Fractionation of heavy metals in different particle-size sediments and its relationship with heavy metal pollution.
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Aluminum Silicates↗
Biomedical subjects
S Z Zhang
Publications and source records attributed to S Z Zhang.
Analytical solution for the extremums of cell water volume and cell volume using a two-parameter model.
Based on a two-parameter model [Cryobiology 37 (1998) 271-289], the analytical solution for the extremums of cell water volume and cell volume for a two-solute system are obtained. Compared with the numerical solution, the analytical solution offers an accurate but simple choice. The approximate solution [Cryobiology 40 (2000) 64-83] for the extremum of cell water volume is also discussed, the reason for the deviation is presented.
Cell Membrane Permeability↗
Further characterization and population data for the pentanucleotide STR polymorphism D10S2325.
Pentanucleotide tandem repeat markers are interesting for forensic sciences, because they may present less stutter on the electrophoretic pattern. We focused on the analysis of the DNA sequence for each allele at the pentanucleotide STR locus D10S2325 in order to understand their structures in the human genome and to construct human allelic ladder, which is necessary for forensic DNA typing. In order to evaluate the forensic applicability of D10S2325 and to construct a preliminary database, the genotype distributions and allele frequencies in three major ethnic groups were investigated. The population samples included Caucasians (Germans), Africans (African Americans), and Asians (Chinese). A total of 520 samples from unrelated individuals was analyzed by Amp-FLP. An example of each allele and new alleles were sequenced. Allele determination was carried out by comparison with a sequenced human allelic ladder made in-house. This pentanucleotide STR provided easily interpretable results. A total of 15 alleles was found in our population samples. Three new alleles were observed and named as alleles 19 and 21 based on the number of repeat motifs, while allele 19 can be divided further into two alleles, 19a and 19 according to analysis of the sequence. No evidence of deviation from Hardy-Weinberg equilibrium was observed. In 64 confirmed father/mother/child triplets no mutation event was observed. Using a maximum likelihood method, the mutation rate was indirectly estimated as 2.5 x 10(-5). These results suggest that D10S2325 is a useful marker for forensic casework and paternity analysis.
Black or African American↗
A novel deletion mutation of the EXT2 gene in a large Chinese pedigree with hereditary multiple exostosis.
Hereditary multiple exostoses (EXT) is an autosomal dominant disease characterized by the formation of cartilage-capped prominences (exostoses) that develop from the juxta-epiphyseal regions of the long bones. 3 genes are known to be involved in the formation of exostoses. Among them, EXT1 and EXT2, which encode enzymes that catalyse the biosynthesis of heparan sulfate, an important component of the extracellular matrix, are responsible for over 70% of the EXT cases. A large Chinese family with hereditary multiple exostoses has been analysed and the disease-causing mutation has been found. Blood samples were obtained from 69 family members, including 23 affected individuals. The EXT phenotype was shown to be linked to the EXT2 gene by using 2-point linkage analysis. After polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) analysis and DNA sequencing, a previously unreported deletion of a G in exon 3 of EXT2 gene was observed. This deletion co-segregated with the disease phenotype, suggesting that it is the disease-causing mutation in this family. Furthermore, in at least 4 members chondrosarcoma occurred after either an operation or injury of the exostosis and 3 of them died of the malignancy in the family. Whether the operation or injury was responsible for the malignant transformation still needs further study.
Base Sequence↗
Allele sequences of six new Y-STR loci and haplotypes in the Chinese Han population.
Human chromosome Y-specific short tandem repeat (Y-specific STR) markers have useful properties for forensic applications. However, there is a need to develop more Y-specific STR markers, because the discriminating power of each STR locus is limited. In the present study, we describe our results on six new Y-specific STR markers that were initially located using sequence database information by Ayub et al. and were named DYS434, DYS435, DYS436, DYS437, DYS438 and DYS439. Our studies focused on the analysis of the DNA sequence for each allele at all six Y-specific STR loci in order to understand their structures in the human genome and to construct human allelic ladders, which are necessary for forensic DNA typing. In addition, the haplotype distribution for all six analyzed loci was studied in a Chinese Han population sample. The results indicate that DYS434, DYS435, DYS436, DYS437, DYS438 and DYS439 are useful Y-specific STR markers for forensic sciences.
