Biomedical subjects

M Kawamura

Publications and source records attributed to M Kawamura.

At least 451 records · Page 25Linked to original sources

PubMed1992

[Effect of Ca(2+)-channel antagonists on the corticoidogenesis in primary cultured bovine adrenocortical cells].

We investigated the effect of Ca(2+)-channel antagonists, Nicardipine(N), Verapamil(V) and Flunarizine(F), on the corticoidogenesis(CG) in primary cultured bovine adrenocortical cells. To examine the effect on receptor operated Ca(2+)-channel(ROC) and voltage operated Ca(2+)-channel(VOC), involved in corticoid synthesis, adrenocorticotropic hormone(ACTH) and high-K+ were used respectively. With or without the antagonists, cells were incubated at 37 degrees C for 1h in the presence of ACTH (100pM) or K+ (30mM). Corticoid was measured fluorometrically using cortisol as the standard. N and V inhibited not only ACTH-induced CG, but high K(+)-induced CG in a concentration-dependent manner. However, F inhibited only high K(+)-induced CG, and did not affect ACTH-induced CG. These inhibitions were observed at the low micromolar concentrations (below 40 microM) of the antagonists. In the regulation of corticoid synthesis, we indicate that F has an inhibitory effect on VOC without ROC; on the other hand, N and V inhibit both ROC and VOC.

Adrenal Cortex↗

PubMed1992

Secretion of autocrine growth-promoting activity by renal-carcinoma cells treated with 5-fluorouracil.

A study was made of the auto-proliferative activity of human renal-carcinoma cells in the supernatant from a carcinoma-cell culture in serum-free medium to which an anticancer agent had been added (5-FU). The human renal-cancer cells used in this study were of 3 strains: ACHN, VMRC-RCW and NT. When each line was cultured in medium containing no 5-FU, the supernatant showed almost no activity for stimulating DNA synthesis. However, when the line was cultured in the presence of 5-FU, the supernatant showed autocrine growth-promoting activity which strongly stimulated DNA synthesis of 3 renal-cancer cell lines in a dose-dependent manner. Activity could be detected in a 4- to 6-kDa fraction by gel filtration. This fraction increased the DNA-synthesis-promoting activity of epidermal growth factor, transforming growth factor-beta, basic fibroblast growth factor and insulin, and was acid- and heat-stable. It was also stable against pepsin and dithiothreitol. DNA synthesis in BALB/c 3T3, adult rat hepatocytes and rabbit renal tubular cells was not affected by this fraction which was thus considered not to affect non-cancerous cells. Renal-cell carcinoma responds poorly to anticancer agents, and the autocrine activity of the fraction may possibly be a factor accounting for this resistance.

3T3 Cells↗

PubMed1992

Anticardiolipin antibodies in NZW x BXSB F1 mice. A model of antiphospholipid syndrome.

NZW x BXSB F1 (W/B F1) male mice develop systemic lupus-like disease, and several autoantibodies, circulating immune complexes, and lupus nephritis become apparent. The abnormally high incidence of degenerative coronary vascular disease with myocardial infarction and thrombocytopenia due to the presence of both platelet-associated antibodies and circulating antiplatelet antibodies in this animal has been reported. We found that W/B F1 male mice produced autoantibodies against cardiolipin (aCL) and that the titer of aCL increases with age. aCL from W/B F1 male mice were mainly IgG and binding activity to cardiolipin was aCL-cofactor (beta 2-glycoprotein I (beta 2-GPI)) dependent. We developed monoclonal aCL from these animals and examined specificity of the autoantibodies. All the mAb used reacted with the negatively charged phospholipids, cardiolipin, phosphatidylserine, and phosphatidylinositol, and some reacted with platelets and DNA. The addition of human or mouse beta 2-GPI enhanced the titer for monoclonal aCL from the W/B F1 mice. From the results of competitive inhibition enzyme immunoassay with monoclonal aCL and purified beta 2-GPI, aCL from the W/B F1 mice recognized the complex of CL and beta 2-GPI. The W/B F1 male mouse may be an appropriate model for use in studies on the pathologic significance of aCL in patients with antiphospholipid syndrome.

Animals↗

PubMed1992

[A case with delayed-onset radiation pneumonitis suspected to be induced by oral etoposide].

