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Biomedical subjects

M Takada

Publications and source records attributed to M Takada.

At least 145 records · Page 8Linked to original sources
PubMed1998

Inhibition of cyclin D1 expression and induction of apoptosis by inostamycin in small cell lung carcinoma cells.

Previously, we demonstrated that inostamycin, an inhibitor of phosphatidylinositol turnover, caused cell cycle arrest at the G1 phase, inhibiting the expression of cyclins D1 and E in normal cells. In the present study, we examined the effects of inostamycin on cell cycle progression and apoptosis in human small cell lung carcinoma Ms-1 cells. Treatment of exponentially proliferating Ms-1 cells with low concentrations of inostamycin caused cells to accumulate in the G1 phase. We found that inostamycin decreased cyclin D1, and increased cyclin-dependent kinase inhibitors such as p21WAF1 and p27KIP1 in Ms-1 cells. On the other hand, higher concentrations of inostamycin induced morphological apoptosis and DNA fragmentation in Ms-1 cells without affecting the expression of p53, Bcl-2 and Bax. Inostamycin-induced apoptosis was suppressed by an inhibitor of caspase-3, and a 17 kDa fragment of activated caspase-3 was detected following inostamycin treatment. Therefore, caspase-3(-like) would appear to be involved in inostamycin-induced apoptosis. On the other hand, an inhibitor of caspase-3(-like) proteases did not affect the inhibitory effect of inostamycin on cyclin D1 expression, suggesting that caspase-3(-like) proteases were not responsible for inostamycin-induced G1 arrest.

Anti-Bacterial Agents↗
PubMed1998

Caspase-3 activation is not responsible for vinblastine-induced Bcl-2 phosphorylation and G2/M arrest in human small cell lung carcinoma Ms-1 cells.

Vinblastine arrests cells in the G2/M phase of the cell cycle and subsequently induces cell death by apoptosis. We found that treatment of cells with vinblastine induced phosphorylation of Bcl-2, resulting in the dissociation of Bcl-2 and Bax. Moreover, vinblastine-induced apoptosis was suppressed by an inhibitor of caspase-3, Ac-DEVD-CHO; and a 17-kDa active fragment of caspase-3 was detected following vinblastine treatment, suggesting that caspase-3 is involved in vinblastine-induced apoptosis. However, Ac-DEVD-CHO affected neither vinblastine-induced Bcl-2 phosphorylation nor vinblastine-induced G2/M arrest. Vinblastine caused G2/M arrest prior to apoptosis, whereas vinblastine-induced apoptosis was not dependent on the duration of the G2/M phase. Thus, vinblastine-induced apoptosis might be mediated by the phosphorylation of Bcl-2, resulting in Bcl-2 inactivation, and by subsequent activation of caspase-3.

Apoptosis↗
PubMed1998

Potentiation of paclitaxel cytotoxicity by inostamycin in human small cell lung carcinoma, Ms-1 cells.

In the present study, we found that inostamycin increased the ability of paclitaxel to induce apoptosis in Ms-1 cells. A considerably higher concentration of paclitaxel was required for the induction of apoptosis in Ms-1 cells than in other cell lines tested. Treatment of Ms-1 cells with inostamycin, an inhibitor of phoshatidylinositol (PI) synthesis, reduced the dosage of paclitaxel required to induce cell death by apoptosis. This effect of inostamycin is specific to Ms-1 cells, and inostamycin did not increase the cytotoxicity of other antitumor drugs such as adriamycin, vinblastine, methotrexate, cisplatin, etoposide, or camptothecin in Ms-1 cells. Addition of inostamycin to paclitaxel-treated cells caused a significant increase in the sub G1 peak, representing apoptosis, which was accompanied by a decrease in the G2/M peak seen in paclitaxel-treated Ms-1 cells, without affecting paclitaxel-inhibited tubulin depolymerization. Moreover, paclitaxel did not enhance inostamycin-inhibited PI synthesis. The expression levels of Bcl-2, Bax, and Bcl-XL were not changed following the co-treatment with inostamycin plus paclitaxel, whereas the activated form of caspase-3 was markedly increased. Thus, inostamycin is a chemosensitizer of paclitaxel in small cell lung carcinoma Ms-1 cells.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

Using polymerase chain reaction for rapid sex-determination of a case of sirenomelia.

