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Biomedical subjects

M Wada

Publications and source records attributed to M Wada.

At least 109 records · Page 6Linked to original sources
PubMed2000

Alu-associated interstitial deletions and chromosomal re-arrangement in 2 human multidrug-resistant cell lines.

Previous studies have shown that gene re-arrangements play a significant role in tumorigenesis. Gene re-arrangements involving the human multidrug resistance-1 (MDR1) gene have been identified as a mechanism for MDR1 over-expression in human malignant cells. In 2 multidrug-resistant human cancer sublines with high levels of MDR1 and P-glycoprotein (MCF7/TX400 and S48-3s/Adr10), hybrid mRNAs containing sequences from MDR1 and an unrelated gene have previously been identified. To characterize and determine the site of the re-arrangements resulting in generation of hybrid mRNAs, we first constructed a lambda phage library extending over a contiguous genomic region of 100 kb and containing the region upstream of MDR1. In MCF7/TX400 cells, homologous recombination was observed involving an Alu repeat 80 kb upstream of the MDR1 gene, with a 79 bp intra-Alu deletion flanked by chi-like sequences at the re-arrangement junction. By contrast, non-homologous recombination was observed in S48-3s/Adr10 cells with Alu repeats near the junction sequence. While the specific features of the breakpoints appear to be different, Alu repeats might be involved in both gene re-arrangements. The gene re-arrangements at or near the Alu sequence should be regarded as potentially involved in the transcriptional activation of human MDR1.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

GH induced lipolysis stimulation in 3T3-L1 adipocytes stably expressing hGHR: analysis on signaling pathway and activity of 20K hGH.

We have constructed a cell line of 3T3-L1 which can efficiently express human GHR (3T3-L1-hGHR) after differentiation to adipocytes. The expressed hGHR was detected as two bands with approximate molecular sizes of 120K by Western analysis using hGHR specific monoclonal antibody. Maximum lipolytic activity induced by hGH in the 3T3-L1-hGHR was enhanced 10-fold as compared to that in 3T3-L1, suggesting that expressed hGHR is functionally active. Comparative analysis using bGH and hGH revealed that 70% of lipolysis stimulation by 1-10 ng/ml hGH could be attributed to hGHR-mediated response. Analyses on inhibition and phosphorylation of signaling molecules suggested that GH-induced lipolysis stimulation is dependent on gene expression and not mediated through PKA-, PKC-, PLA-, PLC-, nor MAPK-pathway but possibly through JAK-STATs pathway. Duration of STAT5 activation by hGH continued up to 48 h. We also revealed that 22 K hGH isoform, 20K hGH which has been reported as a weaker agonist for GH-induced lipolysis stimulation, possesses equipotent activity and shows stronger action in the presence of hGHBP as compared to 22 K hGH. Taken together we conclude that the hGH-induced lipolysis was not mediated through MAP-, PKA-, PKC-, nor PLA-pathway but might be mediated through STAT pathway and that 20K hGH might show higher lipolytic activity than 22 K hGH in adipose tissue that produces a large amount of GHBP.

3T3 Cells↗
PubMed2000

Effect of the photocatalytic activity of TiO(2) on plasmid DNA.

We investigated the photodynamic DNA strand-breaking activity of TiO(2). A solution of super-coiled pBR 322 DNA was irradiated with 5 J/cm(2) of UVA in the presence of TiO(2) and the products were analyzed by using gel electrophoresis. The ratio of open-circular DNA to super-coiled circular DNA was calculated from the resulting peak areas as a DNA strand-breaking index (SBI). The SBI of anatase-structure TiO(2) (band gap=3.23 eV) was greater than that of rutile structure (band gap=3.06 eV), and the level of SBI correlated with the photocatalytic activity for degradation of 2-propanol. The inhibitory effects of active oxygen scavengers, including DMSO, glutathione and histidine, on the DNA strand-breaking activity were examined. All of the scavengers except ascorbic acid showed inhibitory effects, as did several polyhydric alcohols including mannitol, a well-known hydroxyl radical scavenger. These results suggest that the photodynamic DNA strand-breaking activity of TiO(2) is due to active oxygen species, especially hydroxyl radicals. Polyhydric alcohols showed an inverse correlation between the inhibitory effect on DNA strand-breaking activity and the octanol/water partition coefficient (logP).

