65 (P>0.05) respectively. These suggest that the former two are associated with CHD, while the latter is not. CONCLUSION: Human simple CHD is associated with Hox gene A cluster. Hox A gene may be a candidate CHD's susceptive genes. The location of the CHD's susceptive genes is in chromosome 7p14-15.

Chromosomes, Human, Pair 7↗
PubMed1999

[Rapid detection of trisomy 21 by quantitative polymerase chain reaction].

OBJECTIVE: Studying gene diagnosis of trisomy 21 by means of quantitative polymerase chain reaction(PCR). METHODS: Polymorphic short tandem repeat(STR) at D21S11 served as the gene marker, and a pair of primers was synthesized. The samples from 11 normal subjects and 28 cases of trisomy 21 were analyzed by quantitative PCR. RESULTS: 10 normal subjects showed two bands with a ratio of 1:1, and a subject showed one band. Of 28 cases of trisomy 21, 24 cases showed two bands with a ratio of 2:1, 3 cases showed three bands with a ratio of 1:1:1, and 1 case showed one band. CONCLUSION: Polymorphic STR at D21S11 is a valuable gene marker for diagnosis of trisomy 21. Trisomy 21 can be diagnosed rapidly and accurately within 24 hours by quantitative PCR.

Down Syndrome↗
PubMed1999

Purification and properties of genetic expressing product of thermostable protease from Bacillus stearothermophilus HY-69.

The thermostable metal protease gene from Bacillus stearothermophilus HY-69 had been cloned and expressed in Bacillus subtilis MI113. The genetic expressing product of the enzyme was purified by CM-cellulose chromatography. The product shows homogeneity on PAGE. Its molecular weight is 27,000 +/- 1000 by SDS-PAGE and Sephadex G100 filtration, respectively. The alpha-helix content of the protease is estimated to be about 66%, the beta-turn about 28%, the random coil about 6%, but not beta-sheet, calculated from the circular dichroism data. The optimal temperature of the enzyme was 70 degrees C. When the enzyme was denatured in 3 mol/L of Gdn--HCl in phosphate buffer pH6.0 for 20 min, it remained about 40% of original activity. It shows that it is rather resistant to heat and Gdn-HCl denaturation. Its conformational variety coursed by Gdn-HCl was investigated by the far UV circular dichroism and fluorescence spectra. The results show that the enzyme has more compact conformation and internal hydrophobility.

Amino Acids↗
PubMed1999

Cloning and sequencing of sialyltransferase gene from human fetal liver.

Based on sequences of the highly conserved segments in the previously cloned sialyltransferases, 150 bp fragments were amplified and sequenced using human fetal liver mRNA as template. One of them (s38) showed 57%-97% identities with the active domains of previously cloned sialyltransferases. Based on the sequence of s38, an oligonucleotide was synthesized and labeled to screen human fetal liver cDNA library. A cDNA encoding alpha 2, 3-sialyltransferase has been isolated. The cDNA sequence included an open reading frame coding for 340 amino acid residues, and the deduced amino acid sequence showed 100% identity with that of human submaxillary gland Gal beta 1, 3GalNAc alpha 2, 3-sialyltransferase, 83.2% identity with that of pig submaxillary gland alpha 2, 3-sialyltransferase. These results suggested that the protein encoded by the cDNA from human fetal liver cDNA library was a Gal beta 1, 3GalNAc alpha 2, 3-sialyltransferase.

Base Sequence↗
PubMed1999

[Partial gene clone and nif gene homologous sequence analysis of Streptococcus sanguis].

OBJECTIVE: To analyze the sequence of Streptococcus sanguis chromosome which contains one DNA fragment of 800 base pairs (bp) and discuss Streptococcus sanguis biological features of heredity. METHODS: Streptococcus DNA of 800-bp genetic fragment was cloned and analyzed by using eukaryotic expression vector. RESULTS: By Genbank database, it showed that the 800-bp genetic sequence was highly homologous with other bacterial nifS and nifU gene, and the highest homologous score was 114. CONCLUSION: This nif gene of ATCC 10556 strain may correlate with nutrient metabolism and peroxide hydrogen release of Streptococcus sanguis.

