Biomedical subjects

Mitsuharu Matsumoto

Publications and source records attributed to Mitsuharu Matsumoto.

At least 19 recordsLinked to original sources

PubMed2006

Vitamin B6 suppresses apoptosis of NM-1 bovine endothelial cells induced by homocysteine and copper.

Hyperhomocysteinemia is an important risk factor for atherosclerosis. We previously reported that formation of early atherosclerosis in the rat aorta was associated with hyperhomocysteinemia and reduction of antioxidant activity caused by low concentration of vitamin B(6)in vivo. In the present study, we examined effects of vitamin B(6) on apoptosis of bovine endothelial cells (NM-1 cells) treated with homocysteine and copper. Homocysteine and copper induced extracellular hydrogen peroxide, intracellular ROS and cellular lipid peroxide levels. Cell viability was reduced to 30% compared to that of control cells. On the other hand, pyridoxal treatment as well as EDTA treatment increased viability of NM-1 cells treated with homocysteine and copper to about 60%, and significantly decreased extracellular hydrogen peroxide, intracellular ROS and cellular lipid peroxide levels. The treatment of catalase recovered cell viability and reduced the level of extracellular hydrogen peroxide and intracellular ROS. Cell death by homocysteine and copper was confirmed to be due to apoptosis by evaluation of DNA fragmentation and by TUNEL assay. However, apoptosis of NM-1 cells induced by homocysteine and copper was due to a caspase-independent pathway as it was not inhibited by the caspase inhibitor, Z-VAD-fmk. Apoptosis of NM-1 cells induced by homocysteine and copper accompanied with mitochondrial permeability but not cytochrome c release. These results suggest that pyridoxal treatment suppresses apoptosis of NM-1 cells induced by homocysteine and copper, most likely through antioxidant effects.

Animals↗

PubMed2006

Perchloric acid-soluble protein is expressed in enterocytes and goblet cells in the intestine and upregulated by dietary lipid.

We previously identified perchloric acid-soluble protein (PSP) in the rat liver, kidney, brain and lung, and reported that it appeared to be related to repression of cell proliferation. In the present study, we clarified that PSP was expressed in the intestine, and found that the amino acid sequence of the intestinal PSP was consistent with those of other PSPs present in other tissues. An immunohistochemical study revealed that PSP was expressed in enterocytes and goblet cells, but not in other cell types among the lamina propria epithelial cells. A comparison of the expressions of PSP and proliferating cell nuclear antigen demonstrated that the proliferating cells did not express PSP. Intestinal PSP expression was induced by approximately 3-fold by oral administration of dietary fat. These findings indicate that the proliferation repression activity may be related to renewal of the intestinal epithelium, and that PSP is one of the fatty acid-inducible proteins.

Animal Feed↗

PubMed2006

Immunohistochemical localization of ghrelin in rodent kidneys.

Ghrelin is a novel peptide hormone, originally identified in the rat and human stomach that plays various important roles. In the present study, we report the intra-renal localization of ghrelin in laboratory rodents. Kidneys from 3 month-old mice, rats and hamsters of both sexes were analyzed by immunohistochemistry. Positive signals were clearly observed in the epithelium of the distal tubules, whereas other segments of the nephron or interstitial cells, including juxtaglomerular cells, showed negative reactions. Pre-embedding immunoelectron microscopy revealed positive signals exclusively on the basolateral membrane in the distal tubular cells and in the collecting ducts. In addition, prepro-ghrelin gene expression was assessed by RT-PCR, and the expected 329-bp prepro-ghrelin mRNA was clearly detected in the kidney. On Western blot analysis, although a specific band for ghrelin (3 kDa) was not detected in the kidney, the expected band for prepro-ghrelin (13 kDa) was clearly detected in both the stomach and the kidney. This paper clarified the intra-renal localization of ghrelin.

Animals↗

PubMed2006

Bacteroides intestinalis sp. nov., isolated from human faeces.

