Search PubMed⌕ Search

Biomedical subjects

K Morimoto

Publications and source records attributed to K Morimoto.

At least 379 records · Page 21Linked to original sources
PubMed1993

[The effect of oxytocin stimulation on PGE2, 6keto PGF1 alpha production in human myometrial monolayer culture].

In order to clarify the mechanism by which oxytocin induces the generation of prostaglandin (PG) in human myometrial smooth muscle cell, we determined the concentration of PGE2 and 6ketoPGF1 alpha in the culture supernatant of human myometrial monolayer cells stimulated by oxytocin. PGE2 and 6ketoPGF1 alpha demonstrated a biphasic increasing curve when oxytocin was added. The first increase, phase 1, was a transient phenomenon with a peak at 20 seconds whereas the second increase, phase 2, was a continuous phenomenon starting at 120 seconds. Moreover, phase 1 was significantly inhibited by the DG lipase inhibitor, RHC80267. Phase 2 was significantly inhibited by the PLA2 inhibitor, Mepacrine. Phase 1 and 2 were dose dependent in the range 10(-10) to 10(-6) M. PG production at rest during which 6ketoPGF1 alpha was higher than PGE2, was reversed by oxytocin stimulation. These results suggest that oxytocin stimulation would actuate biphasic PG production, and this mechanism would probably regulate the myometrial construction in labor-pain initiation.

Calcium↗
PubMed1993

[Prospective randomized study on effect of duration of antimicrobial prophylaxis for mastectomy].

A prospective randomized trial was done to study effects of the duration of ofloxacin (OFLX) administration for prophylaxis against mastectomy wound infections. One hundred and seventeen women who were hospitalized, during periods between June 1990 and September 1992 were considered for enrollment in this study. Selected patients were treated with 600 mg of OFLX daily in 3 divided doses starting the day before surgery. One group was treated for 5 days and the other was treated for 10 days. A hundred and ten patients were found eligible to complete the study and 58 patients were assigned to the 5-day group and 52 patients were assigned to the 10-day group by the random-envelope method. Nine episodes of infections occurred among the patients in the 5-day group and 12 episodes of infections occurred among those in the 10-day group. The mean time until onset of infection was not significantly different between the 2 groups (12 versus 8 days). The number of strains isolated from the drainage tube when removed was highly correlated with occurrences of infections, and the number of strains isolated from infected wounds was also highly correlated with the need to use a different antibiotic. By multiple regression analysis, age was the only significant factor identified for wound infection. The duration of OFLX administration had no significant effect on the development of wound infections. Prolonged prophylactic use of this drug for mastectomy did not reduce the incidence of postoperative infections in this study.

Female↗
PubMed1993

[The effect of oxytocin on production of free fatty acid in primary human uterine myometrial cell culture].

Oxytocin(OT) is considered to have several activities besides strongly inducing myometrial contraction by activating phosphatidilinositol-specific phospholipase C(PI-PLC). These include reconstructing the phospholipid constituents of the cell membrane and activating a variety of fatty acid producing systems. On the other hand, pregnancy-related steroid hormones which are produced by the fetus, placenta and mother are considered to be closely involved in the maintenance of pregnancy and the initiation of labor. In the present study with cultured myometrial cells, we examined what effect these steroid hormones might exert on the intramyometrial production of fatty acid by OT. Our results confirmed bi-phasic production of arachidonic acid(AA), linoleic acid(LA), palmitic acid(PA), and stearic acid(SA) by OT. Phase 1 was an increasing but transient phenomenon having its peak at 30 sec. It is considered to be derived from phosphatidylinositol bis-phosphate. Phase 2 was a persistent and increasing phenomenon which was initiated after 120 sec. It is considered to be mediated by Ca-dependent phospholipase. We also studied the effect of steroid hormones on the production of fatty acid. For AA, LA, and PA, we confirmed that dehydroepiandrosterone sulfate(DHAS) shortened the time taken in reaching the peak of Phase 1 to half of that of the control, and progesterone(P) extended the time 2-3 fold. These findings suggest that DHAS, P and F might modify the human myometrial construction mechanism as a factor which regulates the quantity and velocity of fatty acid production.

Arachidonic Acid↗
PubMed1993

[Effects of steroid hormones on change in [Ca2+]i following oxytocin stimulation in cultured human myometrial cells, and on myometrial oxytocin receptor].

