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Biomedical subjects

J Uchida

Publications and source records attributed to J Uchida.

At least 19 recordsLinked to original sources

Thymidylate synthase (TS) and ribonucleotide reductase (RNR) may be involved in acquired resistance to 5-fluorouracil (5-FU) in human cancer xenografts in vivo.

A human tumour sub-line resistant to 5-fluorouracil (5-FU) was established by once a day and every 5, with at least 50 administrations of 5-FU to KM12C human colorectal xenografts in nude mice. KM12C tumours treated with 5-FU showed less sensitivity to 5-FU with an inhibition rate (IR) of 7.9%, while non-treated tumours were highly sensitive to 5-FU with an IR of 81.8%. To clarify the mechanism of 5-FU-resistance, the activities of various enzymes and gene expressions involved in the metabolism of 5-FU in both parental and 5-FU-treated KM12C tumours were measured. A 2- to 3-fold increase in thymidylate synthase (TS) activity and 4- to 5-fold decrease in ribonucleotide reductase (RNR) activity were observed in 5-FU-resistant KM12C tumours, while the activities of orotate phosphoribosyltransferase (OPRT) thymidine and uridine phosphorylases (TP,UP) and thymidine kinase (TK) were not markedly changed as a consequence of repeated treatment of KM12C tumours with 5-FU. The expression of TS mRNA was also amplified in accordance with the increased TS activity in a 5-FU-treated tumour sub-line (KM12C/5-FU) compared with that in parental tumours, but changed expressions of both RNR-R1 and RNA-R2 mRNA could not be detected in the 5-FU-resistant tumour sub-line compared with the parental tumours, suggesting possible post-transcriptional regulation of RNR. Moreover, RNR, in addition to TS and OPRT, seemed to be related to the inherent insensitivity to 5-FU in human cancer xenografts. From these results, it may be concluded that RNR activity is one of the acquired or inherent resistant factors, including TS, to 5-FU in human cancer xenografts in vivo.

Animals↗

Clinical study on 53 cases of cadaveric kidney transplantation at Osaka City University Hospital.

BACKGROUND: In this study, we examined the effects of nonimmunological factors on cadaver kidney transplant. METHODS: Fifty-three cadaver kidney transplant recipients were studied. They were divided into two groups, Group I ( donor age<60, n=38 ) and Group II ( donor age > or = 60, n=15). These patients were studied to determine whether donor age and recipient Body Mass Index (BMI) affected transplant outcome. RESULTS: The 3 and 5-year overall graft / patient survival was 80.6 / 100% and 72.7 97.3%, respectively. The best S-Cr after transplantation was significantly (p<0.05) lower in Group I compared to Group II. The 1, 5 and 8-year graft survival was significantly (p<0.05) better in Group I. In the low BMI patients of Group II, 5-year graft survival was significantly (p<0.01) better than high BMI patients. DISCUSSION: An aged cadaver donor was a risk factor for decreased posttransplant renal functions and lower graft survival. However, if a recipient with a low BMI can be selected, the outcome of cadaver kidney transplants from aged donors may be improved.

Adult↗

Identification of CD72 as a lymphocyte receptor for the class IV semaphorin CD100: a novel mechanism for regulating B cell signaling.

We have identified the lymphocyte semaphorin CD100/Sema4D as a CD40-inducible molecule by subtractive cDNA cloning. CD100 stimulation significantly enhanced the effects of CD40 on B cell responses. Administration of soluble CD100 markedly accelerated in vivo antigen-specific antibody responses. CD100 receptors with different binding affinities were detected on renal tubular cells (K(d) = approximately 1 x 10(-9)M) and lymphocytes (K(d) = approximately 3 x 10(-7)M). Expression cloning revealed that the CD100 receptor on lymphocytes is CD72, a negative regulator of B cell responsiveness. CD72 thus represents a novel class of semaphorin receptors. CD100 stimulation induced tyrosine dephosphorylation of CD72 and dissociation of SHP-1 from CD72. Our findings indicate that CD100 plays a critical role in immune responses by the novel mechanism of turning off negative signaling by CD72.

