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Biomedical subjects

T Yasuda

Publications and source records attributed to T Yasuda.

At least 289 records · Page 16Linked to original sources
PubMed1997

Evaluation of the prognosis of cancer patients with metastatic bone tumors based on serial bone scintigrams.

We counted the lesions at the time of detection of bone metastases and calculated the rate of increase in the number of bone metastases from changes in serial bone scintigrams, and investigated the usefulness of serial scintigrams as a prognostic indicator in patients with metastatic bone tumors. Subjects were 112 patients with bone metastases from four types of primary lesion: 21 with prostate cancer, 27 breast cancer, 39 lung cancer and 25 stomach cancer. Of these, 18 (prostate), 19 (breast), nine (lung) and eight (stomach) underwent serial bone scintigrams in which bone metastases were first detected and identified as progressing. The numbers of lesions at the time of detection of bone metastases for prostate and stomach cancers were significantly greater than those for lung cancer. The rate of increase in the number of bone metastases for stomach cancer was significantly higher than that for prostate or breast cancers. There was no correlation between the survival time after the detection of bone metastases and the number of lesions at the time of detection in the four types of cancer. However, in prostate cancer, a negative correlation existed between the survival time after the detection of bone metastases and the rate of increase in the number of bone metastases. Thus, in patients with bone metastases from prostate cancer, it appears that the rate of increase in the number of bone metastases, estimated from serial bone scintigrams, was indicative of prognosis.

Adult↗
PubMed1997

Intravascular ultrasonic evidence by constant cross-sectional area of atherosclerotic plaques during coronary vasomotion in humans.

AIMS: This study aims to visualize ultrasonically deformation of atherosclerotic plaques in human coronary arteries during vasoconstriction and vasodilatation. METHODS AND RESULTS: Intravascular ultrasound detected occult atherosclerosis in angiographically normal coronary arteries of eight patients with chest pain at rest. During the acetylcholine provocative test, intravascular ultrasound monitored deformation of the atherosclerotic plaques. At the last step of the test, intracoronary injection of isosorbide dinitrate caused vasodilation. Under control, acetylcholine-treated, and isosorbide dinitrate-treated conditions, cross-sectional areas of sonolucent circle and vessel lumen were measured. Subtraction of the latter from the former gave the area of atherosclerotic plaque. In the process of vasoconstriction and vasodilation, the plaque area did not change significantly. CONCLUSION: The cross-sectional area of the atherosclerotic plaque appeared to be constant during vasomotion of human coronary arteries.

Acetylcholine↗
PubMed1997

Hypoparathyroidism and pseudohypoparathyroidism.

Hypoparathyroidism is a clinical disorder characterized by hypocalcemia and hyperphosphatemia in the absence of renal failure and hypomagnesemia. The causes of hypoparathyroidism can be classified as two groups: (i) insufficient parathyroid hormone (PTH) secretion in relation to the serum calcium level (hypoparathyroidism); and (ii) impaired PTH action (pseudohypoparathyroidism). The main emphasis in this report is to distinguish subgroups based on the etiology and pathophysiology of the various aspects of the disease.

Diagnosis, Differential↗
PubMed1997

Regulation of gelatinase production and invasiveness by organ-specific fibroblasts in high- and low-metastatic clones from murine RCT sarcoma.

Regulation of gelatinase production, invasiveness and migration activity by organ-specific fibroblasts from embryo, subcutaneous and lung tissues of mice were investigated in high-metastatic RCT+ and low-metastatic RCT- clones established from a poorly differentiated murine sarcoma. In the conditioned media of RCT+ cells, mouse skin fibroblasts (MSF) obtained from the tissue of tumor origin (orthotopic) stimulated the production of the 105-kD gelatinase more than C3H/ 10T1/2 clone 8 (C3H/10 T1/2 CL8) or mouse lung fibroblasts (MLF). In the conditioned media of RCT- cells, however, cocultivation with fibroblasts showed only slight stimulatory effects on the production of the 105-kD gelatinase. In the invasion assay, using a reconstituted basement membrane (matrigel), RCT+ cells cocultivated with MSF showed significantly higher invasiveness than those cocultivated with C3H/10T1/2 CL8 or MLF. However, no significant differences were shown in the invasiveness of RCT- cells in cocultivation with three types of fibroblasts and in cultivation without fibroblasts. There was no significant difference in migration activity between RCT+ and RCT- cells cultivated alone. But in the cocultivation of both clones with MSF, the migration activity of RCT+ cells was significantly higher than that of RCT- cells. These findings suggest that MSF might delineate the difference in characteristics related to the metastatic potential of RCT+ and RCT- cells through regulation by organ-specific factors.

