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Biomedical subjects

M Adachi

Publications and source records attributed to M Adachi.

At least 127 records · Page 7Linked to original sources
PubMed2000

A conserved docking motif in MAP kinases common to substrates, activators and regulators.

Mitogen-activated protein kinases (MAPKs) are specifically phosphorylated and activated by the MAPK kinases, phosphorylate various targets such as MAPK-activated protein kinases and transcription factors, and are inactivated by specific phosphatases. Recently, docking interactions via the non-catalytic regions of MAPKs have been suggested to be important in regulating these reactions. Here we identify docking sites in MAPKs and in MAPK-interacting enzymes. A docking domain in extracellular-signal-regulated kinase (ERK), a MAPK, serves as a common site for binding to the MAPK kinase MEK1, the MAPK-activated protein kinase MNK1 and the MAPK phosphatase MKP3. Two aspartic acids in this domain are essential for docking, one of which is mutated in the sevenmaker mutant of Drosophila ERK/Rolled. A corresponding domain in the MAPKs p38 and JNK/SAPK also serves as a common docking site for their MEKs, MAPK-activated protein kinases and MKPs. These docking interactions increase the efficiency of the enzymatic reactions. These findings reveal a hitherto unidentified docking motif in MAPKs that is used in common for recognition of their activators, substrates and regulators.

Amino Acid Motifs↗
PubMed2000

Expression of vascular endothelial growth factor by synovial fluid neutrophils in rheumatoid arthritis (RA).

Most of the leucocytes infiltrating rheumatoid synovial fluid (SF) are neutrophils capable of producing a variety of inflammatory mediators known to contribute significantly to the disease process during active RA. In the present study, we investigated the contribution made by SF neutrophils to the elevated levels of vascular endothelial growth factor (VEGF) seen in rheumatoid SF. Rheumatoid SF neutrophils were found to contain significantly larger amounts of both VEGF protein and its mRNA than peripheral blood neutrophils from either RA patients or healthy controls. Levels of cell-associated VEGF were well correlated with free VEGF in SF, which was significantly higher than in SF from osteoarthritis patients. Levels of SF neutrophil-associated VEGF also correlated with RA disease activity and cell surface integrin expression. Thus, SF neutrophil-associated VEGF may be considered an indicator of both local and systemic inflammation of RA, contributing to the neovascularization seen during RA synovitis.

Arthritis, Rheumatoid↗
PubMed2000

Suppressive activity of a macrolide antibiotic, roxithromycin on co-stimulatory molecule expression on mouse splenocytes in vivo.

The influence of roxithromycin (RXM) on the expression of co-stimulatory molecules, CD40, CD80 and CD86, was examined in vivo. When BALB/c mice were immunized intraperitoneally with two doses of dinitrophenylated ovalbumin (DNP-OVA) at 1 week intervals, intraperitoneal administration of RXM at 250 microg/kg once a day for 14 days strongly suppressed IgE contents in sera obtained from mice 22 days after the first immunization. In addition, RXM treatment of mice suppressed endogenous IL-4 contents in aqueous spleen extracts, which were enhanced by DNP-OVA immunization. We next examined the influence of RXM on co-stimulatory molecule expression on splenic lymphocytes. RXM treatment of the immunized mice caused suppression of CD40 expression, but this treatment did not affect CD80 and CD86 expression.

Animals↗
PubMed2000

Paired-like homeodomain proteins Phox2a/Arix and Phox2b/NBPhox have similar genetic organization and independently regulate dopamine beta-hydroxylase gene transcription.