Cloning, Molecular↗
PubMed1999

The killing effect of photodynamic therapy using benzoporphyrin derivative on retinoblastoma cell line in vitro.

OBJECTIVE: To evaluate the killing effect of photodynamic therapy (PDT) using new photosensitizer benzoporphyrin derivative complexed with human low density lipoprotein on retinoblastoma (RB) cell line in vitro. METHODS: The experiment of photodynamic killing effect on RB cell line in vitro was performed by using benzoporphyrin derivative (BPD or Verteporfin) and monochromatic light at the wavelength around 690 nm. Seven BPD concentrations (2,500 ng/ml, 1,250 ng/ml, 625 ng/ml, 312.5 ng/ml, 156.25 ng/ml, 78.125 ng/ml, 39.0625 ng/ml) and three energy densities (1.2 J/cm2, 2.4 J/cm2 and 3.6 J/cm2) were applied. The damage of the tumor cells was evaluated by MTT assay 24 hours after PDT. The changes of the ultrastructure of RB cells were observed under eleceronic microscope 4 hours after PDT. RESULTS: There was a significant dose-response relationship between tumor cell damage and BPD concentration in the medium under light irradiation at the energy density of 1.2 J/cm2. At each BPD concentration, the inhibition rate increased with the rise of energy density. RB tumor cell necrosis was found widely under electronic microscope. CONCLUSIONS: This study suggested that RB cells are very sensitive to the PDT induced by BPD in vitro. RB tumor cell were directly killed by photodynamic effect induced by BPD.

Cytotoxicity, Immunologic↗
PubMed1999

A study on the compliance of the patients with ocular fundus diseases.

PURPOSE: To investigate the compliance of the patients with ocular fundus diseases with recommendation for follow-up examination after laser treatment, and the underlying reasons for non-compliance. METHODS: 53 patients with ocular fundus disease were asked to fill in a questionnaire which includes the socio-demographic characteristics, fear of the fundus disease, conception of the laser treatment and the motivation for staying healthy. Variables were compared for the compliers group and the non-compliers group by chi-square test. RESULT: Of the 53 subjects, 35 were classified as non-compliers and 18 were classified as compliers. There was no statistically significant difference between the two groups on all selected socio-demographic factors, conception of the laser treatment and the motivation for staying healthy. Significant difference was found between the two groups on two of those items concerning the fear of the diseases (P < 0.05). About half of the participants showed the lack of knowledge about the laser treatment. CONCLUSION: The present study revealed the poor compliance of the patients with fundus disease. Patient's health beliefs influenced their compliance status.

Adult↗
PubMed1999

[Observation of autoionization levels in uranium I].

A number of Rydberg and autoionization levels of U I have been studied using three-step resonant ionization methods with three pulsed tunable dye lasers. Energy levels of uranium atom have been measured, which were located in the 49898-50880 cm(-1) energy interval.

English Abstract↗
PubMed1998

Cytogenetic and fluorescence in situ hybridization characterization of chromosome 1 rearrangements in head and neck carcinomas delineate a target region for deletions within 1p11-1p13.

Cytogenetic analyses have revealed structural rearrangements of chromosome 1 in a large fraction of head and neck carcinomas (HNCA). These aberrations frequently affect chromosomal band 1p13 and the centromeric region, the latter often in the form of isochromosome i(1q) and whole-arm translocations. To delineate the critical region involved in rearrangements of proximal 1p, we have undertaken a more precise breakpoint mapping in 13 HNCAs, using metaphase fluorescence in situ hybridization with 11 yeast artificial chromosome (YAC) clones spanning 1p. All of the tumors had chromosome 1 changes at G-banding analyses. Fluorescence in situ hybridization showed that in almost all of the cases, at least one copy of chromosome 1 was affected by centromeric rearrangement. By the use of YAC clones mapped to juxtacentromeric regions and a centromere-specific alpha-satellite probe, we detected variable breakpoints in the whole-arm translocations. At the cytogenetic level, 1p13 rearrangements were frequent. However, molecular breakpoints within this band varied among the HNCAs tested. The lack of consistently rearranged chromosome segments indicates that the pathogenetically important consequence of 1p rearrangements in HNCAs is loss and/or gain of genes outside the breakpoint regions. In an assessment of the genomic imbalances, partial or complete overrepresentation of 1q was seen in eight cases. Loss of 1p material was also identified in eight cases; and in four of them, the deleted segments were too small to be discovered by G-banding analysis. The minimal overlapping deleted region was in the interval between YAC 959C4 (band p11-p12) and the centromere (p10). Our findings indicate that a target region potentially harboring tumor suppressor gene(s) crucial for HNCA is located within chromosomal bands 1p11-p13.