Animals↗

The class IV semaphorin CD100 plays nonredundant roles in the immune system: defective B and T cell activation in CD100-deficient mice.

The class IV semaphorin CD100/Sema4D differentially utilizes two distinct receptors: plexin-B1 in nonlymphoid tissues, such as brain and kidney, and CD72 in lymphoid tissues. We have generated CD100-deficient mice and demonstrated that they have functional defects in their immune system, without apparent abnormalities in other tissues. The number of CD5(+) B-1 cells was considerably decreased in the mutant mice, whereas conventional B cells and T cells appeared to develop normally. In vitro proliferative responses and immunoglobulin production were reduced in CD100-deficient B cells. The humoral immune response against a T cell-dependent antigen and in vivo priming of T cells were also defective in the mutant mice. These results demonstrate nonredundant and essential roles of CD100-CD72 interactions in the immune system.

Animals↗

Modified extravesical ureterocystoneostomy of the kidney transplant allograft with completely duplicated ureters.

BACKGROUND: The technique of ureterocystoneostomy for completely duplicated ureters has not yet been established. We report on a case of a living-related transplant recipient who successfully received his mother's kidney having completely duplicated ureters. METHODS/RESULTS: The recipient was a 33-year-old male patient introduced to hemodialysis due to focal glomerulosclerosis. The donor was his 60-year-old mother having left completely duplicated ureters. We adopted the modified extravesical ureterocystoneostomy technique. Postoperative drip infusion pyelography and voiding cystography of the recipient showed no evidence of urinary tract obstruction or vesicoureteral reflux. CONCLUSIONS: We conclude that this technique is suitable for the transplantation of the kidney with complete ureteral duplication.

Adult↗

Experimental postoperative adjuvant chemotherapy by UFT using primary tumor amputation model.

We evaluated the postoperative adjuvant chemotherapy by UFT using the primary tumor amputation-pulmonary metastasis model. When Lewis lung carcinoma (LLC) primary tumors on the hind foot pad grew palpable, they were amputated on two different days. In experiment (A) (earlier amputation model), micrometastases were detected on the day of amputation only by the histopathological examination. In the experiment (B) (later amputation model), nodules could be determined even by necropsy. Long-term (60-day) consecutive administration of UFT (22 mg/kg/day), which produced no body weight loss, markedly prolonged the survival period in experiment (A) (ILS: over 118%), 1 of the 15 mice being cured. UFT had a relatively weak but significant effect (67% of ILS) in schedule (B). Using the same model, we examined the inhibitory effect of UFT (2-week administration) on the number of metastatic nodules. A significant decrease of metastatic nodules was observed by UFT with both amputation schedules, but its effect was superior with schedule (A). In the same model using Colon 26 PMF-15, UFT markedly prolonged the survival period of mice (150% of ILS) and significantly decreased the metastatic nodules (86% inhibition). The dose of UFT used was relatively low, and did not significantly inhibit the growth of large tumors. However, the sensitivity to the micrometastases was high. These findings suggest that the postoperative adjuvant chemotherapy by the long-term consecutive administration of UFT would be effective for clinical cancer especially in curatively resected cases.

Amputation, Surgical↗

[Efficacy of single-dose therapy with levofloxacin for acute cystitis: comparison to three-day therapy].

To investigate the safety, efficacy and recurrence-inhibiting effect of a single dose of levofloxacin (LVFX) for the treatment of acute uncomplicated cystitis in women, 56 females with acute uncomplicated cystitis between 17 and 73 years old were studied, based on the urinary tract infection (UTI) drug efficacy evaluation. The patients were divided into two groups; in Group A a single 200 mg dose of LVFX was administered, while in Group B, 100 mg of LVFX was administered twice a day for three days. The patients were re-examined three days later. The presence or absence of recurrence was surveyed by a questionnaire 3 months after the treatment. The efficacy rate on the third day after the administration in Group A and Group B was 96.9% (32 cases) and 95.8% (24 cases), respectively, and the recurrence rate within three months after administration 17.4% (4 in 23 cases) and 5.6% (1 in 18 cases), respectively. As for adverse drug reaction, abdominal pain was seen in one case, without a clear cause-effect relationship. Although the number of cases studied was small, no significant difference was seen between the single dose group and 3-day dose group in the safety, efficacy and recurrence-inhibiting effect of the new quinolone antibacterial treatment for acute uncomplicated cystitis in women, confirming the usefulness of the single dose treatment.

