Room-temperature hybridization of target DNA with microarrays in concentrated solutions of guanidine thiocyanate.
Explore the source record for details and available documents.
Biotechnology↗
Biomedical subjects
Y Li
Publications and source records attributed to Y Li.
A comparison of initial treatment with losartan/HCTZ versus losartan monotherapy in chinese patients with mild to moderate essential hypertension.
The antihypertensive efficacy and tolerability of losartan/hydrochlorothiazide (HCTZ) and losartan monotherapy as initial treatment were compared in a double-blind trial in Chinese patients with mild to moderate essential hypertension. Patients were randomised to initial treatment with either losartan/HCTZ (50 mg/12.5 mg) or losartan alone (50 mg). The doses were doubled after four weeks if diastolic blood pressure (SiDBP)was >90 mmHg. Both losartan/HCTZ and losartan alone significantly reduced SiDBP and SiSBP from baseline at the first measurement at 4 weeks (-10.1/-15.3 and -6.1/-6.9 mmHg, respectively; p<0.001) and at 8 weeks (-13.1/-18.5 and -8.7/-10.9 mmHg; p<0.001). The reductions with losartan/HCTZ were significantly greater than with losartan alone at weeks 4 and 8 (p<0.001). Both regimens were similarly well tolerated. In conclusion, initial therapy with losartan/HCTZ is effective and well tolerated in the treatment of Chinese patients with mild to moderate essential hypertension and produces a greater reduction in blood pressure than losartan alone.
Adolescent↗
Field assessment of recombinant Schistosoma japonicum 26 kDa glutathione S-transferase in Chinese water buffaloes.
We have shown previously that anti-fecundity immunity can be induced experimentally against recombinant 26 kDa glutathione S-transferase (reSjc26GST) in Chinese water buffaloes (Bos buffelus), important reservoir hosts for Schistosoma japonicum in China. In the field study described here, we immunized buffaloes with reSjc26GST to induce protective immunity against S. japonicum and to evaluate its effectiveness in controlling schistosomiasis japonica. We selected two villages as test and control groups in inside-embankment areas endemic for schistosomiasis japonica. The buffaloes in the test village were vaccinated with reSjc26GST, whereas those in the control village were not. The indicators of the effect of the vaccine included the generation of specific IgG antibodies in the vaccinated buffaloes, changes in the prevalence and infection intensity in buffaloes and village children, changes in the density of infected snails, and changes in the infectivity of water bodies (assessed by sentinel mice) in transmission areas adjacent to both villages. Twenty months after vaccination, the infection rate of buffaloes in the test village was decreased by 60.4% (from an initial prevalence of 13.5% to 5.4%), and 67.9% when compared with that in the control village (initial prevalence of 16.7%). However, the infection rate in village children remained unchanged. The density of infected snails decreased by 71.4%, from 0.0049/0.11 m2 to 0.0014/0.11m2 in the high transmission area outside the embankment in the test village. There was no change in the infectivity of the water body transmission areas between the test and control villages. The levels of specific antibodies to reSjc26GST showed a continuous increase after vaccination. These results indicate that protective immunity was induced and maintained in buffaloes after vaccination with reSjc26GST. The vaccine could thus play a significant role in reducing S. japonicum transmission caused by water buffaloes in the Lake region of China.
Animals↗
Genetic transformation of two species of orchid by biolistic bombardment.
We report here the transformation of two species of orchid, Dendrobium phalaenopsis and D. nobile,by biolistic bombardment. Calli or protocorm-like bodies (PLBs) were used as target explants. Gold particles (1.0 microm) coated with plasmid DNA (pCAMBIA1301) encoding an intron-containing beta-glucuronidase gene (gus-int) and a hygromycin phosphotransferase (hpt) gene were introduced into the PLBs or calli using the Bio-Rad PDS-1000/He Biolistic Particle Delivery System. Calli and PLBs were then chopped up and pre-cultured in 1/2-strength MS medium supplemented with 0.4 M mannitol for a 1-h osmoticum treatment before bombardment. Immediately after bombardment, the calli and PLBs were transferred to 1/2-strength MS medium without mannitol for recovery. Putatively transformed plantlets were obtained by selection and regeneration on medium supplemented with 30 mg/l hygromycin. The highest efficiency of transformation was obtained when selection was conducted at 2 days post-bombardment. For D. phalaenopsis and D. nobile, respectively, about 12% and 2% of the bombarded calli or PLBs produced independent transgenic plants. Integration and expression of the transgenes were confirmed by Southern hybridization and Northern hybridization. No nontransformed plants were regenerated, indicating a tight selection scheme. However, separate incorporation of the gus gene and the hpt gene was observed, and in one transgenic line the gus gene was integrated into the genome of the transgenic plant, but not expressed.
