Activation of the NLRP3 and AIM2 inflammasomes in a mouse model of Schistosoma mansoni infection.

Schistosomiasis is an inflammatory disease that occurs when schistosome species eggs are deposited in the liver, resulting in fibrosis and portal hypertension. Schistosomes can interact with host inflammasomes to elicit host immune responses, leading to mitochondrial damage, generation of high levels of reactive oxygen species (ROS) and activation of apoptosis during inflammation. This study aims to examine whether ROS and NF-κB (p65) expression elicited other types of inflammasome activation in Schistosoma mansoni-infected mouse livers. We examine the relationship between inflammasome activation, mitochondrial damage and ROS production in mouse livers infected with S. mansoni. We demonstrate a significant release of ROS and superoxides and increased NF-κB (p65) in S. mansoni-infected mouse livers. Moreover, activation of the NLRP3 and AIM2 inflammasomes was triggered by S. mansoni infection. Stimulation of HuH-7 hepatocellular carcinoma cells with soluble egg antigen induced activation of the AIM2 inflammasome pathway. In this study, we demonstrate that S. mansoni infection promotes both NLRP3 and AIM2 inflammasome activation.

The role of chunking in drawing Rey complex figure.

The study investigated the effects of chunking and perceptual patterns that guide the drawings of Rey complex figure. Ten adult participants (M age=22.2 yr., SD=4.1) reproduced a single stimulus in four drawing modes including delayed recall, tracing, copying, and immediate recall across 10 sessions producing a total of 400 trials. It was hypothesized that the effect of chunking is most obvious in the free recall tasks than in the tracing or copying tasks. Measures such as pauses, patterns of drawings, and transitions among patterns of drawings suggested that participants used chunking to aid rapid learning of the diagram. The analysis of the participants' sequence of chunk production further revealed that they used a spatial schema to organize the chunks. Findings from this study provide additional evidence to support prior studies that claim graphical information is hierarchically organized.

Evaluating the potential of a new isotope-labelled glyco-ligand for estimating the remnant liver function of schistosoma-infected mice.

A new glyco-derivative compound (OCTAM) was developed and labelled with isotope to form (188) Re-OCTAM as a candidate nuclear medicine imaging agent for testing the liver function. We evaluated the potential of isotope-labelled OCTAM for estimating the remnant liver function in vitro and in vivo schistosoma-infected mice. The affinity of OCTAM to liver asialoglycoprotein receptors (ASGPR) was assessed by competitive inhibition assay in vitro. In vivo assessments were performed to score the remnant liver function in mice at different schistosomal infection stages. OCTAM binds specifically to ASGPR and showed competitive inhibition of anti-ASGPR antibody binding to hepatocytes, and was higher than that of other galactosyl ligands. Micro-SPECT/CT images of uninfected mice revealed strong liver uptake. Quantified serial images of mice infected for 9, 12 and 18 weeks showed delayed liver uptake, and the retention of uptake was inversely correlated with stage and grade of schistosoma infection. Pathological and biochemical analysis demonstrated that gradually accumulating liver injury caused by infection significantly influenced uptake of (188) Re-OCTAM. Hepatic ASGPR expression diminished only in the chronic infection stage. This study demonstrated that the isotope-labelled OCTAM could accumulate in the liver, might have potential as an imaging agent for in vivo hepatic function evaluation of schistosomiasis.

Quasiparticle dynamics and phonon softening in FeSe superconductors.

Quasiparticle dynamics of FeSe single crystals revealed by dual-color transient reflectivity measurements (ΔR/R) provides unprecedented information on Fe-based superconductors. The amplitude of the fast component in ΔR/R clearly gives a competing scenario between spin fluctuations and superconductivity. Together with the transport measurements, the relaxation time analysis further exhibits anomalous changes at 90 and 230 K. The former manifests a structure phase transition as well as the associated phonon softening. The latter suggests a previously overlooked phase transition or crossover in FeSe. The electron-phonon coupling constant λ is found to be 0.16, identical to the value of theoretical calculations. Such a small λ demonstrates an unconventional origin of superconductivity in FeSe.

