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Biomedical subjects

H Kobayashi

Publications and source records attributed to H Kobayashi.

At least 397 records · Page 22Linked to original sources
PubMed2000

Potent preventive action of curcumin on radiation-induced initiation of mammary tumorigenesis in rats.

This investigation evaluated the preventive effect of curcumin on radiation-induced tumor initiation in rat mammary glands. Fifty-four female rats were mated and then divided into two groups at day 11 of pregnancy. As the control group, 27 rats were fed a basal diet during the experimental period. As the experimental group, 27 rats were fed a diet containing 1% curcumin between day 11 of pregnancy and parturition (day 23 of pregnancy). All rats of both groups received whole body irradiation with 1.5 Gy gamma-rays from a (60)Co source at day 20 of pregnancy and were then implanted with a diethylstilbestrol pellet 1 month after weaning. A high incidence (70.3%) of mammary tumorigenesis was observed in the control group. The tumor incidence (18.5%) was significantly reduced in the rats fed curcumin during the initiation stage. The appearance of the first palpable tumor was delayed by 6 months in the curcumin-fed group and the average latent period until the appearance of mammary tumors was 2.5 months longer in the curcumin-fed group than in the control group. By histological examination, the proportion of adenocarcinoma (16.7%) in total tumors in the curcumin-fed rats was found to be decreased to half that (32.1%) in the control group. Compared with the control rats, the body weight of rats in the experimental group was decreased slightly by administration of the curcumin diet from day 11 of pregnancy, in spite of a similar intake of diet, but had recovered to the level of the control by the end of the experiment. At the time of irradiation, curcumin did not have any effect on organ weight or on the development and differentiation of mammary glands of pregnant rats. In addition, the serum concentrations of fatty acids, thiobarbituric acid-reactive substances and ovarian and pituitary hormones, except LH, remained at the control level. Also, no change in litter size and body weight of pups born from curcumin-fed rats indicated no toxicity of curcumin. These results suggest that curcumin does not have any side-effects and is an effective agent for chemoprevention acting at the radiation-induced initiation stage of mammary tumorigenesis.

Animals↗
PubMed2000

Radiation-induced mammary tumors in virgin and parous rats administered contraceptive steroids, 17alpha-ethinylestradiol and norethisterone.

Oral contraceptives are used among women worldwide, and radiation is being used increasingly for diagnosis or therapy. We have investigated the effects of contraceptive steroids on the risk of mammary tumors initiated by radiation. Virgin rats received whole-body irradiation with 2.6 Gy gamma-rays 1 month after the administration of low- or high-dose pellets of contraceptive steroids, such as 17alpha-ethinylestradiol (EE(2)) combined with 19-norethisterone (NET). The high-dose pellet was removed 1 month after irradiation, but administration of the low-dose pellet was continued for up to 1 year. The incidence (33.3%) of mammary tumors initiated with radiation was not modified by the long-term administration of the low-dose pellets. However, the incidence (58. 3%) was increased significantly by the irradiation during administration of the high-dose pellets, but no significant difference in the proportion of adenocarcinoma and fibroadenoma was observed. Meanwhile, parous rats were irradiated with 2.6 Gy gamma-rays at weaning, a period of greater susceptibility to radiation, and then were implanted with the low-dose pellets 1 month later. The highest incidence (90%) of mammary tumors was detected in the parous rats. The proportion of adenocarcinomas in the parous irradiated rats increased significantly on treatment with the low-dose pellets. The results suggest that administration of the high-dose pellets of EE(2)-NET, but not of the low-dose pellets, enhances susceptibility to the initiation by gamma-rays of mammary tumors in virgin rats, and that the low-dose pellets act as a tumor promoter in the mammary glands of parous rats irradiated at weaning.

Animals↗
PubMed2000

Human myometrial cells in culture express specific binding sites for urinary trypsin inhibitor.