Ascorbic Acid↗
PubMed2000

Angiotensin AT1 receptors in the preoptic area negatively modulate the cardiovascular and ACTH responses induced in rats by intrapreoptic injection of prostaglandin E2.

We previously reported that brain angiotensin II type 2 (AT2) receptors contribute to the hyperthermia induced by intrahypothalamic (intrapreoptic (i.p.o.)) administration of prostaglandin E2 (PGE2) in rats. The present study was carried out to investigate the role of angiotensin II (ANG II) receptors in the cardiovascular and adrenocorticotropic hormone (ACTH) responses induced in rats by i.p.o. injection of PGE2. PGE2 (100 ng) produced marked increases in blood pressure, heart rate, and plasma ACTH concentration. These changes were significantly enhanced by i.p.o. treatment with an AT1-receptor antagonist, losartan, while an AT2-receptor antagonist, CGP 42112A, had no effect. In contrast, losartan, but not CGP 42112A, reduced the pressor and ACTH responses to i.p.o. injection of a large dose of "exogenous" ANG II (25 ng). These results suggest that while "endogenous" ANG II exerts inhibitory effects on both the cardiovascular and the ACTH responses to i.p.o. PGE2 by way of preoptic AT1-receptors, a large dose of exogenous ANG II produces effects opposite to those induced by the endogenous ANG II that is released locally and in small amounts by i.p.o. PGE2.

Adrenocorticotropic Hormone↗
PubMed2000

Characteristics of 49 patients who survived for 5 years following radical radiation therapy for non-small cell lung cancer: the potential for cure.

PURPOSE: To investigate the long-term curative potential of radical radiation therapy (RT) for non-small cell lung cancer (NSCLC) by studying characteristics of patients from a large prospective database who survived >5 years after RT, and by analyzing survival beyond 5 years. METHODS AND MATERIALS: Five-year survivors were identified from a database containing information on 488 patients given radical RT following presentation to the Peter MacCallum Cancer Institute with NSCLC between 1984 and 1990. Additional data were obtained from case notes of survivors. RT was computed tomography (CT)-planned, conventionally-fractionated, and given without chemotherapy. RESULTS: Actuarial survival for 49 5-year survivors was 65% at 10 years. Five 5-year survivors had documented disease progression within the first 5 years and subsequently died. Of 44 patients free-from-progression (FFP) at 5 years, an estimated 81% remained FFP in the second 5 years. Age and histology were not significant prognostic factors, and only 22 patients (4.5%) had weight loss >10%. For 277 patients who had not undergone thoracotomy, median RT dose was 60 Gy and survival at 5 and 10 years was 7% and 3%, respectively. For 207 patients who received radical RT post-thoracotomy, median dose was 60 Gy and survival at 5 and 10 years was 24% and 18%, respectively. Five-year survivors of post-thoracotomy RT had been treated for gross residual disease (n = 10), positive-margin (n = 6), or probable microscopic residual disease (n = 17). Failure to regain ECOG performance status = 0 post-thoracotomy was associated with reduced survival (p<0.0012). FFP in the second 5 years was superior for patients who had postoperative radiotherapy (90%) compared to patients without thoracotomy (62%, p = 0.008). CONCLUSION: Most patients FFP >5 years after radical RT for NSCLC remained FFP in the following 5 years and were apparently cured. RT alone can cure small but significant numbers of patients. Long-term results of combined chemotherapy/RT protocols, which are associated with increased median survival, are awaited for comparison.

