Biomedical subjects

J Jia

Publications and source records attributed to J Jia.

At least 37 records · Page 2Linked to original sources

PubMed2000

Crystallization and preliminary X-ray analysis of human grancalcin, a novel cytosolic Ca2+-binding protein present in leukocytes.

Recombinant human grancalcin, a calcium-binding protein from leukocytes, has been crystallized in the presence or absence of Ca(2+) by the vapor-diffusion method. Two crystal forms of apo grancalcin were obtained: space group P2(1), with unit-cell parameters a = 48.4, b = 81.1, c = 46.6 A, beta = 111.3 degrees, diffracting to 1.9 A, and space group C2, with unit-cell parameters a = 97.0, b = 51.9, c = 75.9 A, beta = 108.5 degrees, diffracting to 2.4 A. Crystals were also grown in the presence of 5 mM Ca(2+). They also belong to space group C2, with unit-cell parameters a = 97.4, b = 50.3, c = 77.6 A, beta = 108.2 degrees, which are very similar to the second apo grancalcin form. These crystals diffract to 2.5 A.

Apoproteins↗

PubMed2000

Triple-staining to identify apoptosis of hepatic cells in situ.

To identify apoptosis of nonparenchymal cells in fibrotic livers, we established a triple staining method which combined immunohistochemistry for cell markers and Masson staining for collagen as well as terminal deoxynucleotidyl transferase UTP nick end labeling (TUNEL). Five microm formalin fixed, paraffin-embedded liver sections were prepared for staining. Firstly, TUNEL staining was carried out to detect apoptosis of liver cells. Then, the sections were subjected to immunohistochemistry for alpha-smooth muscle actin (alpha -SMA) or KP-1 to identify hepatic stellate cells or Kupffer cells. Finally, Masson staining was performed to show the relationship between apoptosis and collagens. In addition, we optimized different conditions of fixation, digestion and color development which may affect the results.

Animals↗

PubMed2000

[Cloning of partial cDNA of rat connective tissue growth factor and expression of its mRNA in experimental liver fibrosis].

OBJECTIVE: To clone the partial cDNA sequence of rat connective tissue growth factor (CTGF) and investigate the mRNA expression of CTGF and transforming growth factor-beta 1 (TGF-beta 1) in rat experimental liver fibrosis. METHODS: A 430-base pair sequence of rat CTGF Cdna was cloned by reverse transcription-polymerase chain reaction. Sixteen female Wistar rats were allocated into bile duct occlusion group (n=8) and sham-operated group (n=8). The liver tissue mRNA levels of CTGF and TGF-beta 1 were measured by multiprobe ribonuclease protection assay (RPA). RESULTS: The cloned partial cDNA sequence of rat CTGF was 95% homology (at nucleic acid level) with the mouse counterpart. In the liver of rats with biliary fibrosis mRNA levels of TGF-beta 1 and CTGF were 4 and 7 times as high as in those of sham-operated rats, respectively. CONCLUSION: The mRNA expression of CTGF is remarkably upregulated in rat liver fibrogenesis.

Animals↗

PubMed2000

[Expression of collagen XVIII mRNA in rat liver fibrosis].

OBJECTIVE: To measure and study quantitatively the collagen XVIII mRNA in normal and fibrotic rat livers. METHODS: We used ribonuclease protection assay to investigate the collagen XVIII mRNA expression in rat liver fibrosis induced by complete bile duct occlusion (BDO). The expression level of procollagen 1 (XVIII) mRNA was compared with that of procollagen 1 (I) and tissue inhibitor of metalloproteinase 1 (TIMP1). RESULTS: mRNA levels of procollagen and TIMP 1 increased 20- and 4-fold in BDO rat livers, respectively. In contrast, hepatic procollagen 1 mRNA level increased only 1.8-fold in fibrotic rat livers. CONCLUSION: C XVIII mRNA is upregulated slightly in liver fibrosis, which is probably correlated with the fact that CXVIII is mainly expressed by hepatocytes.

Animals↗

PubMed2000

[Three-dimensional reconstruction of experimental fibrotic liver tissue and effect of herbal compound on it].

OBJECTIVE: To observe the three-dimensional structure of fibrotic liver tissue and the effect of herbal compound 861 (Cpd861) on it. METHODS: Experimental rat liver fibrosis was induced by human albumin. Liver biopsy specimens were stained with Masson trichrome staining and liver fibrosis was divided into 6 stages. Three-dimensional structure of fibrotic and Cpd861 treated liver tissue were observed by computer aided three-dimensional reconstruction with serial slices. RESULTS: The fibrous septa of fibrotic liver were continuous and wide, the sinusoids were sparsely, irregularly distributed and dilated. After treatment with Cpd861, the fibrous septa were much less than that of without treatment. The sinusoids were more regular and arranged in radius to central veins. CONCLUSION: Observed three-dimensionally, experimental rat liver fibrosis can be inhibited and reversed by herbal compound.

