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Biomedical subjects

J Jia

Publications and source records attributed to J Jia.

At least 55 records · Page 3Linked to original sources
PubMed1998

Evaluation of a safety educational programme for the prevention of pesticide poisoning.

The causal factors of pesticide poisoning in spraymen usually include sloppy handling, leakage of sprayers and a lack of personal protection, as well as of a knowledge about pesticide toxicity. This paper outlines the results of a safety educational programme to prevent pesticide poisoning among Chinese village spraymen in 1991 and 1992. The programme consisted of two parts: an interview of 3,286 trained subjects who were surveyed before and after the education courses, and a survey on the prevalence of pesticide poisoning among spraymen in 10 villages in 1991 and 1992, respectively. The results showed a general improvement in the knowledge about pesticide toxicity and safe use among the surveyed subjects. The prevalence of pesticide poisoning among the surveyed spraymen decreased from 1.05% in 1991 to 0.25% in 1992. Moreover, a 68.2% reduction of pesticide poisoning cases was observed in 10 villages in 1992. The success of the safety educational programme proved that education is an effective measure for preventing pesticide poisoning.

Adult↗
PubMed1998

Research on nucleolar organizer regions of hippocampal neuron in Alzheimer's disease.

OBJECTIVE: To understand the cellular genetic expression of the cell's population by studying the nucleolar organizer regions (NORs) of hippocampal neuron of Alzheimer's disease (AD). METHODS: The postmortem human hippocampal tissues were divided into three groups, namely, the young, the elderly and the AD groups. Each group contained tissues from 10 patients. The study was conducted using image pattern analysis of the nucleoli-nucleoplasms ratio of the neurons of Nissl's stained pathological cerebral hippocampal tissues, the area of stain, and the integrating absorption of nucleoli of silver-stained NORs. RESULTS: The nucleoli-nucleoplasms ratio of the neurons of Nissl's stained cerebral hippocampal tissues, the area of stain, and the integrating absorption of the nucleoli of hippocampal neuron were decreased in the elderly and the AD groups as compared with the young group. However, the area of stain and the integrating absorption of the nucleoli of the hippocampal neurons were relatively increased in the AD group in comparison with the elderly group. CONCLUSION: Nissl's stain demonstrates the hypofunction of the hippocampal neurons in the elderly and the AD patients. The Silver stain of NORs shows the decline of rDNA transcription activity of the nucleoli of the hippocampal neurons in the elderly and the AD patients. However, the transcription activity of the nucleoli of the hippocampal neurons of AD patients was relatively improved, and the cellular genetic expression of the cell's population was relatively strengthened. These cellular morphological changes have probably reflected the cellular defensive system.

Adult↗
PubMed1998

Pathologic changes, mechanisms and diagnosis in renal bone disease.

OBJECTIVE: To investigate the incidence rate, pathologic changes, mechanisms and diagnostic methods in renal bone disease. METHODS: The blood levels of carboxyterminal parpthyriod hormone (C-PTH), 1,25(OH)2D3, calcium and phosphate, aluminum in serum and bone tissue were measured. The bone biopsy and bone scan with 99m technetium methylene diphosphonate (99mTC-MDP) were performed in 51 uremic patients. RESULTS: One hundred per cent of the patients had varying degree of pathologic changes in bone, in which 50.9% of the patients presented high-turnover bone disease, 7.8% of the patients presented low-turnover bone disease and 41.8% of the patients had mixed-type bone disease. The levels of serum C-PTH were predominently high in high-turnover bone disease while the levels of serum 1,25(OH)2D3 were significantly decreased in low-turnover bone disease. There was a high positive rate for the diagnosis of renal bone disease by bone scan with 99mTC-MDP. CONCLUSIONS: The examination of bone pathology is the most valuable method for the diagnosis of renal bone disease. Bone scan with 99mTC-MDP has reference value when clinical conditions do not allow to make bone biopsy.

Adult↗
PubMed1998

[CD44v and nm23-H1 gene product expression and its clinical significance in human recurrent bladder cancer].

