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Biomedical subjects

A Honda

Publications and source records attributed to A Honda.

At least 37 records · Page 2Linked to original sources
PubMed2001

Spatiotemporal dynamics of guanosine 3',5'-cyclic monophosphate revealed by a genetically encoded, fluorescent indicator.

To investigate the dynamics of guanosine 3',5'-cyclic monophosphate (cGMP) in single living cells, we constructed genetically encoded, fluorescent cGMP indicators by bracketing cGMP-dependent protein kinase (cGPK), minus residues 1-77, between cyan and yellow mutants of green fluorescent protein. cGMP decreased fluorescence resonance energy transfer (FRET) and increased the ratio of cyan to yellow emissions by up to 1.5-fold with apparent dissociation constants of approximately 2 microM and >100:1 selectivity for cGMP over cAMP. To eliminate constitutive kinase activity, Thr(516) of cGPK was mutated to Ala. Emission ratio imaging of the indicators transfected into rat fetal lung fibroblast (RFL)-6 showed cGMP transients resulting from activation of soluble and particulate guanylyl cyclase, respectively, by nitric oxide (NO) and C-type natriuretic peptide (CNP). Whereas all naive cells tested responded to CNP, only 68% responded to NO. Both sets of signals showed large and variable (0.5-4 min) latencies. The phosphodiesterase (PDE) inhibitor 3-isobutyl-1-methylxanthine (IBMX) did not elevate cGMP on its own but consistently amplified responses to NO or CNP, suggesting that basal activity of guanylate cyclase is very low and emphasizing the importance of PDEs in cGMP recycling. A fraction of RFL cells showed slowly propagating tides of cGMP spreading across the cell in response to delocalized application of NO. Biolistically transfected Purkinje neurons showed cGMP responses to parallel fiber activity and NO donors, confirming that single-cell increases in cGMP occur under conditions appropriate to cause synaptic plasticity.

Amino Acid Sequence↗
PubMed2001

Polymorphonuclear leukocyte adhesion to articular cartilage is inhibited by cartilage surface macromolecules.

The present studies deal with polymorphonuclear neutrophil (PMN) adhesion inhibitory properties of cartilage surface proteoglycans. Normal human PMN were used in adhesion experiments with bovine cartilage surfaces exposed to neutrophil elastase and reconstituted with fibronectin (Fn) or on plastic-bound Fn. An extract of cartilage surface small proteoglycans (SE) and purified fibromodulin (FM), decorin (DCN), biglycan (BGN), and aggrecan (AGN) on the surface of normal cartilage were used to test for inhibition of Fn-dependent cell adhesion. The PMN did not adhere to intact articular cartilage surfaces, whereas significant adhesion was measured using cartilage explants digested with elastase and reconstituted with Fn. Incubation of elastase-treated, Fn-reconstituted cartilage with 45 microg/ml SE inhibited PMN adhesion by 50.7 +/- 5.8% (P < 0.0001). Addition of 50 microg/ml purified FM to the reconstituted articular surfaces inhibited cell adhesion by 71.2 +/- 13.9% (P < 0.0001). Inhibition of PMN adhesion to plastic-bound Fn was seen with 1.7 microg/ml SE (20.4 +/- 8.0%). Maximal inhibition of 67.4 +/- 14.8% (P < 0.01) was obtained with 17.0 microg/ml SE. With FM, concentrations of 4.3 microg/ml resulted in 34.7 25.2 inhibition (P < 0.001), and maximal inhibition of 66.3 16.2% (P < 0.01) was obtained with 43.0 microg/ml. Similar results were obtained with purified bovine DCN and BGN. The main component of cartilage matrix, AGN, failed to inhibit cell adhesion significantly. The results indicate that macromolecules normally present on articular cartilage surfaces act as a barrier to PMN adhesion. Since cartilage surface proteins are susceptible to breakdown by proteases from synovial fluid inflammatory cells, we postulate that the degradation of this barrier may be responsible for increasing PMN adhesion and subsequent cartilage damage in inflammatory arthritis.

