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T Fujiwara

Publications and source records attributed to T Fujiwara.

At least 145 records · Page 8Linked to original sources
PubMed2000

Prevention of halothane-induced hepatotoxicity by hemin pretreatment: protective role of heme oxygenase-1 induction.

Reductive metabolism of halothane in phenobarbital-pretreated rats is known to increase free radical formation that results in hepatotoxicity. It also is associated with a marked induction of microsomal heme oxygenase-1 (HO-1), suggesting that there is an alteration in heme metabolism. In this study, we examined heme metabolism in rats pretreated with phenobarbital, followed by exposure to halothane-hypoxia. In this model, there was a significant decrease in microsomal cytochrome P450 content in the liver, followed by a rapid increase in free heme concentration and a decrease in the level of mRNA for the nonspecific delta-aminolevulinate synthase. A transient but dramatic induction of HO-1 mRNA and a prolonged induction of heat shock protein 70 mRNA also occurred. The HO-1 protein was detected principally in the hepatocytes around the central vein. Serum alanine transaminase (ALT) activity, an indicator of hepatic dysfunction, increased continuously throughout the experiment. Hemin pretreatment induced hepatic HO-1 with abrogation of the halothane-induced hepatotoxicity in this model, as judged by ALT activity and normal histology. Our findings in this study thus indicate that halothane-induced hepatotoxicity is due not only to its reductive metabolite formation, but also to an increase in hepatic free heme concentration, which is a potent prooxidant; HO-1 induction is an important protective response against such changes. This is also the first study to demonstrate that hemin pretreatment, which induces HO-1 prior to exposure to halothane, effectively prevents halothane-induced hepatotoxicity.

5-Aminolevulinate Synthetase↗
PubMed2000

Solvent extraction coupled on-line to a reversed micellar mediated chemiluminescence detection system for trace-level determination of atropine.

A fast and sensitive method for the determination of atropine, an alkaloid closely related to cocaine, is proposed. The principles of on-line ion-pair formation of alkaloid-metal complexes and liquid-liquid extraction are applied to the chemiluminescence determination of atropine. On mixing with a reversed micellar medium of cetyltrimethylammonium chloride in dichloromethane-cyclohexane (1:1 v/v)-water (0.3 M Na2CO3) containing luminol, the ion-pair complex of tetrachloroaurate(III) with atropinium produced an analytical chemiluminescence signal when it entered the reversed micellar water pool. Using the reverse-flow injection and chemical conditions optimized for atropine in aqueous samples, a detection limit of 1 ng/mL was achieved and a linear calibration graph was obtained with a wide dynamic range from 10 ng/mL to 100 micrograms/mL. The proposed method is simple and provides a good precision with a relative standard deviation (n = 6) of ca. 3% at the atropine concentration of 100 ng/mL. After a preliminary study involving the potential interference from species of organic, inorganic, and metallic nature, the method was applied to the determination of atropine in artificial urine samples and of atropine and scopolamine in pharmaceutical formulations.

Atropine↗
PubMed2000

Purification and characterization of dissimilatory nitrate reductase from a denitrifying halophilic archaeon, Haloarcula marismortui.

Dissimilatory nitrate reductase was purified from a denitrifying halophilic archaeon, Haloarcula marismortui, to an electrophoretically homogeneous state. The purified enzyme was inferred to be a homotetramer composed of a 63 kDa polypeptide. The electron paramagnetic resonance spectrum of the purified enzyme revealed typical rhombic signals which were ascribed to Mo(V) in the Mo-molybdopterin complex. Like the bacterial membrane-bound (Nar-) enzyme, the purified enzyme supported the catalysis of chlorate. The enzyme was activated in extreme saline conditions and the values of k(cat) and K(m) toward nitrate were 145 s(-1) and 79 microM, respectively, in the presence of 2.0 M NaCl.

