Biomedical subjects

N Miyoshi

Publications and source records attributed to N Miyoshi.

At least 19 recordsLinked to original sources

PubMed2006

Influence of administration methods on the accumulation of ALA-induced Pp-IX in mouse tongue tumors.

OBJECTIVE: 5-Aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) has been used as a photosensitizer in photodynamic therapy (PDT) for oral cancer. This study investigates the optimal method of administrating ALA by analyzing PpIX fluorescence in tongue tumor tissue. METHODS: Protoporphyrin IX intensities in the mouse (C3H)-transplanted tongue cancer (NR-S1) were compared with those in normal tongue after intraperitoneal (i.p.), oral (p.o.) or topical administration of ALA. Tongues were sampled at various times after ALA administration. PpIX intensities were obtained from frozen sections of each sample by using a spectrophotometer. RESULTS: Protoporphyrin IX intensity in the tumor group peaked at 3 h after the i.p. and 5 h after the p.o. administration of ALA, and these levels were about twice as high as those in the normal group. Maximum PpIX accumulation in the tongue tumor tissue was seen at 5 h after p.o. administration of ALA. In contrast, the topical administration of 20% ALA cream was associated with the lowest PpIX accumulation in the tumor throughout the experiments. CONCLUSION: These results suggested that p.o. administration of ALA was the most effective method in ALA-PDT for oral cancer.

Administration, Oral↗

PubMed2006

The continuing quest to comprehend genomic imprinting.

The discovery of the phenomenon of genomic imprinting in mammals showed that the parental genomes are functionally non-equivalent. Considerable advances have occurred in the field over the past 20 years, which has resulted in the identification and functional analysis of a number of imprinted genes the expression of which is determined by their parental origin. These genes belong to many diverse categories and they have been shown to regulate growth, complex aspects of mammalian physiology and behavior. Many aspects of the mechanism of imprinting have also been elucidated. However, the reasons for the evolution of genomic imprinting remain enigmatic. Further research is needed to determine if there is any relationship between the apparently diverse functions of imprinted genes in mammals, and their role in human diseases. It also remains to be seen what common features exist amongst the diverse imprinting control elements. The mechanisms involved in the erasure and re-establishment of imprints should provide deeper insights into epigenetic mechanisms of wide general interest.

Animals↗

PubMed2006

Renal adenocarcinoma in a ferret.

A spontaneous case of renal tumor was observed in a 7-year-old ovariectomized female pet ferret (Mustela putorius furo). Clinical signs included exhaustion, emaciation, anorexia, and stooping position. At necropsy, a solid and cystic mass replaced the left kidney and adrenal gland. The tumor was composed of pleomorphic epithelial cells with a large number of giant cells. Metastases were recognized in the lung, liver, greater omentum, right renal pelvis, and systemic lymph nodes. Immunohistochemical stains revealed that the tumor cells were positive for CD10, cytokeratin (CAM 5.2), and Ki-67 (MIB-1). On the basis of morphologic and immunohistochemical features, the tumor was diagnosed as a pleomorphic renal adenocarcinoma. This type of neoplasm is very rare in all species and has never been reported in a ferret.

Adenocarcinoma↗

PubMed2005

Increased body fat in mice with a targeted mutation of the paternally expressed imprinted gene Peg3.

Peg3 encodes a C2H2 type zinc finger protein that is implicated in a novel physiological pathway regulating core body temperature, feeding behavior, and obesity in mice. Peg3+/- mutant mice develop an excess of abdominal, subcutaneous, and intra-scapular fat, despite a lifetime of lower food intake than wild-type animals. However, they start life with reduced fat reserves and are slower to enter puberty. These mice maintain a lower core body temperature, fail to respond to a cold challenge, and have lower metabolic activity as measured by oxygen consumption. Plasma leptin levels are significantly higher than in wild types, and Peg3+/- mice appear to have developed leptin resistance. Administration of exogenous leptin resulted in a significant reduction in food intake in wild-type mice that was not observed in Peg3+/- mutants. This mutation, which is strongly expressed in hypothalamic tissue during development, has the capacity to regulate multiple events relating to energy homeostasis.

