Biomedical subjects

Yusuke Suzuki

Publications and source records attributed to Yusuke Suzuki.

At least 19 recordsLinked to original sources

PubMed2007

TLR3-mediated synthesis and release of eotaxin-1/CCL11 from human bronchial smooth muscle cells stimulated with double-stranded RNA.

Respiratory infections with RNA viruses, such as rhinovirus or respiratory syncytial virus, are a major cause of asthma exacerbation, accompanied by enhanced neutrophilic and/or eosinophilic inflammation of the airways. We studied the effects of dsRNA synthesized during RNA virus replication, and of its receptor, TLR3, on the synthesis of eosinophilic chemokines in bronchial smooth muscle cells (BSMC). Synthetic dsRNA, polyinosinic-cystidic acid (poly(I:C)), induced the synthesis of eosinophilic chemokines, eotaxin-1/CCL11 and RANTES/CCL5, from primary cultures of human BSMC, and IL-4 increased synergistically the synthesis of poly(I:C)-induced CCL11. A robust eosinophil chemotactic activity was released from BSMC stimulated with poly(I:C) and IL-4, which was mostly inhibited by preincubation with an anti-CCL11, but not with an anti-CCL5 Ab. Although the immunoreactivity of TLR3 was detectable on the cellular surface of BSMC by flow cytometric analysis, pretreatment with an anti-TLR3-neutralizing Ab failed to block the poly(I:C)-induced synthesis of CCL11. We have determined by confocal laser-scanning microscopy that the immunoreactivity of TLR3 was aggregated intracellularly in poly(I:C)-stimulated BSMC, colocalizing with fluorescein-labeled poly(I:C). The synthesis of CCL11 was prominently inhibited by the transfection of TLR3-specific small interfering RNA or by bafilomycin A1, an endosomal acidification inhibitor, further supporting the essential role played by intracellular TLR3 in the synthesis of poly(I:C)-induced CCL11 in BSMC. In conclusion, these observations suggest that, by activating intracellular TLR3 in BSMC, respiratory RNA virus infections stimulate the production of CCL11 and enhance eosinophilic inflammation of the airways in the Th2-dominant microenvironment.

Bronchi↗

PubMed2006

Fcgamma receptor deficiency confers protection against atherosclerosis in apolipoprotein E knockout mice.

IgG Fc receptors (FcgammaRs) play a role in activating the immune system and in maintaining peripheral tolerance, but their role in atherosclerosis is unknown. We generated double-knockout (DKO) mice by crossing apolipoprotein E-deficient mice (apoE(-/-)) with FcgammaR gamma chain-deficient mice (gamma(-/-)). The size of atherosclerotic lesions along the aorta was approximately 50% lower in DKO compared with apoE(-/-) control mice, without differences in serum lipid levels. The macrophage and T-cell content of lesions in the DKO were reduced by 49+/-6% and 56+/-8%, respectively, compared with the content in apoE(-/-) lesions. Furthermore, the expression of monocyte chemoattractant protein-1 (MCP-1), RANTES (Regulated on Activated Normal T-cell Expressed and Secreted), and intercellular adhesion molecule-1 (ICAM-1) and the activation of nuclear factor-kappaB (NF-kappaB) were significantly reduced in aortic lesions from DKO mice. In vitro, vascular smooth muscle cells (VSMCs) from both gamma(-/-) and DKO mice failed to respond to immune complexes, as shown by impaired chemokine expression and NF-kappaB activation. ApoE(-/-) mice have higher levels of activating FcgammaRI and FcgammaRIIIA, and inhibitory FcgammaRIIB, compared with wild-type mice. The DKO mice express only the inhibitory FcgammaRIIB receptor. We conclude that FcgammaR deficiency limits development and progression of atherosclerosis. In addition to leukocytes, FcgammaR activation in VSMCs contributes to the inflammatory process, in part, by regulating chemokine expression and leukocyte invasion of the vessel wall. These results underscore the critical role of FcgammaRs in atherogenesis and support the use of immunotherapy in the treatment of this disease.

Animals↗

PubMed2006

Identification and characterization of an increased glycoprotein in aging: age-associated translocation of cathepsin D.

