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Biomedical subjects

K Maeda

Publications and source records attributed to K Maeda.

At least 109 records · Page 6Linked to original sources
PubMed2001

Mixed infection of Porphyromonas gingivalis and Bacteroides forsythus in a murine abscess model: involvement of gingipains in a synergistic effect.

Several microorganisms including Porphyromonas gingivalis and Bacteroides forsythus have been implicated to be etiologically important agents of periodontal disease. In this study, we determined the ability of combinations of periodontopathogenic microorganisms to cause tissue destruction in a murine abscess model. Although all bacterial combinations used in this study produced larger abscesses than did monoinfection of each bacterium, the combination of P. gingivalis and B.forsythus showed a synergistic effect on abscess formation. Since these two bacteria have been frequently found together in lesions of periodontitis, these results suggest the significance of their co-infection in the progression of periodontitis. P. gingivalis produces extracellular and cell-associated cysteine proteinases (gingipains) which appear to be involved in its virulence. The rgpA rgpB double and kgp mutants induced significantly smaller abscesses than the wild type. Moreover, the rgpA rgpB kgp triple (gingipain-null) mutant hardly showed lesion formation at all with the experimental conditions used in this study, indicating that these genes encoding gingipains are important for virulence of P. gingivalis. Mixed infection of these P. gingivalis mutants with B. forsythus showed an additive effect on abscess formation, indicating that the gingipains of P. gingivalis may play an important role in the pathological synergism between P. gingivalis and B. forsythus.

Abscess↗
PubMed2001

The expression of SPARC in adipose tissue and its increased plasma concentration in patients with coronary artery disease.

OBJECTIVE: Adipocytes secrete various cytokines and matrix proteins. Several of them precipitate in obesity-associated diseases, including atherosclerosis. In the current study, we have examined the expression of secreted protein, acidic and rich in cysteine (SPARC) in adipose tissue and its significance in obesity and coronary artery disease (CAD). RESEARCH METHODS AND PROCEDURES: The SPARC mRNA expressions both in vivo and in vitro were detected by Northern blot analysis. Plasma SPARC concentrations were measured by enzyme immunosorbent assay. First, we investigated the plasma SPARC levels of 88 unrelated adult Japanese subjects (62 men and 26 women; average age: [+/- SD] 50 +/- 12 years; body mass index [BMI]: 16 to 46 kg/m(2)). Additionally 31 subjects with CAD diagnosed by coronary angiography (20 men and 11 women) were also investigated. RESULTS: Human adipose tissues expressed abundant SPARC mRNA. SPARC expression in adipose tissues was upregulated in obese db/db mice. Markedly enhanced expression of SPARC mRNA was observed in 3T3-L1 fibroblasts during adipocyte differentiation. Consistent with these results, plasma SPARC levels proved a positive correlation with BMI in humans (r = 0.27; p < 0.01). Interestingly, plasma SPARC concentrations were significantly elevated in age- and BMI-matched subjects with CAD (p < 0.05). DISCUSSION: SPARC was expressed in adipose tissues and its expression was enhanced in obese mice. In human, plasma SPARC levels were elevated in obesity and CAD patients. This elevated SPARC may be involved in the progression of CAD.

Adipose Tissue↗
PubMed2001

3beta-hydroxy-delta5 -C27-steroid dehydrogenase deficiency: diagnosis and treatment.

