Biomedical subjects

S Kobayashi

Publications and source records attributed to S Kobayashi.

At least 55 records · Page 3Linked to original sources

PubMed2005

Retroperitoneal lymphocele associated with lumbar spine fracture: report of an unusual case.

DESIGN: To describe a case of retroperitoneal lymphocele as an extremely rare complication after lumbar spine fracture. OBJECTIVE: To discuss the possible mechanism of development of retroperitoneal lymphocele following blunt trauma to the ureter and lumbar spine. SETTING: Fukui University Hospital, Fukui, Japan. RESULTS: A 71-year-old man presented with severe intractable low back pain caused by a huge retroperitoneal lymphocele, which was considered to be related to an occult L4 vertebral fracture and a blunt ureteral injury. The retroperitoneal lymphocele also caused significant instability at L3-4 level, thus requiring surgical resection followed by interbody fusion. CONCLUSION: Physicians should be aware that such unusual retroperitoneal lymphocele might develop even after a blunt ureteral injury or a minor lumbar spine fracture.

Aged↗

PubMed2005

Human herpesvirus-6 encephalitis after unrelated cord blood transplantation.

Here we describe 2 patients with acute leukemia in whom human herpesvirus-6 (HHV-6) encephalitis developed after cord blood transplantation. In patients 1 and 2, generalized seizure and coma developed on day 62 and day 15, respectively, after cord blood transplantation, which failed to engraft in patient 1. Magnetic resonance imaging (MRI) of patient 1's brain showed low-intensity signals at the gyri of the bilateral lateral lobes on T1-weighted images and high-intensity signals on T2-weighted images. MRI of patient 2's brain showed high-intensity signals in bilateral white matter on T2-weighted images and on fluid-attenuated inversion recovery (FLAIR) images. Cerebrospinal fluid examination revealed an increased protein level with pleocytosis in patient 1 and a normal protein level without pleocytosis in patient 2. Polymerase chain reaction analysis detected HHV-6 DNA in the cerebrospinal fluid of both patients. Patient 1 recovered after administration of gancyclovir for 3 weeks. However, she again suffered from encephalitis after discontinuation of gancyclovir, and died of sepsis. Patient 2 died from an anoxic brain caused by generalized seizure. When neurological symptoms and signs appear in hematopoietic stem cell transplantation recipients, we should consider HHV-6 encephalitis and promptly and empirically treat them with gancyclovir or foscarnet.

Adult↗

PubMed2005

Function of sigma1 receptors in Parkinson's disease.

OBJECTIVE: The objective of this study was to investigate the mapping of sigma1 receptors in Parkinson's disease (PD) using [11C]SA4503 and positron emission tomography (PET), and to assess whether sigma1 receptors are involved in the damaged dopaminergic system in PD patients. MATERIALS AND METHODS: We studied seven normal volunteers and six PD patients. The low density of dopamine transporters and the normal or high density of dopamine receptors were confirmed in the putamen of all patients using [11C]CFT and [11C]RAC PET. A dynamic series of PET data acquisition was performed with arterial blood sampling. We computed the binding potential (BP) of [11C]SA4503. RESULTS: In PD patients, the BP was significantly lower on the more affected than the less affected side of the anterior putamen, although there was no significant difference with respect to the BP between patients and controls. CONCLUSIONS: Release of dopamine is reduced asymmetrically in the putamen of early PD. [11C]SA4503 PET is an indicator of presynaptic dopaminergic damage in PD.

Adult↗

PubMed2005

Electrophoretically separation of the synovial fluid proteins in rabbit temporomandibular arthritis induced by mechanical loading.

BACKGROUND: The concentration of protein in synovial fluid (SF) of temporomandibular joints (TMJs) with disorders tends to be increased. We investigated the protein composition of SF of rabbits in which arthritis of the TMJ was induced. METHOD: Arthritis was induced in six TMJs in six rabbits by exertion of a load for 4 weeks. Six non-loaded TMJs in six rabbits served as controls. The protein concentration and content in TMJ SF of the two groups were compared. RESULTS: The mean protein concentration was higher in the SF of the loaded group than in that of the non-loaded group (1824 microg/ml vs. 398 microg/ml, P = 0.002). Proteins with molecular weights of more than 95 kDa were abundant in the loaded group (P < 0.05). CONCLUSION: Temporomandibular arthritis induced by mechanical loading in rabbit is accompanied by an increase in the abundance of relatively high molecular weight proteins in SF.

