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Biomedical subjects

K Kawakami

Publications and source records attributed to K Kawakami.

At least 199 records · Page 11Linked to original sources
PubMed1998

Dominant negative ATF1 blocks cyclic AMP-induced neurite outgrowth in PC12D cells.

Extension of the neuronal process is a crucial step for establishment of the neuronal network. As CREB preferentially forms heterodimers with ATF1 in PC12D cells, we examined the roles of the CREB/ATF1 heterodimer on cyclic AMP (cAMP)-induced neurite extension, using originally constructed ATF1RL, which has a point mutation at the DNA binding domain of ATF1. Transient expression of ATF1RL suppressed the protein kinase A/CREB-induced expression of the CRE reporter gene as expected. Treatment with forskolin elicited a relatively poor mRNA induction for immediate early genes in PC12D-ATF1 RL cells, a PC12D cell line stably expressing ATF1RL, in comparison with the parental PC12D cells. Furthermore, the PC12D-ATF1RL cells were proved to be defective at cAMP-induced neurite outgrowth. In contrast, both the gene expression and the differentiation after nerve growth factor treatment noted in PC12D-ATF1RL cells were at the same levels as those in the parental cells. These data provide us the first evidence that links CREB/ATF1 to the cAMP-induced differentiation of PC12 cells.

Activating Transcription Factor 1↗
PubMed1998

Corticosterone and 11-dehydrocorticosterone stimulate Na,K-ATPase gene expression in vascular smooth muscle cells.

BACKGROUND: In mineralocorticoid target tissues such as kidney and colon, the enzyme 11 beta-hydroxysteroid dehydrogenase (11 beta OHSD) catalizes the reversible conversion of corticosterone (CS) to inactive 11-dehydrocorticosterone (DHCS) in rats, and cortisol to inactive cortisone in humans. This enzyme is also expressed in vascular smooth muscle cells (VSMC). METHODS: In cultured VSMC from rat thoracic aortae, we examined the effects of CS and DHCS on Na,K-ATPase alpha 1- and beta 1-mRNA accumulation by Northern blot analysis, on alpha 1- and beta 1-subunit protein accumulation by Western blot analysis, and on Na,K-ATPase activity by the coupled assay method. RESULTS: In VSMC, CS and DHCS (10(-6) M) increased alpha 1-mRNA level 2.6- and 2.5-fold at 48 hours and beta 1-mRNA level 9.2- and 9.1-fold at 12 hours, respectively. The RNA transcription inhibitor (actinomycin D) abolished both CS- and DHCS-mediated alpha 1- and beta 1-mRNA induction. The glucocorticoid receptor antagonist (RU38486) and the mineralocorticoid receptor antagonists (ZK91587) inhibited both CS- and DHCS-mediated alpha 1- and beta 1-mRNA induction. The 11 beta OHSD inhibitor (carbenoxolone) inhibited DHCS-mediated alpha 1- and beta 1-mRNA induction, whereas it caused no effect on CS-mediated alpha 1- or beta 1-mRNA induction. The addition of CS or DHCS to VSMC significantly increased alpha 1- and beta 1-subunit protein levels and Na,K-ATPase activity. When adrenalectomized rats were treated with CS or DHCS for 12 hours, aorta alpha 1- and beta 1-mRNA levels increased 3.0- and 8.7-fold or 3.4- and 8.4-fold, respectively. CONCLUSIONS: In VSMC, both CS and DHCS stimulate Na,K-ATPase alpha 1- and beta 1-mRNA accumulation, alpha 1- and beta 1-subunit protein accumulation, and Na,K-ATPase activity. The CS-mediated alpha 1- and beta 1-mRNA induction occurs independently of 11 beta OHSD, whereas the DHCS-mediated alpha 1- and beta 1-mRNA induction occurs through 11 beta OHSD-dependent mechanisms, possibly via conversion of inactive DHCS into active CS.

Animals↗
PubMed1998

Promoter of mDMAHP/Six5: differential utilization of multiple transcription initiation sites and positive/negative regulatory elements.