Biolistics↗
Establishment of a hepatocellular carcinoma cell line with unique metastatic characteristics through in vivo selection and screening for metastasis-related genes through cDNA microarray.
PURPOSE: To establish a hepatocellular carcinoma (HCC) cell line from lung metastatic lesions of human HCC in nude mice so as to provide a suitable model for the study of lung-metastasis-related molecular mechanisms. METHODS: HCC clone cells MHCC97-H were inoculated into BALB/c nude mice, and the pulmonary metastatic lesions were harvested and re-implanted into nude mice for the second round of in vivo selection. The same procedure was repeated twice. A new cell line from the third round of lung metastases was established. RESULTS: A human HCC cell line with unique metastatic characteristics was established by in vivo selection. This cell line, designated as HCCLM3, was polygonal epithelial cell with hypotriploid karyotype and population doubling time of 34.9 h. The cells were positive for alpha fetoprotein (AFP), albumin, cytokeratin 8 (CK8), and negative for hepatitis B surface antigen (HBsAg) by immunocytochemistry. Fluorescence polymerase chain reaction (PCR) showed HBV DNA integration in the cellular genome. When 5 x 10(6) cells were injected subcutaneously into nude mice, tumorigenicity was 100%, with a latency period of 11+/-1 days. Five weeks after s.c. injection, the pulmonary metastatic rate was 100%, the median number of lung metastases being 121 per mouse. After orthotopic implantation of tumor tissue into nude mouse liver for 35 days, widespread loco-regional and distant metastases occurred, with 100% abdominal wall metastases, 80% intra-abdominal cavity metastases, 100% intrahepatic metastases, 70% diaphragm metastases, and 100% pulmonary metastases. The median number of lung metastatic lesions was 268 per mouse. Gene expression profile of HCCLM3 was compared by cDNA microarray with MHCC97-L, a clonal cell strain from the same parental cell line but with low metastatic potential; 25 differentially expressed genes were identified, 18 of which showed decreased expression and seven increased expression in HCCLM3, including the decreased expression of cell cycle control gene Rb2, mismatch repair gene hMSH2, and signal transduction gene protein kinase C beta2, and increased expression of signal transduction gene MAP kinase, kinase 6. CONCLUSIONS: A new HCC cell line characterized by high pulmonary metastases via s.c. and orthotopic inoculation was established, which provides a new model for the study of liver cancer metastasis. Its gene expression profile could help in the understanding of the mechanism of metastasis and provide potential targets for anti-metastasis intervention.
Animals↗
Human marrow stromal cell therapy for stroke in rat: neurotrophins and functional recovery.
OBJECTIVE: To test the effect of i.v.-injected human bone marrow stromal cells (hMSC) on neurologic functional deficits after stroke in rats. METHODS: Rats were subjected to transient middle cerebral artery occlusion and IV injected with 3 x 10(6) hMSC 1 day after stroke. Functional outcome was measured before and 1, 7, and 14 days after stroke. Mixed lymphocyte reaction and the development of cytotoxic T lymphocytes measured the immune rejection of hMSC. A monoclonal antibody specific to human cellular nuclei (mAb1281) was used to identify hMSC and to measure neural phenotype. ELISA analyzed neurotrophin levels in cerebral tissue from hMSC-treated or nontreated rats. Bromodeoxyuridine injections were used to identify newly formed cells. RESULTS: Significant recovery of function was found in rats treated with hMSC at 14 days compared with control rats with ischemia. Few (1 to 5%) hMSC expressed proteins phenotypic of brain parenchymal cells. Brain-derived neurotrophic factor and nerve growth factor significantly increased, and apoptotic cells significantly decreased in the ischemic boundary zone; significantly more bromodeoxyuridine-reactive cells were detected in the subventricular zone of the ischemic hemisphere of rats treated with hMSC. hMSC induced proliferation of lymphocytes without the induction of cytotoxic T lymphocytes. CONCLUSION: Neurologic benefit resulting from hMSC treatment of stroke in rats may derive from the increase of growth factors in the ischemic tissue, the reduction of apoptosis in the penumbral zone of the lesion, and the proliferation of endogenous cells in the subventricular zone.