Adipose Tissue↗

PubMed2004

Extract of vinegar "Kurosu" from unpolished rice inhibits the proliferation of human cancer cells.

The effects of the ethyl acetate extract of "Kurosu" (EK), Japanese traditional vinegar from unpolished rice, on the proliferation of a variety of human cancer cell lines were investigated by using the alamar blue assay. Cancer cell lines included colon adenocarcinoma (Caco-2), lung carcinoma (A549), breast adenocarcinoma (MCF-7), bladder carcinoma (5637), and prostate carcinoma (LNCaP) cells. EK inhibited the proliferation of all tested cell lines in a dose-dependent manner, with inhibition mostly pronounced in Caco-2 cells (up to 62% inhibition at a dose level of 0.025%). Flow cytometry of EK-treated Caco-2 cells showed a decrease in cell number in the G2/M phase and an increase in the sub-G1 phase (apoptotic). In addition, DNA fragmentation was detected in Caco-2 cells cultured with EK by immunostaining. RT-PCR analysis revealed p21 mRNA expression was induced in EK-treated Caco-2 cells. Moreover, PARP cleavage was promoted in EK-treated Caco-2 cells. These results suggest that EK causes G0/G1 arrest through p21 induction and, thus, is a potential apoptosis inducer in Caco-2 cells.

Acetic Acid↗

PubMed2002

Disappearance of M(r) 25,000 protein, a new protein kinase substrate, in parallel with a kind of serpin during embryogenesis.

M(r) 25,000 protein (pp25) is a protein kinase substrate detected recently in Xenopus laevis oocytes [Hashimoto, E. et al. (1995) J. Biochem. 118, 453-460], but the physiological role of this protein remains to be determined. In order to elucidate some characteristics of pp25, a polyclonal antibody was raised against it and the distribution and quantitative changes of this protein were examined using various tissues and biological systems. In Western blot analysis, pp25 was detected only in Xenopus oocytes and not in other frog tissues when the heat-stable cytosolic fraction from each tissue was examined. Although the amount of pp25 apparently did not change during oocyte maturation induced by progesterone, pp25 disappeared in embryos around Nieuwkoop/Faber stages 45-48 in parallel with the change of pNiXa (a kind of serpin). These results suggest that pp25 plays some specific role(s) in Xenopus oocytes and that the level of pp25 changes dramatically during embryonic development.

Animals↗

PubMed2001

Herniation of cervical intervertebral disc: immunohistochemical examination and measurement of nitric oxide production.

STUDY DESIGN: Surgically obtained cervical herniated intervertebral discs were examined histologically and immunohistochemically. The production of nitric oxide (NO) in the local tissue was examined using the electron spin resonance (ESR) method. OBJECTIVES: To investigate the local histologic and immunohistochemical changes in cervical disc herniation, including NO production, and to compare such changes with those in autopsy cases. SUMMARY OF BACKGROUND DATA: Very little is known about the histopathologic processes of cervical disc herniation. In addition, no information is available on the level of in vivo NO production in cervical disc herniation. METHODS: Thirty-six herniated cervical discs obtained from 31 patients were immunohistochemically examined for localization of blood vessels, matrix metalloproteinase (MMP)-3, and inducible NO synthetase (iNOS). We also compared the production of NO, measured by the ESR method, in eight specimens with that of five control discs obtained from fresh cadavers. RESULTS: The presence of herniated discs correlated with the degeneration of cartilaginous endplate and torn anulus fibrosus. Formation of new blood vessels around the herniated discs was detected, using von Willebrand factor antibody, in seven uncontained hernias and 20 contained hernias. Immunohistochemical studies showed the presence of cells positive for MMP-3 (chondrocytes), iNOS (chondrocytes and granulation tissue) in cervical disc hernias. ESR analysis showed a significantly higher NO production in herniated cervical discs than in disc samples of fresh cadavers. CONCLUSIONS: Herniated cervical intervertebral disc is characterized by the presence of an inflammatory process associated with neovascularization and increased expression of MMP-3. Production of NO was markedly high in both contained- and uncontained-type hernias.

