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Biomedical subjects

R Matsushita

Publications and source records attributed to R Matsushita.

At least 19 recordsLinked to original sources
PubMed2006

Uptake of deuterium by dead leaves exposed to deuterated water vapor in a greenhouse at daytime and nighttime.

Dead leaves were exposed to deuterated water vapor (D(2)O) as a substitute of tritiated water (HTO) in a greenhouse at daytime and nighttime to examine uptake and release of tritium by dead leaves because they cover a wide area of the forest floor and are therefore a major target material to be exposed when HTO is atmospherically derived to the forest. The dead cedar needles showed faster uptake and faster release rates during and after the exposure than the fresh ones, and the equilibrium concentration of the dead cedar needles was about two times higher than the fresh ones, indicating a quick response and a high buffering potential of dead leaves. The relation between uptake of D(2)O and number of stoma was examined for dead deciduous leaves; the species with larger number of stoma accumulated more D(2)O at the daytime and nighttime exposures. However, drying of the dead leaves suppressed D(2)O uptake greatly at daytime, suggesting stomata's opening and closing controls the D(2)O uptake of dead leaves.

Cryptomeria↗
PubMed2001

Kinetic phenotypic diagnosis of N-acetylation polymorphism in patients based on ratio of urinary metabolites of salicylazosulfapyridine.

We found that N-acetylation polymorphism can be evaluated from the disposition kinetics of sulfapyridine (SP) and 5-aminosalicylic acid (5-ASA) and their acetylated metabolites generated by N-acetyltransferase (NAT2) after oral administration of salicylazosulfapyridine (SASP). In 126 Japanese subjects, the homozygote of NAT2*4 was the most frequent (40%), followed by heterozygotes of NAT2*4 and mutant genes (28% NAT2*4/*6A, 15% NAT2*4/*7B, and 2% NAT2*4/*5B). Combinations of mutant genes accounted for 16%. When the relationship between the molar ratio of N-acetyl-SP (Ac-SP)/SP or N-acetyl-5-ASA(Ac-5-ASA)/5-ASA in serum and five genotypes of polymorphic NAT2* was examined in patients who received multiple doses of SASP, the molar ratios of Ac-SP/SP, rather than Ac-5-ASA/5-ASA tended to decrease according to the classification of genotype. We calculated the pharmacokinetic parameters in healthy subjects with various genotypes of polymorphic NAT2* after a single p.o. administration of SASP, according to a model of the SP metabolic pathways. The molar ratios of Ac-SP/SP in serum and urine were simulated using these parameters, and the molar ratio of Ac-SP/SP in urine at 4 days after the first administration could be categorized into ranges that were specific to various NAT2* genotypes. Thus, we were able to predict the N-acetylation polymorphic genotypes of patients by measuring the molar ratio of Ac-SP/SP in urine, after administration of SASP.

Acetylation↗
PubMed2001

A new halogenated antidiabetic vanadyl complex, bis(5-iodopicolinato)oxovanadium(IV): in vitro and in vivo insulinomimetic evaluations and metallokinetic analysis.

A new vanadyl complex, bis(5-iodopicolinato)oxovanadium(IV), VO(IPA)2, with a VO(N2O2) coordination mode, was prepared by mixing 5-iodopicolinic acid and VOSO4 at pH 5, with the structure characterized by electronic absorption, IR, and EPR spectra. Introduction of the halogen atom on to the ligand enhanced the in vitro insulinomimetic activity (IC50 = 0.45 mM) compared with that of bis(picolinato)oxovanadium(IV) (IC50 = 0.59 mM). The hyperglycemia of streptozotocin-induced insulin-dependent diabetic rats was normalized when VO(IPA)2 was given by daily intraperitoneal injection. The normoglycemic effect continued for more than 14 days after the end of treatment. To understand the insulinomimetic action of VO(IPA)2, the organ distribution of vanadium and the blood disposition of vanadyl species were investigated. In diabetic rats treated with VO(IPA)2, vanadium was distributed in almost all tissues examined, especially in bone, indicating that the action of vanadium is not peripheral. Vanadyl concentrations in the blood of normal rats given VO(IPA)2 remain significantly higher and longer than those given other complexes because of its slower clearance rate. VO(IPA)2 binds with the membrane of erythrocytes, probably owing to its high hydrophobicity in addition to its binding with serum albumin. The longer residence of vanadyl species shows the higher normoglyceric effects of VO(IPA)2 among three complexes with the VO(N2O2) coordination mode. On the basis of these results, VO(IPA)2 is indicated to be a preferred agent to treat insulin-dependent diabetes mellitus in experimental animals.

