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Biomedical subjects

Y Yasuda

Publications and source records attributed to Y Yasuda.

At least 19 recordsLinked to original sources
PubMed1999

Evaluation of cationic liposome suitable for gene transfer into pregnant animals.

Cationic liposome-mediated in vivo gene transfer represents a promising approach for somatic gene therapy. To assess the most suitable liposome for gene delivery into a wide range of organs and fetuses in mice, we have explored several types of cationic liposomes conjugated with plasmid DNA carrying the beta-galactosidase gene through intravenous injection into pregnant animals. Transduction efficiency was assessed by Southern blot analysis and expression of the transferred gene was evaluated by enzymatic demonstration of beta-galactosidase activity. Through the analysis of several types of recently synthesized cationic liposome/lipid formulations, DMRIE-C reagent, a liposome formulation of the cationic lipid DMRIE (1, 2-dimyristyloxypropyl-3-dimethyl-hydroxy ethyl ammonium bromide) and cholesterol in membrane-filtered water met our requirements. When the plasmid DNA/DMRIE-C complexes were administered intravenously into pregnant mice at day 11.5 post coitus (p.c.), transferred genes were observed in several organs in dams and were expressed. Furthermore, although the copy numbers transferred into embryos were low, we observed reporter gene expression in the progeny.

Animals↗
PubMed1999

Intranasal or subcutaneous co-administration of recombinant cholera toxin B subunit stimulates only a slight or no level of the specific IgE response in mice to tetanus toxoid.

Whether recombinant cholera toxin B subunit (rCTB) co-administered intranasally or subcutaneously with aluminium-non-adsorbed tetanus toxoid (nTT) can induce the production of tetanus toxoid (TT)-specific IgE antibodies in mice was investigated compared with aluminium-adsorbed tetanus toxoid (aTT) administered intranasally or subcutaneously. Mice immunized intranasally or subcutaneously with nTT together with rCTB showed a high level of TT-specific serum IgG antibody response and no or a slight level of TT-specific serum IgE antibody response. On the other hand, in mice vaccinated intranasally or subcutaneously with aTT alone, higher levels of TT-specific IgG and IgE antibodies were induced in comparison with intranasal or subcutaneous inoculation of nTT together with rCTB. These results suggest that intranasal or subcutaneous co-administration of rCTB with nTT is better than intranasal or subcutaneous administration of aTT to avoid IgE-mediated allergic reactions.

Adjuvants, Immunologic↗
PubMed1999

Pancreatic bladder or double gallbladder draining into pancreatic duct?

We report a case of pancreatic bladder which could also be interpreted as double gallbladder draining into the pancreatic duct. A 6-year-old Japanese boy underwent a cholecystectomy of the smaller bladder under the diagnosis of duplication of the gallbladder, leaving the normal gallbladder and an unremarkable biliary ductal system. The smaller bladder was histologically similar to the gallbladder tissue. At age 25, relaparotomy was performed. It was confirmed that the residual aberrant duct from the smaller bladder joined directly with the duct of Wirsung and that the patient had fusiform dilatation of the extrahepatic bile duct. The extrahepatic portion of the bile duct was excised along with the "normal" gallbladder and the residual aberrant duct. The present anomaly seems to validate the designation of pancreatic bladder whose cystic duct joined directly with the pancreatic duct, but may also be explained from the view point of double gallbladder.

Bile Ducts↗
PubMed1999

Preoperative assessment of congenital bile duct dilatation using intraductal US.

BACKGROUND: Although congenital bile duct dilatation is frequently associated with biliary tract cancer, conventional cholangiography often does not demonstrate small ductal tumors. This is the first prospective study of the value of intraductal ultrasonography (US) in the examination of the extrahepatic bile ducts in patients with congenital bile duct dilatation. METHODS: Intraductal US via a transpapillary route was used in consecutive patients with congenital bile duct dilatation. A 2.0 mm diameter, 20 MHz frequency catheter probe was used. The images were correlated with the results of histologic examination of the resection specimens. RESULTS: Intraductal US was performed successfully via the transpapillary route in 8 of 10 patients. In the other 2 patients, the percutaneous transhepatic route was used. In the 6 patients with cylindrical dilatation, intraductal US demonstrated the entire extrahepatic bile duct. In 1 patient, it showed a bile duct cancer not demonstrated by cholangiography. In 2 of the 4 patients with cystic dilatation, intraductal US did not demonstrate the entire extrahepatic bile duct because of the low penetration depth of the probe. Percutaneous transhepatic cholangioscopy was required in these patients. CONCLUSIONS: Intraductal US is useful for demonstrating cancers in the extrahepatic bile ducts in patients with congenital cylindrical ductal dilatation.