Animals↗

PubMed2000

The synergistic enhancement of pathology in intermittently cooled nerve.

OBJECTIVE: To explore how non-freezing cold nerve injury (NFCNI) is affected by fluctuating ambient temperatures. METHODS: The sciatic nerves of Wistar rats were exposed to either intermittent cooling and rewarming or continuous cooling. The pathology was assessed neurophysiologically and morphologically. RESULTS: More severe injury was observed when nerve was intermittently cooled, despite an identical duration and degree of cooling. CONCLUSION: The observed pathology is a result of repeated reperfusion injury to nerves that are cooled intermittently.

Animals↗

PubMed2000

Treatment of rats with experimental allergic neuritis using high dose immunoglobulin.

OBJECTIVE: To investigate the therapeutic potential of high-dose immunoglobulin (HIG) in experimental allergic neuritis (EAN) to provide a theoretical basis of its clinical use in the treatment of human inflammatory demyelinating neuropathies. METHODS: Female Lewis rats were induced to EAN, and divided into experimental and control groups. The rats were treated with either 0.3 g/kg.day-1 of IgG or an equivalent volume of 0.15 mol/L glycine. Clinical, electrophysiologic, and histologic evaluations were carried out in a blind fashion. RESULTS: Clinically, rats treated with IgG had significantly less severe symptoms (P < 0.001) and slower progression (P < 0.001) than controls. Electrophysiologically, the mean conduction latency of the experimental group was significantly shorter than controls (P < 0.05). Histologically, rats treated with IgG prepared from normal Lewis rats had a significantly lower percentage of demyelinated fibers (P = 0.01) and total abnormal fibers (P < 0.001) than controls. Statistically, clinical, electrophysiologic and morphologic data were all significantly correlated. CONCLUSIONS: The EAN animal model is reliable for observation of HIG effects, and useful to provide data for clinical work. HIG has a significant therapeutic effect in EAN when given soon after disease onset. It can reduce clinical disease severity and decrease the number of demyelinated fibers as well as the number of total abnormal fibers. For the current controversy over whether HIG is effective, the results of this research support the clinical use of HIG in human demyelinating neuropathy.

Animals↗

PubMed2000

[Reclassification of Saccharomyces strains by comparative electrophoretic karyotyping].

The strains of Saccharomyces Meyen ex Reess preserved in China General Microbiological Culture Collection Center (CGMCC) were recharacterized and reidentified according to recent taxonomic improvement of the genus. The strains AS 2.100 (originally classified in S. cerevisiae), AS 2.1158(from former USSR and originally classified in S. exiguus) and AS 2.1555(from Australia and originally classified in S. uvarum) were found to be different from the standard descriptions of the species concerned in some physiological properties. Comparative CHEF electrophoretic karyotype analysis showed that the chromosomal DNA banding pattern of AS 2.100 was similar to that of the type strain of S. bayanus, while the electrophoretic karyotypes of AS 2.1158 and AS 2.1555 were similar to those of the type and authentic strains of S. cerevisiae. Therefore, AS 2.100 was reidentified as S. bayanus, and AS 2.1158 and AS 2.1555 were reclassified in the species S. cerevisiae.

Chromosome Banding↗

PubMed1999

Cold nerve injury is enhanced by intermittent cooling.

Clinically nonfreezing cold nerve injury (NFCNI) is often preceded by fluctuating ambient temperatures. To simulate this we exposed the sciatic nerve of Wistar rats to intermittent cooling and rewarming. This paradigm was contrasted with one in which the sciatic nerve was continuously cooled. Despite an identical duration and degree of sciatic nerve cooling in both experiments, the pathology, as assessed neurophysiologically and morphologically, was much more severe when the nerve was intermittently cooled. It is likely that this exaggerated pathology is a result of repeated reperfusion injury. These experimental results suggest the need for a trial of free radical scavengers or antioxidants in models of NFCNI.

Action Potentials↗

PubMed1999

Cloning of the cbhI and cbhII genes involved in cellulose utilisation by the straw mushroom Volvariella volvacea.

The straw mushroom Volvariella volvacea is cultivated on substrates rich in cellulose and has been shown to produce a family of cellulolytic enzymes. A PCR-based strategy was adopted to clone genes involved in cellulose utilisation, using degenerate primers designed to amplify conserved catalytic domain sequences of cellobiohydrolases (CBHs). PCR with these primers produced two DNA fragments with sequence similarity to the cbhI and cbhII gene families detected in Trichoderma, Phanerochaete and Agaricus species. Full-length clones of these genes were obtained from an EMBL3 genomic library, and RACE-PCR was used to verify the presence of introns. The cbhI homologue has a coding region of 1722 bp, containing two introns, generating a 536 amino acid polypeptide product. The cbhII gene has a coding region of 1693 bp, containing five introns, and gives rise to a 470-amino acid polypeptide product. Northern and PCR analyses were used to study the expression of the genes. These revealed that transcripts of both genes were induced on medium containing cellulose with cbhI being expressed more strongly than cbhII - but were repressed on medium containing glucose.