Adipose Tissue↗
PubMed2001

Effect of meropenem on disposition kinetics of valproate and its metabolites in rabbits.

PURPOSE: We investigated the effect of meropenem (MEPM) on the disposition kinetics of valproate (VPA) and its metabolites in rabbits. METHODS: Rabbits were given 75 mg/kg VPA intravenously with or without 300 mg/kg MEPM. RESULTS: The plamsa total clearance of VPA was significantly increased to about 1.5 times the control (6.09 mL/min/kg vs. 4.28 mL/min/kg) by MEPM (P < 0.05). The values of the area under the plasma concentration-time curve (AUC) of 2-en-VPA, a product of beta-oxidation, and VPA-glucuronide (VPA-G) were significantly decreased to about 55% and 78% of the control, respectively (P < 0.05). The cumulative urinary excretions of VPA in the control and MEPM-treated groups were 0.54% and 0.62% of the dose, respectively, whereas those of VPA-G were 45.6% and 62.5%, respectively. The urinary excretion of VPA-G was significantly increased by MEPM (P < 0.05). Further, in the case of 33.8 mg/kg VPA-G administered intravenously the AUC value of VPA-G was unchanged by MEPM, whereas that of the generated VPA was significantly decreased to about half of the control. CONCLUSIONS: The increase of the total clearance of VPA caused by MEPM appears to be a consequence of increased renal clearance of VPA-G, as well as suppression of VPA-G hydrolysis in the liver.

Animals↗
PubMed2001

Synergistic effect of indomethacin with adriamycin and cisplatin on tumor growth.

In this study, we have examined the antitumor effect of combined administrations of indomethacin (IND) with chemotherapeutic drugs on tumor growth. Colon 26 clone 20 (C20) cells and monocyte chemotactant protein-1 (MCP-1) transfected C20 cells (C20betaA-2-1) were used and these cells were inoculated into the footpad of BALB/c mice. At day 1 after tumor inoculation, treatment with 0.001% IND via the drinking water was commenced. At days 4, 6, and 8, adriamycin or cisplatin was administered intravenously at a dose of 5 mg/kg or intraperitoneally at a dose of 2 mg/kg, respectively. Although IND, adriamycin and cisplatin only partially reduced the growth of the C20 tumors after treatment with each drug on its own, a marked synergistic effect was observed when they were given in combination. A synergistic effect between IND and cisplatin on C20betaA-2-1 was also observed. However, IND itself showed no suppression of C20betaA-2-1 tumor growth. These results suggest that combination of indomethacin with chemotherapeutic drugs could be an effective form of cancer chemotherapy. The observed effects may be dependent on the expression of MCP-1.

Adenocarcinoma↗
PubMed2000

Comparison of various biochemical measurements with bone mineral densitometry and quantitative ultrasound for the assessment of vertebral fracture.

