Interferon-gamma is an autocrine mediator for dendritic cell maturation

Maturation of dendritic cells (DC) is critical for efficient antigen presentation and initiation of an immune response. Interferon-gamma (IFN-gamma) is an important Th1 cytokine. In this study, we investigated the role of IFN-gamma in DC maturation using either IFN-gamma receptor deficient- or IFN-gamma overexpression-models. We showed that immature DC generated in vitro from bone marrow (BM) progenitor cells produced low level of IFN-gamma. After LPS stimulation, DC produced more IFN-gamma, and IFN-gamma productions were at comparable levels among C57BL/6 mice-derived DC (C57BL/6 DC), wild-type 129 mice-derived DC (129 DC) and IFN-gamma receptor deficient 129 mice-derived DC (IFN-gammaR-/-DC). We found that IFN-gammaR-/-DC exhibited decreased expression of CD54, CD86, reduced capacity to secrete IL-1beta and IL-12p70, and impaired capacity to stimulate alloreactive T cells and to drive Th1 differentiation. Transfection of IFN-gamma gene into DC promoted DC to express higher CD40, CD54, CD80, CD86, CCR7 and I-Ab, secrete more IL-1beta and IL-12p70, and more potently activate both CD4 and CD8 T cells. These data suggest that IFN-gamma signaling pathway is important for the maturation of DC in an autocrine fashion.     

Cross-sectional analysis of clinical and environmental isolates of Pseudomonas aeruginosa: biofilm formation, virulence, and genome diversity

Chronic lung infections with Pseudomonas aeruginosa biofilms are associated with refractory and fatal pneumonia in cystic fibrosis (CF). In this study, a group of genomically diverse P. aeruginosa isolates were compared with the reference strain PAO1 to assess the roles of motility, twitching, growth rate, and overproduction of a capsular polysaccharide (alginate) in biofilm formation. In an in vitro biofilm assay system, P. aeruginosa displayed strain-specific biofilm formation that was not solely dependent on these parameters. Compared with non-CF isolates, CF isolates expressed two opposing growth modes: reduced planktonic growth versus efficient biofilm formation. Planktonic cells of CF isolates showed elevated sensitivity to hydrogen peroxide, a reactive oxygen intermediate, and decreased lung colonization in an aerosol infection mouse model. Despite having identical genomic profiles, CF sequential isolates produced different amounts of biofilm. While P. aeruginosa isolates exhibited genomic diversity, the genome size of these isolates was estimated to be 0.4 to 19% (27 to 1,184 kb) larger than that of PAO1. To identify these extra genetic materials, random amplification of polymorphic DNA was coupled with PAO1-subtractive hybridization. Three loci were found within the genomes of two CF isolates encoding one novel homolog involved in retaining a Shigella virulence plasmid (mvpTA) and two divergent genes that function in removing negative supercoiling (topA) and biosynthesis of pyoverdine (PA2402). Together, P. aeruginosa biodiversity could provide one cause for the variation of morbidity and mortality in CF. P. aeruginosa may possess undefined biofilm adhesins that are important to the development of an antibiofilm therapeutic target.     

Small intestinal organoid-derived SP cells contribute to repair of irradiation-induced skin injury

Side population (SP) cells, characterized by their ability to efflux the fluorescent dye Hoechst 33342, were isolated from the small intestine of mice. In the abdominal irradiation model, small intestinal organoid-derived SP (sioSP) cells from ROSA 26 mice were submucosally injected into the small intestinal of the irradiated C57BL/6 mice. In contrast to the control mice, mice receiving sioSP cell transplantation demonstrated far less skin injury. Most importantly, hairs in the irradiated body part of the transplanted mice almost remained black, whereas the counterpart in the control mice almost turned white. Histochemistry studies showed the donor cells gave rise to skin cells in the irradiated skin. Thus, our study demonstrated for the first time that stem cells from the small intestine can differentiate into skin cells under local cues and thus supports the theory of stem cell plasticity.     

