Biomedical subjects

M Okamoto

Publications and source records attributed to M Okamoto.

At least 145 records · Page 8Linked to original sources

PubMed2001

Characterization of a proximal element in the rat preadipocyte factor-1 (Pref-1) gene promoter.

Preadipocyte factor-1 (Pref-1) was shown to negatively regulate adipocyte differentiation. We recently reported that ZOG, a rat homolog of Pref-1, was specifically expressed in the adrenal zona glomerulosa. Results of the investigation of Pref-1 expression in preadipocyte and in undifferentiated adrenal cortex suggested that down-regulation of Pref-1 gene was closely correlated with the differentiation process. In this study we demonstrate that an upstream region (from -76 to -47) of the rat Pref-1 gene was essential for its expression in adrenocortical carcinoma-derived H295R cells. A nucleotide sequence found in this region, GCGTGGGCGTGGGCGGGGG (Egr/GC-box), seemed to contain three elements, two early growth response (Egr) elements and one GC-box, overlapping each other. Mutations of four or five nucleotides in a 7-nucleotides-stretch in the midst of the Egr/GC-box eliminated the binding of Sp1/3, abolished the activation by Egr-factor(s) and diminished the Pref-1 promoter activity. When mutations were introduced into the outside of the middle portion, the binding of Sp1/3 to the Egr/GC-box was abolished similarly. However, the decrease in the promoter activity was less than that found with the construct mutated at the middle. These results indicated that an element present at the 7-nucleotides-stretch in the midst of the Egr/GC-box might be important for the Pref-1 promoter activity, and this proximal element was possibly activated by a still-unidentified nuclear factor(s). This element would function as the promoter of the Pref-1 gene in H295R cells, but not in HeLa cells.

Adipocytes↗

PubMed2001

Identification of the rat adrenal zona fasciculata/reticularis specific protein, inner zone antigen (IZAg), as the putative membrane progesterone receptor.

Using immunological methods, a protein specific to the inner zones of the rat adrenal cortex, and called inner zone antigen (IZAg), was previously shown to have two interrelated forms of 26 kDa (IZAg1) and 55-60 kDa (IZAg2), and to have an action on steroid hydroxylation. After two-dimensional gel electrophoresis, and immunoaffinity column purification, N-terminal amino-acid analysis showed that the first 12 amino acids were identical to those of a recently described putative membrane located progesterone receptor (PPMR). RT-PCR was then used to generate the cDNA of this protein, using RNA extracted from rat adrenals. A glutathione S-transferase (GST)-fusion construct was expressed in Escherichia coli, and shown to generate an immunoreactive product of molecular mass consistent with its identification as IZAg1. More detailed examination of the distribution of this protein, not only in the zona fasciculata/reticularis of the adrenal cortex, but also in the Leydig cell, kidney and liver, suggest it may have a role in steroid hormone synthesis and/or metabolism.

Amino Acid Sequence↗

PubMed2001

Highly efficient transfection system for functional gene analysis in adult amphibian lens regeneration.

The analysis of newt lens regeneration has been an important subject in developmental biology. Recently, it has been reported that the genes involved in the normal eye development are also expressed in the regenerative process of lens regeneration in the adult newt. However, functional analysis of these genes has not been possible, because there is no system to introduce genes efficiently into the cells involved in the regeneration. In the present study, lipofection was used as the method for gene transfer in cultured pigmented iris cells that can transdifferentiate into lens cells in newt lens regeneration. Positive expression of a reporter gene was obtained in more than 70% of cells. In addition, the aggregate derived from gene-transfected cells maintained its expression at a high level for a long time within the host tissue. To verify the effectiveness of this model system with a reporter gene in lens regeneration, Pax6, which is suggested to be involved in normal eye development and lens regeneration, was transfected. Ectopic expression of lens-specific crystallins was obtained in cells that show no such activity in normal lens regeneration. These results made it possible for the first time to analyze the molecular mechanism of lens regeneration in the adult newt.