Aggrecans↗
PubMed2001

Assessment of tear concentrations on therapeutic drug monitoring. II. Pharmacokinetic analysis of valproic acid in guinea pig serum, cerebrospinal fluid, and tears.

PURPOSE: To quantitatively describe the pharmacokinetics of valproic acid (VPA) in guinea pig serum (total [Cf+b] and free [Cf]), cerebrospinal fluid (CSF) [C]CSF and tears [C]T using a simple kinetic model, and to examine whether [Cf] and [C]CSF can be predicted by [C]T using the resulting pharmacokinetic parameters. METHODS: [Cf+b], [Cf], [C]CSF and [C]T were determined after bolus i.v. injection of 10 or 20 mg/kg VPA using GC/ECNCI/MS. RESULTS: [Cf+b] could be quantitatively described by a two compartment model with linear elimination kinetics. [Cf] was separately analyzed using multi-exponential equations. [C]CSF was analyzed using a simple kinetic model in which the CSF compartment is independently connected with the serum compartment by the apparent diffusion constants (KINCSF and KOUTCSF). [C]T was analyzed using the same simple kinetic model used for [C]CSF. The values of [C]CSF and [Cf] in the steady state can be represented by the following equations; [C]CSF = KINCSF/KOUTCSF x [Cf], [Cf] = KOUT/KINT x [C]T, and indicating that [Cf] and [C]CSF can be predicted by [C]T using the resulting pharmacokinetic parameters. CONCLUSIONS: The measurement of [C]T which can be collected non-invasively and estimated the pharmacokinetic parameters for [Cf], [C]CSF, and [C]T might be a very useful method for TDM of VPA.

Animals↗
PubMed2001

[Clinical study of 33 children with systemic pneumococcal infections].

We retrospectively analyzed 33 cases of children with systemic pneumococcal infections, 22 bacteremia and 11 meningitis, diagnosed and treated in Asahi General Hospital between 1985 and 1999. The median age at diagnosis was 15 months old and the incidence peaked in infants between 7 and 24 months of age (57.6%). Two cases showed low serum IgG2 levels. Fever was a common symptom in all cases and 13 (39.4%) presented convulsions. Meningitis [median age: 10 months] tended to occur, if not significant, in younger children than bacteremia [16 months]. All cases of meningitis were diagnosed 12 hours or later after the onset of fever, though 54.5% of the cases of bacteremia were diagnosed within 12 hours. The cases of meningitis showed statistically lower white blood cell counts [median: 9,700/mm3] and higher CRP levels [median: 25.6 mg/dl] than those of bacteremia [23,900/mm3 and 4.2 mg/dl, respectively] at diagnosis. Although all cases of bacteremia were cured without any sequelae by antibiotic treatment, 3 cases (27.3%) of meningitis died and 4 (36.4%) developed severe neurological sequelae. Our findings suggest that the putative pathogenesis by which pneumococcal meningitis results from bacteremia and, taking in the account of the poor outcome of meningitis, may justify the early antibiotic intervention against pneumococcal bacteremia.

Bacteremia↗
PubMed2001

Suppression of collagen-induced arthritis in DBA/1J mice by preimmunization with house dust mite extract.

Collagen-induced arthritis (CIA) can be induced in DBA/1J mice by immunization with bovine type II collagen (bCII) and is a model of some types of human autoimmune rheumatoid arthritis. In this study we examined whether preimmunization of the mice with various antigens could inhibit the development of CIA. Preimmunization of the mice with an extract of the house dust mite Dermatophagoides farinae (mite antigen), chicken ovalbumin, or keyhole limpet hemocyanin strongly inhibited CIA development, but hen egg lysozyme, beta-lactoglobulin from bovine milk or myelin basic protein from guinea pig brain did not substantially affect CIA development. Splenic T cells and serum antibodies specific for mite antigen did not cross-react with bCII. Preimmunization of the mice with mite antigen did not affect the IFN-gamma and proliferative response of splenic T cells to bCII, nor serum antibody responses. The most inhibitory constituent had a molecular weight between 1,000 and 10,000.