Adult↗
PubMed1999

Role of interleukin-12 in the development of acute graft-versus-host disease in bone marrow transplant patients.

Interleukin-12 (IL-12) is a crucial cytokine regulating cell-mediated immunity, and may contribute to the development of graft-versus-host disease (GVHD). We investigated serum IL-12 concentrations, interferon gamma (IFN-gamma) production by peripheral blood lymphocytes (PBL) from allogeneic stem cell recipients after IL-12 plus anti-CD3 monoclonal antibody (mAb) stimulation. We also investigated IL-12 production by peripheral macrophages (Mphi) after lipopolysaccharide (LPS) stimulation from allogeneic stem cell recipients and patients receiving donor leukocyte transfusions (DLT) for treatment or prophylaxis of leukemia relapse and Epstein-Barr virus (EBV) lymphoproliferative disease (LPD). PBL from acute GVHD patients produced high IFN-gamma levels after IL-12 plus anti-CD3 mAb stimulation, whereas PBL from patients without acute GVHD produced low levels of IFN-gamma. However, serum IL-12 concentrations were low in both groups. Peripheral Mphi IL-12 production increased in patients who developed acute GVHD compared to patients without acute GVHD. Five patients receiving DLT for treatment or prophylaxis of leukemia relapse developed acute GVHD. IFN-gamma production by PBL stimulated by IL-12 plus anti-CD3 mAb increased, while IL-12 production by peripheral Mphi stimulated by LPS was very high after the development of acute GVHD. However, serum IL-12 concentration remained low. Three patients receiving DLT for EBV-LPD did not develop acute GVHD with no increase of IFN-gamma and IL-12 production. These results indicate that IL-12 may play an important role in the development of acute GVHD after allogeneic stem cell grafting or DLT, and increased IL-12 production by Mphi occurs with various stimuli, including LPS.

Acute Disease↗
PubMed1999

Limitation of cholangiography in assessing longitudinal spread of extrahepatic bile duct carcinoma to the hepatic side.

BACKGROUND: Preoperative assessment of longitudinal spread of bile duct carcinoma (BDC) to the hepatic side remains a difficult problem for diagnostic imaging. METHODS: We studied the accuracy of cholangiography in assessing BDC. In 54 patients with extrahepatic bile duct cancer, cholangiographic findings were compared retrospectively with the histological findings of the resected specimens. RESULTS: Histological examination of specimens indicated longitudinal spread of the tumour to the hepatic side in 22 of 54 patients. The accuracy of cholangiography in assessing the extent of the longitudinal spread was only 34/54 (63%). When the cholangiographic images showed a main tumour with a collapsed edge, there was a significantly higher frequency of longitudinal spread compared with tumours with sharp edges (P< 0.05). In contrast, the accuracy of mapping biopsy under percutaneous transhepatic cholangioscopy (n=24) was 83%. CONCLUSIONS: Cholangiography cannot accurately assess the extent of the longitudinal spread of bile duct cancer. When cholangiographic images show a tumour with a collapsed edge, preoperative or intraoperative histological examination is essential to determine a suitable surgical line.

Adenocarcinoma↗
PubMed1999

Influence of hemodialysis membrane type on pentosidine plasma level, a marker of "carbonyl stress".