Urinary trypsin inhibitor (UTI), which is present in amniotic fluid, prevents uterine contractility during pregnancy possibly via specific binding protein mechanisms. To test for the presence of UTI binding sites on the cell surface, we prepared cultured myometrial cells obtained at biopsy from 12 pregnant women and performed binding, competition, and cross-linking experiments using a specific radiolabelled UTI as a ligand. We report for the first time two classes of binding sites of differing affinities. Scatchard analysis at 4 degrees C, using radioiodinated UTI, revealed that UTI binds to 35 000 high affinity binding sites/cell (K(d) = 9.1x10(-9) mol/l) and 450 000 lower affinity binding sites/cell (K(d) = 3.5x10(-7) mol/l) in cultured myometrial cells. It appears to be the low affinity site that is internalized, and this has been identified as a protein of approximately 45 kDa by cross-linking and immunoaffinity labelling studies. Monoclonal antibodies against the NH(2)-terminal fragment of UTI abrogated specific binding of this protein to the cells. Treatment of the cells with hyaluronidase resulted in >80% inhibition of the [(125)I]-labelled UTI binding to the cells. These data show that the UTI binding site, which is hyaluronidase sensitive, is expressed on the surface of human uterine myometrial cells to accumulate the UTI molecule during pregnancy.

Antibodies, Monoclonal↗
PubMed2000

The role of structural intersubunit microheterogeneity in the regulation of the activity in hysteresis of ribulose 1, 5-bisphosphate carboxylase/oxygenase.

Many enzymes are composed of subunits with the identical primary structure. It has been believed that the protein structure of these subunits is the same. Ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO) comprises eight large subunits with the identical amino acid sequence and eight small subunits. Rotation of the side chains of the lysine residues, Lys-21 and Lys-305, in each of the eight large subunits in spinach RuBisCO in two ways produces microheterogeneity among the subunits. These structures are stabilized through hydrogen bonds by water molecules incorporated into the large subunits. This may cause different effects upon catalysis and a hysteretic, time-dependent decrease in activity in spinach RuBisCO. Changing the amino acid residues corresponding to Lys-21 and Lys-305 in non-hysteretic Chromatium vinosum RuBisCO to lysine induces hysteresis and increases the catalytic activity from 8.8 to 15.8 per site per second. This rate is approximately five times higher than that of the higher-plant enzyme.

Catalysis↗
PubMed2000

Prognostic value of impaired myocardial fatty acid uptake in patients with acute myocardial infarction.

Impaired cardiac fatty acid uptake, assessed by the radiolabelled fatty acid analogue beta-methyl-p-iodophenyl pentadecanoic acid (I-123-BMIPP), is observed in the myocardium following acute ischaemic events, but the long-term prognostic implication has not been established. This study aimed to determine the prognostic value of cardiac BMIPP uptake in patients with acute myocardial infarction. Following the assessment of thallium-201 and I-123-BMIPP uptake, 101 post-infarct patients were prospectively followed up with primary end points of cardiac death, heart failure and non-fatal infarction. During a mean follow-up of 28 months, three cardiac deaths, three non-fatal infarctions, 23 revascularizations and four recurrences of angina pectoris were observed. Multivariate analysis identified reduced uptake of BMIPP and perfusion, no beta-blocking treatment and greater thallium-BMIPP mismatch (i.e. larger BMIPP defect than thallium defect) as significant predictors for overall cardiac events. Prior myocardial infarction, reduced left ventricular ejection fraction and greater thallium-BMIPP mismatch were selected as independent predictors of harder cardiac events. Female patients, those with greater BMIPP defect or greater thallium-BMIPP mismatch showed worse clinical outcomes. The inclusion of BMIPP data improved the prognostic values of conventional significant predictors. In conclusion, impaired myocardial I-123-BMIPP uptake and perfusion-BMIPP mismatch are related to a high probability of fatal and non-fatal cardiac events, suggesting the aetiological relevance and prognostic value of impaired cardiac fatty acid metabolism in viable, but jeopardized, myocardium following acute myocardial infarction.

Adult↗
PubMed2000

Expression of outer membrane proteins in Escherichia coli growing at acid pH.