It is considered that steroid hormones, the concentrations of which vary during pregnancy, play an important role in the initiation of delivery. In the present study, we measured intracellular Ca2+ ([Ca2+]i) change following oxytocin stimulation in cultured human myometrial cells with fura-2, a fluorescent Ca2+ indicator. We also studied the effect of the steroid hormones on changes in [Ca2+]i due to oxytocin stimulation. When the [Ca2+]i change due to 10(-6) M oxytocin reached 100%, the addition of 10(-6) M DHAS (dehydroepiandrosterone sulfate) just before the stimulation raised the [Ca2+]i level to 207%, whereas that of 10(-6) M progesterone dropped to 64%. Moreover DHAS accelerated the speed of increase until the maximum response of [Ca2+]i, while progesterone decelerated it. In another study, human myometrial plasma membrane was solubilized in 7.5mM CHAPSO solution and applied to a binding study. Oxytocin receptors of two different molecular weights, namely 350kD(OTR-1) and 39kD(OTR-2), were extracted from solubilized plasma membrane by employing a gel filtration column. Binding assays were performed for OTR-1 and OTR-2 in the presence of DHAS and progesterone (10(-5) M). The results showed that DHAS enhanced the binding affinity of the receptors, whereas progesterone reduced the maximum binding capacity. It is therefore considered that the steroid hormones added just before oxytocin stimulation might act on receptor levels and modify intracellular Ca2+ response over short periods.

Calcium↗
PubMed1993

[The effect of steroid hormone on oxytocin receptor expression in primary human uterine myometrial cell culture].

In the present study, we have examined the steroid hormone effect on oxytocin receptor (OTR) expression in human myometrial monolayer culture. The myometrial cells were cultured for 24-72 hours in serum-free media with various concentrations of steroid hormones. The plasma membrane of the cultured cells was then collected. The 125I-oxytocin(OT) was employed for a binding assay and the mean binding and dissociation constant were evaluated by Scatchard analysis. 1. The OT binding values in the presence of estradiol free, 10(-8) M, and 10(-7) M at 72 hours were 19.85, 28.12, and 36.20pM/mg protein, respectively. 2. The OT binding values in the presence of estradiol (10(-7) M) at 24, 48, and 72 hours were 17.85, 23.72, and 36.20pM/mg protein, respectively. 3. Dehydroepiandrosterone sulfate (10(-5) M) exerted almost no effect on the OTR expression by estradiol (10(-7) M). Cortisol (10(-5) M) decreased the amount of OTR expressed by estradiol. 4. The changes in OTR expression caused by estradiol (10(-7) M) were inhibited according to the concentration by progesterone. The concentration of progesterone at which OT binding was reduced 50% was 2.7 x 10(-6) M (E/P ratio = 0.037). These results suggested that estradiol increased the amount of OTR discovered in human myometrial cells in a time and concentration dependent manner, while progesterone inhibited the changes in OTR expression by estradiol in a concentration dependent manner. Thus, it was indicated that the changes in the E/P ratio during pregnancy which regulate the OTR expression control the myometrial contraction.

Cell Membrane↗
PubMed1993

[A case report of graft-versus-host disease caused by using stored blood after aortic valve replacement].

A 61-year-old man underwent aortic valve replacement and received transfusion of 8 units of stored blood. Erythema appeared on the entire body the 12th day after operation, and was followed by high fever, elevation of liver enzymes, progressive pancytopenia, aplastic bone marrow and diarrhea. He died due to septic shock on the 19th postoperative day. Skin biopsy showed the typical features observed in graft-versus-host disease (GVHD). Based on the clinical course, skin and bone marrow biopsy, we diagnosed as post-transfusion GVHD. Therefore, even when stored blood or stored red blood cells are used, these should be irradiated and transfused through the leukocyte removal filter.

Aortic Valve↗
PubMed1992

Transcriptional activation of c-fos and c-jun protooncogenes by serum growth factors in osteoblast-like MC3T3-E1 cells.

