Search PubMed⌕ Search

Biomedical subjects

H Ito

Publications and source records attributed to H Ito.

At least 505 records · Page 28Linked to original sources

Quantitative determination of E5880 in rat plasma by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry.

A simple and sensitive method is described for the determination of E5880 in rat plasma. The method is based on high-performance liquid chromatography/electrospray ionization mass spectrometry, using deuterated E5880 as an internal standard. Selected reaction monitoring is employed for selectivity and sensitivity, this in turn enables quantification in a short period of time (within 7 minutes) over the extended range of 0.1-1000 ng/ml with acceptable precision and accuracy. The method demonstrated to be suitable for the quantitative analysis of E5880 in rat plasma. The pharmacokinetic profile of E5880 after a single intravenous administration of E5880 was elucidated.

Animals↗

In vitro analysis of the stimulation of bone formation by highly bioactive apatite- and wollastonite-containing glass-ceramic: released calcium ions promote osteogenic differentiation in osteoblastic ROS17/2.8 cells.

We analyzed the mechanisms of the efficient bone formation on the osteoconductive surface of apatite- and wollastonite-containing glass-ceramic (AW) by using an in vitro system. AW releases Ca ions and bonds to bone via a submicron-thick hydroxycarbonate apatite (HCA) layer. AW disks were conditioned with simulated body fluid (SBF) to grow HCA layers, and the amount of released Ca ion was regulated by modulating the conditioning time from 24 to 240 h. Surface-transformed AW disks increased alkaline phosphatase (AP) activity in osteoblastic ROS17/2.8 cells by 1.5- to threefold over unconditioned disks. AW disks conditioned for 24 h [AW(24)], which had a homogeneous, submicron-thick apatite layer and increased extracellular ionized Ca concentration ([Ca(2+)](e)) in the culture medium to the greatest extent, enhanced the AP activity the most. High [Ca(2+)](e) promoted osteogenic differentiation in ROS17/2.8 cells: It increased AP activity in a dose-dependent manner by up to 1.6-fold, and up-regulated the expression of AP, osteocalcin (OC), and transforming growth factor-beta1 mRNAs in dose- and time-dependent manners. AW(24) enhanced AP activity in ROS17/2.8 cells as much as AW disks conditioned with SBF containing serum to exhibit in vivo surface-structure changes. AW(24) increased AP activity in ROS17/2.8 cells by 1.6-fold and enhanced the expression of AP and OC mRNAs significantly, compared with sintered hydroxyapatite (HA). After implantation of AW and HA in the distal metaphyses of rabbit femurs, thin, newly formed bone lined with cuboidal, osteoblast-like cells was characteristically observed adjacent to the AW surface within 8 days. These results provide evidence for the hypothesis that AW stimulates bone formation on its surface by increasing [Ca(2+)](e) to promote the HCA layer formation and the differentiation of osteogenic cells.

Animals↗

Positive and negative regulation of chondrogenesis by splice variants of PEBP2alphaA/CBFalpha1 in clonal mouse EC cells, ATDC5.

The alphaA type of the alpha subunit of the polyomavirus enhancer binding protein 2 (PEBP2alphaA), also called the core binding factor alpha1 (CBFalpha1) or til-1, plays crucial roles in osteogenesis. Little is known, however, about the function of PEBP2alphaA in chondrogenesis. Here, we examined the role of PEBP2alphaA in chondrogenesis of clonal mouse embryonal carcinoma cells, ATDC5, which are committed as chondroprogenitors. We found that as ATDC5 cells condensed and formed cartilaginous nodules, PEBP2alphaA increased, and the level was maintained throughout the process of chondrocytic maturation. When an established dominant negative form of PEBP2alphaA was introduced in undifferentiated ATDC5 cells, the cellular condensation and the subsequent processes were inhibited. This inhibition was overcome with BMP-4 treatment, which increased the endogenous expression of PEBP2alphaA. Thus, the process of chondrogenesis is regulated by the level of PEBP2alphaA activity. Along with the wild-type PEBP2alphaA, a splice variant form, til-1 G2, is naturally expressed in ATDC5 cells. In luciferase reporter assays, til-1 G2 not only exhibited a limited ability to transactivate the osteocalcin promoter but also inhibited the activity achieved by the wild-type PEBP2alphaA. When til-1 G2 was overexpressed by stable transfection in undifferentiated ATDC5 cells, it inhibited the progression of chondrogenesis. Therefore, we conclude that PEBP2alphaA acts as a positive regulator of chondrogenesis, and that this positive effect may be finely tuned by the opposing effect of the til-1 G2 isoform.