Triggering receptor expressed on myeloid cells (TREM)-1 participates in Schistosoma mansoni inflammatory responses.

Inflammatory responses to microbial products are amplified by a pathway mediated by triggering a receptor expressed on the myeloid cells (TREM)-1. Relatively a few studies have been performed to investigate the role of TREM-1 in macrophage activation in response to parasitic infection. In this study, we delineate the role of the innate immunoreceptor TREM-1 in the parasite Schistosoma mansoni infection model from early to late (chronic) phases of infection. Flow cytometry analysis revealed gradual increase in the production of TREM-1 protein on CD11b(+) myeloid cells, with maximum production at 5 weeks p.i. Similar results in the pattern of TREM-1 mRNA expressions in splenic CD11b(+) cells from infected mice were obtained by real-time PCR. However, unlike in spleen, the TREM-1 mRNA expression in liver tissue showed no significant increase throughout the infection, including periods of maximum production of parasite eggs. Administration of schistosoma egg homogenate antigen to stimulate J774A.1 cells inhibited TREM-1 expression on the surface, indicating that some substances of the Schistosma eggs may inhibit the expression of TREM-1 on macrophages, lowering the macrophage-mediated inflammatory response of infected hosts.

A role for lipid rafts in B cell antigen receptor signaling and antigen targeting.

The B cell antigen receptor (BCR) serves both to initiate signal transduction cascades and to target antigen for processing and presentation by MHC class II molecules. How these two BCR functions are coordinated is not known. Recently, sphingolipid- and cholesterol-rich plasma membrane lipid microdomains, termed lipid rafts, have been identified and proposed to function as platforms for both receptor signaling and membrane trafficking. Here we show that upon cross-linking, the BCR rapidly translocates into ganglioside G(M1)-enriched lipid rafts that contain the Src family kinase Lyn and exclude the phosphatase CD45R. Both Igalpha and Lyn in the lipid rafts become phosphorylated, and subsequently the BCR and a portion of G(M1) are targeted to the class II peptide loading compartment. Entry into lipid rafts, however, is not sufficient for targeting to the antigen processing compartments, as a mutant surface Ig containing a deletion of the cytoplasmic domain is constitutively present in rafts but when cross-linked does not internalize to the antigen processing compartment. Taken together, these results provide evidence for a role for lipid rafts in the initial steps of BCR signaling and antigen targeting.

Spatial and temporal dynamics of DNA replication sites in mammalian cells.

Fluorescence microscopic analysis of newly replicated DNA has revealed discrete granular sites of replication (RS). The average size and number of replication sites from early to mid S-phase suggest that each RS contains numerous replicons clustered together. We are using fluorescence laser scanning confocal microscopy in conjunction with multidimensional image analysis to gain more precise information about RS and their spatial-temporal dynamics. Using a newly improved imaging segmentation program, we report an average of approximately 1,100 RS after a 5-min pulse labeling of 3T3 mouse fibroblast cells in early S-phase. Pulse-chase-pulse double labeling experiments reveal that RS take approximately 45 min to complete replication. Appropriate calculations suggest that each RS contains an average of 1 mbp of DNA or approximately 6 average-sized replicons. Double pulse-double chase experiments demonstrate that the DNA sequences replicated at individual RS are precisely maintained temporally and spatially as the cell progresses through the cell cycle and into subsequent generations. By labeling replicated DNA at the G1/S borders for two consecutive cell generations, we show that the DNA synthesized at early S-phase is replicated at the same time and sites in the next round of replication.

Stable high-order molecular sandwiches: hydrocarbon polyanion pairs with multiple lithium ions inside and out.

Stable ten-component sandwich compounds have been characterized in which four lithium ions reside between two tetraanions derived from corannulene or its alkyl-substituted derivatives and four additional lithium ions decorate the exterior. In tetrahydrofuran solution, the four lithium ions inside the sandwich can exchange environments with the four external lithium atoms, but the two tetraanion decks of the sandwich never separate from one another on the time scale of nuclear magnetic resonance. Theoretical calculations point to a "stacked bowl" conformation and a low energy barrier for synchronous double inversion of the tetraanion bowls in the solvated sandwich compounds.

