Soluble c-kit receptor mobilizes hematopoietic stem cells to peripheral blood in mice

OBJECTIVE: The mechanisms of mobilization of hematopoietic stem cells (HSC) from bone marrow to peripheral blood (PB) by cytokines are poorly understood. One hypothesis is that cytokines disrupt cytoadhesive interactions of stem cells with bone marrow stroma. The soluble portion of c-kit (s-kit) binds stem cell factor (SCF) and can specifically block the ability of SCF to bind HSC. MATERIALS AND METHODS: To examine stem cell mobilization by s-kit, we prepared PB mononuclear cells from s-kit- or granulocyte colony-stimulating factor (G-CSF)-treated mice and assayed their colony-forming abilities and their long-term reconstituting abilities by transplantation into lethally irradiated Ly-5.2 congenic mice. RESULTS: We confirmed the published findings that human recombinant s-kit can block SCF-stimulated hematopoietic colony growing. We then found that s-kit could mobilize colony-forming cells from bone marrow to PB, and we found long-term reconstitution cells in the PB from s-kit-treated mice. The majority of s-kit-mobilized stem cells were in the CD34(+) cell population. We also tested the additive effect between G-CSF and s-kit. The mean percentages of donor cells in the mice transplanted with Lin(-) cells from the G-CSF-treated mice and the G-CSF/s-kit-treated mice were 44.6% and 64.8%, respectively (p=0.028). CONCLUSIONS: These findings demonstrate that stem cells with long-term engraftment capabilities can be mobilized by s-kit, and that s-kit combined with G-CSF treatment leads to significant enhancement of engraftment efficiency, suggesting mobilization via disruption between c-kit and SCF as the mechanism.     

Matrix-protein-specific regulation of Cx43 expression in cardiac myocytes subjected to mechanical load

To elucidate mechanisms responsible for mechanotransduction in the heart and define the effects of remodeling of the extracellular matrix, we cultured neonatal rat ventricular myocytes on native type I collagen, fibronectin, or denatured collagen and subjected them to uniaxial, pulsatile stretch. Changes in expression of the cardiac gap junction protein, Cx43, were measured by confocal microscopy and immunoblotting. Cells grown on fibronectin or denatured collagen exhibited significantly greater Cx43 expression than cells grown on native collagen. Stretch induced a approximately 2-fold increase in Cx43 expression in cells grown on native collagen but no increase in cells grown on fibronectin or denatured collagen. Incubation of cells on native collagen with a peptide containing the arginine-glycine-aspartate (RGD) motif upregulated Cx43 expression equivalent to that induced by stretch. Nonselective activation of integrin signaling with MnCl2 also upregulated Cx43 expression in cells grown on native collagen. This effect was blocked completely by pretreatment with anti-beta1 integrin antibody but not by anti-beta3 integrin antibody. Stretch led to a marked increase in beta1 integrin immunofluorescent signal in cells grown on native collagen but not in cells grown on fibronectin or denatured collagen. Stretch-induced upregulation of Cx43 was also blocked by anti-beta1 integrin antibody. Thus, matrix protein-myocyte interactions regulate Cx43 expression via beta1 integrin signaling initiated by mechanical stimulation in cells grown on native type I collagen, or by RGD-integrin signaling independent of mechanical stress in cells grown on fibronectin or denatured collagen. Changes in the composition of the extracellular matrix may affect electrical coupling in cardiac myocytes.     

Cibenzoline improves coronary flow velocity reserve in patients with hypertrophic obstructive cardiomyopathy

The effect of cibenzoline, a class-Ia antiarrhythmic drug, on coronary flow velocity reserve (CFVR) was examined in patients with hypertrophic cardiomyopathy using transthoracic Doppler echocardiography. Coronary flow velocity reserve was assessed in 11 patients with hypertrophic obstructive cardiomyopathy (HOCM) and 12 patients with hypertrophic nonobstructive cardiomyopathy (HNCM), before and after the intravenous administration of cibenzoline (1 mg/kg). Coronary hyperemia was induced by an intravenous infusion of adenosine triphosphate and CFVR was calculated as the ratio of hyperemic to basal mean coronary diastolic flow velocity. At baseline, CFVR was significantly correlated with left ventricular outflow tract pressure gradient (LVPG) in patients with HOCM (r = 0.67, P < 0.03). In patients with HOCM, administration of cibenzoline significantly improved impaired CFVR (2.0 ± 0.8 to 3.0 ± 1.0, P < 0.001), and reduced LVPG (55 ± 30 to 23 ± 18 mmHg, P < 0.001), while CFVR remained unchanged in patients with HNCM (2.6 ± 0.9 to 2.9 ± 0.8, P not significant). Cibenzoline not only reduces LVPG but also improves CFVR in patients with HOCM. In addition left ventricular outflow obstruction plays an important role in impaired coronary circulation in patients with HOCM.     