UNLABELLED: Influence of hemodialysis membrane type on pentosidine plasma level, a marker of "carbonyl stress." BACKGROUND: The accumulation of advanced glycation end products (AGEs) in uremia has been ascribed to the retention of carbonyl precursors of AGEs. Pentosidine plasma level has been identified as a surrogate marker of carbonyl precursors ("carbonyl stress"). The influence of hemodialysis (HD) membrane type and residual diuresis on carbonyl stress has not been studied. METHODS: We measured protein-linked and free plasma pentosidine (a surrogate marker of carbonyl stress) by high-performance liquid chromatography in patients on HD with low-flux cellulose (N = 29), high-flux polysulfone (PS; N = 57), polymethylmethacrylate (PMMA) (N = 25), and AN69 (N = 15). RESULTS: Both protein-linked and free pentosidine were similar on low-flux cellulose, high-flux PMMA, and AN69, but were lower (P < 0.01) on high-flux PS. Pentosidine levels were virtually identical on Fresenius and Asahi PS in Japanese and Belgian patients. By multivariate analysis, only the type of HD membrane and residual diuresis proved to be independent determinants (P < 0.001) of pentosidine levels. During a single HD session, the clearance of free pentosidine was similar with all membranes. In three patients who were switched from AN69 to PS, the protein-linked pentosidine level dropped to the control level after resumption of the AN69 membrane. CONCLUSIONS: Both HD membrane type and residual diuresis are independent determinants of pentosidine plasma level, which is a marker of carbonyl stress.

Aged↗
PubMed1999

Characterization of new fluorogenic substrates for the rapid and sensitive assay of cathepsin E and cathepsin D.

Cathepsin E and cathepsin D are two major intracellular aspartic proteinases implicated in the physiological and pathological degradation of intra- and extracellular proteins. In this study, we designed and constructed highly sensitive synthetic decapeptide substrates for assays of cathepsins E and D based on the known sequence specificities of their cleavage sites. These substrates contain a highly fluorescent (7-methoxycoumarin-4-yl)acetyl (MOCAc) moiety and a quenching 2,4-dinitrophenyl (Dnp) group. When the Phe-Phe bond is cleaved, the fluorescence at an excitation wavelength of 328 nm and emission wavelength of 393 increases due to diminished quenching resulting from the separation of the fluorescent and quenching moieties. The first substrate, MOCAc-Gly-Lys-Pro-Ile-Leu-Phe-Phe-Arg-Le u-Lys(Dnp)gamma-NH2, in which the Lys-Pro combination at positions P5 and P4 was designed for specific interaction with cathepsin E, is hydrolyzed equally well by cathepsins E and D (kcat/Km = 10.9 microM(-1) x s(-1) for cathepsin E and 15.6 microM(-1) x s(-1) for cathepsin D). A very acidic pH optimum o was obtained for both enzymes. The second substrate, MOCAc-Gly-Lys-Pro-Ile-Ile-Phe-Phe-Arg-Le u-Lys(Dnp)gamma-NH2, in which the isoleucine residue at position P2 was meant to increase the specificity for cathepsin E, is also hydrolyzed equally by both enzymes (kcat/Km = 12.2 microM(-1) x s(-1) for cathepsin E and 16.3 microM(-1) x s(-1) for cathepsin D). The kcat/Km values for both substrates are greater than those for the best substrates for cathepsins E and D described so far. Unfortunately, each substrate shows little discrimination between cathepsin E and cathepsin D, suggesting that amino acids at positions far from the cleavage site are important for discrimination between the two enzymes. However, in combination with aspartic proteinase inhibitors, such as pepstatin A and Ascaris pepsin inhibitor, these substrates enable a rapid and sensitive determination of the precise levels of cathepsins E and D in crude cell extracts of various tissues and cells. Thus these substrates represent a potentially valuable tool for routine assays and for mechanistic studies on cathepsins E and D.

Amino Acid Sequence↗
PubMed1999

Expression of a germination-specific amidase, SleB, of Bacilli in the forespore compartment of sporulating cells and its localization on the exterior side of the cortex in dormant spores.

A germination-specific amidase of bacilli is a major spore-lytic enzyme that is synthesized with a putative signal sequence and hydrolyses spore cortex in situ. The sleB gene encoding this amidase in Bacillus subtilis and Bacillus cereus was expressed in the forespore compartment of sporulating cells under the control of sigmaG, as shown by Northern blot and primer extension analyses. The forespore-specific expression of B. subtilis sleB was further indicated by the forespore-specific accumulation of a SleB-green fluorescent protein fusion protein from which a putative secretion signal of SleB was deleted. Immunoelectron microscopy with anti-SleB antiserum and a colloidal gold-immunoglobulin G complex showed that the enzymes from both Bacillus species are located just inside the spore coat layer in the dormant spore, and in the dormant spore, the amidases appear exist in a mature form lacking a signal sequence. These results indicate that SleB is translocated across the forespore's inner membrane by a secretion signal peptide and is deposited in cortex layer synthesized between the forespore inner and outer membranes. The peripheral location of the spore-lytic enzymes in the dormant spore suggests that spore germination is initiated at the exterior of the cortex.