Animals↗
PubMed2001

Effect of high-impact and low-repetition training on bones in ovariectomized rats.

This study was designed to investigate the effect of high-impact and low-repetition jump training on bones in ovariectomized (OVX) rats. Forty female Wistar rats were sham-operated (sham) or OVX at the age of 11 weeks. The rats were divided randomly into the following four groups: sham-sedentary (SS; n = 10), sham-exercised (SE; n = 10), OVX-sedentary (OS; n = 10), and OVX-exercised (OE; n = 10). The rats started the jump training at the age of 12 weeks. The jump-training protocol was 10 times/day, 5 days/week and the jumping-height was 40 cm. After 8 weeks of training, the mass and breaking force in the tibia and ulna, cross-sectional areas of diaphysis in the tibia, and serum bone turnover markers were measured. The jump training significantly increased the fat-free dry weight, ash weight, and ultimate breaking force in the tibia. The rate of increase in these parameters was similar in both the sham and the OVX groups. On the other hand, in the ulna, there were no significant changes in the ultimate breaking force. The jump training significantly increased the periosteal perimeter and cortical area, although the increase in these parameters in OE compared with OS was lower than that in SE compared with SS. The jump training significantly increased serum osteocalcin in the OVX groups, as well as in the sham groups. These results suggest that high-impact and low-repetition training had beneficial effects on bone formation and bone biomechanical properties in OVX rats, as well as in sham rats.

Animals↗
PubMed2001

Differences in hepatic levels of intermediates in bile acid biosynthesis between Cyp27(-/-) mice and CTX.

Cerebrotendinous xanthomatosis (CTX) is a rare, recessively inherited lipid storage disease characterized by a markedly reduced production of chenodeoxycholic acid and an increased formation of 25-hydroxylated bile alcohols and cholestanol. Patients with this disease are known to have mutations in the sterol 27-hydroxylase (Cyp27) gene. However, one study showed that mice with a disrupted Cyp27 gene did not have any CTX-related clinical or biochemical abnormalities. To explore the reason, hepatic cholesterol, cholestanol, and 12 intermediates in bile acid biosynthetic pathways were quantified in 10 Cyp27(-/-) and 7 Cyp27(+/+) mice, two CTX patients (untreated and treated with chenodeoxycholic acid), and four human control subjects by high resolution gas chromatography-mass spectrometry. Mitochondrial 27-hydroxycholesterol and 5beta-cholestane-3alpha,7alpha,12alpha,27-tetrol were virtually absent in both Cyp27(-/-) mice and CTX patients. In Cyp27(-/-) mice, microsomal concentrations of intermediates in the early bile acid biosynthetic pathway (7alpha-hydroxycholesterol, 7alpha-hydroxy-4-cholesten-3-one, 7alpha,12alpha-dihydroxy-4-cholesten-3-one, and 5beta-cholestane-3alpha,7alpha,12alpha-triol), 25-hydroxylated bile alcohols (5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol, 5beta-cholestane-3alpha,7alpha,12alpha,23R,25-pentol, and 5beta-cholestane-3alpha,7alpha,12alpha,24R, 25-pentol), and cholestanol were all significantly elevated compared with those in Cyp27(+/+) mice, although the levels were lower than those in untreated CTX patients. The intermediate levels in early bile acid biosynthesis were more elevated in male (16;-86% of CTX) than in female Cyp27(-/-) mice (7-30% of CTX). In contrast, 25-hydroxylated bile alcohol concentrations were not significantly different between male and female Cyp27(-/-) mice and were considerably lower (less than 14%) than those in CTX patients.These results suggest that 1) in Cyp27(-/-) mice, especially in females, classic bile acid biosynthesis via 7alpha-hydroxycholesterol is not stimulated as much as in CTX patients; and 2) formed 25-hydroxylated bile alcohols are more efficiently metabolized in Cyp27(-/-) mice than in CTX patients.

Adult↗
PubMed2001

[A case of right pneumonectomy and omentopexy for lung cancer after preoperative irradiation].

