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Biomedical subjects

M Kawano

Publications and source records attributed to M Kawano.

At least 55 records · Page 3Linked to original sources
PubMed2000

Induction of c-Src in human blood monocytes by anti-CD98/FRP-1 mAb in an Sp1-dependent fashion.

Freshly isolated human blood monocytes expressed neither c-src mRNA nor c-Src. However, when monocytes were incubated with anti-CD98 heavy chain (HC) mAb, expression of c-src mRNA, c-Src, and activated c-Src was induced. Many binding sites for the ubiquitous transcription factor Sp1 were identified in the promoter region of the c-src gene. Surprisingly, Sp1 and Sp1 mRNA were not found in monocytes that were freshly isolated or incubated with control antibody. Stimulation with anti-CD98HC mAb also resulted in the expression of Sp1 and its translocation to the nucleus. Herbimycin A, genistein, manumycin A, PD-98059, SB203580, and HBJ127 suppressed CD98HC-mediated c-src and Sp1 mRNA induction. On the contrary, H-7, Wortmannin, HA1077, and Y-27632 showed no effect on c-Src and Sp1 induction. Furthermore, anti-CD98HC mAb induced activation of tyrosine kinases and ERK kinases. These findings suggest that the tyrosine kinase(s)-Ras-MAPK-Sp1 pathway(s) is involved in CD98HC-mediated induction of c-Src in human blood monocytes.

Antibodies, Monoclonal↗
PubMed2000

pH-dependent reversible inhibition of violaxanthin de-epoxidase by pepstatin related to protonation-induced structural change of the enzyme.

The redox enzyme violaxanthin de-epoxidase (VDE) was found to be sensitive to pepstatin, a specific inhibitor of aspartic protease. The inhibition was similar to that of aspartic protease in that it was reversible and accompanied by the protonation of the enzyme. Of the two peaks of VDE appearing on anion exchange chromatography, VDE-I predominated at pH 7.2. On lowering the pH of the chromatography, VDE-I decreased and VDE-II increased. Furthermore, re-chromatography of either peak yielded both peaks. These results suggest that VDE-I and VDE-II are interconvertible depending on pH, and thus, they represent the de-protonated and protonated forms of the enzyme, respectively. Presumably the protonation-induced structural change of the enzyme is responsible for the interaction with pepstatin, and also with substrate.

Chromatography, Ion Exchange↗
PubMed2000

Adjuvant effect of antibodies against von Willebrand Factor, fibrinogen, and fibronectin on staphylokinase-induced thrombolysis as measured using mural thrombi formed in rat mesenteric venules.

The change in thrombus mass during thrombolytic therapy is thought to be the difference between its growth and its degradation induced by thrombolytic agents. Platelets play a pivotal role in arterial thrombosis and bind to each other and to exposed subendothelial matrices via adhesive proteins such as von Willebrand Factor, fibrinogen, and fibronectin. The aim of the present study was to assess whether administration of antibodies against these adhesive proteins, in conjunction with plasminogen activator, could enhance the degradation of platelet-rich thrombus. Mural platelet-rich thrombi were formed in rat mesenteric venules using He-Ne laser irradiation. Recombinant staphylokinase was infused continuously and polyclonal antibodies against adhesive proteins were given by bolus injection. The thrombolytic process was analysed using computer-enhanced image analysis software. Administration of each of the antibodies enhanced staphylokinase-induced thrombolysis.

Adjuvants, Immunologic↗
PubMed2000

Spindle-shaped cells derived from giant-cell tumor of bone support differentiation of blood monocytes to osteoclast-like cells.

Spindle-shaped cells were established from four giant-cell tumors of bone. When human blood monocytes were co-cultured with these cells, multinucleated giant-cell formation of monocytes was induced. Intriguingly, even when a filter (pore size: 0.45 microm) was interposed between monocytes and the spindle-shaped cells, polykaryocytes also appeared. These multinucleated giant cells were positive for tartrate-resistant acid phosphatase, expressed calcitonin receptor, and showed bone-resorption activity, characteristics of osteoclast-like cells. These findings indicate that soluble factors secreted from these cells play an important role in osteoclast-like cell formation from blood monocytes. These data additionally suggest that these cells support osteoclast-like cell formation in giant-cell tumors of bone. The cells also expressed mannose receptor, fibronectin, receptor activator of nuclear factorkappaB, and several cytokine mRNAs, including interleukin-6, receptor activator of nuclear factorkappaB ligand/osteoclast differentiation factor/osteoprotegerin ligand, and macrophage colony-stimulating factor. However, all of these molecules except receptor activator of nuclear factorkappaB ligand mRNA could also be detected in control HeLa and CV-1 cells. Although the soluble receptor activator of nuclear factorkappaB ligand has not been found under physiological conditions, it is possible that it is cleaved by cellular proteases and the truncated receptor activator of nuclear factorkappaB is released from cells. Identification of the soluble factors capable of inducing osteoclast formation from blood monocytes is a pressing problem to be solved.

