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Biomedical subjects

R Zhao

Publications and source records attributed to R Zhao.

At least 109 records · Page 6Linked to original sources
PubMed1999

Insecticidal activity of transgenic tobacco plants expressing both Bt and CpTI genes on cotton bollworm (Helicoverpa armigera).

Transgenic tobacco plants expressing both Bacillus thuringiensis (Bt) insecticidal protein and cowpea trypsin inhibitor (CpTI) genes was used to evaluate the insecticidal activity on the cotton bollworm (Helicoverpa armigera) compared with transgenic tobacco with Bt insecticidal protein gene alone. Mortality of first to third instar larvae fed on transgenic two genes tobacco for three days was significantly higher than that fed on transgenic Bt tobacco. First to fourth instar larvae fed on transgenic two genes tobacco continuously could not survive until pupation. Second instar larvae were fed on transgenic tobacco plants for three days and then were transferred to an artificial diet. The efficacy of transgenic two genes tobacco on mortality, larvae weight, percentage of pupation, and time to pupation were significantly higher than that of transgenic tobacco with Bt insecticidal protein gene alone. The results with transgenic tobacco as model plant were valuable for other crops both for the enhancement of insecticidal efficacy and for the delay of insect adaptation to transgenic Bt crops.

Animals↗
PubMed1999

[Morphological study of CD3+ dendritic epidermal T cells in human skin and scar].

OBJECTIVE: To investigate the CD3/TCR-bearing T cell in the epidermis and explore the influence of the dendritic epidermal T cells on regeneration and differentiation of epidermal cells. METHODS: The CD3/TCR-bearing T cells in epidermis of human skin and cicatrix were examined by means of histomorphology and immunohistochemistry. RESULTS: It was found that the density of CD3/TCR-bearing T cells in human skin and scar tissue had great dissimilarity. CD3+ dendritic epidermal T cells increased in hyperplastic scar. Such result was not observed in atrophic scar. CONCLUSION: Our findings indicate CD3+ dendritic epidermal T cells regulate the generation and differentiation of epidermal cells. CD3+ dendritic epidermal T cells may play an important role in the maintenance of the morphology of epidermal tissue.

Adult↗
PubMed1999

[Studies on the expression of complement regulatory proteins in three kinds of stem cell defect anemias and its clinical implications].

OBJECTIVE: To investigate the expression of membrane associated complement regulatory proteins (CRP)--CD55 and CD59 on the peripheral blood cells in patients with paroxysmal nocturnal hemoglobinuria (PNH), aplastic anemia(AA) and myelodysplastic syndrome (MDS) and its clinical implications. METHODS: Expression of CD55 and CD59 on neutrophils, lymphocytes and erythrocytes was analyzed with flow cytometry, using FITC and PE labeled anti-CD55 and CD59 monoclonal antibodies. RESULTS: CD55 and CD59 expression on neutrophils was significantly decreased in 21 PNH patients (including 2 cases of AA-PNH syndrome). CD59- cells in neutrophils were constantly in excess of 10% in all of the PNH patients. Reduction in CD59 expression on erythrocytes was related to the severity of the disease. CD55- neutrophils were also significantly increased in PNH patients but with a greater variation. Expressions of CD55 and CD59 on neutrophils were remarkably decreased in 31 AA patients but to a less extent as compared to PNH. No significant difference in the expressions of CD55 and CD59 was found in all the 21 MDS patients. CONCLUSION: Expression of CRP is reduced in PNH and its related disorder-AA but remains unchanged in MDS. Flow cytometric analysis of complement regulatory proteins is of value in diagnosis and differential diagnosis of PNH, AA and MDS. In terms of diagnostic sensitivity and specificity, CD59 is superior to CD55, and neutrophil is superior to lymphocyte and erythrocyte.

Adolescent↗
PubMed1999

[Experimental study on effect of guyubao in promoting the fracture healing in kidney deficiency rabbits].

OBJECTIVE: To study the effect of Guyubao (GYB) in promoting the fracture healing of Kidney deficiency (KD) rabbits. METHODS: Fifty-seven rabbits were randomly divided into three groups: The blank group (A), the control group (B) and the experimental group (C). After the periosteum was peeled off, 0.73 cm middle section defects on both radius were removed. One week after operation, the experiment was begun: Group A was fed normally; group B fed normally plus 6 mg/(kg.d) prednisolone; group C fed with food mixed with GYB and 6 mg/(kg.d) prednisolone. The general state and body weight were observed. The rabbits were sacrificed at three and six weeks after the beginning of experiment. Both radius were observed with X-ray and histologic examination. RESULTS: In group A, no KD appeared, group B gradually developed KD, and mild KD appeared in group C but adjusted rapidly. The healing of radial defect in order were C, A, B from higher to lower degree. CONCLUSION: The results revealed that the GYB could correct the KD and promote fracture healing.

