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Biomedical subjects

J Yu

Publications and source records attributed to J Yu.

At least 109 records · Page 6Linked to original sources
PubMed2001

[Effects of hepatitis G virus coinfection on hepatic pathological changes of patients with chronic hepatitis B: a long-term comparative study].

OBJECTIVE: To observe the long-term effect of hepatitis G virus (HGV) coinfection on hepatic pathological changes of patients with chronic hepatitis B (CHB) and explore the pathogenicity of HGV. METHODS: Menghini method liver biopsy was performed on 45 patients with CHB twice with an interval of 5 years on a voluntary basis. The liver tissue of 21 cases was HGV nonstructural region 5 (HGV NS5) antigen positive by peroxidase anti-peroxidase (PAP) immunohistochemical staining assay (HGV coinfection group) in these two tests, and 24 cases were negative (HGV noncoinfection group). There was no significant difference in age, sex, course of disease, amount of serum HBV-DNA by competitive quantitative polymerase chain reaction assay and severity of hepatic pathological leisions between these two groups (P < 0.05) and they were treated with the same scheme and without sustained curative effeect. The hepatic pathological changes of the two groups after 5 years were compared and analysed retrospectively. RESULTS: There was no significant difference in basic hepatic pathological change, severity of inflammatory activity grade and fibrosis stage in these two groups. The numbers of cases of inflammatory activity grade G1, G2, G3, and G4 were 3, 7, 7, and 4 in HGV coinfection group, and 5, 8, 7, and 4 in HGV noncoinfection group in the beginning of observation; and were 3, 5, 7, and 6 in HGV coinfection group, and 4, 6, 8, and 6 in HGV noncoinfection group after 5 years. The numbers of cases in fibrosis stages S1, S2, S3, and S4 were 4, 7, 7, and 3 in HGV coinfection group, and 6, 8, 6, and 4 HGV noncoinfection group in the beginning of observation; and were 3, 6, 5, 7 in HGV coinfection group, and 4, 7, 5, and 8 in HGV noncoinfection group after 5 years (P > 0.05). CONCLUSION: HGV coinfection does not lead to the activation of hepatic pathological changes and does not speed up the progression of fibrosis in patients with CHB. HGV coinfection does not play an obvious role in long-term hepatic pathological changes of patients with CHB. HGV has at most a mild hepatic pathogenicity.

Adult↗
PubMed2001

A simulation study on the topotactic transformations from aluminophosphate AlPO(4)-21 to AlPO(4)-25.

Aluminophosphate AlPO(4)-21 (AWO), formulated /(CH(3))(2)NH(2)/[Al(3)P(3)O(12)(OH)], has been synthesized solvothermally by using dimethylamine as the template. Single-crystal X-ray diffraction analysis shows that AlPO(4)-21 crystallizes in the monoclinic space group P2(1)/n with a = 8.687(2) A, b = 17.428(5) A, c = 9.159(2) A, beta = 109.60(2) degrees, V = 1306.3(5) A(3), and Z = 4. XRD analysis shows that AlPO(4)-21 transforms to AlPO(4)-25 (ATV) upon calcination at 500 degrees C. The molecular dynamics simulation approach was used to investigate the topotactic transformations from AlPO(4)-21. The simulation study suggests that AlPO(4)-21 is energetically favored to transform to AlPO(4)-25, as well as other hypothetical forms, by the changing of the UUDD chains to the UDUD chains.

Journal Article↗
PubMed2001

Dose-dependent and independent temporal patterns of gene responses to ionizing radiation in normal and tumor cells and tumor xenografts.