The aim of this study was to evaluate the effects of bile acid treatment and to obtain further information about the pathway of bile acid biosynthesis in a patient with 3beta-hydroxy-delta5-C27-steroid dehydrogenase/isomerase (3beta-HSD) deficiency by gas chromatography-mass spectrometry. Results showed that at 2 months of age, 3beta-hydroxy-5-cholen-24-oic acid (3.0 micromol/mmol Cr, 7.9%) was detected in the urine in essentially the same relative amount as 3beta,7alpha-dihydroxy- and 3beta,7alpha,12alpha-trihydroxy-5-cholen-24-oic acids (3.7 micromol/mmol Cr, 9.8%) during ursodeoxycholic acid treatment combined with prednisolone. As a result, diagnosis was delayed until 18 months of age. One month later with substitution of chenodeoxycholic acid treatment, urinary 3beta,7alpha-dihydroxy- and 3beta,7alpha,12alpha-trihydroxy-5-cholen-24-oic acids decreased significantly, and subsequent improvement of liver dysfunction was accelerated. Chenodeoxycholic acid treatment is useful in 3beta-HSD deficiency. However, in the diagnosis of this disease in early life, it should be noted that the acidic pathway may be the major route for bile acid biosynthesis in the neonatal period. Diagnosis of 3beta-HSD deficiency may have been delayed by administration of ursodeoxycholic acid, resulting in prolonged diagnostic investigation in this child with cholestasis. Further, use of prednisolone may have been contraindicated.

3-Hydroxysteroid Dehydrogenases↗
PubMed2001

Expression of Rho-family GTPases (Rac, cdc42, RhoA) and their association with p-21 activated kinase in adult rat peripheral nerve.

To clarify the presence of the Rho family of small GTPases p21-activated kinase (pak) signaling pathway in the PNS, we have examined their expression, the association between the small GTPases and pak and the pak kinase activity in the PNS using immunoblot analysis, immunohistochemistry, co-immunoprecipitation study, and in vitro kinase assay. Immunoblot analysis showed the expression of Rac, cdc42, RhoA and pak in the dorsal root ganglion (DRG) and sciatic nerve. The localization of these proteins in the DRG neurons and axons and Schwann cells of the sciatic nerve was confirmed by immunohistochemistry. Co-immunoprecipitation studies indicated the in vivo associations of pak with Rac and cdc42, but not with RhoA, in both the DRG and sciatic nerve. The autophosphorylation of pak and phosphorylation of histone H4 by pak were also found in the DRG and sciatic nerve as well as in the CNS. These results suggest that the Rac/cdc42-pak signaling pathway exists and functions in the PNS and may mediate some intracellular signals.

Animals↗
PubMed2001

Mass spectrometry proves under-O-glycosylation of glomerular IgA1 in IgA nephropathy.

BACKGROUND: The IgA1 molecule, which is predominantly deposited in glomeruli in IgA nephropathy (IgAN), is a unique serum glycoprotein because it has O-glycan side chains in its hinge region. Our study was conducted to investigate the O-glycan structure in the glomerular IgA1 in IgAN. METHODS: The IgA1 was separated from 290 renal biopsy specimens of 278 IgAN patients and from four serum IgA1 samples (IgAN, 2; control, 2). The variety of O-glycan glycoform was determined by estimating the precise molecular weights of the IgA1 hinge glycopeptides using matrix-assisted laser desorption ionization time of flight mass spectrometry. RESULTS: The peak distribution of IgA1 hinge glycopeptides clearly shifted to lesser molecular weights in both glomerular and serum IgA1 in IgAN compared with the serum IgA1 of controls. In the five major peaks of IgA1 hinge glycopeptides in each sample, the numbers of carbohydrates composing O-glycans (GalNAc, Gal, and NANA) in the deposited and serum IgA1 in IgAN patients were significantly fewer than those in the serum IgA1 in the control groups. CONCLUSION: The O-glycan side chains in the hinge of the glomerular IgA1 were highly underglycosylated in IgAN. These results indicate that the decreased sialylation and galactosylation of the IgA1 hinge glycopeptides play a crucial role in its glomerular deposition in IgAN.

Adult↗
PubMed2001

Reduction of serum interferon (IFN)-gamma concentration and lupus development in NZBxNZWF(1)mice by lactic dehydrogenase virus infection.