Acute Disease↗

[Urethral diverticula surrounding the urethra in women: report of 2 cases].

We report two cases of female urethral diverticula. A 49-year-old woman (case 1) complained of perineal pain when she voided urine. A 36-year-old woman (case 2) complained of perineal pain. In both cases, intravenous pyerography and urethrography revealed diverticula around their urethra, and we diagnosed them with urethral diverticula which surrounded their urethra by magnetic resonance imaging. We treated them by transvaginal diverticulectomy. Case 2 was successfully treated, but the diverticulum recurred after one year in case 1. There are over 200 reported cases of female diverticula in the Japanese literature, but a urethral diverticulum surrounding the urethra is rare.

Adult↗

Mimicry of CD40 signals by Epstein-Barr virus LMP1 in B lymphocyte responses.

The effect of the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) on the activation and differentiation of normal B cells was investigated. B cells of transgenic mice expressing LMP1 under the control of immunoglobulin promoter/enhancer displayed enhanced expression of activation antigens and spontaneously proliferated and produced antibody. Humoral immune responses of LMP1 transgenic mice in CD40-deficient or normal backgrounds revealed that LMP1 mimics CD40 signals to induce extrafollicular B cell differentiation but, unlike CD40, blocks germinal center formation. Thus, these specific properties of LMP1 may determine the site of primary B cell infection and the state of infection in the natural course of EBV infection, whereas subsequent loss of LMP1 expression may affect the site of persistent latent infection.

Animals↗

Protective effect of nitric oxide against iron-induced neuronal damage.

We investigated the effect of nitric oxide (NO) on iron-induced neuronal damage. Incubation of PC12 cells after the addition of FeCl2 induced rapid increases (within 1 hr) in lipid peroxidation and a concentration (0.1-2 mM)-dependent decrease in cell viability at 48 hr, both of which were blocked by deferoxamine and 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo[1,2-a]pyrazine-3-o ne hydrochloride (MCLA) (a superoxide scavenger) but not by mannitol (a hydroxyl radical scavenger). Iron-induced cytotoxicity was also antagonized by superoxide dismutase with catalase. On the other hand, the NO donors S-nitroso-N-acetylpenicillamine (SNAP), 3-¿(+/-)-(E)-ethyl-2'-[(E)-hydroxylamino]-5-nitro-3-hexenecarbo moyl¿-pyridine (NOR-4), and 2,2'-(hydroxynitrosohydrazono)bis-ethanamine (NOC-18) decreased cell viability 48 hr after addition without increasing lipid peroxidation. However, when added with 1 mM FeCl2, NO donors including NOC-18, SNAP and NOR-4 (0.1-1 mM) inhibited lipid peroxidation in a concentration-dependent manner and suppressed cell death at lower concentrations. Addition of MCLA and NOC-18 also suppressed decreases in iron-induced [3H]thymidine incorporation. In rat brain homogenate, NOC-18 and SNAP both suppressed iron-induced lipid peroxidation. These findings suggest that NO has a dual effect on neuronal viability and can act as an antioxidant which protects neurons from iron-induced damage.

Animals↗

[Study on platinum concentration in internal iliac venous blood after iliac artery cisplatin infusion for invasive bladder cancer].

We evaluated the usefulness of internal iliac artery infusion of cisplatin (CDDP) in the M-VAC therapy for bladder cancer. CDDP (average 72 mg) was administered into the internal iliac artery with an infusion time of 15 minutes in 8 cases of bladder cancers. After the end of CDDP intra-arterial injection, we measured the total and free platinum (Pt) levels in the internal iliac venous blood and systemic venous blood. Both total and free platinum levels in the internal iliac venous blood were about 4 times higher than those in the systemic vein. No significant difference was found in total or free platinum level in the systemic blood between the intra-arterial and intra-venous infusion methods. Intra-arterial CDDP therapy is effective in the treatment of the local tumor and systemic micrometastasis.