Alternative Splicing↗

Metastasis suppressor gene(s) for rat prostate cancer on the long arm of human chromosome 7.

Allelotype analyses of human prostate cancer indicate that allelic losses on human chromosome arms 7q, 8p, 10q, 13q, 16q, 17q, and 18q are observed frequently. For the study of the possible biological significance of the frequently observed deletions on chromosome arm 7q in human prostate cancer, human chromosome 7 was introduced into highly metastatic rat prostate cancer cells by use of a microcell-mediated chromosome transfer technique. The introduction of human chromosome 7 resulted in the suppression of metastatic ability of the microcell hybrids, whereas no suppression of tumorigenicity was observed. To identify the portion of chromosome 7 containing the metastasis-suppressive function gene, the derivative chromosome 7 that was generated with the initial transfer was retransferred into rat prostate cancer cells. Human chromosome 7-containing rat prostate cancer cells could be used as the donor cells, because rodent cells produced a sufficient number of microcells with colchicine treatment. Cytogenetic and molecular analyses of these clones demonstrated that loss of segments on 7q was related to the reexpression of the metastatic phenotype. These results show that human 7q contains a metastasis suppressor gene or genes for rat prostate cancer. The findings also suggest that this gene may play an important role in the progression of human prostate cancer.

Animals↗

Variation in urinary flow according to voiding position in normal males.

Our objective was to study whether the urinary flow rate would vary according to voiding position. Twenty-one normal healthy male volunteers aged 24 to 40 years (mean, 29 years) were studied. The bed used was designed so that a hole could be opened at its center for voiding, and the bed could be bent at two points so that the subject could void in various positions. Urinary flow was measured with a portable uroflowmeter (P-Flow), which permits measuring urinary flow rate. Each subject assumed five voiding positions (standing, sitting, lateral, supine, and prone) in random order. Urinary flow was measured at least twice in each position to record a stable voiding. For voiding in the lateral position, subjects were instructed to void while bending the upper leg to keep an open angle between the legs. All subjects were also instructed to void without increasing abdominal pressure. Maximum flow rate was 20.7 +/- 6.59 mL/sec with voided volume of 262 +/- 77.8 mL in the lateral, 22.1 +/- 7.05 mLl/sec with voided volume of 309 +/- 130 mL in the supine, 25.0 +/- 8.25 mL/sec with voided volume of 287 +/- 122 mL in sitting, 27.1 +/- 8.89 mL/sec with voided volume of 263 +/- 102 mL in the standing, and 28.7 +/- 10.6 mL/sec with voided volume of 303 +/- 98 mL (mean +/- SD) in the prone positions. The maximum and mean urinary flow rates were greatest in the prone position. With regard to these parameters, significant differences were noted between the prone and lateral positions and between the prone and supine positions. In conclusions, the maximum urinary flow rate was highest in the prone position, followed by the standing, sitting, supine, and finally the lateral positions in normal males. Neurourol. Urodynam. 18:553-557, 1999.

Adult↗

Electrophoretic analysis of oxidative modification of apolipoprotein E in very low density lipoprotein from fresh human plasma.