We analyzed the expression of mouse DMAHP / Six5 (the myotonic dystrophy-associated homeodomain protein gene) during embryogenesis and in various tissues by northern blotting. Expression was observed as early as embryonic day 7 (E7) and continued to E17. Abundant expression was observed in neonatal heart and skeletal muscle with potential links to the phenotype of myotonic dystrophy. The transcription initiation sites of the gene were analyzed in mouse E11 and E15 embryos and in adult skeletal and heart muscle. Three major transcription initiation sites were identified, the proximal site was specific to the early E11 embryo, while the other two were common among the heart and skeletal muscle and E11 and E15 embryos. All transcription initiation sites were downstream of the corresponding CTG repeat locus of the mouse gene (-1195), excluding a possible inclusion of the CUG repeat sequence in mRNA leading to abnormal splicing or to translation of aberrant protein. For analysis of the regulatory elements in the promoter region, we used P19 embryonal carcinoma cells which abundantly express mouse DMAHP / Six5. Multiple positive and negative elements were identified in the promoter region. All positive elements were Sp1/Sp3 binding sites and one of the negative elements was a novel factor binding site. The transcription initiation sites and regulatory elements are conserved between human and mouse DMAHP.

Animals↗
PubMed1998

Isolation of pathogenic bacteria from induced sputum from hospitalized children with pneumonia in Bangladesh.

A prospective study was carried out on 157 patients admitted to a paediatric hospital in Dhaka, Bangladesh to determine the bacteria present in the induced sputum of paediatric patients with X-ray proven pneumonia. Their ages ranged from 21 days to 11 years; 65 per cent of them were male and 35 per cent were female. The most affected age group was between 6 months and 2 years old. Respiratory secretions produced by induced cough were taken by swab from the oropharynx for culture and smear. The predominant bacteria were Haemophilus influenzae, Streptococcus pneumoniae, Branhamella catarrhalis and Gram-negative bacilli. Serotyping of H. influenzae revealed that 76 per cent were non-typable and 18 per cent were of type b; 23.5 per cent of isolates of H. influenzae were beta-lactamase producing. MIC90 of penicillin against S. pneumoniae and H. influenzae were 0.025 and 3.13 micrograms/ml respectively. Ampicillin, penicillin G (benzylpenicillin), amoxycillin, and gentamicin were administered for the treatment of these patients. All cases were apparently improved, on the basis of clinical evaluation, and discharged from the hospital.

Age Distribution↗
PubMed1998

Attachment of nontypable Haemophilus influenzae to human pharyngeal epithelial cells mediated by a ganglioside receptor.

Nontypable Haemophilus influenzae (NTHI) is one of the major pathogens of human respiratory infections and has the ability to attach to pharyngeal epithelial cells. We characterized the epithelial cell receptor to which NTHI bind. Neuraminidase pretreatment of pharyngeal epithelial cells resulted in a significant decrease in NTHI attachment, suggesting sialic acid as an important component of the receptor. The attachment was not decreased in NTHI pretreated with 1,000 microg/ml of fucose, N-acetyl-neuraminic acid, N-acetyl-glucosamine, N-acetyl-galactosamine, acetyl-salicylic acid and colominic acid. Only treatment with gangliosides D1a, D1b and D2 at a concentration of 12.5 microg/ml significantly decreased the attachment. On the other hand, treatment with gangliosides M1, M2, M3, D3, T1b and asialoganglioside M1 did not decrease the attachment of NTHI. Only ganglioside D2 inhibited the attachment significantly at a concentration of 12.5 ng/ml. Other isolates of NTHI showed a decrease in attachment after treatment with ganglioside D2. Treatment of cells with anti-human GD2 monoclonal antibody also decreased the attachment of NTHI in a dose-dependent manner. This study indicates that sialic acid glycoconjugate, GD2, is one of the receptors of NTHI on human pharyngeal epithelial cells.

Antibodies, Monoclonal↗
PubMed1998

[Complication of infection in malnutritional status].

