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J Watanabe

Publications and source records attributed to J Watanabe.

At least 127 records · Page 7Linked to original sources
PubMed1999

[Unrelated bone marrow transplantation in two severe aplastic anemia patients preconditioned with a regimen of cyclophosphamide, antithymocyte globulin, and total body irradiation].

We report our experiences with HLA-matched unrelated bonemarrow transplantation combining a preconditioning regimen of cyclophosphamide, antithymocyte globulin (ATG), and total body irradiation for two patients with severe aplastic anemia (SAA) who had already undergone repeated blood transfusions. Short-term methotrexate and cyclosporine were administered for graft-versus-host disease (GVHD) prophylaxis. Both patients achieved rapid engraftment within 3 weeks, furthermore, neither acute nor chronic GVHD developed. Our conditioning regimen appeared to be well-suited for unrelated bone marrow transplantation in heavily transfused SAA patients. However, both patients experienced bouts of fever about 20-30 and 40-50 days after transplantation, and it was difficult to differentiate whether they were affected by acute GVHD, cytomegalovirus (CMV) infections, or serum sickness. Because weakly positive CMV antigenemia was detected, both patients were given ganciclovir. Although their fever did not respond initially, it gradually subsided following the combined administration of prednisolone. These outcomes suggest it is essential that attention be devoted to the potential for serum sickness and the high risk of herpes virus infections, particularly by CMV, following the use of intensive preconditioning regimens that include ATG.

Adolescent↗
PubMed1999

[Transitional cell carcinoma in the ureter showing inverted proliferation: a case report].

A case of transitional cell carcinoma in the ureter showing inverted proliferation is reported. A tumor in the middle third of the right ureter was found in a 67-year-old male complaining of gross hematuria. Since positive findings of malignancy were obtained in a washing examination of urine cytology, right nephroureterectomy was performed. The gross specimen consisted of a polypoid and pedunculated 22 x 8 mm tumor which showed a smooth surface as in normal ureteral mucosa. Histopathologically, the tumor was lined with normal transitional epithelium but filled with transitional cell carcinoma, grade 1. Diagnosis and treatment of ureteral tumors showing inverted proliferation are discussed.

Aged↗
PubMed1998

Changes in the gap junctional intercellular communication in renal tubular epithelial cells in vitro treated with renal carcinogens.

Gap junctional intercellular communications (GJIC) are known as the channels for the direct transfer of cytoplasmic molecules between neighboring cells and are lost during transformation of normal cells. To study the function and the molecular mechanism for the loss of GJIC, the effects of dimethylnitrosamine, KBrO3 and FeSO4 x 7H2O, which are known as chemical tumor promoters of the kidney on the GJIC function and the expression of connexin 43 of Madin-Darby canine kidney (MDCK) epithelial cells, were examined. These tumor promoters inhibited the GJIC in MDCK cells. The expression of connexin 43 mRNA and connexin 43 protein was not altered by these treatments, whereas immunocytochemical study revealed that the distribution of connexin 43 protein was changed from the cell surface to the cytoplasma. These data suggest that blockage of GJIC in MDCK cells treated with renal carcinogens support the hypothesis that loss of GJIC might be important in renal carcinogenesis.

Animals↗
PubMed1998

Physiological mechanism-based analysis of dose-dependent gastrointestinal absorption of L-carnitine in rats.