Ferrous ion-induced oxidative modification of apoE in lipid peroxidation of human very low density lipoprotein (VLDL) and the role of the cysteinyl group, present in apoE3 but absent in apoE4, were examined. Fresh human VLDL was obtained from healthy volunteers with different apoE phenotypes as determined by isoelectric focusing (IEF). The VLDL was oxidized by incubating with FeSO4. The time course of the lipid peroxidation was determined by thiobarbituric acid (TBA) assay. The sequential oxidative modification of the apoE was demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting with an anti-apoE antibody. To modify the cysteinyl group of apoE3, the VLDL from the apoE3/3 subject was pretreated with cysteamine before the TBA assay and electrophoresis. The ferrous ion-induced peroxidation of the VLDL was pH-dependent, with increased reactivity at acidic pH ranges. In the initial stage of the lipid peroxidation of the VLDL, aggregates were formed involving apoE dimers and apoB via disulfide bonds, followed by the intra- and intermolecular cross-linkings of apoE monomers. The VLDL with apoE3/4 showed a shorter lag time than the VLDL with apoE3/3 in the TBA assay, suggesting a lower antioxidative effect with apoE3/4. The apoE3/3 pretreated with cysteamine showed the patterns of apoE3/4 in IEF and SDS-PAGE with immunoblotting, but it did not show the shortened lag time in the TBA assay. This suggests that factors other than cysteinyl groups contribute to the reduced antioxidative activity of apoE4.

Apolipoproteins B↗

Relationship of matrix metalloproteinases and their inhibitors to cartilage proteoglycan and collagen turnover: analyses of synovial fluid from patients with osteoarthritis.

OBJECTIVE: To determine the relationship between matrix metalloproteinases (MMPs), their inhibitors, and the turnover of matrix molecules in articular cartilage from patients with osteoarthritis (OA). METHODS: Synovial fluid samples were collected from the knees of 54 patients with OA. Radiographic evaluations and magnetic resonance imaging were performed on the knees of 34 OA patients to classify the stage of the disease. Biochemical analyses and immunoassays were used to measure the concentrations of MMP-1, MMP-3, tissue inhibitor of metalloproteinases 1 (TIMP-1), TIMP-2, the disaccharide of hyaluronic acid, the proteoglycan glycosaminoglycan disaccharides of chondroitin 4-sulfate (delta di-CS4) and chondroitin 6-sulfate (delta di-CS6), the 846 epitope on chondroitin sulfate of cartilage proteoglycan aggrecan (putative biosynthetic marker), the keratan sulfate (KS) epitope of aggrecan (putative degradation marker), and the C-propeptide of cartilage type II procollagen (CPII) (biosynthetic marker). RESULTS: The concentration of TIMP-1 was directly correlated with the levels of MMP-1 and MMP-3 (both were also correlated with each other), confirming earlier results. There was an inverse correlation between the delta di-CS6:delta di-CS4 ratio and the concentration of MMP-3. The level of delta di-CS6 was correlated with that of the KS epitope, and to a lesser degree, with that of the 846 epitope (the latter was also correlated with the level of delta di-CS4). The concentration of TIMP-1 correlated with that of the 846 epitope, whereas TIMP-2 levels correlated with those of CPII. There were significantly lower concentrations of delta di-CS6, delta di-CS4, the 846 epitope, and CPII in synovial fluid from patients with late-stage OA. CONCLUSION: These observations suggest a link between proteolysis and inhibitor concentrations in OA cartilage. Production of TIMPs appears to be individually linked to the synthesis of specific cartilage molecules. The reduction in the amount of cartilage-matrix structural components suggests that there is a measurable loss of cartilage in the late stages of the disease, as suggested previously. The resultant composition of the cartilage suggests that the loss may primarily involve "resident" molecules originally present in healthy cartilage.

Aged↗

Mapping of central D2 dopamine receptors in man using [11C]raclopride: PET with anatomic standardization technique.

D2 dopamine receptors are of interest in the pathophysiology of schizophrenia. For group comparisons of neuroreceptor distribution measured by PET on a pixel-by-pixel basis, an anatomic standardization technique is required. The aim of the present study is to build a database of normal D2 dopamine receptor distribution using [11C]raclopride and an anatomic standardization technique. In each subject, two PET measurements were performed with rapid bolus injection and with continuous infusion of [11C]raclopride. The radioactivity of the PET images were integrated in the time interval. Integrated images were normalized by the radioactivity of the cerebellum, providing a measure of the binding potential (BP) in each pixel. Each PET image was transformed into a standard brain anatomy using a Computerized Brain Atlas system. From the standardized PET images, the sample mean and the SD of the BP were calculated in each pixel. On the anatomically standardized average images for the both rapid bolus injection and continuous infusion, high BP was observed in the putamen and the caudate nucleus, whereas low BP was observed in the cerebral cortices. The BP for the thalamus and the substantia nigra were slightly higher than those for the cerebral cortices. This regional distribution is in good agreement with the distribution of D2 dopamine receptors known from in vitro studies. The anatomic standardization technique permits to build a database of the normal D2 dopamine receptor distribution in the living human brain. This technique can be applied for group comparisons on a pixel-by-pixel basis.