Animals↗
PubMed1999

[Effects of methylmercury on embryonic cell behavior and expression of related gene].

OBJECTIVE: To explore the mechanism of embryonic developmental toxicity of methyl mercury at cellular and gene levels. METHODS: Effects of methylmercury on embryonic cell behavior and gene expression in rats were observed with in vitro (0, 0.05, 0.10, 0.20, 0.40, 0.80 and 1.60 mg/L of methylmercury) and in vivo (0, 0.2, 0.4, 0.8, 1.6 and 3.2 mg/L of methylmercury) rat models, in situ hybridization and TdT-induced dUTP nick end labeling techniques. RESULTS: Methylmercury could pass through yolk-sac placenta quickly, and inhibit placenta development and blood vessel differentiation there at higher concentration. There was a dose-response relationship between concentration of methylmercury and its embryonic developmental toxicity. Its developmental toxicity mainly characterized as patent neural tube and anomalous flexion. Methylmercury could induce excessive apoptosis of embryonic cells, inhibit apparently the synthesis of cellular DNA and RNA and damage its cellular ultrastructure. It also could induce significantly the expression of heat shock protein 70 mRNA and inhibit the expression of fibronectin and p16 mRNA. There was relationship between heat shock protein 70 mRNA, Ca(2+), apoptosis and teratogenesis. CONCLUSION: Disturbance of embryonic cell behavior and related gene expression played important roles in developmental toxicity caused by methylmercury.

Animals↗
PubMed1999

[The application of artificial neural network in QSAR research of PCDD].

The study of QSAR between molecular structure and retention behavior of solutes is an important topic of chromatographic basic theory. PCDD (polychlorinated dioxin) is a kind of important environmental toxin. The basic skeleton of PCDD is [symbol: see text]. PCDDs are all chlorine substituted, so they are only different from each other in the number and position of chlorine substitutents on the skeleton. There are 76 kinds of homologues (1 to 8 chlorine substituent) for 3, 4, 5 and 6 chlorine substituted compounds including more than ten kinds of isomerides. In this paper, the description of molecular structure and feature selection have been investigated. Artificial neural network (ANN) is used to relate the molecular structure and retention time of PCDD. The predicted results of 49 PCDDs retention time by ANN are listed. It was shown that as to the relative error more than 95% data was less than 10% and more than 80% data was less than 5%.

Chromatography↗
PubMed1999

[Expression of CD44v and nm23-H1 proteins in laryngeal carcinoma and its correlation with clinical significance].

OBJECTIVE: To investigate the correlation between the expression of two gene proteins and their clinical significance in laryngeal carcinoma. METHODS: Sixty fresh laryngeal carcinoma samples were analyzed and 20 para-carcinoma tissue and 12 normal laryngeal mucosa samples were studied as controls. All specimens were collected from patients operated on from 1996 to 1998 in the same department (including 52 males and 8 females, age ranged from 41 to 77). The quantitative expression of CD44v and nm23-H1 proteins was analyzed by flow cytometry (FCM) and immunofluorescence technique. RESULTS: 1. Higher level expression of CD44v and nm23-H1 proteins was detected in the laryngeal carcinoma specimen than in normal laryngeal mucosa. 2. The expression of CD44v protein was positively correlated with the metastasis, clinical staging and pathological classification; but not correlated with sex, age, tumor size, course of the disease, T classification and category of laryngeal cancer. 3. The expression of nm23-H1 protein was inversely correlated with metastasis and clinical staging while positively correlated with age and tumor size; no significant relations were found between the expression and the sex and course of the disease, T classification and category of laryngeal cancer. 4. There was an inverse correlation between the protein expression of CD44v and nm23-H1. CONCLUSION: CD44v and nm23-H1 probably play an important regulating role in the metastasis of laryngeal carcinoma.

Adult↗
PubMed1998

Artificial neural network classification based on capillary electrophoresis of urinary nucleosides for the clinical diagnosis of tumors.

