TGFß1 synergizes with FLT3 ligand to induce chemoresistant quiescence in acute lymphoblastic leukemia with MLL gene rearrangements.

Fms-like tyrosine kinase 3 (FLT3) is highly expressed in mixed-lineage leukemia (MLL) gene-rearranged acute lymphoblastic leukemia (MLL+ALL) with a dismal prognosis. We previously reported that FLT3 ligand (FL) stimulation induced cell cycle arrest in MLL+ALL cells leading to resistance against anti-leukemic agents. Given that FL stimulation enhanced transforming growth factor (TGF)ß1 mRNA levels in MLL+ALL cells, we extensively examined the effect of TGFß1 on the cell cycle progression and chemosensitivity in MLL+ALL cells, and found that TGFß1 stimulation induced MLL+ALL cells into cell cycle arrest resistant to arabinosyl cytosine; its effect was markedly enhanced in synergy with FL. Thus, it is likely that TGFß1 and FL, both abundantly produced by bone marrow stromal cells, function in a coordinated manner to render MLL+ALL cells chemoresistant, which should lead to the development of minimal residual disease (MRD) resulting in relapse. The use of inhibitors against FLT3 and TGFß1 may become a useful strategy for eradicating MRD in MLL+ALL.

Early use of allogeneic hematopoietic stem cell transplantation for infants with MLL gene-rearrangement-positive acute lymphoblastic leukemia.

Sixty-two infants with MLL gene-rearrangement-positive acute lymphoblastic leukemia (MLL-r ALL) were treated with the MLL03 protocol of the Japanese Pediatric Leukemia/Lymphoma Study Group: short-course intensive chemotherapy followed by early allogeneic hematopoietic stem cell transplantation (HSCT) within 4 months of the initial induction. The 4-year event-free survival and overall survival rates were 43.2% (95% confidence interval (CI)=30.7-55.1%) and 67.2% (53.8-77.4%), respectively. A univariate analysis showed younger age (<90 days at diagnosis), central nervous system disease and poor response to initial prednisolone therapy significantly associated with poor prognosis (P<0.05). In a multivariate analysis, younger age at diagnosis tended to be associated with poor outcome (hazard ratio=1.969; 95% CI=0.903-4.291; P=0.088). Although the strategy of early use of HSCT effectively prevented early relapse and was feasible for infants with MLL-r ALL, the fact that substantial number of patients still relapsed even though transplanted in their first remission indicates the limited efficacy of allogeneic HSCT for infants with MLL-r ALL. Considering the risk of severe late effects, indications for HSCT should be restricted to specific subgroups with poor risk factors. An alternative approach incorporating molecular-targeted drugs should be established.

Comparison of multiple parameters obtained on 3T pulsed arterial spin-labeling, diffusion tensor imaging, and MRS and the Ki-67 labeling index in evaluating glioma grading.

BACKGROUND AND PURPOSE: Pulsed arterial spin-labeling, DTI, and MR spectroscopy provide useful data for tumor evaluation. We evaluated multiple parameters by using these pulse sequences and the Ki-67 labeling index in newly diagnosed supratentorial gliomas. MATERIALS AND METHODS: All 32 patients, with grade II (3 each of diffuse astrocytoma, oligodendroglioma, and oligoastrocytoma), grade III (3 anaplastic astrocytomas, 4 anaplastic oligodendrogliomas, and 1 anaplastic oligoastrocytoma), and grade IV (14 glioblastomas and 1 glioblastoma with an oligodendroglioma component) cases underwent pulsed arterial spin-labeling, DTI, and MR spectroscopy studies by using 3T MR imaging. The following variables were used to compare the tumors: relative cerebral blood flow, fractional anisotropy; ADC tumor/normal ratios; and the Cho/Cr, NAA/Cho, NAA/Cr, and lactate/Cr ratios. A logistic regression and receiver operating characteristic analysis were used to assess parameters with a high sensitivity and specificity to identify the threshold values for separate grading. We compared the Ki-67 index with various MR imaging parameters in tumor specimens. RESULTS: Significant correlations were observed between the Ki-67 index and the mean, maximum, and minimum ADC, Cho/Cr, and lactate/Cr ratios. The receiver operating characteristic analysis showed that the combination of the minimum ADC and Cho/Cr ratios could differentiate low-grade and high-grade gliomas, with a sensitivity and specificity of 87.0% and 88.9%, respectively. The mean and maximum relative cerebral blood flow ratios were used to classify glioblastomas from other-grade astrocytomas, with a sensitivity and specificity of 92.9% and 83.3%, respectively. CONCLUSIONS: Our findings indicate that pulsed arterial spin-labeling, DTI, and MR spectroscopy are useful for predicting glioma grade. Additionally, the parameters obtained on DTI and MR spectroscopy closely correlated with the proliferative potential of gliomas.

