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Biomedical subjects

Yong Yang

Publications and source records attributed to Yong Yang.

121 records · Page 7Linked to original sources
PubMed2003

Inhibitory effects of antisense RNA of HAb18G/CD147 on invasion of hepatocellular carcinoma cells in vitro.

AIM: To study the inhibitory effects of antisense RNA of HAb18G/CD147 on invasion of hepatocellular carcinoma(HCC) cells in vitro. METHODS: Antisense RNA of HAb18G/CD147 vector PCI-asHAb18G was constructed by reversely inserting HAb18G/CD147 cDNA to eukaryotic expression vector PCI-neo. The HCC cell line HHCC was transfected by PCI-asHAb18G via cation liposome. Expression of HAb18G/CD147 of transfected cells selected by G418 (geneticin) was observed by immuno-histochemical SP staining and FACS (fluorescence activated cell sorting). Gelatin zymography was used to determine the effect of PCI-asHAb18G on reducing secretions of MMP-2 and MMP-9 of the transfected cells. Boyden chamber was employed to test the invasion of HCC cells in vitro. RESULTS: The construction of antisense RNA vector PCI-asHAb18G was verified correct by partial nucleotide sequencing and restricted endonuclease digestion. The expression of HAb18G/CD147 in transfected HHCC was inhibited by PCI-asHAb18G. Secretions of MMP-2 and MMP-9 of transfected HHCC were reduced and the invasion of transfected HHCC was inhibited compared to HHCC, respectively. CONCLUSION: Invasion of HCC cells can be inhibited by antisense RNA of HAb18G/CD147. HAb18G/CD147 may be used as a potential target of drugs for anti-invasion and metastasis of HCC.

Antigens, CD↗
PubMed2003

[Iodine-125 interstitial brachytherapy for malignant tumor].

OBJECTIVE: To assess the clinical effects of (125)I interstitial brachytherapy for malignant tumors. METHODS: One hundred and twelve patients with malignant tumors of stage II stage and III under went radical resection combined with (125)I intraoperative implantation. Seven days and three month after operation WBC count and immune markers were observed. Blood biochemistry ultrasonography and X-ray were performed to observe recurrence and metastasis of tumors per three months. RESULTS: In the 112 patients, 3 died of tumor recurrence in six months, and others survived with the longest time of 35 months. CONCLUSION: (125)I interstitial brachytherapy for malignant tumor is simple, safe and effective.

Adult↗
PubMed2003

The influence of oxygen-glucose deprivation on nitric oxide and intracellular Ca(2+) in cultured hippocampal neurons.

Nitric oxide (NO) was speculated to play an important role in the pathophysiology of cerebral ischemia. In this study, the effect of oxygen-glucose deprivation (OGD) on the cellular production of NO was investigated in cultured hippocampal neurons. Intracellular Ca(2+) was also detected as its closely relationship with NO. The generation of NO and changes in intracellular Ca(2+) were evaluated using confocal laser scanning microscopy with diaminofluorescein diacetate (DAF-2 DA), an NO probe, and Fluo-3, a Ca(2+) probe respectively. Extracellular glutamate level was also measured by HPLC with fluorescence detection. Results showed that OGD induced an increase in NO production and intracellular Ca(2+) concentration ([Ca(2+)](i)), the rise of DAF-2 and Fluo-3 fluorescence intensity was about 160% and 270% respectively; an increase of about 100% in glutamate level was observed after 20 min of OGD. NMDA inhibitor MK-801 significantly reduced the OGD-induced elevation of [Ca(2+)](i) and NO, DAF-2 and Fluo-3 fluorescence intensity uptake was inhibited by 69% and 74% respectively. The increase in NO production was also attenuated by extracellular Ca(2+) elimination and calmodulin (CaM) antagonist trifluoperazine dose-dependently. These results indicated that NO production increased during oxygen-glucose deprivation, and was greatly modulated by glutamate release, intracellular Ca(2+) change and Ca(2+)-CaM pathway.