A rare case of sirenomelia with its autopsy findings is reported. The 1188 g infant was delivered by cesarean section at the 36th week of gestation, and died at 4 h of life. Physical and pathologic findings included sirenomelia (a single lower extremity mass), lung hypoplasia, bilateral renal agenesis, blind-ending colon, severe deformity of the bony pelvis, an imperforate anus, absence of the bladder, and a single umbilical artery. Because of the difficulty in determining the sex of the infant, PCR directed against the SRY gene was performed. The PCR-based sex determination is a rapid technique in patients with ambiguous genitalia.

Autopsy↗
PubMed1998

Ionic-diffusion potential-dependent transport of a new quinolone, sparfloxacin, across rat intestinal brush-border membrane.

The mechanism of uptake of sparfloxacin, a new quinolone, by intestinal brush-border membrane vesicles was investigated to clarify whether there is a common transport process for new quinolones mediated by the diffusion potential across the intestinal membrane bilayer. Sparfloxacin was taken up pH-dependently by rat intestinal brush-border membrane vesicles, behaviour analogous to that of organic cations including enoxacin and ciprofloxacin. Transient overshooting uptake of this quinolone was observed in the presence of an outward H+ gradient. Momentary dissipation of the H+ gradient by addition of carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone did not affect the uptake of sparfloxacin, and a marked but incomplete reduction in the H+-sensitive overshooting uptake of sparfloxacin was apparent in the voltage-clamped brush-border membrane vesicles. Furthermore, a valinomycin-induced K+-diffusion potential (interior negative) and an inward C1--diffusion potential stimulated the initial uptake of sparfloxacin at pH 5.5. Sparfloxacin uptake was inhibited by tetracaine and imipramine. The inhibitory effect of these cations correlated well with changes in membrane surface charges induced by the presence of tetracaine or imipramine. These results indicate that sparfloxacin transport across the brush-border membrane depends upon the inside-negative ionic diffusion potential, that the H+- or K+-diffusion-potential-dependent uptake of sparfloxacin by intestinal brush-border membrane vesicles is affected by the membrane surface potential and that inhibition of sparfloxacin uptake originates from changes in the membrane surface potential caused by the organic cations.

Animals↗
PubMed1998

Effect of calcium on development of amiloride-blockable Na+ transport in axolotl in vitro.

The axolotl, Ambystoma mexicanum, which has no specific calcium-containing sieve layer in the dermis, provides useful material for the study of the effect of Ca2+ on the development of amiloride-blockable active Na+ transport across the skin of amphibians. We raised axolotls in thyroid hormone or aldosterone or cultured the skin with corticoid plus one of several Ca2+ concentrations and found that 1) although the short-circuit current (SCC) was increased by both aldosterone and 3,3',5-triiodo-L-thyronine in vivo, only corticoid was necessary for such an increase in vitro; 2) the development of the SCC in vitro was both corticoid and Ca2+ dependent, because the SCC was well developed with over 100 microM Ca2+ but not with under 10 microM Ca2+ in the presence of corticoid, nor even with 300 microM Ca2+ without corticoid; and 3) Ca2+, but not corticoid, was necessary for the formation of cell-to-cell junctions, because the resistance of the skin was well developed with 300 microM Ca2+ without corticoid.

Aldosterone↗
PubMed1998

Effect of side chains including the N-methyl-tetrazole-thiol group of beta-lactam antibiotics on transport in cultured kidney epithelial cells LLC-PK1.

