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Biomedical subjects

T Yasuda

Publications and source records attributed to T Yasuda.

At least 541 records · Page 30Linked to original sources
PubMed1993

Comparison of bactericidal activities of various disinfectants against methicillin-sensitive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus.

Various disinfectants were compared in terms of the duration of bactericidal activity against methicillin-sensitive Staphylococcus aureus (MSSA), and methicillin-resistant Staphylococcus aureus (MRSA), among S. aureus isolated in our hospital. Strains of S. aureus which showed minimum inhibitory concentrations of cloxacillin of less than 1.56 micrograms/ml and of 3.13 micrograms/ml or higher were designated MSSA and MRSA respectively. There was no difference in sensitivity to disinfectants between MSSA and MRSA. There was a great variation in the duration of bactericidal activity of chlorhexidine gluconate against these species with the majority requiring contact times of between 2 minutes and over 20 minutes. All strains except for one strain of MRSA were killed within 20 seconds after disinfection with benzalkonium chloride. All strains were killed within 20 seconds after disinfection with alkyldiaminoethylglycine hydrochloride or povidone-iodine.

Benzalkonium Compounds↗
PubMed1993

[MRI findings in patients with acute autonomic and sensory neuropathy].

Acute autonomic and sensory neuropathy (AASN), characterized by acute onset of extensive autonomic dysfunction and severe sensory deficits, was first described by Colan et al. (1978). We present two female patients with AASN in whom magnetic resonance imaging (MRI) confirmed such findings in the posterior column of the spinal cord. One patient was a 44-year-old woman who developed an upper respiratory tract infection followed in 2 weeks by numbness of the limbs and gait disturbance. There was orthostatic hypotension with syncope, paretic ileus, anhidrosis and urinary retention. There was a loss of sensation over the entire body, including the face, and deep tendon reflexes were generally absent. Neurophysiologic studies showed that sensory nerve action potentials and SSEPs were not evoked in the nerves examined. Sural nerve biopsy demonstrated severe axonal degeneration of the myelinated and unmyelinated fibers. Our second patient, a 27-year-old woman, exhibited similar clinical and laboratory features. The autonomic dysfunction in both patients improved gradually without drug treatment, but the sensory deficits--predominantly a loss of deep sensation--persisted for several years. In both patients, MRI revealed the T2*-weighted high intensity area in the fasciculus gracilis of the posterior column of the spinal cord. Such high intensity areas were present in all spinal segments. The severe and persistent sensory disturbance in these patients may have been caused by a lesion of the posterior column of the spinal cord following the involvement of the dorsal root ganglion cells, or ganglioneuronopathy, as demonstrated by MRI.

Acute Disease↗
PubMed1993

[A case of left ventricular aneurysm associated with acromegaly].

We performed a left ventricular aneurysmectomy for a left ventricular aneurysm associated with acromegaly in a 62-year-old man. Bromocriptine mesilate was administered to suppress high growth hormone (GH) levels, and there were no complications during or after the operation. The majority of patients with acromegaly die of cardiovascular diseases such as cardiomegaly, hypertension, arteriosclerosis of the coronary arteries, congestive heart failure, valvular disease, and arrhythmia. Ventricular aneurysm is a rare complication of acromegaly. In order to safely operate, it is important to control serum GH levels and pay special attention to the well-known complications of acromegaly such as diabetes mellitus and hypertension.

Acromegaly↗
PubMed1993

[Intra-arterial chemotherapy with 5-FU (weekly high dose 5-FU HAI) for the prevention of tumor recurrence in residual liver after hepatic resection of metastasis from colorectal cancer].

Intra-arterial cancer chemotherapy using an implantable reservoir was performed for the prevention of tumor recurrence in residual liver after resection of a metastatic tumor from colorectal cancer. Four cases of synchronous hepatic metastases and one case of metachronous hepatic metastasis, which were in H1 (2 cases) and H2 (3 cases), were treated. 5-FU was administered in a dose of 1,000 mg/m2 5 hours weekly (weekly high dose 5-FU HAI). The longest survival obtained is 1Y 11M. Other cases have survived for 1Y 7M, 1Y 12M, 9M, and 3M. Tumor recurrence was not observed in all cases except one. This case had a residual tumor because the complete resection was impossible. The tumor recurrence rate in patients treated with surgery alone at Nikko Memorial Hospital (n = 11) was 63.6%. The 1- and 2-year survival rate in these patients was 60.6% and 26.9%, respectively. As compared to these rates, the results of this study were very favorable. Although mild nausea and abdominal discomfort were observed in 1 patient, this adverse effect was reduced by administration of an anti-ulcer agent. Only a slight decrease of WBC and PLT counts was observed. Consequently, for residual liver after resection of hepatic metastasis from colorectal cancer, this intraarterial chemotherapy with 5-FU is considered to be effective to prevent tumor recurrence and thus to prolong survival.

