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Biomedical subjects

Y Ueda

Publications and source records attributed to Y Ueda.

At least 613 records · Page 34Linked to original sources
PubMed1993

Prognostic implication of immunodetection of P glycoprotein in Ewing's sarcoma.

Increased expression of P glycoprotein is associated with multidrug resistance in many cell lines. P glycoprotein has been detected in different human tumors. To assess the implication of multidrug resistance in the prognosis of Ewing's sarcoma the expression of P glycoprotein was studied immunohistochemically in pre- and post-therapeutic tumor tissues of 21 cases treated according to the CESS 81 or 86 protocol. The response to chemotherapy was evaluated histologically. Formalin-fixed, paraffin-embedded and fresh frozen sections were immunostained with a monoclonal antibody to P glycoprotein, clone JSB 1, using the double APAAP method. P glycoprotein was detected in 12 cases of 21 (57%) in either pre- or postchemotherapy tumor tissues. From the 21 cases 8 revealed a good morphological response to chemotherapy (33%); 10 of the 13 non-responders were positive for P glycoprotein (77%), but only 2 of the 8 responders (25%). The difference was statistically significant (P < 0.05). Comparing P glycoprotein expression with the clinical outcome, we found that 7 of 12 positive cases had died (58%). From the negative cases only 3 of 9 had died (33%). However, judged by the Kaplan Meyer life tables, these data were not significant. In conclusion our results suggest that the immunodetection of P glycoprotein indicates a poor response to chemotherapy and probably a bad clinical outcome for Ewing's sarcoma patients.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Analysis of human and bovine milk lactoferrins by Rotofor and chromatofocusing.

1. Isoelectric points of human and bovine lactoferrins were evaluated by Rotofor and chromatofocusing analysis. 2. By Rotofor, the isoelectric value of human lactoferrin fraction was determined at 8.7 and that of bovine lactoferrin at 8.8. 3. By chromatofocusing analysis, human and bovine lactoferrins showed different elution patterns. Human lactoferrin was eluted at pH 6.8-8 and bovine lactoferrin eluted at pH 8.2-8.9.

Animals↗
PubMed1993

Different expression of modified low density lipoprotein receptors in rabbit peritoneal macrophages and Kupffer cells.

We have previously reported that mouse peritoneal macrophages have three types of modified low density lipoprotein (LDL) receptors. One is specific for acetylated LDL (Ac-LDL), the second is for oxidized LDL (Ox-LDL), and the third recognizes both (Arai, H. et al. (1989) Biochem. Biophys. Res. Commun. 159, 1375-1382). In the current study, the characteristics of modified LDL receptors in rabbit peritoneal macrophages and Kupffer cells from rabbits were investigated. Cross-competition studies of the degradation assay between Ox-LDL and Ac-LDL in rabbit peritoneal macrophages showed that the degradation of 125I-labeled Ox-LDL was almost completely inhibited by an excess amount of unlabeled Ac-LDL. On the other hand, an excess amount of unlabeled Ox-LDL suppressed 125I-labeled Ac-LDL degradation only partially. In contrast, in Kupffer cells an excess amount of unlabeled Ox-LDL inhibited the degradation of 125I-labeled Ac-LDL almost completely, whereas the degradation of 125I-labeled Ox-LDL was inhibited only partially by Ac-LDL. Scatchard analysis of binding assay showed that rabbit peritoneal macrophages have a single class of receptor for Ox-LDL, which binds maximally 0.31 microgram/mg cellular protein (Bmax) with an apparent dissociation constant (Kd) of 19.3 micrograms/ml, and two classes of receptors for Ac-LDL; one with high affinity (Bmax 0.025 microgram/mg cellular protein, Kd 0.040 micrograms/ml) and the other with low affinity (Bmax 0.08 microgram/mg cellular protein, Kd 11.31 micrograms/ml). On the other hand, Kupffer cells have two classes for Ox-LDL; one is a high affinity receptor (Bmax 0.53 microgram/mg cellular protein, Kd 0.99 microgram/ml) and the other is a low affinity receptor (Bmax 3.71 micrograms/mg cellular protein, Kd 16.2 micrograms/ml) and a single class for Ac-LDL (Bmax 0.60 microgram/mg cellular protein, Kd 7.24 micrograms/ml). These results indicate that rabbit peritoneal macrophages have two kinds of modified LDL receptors; one is specific for Ac-LDL, and the other recognizes both Ox-LDL and Ac-LDL.

