Biomedical subjects

X Zhou

Publications and source records attributed to X Zhou.

At least 289 records · Page 16Linked to original sources

PubMed2000

[Expressional change of brain-derived neurotrophic factor in adult cat spared DRG].

UNLABELLED: This investigation was aimed to search the expressional change of BDNF in the normal and spared L6DRG. The L6DRGs from 20 adult male cats (5 normal cats, 15 unilateral L6 spared roots cats allowed to survive 3 days, 6 days and 12 days respectively) were embedded in paraffin, using immunohistochemical reaction to detect BDNF. RESULTS: 1. Normal DRG neurons were divided into three categories(large, medium and small) with the cell body diameter 32 microns and 44 microns as the dividing lines. 2. There are 50.87% BDNF positive neurons in normal L6DRG. After operation, the number of BDNF positive neurons of the operated side DRG significantly increased, especially 6 days(76.70%). Normal and postoperative BDNF positive neurons were mainly small neurons. After partial section of DRG, the expression of BDNF in spared DRG neurons increased, which might be involved in promoting collateral sprouting of spared root in spinal cord and rescuing the dorsal horn neurons from partial deafferentation.

Animals↗

PubMed2000

[A comparative study of fatty acids in human dental plaque and whole saliva].

This study was intended to carry out qualitative and quantitative analyses of fatty acids in plaque and saliva. Samples of plaque and saliva from 10 volunteers were analyzed for fatty acids by gas-chromatography and gas-chromatography/mass spectrometry. The sample preparation procedure allowed specimens from individual volunteers to be analyzed. The results showed the plaque contained C14.0, C15.0, C16.0, C16.1, C18.0, C18.1, C18.2, C20.0 acids and the saliva contained C16.0, C18.0, C20.0, C16.1, C18.1, C18.2 acids. The concentration of fatty acids in plaque was 35.17 +/- 7.723 micrograms/mg (dry weight); and that in saliva was 13.23 micrograms/ml. Quantitatively, C18.1 and C16.0 acids were the largest fatty acids. These findings imply that the origin and role of the fatty acids in plaque and saliva may be different.

Adolescent↗

PubMed2000

[Fasting serum glucose and its related indexes in 1477 middle aged and elderly people].

In order to study the relationship between higher fasting serum glucose (FSG) and other related indexes in middle aged and elderly people, FSG, triglyceride, cholesterol, urate and insulin of serum, blood pressure and body mass index(BMI) of 1477 men and women over 40 years of age were analyzed. The results showed that the level of FSG rised with the increase of age. The relations between FSG and cholesterol, urate, blood pressure and BMI were significant. The levels of cholesterol, urate, blood pressure and BMI in the abnormal FSG group were higher than those in the normal FSG group. There were positive relationships between FSG and cholesterol, urate, blood pressure, BMI, age, waist and buttock circumferences. The factors related to FSG were age, BMI, cholesterol and diastolic pressure by stepwise regression.

Age Factors↗

PubMed2000

[Establishment of a GC and GC/MS method for analysis of fatty acids in human dental plaque].

OBJECTIVE: To study the composition of fatty acids in human dental plaque, a Gas Chromatography (GC) and Gas Chromatography/Mass Spectrometry (GC/MS) method was developed. METHODS: The C17:0 was internal standard and the C16:0 was test standard. Samples of plaque were methanolysis to be fatty acids methyl ester before detection. GC with OV-1 separated the sample for a quantitative analysis. The column size was 25 m x 25 mm. The temperature program was from 80 degrees C to 260 degrees C with 12 degrees C/min. The sample separation was carried out at fused silica capillary column with OV-1 for qualitative analysis by GC/MS. The column size was 23 m x 0.23 mm. The temperature program was from 40 degrees C to 240 degrees C at 6 degrees C/min. RESULTS: The linear regression equation was y = 0.0138X-0.1182, r = 0.9945, recovery was 90.18%-103.6%, CV intro-day was 2.60, 1.61, 2.20; CV inter-day was; 2.71, 1.69, 1.61. The lowest limit of detection was 0.6 ug. The GC and GC/MS diagram showed that internal standard and fatty acids of plaque have good separation. CONCLUSION: The method is simple, rapid accurate, and is useful to carry out qualitative and quantitative analyses of fatty acids in dental plaque.