The homeodomain transcription factors Arix/Phox2a and NBPhox/Phox2b play a role in the specification of the noradrenergic phenotype of central and peripheral neurons. To better understand the functions of these two factors, we have compared the genetic organization, chromosomal location, and transcriptional regulatory properties of Arix and NBPhox. The gene structure is very similar, with each gene containing three exons and two introns, extending a total of approximately 5 kb. Arix and NBPhox are unlinked in human and mouse genomes. NBPhox is located on human Chromosome 4p12 and mouse Chromosome 5, while Arix is located on human Chromosome 11q13 and mouse Chromosome 7. Both proteins bind to three sites in the promoter proximal region of the rat dopamine beta-hydroxylase gene (DBH). In vitro, Arix and NBPhox form DNA-independent multimers and exhibit cooperative binding to the DB1 regulatory element, which contains two homeodomain recognition sites. Both proteins regulate transcription from the rat DBH promoter, and transcription is synergistically increased in the presence of the protein kinase A catalytic subunit (PKA) plus either Arix or NBPhox. The transcription factors exhibit similar concentration-dependent efficacies, and when they are coexpressed, transcription is stimulated to a value approximately equal to that seen with either factor alone. The N-terminal segment of Arix is essential for transcriptional regulatory activity, and this region bears 50% identity with NBPhox, suggesting a similar mechanism of transcriptional activation of the DBH gene. We conclude from this study that Arix and NBPhox exhibit indistinguishable and independent transcriptional regulatory properties on the DBH promoter.

Amino Acid Sequence↗
PubMed2000

Effect of outdoor and indoor nitrogen dioxide on respiratory symptoms in schoolchildren.

BACKGROUND: Nitrogen dioxide (NO(2)), an oxidant gas that contaminates both outdoor and indoor air, is considered to be a potential risk factor for asthma. We investigated concurrently the effects of outdoor and indoor NO(2) on the prevalence and incidence of respiratory symptoms among children. METHODS: A cohort study was carried out over 3 years on 842 schoolchildren living in seven different communities in Japan. Indoor NO(2) concentrations over 24 hours were measured in both winter and summer in the homes of the subjects, and a 3-year average of the outdoor NO(2) concentration was determined for each community. Respiratory symptoms were evaluated every year from responses to questionnaires. RESULTS: The prevalence of bronchitis, wheeze, and asthma significantly increased with increases of indoor NO(2) concentrations among girls, but not among boys. In neither boys nor girls were there significant differences in the prevalence of respiratory symptoms among urban, suburban, and rural districts. The incidence of asthma increased among children living in areas with high concentrations of outdoor NO(2). Multiple logistic regression analysis showed that a 10 parts per billion (ppb) increase of outdoor NO(2) concentration was associated with an increased incidence of wheeze and asthma (odds ratios [OR] = 1.76, 95% CI : 1.04-3.23 and OR = 2.10, 95% CI : 1.10-4.75, respectively), but that no such associations were found with indoor NO(2) concentration (OR = 0.73, 95% CI : 0.45-1.14 and OR = 0.87, 95% CI : 0.51-1.43, respectively). CONCLUSIONS: These findings suggest that outdoor NO(2) air pollution may be particularly important for the development of wheeze and asthma among children. Indoor NO(2) concentrations were associated with the prevalence of respiratory symptoms only among girls. Girls may be more susceptible to indoor air pollution than boys.

Air Pollutants↗
PubMed2000

Computed tomographic fluoroscopy-guided transthoracic needle biopsy for diagnosis of pulmonary nodules.

BACKGROUND: The purpose of this study was to evaluate the usefulness of computed tomographic (CT) fluoroscopy-guided transthoracic needle biopsy (TTNB) with an 18-gauge automatic biopsy gun for the diagnosis of pulmonary nodules. METHODS: Between March 1996 and January 1998, 50 patients in whom pulmonary lesions could not be diagnosed cytopathologically with fiberoptic bronchoscopy or were not clearly visualized with fluoroscopy underwent CT fluoroscopy-guided TTNB. RESULTS: Final pathological diagnoses were 23 lung carcinomas, five pulmonary metastases and 22 benign lesions. Sufficient tissue for analysis was obtained from 48 of the 50 lesions (96%). The overall diagnostic yield of CT fluoroscopy-guided TTNB was 90%. The sensitivity, specificity and accuracy for malignancy were 89%, 100% and 94%, respectively. In 20 of the 22 cases (91%) of benign lesions, histological analysis yielded correct and specific diagnoses. Complications occurred in 22 of the 50 cases (44%). The most common complication was pneumothorax, which occurred in 21 of the 50 cases (42%). Chest tube insertion was required in 6 (12%). CONCLUSIONS: Although CT fluoroscopy could not decrease the complication rate, CT fluoroscopy-guided TTNB with an automatic biopsy gun appears to be a promising technique for diagnosing pulmonary lesions, particularly benign lesions.