Agaricales↗

PubMed1999

Tartrate-resistant bone acid phosphatase: large-scale production and purification of the recombinant enzyme, characterization, and crystallization.

Tartrate-resistant acid phosphatase (TRAP) is an enzyme expressed in bone-resorbing osteoclasts and certain tissue macrophages in human tissues. The functions of TRAP in biological systems are not known. Elucidation of the three-dimensional structure of the active site could yield important information about the physiological substrate(s) of the enzyme. We have produced recombinant rat bone TRAP using a baculovirus expression vector system. The production was scaled up to a 30-l bioreactor, and a method of purification in large scale was developed. The enzyme is composed of one 34 kDa polypeptide chain. Trypsin digestion resulted in a preparation where two subunits of approximately 23 kDa and approximately 16 kDa appeared after disulfide reduction. Trypsin digestion activated the enzyme. We generated monoclonal antibodies against recombinant TRAP. One of the selected antibodies detected the 23 kDa subunit in Western blotting. The reduced and oxidized forms of the enzyme could be separated by Mono-S cation-exchange chromatography. Crystals of TRAP have been obtained with ammonium sulfate/polyethylene glycol as precipitant. They belong to space group P212121 or P21212 with unit cell dimensions a = 57.2 A, b = 69.5 A, and c = 87.2 A and diffract to at least 2.2 A resolution. A packing density value of 2.55 A3/Da is consistent with one subunit in the asymmetric unit.

Acid Phosphatase↗

PubMed1999

[Immunohistochemical study of safe resection margin in the surgical treatment of laryngeal carcinoma].

OBJECTIVE: To study safe resection margin of laryngectomy according to the level of protein of gene expression. METHOD: Using citric-LSAB-immunochemical technique, the expressions of ras, c-myc and P53 were studied in different regions of larynx including 30 cases laryngeal carcinoma, border area, adjacent mucosa which was 0.5, 1.0, 1.5, 2.0 cm away from cancer and four normal laryngeal mucosa. RESULT: The results showed that both single expression and co-expression of p21, p62 and p53 increased as tissue progressed in sequence from normal mucosa, 2.0, 1.5, 1.0, 0.5 cm distant mucosa adjacent to carcinoma, border area and carcinoma. A significant different expression in most of them can be seen at regions of 0.5 cm and 1.0 cm distant from the tumor (P < 0.05). CONCLUSION: The tissue 0.5 cm adjacent to the tumor should be regarded as precancerous lesion. It is appropriate to regard 0.5 cm away from tumors as resection margins for surgical treatment of laryngeal carcinoma.

Adult↗

PubMed1999

[Effect of promoter-PTH4 on Streptomyces sporulation].

233 bp of promoter--PTH4 was subcloned into Streptomyces plasmid pIJ4083. pIJ4470 was obtained after recombinant plasmid was introduced into Streptomyces coelicolor J1501. Both Streptomyces coelicolor J1501/pIJ4083 and J1501/pIJ4470 were grown on minimal medium (MM) agar containing mannitol and 10 micrograms/mL thiostrepton for 6 days, and then ultrathin sections of colonies were prepared and stained with silver proteinate to observe glycogen biosynthesis in cell by the electron microscope. Result showed that the glycogen was produced by J1501/pIJ4083, whereas little glycogen was produced by J1501/pIJ4471. The dark color spores were not observed in J1501/pIJ4470 with lead stain in contrast with dark color spores which were produced by J1501/pIJ4083, indicating that promoter PTH4 may play an important role in physiological and morphological differentiation of Streptomyces.

Gene Expression Regulation, Bacterial↗

PubMed1998

Disruption of Escherichia coli transaldolase into catalytically active monomers: evidence against half-of-the-sites mechanism.

Disruption of the hydrogen bonding network at the interface of Escherichia coli transaldolase by substitution of R300 to a glutamic acid residue resulted in a monomeric enzyme at basic pH values, with almost no change in the kinetic parameters. The stability of the R300A and R300E mutants towards urea and thermal inactivation is similar to that of the wild-type enzyme. X-ray analysis showed that no structural changes occurred as a consequence of the side chain replacement. This indicates that the quaternary structure is not required for catalytic activity nor does it contribute significantly to the stability of the enzyme. The results are not consistent with a proposed half-of-the-sites reaction mechanism.

Amino Acid Substitution↗

PubMed1998

Crystal structure of beta-ketoacyl-acyl carrier protein synthase II from E.coli reveals the molecular architecture of condensing enzymes.