OBJECTIVE: To investigate the expression of the CD44v and nm23-H1 gene products and its clinical significance in human recurrent bladder cancer. METHOD: The CD44v and nm23-H1 gene products in 45 cases of bladder cancer were analysed quantitatively by flow cytometry and cytoimmunofluorescence staining. RESULT: The CD44v gene product overexpression and nm23-H1 gene product low expression were correlated with invasive extent and recurrence of bladder cancer (P < 0.05). The correlation coefficients between CD44v gene product and nm23-H1 gene product were gamma = -0.2876 in bladder cancer. The correlation coefficients between CD44v gene product and nm23-H1 gene product were gamma = -0.4238 in recurrent bladder cancer. CONCLUSION: The expression of CD44v and nm23-H1 gene product cooperated in growth and progress of bladder cancer. Both CD44v and nm23-H1 gene products were an objective indication of invasive extent and recurrence of bladder cancer.

Adult↗
PubMed1998

[The polymorphic study of HLA-DRB1 gene in Chinese Liaoning Han with PCR-sequence specific primers].

8 allele and group specificity at HLA-DRB1 locus were genotyped in 159 unrelated individuals of Liaoning Han, with polymerase chain reaction-sequence specific primers. The range of gene frequencies was from 0.02201-0.23899. Heterozagosity was 83%. 33 out of 36 theoretical genotypes were identified and the result conformed to Hardy-Weinberg equilibrium law. The present method can be used not only in paternity test, individual identification, but also in clinic graft matching between donor and recipient as well as the study of HLA.

Alleles↗
PubMed1997

Crystal structure of nitrile hydratase reveals a novel iron centre in a novel fold.

BACKGROUND: Nitrile hydratases are unusual metalloenzymes that catalyze the hydration of nitriles to their corresponding amides. They are used as biocatalysts in acrylamide production, one of the few commercial scale bioprocesses, as well as in environmental remediation for the removal of nitriles from waste streams. Nitrile hydratases are composed of two subunits, alpha and beta, and they contain one iron atom per alphabeta unit. We have determined the crystal structure of photoactivated iron-containing nitrile hydratase from Rhodococcus sp. R312 to 2.65 A resolution as a first step in the elucidation of its catalytic mechanism. RESULTS: The alpha subunit consists of a long N-terminal arm and a C-terminal domain that forms a novel fold. This fold can be described as a four layered structure, alpha-beta-beta-alpha, with unusual connectivities between the beta strands. The beta subunit also contains a long N-terminal extension, a helical domain, and a C-terminal domain that folds into a beta roll. The two subunits form a tight heterodimer that is the functional unit of the enzyme. The active site is located in a cavity at the subunit-subunit interface. The iron centre is formed by residues from the alpha subunit only-three cysteine thiolates and two mainchain amide nitrogen atoms are ligands. CONCLUSIONS: Nitrile hydratases contain a novel iron centre with a structure not previously observed in proteins; it resembles a hybrid of the iron centres of heme and Fe-S proteins. The low-spin electronic configuration presumably results in part from two Fe-amide nitrogen bonds. The structure is consistent with the metal ion having a role as a Lewis acid in the catalytic reaction.

Binding Sites↗
PubMed1997

Crystal structure of the reduced Schiff-base intermediate complex of transaldolase B from Escherichia coli: mechanistic implications for class I aldolases.

Transaldolase catalyzes transfer of a dihydroxyacetone moiety from a ketose donor to an aldose acceptor. During catalysis, a Schiff-base intermediate between dihydroxyacetone and the epsilon-amino group of a lysine residue at the active site of the enzyme is formed. This Schiff-base intermediate has been trapped by reduction with potassium borohydride, and the crystal structure of this complex has been determined at 2.2 A resolution. The overall structures of the complex and the native enzyme are very similar; formation of the intermediate induces no large conformational changes. The dihydroxyacetone moiety is covalently linked to the side chain of Lys 132 at the active site of the enzyme. The Cl hydroxyl group of the dihydroxyacetone moiety forms hydrogen bonds to the side chains of residues Asn 154 and Ser 176. The C3 hydroxyl group interacts with the side chain of Asp 17 and Asn 35. Based on the crystal structure of this complex a reaction mechanism for transaldolase is proposed.

Catalysis↗
PubMed1997

The pathogenesis of non-freezing cold nerve injury. Observations in the rat.