During studies of the microbiota of human faeces, five strains of Gram-negative anaerobic rods were isolated following growth in a polyamine-deficient medium. These strains belonged to the genus Bacteroides on the basis of 16S rRNA gene sequence data. 16S rRNA gene sequence similarity between one of the strains, 341T, and recognized species within the genus Bacteroides was <95 %. The DNA G+C content (44 mol%) and major fatty acid composition (anteiso-C(15 : 0), 32.0 %) supported the affiliation of strain 341(T) to the genus Bacteroides. Biochemical tests and DNA-DNA hybridization analysis demonstrated that strain 341T was distinct from Bacteroides uniformis and Bacteroides helcogenes, to which it was related most closely. On the basis of these data, a novel Bacteroides species, Bacteroides intestinalis sp. nov., is proposed with strain 341T (= JCM 13265T = DSM 17393T) as the type strain.

Bacteroides↗

PubMed2006

Bacteroides finegoldii sp. nov., isolated from human faeces.

Two strains, 199T and 176, of Gram-negative, anaerobic, rod-shaped, non-spore-forming bacteria were isolated during studies of microbiota in human faeces using polyamine-deficient medium. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolated strains belonged to the genus Bacteroides. The G+C content (42.4-43.0 mol%) and major fatty acid composition (anteiso-C15:0, 31.8-36.2 %) supported the affiliation of the two strains to the genus Bacteroides. 16S rRNA gene sequence similarities with their closest neighbours, Bacteroides thetaiotaomicron and Bacteroides ovatus, ranged from 94.6 to 96.5 %. DNA-DNA hybridization and phenotypic analysis showed that the two strains belonged to the same species (DNA-DNA relatedness of 89 %) and were distinct from their close relatives, B. thetaiotaomicron and B. ovatus (<23 % DNA-DNA relatedness). On the basis of these data, a novel species of the genus Bacteroides, Bacteroides finegoldii sp. nov., is proposed, comprising the designated type strain 199T (=JCM 13345T=DSM 17565T) and strain 176 (=JCM 13346).

Adult↗

PubMed2006

Bacteroides dorei sp. nov., isolated from human faeces.

Two Gram-negative, anaerobic, non-spore-forming rod-shaped organisms were isolated from human faeces. These isolates were tentatively identified as Bacteroides based on morphological and biochemical criteria and appeared closely related to Bacteroides vulgatus ATCC 8482(T). The 16S rRNA gene sequence analysis showed that the isolates were highly related to each other (99.5 %) and confirmed their placement in the genus Bacteroides. 16S rRNA gene sequence similarity values with close phylogenetic neighbours Bacteroides vulgatus ATCC 8482(T) (96 %) and Bacteroides massiliensis CCUG 48901(T) (93 %) preliminarily demonstrated that the organisms represented a novel species. The results of phenotypic, chemotaxonomic and 16S rRNA gene sequence analyses, and DNA-DNA homology values provided evidence that these two unknown isolates represent a single species and should be assigned to a novel species of the genus Bacteroides, as Bacteroides dorei sp. nov. The type strain is JCM 13471(T) (=DSM 17855(T)).

Anaerobiosis↗

PubMed2006

A miniaturized adaptive microphone array under directional constraint utilizing aggregated microphones.

This paper introduces a miniaturized microphone array using the Directionally Constrained Minimization of Power (DCMP) method, which utilizes the transfer functions of microphones located at the same place, namely aggregated microphones. The phased microphone array realizes a noise reduction and direction of arrival (DOA) estimation system according to differences in the arrival time, phase shift, and/or the level of the sound wave for each microphone. Hence it is difficult to miniaturize the microphone array. The objective of our research is to miniaturize the system size using aggregated microphones. In this paper, we first show that the phased microphone array system and the proposed aggregated microphone system can be described within the same framework. We then apply a microphone array under directional constraint to the aggregated microphones and compare the proposed method with the microphone array. We show the directional pattern of the aggregated microphones. We also show the experimental results regarding DOA estimation.

Journal Article↗

PubMed2006

Immunoprotection of recombinant leptospiral immunoglobulin-like protein A against Leptospira interrogans serovar Pomona infection.