Alleles↗
Pharmacokinetics of metformin gastric-retentive tablets in healthy volunteers.
The single-dose pharmacokinetics of two gastric-retentive, extended-release tablet formulations of metformin hydrochloride in fed, healthy volunteers were compared with those of the currently marketed immediate-release metformin hydrochloride product. The plasma concentration-time profiles demonstrated extended-release characteristics from the gastric-retentive tablets. The mean bioavailability from each gastric-retentive tablet was approximately 115%, relative to the immediate-release (IR) product. Cmax values were lower and tmax values were greater for the gastric-retentive tablets compared with the IR product. In contrast to conventional extended-release metformin tablets reported in the literature, these gastric-retentive tablets showed extended-release plasma concentration profiles of metformin hydrochloride and increased bioavailability compared with the immediate-release tablet.
Adult↗
Establishment of transgenic mouse harboring hepatitis B virus (adr subtype) genomes.
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Animals↗
[Pyramiding and marker-assisted selection for powdery mildew resistance genes in common wheat].
This project used the strategy of discarding susceptible individual plants and keeping resistance ones by resistance identification in breeding populations and planted resistant plants next in earlier generations (F1-F3), and performing marker-assisted selection combining resistance identification in later generation (F4 generation) for pyramiding powdery mildew resistance. F4 populations from crosses of elite parents possessing different Pm genes were screened by using molecular markers tightly linked to Pm2, Pm4a, Pm8 and Pm21 genes, respectively. Fourteen individual plants with Pm4a and Pm21 out of 40 F4 plants were identified. Sixteen individual plants containing Pm2 and Pm4a out of 80 F4 plants and six plants possessing Pm8 + Pm21 out of 58 F2 plants were screened. Notably, the plants with Pm2 and Pm4a showed high level resistance or immunity to powdery mildew, while plants with single Pm2 or Pm4a had lower resistance. The results suggest that the strategy of pyramiding different Pm genes provide an alternative way of utilizing resistance gene resources for breeding new types of resistance lines and cultivars, which will have significance not only in breeding practice but also in theoretical research.
Breeding↗
[Distribution of MICA microsatellite in 13 population groups of China].
The genetic data of MICA microsatellite were obtained by genotyping 577 samples in 13 population groups of China, which are Han-YN, Han-GD, Han-SD, Bai, Dai, Lahu, Li, Naxi, Sala, She, Tu, Wa and Zang-YN, with genescan. Five alleles have been observed in the population groups, which are A4, A5, A5.1, A6 and A9. A5 allele is the most frequent in all population groups except Lahu and Li, while the most frequent allele for Lahu and Li is A5. 1 and A4 respectively. The second most frequent allele is the A5.1 in Han-YN, Han-SD, Dai, Naxi, Sala, She, and Wa. The lest frequent allele for Han-YN, Han-GD, Lahu, Naxi, She, Wa is the A6 which is not observed in Li. A4 allele is the lest frequent in Han-SD, Bai, Dai, Sala, Tu, Zang-YN. The results show that the distribution of MICA microsatellite is different in these population groups, and the polymorphism information contents (PIC) of this microsatellite is high. It is a potential useful marker in the study of human origin and migration, personal identification, gene mapping and location, and disease diagnosis.
China↗
Monovalent cation effects on the activity of the xenobiotic/medium-chain fatty acid:CoA ligases are substrate specific.
The effect of monovalent cation on the activity of the XL-I and XL-III forms of xenobiotic/medium-chain fatty acid:CoA ligase (XM-ligase) was investigated using a variety of different carboxylic acid substrates. With benzoate or p-hydroxybenzoate as substrate, the XL-I ligase was essentially inactive in the absence of monovalent cation. However, with phenylacetic acid and medium-chain fatty acids as substrate, the enzyme retained 3 to 10% activity upon removal of monovalent cation. Further, while Na+ was ineffective with benzoate and p-hydroxybenzoate as substrates, it was effective with other substrates, although still less effective than K+. For XL-III, activity toward benzoate, hydroxybenzoate, and salicylate was insignificant in the absence of monovalent cation, but this rate was 10% of the K(+)-supported rate for hexanoate and 20% for decanoate. Also, with decanoate as substrate, XL-III was activated more by Na+ than by K+. Thus, the nature of the dependence on monovalent cation for activity is substrate-selective. Kinetic analysis of the effect of K+ on the activity of XL-I and XL-III revealed that activation by K+ was not the result of alteration of the affinity of the enzymes for either ATP or the carboxylic acid. For both forms of XM-ligase, K+ was found to enhance the affinity of the enzyme for CoA, regardless of the substrate, although the extent of the enhancement was substrate-specific. In almost all cases there was further activation, even at saturating concentrations of CoA, which indicates an additional effect of monovalent cation on the catalytic rate constant for the reaction. The exception was activation of XL-III activity toward decanoate, which was solely the result of enhanced binding affinity for CoA.