Influence of Th2 cells on hair cycle/growth after repeated cutaneous application of hapten.

Exposure to contact allergens in order to produce allergic contact dermatitis (ACD) seems to induce hair cycle/growth, but the mechanism of this remains unclear. In the current study, we investigated this mechanism and found that repeated application of hapten induced production of interleukin (IL)-4 in lymph-node immune cells. In addition, hair growth was induced in mice after the adoptive transfer of T-helper (Th)2 cells that had been purified from mice exposed to repeated cutaneous application of hapten. These findings lead us to speculate that Th2 cells that are repeatedly hapten-sensitized are recruited to hapten-challenged skin areas, and thus stimulate the production of IL-4 in the vicinity of the hair follicles, which influences hair cycle/growth. Our results may provide fundamental insights into the mechanism of contact hypersensitivity-induced hair cycle/growth.

Associations between capsular serotype, multilocus sequence type, and macrolide resistance in Streptococcus agalactiae isolates from Japanese infants with invasive infections.

SUMMARY Streptococcus agalactiae (group B streptococcus; GBS) isolates (n = 150) from infants with invasive infections between 2006 and 2011 were analysed for capsular serotype, multilocus sequence type, and antibiotic susceptibility. In cases with late-onset disease (n = 115), primary meningitis was predominant (62.6%), but represented only 39.1% in cases with early-onset disease (n = 23). The most common serotype was III (58.7%), followed by Ia (21.3%) and Ib (12.7%). Sequence types (STs) of serotype III strains included ST17 (50.0%), ST19 (26.1%), ST335 (18.2%), ST27 (4.5%), and ST1 (1.1%). Predominant STs of serotypes Ia and Ib were ST23 (81.3%) and ST10 (84.2%), respectively. No penicillin-resistant strains were detected, but 22·0% of strains had mef(A/E), erm(A), or erm(B) genes, which mediate macrolide resistance. A new ST335, possessing an mef(A/E) gene belonging to clonal complex 19 gradually increased in frequency. Improved prevention of invasive GBS infections in infants requires timely identification, and ultimately vaccine development.

Development of a loop-mediated isothermal amplification assay for rapid and simple detection of Erysipelothrix rhusiopathiae.

UNLABELLED: Erysipelothrix rhusiopathiae is a causative agent of swine erysipelas. We developed a novel and highly specific loop-mediated isothermal amplification (LAMP) assay for sensitive and rapid detection of E. rhusiopathiae. The LAMP assay correctly detected 39 E. rhusiopathiae strains. No LAMP products were detected from 14 non-rhusiopathiae Erysipelothrix and 16 non-Erysipelothrix strains, including E. tonsillarum serovar 10 strains, which are difficult to be discriminated from E. rhusiopathiae strains. These results were consistent with those obtained by a conventional E. rhusiopathiae-specific PCR assay. Starting with DNA extraction from a single colony, the gel-based PCR assay took 4 h to provide a result, but the LAMP assay was faster, requiring only 37-80 min. The conventional culture test required more than 3-4 days to isolate and identify E. rhusiopathiae in the enrichment cultures. In contrast, the LAMP assay required less than 22 h from the beginning of the enrichment culture to final determination. These results suggest that the LAMP assay is useful as an adjunct to facilitate early diagnosis of swine erysipelas. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of a loop-mediated isothermal amplification (LAMP) assay for simple and cost-effective detection of E. rhusiopathiae from swine samples. The LAMP assay provided more rapid detection of the bacterium than conventional PCR and biochemical-based assays, and it may potentially facilitate surveillance and early diagnosis of swine erysipelas in the field.

