Near-infrared quantum dots for deep tissue imaging

Developments in nanotechnology have paved the way for the early detection, treatment, and prevention of several tumors which affect mankind. In the past few years, near-infrared (NIR) fluorescence imaging techniques have emerged that enable the in vivo imaging of physiological, metabolic, and molecular function. The NIR window, also known as the diagnostic window (700-900 nm), can be explored for sensitive detection techniques. Nanoparticles, particularly semiconductor quantum dots (QDs), can be utilized for the purpose of optical imaging. These semiconductor QDs possess novel electronic, optical, magnetic, and structural properties which are quite different from those of bulk materials. NIR QDs with these unique properties can be utilized as contrast agents for optical imaging, particularly for deep tissue imaging. Deep tissue imaging provides more information about the pathological status of the disease, which makes the treatment more effective and efficient. In this review we highlight the importance of NIR QDs as probes for optical imaging. We describe the different types of NIR QDs, their synthesis, and their application for deep tissue imaging along with recently developed self-illuminating NIR QDs.

Rapid current ramp-up by cyclotron-driving electrons beyond runaway velocity

The toroidal current has been rapidly ramped-up after the formation of an initial closed flux surface in an electron cyclotron heated discharge in the low aspect ratio torus experiment device. A current carrying fast electron tail is developed well beyond the runaway velocity against the reverse voltage from self-induction, suggesting a forward driving force on the tail by the cyclotron absorption of high N(parallel) electron Bernstein waves.

Periodontitis-associated up-regulation of systemic inflammatory mediator level may increase the risk of coronary heart disease

BACKGROUND AND OBJECTIVE

Although an elevation in the concentration of high-sensitivity C-reactive protein (hs-CRP) as a result of periodontal infection may account for an increased risk of developing coronary heart disease (CHD), the effect of periodontal infection on the level of hs-CRP in an otherwise healthy Japanese population has not yet been reported. The aim of the present study was to confirm, on a larger scale, our previous pilot study findings that both chronic periodontitis and subsequent periodontal treatment alter the serum levels of C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha).

MATERIAL AND METHODS

The concentrations of serum hs-CRP, IL-6 and TNF-alpha were measured in 78 periodontitis patients at baseline and at re-assessment, and in 40 periodontally healthy subjects at the time of examination.

RESULTS

The concentrations of hs-CRP and IL-6 in the sera of periodontitis patients were significantly higher than those in control subjects. By contrast, the concentration of TNF-alpha was significantly lower in periodontitis patients than in control subjects. Whereas periodontal treatment decreased the levels of serum hs-CRP and IL-6, no such effect was observed for TNF-alpha. When the patients were subdivided into four groups according to their initial concentration of hs-CRP, only the CRP and IL-6 concentrations of the highest quartile group showed a significant reduction following periodontal treatment. No significant difference in the initial clinical parameters was observed in any quartile.

CONCLUSION

Although periodontal infection does affect the concentration of hs-CRP and IL-6 in serum, a subgroup of patients exist who are highly susceptible to an increased risk of CHD associated with periodontitis, suggesting that there may be subjects who have an elevated risk of CHD independent of susceptibility to periodontal tissue destruction per se.

Blood Compatibility of Surface Modified Poly(ethylene terephthalate) (PET) by Plasma Polymerized Acetobromo-α-D-glucose

Poly (ethylene terephthalate) (PET) was surface modified by plasma polymerization of acetobromo-α-D-glucose (ABG) at different radio frequency (RF) powers. Plasma polymerization was carried out by vaporizing ABG in the powder form by heating at 135°C. Surface modification resulted in improved hydrophilicity and smoothness of the surface especially at low RF powers (30—50 W), but at high RF powers, the surface was found to be etched and the hydrophilicity decreased as evidenced by atomic force microscopy (AFM) and contact angle measurements. The plasma polymerized ABG film was found to be extensively cross-linked as evidenced by its insolubility in water. Infra red (IR) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the plasma polymerized ABG films. IR studies revealed that at lower RF powers, polymerization was taking place mainly by breaking up of acetoxy group while retaining the ring structures to a major extent during the polymerization process whereas at high RF powers, the rupture of ring structures was indicated. XPS indicated a reduction in the percentage of oxygen in the polymers going from low to high RF powers suggestive of complete destruction of the acetoxy group at high RF powers. Cross-cut tests showed excellent adhesive properties of the plasma polymerized ABG films onto PET. Static platelet adhesion tests using platelet rich human plasma showed significantly reduced adhesion of platelets onto modified PET surface as evidenced by scanning electron microscopy. Polymerization of glucose and its derivatives using RF plasma has not been reported so far and the preliminary results reported in this study shows that this could be an interesting approach in the surface modification of biomaterials.