Animals↗

PubMed2005

Increased circulating endothelial progenitor cells in patients with bacterial pneumonia: evidence that bone marrow derived cells contribute to lung repair.

BACKGROUND: Tissue repair often occurs in organs damaged by various inflammatory diseases including pneumonia. Inflammatory stimuli induce a rapid and massive release of inflammatory cells from the bone marrow. Recent studies have suggested that bone marrow cells have the potential to differentiate into a variety of cell types. It has been shown that administration of lipopolysaccharide (LPS) to murine lungs induces a rapid release of endothelial progenitor cells (EPCs) into the circulation, and that bone marrow derived progenitor cells including EPCs contribute to lung repair after lung injury in mice. This study was undertaken to investigate the mobilisation of EPCs in humans following acute pneumonia. METHODS: Peripheral blood mononuclear cells (PBMCs) were isolated from venous blood taken from 23 patients with pneumonia during both the acute and convalescent phase. 1x10(6) PBMCs were plated on fibronectin coated culture slides and cultured in culture medium for endothelium. The numbers of EPCs were counted 8 days after plating. RESULTS: The number of circulating EPCs significantly increased in patients with pneumonia (p<0.0001). Patients with low EPC counts tended to have persistent fibrotic changes in their lungs even after their recovery from pneumonia. CONCLUSIONS: Inflammatory stimuli induce a rapid release of EPCs into the circulation in humans. A sufficient number of EPCs is necessary for proper lung repair following bacterial pneumonia.

Aged↗

PubMed2005

Pleiotropic effects of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors: candidate mechanisms for anti-lipid deposition in blood vessels.

The 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) are considered first-line therapeutic agents for the prevention of coronary heart disease and atherosclerotic disorders related to hypercholesterolemia. Statins inhibit lipid deposition in the aortic endothelium. Although it has been accepted that the statins are potent inhibitors of cholesterol biosynthesis in the liver and that they lower circulating cholesterol levels, several cholesterol-independent (pleiotropic) effects have been reported. The cholesterol-independent effects of statins involve normalization of the nitric oxide (NO)-NO synthase system, anti-inflammatory effects through the inhibition of cytokine/chemokine production, inhibition of vascular smooth muscle cell proliferation and migration, and inhibition of platelet thrombus formation/reduction of the thrombotic response. Some pleiotropic effects of statins may depend on the inhibition of the biosynthesis of farnesyl- and geranylgeranyl-nonsterol compounds from mevalonate in the cells. The Rho/Rho kinase pathway and the phospatidylinositol-3 kinase/Akt pathway mediate the pleiotropic effects of statins. As variations occur in absorption, metabolism, and excretion mechanisms due to the characteristics of specific statins including their hydrophilicity and lipophilicity, there are differences in the transfer mechanisms of statins into tissues. However, the pleiotropic effects occur regardless of statin hydrophilicity and lipophilicity. This review summarizes the pleiotropic effects of statins on lipid deposition in blood vessels.

Animals↗

PubMed2005

Growth, reproduction, and lactation in somatic cell cloned cows with short telomeres.

We previously showed that telomere lengths of 10 somatic cell cloned cows were significantly shorter than normal. In this study, we investigated growth, reproduction, and lactation in these animals to determine if shortened telomeres have any effect on these characteristics. Six Holstein and 4 Jersey cloned cows, derived from oviduct cells, were reared under general group feeding. Body weights were recorded from birth to 48 mo of age. A number of reproductive characteristics were screened during the prepubertal, postpubertal, and postpartum periods. After parturition, milk yields were recorded daily and percentages of milk fat, proteins, and solids-not-fat were measured at monthly intervals. These data were used to estimate production of milk components over a 305-d period. Overall, the cloned heifers exceeded standard growth rates for each breed. The cows were inseminated at the first estrus after they reached 450 d of age, and delivered normal calves except for one stillbirth in the Holstein group. They were inseminated at postpartum estrus to provide second and third parturitions and, again, these pregnancies were normal. Gestational periods and birth weights of the calves were both within the normal range. The average total milk yield per cow in Holstein group clones was less than that of the original cow, whereas Jersey group clones showed a higher average milk yield than the original cow. In both groups of cloned cows, inter-individual variation in milk production was relatively large; however, the coefficient of variation was less than 10%. Our results suggest that the cloned cows have normal growth, reproductive, and lactation characteristics, and thus normal productivity, despite having reduced telomere lengths.