Suppression of the let-7b microRNA pathway by DNA hypermethylation in infant acute lymphoblastic leukemia with MLL gene rearrangements.

MicroRNAs (miRNAs) regulate cell proliferation and differentiation by controlling the expression of proteins involved in many signaling pathways. Recent studies have shown that dysregulation of miRNA expression is associated with increased tumorigenicity and a poor prognosis in several types of cancers. The miRNA let-7b is one of the severely downregulated miRNAs in mixed-lineage leukemia (MLL)-rearranged acute lymphoblastic leukemia (ALL) patients. In vitro transfection of leukemogenic MLL fusion genes into human embryonic kidney-293 cells suppressed let-7b expression. In leukemic cells with an MLL fusion gene, the regulatory region for let-7b expression was hypermethylated, and its expression was partially recovered after culturing the cells with the demethylating agent 5-azacitidine. These results suggest that loss of let-7b expression may be one of the consequences of oncogenic MLL fusion proteins, and contributes to leukemogenesis possibly through the upregulation of let-7b-regulated target genes with leukemogenic potential in hematopoietic cells. The enforced expression of let-7b in ALL cell lines with an MLL fusion gene inhibited their growth, indicating the possible use of let-7b as a new therapeutic tool for refractory infant ALL with an MLL fusion gene.

BCR-ABL regulates death receptor expression for TNF-related apoptosis-inducing ligand (TRAIL) in Philadelphia chromosome-positive leukemia.

Allogeneic stem cell transplantation (allo-SCT) is a potentially curative therapy for chronic myeloid leukemia and Philadelphia chromosome-positive (Ph(+)) acute lymphoblastic leukemia, and the graft-vs-leukemia (GVL) effect can eradicate residual leukemia after allo-SCT. Ph(+) leukemia cells frequently express death-inducing receptors (DR4 and DR5) for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), which is one of the cytotoxic ligands expressed on cytotoxic T cells and natural killer cells mediating the GVL effect. Here we demonstrate that imatinib specifically downregulated DR4 and DR5 expression in cell lines and clinical samples of Ph(+) leukemia. Second-generation tyrosine kinase inhibitors (dasatinib and nilotinib) and short hairpin RNA against bcr-abl also downregulated DR4 and DR5 expression in Ph(+) leukemia cells, and transfection of bcr-abl into a Ph(-) leukemia cell line induced DR4 and DR5 expression, which was abrogated by imatinib treatment. Accordingly, Ph(+) leukemia cells that had been pretreated with imatinib showed resistance to the pro-apoptotic activity of recombinant human soluble TRAIL. These observations demonstrate that BCR-ABL is critically involved in the leukemia-specific expression of DR4 and DR5 and in the susceptibility of Ph(+) leukemia to TRAIL-mediated anti-leukemic activity, providing new insight into the mechanisms of the tumor-specific cytotoxic activities of TRAIL.

Measurement of xenon plasma properties in an ion thruster using laser Thomson scattering technique.

This paper reports on the development of a method for measuring xenon plasma properties using the laser Thomson scattering technique, for application to ion engine system design. The thresholds of photo-ionization of xenon plasma were investigated and the number density of metastable atoms, which are photo-ionized by a probe laser, was measured using laser absorption spectroscopy, for several conditions. The measured threshold energy of the probe laser using a plano-convex lens with a focal length of 200 mm was 150 mJ for a xenon mass flow rate of 20 µg/s and incident microwave power of 6 W; the probe laser energy was therefore set as 80 mJ. Electron number density was found to be (6.2 ± 0.4) × 10(17) m(-3) and electron temperature was found to be 2.2 ± 0.4 eV at a xenon mass flow rate of 20 µg/s and incident microwave power of 6 W. The threshold of the probe laser intensity against photo-ionization in a miniature xenon ion thruster is almost constant for various mass flow rates, since the ratio of population of the metastable atoms to the electron number density is little changed.