We found that 14 N-glycosylated proteins were accumulated in the rat cerebral cortex cytosolic fraction in the aging process by a comparative study with two-dimensional gel electrophoresis and concanavalin A staining. All proteins had high mannose and/or hybrid-type N-glycans, as indicated by the fact that they were sensitive to endoglycosidase H digestion. Three of these cytosolic glycoproteins were identified as cathepsin D, a lysosomal protease, by tryptic digestion and nano liquid chromatography electrospray ionization quadrupole time of flight mass spectrometry. The increase of cytosolic cathepsin D during aging was not due to lysosomal membrane disruption, as shown by the fact that the activities of beta-hexosaminidase and beta-glucuronidase, other lysosomal enzymes, did not increase in the cytosolic fraction. Although the total amount of cathepsin D increased during aging, the amount of cathepsin D in the microsomal fraction did not change, indicating a selective increase of cytosolic cathepsin D. This phenomenon was also observed in the hippocampus, cerebellum, kidney, liver, and spleen. Based on these results, we propose that cytosolic cathepsin D is a new biomarker of aging.

Aging↗

PubMed2006

Structural characterization of neutral glycosphingolipids by thin-layer chromatography coupled to matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight MS/MS.

Rapid and convenient structural analysis of neutral glycosphingolipids (GSLs) was achieved by direct coupling of thin-layer chromatography (TLC) to matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight (MALDI-QIT-TOF) MS/MS. Positions of unstained GSL spots on developed TLC plates were determined by comparison to orcinol-stained references. A matrix solution of 2,5-dihydroxybenzoic acid (DHB) in acetonitrile/water (1:1 v/v) was then added directly to the unstained GSL spots, and the GSLs were directly analyzed by MALDI-QIT-TOF MS. The acetonitrile/water DHB solution proved to be suitable for MS/MS structural analysis with high sensitivity. MS/MS and MS/MS/MS of GSLs yielded simple and informative spectra that revealed the ceramide and long-chain base structures, as well as the sugar sequences. Hydroxy fatty acids in ceramide provided characteristic MS/MS fragment ions. GSLs were stained with primuline, a nondestructive dye, after TLC development, and successfully analyzed by MALDI-QIT-TOF MS/MS with high sensitivity. Immunostaining of GSLs after TLC development is a powerful method for characterizing antibody-specific sugars, but not ceramides. By coupling TLC-immunostaining of GSLs to MALDI-QIT-TOF MS/MS, we were able to identify both the sugar and the ceramide structures. The detection limits of asialo GM1 (Galbeta1-3GalNAcbeta1-4Galbeta1-4Glcbeta1-1'Cer) were 25 and 50 pmol in primuline staining and immunostaining, respectively.

Chromatography, Thin Layer↗

PubMed2006

Attitudes toward disclosing the diagnosis of dementia in Japan.

BACKGROUND: The rapid increase in the elderly population in Japan has triggered a debate on whether or not patients with dementia should be informed of their diagnosis. The purpose of the present study was to investigate the attitudes of people in a large city in Japan toward the disclosure of a diagnosis of dementia. METHODS: In Study 1, 2000 residents aged 40-64 and 5000 residents aged 65 and over were sampled randomly, and a structured questionnaire was sent to them by mail. In Study 2, we administered a structured interview-based questionnaire to 3949 randomly enrolled residents of Nagoya City aged 45 and over whose family member had been certified as needing long-term care. RESULTS: In Study 1, 79.8% of the younger respondents (n = 710) stated that they would prefer the disclosure of a hypothetical diagnosis of dementia, as did 75.5% of the older respondents (n = 2162). Furthermore, 85.1% (n = 749) of the younger respondents and 82.5% (n = 2181) of the older respondents stated that they would prefer that the patient be told his or her hypothetical diagnosis of dementia. In Study 2, in the case of care recipients without dementia, 68.3% (n = 650) of their family members preferred disclosure of a hypothetical diagnosis of dementia. Among the families of care recipients who had dementia, 58.4% (n = 301) of family members preferred disclosure. CONCLUSIONS: The present survey of caregivers and non-caregivers in an urban city of Japan demonstrated that the desire for disclosure of a diagnosis of dementia is relatively high.