Animals↗

PubMed2005

Supplement nephropathy due to long-term, high-dose ingestion of ascorbic acid, calcium lactate, vitamin D and laxatives.

A 48-year-old Japanese woman previously in good health was found to have severe proximal tubular dysfunction with a high serum level of ascorbic acid (57.3 microg/ml, reference range: 1.9 - 15.0 microg/ml). Renal biopsy specimen showed marked tubulointerstitial damage, i.e. tubular atrophy, dilatation of tubular lumen with flattened tubular epithelial cells, vacuolization of proximal and distal tubular epithelial cells, and severe interstitial fibrosis with mild infiltration of mononuclear cells. Calcified lesions, which caused tubular obstruction or stenosis, were also seen in interstitial area adjacent to degenerated proximal tubuli. Hypokalemic nephropathy, probably due to long-term use of laxatives, was clearly shown. However, calcified lesions seemed to be caused by inappropriate excessive daily ingestion of ascorbic acid (6 000 mg/day), calcium lactate, and vitamin D because of the patient's misunderstanding that these supplements could keep her in a good health. This condition may be clinically called "supplement nephropathy".

Ascorbic Acid↗

PubMed2005

IFN-alpha enhances TNF-alpha-induced apoptosis through down-regulation of c-Myc protein expression in HL-60 cells.

We examined the effect of interferon-alpha (IFN-alpha) in combination with tumor necrosis factor-a (TNF-alpha) on growth, differentiation and apoptosis in HL-60 human myeloid leukemia cells. IFN-alpha inhibited cell growth and induced apoptosis, but not differentiation, in HL-60 cells. IFN-alpha enhanced TNF-alpha-induced apoptosis. We also investigated the expression of c-Myc and Bcl-2 oncoproteins, which are implicated in the survival or death of a cell. The levels of c-Myc protein expression were not changed by IFN-alpha alone at 24hrs of treatment, but were down-regulated at 72 hrs, accompanied by the appearance of apoptotic cells. While, IFN-alpha did not affect the level of Bcl-2 protein expression during this cultivation time. Interestingly, a combination treatment of IFN-alpha with TNF-alpha showed a greater decrease of c-Myc expression than TNF-a alone at 24hrs. Whereas, IFN-alpha did not significantly modulate Bcl-2 expression levels which were down-regulated by TNF-alpha. Therefore, the enhancement of TNF-alpha-induced apoptosis by IFN-a might be closely associated with the greater down-regulation of c-Myc protein, rather than Bcl-2. In contrast, with rapid down-regulation of c-Myc expression caused by TNF-alpha, IFN-alpha down-regulated c-Myc rather late (at 72 hrs), suggesting that both cytokines have a distinct pathway regulating c-Myc protein expression. However, the enhancement of apoptosis in the combination treatment would suggest the presence of a common signaling pathway for induction of apoptosis at down-stream of c-Myc.

Apoptosis↗

PubMed2004

PARK6-linked autosomal recessive early-onset parkinsonism in Asian populations.

The authors performed linkage analysis in 39 families with autosomal recessive early-onset PD (AR-EOPD) negative for parkin and DJ-1 mutations. Eight families including three Japanese, two Taiwanese, one Turkish, one Israeli, and one Philippine showed evidence of linkage with PARK6 with multipoint log of the odds (lod) score of 9.88 at D1S2732. The results indicate worldwide distribution of PARK6-linked parkinsonism.

Age of Onset↗

PubMed2004

Symptoms in relation to chemicals and dampness in newly built dwellings.