We have retrospectively studied postmenopausal elderly Japanese women (n = 288; age range, 60-75 years, 65.8 +/- 4.5 [mean +/- SD]) for the evaluation of biochemical measurements in assessment of bone mass and vertebral fracture, comparing with several bone mineral measurements and quantitative ultrasound (QUS) measurement. Several biochemical parameters [red cell count (RBC), hemoglobin (HB), albumin (ALB), and cholesterol (CHO)] positively correlated with bone mass parameters, but only serum cholesterol showed association with the presence of vertebral fracture. Urinary deoxypyridinoline (DPYD) and n-telopeptide (NTx) showed moderate negative correlation with bone mass parameters, and DPYD showed association with vertebral fracture. All bone mineral measurements (lumbar spine, total body, femoral neck by DXA, calcaneal bone by SXA, distal radius by pQCT) and QUS measurement (os calcaneus by two different QUS machines) showed a higher odds ratio and high chi2 value in logistic regression analysis for association with vertebral fracture. Thus, bone mass measurement is the principal method for assessment of fracture risk, and biochemical measurement should be used for motivation of further bone mass measurement. In biochemical measurements, measurement of serum cholesterol is cheap and easy, and thus might have an advantage, although further study is necessary.

Absorptiometry, Photon↗
PubMed2000

Hepatocyte growth factor/scatter factor enhances the thrombopoietin mRNA expression in rat hepatocytes and cirrhotic rat livers.

BACKGROUND: Although thrombopoietin (TPO) is mainly produced in the liver, the regulatory mechanism of TPO gene expression in hepatocytes remains unclear. The role of TPO in thrombocytopenia associated with liver cirrhosis has not been identified. METHODS: We examined the effects of various growth factors and cytokines on TPO mRNA expression in adult rat hepatocytes in primary cultures using a semiquantitative reverse transcription-polymerase chain reaction assay. RESULTS: Among them, only hepatocyte growth factor/scatter factor (HGF/SF) enhanced TPO mRNA expression; other growth factors (epidermal growth factor and transforming growth factor-beta) and cytokines (erythropoietin, granulocyte-colony stimulating factor, granulocyte-macrophage-colony stimulating factor, interleukin (IL)-3, IL-6 and interferon-gamma) did not. Next, we examined TPO mRNA expression in the livers of rats with CCl4-induced cirrhosis, the effects of HGF/SF on hepatic TPO mRNA expression and peripheral platelet and bone marrow megakaryocyte counts in the cirrhotic rats. In the cirrhotic rats, both the peripheral platelet count and TPO mRNA expression in the livers were markedly decreased compared with those of the normal rats. The administration of HGF/SF to the cirrhotic rats stimulated TPO mRNA expression in the livers and resulted in significant increases of peripheral platelets and bone marrow megakaryocytes. CONCLUSIONS: These results suggest that HGF/SF is a possible regulatory factor for TPO gene expression and that HGF/SF increases platelet production through an enhancement of TPO mRNA expression in the livers of cirrhotic rats.

Animals↗
PubMed1999

Multielement compositions of marine phytoplankton samples from coastal areas of Japan by instrumental neutron activation analysis.

Phytoplankton samples were collected during spring bloom of diatoms from three coastal areas of Japan using a NORPAC P-25 net (25-micron opening) with a NGG52 prenet (335-micron opening), and 25 major and trace elements have been analyzed by INAA. Concentration ranges of analyzed phytoplankton samples are much wider than the concentration ranges compiled by Bowen (1979) except for As, and data of marine phytoplankton samples for Br, Sb, Hf, Sc, La, Ce, Sm, and Eu were not included in the compilation. The 25 analyzed elements have been categorized into three groups: elements showing positive correlation with Br, positive correlation with Al, and no positive correlation with Br or Al. The marine phytoplankton samples have been plotted on a Masuzawa-Koyama-Terazaki (MKT) plot and it proved that the MKT plot is applicable to marine phytoplankton samples.

Japan↗
PubMed1999

Comparison of bone mineral density at various skeletal sites with quantitative ultrasound parameters of the calcaneus for assessment of vertebral fractures.

