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Biomedical subjects

J Sun

Publications and source records attributed to J Sun.

At least 181 records · Page 10Linked to original sources
PubMed2001

[Investigation on method speliality in identifying Fructus Crataegi with vitexin rhamnoside].

The methanol extract of Fructus Crataegi was purified on macro-reticular resins(model DM130)-polyamide column. Vitexin rhamnoside(I) was identified from Fructus Crataegi by TLC on polyamide layer sheets. The false and the confused species of Fructus Crataegi and some traditional Chinese herbal medicines which contain vitexin were studied by the same method. The results indicated that compound I was special constitute of Fructus Crataegi and the identification method of Fructus Crataegi with I was special.

Apigenin↗
PubMed2001

[Determination of shrinkage and bending strength of GI-II infiltrated ceramic].

OBJECTIVE: To determine the shrinkage and strength of GI-II Infiltrated Ceramic for providing scientific basis of its clinical use. METHODS: The adobes by slip-casting alumina powder of GI-II Infiltrated Ceramic were sintered at 1125 degrees C for 2 hours. The sintered alumina bodies were then divided into two groups and infiltrated by melt glass at 1125 degrees C and 1100 degrees C respectively for 6 hours. The length of the infiltrated ceramic specimens before and after fabrication was determined to calculate shrinkage. Their strength values were obtained by 3-point bending test. RESULTS: The infiltrated ceramic infiltrated at 1125 degrees C was 0.289 +/- 0.155% in shrinkage, 367.7 +/- 76.1 MPa in strength, and 4.79 in Weibull modulus; that infiltrated at 1100 degrees C was 0.253 +/- 0.043%, 377.5 +/- 64.4 MPa, and 5.52, respectively. There was no statistically significant difference between those two groups. But their strength values were statistically high, compared with 300 MPa. CONCLUSION: The shrinkage of GI-II Infiltrated Ceramic could be compensated by brushing spacer on dies and expansion of die stone. Its strength satisfied the requirement for clinical use of all-ceramic bridge materials. This kind of high-strength and low-shrinkage ceramic could be used for fabricating all ceramic crown and bridge core.

Aluminum Oxide↗
PubMed2001

[Application of wide-bore capillary gas chromatography in the synthesis of special esters of methacrylic acid].

A simple, rapid and accurate method for separating and analysing components in the synthesis of special esters of methacrylic acid by gas chromatography is reported. An SE-54 wide-bore capillary column of 50 m x 0.53 mm i.d. x 0.6 microns was used. The esters include dimethylaminoethyl methacrylate(DMAM), n-butyl methacrylate(BMA) and ethylene glycol dimethacrylate(EGDMA). Crude materials such as methyl methacrylate(MMA) and N, N-dimethyl ethanol amine (DMEA) were also analysed. The recoveries were 99.71%-102.89%, and the RSDs of the main components were below 0.1%. The method can be used to control the production of the esters.

English Abstract↗
PubMed2001

[Production and some properties of a beta-glucanase from Trichoderma sp. GXC].

The factors affecting Trichoderma sp. GXC for beta-glucanase (1,3-1,4-beta-D-glucan 4-glucanohydrolase, EC 3.2.1.73) production have been investigated, the optimal conditions were that carbon and nitrogen sources were bran and ammonium sulfate, respectively, initial pH 4.0-5.0, shaken at 30 degrees C for 44 h. beta-glucanase was purified to electrophoretic homogeneity by using ammonium sulfate precipitation, Sephadex G-100 and DEAE-Sephadex A-50 chromatography. It's molecular weight was 35 kD by SDS-PAGE, and the enzyme functioned optimally at pH6.0 and 50 degrees C, respectively. In addition, the enzyme was stable at pH 4.0-5.0 and below 40 degrees C. The beta-glucanase activity was significantly inhibited by Fe3+ and stimulated by Co2+, respectively.

Enzyme Stability↗
PubMed2001

[Investigation and evaluation on the harmfulness of partial vibration and the contact vibration time].

