Biomedical subjects

C W Park

Publications and source records attributed to C W Park.

At least 19 recordsLinked to original sources

PubMed2006

Observation of B+ --> Lambda c+ Lambda c- K+ and B0 --> Lambda c+ Lambda c- K0 decays.

We report the first measurements of the doubly charmed baryonic B decays B --> Lambda c+ Lambda c- K. The B+ --> Lambda c+ Lambda c- K+ decay is observed with a branching fraction of (6.5(-0.9)(+1.0)+/-1.1+/-3.4)x10(-4) and a statistical significance of 15.4sigma. The B0 --> Lambda c+ Lambda c- K0 decay is observed with a branching fraction of (7.9(-2.3)(+2.9)+/-1.2+/-4.1)x10(-4) and a statistical significance of 6.6sigma. The branching fraction errors are statistical, systematic, and the error resulting from the uncertainty of the Lambda c+ --> pK- pi+ decay branching fraction. The analysis is based on 357 fb(-1) of data accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e- collider.

Journal Article↗

PubMed2006

Measurement of the quark mixing parameter cos2phi1 using time-dependent Dalitz analysis of B0 -->D[KS(0)pi + pi-]h0.

We present a measurement of the angle phi1 of the Cabibbo-Kobayashi-Maskawa unitarity triangle using a time-dependent Dalitz analysis of D-->KS(0)pi + pi- decays produced in neutral B meson decay to a neutral D meson and a light meson (B0-->D*h0). The method allows a direct extraction of 2phi1 and, therefore, helps to resolve the ambiguity between 2phi1 and pi-2phi1 in the measurement of sin2phi1. We obtain sin2phi1= 0.78 +/- 0.44 +/- 0.22 and cos2varphi1 = 1.87(-0.53-0.32)(+0.40 + 0.22). The sign of cos2phi1 is determined to be positive at 98.3% C.L.

Journal Article↗

PubMed2006

Measurement of D0-->pilnu(Klnu) form factors and absolute branching fractions.

Using a 282 fb-1 data sample collected by the Belle experiment at the KEKB e+e- collider, we study D0 decays to K-l+nu and pi-l+nu final states. The D0 flavor and momentum are tagged through a full reconstruction of the recoiling charm meson and additional mesons from fragmentation. The reconstruction method provides very good resolution in neutrino momentum and in q2=(pl+pnu)2. Normalizing to the total number of D0 tags, we measure the absolute branching fractions to be B(D0-->Klnu)=(3.45+/-0.07stat+/-0.20syst)% and B(D0-->pilnu)=(0.255+/-0.019stat+/-0.016syst)% and the semileptonic form factors (within the modified pole model) f+K(0)=0.695+/-0.007stat+/-0.022syst and f+pi(0)=0.624+/-0.020stat+/-0.030syst.

Journal Article↗

PubMed2006

Measurement of azimuthal asymmetries in inclusive production of hadron pairs in e(+)e(-) annihilation at Belle.

The Collins effect connects transverse quark spin with a measurable azimuthal dependence in the yield of hadronic fragments around the quark's momentum vector. Using two different reconstruction methods, we find evidence of statistically significant azimuthal asymmetries for charged pion pairs in e(+)e(-) annihilation at a center-of-mass energy of 10.52 GeV, which can be attributed to a transverse polarization of the primordial quarks. The measurement was performed using a sample of 79 x 10(6) hadronic events collected with the Belle detector.

Journal Article↗

PubMed2006

Observation of a chi(c2)' candidate in gamma gamma --> DD production at belle.

We report on a search for new resonant states in the process gamma gamma --> DD. A candidate C-even charmonium state is observed in the vicinity of 3.93 GeV/c2. The production rate and the angular distribution in the gamma gamma center-of-mass frame suggest that this state is the previously unobserved chi(c2)', the 2(3)P2 charmonium state.