This study investigated the role of quantitative ultrasound (QUS) for evaluation of fracture risk in comparison with bone mineral density (BMD) measurement. Our subjects were postmenopausal Japanese women (n = 260; age, 67 +/- 6.1 years) who were examined for bone densitometry, QUS, and spinal X-ray examination at our department between 1992 and 1996. The subjects were categorized into three groups by the number of atraumatic fractured vertebrae: NF, no vertebral fractures: F1, one vertebral fracture; F2, two or more vertebral fractures. We compared the measured parameters to determine their association with the number of fractured vertebrae. Differences among groups were compared and analyzed by Student's t-test. Odds ratios were also calculated after age adjustment, as well as age and lumbar or calcaneal parameters. Between NF and F1, lumbar BMD and BMD of the Ward's triangle showed more significant differences than other values, while between F1 and F2, whole-body BMD and QUS parameters showed more significant differences. Lumbar BMD also showed the highest age-adjusted odds ratio in differentiating F1 from NF. Although QUS parameters showed no power to differentiate between NF and F1, these values showed higher odds ratios than other measurements for discriminating between F1 and F2. Adjustment for bone density did not totally abolish the association between QUS parameters and vertebral fracture. Additionally, the combination of lumbar BMD and QUS ("stiffness") clearly showed a high power to discriminate NF from F1 + F2. In conclusion, we showed that QUS measurement is effective in evaluating fracture risk in advanced osteoporosis, while lumbar dual X-ray absorptiometry is effective in evaluating risk in early osteoporosis.

Aged↗
PubMed1998

Usefulness of adenosine triphosphate-atropine stress echocardiography for detecting coronary artery stenosis.

There have been few studies on adenosine triphosphate (AT) stress echocardiography. The AT stress test may have fewer adverse effects than the adenosine stress test. The addition of atropine to AT echocardiography may enhance the sensitivity for detection of coronary artery disease (CAD). The purpose of this study was to determine the utility of AT-atropine echocardiography for detection of CAD. The group studied consisted of 112 patients with suspected CAD. Sixty-one patients did not have a history of prior myocardial infarction (group I) and 51 patients did (group II). AT was infused intravenously at 180 microg/kg/min for 14 minutes. Atropine (0.25 mg intravenously, repeated up to maximum total dose of 1 mg) was administered starting after 8 minutes of AT infusion. Ischemic response was defined as new or worsening wall motion abnormality occurring during the infusion. The sensitivity and specificity for detection of CAD were assessed using the representative echocardiograms during single AT infusion and AT-atropine infusion. Sixty-two patients had CAD. Fifty-eight patients (52%) developed minor side effects that resolved promptly. The rate-pressure product (10(3)/mm Hg beats/min) was significantly increased at 12 minutes of infusion (12.4+/-3.2) compared with that at baseline (9.1+/-2.3) and that at 6 minutes of infusion (9.4+/-2.1). The sensitivity for detection of CAD was 45% for AT echocardiography and 74% for AT-atropine echocardiography. The specificity was 94% for AT echocardiography and 90% for AT-atropine echocardiography. The sensitivity and specificity of AT-atropine echocardiography was 78% and 93%, respectively, in group I, and 70% and 86%, respectively, in group II. In conclusion, AT-atropine stress echocardiography seems to be well tolerated, safe, and useful for detection of CAD.

Adenosine Triphosphate↗
PubMed1998

Relationship between skeletal uptake of 99mTc-HMDP and bone mineral density in elderly women.

The relationship between bone mineral density in elderly women and the pattern of skeletal uptake of 99mTc-HMDP, especially in regard to skull uptake, was investigated. The whole-body skeletal uptake (WBSU) and whole-body skeletal tracer distribution patterns were studied in 86 disease-free women on bone scintigraphy with 99mTc-hydroxy-methylene-diphosphonate (HMDP). Bone scans were quantified by setting regions of interest (ROI) and bone mineral density (BMD) was assessed by dual-energy X-ray absorptiometry in all patients. WBSU and the skeletal distribution pattern were compared with bone mineral densities of the entire skeleton as well as selected regions. WBSU was high in the elderly and negatively correlated with regional bone mineral densities (r = -0.403 to -0.534). Among the regions, uptake by the skull increased with age more than in other regions in women and had the highest negative correlation with the bone mineral density. The skull uptake correlated negatively with total body BMD (r = -0.583) and with lumbar BMD (r = -0.561, p < 0.0001). Our results show that increased radionuclide uptake in bone scintigraphy, especially skull uptake was associated with decreased bone mineral density in elderly women, so that, increased skull uptake in elderly women would be a scintigraphic sign of post-menopausal or senile osteopenia.