Adenocarcinoma↗
PubMed2000

Effect of turgor pressure on outer hair cell motility.

The motor in the outer hair cell converts electrical energy directly into mechanical energy. There are two possible mechanisms for such a motor: one depends on changes in the membrane area ("area motor") and the other on changes in the stiffness ("stiffness motor"). These two mechanisms, which are not mutually exclusive, give different predictions on turgor pressure dependence of the amplitude. It was found that an increased pressure shifts the voltage dependence but does not change the amplitude of length changes. This observation is incompatible with a pure stiffness motor model. It was also confirmed that length changes are closely related to charge movements by monitoring the membrane capacitance. It can be concluded that hair cell motility is primarily based on area changes, and not changes in the elastic moduli.

Animals↗
PubMed2000

Antibody to heat shock protein can be used for early serological monitoring of Helicobacter pylori eradication treatment.

Infection with Helicobacter pylori induces humoral immune responses against various antigens of the bacterium. Heat shock proteins (hsps) are immunodominant antigens in various diseases including H. pylori infection. In the present study, we measured the anti-hsp antibody titers in 42 patients with H. pylori-infected peptic ulcers during a bacterial eradication study. The patients were treated with a proton pump inhibitor and antimicrobial agents to eradicate the organism. Their sera were obtained at pretreatment and at 1 month and 6 months after the eradication therapy. The titers of immunoglobulin G antibodies to the H. pylori hsp, whole-cell lysate, and urease (30-kDa subunit) antigens in serum were measured by a capture enzyme-linked immunosorbent assay. The levels of H. pylori hsp60 antibodies in sera collected 1 month after treatment had declined significantly, even when changes in the titers of antibodies to whole-cell and urease antigens were not apparent. These results suggest that measurement of antibodies to H. pylori hsp60 in serum is useful for the early monitoring of the effectiveness of eradication therapy.

Adult↗
PubMed2000

Effects of fructose and glucose on plasma leptin, insulin, and insulin resistance in lean and VMH-lesioned obese rats.

To determine the influence of dietary fructose and glucose on circulating leptin levels in lean and obese rats, plasma leptin concentrations were measured in ventromedial hypothalamic (VMH)-lesioned obese and sham-operated lean rats fed either normal chow or fructose- or glucose-enriched diets (60% by calories) for 2 wk. Insulin resistance was evaluated by the steady-state plasma glucose method and intravenous glucose tolerance test. In lean rats, glucose-enriched diet significantly increased plasma leptin with enlarged parametrial fat pad, whereas neither leptin nor fat-pad weight was altered by fructose. Two weeks after the lesions, the rats fed normal chow had marked greater body weight gain, enlarged fat pads, and higher insulin and leptin compared with sham-operated rats. Despite a marked adiposity and hyperinsulinemia, insulin resistance was not increased in VMH-lesioned rats. Fructose brought about substantial insulin resistance and hyperinsulinemia in both lean and obese rats, whereas glucose led to rather enhanced insulin sensitivity. Leptin, body weight, and fat pad were not significantly altered by either fructose or glucose in the obese rats. These results suggest that dietary glucose stimulates leptin production by increasing adipose tissue or stimulating glucose metabolism in lean rats. Hyperleptinemia in VMH-lesioned rats is associated with both increased adiposity and hyperinsulinemia but not with insulin resistance. Dietary fructose does not alter leptin levels, although this sugar brings about hyperinsulinemia and insulin resistance, suggesting that hyperinsulinemia compensated for insulin resistance does not stimulate leptin production.

Animals↗
PubMed2000

Expression of eotaxin by normal airway epithelial cells after influenza virus A infection.

