Biomedical subjects

Yong Yang

Publications and source records attributed to Yong Yang.

At least 55 records · Page 3Linked to original sources

PubMed2006

Model-based image reconstruction for four-dimensional PET.

Positron emission tonography (PET) is useful in diagnosis and radiation treatment planning for a variety of cancers. For patients with cancers in thoracic or upper abdominal region, the respiratory motion produces large distortions in the tumor shape and size, affecting the accuracy in both diagnosis and treatment. Four-dimensional (4D) (gated) PET aims to reduce the motion artifacts and to provide accurate measurement of the tumor volume and the tracer concentration. A major issue in 4D PET is the lack of statistics. Since the collected photons are divided into several frames in the 4D PET scan, the quality of each reconstructed frame degrades as the number of frames increases. The increased noise in each frame heavily degrades the quantitative accuracy of the PET imaging. In this work, we propose a method to enhance the performance of 4D PET by developing a new technique of 4D PET reconstruction with incorporation of an organ motion model derived from 4D-CT images. The method is based on the well-known maximum-likelihood expectation-maximization (ML-EM) algorithm. During the processes of forward- and backward-projection in the ML-EM iterations, all projection data acquired at different phases are combined together to update the emission map with the aid of deformable model, the statistics is therefore greatly improved. The proposed algorithm was first evaluated with computer simulations using a mathematical dynamic phantom. Experiment with a moving physical phantom was then carried out to demonstrate the accuracy of the proposed method and the increase of signal-to-noise ratio over three-dimensional PET. Finally, the 4D PET reconstruction was applied to a patient case.

Algorithms↗

PubMed2006

Four-dimensional cone-beam computed tomography using an on-board imager.

On-board cone-beam computed tomography (CBCT) has recently become available to provide volumetric information of a patient in the treatment position, and holds promises for improved target localization and irradiation dose verification. The design of currently available on-board CBCT, however, is far from optimal. Its quality is adversely influenced by many factors, such as scatter, beam hardening, and intra-scanning organ motion. In this work we quantitatively study the influence of organ motion on CBCT imaging and investigate a strategy to acquire high quality phase-resolved [four-dimensional (4D)] CBCT images based on phase binning of the CBCT projection data. An efficient and robust method for binning CBCT data according to the patient's respiratory phase derived in the projection space was developed. The phase-binned projections were reconstructed using the conventional Feldkamp algorithm to yield 4D CBCT images. Both phantom and patient studies were carried out to validate the technique and to optimize the 4D CBCT data acquisition protocol. Several factors that are important to the clinical implementation of the technique, such as the image quality, scanning time, number of projections, and radiation dose, were analyzed for various scanning schemes. The general references drawn from this study are: (i) reliable phase binning of CBCT projections is accomplishable with the aid of external or internal marker and simple analysis of its trace in the projection space, and (ii) artifact-free 4D CBCT images can be obtained without increasing the patient radiation dose as compared to the current 3D CBCT scan.

Algorithms↗

PubMed2006

Diversity of telomere palindromic sequences and replication genes among Streptomyces linear plasmids.

Streptomyces sp. linear plasmids and linear chromosomes usually contain conserved terminal palindromic sequences bound by the conserved telomeric proteins Tap and Tp, encoded by the tap and tpg genes, respectively, as well as plasmid loci required for DNA replication in circular mode when the telomeres are deleted. These consist of iterons and an adjacent rep gene. By using PCR, we found that 8 of 17 newly detected linear plasmids in Streptomyces strains lack typical telomeric tap and tpg sequences. Instead, two novel telomeres in plasmids pRL1 and pRL2 from the eight strains and one conserved telomere in pFRL1 from the other strains were identified, while multiple short palindromes were also found in the plasmids. The complete nucleotide sequence of pRL2 revealed a gene encoding a protein containing two domains, resembling Tap of Streptomyces and a helicase of Thiobacillus, and an adjacent gene encoding a protein similar to Tpg of Streptomyces and a portion of the telomere terminal protein pTP of adenoviruses. No typical iterons-rep loci were found in the three plasmids. These results indicate an unexpected diversity of telomere palindromic sequences and replication genes among Streptomyces linear plasmids.