Absorptiometry, Photon↗
PubMed1998

Synergistic antitumor interaction of human monocyte chemotactant protein-1 gene transfer and modulator for tumor-infiltrating macrophages.

PURPOSE: In order to evaluate the possibility of synergistic antitumor gene therapy by the gene delivery of monocyte chemotactant protein-1 (MCP-1/MCAF/IE), the effect of a biological response modulater for macrophages on tumor progression of gene transfected tumor cells was studied. METHODS: Cachexia-inducing adenocarcinoma cells (cell line colon 26, clone 20) were transfected with either a control plasmid or MCP-1 cDNA. RESULTS: The production of MCP-1 reached 70-80 ng/ml in vitro when transfectant cells were cultured at a cell density of 1 x 10(5) cells/ml for 3 days. Transfection of MCP-1 cDNA did not affect the growth rate in vitro. Also, MCP-1-transfectants formed tumors after intra-footpad inoculation similar in size to the parental cells. The number of infiltrating macrophages in the primary tumor of the transfectant rapidly increased from the 3rd to 5th day after inoculation as revealed by immunohistochemical staining using an antibody against mouse macrophages. An earlier, greater, but no longer-lasting increase in tumor-infiltrating macrophages was induced in tumors by MCP-1 transfection was compared to that induced by the parent cells. On the 10th day after the inoculation, the tumor-infiltrating macrophages in mice inoculated MCP-1 transfectants were decreased to a level similar to that of the parent cells. Groups of mice were treated intraperitoneally with LPS at different times after the inoculation. Tumor cells producing high levels of MCP-1 were significantly lysed by macrophages treated with LPS, whereas parental or control transfected cells were not. Conclusions. Combination immunotherapy can provide a rationale for the application of MCP-1 treatment to increase immunological responses to cancer.

Adenocarcinoma↗
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↗
PubMed1997

Transesophageal Doppler echocardiographic assessment of systolic and diastolic coronary blood flow velocities at baseline and during adenosine triphosphate-induced coronary vasodilation in chronic aortic regurgitation.

Few reports exist on the changes in systolic and diastolic coronary flow velocities (CFVs) at baseline and during coronary vasodilation in patients with chronic aortic regurgitation (AR). We examined the left anterior descending CFVs in 21 patients with AR (11 patients with mild AR and 10 patients with moderate to severe AR), 9 patients without AR (no AR group), and 6 patients who had undergone surgery for moderate to severe AR (postoperation group) with transesophageal Doppler echocardiography. Adenosine triphosphate (ATP) was infused into a peripheral right arm vein at four different doses (35, 70, 100, and 140 micrograms/kg/min). Coronary flow velocity response in systole and diastole was calculated as the ratio of systolic peak and mean and diastolic peak and mean CFVs during maximal ATP infusion to those at baseline. The systolic peak and mean CFVs and the diastolic peak and mean CFVs at baseline were significantly increased in the moderate to severe group compared with those in the other groups (p < 0.05, respectively). Systolic and diastolic CFVs were significantly increased during ATP infusions in the four groups. No significant differences of systolic and diastolic CFVs were observed among the four groups during maximal ATP infusion. The coronary flow velocity response calculated from the peak and mean diastolic CFVs were significantly decreased in the moderate to severe group (1.6 +/- 0.3 and 1.7 +/- 0.4) compared with those in the other three groups (3.6 +/- 0.7 and 3.2 +/- 1.1 in the no AR group, 2.6 +/- 0.6 and 2.5 +/- 0.4 in the mild group, and 2.5 +/- 0.7 and 2.4 +/- 0.6 in the postoperation group) (p < 0.05, respectively). In conclusion, the systolic and diastolic left CFVs at baseline appeared to be significantly increased in patients with moderate to severe chronic AR. However, the velocities during coronary vasodilation by ATP were equal to those in other groups, resulting in a decrease of coronary flow velocity response in systole and diastole.