Animals↗
Enhancement of pyruvate production by Torulopsis glabrata using a two-stage oxygen supply control strategy.
The effect of agitation speeds on the performance of producing pyruvate by a multi-vitamin auxotrophic yeast, Torulopsis glabrata, was investigated in batch fermentation. High pyruvate yield on glucose (0.797 g g(-1)) was achieved under high agitation speed (700 rpm), but the glucose consumption rate was rather low (1.14 g l(-1) h(-1)). Glucose consumption was enhanced under low agitation speed (500 rpm), but the pyruvate yield on glucose decreased to 0.483 g g(-1). Glycerol production was observed under low agitation speed and decreased with increasing agitation speed. Based on process analysis and carbon flux distribution calculation, a two-stage oxygen supply control strategy was proposed, in which the agitation speed was controlled at 700 rpm in the first 16 h and then switched to 500 rpm. This was experimentally proven to be successful. Relatively high concentration of pyruvate (69.4 g l(-1)), high pyruvate yield on glucose (0.636 g g(-1)), and high glucose consumption rate (1.95 g l(-1)h(-1)) were achieved by applying this strategy. The productivity (1.24 g l(-1) h(-1)) was improved by 36%, 23% and 31%, respectively, compared with fermentations in which agitation speeds were kept constant at 700 rpm, 600 rpm, and 500 rpm. Experimental results indicate that the difference between the performances for producing pyruvate under a favorable state of oxygen supply (dissolved oxygen concentration >50%) was caused by the different regeneration pathways of NADH generated from glycolysis.
Candida↗
Evidence for microbunching "sidebands" in a saturated free-electron laser using coherent optical transition radiation.
We report the first measurements of z-dependent coherent optical transition radiation (COTR) due to electron-beam microbunching at high gains ( >10(4)) including saturation of a self-amplified spontaneous emission free-electron laser (FEL). In these experiments the fundamental wavelength was near 530 nm, and the COTR spectra exhibit the transition from simple spectra to complex spectra ( 5% spectral width) after saturation. The COTR intensity growth and angular distribution data are reported as well as the evidence for transverse spectral dependencies and an "effective" core of the beam being involved in microbunching.
Journal Article↗
Evidence for a central role for electro-osmosis in fluid transport by corneal endothelium.
The mechanism of transepithelial fluid transport remains unclear. The prevailing explanation is that transport of electrolytes across cell membranes results in local concentration gradients and transcellular osmosis. However, when transporting fluid, the corneal endothelium spontaneously generates a locally circulating current of approximately 25 microA cm(-2), and we report here that electrical currents (0 to +/-15 microA cm(-2)) imposed across this layer induce fluid movements linear with the currents. As the imposed currents must be approximately 98% paracellular, the direction of induced fluid movements and the rapidity with which they follow current imposition (rise time < or =3 sec) is consistent with electro-osmosis driven by sodium movement across the paracellular pathway. The value of the coupling coefficient between current and fluid movements found here (2.37 +/- 0.11 microm cm(2) hr(-1) microA (-1), suggests that: 1) the local endothelial current accounts for spontaneous transendothelial fluid transport; 2) the fluid transported becomes isotonically equilibrated. Ca(++)-free solutions or endothelial damage eliminate the coupling, pointing to the cells and particularly their intercellular junctions as a main site of electro-osmosis. The polycation polylysine, which is expected to affect surface charges, reverses the direction of current-induced fluid movements. Fluid transport is proportional to the electrical resistance of the ambient medium. Taken together, the results suggest that electro-osmosis through the intercellular junctions is the primary process in a sequence of events that results in fluid transport across this preparation.
Animals↗
213Bi-PAI2 conjugate selectively induces apoptosis in PC3 metastatic prostate cancer cell line and shows anti-cancer activity in a xenograft animal model.