We previously reported the cloning and characterization of leptospiral immunoglobulin-like proteins LigA and LigB of Leptospira interrogans. LigA and LigB are conserved at the amino-terminal region but are variable at the carboxyl-terminal region. Here, we evaluate the potential of recombinant LigA (rLigA) as a vaccine candidate against infection by L. interrogans serovar Pomona in a hamster model. rLigA was truncated into conserved (rLigAcon) and variable (rLigAvar) regions and expressed in Escherichia coli as a fusion protein with glutathione-S-transferase (rLigA). Golden Syrian hamsters were immunized at 3 and 6 weeks of age with rLigA (rLigAcon and rLigAvar) with aluminum hydroxide as an adjuvant. Hamsters given recombinant glutathione-S-transferase (rGST)-adjuvant and phosphate-buffered saline-adjuvant served as nonvaccinated controls. Three weeks after the last vaccination, all animals were challenged intraperitoneally with 10(8) L. interrogans serovar Pomona bacteria (NVSL 1427-35-093002). All hamsters immunized with recombinant LigA survived after challenge and had no significant histopathological changes. In contrast, nonimmunized and rGST-immunized hamsters were subjected to lethal doses, and the hamsters that survived showed severe tubulointerstitial nephritis. All vaccinated animals showed a rise in antibody titers against rLigA. Results from this study indicate that rLigA is a potential vaccine candidate against L. interrogans serovar Pomona infection.

Adjuvants, Immunologic↗

PubMed2006

Anti-inflammatory metabolite production in the gut from the consumption of probiotic yogurt containing Bifidobacterium animalis subsp. lactis LKM512.

There is little evidence for a relationship between probiotic metabolites and host cytokine production. We investigated in the present study the possibility that anti-inflammatory metabolites can be produced in the gut by LKM512 yogurt consumption by using murine macrophage-like J774.1 cells and extracts prepared from the feces of elderly volunteers. These volunteers' acute inflammation had been inhibited by LKM512 yogurt consumption in a previous test. The tumor necrosis factor (TNF)-alpha production elicited in J774.1 cells stimulated by lipopolysaccharide (LPS) and in the fecal extracts obtained during the period of LKM512 yogurt consumption was significantly decreased (p<0.05) than the pre-consumption baseline level. These findings and previous data enable us to conclude that intestinal bacterial metabolites produced by LKM512 yogurt consumption contributed to suppressing the inflammatory cytokine produced by macrophages and that one of the anti-inflammatory metabolites in the fecal extracts was likely to have been a polyamine.

Aged↗

PubMed2006

Vitamin B6 suppresses growth of the feline mammary tumor cell line FRM.

Growth of FRM cells was inhibited by the addition of pyridoxine in a dose-dependent manner. Use of 5 mM pyridoxine caused an almost complete arrest of cell growth. Pyridoxal was as effective as pyridoxine, but pyridoxamine showed weak inhibitory action. Electron-microscopic examination of control cells revealed large nuclei and cellular membranes with villi, but, in pyridoxine-treated cells, condensed or degraded nuclei were observed. Many vacuoles and cholesterol crystals were widely distributed inside the cellular membrane of pyridoxine-treated cells. One of the vacuoles was identified as a lipid droplet. The DNA ladder was observed in the pyridoxine-treated cells. It is suggested that pyridoxine treatment of FRM cells causes cytolysis of cells by apoptosis.

Animals↗

PubMed2006

Strain differences in morphometrical characteristics of rat kidneys.