Adult↗

PubMed2001

PTEN expression is maintained in sporadic colorectal tumours.

Loss of PTEN (phosphatase and tensin homologue deleted from chromosome 10) function has been implicated in the progression of several types of cancer. Allele loss close to the PTEN locus occurs in sporadic colon cancer and germline PTEN mutations cause Cowden disease, an inherited cancer syndrome characterized by an increased incidence of gastrointestinal tract lesions that can progress to colorectal carcinoma. However, although PTEN is a good candidate for involvement in the pathogenesis of sporadic colon cancer, previous analyses have not revealed a high frequency of somatic mutations in colorectal tumours. Alternative mechanisms which could lead to a loss of PTEN expression in colon cancer have not been investigated. This study monitored PTEN mRNA and protein levels in a panel of 50 tumour tissues obtained from 35 patients with sporadic colon cancer. RT-PCR and immunohistochemistry were used to evaluate the expression of mRNA and protein, respectively, in normal, adenoma and adenocarcinoma colorectal tissues as well as in metastatic lesions. To overcome the problem of heterogeneity and normal stromal cell contamination in homogenized tissue specimens, specific cell types were isolated by microdissection prior to PCR analysis. No loss of PTEN expression was evident in any of the colon tissues examined. PTEN protein was localized exclusively in the cytoplasm of normal and tumour cells and no correlation of immunostaining intensity and tumour stage or grade was revealed. As with previous deletion and mutation analyses, the present study suggests that loss of PTEN expression is not prevalent in sporadic colon cancer.

Adenocarcinoma↗

PubMed2001

Monomerization of photosensitizers by ultrasound irradiation in surfactant micellar solutions.

The absorption and fluorescence properties of pheophorbide-a, Sodium salt of pheophorbide-a and its long chain (C20H39) ester (Pheophytine) were investigated in air-saturated micellar aqueous solutions before and after ultrasound irradiation (48 kHz, 10 min). The absorption spectra changed depending on the surfactant; cetyltrimethyl ammonium bromide (CTAB) or sodium dodecyl sulfate concentrations. The formation of different molecular species in various micellar solutions was estimated from the analysis of the absorption spectra. The absorption bands resulted from an aggregated form of the chromophore present in 50 mM phosphate buffer and in pre-micellar solutions. The specific bands of the aggregate disappeared with a simultaneous increase of the bands of monomer in normal micellar solution. The fluorescence spectra, the lifetimes and the fraction of each component (with a characteristic lifetime) of the chromophore in the micellar solutions changed significantly before and after ultrasound irradiation although the changes in absorption spectra were small. The fluorescence emission band at 710 nm due to the aggregate almost disappeared in the pre-micellar solution after ultrasound irradiation. The fraction of the short-lifetime component estimated for the aggregates decreased 55% in H2O or 85% in 2 mM CTAB, however the long-lifetime components increased after the ultrasound treatment. From these fluorescence properties, it was concluded that the aggregated molecules were converted to a stable monomeric form by ultrasound. Extrapolation of these data to in vivo situations suggests that pretreatment of certain photosensitizers with ultrasound in micellar solutions may lead to increased efficiency of photodynamic therapy since only the monomers are photodynamically active.

Cetrimonium↗

PubMed2001

Apoptosis induction associated with cell cycle dysregulation by rice bran agglutinin.