Nucleosides in human urine have been studied frequently as a possible biomedical marker for cancers, acquired immune deficiency syndrome (AIDS) and the whole-body turnover of RNAs. A capillary electrophoretic method that can quantitatively analyze urinary normal and modified nucleosides in less than 40 min with a good resolution and sufficient sensitivity has been developed. Twelve kinds of normal and modified nucleosides were determined in urine samples from 25 healthy persons and 25 cancer patients of 14 kinds of cancers. Artificial neural networks have been used as a powerful pattern recognition tool to distinguish cancer patients from healthy persons. The recognition rate for the training set reached to 100% and above 85% of the members in the predicting set were correctly classified. In addition, the neural network technique was compared with methods of the principal component analysis and the canonical discriminant analysis. The results demonstrate that the predictive ability of the artificial neural network is stronger than the others in this study.

Biomarkers, Tumor↗
PubMed1998

Purification and cloning of PZR, a binding protein and putative physiological substrate of tyrosine phosphatase SHP-2.

Overexpression of a catalytically inactive mutant of tyrosine phosphatase SHP-2 in 293 cells resulted in hyperphosphorylation of a glycoprotein specifically associated with the enzyme. The protein has been purified to near homogeneity. Based on the amino acid sequences of peptides obtained from the protein, a full-length cDNA was isolated. The cDNA encodes a protein with a single transmembrane segment and a signal sequence. The extracellular portion of the protein contains a single immunoglobulin-like domain displaying 46% sequence identity to that of myelin P0, a major structural protein of peripheral myelin. The intracellular segment of the protein shows no significant sequence identity to any known protein except for two immunoreceptor tyrosine-based inhibitory motifs. We name the protein PZR for protein zero related. Transfection of the PZR cDNA in Jurkat cells gave rise to a protein of expected molecular size. Stimulation of cells with pervanadate resulted in tyrosine phosphorylation of PZR and a near-stoichiometric association of PZR with SHP-2. Northern blotting analyses revealed that PZR is widely expressed in human tissues and is particularly abundant in heart, placenta, kidney, and pancreas. As a binding protein and a putative substrate of SHP-2, PZR protein may have an important role in cell signaling.

Amino Acid Sequence↗
PubMed1998

A mutated murine reduced folate carrier (RFC1) with increased affinity for folic acid, decreased affinity for methotrexate, and an obligatory anion requirement for transport function.

In an ongoing study of structure-function relationships of the murine reduced folate carrier 1 (RFC1), a glutamate to lysine mutation at amino acid 45 was identified in a methotrexate (MTX)-resistant L1210 clonal variant in which MTX and 5-formyltetrahydrofolate (5-CHO-THF) influx was markedly decreased. The characteristics of the mutated carrier, RFC1-E45K, were studied by cDNA transfection into the murine MTXrA line in which endogenous carrier is not functional. Folic acid influx doubled in the transfectant MTXrA-E45K as compared with L1210 or MTXrA cells; in contrast, MTX and 5-CHO-THF influx was only 14 and 27% that of L1210 cells, respectively. 5-CHO-THF influx in MTXrA-E45K cells was characterized by a 12- and 3.6-fold decrease in influx Vmax and Kt respectively, relative to L1210 cells. The folic acid influx Ki in L1210 cells was more than 50-fold greater than that of MTX based upon inhibition of 5-CHO-THF influx. In comparison, the mutated carrier had comparable affinities for folic acid and MTX in MTXrA-E45K cells due to a 7-fold decrease in the folic acid influx Ki and 7-fold increase in the MTX influx Ki. Transport via native RFC1 is inhibited by a variety of anions in L1210 cells associated with an increase in influx Kt. However, influx of 5-CHO-THF in MTXrA-E45K cells in a HEPES buffer (9 mM chloride) was decreased by 70% due to a 3-fold fall in the Vmax. In the complete absence of chloride (K+-HEPES-sucrose buffer) 5-CHO-THF influx was only 10% that in HBS buffer. 5-CHO-THF influx was restored by addition of chloride, fluoride, or nitrate but not by sulfate, phosphate, or ATP which were all inhibitory over a broad range of concentrations. The data suggest that substitution of a positive for a negative amino acid at position 45 results in the loss of RFC1 mobility in the absence of small inorganic anions that bind to, and neutralize the positive charge on, the lysine residue. Inhibition by higher charged anions may be due to interactions at another carrier site present in both the mutated and wild type carrier. This and other studies suggest that amino acids in the first predicted transmembrane domain play an important role in determining the spectrum of affinities for, and mobility of, RFC1 and is a cluster region for mutations when cells are placed under selective pressure with antifolates that utilize RFC1 as the major route of entry into mammalian cells.

Amino Acid Substitution↗
PubMed1998

Ginseng improves strategic learning by normal and brain-damaged rats.