In this study, the transcellular transport characteristics of four beta-lactam antibiotics (cefotaxime, cefmenoxime, cefmetazole, and cefotiam) were investigated in a kidney epithelial cell line LLC-PK1, especially focusing on the effect of the N-methyl-tetrazole-thiol (NMTT) group attached to 7-amino-cephalosporanic acid. There were no directional differences between the apical-to-basolateral and basolateral-to-apical transport of cefotaxime, cefmenoxime, and cefmetazole, suggesting that the NMTT group does not influence the transcellular transport behaviors of beta-lactam antibiotics. In contrast, cefotiam transport across LLC-PK1 cell monolayers was 1.3-fold greater in the basolateral-to-apical direction than in the apical-to-basolateral direction. It is considered that the ionization of nitrogen in the N-dimethylaminoethyl group attached to NMTT is a factor in the secretory-oriented movement of cefotiam. The transcellular transport of cefotiam in both directions was significantly depressed at a low temperature (4 degrees C) and by 2,4-dinitrophenol. The basolateral-to-apical transport of cefotiam was also shown to be concentration-dependent. These results suggest that a specialized transport process might participate in the transcellular transport of cefotiam. The lipophilicities of these beta-lactam antibiotics were not correlated to the degree of transcellular transport, directly.

Animals↗
PubMed1998

Uptake of doxorubicin by cultured kidney epithelial cells LLC-PK1.

The renal handling of doxorubicin (DXR) was investigated using a kidney epithelial cell line, LLC-PK1. The uptake of DXR by LLC-PK1 cells cultured on plastic dishes was shown to be temperature and concentration dependent. The initial uptake of DXR was slightly saturable. The Km and Vmax of the saturable component were calculated to be 20.2 microM, and 0.355 nmol/mg protein/10 min, respectively. The release of DXR from LLC-PK1 cells was very slow at 37 degrees C and almost negligible at 4 degrees C, indicating that most of the DXR in the cells irreversibly binds to cellular constituents and that only a slight amount of unbound DXR participates in the efflux out of the cells. DXR uptake at 37 degrees C was significantly decreased in the presence of 2,4-dinitrophenol. However, organic cations and aminoglycoside antibiotics, such as tetraethylammonium, N1-methylnicotinamide, guanidine, gentamicin and neomycin, did not inhibit DXR uptake, suggesting that a process distinct from the organic cation transport system and absorptive endocytosis might be involved in the uptake of DXR by LLC-PK1 cells.

Alkaline Phosphatase↗
PubMed1998

A rapid assay of granisetron in biological fluids from cancer patients.

A convenient high-performance liquid chromatography (HPLC) was developed for the rapid assay of granisetron (GRN) in biological fluids, such as serum, urine, and pleural effusion, from cancer patients. Extrelut-1 was used for the solid-phase extraction. HPLC was carried out using a LiChroCART cartridge column packed with Lichrospher 100 CN and a mobile phase consisting of 0.1 M acetate buffer (pH 3.5) and acetonitrile (7:3). A fluorescence detector of 290 nm for excitation and 365 nm for emission was used. The standard curve was linear over the range of 2 to 100 ng/ml of GRN. Assay precision, expressed as a coefficient of variation (C.V.), was in the range of 0.9-5.4% in the within-day assay and 2.5-6.9% in the between-day assay, respectively. GRN was well separated on the HPLC chromatogram from drugs such as etoposide, metclopramide, ondansetron, and domperidone which are often used together with GRN. It was suggested that the present method is useful for the rapid monitoring of GRN in the serum, urine, and pleural effusion of patients undergoing cancer chemotherapy.

Antiemetics↗
PubMed1998

The characteristics of endothelin receptor subtypes on muscle contraction and neuro-transmission in rat vas deferens.