Amidohydrolases↗
PubMed1999

Development of Babesia gibsoni in the midgut of larval tick, Rhipicephalus sanguineus.

Studies were made on the development of Babesia gibsoni in the midgut of the larval tick, Rhipicephalus sanguineus. Six hr after repletion, merozoites of B. gibsoni, freed from erythrocytes, were observed in the midgut contents of the tick. After that, within 24 hr, those merozoites were transformed into the ring-forms which were relatively large, 2-3 microns in diameter. Later, the ring forms developed into the spherical forms which were subelliptical in shape and 4-6 microns in diameter. Within 2-4 days, the elongated forms, 5-8 microns in length, were found. At this time, some of the binucleated fusion form has assumed a form intermediate between the spherical and elongated-forms. About 5-6 days after repletion, large round or elliptic zygotes, 8-10 microns in diameter, were observed in the tick gut.

Animals↗
PubMed1999

Development of Babesia gibsoni in the midgut of the nymphal stage of the tick, Rhipicephalus sanguineus.

Studies were made on the development of Babesia gibsoni in the midgut of the nymphal stage of the tick, Rhipicephalus sanguineus. Six hr after repletion, merozoites of B. gibsoni, free of erythrocytes, were observed in the midgut contents of the ticks. After that, within 24 hr, those merozoites were transformed into ring-forms which were relatively large ring 1-2 microns in diameter. Later, the ring forms developed into spherical forms which were somewhat elliptical in shape and 3-4 microns in diameter. Within 2-4 days, bizarre forms (5-6 microns in diameter) developed into elongated forms (5-6 microns in length). About 5-6 days after repletion, large round or elliptic zygotes (7-9 microns in diameter) were observed in the ticks gut.

Animals↗
PubMed1999

Immunohistochemical evidence for an increased oxidative stress and carbonyl modification of proteins in diabetic glomerular lesions.

Advanced glycation end products (AGE) include a variety of protein adducts whose accumulation has been implicated in tissue damage associated with diabetic nephropathy (DN). It was recently demonstrated that among AGE, glycoxidation products, whose formation is closely linked to oxidation, such as carboxymethyllysine (CML) and pentosidine, accumulate in expanded mesangial matrix and nodular lesions in DN, in colocalization with malondialdehyde-lysine (MDA-lysine), a lipoxidation product, whereas pyrraline, another AGE structure whose deposition is rather independent from oxidative stress, was not found within diabetic glomeruli. Because CML, pentosidine, and MDA-lysine are all formed under oxidative stress by carbonyl amine chemistry between protein amino group and carbonyl compounds, their colocalization suggests a local oxidative stress and increased protein carbonyl modification in diabetic glomerular lesions. To address this hypothesis, human renal tissues from patients with DN or IgA nephropathy were examined with specific antibodies to characterize most, if not all, carbonyl modifications of proteins by autoxidation products of carbohydrates, lipids, and amino acids: CML (derived from carbohydrates, lipids, and amino acid), pentosidine (derived from carbohydrates), MDA-lysine (derived from lipids), 4-hydroxynonenal-protein adduct (derived from lipids), and acrolein-protein adduct (derived from lipids and amino acid). All of the protein adducts were identified in expanded mesangial matrix and nodular lesions in DN. In IgA nephropathy, another primary glomerular disease leading to end-stage renal failure, despite positive staining for MDA-lysine and 4-hydroxynonenal-protein adduct in the expanded mesangial area, CML, pentosidine, and acrolein-protein adduct immunoreactivities were only faint in glomeruli. These data suggest a broad derangement in nonenzymatic biochemistry in diabetic glomerular lesions, and implicate an increased local oxidative stress and carbonyl modification of proteins in diabetic glomerular tissue damage ("carbonyl stress").

Adult↗
PubMed1998

Synthesis of 13C-dehydrocoelenterazine and model studies on Symplectoteuthis squid bioluminescence.