To clarify the strain differences in the morphology of the rat kidneys, we investigated the morphometrical characteristics of the kidneys of Slc:Wistar, Slc:SD, and F344/NSlc rats. The diameter of the renal corpuscles in female F344/N rats is smaller than that in female Wistar rats. Although sex differences (males>females) were shown in SD and F344/N rats, no effects of castration were detected in any of the groups. Strain-dependent differences in the percentage of renal corpuscles with a cuboidal parietal layer were found in both male and female groups. The highest percentage of them was noted in male Wistar rats. Effects of castration were observed in female Wistar and male F344/N rats, and the values after castration were significantly higher than those in the intact animals. As for the number of proximal convoluted tubular nuclei, no strain differences were detected in either the male or female groups. Although a sex difference was found in SD rats (female>male), no effects of castration were detected in any of the groups. In female F344/N rats, numerous numbers of PAS-positive granules, which were observed in the proximal convoluted and straight tubular epithelia, were noted. Orchiectomy induced an increase of these granules in male SD and F344/N rats, but ovariectomy showed no effects on them in any strains. This is the first study to clarify the strain differences in the morphological characteristics of the kidneys in ordinary rat strains.

Animals↗

PubMed2006

Rodent renal structure differs among species.

In the present study, we histologically and morphometrically investigated species differences in renal structure using laboratory rodents (mice, gerbils, hamsters, rats, and guinea pigs). Morphometric parameters were as follows, 1) diameter of the cortical renal corpuscles, 2) diameter of the juxtamedullary renal corpuscles, 3) percentage of the renal corpuscles with a cuboidal parietal layer, 4) number of nuclei in proximal convoluted tubules (PCTs) per unit area of cortex, 5) semi-quantitative score of the periodic acid-Schiff (PAS) -positive granules in PCTs, and 6) semi-quantitative score of the PAS-positive granules in proximal straight tubules (PSTs). Significant species differences were detected for each parameter, and particularly severe differences were observed in the PAS-positive granules of PCTs and PSTs. Granular scores varied among species and sexes. Vacuolar structures that did not stain with PAS or hematoxylin-eosin were observed in the renal proximal tubules. The appearance and localization of these vacuolar structures differed remarkably between species and sexes.

Animals↗

PubMed2006

Neuronal nitric oxide synthase and cyclooxygenase-2 in diabetic nephropathy of type 2 diabetic OLETF rats.

Neuronal nitric oxide synthase (nNOS) and cyclooxygenase-2 (COX-2) regulate the tubuloglomerular feedback (TGF) and renin-angiotensin system (RAS) in the kidney. In type 1 diabetic rats, renal overproduction of these enzymes and their relationship to the pathogenesis of diabetic nephropathy has been demonstrated. In the present study, we histologically and immunohistochemically investigated the kidneys of Otsuka Long-Evans Tokushima Fatty (OLETF) rats, as a model of type 2 diabetes, at 62 weeks of age (chronic phase of diabetes). The kidneys of OLETF rats showed typical diabetic nephropathy. Quantitative scores for glomerulosclerosis and interstitial fibrosis in OLETF rats were significantly higher than those of age-matched control Long-Evans Tokushima Otsuka (LETO) rats. nNOS- and COX-2-positive immunoreactions were observed in the distal tubules and collecting ducts. These reactions appeared to be more widely distributed in OLETF, and the number of nNOS-and COX-2-positive sites in the OLETF were significantly more than those in LETO rats. Expression of renin, angiotensin II, and inducible nitric oxide synthase (iNOS) were also examined immunohistochemically, and no differences between OLETF and LETO rats were observed in the distributions and the number of immunoreactive-sites. In conclusion, the overproduction of nNOS and COX-2 in the kidney of OLETF rats was confirmed, suggesting that the overproduction of nNOS and/or COX-2 does not affect the intrarenal RAS or iNOS production but does affect TGF.

Angiotensin II↗

PubMed2006

Morphometric study of gender differences with regard to age-related changes in the C57BL/6 mouse kidney.

To investigate gender differences with regard to age-related changes in the mouse kidney, kidneys from male and female C57BL/6Cr mice were morphometrically examined at 2, 4, 12, 27 and 33 months of age. Gender differences were clearly observed in age-related changes in renal corpuscle diameter, in addition to semiquantitative scores of glomerular damage and interstitial fibrosis. A greater relative increase in renal corpuscle diameter was observed in females compared to males, and scores indicating glomerular damage and interstitial fibrosis were more severe in males than in females.