Bone Neoplasms↗
PubMed2000

N-glycosylation contributes to the limited cross-reactivity between hemagglutinin neuraminidase proteins of human parainfluenza virus type 4A and 4B.

cDNAs encoding human parainfluenza virus type 4B (hPIV-4B) hemagglutinin neuraminidase (HN) protein were cloned and the nucleotide sequences were determined. A high degree of identity (81.4%) was observed between the nucleotide sequences of hPIV-4A and -4B HN proteins, and an 87.3% identity was found between the deduced amino acid sequences. This degree of identity is considered to be greater than immunological similarity between hPIV-4A and -4B HN proteins determined using monoclonal antibodies. To elucidate the causes of the antigenic difference between HN proteins of hPIV-4A and -4B, we constructed three cDNAs of hPIV-4B HN whose potential N-glycosylation sites were partially or completely the same as in hPIV-4A HN cDNA. We compared the antigenicity of the expressed wild-type and mutant proteins, and found that the antigenicities of the mutant hPIV-4B HN proteins were more similar to the hPIV-4A HN protein than to the non-mutant hPIV-4B HN protein. This study indicated that the antigenic diversity between hPIV-4A and -4B was partly caused by deletion or creation of glycosylation sites, showing that the point mutations resulting in deletion or creation of glycosylation sites is one of the initial steps leading to the division of virus into subtypes.

Amino Acid Sequence↗
PubMed2000

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), and organochlorine pesticides in yellow-blotched map turtle from the Pascagoula River basin, Mississippi, USA.

Concentrations of polychlorinated-dibenzo-p-dioxins (PCDDs), -dibenzofurans (PCDFs), -biphenyls (PCBs), and organochlorine pesticides were measured in tissues of map turtles collected from two locations in the Pascagoula River drainage of Mississippi, USA. PCBs were most predominant among the organochlorines with a concentration of up to 99 ng/g, wet weight (580 ng/g, lipid weight) in livers. The greatest concentration of PCDDs/DFs of 1.1 pg/g, wet weight (15.76 pg/g, lipid weight) was found in the liver of a male turtle. The measured concentrations of organochlorines were less than those reported for turtles from the Great Lakes Basin and upper St. Lawrence River. PCBs contributed 90-99% of the total estimated 2, 3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs). Particularly, PCB congeners 105, 118, and 156 accounted for 68-80% of the estimated toxic potency of PCBs in turtles.

Animals↗
PubMed2000

Gated SPET quantification of small hearts: mathematical simulation and clinical application.

Quantification of gated single-photon emission tomography (SPET) in small hearts has been considered to be inaccurate. To evaluate the validity of gated SPET in a small chamber volume, mathematical simulation and clinical application to paediatric patients were performed. Myocardium with various chamber sizes from 14 ml to 326 ml was generated assuming an arbitrary resolution (6.9-15.7 mm in full-width at half-maximum), noise and zooming factors. The cut-off frequency of the Butterworth filter for preprocessing was varied from 0.16 to 0.63 cycles/cm. The chamber volume was calculated by quantitative gated SPET software (QGS). The patients, aged 2 months to 19 years (n=27), were studied by gated technetium-99m methoxyisobutylisonitrile or tetrofosmin SPET. Image magnification as large as possible was performed during data acquisition to include the whole chest using 1.25-2.0 zooming. Based on the simulation study, an underestimation of the chamber volume occurred below a volume of 100 ml. The degree of underestimation for a 37-ml volume was 49% without zooming, but it improved to 3% with 2x zooming. Filters with a higher cut-off frequency, better system resolution and hardware zooming during acquisition improved quantitative accuracy in small hearts. For the subjects under 7 years old (n=7), quantification of volume and ejection fraction (EF) was possible in 72% of the patients. In those over 7 years old, gated SPET quantification was feasible in all cases. The correlation between gated SPET end-diastolic volume (SPET EDV) and both echocardiographic end-diastolic dimension (EDD) and echocardiographic EDV was good (r=0.84 between SPET EDV and echo EDD, r=0.85 between SPET EDV and echo EDV, P<0.0001 for both). The correlation between gated SPET EF and both echocardiographic fractional shortening (FS) and echocardiographic EF was fair (r=0.69 between SPET EF and echo FS, r=0.72 between SPET EF and echo EF, P<0.0001 for both). In conclusion, quantification of gated SPET of small hearts can be improved by means of a SPET filter with a high cut-off frequency, high system resolution and appropriate zooming. Gated SPET should be attempted not only in patients with small hearts but also in paediatric patients.