Animals↗
PubMed1997

Comparison of bactericidal effects of commonly used antiseptics against pathogens causing nosocomial infections. Part 2.

Opportunistic infections caused by gram-negative rods (GNR), conventionally regarded as organisms with low or no pathogenicity, and intractable infections caused by various resistant organisms pose a great problem now. In view of this, we determined the bactericidal effects of 5 commonly used disinfectants using as the test strains Xanthomonas maltophilia and Serratia marcescens, chosen among other GNR since they often cause nosocomial infections. Regarding the bactericidal activities against X. maltophilia and S. marcescens, both sensitive strains and resistant strains were killed within 20 s of exposure to povidone-iodine and sodium hypochlorite. With chlorhexidine, 1 strain each of both species was not killed within 10 min of exposure at a concentration of 0.2%. Both sensitive strains and resistant strains of X. maltophilia were killed within 20 s of exposure to benzalkonium at 0.02%, while a concentration of 0.1% was required for benzalkonium to kill S. marcescens within 20 s. With Tego-51, both sensitive strains and resistant strains of X. maltophilia were killed within 20 s at 0.02%, while 1 strain of S. marcescens was not killed within 20 s at a concentration of 0.1%. In the use of disinfectants, comparative bactericidal effects of various disinfectants against clinical isolates should be taken into consideration.

Anti-Infective Agents, Local↗
PubMed1997

Cloning and characterization of the promoter regions of the human parathyroid hormone (PTH)/PTH-related peptide receptor gene: analysis of deoxyribonucleic acid from normal subjects and patients with pseudohypoparathyroidism type 1b.

Expression of the PTH/PTH-related peptide (PTHrP) receptor (PTHR) in the mouse is controlled by at least two promoters. The downstream promoter (P2) is ubiquitously expressed, whereas expression of the upstream promoter (P1) is largely restricted to kidney. These observations may provide a genetic basis for a human PTH resistance syndrome, pseudohypoparathyroidism type 1b (PHP1b), in which renal, but not osseous, signaling by PTH is defective. We, therefore, cloned and characterized the 5'-end of the human PTHR gene and found that its organization is very similar to that of the mouse. Transcription initiation sites of human P1 and P2 promoters are in similar, but not identical, positions to those of the mouse gene. The identification of a human P2 promoter is significant because no P2-specific human PTHR complementary DNAs have been isolated to date. Southern analysis of genomic DNA from seven PHP1b patients did not reveal any rearrangements in proximal promoter regions or exons encoding 5'-untranslated region sequences. No significant sequence differences were found in clones of normal and patient DNAs encompassing proximal promoter sequences, and untranslated region and signal sequence exons. Thus, in the seven PHP1b patients analyzed, no defects were identified that would influence initiation site selection, stability, or splicing of renal PTHR transcripts. These data indicate that the genetic defect(s) in PHP1b in these patients lies in distal enhancer elements of the gene, in an essential transcriptional regulator, or in some as yet unidentified cofactor required for renal PTH signaling.

Adolescent↗
PubMed1997

Axonal pathology in Japanese Guillain-Barré syndrome: a study of 15 autopsied cases.

We assessed the frequency and extent of axonal involvement in the ventral spinal roots in 15 Japanese autopsied patients with Guillain-Barré syndrome (GBS). Teased-fiber preparation revealed that five had predominantly axonal pathology with minimal segmental demyelination, seven had predominantly segmental demyelination with minimal axonal changes, two patients showed a mixture of both conditions, and one patient did not show any particular pathologic changes. We confirmed axon loss by immunohistochemical analysis of high-molecular-weight neurofilament protein. Macrophage invasion was a prominent feature in nerves with predominantly axonal changes. Two patients with severe axonal involvement and prolonged clinical courses exhibited motor neuron loss with astrogliosis in the ventral horns. These results suggest that autopsy-verified axonal involvement is more frequent among Japanese GBS patients than in Caucasian populations but less frequent than that reported from northern China.