Adult↗

PubMed2006

Parthenolide modulates the NF-kappaB-mediated inflammatory responses in experimental atherosclerosis.

OBJECTIVE: Activation of transcription factor NF-kappaB is an important step in the development of vascular damage, because it controls inducible genes, including many inflammatory mediators. The pharmacological modulation of this process is the main objective in the design of new therapies for atherosclerosis. In this work we analyzed the effects of the natural compound parthenolide (PTN), an NF-kappaB inhibitor. METHODS AND RESULTS: In vascular smooth muscle cells (VSMCs) and monocytes stimulated with lipopolysaccharide (LPS), nontoxic doses of PTN reduced IkappaBalpha degradation, NF-kappaB activation, and MCP-1 expression, without inhibiting AP-1 and MAPK. In apoE mice, treatment with low (2 mg/kg, 20 weeks), medium (4 mg/kg, 10 weeks), and high (10 mg/kg, 10 weeks) dose of PTN reduced the size of aortic lesion, decreased macrophage, and increased VSMC content in the lesions. Treated mice showed reduced serum levels of MCP-1 and attenuated NF-kappaB activity, but not AP-1, in the lesions. Moreover, PTN affects neither apoptotic cell death nor oxidative stress in cultured cells and mice. CONCLUSIONS: NF-kappaB inhibition by PTN retards atherosclerotic lesions in apoE mice, by reducing lesion size and changing plaque composition. This natural compound could represent a novel therapeutic approach to inflammation during vascular damage.

Animals↗

PubMed2006

Regulation of insect steroid hormone biosynthesis by innervating peptidergic neurons.

In insects, steroid hormones named ecdysteroids elicit molting and metamorphosis. The prothoracic gland (PG) is a predominant source of ecdysteroids, where their biosynthesis (ecdysteroidogenesis) is regulated by several neuropeptides. Here, we report that FMRFamide-related peptides (FaRPs) regulate ecdysteroidogenesis through direct innervation of the PG in the silkworm Bombyx mori. We purified a previously uncharacterized Bombyx FaRP, DPSFIRFamide, and identified the corresponding Bombyx FMRFamide gene (Bommo-FMRFamide, BRFa), which encodes three additional FaRPs. All BRFa peptides suppressed ecdysteroidogenesis in the PG by reducing cAMP production by means of the receptor for Bommo-myosuppressin, another FaRP we have previously shown to act as a prothoracicostatic factor. BRFa is predominantly expressed in neurosecretory cells of thoracic ganglia, and the neurons in the prothoracic ganglion innervate the PG to supply all four peptides to the gland surface. Electrophysiological recordings during development confirmed the increased firing activity of BRFa neurons in stages with low PG activity and decreased ecdysteroid levels in the hemolymph. To our knowledge, this study provides the first report of peptides controlling ecdysteroidogenesis by direct innervation.

Amino Acid Sequence↗

PubMed2006

Which two questions of Mini-Mental State Examination (MMSE) should we start from?

The MMSE is a simple and commonly used instrument to evaluate cognitive impairment. With the aim of enabling the examiner to skip a large portion of the MMSE when screening subjects with lower possibility of cognitive impairment, we examined the internal distribution of the MMSE scores among 792 older adults visiting a teaching hospital, a long-term care hospital, nursing homes, and a geriatric clinic. The correlation coefficients between the summed scores of any two items of MMSE and the total score were compared. A receiver operating characteristic (ROC) curve was drawn to show the sensitivity and the specificity of predicting cognitive impairment, which was defined by the total MMSE score being less than 24. The mean MMSE score was 20.5 +/- 6.9 (+/-S.D.). A good predictor for cognitive impairment was the summed scores of the time orientation and serial sevens with a sensitivity of 98.2% and a specificity of 69.2% if cut-off was set at 7/7+. This finding appears to help streamline the screening process for cognitive impairment in general elderly population.

Aged↗

PubMed2006

Hydromechanical stress in shake flasks: correlation for the maximum local energy dissipation rate.

