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T Shimada

Publications and source records attributed to T Shimada.

At least 703 records · Page 39Linked to original sources
PubMed1991

Relationship between redistribution on exercise thallium-201 scintigraphy and repetitive ventricular premature beats in patients with recent myocardial infarction.

The relationship between myocardial ischemia detected by exercise thallium-201 scintigraphy and repetitive ventricular premature beats (VPBs) during ambulatory monitoring was evaluated in 57 patients with recent myocardial infarction. Multivariate analysis was performed to obtain the relatively important factor related to repetitive VPBs with the use of the following variables: age, redistribution, left ventricular ejection fraction, serum potassium and magnesium concentration, QRS score, left ventricular aneurysm, and the number of diseased vessels. Thirty-five patients had redistribution, but only three of them had repetitive VPBs during exercise testing. The average heart rate before 79% of 398 episodes of repetitive VPBs during ambulatory monitoring was in the range of 56 to 70/min. These data indicate that most of repetitive VPBs during ambulatory monitoring were not provoked by exercise-induced acute myocardial ischemia. However, redistribution was found to be an important factor associated with repetitive VPBs. The electrical abnormality relating to a substrate characterized by chronic reversible ischemia may explain the association between redistribution and repetitive VPBs.

Adult↗
PubMed1991

Late potentials in progressive muscular dystrophy of the Duchenne type.

This study describes the late potentials (LPs) obtained by signal-averaged electrocardiography (SAECG) in 66 patients with Duchenne's progressive muscular dystrophy (DMD). It also assesses the possible relationships between LPs and the severity of DMD, and the findings of two-dimensional echocardiography, as well as ventricular arrhythmias examined with the Holter system. SAECGs were performed with a Marquette MAC-1 unit. Based on Swinyard-Deaver's system of stages, ranging from the mildest, S1, to the most severe, S8, one patient each could be assigned to S2 and S4, 6 to S5, 20 to S6, 21 to S7, and 17 to S8. LPs were observed in 21 of the 66 patients (32%), including 3 of the 20 assigned to S6 (15%), 10 of the 21 in S7 (48%), and 8 of the 17 in S8 (47%). The total wall motion index evaluated by the method of Hegar was significantly greater in the patients with LPs (8.4 +/- 4.4) than in those without LPs (5.8 +/- 3.1) (p less than 0.05). The incidence of LPs was found to be higher in the dilated cardiomyopathy (DCM) type (8 of 12;67%) than in the normal type (9 of 41;22%) (p less than 0.01). The incidence of ventricular premature complexes (VPCs) was significantly higher in patients with LPs (13 of 21;62%) than in those without LPs (13 of 45;29%) (p less than 0.05). No sustained ventricular tachycardia (VT) was observed, although nonsustained VT was noted in three patients with LPs. The LPs in patients with DMD were thus associated with left ventricular dysfunction, and the presence of LPs might be correlated with the extent of myocardial derangement in DMD.

Adolescent↗
PubMed1991

Indiscriminate activity from the B19 parvovirus p6 promoter in nonpermissive cells.

B19 parvovirus is absolutely tropic for human erythroid progenitor cells. Among the untested mechanisms underlying this tropism is the possibility of cell-specific positive regulation of the promoter in permissive cells. Using the bacterial chloramphenicol acetyltransferase and firefly luciferase reporter genes, we detected strong activity from the B19 P6 promoter in transfected nonpermissive cells. Very high-level expression was seen in a T lymphoblastoid cell line, CEM. No transcriptional enhancement occurred in an erythropoietin-dependent semipermissive cell line. A putative second B19 promoter at map unit 44 (P44) was nonfunctional and unable to confer tissue specificity. Thus, tropism is unlikely to be regulated at the level of transcriptional initiation from either the P6 or P44 promoter.

Cell Line↗
PubMed1991

Upstream sequences within the terminal hairpin positively regulate the P6 promoter of B19 parvovirus.

For the B19 parvovirus P6 promoter, a 96-nt minimal truncation mutant retained activity in transient reporter gene assays. Deletion of sequences further upstream from this minimal promoter markedly diminished reporter activity in certain cell lines. This upstream region lies within the terminal hairpin from -249 to -157 and contains a 14-nt sequence that is protected by DNase I footprinting. The exact sequence is directly repeated further within the hairpin, suggesting a regulatory role. The hairpin termini of parvoviruses were known to serve as origins of replication and to catalyze virion packaging. We now suggest that, in addition to these functions, they exert cis-acting effects on B19 P6-promoted gene expression.

Base Sequence↗
PubMed1991

19-hydroxyandrostenedione does not modulate [3H]aldosterone binding to human mononuclear leucocytes and rat renal cytosol.