Amino Acid Sequence↗

PubMed2006

The anticancer activities of wogonin in murine sarcoma S180 both in vitro and in vivo.

The anticancer effects of wogonin on murine sarcoma S180 both in vitro and in vivo were investigated, and its pro-apoptotic molecular mechanism was further studied. Wogonin treatment resulted in significant inhibition of S180 cells in a concentration-dependent manner detected by MTT assay. The IC50 value for 48 h was (7.37+/-1.53) x 10(-5) M. Typical morphological changes and apoptosis bleb phenomenon in S180 cells exposed to wogonin were distinctly observed by the inverted light microscope and the fluorescence microscope, respectively. According to protocols of transplanted tumor research, mice were transplanted with tumor cells S180. The weight of tumor and the peripheral leucocyte count were observed after the treatment of wogonin. The significant suppression of tumor growth was observed, and the peripheral leucocyte count of S180-bearing mice remained no significant changes compared with control group. After the treatment of 40 mg/kg wogonin, the inhibitory rate of tumor weight was 53.01%. Additional DNA fragmentation assay showed that wogonin induced apoptosis on murine sarcoma S180 tissue. RT-PCR results indicated that the increasing mRNA levels of bax and p53 and the decreasing mRNA level of bcl-2 were induced by wogonin. Western-blot assay showed that the increasing protein level of bax and the decreasing protein level of bcl-2 were induced by wogonin. Collectively, wogonin could induce apoptosis in murine sarcoma S180 thereby inhibiting the tumor growth both in vitro and in vivo. The pro-apoptotic effects might be related to the improvement of mRNA level of p53, the improvement of mRNA and protein levels of bax, and the reduction of mRNA and protein levels of bcl-2.

Animals↗

PubMed2006

Proline-rich tyrosine kinase2 is involved in F-actin organization during in vitro maturation of rat oocyte.

Microfilaments (actin filaments) regulate various dynamic events during meiotic maturation. Relatively, little is known about the regulation of microfilament organization in mammalian oocytes. Proline-rich tyrosine kinase2 (Pyk2), a protein tyrosine kinase related to focal adhesion kinase (FAK) is essential in actin filaments organization. The present study was to examine the expression and localization of Pyk2, and in particular, its function during rat oocyte maturation. For the first time, by using Western blot and confocal laser scanning microscopy, we detected the expression of Pyk2 in rat oocytes and found that Pyk2 and Try402 phospho-Pyk2 were localized uniformly at the cell cortex and surrounded the germinal vesicle (GV) or the condensed chromosomes at the GV stage or after GV breakdown. At the metaphase and the beginning of anaphase, Pyk2 distributed asymmetrically both in the ooplasm and the cortex with a marked staining associated with the chromosomes and the region overlying the meiotic spindle. At telophase, Pyk2 was observed in the cleavage furrows in addition to its cortex and cytoplasm localization. The dynamics of Pyk2 were similar to that of F-actin, and this kinase was found to co-localize with microfilaments in several developmental stages during rat oocyte maturation. Microinjection of Pyk2 antibody demolished the microfilaments assembly and also inhibited the first polar body (PB1) emission. These findings suggest an important role of Pyk2 for rat oocyte maturation by regulating the organization of actin filaments.

Actin Cytoskeleton↗

PubMed2006

Study on the technology of nitric oxide (NO) detection in vitro and in vivo.

To reveal the intracellular distribution of nitric oxide (NO) in single cell and to detect NO quantitatively in animal models, various methods are developed. A confocal microscope and 3D visualization technique were applied to visualize NO concentration in arbitrary directions and in different sections of cells. It was shown that NO distributions in cultured neurons of rat hipopocampus were not homogeneous. A kind of highly sensitive and selective NO electrode was utilized to measure the NO concentration in SD rat hippocampus, simultaneously with blood pressure and ECG recording. By the administration of N(G)-nitro-L-arginine methylester (L-NAME), the changes of NO level in the hippocampus in vivo were detected. It was shown that the NO level decreased greatly when NOS was inhibited by L-NAME with significant increase in blood pressure. The developed methods may be helpful to investigate the physiological mechanism of NO and its role in pathology.