We evaluated the dose-dependent (saturable) gastrointestinal absorption of L-carnitine, a lipid-lowering agent, in rats by a physiological mechanism-based approach to clarify its absorption characteristics and to examine the in vitro (in situ)-in vivo correlation in intestinal transport. The intestinal absorption rate constant (ka), which was estimated by the analysis of gastrointestinal disposition, decreased markedly from 0.1061 to 0.0042 min(-1) when the dose was increased from 0.05 micromol rat(-1) (low dose) to 100 micromol rat(-1) (high dose). The dose-dependence in ka was attributable to the saturability of intestinal transport that, in the perfused intestine, was similar to the saturability in ka. At the high dose, the apparent absorption rate constant (k'a) of 0.0021 min(-1), which was estimated by the analysis of plasma concentrations after oral administration, was an order of magnitude smaller than the gastric emptying rate constant (kg) of 0.059 min(-1) and comparable with the ka of 0.0042 min(-1), suggesting that the gastrointestinal absorption of L-carnitine is absorption-limited in the intestine. At the low dose, where intestinal L-carnitine absorption was far more efficient, the k'a of 0.0172 min(-1) was smaller than the ka of 0.1061 min(-1) and closer to the kg of 0.072 min(-1), suggesting that apparent absorption was retarded by gastric emptying which is less efficient than intestinal absorption. This shift in the rate-determining process with an increase in dose explains the less marked dose dependence in k'a compared with ka. The bioavailability decreased from 100 to 42% with an increase in dose. This could be accounted for quantitatively by a reduction in the fraction absorbed (F(a,oral)) due to a reduction in ka, assuming first-order absorption during the transit time of T(si) through the small intestine (F(a,oral) = 1 - exp(-ka x T(si))). Thus, using L-carnitine as a model, this study has successfully demonstrated that the saturability in gastrointestinal absorption can be correlated with the intestinal transport in a quantitative and mechanism-based manner. This should be of help not only for developing more efficient oral L-carnitine delivery strategies, taking advantage of in vitro (in situ) information about the intestinal transport mechanism, but also for establishing a more generally applicable in vitro (in situ)-in vivo correlation in gastrointestinal absorption.

Algorithms↗
PubMed1998

Regulation of intracellular free Mg2+ concentration in isolated rat hearts via beta-adrenergic and muscarinic receptors.

Regulation of the intracellular free magnesium concentration ([Mg2+]i) was investigated in isolated rat hearts, using 31P-nuclear magnetic resonance (31P-NMR). [Mg2+]i was found to be slowly and significantly decreased during prolonged application of isoproterenol (ISO) through beta-adrenergic receptor stimulation, and restored by subsequent washouts. The ISO-induced decrease in [Mg2+]i was antagonized by addition of a muscarinic receptor agonist, carbachol (CCh). In the presence of atropine, CCh did not exert this effect. A water-soluble forskolin derivative, NKH477, which directly activates adenylate cyclase, also caused a decrease in [Mg2+]i, which could be antagonized by CCh, but a greater concentration was required as compared to the ISO case. The manner of [Mg2+]i regulation mimicked those noted for the action potential duration and the Ca2+ channel current, in which cAMP is known to act as a second messenger. Even in the presence of a Ca2+ channel blocker, verapamil, [Mg2+]i was reversibly decreased by ISO. Changes in the intracellular ATP concentration demonstrated any clear correlation with changes in [Mg2+]i. These results suggest that [Mg2+]i can be controlled by a balance of sympathetic and parasympathetic activities. cAMP may play a key role in the [Mg2+]i regulation via beta-adrenergic and muscarinic receptors, although some other metabolic pathways also appear to be involved. Hormonally induced changes in [Mg2+]i have possible clinical significance.

Animals↗
PubMed1998

Culture of stromal cells derived from medullary cavity of human long bone in the presence of 1,25-dihydroxyvitamin D3, recombinant human bone morphogenetic protein-2, or ipriflavone.

