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K Ebihara

Publications and source records attributed to K Ebihara.

At least 55 records · Page 3Linked to original sources
PubMed1996

Conserved motifs in prokaryotic and eukaryotic polypeptide release factors: tRNA-protein mimicry hypothesis.

Translation termination requires two codon-specific polypeptide release factors in prokaryotes and one omnipotent factor in eukaryotes. Sequences of 17 different polypeptide release factors from prokaryotes and eukaryotes were compared. The prokaryotic release factors share residues split into seven motifs. Conservation of many discrete, perhaps critical, amino acids is observed in eukaryotic release factors, as well as in the C-terminal portion of elongation factor (EF) G. Given that the C-terminal domains of EF-G interacts with ribosomes by mimicry of a tRNA structure, the pattern of conservation of residues in release factors may reflect requirements for a tRNA-mimicry for binding to the A site of the ribosome. This mimicry would explain why release factors recognize stop codons and suggests that all prokaryotic and eukaryotic release factors evolved from the progenitor of EF-G.

Amino Acid Sequence↗
PubMed1996

Biopharmaceutical evaluation of the liposomes prepared by rehydration of freeze-dried empty liposomes (FDELs) with an aqueous solution of a drug.

We have evaluated a method for preparation of a dispersion of liposomes encapsulating a drug, namely rehydration of freeze-dried empty (not containing drug) liposomes with an aqueous drug solution (FDEL method). In the present study, we characterized and compared this method with the conventional method using a lipid composition of DPPC-DPPG-cholesterol in a molar ratio of 27:3:20. Two hydrophilic compounds, [3H]-inulin and [3H]-mannitol, were used as model drugs. Liposomal preparations by the FDEL method had an encapsulation efficiency of 2.9 and 6.7% for [3H]-inulin and [3H]-mannitol, respectively, when rehydrated and incubated at 70 degrees C. Since non-specific adsorption of these markers to liposomal membrane is negligible, this method produces liposomes which encapsulate a drug in the intravesicular space. One-tenth of the marker encapsulated in the liposomes prepared by the FDEL method (F-liposomes) was released very rapidly on incubation with rat plasma, followed by the slow release of the remaining fraction thereafter. No such rapid-release phase was observed for the liposomes prepared by the conventional method (C-liposomes). This suggests the existence of two types of encapsulation, loose encapsulation and tight encapsulation, in F-liposomes at least. Pharmacokinetic parameters of marker encapsulated tightly in F-liposomes were comparable to those in C-liposomes. It is likely that amphipathic drugs such as doxorubicin are incorporated into liposomes more easily than inulin and mannitol when formulated by the FDEL method. These results therefore suggest that the FDEL method is useful in the preparation of a liposomal formulation of a drug.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1996

Intron retention generates a novel isoform of the murine vitamin D receptor that acts in a dominant negative way on the vitamin D signaling pathway.

We identified and characterized a novel rat vitamin D receptor isoform (rVDR1), which retains intron 8 of the canonical VDR (rVDR0) during alternative splicing. In this isoform protein directed by the stop codon in this newly identified exon, a part of the ligand binding domain (86 amino acids) is truncated at the C-terminal end but contains 19 extra amino acids. The rVDR1 transcript was expressed at a level 1/15 to 1/20 of that of rVDR0 in the kidney and intestine in adult rats but not in embryos. The recombinant rVDR1 protein showed no ligand binding activity. Homo- and heterodimers of the recombinant rVDR0 and rVDR1 proteins bound to a consensus vitamin D response element (VDRE) but not to consensus response elements for thyroid hormone and retinoic acid. However, unlike rVDR0, rVDR1 did not form a heterodimeric complex with RXR on the VDRE. A transient expression assay showed that this isoform acted as a dominant negative receptor against rVDR0 transactivation. Interestingly, the dominant negative activities of rVDR1 differed among VDREs. Thus, the present study indicates that this new VDR isoform negatively modulates the vitamin D signaling pathway, through a particular set of target genes.