Shake flasks are widely used in biotechnological process research. Bioprocesses for which hydromechanical stress may become the rate controlling parameter include those where oils are applied as carbon sources, biotransformation of compounds with low solubility in the aqueous phase, or processes employing animal, plant, or filamentous microorganisms. In this study, the maximum local energy dissipation rate as the measure for hydromechanical stress is characterized in shake flasks by measuring the maximum stable drop size. The theoretical basis for the method is that the maximum stable drop diameter in a coalescence inhibited liquid/liquid dispersion is only a function of the maximum local energy dissipation rate and not of the dispersing apparatus. The maximum local energy dissipation rate is obtained by comparing the drop diameters in shake flasks to those in a stirred tank reactor. At the same volumetric power consumption, the maximum energy dissipation rate in shake flasks is about 10 times lower than in stirred tank reactors explaining the common observation of considerable differences in the morphology of hydromechanically sensitive cells between these two reactor types. At the same volumetric power consumption, the maximum local energy dissipation rate in baffled and in unbaffled shake flasks is very similar. A correlation is presented to quantify the maximum local energy dissipation rate in shake flasks as a function of the operating conditions. Non-negligible drop viscosity may be considered by known literature correlations. Further, from dispersion experiments a critical Reynolds number of about 60,000 is proposed for turbulent flow in unbaffled shake flasks.

Algorithms↗

PubMed2006

D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol alters cellular cholesterol homeostasis by modulating the endosome lipid domains.

D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP) is a frequently used inhibitor of glycosphingolipid biosynthesis. However, some interesting characteristics of D-PDMP cannot be explained by the inhibition of glycolipid synthesis alone. In the present study, we showed that d-PDMP inhibits the activation of lysosomal acid lipase by late endosome/lysosome specific lipid, bis(monoacylglycero)phosphate (also called as lysobisphosphatidic acid), through alteration of membrane structure of the lipid. When added to cultured fibroblasts, D-PDMP inhibits the degradation of low-density lipoprotein (LDL) and thus accumulates both cholesterol ester and free cholesterol in late endosomes/lysosomes. This accumulation results in the inhibition of LDL-derived cholesterol esterification and the decrease of cell surface cholesterol. We showed that D-PDMP alters cellular cholesterol homeostasis in a glycosphingolipid-independent manner using L-PDMP, a stereoisomer of D-PDMP, which does not inhibit glycosphingolipid synthesis, and mutant melanoma cell which is defective in glycolipid synthesis. Altering cholesterol homeostasis by D-PDMP explains the unique characteristics of sensitizing multidrug resistant cells by this drug.

1-Deoxynojirimycin↗

PubMed2006

Structural characterization of glycopeptides by N-terminal protein ladder sequencing.

High-sensitivity and high-throughput mass spectrometry (MS) has become an important tool for characterizing glycopeptides. Here, we analyzed synthetic O-linked glycopeptides using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS. First, we applied MALDI-quadrupole ion trap (QIT)-TOF MS, which enables collision-induced dissociation-MSn analysis for fine structural characterization. Subsequent MS/MS of sodium adduct ions selected as precursor ions yielded detailed information about the site of oligosaccharide attachment as well as the carbohydrate and amino acid sequences; however, these MS/MS spectra were very complex. To obtain easily interpretable and simple spectra, we used N-terminal protein ladder sequencing coupled with MALDI-TOF MS. From the extremely simple resulting spectra, we were able to determine the glycosylation sites, amino acid sequences, and oligosaccharide molecular weights of the glycopeptides.

Amino Acid Sequence↗

PubMed2006

Behavioral, psychological and physical symptoms in group homes for older adults with dementia.

BACKGROUND: Despite the recent dissemination of group homes in Japan for older adults with dementia, the behavioral and psychological features of the residents remain unknown. To clarify the association of such features with the levels of difficulty encountered by caregivers in coping with these symptoms, we have conducted a survey to compare the frequencies of the symptoms among group homes, nursing homes and a long-term care hospital. METHODS: Five hundred and eighty-six older adults aged 65 years or more were sampled. Data were consecutively collected from questionnaires given to the caregivers. The questionnaire included basic activities of daily living, the Mini-mental State Examination, frequencies of behavioral, psychological and physical symptoms, and the levels of difficulty in coping with the symptoms. RESULTS: In group homes, requests to go home, urinary incontinence and frequent complaining were the most commonly observed symptoms. The symptoms associated with disorientation, anxiety and depression were frequently observed in all three care settings. Most of the symptoms were more frequently observed in group homes than in the other two care settings. However, the levels of difficulty in coping with most of the symptoms were the highest in the long-term care hospital, followed in order by the group homes and nursing homes. In group homes, inappropriate sexual behavior was the symptom creating the most stress for the caregivers, followed by verbal and nonverbal abuse and changeable mood. CONCLUSIONS: The symptomatic traits of residents in group homes were clarified in the present study. These findings could be helpful in considering desirable placement or the improvement of eligible service provision for older adults with dementia in care facilities.