Journal Article↗

PubMed2006

PPARalpha agonist fenofibrate improves diabetic nephropathy in db/db mice.

Peroxisome proliferator-activated receptor alpha (PPARalpha) is a member of the ligand-activated nuclear receptor superfamily, and plays an important role in lipid metabolism and glucose homeostasis. The purpose of this study is to determine whether the activation of PPARalpha by fenofbrate would improve diabetes and its renal complications in type II diabetes mellitus. Male C57 BLKS db/db mice and db/m controls at 8 weeks of age were divided to receive either a regular diet chow (db/db, n=8; db/m, n=6) or a diet containing fenofibrate (db/db, n=8; db/m, n=7). Mice were followed for 8 weeks. Fenofibrate treatment dramatically reduced fasting blood glucose (P<0.001) and HbA1c levels (P<0.001), and was associated with decreased food intake (P<0.01) and slightly reduced body weight. Fenofibrate also ameliorated insulin resistance (P<0.001) and reduced plasma insulin levels (P<0.05) in db/db mice. Hypertrophy of pancreatic islets was decreased and insulin content markedly increased (P<0.05) in fenofibrate-treated diabetic animals. In addition, fenofibrate treatment significantly reduced urinary albumin excretion (P<0.001). This was accompanied by dramatically reduced glomerular hypertrophy and mesangial matrix expansion. Furthermore, the addition of fenofibrate to cultured mesangial cells, which possess functional active PPARalpha, decreased type I collagen production. Taken together, the PPARalpha agonist fenofibrate dramatically improves hyperglycemia, insulin resistance, albuminuria, and glomerular lesions in db/db mice. The activation of PPARalpha by fenofibrate in mesangial cells may partially contribute to its renal protection. Thus, fenofibrate may serve as a therapeutic agent for type II diabetes and diabetic nephropathy.

Albuminuria↗

PubMed2006

Comparison between transuncal approach and upper vertebral transcorporeal approach for unilateral cervical radiculopathy - a preliminary report.

OBJECTIVE: The surgical treatments for unilateral cervical radiculopathy have been performed by either the anterior or posterior approach. The anterior approach has usually been used more than the posterior approach. The authors compared the results of newly advanced upper vertebral transcorporeal (UVTC) approach with those of the original transuncal (TU) approach in the anterior approach. METHODS: The anterior cervical microforaminotomy was performed for 60 patients (male:female=40:20) from June, 2000 to October, 2003. 40 patients were treated by the TU approach while 20 patients were operated on by the new UVTC approach. The authors analyzed postoperative changes of disc height, the spinal instability, the average length of hospital stay, the degree of patients' satisfaction and complications from each approach. The mean follow-up period was 9.5 months. RESULTS: In the TU approach, postoperative intervertebral disc height was decreased from 7.1+/-0.65 mm to 6.2+/-0.61 mm. In the UVTC approach, postoperative intervertebral disc height was decreased from 6.6+/-0.43 mm to 6.3+/-0.41 mm. The average length of hospital stay was 5.2 days for the TU approach and 3.4 days for the UVTC approach. In the TU approach, 28 patients experienced excellent results, 11 patients experienced good results, one patient who experienced a fair result was operated by anterior cervical fusion because of a recurrent herniated disc. In the UVTC approach, 16 patients had excellent results and four patients experienced good results. CONCLUSIONS: This comparative study demonstrates that the UVTC approach is a better surgical technique than the TU approach considering the preservation of disc height, spinal stability, length of hospital stay, degree of satisfaction and complications.

Activities of Daily Living↗

PubMed2006

Tissue-specific regulation of malonyl-CoA decarboxylase activity in OLETF rats.