Animals↗

PubMed2001

Morphological spectrum of cyclin D1-positive mantle cell lymphoma: study of 168 cases.

Immunostaining for cyclin D1 is essential for reliable diagnosis of mantle cell lymphoma (MCL). However, a small number of cyclin D1-positive lymphomas other than MCL have been encountered. Our goal was to investigate the morphological spectrum of MCL as a disease entity, based on cyclin D1 overexpression. We reviewed 181 biopsy specimens obtained from 168 cases of cyclin D1-positive MCL. Typical findings were the presence of nodular (53.9% of cases) or diffuse (46.1%) histological patterns, containing mantle zone patterns (16.8%), naked germinal centers (33.5%) and perivascular hyaline deposition (83.2%). Unusual findings of residual germinal centers with a mantle cuff (four cases) and follicular colonization (two cases) were seen. High magnification showed a monotonous proliferation of tumor cells with cytological diversity including small (3.0%), intermediate (43.1%), medium (34.1%), medium-large (13.2%) and large (6.6%) cells. Pleomorphic and blastic/blastoid variants were encountered in 9.6 and 7.2% of cases, respectively. Three cases had foci of cells of considerable size, with a moderately abundant pale cytoplasm resembling marginal zone B cells. Two cases showed an admixture of cells which appeared transformed and mimicked the histology of chronic lymphocytic leukemia/small lymphocytic leukemia. In one, neoplastic mantle zones were surrounded by sheets of mature plasma cells, resembling the plasma cell type of Castleman's disease. An admixture of areas characteristic of MCL and of other larger cells, indicating histological progression or a composite lymphoma, were observed in seven cases. In high-grade lesions of five cases, nuclear staining of cyclin D1 was rarely detected. In our experience, cyclin D1 expression was also found in nine lymphomas other than MCL (five plasma cell myelomas, three Hodgkin's disease and one anaplastic large cell lymphoma). The application of cyclin D1 staining prompted us to recognize the broad morphological spectrum of MCL. MCL can be diagnosed with the application of cyclin D1 immunostaining, if careful attention is given to architectural and cytological features.

Adult↗

PubMed2001

Hypoperfusion following encephalitis: SPECT with acetazolamide.

At 4 weeks and 8 months following initial symptoms, we performed single-photon emission computed tomography (SPECT) with acetazolamide (ACZ) testing in a patient recovering from acute encephalitis, possibly acute disseminated encephalomyelitis (ADEM). Both regional hypoperfusion at baseline and diminished cerebrovascular reserve were seen after focal hyperintensities had disappeared in magnetic resonance imaging (MRI). The time course of SPECT abnormalities reflected the clinical course more closely than the time course of MRI abnormalities. Thus, persistent cerebral circulatory impairment probably contributed to cognitive and language deficits observed at the subacute stage.

Acetazolamide↗

PubMed2001

A case of thrombotic thrombocytopenic purpura refractory to plasma exchange.

We experienced a case of thrombotic thrombocytopenic purpura (TTP) finally relieved after 74 sessions of plasma exchange (PE). The patient was a 56-year-old male. In August 1999, he was examined in emergency because of brown urine and a lowered level of consciousness. As TTP was suspected according to the laboratory findings of abnormally high lactate dehydrogenase and total bilirubin, decreased platelet counts, and numerous fragmented erythrocytes, he was admitted to the ICU of our hospital. Immediately after admission, PE was started consecutively. Upon concomitant use of antiplatelet drugs and prostacyclin, the level of platelet counts recovered to 100,000/microl once, but decreased again. Thus, in addition to the PE, prednisolone and vincristine were administrated, which elevated the level of platelet counts to 200,000 to 300,000/microl. Since the erythrocyte fragmentation was noted frequently, PE was continued twice a week. From the 60th day of admission onward, however, his body temperature rose above 40 degrees C with a rapid increase of C-reactive protein. A blood culture detected methicillin-resistant Staphylococcus aureus (MRSA) which derived from a left lung abscess. During the course of anti-MRSA treatment, he presented acute renal failure and acute hepatic dysfunction, but survived because of the combined therapy. He was discharged on the 180th day of admission. These results suggest that a combined therapy of steroid and vincristine is effective to treat TTP refractory to PE, but careful attention should be paid to the complications caused by immunosuppression.

