Search PubMed⌕ Search

Biomedical subjects

T Satoh

Publications and source records attributed to T Satoh.

At least 379 records · Page 21Linked to original sources
PubMed1998

Characterization of a cDNA encoding CuZn-superoxide dismutase from the liverwort Marchantia paleacea var. diptera.

Suspension-cultured cells of the liverwort Marchantia paleacea var. diptera contain a cytosolic CuZn-superoxide dismutase (SOD) whose N-terminal amino acid sequence is similar to those of the isozymes found in chloroplasts of higher plants [Tanaka et al. (1996) Plant Cell Physiol. 37: 523]. A cDNA (MSODCc) encoding the cytosolic CuZn-SOD was isolated from cDNA library constructed from a liverwort cell suspension culture. The deduced amino acid sequence showed a higher degree of homology with the sequences of CuZn-SODs in chloroplasts than those in the cytosol of higher plants and an unique additional peptide in the C-terminal region, but no plastid transit sequence. Northern blotting using MSODCc as a probe and immunoblot analysis with antiserum against the enzyme revealed that the steady state level of transcript was not affected by copper, but both CuZn-SOD protein and its activity increased.

Amino Acid Sequence↗
PubMed1998

Effects of sevoflurane and isoflurane on renal function and on possible markers of nephrotoxicity.

BACKGROUND: Low-flow sevoflurane anesthesia is associated with increasing circuit concentrations of compound A, which is nephrotoxic in rats, but the effect of compound A and low-flow sevoflurane anesthesia on renal function in humans is unclear. The authors compared the effects of high- and low-flow sevoflurane and isoflurane anesthesia on renal function and on several possible markers of nephrotoxicity in humans. METHODS: Forty-two patients without preexisting renal disease underwent either low-flow isoflurane (1 l/min, n = 14), low-flow sevoflurane (1 l/min, n 14), or high-flow sevoflurane (6 l/min, n = 14) anesthesia for body-surface-area surgery scheduled to last at least 4 h. Twenty-four-hour urinary excretion of N-acetyl-beta-glucosaminidase (NAG), beta2-microglobulin, protein, glucose, blood urea nitrogen (BUN), and serum creatinine concentrations were measured before and after anesthesia. RESULTS: There were no differences in blood urea nitrogen, creatinine, and creatinine clearance among the three groups after anesthesia. Increased urinary N-acetyl-beta-glucosaminidase excretions were seen in the low-flow and high-flow sevoflurane groups, but not in the low-flow isoflurane group (P < 0.01). Ten patients in the low-flow sevoflurane group had 24-h urinary excretion of protein that exceeded the normal ranges after anesthesia, but only one patient in the isoflurane and none in the high-flow sevoflurane groups had this. CONCLUSIONS: Low-flow sevoflurane anesthesia was associated with mild and transient proteinuria. However, the observed proteinuria was not associated with any changes in blood urea nitrogen, creatinine, and creatinine clearance in these patients with no preexisting renal disease.

Acetylglucosaminidase↗
PubMed1998

Prognosis of osteosarcoma with pulmonary metastases at initial presentation is not dismal.

Prognosis of osteosarcoma has been improved markedly with the introduction of effective, intensive chemotherapy. However, there are many reports that indicate that the prognosis of osteosarcoma with pulmonary metastases at the initial presentation is poor. One hundred seventeen patients with osteosarcoma involving the extremities were treated at the Chiba Cancer Center from 1976 to 1995. Of these, nine (7.6%) patients had pulmonary metastases at initial presentation; these nine patients are the subjects of this article. There was an average of 0.9 pulmonary metastatic lesions at initial presentation seen on plain chest radiographs, an average 2.9 lesions seen on computed tomograms of the chest, and an average 12.7 lesions found at thoracotomy in these nine patients. The pulmonary metastatic lesions that could not be detected by computed tomography of the chest were resected by thoracotomy. Three patients died, and six patients are alive, with the 5-year survival being 64.8%. Intensive chemotherapy and aggressive surgical therapy were done for these patients with osteosarcoma with pulmonary metastases at initial presentation, and it is thought that this improved the prognosis of these patients. Pulmonary metastases of osteosarcoma at initial presentation do not always indicate a hopeless prognosis.