Animals↗

PubMed2006

[Biodiversity of halophilic archaea isolated from two salt lakes in Xin-Jiang region of China].

There are more than 1000 salt lakes situated in northern and western regions of China and 790 of these salt lakes are in Xinjiang Uigur Autonomous Region and Qinghai, Tibet, Inner Mongolia. To better understand halophilic archaeal diversity of salt lakes in Xinjiang, water and sediment samples were collected from two salt lakes, namely Aibi salt lake and Aiding salt lake, and the halophilic archaeal diversity of these samples was determined. Totally eighty-six halophilic archeal strains, of which 56 isolated from Aibi salt lake and 30 isolated from Aiding salt lake, were isolated respectively using CM agar medium. All the strains were subjected to 16S rRNA gene sequencing analysis. Similarity analysis based on 16S rRNA gene sequences of all these strains indicated that the isolates from Aibi salt lake belong to 11 different species of genera Haloarcula, Halobacterium, Halorubrum, Haloterrigena, Natrinema and Natronorubrum, and that the isolates from Aiding salt lake belong to 8 different species of genera Haloarcula, Halobiforma, Halorubrum, Haloterrigena, Natrinema. Among the 86 strains, members of Natronorubrum Natrinema, Halorubrum and Haloterrigena, are dominant groups in Aibi salt lake. However, the dominant group in Aibi salt lake are the members of Natrinema, Halorubrum and Haloterrigena. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains ABH13, ABH 14, ABH 15, ABH 18, ABH 31 and ABH 33 may represent a novel species of Natronorubrum; ABH12, ABH32 and AD30 two novel species of Halorubrum; ABH17 and ABH25, ABH51, ABH52, ABH56 two novel species of Haloterrigena respectively; strain ABH19 a novel species of Haloarcula; strain ABHO7 a novel species of Halobacterium. The Shannon-Wiener's index of Aibi salt lake is 1.899, the same index of Aiding salt lake is 1.317, which indicated that the biodiversity of halophilic archaea from Aibi salt lake was slightly higher than that of Aiding salt lake. Different characteristics in pH of salt concentrations, average annual precipitation, annual evaporation and mankind's impact on two salt lakes might play important roles on halophilic archaeal diversity of two salt lakes.

Biodiversity↗

PubMed2006

[Highly sensitive tunable diode laser absorption spectroscopy of CO2 around 1.31 microm].

Fifteen new absorption lines were observed when studying CO2 absorption spectroscopy by wavelength modulation (WM) technique with a DFB laser. The line intensity we can detect is 2.251 63 x 10(-27) cm(-1) x (moleculecm(-2))(-1) at 6.67 x 10(2) Pa pressure, corresponding to an absorbance of 3. 88 x 10(-8). The overtone spectra of CO2 around 1.31 microm have been measured with a tunable diode laser and the corresponding spectral parameters (positions, intensities, and self-broadening coefficients) are presented.

English Abstract↗

PubMed2006

[Optimization preparation of chansu-loaded solid lipid nanoparticles by central composite design and response surface method].

OBJECTIVE: To optimize the formulation of chansu-loaded solid lipid nanoparticles (Cs-SLN). METHOD: Cs-SLN was prepared by cold homogenization technique. The effects of influence factors such as the weight of compritol 888 ATO, soybean lecithin and poloxamer 188, on mean diameter, entrapment efficiency, drug loading and overall desirability were investigated by using central composite design and response surface method. The data were imitated using multi-linear equation and second-order polynomial equation. RESULT: The latter was prior to the former considering from multiple correlation coefficients. Under the optimal conditions, the mean diameter, entrapment efficiency, drug loading of the Cs-SLN were 71.5 nm, 92.45% and 5.26%. CONCLUSION: The optimized preparation technique for Cs-SLN is stable, feasible and high inclusion rate. It can be used for production of Cs-SLN.

Amphibian Venoms↗

PubMed2006

[Anti-dementia effects of grape peel extracts experiment study].