Animals↗
The A5.1 allele of the major histocompatibility complex class I chain-related gene A is associated with psoriasis vulgaris in Chinese.
BACKGROUND: Recent studies have demonstrated an association of a polymorphic (GCT)n triplet repeat in the transmembrane (TM) region of the major histocompatibility complex (MHC) class I chain-related gene A (MICA), one of the MHC class I chain-related (MIC) family members, with some autoimmune diseases, including Behçet's disease, acute anterior uveitis, Takayasu's arteritis and others. OBJECTIVES: The aim of this study was to examine whether the MICA gene is associated with psoriasis vulgaris (PS) in Chinese. PATIENTS AND METHODS: The (GCT)n polymorphism of the MICA gene was investigated in 200 healthy Chinese of Han origin and 300 patients with PS by polymerase chain reaction amplification and denaturing polyacrylamide gel electrophoresis. RESULTS: Five alleles, namely A4, A5, A6, A9 and A5.1 were found in both groups. Comparison of the data from both groups revealed that the A5.1 allele was present at a significantly higher frequency in the patient group (41.5%) than in the control group (23.0%) (Pc < 0.0001, Pc means the probability of a comparison with the control group). The frequency of A5.1-positive cases was also significantly increased in the patient group (68.0%) as compared with the controls (38.0%) (Pc < 0.0001). Furthermore, the carrier frequency of A5.1-positive was significantly increased in psoriatic patients with a positive family history and with early onset as compared with sporadic cases (Pc = 0.0005) and with late onset PS (Pc = 0.002). CONCLUSIONS: These results suggest that the MICA gene may be associated with the development of PS in Chinese.
Adolescent↗
[Modification of L-asparaginase with colominic acid and the new characteristics of the modified enzyme].
The colominic acid was covalently coupled to L-asparaginase molecule by reductive amination. Depending on the molar ratios of colominic acid-asparaginase (30:1, 50:1 and 100:1), a modified enzyme molecule contained 4.7, 7.2 and 12 colominic acid molecule, they retained 58%, 56% and 33.2% of the initial asparaginase activity, respectively. In comparison with the native enzyme, modified enzyme had lower immunogenicity and antigenicity, longer half-life time (in vitro), more resistance ability to trypsin proteolysis, and similar Km value for L-asparagine.
Asparaginase↗
[cDNA cloning, sequence analysis of trehalose-6-phosphate synthase gene from Saccharomyces cerevisiae AS2.1416].
The trehalose-6-phosphate synthase gene tps1 was amplified from yeast S. cerevisiae AS2.1416 cDNA library by polymerase chain reaction. This 1.5 kb fragment was cloned into PstI and BamHI sites of pGEM-T easy vector and the sequence of the gene indicated the cloned tps1 gene contained 1485 nucleotides encoding for 495 amino acid and shared a sequence homology of 99.6% with that from S. cerevisiae S288C.
Cloning, Molecular↗
[Computed tomographic findings of the development of the bone around the vestibular aqueduct in Meniere's disease].
OBJECTIVE: To study the development of the bone around the vestibular aqueduct (VA) in Meniere's disease (MD) by CT. METHOD: The experiment consisted of three groups; normal ear group, non-MD vertigo group and MD group. VA in each group was examined by CT, and the minimum distance between the posterior semicircular canal and the posterior petrous surface where contain the endolymphatic sac. RESULT: VA visualization rate in MD was low, P-P distance in MD group was shorter than that of normal ear group and non-MD vertigo group. CONCLUSION: It is the fundamental pathological anatomy in MD that VA and the bone around VA are maldeveloped.
Adolescent↗
[Quantitative assay of telomerase activity in head and neck squamous cell carcinoma].