Bacteria↗
PubMed2000

Identification of human MutY homolog (hMYH) as a repair enzyme for 2-hydroxyadenine in DNA and detection of multiple forms of hMYH located in nuclei and mitochondria.

An enzyme activity introducing an alkali-labile site at 2-hydroxyadenine (2-OH-A) in double-stranded oligonucleotides was detected in nuclear extracts of Jurkat cells. This activity co-eluted with activities toward adenine paired with guanine and 8-oxo-7,8-dihydroguanine (8-oxoG) as a single peak corresponding to a 55 kDa molecular mass on gel filtration chromatography. Further co-purification was then done. Western blotting revealed that these activities also co-purified with a 52 kDa polypeptide which reacted with antibodies against human MYH (anti-hMYH). Recombinant hMYH has essentially similar activities to the partially purified enzyme. Thus, hMYH is likely to possess both adenine and 2-OH-A DNA glycosylase activities. In nuclear extracts from Jurkat cells, a 52 kDa polypeptide was detected with a small amount of 53 kDa polypeptide, while in mitochondrial extracts a 57 kDa polypeptide was detected using anti-hMYH. With amplification of the 5'-regions of the hMYH cDNA, 10 forms of hMYH transcripts were identified and subgrouped into three types, each with a unique 5' sequence. These hMYH transcripts are likely to encode multiple authentic hMYH polypeptides including the 52, 53 and 57 kDa polypeptides detected in Jurkat cells.

Adenine↗
PubMed2000

Prevention of acute liver failure in rats with reversibly immortalized human hepatocytes.

Because of a critical shortage in suitable organs, many patients with terminal liver disease die each year before liver transplantation can be performed. Transplantation of isolated hepatocytes has been proposed for the temporary metabolic support of patients awaiting liver transplantation or spontaneous reversion of their liver disease. A major limitation of this form of therapy is the present inability to isolate an adequate number of transplantable hepatocytes. A highly differentiated cell line, NKNT-3, was generated by retroviral transfer in normal primary adult human hepatocytes of an immortalizing gene that can be subsequently and completely excised by Cre/Lox site-specific recombination. When transplanted into the spleen of rats under transient immunosuppression, reversibly immortalized NKNT-3 cells provided life-saving metabolic support during acute liver failure induced by 90% hepatectomy.

Adult↗
PubMed2000

Overexpression of the wild-type p53 gene inhibits NF-kappaB activity and synergizes with aspirin to induce apoptosis in human colon cancer cells.

The tumor suppressor gene p53 is a potent transcriptional regulator of genes which are involved in many cellular activities including cell cycle arrest, apoptosis, and angiogenesis. Recent studies have demonstrated that the activation of the transcriptional factor nuclear factor kappaB (NF-kappaB) plays an essential role in preventing apoptotic cell death. In this study, to better understand the mechanism responsible for the p53-mediated apoptosis, the effect of wild-type p53 (wt-p53) gene transfer on nuclear expression of NF-kappaB was determined in human colon cancer cell lines. A Western blot analysis of nuclear extracts demonstrated that NF-kappaB protein levels in the nuclei were suppressed by the transient expression of the wt-p53 in a dose-dependent manner. Transduced wt-p53 expression increased the cytoplasmic expression of I kappaB alpha as well as its binding ability to NF-kappaB, thus markedly reducing the amount of NF-kappaB that translocated to the nucleus. The decrease in nuclear NF-kappaB protein correlated with the decreased NF-kappaB constitutive activity measured by electrophoretic mobility shift assay. Furthermore, parental cells transfected with NF-kappaB were better protected from cell death induced by the wt-p53 gene transfer. We also found that the wt-p53 gene transfer was synergistic with aspirin (acetylsalicylic acid) in inhibiting NF-kappaB constitutive activity, resulting in enhanced apoptotic cell death. These results suggest that the inhibition of NF-kappaB activity is a plausible mechanism for apoptosis induced by the wt-p53 gene transfer in human colon cancer cells and that anti-NF-kappaB reagent aspirin could make these cells more susceptible to apoptosis.