Aging↗

PubMed2006

Species specific differences in the ratio of short to long loop nephrons in the kidneys of laboratory rodents.

The ratio of short to long loop nephrons (SLNs and LLNs, respectively) in laboratory rodents (mice, rats, hamsters, gerbils, and guinea pigs) was investigated using the air cast method. In mice and rats, the percentage of SLNs was significantly higher than that of LLNs, while in hamsters and gerbils, the reverse was true (% of LLNs >% of SLNs). In guinea pigs, no significant difference in the percentages of LLNs and SLNs was noted.

Animals↗

PubMed2005

Nuclear transfer of perchloric acid-soluble protein by endoplasmic reticulum stressors.

Perchloric acid-soluble protein (PSP) is highly conserved during evolution from bacteria to mammals. Although PSP has been recognized as an inhibitor of translation and proliferation in vitro, its precise biological role has not yet been elucidated. Since we previously found similar distributions for PSP and the endoplasmic reticulum (ER) and Golgi complex, the intracellular distribution of PSP was analyzed in more detail. Immunofluorescence studies indicated that PSP co-localized with the ER and Golgi complex, since the distribution pattern of PSP was well matched to both of these organelles. An immunoelectron microscopic study revealed PSP was located not only in the cytosol but also on the surface of the outer ER membrane. Since PSP was present on the ER, we speculated that it may be associated with ER function. Therefore, we analyzed whether or not the ER stress response, which is one of the ER functions, affected PSP expression. The results showed that various ER stressors (thapsigargin, A23187, tunicamycin, brefeldin A, and cisplatin) provoked a dramatic change in the localization of PSP from outside of the nucleus to inside the nucleus within 3 h. Moreover, the ER stressors induced PSP expression. These results suggest that PSP is involved in the cellular response to ER stressors, and that the change in localization of PSP from the ER to the nucleus may be associated with ER stress responses.

Active Transport, Cell Nucleus↗

PubMed2005

Perchloric acid-soluble protein regulates cell proliferation and differentiation in the spinal cord of chick embryos.

The role of perchloric acid-soluble protein (PSP) was investigated in chick embryos. Fluorescently labeled anti-chick liver (CL)-PSP IgG was injected into the yolk sac in ovo at embryonic day 3, and became localized in neuroepithelial cells. Within 12 h, morphological changes were observed in 37.5% of anti-CL-PSP IgG-injected embryos, and the neuroepithelial cells formed a wavy line. No significant changes were observed in embryos injected with non-immune IgG or PBS. Increased expression of PCNA and decreased expression of neuronal class III beta-tubulin were observed in the spinal cord after anti-CL-PSP IgG injection. These results suggest that PSP controls the proliferation and differentiation of neuroepithelial cells in chick embryos.

Animals↗

PubMed2005

Thermostabilized ovalbumin that occurs naturally during development accumulates in embryonic tissues.

We have reported that ovalbumin accumulates without digestion in various tissues during embryonic development of the chicken. There are different types of ovalbumin with respect to thermal stability and one of them, which was named "HS-ovalbumin" in the present study, was found to have a T(m) value of 83 degrees C and to be present dominantly in albumen, egg yolk, amniotic fluid, and serum of fertilized eggs. HS-ovalbumin, arising physiologically from its native form (N-ovalbumin), is reminiscent of the previously described intermediate form appearing during the production processes of the so-called S-ovalbumin, which disappeared shortly in fertilized eggs. We showed that HS-ovalbumin is distinguishable from S-ovalbumin by a monoclonal antibody and also from N-ovalbumin by the stability to heating. At the late stages of development, ovalbumin of amniotic fluid seems to be swallowed through pharynx, carried in the intestine through stomach, and absorbed in the blood. Analyses by monoclonal antibody and heat treatment indicated that the HS-form occupies the largest fraction of ovalbumin that accumulates in the embryonic tissues. The current findings suggest that HS-ovalbumin is crucial for embryogenesis.

Animals↗