Adult↗

PET mapping of extrastriatal D2-like dopamine receptors in the human brain using an anatomic standardization technique and [11C]FLB 457.

The Computerized Brain Atlas (CBA) transforms PET images of individual subjects into a standard brain anatomy. We have previously applied this to PET images with [(11)C]raclopride and confirmed that the D2 dopamine receptors in the striatum can be evaluated accurately with a standard brain anatomy. There is growing evidence that extrastriatal D2 receptors, in spite of their low density, have pathophysiological significance for schizophrenia. We used the CBA to explore the extrastriatal distribution of D2 receptors in 13 healthy subjects using [11C]FLB 457, a substituted benzamide with very high affinity for D2 and D3 receptors. There was good agreement between the specific binding ratios from CBA quantification of standardized images and those from region-of-interest analyses of original images. The highest levels of binding were observed in the putamen and caudate nucleus, followed by the globus pallidus and nucleus accumbens. Besides the basal ganglia, the hypothalamus and nucleus ruber also showed high levels of binding. Intermediate levels were found in the substantia nigra, nucleus subthalami, amygdala, and thalamus. Interestingly, there was very heterogeneous binding among the thalamic nuclei. The anterior and mediodorsal nuclei showed relatively high binding. The cerebral cortices showed lower levels with significant regional differences. Binding was highest in the temporal cortex and hippocampus followed by the anterior cingulate gyrus, and the parietal and frontal cortices, but was lowest in the occipital cortex. The use of CBA for analysis of [11C]FLB 457 binding makes it possible to build a normal database for the extrastriatal D2 receptors in the living human brain. The heterogeneous distribution of D2 receptors provides an attractive opportunity for new research on the pathophysiology and drug treatment of schizophrenia.

Adult↗

Pharmacological properties of a novel gastrointestinal prokinetic benzamide selective for human 5-HT4 receptor versus human 5-HT3 receptor.

Binding properties of gastrointestinal prokinetic benzamides for both cloned human 5-hydroxytryptamine (5-HT)3 receptors and cloned human 5-HT4 receptors were examined and pharmacological properties of YM-53389{(+)-(S)-2-chloro-5-methoxy-4-[5-(2-piperidylmethyl)-1,2, 4-oxadiazol-3-yl]aniline monohydrochloride} were characterised in animals. Cisapride, renzapride and zacopride inhibited specific binding of [3H]ramosetron to cloned human 5-HT3 receptors, with Ki values of 684, 7.64 and 0.38 n m, respectively. YM-53389, however, slightly replaced that (Ki>10,000 n m). YM-53389, cisapride, renzapride and zacopride replaced specific binding of [3H]GR 113808 to cloned human 5-HT4 receptors, with Ki values of 54.6, 41.5, 115 and 373 n m, respectively. The potency for inhibitory effect of YM-53389 on 5-HT3 receptor-mediated contraction in the guinea-pig isolated colon was very low with pIC50 of 4.7. YM-53389 exerted 5-HT4 receptor-mediated relaxation in the carbachol-precontracted rat isolated oesophagus with pEC50 of 6.3. In mice, YM-53389 at 10 and 30 mg kg-1, s.c. significantly shortened whole gut transit time, in contrast to cisapride, renzapride and zacopride which were reported to delay that. YM-53389 had no significant effect on upper gastrointestinal propulsion at doses up to 30 mg kg-1, s.c. Based on these results, YM-53389 may surpass existing benzamides in facilitating lower intestinal propulsion and benefit patients with gastrointestinal disorders associated with impair of intestinal propulsion, such as constipation, based on the selective interaction with human 5-HT4 receptors vs human 5-HT3 receptors.

Animals↗

Hepatic resection for colorectal metastases: analysis of prognostic factors.