Adenocarcinoma↗
PubMed2000

Both fertilization promoting peptide and adenosine stimulate capacitation but inhibit spontaneous acrosome loss in ejaculated boar spermatozoa in vitro.

Both fertilization promoting peptide (FPP) and adenosine stimulate capacitation and inhibit spontaneous acrosome loss in epididymal mouse spermatozoa; these responses involve modulation of the adenylyl cyclase (AC)/cAMP signal transduction pathway. However, it was unclear whether these responses were restricted to the mouse or possibly common to many mammalian species. To address this question, the response of boar spermatozoa to FPP and/or adenosine was evaluated. FPP is found in nanomolar concentrations in seminal plasma of several mammals, but not the pig. When cultured in caffeine-containing Medium 199 for 2 hr, chlortetracycline fluorescence evaluation indicated that neither FPP nor adenosine stimulated boar sperm capacitation per se but did inhibit spontaneous acrosome loss. However, in caffeine-free medium, FPP and adenosine both stimulated capacitation and inhibited spontaneous acrosome loss, suggesting that boar spermatozoa have receptors for both FPP and adenosine. Gln-FPP, a competitive inhibitor of FPP in mouse spermatozoa, has recently been shown to inhibit mouse sperm responses to adenosine as well, suggesting that FPP receptors and adenosine receptors interact in some way. Used with boar spermatozoa, Gln-FPP also significantly inhibited responses to both FPP and adenosine. These responses suggest that mechanisms whereby FPP and adenosine can regulate sperm function, via AC/cAMP, are of considerable physiological significance. Mouse, human, and now boar spermatozoa have been shown to respond to FPP, suggesting that these mechanisms may be common to many mammalian species. We also suggest that the effects of FPP and adenosine could also be exploited to maximize monospermic fertilization in porcine in vitro fertilization.

Acrosome↗
PubMed2000

Compound radiofrequency-driven recoupling pulse sequences for efficient magnetization transfer by homonuclear dipolar interaction under magic-angle spinning conditions

The maximum of the transferred magnetization in rotating powdered solids under the radiofrequency-driven recoupling (RFDR) pulse sequence is enhanced by reducing the orientation dependence of the effective recoupled homonuclear dipolar interaction. The compound RFDR (CRFDR) pulse sequence for this enhancement consists of RFDR pulse units (tau(i)-pi-tau(R)-pi-1171;tau(i)) with different tau(i), where tau(R) is the sample rotation period, tau(i) and 1171;tau(i) (=tau(R) - tau(i)) are delays, and pi is a 180 degrees pulse. The delay tau(i) modifies the zero-quantum spin operators and the sample rotation-angle dependence of the recoupled dipolar Hamiltonian. The CRFDR pulse sequences were optimized for mixing by varying tau(i). Numerical simulation for the two-spin system only with a dipolar interaction and isotropic chemical shifts indicates that the transfer efficiency of CRFDR averaged over the powder is about 70%, which is 30% higher than the efficiency of the RFDR pulse over a broad range of about 1/tau(R) in resonance frequency difference. The CRFDR sequences need about 60% longer mixing times to maximize the transferred magnetizaion in comparison with the original RFDR sequence. Chemical shift anisotropy, the other dipolar interactions, and relaxation generally reduce the enhancement by CRFDR. Experiments for fully (13)C-labeled alanine, however, show that the maximum of the magnetization transferred with CRFDR from the carboxyl to alpha carbon is about 15% greater than that with RFDR. Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Troglitazone and emerging glitazones: new avenues for potential therapeutic benefits beyond glycemic control.