We previously showed that stromal cells derived from bone marrow specimens formed at the fracture site of human long bone differentiated during culture to polygonal cells and spindle cells, and polygonal cells, but not spindle cells, produced calcified matrix. To clarify the origin of polygonal and/or spindle cells, and factors necessary for differentiation of marrow stromal cells to osteogenic cells, we cultured stromal cells derived from the normal (unfractured) medullary cavity (SCN) as well as stromal cells from the medullary cavity distant from the fracture site (SCF). After 3 weeks of primary culture and 2 days of secondary culture, the cells were cultured in medium containing 1,25-dihydroxyvitamin D3 (VD), recombinant human bone morphogenetic protein-2 (BMP), or ipriflavone (IF) for 3 weeks. For biochemical analysis, cells reaching confluence after 3 weeks of secondary culture were cultured with one of the factors for 3 days. Some of SCF cultured with VD or IF were transformed to polygonal cells, and showed high alkaline phosphatase (ALPase) activity and high osteocalcin and insoluble calcium production. Cloned polygonal cells from the SCF formed nodules and aggregates consisting of calcium. Other SCF cultured with VD or IF and SCF cultured with BMP were spindle shaped. Some spindle-shaped cells from SCF cultured with BMP or IF revealed high ALPase activity and high osteocalcin production, comparable with the spindle cells from the fracture site. However, spindle-shaped cells from SCF cultured with VD and other spindle-shaped cells from SCF cultured with BMP or IF showed low ALPase activity and low osteocalcin production. The results show that SCF probably contain at least three subpopulations: (a) cells that differentiate to polygonal cells by the influence of VD or IF; (b) cells that differentiate to the spindle cells by the influence of BMP or IF; and (c) cells that are not transformed by the influence of VD, BMP, or IF.

Adolescent↗
PubMed1998

CMV retinitis after cessation of ganciclovir therapy for CMV antigenemia in an unrelated BMT recipient.

An 11-year-old boy with severe aplastic anemia underwent unrelated BMT following TBI, antithymocyte globulin and CY. On day +23, CMV antigenemia was detected which resolved with ganciclovir. Eight days after discontinuing ganciclovir, he complained of impaired visual acuity. Ophthalmologic findings and a positive PCR study using anterior chamber fluid from the right eye confirmed the presumptive diagnosis of CMV retinitis, although CMV antigenemia and PCR studies using PBMC were then negative. He was successfully re-treated with ganciclovir. CMV retinitis should be considered even when CMV antigenemia is not present or PCR using PBMC is negative.

Anemia, Aplastic↗
PubMed1998

Peripheral primitive neuroectodermal tumour of the lung: report of two cases.

AIMS: We report two unusual cases of intrapulmonary small round cell tumour with evidence that they are primitive neuroectodermal tumours. METHODS AND RESULTS: The patients were a 25-year-old woman and a 15-year-old man, in whom mass shadows were found by routine chest radiography. Both tumours were located in the pulmonary parenchyma, and there was no evidence of an extrapulmonary involvement by the tumour. The lesions showed morphological and immunophenotypic features consistent with peripheral primitive neuroectodermal tumour (pPNET). These features included a hypercellular diffuse growth pattern of closely packed small round cells occasionally forming abortive Homer-Wright-type rosettes and intense immuroreactivities to neurone-specific enolase and MIC2 gene product (O13). Unusual chondroid foci were present in one of the cases. This diagnosis was further supported by the cytogenetic and reverse transcriptase-polymerase chain reaction (RT-PCR) findings of the characteristic t(11;22) chromosomal translocation and EWS/FLI-1 fusion transcripts, respectively, in one of the cases. CONCLUSIONS: These morphological and cytogenetic findings substantiate pPNET as a subtype of intrapulmonary small round cell tumours.

Adolescent↗
PubMed1998

Epidermoid cyst of the spleen with CA19-9 or carcinoembryonic antigen productions: report of three cases.

True splenic cyst is a relatively rare disease, and the majority of the cases are classified as epidermoid cysts. Three cases of epidermoid cysts in the spleen or accessory spleen were studied using an immunohistochemical technique and staining for mucin. In case 1, serum carcinoembryonic antigen (CEA) and CA19-9, and in cases 2 and 3, serum CA19-9, before surgery were markedly elevated, and these levels decreased postoperatively. This strongly indicates the relationship between the increase of tumor marker levels and the presence of the epidermoid cyst. In addition, stratified squamous epithelium in the resected tissues of cases 1 and 2 was positive for anti-CEA antibody and anti-CA19-9 antibody, and that of case 3 was positive for anti-CA19-9 antibody. This strongly supports CEA or CA19-9 production in the squamous epithelium.

Adult↗
PubMed1998

First-pass metabolism of 5-fluorouracil in rats.