Aged↗
PubMed1993

[Penetration into bone and joint tissues of rabbits and in vitro antibacterial activity of tosufloxacin].

The penetration of tosufloxacin (TFLX) into the bone and joint tissues of rabbits and its in vitro antibacterial activity were compared with those of lomefloxacin (LFLX) which is a efficacious drug for orthopedic infections. Serum levels of TFLX at 1, 2, 4 and 6 hours after oral administration (100 mg/kg) were 0.41, 0.65, 0.62 and 0.42 micrograms/ml, respectively. Except in synovial fluid and femur, TFLX concentrations in bone and joint tissues were higher than those in serum (0.69 approximately 1.92 micrograms/g in bone marrow of sternum, 0.55 approximately 1.53 micrograms/g in bone marrow of femur). TFLX concentrations in synovial fluid at 4 and 6 hours after the administration were equal to those in serum, which were lower than those of LFLX, but the ratio of tissue level/serum level of TFLX was similar to that of LFLX. TFLX was 8- to 64-fold more active than LFLX against Staphylococcus aureus (including methicillin-resistant S. aureus), Streptococcus pyogenes, Haemophilus influenzae, which are major pathogens of purulent osteomyelitis and arthritis. TFLX inhibited the growth of these bacteria at less than 0.39 micrograms/ml. These results indicate that TFLX is a useful drug for orthopedic infection.

Administration, Oral↗
PubMed1993

Measurement of deoxyribonuclease I activity in human tissues and body fluids by a single radial enzyme-diffusion method.

In the single radial enzyme-diffusion (SRED) method for assay of deoxyribonuclease I, a precisely measured volume of the enzyme solution is dispensed into a circular well in an agarose gel layer in which DNA and ethidium bromide are uniformly distributed. A circular dark zone is formed as the enzyme diffuses from the well radially into the gel and digests substrate DNA. The diameter of the dark circle of hydrolyzed DNA increases in size with time and correlates linearly with the amount of enzyme applied to the well. Thus, the SRED can be used for quantitation of deoxyribonuclease I with a limit of detection of 2 x 10(-6) unit. This corresponds to 1 pg of purified urine deoxyribonuclease I. We measured the deoxyribonuclease I activity of 17 different human tissues and body fluids from healthy donors. Urine samples showed the greatest activity, 6.0 +/- 2.2 kilo-units/g protein (mean +/- SD). Serum deoxyribonuclease I activity was 4.4 +/- 1.8 units/L.

Adult↗
PubMed1993

Altered localization of 73-kilodalton heat-shock protein in rat kidneys with gentamicin-induced acute tubular injury.

BACKGROUND: The constitutive 73-kilodalton heat-shock protein (HSP73) has been shown to have various essential functions in cells under both normal and stress conditions. In the present study, we observed serial localizations of HSP73 in rat kidneys with gentamicin-induced acute tubular injury. EXPERIMENTAL DESIGN: Sprague-Dawley rats received gentamicin (80 mg/kg/day) for 14 days, and developed acute proximal tubular injury. The intrarenal immunohistochemical distribution of HSP73 was examined by using a specific antibody against HSP73. In addition, HSP73 content in both isotonic buffer- and detergent-extractable renal fractions were measured by immunoblot analysis. RESULTS: After the gentamicin exposure, HSP73 moved from the nucleus to the cytoplasm, and accumulated in granules that were considered to be expressed within enlarged lysosomes in the injured proximal tubular epithelial cells. These granules started to appear from 36 hours after the first gentamicin exposure, enlarged in size until day 12, and gradually diminished after day 18. At day 27, the HSP73 localization pattern returned to that in the normal kidney. Moreover, significantly increased HSP73 protein bands were detected by immunoblot of detergent-extractable fractions from gentamicin-treated rat kidneys at from 36 hours to day 15 after the gentamicin exposure. CONCLUSIONS: Our findings suggest that HSP73 is rapidly induced as an insoluble form in injured lysosomes of the proximal tubular epithelial cells during gentamicin-induced acute tubular injury.