Potential role of the inactivated X chromosome in ovarian epithelial tumor development.

BACKGROUND: Ovarian epithelial tumors can be divided into subcategories often regarded as different stages of neoplastic transformation. Cystadenomas belong to the least aggressive subgroup and are noninvasive and nonmetastatic. Ovarian tumors of low malignant potential (LMP) are intermediate between cystadenomas and carcinomas and show markedly reduced invasive and metastatic abilities. Invasion and metastasis are the hallmarks of carcinomas, which constitute the most aggressive subgroup and can be further subdivided into different grades. PURPOSE: We performed comparative allelotype analyses of ovarian cystadenomas, LMP tumors, and carcinomas, reasoning that such analyses could provide clues about the molecular determinants of their phenotypic differences. Because we realized that allelic losses involving the X chromosome might be associated with LMP tumor development, we determined whether such losses were interstitial and whether they involved the active or the inactive X chromosome. METHODS: Frequencies of loss of heterozygosity (LOH) at specific loci in every chromosomal arm were determined in 16 ovarian cystadenomas, 23 ovarian LMP tumors, 15 low-grade ovarian carcinomas, and 35 high-grade ovarian carcinomas by use of either the polymerase chain reaction (PCR) or Southern blot analyses. We took advantage of the fact that DNA methylation is an important mechanism of X-chromosome inactivation to determine whether losses involving the X chromosome were in the active or the inactive copy. We analyzed the methylation status of retained alleles on the X chromosome by determining whether they could be amplified by PCR after digestion with the methylation-sensitive restriction endonuclease Hpa II. RESULTS: High-grade carcinomas contained frequent(>50%) LOH in four autosomal chromosome arms, i.e., 6q, 13q, 17p, and 17q. Except for 13q, these same chromosomal arms showed frequent LOH in low-grade carcinomas. LOH in autosomal chromosomes was comparatively rare in LMP tumors and was absent in cystadenomas. In contrast, half (eight of 16) of LMP tumors informative for a locus in the proximal portion of chromosome Xq showed LOH at that locus. These losses were the result of interstitial deletions in six of the eight cases and involved the inactive copy of the X chromosome exclusively. Similar losses in the X chromosome were not seen in either cystadenomas or low-grade carcinomas. CONCLUSIONS AND IMPLICATIONS: LOH at multiple loci is associated with the development of ovarian carcinomas but not with the development of cystadenomas and LMP tumors. However, the integrity of a locus in chromosome Xq that possibly escapes X-chromosome inactivation is important for the control of LMP tumor development. The fact that this locus does not appear to be involved in the genesis of low-grade carcinomas suggests that LMP tumors are not precursors of such carcinomas.

Allelic loss and microsatellite alterations of chromosome 3p14.2 are more frequent in recurrent cervical dysplasias.

Epidemiological studies have documented the unpredictable clinical progression or recurrence of cervical dysplasia. Recent studies have shown several molecular changes in cervical cancers and their associated dysplasia. We conducted molecular analyses on a retrospectively ascertained cohort of recurrent and nonrecurrent cervical dysplasia cases in an attempt to define molecular biomarkers to predict progressive or recurrent disease. Cases were chosen if long-term follow-up (3-5 years after conization) and biopsy confirmation were available. Paraffin-embedded, postconization cervical tissues from 19 recurrent and 18 nonrecurrent dysplasias were analyzed. Human papillomavirus (HPV) was identified by PCR for general and type-specific (HPV-16 and HPV-18) primers. Allelotyping analysis was performed by multiplex PCR using a panel of 16 microsatellite markers targeting putative tumor suppressor gene regions on chromosomes 3p, 5p, 6p, 9p, 11q, and 17p. The overall rate of HPV infection was similar in both groups. In the allelotyping analysis, loss of heterozygosity at the fragile histidine triad region in 3p14.2 was significantly higher in the recurrent group than in the nonrecurrent group (P = 0.005). Furthermore, microsatellite alterations (MAs) were more frequent in the recurrent group (mean MA index, 0.254) as compared with the nonrecurrent group (mean MA index, 0.085; P = 0.0025). These findings suggest that HPV status alone does not predict recurrence and that loss of heterozygos. ity at the fragile histidine triad region may represent a potential biomarker in predicting recurrence. Frequent MAs in the recurrent group may represent an underlying genomic instability that creates susceptibility for allelic loss, thus increasing the risk for recurrence or progression.