Effects of rice bran agglutinin (RBA) on human monoblastic leukemia U937 cells were examined in comparison with those of wheat germ agglutinin (WGA) and Viscum album agglutinin (VAA). These lectins inhibit cell growth, and several lines of evidence indicate that the growth inhibition is caused by the induction of apoptosis. We observed that RBA induces chromatin condensation, externalization of membrane phosphatidylserine, and DNA ladder formation, features of apoptosis. DNA ladder formation was inhibited by a general inhibitor against caspases, which are known to play essential roles in apoptosis. Flow cytometric analysis revealed that RBA and WGA cause G2/M phase cell cycle arrest with increased expression of Waf1/p21, while cell cycle arrest was not observed for VAA. These data indicate that RBA induces apoptosis associated with cell cycle arrest in U937 cells, and suggest that the induction mechanism for RBA is similar to that for WGA, but different from that for VAA.

Apoptosis↗

PubMed2001

Teratoma in a feline unilateral cryptorchid testis.

A 14- x 12- x 6-cm (approximately 600 g) cryptorchid testis was surgically removed with the omentum from the posterior portion of the abdominal cavity of a 2-year-old male American Shorthair cat. At the time of a previous orchiectomy, a unilateral testis had been discovered in the scrotum. The cut surface of the cryptorchid testis consisted of solid areas with many cysts containing fluid and spongy soft areas. Histologically, the cryptorchid testis was composed of neuroectodermal components and diffuse immature glial tissues, cystic, tubular, and papillary epithelial tissues, and immature cartilaginous tissues. A metastatic mass in the omentum had histologic structures similar to those of the cryptorchid testis. The present case was diagnosed as teratoma in a feline unilateral cryptorchid testis.

Animals↗

PubMed2001

Subtraction-hybridization method for the identification of imprinted genes.

Imprinted genes show monoallelic expression from either the paternal or maternal genome (1,2), and their regulated expression is usually associated with the existence of parentally differentially methylated regions on genomic DNAs (3,4). Because of this, essentially two different approaches, using either cDNA or genomic DNA as starting material (5) have been developed for systematic isolation of imprinted genes. In this chapter, we describe a subtraction-hybridization method (6-8) as an example of the former approach. Both parthenogenetic embryos and androgenetic embryos (9,10) are the most suitable biological materials for the subtraction or detection of imprinted genes. However, it is difficult to obtain a large amount of such special materials because only a small number of these embryos develop to the d 10 stage (9,10). Thus, polymerase chain reaction (PCR)-based techniques, such as the differential display (11-13) and subtraction-hybridization methods, are necessary to accomplish this experiment. The subtraction-hybridization method has been successfully applied for isolation of both paternally expressed genes (Pegs) (6,14,15) and maternally expressed genes (Megs) (7), and it allows cDNA libraries to be made from a very small amount of biological material. We are convinced that this method can be applied in many fields of biological science.

Animals↗

PubMed2000

Evidence against singlet oxygen formation by sonolysis of aqueous oxygen-saturated solutions of Hematoporphyrin and rose bengal. The mechanism of sonodynamic therapy.

The possible role of singlet oxygen in the mechanism of sonodynamic therapy, the synergistic effect of ultrasound and certain sonosensitizers, was investigated. We used 4,4'-bis(1-p-carboxyphenyl-3- methyl-5-hydroxyl)-pyrazole (DRD 156), a sensitive new reagent which reacts specifically with singlet oxygen (1O2) but not with OH radicals, superoxide anion radicals or H2O2, to produce an EPR detectable signal. Sonolysis (48 kHz) of 90% D2O oxygen-saturated PBS solutions of Hematoporphyrin or Rose Bengal did not lead to the formation of detectable EPR signals of the semiquinone radical of DRD156. In contrast, the EPR signal of the semiquinone radical of DRD156 was observed during photoirradiation of Hematoporphyrin at 505 nm or of Rose Bengal at 544 nm. These results are inconsistent with a major role for singlet oxygen formation in the sonolysis of aqueous solutions of these compounds. An alternative mechanism for sonodynamic therapy involving peroxyl and alkoxyl radicals is discussed.