OBJECTIVE: To study anti-dementia effects and mechanism of grape peel extracts on imitative dementia rats modle. METHODS: The imitative dementia rats modle were established using health male Wistar rats by intraperitoneal injection of D-galactose and NaNO2, simultaneity, administer physiological saline solution, Piracetam Tablets, low dose grape peel extracts, middle dose grape peel extracts, high dose grape peel extracts to intervene separately. Using neurobehavioral tests, antioxidation genus, cholinesterase genus and nitric oxide synthase, histopathological and morphological parameters and immunohistochemical methods etc measure index to observe and evaluate. RESULTS: Grape peel extracts can significantly ameliorate learning and memory function of imitative dementia rats modle, and improve SOD enzyme, NOS enzyme, CAT enzyme activity in rats brain, inhibite MDA enzyme, AchE enzyme activity, reduce the expression of beta-APP-positive immunoreactive neurocytes (beta-APP+) and beta-amyloid-positive immunoreactive neurocytes (beta-AP+) in cerebra cortex and Hippocampus. CONCLUSION: Grape peel extracts can inhibite oxygen free radicel to form, ameliorate cholinomimetic neural function, enhance NOS enzyme activity in the hippocampus and cerebra cortex, reduce the development of beta-AP deposited macula, grape peel extracts probability have a preventive action against early-aged dementia.

Animals↗

PubMed2006

[Molecular phylogenetic relationships of Drosophila immigrans species group based on H2a-H2b spacer and Cyt b sequences].

In order to investigate molecular phylogenetic relationships of Drosophila immigrans species group, nucleotide sequences of H2a-H2b spacer regions and partial nucleotide sequences of Cytochrome b gene for five specieses subgroup in Drosophila immigrans species group and D. hydei which was selected as outgroup were acquired. Phylogenetic trees were reconstructed using maximum parsimony, maximum likelihood, neighbor joining and Bayesian methods based on H2a-H2b and Cyt b DNA sequences. The results indicated that Drosophila curviceps species subgroup is located at the base of molecular trees, diverged first in this group; the second clade is Drosophila quadrilineata species subgroup; the third is Drosophila hypocausta species subgroup; the fourth is Drosophila immigrans species subgroup; Drosophila nasuta species subgroup is the last diverged clade. Moreover, the phylogentic relationships of seven specieses in Drosophila nasuta subgroup was investigated.

Animals↗

PubMed2006

[Effects of Broad bean wilt virus 2 isolate infection on photosynthetic activities and chloroplast ultrastructure in broad bean leaves].

The effects of Broad bean wilt virus 2 (BBWV 2) isolate B935 and PV131 infection on photosynthetic activities and chloroplast ultrastructure in broad bean (Vicia faba) were investigated. As the disease progressed, net photosynthetic rate (P(n)), stomatal conductance (G(s)) of leaves, the chlorophyll content and chlorophyll a/b ratio decreased while the intercellular CO(2) concentration (C(i)) of leaves rose in comparison with that of the healthy plants (Figs. 1, 2). After BBWV 2 infection, F(v)/F(m), F(v)'/F(m)', Phi(PSII) and q(P) values all became lower, but the NPQ values were higher, than the healthy control plants (Fig. 3). Electron microscopy showed that BBWV 2 infection disrupted the chloroplast structure. Most of the B935-infected chloroplasts showed inhibition of lamellar development or membrane vesiculation (Fig. 4B, C) and PV131-infected chloroplasts showed swollen or disintegrated membrane (Fig. 4D-F). Chloroplasts of PV131-infected leaves were different from those of normal ones to a higher degree than those of the B935-infected ones, which suggests that the disruption of chloroplast structure by virus invasion is responsible for the suppression of photosynthesis, which is more serious with PV131 than with B935.

Chlorophyll↗

PubMed2006

[Effects of astragalus membranaceus on TH cell subset function in children with recurrent tonsillitis].