The first-pass metabolism of 5-fluorouracil has been investigated in rats to compare systemic bioavailability after administration by different routes, the bioavailability after intravenous bolus administration being defined as unity. Bioavailability after oral administration (F(po)) was compared with that after intraintestinal administration into the closed loop (F(loop)) in conscious rats. F(po) was very low and variable (0.28 +/- 0.30, mean +/- s.d.), in agreement with earlier studies in man, but comparable with F(loop) (0.33 +/- 0.05), suggesting insignificant loss of 5-fluorouracil by degradation in the gastrointestinal lumen or by faecal excretion. The bioavailability after intraportal vein administration (F(ipv)) was compared with F(loop) in rats anaesthetized with pentobarbital, anaesthesia being used to maintain a stable portal drug infusion that mimics the sustained input of drug into the portal blood flow after intra-intestinal administration. F(ipv) was smaller than unity (0.68 +/- 0.03), suggesting significant hepatic first-pass metabolism, but higher than F(loop) (0.31 +/- 0.10), suggesting significant first-pass metabolism in the intestinal mucosa. The intestinal bioavailability for passage through the epithelial mucosa (Fi) was estimated, from the ratio of F(loop) to F(ipv) to be 0.46. The study revealed that both the liver and intestinal mucosa are responsible for the extensive first-pass metabolism of 5-fluorouracil after oral administration. This first-pass metabolism might be similar to that in man, in which the oral bioavailability is reportedly similar to that in the rats used in this study. The findings in this study should be of help in monitoring ways of improving oral 5-fluorouracil therapy.

Administration, Oral↗
PubMed1998

Role of estrogen and estrogen-related growth factor in the mechanism of hormone dependency of endometrial carcinoma cells.

The role of estrogen and estrogen-related growth factors in the mechanism of hormone dependency of endometrial adenocarcinoma cells was investigated. The proliferation of hormone-responsive human endometrial adenocarcinoma cells (Ishikawa cells), which possess both estrogen and progesterone receptors, was optimally stimulated by 10 nM estradiol. Both transforming growth factor (TGF)-alpha and epidermal growth factor (EGF), added to the culture media, stimulated the proliferation of Ishikawa cells in a dose-dependent manner. Anti-TGF-alpha antibody completely eliminated the stimulatory effects of TGF-alpha. Anti-EGF receptor antibody inhibited the proliferation of these cells. The production of TGF-alpha into culture media was 5-40 pg/10 cells/24 h in 9 human endometrial adenocarcinoma cells. Ten nanomoles of estradiol increased the TGF-alpha production of Ishikawa cells by approximately 2.5-fold of the control level. In contrast, the production of TGF-alpha in hormone-unresponsive HEC-50 cels was not influenced by estradiol. C-erbB-2 oncoprotein expression of human endometrial adenocarcinoma cells, detected by both immunocytochemical staining and Western blot analysis, was associated with the tumor grade of the original tumor tissues. Ten nanomoles of estradiol clearly increased the c-erbB-2 oncoprotein levels at an optimal incubation period of 72 h, whereas estradiol did not affect the expression in HEC-50 cells.

Adenocarcinoma↗
PubMed1998

Localization of xenobiotic-responsive element binding protein in rat hepatocyte nuclei after methylcholanthrene administration as revealed by in situ Southwestern hybridization.

Xenobiotic-responsive element binding protein (XRE-BP), a heterodimer of aryl hydrocarbon receptor (AhR) and its nuclear translocator (Arnt), regulates the transcription of cytochrome P-450 1A1 gene (CYP1A1) through XRE in response to xenobiotic inducers. For a better understanding of the regulatory mechanism of CYP1A1 through XRE, localization of XRE-BP was examined in liver sections or isolated hepatocyte nuclei from control and 3-methylcholanthrene (MC)-treated rats by in situ Southwestern hybridization, using synthetic XRE as a probe, and was observed by confocal laser scanning microscopy and electron microscopy. Gel mobility shift assay and competitive binding assay showed specificity of the synthetic XRE probe. XRE-BP was exclusively localized in hepatocyte nuclei in liver sections from animals 3 hr after MC injection, whereas the protein was absent in hepatocyte cytoplasm in MC-treated animals and in hepatocyte nuclei and cytoplasm in control animals. In isolated hepatocyte nuclei, XRE-BP began to accumulate in the central region between 0.5 and 3 hr, showed a peak between 3 and 6 hr, decreased gradually between 6 and 72 hr, and disappeared at 72 hr after MC injection. The protein was scarce in peripheral and nucleolar regions of the nucleus. Therefore, XRE-BP is formed in the nuclei of hepatocytes after MC stimulation. In addition, XRE-BP was found in isolated hepatocyte nuclei from control animals after preincubation with cytoplasmic lysate from MC-treated animals, although the protein was absent in the nuclei before the preincubation. These findings strongly suggest that AhR translocates from hepatocyte cytoplasm to the nucleus and forms XRE-BP in the nucleus after MC stimulation.

