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Biomedical subjects

Song Chen

Publications and source records attributed to Song Chen.

27 records · Page 2Linked to original sources
PubMed2004

[A study on the center height of clinical crowns for the people with normal occlusion in Chengdu area].

OBJECTIVE: The purpose of this study was to investigate the center height of clinical crowns and the difference among individuals, together with the regularity of the Spee curve in mandible and compensating curve in maxilla for the people with normal occlusion in Chengdu area. METHODS: The data were derived from systematically collected people with normal occlusion in Chengdu area, including 36 males and 39 females (ranged from 18 to 35 years). The values of center height of clinical crowns, the depths of Spee curve and curve formed by the center of clinical crowns in mandible were obtained by measurement. Afterwards, the distribution of the center height of clinical crowns was analyzed, as well as the depth of curve formed by the center of clinical crowns in mandible and its correlation with depth of Spee. RESULTS: (1) The distribution of the center height of clinical crowns accord with normal distribution and the standard deviation was minor(< 0.5 mm); (2) There was no statistical difference between male and female for the center height of clinical crowns; (3) The depth of curve formed by the center of clinical crowns in mandible and the depths of Spee curve showed highly correlation (gamma = 0.986, P < 0.0001). CONCLUSION: (1) The difference of the center height in clinical crowns among individuals with normal occlusion in Chengdu area was minor; (2) There was no significant difference on the center height in clinical crowns between male and female; (3) Provide a recommended bracket placement chart suitable for people of Chengdu area in clinical practice; (4) The brackets of the pre-adjusted appliance should be placed in the center of clinical crowns, despite some adjustment are needed in some special circumstances.

Adolescent↗
PubMed2004

[Semen analysis of DNA fluorescence detection and two other routine analyzing methods].

OBJECTIVE: To compare semen analysis system of computer-aided sperm analysis (CASA) dyeing with DNA fluorescence (simplified as fluorescence CASA) with two other routine semen analyzing methods. METHODS: Twenty-two male infertile patients were selected at random as research subjects, and semen analysis was performed with fluorescence CASA, grey CASA, and microscopic analysis. RESULTS: Fluorescence CASA could distinguish sperm from non-sperm granules, as well as living from dead sperm. Compared with the sperm density detected by fluorescence CASA, the disparities of sperm densities detected by microscopic analysis and grey CASA were (9.23 +/- 8.01) x 10(6)/ml and (10.27 +/- 6.22) x 10(6)/ml, and the disparity rates of sperm density were 49.06% +/- 49.87% and 43.39% +/- 25.56% respectively. CONCLUSION: Fluorescence CASA was more conformable to the requirements of latest WHO laboratory manual for the examination of human semen, and worth recommending for the clinical analysis of semen features, especially sperm density.

Adult↗
PubMed2004

[Expression of transforming growth factor alpha, tumor necrosis factor alpha, and vascular endothelial growth factor of human pheochromocytoma tissues].

OBJECTIVE: To compare the expressions of transforming growth factor alpha (TGFalpha), tumor necrosis factor alpha (TNFalpha), and vascular endothelial growth factor (VEGF) between pheochromocytoma (PHEO) tissues and normal adrenal medulla tissues. METHODS: The mRNA expressions of TGFalpha, TNFalpha, and VEGF detected by RT-PCR, were compared between 22 PHEO tissues and 18 normal adrenal medulla tissues (according with the principle of medical ethnics). Immunohistochemistry staining was performed on 27 PHEO tissues and 14 normal adrenal medulla tissues. The comparisons of the protein expression of TGFalpha, TNFalpha, and VEGF were analyzed in both of PHEO tissues and normal adrenal medulla tissues. RESULTS: Compared with normal adrenal medulla tissues, the expressions of TGFalpha and TNFalpha mRNA and protein were higher in PHEO tissues, and VEGF145 mRNA expression was also higher in PHEO tissues, while there was no significant difference of the mRNA expression of VEGF121 and VEGF165 between these two tissues. Positive staining rates for VEGF of endothelial cells and tumor cells were higher in PHEO tissues than in normal adrenal medulla tissues. Expressions of the TGFalpha, TNFalpha, and VEGF protein were higher in extra-adrenal PHEO than in adrenal PHEO. The TNFalpha immunohistochemistry staining rate was higher in the malignant or multiple PHEO than in the benign or single PHEO. CONCLUSIONS: The mRNA and protein expressions of TGFalpha, TNFalpha, and VEGF are higher in PHEO tissues than those in normal adrenal medulla tissues. Expressions of these cytokines vary in PHEO with different characteristic.

