Biomedical subjects

Y Zhao

Publications and source records attributed to Y Zhao.

At least 253 records · Page 14Linked to original sources

PubMed2001

[Effect of dietary protein on the function and morphology of diaphragm in rats with experimental emphysema].

The effects of dietary protein on the function and morphology of diaphragm of rats with emphysema were observed in 50 SD rats, 10 rats in each group. The emphysema in groups E(emphysema control), HP(emphysema with high protein diet) and LP(emphysema with low protein diet) was induced by intra-tracheal instillation of elastase (750 U/kg BW). The control rat (C1, C2) were instilled with normal saline. After 6 weeks of experiment, the total lung volume and the average area of alveolus was significantly increased in the group E compared with group C1 (P < 0.05) and the number of alveolus per unit area was also reduced obviously (P < 0.05). The average contractile force of diaphragm at a stimulus rate of 20 Hz expressed as a ratio of the maximal contractile force (F20/Fmax) was increased significantly in group E compared with group C (P < 0.01). The cross-sectional area of slow-twitch fibers increased significantly in group E. After 10 weeks of oral supplementation with 24% casein(HP) or 8% casein (LP) to the rats with emphysema, the contractility of the diaphragm in group LP was lower than that in the control group and the HP group. It was concluded that high protein diet might be beneficial to maintain the function of diaphragm in patients with emphysema.

Animals↗

PubMed2001

[Effect of decreased bite force on the temporal and spatial expression of type I collagen mRNA in rat molar periodontal ligament].

OBJECTIVE: The aim of this study was to observe the effect of decreased bite force on type I collagen mRNA in periodontal ligament (PDL) and probe into the molecular mechanism of the change in type I collagen mRNA. METHODS: Animal models were established by extracting left maxillary molars of rats. In situ hybridization was applied. RESULTS: The results showed that under decreased bite force, the expression level of type I collagen mRNA decreased at the sixth hour (49.7 +/- 11.1) (P < 0.05), reached the nadir on the second day (23.7 +/- 8.6), began to get over on the third day (43.1 +/- 10.3), and reached a relatively high level at the second week(56.3 +/- 9.8), but it was still lower than that of the normal bite force group (91.4 +/- 16.0)(P < 0.05); the expression of type I collagen mRNA near the cementum was higher than that near the alveolar bone. CONCLUSION: These results indicate that the expression level of type I collagen mRNA is closely related to bite force.

Animals↗

PubMed2001

[Effects of laser welding on ceramic fused to metal].

OBJECTIVE: This study was aimed to investigate the bonding effect of laser welding on ceramic fused to metal. METHODS: Ten laser welded CW-PA ceramo-alloy rods were fused with porcelain at fusion zone. The porcelain-metal bond strength was measured with pull-through test. SEM examination and EDAX analysis were performed. Ten non-welded CW-PA ceramo-alloy pull-rod plates were used as comparison. RESULTS: The results showed that the bond strength of laser welded sample was 41.32 +/- 6.69 MPa, approaching to 45.71 +/- 9.98 MPa of the non-welded sample (P > 0.05). The microscope displayed the interface compacted union of the two phase boundary. There was no change in the elements and their ratio at the fusion zone. CONCLUSION: These results indicate that laser welding does not affect ceramic fused to metal.

Dental Porcelain↗

PubMed2001

[Effect of increased and decreased bite force on morphology of periodontal tissues].

OBJECTIVE: The aim of this study was to observe the effect of bite force on morphology of periodontal tissues. METHODS: Animal models were induced by extracting the left maxillary molars; the left mandibular molars served as decreased bite force models; the right mandibular molars served as increased bite force models. The dynamic changes of widths of periodontal ligament and cementum were measured. RESULTS: In decreased bite force group, there were significant morphologic changes of periodontal tissues after 1 week. In increased bite force group, there was no significant change. Ligament widths were significantly different after 2, 3 weeks respectively in those two groups, compared with that in control group (P < 0.05). There were significant differences between proximal alveolar wall and distal alveolar wall in width (P < 0.05). CONCLUSION: The histological morphology is closely related to the mechanical condition. Physiological bite force is necessary for periodontal ligament to maintain its physiological structure.