Adult↗
PubMed1997

Valinomycin induces apoptosis of ascites hepatoma cells (AH-130) in relation to mitochondrial membrane potential.

Valinomycin is a potassium ionophore, and is well known to cause the collapse of the mitochondrial membrane potential. It has been reported that loss of mitochondrial membrane potential is observed in the early stages of apoptosis induced by various agents. Thus, the effects of valinomycin on tumor cells were examined. Valinomycin induced uncoupling of respiration and depolarization of isolated mitochondria. Depolarization of intact mitochondria in AH-130 rat ascites hepatoma cells was also induced by valinomycin. Valinomycin induced apoptosis revealing the typical apoptotic characteristics such as fragmentation and ladder formation of DNA, shrinkage of cells, and formation of pycnotic nucleus. There was a correlation between the depolarization of mitochondria and DNA fragmentation. After depolarization of mitochondria, the activity of caspase-3-like protease but not caspase-1-like protease increased markedly. In contrast, this apoptosis did not involve the release of reactive oxygen species from mitochondria, increase in intracellular calcium concentration, or protein synthesis. In addition, anti-apoptotic members of the Bcl-2 family (Bcl-xL and Bcl-2) were not correlated with apoptosis. These results indicate that valinomycin might induce apoptosis through degradation of the mitochondrial membrane potential. Taken together, these observations suggest that there may be a mechanism that transmits the signal from mitochondrial depolarization to subsequent apoptosis execution steps.

Animals↗
PubMed1997

Generation of basidiomycetous hyphal cell-aggregates by addition of the Arg-Gly-Asp motif-containing fragment of high-molecular-weight cell-adhesion protein MFBA derived from the basidiomycete Lentinus edodes.

The Arg-Gly-Asp (RGD) motif-containing fragment of high-molecular-weight cell-adhesion protein MFBA derived from Lentinus edodes caused a significant aggregation of the fragmented hyphal cells of Schizophyllum commune. This fungal cell-aggregation was inhibited by a previous treatment of the cells with the Gly-Arg-Gly-Asp-Ser-Pro peptide, but not with the Gly-Arg-Gly-Glu-Ser-Pro peptide, showing that the RGD motif is essential for the cell-aggregation activity.

Basidiomycota↗
PubMed1997

Application of liposomes for development of oral vaccines: study of in vitro stability of liposomes and antibody response to antigen associated with liposomes after oral immunization.

In order to evaluate the usefulness of liposomes as oral vaccines, the stability of liposomes and serum IgA antibody response to antigen associated with liposomes after oral administration were examined. Liposomes composed of dipalmitoylphosphatidylcholine (DPPC), dipalmitoylphosphatidylserine (DPPS), and cholesterol (Chol) (1:1:2, molar ratio), distearoylphosphatidylcholine (DSPC) and Chol (7:2, molar ratio), and DSPC, DPPS, and Chol (7:3:2 or 1:1:2, molar ratio) were stable in acidic solution (pH 2.0), bile, and pancreatin solution, whereas liposomes composed of DPPC and Chol (7:2, molar ratio) and DPPC, DPPS, and Chol (7:3:2, molar ratio) were unstable in pH 2.0 and/or bile solutions. After the oral immunization of antigen (ganglioside GM1)-containing liposomes composed of DPPC, DPPS, and Chol (1:1:2, molar ratio) to mice, the serum IgA antibody responses against ganglioside GM1 were found. Furthermore, when monophosphoryl lipid A was incorporated into liposomes containing ganglioside GM1, further augmentation of IgA responses to ganglioside GM1 was observed. On the other hand, the oral administration with liposomes composed of DPPC, Chol, and ganglioside GM1 (unstable liposomes), ganglioside GM1 mixed with liposomes composed of DPPC, DPPS and Chol, and ganglioside GM1 alone was unable to induce any detectable anti-ganglioside GM1 IgA antibody responses. These results suggest that liposomes which showed the stability to acidic solution, bile, and pancreatin solution would serve effectively as an oral delivery vehicle for inducing mucosal immune responses.