Chromatography, Gas↗

PubMed2000

[A study of the mechanism of effects of solution containing trace elements on remineralization layer formation of enamel carious lesions].

OBJECTIVE: To study the effects of several remineralization solutions with different composition on the artificial demineralization lesions of bovine enamel and the mechanism of remineralization layer formation. METHODS: 36 bovine teeth were selected and artificial carious lesions were formed with lactic acid gel. Then all specimens were divided into 4 groups which contained no fluoride, fluoride, fluoride-calcium-phosphate-tin, and de-ionic water separately, and the de-ionic group was taken as control. The structure and composition of the sediments on the enamel surface were evaluated and detected by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Histological change of enamel section was examined by polarized microscopy. RESULTS: Compared with the control group, all the solutions had remineralization effects, especially the solutions containing trace elements. XPS showed that there were sediments formed on the surface of carious lesion, the compositions of the sediments were CaF2, HAP and non-specifically absorbed fluoride (NSAF). Irregular, crystal deposits were also found under SEM on the enamel surface. The polarized microscopy results showed that the observed demineralization areas decreased after exposure to the solutions. CONCLUSION: Solutions containing fluoride and trace elements were effective on remineralization. The possible mechanism is that CaF2 and NSAF, instead of FA formed in the remineralization layer. Moreover, the remineralization effects of the fluoride solutions containing trace elements are more outstanding than that without trace elements. The potential mechanism is the synergistic action of fluoride and trace elements.

Animals↗

PubMed2000

[The effects of tea polyphenols on the adherence of cariogenic bacterium to the salivary acquired pellicle in vitro].

OBJECTIVE: It has been proved that tea polyphenols (TP) can inhibit the sucrose-dependent adherence of oral cariogenic bacterium to the tooth surface. This study is carried on to investigate the effects of tea polyphenols on the preliminary adherence of main cariogenic bacterium to salivary acquired pellicle and reveal the anticarious mechanisms of tea polyphenols further. METHODS: The hydroxyapatites were coated by saliva to form S-HA, an in-vitro model of experimental pellicle. Streptococcus mutans 3a3 and Actinomyces viscosus ATCC 19246 were chosen as the main cariogenic bacterium, and the microorganisms were radiolabelled by growing them in TPY culture medium supplemented with 3H-thymidine. Tea polyphenols solution was prepared, the concentrations of which were 0.5, 1.0, 2.0 and 4.0 mg/ml respectively. Two parts of inhibited adherence tests were done with TP-treated S-HA or TP-treated bacterium. In the first one, S-HA was immerged into the TP solution of different concentrations for 1 h before the attachment of bacterium. In the other, the bacterium were mixed with the TP solution for 1 h and then centrifuged and washed before bound to S-HA. The whole process was carried on in KCl buffer solution. The number of 3H-thymidine-labelled bacterium which attached to S-HA were determined by scintillation counting. RESULTS: In both the two parts of this study, tea polyphenols solution, the concentrations of which were changed from 1.0 to 4.0 mg/ml, could decrease the number of S. mutans 3a3 and A. viscosus ATCC 19246, and the inhibition rates rose with the increase of the concentrations of TP solution. But the inhibitory effects of 0.5 mg/ml TP solution were inconsistent in different tests. The results showed that 1.0-4.0 mg/ml TP solution could inhibit the attachments of S. mutans and A. viscosus to S-HA effectively. The inhibitory functions of tea polyphenols were so obvious that in some experiments, while the concentrations of TP solution were changed from 2.0 to 4.0 mg/ml, the number of 3H-thymidine-labelled bacterium which attached to S-HA was even less than that of the same bacterium which attached to naked HA. CONCLUSION: Tea polyphenols can inhibit the preliminary adherence of Streptococcus mutans and Actinomyces viscosus to S-HA effectively. TP may prevent enamel from caries by decreasing the adherence of main cariogenic bacterium to salivary acquired pellicle.