Serum anti-lPS antibody production in an outbreak of enterohemorrhagic Escherichia coli O157 infection among schoolchildren

Although there have been many reports of the usefulness of serodiagnosis of enterohemorrhagic Escherichia coli (EHEC) O157, the serotype of the bacteria detected and the increase in anti-LPS antibody have not always been consistent. In this study we investigated the diagnostic significance of measurements of anti-LPS antibody by ELISA in an outbreak of O157 infection among schoolchildren in whom the bacteriological test findings were clarified and the age groups were uniform. The anti-LPS antibody titer was measured in 31 patients (77 serum samples) in an outbreak of EHEC O157 : H7 infection (220 children infected) that occurred in a primary school in Morioka in 1996. The anti-O157 LPS antibody positivity rates of IgM, IgG, and IgA were 98.7%, 85.7%, and 98.7%, respectively. Between the time the meal that caused the outbreak and 19 days later, anti-O157 LPS IgM antibody and IgA antibody were detected in all patients. The specificity was investigated using control serum, and the specificity of IgM, IgG, and IgA was 93.5%, 93.5%, and 97.2%, respectively. Some samples contained antibodies against O111 and O26 LPS, but the titers were lower than the anti-O157 antibody titer. The anti-O111 antibody titer and anti-O26 antibody titer were highly correlated, suggesting that they were crossreactive antibodies for O157 LPS. No significant correlation was found between differences in clinical manifestations and the anti-O157 LPS antibody titer in this O157 outbreak in schoolchildren. It was clarified that an increase in anti-LPS antibody was found to support the diagnosis of mild cases of 0157 infection infection as well as severe cases.     

Chronic kidney disease is a risk factor for cardiovascular death in a community-based population in Japan: NIPPON DATA90.

BACKGROUND: Chronic kidney disease (CKD) has been identified as a risk factor for cardiovascular disease (CVD). METHODS AND RESULTS: The risk of cardiovascular death was evaluated in a large cohort of participants selected randomly from the overall Japanese population. Participants (mean age, 52.4 years) free of previous CVD were followed up for 10 years. Glomerular filtration rate (GFR) was estimated using the abbreviated equation developed at the Cleveland Clinic laboratory for the Modification of Diet in Renal Disease study. Of the 7,316 participants, 6.7% had CKD with a GFR<60 at baseline. Even after adjustment for other risk factors, the presence of CKD conferred an increased risk of cardiovascular death with a hazard ratio of 1.20 (95% confidence interval, 0.82-1.76). Furthermore, a negative, graded correlation between GFR and risk of cardiovascular death was observed: 1.09 (0.72-1.64) for a 60or=90). The proportion of excess cardiovascular death due to CKD was 1.3%. CONCLUSION: CKD was an independent risk factor for cardiovascular death in a community-dwelling Japanese population.     

Effect of treatment with interferon α-2b and ribavirin in patients infected with genotype 2 hepatitis C virus

Aim:  Nearly 20% of chronic hepatitis C (CHC) patients with genotype 2 hepatitis C virus (HCV) infection are not curable, even by interferon (IFN)–ribavirin combination therapy. The aim of this study is to investigate the factors that determine the efficacy of combination therapy in patients with genotype 2 HCV infection.
Methods:  Fifty patients with CHC who underwent a treatment of 6 MU IFN α-2b with ribavirin for 24 weeks were retrospectively analyzed.
Results:  All the patients showed no serum HCV-RNA within 12 weeks after starting the therapy. Forty-one of the 50 patients (82%) achieved a sustained virological response (SVR). The age, sex, genotype (2a vs. 2b) and grade/stage of the liver by histopathology and pretreatment viral load werenot different between the sustained responders and relapsers. Univariate analysis showed that an earlier viral clearance from blood and a larger number of amino acid substitutions in the interferon sensitivity determining region (ISDR) were predictors of SVR. Multivariate analysis showed that a large number of amino acid substitutions in the ISDR was a predictor of SVR.
Conclusion:  The characterization of the amino acid sequences of ISDR may be helpful for predicting a relapse after combination therapy in patients with genotype 2 HCV infection.     