Combined Modality Therapy↗

PubMed2001

Morphogenesis of primary human biliary epithelial cells: induction in high-density culture or by coculture with autologous human hepatocytes.

Although the control of biliary ductular morphogenesis has received some attention particularly using isolated rat biliary epithelial cell models, the regulation of human bile duct formation is not well defined. In the present study, using a 3-dimensional culture model comprising primary human biliary epithelial cells (BECs) and coculture with primary human hepatocytes, we have sought to define the factors involved. We have shown that primary human BECs can be expanded on collagen gels in the absence of growth factors or serum. When plated in high density in double collagen gels, BECs established 3-dimensional structures that subsequently developed into well differentiated polarized luminal ducts. This morphogenic response occurred in the absence of hepatocyte growth factor (HGF) and epidermal growth factor. Strikingly, the addition of growth factors (in the presence of serum) resulted in loss of polarity although the cells retained growth responses to both factors. Coculture of BECs with autologous human hepatocytes enhanced the ability of low-density BECs to undergo ductulogenesis. This effect was mimicked by addition of conditioned medium from previous hepatocyte-BEC cocultures. These findings indicate that for human biliary ductular morphogenesis, epithelial cell-cell interactions are required but that mesenchymally derived factors such as HGF may not be important.

Bile Ducts↗

PubMed2001

Enhanced production of leukotrienes by peripheral leukocytes and specific IgE antibodies in patients with chronic obstructive pulmonary disease.

BACKGROUND: How leukotrienes (LTs) and IgE-mediated allergy reflect clinical features in patients with chronic obstructive pulmonary disease (COPD) remains unclear. OBJECTIVE: Our goal was to determine whether LTB4 and LTC4 would correlate with airway obstruction and whether IgE-mediated allergy would influence the generation of LTs and bronchial hyperresponsiveness in patients with COPD. METHODS: We measured the pulmonary function, methacholine bronchial hyperresponsiveness, and generation of LTB4 and LTC4 from peripheral leukocytes stimulated with calcium ionophore A23187 in relation to the presence of specific IgE antibodies against inhalant allergens. RESULTS: The leukocytes of patients with COPD generated significantly more LTB4 (with allergy, P <.001; without allergy, P <.001) and LTC4 (with allergy, P <.001; without allergy, P <.01) than the leukocytes of the control subjects. LTC4 production was significantly higher in the allergic COPD subjects than in the nonallergic COPD patients (P <.01), but the amount of LTB4 generated was not significantly different. FEV(1) significantly correlated with the level of both LTB4 (with allergy, r = -0.556, P =.0375; without allergy, r = -0.731, P =.0046) and LTC4 (with allergy, r = -0.764, P =.0043; without allergy, r = -0.526, P =.0414) generation in COPD. The log(10) of the minimum dose of methacholine was significantly higher in COPD patients without allergy than in those with allergy (P <.05). CONCLUSION: Enhanced LT generation from peripheral leukocytes is observed in patients with COPD, and the presence of specific IgE antibodies against inhalant allergens enhances LTC4 generation, bronchial hyperresponsiveness, and the relationship between LTC4 generation and airway obstruction.

Antibodies, Anti-Idiotypic↗

PubMed2001

Clarithromycin-based triple therapy for non-resistant Helicobacter pylori infection. How long should it be given?