Recently, the therapeutic guideline has been mentioned in opportunistic infection of the compromised host, and many observations regarding complication of infection in these hosts have been reported. However, there were few reports in the relationship between infection and immune function or nutritional status. In this study, we confirmed that the nutritional status influences immune function in patients with lung cancer, hepatoma and renal failure, and that malnutrition markedly reduces their immunity. In patients after operation who where the pre-operative assessment of the nutritional status was performed an attempt to improve the nutritional status has been already made to improve their prognosis. Therefore, we emphasize that the management of the nutritional status even in hosts with many other diseases is thought to be important in protection against infection and prognosis of the disease.

Adult↗
PubMed1998

Simplified quantitative assay system for measuring activities of drugs against intracellular Legionella pneumophila.

We developed a new simple assay for the quantitation of the activities of drugs against intracellular Legionella pneumophila. The cells of a murine macrophage-like cell line (J774.1 cells) allowed the intracellular growth and replication of the bacteria, which ultimately resulted in cell death. The infected J774.1 cell monolayers in 96-well microplates were first treated with antibiotics and were further cultured for 72 h. The number of viable J774.1 cells in each well was quantified by a colorimetric assay with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and an enzyme-linked immunosorbent assay reader. The number of growing bacteria in each well was also determined by counting the numbers of CFU on buffered charcoal yeast extract-alpha agar plates. Viable J774.1 cell counts, determined by the colorimetric assay, were inversely proportional to the number of intracellular replicating bacteria. The minimum extracellular concentrations (MIECs) of 24 antibiotics causing inhibition of intracellular growth of L. pneumophila were determined by the colorimetric assay system. The MIECs of beta-lactams and aminoglycosides were markedly higher than the MICs in buffered yeast extract-alpha broth. The MIECs of macrolides, fluoroquinolones, rifampin, and minocycline were similar to the respective MICs. According to their intracellular activities, clarithromycin and sparfloxacin were the most potent among the macrolides or fluoroquinolones tested in this study. Our results indicated that the MTT assay system allows comparative and quantitative evaluations of the intracellular activities of antibiotics and efficient processing of a large number of samples.

Anti-Bacterial Agents↗
PubMed1998

Involvement of negative cofactor NC2 in active repression by zinc finger-homeodomain transcription factor AREB6.

The transcription factor AREB6 contains a homeodomain flanked by two clusters of Krüppel type C2H2 zinc fingers. AREB6 binds to the E-box consensus sequence, CACCTGT, through either the N- or the C-terminal zinc finger cluster. To gain insights into the molecular mechanism by which AREB6 activates and represses gene expression, we analyzed the domain structure of AREB6 in the context of a heterologous DNA-binding domain by transient-transfection assays. The C-terminal region spanning amino acids 1011 to 1124 was identified as a conventional acidic activation domain. The region containing amino acids 754 to 901, which was identified as a repression domain, consists of 40% hydrophobic amino acids displaying no sequence similarities to other known repression domains. This region repressed transcription in vitro in a HeLa nuclear extract but not in reconstituted transcription systems consisting of transcription factor IID (TFIID), TFIIB, TFIIE, TFIIH/F, and RNA polymerase II. The addition of recombinant negative cofactor NC2 (NC2alpha/DRAP1 and NC2beta/Dr1) to the reconstituted transcription system restored the activity of the AREB6 repression domain. We further demonstrated interactions between the AREB6 repression domain and NC2alpha in yeast two-hybrid assay. Our findings suggest a mechanism of transcriptional repression that is mediated by the general cofactor NC2.

Animals↗
PubMed1998

Regulation of Na-K-ATPase gene expression by hyperoxia in MDCK cells.