To verify the aldosterone amplifying action of 19-hydroxyandrostenedione (19-OH-AD), we investigated [3H]aldosterone and [3H]19-OH-AD binding to type I (mineralocorticoid) receptor in the renal cytosol of adrenalectomized and ovariectomized rat, and human mononuclear leucocytes (MNL). In the [3H]aldosterone binding study, the cytosol was incubated with [3H]aldosterone and 200-fold RU28362 (11 beta,17 beta-dihydroxy-6-methyl,17 alpha-(1-propynyl)-androsta-1,4,6- trien-3-one), a pure glucocorticoid, with or without 19-OH-AD. Scatchard plots of [3H]aldosterone binding to cytosol with 0.2 or 20 nM 19-OH-AD or without 19-OH-AD were linear. Dissociation constants (Kd) and maximum bindings (Bmax) without 19-OH-AD, and with 0.2 and 20 nM 19-OH-AD were: 0.71 +/- 0.03 nM and 23.0 +/- 3.4 fmol/mg protein (mean +/- SD, n = 3), 0.72 +/- 0.05 nM and 23.1 +/- 2.3 fmol/mg protein (n = 3), and 0.77 +/- 0.04 nM and 22.9 +/- 4.8 fmol/mg protein (n = 3), respectively. 19-OH-AD did not significantly change the Kd and Bmax of [3H]aldosterone binding. A high concentration of 19-OH-AD slightly displaced 0.2 or 5 nM [3H]aldosterone bound to cytosol. In human MNL, Scatchard plots of [3H]aldosterone binding with both 0.2 and 20 nM 19-OH-AD and without 19-OH-AD were linear. Kd and Bmax were, respectively, 1.00 nM and 780 sites/cell in the absence of 19-OH-AD, and 1.07 nM and 774 sites/cell in the presence of 0.2 nM 19-OH-AD. Without 19-OH-AD they were, respectively, 0.95 nM and 551 sites/cell, and 1.10 nM and 560 sites/cell with 20 nM 19-OH-AD. A high concentration of 19-OH-AD slightly displaced 0.2 or 5 nM of [3H]aldosterone bound to MNL. In both tissues, there was no obvious specific binding of [3H]19-OH-AD within the range of 1-60 nM. The above results suggest that the amplifying effect of 19-OH-AD on aldosterone mineralocorticoid action may not occur at the binding site of aldosterone to type I receptor, and that 19-OH-AD itself may not have any direct or indirect mineralocorticoid actions on the steroid receptor-mediated process in the rat kidney and human MNL.

Adrenalectomy↗
PubMed1991

Roles of different cytochrome P450 enzymes in bioactivation of the potent hepatocarcinogen 3-methoxy-4-aminoazobenzene by rat and human liver microsomes.

The potent hepatocarcinogen 3-methoxy-4-aminoazobenzene (3-MeO-AAB) has been reported to be bioactivated to mutagenic intermediates by rat liver microsomal cytochrome P450 (P450) and to be a selective inducer of rat P450IA2. In this study we have further investigated the roles of individual rat and human P450 enzymes in the bioactivation of this hepatocarcinogen in a Salmonella typhimurium TA1535/pSK1002 system where umu response is indicative of DNA damage. 3-MeO-AAB was found to be bioactivated by liver microsomal enzymes from rats and humans in this assay system. The liver microsomal activities are increased by pretreatment of rats with various P450 inducers such as phenobarbital (PB), beta-naphthoflavone (BNF), dexamethasone (DEX), acetone, ethanol, isoniazid (INH), diphenylhydantoin and valproic acid, and can be inhibited considerably by SKF-525A and metyrapone. alpha-Naphthoflavone (ANF) is also an inhibitor for the reaction catalyzed in BNF-treated rats, but stimulated the microsomal activity in DEX-treated rats. Evidence has also been obtained that specific antibodies raised against P450IIB1, P450IA1 or IA2, P450IIE1, and P450IIIA2 inhibited the activation in liver microsomes from rats pretreated with PB, BNF, INH and DEX respectively, suggesting the possible roles of several P450 enzymes in the bioactivation of 3-MeO-AAB. The results obtained with reconstituted monooxygenase systems containing various rat P450 enzymes are highly supportive of this conclusion. Human liver microsomal activation of 3-MeO-AAB was also inhibited to various extents by antibodies raised against P450IA2, P450MP, P450IIE1 and P450IIIA4. In a reconstituted system containing purified forms of human P450, P450IA2 was the most active in catalyzing 3-MeO-AAB, followed by P450IIIA4 and P450MP. ANF, a known activator of P450IIIA-catalyzed reactions, caused an increase in activation of 3-MeO-AAB in human liver microsomal and P450IIIA4- and P450MP-containing reconstituted systems. From these results it is concluded that multiple P450 enzymes in rat and human liver microsomes are involved in the bioactivation of 3-MeO-AAB, regardless of its selective induction of the rat P450IA2 gene.