OBJECTIVES: As the airtightness of dwellings has recently increased, problems associated with indoor air pollution and dampness have become important environmental health issues. The aim of this study was to clarify whether symptoms in residents living in newly built dwellings were related to chemicals and dampness. METHODS: Symptoms of 317 residents were surveyed by standardized questionnaires, and the concentrations of formaldehyde, acetaldehyde, and 17 volatile organic compounds (VOCs) in their homes were measured. Dampness (condensation on window panes and/or walls, and mold growth) was identified by questionnaires given to the householders or their partners. RESULTS: Some VOCs (toluene, butyl acetate, ethylbenzene, alpha-pinene, p-dichlorobenzene, nonanal, and xylene) were significantly related to the symptoms, and the sum of all VOCs (all identified VOCs) was significantly related to throat and respiratory symptoms [odds ratio (OR) for eye symptoms =2.4; 95% confidence interval (CI) 1.0-5.5], although the concentrations of VOCs were relatively low. As for the dampness index, condensation on window panes and/or walls was related to all symptoms, and mold growth was related to all symptoms except skin, throat and respiratory and general symptoms. As the number of dampness signs increased, the ORs increased for the symptoms except general symptoms (OR for nose symptoms = 4.4, 95% CI 1.6-11.9). CONCLUSION: Both VOCs and dampness were significantly related to symptoms. We should take measures to reduce the concentrations of VOCs, dampness and microbial growth in dwellings.

Acetaldehyde↗

PubMed2004

Enzymatic synthesis of a catechin conjugate of polyhedral oligomeric silsesquioxane and evaluation of its antioxidant activity.

The antioxidant activity of catechin was amplified by conjugation with amine-terminated polyhedral oligomeric silsesquioxane (POSS) using horseradish peroxidase as catalyst. Compared to intact catechin, the scavenging activity of the POSS-catechin conjugate against superoxide anion was greatly improved. In addition, the conjugate strongly inhibited xanthine oxidase activity.

Antioxidants↗

PubMed2004

Multiseptate gallbladder: diagnostic value of MR cholangiography and ultrasonography.

Multiseptate gallbladder is a rare congenital malformation. We present a case that emphasizes the importance of ultrasonography and magnetic resonance imaging. Ultrasound examination of the abdomen showed multiple linear internal echoes consistent with multiple septa crossing the entire gallbladder lumen, creating a honeycomb appearance. Magnetic resonance cholangiopancreatography showed a grapelike cluster of the whole gallbladder.

Cholangiopancreatography, Endoscopic Retrograde↗

PubMed2004

Control of carrier density by self-assembled monolayers in organic field-effect transistors.

Organic thin-film transistors are attracting a great deal of attention due to the relatively high field-effect mobility in several organic materials. In these organic semiconductors, however, researchers have not established a reliable method of doping at a very low density level, although this has been crucial for the technological development of inorganic semiconductors. In the field-effect device structures, the conduction channel exists at the interface between organic thin films and SiO(2) gate insulators. Here, we discuss a new technique that enables us to control the charge density in the channel by using organosilane self-assembled monolayers (SAMs) on SiO(2) gate insulators. SAMs with fluorine and amino groups have been shown to accumulate holes and electrons, respectively, in the transistor channel: these properties are understood in terms of the effects of electric dipoles of the SAMs molecules, and weak charge transfer between organic films and SAMs.

Computer Simulation↗

PubMed2004

Antibacterial and antipeptide antibodies in Japanese and Finnish patients with rheumatoid arthritis.

It has been suggested that Proteus infection may be involved in the pathogenesis of rheumatoid arthritis (RA). Bacterial and peptide immune responses in patients with RA and other control subjects were investigated in two geographically different populations. Serum samples from Finnish patients with early ( n=72) and advanced ( n=27) RA and 30 Finnish healthy controls, as well as from Japanese RA patients from two different locations: Tokyo ( n=30) and Otsu ( n=30), 18 patients with systemic lupus erythematosus (SLE) and 23 Japanese healthy controls were all screened for the total, and class-specific (IgG, IgA and IgM) antibodies against Proteus mirabilis, Escherichia coli and Serratia marcescens by indirect immunofluorescence assay. These samples were also tested for the determination of levels of isotypic antibodies against the shared epitope involving 16-mer synthetic peptides containing the EQRRAA or ESSRAL sequences and compared to scrambled control peptide by using an enzyme-labeled immunosorbent assay method. Significantly elevated levels of IgG and IgM antibodies to P. mirabilis and antibodies against both EQRRAA and ESSRAL peptides were detected in sera of Finnish patients with early and advanced RA, and in Japanese patients from Otsu or Tokyo compared to their corresponding control groups. In contrast, no difference either in the total or in any of the isotypic antibodies were observed between these groups when serum samples were screened against each of E. coli and S. marcescens or against the control peptide. Furthermore, there was a significant correlation between the antibody levels against Proteus bacteria only and both EQRRAA and ESRRAL peptides. Our findings support the possibility for specific involvement of P. mirabilis in the etiopathogenesis of RA even in early cases.