BACKGROUND: Viral infection is known to cause lung inflammatory disease, including bronchial asthma. The mechanisms of inflammatory cell accumulation into the airways after viral infection are not well understood. Eotaxin is a CC chemokine which is a potent and specific agonist for CC chemokine receptor 3 (CCR3). CCR3 is expressed on eosinophils, basophils and T lymphocytes. These cells are known to be key cells in the pathogenesis of asthma. Although it has recently been demonstrated that airway epithelial cells express eotaxin in vivo and in vitro, there are few data about its epxression in viral infection. We hypothesized that eotaxin may play an important role in attracting inflammatory cells to the airways after viral infection, and analyzed whether viral infection attracts eotaxin in bronchial epithelial cells in vitro. METHODS: Human airway epithelial cells obtained from bronchial tissue at lobectomy for lung cancer were infected with influenza virus A (subtype H3N2). The cells and cultured media were collected 8, 24, and 48 h after infection. Eotaxin mRNA was analyzed with reverse transcriptase-polymerase chain reaction. Eotaxin protein levels in the culture media were analyzed by enzyme-linked immunosorbent assay. We also studied a blocking assay to analyze the intervention of proinflammatory cytokines in its production induced by influenza virus. RESULTS: Eotaxin mRNA appeared to be expressed constitutively in uninfected cells but was expressed more clearly in infected cells. Eotaxin protein release into culture media significantly increased after infection. Anti-TNF-alpha and anti-IL-1beta antibodies did not alter the eotaxin protein levels after viral infection. CONCLUSIONS: These results suggest that influenza virus A infection in airway epithelial cells activates the expression of eotaxin and that eotaxin may participate in the pathogenesis of airway inflammatory disease caused by viral infection, such as infectious type asthma.

Bronchi↗
PubMed2000

Three novel PHEX gene mutations in Japanese patients with X-linked hypophosphatemic rickets.

X-linked hypophosphatemic rickets (XLH) is an X-linked dominant disorder characterized by renal phosphate wasting, abnormal vitamin D metabolism, and defects of bone mineralization. The phosphate-regulating gene on the X-chromosome (PHEX) that is defective in XLH has been cloned, and its location identified at Xp22.1. It has been recognized to be homologous to certain endopeptidases. So far, a variety of PHEX mutations have been identified mainly in European and North American patients with XLH. To analyze the molecular basis of four unrelated Japanese families with XLH, we determined the nucleotide sequence of the PHEX gene of affected members. We detected a new nonsense mutation (R198X) in exon 5, a new 3 nucleotides insertion mutation in exon 12 and a new missense mutation (L160R) in exon 5 as well as a previously reported nonsense mutation in exon 8 (R291X). These results suggest that: 1) PHEX gene mutations are responsible for XLH in Japanese patients, and 2) PHEX gene mutations are heterogeneous in the Japanese population similarly to other ethnic populations.

Adult↗
PubMed2000

A novel missense mutation of mineralocorticoid receptor gene in one Japanese family with a renal form of pseudohypoaldosteronism type 1.

Pseudohypoaldosteronism type 1 (PHA1) is a rare condition characterized by neonatal salt loss with dehydration, hypotension, hyperkalemia, and metabolic acidosis, despite elevated plasma aldosterone levels and PRA. Two modes of inheritance of PHA1 have been described: an autosomal dominant form and an autosomal recessive form. An autosomal recessive form manifests severe life-long salt wasting resulting from multiple mineralocorticoid target tissue such as sweat, salivary glands, the colonic epithelium, and lung. Contrary, an autosomal dominant PHA1 manifests milder salt wasting that gradually improves with advancing age. Recently, in one sporadic and four dominant cases, four different mutations including two frame shift mutations, two premature termination codons, and one splice site mutation in the mineralocorticoid receptor (MR) gene were identified. We studied the molecular mechanisms of one Japanese family with a renal form of PHA1. PCR and direct sequencing of the MR gene identified a heterozygous point mutation changing codon 924 Leu (CTG) to CCG (Pro) (L924P) in all affected members. COS-1 cells were transfected with expression vectors for either wild type or the mutant MR-L924P receptors, together with the reporter plasmid (glucocorticoid response element tk-CAT). Aldosterone increased CAT activity in cells expressing wild-type receptor, but had no effect in cells expressing the mutant receptors. These results suggest that mineralocorticoid resistance in this family is due to a missense mutation in the MR gene. To our knowledge, this is the first case of the missense mutation of the MR gene in renal PHA1.