Administration, Oral↗
PubMed1997

Evaluation of cationic liposomes for delivery of diphtheria toxin A-chain gene to cells infected with bovine leukemia virus.

We investigated whether cationic liposomes are efficient at delivering the gene for diphtheria toxin A-chain (DT-A) under the control of the long terminal repeat (LTR) of bovine leukemia virus (BLV) (pLTR-DT) into BLV-infected cells and are also suitable for in vivo use. The transfection activity of the cationic liposomes composed of N-(alpha-trimethylammonioacetyl)-didodecyl-D-glutamate chloride (TMAG), dioleoyl phosphatidylethanolamine (DOPE) and dilauroyl phosphatidylcholine (DLPC) (1:2:2, molar ratio) (TMAG-liposome) and liposomes composed of phosphatidylserine (PS) (PS-liposome) was evaluated by the luciferase assay using a plasmid which contains the coding sequence of firefly luciferase under the control of the SR alpha promoter (pSR alpha/L-A delta 5). The TMAG-liposome gave highly efficient transfection in the presence of serum. On the other hand, PS-liposome showed inferior efficiency. When BLV-infected cells were co-transfected with a fixed amount of pSR alpha/L-A delta 5-entrapped TMAG-liposome and various amount of pLTR-DT-containing TMAG-liposome, the luciferase activity in the BLV-infected cells was inhibited by the addition of pLTR-DT-entrapped TMAG-liposome dose-dependently. The cationic TMAG-liposome containing pLTR-DT was successively added to BLV-infected cells in culture. The number of viable cells was markedly reduced by the cationic TMAG-liposome containing pLTR-DT. On the other hand, TMAG-liposome containing pSR alpha/L-A delta 5 showed no such effect. pLTR-DT entrapped by the cationic TMAG-liposome was not digested by the treatment with DNase I and with serum. These results suggest that the cationic liposomes, such as TMAG-liposome, may be efficient transfection reagent for the BLV-infected cells and can be utilized for DT-A gene delivery into the BLV-infected cells in vivo.

Animals↗
PubMed1997

Prevalence and allele frequency estimation of bovine leukocyte adhesion deficiency (BLAD) in Holstein-Friesian cattle in Japan.

Blood samples from 796 Holstein dairy cows in 20 herds from 6 districts in Japan from June 1994 to August 1995 were examined to determine whether they were BLAD-free, BLAD carriers, or BLAD-affected by use of DNA-polymerase chain reaction (PCR) analysis. The usage of semen of confirmed BLAD-carriers for artificial insemination in the Hokkaido district and two selected dairy farms was examined to estimate the gene frequency of BLAD carriers of sires. BLAD-carrier prevalence in 20 herds (796 cows, over 2.5 years old) ranged from 0 to 23.5%, and the mean BLAD-carrier prevalence was 8.1%. The BLAD-carrier prevalence in 10 herds (363 cows) in which the occurrence of BLAD was not detected by the DNA-PCR test ranged from 0 to 12.5% with a mean of 5.4%. The BLAD-carrier prevalence in 10 herds (433 cows) in which the occurrence of BLAD was confirmed by DNA-PCR analysis ranged from 2.6 to 23.5% with a mean of 10.8%, and these values were significantly (P < 0.05) higher than those of dairy herds in which the occurrence of BLAD was not detected. The age distribution in BLAD carriers in these cows ranged from 2.5 to 11 years. The mean gene frequencies of BLAD among 796 cows from 20 herds and 433 cows from 10 herds in which the occurrence of BLAD was detected were 0.041 and 0.054, respectively. The proportional usage of semen of BLAD carriers for artificial insemination in the Hokkaido district in 1992 was 12.6%, and its gene frequency was 0.058. On two selected farms in which higher BLAD-carrier rates were detected, the prevalences were 35.5% and 25.8%, and their gene frequencies were 0.177 and 0.129, respectively. The occurrence of BLAD-affected in Holstein dairy cattle was estimated to be 0.16-0.31% at birth in Japan without genetic control.

Age Factors↗
PubMed1997

In vivo antitumor effect of cationic liposomes containing diphtheria toxin A-chain gene on cells infected with bovine leukemia virus.