Animals↗
PubMed1991

Biochemical and genetic characterization of autoagglutinating phenotypes of Aeromonas species associated with invasive and noninvasive disease.

The genetic characteristics and biochemical and structural properties of a number of autoagglutinating (AA) strains of Aeromonas associated with invasive and noninvasive disease in humans and infections in animals and from environmental sources were investigated. Of 27 strains analyzed by multilocus enzyme typing and DNA hybridization studies, 25 (93%) were confirmed to belong to either hybridization group 1 (phenospecies and genospecies Aeromonas hydrophila) or 8 (phenospecies Aeromonas sobria; genospecies Aeromonas veronii). Further analysis of 19 of these strains indicated that four major groups could be identified on the basis of serologic and surface characteristics, protein and lipopolysaccharide composition, and virulence properties; these groupings held true regardless of the site of isolation or disease process involved. The major AA+ group identified was serogroup O:11, whose strains possessed an S layer, were resistant to the bactericidal activity of normal serum, and were pathogenic in mice. The results suggest a set of useful phenotypic and structural markers for identification of specific subsets of mesophilic Aeromonas involved in a wide range of infections in the animal kingdom.

Aeromonas↗
PubMed1991

Purification and characterization of acidic form of glutathione S-transferase in human fetal livers: high similarity to placental form.

An acidic form of glutathione S-transferase (GST) was purified from human fetal livers by means of affinity chromatography and chromatofocusing. The major peak of the acidic form of GST was focused between pH 4.8 and 4.9. Judging by SDS-PAGE, the purified acidic GST was apparently homogeneous; the subunit molecular weight was estimated to be 23,000. The acidic GST catalyzed the conjugations of glutathione (GSH) with 1-chloro-2,4-dinitrobenzene (CDNB) and ethacrynic acid (EA). The immunochemical properties of the purified acidic GST were indistinguishable from those of human placental GST-pi. The N-terminal amino acid sequence of the acidic GST was identical with that of GST-pi from human placenta. The level of expression of the acidic form of GST was clearly different between human adult and fetal livers as examined on the levels of mRNA and protein.

Amino Acid Sequence↗
PubMed1991

The effects of pretransplant cyclosporine therapy on rats grafted with twelve-hour cold-stored livers--with special reference to reperfusion injury.

The effect of pretreatment with cyclosporine on liver preservation was studied using a rat liver transplant model. In a preliminary 1-week survival study, 59 liver transplants were performed. In group A, neither donors nor recipients were treated. In group B, the recipients were pretreated by a 3-day course of CsA (10 mg/kg/day p.o.), but the donors were untreated. In group C, the donor rats were pretreated for 3 days with the same doses of CsA as in group B, but the recipients were not treated. The donor livers in each group were stored for 12 hr at 4 degrees C with Eurocollins solution and transplanted to the recipients. The CsA pretreatment to recipients (group B) significantly improved 1-week survival (57.1%, 8/14, P less than 0.01 versus control group A; 0%, 0/14 or group C; 14.3%, 2/14). To study lipid peroxidation and morphology, 72 rat livers were studied in 9 groups. In summary, CsA pretreatment to recipients resulted in suppression of the increase in MDA levels and amelioration of endothelial injury after transplantation. On the other hand, donor pretreatment exerted dual effects on the grafts; it ameliorated endothelial injury after reperfusion, but its hepatotoxic action exacerbated hepatocellular damage during hypothermic storage. Our study suggests that CsA pretreatment, particularly to recipients, is beneficial in liver preservation for hepatic transplantation. The mechanisms are discussed with regard to ischemia/reperfusion injury to hepatic endothelium.

Animals↗
PubMed1991

Familial hypobetalipoproteinaemia complicated by cerebellar ataxia and steatocystoma multiplex.

A 55-year-old man with cerebellar ataxia and steatocystoma multiplex was found to have reduced serum concentrations of total cholesterol, betalipoprotein and apolipoprotein B. Computed tomography revealed atrophy of the cerebellum and brain stem. Of the six family members examined, four had hypobetalipoproteinaemia, and one had mild ataxia. Similar skin lesions were noted in five male relatives. This case represents a rare combination of familial hypobetalipoproteinaemia, cerebellar ataxia and steatocystoma multiplex.

Cerebellar Ataxia↗
PubMed1991

Toxicity and toxins of natural blooms and isolated strains of Microcystis spp. (Cyanobacteria) and improved procedure for purification of cultures.