Oncogenic fusion E2A-HLF sensitizes t(17;19)-positive acute lymphoblastic leukemia to TRAIL-mediated apoptosis by upregulating the expression of death receptors.

t(17;19)-acute lymphoblastic leukemia (ALL) shows extremely poor prognosis. E2A-HLF derived from t(17;19) blocks apoptosis induced by the intrinsic mitochondrial pathway and has a central role in leukemogenesis and chemoresistance. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is expressed on cytotoxic T cells and natural killer cells and binds with death receptors (DR4/DR5), inducing apoptosis by dual activation of intrinsic and extrinsic pathways, and TRAIL mediates the graft-versus-leukemia (GVL) effect after allogeneic stem cell transplantation (allo-SCT). We found that cell lines and patients' samples of t(17;19)-ALL expressed death receptors for TRAIL, and recombinant soluble TRAIL immediately induced apoptosis into t(17;19)-ALL cell lines. E2A-HLF induced gene expression of DR4/DR5, which was dependent on the DNA-binding and transactivation activities of E2A-HLF through the 5' upstream region of the start site at least in the DR4 gene. Introduction of E2A-HLF into non-t(17;19)-ALL cell line upregulated DR4 and DR5 expression, and sensitized to proapoptotic activity of recombinant soluble TRAIL. Finally, a newly diagnosed t(17;19)-ALL patient underwent allo-SCT immediately after induction of first complete remission, and the patient has survived without relapse for over 3-1/2 years after allo-SCT. These findings suggest that E2A-HLF sensitizes t(17;19)-ALL to the GVL effect by upregulating death receptors for TRAIL.

Fungemia due to Rhodotorula mucilaginosa after allogeneic hematopoietic stem cell transplantation.

Rhodotorula species have been increasingly recognized as emerging pathogens, particularly in immunocompromised patients. We herein report on a patient with myelodysplastic syndrome who developed fungemia due to Rhodotorula mucilaginosa after allogeneic hematopoietic stem cell transplantation (HSCT) from an unrelated donor. He developed severe acute graft-versus-host disease requiring high-dose steroids, and had serially been administered fluconazole and micafungin for the prophylaxis of fungal infection. Although several cases of Rhodotorula infection after HSCT have been reported, all of them were recipients of autologous HSCT, not allogeneic HSCT. A review of all the reported cases of Rhodotorula infection after HSCT revealed that all patients had received fluconazole or echinocandins before the onset of infection. The findings suggest that Rhodotorula species could be causative yeasts, particularly in patients receiving fluconazole or echinocandins, both of which are inactive against the species.

Ictal SPECT of thalamocortical coupling in a patient with frontal absence.

Petit mal absence has been reported with 3-Hz generalized spike-and-wave discharges induced by secondary bilateral synchrony. Absence seizure may be present in patients with frontal lobe epilepsy. The thalamic rhythmogenic mechanisms responsible for spike-and-wave discharges have been investigated, providing a better understanding of the underlying anatomico-physiological mechanisms. We report the thalamocortical coupling in a patient with frontal absence by performing synchronous ictal single photon emission computed tomography (SPECT) analysis. Ictal SPECT revealed thalamic hyperperfusion combined with ipsilateral frontal cortical hyperperfusion in the patient. Moreover, lateral indexes of cerebral blood flow in the frontal region and thalamus were higher than those from non-epileptic control subjects. Thalamocortical coupling was thus revealed by ictal SPECT. Frontal absences should be considered as a secondarily generalized epilepsy syndrome originating from the frontal regions. The thalamus may play a crucial role as a pacemaker of rhythmic electroencephalographic activities such as secondary bilateral synchronous discharges in patients with frontal absences.