Animals↗

PubMed2001

[Experimental studies of antitumor effect of artesunate on liver cancer].

OBJECTIVE: To observe the inhibiting effect of Artesunate on liver cancer in vitro and in vivo. METHOD: The mice bearing H22 solid and ascitic liver tumor were applied in vivo experiments. Microculture tetrazolium assay and colony-forming unit assay were applied to test the cytotoxicity to human hepatocarcinoma SMMC-7721 cell line in vitro. RESULT: The growth of solid tumor were obviously inhibited by Artesunate at the dose of 300 mg.kg-1.d-1 ig for 7 days. The tumor inhibiting rates of Artesunate were 49.1%, 48.7%, 46.6% in 3 experiments respectively. After administration of Artesunate, the survival rate of the mice bearing H22 ascitic liver tumor were increased to 45%. Compared with the control groups, the difference was statistically significant (P < 0.01). In additional, Artesunate can synergize the antitumor activity of 5-fluorouracil. Artesunate showed evident cytotoxicity to human hepatocarcinoma SMMC-7721 cells, the IC50 of Artesunate being 2.07 micrograms.ml-1 in MTT experiment and 2.48 micrograms.ml-1 in colony-forming unit experiment. CONCLUSION: Artesunate has marked antitumor activity in vitro and in vivo.

Animals↗

PubMed2001

Preliminary study of three-tone paradigm auditory P300 on aging dementia.

OBJECTIVE: To explore the changes of three-tone paradigm P300 and observe the improvement of the diagnostic sensitivity of P300 in aging dementia. METHODS: Thirty-four patients of aging dementia underwent traditional P300 (2t-P300) and three-tone paradigm auditory P300 (3t-P300). The results of these two methods were compared. RESULTS: Abnormal P300 was found in 18 of 34 dementia cases (52.9%) by 2t-P300, and in 26 of 30 patients who finished the 3t-P300 tests (86.7%). In 2t-P300, 9 of 24 mild cases, 7 of 8 moderate cases and 2 severe cases showed abnormal results. In 3t-P300, 20 of 24 mild cases and all 6 moderate cases showed abnormal results. Abnormal 3t-P300 was found in 13 of 16 cases which showed normal 2t-P300. Besides prolonged and bad-shaped P300, no certain response of P300 to rare non-target stimulus (r-nT) was found in 10 mild cases by 3t-P300. CONCLUSION: Three-tone paradigm auditory P300 had higher sensitivity in early diagnosis of aging dementia than traditional auditory P300. No P300 response to r-nT in 3t-P300 is an important index in early diagnosis of mild dementia.

Aged↗

PubMed2001

[Relationship between vascular endothelial growth factor expression and angiogenesis in osteosarcoma].

OBJECTIVE: To determine the relationship between angiogenesis and vascular endothelial growth factor (VEGF) expression in osteosarcoma. METHODS: The expression of VEGF was evaluated by immunohistochemical staining of tumor specimens from 33 patients with osteosarcoma. The microvessel density was assessed by immunostaining with CD34 in the most neovascularized area (hot spots). RESULTS: In osteosarcoma, the mean microvessel count of VEGF strong-expression tumors was significantly higher than that of VEGF low-expression tumors (Wilcoxon rank sum test, P < 0.05). The close correlation was found between VEGF expression and microvessel density. In contrast, no association was found between Price's grade of osteosarcoma and VEGF expression, as well as microvessel density. CONCLUSION: These observations suggest that VEGF is an important angiogenic factor in osteosarcoma.

Humans↗

PubMed2001

[Application of diapason instrumentation for treatment of unstable lumbosacral spinal stenosis].