Non-freezing cold nerve injury is uncommon in civilian practice, but may reach epidemic proportions in war zones. Studied since the time of Hippocrates, its aetiology has remained elusive. We sought to replicate experimentally, a peripheral nerve cold temperature gradient, since this has been emphasized in clinical descriptions. Our observations, in the rat, of the vasa nervorum show that cold-induced intravascular aggregation is followed by a 'no-reflow' phenomenon which culminates in endothelial damage and delayed thrombotic occlusion.

Animals↗
PubMed1997

[The study of women's bone density in Beijing].

Bone mass of 434 healthy women aged from 20-65 years was measured at both distal and mid-radius of the non-dominant arm by using a single-photon absorptiometer (SPA) with an 241Am source (model SD-1000), and bone density and related factors were studied. The bone density in women reached the peak value around 40 years old and the bone loss began around 45 years old. Bone loss was accelerated after menopause, with faster speed in trabecular bone than in cortical bone. The effect of menopause on bone loss was more significant than the effect of advancing age. Among 174 menopausal women, 9.8% had fractures. The bone density of postmenopausal women with history of bone fracture was lower than that of those without fracture. The results of this study suggest that the measurement of bone density can be used to predict the risk of osteoporotic fractures.

Absorptiometry, Photon↗
PubMed1996

Crystal structure of transaldolase B from Escherichia coli suggests a circular permutation of the alpha/beta barrel within the class I aldolase family.

BACKGROUND: Transaldolase is one of the enzymes in the non-oxidative branch of the pentose phosphate pathway. It transfers a C3 ketol fragment from a ketose donor to an aldose acceptor. Transaldolase, together with transketolase, creates a reversible link between the pentose phosphate pathway and glycolysis. The enzyme is of considerable interest as a catalyst in stereospecific organic synthesis and the aim of this work was to reveal the molecular architecture of transaldolase and provide insights into the structural basis of the enzymatic mechanism. RESULTS: The three-dimensional (3D) structure of recombinant transaldolase B from E. coli was determined at 1.87 A resolution. The enzyme subunit consists of a single eight-stranded alpha/beta-barrel domain. Two subunits form a dimer related by a twofold symmetry axis. The active-site residue Lys132 which forms a Schiff base with the substrate is located at the bottom of the active-site cleft. CONCLUSIONS: The 3D structure of transaldolase is similar to structures of other enzymes in the class I aldolase family. Comparison of these structures suggests that a circular permutation of the protein sequence might have occurred in transaldolase, which nevertheless results in a similar 3D structure. This observation provides evidence for a naturally occurring circular permutation in an alpha/beta-barrel protein. It appears that such genetic permutations occur more frequently during evolution than was previously thought.

Amino Acid Sequence↗
PubMed1996

Crystallization and preliminary X-ray crystallographic analysis of recombinant transaldolase B from Eschericha coli.

Recombinant transaldolase from Escherichia coli, an enzyme of the pentose phosphate pathway has been crystallized by the vapor-diffusion method using polyethylene glycol 6000 as precipitant. The crystals are orthorhombic, space group P2(1)2(1)2(1) with cell dimensions a = 68.9, b = 91.3 and c = 130.5 A and diffract to 2 A resolution on a conventional X-ray source. The asymmetric unit very likely contains two subunits, corresponding to a packing density of 2.9 A(3) Da(-1).

Journal Article↗
PubMed1996

Characterization of a monoclonal antibody specific for H type 2 structure of ABO blood group, and its use for measuring H type 2 on human red blood cells.

A monoclonal antibody 3A5 specific for the human red blood cells was produced by immunizing BALB/c mouse with human erythrocyte membranes of group O following the immunization protocol of selectively killing the antigen-stimulated lymphocytes. The monoclonal antibody 3A5 we obtained agglutinated red blood cells regardless of individuals of blood group A, B, or O types, but not those from a person with a rare para-Bombay type which is the H-deficient phenotype. The hemagglutination reaction of 3A5 was not inhibited by saliva from either secretor or nonsecretor individuals. The specificity of 3A5 was studied by adsorption with and elution from synthetic oligosaccharide immunoadsorbents including H disaccharide, and H type 1, 2, 3, and 4 structures. Also, the reactivity of 3A5 with synthetic oligosaccharide-BSA complexes for H type 1, H type 2, Le(a), Le(b), A, and B was determined by an immunoassay. We found that 3A5 did not react with any of these synthetic oligosaccharides except H type 2. From these results, the antigenic epitope recognized by 3A5 was demonstrated to be the H type 2 structure. Additionally, the H type 2 substance on erythrocytes was quantitatively analyzed using 3A5.