The harmfulness from partial vibration with extended contact vibration time was studied by investigating into the symptoms and signs of workers with local vibration disease in Taiyuan Iron & Steel Company. The sense of hand, the function of nerve ending and the microcirculation of fingernail wrinkles of 321 workers working on local vibration operations were examined and observed. The indexes examined are worse with the increase of contact time and are better in low contact group. A positive correlation between the abnormal of microcirculation, the pain and numbness of hand was observed. It is concluded that the degree of harmfulness on hands and upper limbs of whom working on local vibration operation is related to the time of contact vibration. The function of nerve ending and the ending circulation were injured at the same time.

Adult↗
PubMed2001

[Effect of NaFeEDTA fortified soy sauce on iron deficiency anemia in students].

NaFeEDTA fortified soy sauce was given to 300 students with iron deficiency anemia (IDA) for 3 months. The subjects were divided into three groups: control group, low iron supplemented group (Fe 5 mg/d) and high iron supplemented group (Fe 20 mg/d). Hemoglobin (Hb), serum iron, serum ferrtin, erythrocyte protoporphyrin, total iron binding capacity and serum transferrin were evaluated before and after the study. The results showed that Hb, serum iron, ferrtin and transferrin of the intervention groups had improved and erythrocyte protoporphyrin, total iron binding capacity decreased. There were no differences between the two intervention groups after the trial. The parameters of both intervention groups were much better than those of the control group. The results suggested that NaFeEDTA fortified soy sauce had positive influence on IDA.

Adolescent↗
PubMed2001

[Mutation of beta 3-adrenergic-receptor gene and the response to dietary intervention in obese children].

In order to study the relationship between mutation of beta 3-adrenergic-receptor gene and the response to dietary intervention in obese children, 47 obese children were randomly separated into two groups. One was dietary intervention group(36 subjects); the other was control group(11 subjects). The subjects were investigated by dietary survey and anthropometry before and after dietary intervention carried out for 3 months. The mutation of beta 3-adrenergic receptor gene resulting from the replacement of tryptophan by arginine at position 64(Trp64Arg) in encoding amino acid residues was detected by using a polymerase chain reaction-restriction fragment length polymorphisms. The results showed that dietary fat was higher (40.7% of energy from fat) in the obese children. After dietary intervention, the increase of weight(kg) and BMI(kg/m2) were significantly lower in the obese children without mutation than in control group(P < 0.05), but the changes of weight and BMI in the obese children with mutations were similar to those of control group. It was concluded that the Trp64Arg mutation of beta 3-adrenergic receptor gene might be one of the reasons why the effect of dietary intervention was poor in some obese children.

Child↗
PubMed2001

[The effect of frozen storage for amniotic membrane ultrastructure].

OBJECTIVE: To observe the effect of frozen storage for amniotic membrane ultrastructure, and provide the experimental evidence for clinical use. METHODS: The amniotic membranes of fresh-obtained and -80 degrees C frozen storage 30 d, 60 d, 90 d and 180 d were examined with transmission electron microscope, and the ultrastructural changes were observed. RESULTS: The epithelium in the fresh-obtained amniotic membrane was observed as intact structure, abundant organelles in cytoplasm and intercellular contact with desmosome. A great quantity of collagen micro-fibrils were found in the stroma, and the light and shade striation were observed in the collagen micro-fibrils of fresh-obtained amniotic membrane. The epithelium degenerated and died gradually as the increase of frozen storage time. At the frozen storage of 90 days, the epithelial chromatin dissolved, organelles degenerated and mitochondrion vacuolated. At the frozen storage of 30 days and 60 days, the pattern of collagen micro-fibrils in stoma was similar to that in fresh-obtained amniotic membrane; At the frozen storage of 90 days, some of collagen micro-fibrils in stoma showed intumescence. At the frozen storage of 180 days, the number of collagen micro-fibrils in stoma decreased, and some of them showed intumescence and dissolvent. CONCLUSION: Frozen storage can result in amniotic membrane epithelium death and collagen micro-fibrils intumescence and dissolvent.

Adult↗
PubMed2001

[Study of bone mineral density measuring system with quantitative CT].

This paper introduces a kind of bone mineral density(BMD) measuring system with quantitative CT(QCT). This system includes a self-made solid calibration phantom for BMD and the measuring software. The results of the tests have showed that this system is reliable, cheap and ease of use for BMD measurement.

