Biomedical subjects

W Ji

Publications and source records attributed to W Ji.

67 records · Page 4Linked to original sources

PubMed1997

[Transfer and expression of antisense genes of hepatitis B virus (HBV) and their anti-HBV effects].

OBJECTIVE: To observe the transfer and expression of HBV antisense genes and their anti-HBV effects in 2.2.15 cells mediated by retroviral vector-packaging cell line system. METHODS: The recombinant retroviral vectors mediating expression of HBV antisense RNA complementary to 1402-2906 fragment (preC/C) or 2839-1986 fragment (preS/S) of HBV DNA were used to transduce into NIH 3T3 cells and 2.2.15, respectively. Then, the total RNAs of tranduced NIH 3T3 cells were extracted and hybridized with HBV DNA probe. The HBsAg and HBeAg in the supernatants of cultured 2.2.15 cells were assayed with RIA method and the DNAs were hybridized with HBV DNA probe by dot blot. RESULTS: The results showed that the HBV antisense genes could be transfered into and expressed in the NIH 3T3 cells mediated by recombinant retroviral vector packaging cell line (PA317 cell). The inhibitory effects on the expression of HBV antigens by antisense RNAs appeared as early as on the day 3 after transduced, reached peak level on the day 5, and persisted at least for eleven days. The inhibitory rates of HBsAg and HBeAg were 71% and 23% by antisense preS/S, and 23% and 59% by antisense preC/C on the day 5 after transduction. In comparison to blank control or sense--gene expressing vectors, the inhibitory effects of HBV antisense vectors were highly significant (P < 0.01). HBV DNA level in the supernatant of the 2.2.15 cells transduced with either antisense preS/S or preC/C in comparison to the blank control vectors was also reduced on the day 5 after transduction as detected by DNA dot blot assays, but the viability of transduced 2.2.15 cells was not affected as detected by MTT assays. CONCLUSIONS: HBV antisense genes can be transfered and expressed in the eukaryotic cells and the expression of HBV antisense RNAs in 2.2.15 cells can inhibit the replication and expression of HBV.

3T3 Cells↗

PubMed1995

Frequent detection of bcl-2/JH translocations in human blood and organ samples by a quantitative polymerase chain reaction assay.

Using an ultrasensitive assay involving the PCR, we have examined the frequency of a follicular lymphoma-associated translocation in peripheral blood from 132 individuals, most of whom were healthy blood donors. This translocation occurs between the bcl-2 proto-oncogene and the JH gene region and prolongs the life of lymphocytes. At a level of sensitivity of 1 translocation-bearing cell per 5 x 10(6) cells, almost one-half of healthy human adults had this translocation in the mononuclear fraction of peripheral blood. However, the range of frequency of these translocations spanned almost three orders of magnitude among translocation-positive individuals. Furthermore, there was a statistically significant increase with age in the percentage of individuals who were translocation positive. Such an age correlation was also seen for the percentage of blood donors with rather high translocation frequencies (> or = 20 per 5 x 10(6) peripheral blood mononuclear cells). However, the blood donor who had by far the highest concentration of this translocation was a healthy 35-year-old male containing approximately 900 apparently monoclonal, translocation-bearing cells per 5 x 10(6) peripheral blood mononuclear cells. Our findings suggest that some individuals who may be at risk for follicular lymphoma might be able to be identified by this PCR assay on peripheral blood. Also, these data may help explain the age dependence of the occurrence of this cancer.

Adolescent↗

PubMed1995

Reporter gene expression upon stable transfection when only a TATA box or a TATA box plus Sp1 sites are present 5' to the gene.

Episomal plasmids for stable transfection of mammalian cell cultures were constructed that have a G418-resistance (neo) gene immediately downstream of a highly truncated promoter. These plasmids had a function hygromycin-resistance gene (hyg) as a selectable marker. Surprisingly, in LTK- cells, but not HeLa cells, stably transfected with these BK virus-based plasmids having no promoter elements adjacent to the neo gene, readthrough transcription, probably from about 1 kb upstream, gave almost as efficient expression of the neo gene as of the hyg gene with a full-length promoter immediately upstream. When the transfecting plasmids contained Epstein-Barr virus (EBV) DNA sequences for episomal maintenance and had multiple Sp1 sites and a TATA box as the only promoter elements 5' to the neo gene, only about 3-9% of HeLa transfectants were G418 resistant (G418R). In transfections with analogous plasmids lacking these promoter elements 5' to the neo gene, no G418R colonies were seen. The establishment of the G418R phenotype probably required integration of plasmid DNA into favorable chromosomal sites and was aided by the presence of the TATA box plus Sp1 sites as a subminimal promoter. The absence of detectable G418-resistance in most of the HeLa transfectant clones obtained with EBV-type plasmids, even at a high plasmid copy number and even when a TATA box and six Sp1 sites were present immediately upstream of the neo gene, indicates that these elements do not suffice for appreciable gene expression in vivo and that this is a suitable model system for studying DNA rearrangements that can potentiate expression of the neo gene.