Actinomyces viscosus↗

PubMed2000

[The effects of tea polyphenols on the adherence of cariogenic bacterium to the collagen in vitro].

OBJECTIVE: In the first phase of our study, it has been proved that tea polyphenols (TP) can inhibit the preliminary adherence of oral cariogenic bacterium to salivary acquired pellicle. This study is carried on to investigate the effects of tea polyphenols on the preliminary adherence of main cariogenic bacterium to collagen I and reveal the anticarious mechanisms of tea polyphenols further. METHODS: Tea polyphenols solution was prepared firstly, the concentrations of which were 0.5, 1.0, 2.0 and 4.0 mg/ml. An in-vitro model of experimental pellicle(C-HA) was formed by immerging the hydroxyapatites in 250 micrograms/ml collagen I solution for 1 h. Streptococcus mutans 3a3, Actinomyces viscosus ATCC 19246 and Lactobacillus ATCC 4546 were chosen as the main cariogenic bacterium and radiolabelled by growing them in TPY culture medium supplemented with 3H-thymidine. Two parts of inhibited adherence tests were done with TP-treated C-HA or TP-treated bacterium respectively. In the first one, C-HA was immerged into the TP solution of different concentrations for 1 h before the attachment of bacterium. In the other, the bacterium were mixed with the TP solution for 1 h and then centrifuged and washed before bound to C-HA. KCl buffer solution provided a steady condition to the whole process. Finally, the number of 3H-thymidine-labelled bacterium which attached to C-HA were determined by scintillation counting. RESULTS: In both the two parts of this study, tea polyphenols solution, the concentrations of which were changed from 1.0 to 4.0 mg/ml could inhibit the attachments of S. mutans 3a3, A. viscosus ATCC 19246 and Lactobacillus ATCC 4546 to C-HA effectively, and the inhibition rates rose with the increase of the concentrations of TP solution. But the inhibitory effects of 0.5 mg/ml TP solution were inconsistent in different tests. The inhibitory functions of tea polyphenols were so prominent that in some experiments, while the concentrations of TP solution were higher than 2.0 mg/ml, the number of 3H-thymidine-labelled bacterium which attached to C-HA was even less than that of the same bacterium which attached to naked HA. These results showed that TP had the remarkable inhibitory efficiency on the attachments of S. mutans, A. viscosus and Lactobacillus to C-HA. CONCLUSION: Tea polyphenols can inhibit the preliminary adherence of Streptococcus mutans, Actinomyces viscosus and Lactobacillus to C-HA effectively. TP may prevent dentine from caries by decreasing the adherence of main cariogenic bacterium to collagen.

Actinomyces viscosus↗

PubMed2000

[Effect of calcium on adherence of Streptococcus mutans MT6R(serotype c) surface protein P1].

OBJECTIVE: To study effects of calcium on the adherence of Streptococcus mutans MT6R(serotype c) surface protein P1 to saliva-coated hydroxyapatite(S-HA). METHODS: The surface protein P1 of Streptococcus mutans MT6R was purified by PAGE and labeled with 131I(131I-P1). The adherence amount of 131I-P1 to S-HA in different calcium concentration liquid was measured. RESULTS: The amount of 131I-P1 adherence to S-HA in 0, 0.1, 0.25, 0.5, 1.0, 1.5, 2.0 mmol/L, and calcium was 7175 + 183, 7516 + 192, 8850 + 215, 9335 + 204, 10087 + 228, 10179 + 224 and 10200 + 317 cpm, respectively(P < 0.01). The calcium concentration from 0 to 1.0 mmol/L, the amount of 131I-P1 adherence was increased statistically(P < 0.05), calcium concentration from 1.0 mmol/L to 2.0 mmol/L, the amount of 131I-P1 adherence was increased unstatistically(P > 0.05). CONCLUSION: Calcium promoted the adherence of surface protein P1 to the S-HA. This result suggested that calcium was involved in the adherence of Streptococcus mutans MT6R (serotype c) surface protein P1.