The complexity of cytokine regulation and the imbalance of helper T (Th)1 and Th2 subsets in systemic lupus erythematosus (SLE) animal models and human SLE are well recognized. In this study in NZBxNZWF(1)mice, the effects of lactic dehydrogenase virus (LDV) infection on the production of interferon (IFN)-gamma in the serum and the development of autoimmune disease were examined. The progress of the disease (the development of glomerulonephritis, formation of glomerular IgG and C3 deposits, increase in the blood urea nitrogen values, and mortality) was parallel with an increase in serum IFN-gamma in uninfected NZBxNZWF(1)mice. These changes were inhibited in LDV-infected NZBxNZWF(1)mice. Our findings suggest that increase in serum IFN-gamma may be associated with the active disease in NZBxNZWF(1)mice.

Animals↗
PubMed2001

A new approach to the treatment of congenital tracheal stenosis: Balloon tracheoplasty and expandable metallic stenting.

BACKGROUND/PURPOSE: Many surgical procedures have been unsatisfactory for the treatment of congenital tracheal stenosis. The authors used intraluminal balloon dilatation and expandable metallic airway stent for this condition. METHODS: From 1997 to 2000, balloon expandable stents (Palmaz) were inserted into the trachea in 5 infants, aged 7 days to 12 months who had severe airway obstruction caused by tracheal stenosis. Tracheal stents were placed after intraluminal balloon dilatation of complete tracheal rings. The stents were placed on balloon catheters and were inserted into the desired position bronchoscopically using x-ray control. They were expanded and fixed in place by inflating the balloon to appropriate diameter. The stents were 10 to 40 mm long and 6 to 8 mm in diameter. RESULTS: Four patients have been relieved of airway obstruction after this procedure. One patient died after 9 months of palliation. In all patients, granulation tissue developed over the stents and could be managed by scraping or balloon compression. Stents have been in place for 9 to 36 months after insertion without any other complication. CONCLUSIONS: Airway stents after balloon tracheoplasty can be left for prolonged periods to relieve tracheal obstruction. This technique may provide an important remedy in infants and children with congenital tracheal stenosis.

Airway Obstruction↗
PubMed2001

Relationship between plasma levels of cardiac natriuretic peptides and soluble Fas: plasma soluble Fas as a prognostic predictor in patients with congestive heart failure.

BACKGROUND: Cardiac natriuretic peptides may induce apoptosis in myocytes; however, the relationship between plasma levels of cardiac natriuretic peptides and those of soluble Fas (sFas) and tumor necrosis factor (TNF)-alpha remains unknown in patients with congestive heart failure (CHF). METHODS AND RESULTS: We measured plasma levels of sFas and TNF-alpha and those of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), norepinephrine, and endothelin 1 in 96 patients with CHF (ejection fraction < 45%). The patients were monitored for 3 years. Plasma levels of sFas and TNF-alpha increased with the severity of CHF. There was no significant correlation between sFas plasma levels and those of ANP and BNP. Cox proportional hazard analysis showed that high levels of sFas (P = .009) and BNP (P < .0001) and a low ejection fraction (P = .019) were independent significant prognostic predictors. CONCLUSIONS: There is no significant correlation between cardiac natriuretic peptide and sFas levels in plasma. Plasma sFas is a useful prognostic marker independent of neurohumoral factors, suggesting that immune activation and/or apoptosis play a significant role in the pathogenesis of CHF.

Age Factors↗
PubMed2001

Comparison of neurohumoral effects of short-acting and long-acting loop diuretics in patients with chronic congestive heart failure.

We evaluated the comparative effects of furosemide, a short-acting loop diuretic, and azosemide, a long-acting loop diuretic, on neurohumoral factors and quality of life (QOL) in patients with congestive heart failure (CHF). Twenty-five stable patients with mild chronic CHF who had been administered furosemide (n = 14) or azosemide (n = 11) orally for more than 3 months were studied. We changed furosemide to azosemide or azosemide to furosemide and followed for 3 months. Echocardiography was performed, and we also measured neurohumoral factors and assessed QOL by questionnaire. Blood pressure, body weight, renal function and echocardiographic findings were the same during the furosemide and azosemide treatments. Plasma levels of atrial natriuretic peptide and brain natriuretic peptide were not different between the two treatments. However, plasma concentrations of active renin and norepinephrine were significantly higher with furosemide treatment than with azosemide treatment. QOL score was significantly lower with azosemide than with furosemide. These findings suggest that long-acting loop diuretics may have fewer adverse effects on the neuroendocrine system and QOL than short-acting loop diuretics in patients with mild CHF.