Aged↗
PubMed2000

Quantification of methamphetamine, amphetamine and enantiomers by semi-micro column HPLC with fluorescence detection; applications on abusers' single hair analyses.

Achiral and chiral semi-micro column high-performance liquid chromatographic methods with fluorescence detection to determine methamphetamine and amphetamine in human hair are described. These compounds were extracted into 5% trifluoroacetic acid (TFA) in methanol, derivatized with 4-(4,5-diphenyl-1H-imidazol-2-yl)-benzoyl chloride and separated either on a 250 x 1.5 mm i.d. octadecyl-silane (ODS) or a 150 x 2 mm i.d. OD-RH column. Linear calibration curves extending over a wide range of concentration that covers the practical samples were obtained for amphetamine, methamphetamine and their enantiomers (r = 0.999). Resolution values for amphetamine and methamphetamine enantiomers were 3.4 and 1.1, respectively. Intra- and inter-day variations of both the methods were not larger than 8.9% expressed as relative standard deviations (n >/= 5). The limits of detection at a signal-to-noise ratio of 3 obtained by both the methods were in the range of 1.0-4.7 fmol/5 microL injection with the achiral method being more sensitive. Abusers' hair samples were analyzed by the two methods and only the S(+)-enantiomers were found in eight Japanese abusers' hair samples. The achiral method was used to study the concentrations of these compounds in single black and white hair strands of abusers.

Amphetamine↗
PubMed2000

Intracellular chloroplast photorelocation in the moss Physcomitrella patens is mediated by phytochrome as well as by a blue-light receptor.

The light-induced intracellular relocation of chloroplasts was examined in red-light-grown protonemal cells of the moss Physcomitrella patens. When irradiated with polarized red or blue light, chloroplast distribution in the cell depended upon the direction of the electrical vector (E-vector) in both light qualities. When the E-vector was parallel to the cross-wall (i.e. perpendicular to the protonemal axis), chloroplasts accumulated along the cross-wall; however, no accumulation along the cross-wall was observed when the E-vector was perpendicular to it (i.e. parallel to the protonemal axis). When a part of the cell was irradiated with a microbeam of red or blue light, chloroplasts accumulated at or avoided the illumination point depending on the fluence rate used. Red light of 0.1-18 W m-2 and blue light of 0.01-85.5 W m-2 induced an accumulation response (low-fluence-rate response; LFR), while an avoidance response (high-fluence-rate response; HFR) was induced by red light of 60 W m-2 or higher and by blue light of 285 W m-2. The red-light-induced LFR and HFR were nullified by a simultaneous background irradiation of far-red light, whereas the blue-light-induced LFR and HFR were not affected at all by this treatment. These results show, for the first time, that dichroic phytochrome, as well as the dichroic blue-light receptor, is involved in the chloroplast relocation movement in these bryophyte cells. Further, the phytochrome-mediated responses but not the blue-light responses were revealed to be lost when red-light-grown cells were cultured under white light for 2 d.

Bryopsida↗
PubMed2000

Effect of static magnetic fields on bacteria: Streptococcus mutans, Staphylococcus aureus, and Escherichia coli.

Biological effect of static magnetic field was investigated by using ferrite magnets to conduct a magnetic field exposure experiment on three species of bacteria: Streptococcus mutans, Staphylococcus aureus, and Escherichia coli. The effects were evaluated by culturing the bacteria and determining their growth rate, the maximum numbers of bacteria, and [3H]-thymidine incorporation. The results showed that the ferrite magnet caused strength-dependent decreases in the growth rate and growth maximum number of bacteria for S. mutans and S. aureus when cultured under anaerobic conditions, but that their growth was not inhibited under aerobic conditions. In addition, [3H]-thymidine was added after culturing each of the species of bacteria for 18 h. After that, culture was continued until 24 h, and changes in [3H]-thymidine incorporation were investigated. But no effect of the magnetic fields was detected. These findings suggested that oxygen related to growth the cases of S. mutans, S. aureus. However, no growth effects were detected on E. coli cultures.