Alternative Splicing↗
PubMed1996

Cyclosporin A stimulation of glucose-induced insulin secretion in MIN6 cells.

Effects of the immunosuppressant cyclosporin A (CsA), a specific inhibitor of Ca2+/calmodulin-dependent protein phosphatase (PP2B), were examined with regard to the induction of insulin secretion from MIN6 cells, a glucose-responsive cell line derived from mouse insulinoma. CsA had no effect on basal insulin secretion from MIN6 cells, but did increase glucose-, tolbutamide-, and KCl-induced insulin secretion. Treatment of the cells with CsA resulted in a dose-dependent increase in insulin secretion, which was maximal at 3 microM. CsA inhibited PP2B activity in a dose-dependent manner, and the increase in insulin secretion correlated with the decrease in PP2B activity. In 32P-labeled cells, treatment with CsA for 30 min increased phosphorylation of synapsin I-like protein by 50 +/- 5.7%. As revealed by one-dimensional phosphopeptide mapping of 32P-labeled synapsin I-like protein, treatment with CsA for 30 min increased phosphorylation of site II of synapsin I-like protein by 59 +/- 8%, which is phosphorylated by calmodulin kinase II. Messenger RNAs, which hybridize with complementary DNAs of calcineurin A and B subunits from rat brain, were detected in MIN6 cells. Western blot analysis showed a 61-kDa band, which interacts with rat brain calcineurin A antibody. Similar increases in secretagogue-induced insulin secretion with CsA were observed for HIT-T15 cells. These results suggest that CsA stimulates glucose-induced insulin secretion by inhibiting the activity of PP2B, an event that may be involved in mechanisms governing glucose-induced insulin secretion via dephosphorylation of synapsin I-like protein in MIN6 cells.

Animals↗
PubMed1995

Transcriptional activity of a fluorinated vitamin D analog on VDR-RXR-mediated gene expression.

The transcriptional activity of the hexafluorinated derivative of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3], 26,26,26,27,27,27-hexafluoro-1,25-dihydroxyvitamin D3 [F6-1,25-(OH)2D3], was examined in cultured cells by a transient expression assay (CAT assay) using expression vectors for the rat nuclear vitamin D3 receptor (VDR) and the rat 9-cis-retinoic acid receptor (RXR beta), and a reporter plasmid containing a consensus vitamin D3 response element (VDRE) consisting of two directly repeated AGGTCA motifs spaced by 3 bp (DR3). At physiological concentrations, the transcriptional activity of F6-1,25-(OH)2D3 was 2-4 times more potent than that of 1,25-(OH)2D3 in both nontarget (HeLa) and target (UMR106) cells for 1,25-(OH)2D3. The transcriptional activity of F6-1,25-(OH)2D3 was also higher when the endogenous target gene (osteopontin), which has a VDRE related to the DR3 in its promoter, was induced. A gel-shift assay using DR3 as a probe and in vitro synthesized receptors showed that the ligand-induced DNA binding of VDR required RXR to form a heterodimer. Moreover, in this assay we found that F6-1,25-(OH)2D3 induced the receptor-DNA complex at a 10-fold lower concentration than 1,25-(OH)2D3 without influencing the dissociation kinetics. However, the binding affinity of F6-1,25-(OH)2D3 for VDR was slightly lower than that of 1,25-(OH)2D3. The increased DNA binding of ligand-bound VDR by introducing hexafluorines into 1,25-(OH)2D3 may potentiate the transcriptional activity. Thus, the higher biological activity of F6-1,25-(OH)2D3 may be exerted at least in part by enhanced transcriptional activity.

Animals↗
PubMed1993

Dietary fiber and fat-derivatives prevent mineral oil toxicity in rats by the same mechanism.