Administration, Oral↗
PubMed2001

Reduction of cardiac norepinephrine improves postischemic heart function in stroke-prone spontaneously hypertensive rats.

Although mammalian ventricle is richly supplied with adrenergic nerves, endogenous norepinephrine is not essential to the intrinsic contractility of the normal heart. However, it is not clear whether acute changes in cardiac norepinephrine could alter heart function in genetically hypertensive rats. The purpose of this study was to examine the effect of cardiac norepinephrine reduction on basal and postischemic heart function in stroke-prone spontaneously hypertensive rats (SHRSPs) using an isolated working heart preparation. Hypertrophied hearts of SHRSPs showed higher cardiac norepinephrine content and impaired heart function at 4 months of age as compared with normal Wistar-Kyoto rats. Poor postischemic recovery of heart function observed in SHRSPs was accompanied by large amounts of coronary norepinephrine overflow. Cardiac norepinephrine reduction or depletion did not affect basal heart function in SHRSPs. Considerable reduction in cardiac norepinephrine with acute reserpine injection (5 mg/kg) in SHRSPs significantly improved postischemic recovery of cardiac output, coronary flow, and rate-pressure product. However, complete norepinephrine depletion with reserpine (10 mg/kg) was detrimental to myocardial automaticity and limited the postischemic recovery of systolic function in the hypertrophied hearts. These results suggest that acute reduction in cardiac norepinephrine may be of potential therapeutic importance to postischemic dysfunction in the hypertrophied hearts.

Animals↗
PubMed2001

Cross-linking of beta2 integrins caused diminished responses of neutrophils to priming agents like lipopolysaccharide or tumor necrosis factor-alpha: possible involvement of tyrosine kinase Syk.

Neutrophils up-regulate beta2 integrins like CD11b/CD18 in response to lipopolysaccharide (LPS). Up-regulation of beta2 integrins causes neutrophils to adhere to surfaces, and to release superoxide anion (O2-). When neutrophils are exposed to LPS plus plasma under conditions not favorable for adherence (absence of Mg2+), the cells do not spontaneously release O2-, but instead they are primed for enhanced release of O2- after subsequent triggering by fMLP. In the presence of Mg2+, neutrophils adhere in response to LPS but fMLP-triggered O2- release by LPS-primed neutrophils is diminished. To understand why adherence interferes with the response of neutrophils to N-formyl-methionyl-leucyl-phenylalanine (fMLP), beta2 integrins were cross-linked by mouse monoclonal antibodies that had been immobilized by surface-bound anti-mouse antibody. When unprimed neutrophils were trapped on the surface by these cross-linked monoclonal antibodies, O2- release was triggered, and priming by LPS for fMLP-triggered O2- release was diminished, indicating that this cross-linking of beta2 integrins mimicked adherence. Alkaline phosphatase is up-regulated by LPS or tumor necrosis factor-alpha, and this response was also diminished by the cross-linking antibodies. The diminished alkaline phosphatase up-regulation was reversed by genistein, a general inhibitor of tyrosine kinases, and by piceatannol, an inhibitor for Syk kinase. Piceatannol also inhibited the phosphorylation of Syk caused by cross-linking of beta2 integrins. These results suggested that adherence-induced triggering and Syk kinase activation might be responsible for the diminished response of LPS-primed neutrophils to fMLP when neutrophils were adherent.

Alkaline Phosphatase↗
PubMed2001

Rapid detection of chromosome aneuploidies by prenatal interphase FISH (fluorescence in situ hybridization) and its clinical utility in Japan.