Aged↗

PubMed2006

A major urinary protein of the domestic cat regulates the production of felinine, a putative pheromone precursor.

Domestic cats spray urine with species-specific odor for territorial marking. Felinine (2-amino-7-hydroxy-5,5-dimethyl-4-thiaheptanoic acid), a putative pheromone precursor, is excreted in cat urine. Here, we report that cauxin, a carboxylesterase excreted as a major urinary component, regulates felinine production. In vitro enzyme assays indicated that cauxin hydrolyzed the felinine precursor 3-methylbutanol-cysteinylglycine to felinine and glycine. Cauxin and felinine were excreted age dependently after 3 months of age. The age-dependent increases in cauxin and felinine excretion were significantly correlated. In mature cats, cauxin and felinine levels were sex-dependently correlated and were higher in males than in females. In headspace gas of cat urine, 3-mercapto-3-methyl-1-butanol, 3-mercapto-3-methylbutyl formate, 3-methyl-3-methylthio-1-butanol, and 3-methyl-3-(2-methyldisulfanyl)-1-butanol were identified as candidates for felinine derivatives. These findings demonstrate that cauxin-dependent felinine production is a cat-specific metabolic pathway, and they provide information for the biosynthetic mechanisms of species-specific molecules in mammals.

Animals↗

PubMed2006

Convenient structural analysis of glycosphingolipids using MALDI-QIT-TOF mass spectrometry with increased laser power and cooling gas flow.

Matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry (MALDI-QIT-TOF MS) was applied to the structural characterization of neutral glycosphingolipids. Lithium adduct ions of glycosphingolipids were analyzed using MALDI-QIT-TOF MS under strong conditions of increased laser power and cooling gas flow. The relative intensities of fragment ions were increased under the strong conditions, and the resulting spectra revealed the presence of oligosaccharide ions fragmented from the glycosphingolipids. Consequently, the oligosaccharide sequences of the glycosphingolipids were readily obtained. To obtain more detailed structural information, MS/MS (MS2) and MS/MS/MS (MS3) analyses were performed with selection of the lactosylceramide and ceramide ions, respectively. The resulting data were sufficient to determine the structures of both the oligosaccharide and the ceramide moiety of each glycosphingolipid. The fragmentation patterns of MS2 and MS3 for Forssman glycolipid under the strong conditions were comparable to those of MS3 and MS4 obtained under standard conditions, respectively. Thus, MALDI-QIT-TOF MS with increased laser power and cooling gas flow is a convenient method for glycosphingolipid analysis.

Carbohydrate Sequence↗

PubMed2006

Underappreciated predictors for postdischarge mortality in acute hospitalized oldest-old patients.

