Biomedical subjects
Publications and source records attributed to S E Lee.
We report a measurement of the branching fraction for the decay B+ --> rho(+) pi(0) based on a 140 fb(-1) data sample collected with the Belle detector at the KEKB asymmetric e(+)e(-) collider. We measure the branching fraction B(B(+) --> rho(+)pi(0)) = (13.2 +/- 2.3(stat)(+1.4)(-1.9)(syst)) x 10(-6), and the CP-violating asymmetry A(CP)(B-/+ -->rho(-/+)pi(0))=0.06 +/- 0.17(stat)(+0.04)(-0.05)(syst).
Explore the source record for details and available documents.
We report a measurement of CP asymmetry parameters in the decay B0(B (0))-->J/psipi(0), which is governed by the b-->cc d transition. The analysis is based on a 140 fb(-1) data sample accumulated at the Upsilon(4S) resonance by the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. One neutral B meson in the J/psipi(0) final state is fully reconstructed for events used in this analysis. The accompanying B meson flavor is identified by its decay products. From the distribution of proper-time intervals between the two B decays, we obtain the following CP-violating parameters: S(J/psipi(0))=-0.72+/-0.42(stat)+/-0.09(syst) and A(J/psipi(0))=-0.01+/-0.29(stat)+/-0.03(syst).
We present the first evidence of the decay B0-->rho(0)pi(0), using 140 fb(-1) of data collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e(+)e(-) collider. We detect 15.1+/-4.8 signal events with a significance of 3.5 standard deviations and measure the branching fraction to be B(B0-->rho(0)pi(0))=(5.1+/-1.6(stat)+/-0.9(syst))x10(-6).
Direct CP violation in the b-->sgamma process is a sensitive probe of physics beyond the standard model. We report a measurement of the CP asymmetry in B-->X(s)gamma, where the hadronic recoil system X(s) is reconstructed using a pseudoreconstruction technique. In this approach there is negligible contamination from b-->dgamma decays, which are expected to have a much larger CP asymmetry. We find A(CP)=0.002+/-0.050(stat)+/-0.030(syst) for B-->X(s)gamma events having recoil mass smaller than 2.1 GeV/c(2). The analysis is based on a data sample of 140 fb(-1) recorded at the upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) storage ring.
OBJECTIVE: To compare patients with and with no stenting after ureteroscopy for ureteric calculi, as placing such stents is routine, although many patients complain of pain and urinary symptoms. PATIENTS AND METHODS: In all, 45 patients with ureteric calculi amenable to ureteroscopic management were prospectively randomized into a stented (23) or an unstented (22) group. Standard ureteroscopic basketing and lithotripsy was used, through a ureteroscope (8.5 F) with or without ureteric dilatation. Symptom questionnaires were completed by the patients after treatment, and they were followed radiographically to assess stone-free rate and evidence of obstruction. RESULTS: There was no statistically significant difference in age, stone size, operative duration or hospital stay between the groups (P > 0.05). Furthermore, there was no statistical difference in flank pain or urinary symptoms (P > 0.05), except haematuria, between the groups; haematuria was more severe and prolonged in the stented group (P = 0.001). CONCLUSIONS: Uncomplicated ureteroscopy for removing calculi is safe with no stent after treatment, and after considering complications and side-effects we think that the routine use of ureteric stents after uncomplicated ureteroscopy for stone extraction is unnecessary.
Eight-hundred and forty eight dogs (480 females and 368 males) not on chemoprophylaxis were examined for Dirofilaria immitis infection from 2001 to 2002. Three-hundred and thirty nine (40.0%) of 848 samples tested with antigen detecting ELISA kits showed positive reaction for D. immitis antigen. More male (43.5%) than female (37.3%) dogs were affected in this study, although there was no significant difference between both groups. Chi2 analysis showed that female and male dogs of shoreline areas had higher significant prevalence than other areas (P<0.001), respectively. The mean overall positive rates of heartworm infection were 10.4% in dogs <2-year-old group, 46.5% in 2-4-year-old group, 48.4% in 4-6-year-old group and 50.3% in >6-year-old group. The older the age, the higher the prevalence of D. immitis infection in this study. Chi2 analysis revealed a significant higher prevalence in 4-6-year-old group (100%) of shoreline areas and in 2-4-old-year group (51.2%) of urban areas (Chungnam province), respectively (P<0.001), and also revealed that the over 6-year-old group (50.3%) in mean overall prevalence had the significant higher prevalence than other age group (P<0.001). In climate comparison, our data showed that shoreline areas (69.5%) had the significant higher prevalence than urban areas and mountain areas (P<0.001). This survey confirms that the prevalence of canine heartworm infection increases, and also that the prevalence in shoreline areas is higher than in other areas in South Korea.