OBJECTIVE: To observe the preliminary clinical outcome of using a new instrumentation Diapason system and to introduce the characterization and surgical technique of this new system for treatment of unstable lumbar spinal stenosis. METHODS: 16 patients with unstable spinal stenosis who were treated by decompression, posterolateral intertransverse arthrodesis and transpedicle instrumentation of Diapason system, were analyzed retrospectively. RESULTS: Lower back pain (LBP) of 16 patients were significantly alleviated after surgery (scores of LBP before operation: 47.5 +/- 0.8; scores of LBP after operation: 31.9 +/- 2.3, P < 0.001). There was no implant failure, no early or later infection and no neurological complications in 16 patients at an average of 6.2-month follow-ups. No pseudoarthrosis was observed on roentgenography. CONCLUSION: Our short-term follow-up and limited cases study showed satisfactory preliminary result of treating unstable lumbar spinal stenosis with Diapason internal fixation.

Adult↗

PubMed2001

[Relationship between alpha-ENaC gene Thr663Ala polymorphism and ischemic stroke].

OBJECTIVE: To determine the relationship between Thr663Ala polymorphism in amiloride-sensitive epithelial sodium channel alpha-subunit (alpha-ENaC) gene and ischemic stroke in Chinese population. METHODS: Two hundred and ninety-four patients with cerebral infarction and 280 controls without stroke were screened by polymerase chain reaction (PCR) and corresponding Thr663Ala polymorphism probe hybridization. RESULTS: Thr663Ala polymorphism was in agreement with Hardy-Weinberg equilibrium. Both the carriers proportion (70.75%) and the frequency (48.64%) of 663Ala allele in patients were more prevalent than that in controls (62.86% and 40.89%) (P < 0.05). The presence of at least one 663Ala allele conferred an odds ratio for stroke of 1.429 (95%CI: 1.009-2.025), and the proportion of attributable risk of population (PAR%) was 11.63%. CONCLUSION: Thr 663Ala polymorphism of alpha-ENaC gene may be a genetic risk of ischemic stroke in Chinese population.

Aged↗

PubMed2001

[Killing effect of human pulmonary adenocarcinoma cells with TK + CD/5-Fc + GCV coexpression suicide gene systems].

OBJECTIVE: To investigate the different killing effect to human pulmonary adenocarcinoma cell line cells GLC-82 with coexpressed double suicide genes compared with single gene. METHODS: Recombinant expression vectors containing CD (cytosine deaminase) and/or TK (thymidine kinase) gene under CMV promoter were constructed successfully. The vectors were transfected to GLC-82 tumor cell lines by use of lipofectamine. The clones were picked out after G418 selection. Extraneous gene integration and expression were confirmed by PCR and semi-quantitative RT-PCR. The cytotoxicity to these transgenic cells under treatment with 5-Fc and GCV were measured by MTT assays. RESULTS: Double and single suicide gene transfer were both stably expressed in GLC-82 cells. The cytotoxic effects of co-expressed TK-CD genes were superior than that of the single gene. CONCLUSION: The CD + TK/5-Fc + GCV co-expression system is more effective for killing effect of tumor cells than CD/5-Fc or TK/GCV system alone.

Cell Line, Tumor↗

PubMed2001

[Automatic detecting 400.0 nm break of galaxies spectra].

This paper presents an automatic method to detect the position of 400.0 nm break in galaxies spectra. This spectral discontinuity is due to the opacity produced by the presence of a large number of spectral lines of ionized metal. It is largely used to determine the star formation characteristics of distant field and cluster galaxies. The position of the discontinuity is an indicator of redshift. Detecting the position by hand is not possible in a sky survey with large amount of spectra data. We develop an automatic method using wavelet transform and discrete convoution. All steps are given in the paper. The program subtracts the spectral lines from a continuum using wavelet filter and determines that the spectrum is an emission line galaxy. Then the discontinuity position is obtained by convolution between a step function and the continuum, at last, the program computes the redshift z, and identifies strong emission lines using computed z. When the strong lines are identified, the position is determined. We use 3 data set to test our program. The results suffice to show that discontinuity position is very precisely measured. This method can be the first step for studying the galaxies spectra surveys.