Electron Spin Resonance Spectroscopy↗

PubMed2000

Identification of an imprinted gene, Meg3/Gtl2 and its human homologue MEG3, first mapped on mouse distal chromosome 12 and human chromosome 14q.

BACKGROUND: The paternal duplication of mouse distal chromosome 12 leads to late embryonal/neonatal lethality and growth promotion, whereas maternal duplication leads to late embryonal lethality and growth retardation. Human paternal or maternal uniparental disomies of chromosome 14q that are syntenic to mouse distal chromosome 12 have also been reported to show some imprinting effects on growth, mental activity and musculoskeletal morphology. For the isolation of imprinted genes in this region, a systematic screen of maternally expressed genes (Megs) was carried out by our subtraction-hybridization method using androgenetic and normally fertilized embryos. RESULTS: We have isolated seven candidate clones of the mouse Meg gene. Among them, we identified a novel maternally expressed imprinted gene, Meg3, on mouse distal chromosome 12 and showed that it was identical to the Gtl2 gene. We also found that the human homologue MEG3 on chromosome 14q was also monoallelically expressed. CONCLUSIONS: This is the first identification of the imprinting gene, both on mouse distal chromosome 12 and on human chromosome 14q, respectively. Because there are no obvious open reading frames in either the mouse Meg3/Gtl2 or human MEG3, the function of these genes remains unclear. However, this result will provide a good basis for the further investigation of several important imprinted genes in this chromosomal region.

Animals↗

PubMed2000

Mouse Peg9/Dlk1 and human PEG9/DLK1 are paternally expressed imprinted genes closely located to the maternally expressed imprinted genes: mouse Meg3/Gtl2 and human MEG3.

BACKGROUND: Genomic imprinting significantly influences development, growth and behaviour in mammals. Systematic screening of imprinted genes has been extensively carried out to identify the genes responsible for imprinted phenotypes and to elucidate the biological significance of this phenomenon. In this study, we applied DNA chip technology for isolating paternally expressed imprinted genes (Pegs). We compared the resulting expression profiles of parthenogenetic and fertilized control embryos to identify novel imprinted genes. RESULTS: A novel paternally expressed mouse imprinted gene, Peg9/Dlk1, was identified. Consistent with this finding, the paternal expression of its human homologue, PEG9/DLK1, was also confirmed. These two genes form imprinted gene clusters with the reciprocally imprinted mouse Meg3/Gtl2 and human MEG3 genes that we first identified on distal chromosome 12 and chromosome 14q32, respectively. CONCLUSIONS: As DNA chip technology allows us to quickly screen a large number of genes, using this technology to search for imprinted genes could accelerate the identification of genes responsible for human and mouse genetic diseases. Dlk1 and DLK1, which encode transmembrane proteins, have six EGF-like repeats and show homology to the Delta gene in Drosophila melanogaster. Because of its homology to mammalian Delta homologues, PEG9/DLK1 may contribute to the scoliosis phenotype observed in maternal uniparental disomy 14 (mUPD14) patients.

Animals↗

PubMed2000

Combination effect of photodynamic and sonodynamic therapy on experimental skin squamous cell carcinoma in C3H/HeN mice.