It is generally accepted for Escherichia coli that (i) the level of OmpC increases with increased osmolarity when cells are growing in neutral and alkaline media, whereas the level of OmpF decreases at high osmolarity, and that (ii) the two-component system composed of OmpR (regulator) and EnvZ (sensor) regulates porin expression. In this study, we found that OmpC was expressed at low osmolarity in medium of pH below 6 and that the expression was repressed when medium osmolarity was increased. In contrast, the expression of ompF at acidic pH was essentially the same as that at alkaline pH. Neither OmpC nor OmpF was detectable in an ompR mutant at both acid and alkaline pH values. However, OmpC and OmpF were well expressed at acid pH in a mutant envZ strain, and their expression was regulated by medium osmolarity. Thus, it appears that E. coli has a different mechanism for porin expression at acid pH. A mutant deficient in ompR grew slower than its parent strain in low-osmolarity medium at acid pH (below 5.5). The same growth diminution was observed when ompC and ompF were deleted, suggesting that both OmpF and OmpC are required for optimal growth under hypoosmosis at acid pH.

Acids↗
PubMed2000

Novel toluene elimination system in a toluene-tolerant microorganism.

In studies of Pseudomonas putida IH-2000, a toluene-tolerant microorganism, membrane vesicles (MVs) were found to be released from the outer membrane when toluene was added to the culture. These MVs were found to be composed of phospholipids, lipopolysaccharides (LPS), and very low amounts of outer membrane proteins. The MVs also contained a higher concentration of toluene molecules (0.172 +/- 0. 012 mol/mol of lipid) than that found in the cell membrane. In contrast to the wild-type strain, the toluene-sensitive mutant strain 32, which differs from the parent strain in LPS and outer membrane proteins, did not release MVs from the outer membrane. The toluene molecules adhering to the outer membrane are eliminated by the shedding of MVs, and this system appears to serve as an important part of the toluene tolerance system of IH-2000.

Bacterial Outer Membrane Proteins↗
PubMed2000

A single amino acid substitution in a mannosyltransferase, WbdA, converts the Escherichia coli O9 polysaccharide into O9a: generation of a new O-serotype group.

wbdA is a mannosyltransferase gene that is involved in synthesis of the Escherichia coli O9a polysaccharide, a mannose homopolymer with a repeating unit of 2-alphaMan-1,2-alphaMan-1,3-alphaMan-1, 3-alphaMan-1. The equivalent structural O polysaccharide in the E. coli O9 and Klebsiella O3 strains is 2-alphaMan-1,2-alphaMan-1, 2-alphaMan-1,3-alphaMan-1,3-alphaMan-1, with an excess of one mannose in the 1,2 linkage. We have cloned wbdA genes from these O9 and O3 strains and shown by genetic and functional studies that wbdA is the only gene determining the O-polysaccharide structure of O9 or O9a. Based on functional analysis of chimeric genes and site-directed mutagenesis, we showed that a single amino acid substitution, C55R, in WbdA of E. coli O9 converts the O9 polysaccharide into O9a. DNA sequencing revealed the substitution to be conserved in other E. coli O9a strains. The reverse substitution, R55C, in WbdA of E. coli O9a resulted in lipopolysaccharide synthesis showing no ladder profile instead of the conversion of O9a to O9. This suggests that more than one amino acid substitution in WbdA is required for conversion from O9a to O9.

Amino Acid Sequence↗
PubMed2000

Ultrasound biomicroscopic analysis of pseudophakic pupillary block glaucoma induced by Soemmering's ring.