The present study was undertaken to clarify the relationship between c-fos and c-jun protooncogene expression and the differentiation and/or proliferation of osteoblasts, using osteoblast-like MC3T3-E1 (E1) cells. c-fos mRNA was barely detectable, whereas c-jun mRNA was constitutively expressed in E1 cells after serum deprivation for 24-72 h. When serum was added, a rapid and transient induction of c-fos and c-jun mRNAs was observed. The c-fos and c-jun mRNAs reached peak levels at 30 minutes, with a rapid disappearance of c-fos mRNA within 3 h and a much slower decrease in c-jun mRNA. The addition of serum together with cycloheximide, an inhibitor of protein synthesis, resulted in the superinduction of both c-fos and c-jun mRNAs. Among various growth factors, PDGF, EGF, and bFGF mimicked the serum effect, whereas IGF-I and TGF-beta failed to induce c-fos and c-jun mRNA. The effects of PDGF, EGF, and bFGF were completely abolished by pretreatment with actinomycin D, an inhibitor of RNA synthesis, suggesting a transcriptional mechanism. Nuclear runoff experiments showed that the transcription rate of c-fos and c-jun protooncogenes was increased by serum and growth factors. The effects of PDGF, EGF, and bFGF were inhibited by H-7 or staurosporine, inhibitors of protein kinase C (PKC), but not by HA1004 with a much weaker inhibitory activity, suggesting the involvement of PKC for the activation of the protooncogenes.(ABSTRACT TRUNCATED AT 250 WORDS)

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Effects of running training on the blood glucose and lactate in rats during rest and swimming.

The purpose of this study was to examine the effect of physical training on the concentrations of glucose and lactate in the blood of rats during rest and after an acute bout of exercise. We used the following types and periods of training; (i) swimming for 4 weeks, (ii) running for 4 weeks, and (iii) running for 10 weeks. The results clearly show that the resting levels of blood glucose was significantly lower in groups trained by either swimming or running than untrained groups. In addition, after the acute exercise of swimming, animals trained by either running or swimming showed a lower increase in the blood lactate than untrained animals. Furthermore, the increases in the blood glucose after swimming were significantly lower in the group trained by swimming for 4 weeks and by running for 10 weeks than in untrained groups. These results suggest that after physical training by running, animals show an adaptation in the changes in the blood glucose and the blood lactate that are induced by a different type of physical stress, swimming.

Adaptation, Physiological↗
PubMed1992

Syncytium formation is induced in the murine neuroblastoma cell cultures which produce pathogenic type G proteins of the rabies virus.

We investigated comparatively the interactions of host cells with two types of rabies virus G protein, an avirulent type G (Gln) and a virulent type G (Arg) protein, having glutamine and arginine at position 333, respectively. For this purpose, we established four types of cell lines (referred to as G(Gln)-NA, G(Arg)-NA, G(Gln)-BHK, and G(Arg)-BHK cells, respectively) by transfecting either the G(Gln)-cDNA or G(Arg)-cDNA into two kinds of cells, murine neuroblastoma C1300 (clone NA) and nonneuronal BHK-21. Both G(Gln)-NA and G(Arg)-NA cells produced G proteins when they were treated with 5 mM sodium butyrate, but only G(Arg)-NA cells formed syncytia at the neutral pH, which was suppressed by anti-G antiserum. The sodium butyrate-treated G(Arg)-NA cells fused also with sodium butyrate-treated NA cells under coculture conditions, but neither with untreated NA cells nor with BHK-21 cells. On the other hand, both G(Gln)-BHK and G(Arg)-BHK cells constitutively produced G proteins, but no syncytium was produced at the neutral pH. G(Arg)-BHK cells, however, formed syncytia with the sodium butyrate-treated NA cells when they were cocultured. These results suggest that only G(Arg) has a potential ability to produce syncytia of NA cells regardless of cell types by which G(Arg) protein was produced and also suggest that a certain cellular factor(s) is required for the syncytium formation, the factor(s) which is lacking in BHK-21 and untreated NA cells but is produced by the sodium butyrate-treated NA cells.

Amino Acid Sequence↗
PubMed1992

Healthy lifestyles are associated with higher natural killer cell activity.