OBJECTIVE: The purpose of this study was to assess the accuracy, informative rate, detection rate, and clinical utility of prenatal interphase fluorescence in situ hybridization (FISH) analysis of amniotic fluid samples from Japanese women. METHODS: Amniotic fluid specimens from 2,639 Japanese women were received for prenatal interphase FISH and chromosome analysis. A questionnaire was designed to evaluate FISH clinical utility by collaboration sites. RESULTS: Based on 2,319 tested samples, the accuracy (100%), informative (94%), and detection (87.6%) rates were all high. The accuracy (100%), informative (90.2%), and detection (90.0%) rates were also remarkable in third-trimester pregnancies. We perceive significant advantages from this test regarding medical management and patient satisfaction. CONCLUSIONS: This novel report shows that in Japan prenatal interphase FISH testing is highly informative and accurate, not only in second-trimester pregnancies but also in third-trimester pregnancies. This test provides advantages to both physicians and patients, provided that its capabilities and limitations are understood.

Adult↗
PubMed2001

[Acute exacerbations due to Streptococcus pneumoniae in chronic lower respiratory tract infections during long-term macrolide therapy].

In Japan, long-term 14-membered macrolide administration is chosen as a first line therapy against chronic lower respiratory tract infections (CLRTIs) such as diffuse panbronchiolitis, bronchiectasis and chronic bronchitis. However, sometimes acute exacerbations occur in these cases, even if therapy is effective. We investigated 18 episodes of CLRTIs exacerbations that were caused by Streptococcus pneumoniae during long-term macrolides therapy from 1991 to 1999 to clarify the clinical features and prevalence of antimicrobial resistance in S. pneumoniae. Exacerbations did not occur only in winter season, but also in other seasons. Among 18 episodes of exacerbation, only 7 episodes (39%) revealed infiltration in chest roentogenogram and few episodes revealed marked elevations of inflammation markers in laboratory data. Intermediate resistance or resistance rates of S. pneumoniae isolated from sputum or transtracheal aspiration were 100% to erythromycin, 67% to clindamycin or minocycline, 11% to ampicillin, and 0% to cephazoline or imipenem. Coresistance to erythromycin, clindamycin and minocycline was seen in a half of the episodes. Resistance was not correlated with the duration of macrolides administration. All episodes were mainly treated with beta-lactam agents or fluoroquinolones and cured successfully. These findings suggest that acute exacerbations in CLRTIs caused by S. pneumoniae during long-term macrolides therapy do not reveal severe clinical aspects and can be treated successfully at present, but attention should be paid to the trend of antibiotic susceptibility in S. pneumoniae.

Adolescent↗
PubMed2001

[Pathogenetic study on bronchopulmonary infections in 1,416 patients by transtracheal aspiration method].

We have performed transtracheal aspiration (TTA) in 1,416 patients, who were suspected to have bronchopulmonary infection, in order to collect non-contaminated specimens directly from the lower airway. The overall isolation rates in 1,416 TTA were 68.7% for any microorganisms. Aerobes had a high incidence but many kinds of microorganisms were associated with bronchopulmonary infections. Haemophilus influenzae was the major pathogen in patients with acute bronchitis. Streptococcus pneumoniae was the most important pathogen and mycoplasma was often isolated in patients with community-acquired pneumonia. Major pathogens of nosocomial pneumonia consisted of alpha-streptococcus spp., anaerobes and Pseudomonas aeruginosa. Anaerobes were isolated from transtracheal aspirates in 20 of 33 episodes of lung abscesses. H. influenzae and P. aeruginosa were the main persistent pathogens and H. influenzae, S. pneumoniae and anaerobes were important exacerbated pathogens in patients with chronic lower respiratory tract infection. S. pneumoniae was isolated more from TTA than expectorated sputa. Oropharyngeal flora bacteria were easily isolated in the culture of expectorated sputa. We assessed the final diagnosis or causative factor in 443 patients whom no microorganism was isolated from transtracheal aspirates. The final diagnosis was infectious diseases in 52 patients (11.7%) and non-infectious diseases in 80 patients (18.1%), respectively. The causative factor was unsuited TTA sample in 81 patients (18.3%), preceding antimicrobial chemotherapy in 95 patients (21.4%) and unknown in 135 patients (30.5%), respectively. The pathogenesis of bronchopulmonary infections is complex and various microorganisms are associated with pathogens of bronchopulmonary infections. Therefore, we should accurately diagnose the pathogens in patients with bronchopulmonary infections. TTA is one of the useful methods that we can accurately detect the respiratory pathogens.