Animals↗
PubMed2003

[Expression and purification of recombinant SARS coronavirus spike protein].

A novel coronavirus (SARS-coronavirus, SARS-CoV) was discovered in association with cases of severe acute respiratory syndrome (SARS) recently. The first step in coronavirus infection is binding of the viral spike protein to certain receptor on host cells. The spike protein is the main surface antigen of the coronavirus and there should be antibodies against spike protein in patients serum. Thus, to develop and expression protein fragment from spike protein gene are the purposes of this experiment. Partial spike gene fragments (751-1925 bp, 2005-3410 bp, 1-1925 bp and 32-3659 bp) and its intact gene were cloned into pET32 or pGEX vectors, and transformed into competent Escherichia coli BL21(DE3) (pLysS), respectively. 63, 78, 98, 160 and 164 kD fusion proteins were successfully expressed with amounts of 35%, 34%, 24%, 17% and 5% of total cell protein. The soluble parts of the cell crude extract were then partially purified by GST affinity chromatography.

Blotting, Western↗
PubMed2003

Cloning and expression of xeroderma pigmentosum complementation group A cDNA and the identification of its recombinant protein.

OBJECTIVE: To clone and express xeroderma pigmentosum, complementation group A (XPA) cDNA and to identify its recombinant protein. METHODS: Coding region of XPA cDNA was amplified from human tonsil cDNA by reverse transcription and nested PCR. The PCR product was cloned into pBluescript vector, confirmed by DNA sequencing, cloned in frame into a prokaryotic expression vector pTrcHis C and expressed in E. coli. TOP10. The recombinant fusion protein was identified by immunoblotting. RESULTS: The entire coding region of XPA cDNA was cloned and expressed. The fusion XPA protein was identified by anti-XPA monoclonal antibody on western blot. CONCLUSION: Cloning of human XPA cDNA and successful expression of recombinant XPA protein will be useful for the construction of a viral gene transfer vector for the gene therapy of XPA.

Base Sequence↗
PubMed2003

[Random amplified polymorphic DNA (RAPD) analysis of Drosophila simulans in the mainland of China].

The widespread distribution of Drosophila simulans in the mainland of China was found recently. Random amplified polymorphic DNA (RAPD) was used to analyzed DNA polymorphisms of 38 Drosophila simulans populations collected from the mainland of China. The origins of D. simulans in China were also discussed. Using 40 arbitary primers (10 bp), we made PCR amplifications under the optimized reaction conditions for RAPD that had been established in our laboratory. Our molecular phylogenetic tree constructed by UPGMA method showed as follows: (1) 38 populations are apparently classified into Northern cluster and Southern cluster, where NJ(Nanjing) can be considered as the boundary according to latitude. The populations in the Northern cluster can be further grouped into two sub-clusters, where BJ(Beijing) can be considered as the boundary according to latitude. The Northeast one consists of 10 populations, including Mohe(MH), Hailaer(HLR), Heihe(HH), Jiamusi(JMS), Haerbin(HRB), Changchun(CC), Shenyang(SY), Dandong(DD), Yanji(YJ), Tumen(TM); the other consists of 12 populations, including Beijing (BJ), Datong(DT), Huhehaote(HHHT), Yinchun(YC), Xinin(XN), Lanzhou(LZ), Taiyuan(TY), Shijiazhuang(SJZ), Yantai (YT), Jinan(JN), Xuzhou(XZ), Lianyungang(LYG). The southern cluster consists of the left 16 populations, including Zhengzhou (ZZ), Wuhan(WH), Shanghai(SH), Nanjing(NJ), Hangzhou(HZ), Chongqing(CQ), Nanchang(NC), Wenzhou(WZ), Changsha (CS), Guiyang(GY), Fuzhou(FZ), Kunming(KM), Xiamen(XM), Guangzhou(GZ), Nanning(NN), Hainan(HN). (2) The genetic distances among populations relate to the collection sites to a great extent, though there are some exceptions. According to the facts that we know, (1) D. simulans is an exotic species; (2) The invasion of D. simulans in the mainland of China took place in recent 30 years or so. (3) The widespread distribution of D. simulans in the mainland of China started in recent 10 years or so. Therefore, the results above might not be due to geographical differentiation, but due to genetic differences of initial founder individual(s) between geographical populations. Some of geographically adjacent populations, however, have common initial founder individual(s), which results in the classification of D. simulans populations according to their geographical relationship. We suggest that there are two possible reasons which result in the genetic differences of initial founder individual(s) between geographical populations, one is the D. simulans in the mainland of China had multiple origins, the other is founder effect and/or bottleneck effect that the D. simulans have experienced in the course of expansion.