A role for MHC class II antigen processing in B cell development.

For mature B cells, the encounter with foreign antigen results in the selective expansion of the cells and their differentiation into antibody secreting cells or memory B cells. The response of mature B cells to antigen requires not only antigen binding to and signaling through the B cell antigen receptor (BCR) but also the processing and presentation of the BCR bound antigen to helper T cells. Thus, in mature B cells, the ability to process and present antigen to helper T cells plays a critical role in determining the outcome of antigen encounter. In immature B cells, the binding of antigen results in negative selection of the B cell, inducing apoptosis, anergy or receptor editing. Negative selection of immature B cells requires antigen induced signaling through the BCR, analogous to the signaling function of the BCR in mature B cells. However, the role of class II antigen processing and presentation in immature B cells is less well understood. Current evidence indicates that the ability to process and present antigen bound to the BCR is a late acquisition of developing B cells, suggesting that during negative selection B cells may not present BCR bound antigen and interact with helper T cells. However, the expression of class II molecules is an early acquisition of B cells and recent evidence indicates that the expression of class II molecules early in development is required for the generation of long lived mature B cells. Here we review our current understanding of the processing and presentation of antigen by mature B cells and the role for antigen processing and class II expression during B cell development.

Unexpectedly large dose rate dependent output from a linear accelerator.

During our routine calibration of a Varian Clinac-20 linear accelerator, the absorbed dose for a fixed monitor unit (mu) was found to decrease with increasing dose rate. Between dose rates of 100 and 500 mu/min, there was up to 20% difference in absorbed dose for a 20-MeV electron beam. The cause of this problem was a failure in the electronics circuit of an integrating board. This paper presents our analysis of the problem and suggests a possible means of isolating such a failure to warn technologists, physicists, and engineers.

A derivative-free noncircular fan-beam reconstruction formula.

In order to perform fan-beam reconstruction using projection data collected from a noncircular scanning locus, existing noncircular fan-beam formulas require a derivative of the scanning locus with respect to the rotation angle. A derivative-free noncircular fan-beam reconstruction formula that is based on a geometrical explanation of the circular equispatial fan-beam reconstruction formula is obtained here. A mathematical proof is then provided under the conditions that the source-to-origin distance is symmetric with respect to the origin of the reconstruction coordinate system, is differentiable almost everywhere, and does not change too fast with respect to the rotation angle. The derivative-free noncircular fan-beam reconstruction formula is the same as the circular one, except that the source-to-origin distance is a function of the rotation angle. A typical simulation result for the noncircular fan-beam formula is given.

Half-scan cone-beam x-ray microtomography formula.

An x-ray shadow projection microtomographic system using a scannable point source is under development at AMIL-ARTS, SUNY at Buffalo. To overcome the limitations of the commonly used Feldkamp's cone-beam reconstruction formula, we have developed a generalized Feldkamp-type cone-beam reconstruction formula. In the generalized Feldkamp-type cone-beam reconstruction, a scanning locus can be either planar or helix-like, and a transaxial slice is reconstructed using projection data collected from a 360 degrees angular range (full scan). In this paper, the full-scan cone-beam formula is modified to require only projection data of approximate 180 degrees plus two fan-angles (half scan). First, a half-scan derivative-free noncircular fan-beam reconstruction formula is formulated. Then, a half-scan cone-beam reconstruction formula is derived as an extension of the half-scan fan-beam reconstruction formula using Feldkamp's procedure. Typical numerical simulation results are given for both half-scan formulae. Compared with the full-scan cone-beam formula, the half-scan cone-beam formula reduces the involved angular range of projection data and allows better longitudinal/temporal resolution.

Multiphoton confocal microscopy using a femtosecond Cr:forsterite laser.