Adolescent↗
PubMed2000

Incomplete replication of human parainfluenza virus type 4 in LLC-MK2 cells and in L929 cells.

Human parainfluenza virus type 4A (hPIV-4A) and type 4B (hPIV-4B) were tested for their ability to replicate in the monkey kidney LLC-MK2 cell line (MK2 cells) and the murine L929 cell line (L929 cells). These cells are normally non-permissive for replication of hPIV-4; however, treatment with acetylated trypsin led to virus replication in MK2 cells, but was less effective for L929 cells. Endogenously produced interferon (IFN) played no role in virus replication in L929 cells. Synthesis of virus-specific polypeptides was suppressed in L929 cells. Whereas NP-mRNA and HN-mRNA were detected in MK2 cells, no HN-mRNA was detected in L929 cells. These results indicate that hPIV-4 can infect both MK2 cells and L929 cells. In MK2 cells, when protease exists in the extracellular medium, hPIV-4 exhibits multistep growth. In L929 cells, however, the cause of incomplete replication might be lack of other unknown factors.

Animals↗
PubMed2000

A Japanese propositus with D-- phenotype characterized by the deletion of both the RHCE gene and D1S80 locus situated in chromosome 1p and the existence of a new CE-D-CE hybrid gene.

In a family study of a Japanese propositus with the D-- phenotype, the serological data of her D-- phenotype and those of her parents were discrepant. Gene analysis of the propositus showed a gross deletion of the RHCE gene and a new rearrangement of RHCE to yield the CE-D-CE hybrid. It was demonstrated that the hybrid CE-D-CE gene consisted of exon 1 from the RHCE gene, followed by exons 3 to 7 from the RHD gene and exons 8 to 10 from the RHCE gene. However, whether or not exon 2 of the RHD or the RHCE gene was contained in the CE-D-CE gene remained unclear. Moreover, spacer analysis between both RH genes and the family study suggested that the D-- gene complex from the paternal and maternal sides consisted of only the CE-D-CE hybrid gene and a single RHD gene, respectively. For the purpose of confirming the parent-child relationship, a paternity test using DNA fingerprint and polymerase chain reaction (PCR) analysis at the D1S80 locus were performed. DNA fingerprints with two kinds of DNA minisatellite probes (33.15 and 33.6) confirmed that the parent-child relationship in the D-- propositus was compatible. However, in the present case, at the D1S80 locus, the PCR product derived from the mother was lacking, thereby negating a parent-child relationship. It is probable that the RH genes and D1S80 locus exist in close proximity, because they are situated in chromosomes 1p 34.3-36.1 and 1p 36.1-36.3, respectively. These data suggested that at the stage of gametogenesis, both the RHCE gene and the D1S80 locus from the maternal side may have been deleted, thereby producing the D-- gene complex.

Chimera↗
PubMed2000

Effects of Momordica charantia powder on serum glucose levels and various lipid parameters in rats fed with cholesterol-free and cholesterol-enriched diets.

The effects of dietary bitter melon (Momordica charantia) freeze-dried powder on serum glucose level and lipid parameters of the serum and liver were studied in rats fed diets supplemented with and without cholesterol. Rats were fed the diets for 14 days containing bitter melon freeze-dried powder at the level of 0.5, 1 and 3% without an added dietary cholesterol (experiment I) and those containing bitter melon at the level of 1% with or without 0.5% cholesterol and 0.15% bile acid (experiment II). No adverse effect of dietary bitter melon powder on growth parameters and relative liver weight were noted. Dietary bitter melon resulted in a consistent decrease in serum glucose levels in rats fed cholesterol-free diets, but not in those fed cholesterol-enriched diets, although no dose-response was noted. Addition of cholesterol to the diets as compared to those without added cholesterol caused hypercholesterolemia and fatty liver. Bitter melon had little effect on serum lipid parameters, except for high density lipoprotein (HDL)-cholesterol; HDL-cholesterol levels tended to decrease by dietary cholesterol, while they were consistently elevated by dietary bitter melon both in the presence and absence of dietary cholesterol, indicating an antiatherogenic activity of bitter melon. In addition, bitter melon exhibited a marked reduction in the hepatic total cholesterol and triglyceride levels both in the presence and absence of dietary cholesterol; the reduction of triglyceride levels in the absence of dietary cholesterol was in a dose-dependent manner. These results suggest that bitter melon can be used as a health food.