Adolescent↗
PubMed1998

Necrobiosis lipoidica-like skin lesions in systemic sarcoidosis.

A 62-year-old woman with systemic sarcoidosis developed erythematous plaques on her lower legs. Clinically, two kinds of skin lesions were distinguished; one type formed brownish-red plaques with induration suggesting plaque-type skin sarcoid, and the other formed purplish erythematous plaques with atrophic centers resembling necrobiosis lipoidica. In spite of this clinical appearance, a biopsy specimen from one of the latter lesions revealed typical skin sarcoid histology composed of discrete non-caseating granulomas, while that from one of the other lesions showed necrobiotic changes of collagen bundles surrounded by epitheloid histiocytes and foreign-body giant cells. Because cutaneous involvement of sarcoidosis may mimic necrobiosis lipoidica clinically and/or histologically, we diagnosed her skin lesions as necrobiosis-like skin sarcoid.

Collagen↗
PubMed1998

Cesium-induced atrial tachycardia degenerating into atrial fibrillation in dogs: atrial torsades de pointes?

INTRODUCTION: In this study, we investigated whether the potassium channel blocker, cesium chloride (CsCl), which is capable of producing early after-depolarizations (EADs) and polymorphic ventricular tachyarrhythmias resembling torsades de pointes, might exert similar effects in the atria. METHODS AND RESULTS: In nine anesthetized open chest dogs, 5 mL of CsCl in incremental doses (0.05, 0.1, 0.15, 0.2, 0.25 mM/mL) was injected into the sinus node artery to induce atrial arrhythmias. A polymorphic atrial tachycardia (P-AT) apparently triggered by an EAD and degenerating into atrial fibrillation resulted after CsCl administration in six dogs, but not in the remaining three dogs at any dose of CsCl. The P-AT developed during a normal atrial rate (110+/-13.5 beats/min) on six occasions and during atrial bradycardia (58.6+/-17.9 beat/min) five times. P-AT that occurred during a normal atrial rate had the last normal P wave temporally closely related to ventricular activation, with a VA interval of almost zero (1.3+/-3.3 msec), whereas P-AT induced from an atrial bradycardia had no relation to ventricular activation. The %EAD in the atrial bradycardia group (13.9+/-2.5) exceeded that in the normal atrial rate group (10.9+/-1.8) (P < 0.05). CONCLUSION: CsCl induces atrial EADs that provoke P-AT that degenerates into atrial fibrillation. P-AT has some characteristics similar to ventricular torsades de pointes.

Animals↗
PubMed1998

TNF-alpha, RANTES, and MCP-1 are major chemoattractants of murine Langerhans cells to the regional lymph nodes.

We have previously reported that lymph node cells generated chemotactic factors for Langerhans cells (LCs) in the induction phase of contact dermatitis. In order to clarify the chemotactic factors involved in migration to the regional lymph nodes, we investigated the migratory activity of murine LCs toward several cytokines and chemokines in vitro. One-day cultured LC-enriched epidermal cells were added to the upper compartment of a modified Boyden chamber and cytokines were added to the lower compartment. We counted dendritic cells migrated to the lower chamber as LCs under phase contrast microscopy. About 99% of migrated dendritic cells were positively reacted with anti-Ia(d) and NLDC145 antibodies and considered to be LCs. We could detect LC migration more accurately by this direct examination than by counting the migrated cells in the filter membrane of a Boyden chamber. In our system, migration of murine epidermal LCs was stimulated by TNF-alpha, RANTES and MCP-1, but not by GM-CSF, IL-1beta, IL-4, and IL-6. TNF-alpha induced LC migration at concentrations from 4 x 10(3) U/ml to 5 x 10(4) U/ml. RANTES at concentrations from 10 to 100 ng/ml and MCP-1 at a concentration of 100 ng/ml induced LC migration in a dose-dependent manner. These data confirmed that TNF-alpha, RANTES, and MCP-1 induced LC migration from epidermis during contact sensitization.