Comparativein vitro study of the effect of contrast media on complement activity and eicosanoid content in rat blood

The study comparesin vitro effect of different contrast media on complement activity and eicosanoid content. Ionic agents (Bilignost>Iodamide>Triombrast>Hexabrix) exert pronounced complement-activating effect, while nonionic agents markedly increase blood content of arachidonic acid metabolites. The complement-activating effect of contrast media did not correlate with their ability to elevate blood content of prostaglandin F_2α and leukotrienes C₄ and B₄. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 6, pp. 637–640, June, 1998     

Molecular cloning and characterization of the 120-kilodalton protein gene of Ehrlichia canis and application of the recombinant 120-kilodalton protein for serodiagnosis of canine ehrlichiosis

The 120-kDa outer membrane protein (p120) is a potential adhesin of Ehrlichia chaffeensis, and recombinant p120 is very useful for serodiagnosis of human monocytotropic ehrlichiosis. The analogous gene of p120 in Ehrlichia canis was cloned, sequenced, and expressed. Like the E. chaffeensis p120, the E. canis p120 contains tandem repeat units. However, neither the repeat number nor the amino acid sequences in the repeats are identical in the two Ehrlichia species. The repeat units are hydrophilic and by probability analysis are predicted to be surface exposed in both species. The repeat regions of the p120s of the two species have common amino acid sequences that are predicted to be surface exposed. The overall amino acid sequence of the E. canis p120 is 30% homologous to that of E. chaffeensis p120. Protein immunoblotting demonstrated that the recombinant E. canis p120 reacted with convalescent sera from dogs with canine ehrlichiosis. These results indicate that the recombinant p120 is a potential antigen for the serodiagnosis of canine ehrlichiosis.     

Characterization of IL-4 and IL-13 signals dependent on the human IL-13 receptor alpha chain 1: redundancy of requirement of tyrosine residue for STAT3 activation

IL-4 and IL-13 are pleiotropic cytokines whose biological activities overlap with each other. IL-13 receptor alpha chain 1 (IL-13R alpha 1) is necessary for binding to IL-13, and the heterodimer composed of IL-13R alpha 1 and IL-4R alpha chain transduces IL-13 and IL-4 signals; however, the functional mapping of the intracellular domain of IL-13R alpha 1 is not fully understood. In this study, we constructed wild and mutated types of human IL-13R alpha 1, and analyzed IL-4 and IL-13 signals using an IL-13R alpha 1-transfected human B cell line. Expression of IL-13R alpha 1 evoked STAT3 activation by IL-4 and IL-13, and in stimulated human B cells, on which IL-13R alpha 1 was highly expressed, IL-4 and IL-13 induced STAT3 activation. Replacement of the two tyrosine residues completely abolished STAT3 activation, although replacing either tyrosine residue alone retained it. Furthermore, we found that the Box1 region and the C-terminal tail of IL-13R alpha 1 were critical for binding to Tyk2, and activation of Jak1, Tyk2, the insulin receptor substrate-1 and STAT6 respectively. These results suggest that STAT3 activation is involved with IL-4 and IL-13 signals in human B cells along with the activation of STAT6, and that there is a unique sequence in IL-13R alpha 1 to activate STAT3.     

Critical spectral regions for vowel identification

The first two formant frequencies (F1 and F2) are the cues important for vowel identification. In the categorization of the naturally spoken vowels, however, there are overlaps among the vowels in the F1 and F2 plane. The fundamental frequency (F0), the third formant frequency (F3) and the spectral envelope have been proposed as additional cues. In the present study, to investigate the spectral regions essential for the vowel identification, untrained subjects performed the forced-choice identification task in response to Japanese isolated vowels (/a, o, u, e, i/), in which some spectral regions were deleted. Minimum spectral regions needed for correct vowel identification were the two regions including F1 and F2 (the first and fourth in the quadrisected F1-F2 regions in Bark scale). This was true even when phonetically different vowels had a similar combination of F1 and F2 frequency components. F0 and F3 cues were not necessarily needed. It is concluded that the relative importance in the spectral region is not equivalent, but weighted on the two critical spectral regions. The auditory system may identify the vowels by analyzing the information of the spectral shapes and the formant frequencies (F1 and F2) in these critical spectral regions.     