Journal Article↗
PubMed2000

Supplementation of orotic acid to the casein, but not to egg protein, soy protein, or wheat gluten diets, increases serum ornithine carbamoyltransferase activity.

Effects of dietary supplementation of orotic acid to a diet containing the casein protein were compared with diets containing egg protein, soy protein, or wheat gluten on lipid levels in the liver and serum and activities of ornithine carbamoyltransferase (OCT) and alanine aminotransferase in the serum of rats. We found that supplementation of orotic acid to each diet increased the contents of the liver total lipids, triacylglycerol, and phospholipids compared with those not supplemented. The contents of liver total lipids, triacylglycerol, cholesterol, and phospholipids in rats fed the casein diet were significantly higher than those of rats fed the other three diets when orotic acid was supplemented. The levels of triacylglycerol, cholesterol, and phospholipids in the serum of rats fed the casein diet were markedly decreased by addition of orotic acid. The supplementation of orotic acid significantly increased the activities of both serum OCT and alanine aminotransferase in rats fed the casein diet, but not in rats fed the other diets. In conclusion, liver lipid accumulation induced by dietary orotic acid depends on the type of dietary protein. The enhancement of serum OCT activity may result from liver lipid accumulation in rats fed the casein diet supplemented with orotic acid, demonstrating hepatic damage.

Journal Article↗
PubMed2000

Daily intermittent decreases in serum levels of parathyroid hormone have an anabolic-like action on the bones of uremic rats with low-turnover bone and osteomalacia.

The calcium receptor agonist (calcimimetic) compound NPS R-568 causes rapid decreases in circulating levels of parathyroid hormone (PTH) in rats and humans. We hypothesized that daily intermittent decreases in serum PTH levels may have different effects on bone than do chronically sustained decreases. To test this hypothesis, we compared two NPS R-568 dosing regimens in rats with chronic renal insufficiency induced by two intravenous injections of adriamycin. Fourteen weeks after the second adriamycin injection, creatinine clearance was reduced by 52%, PTH levels were elevated approximately 2.5-fold, and serum 25(OH)D3 and 1,25(OH)2D3 levels were reduced substantially. Treatment by daily per os gavage, which decreased PTH levels intermittently, or continuous subcutaneous infusion, which resulted in a sustained suppression of serum PTH levels, then began for 8 weeks. Despite the hyperparathyroidism, the adriamycin-injected rats developed a low-turnover bone lesion with osteomalacia (fourfold increase in osteoid volume in the proximal tibial metaphysis) and osteopenia (67% decrease in cancellous bone volume and an 18% reduction in bone mineral density at the distal femur). Daily administered (but not infused) NPS R-568 significantly increased cancellous bone volume solely by normalizing trabecular thickness, and increased femoral bone mineral density by 14%. These results indicate that daily intermittent, but not sustained, decreases in PTH levels have an "anabolic-like" effect on bones with a low-turnover lesion in this animal model of chronic renal insufficiency.

Aniline Compounds↗
PubMed2000

Periodate oxidation of crystalline cellulose.

Conversion of 1,2-dihydroxyl groups to dialdehyde by periodate oxidation is a useful method of derivatizing polysaccharides but has not been extensively utilized in derivatization of cellulose because of complicacy due to the crystalline nature of cellulose. To understand the influence of cellulose crystallinity on this reaction, we investigated how the periodate oxidation proceeds with a highly crystalline cellulose of the marine alga Cladophora sp. The crystallinity of the oxidized cellulose, determined by X-ray diffraction, decreased according to the oxidation level. The half-height widths of equatorial diffraction peaks were nearly unchanged. The solid-state 13C NMR spectra did not show peaks corresponding to aldehyde groups, but solution 13C NMR spectra showed the presence of dicarboxylic groups after subsequent oxidation by sodium chlorite. Transmission electron microscopy showed that microfibrils of Cladophora tended to be bent and more flexible than the original sample. Gold labeling of the aldehyde groups, mediated by thiosemicarbazide derivatization, revealed a highly uneven distribution of dialdehyde groups. When treated by 50% (w/v) sulfuric acid, partially oxidized Cladophora cellulose gave many short fragments of microfibril. These features indicate that the periodate oxidation proceeds by forming dialdehyde groups in longitudinally spaced, bandlike domains.