Phosphatidylinositol 3-kinase (PI 3-kinase) and mitogen-activated protein kinases (MAPKs) have been implicated in diverse cellular functions, including proliferation, migration, and survival. In this study, we examined the involvement of these kinases in osteoclast differentiation by employing specific inhibitors of the kinases. The osteoclast differentiation was assessed in three different culture systems: a coculture of mouse bone marrow cells with mouse calvarial osteoblasts, a mouse bone marrow cell culture in the presence of receptor activator of NF-kappaB ligand (RANKL) and macrophage-colony stimulating factor (M-CSF), and a culture of bone-resident osteoclast precursor cells driven by RANKL and M-CSF. LY294002, a specific inhibitor of PI 3-kinase, potently inhibited osteoclast differentiation in all culture systems when assessed by both tartrate-resistant acid phosphatase (TRAP) staining and dentine resorption assays. Inhibition of p38 MAPK by SB202190 resulted in a strong suppression in the exogenous RANKL dependent mouse bone marrow and bone resident precursor cell cultures. Another MAPK pathway inhibitor (PD98059), which blocks the activation of extracellular signal-regulated kinase (ERK) by inhibiting the upstream kinase MAPK-ERK kinase (MEK) 1, exerted an inhibitory effect on osteoclast differentiation only at the highest concentration tested (30 micromol/L) in many cases. Whether the signaling pathways involving these kinases are activated by RANKL was also examined. The RANKL-stimulated phosphorylation of Akt, a downstream target of PI 3-kinase, and that of ERK were observed. RANKL also stimulated the activity of p38. These results suggest that PI 3 kinase, p38, and ERK play roles in osteoclast differentiation, at least in part, by participating in RANKL signaling.
Mutations at the PKD1 locus account for 85% of cases of the common genetic disorder called autosomal dominant polycystic kidney disease (ADPKD). Screening for mutations of the PKD1 gene is complicated by the genomic structure of the 5'-duplicated region encoding 75% of the gene. To date, more than 90 mutations of the PKD1 gene have been reported in the European and American populations, and relatively little information is available concerning the pattern of mutations present in the Asian populations. We looked for mutations of the PKD1 gene in 51 unrelated Korean ADPKD patients, using polymerase chain reaction (PCR) with primer pairs located in the 3' single-copy region of the PKD1 gene and by single-strand conformation polymorphism (SSCP) analysis. We found three novel mutations, a G to A substitution at nucleotide 11012 (G3601S), a C to A substitution at nucleotide 11312 (Q3701X), and a C to T substitution at nucleotide 12971 (P4254S), and a single polymorphism involving a G to C substitution at nucleotide 11470 (L3753L). These mutations were not found in control individuals, and no other mutations in the 3' single-copy region of the PKD1 gene of patients with these mutations were observed. In particular, P4254S segregated with the disease phenotype. The clinical data of affected individuals from this study, and of previously reported Korean PKD1 mutations, showed that patients with frameshift or nonsense mutations were more prone to develop end-stage renal failure than those with missense mutations. Our findings indicate that many different PKD1 mutations are likely to be responsible for ADPKD in the Korean population, as in the Western population.
OBJECTIVE: To evaluate the expression of thrombospondin-1 (TSP-1, a potent inhibitor of angiogenesis) and vascular endothelial growth factor (VEGF, an important angiogenic factor in solid tumours) in prostate cancer, and their relationship with p53 status. PATIENTS AND METHODS: Using immunohistochemistry, the expression of VEGF, TSP-1 and p53 was assessed in 82 archival tissue specimens from 23 patients with benign prostatic hyperplasia (BPH), 22 with localized prostate cancer and 37 with metastatic prostate cancer. Seven of the last group had received androgen deprivation therapy. The relationship between the expression of VEGF, TSP-1 and p53 status was also evaluated with tumour grade and stage in patients with prostate cancer. RESULTS: The seven patients receiving hormonal treatment were excluded from the analysis because androgen deprivation significantly increased TSP-1 and decreased VEGF expression (both P < 0.01). Immunohistochemical analysis showed significantly higher VEGF and significantly lower TSP-1 expression (both P < 0.01) in prostate cancer than in BPH tissues. There was also significantly higher VEGF and significantly lower TSP-1 expression (both P < 0.05) in tissues from metastatic than localized prostate cancer. There was no significant correlation between VEGF or TSP-1 expression and Gleason score, but a significant inverse correlation between TSP-1 and VEGF expression. There was a significant association between VEGF expression and p53 status (P < 0.05), but TSP-1 expression was not associated with p53 status. CONCLUSIONS: Angiogenic factors, including VEGF and TSP-1, might be important in the development and progression of prostate cancer. These changes seem to be influenced by p53 status. Identifying the angiogenic factors involved in prostate cancer might lead to the development of diagnostic or therapeutic strategies based on anti-angiogenesis.