BACKGROUND: Although oldest-old, those aged 85 years and older, patients are the fastest growing segment, clinical evidences regarding the acute care of oldest-old patients are still lacking. Because acute medical conditions requiring emergent hospitalization is frequently followed by high rate of progressive physical decline and increased mortality after discharge in oldest-old patients, prognostic information collected during hospitalization can provide the basis for discussion about the goals of care and therapy. The aim of our study was to identify predictive factors for postdischarge mortality in oldest-old patients. METHODS: The study included 403 oldest-old patients discharged from the acute care setting of a general hospital, who were followed-up for 1 year. Predictive values of the patients' characteristics collected during their hospitalization for 1-year mortality were identified utilizing Cox proportional hazard regression analysis. RESULTS: During 1-year follow-up, 104 patients (25.8%) died. The variables independently associated with 1-year mortality in multivariate analysis were the Charlson Comorbidity Index equal or greater than 2 [HR (hazard ratio) 4.71, 95%CI (confidence interval) 1.09-20.42], six or more prescribed medications at discharge (HR 3.12, 95% CI 1.39-6.99), benzodiazepines use (HR 1.64, 95% CI 1.04-2.60), nonsteroidal anti-inflammatory drugs use (HR 1.70, 95% CI 1.10-2.63), albumin less than or equaling 3.4 g/dl (HR 2.16, 95% CI 1.13-4.14), hemoglobin 10-12 g/dl (HR 2.32, 95% CI 1.22-3.56), hemoglobin less than 10 g/dl (HR 2.67, 95% CI 1.43-4.95), the presence of pressure sores (HR 1.84, 95% CI 1.14-2.97), and a history of delirium (HR 2.24, 95% CI 1.32-3.79). Functional impairment assessed by the Katz Index was only weakly associated with mortality (HR 1.24, 95% CI 0.53-2.91). CONCLUSION: Although often underappreciated, polypharmacy, particular medication use, anemia, the presence of pressure sores, and a history of delirium were important predictors for postdischarge mortality in oldest-old patients.

Aged, 80 and over↗

PubMed2006

A comparison of depressive mood of older adults in a community, nursing homes, and a geriatric hospital: factor analysis of Geriatric Depression Scale.

The Geriatric Depression Scale (GDS)-15 was used in 607 adults aged 65+ years living in a community, nursing homes, and a general hospital to explore characteristics of depressive mood in different care settings. Factor analysis of GDS-15 extracted 4 factors labeled unhappiness, apathy and anxiety, loss of hope and morale, and energy loss. The scale scores labeled unhappiness, apathy and anxiety, and loss of hope and morale were negatively correlated with the Barthel Index and the Mini-Mental State Examination scores. The results classified the depressive patterns into 2 types, one fitting the nursing home residents and the other fitting the hospital patients. The dominant factors of the nursing-home type were unhappiness and loss of hope and morale, and the hospital type was highly related with apathy and anxiety. The results indicate an extended utility of the GDS-15 for a deeper understanding of depressive mood in various care settings.

Activities of Daily Living↗

PubMed2006

[Role of specialists in geriatric medicine--overview of world trends--].

Rapid ageing of the society inevitably increases the demand for specialists in the healthcare of older people. Under these circumstances, how geriatricians work as specialists in the framework of healthcare services is becoming an urgent concern for those who are engaged in the healthcare for the elderly. Although some similarities can be identified in the development of geriatrics medicine across the countries, actual roles of geriatricians and the definitions of their specialties seem to vary depending on the healthcare systems of each country. Current issues related to the speciality of geriatric medicine are discussed.

Education, Medical↗

PubMed2006

Stimulation of the hippocampal glutamate receptor systems induces stress-like responses.

OBJECTIVE: The hypothalamic-pituitary-adrenal (HPA) axis controls glucocorticoid secretion and is in turn controlled by a diverse set of afferents in the brain. However, the precise mechanisms underlying these actions remain to be elucidated. In our previous study, a lesion in the entorhinal cortex, which is the major provider of glutamatergic innervation to the hippocampus, significantly attenuated the elevation of adrenocorticotropic hormone (ACTH) in plasma during immobilization stress. In the present study, we examined the effects of microinjections of glutamatergic agonists into the hippocampus on plasma ACTH and glucose concentrations. We also studied the interactions between glutamate and acetylcholine in this response in the hippocampus. MATERIALS AND METHODS: NMDA and AMPA subtypes of glutamate agonists were microinjected into the rat hippocampus, and ACTH and glucose levels in plasma were measured. The interaction between cholinergic and glutamatergic systems was investigated pharmacologically. RESULTS: Both the NMDA and AMPA subtypes of glutamate agonists induced elevations of plasma ACTH and glucose levels in a dose-dependent fashion. These responses were independent of those induced by activation of the hippocampal cholinergic system. CONCLUSION: Stimulation by the NMDA and AMPA subtypes of glutamate receptors in the hippocampus induced elevations of plasma ACTH and glucose, and these responses were independent of the cholinergic system.

Acetylcholine↗