Animals↗
PubMed1992

Comparison of painful and painless left ventricular dysfunction recorded during ambulatory ventricular function monitoring in angina pectoris secondary to coronary artery disease.

Left ventricular (LV) function and the electrocardiogram of 55 patients with coronary artery disease and angina were monitored for a mean of 3.2 +/- 1.9 hours with an ambulatory LV function monitor. During the monitoring interval, patients performed daily activities such as sitting, walking, climbing stairs, and eating. Sixty episodes of transient reduction in ejection fraction of > 5% lasting > 60 seconds were observed in 24 patients; 13 episodes were associated with typical angina, but 47 were asymptomatic. Asymptomatic episodes had a shorter duration of ventricular dysfunction (116 +/- 49 vs 189 +/- 113 seconds; p < 0.05), and smaller increases in relative end-diastolic and end-systolic volumes (end-diastolic 0.9 +/- 5.4% vs 4.6 +/- 4.9% [p < 0.05], and end-systolic 21 +/- 11% vs 35 +/- 20% [p < 0.05]) than did symptomatic ones. When a subset of patients with both symptomatic and asymptomatic episodes were analyzed, similar results were observed: in asymptomatic episodes, duration was shorter (82 +/- 31 vs 200 +/- 110 seconds; p < 0.005), ejection fraction decrease was smaller (-7.3 +/- 2.6% vs -11.0 +/- 4.7%; p < 0.05), and end-systolic volume increase was smaller (23 +/- 12% vs 37 +/- 19%; p < 0.05). The data suggest that asymptomatic transient LV dysfunction is less severe and of shorter duration in patients with angina pectoris.

Angina Pectoris↗
PubMed1992

Influence of membrane fluidity on the assembly of Staphylococcus aureus alpha-toxin, a channel-forming protein, in liposome membrane.

By use of multilamellar phosphatidylcholine (PC) liposomes of different acyl composition and cholesterol content as model membranes, we studied whether or not membrane fluidity affects the assembly process of Staphylococcus aureus alpha-toxin. Under conditions using fluid and solid membranes, we assayed accessibility (or hemolytic activity) of liposome-bound alpha-toxin to rabbit erythrocytes added, hexamerization of membrane-bound toxin using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under nondenaturating conditions, and susceptibility of liposome-bound toxin to trypsin digestion. Our data indicated 1) that alpha-toxin bound to PC membrane as a hemolytically active monomer (or reversibly bound state); 2) that when the membrane was fluidized either by phase transition of PC or by inclusion of cholesterol over 20 mol %, the hemolytically active monomer of the toxin was irreversibly converted to nonhemolytic monomer (and/or unstable oligomer) in a first-order kinetics with a t1/2 of about 1 min, and thereafter hexamerization of the toxin gradually proceeded in the following 60-90 min; 3) that alpha-toxin might have different topology and/or conformation in PC membrane, depending on the presence or absence of cholesterol in the PC membrane; and 4) that coexistence of unsaturated acyl chain-carrying PC and cholesterol was a prerequisite for efficient hexamerization of alpha-toxin in membrane. Thus, increase in membrane fluidity promoted the assembly process of S. aureus alpha-toxin.

Animals↗
PubMed1992

Specific identification of human ribonucleases by antibodies produced against two synthetic peptides corresponding to the N- and C-terminal amino-acid sequences of human urinary secretory-type ribonuclease.

Antibodies were raised in rabbits by immunizing two synthetic peptides, which corresponded to the N- and C-terminal 15 residues, respectively, of human urinary secretory ribonuclease (RNase). These antibodies did not block the RNase activity, but reacted well with enzymes blotted onto a transfer membrane following electrophoresis, and discriminated strictly between secretory- and nonsecretory-type RNases. Therefore, these antibodies should to be valuable tools for the immunological identification of human RNases.

Amino Acid Sequence↗
PubMed1992

Heterogeneity of anticardiolipin antibodies defined by the anticardiolipin cofactor.

