Tatsuya Kinjo

Histological and immunohistochemical observations of mucin-depleted foci (MDF) stained with Alcian blue, in rat colon carcinogenesis induced with 1,2-dimethylhydrazine dihydrochloride

The usefulness of mucin‐depleted foci (MDF), which have recently been proposed as a new preneoplastic biomarker in rat colon carcinogenesis, was histologically investigated in rat colonic tissues treated with 1,2‐dimethylhydrazine dihydrochloride (DMH). The relationship among aberrant crypt foci (ACF), MDF and β‐catenin accumulated crypts (BCAC) was examined by comparing the corresponding computer‐captured images. Twelve male F344 rats were given DMH s.c. at a dose of 40 mg/kg body weight, once a week for 2 weeks, and randomly divided into two groups. Rats in group 1 were given normal drinking water, while those in group 2 were given drinking water containing indomethacin (IND) at 16 ppm for 6 weeks. All animals were sacrificed 8 weeks after the first DMH treatment. The resected colons were fixed in 10% formalin, and stained with Alcian blue for observation of ACF and MDF. Histological and immunohistochemical analysis revealed that the numbers of ACF, MDF and overlapping lesions in group 2 (treated with IND) were significantly decreased, compared with those in group 1. The number of BCAC in group 2 was also significantly lower than that in group 1. The reduction (61.5%) of MDF by IND was much greater than that (29.3%) of ACF. Analyses of the computer‐captured images indicated that MDF had more frequent dysplastic changes and overexpression of β‐catenin than did ACF. MDF having over 4 crypts or MDF with the appearance of ACF corresponded well to BCAC. These results suggest that MDF may be useful as an early biomarker in colon carcinogenesis.

Broadband Dispersion Compensating Octagonal Photonic Crystal Fiber for Optical Communication Applications

We numerically report the design of a modified octagonal photonic crystal fiber (M-OPCF) for broadband dispersion compensation covering the C and L communication bands, i.e., wavelengths ranging from 1530 to 1625 nm. It was shown that the proposed broadband compensating PCF can be designed to simultaneously exhibit a high negative dispersion coefficient and a relative dispersion slope (RDS) close to that of a conventional single-mode optical fiber (SMF). From our results, it was found that the M-OPCF has a large negative dispersion [-226 to -290 ps/(nmkm)] over the C- and L-bands, and an RDS close to that of an SMF of about 0.0034 nm-1. In addition to this, the effective dispersion, residual dispersion, confinement loss, and polarization properties of the proposed PCF are also reported and discussed.

Inhibitory effect of dietary monoglucosylceramide 1-O-β-glucosyl-N-2''' '-hydroxyarachidoyl-4,8- sphingadienine on two different categories of colon preneoplastic lesions induced by 1,2- dimethylhydrazine in F344 rats

Sphingolipids display a wide spectrum of biological activities, including cell growth, differentiation and apoptosis. However, precise mechanisms by which these compounds exert anticancer or cancer‐preventive effects are not known. In the present study, we evaluated the preventive efficacy of enriched dietary monoglucosylceramide 1‐O‐β‐glucosyl‐N‐2′‐hydroxyarachidoyl‐4,8‐sphingadienine (G1CM) on 1,2‐dimethylhydrazine (DMH)‐induced aberrant crypt foci (ACF) and β‐catenin‐accumulated crypt (BCAC) formation in F344 rats during initiation stage. We also examined whether G1CM affects cell proliferation and apoptosis in these lesions. Pure G1CM was isolated from rice bran. Forty‐two rats were divided randomly into five experimental groups. Rats in groups 1–3 were given subcutaneous injections of DMH (40 mg/kg body weight) once a week for 2 weeks. One week before the first injection of DMH, rats in groups 2 and 3 were fed a diet containing 200 and 1000 p.p.m. G1CM, respectively, for 5 weeks. Rats in group 4 were fed a diet containing 1000 p.p.m. G1CM. Rats in group 5 were given the basal diet alone and served as untreated controls. The experiment was terminated 5 weeks after the start. Dietary G1CM at both doses (groups 2 and 3) significantly inhibited the induction of ACF and BCAC (P < 0.001) when compared to group 1 treated with DMH alone. In groups 2 and 3, the proliferating cell nuclear antigen labeling indices of epithelial cells in ACF and BCAC were also lower than in group 1 (P < 0.0001 for ACF, P < 0.05 for BCAC). These results, that dietary G1CM has possible chemopreventive effects in the present short‐term colon carcinogenesis bioassays, suggest that longer exposure may cause suppression of tumor development. (Cancer Sci 2005; 96: 876–881)

Reversibility of cognitive disorder after treatment of dural arteriovenous fistulae.

IntroductionDural arteriovenous fistulae (DAVF) occasionally lead to cognitive disorders whose reversibility after DAVF treatment remains unclear. We studied changes on pre- and post-treatment magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) scans in ten patients with cognitive disorder due to DAVF.MethodsWe studied the symptoms, pre- and post-treatment MRI scans, SPECT findings, and mini-mental state examination (MMSE) and treatment results in ten patients with cognitive disorder due to DAVF. They were divided into two groups; the post-treatment MMSE score exceeded 25 points in group 1 (n = 6) and was lower than 24 points in group 2 (n = 4).ResultsIn the six group 1 patients, pretreatment diffusion-weighted images (DWI) showed hyperintense areas, and SPECT scans demonstrated the preservation of vasoreactivity after acetazolamide challenge. In the four group 2 patients, pretreatment SPECT demonstrated hypoperfusion areas that coincided with the hyperintense areas seen on DWI; there were areas with marked disturbance in vasoreactivity. The post-treatment MMSE score in groups 1 and 2 improved by 13.7 ± 2.4 and 3.8 ± 1.0 points, respectively; the difference was significant at p < 0.01.ConclusionIn patients with cognitive disorder due to DAVF, the preservation of vasoreactivity on SPECT after acetazolamide challenge indicates that their cognitive disorder may be reversible by DAVF treatment.