The extract from Smilax china root has been used as medicinal remedy and reported to retain antimicrobial and antimutagenic acitivities. In this study, a possible presence of antioxidant activity of Smilax china root extract was investigated. Methanol extract (Me) revealed the presence of high 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity (IC50 7.4 microg/ml) and protective property of cell's viability. Further fractionation with various solvent extraction and assay showed high levels of DPPH free radical scavenging activity in the ethyl acetate, butanol and water extracted fractions. In addition, V79-4 cells treated with Me of Smilax china root induced an increase of superoxide dismutase, catalase and glutathione peroxidase activities in a dose-dependent manner between 4-100 microg/ml. These results suggest that the medicinal component of the root of Smilax china extracts also contains antioxidant activity.
Broken DNA ends are rejoined by non-homologous end-joining (NHEJ) pathways requiring the Ku proteins (Ku70, Ku80), DNA ligase IV and its associated protein Lif1/Xrcc4 (ref. 1). In mammalian meiotic cells, Ku protein levels are much lower than in somatic cells, apparently reducing the capacity of meiotic cells to carry out NHEJ and thereby promoting homologous recombination. In Saccharomyces cerevisiae, NHEJ is also downregulated in meiosis-competent MATa/MAT alpha diploid cells in comparison with diploids or haploids expressing only MATa or MAT alpha. Diploids expressing both MATa and MAT alpha show enhanced mitotic homologous recombination. Here we report that mating-type-dependent regulation of NHEJ in budding yeast is caused in part by transcriptional repression of both LIF1 and the gene NEJ1 (YLR265C)--identified from microarray screening of messenger RNAs. Deleting NEJ1 reduces NHEJ 100-fold in MATa or MAT alpha haploids. Constitutive expression of NEJ1, but not expression of LIF1, restores NHEJ in MATa/MAT alpha cells. Nej1 regulates the subcellular distribution of Lif1. A green fluorescent protein (GFP)-Lif1 fusion protein accumulates in the nucleus in cells expressing NEJ1 but is largely cytoplasmic when NEJ1 is repressed.
We identified recently an endogenous murine leukemia virus (MuLV) envelope protein as a new autoantigen reactive with autoimmune diabetic mouse sera and observed immunosuppressive activity of this envelope protein. In the present study, to elucidate the mechanism involved, we treated macrophages with the envelope protein and investigated activation of macrophage. We found enhancements of iNOS mRNA and nitrite in envelope protein-treated RAW264.7 cells and peritoneal macrophages. The stimulation was highly envelope protein-specific, and also time- and dose-dependent. The activation pattern was similar to that elicited by lipopolysaccharide (LPS) since the envelope protein showed a synergistic effect on macrophage activation in conjunction with interferon gamma (IFN-gamma). Furthermore, deacylated LPS as a competitive inhibitor of LPS showed inhibition of envelope protein-mediated macrophage activation. These data show that MuLV envelope protein can be a new macrophage activator and suggest that the retroviral envelope protein may elicit immunosuppressive activity through macrophage activation.
Differentiated osteoclasts have a short life span. We tested various cytokines and growth factors for the effects on the survival of purified mature osteoclasts. In the absence of any added factors, osteoclasts exhibited the survival rate of less than 25% after a 24-h incubation. Among the tested factors, tumor necrosis factor-alpha (TNF-alpha) was found to increase the survival rate to approximately 80%. The TNF-alpha-enhanced survival of osteoclasts appeared to be associated with reduction in apoptosis and suppression of caspase activation. The antiapoptotic signaling pathways involved in the TNF-alpha-induced osteoclast survival were investigated. TNF-alpha treatment increased the phosphorylation of Akt in osteoclasts, which was suppressed by a phosphatidylinositol 3-kinase inhibitor LY294002 and an Src family kinase-selective inhibitor PP1. These inhibitors also attenuated the TNF-alpha stimulation of osteoclast survival. In addition an increase in the phosphorylation of ERK was observed upon TNF-alpha stimulation. PD98059, a specific inhibitor of the ERK-activating kinase MEK-1, abolished the TNF-alpha-induced ERK phosphorylation and osteoclast survival, and in these responses the involvement of Grb2 and ceramide was observed. These results suggest that TNF-alpha promotes the survival of osteoclasts by engaging the phosphatidylinositol 3-kinase Akt and MEK/ERK signaling pathways.