AIM: The intracellular concentration of malonyl-CoA, a key regulator of fatty acid oxidation, is determined both from its synthesis by acetyl-CoA carboxylase and from its degradation by malonyl-CoA decarboxylase (MCD). The aim of our study was to investigate the activity and mRNA expression of MCD under insulin resistance and after treatment with insulin sensitizers in different tissues. METHODS: We treated 18-week Otusuka Long-Evans Tokushima Fatty (OLETF) rats with pioglitazone (10 mg/kg/day) or metformin (300 mg/kg/day) for 8 weeks and determined the activity and mRNA expression of MCD in diabetic OLETF and non-diabetic Long-Evans Tokushima Otsuka (LETO) rats in myocardial and skeletal muscles, and in liver. RESULTS: The MCD activities of myocardial and skeletal muscles were remarkably reduced in OLETF rats compared with LETO rats (995 +/- 114 vs. 2012 +/- 359, 58 +/- 11 vs. 167 +/- 40 pmol/min/mg protein; p = 0.005 and p = 0.010). Surprisingly, after pioglitazone treatment, not after metformin, the MCD activities of myocardial and skeletal muscles (1906 +/- 320 and 259 +/- 44 pmol/min/mg protein) increased up to the levels in LETO rats. MCD mRNA expression in OLETF rats was also reduced in myocardial and skeletal muscles vs. LETO rats (p = 0.049 and p = 0.008) and was unchanged by pioglitazone or metformin treatment. In the liver, MCD activity and mRNA expression were similar in OLETF and LETO rats. CONCLUSION: Pioglitazone treatment restored MCD activity to non-diabetic level and improved the restrained fatty acid metabolism in myocardial and skeletal muscles caused by insulin-resistant diabetic status.

Animals↗

PubMed2005

Observation of a near-threshold omegaJ/psi mass enhancement in exclusive B-->KomegaJ/psi decays.

We report the observation of a near-threshold enhancement in the omegaJ/psi invariant mass distribution for exclusive B-->KomegaJ/psi decays. The results are obtained from a 253 fb(-1) data sample that contains 275 x 10(6) BB pairs that were collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric energy e(+)e(-) collider. The statistical significance of the omegaJ/psi mass enhancement is estimated to be greater than 8sigma.

Journal Article↗

PubMed2005

Observation of B+-->K1(1270)+gamma.

We report the observation of the radiative decay B+-->K1(1270)(+) gamma using a data sample of 140 fb(-1) taken at the Upsilon(4S) resonance with the Belle detector at the KEKB e+e- collider. We find the branching fraction to be B(B+-->K1(1270)(+)gamma)=(4.3+/-0.9(stat.)+/-0.9(syst.))x10(-5) with a significance of 7.3sigma. We find no significant signal for B+-->K1(1400)(+)gamma and set an upper limit B(B+-->K1(1400)(+)gamma)<1.5 x 10(-5) at the 90% confidence level. We also measure inclusive branching fractions for B+-->K+pi+pi-gamma and B0-->K0pi+pi-gamma in the mass range 1 GeV/c(2)<M(K+(0)pi+pi-)<2 GeV/c(2).

Journal Article↗

PubMed2005

The distribution of inhibitory and excitatory synapses on single, reconstructed jaw-opening motoneurons in the cat.

In a previous study, we reported that the distribution of inhibitory input, in contrast to excitatory input, decreased somatofugally along dendrites of cat jaw-closing alpha-motoneurons [J Comp Neurol 414 (1999) 454]. The present study examined the distribution of GABA, glycine, and glutamate immunopositive boutons covering horseradish peroxidase-labeled cat jaw-opening motoneurons. The motoneurons were divided into four compartments: the soma, and primary, intermediate, and distal dendrites. Ninety-seven percent of the total number of studied boutons had immunoreactivity for at least one of the three amino acids. The proportion of boutons immunoreactive for GABA and/or glycine was lower than the proportion of boutons immunoreactive for glutamate. Boutons immunoreactive to glycine alone were more numerous than boutons double-labeled for GABA and glycine, which, in turn, occurred more frequently than boutons immunoreactive to GABA alone. The percentage synaptic covering (proportion of membrane covered by synaptic boutons) of the putatively excitatory (glutamate containing) and putatively inhibitory (GABA and/or glycine containing) boutons decreased somatofugally along the dendrites. Such systematic variations were not seen in the packing density (number of boutons per 100 microm(2)); the packing density showed a distinct drop between the soma and primary dendrites but did not differ significantly among the three dendritic compartments. Overall, the packing density was slightly higher for the putatively excitatory boutons than for the inhibitory ones. When taken together with previous analyses of jaw-closing alpha-motoneurons the present data on jaw-opening alpha-motoneurons indicate that the two types of neuron differ in regard to the nature of synaptic integration in the dendritic tree.