The indonesian variants of CRF33_01B: Near-full length sequence analysis

Cocirculation of subtype B and CRF01_AE in Southeast Asia has led to the establishment of new recombinant forms. In our previous study, we found five samples suspected of being recombinants between subtype B and CRF01_AE, and here, we analyzed near full-length sequences of two samples and compared them to known CRFs_01B, subtype B, and CRF01_AE. Five overlapped segments were amplified with nested PCR from PBMC DNA, sequenced, and analyzed for genome mosaicism. The two Indonesian samples, 07IDJKT189 and 07IDJKT194, showed genome-mosaic patterns similar to CRF33_01B references from Malaysia, with one short segment in the 3' end of the p31 integrase-coding region, which was rather more similar to subtype B than CRF01_AE, consisting of unclassified sequences. These results suggest gene-specific continuous diversification and spread of the CRF33_01B genomes in Southeast Asia.     

Beta-cell function is a major contributor to oral glucose disposition in obese Japanese students

Determinants of glucose intolerance were studied in 163 obese Japanese young adults, 18 to 21 years old (43 females,120 males), who underwent 75-g oral glucose tolerance testing. Type 2 diabetes was newly diagnosed in 2.9% (n = 4); impaired fasting glucose (IFG) in 5.1% (n = 7); and impaired glucose tolerance (IGT) in 10.9% (n = 15). A homeostasis model assessment of insulin resistance (HOMA-IR) was used to estimate insulin sensitivity; beta-cell function during the first 30 min of the test was measured and defined as the insulinogenic index. This index was adjusted for insulin sensitivity, since this affects both beta-cell function and glucose disposition (disposition index). The relationship between insulinogenic index and 1/HOMA-IR was not hyperbolic. However, the disposition index (DI) was useful for the estimation of beta-cell function with the correct confirmation about it validity using beta-cell function index (BI). The association between insulin sensitivity and beta-cell function to glucose disposal, as measured by the area under the glucose curve (AUCg), was examined in all subjects. Insulin sensitivity was significantly related to AUCg (log HOMA-IR; R (2) = 0.142, p<0.0001). On the other hand, an inverse curvilinear relationship was observed between beta-cell function and AUCg (log(Delta I/Delta G)/HOMA-IR, R (2) = 0.411, p<0.0001). Thus, impaired beta-cell function, when estimated as DI, was strongly associated with impaired glucose disposal. In conclusion, our study showed that both insulin sensitivity and impaired beta-cell function are associated with impaired glucose metabolism, and that beta-cell function may be more important in determining glucose disposal.     

Prenatal diagnosis of trisomy 16 mosaicism manifested as pulmonary artery stenosis

Trisomy 16 mosaicism detected at midtrimester amniocentesis is rare and indicative of true fetal mosaicism. We report a case of mosaic trisomy 16 diagnosed by amniocentesis in which the sonographic findings included fetal pulmonary artery stenosis, a single umbilical artery, and early onset fetal growth restriction. The pregnancy was legally terminated. A review of previous reports suggests that abnormalities of outlet tracts are rarely encountered in fetuses with trisomy 16 mosaicism revealed via amniocentesis.     

A phase I/II study of nedaplatin and 5-fluorouracil with concurrent radiotherapy in patients with T4 esophageal cancer: Japan Clinical Oncology Group trial (JCOG 9908)

Background Nedaplatin is an analogue of cisplatin with less nonhematologic toxicity. The combination of nedaplatin and 5-fluorouracil showed a promising response rate in a previous phase II study for metastatic esophageal cancer. The purpose of this study was to determine a recommended dose and to evaluate the efficacy of nedaplatin and 5-fluorouracil combined with concurrent radiotherapy.Methods Eligibility criteria included squamous cell carcinoma of the thoracic esophagus; T4 disease without distant organ metastasis; age 20–70 years; performance status 0–2; and adequate organ functions. Patients received two cycles of nedaplatin (80 mg/m² or 90 mg/m²) on day 1 and continuous infusion of 5-fluorouracil 800 mg/m²/day on days 1–5, every 5 weeks with concurrent radiotherapy 60 Gy in 30 fractions.Results Between December 1999 and April 2002, 26 patients were accrued. The recommended dose of nedaplatin was 90 mg/m². Common grade ≥3 toxicities included leukopenia 9, neutropenia 5, thrombocytopenia 4, esophagitis 4, and esophageal fistula 3. Three of 26 patients achieved complete response (12%; 95% confidence interval, 2%–30%). With a minimum follow-up of 26 months for surviving patients, the median survival time was 12 months (95% confidence interval, 9–22 months), and the 2-year overall survival was 31% (95% confidence interval, 13%–49%).Conclusions This combined therapy is active with acceptable toxicity, however, the survival figure remains poor. Further investigation into more effective treatment is needed.