OBJECTIVE: To observe the TH cell subset function in children with recurrent tonsillitis (RT) at the remission stage and to study the effects of astragalus membranacus (AM) on TH cell subset function. METHODS: The peripheral blood mononuclear cells (PBMC) from 27 children with RT at the remission stage were stimulated with either phytohemagalutinin (PHA) (RT-PHA group) or PHA together with AM (RT-AM group) and were then cultured in vitro for 48 hrs. The samples from 21 healthy children stimulated with PHA were used as the Control group. The levels of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) in the supernatants of PBMC were detected using ELISA. RESULTS: The IFN-gamma level and the ratio of IFN-gamma/IL-4 in the RT-PHA group were statistically lower than those in the Control group (P < 0.01). The level of IFN-gamma and the ratio of IFN-gamma/IL-4 in the RT-AM group were markedly higher than those in the RT-PHA group (P < 0.01), but were significantly lower than those in the Control group (P < 0.05). There were no differences in the IL-4 level among the three groups. CONCLUSIONS: TH1 cell subset dysfunction may exit in RT children at the remission stage, suggesting that TH1 cell subset dysfunction plays an important role in the pathogenesis of RT. AM can improve TH1 cell subset function and therefore shows an important significance in treating RT.

Adolescent↗

PubMed2006

[Intrathecal administration of HSV-I amplicon vector-mediated HPPE gene therapy of nocicepion in rats with formalin pain].

OBJECTIVE: To investigate the antinociceptive effect of intrathecal administration of HSV-I amplicon vector-mediated HPPE. METHODS: Sprague Dawley rats (290+/-30) g were randomly divided into pHSVIRES-HPPE-LacZ (SHPZ) group, pHSVIRES-LacZ (SHZ) group, and saline group (NS), and 3 d, 1 week, 2 weeks, 3 weeks, 4 weeks, and 5 weeks group,which were anesthetized with 10% chlroral hydrate 300- 350 mg/kg. A microspinal catheter was inserted into the lumbar subarachnoid space. Rats were intrathecally delivered with recombinant HSV-I amplicon vector SHPZ, SHZ or NS. The HPPE expression was detected by reverse transcription-polymerase chain reaction (RT-PCR) and radioimmune assay. Formalin 50 microL (5%) was injected into the left hindpaw, pain intensity scoring (PIS) was used to assess the antinociceptive effect. RESULTS: After in vivo transferring,neurocyte demonstrated strong positive signals with X-gal immunohistochemical staining. RT-PCR and L-enkephalin radioimmune assay found that the neural cells transferred foreign gene (HPPE) had effective expression. Intrathecal delivery of SHPZ showed antinociceptive effects on formalin induced pain for 5 weeks compared with SHZ. CONCLUSION: This amplicon virus can transfer HPPE into rat central nerve system neural cells and express efficiently, suggesting SHPZ is satisfactory treatment for gene therapy for chronic pain. Intrathecal delivery SHPZ demonstrated antinociceptive effects on formalin induced pain.

Animals↗

PubMed2006

[Effect of intrathecal katemine on the expression of nNOS in spinal dorsal horn in rats with formalin pain].

OBJECTIVE: To investigate the expression of neuronal nitric oxide synthase (nNOS) in spinal dorsal horn and the effect of intrathecal katemine on the expression of nNOS in the rats with formalin-induced pain. METHODS: Thirty-two Sprague-Dawley rats were randomly divided into 4 groups (n=8 in each group): a control group (C), an intrathecal saline group (NS), a katemine 50 microg group (K1), and a katemine 100 microg group (K2). The rats that were anesthetized with 10% chlroral hydrate 300 - 350 mg/kg by abdominal injection were intrathecally inserted a microspinal catheter into the lumbar region according to the method of modified Yaksh. After 5 days ,the rats in Group NS, K1 and K2 were intrathecal 20 microL saline or 10 microL katemine (50, 100 microg) followed by 10 microL saline, respectively. Thirty minutes later, 5% formalin 50 microL was subcutaneously injected into the left hindpaw. Pain intensity scoring (PIS) was used to assess antinociceptive behavior within 1 h after the formalin injection. The expression of nNOS in the spinal dorsal horn of L5 segment was assayed using immunohistochemistry 24 h later. RESULTS: Compared with Group NS, PIS of Group K1 and K2 was decreased obviously (P<0.01) in the second phase of formalin pain. The number of immunoreactive soma and immunohistochemistic dying grade of nNOS in the spinal dorsal horn of L5 segment was higher in Group NS than that in Group C (P<0.01), but Group K1 and K2 were lower than Group NS (P<0.01). CONCLUSION: There was significant antinociception of intrathecal katemine in rats with formalin pain. Intrathecal katemine significantly inhibited the increase of nNOS expression in the spinal dorsal horn of formalin-induced pain, suggesting nNOS plays an important role in nociceptive transmission and modulation of the spinal cord.

