Biomedical subjects

Yi Shi

Publications and source records attributed to Yi Shi.

61 records · Page 4Linked to original sources

PubMed2002

Semi-empirical relationships between effective mobility, charge, and molecular weight of pharmaceuticals by pressure-assisted capillary electrophoresis: applications in drug discovery.

Relationships between effective mobility (m(eff)), calculated charge (Z(c)), and molecular weight (MW) are semi-empirically derived for pharmaceuticals using pressure-assisted capillary electrophoresis (PACE). We determined the m(eff) at 12 different pH points (2.0-11.4) of 66 pharmaceutical-like compounds ranging in MW from 79 to 825 g/mol. Plots of the observed m(eff) values versus Z(c)/MW(x ) (where x is a fractional coefficient) gave linear relationships. For anions, it was found that the best correlation (R(2) = 0.9666) exists when the fractional coefficient is equal to 0.4920, resulting in the equation m(eff) = 0.1853 (Z(c)/MW (0.4920)). For cations, the best linear relationship (R(2) = 0.9861) gave the equation m(eff) = 0.3888 (Z(c)/MW (0.6330)). The m(eff), Z(c)/MW(x) relationships were then applied to: (i) developing a technique for selecting an appropriate pH to achieve optimal separation of pharmaceuticals and (ii) determining the maximum charge of a molecule in the pH range of determination of negative log of the dissociation constants (pK(a)) by PACE, thus enabling the correct choice of model equation to be automated without structure analysis.

Drug Evaluation, Preclinical↗

PubMed2002

Assessment of polymerase chain reaction and serology for detection of chlamydia pneumoniae in patients with acute respiratory tract infection.

OBJECTIVE: To study Chlamydia pneumoniae (C. pneumoniae) infection in 110 patients with respiratory tract infection admitted to our hospital from January to December 1995 in Nanjing. METHODS: Sputum and throat swab specimens were taken and C. pneumoniae DNA was detected by using polymerase chain reaction (PCR) with the HM-1-HR-1 primer pair. At the same time, serum samples were taken and immunoglobulin G and M (IgG and IgM) fractions of antibodies to C. pneumoniae were studied by microimmunofluorescence test. RESULTS: Prevalence of specific IgG was 70% in patients with respiratory tract infection. Seventeen patients (15.5%) were serologically diagnosed as having recent C. pneumoniae infections and 12 patients (10.9%) had positive PCR in sputum and/or swab specimens. The total positive rate was 22.7% (25/110) detected by PCR combined with serological tests. Acute infection of C. pneumoniae was common in patients with asthma (57.1%), pneumonia (35.0%), COPD (25.9%) and bronchitis (25.0%). Clinical features between C. pneumoniae infection and non-C. pneumonia infection showed no significant differences. CONCLUSIONS: Chlamydia pneumoniae is an important pathogen that causes infection of the human respiratory tract and attention should be drawn to this special illness.

Acute Disease↗

PubMed2002

Large multifunctional proteasome 2 gene Arg60His variant in autoimmune thyroid disease in Shanghai Chinese.

OBJECTIVE: To investigate the relationship between Arg60His variant in the large multifunctional proteasome 2(LMP2) gene and autoimmunune thyroid disease (AITD) in Shanghai Chinese. METHODS: By means of PCR-restriction fragment length polymorphisms(RFLP) assay, the genotypes of Arg60His variant in the LMP2 gene were determined in 367 unrelated Shanghai Chinese, including 205 patients with AITD and 162 normal control individuals. The former group was further divided into two subgroups 78 subjects with positive thyrotrophin receptor antibody(TRAb) and 127 subjects with negative TRAb but positive either thyroglobulin antibody(TGAb),thyoid microsomal antibody(TMAb) or thyroid peroxidase antibody (TPOAb). RESULTS: Significant difference ( P = 0.000)of allele frequencies of R/H 60 in the LMP2 gene was observed between Shanghai Chinese (R 0.89,H 0.11) and white Caucasians (R 0.29, H 0.71)and was also observed between TRAb positive subgroup in AITD and normal controls. The frequencies of RH genotype and H allele in TRAb positive subgroup is significantly higher than those in normal controls( P = 0.037,0.047,respectively).In AITD group, the genotype and allele frequencies of Arg60His variant in the LMP2 gene showed no significant difference between other antibody(+) subgroups and antibody(-) subgroups. CONCLUSION: Arg60His variant in the LMP2 gene may be associated with the pathogenesis of AITD in Shanghai Chinese.

Asian People↗

PubMed2002

[Effect of free-air CO2 enrichment on soil microbe in paddy field].

Utilizing FACE research site in Anzhen of Wuxi, the effect of CO2 concentration increasing on soil microbe was studied in a paddy field under the condition of local cultivation, irrigation and fertilization. The results showed that soil respiration intensity was 31.88 ml.kg-1 and bacteria number was 1.51 x 10(6) ind.g-1 dry soil in FACE area, which were greater than those in control area (soil respiration intensity 27.83 ml.kg-1, bacteria number was 1.25 x 10(6) ind.g-1 dry soil, but the differences were not significant.

Agriculture↗

PubMed2002

[Stable mechanisms of soil aggregate and effects of human activities].

Soil aggregate is the basic unit of soil structure. Its formation is a natural process but influenced severely by human activities, including land utilization, tillage disturbance, manure application, and cropping system. The improvement of soil structure is decided not only by total amount of organic C inputed into soil, but also by the composition and characteristic of organic matter. Owing to the different composition and characteristic of organic matter, there are different mechanisms for the stability of micro- and macro-aggregates.

Agriculture↗

PubMed2002

[Mechanisms of organic cementing soil aggregate formation and its theoretical models].

Soil aggregate is the basic unit of soil structure, and its formation and stabilization has direct effect on soil fertility and crop growth. For black soil with high content of organic matter, organic cementing substance is an important factor in forming soil aggregates. Based on the recent researches on organic cementing agents, this paper was focused on the nature of organic cementing substances, the effect of soil organisms and plant roots in forming soil aggregates, and the theoretical models and stable mechanisms of soil aggregate formation.

Cementation↗

PubMed2002

[Advances in the research on sources and sinks of CH4 and CH4 oxidation (uptake) in soil].

Methane (CH4) is one of the main greenhouse gases contributing greenhouse effect, and its potential greenhouse effect is 21 times of CO2. Therefore, to determine the sources and sinks of atmospheric CH4 and to assess and forecast their amounts become and important focus concerning the researches on global change and greenhouse effect. This paper summarized the researches on the sources and sinks of CH4, and amplified on the influential factors (e.g. land-use, ambient atmospheric CH4 concentration, soil temperature, soil moisture content, soil pH and soil porosity) on atmospheric and interior CH4 oxidation in soil. It is significant that studying CH4 oxidation in vertical zonation soil in forests of Changbai Mountain to evaluate the CH4 consumption in forest soil.

Biodegradation, Environmental↗