OBJECTIVE: To detect and quantify telomerase activity in tissues from head and neck squamous cell carcinoma (HNSCC), and to explore whether the levels of telomerase activity can be a useful marker for cancer risk assessment in HNSCC. METHOD: The levels of telomerase activity of 55 fresh specimens obtained from 25 patients with HNSCC were detected by the method of telomeric repeat scintillation radioactive count, including 25 primary tumors, 7 samples of neck metastases and 23 corresponding normal tissues as control. In 7 patients, both primary and metastatic tumors were obtained. The levels of telomerase activity were determined with a liquid scintillation counter. The basic principle of the technique is that a G-rich oligonucleotide strand of telomeric sequence is used as primer, 3H-dTTPs are incorporated into the products while telomerase elongates the primers, and then free 3H-dTTPs are removed by rinsing step, finally radioactive count per minute (cpm) of products is detected, and the levels telomerase activity can be evaluated according to the value (cpm). RESULT: 1. The levels of telomerase activity (cpm) in tissues with HNSCC were significantly higher than those in the normal tissues (P < 0.05); 2. The levels of telomerase activity in the primary tumors were higher than those of their neck metastases, but the difference was not statistical significance (P > 0.05); 3. The levels of telomerase activity in the neck metastases were remarkably higher than those in the normal tissues (P < 0.05). CONCLUSION: 1. Detection of telomerase activity in HNSCCs can be a useful marker for cancer assessment. 2. To quantify telomerase activity may have clinical diagnostic value for HNSCC. 3. The levels of telomerase activity in the metastatic lymph nodes were higher.
Carcinoma, Squamous Cell↗
[The effect of CO2 laser combined with chloroquini phosphate in the treatment of oral lichen planus: report of 80 cases].
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Journal Article↗
Radon measurements in underground dwellings from two prefectures in China.
Radon, an established lung carcinogen, remains the single most important environmental radiation exposure. Yet, an excess of lung cancer from breathing radon in homes has not been consistently demonstrated in studies conducted to date. To address several major problems that have hindered previous studies of lung cancer and radon in homes, we have embarked upon a lung cancer case-control study in Gansu Province, China, where a substantial proportion of the population live in underground dwellings. In this paper, we report on results of a pilot study in which radon measurements were made for 3 days in the summer in 40 homes under normal occupancy conditions using short-term E-PERM detectors and for 6 months from February through August in 49 homes using long-term alpha-track detectors. Useable E-PERM data were obtained from 38 homes and useable alpha-track data from 47 homes. For both types of detectors, measurements were approximately log-normally distributed. Arithmetic and geometric means were 233 and 185 Bq m-3 (range 74-1,590 Bq m-3) for E-PERM measurements and 165 and 158 Bq m-3 (range 74-592 Bq m-3) for alpha-track measurements, respectively; 68% of E-PERM measured homes and 55% of alpha-track measured homes exceeded 148 Bq m-3. Alpha-track measurements made at the entry, middle, and rear areas of the underground dwellings did not differ significantly (arithmetic means of 168, 162, and 165 Bq m-3 with standard deviations 63, 73, and 48, respectively), which suggests that air circulation may be minimal. The underground dwellings measured in the pilot study had high radon levels and the underground dwellers may provide an excellent population for studying indoor radon and risk of lung cancer.
Air Pollution, Indoor↗
Modulation of integrin-laminin receptor function on mammary tumor cells by prostaglandin E2 receptor antagonism.
Our previous studies indicate that prostaglandin E2 (PGE2) receptors play a role in tumor metastasis. We asked if PGE2 receptor antagonism would affect murine mammary tumor cell attachment to immobilized laminin, a critical step in metastasis. The PGE2 receptor antagonist, LEO101, at a concentration of 20 micrograms/ml, inhibited tumor cell attachment to laminin and the laminin-peptide PA-22 by 41 and 82%, respectively. Immunoprecipitation studies identified the beta 1 integrin subunit as well as the alpha 3 subunit as major membrane components of these cells, whereas little or no alpha 1, alpha 5 or alpha 6 was detected. Antibody blocking studies confirmed that these cells use beta 1, but not the alpha 6 subunit, to attach to laminin. Immunoprecipitation studies of untreated or LEO101-treated cells indicate that the expression of the alpha 3 integrin, but not other integrins, was decreased by LEO101.
Amino Acid Sequence↗