BACKGROUND: To investigate the association of individual lifestyle with immune response against tumors, we assayed peripheral blood lymphocytes of 62 healthy males ranging in age from 30 to 60 years for natural killer (NK) cell activity, which is the first line of defense against tumors, and for frequencies of NK cell subsets. METHODS: The NK cell activity was determined by 51Cr release assay, and NK cell subsets were counted using surface antigens (CD16, CD57) which recognize NK cell subgroups with different cytolytic potentials. Subjects were classified into groups reporting good, moderate, and poor lifestyles according to their responses on a questionnaire regarding eight health practices (tobacco smoking, alcohol consumption, hours of sleep, physical exercise, eating breakfast, balanced nutrition, hours of work habits, and mental stress). RESULTS: Individuals reporting good lifestyle habits were found to have the highest NK cell activity and it was significantly higher than the NK cell activity in those reporting poor lifestyle habits. Those reporting good health practices regarding smoking and physical exercise showed significantly higher NK cell activity at an effector-to-target-cell ratio of 40:1. CONCLUSIONS: The higher NK cell activity among individuals reporting good lifestyle practices may reflect an increase in the cytolytic potential of NK cell activity within the CD16+, CD57- subset.

Adult↗
PubMed1992

Single-step purification of F(ab')2 fragments of mouse monoclonal antibodies (immunoglobulins G1) by hydrophobic interaction high performance liquid chromatography using TSKgel Phenyl-5PW.

Hydrophobic interaction high performance liquid chromatography (HPLC) using TSKgel Phenyl-5PW was applicable to single-step purification of F(ab')2 fragments from pepsin digests of mouse monoclonal antibodies of IgG1 class. The digests were applied to the gel equilibrated with phosphate-buffered saline containing 1 M ammonium sulfate. F(ab')2 fragments were adsorbed onto the gel using the same buffer, and eluted by reducing the ammonium sulfate concentration to 0 M. The fraction containing F(ab')2 fragments was homogeneous (purity: higher than 98%) by both sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration HPLC. The recovery of the antigen binding site was 42-58%. The cycle time of the Phenyl-5PW HPLC was 45 min, and F(ab')2 of up to 2200 mg was purified in a cycle. This method could be useful especially for large scale purification of F(ab')2 fragments.

Animals↗
PubMed1992

Does an increase in prostaglandin E2 in the blood circulation contribute to a febrile response in rabbits?

We investigated the effect of intravenous injection of human recombinant interleukin-1 beta (IL-1) on rectal temperature and prostaglandin E2 concentration in venous and arterial blood and in the push-pull perfusate in the third ventricle of rabbits. Changes in plasma prostaglandin E2 concentration in blood obtained from the marginal ear vein paralleled changes in body temperature during both monophasic and biphasic fevers. The plasma concentration of prostaglandin E2 in blood obtained from the jugular vein increased during the first phase of the biphasic fever. However, no increase in the prostaglandin E2 level in the carotid arterial blood was observed during the biphasic fever. The levels of prostaglandin E2 in the push-pull perfusate in the third ventricle were markedly elevated during both monophasic and biphasic fevers. Intracarotid infusion of prostaglandin E2 did not produce a fever nor result in a change in the prostaglandin E2 concentration of the push-pull perfusate in the third ventricle. The present results suggest that prostaglandin E2 from the blood circulation does not contribute to fever production in rabbits.

Animals↗
PubMed1992

A pilot study to evaluate Japanese standard radiographs of pneumoconioses (1982) according to the ILO 1980 International Classification of Radiographs of Pneumoconioses.

The Japanese Classification of Radiographs of Pneumoconioses (JC) is characterized by its own standard films, including limit films which are defined to represent the upper limit of category 0 or the lower limit of category 1. This pilot study was aimed at evaluating the JC standard radiographs according to the ILO 1980 International Classification of Radiographs of Pneumoconioses (IC) in which some of the JC standards were read according to the IC by two groups of experienced British workers, four non-medically qualified (NM panel) and six medically qualified (MQ panel). The Japanese standard limit films, with rounded opacities of category 0/1 or 1/0, were classified by both groups as having lower categories in the IC than in the JC. With the standard mid-category films showing rounded or irregular opacities, the NM panel tended to produce higher categories than the MQ panel. From reading results by both panels, however, it may be said that the JC mid-category standards agree with the IC in terms of category.

Humans↗
PubMed1992

Dose-response study on covalent binding to forestomach protein from male F344 rats following oral administration of [14C]3-BHA.