A novel alpha-particle emitting ((213)Bi) plasminogen activator inhibitor type 2 construct, which targets the membrane-bound urokinase plasminogen activator on prostate cancer cells, was prepared and evaluated in vitro and in a xenograft animal model. The PC3 prostate cancer cell line expresses urokinase plasminogen activator which binds to its receptor on the cell membrane; plasminogen activator inhibitor type 2 is bound to urokinase plasminogen activator/urokinase plasminogen activator receptor to form stable complexes. In vitro, the cytotoxicity of (213)Bi-plasminogen activator inhibitor type 2 against prostate cancer cells was tested using the MTS assay and apoptosis was documented using terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labelling (TUNEL) assay. In vivo, antiproliferative effects for tumours and prostate cancer lymph node metastasis were carried out in an athymic nude mouse model with a subcutaneous xenograft of PC3 cells. (213)Bi-plasminogen activator inhibitor type 2 was specifically cytotoxic to PC3 cells in a concentration-dependent fashion, causing the cells to undergo apoptosis. A single local or i.p. injection of (213)Bi-plasminogen activator inhibitor type 2 was able to completely regress the growth of tumours and lymph node metastases 2 days post subcutaneous inoculation, and obvious tumour regression was achieved in the therapy groups compared with control groups with (213)Bi-plasminogen activator inhibitor type 2 when the tumours measured 30-40 mm(3) and 85-100 mm(3). All control animals and one of five (20%) mice treated with 3 mCi kg(-1) (213)Bi-plasminogen activator inhibitor type 2 developed metastases in the lymph nodes while no lymphatic spread of cancer was found in the 6 mCi kg(-1) treated groups at 2 days and 2 weeks post-cell inoculation. These results demonstrate that this novel (213)Bi-plasminogen activator inhibitor type 2 conjugate selectively targets prostate cancer in vitro and in vivo, and could be considered for further development for the therapy of prostate cancer, especially for the control of micro-metastases or in minimal residual disease.
Animals↗
Genome organization of Casphalia extranea densovirus, a new iteravirus.
The viral genome of Casphalia extranea densovirus (CeDNV) has been cloned and sequenced. It was 5002 nucleotides long and contained inverted terminal repeats of 230 nucleotides. Their distal 159 nucleotides formed imperfect palindromes in two orientations. Three large open reading frames (ORFs) were identified on the same strand, two in the left-hand half and one in the right-hand half. Each of the five structural proteins, expressed from the right-hand ORF in the baculovirus system, autoassembled into capsids. The two left-hand ORFs overlapped and code for nonstructural (NS) proteins. NS1 protein was shown to contain replicator protein and helicase/ATPase motifs. The PGY region in VP1 capsid protein is conserved among most parvoviruses and contained a phospholipase A(2) motif, a novel viral enzyme. This domain was expressed and its enzyme activity was demonstrated. The approximate 75% sequence identity between the DNAs from CeDNV and BmDNV-1 and identical genome organization indicated that CeDNV should be classified in the Iteravirus genus.
Amino Acid Sequence↗
Rapid pathotyping of Newcastle disease virus using a single-chain Fv displayed on phage against the C-terminal end of the F2 polypeptide.
Filamentous bacteriophage display technology has been used to generate specific antibody fragments for differentiating virulent and avirulent Newcastle disease virus. A single-chain Fv fragment to the motif (112)RRQ(114), present at the F2 C-terminal end of many virulent Newcastle disease virus isolates, was isolated from a phage display library derived from a rabbit immunized with a peptide conjugate. An ELISA evaluation was carried out to test its ability to differentiate between 11 avirulent and 34 virulent NDV isolates. The antibody fragment reacted with 25/28 virulent viruses with the putative motif (112)RRQ(114). The three exceptions were viruses with an arginine instead of glycine, at position 110 of the fusion protein, just preceding the cleavage site. Five of six virulent isolates, whose predicted motif was different from that usually found in virulent strains, also tested negative. However, the antibody did react with one isolate with the motif (112)KRQ(114). There was no apparent reactivity with any of the avirulent isolates tested. We conclude that this antibody may, in the future, be a useful aid for the pathotyping of NDV isolates.
Amino Acid Motifs↗
Genetic characterization of the oral Actinomyces.