BACKGROUND: We have previously reported mixed infection with wild-type (sensitive) and mutant (resistant) Helicobacter pylori strains using a PCR-based preferential homo-duplex formation assay (PCR-PHFA) to detect gene mutations associated with clarithromycin resistance. Half of the cases with mixed infection were determined as sensitive by conventional MIC assessment and yet failed to respond to clarithromycin-based therapy. The aim of this study is to assess the efficacy of clarithromycin-based triple therapy in patients infected exclusively with wild-type strains as determined by PCR-PHFA. METHODS: Ninety patients who had pure wild-type H. pylori infection were randomly assigned to receive clarithromycin (200 mg b.i.d.), amoxicillin (500 mg q.i.d.) and lansoprazole (30 mg b.i.d.) for either 5 days or 7 days (n = 48 and n = 42, respectively). The outcome of eradication was assessed by [13C] urea breath test. RESULTS: Eradication was achieved in 36/48 (75%) versus 39/42 (93%) by intention-to-treat analysis (P = 0.02), and in 36/45 (80%) versus 39/40 (98%) by per protocol analysis (P = 0.01), for the 5-day and 7-day protocols, respectively. Compliance and the incidence of untoward effects were similar in both groups. CONCLUSIONS: Seven-day administration is necessary and sufficient for the triple therapy with clarithromycin, amoxicillin and lansoprazole in patients with pure wild-type H. pylori infection.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2001

Low-attenuation areas of the lungs on high-resolution computed tomography in asthma.

To investigate the low-attenuation areas of the lungs (LAA) in asthma, we compared the mean lung density (MLD) and the LAA in 22 asthmatics (12 ex-smokers and 10 nonsmokers) and 13 patients with chronic obstructive pulmonary disease (COPD) by high-resolution computed tomography. The MLD and the relative area of the lung with attenuation values lower than -950 Hounsfield Units at full inspiration (inspiratory RA950) were significantly different in nonsmoking asthmatics compared to patients with COPD and asthmatics with a smoking history. The MLD and the RA950 correlated significantly with the FEV1 in all groups and with the DL(CO) in patients with COPD and asthmatics with a smoking history but not in nonsmoking asthmatics. We concluded that the LAA in asthmatics with a smoking history indicates the presence of emphysema, but in nonsmoking asthmatics it reflects hyperinflation and nonemphysematous expiratory airflow limitation rather than emphysematous lesions.

Administration, Inhalation↗

PubMed2001

Identification of the HLA-A24 peptide epitope within cytomegalovirus protein pp65 recognized by CMV-specific cytotoxic T lymphocytes.

Among cytomegalovirus (CMV) tegument proteins, phosphoprotein 65 (pp65) has been identified as the important target antigen of the cytotoxic T lymphocyte (CTL) response against the virus. We synthesized seven CMV-pp65-derived peptides carrying an HLA-A24-binding motif, and investigated the ability of these peptides to induce CMV-specific CTL. We identified one nonamer peptide (pp65113-121; VYALPLKML) able to bind HLA-A24 and induce CTL responses in vitro in peripheral blood mononuclear cells (PBMC) from CMV-seropositive individuals. The peptide-specific CTLs generated were capable of recognizing pp65 expressed on CMV-infected fibroblasts as well as pp65113-121 peptide bound to the surface of C1R-A*2402 cells in an HLA-A24-restricted manner. The pp65113-121 peptide thus might be considered a synthetic peptide vaccine in HLA-A24-positive individuals.

Antigens, Viral↗

PubMed2001

Coaggregation of Porphyromonas gingivalis and Prevotella intermedia.