Insulin resistance is characterized as one of the major pathogeneses of type 2 diabetes and has been associated with these same cardiovascular risk factors. Troglitazone, rosiglitazone, and pioglitazone are a new class of oral antidiabetic agents which can ameliorate peripheral insulin resistance in type 2 diabetes. There is considerable evidence that trogliterazone may have beneficial effects on cardiovascular and metabolic abnormalities associated with insulin resistance. There is supportive evidence for positive effects of the other glitazones, but they have been less well studied. These potential benefits span effects ranging from molecular events in the arterial wall to amelioration and/or improvement in lipid parameters known to be associated with atherosclerosis.

Animals↗
PubMed2000

Human papillomavirus type 33 DNA in breast cancer in Chinese.

BACKGROUND: The association between human papillomavirus (HPV) and anogenital tumors, especially cervical cancer, is well documented. However, it remains unclear whether there is also a correlation between HPV infection and human breast cancer. METHODS: We used PCR and Southern blot hybridization to analyze HPV-related DNA specimens from 32 cases of invasive ductal carcinoma operated upon in the Shanghai region of China. RESULTS: DNA derived from HPV33 was detected in 14 cases (43.8%). No HPV16 or HPV18 DNA was detected in any of the cases in this study. This is the first report demonstrating a correlation between HPV33 infection and breast cancer. CONCLUSIONS: Our results suggest that HPV33 infection may be involved in the pathogenesis of breast cancer in Chinese.

Adult↗
PubMed2000

Adenovirus-mediated viral IL-10 gene transfer prolongs survival of xenogeneic spheroidal aggregate-cultured hepatocytes.

Xenotransplantation of hepatocytes appears to be a novel promising therapy for some forms of liver disease, and may well overcome the problem of donor shortage. We have previously reported that hepatocytes with a spheroidal shape (spheroids) are ideal for cell transplantation. The application of gene transfer techniques to this hepatocyte transplantation could possibly regulate the xenogeneic rejection reaction and, therefore, result in prolongation of the survival of the transplanted hepatocytes. In this study, we chose the adenovirus as a vector and an immunosuppressive cytokine named viral IL-10 (vIL-10) for transfection. A series of experiments was performed to elucidate the efficacy of transfection to the spheroids with adenovirus vectors and the effect of transfected vIL-10 on the survival of xenogeneic hepatocytes. We examined the cell survival quantitatively by evaluating beta-galactosidase (beta-gal) activity, which was transfected into the hepatocytes in the xenogeneic spleen, and semiquantitatively by the histological findings. The results of in-vitro studies identified an efficient expression of the beta-gal gene within the spheroids infected with Ad-CMVLacZ (LacZ-encoding adenovirus vector with CMV promotor) and the presence of BCRF1 mRNA within the spheroids transfected with AdCMVvIL-10 (vIL-10-expressing adenovirus vector with CMV promotor) under the condition of 1 MOI, for 1 h. Xenogeneic hepatocytes with a spheroidal shape showed comparable survival to syngeneic hepatocytes for up to 4 days after transplantation with co-transplantation of the vIL-10-transfected hepatocytes. From this study, we concluded that adenovirus-mediated vIL-10 gene transfer prolongs the survival of xenogeneic hepatocyte spheroids. Furthermore, spheroids possess ideal properties for gene transfection, as well as cell transplantation.

Adenoviridae↗
PubMed2000

N-methyl-1-deoxynojirimycin (MOR-14), an alpha-glucosidase inhibitor, markedly improves postischemic left ventricular dysfunction.