Amino Acid Transport System X-AG↗

PubMed2005

Tacrolimus decreases the expression of eotaxin, CCR3, RANTES and interleukin-5 in atopic dermatitis.

BACKGROUND: There is a lack of studies on the effect of tacrolimus on eosinophils and related molecules including eotaxin, CCR3, RANTES and interleukin (IL)-5. OBJECTIVES: To investigate the effects of tacrolimus on in vivo eosinophil counts and on the related molecules eotaxin, CCR3, RANTES and IL-5 in patients with atopic dermatitis (AD). METHODS: Lesional skin specimens and sera were obtained from 15 patients with AD and from 15 normal controls. For 8 weeks, the patients with AD applied 0.03% tacrolimus ointment to all affected areas twice daily. Blood sampling and skin biopsies were then repeated. We evaluated serum eotaxin and IL-5 levels, and tissue eotaxin, CCR3, RANTES and IL-5 levels. Additionally, tissue levels of eotaxin and CCR3 mRNA were measured. RESULTS: After treatment with topical tacrolimus twice daily for 8 weeks, significant decreases were found in serum IL-5 levels, immunoreactive cell counts of eotaxin, IL-5, CCR3 and RANTES in AD skin, and tissue eosinophil counts. However, the change in the serum eosinophil count was not statistically significant, and mRNA levels of eotaxin and CCR3 were not decreased significantly after treatment. CONCLUSIONS: Topical tacrolimus reduces the number of eosinophils in tissue and suppresses the expression of eotaxin, CCR3, RANTES and IL-5 related to proliferation, recruitment, activation and survival of eosinophils.

Adolescent↗

PubMed2005

Tacrolimus reduces staphylococcal colonization on the skin in Korean atopic dermatitis patients.

It is well known that topical tacrolimus is safe and effective in the treatment of atopic dermatitis (AD) patients. Tacrolimus is primarily an immunosuppressive agent without any antistaphylococcal effects. Thus colonization of Staphylococcus aureus on the skin of patients treated with this agent might be increased. The purpose of this study was to determine the effect of tacrolimus on S. aureus colonization in patients with AD and to compare the results with clinical severity and skin barrier function. We enrolled 65 patients with moderate to severe AD. They were treated with 0.03% tacrolimus ointment twice daily for 4 weeks. Clinical severity was assessed by the eczema area and severity index (EASI). S. aureus colonization was measured by the tape method. Skin barrier function was checked by measuring transepidermal water loss (TEWL). Evaluations were performed at weeks 0 (baseline), 1, 2 and 4. The results were compared and statistical analysis was performed. S. aureus colonization was significantly decreased with tacrolimus treatment at week 1 compared with baseline. However, there were no differences among weeks 1, 2 and 4. EASI and TEWL showed a decreasing tendency in a time-dependent fashion. The correlations between data were variable.

Administration, Topical↗

PubMed2005

Role of cytokines in preterm labor and birth.