Animals↗
PubMed1998

Effect of 3-methylcholanthrene administration on expression of cytochrome P-450 isoforms induced by phenobarbital in rat hepatocytes.

The effects of an inducer on expression of cytochrome P-450 (P-450) isoforms induced antecedently by another inducer are unknown. Thus, we examined the amount of phenobarbital (PB)-inducible P-450 isoforms (P-450 2B1/2B2) in hepatocytes from rats injected first with PB and then with 3-methylcholanthrene (MC) (PB+MC-treated animals) by quantitative immunohistochemistry. In addition, expression of P-450 2B2 mRNA was examined by in situ hybridization. In PB-treated animals, P-450 2B1/2B2 content increased in perivenular and midzonal hepatocytes. In PB+MC-treated animals, however, the PB-induced increase in 2B1/2B2 content was suppressed in perivenular hepatocytes but promoted in midzonal hepatocytes. The hybridization signal for P-450 2B2 mRNA appeared almost exclusively in perivenular hepatocytes after 24 hr of PB injection and disappeared after 48 hr of injection. In PB+MC-treated animals, however, strong hybridization signal was observed in midzonal and perivenular hepatocytes after 48 hr of PB injection. The promotion of the increase in P-450 2B1/2B2 content in midzonal hepatocytes in PB+MC-treated animals probably corresponds to the strong hybridization signal, whereas there appeared to be a divergence between the intensity of the signal and the content in perivenular hepatocytes. The results indicate that MC administration drastically influences the pattern of expression of P-450 isoforms induced by PB in perivenular and midzonal hepatocytes.

Animals↗
PubMed1998

Dose dependency in the gastrointestinal absorption of cefatrizine: correlation between in vivo and in situ.

We evaluated the dose-dependent (saturable) gastrointestinal absorption of cefatrizine, an aminocephalosporin transported by peptide carriers, in rats by a physiological mechanism-based approach to clarify its absorption characteristics and to examine the in vitro (in situ)-in vivo correlation in intestinal transport. With an increase in oral dose (mumol/5 ml/kg) from 5 (low) to 50 (high), the intestinal absorption rate constant (ka), which was estimated by analysis of gastrointestinal disposition, decreased markedly, from 0.301 to 0.056 min-1. This decrease was ascribable to the saturability of intestinal membrane transport, of which the concentration dependency in the perfused intestine was similar in extent to the dose dependency in ka. However, the apparent absorption rate constant (ka'), which was estimated by analysis of plasma concentrations after oral administration, decreased only modestly from 0.037 to 0.023 min-1. This was associated with the result that, at the low dose, ka' was far smaller than ka and comparable with k(g) (gastric emptying rate constant), suggesting gastric emptying-limited absorption. At the high dose, where intestinal cefatrizine absorption was less efficient, ka' was closer to ka than k(g). It was also observed that the bioavailability was close to unity, independent of dose, suggesting that the intestinal transit time is long enough to achieve complete absorption, even at the high dose, where intestinal cefatrizine absorption is less efficient. Thus, it was found that the effect of saturability in the intestinal transport of cefatrizine is apparently attenuated in its overall gastrointestinal absorption because of the involvement of gastric emptying and intestinal transit time as additional physiological factors to define absorption. It was also found that a scaling factor is required to correlate the intestinal membrane transport between in vitro (in situ) and in vivo, though this remains to be verified to be utilized for developing oral drug delivery strategies and optimizing oral drug therapy.