Bacterial Adhesion↗

PubMed2000

A preliminary study of the quantitative structure-retention relationship of ginsenosides in normal phase thin-layer chromatography.

The TLC retention of ten ginsenosides has been determined on silica gel layers developed with chloroform-ethyl acetate-methanol-water (15:40:22:10, V/V) as the mobile phase. For the quantitative structure-retention relationship (QSRR) study seventeen structure parameters of the ten ginsenosides were calculated, including topologic indices and physicochemical properties. Particularly, a novel parameter "E" was presented according to the differences of the parent substances of which the ginsenosides are composed. Of these parameters, Aw, 0B and E were selected by optimization and employed in the derived multi-parameter regression equation. The relationships between the retention and the molecular structures have been discussed.

Chemical Phenomena↗

PubMed2000

[Practical optimization of the two-dimensional thin-layer chromatographic separation of ginsenosides].

A computer-assisted method is presented for optimization of mobile phase selection for separation of the mixture of ginsenosides in two-dimensional TLC. This method bases on the correlation between the proportions of mobile phases and the retention values Rf of ginsenosides, and uses Dmin(the minimum distance of two spots) as the selection criterion with a two factor (Xs, Ys) statistical scanning technique. The experimental results, from which we observe that more new spots are separated than on one-dimensional TLC, are in excellent agreement with the predicted results.

Chromatography, Thin Layer↗

PubMed2000

[A clinical study on PA-MSHA vaccine used for adjuvant therapy of lymphoma and lung cancer].

The objective of this study was to evaluate the effectiveness and safety of pseudomonas aeruginosa MSHA vaccine (PA-MSHA vaccine) used as an immune modulator. The study was carried out after the design of a non-blind, randomized controlled trial. The malignant lymphoma patients were divided into experiment group (45 cases) and control group (43 cases). Likewise were distributed the lung cancer patients: 44 cases in experiment group and 45 cases in control group. The two experiment groups received chemotherapy + PA-MSHA vaccine. The two control groups were given chemotherapy alone. The results showed that the clinical efficacy rate was 95.56% for the exp. group and 69.77% (P < 0.01) for the control group of the malignant lymphoma cases; the clinical efficacy rate was 59.09% for the exp. group and 42.22% (P < 0.01) for the control group of the lung cancer cases. The infection rate was 17.78% for the exp. group and 37.21% (P < 0.05) for the control group of the malignant lymphoma cases; the infection rate was 15.91% for the exp. group and 40.00% (P < 0.05) for the control group of the lung cancer cases. The comprehensive immune effectiveness rates for the exp. group and control group of the malignant lymphoma cases were 77.78% and 23.26% (P < 0.01) respectively. The comprehensive immune effectiveness rates for the exp. group and control group of the lung cancer cases were 84.09% and 35.56% (P < 0.01) respectively. Adverse reactions were found in 5 cases, of which, one was given medical care while the others automatically recovered. These results indicate that PA-MSHA vaccine, as a new kind of immune modulator, can improve the effectiveness of treatment for tumor with low adverse reaction rate.

Adjuvants, Immunologic↗

PubMed2000

[A comparative study on the capacities of different strains of Streptococcus sanguis for P-aminobenzoic acid production].