Animals↗
PubMed1998

[Experimental studies of polymorphonuclear leukocyte on mandibular bone infection model in rabbit].

Polymorphonuclear leukocytes (PMN) play important roles in the prevention of infection at an early stage. We studied the function of these leukocytes using rabbit models of mandibular bone infection to evaluate the conditions which could not be reproduced in human beings Streptococcus milleri NCTC7331 and Bacteroides fragillis NCTC9343 were inoculated into the mandibular bone of rabbits using the Satoh-Heimdahl method, to produce supposed multiple infection models. Rabbits inoculated with these bacteria were used as a test group, and animals with surgically induced inflammation were used as a control group. We compared the number of leukocytes, the function of PMN, and histopathologic findings. 1) The number of leukocytes increased after treatment, reached a perk on day 3, gradually diminished later, but remained slightly higher than the baseline level on day 7, with persistence of inflammation in both groups. 2) Adhesiveness, ability to migrate and NBT reduction, were accelerated in both groups. 3) These functions of PMN accelerated more in the test group because the bacteria inoculated induced stronger inflammatory reactions and activated a series of infection defense mechanisms in the hosts. 4) Histopathologic examination after treatment showed invasion of inflammatory cells, predominantly leukocytes, in both groups, but heavier and more extensive infiltration in the group treated with the bacteria. All measurements were higher in the test group than the control group. These results showed that in the test group, causative or accompanied microorganisms activated the host's infection defense mechanisms and accelerated the functioning of PMN at an acute stage of infection.

Animals↗
PubMed1998

J-104,871, a novel farnesyltransferase inhibitor, blocks Ras farnesylation in vivo in a farnesyl pyrophosphate-competitive manner.

Farnesylation of the activated ras oncogene product by protein farnesyltransferase (FTase) is a critical step for its oncogenic function. Because squalene synthase and FTase recruit farnesyl pyrophosphate as a common substrate, we modified squalene synthase (SS) inhibitors to develop FTase inhibitors. Among the compounds tested, a novel FTase inhibitor termed J-104,871 inhibited rat brain FTase with an IC50 of 3.9 nM in the presence of 0.6 microM farnesyl pyrophosphate (FPP), whereas it scarcely inhibited rat brain protein geranylgeranyltransferase-I or SS. The in vitro inhibition of rat brain FTase by J-104,871 depends on the FPP concentration but not on the concentration of Ras peptide. Thus, in vitro studies strongly suggest that J-series compounds have an FPP-competitive nature. J-104,871 also inhibited Ras processing in activated H-ras-transformed NIH3T3 cells with an IC50 value of 3.1 microM. We tested the effects of lovastatin and zaragozic acid A, which modify cellular FPP levels, on Ras processing of J-104,871. Lovastatin, a hepatic hydroxymenthyl coenzyme A reductase inhibitor that reduced the cellular FPP pool, increased the activity of J-104,871, whereas 3 microM zaragozic acid A, an SS inhibitor that raised the FPP level, completely abrogated the activity of J-104,871 even at 100 microM. These results suggest that J-104,871 inhibits FTase in an FPP-competitive manner in whole cells as well as in the in vitro system. Furthermore, J-104,871 suppressed tumor growth in nude mice transplanted with activated H-ras-transformed NIH3T3 cells.

3T3 Cells↗
PubMed1998

Isolation of a periplasmic molecular chaperone-like protein of Rhodobacter sphaeroides f. sp. denitrificans that is homologous to the dipeptide transport protein DppA of Escherichia coli.