In the photoprotein of an Okinawan squid bioluminescence of Symplectoteuthis oualaniensis L a dehydrocoelenterazine has been assigned as a chromophoric precursor to its apoprotein. To prove this mechanism, we have established new synthetic route to ca. 100%-13C incorporated dehydrocoelenterazine and coelenterazine at the neighboring carbon of the 2-position of 2,3-dihydroimidazo-[1,2a]-pyrazinone skeleton. This 13C enriched dehydrocoelenterazine readily converted in equilibrium between its adduct forms as a diastereomixture with glutathione (GSH) or dithiothreitol (DTT) compounds having sulfhydryl group. Structures of such adducts were fixed under acidic conditions and then discussed by NMR spectroscopy as well as absorbance and fluorescence spectra.

Animals↗
PubMed1998

Estrogen-dependent production of erythropoietin in uterus and its implication in uterine angiogenesis.

Although erythropoietin (Epo) has been shown to possess in vitro angiogenic activity, its physiological significance has not been demonstrated. Normally angiogenesis does not occur actively in adults but an exception is the female reproductive organ. In the uterine endometrium, angiogenesis takes place actively for supporting the endometrial growth that occurs during transition from the diestrus to estrous stage. This transition is under control of 17beta-estradiol (E2), an ovarian hormone, and can be mimicked by injection of E2 to ovariectomized (OVX) mouse. Thus, the uterus is a pertinent site to examine the Epo function in angiogenesis. We found that Epo protein and its mRNA were produced in an E2-dependent manner, when the uterus from OVX mouse was cultured in vitro. The de novo protein synthesis was not needed for E2 induction of Epo mRNA. Administration of E2 to OVX mouse induced a rapid and transient increase in Epo mRNA in the uterus. Injection of Epo into the OVX mouse uterine cavity promoted blood vessel formation in the endometrium. Furthermore, injection of the soluble Epo receptor capable of binding with Epo into the uterine cavity of non-OVX mouse in diestrus stage inhibited the endometrial transition to proestrus stage, whereas heat-inactivated soluble Epo receptor allowed the transition to occur. These results, combined with our finding that the endothelial cells in uterine endometrium express Epo receptor, strongly suggest that Epo is an important factor for the E2-dependent cyclical angiogenesis in uterus.

Animals↗
PubMed1998

Effects of cilostazol, an antiplatelet agent, on axonal regeneration following nerve injury in diabetic rats.

To evaluate the ability of cilostazol, an antiplatelet and vasodilating agent, to promote axonal regeneration in streptozotocin-induced diabetic rats, the time until beginning of regeneration (initial delay) and the axonal regeneration rate of the sciatic nerve were estimated using the pinch test, and ornithine decarboxylase activity was measured in dorsal root ganglia. At 5 weeks of diabetes, axonal regeneration rate remained unchanged but the initial delay was prolonged and ornithine decarboxylase induction was delayed in diabetic rats compared with those in normal rats. Cilostazol had little effect on these parameters in normal or diabetic rats. At 10 weeks of diabetes, diabetic rats showed both prolongation of initial delay and a decrease in axonal regeneration rate. Cilostazol markedly increased axonal regeneration rate in diabetic rats. Ornithine decarboxylase induction following nerve injury disappeared almost completely in diabetic rats but was maintained by cilostazol treatment. The effect of cilostazol in diabetic rats is thought to be mediated through its preventive effect on circulatory disorders. The active site of the drug appears to be early processes in nerve regeneration before ornithine decarboxylase induction. Further, the results suggest that the both axonal regeneration and this induction are sensitive to circulatory defects in diabetes.

Animals↗
PubMed1998

Accelerated formation of N epsilon-(carboxymethyl) lysine, an advanced glycation end product, by glyoxal and 3-deoxyglucosone in cultured rat sensory neurons.

The formation of advanced glycation end products (AGEs) is associated with pathophysiological changes with aging and disease processes. In the neurodegeneration in Alzheimer's disease and other neurodegenerative diseases. AGEs are speculated to play a role in their pathogenesis. We provide the first evidence for the induction of AGEs in cultured neuronal cells. Glyoxal and 3-deoxyglucosone (3-DG), AGE precursors, induced N epsilon-(carboxymethyl) lysine (CML), a well characterized and major AGE structure, in cultured rat sensory neurons in a time- and dose-dependent manner. CML formation was prevented by addition of aminoguanidine, an inhibitor of AGE formation. This culture system provides a useful model to analyze the role of the glycoxidation reaction in neuronal aging and neurodegenerative disorder.

Animals↗