We examined whether pharmacological inhibition of glycogenolysis by N-methyl-1-deoxynojirimycin (MOR-14), a new compound which reduces the glycogenolytic rate by inhibiting the alpha-1,6-glucosidase activity of the glycogen-debranching enzyme, can protect the heart against postischemic left ventricular dysfunction. The hearts of male Sprague-Dawley rats were excised, and perfused on a Langendorff apparatus with Krebs-Henseleit solution with a gas mixture of 95% O2 and 5% CO2. The hearts were paced at 320 beats/min except during the ischemia. Left ventricular developed pressure (LVDP, mmHg), +/-dP/dt (mmHg/s), and coronary flow (ml/min) were continuously monitored. All hearts were perfused for a total of 120 min including a 30-min preischemic period followed by a 30-min episode of global ischemia and 60 min reperfusion. with or without 0.5 or 2 mM of MOR-14 during the 30-min preischemic period or the first 30 min of reperfusion. In another series of experiments, the myocardial content of glycogen and lactate was measured during the 30-min episode of ischemia in groups treated with and without 2mM of MOR-14. Preischemic but not postischemic treatment with MOR-14 significantly improved LVDP and +/-dP/dt without altering coronary flow during reperfusion in a dose-dependent manner. MOR-14 significantly preserved the glycogen content and significantly attenuated the lactate accumulation during the 30-min episode of ischemia. Preischemic treatment with MOR-14 is protective against postischemic left ventricular dysfunction through the inhibition of glycogenolysis in the isolated rat heart.

1-Deoxynojirimycin↗
PubMed2000

Gallic acid induces vascular smooth muscle cell death via hydroxyl radical production.

In the present study, we investigated whether gallic acid (GA) can induce death in cultured vascular smooth muscle cells (VSMCs), and whether production of the hydroxyl radical (.OH) is involved in the process of GA action. GA killed cultured VSMCs from rat aorta, in a dosc- and time-dependent manner. Cytoplasmic shrinkage and nuclear condensation were observed light microscopically in GA-treated VSMCs, which appeared apoptotic. However, the ultrastructure of the VSMC was not typical of apoptosis: nuclear condensation was not glossy, and the plasma membrane and subccellular organelles were disrupted. Although the VSMC were positive for in situ nick end-labeling (TUNEL). they did not show a DNA ladder pattern on gel electrophoresis and were negative for T aq polymerase-based in situ ligation, which is more specific for apoptosis than TUNEL. Moreover. GA-induced cell death was not prevented by Boc-Asp-fmk (a pan-caspase inhibitor). Production of OH was detected in GA-treated VSMCs using high-performance liquid chromatography with salicylic acid as a trapping agent. Lipid peroxidation was also observed. The production of .OH was inhibited by catalase (CAT) and deferoxamine (DFX), and these treatments completely rescued VSMCs from cell death. In a cell-free system, GA produced .OH in the presence of Fe2+-EDTA, which was quenched by CAT and DFX, suggesting involvement of the Haber-Weiss reaction. Oxidative stress by reactive oxygen species, .OH in particular, is one of the mechanisms of GA-induced death of VSMCs, the mode of which was different from typical apoptosis.

Animals↗
PubMed2000

Heterotopic gastric mucosa in the gallbladder.

We report on a case of heterotopic gastric mucosa in the body of the gallbladder. A 39-year-old man, who was asymptomatic, visited our hospital because of a polypoid lesion in the gallbladder, discovered during a routine health screening. Ultrasonography (US) revealed a broad-based polypoid lesion 1.7 cm in diameter in the body of the gallbladder, which was free of gallstones. The gallbladder mass was faintly enhanced by helical computed tomography. Laparoscopic cholecystectomy was performed because of the possibility of malignancy. The specimen revealed a 1.7 x 1.3 cm polypoid lesion with deep delle in the body, with no gallstones in the gallbladder. Intraoperative frozen examination yielded a diagnosis of hyperplastic polyp of the gallbladder. Histologically, the polypoid lesion consisted of gastric fundic glands located in the whole wall of the gallbladder. The surrounding mucosa consisted of almost normal epithelium without any metaplastic changes. Postoperative technetium 99m-pertechnetate scintigraphy demonstrated no evidence of gastric heterotopia elsewhere in the body. We also review 18 other reports of heterotopic gastric mucosa in the gallbladder in the Japanese medical literature.

Adult↗
PubMed2000

Internal hernia with triple hiatus of congenital origin: report of a case.