Adolescent↗
PubMed2001

Genetic characterization and evolutionary implications of a car gene cluster in the carbazole degrader Pseudomonas sp. strain CA10.

The nucleotide sequences of the 27,939-bp-long upstream and 9,448-bp-long downstream regions of the carAaAaBaBbCAc(ORF7)Ad genes of carbazole-degrading Pseudomonas sp. strain CA10 were determined. Thirty-two open reading frames (ORFs) were identified, and the car gene cluster was consequently revealed to consist of 10 genes (carAaAaBaBbCAcAdDFE) encoding the enzymes for the three-step conversion of carbazole to anthranilate and the degradation of 2-hydroxypenta-2,4-dienoate. The high identities (68 to 83%) with the enzymes involved in 3-(3-hydroxyphenyl)propionic acid degradation were observed only for CarFE. This observation, together with the fact that two ORFs are inserted between carD and carFE, makes it quite likely that the carFE genes were recruited from another locus. In the 21-kb region upstream from carAa, aromatic-ring-hydroxylating dioxygenase genes (ORF26, ORF27, and ORF28) were found. Inductive expression in carbazole-grown cells and the results of homology searching indicate that these genes encode the anthranilate 1,2-dioxygenase involved in carbazole degradation. Therefore, these ORFs were designated antABC. Four homologous insertion sequences, IS5car1 to IS5car4, were identified in the neighboring regions of car and ant genes. IS5car2 and IS5car3 constituted the putative composite transposon containing antABC. One-ended transposition of IS5car2 together with the 5' portion of antA into the region immediately upstream of carAa had resulted in the formation of IS5car1 and ORF9. In addition to the insertion sequence-dependent recombination, gene duplications and presumed gene fusion were observed. In conclusion, through the above gene rearrangement, the novel genetic structure of the car gene cluster has been constructed. In addition, it was also revealed that the car and ant gene clusters are located on the megaplasmid pCAR1.

Amino Acid Sequence↗
PubMed2001

CD31 expression on leukocytes is downregulated in vivo during hemodialysis.

BACKGROUND/AIM: CD31 on leukocytes is the adhesion molecule involved in the leukocyte extravasation in inflammatory conditions. During hemodialysis with cellulosic membranes, it is considered that activated leukocytes adhere to endothelium, but do not show extravasation. However, it is not elucidated why activated leukocytes do not show endothelial transmigration during hemodialysis with cellulosic membranes. METHODS: In the present study, changes in the expressions of Mac-1 and CD31 on granulocytes and monocytes were analyzed by flow cytometry during hemodialysis in 7 patients treated with regenerated-cellulose (RC) membranes and next with polysulfone (PS) membranes. RESULTS: During dialysis with RC, Mac-1 expressions on granulocytes and monocytes both significantly increased as compared with predialysis values and across the dialyzer. During dialysis with RC, the CD31 expression on granulocytes and monocytes significantly decreased as compared with predialysis values. During dialysis with PS, changes in Mac-1 and CD31 expressions on granulocytes and monocytes were smaller than those during dialysis with RC. CONCLUSIONS: Decreased CD31 expression on leukocytes may affect leukocyte function more in patients chronically hemodialyzed with RC than in those hemodialyzed with PS, since CD31 is important in leukocyte transendothelial migration in inflammatory conditions.

Adult↗