Adolescent↗
PubMed2000

Scant parasitemia in BALB/c mice with congenital malaria infection.

Balb/c mice were examined to determine whether or not they transmitted rodent malaria, Plasmodium berghei, to their fetuses. On the 15th day of pregnancy, mice were inoculated with approximately 3 x 10(6) P. berghei-infected erythrocytes by peritoneal injection. The blood from 27 adult females and 196 neonates was examined using a sensitive polymerase chain reaction (PCR) method with a detection level of approximately 1 parasite/microl blood. The average parasitemia of females at delivery was 8.1%, ranging from nondetectable to 37.1%. In 12 females, nested PCR established the presence of blood parasite DNA. Malaria parasites were microscopically confirmed in 2 of the 12 neonates. Maternal parasitemia at the time of delivery was not correlated with the incidence of vertical infection (6.1%), which was higher in this study than that found in previous studies. Although the combination of balb/c mice and P. berghei has not been used to examine vertical transmission of malaria, our report showed that this model may be used for this purpose.

Animals↗
PubMed2000

Genetic analysis of Japanese patients with persistent hyperinsulinemic hypoglycemia of infancy: nucleotide-binding fold-2 mutation impairs cooperative binding of adenine nucleotides to sulfonylurea receptor 1.

To elucidate the genetic etiology of persistent hyperinsulinemic hypoglycemia of infancy (PHHI) in the Japanese population, we conducted a polymerase chain reaction-single-strand conformation polymorphism analysis of the sulfonylurea receptor 1 (SUR1) and Kir6.2 genes in 17 Japanese PHHI patients, including a pair of siblings from a consanguineous family. We also analyzed the glutamate dehydrogenase gene for the exons encoding an allosteric regulatory domain of the enzyme. In the SUR1 gene, we identified one frameshift (I446fsdelT) and two missense (R1420C, R1436Q) mutations. None of these mutations were found in control Japanese subjects. Siblings homozygous for the R1420C mutation had a mild form, whereas two patients heterozygous for the I446fsdelT and R1436Q mutations, respectively, exhibited a severe form of PHHI. Functional consequences of these mutations on K(ATP) function were evaluated using 86Rb+ efflux studies in COS-7 cells. SUR1-446fsdelT and SUR1-1436Q did not form a functional K(ATP). Western blot analysis after transient expression in COS-7 cells revealed the expression of SUR1-1436Q protein to be markedly reduced, suggesting SUR1-1436Q to be unstable in these cells. K(ATP)(SUR1-1420C) showed reduced responses to metabolic inhibition by oligomycin and 2-deoxyglucose. K(ATP) channels are under complex regulation by intracellular ATP and ADP. ATP both inhibits and activates these channels. The inhibition is probably mediated through direct ATP interaction with a pore-forming subunit Kir6.2, whereas the activation is likely to be through a regulatory subunit SUR1. There is a cooperative regulation of ATP and ADP binding to SUR1, and this cooperativity may be involved in regulating the K(ATP) channel. In SUR1-1420C, high-affinity binding of ATP to the nucleotide-binding fold (NBF)-1 was indistinguishable from that of wild-type SUR1. However, stabilization of ATP binding to NBF-1 by MgATP or MgADP was impaired, suggesting that this defect may account for impaired K(ATP)(SUR1-1420C) function. This is the first direct biochemical evidence that the cooperativity of nucleotide binding to SUR1 is impaired in a SUR1 mutant causing PHHI. No mutations were identified in the Kir6.2 and glutamate dehydrogenase genes. The genetic etiology of PHHI appears to be heterogeneous. SUR1 mutations may account for no more than 20% of PHHI cases in Japanese patients. Mutations of Kir6.2 and glutamate dehydrogenase genes are likely to be even less common.

ATP-Binding Cassette Transporters↗
PubMed2000

The K-ras gene regulates vascular endothelial growth factor gene expression in non-small cell lung cancers.