Acetylation↗
PubMed1993

Polyurethane surface modification by graft polymerization of acrylamide for reduced protein adsorption and platelet adhesion.

Surface modification of polyurethane by glow-discharge treatment and subsequent graft polymerization of acrylamide was studied. The modified hydrophilic surfaces were characterized by the measurements of dynamic contact angle and zeta potentials and examined for protein adsorption behaviour and platelet adhesion. Data from in vitro and ex vivo experiments indicated a reduction of protein adsorption and platelet adhesion for the hydrophillic graft polymers, the extent of which was correlated to polymer graft density.

Acrylamides↗
PubMed1993

Characterization of pro-opiomelanocortin processing in heterologous neuronal cells that express PC2 mRNA.

We have investigated processing of monkey pro-opiomelanocortin (POMC) following transfection into heterologous neuronal Neuro 2A (N2A) cells. In several separately transfected stable cell lines (termed N2A/POMC2-like; n = 4), POMC was processed to beta E only, by direct cleavage from the precursor. Thus, these cell lines did not produce beta E in the orderly manner observed in the pituitary, that is, via the intermediate peptide beta LPH. Analysis of one representative N2A/POMC2 cell line revealed that the extent of processing to beta E appeared to be negatively correlated with precursor expression level, suggesting that the processing enzyme(s) in these cells was present in limiting amounts. Northern analysis of PC1 and PC2, two recently cloned processing enzymes, showed that N2A/POMC2 cells expressed low levels of PC2 mRNA, but no detectable PC1 mRNA. These data suggest that (1) the order of processing observed in the pituitary is not exclusively determined by tertiary folding of the precursor, but rather by the complement of processing enzymes in a particular cell, and (2) if PC2 is responsible for POMC processing in N2A/POMC2 cells, this enzyme, expressed in limiting amounts, appeared to show selectivity for the beta E amino terminal processing site.

Animals↗
PubMed1993

Expression of muscarinic and nicotinic receptor mRNA in the salivary gland of rats: a study by in situ hybridization histochemistry.

Expression of muscarinic receptor mRNA subtypes (m1-5) and nicotinic receptor subunits (alpha 2-4, and beta 2) was examined in the rat submandibular gland by in situ hybridization histochemistry, using oligonucleotide probes for the muscarinic receptor and RNA probes for the nicotinic receptors. m2, alpha 3, and beta 2 mRNA were strongly expressed in the submandibular ganglion, and m3, alpha 2, alpha 3, alpha 4, and beta 2 were expressed in the striated and interlobular duct cells. Both muscarinic and nicotinic receptors were coexpressed in the same ganglion neurons, while none of these mRNA were detected in the terminal secretory units.

Animals↗
PubMed1993

Immunoglobulin G that interferes with thyroid-stimulating antibody measurements can be eliminated specifically by incubation with synthetic peptides corresponding to partial sequences of the human thyrotropin receptor.

Two IgG preparations out of more than 100 tested, distinct from the typical Graves' disease IgG, were shown specifically to enhance the cAMP production of FRTL-5 cells by the addition of a synthetic peptide, P-218, corresponding to the partial amino acid sequence from No. 354 to 367 of the h thyroid-stimulating hormone (TSH) receptor. IgG obtained from a patient with Graves' disease revealed a serial alteration of the enhancement; negative in July, 1989, potent in January, 1991, and weak in September 1991. During this time there was no remarkable change in the patient's serum protein components or TSH receptor antibody activities. A peptide with a completely reverse sequence of P-218 showed little effect, and P-218 in combination with bTSH or forskolin did not affect cAMP production by these ligands, and did not alter the inhibitory activity of thyroid-stimulation-blocking antibody. High concentrations of P-218 resulted in reduction of such enhancing effects of cAMP by thyroid-stimulating antibody. P-218 affinity chromatography showed almost complete absorption and recovery of thyroid-stimulating antibody and P-218 reactivity. In the 15 synthesized peptides with proximal sequences of P-218 (from 338 to 378), regions thought to be involved with the enhancement were defined as follows: 354-367 (P-218) is a critical unit; 354-357 and 364-367 are considered to be the essential sites; several amino acid extensions on both N- and C-terminal sides of P-218 show additional enhancement. In conclusion, evidence was shown to indicate the presence of IgG that interferes with thyroid-stimulating antibody measurements.