English Abstract↗

PubMed2001

[FTIR study of transition metal 2-acrylamido-2-methyl-1-propanesulfonates].

Compounds of transition metal ion (Cu2+, Co2+, Ni2+) 2-acrylamidomethyl-2-methyl-1-propanesulfonates were studied by FTIR and X-ray powder diffraction techniques. The FTIR spectra of Co and Ni compound are similar but are different from that of Cu compound. The results of X-ray diffraction indicated that the crystal structure of Co and Ni compound are different.

Acrylamides↗

PubMed2001

Measuring population health risks using inpatient diagnoses and outpatient pharmacy data.

OBJECTIVE: To examine and evaluate models that use inpatient encounter data and outpatient pharmacy claims data to predict future health care expenditures. DATA SOURCES/STUDY DESIGN: The study group was the privately insured under-65 population in the 1997 and 1998 MEDSTAT Market Scan (R) Research Database. Pharmacy and disease profiles, created from pharmacy claims and inpatient encounter data, respectively, were used separately and in combination to predict each individual's subsequent-year health care expenditures. PRINCIPAL FINDINGS: The inpatient-diagnosis model predicts well for the low-hospitalization under-65 populations, explaining 8.4 percent of future individual total cost variation. The pharmacy-based and in patient-diagnosis models perform comparably overall, with pharmacy data better able to split off a group of truly low-cost people and inpatient diagnoses better able to find a small group with extremely high future costs. The model th at uses both kinds of data performed significantly better than either model alone, with an R2 value of 11.8 percent . CONCLUSIONS: Comprehensive pharmacy and inpatient diagnosis classification systems are each helpful for discriminating among people according to their expected costs. Properly organized and in combination these data are promising predictors of future costs.

Adolescent↗

PubMed2001

Finding future high-cost cases: comparing prior cost versus diagnosis-based methods.

OBJECTIVE: To examine the value of two kinds of patient-level dat a (cost and diagnoses) for identifying a very small subgroup of a general population with high future costs that may be mitigated with medical management. DATA SOURCES: The study used the MEDSTAT Market Scan (R) Research Database, consisting of inpatient and ambulatory health care encounter records for individuals covered by employee- sponsored benefit plans during 1997 and 1998. STUDY DESIGN: Prior cost and a diagnostic cost group (DCG) risk model were each used with 1997 data to identify 0.5-percent-sized "top groups" of people most likely to be expensive in 1998. We compared the distributions of people, cost, and diseases commonly targeted for disease management for people in the two top groups and, as a bench mark, in the full population. PRINCIPAL FINDINGS: the prior cost- and DCG-identified top groups overlapped by only 38 percent. Each top group consisted of people with high year-two costs and high rates of diabetes, heart failure, major lung disease, and depression. The DCG top group identified people who are both somewhat more expensive ($27,292 vs. $25,981) and more likely ( 49.4 percent vs. 43.8 percent ) th an the prior-cost top group to have at least one of the diseases commonly targeted for disease management. The overlap group average cost was $46,219. CONCLUSIONS: Diagnosis-based risk models are at least as powerful as prior cost for identifying people who will be expensive. Combined cost and diagnostic data are even more powerful and more operation ally useful, especially because the diagnostic information identifies the medical problems that may be managed to achieve better out comes and lower costs.

Adolescent↗

PubMed2000

Long-term results of ammonia removal and transformation by biofiltration.