Na-K-ATPase plays a central role in a variety of physiological processes, including ion transport and regulation of cell volume. Our previous data showed that hyperoxia increased the expression of Na-K-ATPase alpha 1 and beta 1 mRNA in lung type II cells. We similarly show that hyperoxia (> or = 95% O2 for 24-48 h) increased steady-state mRNA levels in both Na-K-ATPase subunits in Madin-Darby canine kidney (MDCK) cells. The mechanism of gene regulation by hyperoxia was assessed. Stability of the Na-K-ATPase mRNA levels of both subunits was unchanged in hyperoxia-exposed MDCK cells. To determine whether gene transcription was augmented by hyperoxia, MDCK cells were transfected with a beta 1-subunit promoter-reporter construct. Transfection with the wild-type promoter (beta 1-817) revealed a 1.9 +/- 0.2-fold increase in promoter activity. Transfection with 5' deletion constructs identified a 61-base pair (bp) region between -102 and -41 that was necessary for this increase in promoter activity by hyperoxia. Incorporation of this 61-bp region into a minimal promoter (mouse mammary tumor virus) similarly increased promoter activity 2.3-fold in the presence of hyperoxia. This increase in promoter activity was not seen when MDCK cells were incubated with various concentrations of hydrogen peroxide. In summary, hyperoxia increased Na-K-ATPase beta 1-subunit mRNA steady-state level due to increased transcription in MDCK cells. A region necessary for this hyperoxic effect on beta 1 transcription is located between base pairs -102 and -41 on the promoter.

Animals↗
PubMed1998

Overexpression of the forebrain-specific homeobox gene six3 induces rostral forebrain enlargement in zebrafish.

The Drosophila homeobox gene sine oculis is expressed in the rostral region of the embryo in early development and is essential for eye and brain formation. Its murine homolog, Six3, is expressed in the anterior neural plate and eye anlage, and may have crucial functions in eye and brain development. In this study, we describe the cloning and expression of zebrafish six3, the apparent ortholog of the mouse Six3 gene. Zebrafish six3 transcripts are first seen in hypoblast cells in early gastrula embryos and are found in the anterior axial mesendoderm through gastrulation. six3 expression in the head ectoderm begins at late gastrula. Throughout the segmentation period, six3 is expressed in the rostral region of the prospective forebrain. Overexpression of six3 in zebrafish embryos induced enlargement of the rostral forebrain, enhanced expression of pax2 in the optic stalk and led to a general disorganization of the brain. Disruption of either the Six domain or the homeodomain abolish these effects, implying that these domains are essential for six3 gene function. Our results suggest that the vertebrate Six3 genes are involved in the formation of the rostral forebrain.

Amino Acid Sequence↗
PubMed1998

Synthesis and antibacterial activity of novel pyridobenzoxazine analogues.

A series of novel LVFX (7) analogues bearing 4,4-dialkyl-3-aminopyrrolidines at the C-10 position of pyridobenzoxazine was synthesized and their antibacterial activities, pharmacokinetics and acute toxicities in animals were evaluated. Non-alkylated pyrrolidine derivative 26a showed greater activity than LVFX (7) against gram-positive and gram-negative bacteria including Pseudomonas aeruginosa, but 26a possessed high acute toxicity in mice and unfavorable pharmacokinetics in rats. When compared with 26a, 4,4-dialkylated derivatives 26c, e.g. showed more potent activity against gram-positive bacteria along with an improvement of pharmacokinetics and reduction of acute toxicity. Increases in lipophilicity by alkylation on the pyrrolidine ring resulted in a good influence on the above profiles.

Animals↗
PubMed1998

Low density lipoprotein particle size is associated with glycosylated hemoglobin levels regardless of plasma lipid levels.

We evaluated the influence of the levels of glycosylated hemoglobin (HbA1C) and fasting plasma glucose on the variation in low density lipoprotein (LDL) peak particle size in 210 subjects who were undergoing an annual check-up. Univariate analysis showed that LDL particle size was significantly and positively correlated with high density lipoprotein (HDL) cholesterol levels, and was inversely correlated with the levels of total plasma cholesterol, triglycerides, fasting glucose, fasting insulin, HbA1C, and body mass index (BMI). Stepwise regression analysis selected four independent contributing variables that could affect LDL particle size; triglyceride levels, HDL cholesterol levels, LDL cholesterol levels, and HbA1C levels. Similar regression analysis performed for men and for normotensive subjects showed that HbA1C levels also independently influenced LDL particle size. The results indicate that HbA1C levels have a significant effect on LDL particle size. This suggests that small LDL particles would be present in subjects with non-insulin-dependent diabetes mellitus regardless of plasma lipid concentrations.