A periplasmic protein has been found to prevent aggregation of the acid-unfolded dimethyl sulfoxide reductase (DMSOR), the periplasmic terminal reductase of dimethyl sulfoxide respiration in the phototroph Rhodobacter sphaeroides f. sp. denitrificans, in a manner similar to that of the Escherichia coli chaperonin GroEL (Matsuzaki et al., Plant Cell Physiol. 37:333-339, 1996). The protein was isolated from the periplasm of the phototroph. It had a molecular mass of 58 kDa and had no subunits. The sequence of 14 amino-terminal residues of the protein was completely identical to that of the periplasmic dipeptide transport protein (DppA) of E. coli. The 58-kDa protein prevented aggregation to a degree comparable to that of GroEL on the basis of monomer protein. The 58-kDa protein also decreased aggregation of guanidine hydrochloride-denatured rhodanese, a mitochondrial matrix protein, during its refolding upon dilution. The 58-kDa protein is a kind of molecular chaperone and could be involved in maintaining unfolded DMSOR, after secretion of the latter into the periplasm, in a competent form for its correct folding.

Amino Acid Sequence↗
PubMed1998

The mammalian carboxylesterases: from molecules to functions.

Multiple carboxylesterases (EC 3.1.1.1) play an important role in the hydrolytic biotransformation of a vast number of structurally diverse drugs. These enzymes are major determinants of the pharmacokinetic behavior of most therapeutic agents containing ester or amide bonds. Carboxylesterase activity can be influenced by interactions of a variety of compounds either directly or at the level of enzyme regulation. Since a significant number of drugs are metabolized by carboxylesterase, altering the activity of this enzyme class has important clinical implications. Drug elimination decreases and the incidence of drug-drug interactions increases when two or more drugs compete for hydrolysis by the same carboxylesterase isozyme. Exposure to environmental pollutants or to lipophilic drugs can result in induction of carboxylesterase activity. Therefore, the use of drugs known to increase the microsomal expression of a particular carboxylesterase, and thus to increase associated drug hydrolysis capacity in humans, requires caution. Mammalian carboxylesterases represent a multigene family, the products of which are localized in the endoplasmic reticulum of many tissues. A comparison of the nucleotide and amino acid sequence of the mammalian carboxylesterases shows that all forms expressed in the rat can be assigned to one of three gene subfamilies with structural identities of more than 70% within each subfamily. Considerable confusion exists in the scientific community in regards to a systematic nomenclature and classification of mammalian carboxylesterase. Until recently, adequate sequence information has not been available such that valid links among the mammalian carboxylesterase gene family or evolutionary relationships could be established. However, sufficient basic data are now available to support such a novel classification system.

Animals↗
PubMed1998

Elevated serum interferon-gamma in atopic asthma correlates with increased airways responsiveness and circadian peak expiratory flow variation.

Interleukin (IL)-4, IL-5 and interferon (IFN)-gamma are thought to play an important role in chronic airway inflammation in asthmatic subjects. Increased airways responsiveness and nocturnal airway obstruction are important clinical manifestations of asthma. The aim of this study was to investigate whether IL-4, IL-5 and IFN-gamma values are elevated in atopic asthma and correlate with its clinical manifestations. Serum IL-4, IL-5 and IFN-gamma levels of 17 atopic asthmatics and eight nonatopic healthy subjects were determined at 16:00 and 04:00 h by a chemiluminescence enzyme-linked immunosorbent assay (ELISA) method. The clinical manifestation of asthma was determined by assessment of the degree of airway obstruction, airways responsiveness to methacholine and severity of nocturnal airway obstruction, defined as the mean circadian (16:00-04:00 h) peak expiratory flow (PEF) variation. Serum IL-4, IL-5 and IFN-gamma levels were significantly higher in asthmatic subjects as compared to healthy controls, both at 16:00 and 04:00 h. In asthmatic subjects serum IFN-gamma at both time points correlated significantly with the provocative concentration of methacholine causing a 20% fall in forced expiratory volume in one second (PC20,meth) (rho= - 0.55) and with the mean 16:00-04:00 h PEF variation (rho = 0.53). In contrast, no relationship was found between the levels of IL-4 and IL-5 and the parameters of clinical manifestation of asthma. The results suggest that the serum interferon-gamma level is a reflection of the severity of airway inflammation in atopic asthma. More studies are needed to detect the cellular sources and to clarify the exact roles of interferon-gamma and other pro-inflammatory cytokines in asthma.