The inclusion of 8% mineral oil in a fat-free diet causes severe growth retardation in rats. In the present study, this growth retardation was found to be primarily due to the reduction in nutrient intake, but not to the exacerbation of essential fatty acid deficiency. In addition, the growth retardation caused by mineral oil ingestion was prevented by the concurrent inclusion of 10% water-insoluble dietary fiber [gobo fiber prepared from Arctium lappa L. (gobo in Japanese) or cotton cellulose powder] or 5% fatty acids (C12-C18) as well as glycerol monostearate. The prevention of growth retardation by these substances was due to their ability to inhibit mineral oil absorption from the intestinal lumen.

Absorption↗
PubMed1993

[The clinical significance of carbohydrate antigen 19-9 (CA19-9) in transitional cell cancer of urinary tract].

For the purpose of evaluating the utility of CA19-9 determination in transitional cell cancer (TCC) of the urinary tract, its serum value, tissue level and, immunohistochemical study, and follow up study, with high serum value were examined in 43 cases with TCC and 13 cases of control. 1. Serum values were 19.1 U/ml in the control group and 198 U/ml in the tumor group. Though those of tumor were higher than those of the control group, there is no statistical difference between both groups. The cases with abnormally high value were observed in 13.7% of the control group, 13.8% of the bladder cancer, and 57.1% of the upper urinary tract cancer. 2. Tissue levels were 816 U/g wet tissue in the control group and 13,000 U/g wet tissue in the tumor group, showing a significantly higher value (p < 0.01) in the tumor group, statistically. 3. Immunohistochemical study were positive in 4.0% of the control group and 88.4% of the tumor group. 4. There is a significant correlation between serum values and tissue levels (p < 0.05, r = 0.483). 5. The serum values did not correlated with the staining property, tumor size, grade, and stage. 6. The tissue levels correlated with the tumor size, but did not correlate with the staining property, grade, and stage. 7. In the follow-up study of cases with high value, those, who had not attained postoperative normalization, died of recurrent carcinoma. In cases showing an elevation despite postoperative normalization, too, all showed recurrence. Only those, whose value were normalized and remained at the normal range, are living without metastasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1991

Rapid diagnosis of cytomegalovirus infections by direct immunoperoxidase staining with human monoclonal antibody against an immediate-early antigen.

Direct immunoperoxidase technique using a horseradish peroxidase (HRP)-conjugated Fab' fragment of human monoclonal antibody (humab C7), designated HRP-C7, was evaluated as a rapid diagnosis of cytomegalovirus (CMV) infection. A total of 138 clinical specimens consisting of 124 urine samples and 14 oral swabs were examined for CMV by the direct HRP-C7 staining in comparison with conventional virus isolation. The number of CMV-positive samples by each method was 40 (29.0%) for the former and 37 (26.8%) for the latter, respectively. By HRP-C7 staining, CMV was identifiable within 24 hr after inoculation. By conventional isolation method, an average of 10.3 days had passed before cytopathic effect characteristic of CMV appeared in the cell culture. Some false-positive and false-negative cases were discussed in relation to toxicity of urine samples, storage of the samples, and amount of CMV in the sample. The sensitivity and specificity of HRP-C7 method against conventional isolation method were 89.2% and 93.1%, respectively. Thus, HRP-C7 staining is useful for a rapid diagnosis of CMV infections.

Antibodies, Monoclonal↗
PubMed1991

[Clinical studies of bacteriuria in renal transplantation recipients. Correlation with pyuria and symptomatic genitourinary tract infection].