AIM: To perform ultrasound biomicroscopic analysis of pseudophakic pupillary block glaucoma induced by lens capsule and a Soemmering's ring and its resolution, and to elucidate the pathophysiology of this glaucoma. METHODS: A woman with pseudophakic pupillary block glaucoma underwent successful neodymium:YAG (Nd:YAG) laser photodisruption of the lens capsule through a laser iridotomised coloboma with resolution of the pupillary block. The Humphrey ultrasonic biomicroscope model 840 was employed to observe the anterior segment before and after laser photodisruption. RESULTS: Ultrasound biomicroscopic examination revealed the intraocular lens (IOL) was displaced forward, shallowing the central anterior chamber. The anterior hyaloid face was relatively posterior to the posterior capsule. The iris was in apposition to the anterior capsule, which was in touch with the IOL optics. A massive Soemmering's ring, which extended from the IOL optics to the ciliary processes, was displaced anteriorly. The Soemmering's ring consisted of several tightly packed layers. The ciliary processes rotated anteriorly. After Nd:YAG laser photodisruption of the capsule, ultrasound biomicroscopic images showed the resolution of the pupillary block and the anterior rotation of the ciliary process. The Soemmering's ring moved posteriorly, and the layers in the ring became loose. CONCLUSIONS: A massive Soemmering's ring may one of potential causes of pupillary block after cataract surgery. Ultrasound biomicroscopy is potentially useful as a non-invasive diagnostic technique for clinical diagnosis and differentiation between Soemmering's ring induced pupillary block glaucoma and other forms of pupillary block.

Aged↗
PubMed2000

Radiotherapy for subfoveal neovascularisation associated with pathological myopia: a pilot study.

BACKGROUND/AIM: Limited treatments are available for this disease process. A pilot study was performed to determine the toxicity and efficacy of external beam radiotherapy for subfoveal neovascular membranes and subretinal haemorrhage associated with pathological myopia. METHODS: A randomised, prospective study was carried out on 39 patients with subfoveal neovascularisation associated with high myopia. 20 patients underwent radiotherapy and the remaining 19 were observed as a randomised comparison group. All patients were followed up for at least 24 months. Subfoveal choroidal neovascular membranes (CNVMs) were treated with a single lateral 6 MV photon beam to a dose of 10 Gy in five fractions over 5-7 days. Post-treatment measurements included corrected visual acuity, area of CNVM, and occurrence of radiotherapy related complications, and adverse reactions. To assess changes of area of CNVM, the initial (pretreatment) size of the CNVM was set to 100%, and all post-treatment measurements were normalised relative to the initial size. RESULTS: No significant acute morbidity was noted. There was no significant difference in age, sex, refractive error, visual acuity, and area of CNVM at baseline between the treatment group and control group. The mean change of the size of the CNVM for 2 years was 155% (SD 156%) in the treatment group and 249% (124%) in the control group. The increase in the size of CNVM in the treatment group was significantly smaller than that in the control group (p = 0.0452). In the treated eyes, the visual acuity before and 1 and 2 years after radiotherapy were 0.111 (22.2/200), 0.091 (18.2/200), and 0.086 (19.2/200), respectively. In the control eyes, visual acuity before and 1 and 2 years after the start of the follow up were 0.141 (34.2/200), 0.089 (17.8/200), and 0.063 (12.6/200). The patients in the treatment group showed no significant change for 2 years, and those in the control group showed a significant decrease in the visual acuity (p = 0.0033). The changes of logMAR of visual acuity for 2 years after the start of the follow up were +0.019 (0. 443) in the treatment group and +0.347 (0.374) in the control group. There was a statistically significant difference between them (p = 0. 0173). Multiple regression analysis on the treatment group showed that the most significant predictive variable for the visual acuity 2 years after the treatment was the combination of pretreatment visual acuity and refractive error. CONCLUSIONS: Radiotherapy appeared to have a favourable treatment effect in eyes with subfoveal neovascular membranes and haemorrhage associated with pathological myopia. Further investigation is needed to evaluate the efficacy of radiotherapy for subfoveal neovascularisation associated with pathological myopia.

Aged↗
PubMed2000

Immunohistochemical study of annexin V expression in placentae of preeclampsia.

We investigated the clinical significance of annexin V in the placentae with preeclampsia and found: (1) annexin V was detected on trophoblasts in the placentae and the staining intensity of annexin V in the placentae from such patients was reduced when compared to normal placentae; (2) as expression of annexin V was reduced, the gestosis index from patients with preeclampsia was elevated and the standard deviation value in the infant's standard weight was decreased; plasma level of the fibrin degradation products and thrombin-antithrombin III complex from patients were elevated as the expression of anexin V was reduced. These results suggest that the reduced expression of annexin V in the placentae from patients with preeclampsia may lead to a hypercoagulable state in the intervillous space and may be associated with the development of intrauterine growth restriction.