U87 cells derived from human malignant gliomas and growtharrested human embryonic lung (HEL) fibroblasts were examined with respect to their response to ionizing radiation by profiling their RNAs. In the first series of experiments, cells grown in vitro were harvested and the RNAs were extracted 5 h after exposure to 1, 3, or 10 Gy. In the second series of experiments the U87 tumors were implanted in nude mice and subjected to the same doses of irradiation. The xenografts were harvested at 1, 5, or 24 h after irradiation and subjected to the same analyses. We observed and report on (i) cell-type common and cell-type specific responses, (ii) genes induced at low levels of irradiation but not at higher doses, (iii) temporal patterns of gene response in U87 xenografts that varied depending on radiation dose and temporal patterns of response that were similar at all doses tested, (iv) significantly higher up-regulation of cells in xenografts than in in vitro cultures, and (v) genes highly up-regulated by radiation. The responding genes could be grouped into nine functional clusters. The representation of the nine clusters was to some extent dependent on dose and time after irradiation. The results suggest that clinical outcome of ionizing radiation treatment may benefit significantly by taking into account both cell-type and radiation-dose specificity of cellular responses.

Animals↗
PubMed2001

Influence of the yihE gene of Shigella flexneri on global gene expression: on analysis using DNA arrays.

Inactivation of dsbA (disulfide bond formation), either by an insertion (Sh4, dsbA::kan) or by alteration of the active site (Sh42, dsbA33G), renders Shigella flexneri avirulent. However, Sh4 and Sh42 behave differently in many ways in vitro and in vivo. A gene of unknown function, yihE, up-stream and cotranscribed with dsbA, is thought to differentiate Sh4 and Sh42 as the kan insertion may result in a truncated unstable yihE-dsbA mRNA in Sh4. To gain insight into the function of yihE, DNA array hybridization was performed to study the genomic expression in Sh4, Sh42, and a newly constructed yihE mutant (Sh54). Compared to the wild-type, M90TS, Sh4, and Sh54 demonstrated significantly changed transcription levels of about 100 genes, of which many involved in energy metabolism and stress response were down- and up-regulated, respectively. In contrast, Sh42 showed altered transcription levels of only 20 genes. The results argue that yihE is principally responsible for the changed genomic expression in Sh4 and Sh54. Given the fact that the transcription of yihE-dsbA is regulated by the CpxRA two-component signal transduction system, yihE is probably involved in the extracytoplasmic stress response in a manor deserving further studies.

Bacterial Proteins↗
PubMed2001

Inactivation of DsbA alters the behaviour of Shigella flexneri towards murine and human-derived macrophage-like cells.

The mutants of Shigella flexneri, Sh4 (dsbA::kan) and Sh42 (dsbA33G), behave differently towards murine and human-derived macrophage-like cells in vitro. Sh4 was trapped in the phagocytic vacuoles of the murine J774 cells as evidenced by its colony forming units plus and minus chloroquine exposure in a gentamicin protection assay, and by light and transmission electron microscopy (TEM). Sh42, similar to the wild-type M90TS, was able to escape from the vacuoles and kill host cells presumably by inducing apoptosis. In U937 cells, unlike M90TS that was free in the cytosol, both Sh4 and Sh42 grew poorly. TEM revealed that Sh4 and Sh42 were trapped within the U937 phagocytic vacuoles. Furthermore, the two mutants induced different patterns of interleukin-1beta and tumour necrosis factor-alpha expression, which might explain why they possess different immunogenic properties in vivo.

Animals↗
PubMed2001

Chromosome 16 loss of heterozygosity in tuberous sclerosis and sporadic lymphangiomyomatosis.

In previous work we found loss of heterozygosity (LOH) of the wild-type TSC2 allele in the abnormal pulmonary smooth muscle cells and renal angiomyolipoma cells from patients with sporadic pulmonary lymphangiomyomatosis (LAM). Here we report TSC2 LOH in microdissected pulmonary LAM cells from a patient with tuberous sclerosis complex (TSC), demonstrating for the first time that the two-hit tumor suppressor gene model applies to the TSC-associated, as well as sporadic LAM. We also compared the chromosome 16 LOH region between angiomyolipoma and pulmonary LAM from two patients with sporadic LAM. Previously we found that these patients had TSC2 mutations and TSC2 LOH in their angiomyolipomas and pulmonary LAM cells but not in normal lung or kidney cells. This suggests that pulmonary LAM may result from the migration of smooth muscle cells from renal angiomyolipomas to the lung. In this case, one would predict that the angiomyolipoma and LAM cells would have identical LOH patterns. We found that at each chromosome 16 marker, the results were concordant between angiomyolipoma and LAM. This is consistent with a model in which pulmonary LAM cells and angiomyolipoma cells have a common genetic origin.