Centromere↗
PubMed1998

[Identification of adhalin gene mutation in limb-girdle muscular dystrophy in Chinese].

OBJECTIVE: Limb-girdle muscular dystrophy (LGMD) is a group of severe genetic heterogeneity muscular diseases characterized by proximal muscular weakness of the pelvis and shoulder, affecting both male and female. This group of diseases involves four gene loci (13q12, 17q21,4q12,5q33). Up till now there is no research report about LGMD in Chinese. This study was intended to identify the pathogenic genes of LGMD in Chinese by mutation detecting. METHODS: The exons 2 and 3 of adhalin gene were analyzed in 13 Chinese LGMD patients and 20 controls by using PCR-SSCP and DNA sequencing. RESULTS: The R77C (Arg77Cys) missense mutation was found at the two alleles of a 9-year-old LGMD girl, which had not been found in the 40 wild type chromosomes. This is the first report on adhalin mutation that exists in LGMD in Chinese. CONCLUSION: Our results suggest that adhalin gene is one of the predisposing genes in LGMD in Chinese.

Child↗
PubMed1998

Structural changes in the region directly adjacent to the DNA-binding helix highlight a possible mechanism to explain the observed changes in the sequence-specific binding of winged helix proteins.

The hepatocyte nuclear factor 3 (HNF-3)/fork head (fkh) family contains a large number of transcription factors and folds into a winged helix motif. Despite having almost invariable amino acid sequences in their principal DNA-binding helices, HNF-3/fkh proteins show a wide diversity of sequence-specific binding. Previous studies of chimeric HNF-3/fkh proteins demonstrated that the binding specificity is primarily influenced by a region directly adjacent to the binding helix. We report our findings of an NMR structural study performed on an HNF-3/fkh family member (Genesis, formerly HFH-2) and compare it to that of another family member (HNF-3gamma) complexed to DNA and determined by X-ray crystallography. It is found that in comparison to HNF-3gamma, Genesis contains an extra small helix directly prior to the N terminus of the primary DNA contact helix. Due to the insertion of this helix, a shorter and slightly re-positioned primary DNA contact helix is observed, which we believe leads to the DNA-binding specificity differences among family members.

Binding Sites↗
PubMed1998

Structure-related inhibition of human hepatic caffeine N3-demethylation by naturally occurring flavonoids.

The effects of flavonoids on caffeine N3-demethylation, a marker activity of CYP1A2, in human liver microsomes were investigated to elucidate the inhibition mechanism and the structure-activity relationship. Caffeine N3-demethylase activity was inhibited by the presence of various flavonoids, whose structures seem to be closely related to the degree of inhibition. Among twenty-one compounds tested, the most active was chrysin with an IC50 value of 0.2 microM. Others had IC50 values ranging from 1 to more than 500 microM. Kinetic analysis revealed that the mechanism of inhibition varied among the flavonoids. The inhibitory effect was postulated to be governed by factors such as the number of hydroxyl groups and glycosylation of these free hydroxyl groups. An increase in the number of free hydroxyl groups reduced the inhibitory effect on P450 activity. Analysis of the quantitative structure-activity relationship (QSAR) showed that the volume to surface area ratio was the most effective factor on the inhibition of caffeine N3-demethylation, and the electron densities on the C3 and C4' atoms exercised significant influence on the inhibitory effect. The calculated inhibitory effect of flavonoids on CYP1A2 activity was highly correlated with the antimutagenicity of flavonoids in 2-amino-3,4-dimethylimidazo[4,5-flquinoline (MelQ)-induced umu response.

Anticarcinogenic Agents↗