Annexin A5↗
PubMed2000

Changes in plasma adenosine concentrations during normal pregnancy.

The aim of this study was to measure changes in plasma adenosine concentration [ADO] during a normal pregnancy and to evaluate the possible role of platelets and red blood cells (RBC) as causes of changes in plasma [ADO]. We measured the plasma [ADO] in normal pregnant women (n = 11) during the first, second and third trimesters. The mean plasma [ADO] in the third trimester was 0.41 +/- 0.08 microM (means +/- SEM), significantly higher than in the first and second trimesters (p < 0.05). In pregnant women, platelet and RBC counts, hematocrit and hemoglobin concentration decreased slightly throughout the pregnancy. The elevation in the plasma [ADO] correlated inversely with the platelet count (r = -0.43, p < 0.05). These results suggest that an increase in the plasma [ADO] in the third trimester may be attributed to the enhanced adenosine release from activated platelets.

Adenosine↗
PubMed2000

Invasive capacity of heterotopic endometrium.

Because endometriotic tissue is capable of implantation and invasion, it resembles neoplastic tissue. This biologic behavior is likely regulated by cell adhesion molecules and enzymes that degrade the extracellular matrix. A potential factor in the local regulation of tumor cell invasion is the urokinase-type plasminogen activator (uPA) system. This study was undertaken to characterize the expression of both uPA and its receptor (uPAR) in the eutopic and heterotopic endometrial cells from women with adenomyosis by testing both types of epithelial cells for invasive ability. By Western blot and zymographic analyses, stromal cells from heterotopic endometrium secreted 12 times more uPA antigen and uPA-dependent caseinolytic activity than did the eutopic stromal cells. The heterotopic epithelial cells overexpressed uPAR by a factor of four times the expression seen in the eutopic epithelial cells. When respective stromal cells were cocultured, the heterotopic epithelial cells exhibited significantly higher invasive ability through Matrigel than did the eutopic epithelial cells. uPAR overexpression in the epithelial cells and high secretion of uPA from the stromal cells may contribute to the invasive phenotype of heterotopic endometrium.

Biopsy, Needle↗
PubMed2000

Flow-mediated vasodilation and plasma fibronectin levels in preeclampsia.

To clarify the vascular endothelial function in pregnant women with hypertensive disorders, we assessed the flow-mediated vasodilation in the radial artery and compared it with plasma fibronectin levels. We determined flow-mediated vasodilation by measuring the change in radial artery diameter during hyperemia in 58 normal pregnant women, 22 preeclamptic pregnant women, and 15 pregnant women with chronic hypertension. In 41 of the 95 pregnant women, we measured the plasma fibronectin levels. Flow-mediated vasodilation in preeclamptic women was significantly less than that in normal pregnant women (P:<0.001). In chronic hypertensive women, flow-mediated vasodilation was significantly less than that in normal pregnant women (P:<0.001) but more than that in preeclamptic women (P:<0.001). Flow-mediated vasodilation showed significant negative correlation with plasma fibronectin levels (P:<0.001, r=0.73). Our results indicate that the endothelial function can be noninvasively assessed in pregnant women with hypertensive disorders by measuring the flow-mediated vasodilation of the radial artery with high-resolution ultrasound.

Adult↗
PubMed2000

Decreased protein C activation is associated with abnormal collagen turnover in the intraalveolar space of patients with interstitial lung disease.