Amino Acid Sequence↗
PubMed1993

Effect of cerebral venous congestion on the pressure-volume index in the evaluation of intracranial pressure dynamics.

Translocation of cerebrospinal fluid (CSF) between the intracranial and spinal subarachnoid space was blocked by ligating the cervical spinal core in eight cats under pentobarbital and nitrous oxide anesthesia, and the effects of cerebral venous congestion on the pressure-volume index (PVI), a measure relating the change in intracranial volume, and the logarithm of intracranial pressure (ICP) were evaluated. The changes in the volume-pressure response (VPR), a measure of intracranial elastance, were calculated simultaneously. Cerebral venous congestion was induced by lowering the head relative to the level of the heart by tilting the trunk of the animals to 20 degrees below horizontal. The presence of venous congestion was confirmed by an increase in the sagittal sinus pressure (SSP). The body position was shifted from horizontal prone (H1 group) to head-down tilt (D1 group) in four animals (group 1) and from head-down tilt (D2 group) to horizontal prone (H2 group) in the other four animals (group 2), and PVI and VPR were determined in each group. The changes in ICP and SSP with change of body position in group 1 were not significantly different from those in group 2, with both pressures changing by 7-8 mm Hg. PVI showed no significant differences between the H1 group and H2 group or between the D1 group and D2 group. The mean (+/- SEM) PVI for all measurements in the head-down tilt position (D1 and D2 groups) was significantly higher (0.50 +/- 0.02 ml; p < 0.01) than in the horizontal position (H1 and H2 groups; 0.35 +/- 0.02 ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Extracellular neuroactive amino acids in the rat striatum during ischaemia: comparison between penumbral conditions and ischaemia with sustained anoxic depolarisation.

Changes in the extracellular levels of excitatory and inhibitory amino acid transmitters were studied in the rat striatum during penumbral ischaemia using intracerebral microdialysis. Effects of penumbral forebrain ischaemia were compared with those of ischaemia with sustained anoxic depolarisation and K+ (100 mM). Comparisons were also made between different groups of animals at 2 and 24 h after dialysis probe implantation. The K+ stimulus did not provoke any release of excitatory amino acids in the 24-h group, probably reflecting a decrease of functional synapses adjacent to the probe. During 30 min of penumbral ischaemia, excitatory amino acids did not reach critical concentrations in the extracellular fluid, and increases in levels of inhibitory/modulatory amino acids were similar. On the other hand, severe transient ischaemia resulted in massive synchronous release of many neuroactive excitatory and inhibitory compounds, in both the 2- and 24-h groups. These and other data suggest that changes during severe ischaemia may arise from both neurotransmitter and metabolic pools. It is concluded that ischaemic damage in the penumbra may not be related to extracellular neuroactive amino acid changes generated within this region.

Alanine↗
PubMed1993

Replacement of chordae tendineae using expanded polytetrafluoroethylene (ePTFE) sutures during mitral valve replacement in patients with severe mitral stenosis.

Since September 1991, 20 patients with mitral stenosis underwent mitral valve replacement and chordal replacement with expanded polytetrafluoroethylene (ePTFE) sutures. The continuity between the papillary muscles and the mitral annulus was maintained by four mattress sutures of ePTFE, which connected the stumps of the papillary muscle heads to the mitral annulus at the 2, 4, 8, and 10 o'clock positions. Low profile bileaflet prosthetic valves were inserted. There was no mortality either in-hospital or during follow-up. There was no valve related morbidity, such as valve structural failure, thromboembolism, anticoagulant related hemorrhage, prosthetic valve endocarditis, or posterior left ventricular rupture. The technique of replacing chordae tendineae is described in detail.

Chordae Tendineae↗
PubMed1993

Neuropathological studies of the spinal cord in early stage HTLV-I-associated myelopathy (HAM).

Necropsy findings for a patient with HTLV-I-associated myelopathy (HAM) of 9 months clinical duration are reported. Loss of myelin sheaths and axons together with perivascular lymphocytic infiltration was seen in the lateral and posterior columns of the spinal cord from the cervical to the lumbar region where vacuolar changes caused by the splitting of myelin sheaths were prominent. Immunohistochemical analyses revealed CD8+ cytotoxic T cell infiltration predominated in the absence of HTLV-I core protein antigen bearing-cells in the brain and spinal cord. Myelin sheath damage and predominant CD8+ cytotoxic T cell infiltration are thought to be the main neuropathological findings in the spinal cord in early stage HAM.