We studied a combination of photodynamic therapy (PDT) and sonodynamic therapy (SDT) for improving tumoricidal effects in a transplantable mouse squamous cell carcinoma (SCC) model. Two sensitizers were utilized: the pheophorbide-a derivative PH-1126, which is a newly developed photosensitizer, and the gallium porphyrin analogue ATX-70, a commonly used sonosensitizer. Mice were injected with either PH-1126 or ATX-70 i.p. at doses of 5 or 10 mg/kg.bw. At 24 (ATX-70) or 36 hr (PH-1126) (time of optimum drug concentration in the tumor) after injection, SCCs underwent laser light irradiation (88 J/cm2 of 575 nm for ATX-70; 44J/cm2 of 650 nm for PH-1126) (PDT), ultrasound irradiation (0.51 W/cm2 at 1.0 MHz for 10 minutes) (SDT), or a combination of the two treatments. The combination of PDT and SDT using either PH-1126 or ATX-70 as a sensitizer resulted in significantly improved inhibition of tumor growth (92-98%) (additive effect) as compared to either single treatment (27-77%). The combination using PH-1126 resulted in 25% of the treated mice being tumor free at 20 days after treatment. Moreover, the median survival period (from irradiation to death) of PDT + SDT-treated mice (> 120 days) was significantly greater than that in single treatment groups (77-95 days). Histological changes revealed that combination therapy could induce tumor necrosis 2-3 times as deep as in either of the single modalities. The combination of PDT and SDT could be very useful for treatment of non-superficial or nodular tumors.

Animals↗

PubMed1999

Cataract formation through the polyol pathway is associated with free radical production.

The relationship between sugar cataract formation and radical production was investigated. The in vivo formation of free radicals in the lenses of rats fed on a diet containing 25% and 50% galactose was studied using the electron spin resonance (ESR) spin trapping method. Effects of treatment with aldose reductase inhibitor (ARI) SNK-860 on free radical formation were determined in 25% and 50% galactose fed rats. Hydroxyl radical (*OH) adduct of the spin trap 5,5'-dimethyl-1-pyrroline- N -oxide (DMPO) was directly detected in the superficial cortical cataract obtained from 25% and 50% galactose-fed rats. *OH production was completely inhibited by ARI SNK-860 in both galactose groups. Polyol accumulated in rat lenses given 50% galactose with a peak within the first 2 weeks, and was significantly inhibited by SNK-860. The increase in *OH production was considered with the polyol accumulation in both galactose groups. The dose of SNK-860 to inhibit *OH by 50% level was estimated at 3 m by the method of kinetic competition in vitro experiment. SNK-860 is not an effective *OH scavenger compared to other *OH scavengers. The results of the present study suggest that *OH is indirectly inhibited by SNK-860 resulting from decreasing polyol and *OH formation is related to sugar cataract formation in early stages, possibly via the Fenton reaction involving H2O2 produced from the activated polyol pathway. We suppose that *OH may accelerate damage to the cell membrane of lens fibers resulting from polyol accumulation *OH may play an important role in the early stage of sugar cataract process.

Aldehyde Reductase↗

PubMed1999

Effects of cysteamine and cystamine on the sonochemical accumulation of hydrogen peroxide--implications for their mechanisms of action in ultrasound-exposed cells.

Based on the observed cytoprotective effect of the intracellularly permeable radical scavenger cysteamine (+NH3CH2CH2SH) in cells exposed to ultrasound and the lack of protection by its oxidized cell-nonpermeable form, cystamine (+NH3CH2CH2S-SCH2CH2NH3+), it was suggested that inertial cavitation (the growth of small gas bubbles present in the liquid exposed to ultrasound and their subsequent violent collapse) and associated free radical production may occur intracellularly (Radiat. Res. 89:369; 1982). Here we demonstrate that high concentrations (> 10 mM) of the thiol cysteamine effectively lower H2O2 yields following ultrasound exposure in argon- and air-saturated phosphate buffered saline (PBS), while cystamine is less effective under argon and practically without effect in air-saturated PBS. Direct removal of H2O2 by cysteamine is the dominant mechanism while scavenging of the H2O2 precursors .OH and superoxide plays a lesser role. Since H2O2 is a known cytotoxic species capable of penetrating cells if produced extracellularly, these results offer an alternative hypothesis for the protective effect of cysteamine and the lack of protection by cystamine, based on their differential ability to lower ultrasound-dependent H2O2 yields, without the necessity of invoking intracellular cavitation.

Argon↗