Radiation pneumonitis usually occurs within 1-3 months after the completion of radiation therapy. A 63-year-old male with primary lung cancer treated by radiation therapy developed radiation pneumonitis 5 months after the completion of radiation therapy. He received 60 Gy to the lung tumor in a conventional fractionation schedule, and then two courses of intravenous chemotherapy using cis-diamine-dichloroplatinum (II) (110-140 mg) and etoposide (140-175 mg). Oral etoposide was initiated for bone metastases on the 104th day after the completion of radiation therapy at a daily dose of 20 mg, to a total dose of 1075 mg. He complained of fever and exertional dyspnea 5 months after the completion of radiation therapy. Chest radiography showed homogeneous infiltrates in the irradiated lung. These clinical signs and symptoms were refractory to antibiotic therapy, but steroid therapy resulted in marked improvement. The development of radiation pneumonitis was suspected to be induced by oral etoposide, which was given before the onset of radiation pneumonitis. These data suggest that etoposide induces a recall phenomenon, as has been demonstrated with such drugs as adriamycin and actinomycin-D.

Administration, Oral↗

PubMed1992

[Temperature distribution and geometry of the electrodes in RF interstitial hyperthermia using circular and interstitial electrodes].

To evaluate the feasibility of clinical application of a newly developed interstitial hyperthermia system, which consists of an 8 MHz radiofrequency generator, interstitial needle electrodes, and a superficial circular electrode, we conducted preclinical experiments using an agar phantom and VX-2 carcinoma in the rabbit. In the experiment with an agar phantom, four 4 cm needle electrodes were placed in a square array at intervals of 1.0, 1.5, and 2.0 cm. Thermography demonstrated homogeneous temperature distribution at electrode intervals of 1.0 and 1.5 cm, but hot spots around the electrodes at an interval of 2.0 cm. When electrode deviation was less than 8 degrees from the parallel plane, no temperature deviation was observed. Using two 2 cm electrodes and two 4 cm electrodes in square array, thermography demonstrated a homogeneous temperature distribution in the area surrounded by the electrodes. Even if the electrodes were located at the periphery of the agar phantom, a homogeneous temperature distribution was obtained in the area surrounded by the electrodes. Using four 4 cm electrodes at intervals of 1.5 cm in VX-2 carcinoma in the rabbit, ideal heating was obtained: 42 degrees C at the periphery of the tumor and 43 degrees C at the center. These data suggest that the newly developed interstitial hyperthermia apparatus provides homogeneous heat distribution at electrode intervals of 1.5 cm or less and can be used in a Phase I study for deep-seated or superficial tumors.

Animals↗

PubMed1992

[Radiation therapy for patients with obstructive jaundice caused by carcinoma of the extrahepatic biliary system].

From February 1980 through September 1990, 92 patients with obstructive jaundice resulting from biliary tract cancer registered at Shikoku Cancer Center Hospital or Ehime University Hospital. Radiation therapy (RT) was used to treat 38 of these patients (30 with carcinoma of the extrahepatic bile duct, excluding ampulla of Vater, and eight patients with carcinoma of the gallbladder). Of 38 patients, 11 underwent intraoperative radiation therapy (IORT), and 27 were treated by external radiation therapy (ERT) alone. In contrast, 54 patients (39 with carcinoma of the extrahepatic bile duct and eight with carcinoma of the gallbladder) were not treated by RT. All jaundiced patients received external and/or internal biliary drainage of some kind. Among patients undergoing biliary drainage with a catheter, 21 patients who underwent RT (four with IORT) survived significantly longer than 19 patients who did not (generalized Wilcoxon test: p less than 0.05). There were no significant differences in survival between 7 patients with recanalization and 11 patients with no recanalization. Concerning the survival of laparotomized patients, excluding those with complete resection or perioperative death, eight patients treated with postoperative ERT survived longer than 12 patients who did not have postoperative ERT (not significantly). Eleven patients underwent IORT. A patient with unresectable carcinoma of the hilar bile duct survived 2 years and 3 months after a combination treatment of ERT and IOTR. In four of eight autopsied patients, radiation effects of Grade II were observed (Oboshi and Shimosato's evaluation system for the histological effects of radiation therapy). Our experience suggests that RT is effective in patients with obstructive jaundice caused by carcinoma of the biliary system.

Adenocarcinoma↗

PubMed1992

A newly identified null allelic mutation in the human lipoprotein lipase (LPL) gene of a compound heterozygote with familial LPL deficiency.