Modified ELISPOT assay may predict T-cell hyporesponsiveness to non-inherited maternal antigens

Clinical reports have suggested the existence of immunological tolerance to noninherited maternal antigens (NIMA) in human leukocyte antigen (HLA) mismatched allogeneic stem cell transplantation (allo-SCT). We studied the T-cell reactivity using IFN-gamma enzyme-linked immunospot (ELISPOT) assay in three HLA fully matched allo-SCT cases and one healthy volunteer family case. In HLA fully matched allo-SCT cases, ELISPOT assay could detect the hyporesponsiveness of T cells from donors to the B cells from recipients. Moreover, ELISPOT assay showed that the T cells from an individual responded to B cell from his mother significantly weakly than those from an unrelated HLA-haploidentical individual. These observations suggest that our IFN-gamma ELISPOT assay-based method may predict the presence of immunological tolerance to NIMA.

Characterization of monoclonal immunoglobulin a and g against shiga toxin binding subunits produced by intranasal immunization

Immunoglobulin A (IgA) is considered to play a major role in protection of the mucosal surface. However, its immunological and biological properties have not been extensively studied because the production of IgA class monoclonal antibodies (mAbs) is difficult. We compared the properties of IgA and IgG mAbs against Shiga toxin B subunits (Stx1B). These mAbs were secreted from hybridomas that had been produced from mice after intranasal immunization with recombinant Stx1B and cholera toxin. The dose response curves for the binding of the IgA (clone G2G7) and IgG (clone D11C6) mAbs to immobilized Stx1B were similar, as revealed on ELISA. The majority of the IgA mAb formed dimers while the IgG mAb was monomeric, as judged by immunoblot analysis. The IgG mAb completely inhibited the binding of Stx1B to Burkitt's lymphoma cell line Ramos, while the inhibition by the IgA mAb was only partial. The IgG mAb was able to neutralize the cytotoxicity of Stx1 holotoxin towards Vero cells, whereas the IgA mAb was not. The binding affinity of each binding site was compared by means of surface plasmon resonance analysis involving a capture method, with which the binding of soluble Stx1B to immobilized mAb was detected. The association rate was similar but the dissociation rate was twofold faster in the case of the IgA mAb, resulting in twofold higher affinity of the IgG mAb. These results suggest that one can obtain high affinity IgA mAb but toxin neutralization is another challenge as to therapeutic antibodies of the IgA class.

The Bcr-Abl kinase inhibitor INNO-406 induces autophagy and different modes of cell death execution in Bcr-Abl-positive leukemias

Bcr-Abl tyrosine kinase (TK) inhibitors are promising therapeutic agents for Bcr-Abl-positive (Bcr-Abl(+)) leukemias. Although they are known to promote caspase-mediated apoptosis, it remains unclear whether caspase-independent cell death-inducing mechanisms are also triggered. Here we demonstrated that INNO-406, a second-generation Bcr-Abl TK inhibitor, induces programmed cell death (PCD) in chronic myelogenous leukemia (CML) cell lines through both caspase-mediated and caspase-independent pathways. The latter pathways include caspase-independent apoptosis (CIA) and necrosis-like cell death (CIND), and the cell lines varied regarding which mechanism was elicited upon INNO-406 treatment. We also observed that the propensity toward CIA or CIND in cells was strongly associated with cellular dependency on apoptosome-mediated caspase activity. Cells that undergo CIND have a high apoptosome activity potential whereas cells that undergo CIA tend to have a lower potential. Moreover, we found that INNO-406 promotes autophagy. When autophagy was inhibited with chloroquine or gene knockdown of beclin1 by shRNA, INNO-406-induced cell death was enhanced, which indicates that the autophagic response of the tumor cells is protective. These findings suggest new insights into the biology and therapy of Bcr-Abl(+) leukemias.

ATF-2 controls transcription of Maspin and GADD45α genes independently from p53 to suppress mammary tumors

The activating transcription factor, ATF-2, is a target of p38 and JNK that are involved in stress-induced apoptosis. Heterozygous Atf-2 mutant (Atf-2+/-) mice are highly prone to mammary tumors. The apoptosis-regulated gene GADD45alpha and the breast cancer suppressor gene Maspin, both of which are known to be p53 target genes, are downregulated in the mammary tumors arisen in Atf-2+/- mice. Here, we have analysed how ATF-2 controls the transcription of GADD45alpha and Maspin. ATF-2 and p53 independently activate the GADD45alpha transcription. ATF-2 does not directly bind to the GADD45alpha promoter; instead, it is recruited via Oct-1 and NF-I. ATF-2 simultaneously binds to Oct-1, NF-I and breast cancer suppressor BRCA1 to activate transcription. With regard to Maspin, ATF-2 and p53 directly bind to different sites in the Maspin promoter to independently activate its transcription. Consistent with the observation that ATF-2 and p53 independently activate the transcription of Maspin and GADD45alpha is that the loss of one copy of p53 shortened the period required for mammary tumor development in Atf-2+/- mice. These studies suggest the functional link between the ATF-2 and the two tumor suppressors BRCA1 and p53.