Analysing collimator structure effects in head-scatter calculations for IMRT class fields using scatter raytracing

The frequent blocking of the irradiated volume in intensity modulated radiation therapy (IMRT) makes the head-scatter fraction of the incident photon fluence more significant than that in conventional therapy with open fields. On the other hand. certain collimator configurations block scatter photons directed to a given observation point while allowing primary photons to be transmitted. The 'anomalous blocking' makes the primary field a poor indicator of the scatter fluence. Since large MU-to-cGy ratios in IMRT can magnify head-scatter uncertainties, it becomes necessary to accurately model both the effective scatter source and the collimator structure that limits the scatter reaching the irradiated volume. First we obtain a dual-source model, using a Taylor series expansion to derive the effective scatter source distribution from the data measured for the Elekta SL20 linac equipped with a multi-leaf collimator (MLC). Then, using a raytracing algorithm, we calculate the transmission of scatter rays from the effective scatter source plane to points in the patient plane. The method can account for the anomalous blocking of scatter by the MLC leaves and the backup diaphragms. For a variety of collimator settings tested, the calculations agree with measurements to an accuracy of 0.002psi10 x 10, where psi10 x 10 is the total (primary + scatter) photon fluence of an open 10 x 10 cm2 field for the same MU delivered. Although the significance of collimator structure in IMRT depends strongly on fields shapes employed for the delivery, potential cumulative errors on the order of a few per cent can be avoided in fluence calculations if the proposed method is used.     

数字化大鼠动脉血管系统三维模型的建立

采用含造影剂及显色剂的填充剂对成年SD大鼠动脉血管系统进行灌注,并借助数字X射线成像设备对灌注效果进行实时监测,通过断层解剖成像系统获取切削间距为100 μm的二维断面解剖数据集(图像分辨率为4917×3446×24 bit,共1 464张),最后利用Visual C 结合可视化工具包编程实现数据集的动脉分割及三维可视化,得到数字化SD大鼠动脉血管系统的三维模型.该模型能提供大鼠动脉血管系统的空间结构信息,为实验大鼠血管系统的研究提供了更为准确可靠的形态学参考.     

Paternal mosaicism and hereditary angioedema in a Taiwanese family.

BACKGROUND: Hereditary angioedema (HAE) is a rare disorder characterized by recurrent attacks of localized subcutaneous or submucosal edema. It is inherited in an autosomal dominant fashion and caused by a deficiency of C1 inhibitor (C1 INH). Most patients with HAE have an absolute deficiency of C1 INH (type I HAE), whereas the rest (approximately 15%) synthesize a dysfunctional C1 INH protein (type II HAE). Mosaicism is rare in HAE. OBJECTIVE: To describe the clinical manifestations, laboratory findings, and molecular genetic studies in a Taiwanese family with type I HAE with paternal mosaicism. METHODS: A family that included a 34-year-old man (index patient) and his 25-year-old brother who both had recurrent peripheral angioedema was evaluated. A younger sister had died of an unexplained cause at 18 years of age. We analyzed blood levels of C3, C4, and C1 INH and sequenced the SERPING] (C1NH) gene that codes for C1 INH in 5 family members, including the parents and 3 brothers. RESULTS: The 4 men in the family had a novel mutation c.3_73del, p.N1fsX34 in exon 3 of the C1INH gene, resulting in C1 INH deficiency. Although the father carried this mutant gene, he had normal serum levels of C1 INH. Based on quantitative analysis of allele dosage by DNA fragment analysis (GeneScan), the father was determined to have genetic mosaicism. CONCLUSION: Parental mosaicism is a possible explanation for normal C1 INH plasma concentrations in both parents despite clinically apparent HAE in the children.