Preterm birth (defined as delivery prior to 37 weeks' gestation) complicates 5-10% of all births. It is a major cause of perinatal mortality and morbidity. Approximately 20% of all preterm births are iatrogenic resulting from obstetric intervention for maternal and/or fetal indications. Of the remainder, 2/3 are spontaneous preterm labor with or without preterm premature rupture of the membranes (pPROM). Preterm labor is a syndrome rather than a diagnosis since the etiologies are varied. Risk factors include, among others, pPROM, cervical insufficiency, pathologic uterine distention (polyhydramnios, multiple gestation), uterine anomalies, intrauterine infection/inflammation, and social factors (stress, smoking, heavy work). The final common pathway appears to be activation of the inflammatory cascade. Bacterial colonization and/or inflammation of the choriodecidual interface induces production of pro-inflammatory cytokines that, in turn, lead to neutrophil activation and the synthesis and release of uterotonins such as prostaglandins (which cause uterine contractions) and metalloproteinases (that weaken fetal membranes and remodel cervical collagen). This monograph reviews the role of cytokines in the pathophysiology of preterm labor and delivery.

Adolescent↗

PubMed2004

Evidence for B+-->omegal+nu.

We have searched for the decay B+-->omegal(+)nu (l=e or mu) in 78 fb(-1) of Upsilon(4S) data (85x10(6)BB events) accumulated with the Belle detector. The final state is fully reconstructed using the omega decay into pi(+)pi(-)pi(0), combined with detector hermeticity to estimate the neutrino momentum. A signal of 414+/-125 events is found in the data, corresponding to a branching fraction of (1.3+/-0.4+/-0.2+/-0.3)x10(-4), where the first two errors are statistical and systematic, respectively. The third error reflects the estimated form-factor uncertainty.

Journal Article↗

PubMed2004

Search for the lepton-flavor-violating decay tau- -->micro-eta at Belle.

We have searched for the lepton flavor violating decay tau(-)-->micro(-)eta using a data sample of 84.3 fb(-1) accumulated with the Belle detector at KEK. The eta meson was detected through the decay modes: eta-->gammagamma and pi(+)pi(-)pi(0). No signal candidates are found, and we obtain an upper limit for the branching fraction B(tau(-)-->micro(-)eta)<3.4 x 10(-7) at the 90% confidence level.

Journal Article↗

PubMed2004

Observation of B(+)-->pppi+, B0-->ppK0, and B(+)-->ppK(*+).

We report the first observation of a b-->u type charmless baryonic B decay, B+-->pppi(+), as well as b-->s type B0-->ppK0 and B+-->ppK(*+) decays. The analysis is based on a 78 fb(-1) data sample recorded on the Upsilon(4S) resonance with the Belle detector at KEKB. We find B(B+-->pppi(+))=(3.06(+0.73)(-0.62)+/-0.37)x10(-6), B(B0-->ppK0)=(1.88(+0.77)(-0.60)+/-0.23)x10(-6), and B(B+-->ppK(*+))=(10.3(+3.6+1.3)(-2.8-1.7))x10(-6). We also update B(B+-->ppK+)=(5.66(+0.67)(-0.57)+/-0.62)x10(-6) and present an upper limit on B(B0-->ppK(*0)) at the 90% confidence level. A common feature of the observed decay modes is threshold peaking in baryon pair invariant mass.

Journal Article↗

PubMed2004

Observation of the radiative decay D0-->phigamma.

We report the observation of the decay D0-->phigamma with a statistical significance of 5.4sigma in 78.1 fb(-1) of data collected by the Belle experiment at the KEKB e+e- collider. This is the first observation of a flavor-changing radiative decay of a charmed meson. The Cabibbo- and color-suppressed decays D0-->phipi(0), phieta are also observed for the first time. We measure branching fractions B(D0-->phigamma)=[2.60(+0.70)(-0.61)(stat)+0.15-0.17(syst)] x 10(-5), B(D0-->phipi(0))=[8.01+/-0.26(stat)+/-0.47(syst)] x 10(-4), and B(D0-->phieta)=[1.48+/-0.47(stat)+/-0.09(syst)] x 10(-4).

Journal Article↗