Adult rats were prepared with either sham or medial prefrontal cortex lesions and administered, beginning on the third post-operative day, either, 0, 40, or 80 mg kg-1 crude ginseng extract suspended in saline daily for the next 30 days. Later, kinetic functions were evaluated on an elevated rotating rod. No long-term influences of the treatments were observed on this task. Significant positive influences of ginseng were observed in the position reversal task. The learning deficits observed in the saline control brain-damaged rats were significantly attenuated in the ginseng-treated animals. An analysis of trial 2 response accuracy across reversals revealed enhanced cognitive abilities (i.e. acquisition of a win-stay, lose-shift strategy) in both the brain damaged and sham control rats administered ginseng. Generally, administration of the higher dose resulted in better performance in the learning paradigm. The exact mechanism responsible for these promising results remains to be discovered. Several possible mechanisms are discussed.

Analysis of Variance↗
PubMed1998

[Detection of hemophilia A carriers by PCR analysis of hind III polymorphism in the factor VIII gene].

OBJECTIVE: To explore a scheme of using PCR analysis in the detection of carriers of Hind III polymorphism of factor VIII gene of hemophilia A. METHODS: Implicating intron 19 of the factor VIII gene of 6 patients with the hemophilia A and 207 unrelated X-chromosomes were amplified by PCR and were analysed by means of Amp-RFLPs of Hind III. RESULTS: The incidence of the polymorphic Hind III sites in the given population was found to be 0.29. The frequence of the Hind III heterozygotes in women calculated according to Hardy-Weinberg equation was 0.41, which proved to be informative enough for carrier detection and prenatal diagnosis of hemophilia A. 2 out of 6 families (33%)examined in this study were informative. CONCLUSION: The new scheme proved to be effective for hemophilia A carrier detection and prenatal diagnosis.

Deoxyribonuclease HindIII↗
PubMed1998

A reduced folate carrier mutation produces substrate-dependent alterations in carrier mobility in murine leukemia cells and methotrexate resistance with conservation of growth in 5-formyltetrahydrofolate.

With 5-formyltetrahydrofolate (5-CHO-THF) as the folate source a methotrexate (MTX) transport-deficient murine leukemia cell line, L1210-G1a, was isolated after chemical mutagenesis and MTX selection. This cell line was 10-fold resistant to MTX in comparison to parental L1210 cells, yet the EC50 for 5-CHO-THF was increased by a factor of only 2. The initial uptake of MTX, at a concentration of 1 microM, was decreased by a factor of 40, whereas influx of 5-CHO-THF dropped by a factor of only 8. This difference in initial uptake rates was attributed solely to changes in influx Vmax without a significant change in Km. Whereas the RFC1 mRNA level in L1210-G1a cells was indistinguishable from that of parental L1210 cells, a serine to asparagine substitution was identified at amino acid 46 within the first predicted transmembrane domain. This was a result of a homozygous mutation of G-->A in the genome. Transfection of the mutated RFC1 cDNA into MTXrA cells, which lack functional endogenous carrier, resulted in a clonal derivative MTXrA-S46N. The increase in influx of 5-CHO-THF and 5-CH3THF was 5 and 13 times greater than that for MTX in the transfectant, consistent with the influx ratio in the L1210-G1a line. The functional expression of the mutated RFC1 reduced the growth requirement for 5-CHO-THF by a factor of 30, compared with only a 3-fold decrease in the MTX IC50. This represents the first reported RFC1 mutation that confers resistance to MTX due to a markedly impaired influx with relative conservation of reduced folate transport. The kinetic changes are consistent with a substrate-dependent alteration in carrier mobility that favors reduced folates over MTX. These changes may account for the development of MTX resistance due to impaired drug transport in vivo, allowing tumor cells to meet their folate requirement with 5-CH3THF, the predominant blood folate.

Animals↗
PubMed1998

Architectural features of the Salmonella typhimurium flagellar motor switch revealed by disrupted C-rings.

The three-dimensional surface topology of rapid-frozen Salmonella typhimurium flagellar hook basal body complexes was studied by stereo-examination of thin-film metal replicas. The complexes contained the extended cytoplasmic structure, composed of the switch complex proteins; FliG, FliM, and FliN. Distinct nanometer-scale element arrays, separated by grooves, defined the outer surface of the cytoplasmic (C-) ring. The number of array elements was comparable to previously determined FliG and FliM copy numbers in the basal body. In addition to basal body complexes lacking C-rings, complexes containing incomplete C-rings were identified. The incomplete C-rings had lost segments of the proximal array. Basal bodies with the distal C-ring array alone were not found. These findings are compatible with the spatial organization of the flagellar switch suggested by previous biochemical data.