Design of Highly Nonlinear Birefringent Photonic Crystal Fibers with Ultra-Flattened Chromatic Dispersion

We present a new cladding design for the photonic crystal fibers in order to achieve simultaneously high nonlinearity, dispersion-flattened characteristic, low confinement loss, and polarization maintaining properties. The finite difference method with anisotropic perfectly matched boundary layer is used as the numerical design tool. A nonlinear coefficient of the order 35 W-1 km-1 is obtained with a high birefringence of the order 1.5×10-4 at a 1550 nm wavelength. Ultra-flattened dispersion of 0±0.31 ps nm-1 km-1 is also obtained in a 1440 to 1600 nm wavelength range with low confinement losses less than 0.05 dB/m in the entire dispersion-flat band.

Highly nonlinear photonic crystal fiber with high refractive index core for dental OCT applications

Optical coherence tomography is a technology which supplies the tomographic image using the optical interference. It uses the 1.31 μm wavelength for dental applications. Resolution problems of such a technology can be improved by using supercontinuum light sources as low coherent broadband light is achievable from optical supercontinuum. Photonic crystal fibers have the ability to generate the supercontinuum light even with moderate input power levels. Only thing to consider is to ensure zero or nearly zero dispersion of such fibers at the target 1.31μm wavelength. This paper presents design of a high nonlinear photonic crystal fiber with near-zero dispersion around 1.31μm wavelength based on the finite difference method. Robustness of the design is confirmed numerically by generating wideband supercontinuum.

The possible separation of 12-O-tetradecanoylphorbol-13-acetate-induced skin inflammation and hyperplasia by compound A.

Activated glucocorticoid receptor (GR) acts via two different mechanisms: transcriptional regulation that requires DNA‐binding, and protein–protein interaction between GR and other transcription factors, such as nuclear factor kappa B (NF‐κB) or activator protein 1 (AP‐1). It has been postulated that many important effects of glucocorticoids, including their anti‐inflammatory properties, depend on GRs transrepressive effects on NF‐κB and AP‐1. In the present study, we have employed a TPA‐induced model of skin inflammation and epidermal hyperplasia to determine whether partial activation of the glucocorticoid receptor by compound A (CpdA) is sufficient to reverse the effect of TPA treatment. CpdA is a nonsteroidal GR modulator with high binding affinity, is capable of partial activation of GR. Topical application of TPA twice per week for 2 wk results in inflammation and epidermal hyperplasia. TPA treatment also elevates levels of c‐jun (AP‐1 component), cyclooxygenase‐2 (COX‐2), p50 (NF‐κB component), interleukin‐6 (IL‐6), and tumor necrosis factor (TNF) in the skin. Fluocinolone acetonide (FA) (a full GR agonist) was able to completely reverse the above effects of TPA. When applied alone, CpdA increased the epidermal thickness and keratinocyte proliferation as well as levels of c‐jun, COX‐2, IL‐6, and IFN‐γ. However, CpdA treatment resulted in a decrease in the number of p50 positive cells induced by TPA, suggesting its role in inhibition of NF‐κB. The level of metallothionein‐1 mRNA, regulated by GR was also significantly decreased in skin samples treated with CpdA. Our results suggest that CpdA is able to inhibit GR transactivation and activate only some transrepression properties of GR.

Effects of desipramine on the cell cycle and apoptosis in Ca3/7 mouse skin squamous carcinoma cells

Desipramine (DMI) has been reported to induce glucocorticoid receptor-mediated signal transduction in recent studies. It has been suggested that a non-glucocorticoid receptor signaling pathway might play an important role in skin squamous carcinoma Ca3/7 cells. The aim of this study was to investigate the growth inhibitory effects of DMI on Ca3/7 cells by evaluating the mRNA expression of genes related to apoptosis and cell cycle progression. Hoechst nuclear staining and DNA fragmentation assays were used to detect apoptosis, and the cell cycle was analyzed by flow cytometry. Apoptotic bodies in the nuclei of cells and DNA fragmentation were observed when the Ca3/7 cells were treated with 20 microM DMI for 24 h. Quantitative RT-PCR (reverse transcriptional-polymerase chain reaction) showed that DMI caused a decrease in Bcl-2 and survivin but not Bcl-xL gene expression and an increase in the expression of Bax, Apaf-1, caspase-3 and caspase-7 in a dose- and time-dependent manner. DMI also caused translocation of the apoptosis-inducing factor from the cytoplasm to the nucleus as well as cell cycle arrest in the Ca3/7 cells. Quantitative RT-PCR revealed that DMI decreased the expression of the PCNA gene and caused an increase in the expression of the p21 and p27 genes in the Ca3/7 cells. Our results showed that DMI inhibited the growth of Ca3/7 cells by inducing both apoptosis and cell cycle arrest.

Decagonal Photonic Crystal Fibers with Ultra-Flattened Chromatic Dispersion and Low Confinement Loss

Decagonal PCFs with extremely low dispersion of 0 plusmn 0.26 ps/(nm-.km) in the wavelength range of 1.40 mum to 1.60 mum with confinement loss less than 10-6 dB/km is presented.

Highly nonlinear and polarization maintaining octagonal photonic crystal fiber in 1000nm regions

We propose a highly nonlinear polarization maintaining octagonal photonic crystal fiber possessing flattened dispersion properties within 0.98∼1.26 µm wavelength range. The PCF can be used for broadband supercontinuum generating light source in OCT medical applications.