PURPOSE: Hepatic resection affords the best hope of survival for patients with colorectal carcinoma metastatic to the liver. However, recurrences are observed in about 60 percent of patients after curative hepatic resection. The purpose of this study was to examine the prognostic factors of patients undergoing curative hepatic resection for colorectal metastases. METHODS: Between April 1984 and September 1997, 168 patients underwent curative hepatic resection for colorectal metastases. The clinicopathologic factors studied for prognostic value were gender, age, primary site, nodal status of primary tumor, time of metastases, preoperative serum level of carcinoembryonic antigen, hepatic tumor size and distribution, number of metastases, type of hepatic resection, resection margin, presence of micrometastases in resected specimen and microscopic fibrous pseudocapsule between the hepatic tumor and surrounding hepatic parenchyma, nodal status of hepatoduodenal ligament, adjuvant regional chemotherapy, and perioperative transfusion. RESULTS: The overall survival was 42 percent at three years and 26 percent at five years, including a 3.5 percent 60-day surgical mortality rate. Thirty-one percent of patients had micrometastases located at a median distance of 3 mm from the metastatic tumor edge. Presence of microscopic fibrous pseudocapsule was observed in 28 percent of patients. Univariate and multivariate analyses showed that significant prognostic factors for survival were nodal status of primary tumor, number of metastases, resection margin, microscopic fibrous pseudocapsule, and adjuvant regional chemotherapy. CONCLUSIONS: We conclude that 1) hepatic resection is effective in select patients with colorectal metastases; 2) adequate resection margin and adjuvant regional chemotherapy can improve outcome; and 3) microscopic fibrous pseudocapsule may offer additional postoperative information as an independent prognostic factor.

Adult↗

The detection of chronic heart graft rejection by 31P NMR spectroscopy.

The usefulness of phosphorus-31 nuclear magnetic resonance spectroscopy (31P NMRS) for detecting heart graft rejection after transplantation has been investigated by several researchers, and it has thus been demonstrated to be a valid technique for detecting acute myocardial rejection. In this study, we investigated the value of 31P NMRS to assess chronic cardiac allograft rejection. Lewis rat hearts were transplanted into the femoral region of F-344 rat recipients which were treated with cyclosporine, 5mg/kg body weight, by a daily intramuscular injection for 30 days beginning on the day of transplantation. The control isografts employed Lewis donors and recipients not given cyclosporine. The ratios of phosphocreatine (PCr) to inorganic phosphate (Pi), beta-adenosine triphosphate (beta-ATP) to Pi, and PCr to beta-ATP were monitored using surface coil 31P NMRS. 31P NMRS was performed 3, 30, and 60 days after transplantation, and the degree of the rejection and arteriosclerosis of the coronary arteries were then assessed histologically. The PCr:Pi and beta-ATP:Pi ratios for the allografts demonstrated a significant decrease on postoperative day (POD) 60 from that on POD 30 (PCr:Pi, P < 0.001; beta-ATP:Pi, P < 0.01). Although a significant difference existed between the isografts and allografts on POD 60 (PCr: Pi, P < 0.01; beta-ATP:P, P < 0.01), no significant difference was found in the PCr:beta-ATP ratio between the allografts and the isografts. On POD 60, the allografts showed significant graft rejection and arteriosclerotic changes in the coronary arteries. These findings therefore demonstrated the effectiveness of 31P NMRS for detecting chronic graft rejection in a rat model.

Adenosine Triphosphate↗

Prediction of graft prolongation by mixed lymphocyte culture following anti-CD4 monoclonal antibody treatment among different donor-recipient combinations.