A plasmid pLTR-DT which contained a gene for diphtheria toxin A-chain (DT-A) under the control of the long terminal repeat (LTR) of bovine leukemia virus (BLV) (BLV-LTR) in the multicloning site of pUC-18 was entrapped in cationic liposomes composed of N-(alpha-trimethylammonioacetyl)-didodecyl-D-glutamate chloride (TMAG), dioleoyl phosphatidylethanolamine (DOPE) and dilauroyl phosphatidylcholine (DLPC) (1:2:2, molar ratio) (TMAG-liposome), and their antitumor effect on BLV-infected tumor cells was examined in vivo. The cationic TMAG-liposome containing pLTR-DT was successively injected into the tumor transplanted to nude mice. The growth of tumor was significantly inhibited by the injection of cationic TMAG-liposome containing pLTR-DT. On the other hand, TMAG-liposome containing pUC18 plasmids showed no such effect. These results suggest that a DT-A expression plasmid under the control of BLV-LTR is highly toxic to the BLV-infected tumor cells, and that the cationic liposomes, such as TMAG-liposome, may be efficient transfection reagent for BLV-infected tumor cells and can be utilized for DT-A gene delivery into BLV-infected tumor cells in vivo.

Animals↗
PubMed1997

Jansen-type metaphyseal chondrodysplasia: analysis of PTH/PTH-related protein receptor messenger RNA by the reverse transcriptase-polymerase chain method.

Jansen-type metaphyseal chondrodysplasia (JMC) has both delayed ossification in long bones and usually hypercalcemia. We report a Japanese male patient with JMC who presented with rachitic signs on radiographs, hypercalcemia (13 mg/dl) and low %TRP at age 3 months (mo). Hypercalcemia was treated from age 3 mo to 11 yr. Progressive widening, splaying and fragmentation of the metaphyses have been recognized on radiographs which resulted in shortened tubular bones and consequent short stature [107 cm (-6.5 SD)] at age 13 yr. Hypercalcemia tended to normalize, and %TRP became normal at age 13 yr. Repeated measurements of serum PTH and PTH-related protein (PTHrP) levels showed that they were low or normal in the face of hypercalcemia and high urine cAMP excretion, which led us to suspect constitutive activation of the PTH/PTHrP receptor. Direct sequencing of PTH/PTHrP receptor complementary DNA from skin fibroblast cells revealed a CAC to CGC transversion yielding a strictly conserved His223 to Arg substitution found in 90% of DNA fragment in the second transmembrane domain of the receptor. This mutation created a restriction site Sphl (G/CATG/C). Direct sequencing of genomic DNA and also restriction enzyme digestion revealed heterozygous transition. The mutation was absent in the parents with normal phenotype. We conclude that both dysplastic bone lesions and calcium homeostasis are age-dependent in JMC, and that the His223-Arg substitution is the same as that found in four Caucasian patients with a similar phenotype irrespective of the ethnic difference, and that the preferential expression of an abnormal allele of the PTH/PTHrP receptor mRNA in skin fibroblast despite heterogygotic transversion in the genomic DNA suggests the importance of allele expression.

Dwarfism↗
PubMed1997

Gene transfection by cationic liposomes: comparison of the transfection efficiency of liposomes prepared from various positively charged lipids.