This study was intended to compare the capacities of different strains of Strep, sanguis for P-Aminobenzoic acid (PABA) production. The synthesis of PABA during the growth of four strains of Strep. sanguis was measured by the reversed-phase high-performance liquid chromatographic method. The results showed that the concentrations of PABA synthesized by S. sanguis 10556, S. sanguis 10557, S. sanguis S34 and S. sanguis H7-4. Were 1.979 +/- 0.081 micrograms/ml, 1.383 +/- 0.193 micrograms/ml, 1.983 +/- 0.052 micrograms/ml and 1.032 +/- 0.229 micrograms/ml, respectively, and in term of PABA concentration, S. sanguis 10556 was significantly different from S. sanguis 10557 and S. sanguis H7-4; S. sanguis S34 was significantly different from S. sanguis 10557 and S. sanguis H7-4. No significant difference was found between S. sanguis 10556 and S. sanguis S34, nor between S. sanguis 10557 and S. sanguis H7-4, either. In conclusion, the method is simple, rapid and accurate. S. sanguis did synthesize PABA, and the difference in ability for PABA formation existed among the four strains of S. sanguis. This study is helpful to researches on the symbiosis between S. sanguis and S. muntans and to determination of their role in the microbial homeostasis of dental plaque.

4-Aminobenzoic Acid↗

PubMed2000

[Immobilization osteoporosis and fracture in children].

This study was intended to enhance the diagnostic vigilance of immobilization osteoporosis with fracture and explore its prevention and treatment. Thirteen children with the hip disease underwent one to nine months of plaster cast after operation. A retrospective analysis was made on these 13 patients with fracture and immobilization osteoporosis. The result showed that disuse fracture occurred in fifteen places of their femora. All of these cases were cured by non-operative and drug treatment. These data suggest that for the cases of immobilization osteoporosis it is important to prevent fracture by means of early diagnosis, proper drugs, early function exercise, appropriately shorter period of fixation and the avoidance of trauma.

Child↗

PubMed2000

[Studies on the correlation between production of L-malic acid and some cytosolic enzymes in the L-malic acid producing strain Aspergillus sp. N1-14].

The cytosol enzymatic study in the case of high L-malic acid(LMA) production of Aspergillus sp. N1-14' was reported. The activities of 4 kind enzymes that catalyse the CO2 fixation reactions have been detected, which are pyruvate carboxylase(PC), phosphoenolpyruvate carboxlase (PEPC), phosphoenolpyurvate carboxykinase(PCK) and malic enzyme(ME). With the exception of ME, the linear correlation was found between activities of three carboxlases and the production rate of LMA. The activity of malate dehydrogenase(MDH) was at the level of 2-3 exponential higher than that of the other analysed enzymes, while the activity of succinate dehydrogenase(SDH) was much lower, and as a discrepancy, SDH was in a positive correlation to the content of LMA in fermenting slurry(r = 0.9252). It is shown that the accumulated LMA acted as an activator of SDH. Through dynamic study, it is found that, in contrast with the slow and even increase of biomass, the content of cytosol protein(Cp) sharply fluctuated mainly due to the changes of aeration conditions. The data of the linear correlation coefficients(r) of activities of cytosol enzymes to Cp(PC r = 0.9563, PEPC r = 0.7688, PCK r = 0.7300, MDH r = 0.3920, SDH r = -0.2086) exhibited an inner law of protein synthesis. Experiment of increasing the amount of spore inoculum resulted in increase of LMA and decrease of SA. After fermenting 120 h in a 5 L stirred fermentor, with 3-fold of original spore inoculum 105.88 g/L of LMA was achieved, the overall productivity was 0.883 g/(L.h), the converting rate of glucose to LMA was 78.43%. This result supports the exist of a inner law of protein synthesis in the early period of LMA fermentation by Aspergillus sp. N1-14'.

Aspergillus↗

PubMed2000

[Conditions of enzyme production and properties of alkaline lipase by Streptomyces Z94-2].