Adolescent↗
PubMed1998

Stimulation of the preprothyrotropin-releasing hormone gene by epidermal growth factor.

Regulation of the expression of the prepro-TRH (ppTRH) gene by epidermal growth factor (EGF) was investigated. The i.p. injection of EGF significantly stimulated hypothalamic ppTRH messenger RNA levels in rats. To clarify whether this stimulatory effect of EGF could be exerted at the level of gene transcription, the 5'-flanking region (-1893/+127) of the mouse ppTRH gene fused to a luciferase reporter gene was transiently transfected into pituitary GH4C1 cells, and the effect of EGF on gene transcription was measured by a luciferase assay. EGF stimulated ppTRH gene promoter activity in a time- and dose-dependent manner. Deletion analysis revealed that two different regions of the promoter, between -254 and -218 [EGF response element-1 (EGFRE1)] and between -130 and -84 (EGFRE2) were required for full stimulation by EGF. The two EGFREs possessed putative binding sequences for the transcription factor Sp1, and they functioned cooperatively in heterologous promoters. Nuclear extracts from GH4C1 cells specifically bound those two EGFREs in gel retardation assays. Two protein-DNA complexes were found on EGFRE1, whereas four complexes were observed on EGFRE2. Although the binding of nuclear extracts to EGFRE1 was competed for by the consensus Sp1 binding sequence, the complexes on EGFRE1 were not supershifted by an Sp1 antibody. Formation of the slower migrating protein complex on EGFRE1 was prevented by EDTA, suggesting that one of the EGFRE1-binding proteins might be an Sp1-related zinc finger protein. Competition and supershift experiments demonstrated that the EGFRE2-binding protein showing that the slowest migration possessed a characteristic similar to that of Sp1. Selective mutations of the Sp1-binding site in EGFRE2 markedly diminished the EGF-induced stimulation. These results suggest that EGF may function as a positive regulator of ppTRH gene expression, and that the stimulatory effect may be mediated through a cooperative interaction between Sp1 or Sp1-related proteins and additional factors that bind to two separate DNA regions.

Animals↗
PubMed1998

Screening of an inhibitor of the tetracycline efflux pump in a tetracycline-resistant clinical-isolate of Staphylococcus aureus 743.

Clinically-isolated methicillin-resistant Staphylococcus aureus (MRSA) strain 743 exhibited resistance to tetracycline as judged from the active efflux of the drug. The efflux of tetracycline was inhibited by an uncoupler, carbonyl cyanide m-chlorophenylhydrazone (CCCP), and minocycline. Inhibitors of the efflux pump were examined in this strain to determine the cellular accumulation of tetracycline. Out of seven compounds examined, three caused a significant increase in the cellular concentration of tetracycline by inhibiting the efflux pump. Two of them seem to be energy inhibitors. Ro 07-3149 inhibited the efflux pump without affecting the energy state, and exhibited very low antibacterial activity but showed weak synergy with tetracycline.

Anti-Bacterial Agents↗
PubMed1998

Evaluation of propolis (II): effects of Brazilian and Chinese propolis on histamine release from rat peritoneal mast cells induced by compound 48/80 and concanavalin A.