Aldehydes↗
PubMed2000

Nonenzymatic template-directed condensation of short-chained oligouridylates on a poly(A) template.

An oligouridylate with chain-length of more than three was condensed on a polyadenylate [poly(A)] template with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDAC) in imidazole buffer. The condensation reaction proceeds via the phosphorimidazolide of the oligouridylate as an intermediate. Pentauridylate [(pU)5] was converted to decauridylate [(pU)10] in 10% yield at 0 degree C for 7 days in the presence of the poly(A) template, while no coupling product was obtained in the absence of the poly(A) template. The resulting linkage of the (pU)10 was mainly 2'-5' linkage.

Base Sequence↗
PubMed2000

Retinol equivalence of carotenoids can be evaluated by hepatic vitamin A content.

The present study demonstrates a new method to evaluate the bioavailability of carotenoids based on the calculation of the hepatic retinol contents. Weaning male rats of Wistar strain were divided into 5 groups. Each group respectively received retinol acetate (2000-10,000 IU per kg diet), alpha-carotene (2400-6000 micrograms per kg diet), beta-carotene (2400-6000 micrograms per kg diet), mixture of alpha- and beta-carotenes in the ratio of 1:2 (2400 and 4800 micrograms per kg dit), and palm-carotene oil (2400-6000 micrograms per kg diet). The derived retinol equivalences of each carotenoid calculated according to the hepatic retinol contents were almost constant regardless of the volume of respective intake (alpha-carotene: 1.25 micrograms per IU; beta-carotene: 0.59 microgram per IU; mixture of alpha- and beta-carotene in the ratio of 1:2: 0.96 microgram per IU; Palm-carotene oil: 1.23 micrograms per IU). The results suggest that the hepatic retinol contents can be used as a new measure to evaluate the vitamin A bioavailability of carotenoids.

Animals↗
PubMed2000

Changes in CD4+CD8-/CD4-CD8+ ratio and humoral immune functions in vitamin B12-deficient rats.

To clarify the role of vitamin B12 in the function of cell-mediated and humoral immune functions, the splenocytes expression of CD4, CD8 and serum C3, IgM, IgG concentrations were examined in vitamin B12-deficient rats, and the effect of the administration of methylcobalamin was also studied. The CD4+CD8-/CD4-CD8+ ratio in splenocytes was significantly higher in vitamin B12-deficient rats than in control rats (p < 0.05). The value in the 48 hours after methylcobalamin administration group, was within the normal range (p < 0.05). From these results, the elevation of the CD4+CD8-/CD4-CD8+ ratio by vitamin B12-deficiency was confirmed in rats. The serum C3, IgM and IgG concentrations were lower in the vitamin B12-deficient group than in the control group. These findings suggest that vitamin B12 plays a role in maintaining the immune function in rats.

Animals↗
PubMed2000

Occult vascular malformations of the spinal cord: report of four cases not detected by angiography.

Angiographically occult vascular malformations (AOVMs) are reported. Although cavernous malformations, the most common type among the spinal intramedullary AOVMs, have been well documented, the natural history and clinical features of non-cavernous type AOVMs of the spinal cord remain obscure. We have evaluated four cases of non-cavernous AOVMs in the past 9 years. Although the clinical features and magnetic-resonance imaging (MRI) of three cases were similar to those previously reported, the other one had unusual features of insidious onset with limb asymmetry. The natural history of intramedullary occult AVMs remains enigmatic. One speculation for the neurological deterioration is that it results from repeated hemorrhages around the vessels or from intralumenal thrombosis.

Adult↗