A 72-year-old man complaining of cough rejected the operation for squamous cell carcinoma obstructing the right intermediate trunk, therefore he was received 82 Gy (40 Gy and 42 Gy) of radiotherapy. However, the tumor did not decrease, in addition, cough and purulent sputum became severe gradually. We performed right pneumonectomy and omentopexy to prevent bronchial fistula, he had no pulmonary complication. Radiotherapy is a risk factor for postoperative bronchial fistula, omentopexy is useful to prevent it.

Aged↗
PubMed2001

[A study on contamination from Legionella spp. at a home for the elderly in Toyohashi City].

OBJECTIVE: Legionnaires disease has been attributed to Legionella spp. in the water distribution systems of buildings. However, recently cases due to contamination of thermal-bath water have been reported in Japan. In this investigation, we examined the supervision of baths and the presence of Legionella spp. in thermal-bath water of homes for the elderly in Toyohashi city. METHODS: The research was conducted through questionnaires on bathing facilities at 50 sites. Thermal baths were found to be installed at 14 of the sites. We then tested 22 samples from the 14 sites for Legionella spp. and other materials. RESULTS: From the genus Legionella, only Legionella pneumophila was detected, in 8 samples from 4 sites. Coliforms were also detected. Moreover, disinfectant was not detected in any of the Legionella positive samples of bath water. Legionella positive sites had, however, been replacing their water once a day. CONCLUSIONS: These findings indicate that the use of disinfectant and the proper supervision of bathing facilities are important in controlling Legionella spp. Legionnaires disease can be averted in homes for the elderly through appropriate measures.

Aged↗
PubMed2000

Novel and recurrent EBP mutations in X-linked dominant chondrodysplasia punctata.

Chondrodysplasia punctata (CDP) is a heterogeneous group of skeletal dysplasias characterized by stippled epiphyses. A subtype of CDP, X-linked dominant chondrodysplasia punctata (CDPX2), known also as Conradi-Hünermann-Happle syndrome, is a rare skeletal dysplasia characterized by short stature, craniofacial defects, cataracts, ichthyosis, coarse hair, and alopecia. The cause of CDPX2 was unknown until recent identification of mutations in the gene encoding Delta(8),Delta(7) sterol isomerase emopamil-binding protein (EBP). Twelve different EBP mutations have been reported in 14 patients with CDPX2 or unclassified CDP, but with no evidence of correlation between phenotype and nature of the mutation. To characterize additional mutations and investigate possible phenotype-genotype correlation, we sequenced the entire EBP gene in 8 Japanese individuals with CDP; 5 of them presented with a CDPX2 phenotypes. We found EBP mutations in all 5 CDPX2 individuals, but none in non-CDPX2 individuals. Three of these CDPX2 individuals carried novel nonsense mutations in EBPand the other two, separate missense mutations that had been reported also in different ethnic groups. Our results, combined with previous information, suggest all EBP mutations that produce truncated proteins result in typical CDPX2, whereas the phenotypes resulted from missense mutations are not always typical for CDPX2. Patients with nonsense mutations showed abnormal sterol profiles consistent with a defect in Delta(8), Delta(7) sterol isomerase. X-inactivation patterns of the patients showed no skewing, an observation that supports the assumption that inactivation of the EBP gene occurs at random in affected individuals.

Adolescent↗
PubMed2000

Detection of mutations in hepatitis B virus enhancer 2/core promoter and X protein regions in patients with fatal hepatitis B virus infection.