Porphyromonas gingivalis cells coaggregated with Prevotella intermedia cells. The coaggregation was inhibited with L-arginine, L-lysine, Nalpha-p-tosyl-L-lysine chloromethyl ketone, trypsin inhibitor, and leupeptin. Heat- and proteinase K-treated P. gingivalis cells showed no coaggregation with P. intermedia cells, whereas heat and proteinase K treatments of P. intermedia cells did not affect the coaggregation. The vesicles from P. gingivalis culture supernatant aggregated with P. intermedia cells, and this aggregation was also inhibited by addition of L-arginine or L-lysine and by heat treatment of the vesicles. The rgpA rgpB, rgpA kgp, rgpA rgpB kgp, and rgpA kgp hagA mutants of P. gingivalis did not coaggregate with P. intermedia. On the other hand, the fimA mutant lacking the FimA fimbriae showed coaggregation with P. intermedia as well as the wild type parent. These results strongly imply that a heat-labile and proteinous factor on the cell surface of P gingivalis, most likely the gingipain-adhesin complex, is involved in coaggregation of P. gingivalis and P. intermedia.

Adhesins, Bacterial↗

PubMed2001

Frameshift mutations at mononucleotide repeats in RAD50 recombinational DNA repair gene in colorectal cancers with microsatellite instability.

To identify additional genes targeted for microsatellite instability (MSI), we search for human genes which contain mononucleotide repeats in their coding region, selected 7 genes (RAD50, DNA-PKcs, FLASH, Apaf-1, XPG, CtIP, and MLSN1), and analyzed frameshift mutations in them. Here we report that 60% (3 out of 5) of human colorectal cancer cell lines exhibiting a high frequency of MSI (MSI-H) and 46% (6 out of 13) of MSI-H primary colorectal tumors had mutations in the (A)9 repeat of RAD50 recombinational repair gene. In contrast, no frameshift mutations were found in any of the 5 MSI-negative colorectal cancer cell lines, 8 colorectal tumors exhibiting a low frequency of MSI (MSI-L), or 28 MSI-negative colorectal tumors. No mutations were found in the mononucleotide repeats of 6 other genes, even in MSI-H cancers. These results suggest that RAD50 frameshift mutations may play a role in the tumorigenesis of MSI-H colorectal cancers.

Colorectal Neoplasms↗

PubMed2001

[An adult case of systemic cat-scratch disease with hepatosplenic involvement].

A previously healthy 25-year-old female was admitted to our hospital in November, 1997, for treatment of a spike-fever of 2 weeks' duration. She had a cat in her house but reported no history of cat bites or scratches. No peripheral lymphadenopathy was detected. White blood cell count was within normal limits, but an increased C-reactive protein level of 11.4 mg/dl was noted. Infectious disease was suspected but ruled out as blood cultures were negative. Empiric therapy with clarithromyoin, isoniazid, and rifampicin was ineffective. In January, 1998, abdominal ultrasonogram revealed multiple hypoechoic mass lesions in the spleen and liver, and a splenectomy was performed in March. Histopathologic examination showed numerous necrotizing and caseating granulomas, which tested positive for Bartonella henselae DNA by PCR. Furthermore, the patient tested positive for B. henselae antibody by immunofluorescence assay. A diagnosis of systemic cat-scratch disease with hepatospnenic involvement was made. Combination therapy with minocycline, sulbactam/cefoperazone, and tosufloxacin was administered and her inflammatory findings improved gradually. We report an adult case of systemic cat-scratch disease with liver and spleen involvement in the non-immunocompromised host.

Adult↗

PubMed2001

Inverse background of Helicobacter pylori antibody and pepsinogen in reflux oesophagitis compared with gastric cancer: analysis of 5732 Japanese subjects.