In the biosynthesis of fatty acids, the beta-ketoacyl-acyl carrier protein (ACP) synthases catalyze chain elongation by the addition of two-carbon units derived from malonyl-ACP to an acyl group bound to either ACP or CoA. The crystal structure of beta-ketoacyl synthase II from Escherichia coli has been determined with the multiple isomorphous replacement method and refined at 2.4 A resolution. The subunit consists of two mixed five-stranded beta-sheets surrounded by alpha-helices. The two sheets are packed against each other in such a way that the fold can be described as consisting of five layers, alpha-beta-alpha-beta-alpha. The enzyme is a homodimer, and the subunits are related by a crystallographic 2-fold axis. The two active sites are located near the dimer interface but are approximately 25 A apart. The proposed nucleophile in the reaction, Cys163, is located at the bottom of a mainly hydrophobic pocket which is also lined with several conserved polar residues. In spite of very low overall sequence homology, the structure of beta-ketoacyl synthase is similar to that of thiolase, an enzyme involved in the beta-oxidation pathway, indicating that both enzymes might have a common ancestor.

3-Oxoacyl-(Acyl-Carrier-Protein) Synthase↗

PubMed1998

Taurine content in Chinese food and daily intake of Chinese men.

The taurine content in Chinese food, including seafood, fresh water fish, meats and some plants, was examined in this study. Seafood was freshly collected from 4 coastal areas in China. Meat and plant food samples were obtained from food markets. The highest concentration of taurine was found in crustaceans and molluses (300-800 mg per 100 g edible portion). The amount of taurine in fish was variable. Beef, pork and lamb contained taurine in concentrations ranging from 30-160 mg per 100 g. No taurine was detected in hen eggs and plants. The daily taurine intake of representative Chinese men (18-45 years old, 60 kg body weight, light physical activity) was also studied in 1990 as a part of the Total Diet Study. Representative food samples were collected from 12 provinces in 4 areas of China. Samples were then combined and cooked according to food categories (meat, seafood, vegetables, etc) The combined meat and seafood samples were analyzed for taurine. The daily taurine intake of a standard man in the 4 areas was calculated based on the amount of food intake obtained from the dietary survey and the taurine concentration in the analyzed food samples. The result showed that the daily taurine intake of a standard Chinese man in the 4 different test areas ranged from 34 to 80 mg per day.

Adolescent↗

PubMed1998

Five novel missense mutations of the Lewis gene (FUT3) in African (Xhosa) and Caucasian populations in South Africa.

Five novel missense mutations, viz., C304 A, T370 G, G484 A, G667 A, and G808 A, in the Lewis gene (FUT3) were detected in African (Xhosa) and Caucasian individuals in South Africa. These single base substitutions may result in changes in amino acid residues from Gln102 to Lys in the 304 mutation, Ser124 to Ala in the 370 mutation, Asp162 to Asn in the 484 mutation, Gly223 to Arg in the 667 mutation, and Val270 to Met in the 808 mutation. Out of the five novel mutations identified in this investigation, four new alleles (le484,667, le484,667,808, Le304, and Le370) were determined in the Xhosa population and two new alleles (le202,314,484 and Le304) in the Caucasian population. The determination of alpha(1,3/1,4)fucosyltransferase activity, after transfection of plasmids containing the new alleles into COS7 cells, suggested that alleles le484,667 and le484,667,808 encoded an inactive enzyme, and that alleles Le304 and Le370 encoded a functional enzyme. In addition, we also examined the incidence of five common alleles, Le59, le59,508 le59,1067, le202,314, and le1067 in two populations by the polymerase chain reaction/restriction fragment length polymorphism method and compared differences in the allele frequencies of FUT3 among three ethnic groups (Orientals, Africans, and Caucasians).

Alleles↗

PubMed1998

Cold injury to nerves is not due to ischaemia alone.

The effect of cold on nerve fibre populations may be quite selective. Thus it was possible in the present study, with precise timing of a non-freezing cold nerve injury, to destroy myelinated fibres, but leave unmyelinated fibres intact. The aetiology of this cold-induced selective peripheral nerve pathology remains controversial, but recent evidence suggests that ischaemia plays an important role. To investigate this matter further, we have sought to determine whether ischaemia alone might account for such discrete nerve pathology, in a series of non-freezing cold injury paradigms. Compared with previous 'pure' ischaemic peripheral nerve models, notable differences were found in the present paradigms (early post-ischaemic luxury perfusion and severe nerve pathology), suggesting a multifactorial aetiology. Nonetheless a tight correlation was evident, with increasing duration of cold injury resulting in a progressively more severe reduction in post-cold nerve blood flow. Given these findings, we would propose that the pathological basis of non-freezing cold nerve injury is one of ischaemia, accelerated and enhanced by direct cold injury.

Action Potentials↗