We report herein the case of a 65-year-old woman who was referred to our department with prolonged ileus symptoms despite conservative therapy. A plain abdominal radiograph showed intestinal gas shadows with an air-fluid level in the lesser curvature of the stomach. As no improvement was achieved by the insertion of a short tube, a long tube was inserted. A loop formation of the long tube in the subphrenic region was detected on an abdominal radiograph, and an enterogram showed an interruption in the ileum in the lower abdomen. The patient was diagnosed as having an adhesional ileus and a strangulated ileus due to a lesser sac hernia. A laparotomy was performed which revealed that the small intestine had herniated into the lesser sac space through a hiatus of Treitz' fossa and a hiatus in the transverse mesocolon. Furthermore, part of the small intestine had herniated through an omental hiatus. The herniated intestine was manually reduced and the hiatus was closed. However, as the right ovary was found to have adhered to the ileum and stenosis was seen, we were forced to perform partial resection of the ileum. Considering that this patient had no history of laparotomy in the upper abdomen, abdominal injury, or acute abdomen, it was surmised that the three abnormal hiatuses were congenital.

Aged↗
PubMed2000

Isolation and characterization of simian immunodeficiency virus variants that are resistant to nonnucleoside reverse transcriptase inhibitors.

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) act quite specifically on human immunodeficiency virus type 1 (HIV-1). In general, they are not effective on human immunodeficiency virus type 2 (HIV-2) or simian immunodeficiency virus (SIV). Only SIV strains from African green monkeys are sensitive to several NNRTIs. Here we isolated NNRTI- and 3TC-resistant SIVagm variants. Viruses resistant to delavirdine contained V112I and M231I substitutions, while those resistant to 3TC contained a M 185I substitution. These amino acids are highly conserved in HIV-1, HIV-2, SIVmac and SIVagm, and the M184I (M185I in SIVagm) substitution was observed in 3TC-resistant HIV-1 and SIVmac. The roles of the observed mutations in NNRTI-resistance of SIVagm and HIV-1 were further confirmed by site-directed mutagenesis. The present results have provided a new insight into the common mechanism of sensitivity of HIV- 1 and SIVagm to NNRTIs.

Amino Acid Sequence↗
PubMed2000

Analysis of follicular fluid hormone concentrations and granulosa cell mRNA levels for the inhibin-activin-follistatin system: relation to oocyte and embryo characteristics.

OBJECTIVE: To explore the potential roles of inhibin, activin, and follistatin in human oocyte development by quantifying their intrafollicular biosynthesis. DESIGN: Prospective, nonrandomized study. SETTING: An IVF unit and academic research laboratory. PATIENT(S): Thirty one patients undergoing IVF. INTERVENTION(S): Human menopausal gonadotropins or human FSH (or both) were administered. Single-follicle aspirates (n = 110) were collected for analysis. MAIN OUTCOME MEASURE(S): Concentrations of dimeric, total and pro-alphaC inhibin forms; activin A; follistatin; estradiol; and progesterone were measured in follicular fluids. Granulosa-cell mRNA was analyzed for alpha, beta A, and beta B inhibin and activin subunits; follistatin; activin receptors; and beta-actin. Hormone concentrations and mRNA levels were correlated with oocytes or embryos from the same follicles. RESULT(S): Levels of progesterone and follistatin were significantly greater in follicles containing MI or MII oocytes than in those containing GV oocytes. Inhibin alpha-subunit mRNA levels were significantly higher in follicles containing maturing oocytes, the highest-quality oocytes, and oocytes that were subsequently fertilized. In contrast, inhibin alpha-subunit mRNA levels were significantly lower in follicles from which higher-quality embryos were obtained. CONCLUSION(S): Inhibin alpha-subunit biosynthesis is associated with normal oocyte and follicle maturation, but excessive alpha-inhibin is associated with poor embryo quality. None of the hormones analyzed were associated with oocyte or embryo quality.

Actins↗