In a Japanese patient with familial LPL deficiency, a new null allelic mutation, one base pair deletion at nucleotide position 916 was identified in exon 5 of one allele. In exon 3 of the other allele, we found the same nonsense mutation as we described previously in other Japanese kindreds. For the deletional mutant allele, we developed a simple detection method and constructed the DNA haplotype.

Alleles↗

PubMed1992

The structure of glutaraldehyde in aqueous solution determined by ultraviolet absorption and light scattering.

The structure of glutaraldehyde (GA) in aqueous solutions has been the subject of much debate. Since there were fundamental problems in the experiments in the preceding studies, in this article, the structure of GA was investigated with uv absorption and light scattering to avoid those problems. It was discovered that 70% glutaraldehyde solution contains a large quantity of polymeric species with cyclic hemiacetal structure. On dilution, the polymerized glutaraldehyde slowly converted to monomers. In dilute solution, glutaraldehyde is almost monomeric at pH 3-8, the major portion taking the cyclic hemiacetal structure. The structure of GA in 20% solution is similar to that in more dilute solution. alpha, beta-Unsaturated structure does not exist in aqueous solution regardless of the concentration of glutaraldehyde.

Glutaral↗

PubMed1992

Assembly of a hybrid from the alpha subunit of Na+/K(+)-ATPase and the beta subunit of H+/K(+)-ATPase.

Messenger RNA for the alpha subunit of Torpedo californica Na+/K(+)-ATPase was injected into Xenopus oocytes together with that of the beta subunit of rabbit H+/K(+)-ATPase. The Na+/K(+)-ATPase alpha subunit was assembled in the microsomal membranes with the H+/K(+)-ATPase beta subunit, and became resistant to trypsin. These results suggest that the H+/K(+)-ATPase beta subunit facilitates the stable assembly of the Na+/K(+)-ATPase alpha subunit in microsomes.

Adenosine Triphosphatases↗

PubMed1992

[Results of radiation therapy for squamous cell carcinoma of the uterine cervix using high dose-rate intracavitary irradiation].

We retrospectively analyzed 216 previously untreated patients with cervical cancer treated by high dose-rate intracavitary irradiation between 1978 and 1986. Cumulative 5-year survivals in stage Ib, IIa, IIb, IIIa, IIIb and IVa were 72.3%, 88.9%, 68.9%, 75.0%, 64.0% and 16.7%, respectively. Cause-specific 5-year survivals in stage Ib, IIa, IIb, IIIa, IIIb and IVa were 93.3%, 88.9%, 74.7%, 75.0%, 68.9%, and 18.8%, respectively. Recurrences outside the pelvis in stage IIb and IIIb (14.9% and 24.0%) were more common than loco-regional recurrences (10.3% and 12.0%). However, loco-regional recurrences (50%) were most frequent in stage IVa. Thirteen patients (6.0%) required surgical management for intestinal complications (severe). Six patients (2.7%) died due to intestinal complications (fatal). These fatal and severe complications were closely correlated with the dose of external radiation. These data suggest that intracavitary irradiation using a high dose-rate system is useful for the treatment of uterine cancer; however, further efforts to reduce intestinal complications by lowering the dose of external radiation will be necessary. It is also suggested that a combined modality, such as chemotherapy, is necessary for controlling metastases outside the pelvis in stage IIb and IIIb, and for local control in stage IVa.

Adult↗

PubMed1992

Genetic analysis of a Japanese family with normotriglyceridemic abetalipoproteinemia indicates a lack of linkage to the apolipoprotein B gene.

Normotriglyceridemic abetalipoproteinemia is a rare familial disorder characterized by an isolated deficiency of apoB-100. We have previously reported a patient with this disease, who had normal apoB-48 but no apoB-100. To elucidate the genetic abnormalities in this family, we studied the linkage of apoB gene using three genetic markers. The proband and her affected brother showed completely different apoB gene alleles, suggesting that the apoB gene itself is not related to this disorder in this family. By contrast, an American case had a point substitution in the apoB gene generating an in-frame stop codon. These results indicate that this disorder can be caused by defect(s) of either an apoB gene or other genes.