BACKGROUND: The relationship between Helicobacter pylori and reflux oesophagitis remains controversial. AIMS: To evaluate the relationship between H pylori and reflux oesophagitis in a large number of Japanese subjects. SUBJECTS: A total of 5732 consecutive Japanese subjects during a health screening were enrolled. METHODS: Gastrointestinal endoscopy was performed on all subjects. We simultaneously measured serum anti-H pylori antibody and pepsinogen as markers of H pylori infection together with gastric atrophy. The risk of reflux oesophagitis was evaluated in relation to these markers, and the results were compared with those of gastric cancer. RESULTS: Reflux oesophagitis was found in 108 subjects. Both positivity for H pylori antibody (adjusted odds ratio (OR) 0.67 (95% confidence interval 0.45-1.0)) and "low" pepsinogen indicating gastric atrophy (OR 0.35 (0.18-0.68)) were negatively associated with reflux oesophagitis. After subjects were classified into four groups based on positivity or negativity for H pylori antibody and "low" pepsinogen, the prevalence of reflux oesophagitis showed a decreasing trend as H pylori induced gastric atrophy became more severe. The risk of gastric cancer showed an increasing trend, exactly the opposite to that of reflux oesophagitis. CONCLUSIONS: Analysis of a large series of Japanese subjects revealed a decreasing prevalence of reflux oesophagitis in conjunction with progress of gastric atrophy induced by H pylori infection. This pattern was completely opposite to that of gastric cancer cases. A protective role of H pylori for reflux oesophagitis through the development of gastric atrophy has been suggested.

Adult↗

PubMed2001

Influence of age and disease severity on high resolution CT lung densitometry in asthma.

BACKGROUND: Low attenuation areas (LAA) on computed tomographic (CT) scans have been shown to represent emphysematous changes in patients with chronic obstructive pulmonary disease (COPD). However, the significance of LAA is still controversial in patients with asthma. This study was undertaken to assess the usefulness of lung CT densitometry in the detection of airspace enlargement in association with asthma severity. METHODS: Forty five asthmatic subjects and 15 non-smoking controls were studied to determine the influence of age, pulmonary function, and asthma severity on mean lung density (MLD) and the relative area of the lung showing attenuation values less than -950 HU (RA(950)) on high resolution CT (HRCT) scans. RESULTS: In asthmatic patients both MLD and RA(950) correlated with parameters of airflow limitation (%FEV(1), FEV(1)/FVC, %FEF(25-75)) and lung volume (%TLC, %FRC, %RV), but not with lung transfer factor (%TLCO, %TLCO/VA). The results of HRCT lung densitometry also correlated with patient age and severity of asthma. CONCLUSIONS: Decreased CT lung density in non-smoking asthmatics is related to airflow limitation, hyperinflation and aging, but not with lung transfer factor.

Adult↗

PubMed2001

Development of a system for the inference of large scale genetic networks.

We propose a system named AIGNET (Algorithms for Inference of Genetic Networks), and introduce two top-down approaches for the inference of interrelated mechanism among genes in genetic network that is based on the steady state and temporal analyses of gene expression patterns against some kinds of gene perturbations such as disruption or overexpression. The former analysis is performed by a static Boolean network model based on multi-level digraph, and the latter one is by S-system model. By integrating these two analyses, we show our strategy is flexible and rich in structure to treat gene expression patterns; we applied our strategy to the inference of a genetic network that is composed of 30 genes as a case study. Given the gene expression time-course data set under the conditions of wild-type and the deletion of one gene, our system enabled us to reconstruct the same network architecture as original one.

Algorithms↗

PubMed2001

Three-dimensional analysis of morphological aspects of the human saccular macula.

The 3-dimensional shape of the human saccular macula and its orientation in the skull were quantitated in this study. The semicircular canals and saccular maculae were reconstructed 3-dimensionally on a computer from 3 human temporal bones. The 380 to 522 triangles in the entire area of the saccular macula were made by drawing lines between 2 adjacent points every 100-pm width of the saccular macula in each section. The angles between each triangle and each estimated standard axis in the skull obtained were calculated. This information will provide standard data regarding the 3-dimensional morphological aspects of the saccular macula for further investigations of the function of the sacculus. It was determined that the 3-dimensional shape of the saccular macula was not a plane, but was a curved surface like that of an ellipsoid. It is thought that this shape is necessary in order for the saccular macula to detect wide-range linear acceleration.

Acoustic Maculae↗