Animals↗

PubMed1995

Screening method for cellulose biosynthesis inhibitors with herbicidal activity.

A new screening method for inhibitors of cellulose biosynthesis is described. This method utilized three microbial strains; a cellulose-containing fungus Phytophthora, and a cellulose non-containing fungus Candida, and a bacterial strain of Acetobacter, a cellulose-producing acetic acid bacterium. The primary screen examined microbial cultures for selective growth inhibition against Phytophthora with no inhibition against Candida. The secondary screen tested for herbicidal activity. Thirdly, the active cultures were examined for their inhibition of cellulose biosynthesis by an Acetobacter strain. A screening trial with this new method led to the discovery of two microbial metabolites named phthoxazolin A and phthoramycin as new inhibitors of cellulose biosynthesis with herbicidal activity.

Acetobacter↗

PubMed1994

Effect of internal direct and inverted Alu repeat sequences on PCR.

We have studied the effect of repeated DNA sequence, especially Alu repeats, on PCR. Alu repeats are sequences that are approximately 300 bp long and interspersed at a very high copy number throughout the human genome. We amplified part of the human low-density lipoprotein receptor gene containing two Alu repeat sequences in the same orientation, approximately 7.8 kb apart, with unique sequence primers outside these repeats. The major PCR product was a DNA fragment with an in vitro deletion between the Alu repeats. The formation of this product depended on the template concentration and the type of polymerase used. Such a product arose apparently as a result of a "jumping reaction" involving a primer whose extension was terminated prematurely within one Alu repeated followed by annealing of such an incompletely extended primer to the other, distant Alu repeat. No such jumping products were seen when a 0.8-kb region containing two nearby inverted Alu repeats within the human alpha-galactosidase A gene was subject to PCR with unique sequence primers annealing just outside these repeats.

Animals↗

PubMed1994

[Several blood group antigens expressions in laryngeal cancer tissue and their clinical significance].

In this study we used the method of immunohistochemistry (ABC method) to examine antigen A, B, H and T expression in laryngeal cancer tissue and their clinical significance. Results showed that disappearance of antigen A, B, H was related to patient's prognosis and cancer cell differentiation. Antigen T revealed powerful expression in patients with cervical lymph node metastases. This index can help diagnosing subclinical metastases of the cervical lymph node.

ABO Blood-Group System↗

PubMed1993

Observation of therapeutic effect in 50 cases of chronic renal failure treated with rhubarb and adjuvant drugs.

Treatment of chronic renal failure with rhubarb and adjuvant drugs combined with other appropriate measures alleviates the suffering of the patients and improves the quality of their survival. Most patients can take care of themselves after treatment, and some can engage in half-day work. The treatment prolongs the life of the patient, and reduces medical expenses. It is of definite social and economic benefit, and conforms with China's conditions. Except for very severe cases whose blood creatinine exceeds 884 mumol/L, it can be given to all patients. It can also be used as a transitional measure before more radical therapies may be instituted.

Adolescent↗

PubMedDate not supplied

Serum-free culture of rhesus monkey embryonic stem cells.

Previous studies have shown that the maintenance and proliferation of undifferentiated rhesus monkey embryonic stem (rES) cells requires medium supplemented with fetal bovine serum (FBS). Due to the uncharacterized composition and variation in serum nature, the present study aimed to replace the serum-containing medium with a serum-free medium in the rES cell culture. The results showed that after the initial 48-h culture in the routinely used serum-containing medium, rES cells can grow and proliferate for a prolonged period in the serum-free medium composed of DMEM supplemented with a cocktail of BSA, IGF-1, TGF-alpha, bFGF, aFGF, estradiol, and progesterone. rES cells cultured in the serum-free medium maintained high level of alkaline phosphatase activity and OCT4 level. There was no indication of differentiation as judged by the marker gene expression of all three embryonic germ layers and trophoblast. In addition, serum-free culture would not affect the passage capacity and differentiation potential of rES cells. This work will facilitate the future study of induced differentiation of rES cells and other applications.