We observed endothelin (ET)-induced contractile responses on prostatic and epididymal segments, as well as the facilitation of an electrically stimulated tone on prostatic segments of isolated rat vas deferens. In both segments, the selective ET(B)-receptor agonists, IRL 1620 and sarafotoxin S6c, produced only a small contraction or no contraction at a concentration of 1 microM. The rank order of contraction potencies (pD2 value) was ET-1 = ET-2 > ET-3 >> sarafotoxin S6c = IRL 1620. The maximum responses of ET-induced contractions in the prostatic segments were larger than those in the epididymal segments. The contractile response to ET-3 was antagonized by pretreatment for 30 min with BQ-123 (10 nM), a selective ET(A) receptor antagonist, and BQ-788 (1 microM), a selective ET(B) receptor antagonist. The contractile responses to ET-1 were antagonized by pretreatment with BQ-123 (10 microM), but not with BQ-788 (1 microM). The ET-3-induced facilitation on the twitch response to electrical stimulation in the prostatic segment of the vas deferens was antagonized by BQ-123 (0.1 microM) and BQ-788 (1 microM). The ET-1-induced facilitation was antagonized by pretreatment with BQ-123 (3 microM), but not with BQ-788 (10 microM). These results suggest that in rat vas deferens the ET(A) receptors are divided into BQ-123-sensitive ET(A1) and BQ-123-insensitive ET(A2) subtypes, and the production of a contractile response of smooth muscle as well as the facilitation of neurotransmission are accomplished through mediation by ET(A1)- and ET(A2)-subtypes.

Animals↗
PubMed1998

Association of insulin resistance and hyperinsulinemia with disturbed lipid metabolism in patients with essential hypertension.

To clarify the association of insulin resistance and hyperinsulinemia with lipid metabolism in patients with essential hypertension (EHT), we used the euglycemic hyperinsulinemic glucose clamp technique (GC) and the 75-g oral glucose tolerance test (OGTT) to compare the characteristics of glucose and lipid metabolism in insulin-resistant patients with essential hypertension (EHT-R) with those in insulin-non-resistant patients with essential hypertension (EHT-N) and normotensive subjects (NT). Twenty-eight NT and 42 EHT whose body mass index (BMI) was less than 28 kg/m2 were studied to eliminate the effects of obesity on insulin sensitivity and lipid metabolism. Insulin sensitivity was evaluated by GC and expressed as metabolic clearance rate of glucose (M value, mg/m2/min). Mean -ISD of the M value in NT (145.0 mg/m2/min) was chosen as the cutoff point for insulin resistance. On the basis of this value, 33.3% of the EHT were EHT-R. There was no significant difference in age or BMI among the three groups. Blood samples were collected before GC to measure levels of total cholesterol (TC), triglyceride (TG), free fatty acid (FFA), and HDL cholesterol (HDL-C). EHT-R had significantly higher levels of fasting blood sugar, fasting immunoreactive insulin, insulin at 120 min (IRI-120), and summation of insulin or blood sugar (BS) during the OGTT, as compared with NT and EHT-N. EHT-R also had significantly higher FFA and TG than the other two groups, while there was no difference in FFA or TG between EHT-N and NT. TC and HDL-C were similar in the three groups. There was either a significant negative correlation, or a trend toward negative correlation, between M value and FFA (r= -0.50, p < 0.05) or TG (r= -0.24, p < 0.1). There were significant positive correlations between IRI-120 and FFA (r=0.35, p< 0.05) or TG (r=0.29, p< 0.05). There was a positive correlation (r= -0.36, p< 0.01) between sigma BS and FFA, while no other significant relation was found between sigma BS and serum lipids. In summary, (i) 33.3% of EHT were found to be insulin resistant, when insulin resistance was defined as M value < 145.0 mg/m2/min, i.e., mean -ISD of the M value of NT; (ii) these EHT-R had higher levels of BS, insulin, FFA, and TG than did NT and EHT-N; (iii) EHT-N showed no difference in the levels of BS, insulin, or lipid, as compared with NT; and (iv) the levels of FFA and of TG correlated negatively with insulin sensitivity and positively with the insulin level during the OGTT. These results suggest that disturbances of glucose and lipid metabolism in EHT may be related to both insulin resistance and compensatory hyperinsulinemia, and that EHT-R may have more risk factors for arteriosclerotic complications than EHT-N.

Blood Glucose↗
PubMed1998

Insulin-like growth factors - insulin-like growth factor binding protein axis and diabetic control in insulin-dependent diabetes mellitus.