Chromosomes, Human, Pair 16↗
PubMed2001

Retraction.

Explore the source record for details and available documents.

Retraction Notice↗
PubMed2001

Thioredoxin expression in primary T-cell acute lymphoblastic leukemia and its therapeutic implication.

Increased expression of intracellular thioredoxin has been implicated in the inhibition of apoptosis and in a decrease in the sensitivity of the malignancies to drug-induced apoptosis. In the present studies, we analyzed expression of thioredoxin in samples from 28 children with T-cell acute lymphoblastic leukemia and analyzed their sensitivity toward inhibition of thioredoxin expression. Thioredoxin was expressed in variable amounts. Higher expression was associated with higher WBC counts. Exogenously added thioredoxin stimulated proliferation of clonogenic cells among the T-cell acute lymphoblastic leukemia samples expressing relatively lower levels of intracellular thioredoxin, whereas there was no effect on the clonogenic cells expressing high levels of thioredoxin. In addition, there was differential sensitivity of the leukemia clonogenic cells toward 1-methylpropyl 2-imidazolyl disulfide, an inhibitor of thioredoxin expression, as compared with normal hematopoietic progenitors. This suggests the possibility of using this approach for treatment. Because overexpression of thioredoxin is associated with resistance to many anticancer drugs, the inhibition of thioredoxin expression may overcome this drug resistance and probably sensitize leukemia cells to other chemotherapeutic agents.

Antineoplastic Agents↗
PubMed2001

Structure-activity studies of antitumor agent irofulven (hydroxymethylacylfulvene) and analogues.

Many analogues of the antitumor agent irofulven have been readily prepared by replacing the allylic hydroxyl with a variety of nucleophiles. Analogues of acylfulvene (the precursor to irofulven) were also prepared by Michael reaction with acrolein. The toxicity of the analogues was determined, as well as preclinical antitumor activity. Several analogues exhibited good activity in mouse xenografts. Structural requirements for activity are discussed.

Animals↗
PubMed2001

Use of the probasin promoter ARR2PB to express Bax in androgen receptor-positive prostate cancer cells.

BACKGROUND: Adenovirus-mediated overexpression of the apoptosis-inducing protein Bax can induce apoptosis in prostate cancer cell lines. Constitutive overexpression of Bax could result in unwanted apoptosis in every site of accidental Bax accumulation in vivo. Therefore, we developed an adenoviral construct (Av-ARR2PB-Bax) in which the probasin promoter, modified to contain two androgen response elements, drives Bax expression. This promoter would be expected to limit expression of Bax to cells expressing the androgen receptor. METHODS: A variety of androgen receptor (AR)-positive and -negative cell lines of prostatic or nonprostatic origin were infected with Av-ARR2PB-Bax or a control virus, Av-ARR2PB-CAT, in which the same promoter drives expression of the chloramphenicol acetyl transferase-reporter gene. Bax expression and apoptosis in vitro were assessed by western blot analysis. Tumor size and apoptosis in vivo were assessed after four weekly injections of Av-ARR2PB-Bax or Av-ARR2PB-CAT into subcutaneous LNCaP xenografts growing in uncastrated male mice. All statistical tests were two-sided. RESULTS: Bax was overexpressed in an androgen-dependent way in AR-positive cell lines of prostatic origin but not in AR-positive cells of nonprostatic origin or in AR-negative cell lines of either prostatic or nonprostatic origin. The androgen dihydrotestosterone activated apoptosis in LNCaP cells infected with Av-ARR2PB-Bax but not in those infected with Av-ARR2PB-CAT. Av-ARR2PB-Bax-injected LNCaP xenograft tumors decreased in tumor size from 34.1 mm3 (95% confidence interval [CI] = 25.1 mm3 to 43.1 mm3) to 24.6 mm3 (95% CI = -2.5 mm3 to 51.7 mm3), but the difference was not statistically significant (P =.5). Tumors injected with Av-ARR2PB-CAT increased in size, from 28.9 mm3 (95% CI = 12.7 mm3 to 45.1 mm3) to 206 mm3 (95% CI = 122 mm3 to 290 mm3) (P =.002) and contained statistically significant more apoptotic cells (23.3% [95% CI = 21.1% to 25.6%] versus 9.5% [95% CI = 8.0% to 11.1]) (P<.001). CONCLUSIONS: Av-ARR2PB-Bax induces androgen-dependent therapeutic apoptosis in vitro and in vivo by activating apoptosis in AR-positive cells derived specifically from prostatic epithelium and does not affect nonprostatic cells.