Tumor angiogenesis is an essential step for tumor cell growth, progression and metastasis. Vascular endothelial growth factor (VEGF) is mitogen specific for endothelial cells, and therefore is believed to play a key role in tumor angiogenesis. However, the mechanisms underlying the regulation of VEGF expression remain virtually unknown and the only major regulator of VEGF expression has been reported to be hypoxia. Recently, it was reported that a mutant p53 in#duced the expression of VEGF mRNA, and that wild-type p53 down-regulated endogenous VEGF mRNA levels. In contrast, it has also been reported that mutant ras oncogenes were associated with the marked up-regulation of VEGF in transformed epithelial cells. Based on these results, we performed a retrospective study of the p53 and K-ras genes status and VEGF gene expression in the tumor tissues from 181 patients with non-small cell lung cancer using SSCP, sequencing, RT-PCR and immunohistochemical techniques. Forty-six carcinomas (25.4%) were evaluated as having high VEGF expression, and 135 tumors (74.6%) had low VEGF expression. Of the 181 primary NSCLC studied, 63 carcinomas (34.8%) contained mutations of p53, whereas only 14 carcinomas (7.7%) had mutations of K-ras. There were no significant relationships between VEGF expression and p53 status or each mutant exon of p53. In contrast, a significant difference was found between VEGF expression and K-ras status. Of the 14 tumors with mutant K-ras genes, 7 cases (50.0%) had high VEGF expression whereas only 39 of the 167 tumors with wild-type K-ras (23.4%) had high VEGF expression (p=0.0278). The mean VEGF conservation rate for the 14 tumors with mutant K-ras genes was 0.77+/-0.58 and the rate of the 167 tumors with wild-type K-ras genes was 0.49+/-0.46 (p=0. 0350). Moreover, the overall survival rate of patients with high VEGF expression was lower than patients with low VEGF expression (45.7% vs 60.7%, p=0.0419). On the other hand, there was no significant difference in the overall survival rate between patients with a mutant p53 and those with a wild-type p53; there was also no difference in the overall survival between patients with a mutant K-ras and those with a wild-type K-ras. The Cox regression model analysis indicated that three variables, VEGF status, K-ras status and nodal status, were found to be significant indicators for prognosis (p=0.0236, p=0.0172 and p<0.0001, respectively). Our data suggest that a high expression of VEGF in lung cancer may be associated with a poor prognosis. This may be a clue to improving lung cancer diagnoses and therapies aimed at inhibiting tumor angiogenesis due to VEGF.

Adult↗
PubMed2000

Significance of integrin alpha5 gene expression as a prognostic factor in node-negative non-small cell lung cancer.

The integrin family plays a major role in complex biological events such as differentiation, development, wound healing, and the altered adhesive and invasive properties of tumor cells. Integrin (alpha5beta1 is a classical fibronectin receptor, and it has been known as a tumor suppressor gene because tumor cells overexpressing alpha5beta1 are less tumorigenic than their parent cells. However, this finding conflicts with some recent data that suggests that the emergence of alpha5beta1 expression correlates with the tumor progression. We, therefore, investigated the expression of alpha5beta1 integrin in 20 lung cancer cell lines by flow cytometric analysis and in 88 node-negative non-small cell lung cancers (NSCLCs) by RT-PCR and immunohistochemical assays to determine the significance of this prognostic factor. In the 20 lung cancer cell lines, 8 (40.0%) cell lines strongly expressed integrin alpha5, 3 (15.0%) cell lines had moderate or weak alpha5 expression, and the remaining 9 (45.0%) cell lines expressed no integrin alpha5. In the 88 node-negative NSCLC patients, 44 samples (50.0%) were evaluated as having integrin alpha5 overexpression, and the integrin alpha5 expression was significantly associated with the status of differentiation and the age of the patients (P = 0.0379 and 0.0312, respectively). In the node-negative patients, the overall survival rate for patients with integrin alpha5 overexpressed tumors was significantly worse than for those individuals whose tumors had normal integrin alpha5 expression (P = 0.016).

Aged↗