Adrenal Gland Neoplasms↗
PubMed2002

Genetic evolution of structural region of hepatitis C virus in primary infection.

AIM: To investigate the dynamics of hepatitis C virus (HCV) variability through putative envelope genes during primary infection and the mechanism of viral genetic evolution in infected hosts. METHODS: Serial serum samples prospectively collected for 12 to 34 months from a cohort of acutely HCV-infected individuals were obtained, and a 1-kb fragment spanning E1 and the 5' half of E2, including Thirty-three cloned cDNAs representing each specimen were assessed by a method that combined a single-stranded conformational polymorphism (SSCP) and heteroduplex analysis (HDA) method to determine the number of clonotypes hypervariable region, was amplified by reverse transcriptase PCR and cloned. Nonsynonymous mutations per nonsynonymous site (dn), synonymous mutations per synonymous site (ds), dn/ds ratio and genetic distances within each sample were evaluated for intrahost evolutionary analysis. RESULTS: Quasispecies complexity and sequence diversity were lower in early samples and a further increase after seroconversion, although ds value in the envelope genes was higher than dn value during primary infection. The trend, pronounced in most of samples, toward lower ds values in the E1 than in the 5' portion of E2. Quasispecies complexity was higher and E2 dn/ds ratio was a trend toward higher value in later samples during persistent viremia. We also found individual features of HCV genetic evolution in different subjects who were infected with different HCV genotypes. CONCLUSION: Mutations of actively replicating virus arise stochastically with certain functional constaints. A complexity quasispecies exerted by a combination of either neutral evolution or selective forces shows clear differences in individuals, and associated with HCV persistence.

Adult↗
PubMed2002

[Histological observation of the interface of oral epithelium and titanium implant with titanium dioxide on the surface]

OBJECTIVE: To investigate the healing process at the interface between oral epithelium and a titanium implant with titanium dioxide on the surface and whether a good epithelial barrier could be formed. METHODS: Titanium implants with titanium dioxide on the surface were placed in the mandibular alveolar area of Beagle dogs after their premolars had been removed three months previous. On the 15th day, second month and loading second month after implantation specimens were taken and examined after HE staining as well as by transmission electron microscopy. RESULTS: Fifteen days after implantation the epithelial collar was formed, junctional epithelium actively regenerated and attachment to the matrix on the surface of the implant occurred by hemidesmosomes. Two months after implantation junctional epithelium was increasing, showing three to four layers consistent with each other. Junctional epithelium appeared to be generated when stimulated by inflammation and shaped into epithelium rete pegs after loading for two months. CONCLUSION: Oral junctional epithelium can attach very well to titanium implants with titanium dioxide on the surface which also provides a biological barrier.

Journal Article↗
PubMed2002

[Application of confocal scanning laser Doppler retinal flowmetry in the measurement of fundus blood flow parameters after retinal detachment surgery].