Adenoviridae↗
PubMed2001

Sequence analysis of the Spodoptera litura multicapsid nucleopolyhedrovirus genome.

The complete Spodoptera litura multicapsid nucleopolyhedrovirus (SpltMNPV) genome contained 139,342 bp with a G+C content of 42.7%, and 141 putative open reading frames (ORFs) or genes of 150 nucleotides or greater that showed minimal overlap. Ninety-six ORFs had homologues in Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV), 16 had homologues in other baculoviruses, and 29 were unique to SpltMNPV. The homologues of ubiquitin and gp37 are fused in SpltMNPV. The genome lacked a homologue of the major budded virus glycoprotein gene gp64, but it contained a homologue of ORF130 of Lymantria dispar multicapsid nucleopolyhedrovirus (LdMNPV). There were two homologues of AcMNPV ORF2 (bro gene), and a DnaJ protein gene (SpltORF39) in which the N-terminus showed homologies with the J domain of DnaJ family proteins. Seventeen homologous regions (hrs) were identified, each containing 2-29 palindromic repeats, with an average length of 534 bp and base content (G+C%) of 33.0.

Amino Acid Sequence↗
PubMed2001

A dynamic study and modeling of the formation of polyhydroxyalkanoates combined with treatment of high strength wastewater.

Production of biodegradable thermoplastics, polyhydroxyalkanoates (PHAs), from organic wastes may provide multiple benefits to environmental conservation efforts. In this study, microfiltration-coupled reactors were set up to study the dynamic behavior of a typical PHA-producing bacteria, Ralstonia eutropha, fed with a real acidic solution from starch acidogenesis in a continuous flow system. The majorfermentation acids (butyric and acetic acids) were utilized by the PHA producers at a high conversion rate (>95%) when the cells were suspended in a small volume of mineral solution (pH 7), but at a low conversion rate (<10%) when the cells were suspended in an acidic solution (pH 4). The acids were consumed mainly for PHA synthesis and maintenance energy, which resulted in slow growth of PHA-producing cells and a washout of the cells in the continuous flow system. PHAs, however, were continuously synthesized and accumulated during the washout. A simple dynamic model is proposed for estimation of specific growth rates and PHA formation rates during the washout at two hydraulic retention times (HRT) or dilution rates. The net specific growth rate of PHA-producing cells was near zero at a hydraulic retention time (HRT) of around 30 h, but it increased to 0.01 h(-1) when the HRT was reduced to 18 h. The model also reveals that PHA was synthesized faster based on the active biomass (ABM) during the short HRT (10.3 mg PHA/g ABM.h) than during the long HRT (3.4 mg PHA/g ABM.h).

Biodegradation, Environmental↗
PubMed2001

Search for the lepton family number violating process nu(mu)e(-) --> mu(-)nu(e).