We compared the transfection efficiency of four types of positively charged liposomes composed of (i) N-(alpha-trimethylammonioacetyl)-didodecyl-D-glutamate chloride (TMAG), dilauroylphosphatidylcholine (DLPC), and dioleoylphosphatidylethanolamine (DOPE) (1:2:2 molar ratio); (ii) 3 beta [N-(N', N'-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol) and DOPE (3:2 molar ratio); (iii) dimethyldioctadecylammonium bromide (DDAB) and DOPE (1:2.2 molar ratio); (iv) N-[1-(2,3-dioleyloxy) propyl]-N,N,N-trimethylammonium chloride (DOTMA) and DOPE (1:1, w/w; lipofectin). Luciferase gene was used as a reporter gene. Among the cationic lipsomes used, the liposomes composed of TMAG, DOPE and DLPC showed a much higher efficiency of plasmid DNA entrapment than the other cationic liposomes tested. In the absence of serum, the cationic multilamellar vesicles (MLV) and small unilamellar vesicles (SUV) composed of TMAG, DOPE and DLPC gave highly efficient transfection. On the other hand, MLV, dehydration-rehydration vesicles (DRV), and SUV liposomes prepared with the mixtures of DC-Chol and DOPE showed similar levels of transfection efficiency. However, the cationic liposomes composed of DDAB and DOPE showed inferior efficiency, whether in the form of DRV, SUV or MLV. The transfection efficiency of lipofectin was also low. In the presence of serum, on the other hand, a considerable (about 30-50%) amount of transfection activity was still observed at 10% fetal calf serum in the cationic MLV and SUV composed of TMAG, DOPE and DLPC. Cationic MLV, composed of TMAG, DOPE and DLPC, Cationic MLV, composed of TMAG, DOPE and DLPC, can transfect plasmid DNA, not only in the adherent cell lines but also, in the suspension cell lines. These findings indicate that the transfection efficiency of cationic liposomes is affected by the lipid composition, the type of liposome, or the presence or absence of serum. They also indicate that the cationic liposomes containing TMAG, DOPE and DLPC are efficient vectors for gene transfer into cells.

Animals↗
PubMed1997

Molecular mechanisms of apoptosis in HL-60 cells induced by a nitric oxide-releasing compound.

Nitric oxide (NO) generated from 1-hydroxy-2-oxo-3, 3-bis(2-aminoethyl)-1-triazene (NOC 18), an NO-releasing compound, induced monocytic differentiation of human promyelocytic leukemia HL-60 cells as assessed by expression of nonspecific esterases and morphologic maturation. Simultaneously, DNA fragmentation and morphological alterations typical of apoptosis were also induced. To investigate the mechanisms of apoptosis during differentiation of HL-60 cells induced by NO, the endogenous levels of Bcl-2 and Bax were assessed by immunoblotting. Treatment of cells with NOC 18 slightly reduced the level of Bcl-2 followed by Bax. These changes might be involved in the induction of apoptosis. The involvement of the activation of the interleukin-1 beta converting enzyme (ICE) family of proteases (caspases), such as ICE and CPP32, in the pathways was also investigated. CPP32, but not ICE, was strongly activated in response to NOC 18 stimulation, thereby implicating CPP32-like activity in the induction of apoptosis. Moreover, the possible involvement of tyrosine phosphorylation in apoptosis was investigated. Pretreatment of cells with herbimycin A, an inhibitor of tyrosine kinases, suppressed DNA fragmentation and CPP32-like activity, whereas pretreatment with vanadate, an inhibitor of tyrosine phosphatases, enhanced both parameters, suggesting that tyrosine phosphorylation might be involved in the pathways of apoptosis in HL-60 cells induced by NO.

Apoptosis↗
PubMed1997

Oxygen-dependent fragmentation of cellular DNA by nitric oxide.

Although active oxygen species and related metabolites, such as nitric oxide (NO), have been postulated to play important roles in the apoptosis of various cells, a precise mechanism leading to cell death remains to be elucidated. Recently we found that the lifetime of NO depends greatly on the concentration of environmental oxygen and that NO reversibly inhibits mitochondrial respiration and ATP synthesis; the inhibitory effect is stronger at physiologically low oxygen tension than under atmospheric conditions (Arch. Biochem. Biophys. 323, 27-32, 1995). The present work describes the effects of the NO-generating agent, 1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)-1-triazene (NOC 18) and oxygen tension on the respiration, ATP synthesis and apoptosis of HL-60 cells. When respiration was inhibited by NOC 18, cellular ATP levels decreased significantly and DNA fragmentation was elicited. Both events were enhanced by decreasing oxygen tension and suppressed by adding NO-trapping agents, such as 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO) and oxyhemoglobin. The fragmentation of cellular DNA was inhibited in a dose dependent manner by herbimycin A, a tyrosine kinase inhibitor. Fragmentation of the DNA of HL-60 cells was also induced either by peroxynitrite, superoxide or hydroxyl radical by some mechanism which was diminished by lowering the oxygen tension. These results indicated that the decrease in cellular ATP and activation of tyrosine kinase might play important roles in NO-induced apoptosis particularly under physiologically low oxygen tensions.

Adenosine Triphosphate↗