Aged↗

Clinical results of total cystectomy for 92 patients with bladder cancer.

The survival rate of 92 patients with primary bladder cancer who had undergone total cystectomy during a 13-year period from 1984 to 1996 was examined. The mean follow-up period was 1,886 days. The 5-year survival rate was 67.9% and the 10-year survival rate was 55.1%. When survival rates were compared pathohistologically, with 81 patients with transitional cell carcinoma divided into two groups, a high-stage group including T3 and T4 patients and a low-stage group with all other patients, the cancer-specific 5-year survival rate of the low-stage group was 88.9% while that of the high-stage group was 45.4%; this difference was significant (p = 0.0002). There were also significant differences in survival rate between those with and those without regional lymph node metastasis, those with and those without lymphatic infiltration, and those with and those without vascular infiltration. However, there was no significant difference in survival rate for the 34 patients with T3 or T4 disease when those with or without chemotherapy and/or radiation therapy were compared.

Adult↗

Ca(2+)-dependent enhancement of [3H]noradrenaline uptake in PC12 cells through calmodulin-dependent kinases.

Ca(2+)-dependent regulation of [3H]noradrenaline ([3H]NA) uptake through the NA transporter was studied using PC12 cells. Preincubation for 10 min in the presence of 0.3-10 mM ca2+ in Krebs-Ringer (KR) buffer induced marked enhancement of the uptake (at 1 mM Ca2+, 6.6 times greater than that observed in the absence of Ca2+), which reflected both an increase in Vmax and a decrease in K(m) of the uptake process. Preincubation with 1 mM Ca2+ also induced a significant increase in the Bmax and Kd of [3H]desipramine binding. The uptake was still enhanced after washing cells with Ca(2+)-free buffer following preincubation with 1 mM Ca2+. 1-[N, O-bis(5-Isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine (KN-62), 2-[N-(2-hydroxyethyl)-N-(4-methoxybenzenesulfonyl)]amino-N-(4-c hlo rocinnamyl) -N-methylbenzylamine (KN-93) (inhibitors of Ca2+/calmodulin-dependent kinase II), N-(6-aminohexyl)-5-chloro-1-naphthalenesulonamide (W-7) (a calmodulin antagonist), wortmannin (a myosin light chain kinase inhibitor) significantly reduced Ca(2+)-dependent enhancement of the uptake. Mycalolide B (an inhibitor of actin-myosin interaction) also inhibited the enhancement. Although calphostin C (a protein kinase C (PKC) inhibitor) did not affect the enhancement, 12-o-tetradecanoylphorbol 13-acetate (TPA) inhibited the uptake. A synthetic peptide with a sequence (KKVIYKFFS579 IRGSLW) contained in the intracellular COOH-terminal domain of a rat NA transporter was phosphorylated by purified brain Ca2+/calmodulin-dependent protein kinase II. These results suggest that Ca(2+)-dependent enhancement of the [3H]NA uptake in PC12 cells are mediated by activation of calmodulin-dependent protein kinases, probably through stimulation of translocation of the NA transporter to the plasma membrane and/or direct phosphorylation of the transporter itself.

Actins↗

Glutamate-stimulated proliferation of rat retinal pigment epithelial cells.

We investigated the effects of glutamate on cell proliferation and the expression of basic fibroblast growth factor (bFGF) and its receptor (FGF-R1) mRNA in cultured rat retinal pigment epithelial (RPE) cells. The number of primary RPE cells was significantly higher after treatment with 0.2 to 1.0 mM glutamate (maximum at 1.0 mM) for 7 days than in controls. Glutamate-stimulated cell proliferation was abolished by (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801), but not by 6,7-dinitroquinoxaline-2,3-dione or L(+)-2-amino-3-phosphonopropionic acid. Proliferation was increased to a similar extent by N-methyl-D-aspartate (NMDA), but not by kainate, alpha-amino-3-hydroxy-3-methyl-4-isoxazolepropionic acid or trans-(+/-)-1-amino-1,3-cyclopentanedicarboxylic acid. NMDA-receptor-like immunoreactivity was detected in most cells cultured. Treatment of cells with glutamate increased the level of bFGF mRNA and, to a lesser extent, that of FGF-R1 mRNA, which peaked 2 and 4 days, respectively, after glutamate was added. The increase in bFGF mRNA induced by glutamate was inhibited by MK-801. These findings suggest that glutamate might stimulate proliferation of RPE cells through activation of NMDA receptors and expression of bFGF and further suggest that glutamate may be involved in the proliferative changes of RPE cells in retinal wound healing.