Animals↗
PubMed2003

[Factor optimization for municipal domestic wastes treatment by earthworms and its concentration of heavy metals].

Simulated experiments, plot tests and applied stuties were conducted to determine the effects of the composition of municipal domestic wastes, their softening and culturing methods, and circumstance temperature on the treatment of municipal domestic wastes (MDW) by earthworms. The results showed that the decomposition rate of MDW and the multiplication rate of earthworms could be elevated by enhancing the C/N ratio of MDW, softening it with earthworms excrements, and culturing with indoor layer at 20 degrees C. Meanwhile, the treatment of MDW was also improved by the hybridization of tamed Chongqing Aisenia foetida and Caliginsoa. The concentration coefficient of heavy metals had no correlation with intenerating method, but were depended upon the types of heavy metals and the culturing method. Arsenic and cadmium were the most easily concentrated, while mercury oppositely. The concentration element in ridge culture was more easily than that in layer culture, and the concentration element in outdoors culture was more easily than that in indoors culturing.

Animals↗
PubMed2002

A novel splice site mutation in collagen type VII gene in a Chinese family with dominant dystrophic epidermolysis bullosa pruriginosa.

Dystrophic epidermolysis bullosa pruriginosa, a subtype of epidermolysis bullosa dystrophica and a heterogeneous inherited disease, is characterized by pruritus, excoriated nodular prurigo-like lesions, skin fragility, altered anchoring fibrils and loss of dermal-epidermal adhesion. Mutation in type VII collagen gene (COL7A1) is thought to be implicated in the underlying change for dystrophic epidermolysis bullosa pruriginosa. We report here a large family of dominant dystrophic epidermolysis bullosa pruriginosa. Mutation analysis using polymerase chain reaction and direct sequencing demonstrated a novel nucleotide substitution of 6899A-->G in exon 87 in one COL7A1 allele of the proband and 18 affected family members. This substitution was not found in 100 normal alleles. Polymerase chain reaction and sequencing of the cDNA, reverse transcribed from the proband's peripheral lymphocyte RNA, suggest that this mutation causes aberrant COL7A1 mRNA splicing of exon 87 skipping. Clinical features and pedigree analysis suggest that 6899A-->G substitution is a mutation with full penetrance and variable expressivity.

Adolescent↗
PubMed2002

A three-source model for the calculation of head scatter factors.

Accurate determination of the head scatter factor Sc is an important issue, especially for intensity modulated radiation therapy, where the segmented fields are often very irregular and much less than the collimator jaw settings. In this work, we report an Sc calculation algorithm for symmetric, asymmetric, and irregular open fields shaped by the tertiary collimator (a multileaf collimator or blocks) at different source-to-chamber distance. The algorithm was based on a three-source model, in which the photon radiation to the point of calculation was treated as if it originated from three effective sources: one source for the primary photons from the target and two extra-focal photon sources for the scattered photons from the primary collimator and the flattening filter, respectively. The field mapping method proposed by Kim et al. [Phys. Med. Biol. 43, 1593-1604 (1998)] was extended to two extra-focal source planes and the scatter contributions were integrated over the projected areas (determined by the detector's eye view) in the three source planes considering the source intensity distributions. The algorithm was implemented using Microsoft Visual C/C++ in the MS Windows environment. The only input data required were head scatter factors for symmetric square fields, which are normally acquired during machine commissioning. A large number of different fields were used to evaluate the algorithm and the results were compared with measurements. We found that most of the calculated Sc's agreed with the measured values to within 0.4%. The algorithm can also be easily applied to deal with irregular fields shaped by a multileaf collimator that replaces the upper or lower collimator jaws.