An alkaline lipase producing strain streptomyces Z94-2 was selected from 152 lipase producer, The optimal medium composition for the producing lipase is (g/L): soybean meal 30, urea 10, dextrin 10, KH2PO4 0.5, NaCl 1, MgSO4.7H2O 0.5, AEO9 (nonionic surfactant) 1. The optimal conditions for lipase producing are initial pH 9.5-10.0, shaken at 26 degrees C, for 48 h, a maximal lipase activity of reached 596 (u/mL). The optimal activity at pH 9.8 and at 37 degrees C, respectively. The lipase was stable at pH 8.6-10.2 and below 60 degrees C, and the lipase was highly activated by 0.14 mol/L CaCl2.

Calcium Chloride↗

PubMed2000

[Production of monoclonal antibodies to broad bean wilt virus and application in virus detection].

Six hybridoma cell lines secretion monoclonal antibodies(MAbs) against broad bean wilt virus(BBWV) were produced by fusing mouse myeloma cells(SP 2/0) with spleen cells from BAL B/c immunized by the BBWV particles. The hybridoma cell lines secreted MAbs stably after cultured in vitro for 3 months or stored in liquid nitrogen and then revived for several times. The titres of ascitic fluids of six MAbs ranged from 1:256,000 to 1:640,000 when measured by indirect ELISA. In agarose gel immunodiffusion test, it showed that the six MAbs represented the same isotype of murine antibodies, IgG1. Six MAbs could detect 4 tested BBWV isolates, but didn't crossreact with other 5 plant viruses. The result of Western blot showed that all the six MAbs can react with the 44.7 kD large coat protein subunit of BBWV. This is the first report of production of MAbs against BBWV.

Animals↗

PubMed2000

[Continuous ethanol fermentation using tapioca starch by immobilized yeast cell without carrier].

A widespread interest has been noted in continuous power ethanol fermentation utilizing systems with immobilized yeast cell through self-flocculating. We studied continuous ethanol fermentation by a naturally flocculent strain of Schizosaccharomyces pombe and the performance of two-stage continuous ethanol fermentation system using suspended-bioreactors(total effective volume 1.5 L) has been established: the high biomass levels achieved allow efficient ethanol conversion(72.7 g/L, average), residual glucose(3.74 g/L) and high productivity(9.7 g/L.h) for 150 g/L glucose concentration in feed(tapioca syrup) with average 90% total conversion of substrate. The system was run steadily during a month research.

Bioreactors↗

PubMed2000

[Detection of cucumber mosaic virus subgroup II isolate from tobacco plants in Yunnan province].

One of the spherical virus(designated as CMV-YNb) was isolated form the tobacco plants in Yunnan province. SDS-PAGE showed that this virus contained one polypeptide with molecular weights of 55 kD. The polypeptide was submitted to automated Edman degradation, and found the 10 amino acid sequence of the N-terminus of 55 kD protein shares 100% identity with amino acid sequence of coat protein of CMV-Q, which is belong to CMV Subgroup II. Western blot analysis also showed that this 55 kD protein was serological related to CMV-Q. A 0.9 kb cDNA fragment was amplified by RT-PCR from the RNA template of CMV-YNb with the QCf/QCr primer pair, which was designed according to the CP gene sequence of CMV-Q. The cDNA fragment was then cloned and sequenced. The fragment comprises 865 bp (EMBL accession number: AJ242585), including a 197 bp of 5' intergenic region, 657 bp of CP gene encoding 158 amino acids and a 11 bp of 3' partial non-coding region. Comparison of the nucleotide and amino acid sequences of CMV-YNb CP gene with that of CMV strains belonging to Subgroup II, and that of CMV strains belonging to subgroup I showed 97%-98% and 96%-99%, 75%-76% and 78%-79% identities, respectively. With these data, we made a conclusion that the CMV-YNb is an isolate of CMV Subgroup II.

Amino Acid Sequence↗