Animals↗

Anticancer activity and toxicity of S-1, an oral combination of tegafur and two biochemical modulators, compared with continuous i.v. infusion of 5-fluorouracil.

S-1 is an oral combined form of 1 M tegafur [a prodrug of 5-fluorouracil (5-FU)], 0.4 M 5-chloro-2,4-dihydroxypyridine (a reversible inhibitor of dihydropyrimidine dehydrogenase) and 1 M potassium oxonate (an inhibitor of orotate phosphoribosyltransferase). S-1 has been shown to exert a potent antitumor effect with low gastrointestinal toxicity in experimental tumor models. We have therefore compared the antitumor effect of oral S-1 with that of continuous infusion of 5-FU in rats bearing transplants of human and murine tumors. Almost complete inhibition of the tumor growth was obtained on 7 day schedules in Yoshida sarcoma-bearing rats by consecutive administration of 30 mg/kg/day of oral S-1 and 40 mg/kg/day infusion of 5-FU. However, a significant difference between the incidence of toxicities of S-1 and 5-FU, including body weight loss and diarrhea, was noted. The rats given the 5-FU infusion had marked weight loss and severe diarrhea, while those given oral S-1 had neither. Although about 50% inhibition of the tumor growth was attained with 15 mg/kg/day of oral S-1 and 30 mg/kg/day infusion of 5-FU in nude rats with xenografted human colon cancer (KM12C), the rate of body weight loss in the 5-FU-treated group was distinctly higher than in the S-1-treated group. The ratio of the 5-fluoronucleotide concentrations in gastrointestinal tissue to that in the tumor was lower in the S-1-treated rats than in the 5-FU-treated rats. In conclusion, the results suggest that oral S-1 might be more effective in the treatment of cancer patients than continuous infusion of 5-FU, from the standpoint of antitumor potency and toxicity.

Administration, Oral↗

Renal cell carcinoma of extraordinarily large size: a case report.

One of our patients was a 66-year-old woman with a T2 renal cell carcinoma weighing 3900 g. Two years after radical nephrectomy the woman was alive and well. A survey of Japanese medical literature revealed that patients with renal cell carcinomas weighing more than 2000 g have an unexpectedly favorable prognosis with a 5-year survival rate of 76.9%.

Aged↗

Renal endothelin in FK506-induced nephrotoxicity in spontaneously hypertensive rats.

FK506, a major immunosuppressive agent, often causes nephrotoxicity accompanied by renal vasoconstriction. It is recognized that endothelin (ET) plays a role in the cyclosporin A-induced nephrotoxicity, but the involvement of ET in the FK506-induced renal dysfunction is still poorly understood. We elicited nephrotoxicity by daily administration of FK506 in spontaneously hypertensive rats, and we examined the renal gene expression of ET and its receptors and the effects of an ET receptor antagonist on FK506-induced renal dysfunction. FK506 administration (4 mg/kg/day, i.m.) for 14 days induced nephrotoxicity, including a renal vasoconstriction and a decrease in glomerular filtration rate. The renal dysfunction was accompanied by an increase in ET-1 mRNA levels, while ET(B)-receptor mRNA was unaffected. Continuous administration of an ET(A)/ET(B) antagonist, TAK-044 (3 mg/day, s.c.), which effectively blocked systemic and renal vascular responses to exogenously administered ET-1, partially attenuated the FK506-induced renal vasoconstriction. However the reduced glomerular filtration rate were not affected by TAK-044. Thus, although enhanced gene expression of ET-1 in the kidney is involved in the renal vasoconstriction, ET does not play a major role in the FK506-induced renal dysfunction.

Animals↗