Algorithms↗
PubMed2002

[Diagnosis and treatment of complete necrosis of the ureter after cadaveric renal transplantation].

OBJECTIVE: To deepen the understanding of patients with complete necrosis of the ureter after renal transplantation for early diagnosis and treatment. METHODS: Of 5 patients with complete necrosis of the ureter after renal transplantatioin between January 1991 and April 2001 in our hospital, 4 were male and 1 was female (mean age, 35 years). Seven to 12 days after renal transplantation, native pyeloureterestomy was performed for 1 patient, and the remaining 4 patients received the cutting of the diatal necrosis ureter and vesicoureterostomy because of urine leakage. Six to seven weeks later when the ureter stents were pull out, native pyeloureterestomy or pyeloureteroplasty was performed for the 4 patients because of uropenia and hydronephrosis. RESULTS: Five patients showed normal function of the kidney postopcreation (follow up: 6 - 12 months) without hydronephrosis. CONCLUSIONS: When distal necrosis of the ureter is observed after renal transplantation, complete necrosis of the ureter may occur. Native pyeloureterostomy or pyeloureteroplasty is an effective treatment.

Adult↗
PubMed2001

Interface-Induced Coarsening Process in Polymer Blends.

The coarsening process of the droplets in a two-phase polymer blend (PP/EVAc) was studied under two-dimensional and three-dimensional conditions using a phase contrast microscope and computer image analyzer. The results showed that under three-dimensional conditions the growth of the droplet's radius with time follows r(3) approximately t(1.01), corresponding to the evaporation-condensation theory of Lifshitz-Slyozov, r(3) approximately t, while under two-dimensional conditions the growth law is r(3) approximately t(1.31). The growth rate of the droplets under two-dimensional conditions is faster than that under three-dimensional conditions. This difference is caused by an interfacial interaction (wetting effects) between the substrates and polymer blend. The existence of the interface promoted the coarsening process of the polymer blend under two-dimensional conditions. Copyright 2001 Academic Press.

Journal Article↗
PubMedDate not supplied

Changes in body fat measured by DEXA in patients taking different formulations of stavudine.

BACKGROUND: Lipoatrophy is a frequent complication of chronic stavudine therapy. Stavudine extended release formulation (stavudine ER) gives lower peak and higher trough levels than the immediate release formulation (stavudine IR), and we hypothesized that the lower peak might result in less lipoatrophy. OBJECTIVE: To compare the rate of peripheral lipoatrophy between patients taking stavudine ER and stavudine IR. METHOD: Body composition was measured by dual energy X-ray absorptiometry (DEXA) every 6 months for 18 months in 29 patients taking either stavudine ER or IR as part of a randomized controlled clinical trial. RESULTS: DEXA fat measurements did not differ between the ER and IR groups at baseline, after a median of 32 months on stavudine-containing treatment. Over the 18 months of follow-up in the whole cohort limb fat decreased by a mean of 0.29 +/- 0.50 kg (p = .01) and leg fat percent decreased by a mean of 1.23% +/- 1.92% (p = .001), whereas trunk fat and trunk-to-limb fat percent ratio did not change significantly. There was no significant difference between the ER and IR groups in the rate of change of any of the fat parameters. At study completion, the proportion of patients with clinical lipodystrophy was similar in the stavudine ER and stavudine IR groups (67% and 64%, respectively; p = .893). CONCLUSION: Stavudine ER does not appear to cause less peripheral lipoatrophy.

Absorptiometry, Photon↗