Saccharomyces cells with a single unrepaired double-strand break (DSB) will adapt to checkpoint-mediated G2/M arrest and resume cell cycle progression. The decision to adapt is finely regulated by the extent of single-stranded DNA generated from a DSB. We show that cells lacking the recombination protein Tid1p are unable to adapt, but that this defect is distinct from any role in recombination. As with the adaptation-defective mutations yku70Delta and cdc5-ad, permanent arrest in tid1Delta is bypassed by the deletion of the checkpoint gene RAD9. Permanent arrest of tid1Delta cells is suppressed by the rfa1-t11 mutation in the ssDNA binding complex RPA, similar to yku70Delta, whereas the defect in cdc5-ad is not suppressed. Unlike yku70Delta, tid1Delta does not affect 5'-to-3' degradation of DSB ends. The tid1Delta defect cannot be complemented by overexpressing the homolog Rad54p, nor is it affected in rad51Delta tid1Delta, rad54Delta tid1Delta, or rad52Delta tid1Delta double mutants that prevent essentially all homologous recombination. We suggest that Tid1p participates in monitoring the extent of single-stranded DNA produced by resection of DNA ends in a fashion that is distinct from its role in recombination.
The Dbf2 protein kinase functions as part of the mitotic-exit network (MEN), which controls the inactivation of the Cdc28-Clb2 kinase in late mitosis [1]. The MEN includes the Tem1 GTP binding protein; the kinases Cdc15 and Cdc5; Mob1, a protein of unknown function; and the phosphatase Cdc14 [2]. Here we have used Dbf2 kinase activity to investigate the regulation and order of function of the MEN. We find that Tem1 acts at the top of the pathway, upstream of Cdc15, which in turn functions upstream of Mob1 and Dbf2. The Cdc5 Polo-like kinase impinges at least twice on the MEN since it negatively regulates the network, probably upstream of Tem1, and is also required again for Dbf2 kinase activation. Furthermore, we find that regulation of Dbf2 kinase activity and actin ring formation at the bud neck are causally linked. In metaphase-arrested cells, the MEN inhibitor Bub2 restrains both Dbf2 kinase activity [3] and actin ring formation [4]. We find that the MEN proteins that are required for Dbf2 kinase activity are also required for actin ring formation. Thus, the MEN is crucial for the regulation of cytokinesis, as well as mitotic exit.
The incorporation of potentially catalytic groups into DNA is of interest for the in vitro selection of novel deoxyribozymes. We have devised synthetic routes to a series of three C7 modified 7-deaza-dATP derivatives with pendant aminopropyl, Z-aminopropenyl and aminopropynyl side chains. These modified triphosphates have been tested as substrates for Taq polymerase during PCR. All the modifications are tolerated by this enzyme, with the aminopropynyl side chain giving the best result. Most protein enzymes have more than one type of catalytic group located in their active site. By using C5-imidazolyl-modified dUTPs together with 3-(aminopropynyl)-7-deaza-dATP in place of the natural nucleotides dTTP and dATP, we have demonstrated the simultaneous incorporation of both amino and imidazolyl moieties into a DNA molecule during PCR. The PCR product containing the four natural bases was fully digested by XbaI, while PCR products containing the modified 7-deaza-dATP analogues were not cleaved. Direct evidence for the simultaneous incorporation during PCR of an imidazole-modified dUTP and an amino-modified 7-deaza-dATP has been obtained using mass spectrometry.
The incorporation of potentially catalytic groups in DNA is of interest for the in vitro selection of novel deoxyribozymes. A series of 10 C5-modified analogues of 2'-deoxyuridine triphosphate have been synthesised that possess side chains of differing flexibility and bearing a primary amino or imidazole functionality. For each series of nucleotide analogues differing degrees of flexibility of the C5 side chain was achieved through the use of alkynyl, alkenyl and alkyl moieties. The imidazole function was conjugated to these C5-amino-modified nucleotides using either imidazole 4-acetic acid or imidazole 4-acrylic acid (urocanic acid). The substrate properties of the nucleotides (fully replacing dTTP) with TAQ polymerase during PCR have been investigated in order to evaluate their potential applications for in vitro selection experiments. 5-(3-Aminopropynyl)dUTP and 5-(E-3-aminopropenyl)dUTP and their imidazole 4-acetic acid- and urocanic acid-modified conjugates were found to be substrates. In contrast, C5-amino-modified dUTPs with alkane or Z-alkene linkers and their corresponding conjugates were not substrates. The incorporation of these analogues during PCR has been confirmed by inhibition of restriction enzyme digestion using XBAI and by mass spectrometry of the PCR products.