Absorptiometry, Photon↗
PubMed2001

[Bonding and mechanical interlocking of three kinds of luting cements in retention of complete metal crowns].

OBJECTIVE: To evaluate the effects of bonding and mechanical interlocking of three kinds of luting cements in the retention of complete metal crowns. METHODS: Zinc phosphate cement (ZP), glass ionomer cement (GI) and polycarboxylate cement (PC) are in common use for clinical treatment. In this study, these cements were selected to bond the complete crowns to molars in vitro. The retention capacities of the complete crowns were tested and compared. And apart from mechanical interlocking, the effect of bonding was tested. On this basis the interlocking capacity of the cement was calculated. RESULTS: 1. The retention capacities of complete metal crowns from the highest to least were: GI > ZP > PC. 2. The proportions of mechanical interlocking of ZP, GI and PC in the retention of complete metal crowns were 62.6%, 48.3% and 20.1% and the ratios of bonding of ZP, GI and PC were 37.4%, 51.7% and 79.9%, respectively. CONCLUSION: The effects varied with different cements in the retention of complete metal crowns because of the discrepancy in bonding and mechanical interlocking properties. Mechanical interlocking plays a prominent role when ZP or GI is used, and the role of bonding is apparent in PC.

Adhesives↗
PubMed2001

[The value of three-dimensional helical CT imaging in the diagnosis of maxillofacial fractures].

OBJECTIVE: To assess the diagnostic value of three-dimensional (3D) helical CT imaging in the cases of maxillofacial fractures. METHODS: 25 trauma patients were examined with thin-slice CT scan and 3D reconstruction. RESULTS: Three-dimensional images reconstructed from helical CT clearly and stereoscopically demonstrated the location, shape and extension of maxillofacial fractures. CONCLUSION: 3D helical CT imaging can provide valuable information in demonstrating space relationships of maxillofacial fractures.

Adolescent↗
PubMed2001

[Surgery of the skull base assisted by sinus endoscope].

OBJECTIVE: To explore the feasibility and clinical value of the endoscopic operations around the skull base. METHODS: A retrospective study was made of 44 cases treated by endoscopic operations. Twenty-five cases underwent intranasal endoscopic operations. RESULTS: Forty of 44 cases were cured by one-stage surgery. One case of cartridge foreign body clamped in clivus was not successfully removed; only window operation and puncture biopsy were done in another case of pituitary adenoma; high cranial pressure has not been completely reduced after operation in the third case with relapsing craniopharyngioma a companied with obstructive hydrocephalus. One case of sphenoidal malignant adenoma involving saddle based and extended laterally was partly resected. Complications were follows: cerebrospinal fluid rhinorrhea in 2 cases, diabetes insipidus in 1 case, all of them were cured by conservative treatment; nasal septum perforation in 1 case, without any treatment. CONCLUSIONS: The endoscopic skull base surgery by intranasal approach is feasibility. Intranasal approach has direct path, slight wound and no wound in face. Combined with operation microscope, sinus endoscope can make up for its limits.

Endoscopy↗
PubMed2001

[Ultrastructure of surfactant-like multilamellar bodies in the human nose].

OBJECTIVE: To study the distribution of the surfactant-like multilamellar bodies in the human nose. METHODS: Fourteen specimens obtained from the inferior turbinate, middle turbinate, uncinate process and maxillary sinus were examined under the electron microscope. RESULTS: The surfactant-like multilamellar bodies were identified in the epithelium on the lateral wall and maxillary sinus. CONCLUSION: The existence of surfactant-like multilamellar bodies in the human lateral nasal wall and maxillary sinus were confirmed. It is necessary to have further study for its effect in the nose both physiologically and pharmacologically.

Adolescent↗
PubMed2001

[Observation of nasal mucosal cilia ultrastructure of Kartagener's syndrome].