Antibodies, Anti-Idiotypic↗

PubMed2004

Recent evolutionary origin within the primate lineage of two pseudogenes with similarity to members of the transforming growth factor-beta superfamily.

Using a search engine called Motifer, we searched the public database of the human genome for genes matching a consensus pattern of cysteine residues derived from members of the transforming growth factor-beta (TGF-beta) superfamily. We identified two genes (named MDF451 and MDF628) that display sequence similarity to members of the TGF-beta superfamily in the arrangement of six conserved cysteine residues. Phylogenetic analyses revealed that MDF451 and MDF628 constitute a distinct subgroup within the TGF-beta superfamily, distantly related to the GDNF subfamily of ligands. Both genes could be identified in several primate species in addition to human, including chimpanzee, gorilla, guereza, and green and gray monkey, but not in rodents or other non-primate mammals, and appear not to be present in the genomes of mouse, rat or zebrafish. RNAs for MDF451 and MDF628 were expressed at low levels within distinct regions of the human central nervous system, including adult cerebellum, adult spinal cord and fetal brain. Despite expression at the RNA level, both genes presented a transcribed upstream stop codon that would prevent translation of the TGF-beta-like reading frame. The coding potential of alternative reading frames was not immediately apparent. The two genes may represent TGF-beta-like pseudogenes that have recently appeared in evolution in a common ancestor of the primate lineage by duplication from a GDNF/TGF-beta-like ancestral gene.

Amino Acid Sequence↗

PubMed2004

An experimental model for amoebic abscess production in the cheek pouch of the Syrian golden hamster, Mesocricetus auratus.

A new experimental model was developed in hamsters for amoebic abscess caused by Entamoeba histolytica. E. histolytica trophozoites were cultured in a liquid axenic medium, and then injected intradermally into the cheek pouch of the Syrian golden hamster, Mesocricetus auratus. Inoculation consistently resulted in abscess formation at the site in 20 of 22 (91%) study animals. The amoebic nature of the abscesses was confirmed by light microscopy and histopathologic examination. Abscess formation was maximal at day 12 post-inoculation. Potential applications of this simple and reliable model include further elucidation of the pathogenesis of invasive amoebiasis, studies of the host response to amoebae, and in vivo evaluation of chemotherapeutic agents that show in vitro efficacy against E. histolytica.

Amebiasis↗

PubMed2004

Inducible expression of p57KIP2 inhibits glioma cell motility and invasion.

To examine the role of p57KIP2 in human malignant glioma cells, we studied its expression in a panel of human malignant glioma specimens by western blot and immunohistochemical analysis. To determine the effects of p57KIP2 expression on the phenotype of glioma cells, we analyzed two inducible stably transfected p57KIP2 expressing glioma cell lines. Expression of p57KIP2 was induced in U373 and U87 malignant glioma cells with doxycycline using the tetracycline repressor system. A phagokinetic track assay on gold particles was used to investigate differences in cell migration between p57KIP2 expressing and non-expressing control cells. The effects of the extracellular matrix (ECM) on U373 motility was determined in p57+ and p57-cells on surfaces coated with 5 microg/cm2 of fibronectin, laminin, type I and type IV collagens. The invasion of p57+ and p57- glioma cells across BD Biocoat Matrigel invasion chambers was then determined. p57KIP2 was weakly expressed in 4/6 glioblastoma (GBM) specimens by western blot. By immunohistochemistry, p57KIP2 immunoreactivity was positive in 8/40 GBMs, and was primarily nuclear in location. The motility of U373 glioma cells was significantly reduced after p57KIP2 induction. The presence of ECM proteins did not further alter the motility of p57+ and p57- glioma cells. The results of the invasion chamber assay showed that p57+ cells exhibited a 35% reduction in their invasive capacity as compared to p57- cells. These data suggest that p57KIP2 is expressed in at least some malignant gliomas. Inducible expression of 57KIP2 in cell lines deficient in this cyclin-dependent kinase inhibitor reduces their otility and invasiveness.

Blotting, Western↗