The enhancer 2/core promoter and the X protein regions located upstream of the precore and core regions in hepatitis B virus regulate expression of core/e antigen peptides. Mutations in the precore and core regions have been reported to be associated closely with the severity of type B hepatitis, and regions regulating expression of these peptides may also be involved in severe liver damage. Mutations were examined in regions that may be related to fatal liver diseases. Nucleotide sequences and deduced amino acid sequences from 20 patients with fatal type B hepatitis (12 with fulminant hepatitis and 8 with severe exacerbation) and 10 patients with self-limited acute hepatitis were analyzed. There were 50 nucleotide alterations in the enhancer 2/core promoter region of virus from 12 patients with fulminant hepatitis (average 4.1/case), 37 alterations in 8 patients with severe exacerbation (4.6/case), and 10 mutations in 10 cases of acute hepatitis (1.0/case). The numbers of amino acid mutations in X protein were 53 in 12 cases of fulminant hepatitis (4.4/case), 27 in 8 cases of severe exacerbation (3.3/case), and 9 in 10 cases of acute hepatitis (0.9/case). In fatal cases, approximately 50% of the nucleotide mutations were located within the region spanning nucleotides 1741-1777 (14.2% of the enhancer 2/core promoter region) and 30% of the amino acid mutations in X protein were located within the region containing codons 122-132 (7.1% of X protein). In addition to mutations in the precore and core regions, mutations in the enhancer 2/core promoter and the X protein regions may be associated with the pathogenesis of fatal B hepatitis infection.

Adult↗
PubMed2000

Effects of pregnancy and lactation on trabecular bone and marrow adipocytes in rats.

Changes in the structure and metabolism of trabecular bone and marrow adipocytes in rats during pregnancy and the early stage of postpartum were evaluated by investigating bone mineral density (BMD) and bone and fat histomorphometry. Forty-nine female virgin Sprague-Dawley rats aged 200 days were mated and divided into seven groups: (1) beginning controls; (2) antepartum-on-day-7; (3) antepartum-on-day-21; (4) nonlactating on the fourth postpartum day; (5) nonlactating on the sixth postpartum day; (6) nonlactating on the eighth postpartum day; (7) lactating on the eight postpartum day. The significant decreases occurred in the trabecular bone at the end of pregnancy and lactation, and the bone formation increases and the bone structure is almost recovered in nonlactating rats within 6 days of postpartum. The percent adipocyte volume, adipocyte number, and unit adipocyte volume significantly decreased during postpartum whether lactating or nonlactating, and they significantly showed negative correlation with the osteoid volume values. The serum triglyceride value and body weight of the seven groups correlated significantly with the unit adipocyte volume value (r = 0.49, P = 0.004; r = 0.58, P = 0.0005, respectively). We concluded that bone resorption and formation are regulated separately during late pregnancy and lactation and that the recovery of BMD from lactation appears to rely on an acceleration of bone formation. Furthermore, the metabolism of the marrow adipocyte may be correlated with bone formation rates, serum triglyceride value, and body weight during pregnancy and early stage of puerperium.

Absorptiometry, Photon↗
PubMed2000

Involvement of muscarinic cholinergic and alpha2-adrenergic mechanisms in growth hormone secretion during exercise in humans.

The purpose of this study was to examine the role of muscarinic cholinergic and alpha2-adrenergic mechanisms in growth hormone (GH) secretion during exercise in humans. The GH responses induced during moderate-intensity exercise (using a cycle ergometer at 60% maximal oxygen uptake, VO2max, for 30 min) without treatment (control) and after the administration of a muscarinic cholinergic antagonist (atropine 1 mg) or after an alpha2-adrenergic antagonist (yohimbine 15 mg) were compared in seven healthy men. Although, serum GH concentration had increased significantly after exercise in the control experiment [mean peak GH concentration 52.64 (SEM 18.60) ng x ml(-1)], the increase was suppressed by the administration of either atropine [mean peak GH concentration 8.64 (SEM 7.47) ng x ml(-1)] or yohimbine [mean peak GH concentration 17.50 (SEM 7.89) ng x ml(-1)]. The area under the curve of serum GH concentration against time was significantly lower in the experiment using these drugs [with atropine, mean area 458 (SEM 409) ng x ml(-1) min], with yohimbine mean area 946 (SEM 435) ng x ml(-1) min] than in the control experiment [mean area 3135 (SEM 1098) ng x ml(-1) x min]. These results suggest that muscarinic cholinergic and alpha2-adrenergic mechanisms are involved in GH secretion during exercise in humans.

Adrenergic alpha-2 Receptor Antagonists↗
PubMed2000

Botryoid Wilms tumor: case report and review of literature.