Anticardiolipin antibodies (aCL) found in sera from patients with SLE react with cardiolipin (CL) in the presence of a 50-kDa serum cofactor. The cofactor, which was identified to be beta 2-glycoprotein I by sequencing the N-terminal amino acids, not only enhances CL binding by antibodies in SLE but also depresses it by antibodies associated with syphilis. Cofactor-dependent binding of aCL in SLE to solid phase CL was competitively inhibited by the simultaneous addition of fluid phase CL but was unaffected by either prior or simultaneous addition of a high excess of the cofactor. Binding of aCL in syphilis to solid phase CL was competitively inhibited by either addition of the cofactor or fluid phase CL. aCL in SLE reacted with CL, PS, and PA in the presence of cofactor. In contrast, biotinyl-cofactor bound directly to these anionic phospholipids (PL) and also to PG. These results show that the cofactor-CL complex bears an epitope that confers recognition specificity for aCL in SLE, in contrast with direct CL recognition by syphilitic aCL. The direct binding of the cofactor to PL suggests that the cofactor dependence of aCL binding to PL is due to recognition by aCL of a unique epitope generated upon the formation of the cofactor-CL complex.

Amino Acid Sequence↗
PubMed1992

G4120, an Arg-Gly-Asp containing pentapeptide, enhances arterial eversion graft recanalization with recombinant tissue-type plasminogen activator in dogs.

The effects of G4120, a cyclic Arg-Gly-Asp (RGD) containing peptide which inhibits fibrinogen binding to the platelet receptor GPIIb/IIIa, on thrombolysis with recombinant tissue-type plasminogen activator (rt-PA) were investigated in a combined arterial and venous thrombosis model in heparinized dogs. The arterial thrombus model consisted of a 3 cm everted (inside-out) carotid arterial segment inserted into a transsected femoral artery which occludes within 30 min with platelet-rich material and which is resistant to recanalization with 0.5 mg/kg rt-PA. The venous thrombus was a 125I-fibrin labeled whole blood clot produced in the contralateral femoral vein. In 5 dogs given an intravenous bolus of 0.05 mg/kg G4120 followed by a continuous infusion of 0.05 mg/kg per hour for 3 h (group I), arterial occlusion persisted throughout a 4 h observation period and was still present at 24 h in all dogs; the extent of venous clot lysis after 120 min was 27 +/- 7%. In 5 dogs given the same infusion of G4120 in combination with 0.5 mg/kg rt-PA over 60 min, recanalization of the arterial graft occurred in all dogs, within 13 +/- 2 min and persisted throughout the observation period of 4 h (p = 0.01 versus G4120 or rt-PA alone); at 24 h, however, all grafts were occluded. Venous clot lysis in this group was 75 +/- 8% (p = 0.002 versus G4120 alone and p = NS versus rt-PA alone). Pathologic analysis revealed platelet-rich or mixed thrombus with platelet-rich and erythrocyte-rich zones.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

Effect of fatty acyl domain of phospholipids on the membrane-channel formation of Staphylococcus aureus alpha-toxin in liposome membrane.

By use of carboxyfluorescein-loaded multilamellar liposomes prepared from synthetic phosphatidylcholine (PC) or sphingomyelin and cholesterol in a molar ratio of 1:1, we studied whether or not fatty acyl domain of the phospholipids affects the membrane-damaging action (or channel formation) of Staphylococcus aureus alpha-toxin on the phospholipid-cholesterol membranes. Our data indicated: (1) that toxin-induced carboxyfluorescein-leakage from the liposomes composed of saturated fatty acyl residue-carrying PC and cholesterol was decreased with increasing chain length of the acyl residues between 12 and 18 carbon atoms, although toxin-binding to the liposomes was not significantly affected by the length of fatty acyl residue; (2) that unsaturated fatty acyl residue in PC or sphingomyelin molecule conferred higher sensitivity to alpha-toxin on the phospholipid-cholesterol liposomes, compared with saturated fatty acyl residues; and (3) that hexamerization of alpha-toxin, estimated by SDS-polyacrylamide gel electrophoresis, occurred more efficiently on the liposomes composed of PC with shorter fatty acyl chain or unsaturated fatty acyl chain. Thus, hydrophobic domain of the phospholipids influences membrane-channel formation of alpha-toxin in the phospholipid-cholesterol membrane, perhaps by modulating packing of phospholipid, cholesterol and the toxin in membrane.

Diglycerides↗