ABO Blood-Group System↗
PubMed1996

[Sixty years of study on history of Chinese legal medicine].

The paper introduces all aspects of history of Chinese legal medicine, including brief history of legal medicine, comments on ancient methods of inspection, bibliography, books on criminalislics, figures, special subjects, division of historical periods, re-printed ancient works and its foreign versions, and international academic exchanges.

China↗
PubMed1995

Mechanism of an ATP-dependent carboxylase, dethiobiotin synthetase, based on crystallographic studies of complexes with substrates and a reaction intermediate.

The crystal structures of six complexes of homodimeric Escherichia coli dethiobiotin synthetase with a variety of substrates, substrate analogs, and products have been determined to high resolution. These include (1) the binary complex of dethiobiotin synthetase and the N7-carbamate of 7,8-diaminononanoic acid, (2) the binary complex of enzyme and the alternate substrate, 3-(1-aminoethyl)-nonanedioic acid, (3) the binary complex of enzyme with the product ADP, (4) the quaternary complex of enzyme, ADP, the N7-carbamate of 7,8-diaminononanoic acid, and Ca2+, (5) the ternary complex of enzyme, the ATP analog adenylyl (beta, gamma-methylene)diphosphonate, and the N7-carbamate of 7,8-diaminononanoic acid, and (6) the quaternary complex of enzyme, the ATP analog adenylyl (beta, gamma-methylene)diphosphonate, 7,8-diaminononanoic acid, and Mn2+. One molecule of each substrate binds to one monomer of the enzyme. ADP and the ATP analogue bind to the classical mononucleotide binding fold with the phosphate groups close to the phosphate binding loop Gly8--Thr16 between beta-strand beta 1 and the N-terminus of alpha-helix alpha 1. The adenine ring is bound in a pocket between beta-strands beta 6 and beta 7. In the quaternary complex with Mn2+, the metal binding site is found in the vicinity of the beta- and gamma-phosphate groups. Two oxygen atoms from the phosphates and oxygen atoms from the side chains of Asp54, Thr16, and Glu115 are ligands to the Mn2+ ion in the quaternary complex. In the complex with ADP and the N7-carbamate of 7,8-diaminononanoic acid prepared in the presence of Ca2+ ions, a different metal binding site is found. The Ca2+ ion is coordinated to an oxygen atom of the alpha-phosphate group of the nucleotide, the side chain of Asp54, and solvent molecules. The 7,8-diaminononanoic acid substrate molecule interacts with residues from both subunits, making the dimer the minimal functional unit. The diamino group binds between the loops after beta 2 and beta 4, and the terminal carboxyl group at the hydrophobic tail of the substrate interacts with the amino terminus of helix alpha 5 and with the side chain of Tyr187 in helix alpha 6 of the second subunit at the monomer-monomer interface. Strong additional electron density close to the N7 nitrogen atom of the 7,8-diaminononanoic acid substrate in some complexes indicates that, even in the absence of added bicarbonate in the crystallization mixture, the carbamylated intermediate is formed in the crystal.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Diphosphate↗
PubMed1995

[The law of ancient states in Asia Minor and forensic medicine].

The relevant materials to forensic medicine in ancient law of Asia Minor countries, including Sumerian Law, Hammurabi's code, Hittite Code, Assyrian Law, and Mosaic Law, are reported comprehensively in this paper. The earliest materials can be traced back to 21 century B.C. It indicates that these materials described in ancient law in the world belongs to Asia Minor countries. The author considered that those materials are very important for tracing the source of forensic medicine, especially clinical forensic medicine and compensation medinine.

Forensic Medicine↗
PubMed1994

[Sprouting of forensic medicine].

Since there are materials relevant to medical jurisprudence in Qin Lu (law of Qin Dynasty), Feng Zhen Shi (sealed pattern of investigation) and Huangdi Neijing (inner canon of Yellow Emperor), and the examining system of Warring States Period include procedures, personnel and reports on examination of medical jurisprudence, it can be concluded that the pre-Qin Period saw the sprouting period of Chinese medical jurisprudence.

China↗