Animals↗
PubMed2000

Diminished expression of CD59 on activated CD8+ T cells undergoing apoptosis in systemic lupus erythematosus and Sjögren's syndrome.

The present study was undertaken to examine the phenotype of T cells undergoing in vitro apoptosis in patients with autoimmune diseases such as systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (SS). Compared with normal controls, we found diminished expression of CD59 antigen (one of the cell-surface complement-regulatory proteins) on CD8+ T cells, but not on CD4+ T cells, from patients with SLE and SS. Three-colour immunofluorescence analysis revealed that these CD59dim CD8+ T cells were activated T cells, expressing both human leucocyte antigen (HLA)-DR and CD45RO antigens. In addition, these CD59dim CD8+ T cells were more susceptible to in vitro apoptosis than CD59bright CD8+ T cells. In two patients with active lupus, the percentage of CD59dim CD8+ T cells was significantly decreased after steroid therapy. These findings suggest that decreased expression of CD59 antigen on in vivo-activated CD8+ T cells may be correlated with disease activity and may be involved in activation-induced apoptosis in patients with SLE and SS.

Apoptosis↗
PubMed2000

Epidermoid cyst arising from the spermatic cord area.

PURPOSE: We report on an epidermoid cyst arising from the spermatic cord area that was confirmed histologically after local excision. METHODS/RESULTS: Radiologic studies demonstrated a well-encapsulated solid mass in the left inguinal region, which was adjacent to the left spermatic cord. Tumor resection was then performed. Pathological examination revealed a epidermoid cyst lined with keratinized squamous epithelium. CONCLUSION: There was no recurrence observed 5 years after surgery.

Adult↗
PubMed2000

Enantiodifferentiating Z-E photoisomerization of cyclooctene sensitized by DNA and RNA.

DNA and RNA have been shown for the first time to function as chiral photosensitizers in aqueous solution, to effect the enantiodifferentiating photoisomerization of (Z)-cyclooctene (1Z), giving the chiral (E)-isomer in enantiomeric excesses (ee's) of up to 15%. In order to elucidate the effect of nucleotide sequence, enantiodifferentiating photoisomerization of 1Z was also performed using oligo and homopolynucleotides as chiral sensitizer. The -18.8% ee was observed by using d(T)15.d(A)15 as sensitizer, whereas sensitization by the poly(U).poly(A) duplex gave only racemic (E)-cyclooctene. From these results, oligothymidine sequence is essential for efficient enantioselective photoisomerization of 1Z.

Animals↗
PubMed2000

Lethal effect of the expression of a killer gene SMK1 in Saccharomyces cerevisiae.

Expression of the SMK1 gene which encodes the yeast killer toxin SMKT is lethal in Saccharomyces cerevisiae. Effects of deletion and site-directed mutagenesis of SMK1 on the lethality and the secretion of the gene products were examined. Deletion of the interstitial gamma peptide or the C-terminal loop from Ala208 to the C-terminal Asp222 had no effect on the lethality. Those SMK1 products that lacked either the gamma peptide or the C-terminal loop were expressed in the cells but were not secreted into the culture medium, suggesting that these peptides may have a role in secretion or in protein stability. On the other hand, deletion of the signal sequence resulted in complete loss of the lethal activity. Entering the secretory pathway may be critical for the lethality. Further, deletion of the region from the C-terminus to Leu207 resulted in loss of the lethal activity. Leu207 is located at the C-terminus of the central strand of the beta-sheet structure of SMKT and its side chain is thrust into a hydrophobic environment between the beta-sheet and the alpha-helices. The result obtained upon substitutions of Ala, Ser or Glu for Leu207 suggested that the side chain of Leu207 stabilizes the hydrophobic environment that contributes to the overall structure of the SMK1 product.

ATP-Binding Cassette Transporters↗
PubMed2000

Evidence for Na(+) influx via the NtpJ protein of the KtrII K(+) uptake system in Enterococcus hirae.