A rare case of botryoid Wilms tumor is presented. The main clinical manifestations were persistent low-grade fever, malaise, and proteinuria associated with microhematuria. Ultrasonography revealed an echogenic mass in the right kidney, and a contrast-enhanced mass was found in the dilated collecting system by contrast-enhanced computed tomography. The surgically resected tumor was a polypoid, light-yellow, glistening mass that occupied a large part of the renal pelvis and originated from the pelvicaliceal wall. Part of the tumor extended to the proximal ureter, resulting in hydronephrosis in the involved kidney. No parenchymal lesion was observed. Microscopic examination revealed epithelial, stromal, and blastemal components, which indicated Wilms tumor. Infection had occurred in the hydronephrotic kidney, which presumably had caused the major presenting symptoms. The prognosis of our patient and previously reported cases of botryoid Wilms tumor was good compared with that of typical Wilms tumor, since the botryoid type can be detected at an early stage.

Hematuria↗
PubMed2000

HCV-core protein accelerates recovery from the insensitivity of liver cells to Fas-mediated apoptosis induced by an injection of anti-Fas antibody in mice.

BACKGROUND/AIMS: Hepatitis C virus (HCV) is a major etiologic agent of chronic hepatitis, cirrhosis, and hepatocellular carcinoma. The aim of this study was to elucidate pathological effects of HCV-core protein on liver cells. METHODS: We have generated transgenic mice carrying HCV-core cDNA (Px-core) and pathologically examined livers of Px-core mice. RESULTS: HCV-core protein was detectable in livers from lines 5 (C5) and 8 (C8) of Px-core transgenic mice. Since chronic hepatitis and cirrhosis precede hepatocellular carcinoma in patients with HCV infection, we tried to examine the effect of repetitive injection of a small dose of anti-Fas antibody in the transgenic mice. Surprisingly, an initial injection of anti-Fas antibody induced resistance of liver cells to the second injection of anti-Fas antibody in both Px-core and littermate control mice. The insensitivity of liver cells induced in the control mice continued for more than 24 weeks after the first injection but was broken within 1 week after partial hepatectomy. However, the sensitivity was restored in the Px-core mice within 12 weeks after the injection. CONCLUSION: HCV-core protein in liver cells may affect persistence of Fas-mediated liver cell injury.

Animals↗
PubMed2000

Regulation of cholesterol biosynthetic pathway in patients with the Smith-Lemli-Opitz syndrome.

The Smith-Lemli-Opitz syndrome (SLOS) is a recessively inherited birth disorder caused by a defect in 7-dehydrocholesterol (3beta-hydroxysteroid) delta7-reductase, the final enzyme in cholesterol biosynthesis. To investigate in vivo regulation of the cholesterol biosynthetic pathway in SLOS, we measured hepatic microsomal sterol concentrations and activities of several key enzymes in the pathway, including HMG-CoA synthase, HMG-CoA reductase, squalene synthase and 7-dehydrocholesterol delta7-reductase in liver specimens from a patient with SLOS and 11 controls. Hepatic microsomal 7-dehydrocholesterol delta7-reductase activity in the patient was less than 1% of the control mean, and decreased cholesterol concentration and markedly increased 7- and 8-dehydrocholesterol concentrations were observed in the patient's microsomes. HMG-CoA synthase and squalene synthase activities in the patient were upregulated to 149% and 532%, respectively, while the activity of HMG-CoA reductase, the rate-limiting enzyme in the pathway, was reduced to 39% of the control mean. Downregulation of HMG-CoA reductase activity in SLOS was supported by measuring plasma levels of mevalonic acid, the immediate product of HMG-CoA reductase. The levels in SLOS patients (n = 9) were significantly low compared with age-matched controls (n = 8) (12+/-2 vs 28 + 6nmol/L, p < 0.05). These results suggest that in most SLOS patients in vivo HMG-CoA reductase is not stimulated in spite of blocked cholesterol biosynthetic pathway and reduced plasma and hepatic cholesterol concentrations.

Case-Control Studies↗