The clinical state of bacteriuria and its correlation with pyuria and symptomatic genitourinary tract infection (GUTI) were studied in 42 renal transplantation recipients who were followed up in the Kidney Center of Tokyo Women's Medical College over 6 months and who showed bacteriuria more than 3 times between January and December in 1987. The results were as follows. 1) Of the 42 recipients, bacteriuria was found less than 5 times in 19 patients, 6 to 10 times in 18 patients and more than 11 times in 5 patients. There was a tendency for the same bacteria to be isolated several times from the same patient. The most commonly isolated bacterias were Enterobacter, Enterococcus, Serratia and E. coli. 2) Bacteriuria was accompanied by pyuria in 33 patients (79%) and by symptomatic GUTI in 12 patients (29%). Bacteriuria without pyuria was shown in 9 patients (21%) without symptomatic GUTI and it was suggested that bacteriuria did not result in graft hypofunction after two years. 3) Of 16 patients with bacteriuria accompanied by pyuria, symptomatic GUTI occurred in 9 patients (56%). Of these, one patient was found to have VUR of the transplanted kidney, another was found to have VUR of the native kidney, and a third patient died due to interstitial pneumonitis presumably as a result of overimmunosuppression. Transplantation recipients with bacteriuria accompanied by pyuria develop symptomatic GUTIs frequently and should be treated with proper antibacterial agents. When bacteriuria continues, further examination should be performed for an organic disease of the urinary tract or an overimmunosuppressed state. When a patient shows bacteriuria without pyuria, chemotherapy is not needed and it is sufficient to observe the course carefully.

Adult↗
PubMed1991

Spontaneous rupture of renal angiomyolipoma.

We report a case of renal angiomyolipoma with retroperitoneal hemorrhage treated by enucleation in a 47 year-old male. The mass in the anterior side of the left kidney, revealed by sonography and CT, was diagnosed as angiomyolipoma with a retroperitoneal hematoma caused by its spontaneous rupture. Removal of hematoma and enucleation of the tumor were performed after the diagnosis. Diagnosis and treatment of ruptured renal angiomyolipoma are discussed.

Hemangioma↗
PubMed1990

Leiomyoma of the bladder causing bilateral hydronephrosis: a case report.

We report a case of bladder leiomyoma with marked bilateral hydronephrosis caused by chronic urinary retention. Surgical finding was that the mass was smooth, fist-sized and had a thin stalk connected to the bladder wall. The tumor was completely removed. Histopathological diagnosis was leiomyoma of the bladder and the post-operative course was uneventful.

Aged↗
PubMed1989

Interaction of bile acids, phospholipids, cholesterol and triglyceride with dietary fibers in the small intestine of rats.

Certain dietary fibers have been reported to lower plasma cholesterol by binding bile acids and reducing their recycling through the enterohepatic circulation. In addition, certain fibers may delay the digestion and absorption of fat. In the present study, the interaction of bile acids with guar gum (GG), konjac mannan (KM) and chitosan (CH) was determined. Rats were fed during a 20-min period a test meal containing either 5% cellulose (CE), GG, KM or CH and also containing 14C-labeled triolein and 3H-labeled cholesterol. The group fed CE served as control, since CE does not bind bile acids or phospholipids in vivo. Two hours after presentation of the test meal, rats were killed and the stomach and small and large intestine removed. All four groups ate the same amount of the test meal, about 1.9 g. The aqueous phase of the small intestinal contents was separated by ultracentrifugation, and the amount (mumol) of bile acids and phospholipids in the total intestinal contents and in the aqueous phase was estimated. The ratio of bile acids in the aqueous phase to that in total intestinal contents was significantly higher in the GG and KM groups and significantly lower in the CH group than that in the CE group, demonstrating that the bile acids are bound or trapped by each of these fiber sources. Only CH appeared to bind phospholipids, reducing the proportion in the aqueous phase compared to that in the CE group.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1989

[Efficacy of ganciclovir against cytomegalovirus nephropathy after kidney transplantation].