Adult↗
PubMed1998

Thymic carcinoma associated with a high serum level of interleukin 6 diagnosed through the evaluation for asymptomatic elevation of acute-phase reactants.

A case of thymic squamous cell carcinoma producing interleukin-6 (IL-6) is reported. C-reactive protein (CRP), white blood cell (WBC) count, and serum IL-6 had been elevated, and normalized immediately after tumorectomy. IL-6 in the culture supernatant from the tumor was significantly elevated and the expression of IL-6 mRNA was demonstrated in the tumor by a reverse transcriptase polymerase chain reaction method. Immunohistochemical study demonstrated that tumor cells were stained positive with an anti-IL-6 antibody. IL-6 derived from the tumor cells reflected the increase CRP and WBC counts. This case suggested that asymptomatic elevation of acute-phase reactants might be clues for the diagnosis of an IL-6 producing tumor.

Acute-Phase Proteins↗
PubMed1998

[Orbito-facial reconstruction after extensive anterior skull base, head and neck resection using a rectus abdominis musculocutaneous flap].

In response to the recent advances in aggressive excision of skull base and head and neck malignancies, a more sophisticated method primary reconstruction has been developed using a craniofacial techniques for preservation of postoperative quality of life. We have developed an inferior pedicled rectus abdominis musculocutaneous flap with rib cartilages for reconstruction of the orbito-facial region. The advantages of this flap are as follows; 1) Simultaneous flap elevation in a supine position is possible, 2) Easy, versatile and reliable flap adjustment can be made for complicated space defect, 3) Curvature of the ipsilateral rib cartilages is suitable for inferior orbital rim, 4) Lower risk of pleura laceration as compared with a superior pedicled flap. In the past 5 years, the composite free flaps have been applied for 3 cases of hemi orbito-facial defect, with better results than in previous cases. Our technique for the flap application in a representative case is illustrated.

Head and Neck Neoplasms↗
PubMed1998

[Surgical technique of endoscopic transthoracic sympathicotomy: axillary approach].

A total of 181 endoscopic transthoracic sympathicotomy were performed at our hospital from December, 1992 to March, 1997. After single-lumen endotracheal intubation for general anesthesia, the patient was placed in half sitting position. A small (1 cm) incision was made in the anterior axillary line through the third intercostal space and an apical pneumothorax was created by insufflation of 1.8 L of CO2 in the pleural cavity through a Surgineedle. A 24 Fr. urological transurethral electroresectoscope was introduced through the same incision. The sympathetic chain could be observed through parietal pleura riding on the costovertebral junctions. In palmar hyperhidrosis the second and third thoracic sympathetic ganglia were electrocoagulated. In axillary hyperhidrosis the forth ganglion was included. The lung was expanded by limiting expiration and sucking CO2. The operation was repeated on the other side. Endoscopic transthoracic sympathicotomy was an efficient, safe and low invasive surgical procedure for the treatment of palmar, axillary hyperhidrosis, Raynaud's disease and Buerger disease.

Axilla↗
PubMed1998

Tissue and developmental distribution of Six family gene products.

To examine the presence and distribution of Six family gene products in a variety of tissues at various developmental stages and in various cell types, we prepared specific antibodies against recombinant Six gene products. The distribution of Six2 and Six4 was examined by immunostaining in the developing mouse embryo. Production of Six2 was detected at E8.5 mainly in the mesenchyme, while Six4 was present in nuclei of neuronal cells in the peripheral region of the mantle layer of developing brain and spinal cord and in various ganglia at E10.5 and E11.5. Specific DNA binding activities of the Six proteins were analyzed by gel retardation super-shift assays using nuclear extracts from different rat tissues and cell lines. Six5 was the dominant isoform observed in the adult kidney, liver and lung but not in the brain. Six4 was not detected in all tested adult tissues, however, it was present in embryonic (FD21) lung nuclear extracts. In contrast, Six4 was detected in a variety of cultured cell lines, including HeLa, 3T3, MDCK and C2C12. Our results suggest that Six4 plays a specific role in the differentiation or maturation of neuronal cells, while Six5 is an adult type Six gene isoform product and is distributed in the kidney, liver and lung.

3T3 Cells↗