To establish a biological method for evaluating propolis and to reveal their anti-allergic action, the effects of the ethanol and water extracts (EA-ET and WA-WT, respectively) from Brazilian, Chinese and Japanese propolis on the histamine release induced by compound 48/80 and concanavalin A (Con A) were investigated. The relation between the inhibitory activities of these extracts on the histamine release and their E(1 cm)1% values were also examined. As a result, the following was found: 1) 0.003-0.01% ethanol and 0.03-0.1% water extracts inhibited the histamine release induced by compound 48/80 and Con A, and the inhibitory potencies of the former extracts were more than 10 times stronger than those of the latter extracts, making it clear that both the ethanol and water extracts possess an anti-allergic action; 2) most of the ethanol and water extracts responded to the histamine release induced by both the histamine releasers in a concentration-dependent manner; 3) the inhibitory activities of 0.003% EM from Hebei Province, EP from Sichuan Province, EQ from Zhejiang Province and ER from Anhui Province in China were weaker than those of 0.01% corresponding extracts, whereas 0.001% ED-EH from Brazilian propolis, EM, EN from Henan Province in China and EP-ER promoted the Con A-induced histamine release of more than 10%, suggesting that such extracts must be carefully given to humans; 4) the inhibitory potencies of only 0.03-0.1% water extracts from Chinese propolis on the Con A-induced histamine release related excellently with their E(1 cm)1% values; 5) from the results of the relation between the inhibitory potencies of the propolis extracts and their E(1 cm)1% values, it was suggested that an unknown compound, being a poorly water-soluble compound which is a non-flavonoid, with an anti-allergic action is contained in propolis; 6) to precisely evaluate the anti-allergic action of the propolis, the biological method, which measures the inhibitory activities of the propolis extracts on histamine release, was markedly superior to the physicochemical method.

Animals↗
PubMed1998

Alternation in the flutter wave morphology during radiofrequency catheter ablation for common atrial flutter.

A linear lesion created at the right atrial isthmus by radiofrequency current application can successfully eliminate common atrial flutter (AF). The mechanism of unsuccessful cases has not yet been well delineated. This study sought to investigate the cause of unsuccessful cases of radiofrequency catheter ablation of AF. Sixty-six patients with refractory common AF were referred for radiofrequency catheter ablation. Radiofrequency current was applied to the right atrial isthmus between the inferior vena cava and tricuspid annulus or between the coronary sinus orifice and tricuspid annulus. In 5 (8%) of the 66 patients, a morphological change of the flutter wave was observed in the 12-lead ECG concomitant with the change of the atrial excitation sequence during the delivery of radiofrequency energy without the termination of atrial flutter. In 8 (12%) patients, the morphology of the new AF wave, which was provoked electrically after the termination of the original AF, was different, and the average flutter cycle length also differed in 3 cases (2%). The results of radiofrequency application could be misinterpreted as unsuccessful when the occurrence of another, different type of AF has been overlooked following the elimination of the original AF during the radiofrequency catheter ablation procedure. It is possible that the flutter circuit can take an alternative pathway despite the complete conduction block at the right atrial isthmus.

Adult↗
PubMed1998

Clinical study of the effectiveness of a dual amplified immunoassay (IDEIA PCE Chlamydia) for the diagnosis of male urethritis.

A clinical study of patients with male urethritis (n=316) was undertaken to determine the sensitivity potential for a new dual amplified immunoassay (IDEIA PCE Chlamydia). Increased sensitivity (98.8%, 84/85) was obtained for IDEIA PCE Chlamydia compared to a conventional antigen detection test (IDEIA Chlamydia, 81.2%, 69/85) when testing urine samples. In a smaller patient population (n=104) the positivity rate for the first-void urine tested with IDEIA PCE Chlamydia of 30.8% (32/104) was similar to the 27.9% (29/104) obtained from urethral swabs tested with a DNA probe assay (PACE 2). The increased sensitivity of the test was confirmed with a commercial PCR kit (Amplicor) and nested PCR. The IDEIA PCE Chlamydia kit has the sensitivity potential to be a clinically reliable alternative for detecting Chlamydia trachomatis.

Chlamydia Infections↗