In this paper, long-term (>8 month) results of ammonia removal in biofilters was studied. Compost was used as the biofilter medium and activated carbon as an added material. The ammonia removal was normally >95% at influent ammonia concentrations of 20-500ppmv. According to the test results, the influent ammonia concentration should be <200ppmv (0.1570g ammonia/kg media per day) so that the effluent concentration of ammonia is <1.0mg/m(3) (the emission standard of China), and the biofiltration system can achieve good long-term performance. In the biofiltration system utilized in this study, the shortest retention time that the system could attain was 0.532min. However, the retention time can be decreased further without decreasing the ammonia removal efficiency. Countercurrent flow is favorable, as it enhances the moisture retention ability of the media. In the bioreactors, ammonia can be converted into the nitrate. The bioreactors have a stratification phenomenon for ammonia removal over the biofiltration depth, which implies that different parts of the bioreactor play different roles in the ammonia removing process.

Air Pollution↗

PubMed2000

Genomic structure, chromosomal localization and expression of the human LIM-homeobox gene LHX5.

The LIM-homeobox gene Lhx5 plays an essential role in the regulation of neuronal differentiation and migration during development of the central nervous system. Mice lacking Lhx5 function show severely disorganized brain morphology and are impaired in cognition and motor coordination. In this study, we characterized the cDNA and genomic organization of the human LHX5 gene and analyzed its expression and chromosomal location. The human gene was found to contain five exons encoding a protein composed of 402 amino acids that is 98.8% identical to mouse Lhx5. By reverse transcriptase polymerase chain reaction, LHX5 transcripts were detected in fetal brain and in various regions of the adult central nervous system including the spinal cord, the thalamus, and the cerebellum. Fluorescence in situ hybridization mapped the LHX5 gene to chromosome 12, position 12q24.31-24.32. These results provide a framework for future analysis of possible association of human hereditary disorders with mutations in LHX5.

Amino Acid Sequence↗

PubMed2000

Elevated plasma levels of transforming growth factor beta1 in patients with muscular dystrophy.

The progression of muscular weakness of patients suffering from muscular dystrophies directly correlates with the progressive loss of myofibers, accompanied by fibrosis. Since transforming growth factor beta1 (TGF-beta1) promotes tissue fibrosis, we measured the plasma TGF-beta1 level in patients with various muscular dystrophies in order to determine whether the level is elevated in patients with muscular dystrophy and if the level reflects the severity of tissue fibrosis. The plasma TGF-beta1 level was significantly elevated in patients with Duchenne muscular dystrophy and congenital muscular dystrophy (CMD), but not in those with Becker muscular dystrophy. Growth factors related to muscle fiber regeneration and fibrosis might be a key factor in the progression of muscular dystrophy and could be a target for therapeutic studies.

Adolescent↗

PubMed2000

Bid-induced cytochrome c release is mediated by a pathway independent of mitochondrial permeability transition pore and Bax.

Bid, a pro-apoptosis "BH3-only" member of the Bcl-2 family, can be cleaved by caspase-8 after Fas/TNF-R1 engagement. The p15 form of truncated Bid (tBid) translocates to mitochondria and induces cytochrome c release, leading to the activation of downstream caspases and apoptosis. In the current study, we investigated the mechanism by which tBid regulated cytochrome c release in terms of its relationship to mitochondrial permeability transition and Bax, another Bcl-2 family protein. We employed an in vitro reconstitution system as well as cell cultures and an animal model to reflect the physiological environment where Bid could be functional. We found that induction of cytochrome c release by tBid was not accompanied by a permeability transition even at high doses. Indeed, inhibition of permeability transition did not suppress the activity of tBid in vitro nor could they block Fas activation-induced, Bid-dependent hepatocyte apoptosis in cultures. Furthermore, Mg(2+), although inhibiting permeability transition, actually enhanced the ability of tBid to induce cytochrome c release. We also found that tBid did not require Bax to induce cytochrome c release in vitro. In addition, mice deficient in bax were still highly susceptible to anti-Fas-induced hepatocyte apoptosis, in which cytochrome c release was unaffected. Moreover, although Bax-induced cytochrome c release was not dependent on tBid, the two proteins could function synergistically. We conclude that Bid possesses the biochemical activity to induce cytochrome c release through a mechanism independent of mitochondrial permeability transition pore and Bax.

Animals↗