The ntpJ gene, a cistron located at the tail end of the vacuolar-type Na(+)-ATPase (ntp) operon of Enterococcus hirae, encodes a transporter of the KtrII K(+) uptake system. We found that K(+) accumulation in the ntpJ-disrupted mutant JEM2 was markedly enhanced by addition of valinomycin at pH 10. Studies of the membrane potential (DeltaPsi; inside negative) by 3, 3'-dihexyloxacarbocyanine iodide fluorescence revealed that the DeltaPsi was hyperpolarized at pH 10 in JEM2; the DeltaPsi values of the parent strain ATCC 9790 and JEM2, estimated by determining the equilibrium distribution of K(+) or Rb(+) in the presence of valinomycin, were -118 and -160 mV, respectively. DeltaPsi generation at pH 10 was accomplished by an electrogenic Na(+) efflux via the Na(+)-ATPase, whose levels in the two strains were quite similar. Na(+) uptake driven by an artificially imposed DeltaPsi (inside negative) was missing in JEM2, suggesting that NtpJ mediates Na(+) movement in addition to K(+) movement. Finally, the growth of JEM2 arrested in K(+)-limited high-Na(+) medium at pH 10 was restored by addition of valinomycin. These results suggest that NtpJ mediates electrogenic transport of K(+) as well as Na(+), that it likely mediates K(+) and Na(+) cotransport, and that Na(+) movement via NtpJ is the major Na(+) reentry pathway at high pH values.

Adenosine Triphosphatases↗
PubMed2000

Tamoxifen inhibits lipoprotein activity: in vivo and in vitro studies.

Tamoxifen, a nonsteroidal antiestrogenic antitumor agent, has weak estrogen-like effects on lipid metabolism, however, the mechanism remains unknown. We previously reported that tamoxifen decreases the activity of lipoprotein lipase (LPL), a key enzyme in triglyceride metabolism, in patients with breast cancer. This study evaluated the effect of tamoxifen on LPL activity in vitro and in vivo. In experiment 1, total cholesterol, triglyceride, adipose tissue weight, and LPL activity of post-heparin plasma were measured in ovariectomized female rats with and without tamoxifen treatment. In experiment 2, purified very-low-density lipoprotein (VLDL) and purified LPL were incubated with and without tamoxifen or estrogen, and the triglycerides in VLDL were measured using an enzymatic method. In experiment 1, total cholesterol and adipose tissue weight decreased significantly in tamoxifen-treated rats (p < 0.001 and p < 0.01, respectively). Triglyceride measurements were not significantly different between the two groups, however, the LPL activity was lower in tamoxifen-treated rats (p < 0.005). In experiment 2, triglycerides in VLDL were significantly higher after VLDL and LPL were incubated with tamoxifen and estrogen (p < 0.005). We concluded that tamoxifen inhibits the hydrolytic activity of LPL in vivo and in vitro. This mechanism may explain the elevated serum triglyceride levels in some patients treated with tamoxifen.

Animals↗
PubMed2000

Effects of photoperiod and ambient temperature on the gonadotropin-releasing hormone neuronal system in the gray hamster, Tscherskia triton.

In seasonal breeders like the hamster, gonadal function depends on the photoperiod. The present study examined the effects of different photoperiods and ambient temperatures on the gonadotropin-releasing hormone (GnRH) neuronal system in male gray hamsters, Tscherskia triton. Hamsters were kept from birth under a long-day (LD: 16 h light and 8 h dark) photoperiod and at 23 degrees C until the experiment began. The animals were then kept for 30 days under different photoperiods and ambient temperatures. After autopsy, immunocytochemical and semiquantitative reverse transcription-polymerase chain reaction analyses were performed on the hamster forebrain. Exposure to a short-day (SD: 8 h light and 16 h dark) photoperiod at 23 degrees C induced a functional decline in the GnRH neuronal system (increased neuron number and immunoreactivity, and reduced cell size). LD with low ambient temperature (7 degrees C) did not influence the GnRH neuronal system. In contrast, SD with low ambient temperature enhanced the SD-induced functional decline in GnRH neurons. Changes in immunoreactivity of GnRH fibers in the median eminence, their release site, were also similar to those in neuronal perikarya. Significant differences in GnRH gene expression were detected in the SD only group and the SD with low ambient temperature group. However, no differences were detected between the two groups. These findings suggest that low ambient temperature enhanced the SD-induced decline in GnRH release from nerve terminals, but was not a crucial factor in the synthesis of this decapeptide.

Animals↗