Administration, Oral↗
PubMed1998

Fractional absorption of L-carnitine after oral administration in rats: evaluation of absorption site and dose dependency.

We evaluated the fractional absorption of L-carnitine, a gamma-amino acid essential cofactor for the transfer of long-chain fatty acids, in rats in vivo after oral administration to determine its absorption behavior. At both low (0.05 micromol/rat) and high (100 micromol/rat) doses, L-carnitine was recovered only from the region of the cecum and below at 10 h after administration. During a major shift in distribution from cecum at 10 h to feces at 24 h, there was no significant change in the total recovery at each dose, suggesting that L-carnitine absorption is negligible in the cecum and the large intestine (colon and rectum). However, the recovery of L-carnitine was incomplete and the fraction recovered was larger at the high dose than at the low dose. The fractions absorbed were estimated to be 96.7 and 33.0% for the low and high doses, respectively, as these were the fractions that disappeared from the gastrointestinal tract. These values were comparable with 100 and 42%, respectively, of bioavailability values by the pharmacokinetic analysis of plasma concentration data in our preceding study [Matsuda et al., Biopharmaceutics & Drug Disposition, in press]. These results suggest that L-carnitine is significantly absorbed only in the small intestine, without undergoing first-pass degradation, and in a dose-dependent manner presumably due to the involvement of saturable transport by L-carnitine carriers. Consistent with the suggestions in vivo, L-carnitine absorption in the closed intestinal loop in situ was concentration-dependent in the small intestine but not in the large intestine, and the apparent membrane permeability in the large intestine was smaller by an order of magnitude than that of passive transport in the small intestine. These findings support our preceding kinetic modeling strategy assuming the small intestine to be the sole absorption site, and should be of help in guiding studies on development of more efficient oral L-carnitine delivery strategies.

Administration, Oral↗
PubMed1998

First-pass metabolism of 5-fluorouracil in the perfused rat small intestine.

The first-pass intestinal metabolism of 5-fluorouracil (5-FU) was investigated by single-pass perfusion of the rat small intestine. At the low concentration of 0.06 mg/ml, the fraction of 5-FU absorbed into (i.e., appeared in) the mesenteric venous blood (Fa,b) was about 50% smaller than the fraction absorbed (disappeared) from the intestinal lumen (Fa), indicating the first-pass extraction of 5-FU in the intestinal mucosa. By addition of uracil (6 mg/ml), the Fa of 5-FU was reduced presumably by competition for the pyrimidine carrier at the process of intestinal uptake (entry into the mucosa). The Fa,b was also reduced, but to a lesser extent, resulting in insignificant first-pass extraction. These results suggest that the extraction of 5-FU in the absence of uracil is caused by metabolism and that uracil is a competitor for this pathway. When 5-FU concentration was raised from 0.06 to 0.6 mg/ml in the absence of uracil, the Fa was reduced by about 50%, consistent with the suggestion of the involvement of saturable uptake by the pyrimidine carrier, and thereafter remained unchanged at 6 mg/ml. However, since Fa,b was also reduced by a similar extent, the intestinal availability (FI=Fa,b/Fa) was unchanged at about 0.5, indicating that the intestinal first-pass extraction of 5-FU is independent of concentration with the extraction ratio (difference between unity and FI) of about 0.5 over the wide range of concentration from 0.06 to 6 mg/ml. Thus, the present study demonstrates that the significant first-pass metabolic extraction of 5-FU occurs in the mucosa of the small intestine, supporting our previous suggestion that 5-FU undergoes first-pass metabolism not only in the liver but also in the small intestine after oral administration. Considering that the oral bioavailability of 5-FU in the human (28%) is reportedly comparable with that in the rat (28%), it is likely that intestinal first-pass metabolism may be significant also in the human. Intestinal first-pass metabolism should be taken into account to explore more efficient and controlled oral 5-FU therapy.

Animals↗