Adenosine Triphosphate↗
PubMed1997

Diagnostic validity of bone metabolic markers for bone metastasis.

We measured bone resorption markers in tumor patients with and without bone metastases and evaluated the diagnostic validity of these biochemical parameters in the diagnosis of neoplastic bone involvement. On the basis of radiography and bone scintigraphy findings, subjects were divided into 3 groups, 83 patients without bone metastases (META(-)), 22 patients with 1 or 2 bone metastases (META(+)) and 22 patients with more than 3 bone metastases (META(++)). Among the biochemical markers, urinary pyridinoline (PYR), circulating C-terminal telopeptide of type I collagen (ICTP) and urinary N-terminal telopeptide of type I collagen (NTx) were especially sensitive and specific and increased significantly not only in META(++) but also even in META(+). The efficacy of several bone metabolic markers in differentiating between patients with and without bone metastases was evaluated by receiver-operating characteristic (ROC) analysis, and PYR, ICTP and NTx were proved to have high diagnostic validity (area under the ROC curve; 0.75 for PYR, 0.77 for ICTP and 0.77 for NTx). Furthermore, their odds ratios showed significantly high values for both META(+) and META(++)(to META(++); 7.91 for PYR, 5.33 for ICTP and 5.70 for NTx). On the other hand, urinary deoxypyridinoline (DPYR) and serum total alkaline phosphatase (ALP) showed relatively low sensitivities, the odds ratio of ALP in particular being insignificant. In conclusion, several bone metabolic markers were proved to be useful in the diagnosis of bone metastases in patients with malignancies, particularly PYR, ICTP and NTx had rather high diagnostic validities among all markers examined in this study.

Adult↗
PubMed1996

Transesophageal Doppler echocardiographic assessment of left coronary blood flow velocity in chronic aortic regurgitation.

Assessment of systolic and diastolic coronary blood flow velocities (FVs) in patients with aortic regurgitation (AR) has remained a clinical challenge. We recorded left anterior descending coronary blood FV in 21 patients with chronic AR an in 6 control subjects using transesophageal pulsed Doppler echocardiography. In 7 patients FV was measured 4.0 +/- 5.2 months after aortic valve replacement. Peak and mean FVs during systole and diastole and systolic/diastolic ratios of these FVs were determined. Left ventricular (LV) mass index was calculated by means of standard M-mode echocardiography. In patients with severe AR, peak and mean systolic FVs were significantly increased (34 +/- 8 cm/sec and 21 +/- 6 cm/sec, respectively) compared with FVs in the control group (15 +/- 4 and 12 +/- 3 cm/sec, respectively) and in patients with mild AR (17 +/- 3 cm/sec and 13 +/- 2 cm/sec, respectively). Peak and mean systolic FVs were also significantly increased in severe AR (54 +/- 13 cm/sec and 33 +/- 9 cm/sec, respectively) compared with FVs in the control (30 +/- 8 cm/sec and 21 +/- 5 cm/sec, respectively) and mild AR groups (30 +/- 5 cm/sec and 21 +/- 4 cm/sec, respectively). Peak systolic and diastolic FVs were correlated significantly with LV mass index (r = 0.72 and r = 0.73, respectively). Systolic and diastolic FVs and LV mass index were significantly decreased, normalized or both after aortic valve surgery. In conclusion, LV mass seems to have an effect on the significantly increased systolic and diastolic left coronary blood FV pattern in patients with chronic, severe AR. Increased systolic and diastolic FV appears to be normalized in the late period after surgery.

Adult↗