Analgesics↗

PubMed2006

Temporal variations of CO2 concentration near land surface and its response to meteorological variables in Heihe River Basin, northwest China.

Atmospheric CO2 concentration (CC) near land surface and meteorological variables have been measured at four sites, named Yeniugou (alpine meadow and permafrost), Xishui (mountainous forest), Linze (oasis edge) and Ejina (lower desert), respectively, in Heihe River Basin, northwest China. The results showed that, the half hourly CC at night was larger than in daytime, and the daily averaged CC was the largest in winter. The averaged CC of 932 d at the Linze was about 418 ppm, was about 366 ppm in the 762 d at the Ejina. In the same period from September 23 to November 9, 2004, the averaged CC was about 625, 334, 436 and 353 ppm, at Yeniugou, Xishui, Linze and Ejina, respectively. The linear relationship between daily averaged CC and air temperature T was negative, between CC and relative humidity (RH) was positive. The linear CC-atmospheric pressure (AP) relationship was negative at the Linze and Yeniugou, was positive at the Ejina. The relationship between CC and global radiation R was exponent, and soil temperature Ts was negative linear, and soil water content was complex. The correlation between CC and wind speed was not existent. Using meteorological variables together to simulate CC, could give good results.

Air↗

PubMed2006

[Aildenafil citrate: a new potent and highly selective phosphodiesterase type 5 inhibitor for the treatment of erectile dysfunction].

OBJECTIVE: To evaluate the efficacy and safety of aildenafil citrate, an oral phosphodiesterase type 5 inhibitor, in the treatment of erectile dysfunction. METHODS: Integrated analyses were made of 8-week, randomized, double-blind, placebo-controlled phase 2 clinical trials involving 250 men with mild-to-severe erectile dysfunction of various etiologies who received aildenafil citrate 30 or 60 mg (n = 167) or placebo (n = 83). RESULTS: The statistic results of International Index of Erectile Function, Patient Sexual Encounter Profile (SEP) diaries and Global Assessment Question (GAQ) were significantly higher in the aildenafil citrate patients than in the placebo controls. The main drug-related adverse events were flushing, headache, dizziness and naupathia, which were mild and could be self-relieved. CONCLUSION: The aildenafil citrate therapy significantly ameliorated erectile function and was well tolerated by a wide range of patients with erectile dysfunction.

Administration, Oral↗

PubMed2006

[Treatment and prognosis of scrotal extramammary Paget's disease: a report of 23 cases].

OBJECTIVE: To evaluate the clinical manifestation, management and prognostic characteristics of scrotal extramammary Pagets disease (EMPD). METHODS: Twenty-three cases of EMPD were identified and retrospectively reviewed, and the clinical findings, surgical treatment, pathologic features and prognostic characteristics were evaluated. The patients ranged in age from 49 to 72 years (mean 62. 4 years). The diagnoses were delayed by 12 to 132 months (67. 6 on average) in 9 cases at Stage A1 , 12 at A2, 1 at B and 1 at D. The rate of initial misdiagnosis was 91.3% (21/23). Twenty of the patients underwent operations, 2 received radiotherapy and 1 chemotherapy. RESULTS: Twenty-two patients of the total number were followed up for 7 to 223 months, averaging at 119, therapy and 1 chemotherapy. of whom 12 remained cancer free, 1 died of tumor, 3 died of intercurrent disease, 4 experienced local recurrence, 1 relapsed with inguinal lymph node metastasis and 1 developed inguinal lymph node metastasis exclusively. Those with relapses received the second surgery, and 5 of them survived without cancer and 1 died of intercurrent disease. CONCLUSION: The primary treatment of choice for scrotal EMPD is radical excision. Precise, histological examination before and during the operation is of crucial importance. The positive excisal margins are one of the key causes of local recurrence, and the involvement of dermis by Pagets cells may suggest possible metastasis. Scrotal EMPD tends to occur as a slowly growing lesion, mainly in the elderly, and has a good prognosis in cases of non-invasion. Otherwise the prognosis is poor.

Aged↗