The NuTeV experiment at Fermilab has used a sign-selected neutrino beam to perform a search for the lepton number violating process nu(mu)e(-)-->mu(-)nu(e), and to measure the cross section of the standard model inverse muon decay process nu(mu)e(-)-->mu(-)nu(e). NuTeV measures the inverse muon decay asymptotic cross-section slope sigma/E to be (13.8 +/- 1.2 +/- 1.4) x 10(-42) cm(2)/GeV. The experiment also observes no evidence for lepton number violation and places one of the most restrictive limits on the cross-section ratio sigma(nu(mu)e(-)-->mu(-)nu(e))/sigma(nu(mu)e(-)-->mu(-)nu(e)) < or = 1.7% at 90% C.L. for V-A couplings and < or = 0.6% for scalar couplings.

Journal Article↗
PubMed2001

Molecular cloning and characterization of a novel calcium/calmodulin-dependent protein kinase II inhibitor from human dendritic cells.

Calcium/calmodulin-dependent protein kinase II (CaMKII) is a widely distributed protein kinase that regulates numerous physiological functions. Inhibitors of CaMKII are useful tools for investigating the CaMKII functions. Here we identified a novel CaMKII inhibitor protein (CaM-KIIN) from the human dendritic cell cDNA library by large-scale random sequencing. Human CaM-KIIN contains 79 amino acids, which shares 98% identity and 98% positives with rat CaMKII inhibitor protein beta and 65% identity and 78% positives with rat CaMKII inhibitor alpha. Human CaM-KIIN mRNA expression was detectable in various tissues and cell lines by Northern blot and RT-PCR. To investigate its biological functions, full-length human CaM-KIIN was overexpressed in colon adenocarcinoma LoVo cells. When expressed in LoVo cells, it could inhibit cell proliferation, block cell growth, and decrease the viable cell number. These results characterize a potential cellular inhibitor protein of CaMKII that plays an important role in the regulation of cell growth.

Adenocarcinoma↗
PubMed2001

Observation of an anomalous number of dimuon events in a high energy neutrino beam.

A search for long-lived neutral particles ( N0's) with masses above 2.2 GeV/c(2) that decay into at least one muon has been performed using an instrumented decay channel at the NuTeV experiment at Fermilab. Data were examined for particles decaying into the final states mumu, mu(e), and mu(pi). Three mumu events were observed over an expected standard model background of 0.069+/-0.010 events; no events were observed in the other modes.

Journal Article↗
PubMed2001

Expression of activin A in inflammatory arthropathies.

The findings that bone marrow fibroblastoid stromal cells are important for activin A production prompted our investigation of activin A expression in fibroblast-like synoviocytes in joint capsule in this and previous studies. In the proliferative reactive synovial membrane obtained from rheumatoid arthritis patients, activin A is detected prominently in the fibroblastoid synovial cells, as well as in the smooth muscle and the endothelial layer of the arteries in these vascularized proliferative tissues. The concentration of activin A in the rheumatoid arthritis synovial fluid was 33.6+/-5.0 ng/ml, much higher than the activin A content of osteoarthritis fluid (10.0+/-1.1 ng/ml). Furthermore, our previous studies also showed that inflammatory cytokines, such as interleukin (IL)-1, transforming growth factor (TGF)-beta, interferon (IFN)-gamma, IL-8, and IL-10 markedly enhance the expression of activin A mRNA in synoviocytes. These findings are consistent with our studies in regard to the regulatory control of activin A production in bone marrow stroma and monocytes. In addition, the relationship of activin A to IL-6-induced biological activities in various cell types was also investigated. Although activin A has not been directly associated with inflammatory processes, future studies are needed to investigate its production in response to the accumulated levels of inflammatory cytokines in the synovium of the patients, as well as the quantitative differences in activin A concentrations in many patients with other inflammatory diseases.

Activins↗