Actinomyces are difficult to identify using serological and biochemical methods but genotyping is an efficient and reliable means of bacterial characterization and can be used to determine clonal identity. The purpose here was to genotype 13 American type culture collection (ATCC) reference strains representing six different oral Actinomyces spp. by using chromosomal DNA fingerprinting (CDF), arbitrarily primed-polymerase chain reaction (AP-PCR) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). In CDF analysis, BamHI, BstEII and SmaI yielded digestion patterns revealing characteristic differences among the known Actinomyces spp., with SmaI demonstrating optimal resolution. Amplicons generated by AP-PCR with primer OPB-07 displayed banding patterns that permitted discrimination of all Actinomyces strains tested. PCR-RFLP with MnlI digests generated fragment patterns that also characterized the reference strains. Collectively, genotypic profiles generated by CDF, AP-PCR and PCR-RFLP permitted differentiation of all 13 ATCC Actinomyces strains. SmaI CDF analysis of 18 clinical isolates of catalase-positive A. naeslundii genospecies 2 revealed extensive genetic diversity among these strains. These molecular approaches may be useful in determining genetic diversity within oral Actinomyces populations and fidelity of Actinomyces transmission between mother and child.
Actinomyces↗
Beneficial hemodynamic effects of autologous bone marrow cell transplantation in rats with heart failure.
Explore the source record for details and available documents.
Animals↗
Postsynaptic GABAB receptors in supraoptic oxytocin and vasopressin neurons.
Explore the source record for details and available documents.
Animals↗
How do transplanted olfactory ensheathing cells restore function?
In this article, we review our work on regeneration of the corticospinal tract in rats following a lesion at upper cervical level. We outline the rationale for using olfactory ensheathing cells, and summarize the evidence for regeneration and functional recovery. The present interpretation on the mechanisms of functional recovery is partly hypothetical, and we emphasize where further experimental evidence is needed.
Animals↗
Exposure of Japanese medaka (Oryzias latipes) to benzo[a]pyrene suppresses immune function and host resistance against bacterial challenge.
Besides being a potent chemical carcinogen, benzo[a]pyrene (BaP) has also been shown to suppress the immune response of mammals. However, even though BaP is a ubiquitous environmental contaminant to which aquatic species may be directly exposed, information regarding the effects of BaP on the immune system of fish is still lacking. Therefore, laboratory studies were conducted using Japanese medaka (Oryzias latipes) to examine the effects of BaP on host immune status. A single IP injection of BaP at 2, 20 or 200 microg/g BW had no effect upon medaka survival or condition factors for up to 7 days post-injection. Forty-eight hours after injection of either BaP or the vehicle control, fish were sacrificed and the appropriate organs/cells used to assess effects upon: splenic lymphocyte proliferation; kidney phagocyte intracellular superoxide (*O(2)(-)) production; and, CYP1A protein level/activity. In separate experiments, fish were injected with either sheep red blood cells or the bacterial pathogen Yersinia ruckeri at 48 h post-BaP exposure for later determination of antibody-forming cell (AFC) numbers and bacterial host resistance, respectively. Results demonstrated that in the absence of effects upon host survival or condition factors, a single exposure to a relatively low dose of BaP (2 microg/g BW) significantly suppressed mitogen-stimulated T- and B-lymphocyte proliferation (in the absence of elevated hepatic CYP1A expression/activity). At higher concentrations, BaP also reduced AFC numbers, phagocyte-mediated *O(2)(-) production, and host resistance against bacterial infection. These results clearly demonstrate the ability of BaP to compromise the immune response of fish and indicate the utility of the fish immune response to serve as an early indicator of BaP exposure/effects in exposed feral populations.
Animals↗
Patterns of lung function in asymptomatic nonsmoking men and women in the People's Republic of China.
PURPOSE: To evaluate patterns of lung function in healthy, working Chinese men and women in different geographic areas of the People's Republic of China (PRC). METHODS: We conducted lung function tests on 2926 asymptomatic, never smoking Chinese men and women aged 35-56 years residing in or around Beijing and Guangzhou. Within each of these locations, separate urban and rural samples were recruited. RESULTS: Age and height adjusted lung function was greater in Beijing than in Guangzhou, and within each city for residents of rural vs. urban areas. Among women, estimated rates of lung aging were greater in Beijing than in Guangzhou, and in urban vs. rural areas. Both FEV(1) and FVC exhibited a curvilinear association with body mass index. CONCLUSIONS: Lung function data from this largely working cohort exhibited marked geographic and urban-rural differences in this never smoking, adult Chinese cohort. Such variation is not uncommon and may reflect differences in body size, diet, and environmental and occupational exposures across these different settings. Caution should be used in applying published reference equations to populations from different parts of the PRC.
Adult↗