OBJECTIVE: To discuss the influence of retinal detachment (RD) surgery on the blood flow of retina and optic nerve head. METHODS: Heidelberg Retina Flowmeter (HRF) was used to measure the blood flow of retina and optic nerve head in 62 eyes of 62 patients with postoperative rhegmatogenous RD surgery, including 34 eyes having undertaken vitreoretinal (VR) surgery and 28 eyes, scleral buckling (SB) surgery. Operative methods included scleral encircling procedure, cryotherapy, lensectomy, vitrectomy, perfluorodeclin liquid application, endolaser and C(2)F(6) gas or silicone oil tamponade. RESULTS: The blood flow volume (VOL), blood flow velocity (FLW) and the erythrocyte flow velocity (VEL) of fundus in the postoperative RD eyes were reduced in the comparison with those of the fellow control eyes. The VEL of temporal and nasal papillary disk rim had significant differences (P < 0.05). The VOL, FLW and VEL of the papillary vessel, VOL and FLW of temporal and nasal papillary disk rim, VOL of temporal and nasal juxtapapillary retina in the operative eyes were lower than those of the fellow eyes (P < 0.01). In the comparison between the eyes having undertaken VR surgery and the eyes undertaken SB surgery, the VOL, FLW and VEL of VR surgery were reduced more than those of SB surgery. The VEL of temporal and nasal papillary disk rim and nasal juxtapapillary retina and FLW of temporal juxtapapillary retina had significant differences (P < 0.05). VOL, FLW and VEL of silicone oil tamponade eyes were reduced more than those in the operative eyes without silicone oil tamponade. VOL of nasal papillary disk rim and juxtapapillary retina had significant differences (P < 0.05). VOL and VEL of temporal papillary disk rim, VOL of temporal juxtapapillary retina had very significant differences (P < 0.01). CONCLUSIONS: VR surgery and SB surgery of RD influence papillary and retinal VOL, FLW, VEL. The influence of VR surgery on the fundus blood flow is more significant than that of SB surgery. The silicone oil tamponade also influences the VOL and VEL of the fundus.

Adolescent↗
PubMed2002

[Pre-surgical orthodontic treatment of skeletal class II patients with gingival smile corrected by anterior maxillary segmental osteotomy].

OBJECTIVE: To discuss the pre-surgical orthodontic treatment of skeletal class II patients with gingiva smile corrected by AMSO. METHODS: We analyzed the clinical features of 20 skeletal class II patients treated by AMSO combined with Orthodontic treatment and evaluated the effects of AMSO by means of cephalometric analysis. RESULTS: After the AMSO treatment, ANB angle, the height of anterior maxilla, the protrusion of the upper anterior teeth, and the of A point had reduced significantly (P < 0.05). After AMSO, the appearance of patients had been improved markedly. CONCLUSIONS: AMSO can correct the protrusion of the maxilla and gingival smie efficiently. The anchorage of molars should be controlled carefully. The anterior part of the upper arch should be expended orthodontically to make arch relationship. Extract the upper bicuspid half a year before the surgery was recommended. When necessary, genioplasty could be performed.

Adult↗
PubMed2002

[Genetic variation characteristics of the envelope region of hepatitis C virus in the patients with chronic hepatitis].

OBJECTIVE: To study the association of the envelope region variation of hepatitis C virus (HCV) with the chronicity of HCV infection. METHODS: Acute phase plasma samples from three injection drug users who acquired HCV infection during six month follow-up and three patients with chronic hepatitis C were obtained. A 573 bp fragment containing the 5' half of E1 and 3' half of E2 were amplified by nested reverse transcription polymerase chain reaction (RT-PCR). For each cloned cDNAs were examined by a method that combined heteroduplex (HD) analysis and a single-stranded conformational polymorphism (SSCP) assay to assess quasispecies complexity and optimize selection of clones with unique gel shift patterns for sequencing. The ratio of nonsynonymous to synonymous substitution (dN/dS) within each sample was evaluated as an indicator of relative selective pressure. Amino acid sequences were analyzed for signature patterns and glycosylation signals. RESULTS: Quasispecies complexity and E2 dN/dS ratio were higher in those with chronic hepatitis, in whom a trend toward more numbers of nonsynonymous mutations was detected at the E2. 1.02% (1.33/130) and 8.46% (11/130) amino acids within the E2 region mutated in chronic hepatitis and acute hepatitis, whereas within the E1 region 2.74% and 1.09% amino acids replaced among chronic and acute hepatitis respectively. Some consistent amino acids were detected, although the hypervariable region 1 (HVR1) had a higher variability in subjects with chronic infection. CONCLUSIONS: HCV persistence is associated with a complex quasispecies and host immune selection to HVR1.

Genetic Variation↗