There is some evidence that insulin-like growth factors (IGFs) and/or IGF binding proteins (IGFBPs) (IGF-IGFBP axis) may be involved in glucose metabolism. The purpose of this study was to investigate the relationship between the IGF-IGFBP axis and diabetic control in subjects with insulin-dependent diabetes mellitus (IDDM). Thirty-nine subjects with IDDM without major complications (age: 5.8-30.3 years, 13 males and 26 females) participated in this study. In all subjects, the free form of IGF-I (free IGF-I), the total IGF-I (total IGF-I: free plus complexed form of IGF-I) and IGFBP-3 in serum or plasma were measured. The Z-scores of free IGF-I, total IGF-I, and IGFBP-3 were calculated. In 18 young adults with IDDM (age 18.0-30.3 years, 5 males and 13 females), IGFBP-1 in serum was also measured. In all subjects, the diabetic control parameters such as blood glucose (BS) (momentary control), 1,5-anhydro-D-glucitol (1,5 AG) (Ultrashort-term), fructosamine (short term), and glycosylated hemoglobin (HbA1) (long-term) were measured. None of the Z scores for free IGF-I, total IGF-I or IGFBP-3 had a significant correlation with BS. In young adults, IGFBP-I was correlated with BS (r=0.57, P<0.005). None of the Z scores for free IGF-I, total IGF-I or IGFBP-3 had a significant correlation with 1,5 AG, fructosamine or HbA1. In young adults, IGFBP-1 did not correlate with 1,5 AG, fructosamine or HbA1. These data suggested that the IGF-IGFBP axis did not reflect diabetic control in subjects with IDDM under treatment.

Adolescent↗
PubMed1998

[In vitro study of ultrasonic bone densitometry using dissected calcaneus].

Quantitative ultrasound (QUS) of the calcaneus is a widely utilized method for bone densitometry. However, the meaning of measured parameters, such as speed of sound (SOS) and broadband attenuation (BUA), is not well established. We performed in vitro measurement of dissected human calcaneus (n = 60; male 29, female 31; mean age 81 years) using two QUS machines and also measured bone densities using SXA, DXA and pQCT. Finally, we investigated breaking strength of the calcaneus and studied the correlation with QUS parameters and other assessed parameters. The two QUS measurements were in good agreement in most experiments. SOS correlated most closely with bone mineral densities assessed by pQCT and did not correlate with factors related to bone size, while BUA showed the highest correlation with BMC and association with parameters related with bone size such as bone area and bone width. With maximal breaking stress of the calcaneus, correlations were almost equal among QUS parameters and bone mineral density. We conclude that SOS is the parameter most closely associated with true bone mineral density (g/cm3), whereas BUA represents both bone mineral density and bone size, mimicing BMD assessed by DXA or SXA.

Aged↗
PubMed1998

[Recent development and clinical application of bone mineral measurements].

Over the past decade, methodologies for the assessment of bone mineral density have markedly progressed, so that any sites of the skeleton now can be measured with high degree of accuracy and precision with safety. The number of devices distributed in Japan rapidly increased for the last 5 years and the total number installed nationwide reached over 7000 as with 1998. There are variety of techniques: microdensitometry (MD) or radiographic absorptiometry (RA), single X-ray absorptiometry (SXA), dual X-ray absorptiometry (DXA), quantitative CT (QCT), peripheral QCT, and quantitative ultrasonometry (QUS). There are, however, no such single technique as to fulfill the entire clinical requirements, since the time of initiation of bone loss, and the speed of bone loss are quite different from site to site of the skeleton, so that the correlations of bone density measured by each technique are not sufficiently high (gamma = 0.5-0.8) to predict BMD of other bones by measuring one bone. Since the relatively large amounts of data on the prediction of fracture (hip, spine and others) by these techniques have been accumulated, a specific guideline regarding the appropriate application of these techniques, including multiple combination measurements, should be established based on the worldwide consensus.

Bone Density↗
PubMed1998

[A phantom study for the evaluation of the effect of the high uptake in the liver on technetium-99m myocardial perfusion SPECT images].