This study was conducted to examine whether mixed lymphocyte culture (MLC) could be used as a predictor of the efficacy of anti-CD4 monoclonal antibody (MAb) immunosuppression in vivo in a mouse model. C57BL/10 or BALB/c hearts were transplanted into C3H.He recipients. Anti-CD4 MAb administration prolonged graft survival, but there was a clear difference between the two donor-recipient combinations studied, the median survival time (MST) being >100 days in the C57BL/10 --> C3H group, and 17 days in the BALB/c --> C3H group. Anti-CD8 MAb prolonged the survival of C57BL/10 hearts slightly to a MST of 22 days, but the BALB/c hearts were rejected at control rates. Combining anti-CD4 and anti-CD8 antibody therapy prolonged the survival of C57BL/10 hearts indefinitely, but had little effect on the survival of BALB/c grafts, achieving an MST of only 24 days. Next, MLCs were performed in the presence and absence of the MAbs and compared with the graft survival data. The inhibition rates in the MLC, being the C3H lymph node cell responder, correlated well with graft survival. When three kinds of C3H responder cells, namely lymph node (LN) cells, T cells, and CD4+ cells, were examined to determine which was the most suitable for predicting graft survival, the MLC results showed that the responses of LN cells correlated most closely with graft outcome. In conclusion, MLC using LN cells as the responder is a useful tool for predicting allograft survival induced by anti-CD4 MAb therapy.

Animals↗

Complications associated with enteral nutrition using catheter jejunostomy after esophagectomy.

The present study was conducted on 78 patients, encountered over a 7-year period, who had a catheter-feeding jejunostomy placed at the time of thoracoabdominal esophagectomy for esophageal cancer. A broad-based attachment of the jejunal wall to the peritoneum at the place of entry of the catheter was used. Enteral nutrition was begun an average of 10 days after the operation, the caloric content was increased gradually, and the mean duration was 69 days. There were three patients who suffered from local skin erosion at the site of catheter entry, and seven who developed diarrhea and/or a feeling of abdominal fullness, but none of the patients showed any signs of peritonitis or ileus. The morbidity rates related to enteral nutrients and placement of the catheter jejunostomy were 8.9% and 3.8%, respectively. These findings demonstrate that a broad-based attachment of the jejunal wall to the peritoneum at the place of entry of the catheter is useful for preventing leakage or twisting of the jejunum, and for reducing the incidence and severity of the complications of catheter jejunostomy feeding.

Catheterization↗

Effects of scatter correction on regional distribution of cerebral blood flow using I-123-IMP and SPECT.

The transmission dependent convolution subtraction method which is one of the methods for scatter correction of SPECT was applied to the assessment of CBF using SPECT and I-123-IMP. The effects of scatter correction on regional distribution of CBF were evaluated on a pixel by pixel basis by means of an anatomic standardization technique. SPECT scan was performed on six healthy men. Image reconstruction was carried out with and without the scatter correction. All reconstructed images were globally normalized for the radioactivity of each pixel, and transformed into a standard brain anatomy. After anatomic standardization, the average SPECT images were calculated for scatter corrected and uncorrected groups, and these groups were compared on pixel by pixel basis. In the scatter uncorrected group, a significant overestimation of CBF was observed in the deep cerebral white matter, pons, thalamus, putamen, hippocampal region and cingulate gyrus as compared with scatter corrected group. A significant underestimation was observed in all neocortical regions, especially in the occipital and parietal lobes, and the cerebellar cortex. The regional distribution of CBF obtained by scatter corrected SPECT was similar to that obtained by O-15 water PET. The scatter correction is needed for the assessment of CBF using SPECT.

Adult↗

The effect of vitamin K and D supplementation on ovariectomy-induced bone loss.

This study was designed to assess the effect of vitamin K and D supplementation on ovariectomy-induced bone loss. Female Sprague-Dawley rats aged 8-9 months were ovariectomized (OVX) or sham operated and divided into five experimental groups: (1) ovariectomy (OVX), (2) OVX plus vitamin K supplementation, (3) OVX plus vitamin D supplementation, (4) OVX plus vitamin K and vitamin D supplementation, and (5) sham operation. The trabecular bone area was estimated by bone histomorphometry by microradiography and histological examination. Bone loss in OVX plus vitamin K and vitamin D group was significantly reduced at both 7 and 14 weeks compared with the OVX group. No significant bone loss in OVX plus vitamin K or OVX plus vitamin D groups was found. A similar effect of vitamin K and D supplementation on ovariectomy-induced bone loss was recognized in histological examination. Our findings indicate that vitamins K and D may have a synergistic effect on reducing bone loss. This is valuable information for the treatment of bone loss in postmenopausal women with osteoporosis.

Animals↗