OBJECTIVE: To report the ultrastructure of nasal mucosal cilia of Kartagener's syndrome and the operative results of 2 cases. METHODS: Both two cases were underwent endoscopic sinus surgery. Transmission and scanning electron microscopic examinations of nasal mucosa for case 1 were performed. RESULTS: All 2 cases presented situs inversus, chronic paranasal sinusitis and bronchiectasis. The electron microscopic examination showed that the shape of nasal cilia and "9 + 2" structure were normal, but the lack of inner dynein arm of cilia and confused arrangement of central pair of microtubules were confirmed. The recurrent of nasal polyps after 1-year follow-up was observed in case 1. CONCLUSIONS: The disturbance of mucociliary clearance due to congenital ciliary structure defect might be the cause of chronic sinusitis and polyps, which might be one of reasons for poor prognosis after operation and we should pay more close attention.

Adolescent↗
PubMed2001

[Intact-bridge tympanomastoidectomy procedure: a reasonable option in the surgery of chronic otitis media and mastoiditis with cholesteatoma and/or granulation tissue].

OBJECTIVE: To study and evaluate a surgical option for the treatment of otitis media and mastoiditis with cholesteatoma and/or granulation tissue. METHODS: The procedure is called intact-bridge tympanomastoidectomy (IBM). There are some modifications for the treatment of patients suffered from chronic otitis media and mastoiditis with cholesteatoma and/or granulation tissue. The features of IBM include: 1. the aditus, mastoid and attic opened and the intractable pathological tissues eradicated thoroughly. 2. the posterior tympanal space opened through the facial recess if necessary. 3. a widened middle ear space by lowering bony bridge established. 4. the adults blocked. 5. immediate or staging tympanoplasties conducted according to the conditions of mucosa in the tympanum. RESULTS: The modified IBM procedure was performed on 62 ears from 61 cases. The follow-up has been 12-38 months and more than two years in 51 ears. The dry ear was obtained within 5-13 weeks with an average of 6 weeks. In 24.2% of ears the air-bone gap(ABG) was 20dB HL or less and within 21-30 dB HL in 41.9% of ears, the ABG over 31 dB HL was 16.1%. CONCLUSION: Our results indicate that IBM procedure fulfills the desired purposes of both open- and close-cavity techniques, the thorough eradication of diseased tissue allow to get a dry ear and restoration of hearing. IBM, therefore, is a reasonable choice for the surgery of otitis media and mastoiditis with cholesteatoma and/or granulation tissue.

Adolescent↗
PubMed2001

[Glutamate induced modulation of free Ca2+ in isolated inner hair cells of the guinea pig cochlea].

OBJECTIVE: To investigate the modulation effect of glutamate (Glu) on intracellular free Ca2+ concentration([Ca2+]i) of inner hair cell (IHC). METHODS: Using the laser scanning confocal microscope (LSCM), the exogenous Glu-induced changes in [Ca2+]i of isolated 10 IHCs and 10 OHCs of guinea pig cochlea were observed with fluo-3, a fluorescent probe for [Ca2+]i. RESULTS: The IHCs were identified by their unique flask shape with a distinct neck and spherical base and a large spherical nucleus. In most cases, normal cell shapes could be maintained about two hours after isolation. The images of [Ca2+]i from LSCM were similar to those from inverted microscopy. Fluorescence of Fluo-3 distributed in the isolated IHCs with brighter staining in the nucleus. In the presence of low concentration of Glu (3.85 mumol/L), there was an increase of [Ca2+]i in IHCs, whereas no change in OHCs was found. Of the 10 IHCs, increases of [Ca2+]i were observed in 9 and no change in 1. Of the 10 OHCs, 7 showed no [Ca2+]i change and only 3 showed minor reduction of [Ca2+]i. An increase of the Glu concentration (21.88 mumol/L) induced a corresponding increase of [Ca2+]i in IHCs, but eventually resulted in a gradual decrease of [Ca2+]i with a distortion of the normal shape, which indicated that the IHCs were degenerated and swelling. CONCLUSION: These results suggested that exogenous Glu is capable of modulating [Ca2+]i of IHC and may be act on autoreceptor in a positive feedback manner. Excessive Glu induced the accumulation of IHC [Ca2+]i which finally resulted in the degeneration and edema of IHC and the reduction of IHC [Ca2+]i.

Animals↗