Abetalipoproteinemia↗

PubMed1992

Transforming and c-fos promoter/enhancer-stimulating activities of a stimulatory GDP/GTP exchange protein for small GTP-binding proteins.

smg GDP dissociation stimulator (GDS) is a stimulatory GDP/GTP exchange protein for a group of ras p21-like small GTP-binding proteins (G proteins) including c-Ki-ras p21, smg p21A, smg p21B, and rhoA p21. smg GDS converts the GDP-bound inactive form to the GTP-bound active form of each small G protein by stimulating their GDP/GTP exchange reaction in a cell-free system. The point-mutated c-Ki-ras p21 (c-Ki-rasval12 p21) is known to strongly transform NIH/3T3 cells and to markedly stimulate the c-fos promoter/enhancer in this cell line, whereas the normal c-Ki-ras p21 is weak in these activities. In the present study, we examined the effect of smg GDS on these activities to explore its physiological function. Overexpression of both smg GDS and c-Ki-ras p21 strongly transformed NIH/3T3 cells, whereas overexpression of either smg GDS or c-Ki-ras p21 alone weakly transformed the cells. Furthermore, overexpression of both smg GDS and c-Ki-ras p21 markedly stimulated the c-fos promoter/enhancer in NIH/3T3 cells, whereas overexpression of either smg GDS or c-Ki-ras p21 alone weakly stimulated it. These results indicate that smg GDS transforms NIH/3T3 cells and stimulates the c-fos promoter/enhancer in this cell line in cooperation with c-Ki-ras p21.

3T3 Cells↗

PubMed1992

Time-dependent changes of collagen cross-links and their precursors in the culture of osteogenic cells.

The early stage of cross-link formation in bone collagen was studied in a cell culture system. An osteogenic cell line that produces and accumulates a remarkably high amount of collagen, and that eventually forms bone-like structures, was used in this study for its time-dependent development of reducible cross-links. It was found that precursors of the cross-link, dehydro-dihydroxynorleucine and dehydro-hydroxynorleucine became detectable as soon as the cells attained a confluent state. They showed maximal amounts at days 3-5 after confluence, but substantially disappeared at day 10 after confluence. In contrast, two characteristic cross-links of bone collagen, dehydro-dihydroxylysinorleucine (dehydro-DHLNL) and dehydro-hydroxylysinorleucine (dehydro-HLNL), which were present in trace amounts at the stage of cell confluence, gradually increased in amount and reached a plateau at day 10, just when their precursors disappeared. Thus, it was found that there was a time lag of about a week between the maximal formations of precursors and cross-links of bone collagen in this system. The significance of this time lag was interpreted in terms of the minimum essential accumulation of collagen for the precursor-product transition. The ratio of dehydro-DHLNL to dehydro-HLNL was as low as 0.7 at day 3 after confluency, increased to 4.2 at day 20, the period just before mineralization began, and decreased thereafter, suggesting a qualitative change in bone collagen associated with mineralization.

Animals↗

PubMed1992

An osteonectin-like protein in the matrix of cultured osteogenic cell-line MC3T3-E1, which is associated with calcification.

Time-dependent changes of the [3H]-proline-labeled noncollagenous proteins synthesized by the osteogenic cell-line MC3T3-E1 were analyzed over a range starting from cell confluency to 13 days after confluency during which time cells formed a bone-like structure. It was found that the 40 kDa protein on SDS-polyacrylamide gel (SDS-PAGE) remarkably increased in the cell-matrix layer at about 9 days after cell confluence, just before calcification. This protein was highly purified and was found to contain high amounts of glutamic acid, glycine, and serine. An internal amino acid sequence of this protein was revealed to be K-X-M-A-P-E-E-X-P, which showed homology with the sequence of the EF-hand domain in osteonectin/SPARC (secreted protein, acidic, and rich in cysteine). This protein co-migrated with collagen in gel filtration, and ion-exchange chromatography. Furthermore, it showed high affinity to type I collagen.

Amino Acid Sequence↗

PubMed1992

Biological characterization of human immunodeficiency virus type 1 and type 2 mutants in human peripheral blood mononuclear cells.