With its output wavelength covering the infrared penetrating window of most biological tissues at 1,200-1,250 nm, the femtosecond Cr:forsterite laser shows high potential to serve as an excellent excitation source for the multiphoton fluorescence microscope. Its high output power, short optical pulse width, high stability, and low dispersion in fibers make it a perfect replacement for the currently widely used Ti:sapphire laser. In this paper, we study the capability of using a femtosecond Cr:forsterite laser in multiphoton scanning microscopy. We have performed the multiphoton excited photoluminescence spectrum measurement on several commonly used bioprobes using the 1,230 nm femtosecond pulses from a Cr:forsterite laser. Efficient fluorescence can be easily observed in these bioprobes through two-photon or three-photon excitation processes. These results will assist in the selection of dichroic beam splitter and band pass filters in a multiphoton microscopic system. We have also performed the autofluorescence spectrum measurement from chlorophylls in live leaves of the plant Arabidopsis thaliana excited by 1,230 nm femtosecond pulses from the Cr:forsterite laser. Bright luminescence from chlorophyll, centered at 673 and 728 nm, respectively, can be easily observed. Taking advantage of the bright two-photon photoluminescence from chlorophyll, we demonstrated the two-photon scanning paradermal and cross-sectional images of palisade mesophyll cells in live leaves of Arabidopsis thaliana.

Three-dimensional laser scanning two-photon fluorescence confocal microscopy of polymer materials using a new, efficient upconverting fluorophore.

Three-dimensional confocal imaging of polymer samples was achieved by the use of two-photon excited fluorescence in both positive and negative contrast modes. The fluorophore was a new and highly efficient two-photon induced upconverter, resulting in improved signal strength at low pumping power. Because of the relatively long wavelength of the excitation source (798 nm from a mode-locked Ti:Sapphire laser), this technique shows a larger penetration depth into the samples than provided by conventional single-photon fluorescence confocal microscopy. Single-photon and two-photon images of the same area of each sample show significant differences. The results suggest the possibility of using two-photon confocal microscopy, in conjunction with highly efficient fluorophores, as a tool to study the surface, interface, and fracture in material science applications.

Visualization and interactive exploration of multidimensional confocal images.

A confocal image analysis system is developed for automatic extraction of surface representation of biological structures. A visualization system is also developed to manipulate these surface representations and to obtain morphometrical parameters and provides a powerful tool for biomedical research such as microstructural characterization, morphogenesis, cell differentiation, tissue organization, and embryo development.

Monitor unit calculations for breast or chest wall treatments.

Tangential breast fields always "flash" beyond the surface of the patient. Since the portion of the beam that is in air does not contribute scatter, external beam treatment planning computers that utilize stored beam data can lead to dose errors of up to 10%. These errors can be reduced by using an irregular field calculation program to adjust the monitor units to account for the loss of scatter.

Confocal and multi-photon microscopy of dental hard tissues and biomaterials.

Confocal microscopy is a technique that can be used both in the clinic and the high-resolution microscopy suite. This form of optical microscopy enables high-resolution images to be made of samples with minimum requirements for specimen preparation. Images may be made of either reflections from the sample surface or, if an immersion medium is used to optically couple the objective lens, then sub-surface images can be produced of reflective or fluorescent structures within semi transparent materials such as cells and dental hard tissues. These images are like optical sections, giving thin (> 0.35 microm) slices up to 200 microm below the surface of a mineralized tissue. The technique generates significant improvements in resolution, lying somewhere between that of conventional light microscopy and TEM/SEM. Instruments that work at video-rate allow high-speed events to be examined, such as in vivo clinical studies, cutting of dental tissues and fracture of adhesive interfaces. New dyes offer many exciting prospects for labeling changes in chemical composition in materials or biological tissues, while new imaging techniques such as multi-photon laser excitation of dyes give the potential of greater depth penetration and improved resolution. As with all new techniques the inexperienced should be aware of some of the artifacts inherent to the system. However, the widespread availability of conventional confocal microscopes should give ample opportunity for dental researchers to capitalize on this new technology.

Aortocoronary bypass surgery and chronic renal failure: case report.

A successful case of aortocoronary bypass operation in a patient with chronic renal failure managed by home haemodialysis and being considered for renal transplantation is described.