Activation of the coagulation system in the alveolar space plays an important role in the pathogenesis of interstitial lung disease (ILD) and pulmonary fibrosis. The protein C (PC) pathway is the main modulator of coagulation activation. This study evaluated whether dysfunction of the PC pathway is associated with increased collagen synthesis in the intraalveolar space of patients with ILD. This study comprised 22 patients with ILD; of these, five had idiopathic pulmonary fibrosis (IPF), nine had sarcoidosis-associated ILD, and eight had collagen vascular disease-associated ILD (CVD-ILD). Thrombin-antithrombin complex (TAT) was measured as a marker of coagulation activation. As markers of the PC pathway activity, the concentration of activated PC-PC inhibitor (APC-PCI) complex and the APC-PCI/PC ratio were measured and, as a marker of collagen synthesis, the concentration of aminoterminal propeptide of type III procollagen (PIIINP) was measured in bronchoalveolar lavage fluid (BALF) of ILD patients. TAT was significantly increased in BALF from ILD patients as compared to control subjects. The concentrations of PIIINP were significantly elevated in patients with ILD as compared to healthy subjects. In contrast, the concentration of APC-PCI and the values of APC-PCI/PC ratio were significantly decreased in BALF from patients with ILD. BALF concentration of PIIINP was significantly and inversely correlated with the concentration of APC-PCI and with the APC-PCI/PC ratio. These findings suggest that dysfunction of the protein C pathway may have important physiopathologic implications in the development of pulmonary fibrosis in ILD.

Biomarkers↗
PubMed2000

The effect of different dosing schedules of UCN-01 on its pharmacokinetics and cardiohaemodynamics in dogs.

7-Hydroxy-staurosporine (UCN-01) is now under development as a novel anticancer drug. In clinical studies, different infusion schedules are being investigated in the USA and Japan. To examine the effect of different infusion schedules on the pharmacokinetics and cardiohaemodynamics of UCN-01, dogs were treated with UCN-01 as either a 3-h or a 24-h constant intravenous infusion. Blood pressure and heart rate, together with UCN-01 concentrations during and after infusion, were monitored. To analyse the relationship between the pharmacokinetics and cardiohaemodynamics of UCN-01, the plasma concentration of UCN-01 at the end of infusion (Cend), the area under the plasma concentration versus time curves (AUC0-infinity) and the mean residence time (MRT) were used. As indices of cardiohaemodynamic changes, the area under decreasing systolic blood pressure and increasing heart rate versus time curves (dAUCpressure and AUCheart rate) were calculated by the trapezoidal method. For the 3-h (0-22 and 0.65 mgkg(-1)) and 24-h infusion (0.81 to 6.48 mgkg(-1)), systolic and diastolic blood pressures fell after or during infusions, accompanied by a dose-dependent increase in heart rate for both infusions. During both infusion schedules, the plasma concentrations of UCN-01 gradually increased and Cend showed a dose-proportional increase. After that, UCN-01 was eliminated bi-exponentially with an elimination half-life of 5.14+/-1.12 to 8.32+/-1.80 h. The total clearance (CLtotal) ranged from 0.383 to 0.666+/-0.149 L h(-1) kg(-1). There was no significant difference in these parameters among the doses in each infusion schedule, indicating that UCN-01 has a linear pharmacokinetic profile over the dose range examined for each infusion, and there were also no significant differences between the 3-h and 24-h infusion except for MRT. The pharmacokinetic parameters of Cend, AUC0-infinity and slope0-3 h exhibited a degree of correlation with the AUCheart rate in the 3-h infusion and correlated significantly with the dAUCpressure in the 24-h infusion. The MRT did not correlate with cardiohaemodynamic changes during either infusion. In conclusion, the pharmacokinetic profile of UCN-01 after the shorter infusion is similar to that after the longer one. However, a longer dosing period of UCN-01 increased the residence time in comparison with the shorter infusion. This may be due to the effect on the circulatory function in dogs.

Alkaloids↗
PubMed2000

Identification of protein disulfide isomerase as a phorbol ester-binding protein.

A specific binding protein for 12-O-tetradecanoylphorbol 13-acetate (TPA), different from protein kinase C (PKC) and histone H1, was purified from HeLa cell extract by the use of affinity gel pendanted with phorbol ester (TPA-GEL). The purified binding protein was identified as protein disulfide isomerase (PDI, EC 5.4.3.1) by peptide sequence analysis. The dissociation constants (Kd's) of TPA to PDI, histone H1 and PKCalpha were determined to be 1.03 x 10(-6) M, 5.70 x 10(-7) M, and 4.00 x 10(-7) m, respectively, by the surface plasmon resonance (SPR) method. TPA moderately inhibited PDI activity assessed in terms of reactivation of denatured RNase A.

Amino Acid Sequence↗