Apoptosis-based dual molecular targeting by INNO-406, a second-generation Bcr-Abl inhibitor, and ABT-737, an inhibitor of antiapoptotic Bcl-2 proteins, against Bcr-Abl-positive leukemia

Bcr-Abl is the cause of Philadelphia-positive (Ph(+)) leukemias and also constitutes their principal therapeutic target, as exemplified by dramatic effects of imatinib mesylate. However, mono-targeting of Bcr-Abl does not always achieve complete leukemia eradication, and additional strategies those enable complete elimination of leukemic cells are desired to develop. Here we demonstrate that INNO-406, a much more active Bcr-Abl tyrosine kinase inhibitor than imatinib, augments the activities of several proapoptotic Bcl-2 homology (BH)3-only proteins (Bim, Bad, Bmf and Bik) and induces apoptosis in Ph(+) leukemia cells via Bcl-2 family-regulated intrinsic apoptosis pathway. ABT-737, an inhibitor of antiapoptotic Bcl-2 and Bcl-X(L), greatly enhanced the apoptosis by INNO-406, even in INNO-406-less sensitive cells with Bcr-Abl point mutations except T315I mutation. In contrast, co-treatment with INNO-406 and other pharmacologic inducers of those BH3-only proteins, such as 17-allylaminogeldanamycin, an heat shock protein-90 inhibitor, or PS-341, a proteasome inhibitor, did not further increase the BH3-only protein levels or sensitize leukemic cells to INNO-406-induced apoptosis, suggesting a limit to how much expression levels of BH3-only proteins can be increased by anticancer agents. Thus, double-barrelled molecular targeting for Bcr-Abl-driven oncogenic signaling and the cell protection by antiapoptotic Bcl-2 family proteins may be the rational therapeutic approach for eradicating Ph(+) leukemic cells.

Rapid and accurate measurement of anti-A/B IgG antibody in ABO-unmatched living donor liver transplantation by surface plasmon resonance

High anti-blood group A or B (anti-A/B) immunoglobulin G (IgG) haemagglutination titres are associated with poor graft survival in ABO-unmatched liver transplantation. We have previously reported that the surface plasmon resonance (SPR) method can be used to measure anti-A/B IgG levels in the plasma very quickly and quantitatively. The aim of this study was to brush up this SPR method. The anti-A/B IgG antibodies (Abs) were purified from the plasma of healthy volunteers by affinity chromatography and used to establish standard curves for the SPR and flow cytometry (FCM) methods. The haemagglutination test tube (TT), FCM and SPR methods were then used to measure the changes over time in the anti-A/B IgG titres of 25 ABO-unmatched living donor liver transplantation (LDLT) recipients. The standard curve permitted the SPR values for the anti-A/B IgG titres to be expressed in microg mL(-1) units. The SPR measurements of the anti-A/B IgG levels in the LDLT recipients correlated very well with the FCM values, whereas the TT values correlated poorly with either method. Furthermore, the SPR method accurately detected the effects of plasma exchange. In conclusion, the SPR method is an accurate, time- and labour-saving method for measuring anti-A/B IgG titres that can be easily standardized.

Combined effects of a third-generation bisphosphonate, zoledronic acid with other anticancer agents against murine osteosarcoma

Bisphosphonates (BPs) are widely used to treat bone diseases and also appear to possess direct antitumour activity. We have previously reported that third-generation BPs such as zoledronic acid (ZOL) and minodronic acid (YM529) synergistically augment the effects of anticancer agents in various cancer cells. Recently, we have also reported the antitumour effects of YM529 on murine osteosarcoma cells. As YM529 has not been clinically available, we herein focused on the anti-osteosarcoma effects of ZOL which is clinically available. In addition to ZOL alone, we evaluated the concurrent or sequential combined effects of ZOL with other anticancer agents against murine osteosarcoma cell lines. ZOL showed almost same anti-osteosarcoma activity compared with YM529 and more sensitive growth inhibitory effects against osteosarcoma cells than normal cells. Moreover, ZOL acted synergistically in vitro when administered concurrently with paclitaxel (PAC) or gemcitabine (GEM), not only in wild-type osteosarcoma cells but also in P-glycoprotein (P-gp)-overexpressing osteosarcoma cells, which were much less sensitive against each anticancer agent. Furthermore, 24 h of ZOL pretreatment significantly augmented the sensitivity of doxorubicin (DOX), PAC or GEM against osteosarcoma cells. These findings suggest that combined administration of ZOL with other anticancer agents may improve the osteosarcoma treatment.