A 32-year-old man who had received a kidney transplant from a living related donor, contracted cytomegalovirus (CMV) pneumonitis in the 8th month. He was treated with human interferon-beta and cured of the pneumonitis. After that, his serum creatinine value increased gradually. Renal biopsy revealed the cells with intranuclear inclusion bodies in the renal tubulus and the cells were positive for CMV antigens by direct immunofluorescence test using FITC-labeled mouse monoclonal antibody against an early antigen. He was hospitalized with persistent CMV viruria and treated with ganciclovir. Ganciclovir was administered daily in doses of 3 mg per kg per day for 32 days by intravenous drip infusion and thereafter the same dose was given 3 times weekly for 8 weeks. His urine was positive for CMV before the ganciclovir treatment and became negative on the 31st day after the treatment. The anti-CMV effect of ganciclovir was evidenced by gradual decrease in titer (PFU) of infectious CMV in the urine samples. His serum creatinine value decreased from 3.2 mg/dl to 2.8 mg/dl, and no adverse effect was noticed. Thus, ganciclovir is considered to be efficacious against CMV infections in kidney transplant recipients.

Adult↗
PubMed1989

[Infectious diseases in kidney transplant recipients treated with cyclosporin].

Cyclosporin (CYA) is now recognized as an effective immunosuppressant to lead to a marked improvement in graft survival in organ transplant recipients. Although the incidence of infection in the CYA group has been decreased compared with that in the azathioprine group, infectious diseases in 400 kidney transplant recipients treated with CYA were noted in our single center. Treatment strategy for infectious diseases: Antibiotics and/or gamma-Globulin were administered to all recipients with bacterial infections. Aciclovir was added in recipients with herpes simplex virus (HSV) infection or varicella zoster virus (VZV) infection. Human interferon-beta (HuIFN-beta) was used in recipients who had life-threatening viral infection, especially cytomegalovirus (CMV) pneumonitis. Glycyrrhizin was used for acute hemorrhagic cystitis and nephropathy due to adenovirus (AV). Trimethoprim sulfamethoxazole and/or pentamidine were added in recipients complicated with Pneumocystis carinii (Pc) pneumonitis or in order to prevent Pc pneumonitis. Infectious diseases: One hundred and six recipients had infectious diseases 129 times in this series, seventy-six percent of all infections occurred during the first 4 months after the transplantation. Urinary tract infection (UTI), herpes zoster and pulmonary infection were the most common infectious diseases, occurring in 28.7%, 24.0% and 23.2%, respectively. Septicemia or bacteremia developed in 9 recipients, secondary to UTI in 8 and to surgical wound infection in one. Sixty-one symptomatic viral infections occurred in 57 recipients. A total of 5 recipients (1.3%) died of interstitial pneumonitis. Infectious organisms: Viral and bacterial infections were most common, occurring in 47.3% and 41.9%, respectively. Viral species detected in these recipients with the frequency were HSV 14 times, CMV 9 times, VZV 31 times and AV 7 times. 1) The incidence of viral infections in kidney transplant recipients treated with CYA is relatively high compared to bacterial infections. 2) HuIFN-beta therapy is effective in the treatment of serious opportunistic herpes virus infections, especially CMV pneumonitis. 3) Glycyrrhizin therapy is effective in the treatment of acute hemorrhagic cystitis and nephropathy due to AV and hepatic dysfunction. 4) Aerosolised pentamidine therapy is very useful for prophylaxis of Pc pneumonitis.

Adolescent↗
PubMed1989

[Postoperative pyuria after TUR-P: the study of postoperative pyuria by using NFLX].

The postoperative duration of pyuria was studied in 35 patients who underwent transurethral resection of the prostate (TUR-P). The average postoperative duration of pyuria was 58.0 +/- 23.6 days. The age over 70 years, preoperative indwelling of urethral catheter and the preoperative urinary tract infection did not make the duration of pyuria longer. The volume of resected prostatic tissue over 20 g and the existence of diabetes mellitus make it significantly longer. It is effective and safe to use a low-dose antibacterial agent such as NFLX which has a broad spectrum and hardly develops bacterial resistance after TUR-P. It is suggested unnecessary to change the anti-bacterial agent even when pyuria continues.

Aged↗