Mutants of human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2), which have been shown to be infectious in established cell lines, were tested for ability to replicate and induce syncytium formation in human peripheral blood mononuclear cells (PBMC). The vpu mutant of HIV-1 showed depressed kinetics of replication in an established T cell line, as reported previously, but in PBMC, its replication was similar to that of the wild type virus. The vpx gene of HIV-2 was required for efficient virus propagation in PBMC, but not in an established T cell line, as previously reported. However, the growth rates of the vpx mutant in PBMC preparations from two individuals were different. The results of experiments on infection of PBMC with the vif and vpr mutants of HIV-1 and HIV-2 were essentially consistent with previous results of infection of established T cell lines. No negative effect of the nef gene products of HIV-1 and HIV-2 was observed. The abilities of the wild type virus and the mutants of HIV-1 to induce syncytium formation in both PBMC and established cell lines were similar. In contrast, neither the wild type nor any of the mutants of HIV-2 induced syncytium formation in PBMC. These results suggest that the functions of some genes can be detected only in mixed populations or primary cells such as PBMC. Studies on the roles of these genes in PBMC may provide a better understanding of their functions in vivo.

Cells, Cultured↗

PubMed1992

Serum fluoride concentration after sevoflurane anesthesia in ethanol treated rats: special reference to cytochrome P-450 in the liver.

The relationship between serum concentration of inorganic fluoride (F(-)) and cytochrome P-450 content after sevoflurane anesthesia was investigated in ethanol treated rats. Twenty male Wistar rats were randomly divided into 2 isocaloric diet groups of 10 rats each: one group receiving a standard diet and the other an ethanol diet. After 28 days on the diets the animals were administered 2.5% sevoflurane for 2 hr with 30% oxygen and 70% nitrous oxide. Cytochrome P-450 and cytochrome b(5) were induced by the ethanol diet. In the ethanol diet group serum concentration of F(-) was significantly higher than that of the standard diet group after sevoflurane anesthesia. These results suggest that cytochrome P-450 and b(5), which were induced by ethanol, enhanced sevoflurane defluorination.

Journal Article↗

PubMed1992

Macrophage colony stimulating factor prevents the progression of atherosclerosis in Watanabe heritable hyperlipidemic rabbits.

The early atherosclerotic lesion is characterized by the presence of macrophage-derived foam cells. Macrophage colony stimulating factor (M-CSF) specifically stimulates the functions of the monocyte-macrophages. To elucidate the effects of M-CSF in the atherogenic process in vivo, we administered human recombinant M-CSF into Watanabe heritable hyperlipidemic (WHHL) rabbits, an animal model for familial hypercholesterolemia. Three hundred micrograms of M-CSF were intravenously injected into WHHL rabbits aged 2.5 months, three times a week for 8.5 months. After the M-CSF treatment, we found very retarded progression of atherosclerosis. The accumulation of cholesterol ester was remarkably decreased in the aortae of M-CSF-treated animals (0.60 +/- 0.32 mg/g tissue), as compared to those of controls (4.32 +/- 0.61 mg/g tissue). Furthermore, the percentage of the surface area of the aorta with macroscopic plaque in animals treated with M-CSF was 14.3 +/- 6.2%, much less than that in controls receiving saline injection (38.8 +/- 8.0%). Thus, M-CSF definitely prevented the progression of atherosclerosis in WHHL rabbits by influencing macrophage functions.

Animals↗

PubMed1992

Isolation and characterization of a highly divergent HIV-2[GH-2]: generation of an infectious molecular clone and functional analysis of its rev-responsive element in response to primate retrovirus transactivators (Rev and Rex).

A highly divergent HIV-2 designated as HIV-2[GH-2] was obtained from an AIDS-related complex (ARC) patient in Ghana. A full-length molecular clone of this isolate was obtained and a biologically active clone was constructed. Its restriction pattern differed from that of prototype HIV-2[GH-1] in 25 of 35 restriction sites, but was strikingly similar to a previously characterized HIV-2 isolate from a Ghanaian (HIV-2ALT). The conserved integrase region (288-bp fragment) previously displayed 95% identity with that of ALT but 17-20% divergence from the HIV-2 prototype member, and a new distinct subgroup (HIV-2b) of HIV-2 consisting of GH-2 and ALT was postulated (Miura et al. 1991.) These isolates, however, were biologically distinguishable from each other by its replication capacity in a monocyte line, U937, in which GH-2 could not grow but ALT grew well. In addition, the nucleotide sequence of the LTR of this new isolate displays 21% divergence from that of prototype HIV-2[GH-1], but the core enhancer, Sp1 binding sites and TATA box were conserved. Although the 3' half of the env gene sequence which is deleted in HIV-2ALT clone showed 27% diversity from the prototype, functional differences in the rev-responsive element were not observed.

Cloning, Molecular↗