The purpose of this study was to evaluate influences of the high hepatic uptake on parameters such as filtering, attenuation coefficient, and scatter correction at reconstructing of the myocardial SPECT images. Hepatic and cardiac spaces of a myocardial phantom (RH-2, Kyoto Kagaku), were filled with technetium-99m and a three-detector SPECT system (GCA 9300-DI, TOSHIBA) was used. The hepatic activity's influence was estimated from a qualitative percent regional scattering and the effects of attenuation and scatter correction were evaluated by a circumferential profile curve. Percent regional scattering increased in reverse to hepato-cardiac distance (HCD) and in proportion to hepatic to cardiac activity ratio (HCR). This tendency was observed the most significantly in the inferior region, followed by in the lateral, anterior and septal regions, declining in this order. An artifactual defect adjacent to the liver was observed when HCR is three and HCD is zero. However, when the Butterworth filter was used with small filtering-sizes and lower orders in combination with attenuation and scatter correction, the defects were decreased up to 15% at counts in the inferior region. This study showed that the hepatic to cardiac activity ratio, and the hepatocardiac distance should be considered for reconstruction of the SPECT images.

Artifacts↗
PubMed1997

Prevention of late renal changes after initial ischemia/reperfusion injury by blocking early selectin binding.

BACKGROUND: Increasing clinical evidence suggests that delayed initial function secondary to ischemia/reperfusion injury alone, and particularly in combination with early episodes of acute rejection, reduces kidney allograft survival over time. METHODS: We investigated changes developing over the long term following a standardized ischemia/reperfusion insult in a Lewis rat model. The left kidney was isolated in a uninephrectomized host and cooled, and the pedicle was clamped for 45 min. Animals were followed for 48 weeks after initial renal injury. Organs were removed serially (4, 8, 16, 24, 32, 40, and 48 weeks) for immunohistology and reverse transcriptase polymerase chain reaction. RESULTS: Progressive proteinuria developed after 8 weeks. By immunohistology, CD4+ leukocytes and ED-1+ macrophages infiltrated the ischemic organs in parallel with up-regulation of major histocompatibility complex class II antigen expression. Because macrophages have been shown to be critical in chronic changes in other models, they were examined primarily in these studies. By reverse transcriptase polymerase chain reaction, macrophage-derived, fibrosis-inducing factors (transforming growth factor-beta, interleukin 6, and tumor necrosis factor-alpha) remained highly and constantly expressed throughout the follow-up period. The long-term influence of initial treatment with the soluble form of P-selectin glycoprotein ligand-1, a soluble ligand for P- and E-selectin, was then examined. All functional and structural changes remained at relative baseline, similar to uninephrectomized controls. CONCLUSIONS: These data suggest that blocking the initial selectin-mediated step after ischemia/reperfusion injury, which triggers significant early cellular and molecular events, also reduces later renal dysfunction and tissue damage over time. In part, the findings may be explained by the sparing of functioning nephron units, which if destroyed or compromised by the original insult, may contribute to long-term graft failure. This approach may be important clinically in the transplantation of kidneys from non-heart-beating or marginal donors or organs experiencing prolonged ischemic times.

Animals↗
PubMed1997

Corticosubthalamic input zones from forelimb representations of the dorsal and ventral divisions of the premotor cortex in the macaque monkey: comparison with the input zones from the primary motor cortex and the supplementary motor area.

Employing double anterograde axonal tracing in combination with intracortical microstimulation, we examined the distribution patterns of corticosubthalamic inputs from forelimb representations of the dorsal (PMd) and ventral (PMv) divisions of the premotor cortex in the macaque monkey. The inputs from the PMd and PMv were distributed mainly in the medial aspect of the subthalamic nucleus (STN), in which their distribution areas overlapped each other. By the same experimental approach, we further compared corticosubthalamic input zones from the PMd/PMv with those from the primary motor cortex (MI) and the supplementary motor area (SMA). The input zones from the PMd/PMv and SMA largely overlapped in the medial aspect of the STN, whereas the input zones from the PMd/PMv and MI were virtually segregated mediolaterally in the STN.

Animals↗