Aged↗
PubMed1993

Tissue-specific and substrate-specific endoproteolytic cleavage of monkey pro-opiomelanocortin in heterologous endocrine cells: processing at Lys-Lys dibasic pairs.

This study compares the processing of pro-opiomelanocortin (POMC) at two Lys-Lys cleavage sites, located in the carboxy-terminal domain of the precursor, one site marking the amino terminus of beta-melanocyte-stimulating hormone (beta-MSH) and the other in the carboxy-terminus of beta-endorphin (beta E). These comparisons were carried out by transfecting monkey POMC cDNA into two heterologous cell lines: AtT-20, which endogenously expresses mouse POMC, and Rin m5F, which has been previously used as a host for transfected POMC. These cells lines are known to process POMC differently at Lys-Arg residues, though less is known about their Lys-Lys cleavage. Our results have demonstrated both tissue-specific and site-specific factors controlling Lys-Lys cleavage. The AtT-20 line appears not to perform either Lys-Lys cleavage. Rin m5F cells, on the other hand, fail to process the site at the carboxy terminus of beta E (beta E28-29) but do process, to a significant extent, the N-terminal site to beta-MSH. That this differential processing is unlikely to be due to a POMC conformation which would make the beta E site inaccessible was demonstrated by mutating the sites from Lys-Lys to Lys-Arg. With such mutants, Rin m5F cells fully processed at both locations. Interestingly, the mutant Lys-Arg sites were not fully processed by AtT-20 cells. These results are discussed in terms of the complement of processing enzymes expressed in each of the cell lines, as well as the role of residues surrounding the diabasic cleavage sites in determining the likelihood of proteolysis.

APUD Cells↗
PubMed1993

Axial length of eyes with rhegmatogenous retinal detachment.

We conducted a prospective study of 226 eyes with nontraumatic rhegmatogenous retinal detachment; we examined patient characteristics as well as changes in axial length and corneal curvature induced by scleral buckling surgery. Eyes with a round hole in lattice degeneration were characterized by axial length that was longer than that of eyes with retinal tears with and without lattice degeneration. Sex and age also correlated significantly with axial length. Surgically induced changes in axial length depended upon the procedures performed, but the retinal detachment surgery primarily caused a change in the refractive status.

Adult↗
PubMed1993

[Studies on the treatment of chronic hepatitis C with interferon. Assessment of treatment regimens and response to treatment].

The difference in response rate to interferon (IFN) among several treatment regimens was assessed retrospectively in 48 HCV-RNA positive patients with chronic hepatitis C. The study focused on patients' pretreatment profiles and response to treatment, histological findings before and after the treatment and the significance of HCV-RNA detection in evaluating the outcome. A complete response (CR) evaluated by the outcome of alanine aminotransferase (ALT) was obtained in 16 of 25 patients (64.0%) treated with IFN in doses of 3 to 6 million units daily for the first 4 or 8 wks and subsequent dosing twice or three times weekly for the following 8 to 146 wks. In contrast, CR was obtained in only 7 of 16 patients (43.8%) treated with the regimen in which patients received IFN in doses of 1 to 6 million units daily for 4 to 8 wks and no subsequent IFN. In comparing the responders to IFN (25 cases) and the non responders (19 cases), there were no significant differences regarding patients' age, sex, the presence or absence of history of blood transfusion, pretreatment ALT values or histological magnitude, or total doses of IFN administered. When the basal and final biopsy samples were compared, Knodell's index of histological activity had decreased significantly in the responders but not in the non responders. In 24 of the 25 responders, HCV-RNA had disappeared from their serum at the end of treatment, and in 23 it remained undetectable 6 months after treatment. In contrast, in 6 of the 19 non responders HCV-RNA had become negative at the end of treatment but was detectable in all cases 6 months after treatment. Thus, it is concluded that (1) a regimen of daily administration for the first 4 or 8 wks with subsequent dosing twice or three times weekly was preferable in terms of obtaining frequent CR, (2) response to IFN cannot be predicted by a patient's pretreatment profile, (3) in responders, histological activity decreases, and (4) in responders, HCV-RNA becomes undetectable not only at the end of treatment but also 6 months after treatment.

Adult↗