Bacterial Proteins↗
PubMed1998

[The role of diet consultation on improvement of the diet nutrition in pregnant women].

OBJECTIVE: To study the improvement of the intakes of various nutrients including protein, fat, carbohydrate, fibers, calcium, iron, zinc et al, in pregnant women after appropriate diet consultation by doctors. METHODS: 100 cases of pregnant women coming to our diet consultation clinic were randomly selected, in which 50 cases (control group) came for the first time and another 50 cases (study group) were for the third visit at least. The diet nutrition of the study group after the second consultation were compared with that before consultation and with concurrent control group. RESULTS: After diet consultation, except for retinol, the intake of various nutrients, including calorie intake, protein, fibers, magnesium, calcium, phosphorus, iron, zinc, vitamin E, riboflavin, thiamine, nicotinic acid, in study group were significantly improved compared with that of the study group before diet consultation and of the control group (P < 0.01). CONCLUSION: Diet consultation plays excellent role in promoting scientific and appropriate nutrients intake of pregnant women.

Adult↗
PubMed1998

Steroid-resistant asthma: effects of glucocorticoids on interleukin-4 and interleukin-5 gene expression.

OBJECTIVE: To investigate the role of interleukin-4 (IL-4) and interleukin-5 (IL-5) in the pathogenesis of steroid-resistant (SR) asthma. METHODS: Fifteen patients with SR asthma and 15 patients with steroid-sensitive (SS) asthma were selected based on their clinical responses to prednisone therapy. The peripheral blood mononuclear cells (PBMCs) were obtained and incubated with phytohemagglutinin (PHA) in vitro for 48 h in the presence or absence of dexamethasone (10(-7) mol/L). Expressions of IL-4 and IL-5 mRNA in PBMCs were determined by reverse transcription-polymerase chain reaction (RT-PCR), and mRNA positive PBMCs for IL-4 and IL-5 were measured with in situ hybridization using digoxin-labeled cDNA probes. RESULTS: In the absence of dexamethasone, there was no significant difference in the expressions of IL-4 and IL-5 mRNA between SR and SS asthmatics, and the numbers of mRNA positive cells for IL-4 and IL-5 were also similar between these two groups, however, in the presence of dexamethasone (10(-7) mol/L), expressions of IL-4 mRNA (P < 0.01) and IL-5 mRNA (P < 0.05) were significantly inhibited in SS asthmatics, but not in SR asthmatics (P > 0.05). The numbers of IL-4 and IL-5 mRNA positive cells decreased from 5.50 +/- 1.60 to 2.27 +/- 0.98 (P < 0.01) and from 5.03 +/- 1.29 to 1.67 +/- 0.70 (P < 0.01), respectively in SS asthmatics, but in the patients with SR asthma, there was no significant change in the number of cells expressing mRNA for IL-4 or IL-5. CONCLUSION: The gene expression of IL-4 and IL-5 in SR asthma was not inhibited by dexamethasone at the concentration of 10(-7) mol/L. It is suggested that the relative unresponsiveness of T cells to glucocorticoids and persistent production of cytokines may be one of the mechanisms of steroid resistance in asthma.

Adult↗
PubMed1998

[Relationship between lipometabolic disorder in stroke with TCM syndrome differentiation and typing].

OBJECTIVE: To analyse the relationship between lipometabolic disorder in stroke with TCM Syndrome Differentiation and Typing. METHODS: The serum lipid, lipoprotein and apo-lipoprotein level of TCM treated group (142 cases) and control group (100 cases) were determined. The patients were subdivided into three Type-groups according to TCM Syndrome Differentiation: Phlegm-Dampness Stagnation (PDS), Yin Deficiency with Yang Hyperactivity (YDYH) and Qi Deficiency with Blood Stasis (QDBS) group. RESULTS: The results showed that the level of TC, TG, HDL, LDL, apoA1, apoB and apoA1/apoB were significantly different in PDS and QDBS as compared with control group (P < 0.05, P < 0.01, respectively), while lipometabolic disorder of PDS was most serious in TCM Syndrome Differentiation of stroke. The level of TG, apoA1/apoB were significantly different in YDYH in comparing with control group (P < 0.05). While the level of TC, HDL, LDL and apoB were insignificantly different than those of control group (P > 0.05). CONCLUSIONS: This study showed that lipometabolic disorder of stroke were correlated with Syndrome Differentiation of TCM. Stroke with PDS and QSBS should give removing Phlegm-Dampness, dredging Meridian and removing blood stasis treatment besides routine treatment.

Adult↗