Alkaline Phosphatase↗

PubMedDate not supplied

Single UV excitation of Hoechst 33342 and propidium iodide for viability assessment of rhesus monkey spermatozoa using flow cytometry.

Many fluorescent probes excited by visible light have been used to assess sperm quality by flow cytometry. Developing a viability evaluation method using UV excited stains would be useful for multiparameter analysis of sperm function. This investigation was conducted to determine the efficacy of Hoechst 33342 (H342) and propidium iodide (PI) dual staining for evaluating rhesus monkey sperm viability through use of flow cytometry and excited by a single UV laser. The results showed that the live cells stained only with H342 strongly correlated with expected sperm viability, and flow cytometric analyses were highly correlated with fluorescence microscopic observation. Using H342/PI/SYBR-14 triple staining method, it was found that the live/dead sperm distributions were completely concordant in both H342/PI and SYBR-14/PI assays. In addition, this dual staining was extended with fluorescein isothiocyanate-conjugated peanut agglutinin (FITC-PNA) to simultaneously analyze viability and acrosome integrity of sperm cryopreserved using two different extenders, TTE and TEST, and indicated that TTE offered better preservation of plasma and acrosome integrity than TEST. Therefore, the H342/PI dual staining provides an accurate technique for evaluating viability of rhesus monkey sperm and should be valuable for multiparameter flow cytometric analysis of sperm function.

Animals↗

PubMedDate not supplied

Synthesis and biological evaluation of boronated nucleosides for boron neutron capture therapy (BNCT) of cancer.

Several N-3 substituted carboranyl Thd analogs were synthesized. These agents as well as some non-boronated nucleosides were evaluated in phosphoryl transfer assays with recombinant human TK1 and TK2. For some carboranyl thymidine analogs, TK1 phosphorylation rates approached 38% that of thymidine. Their in vitro cytotoxicty appeared to correlate with the TK1 levels in the tested cells. In some cases increased uptake in tumor cell nuclei compared with the surrounding cytoplasm was detected in vitro.

Boron Compounds↗

PubMedDate not supplied

Seasonal home range changes of the Sichuan snub-nosed monkey (Rhinopithecus roxellana) in the Qinling Mountains of China.

The seasonal changes in home range and habitat use of the Sichuan snub-nosed monkey, Rhinopithecus roxellana, have been studied by radio tracking and direct observation in the Qinling Mountains of China. The home range size was 14.1 km(2) in spring, 9.5 km(2) in summer, 12.1 km(2) in autumn and 12.3 km(2) in winter; the total area used was 22.5 km(2). The area of the home range is closely correlated with the distribution and abundance of food resources. Seasonal change in the home range area is correlated with the phenology of the vegetation. An unusually large home range is a unique characteristic of this monkey.

Animals↗

PubMedDate not supplied

Optic, olfactory, and vestibular dysmorphogenesis in the homozygous mouse insertional mutant Tg9257.

The transgene insertional mutation 9257 on mouse chromosome 18 was originally identified by the circling behavior caused by vestibular abnormalities in heterozygous mutants. To characterize the homozygous phenotype, we generated F2 offspring from the cross (C57BL/6J-tg/+ x DBA/2J). Eye defects ranging in severity from microphthalmia to anophthalmia were observed in the tg/tg offspring. Dysmorphic development of the lens was evident as early as E10.5 in homozygous transgenic mice. Apparent agenesis of the lateral semicircular canal was evident at E14.5. Anomalies of nasomaxillary structures and olfactory neuroepithelium were present in heterozygous and homozygous transgenic mice. The 9257 mutation provides a model for analysis of the morphogenesis of these three neurosensory systems and their associated bony structures.

Abnormalities, Multiple↗

PubMedDate not supplied

Comparative in vitro evaluation of dequalinium B, a new boron carrier for neutron capture therapy (NCT).

A boronated derivative of dequalinium, a delocalized lipophilic cation (DLC), was synthesized as a potential boron carrier for the selective targeting of mitochondria in malignant versus benign cells for boron neutron capture therapy (BNCT), a binary modality for the treatment of cancer. This agent, designated DEQ-B, was taken up and retained in vitro in the KB, F98, and C6 tumor cell lines but not in the normal epithelial cell line CV1. DEQ-B was also less toxic in the latter cell line at lower exposure concentrations The uptake, retention, and toxicity profiles of DEQ-B are comparable to those of the non-boronated DLCs, dequalinium, MKT 077, RH 123, and tetraphenylphosphonium chloride. Our results suggest that the synthesis and further evaluation of boronated DLCs as potential delivery agents for BNCT is warranted.

Animals↗