A dose-response study on covalent binding to forestomach protein was performed using male F344 rats following oral administration of [14C]3-tert-butyl-4-hydroxyanisole (3-BHA). The order of tissue distribution of radioactivity 6 h after oral administration of 1% [14C]3-BHA was forestomach greater than glandular stomach greater than liver greater than kidney greater than plasma. The covalent binding levels to forestomach protein were very low until 0.1% 3-BHA, but rapidly increased at concentrations of 1% and 2% 3-BHA. The dose-response relations of 3-BHA levels to the covalent binding to protein coincided well with the incidence of forestomach papilloma reported previously. The binding levels of forestomach and glandular stomach were compared. In case of i.v. administration, both binding levels were almost the same, however, in case of 0.1% p.o. administration, the forestomach level was approximately 8-fold higher than the glandular stomach level. The binding level of forestomach protein by p.o. administration was approximately 54-fold higher than that by i.v. administration. Although the amount of tert-butylhydroquinone (BHQ) was very low compared with the amount of covalent binding, the BHQ levels in forestomach were dependent upon the dose levels of 3-BHA. Our study indicates that the dose-response study on covalent binding to target tissue protein is an efficient method for the quantitative estimation of the active metabolites coming from the chemicals which form the quinone metabolites.

Animals↗
PubMed1992

Calcium antagonistic and binding properties of semotiadil (SD-3211), a benzothiazine derivative assessed in cerebral and coronary arteries.

The present experiments were undertaken to elucidate Ca2+ antagonistic and binding properties of semotiadil and its (S)-(-)-enantiomer (SD-3212) in plausible clinical target tissues such as cerebral and coronary arteries. Semotiadil was about six times more potent than D-cis-diltiazem for Ca2+ antagonistic action, with a long-lasting and wide spectrum of inhibitory effects on contraction of dog cerebral arteries elicited by various spasmogens and mechanical stretch. Semotiadil exhibited a weak, negative, and heterotropic allosteric effect on (+)-[3H]PN 200-110 binding to pig coronary artery membranes: Scatchard analysis of saturation isotherms indicated that semotiadil increased the equilibrium dissociation constant (Kd) of (+)-[3H]PN-200-110 binding without causing a significant change in the maximum binding density (Bmax). Furthermore, semotiadil significantly increased the dissociation rate (k-1) of (+)-[3H]PN 200-110 from the specific binding site. The enhanced binding of (+)-[3H]PN 200-110 to the coronary artery caused by D-cis-diltiazem was attenuated when semotiadil was present, whereas binding inhibited by verapamil was not affected in the presence of semotiadil. The results suggest that semotiadil exerts a potent Ca2+ antagonistic action by binding to a site in the Ca2+ channel distinct from the 1,4-dihydropyridine recognition site and interacts with the 1,4-dihydropyridine binding site in a negative, heterotropic, allosteric manner.

Animals↗
PubMed1992

Comparison of rabies virus G proteins produced by cDNA-transfected animal cells that display either inducible or constitutive expression of the gene.

By using a retrovirus expression vector, pZIP-NeoSV(X)1, we introduced a cloned cDNA of the rabies virus G gene into BHK-21 cells and the NA cell clone originated from the murine neuroblastoma C1300 line. Using the neomycin resistance gene of the vector, we isolated several G418-resistant transformants of BHK-21 and NA cells (referred to as G-BHK and G-NA cells, respectively). G-BHK cells constitutively produced G proteins, whereas G-NA cells produced the proteins only when treated with sodium butyrate. G proteins synthesized in these transformants were transported normally to the surface of the cell, but they displayed different electrophoretic mobilities, which were shown to originate from differences in the number and structure of the carbohydrate moieties of the protein; G-BHK cells produced highly glycosylated and sialylated G proteins, whereas less glycosylated and much less sialylated G proteins were produced by G-NA cells as observed in virus-infected NA and BHK-21 cells, indicating that the glycosylation and sialylation of the G protein depend on the cellular conditions under which the protein was produced. In the absence of sodium butyrate the G protein was not detectable in G-NA cells either by immunoblot assay or fluorescent antibody staining, but the cells were fairly sensitive to syngeneic rabies virus-specific cytotoxic T lymphocytes, although the sensitivity was much increased by treatment with sodium butyrate.

Animals↗