All samples of cyanobacterial blooms collected from 1986 to 1989 from Lake Kasumigaura, Ibaraki Prefecture, Japan, were hepatotoxic. The 50% lethal doses (LD50s) of the blooms to mice ranged from 76 to 556 mg/kg of body weight. Sixty-eight Microcystis cell clones (67 Microcystis aeruginosa and 1 M. viridis) were isolated from the blooms. Twenty-three strains (including the M. viridis strain) were toxic. However, the ratio of toxic to nontoxic strains among the blooms varied (6 to 86%). Microcystins were examined in six toxic strains. Five toxic strains produced microcystin-RR, -YR, and -LR, with RR being the dominant toxin in these strains. Another strain produced 7-desmethylmicrocystin-LR and an unknown microcystin. This strain showed the highest toxicity. Establishment of axenic strains from the Microcystis cells exhibiting extracellularly mucilaginous materials was successful by using a combination of the agar plate technique and two-step centrifugation.

Animals↗
PubMed1991

Comparison of two O-serogrouping systems for mesophilic Aeromonas spp.

Two O-serogrouping systems for mesophilic Aeromonas spp., National Institute of Health, Tokyo, Japan, and National Institute of Public Health and Environmental Hygiene, Bilthoven, The Netherlands, containing 44 and 30 reference strains, respectively, were compared. Nine strains in each system were considered identical. Thirty-four unique strains were identified, and 22 strains of the two systems were in an a,b-a,c type of relationship to each corresponding O group.

Aeromonas↗
PubMed1991

Targeted and highly efficient gene transfer into CD4+ cells by a recombinant human immunodeficiency virus retroviral vector.

We have established a recombinant HIV gene transfer system based on transient expression of the HIV packaging functions and a recombinant vector genome in monkey kidney Cos cells. The recombinant HIV retroviral vector introduced the neoR gene into CD4+ cells with high efficiency, comparable to that achieved with the highest titer amphotropic murine recombinant retrovirus. Vector preparations were devoid of replication competent, infectious HIV. Gene transfer was dependent on CD4 expression, as shown by expression of the CD4 gene in HeLa cells, and could be inhibited by soluble CD4. This specific and efficient gene transfer system may be useful for development of gene therapy for which T cells are the desired targets.

CD4 Antigens↗
PubMed1991

Effect of diabetes mellitus on levels of atrial natriuretic hormone in plasma and the right atrium in the non-obese diabetic mouse.

Atrial natriuretic hormone (ANH) levels in plasma and the right atrium of non-obese diabetic mice in the decompensated diabetic state were investigated by radioimmunoassay and histological examination. Severely diabetic mice, with blood glucose levels over 33.6 mmol/l showed significantly higher hematocrit, plasma sodium and calculated plasma osmolarity than the age-matched normoglycemic mice. The plasma ANH levels in diabetic mice were significantly lower (17.5 pmol/l) than those in normoglycemic mice (43.6 pmol/l). The ANH concentrations in the right atrium were 26.6 mg/g protein in the diabetic and 11.2 mg/g protein in the normoglycemic mice. The right atrium in the diabetic mice showed much wider immunohistochemical staining by anti-human ANH antiserum compared with the normoglycemic mice. An increase in the number of atrial specific granules in the diabetic mice was observed by transmission and scanning electron microscopy. Morphometrical analysis indicated that the number of granules increased to more than twice that in the normoglycemic mice. These findings indicate that plasma ANH decreases in diabetic mice. The store of right atrial ANH may be increased to compensate for the marked dehydration in severe diabetes.

Animals↗
PubMed1991

Demonstration of connective tissue sheaths surrounding working myocardial cells and Purkinje cells of the sheep moderator band.

Morphological studies were carried out to delineate the characteristics of connective tissue sheaths surrounding working myocardial cells and Purkinje cells in the moderator band of adult sheep hearts, using a series of techniques including silver staining, immunohistochemistry, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). For SEM, tissue blocks were treated with 2N NaOH at room temperature to digest cellular elements. Individual working myocardial cells were ensheathed by thin argyrophil fibers (reticular fibers), while fascicles of 4-8 Purkinje cells (Purkinje strands) were encircled by rather thick reticular fibers. Some collagen fibers were located between masses of myocardial cells as well as between the Purkinje strands. Immunohistochemical analyses indicated that reticular fibers directly surrounding both myocardial cells and Purkinje strands showed moderately positive reactions for anti-type I collagen and intensely positive reactions for anti-type III collagen. Deserves particular note is that the three-dimensional architecture of the reticular sheaths varied widely at different places. The thin reticular sheaths surrounding each myocardial cell consisted of fibrils which were arranged in a coarse network and directed circularly along the long axis of cells. By contrast, the sheaths enclosing Purkinje strands were thicker, and their reticular fibrils were woven into a compact "felt-like" texture. The functional significance of these connective tissue sheaths is also discussed.

Animals↗
PubMed1991

[The correlation between pulse wave velocity and diabetic angiopathy].

Pulse wave velocity (PWV) of the aorta was measured in 40 patients with diabetes mellitus, in order to study the relation between PWV and diabetic angiopathy. The PWV was significantly faster in diabetic patients on oral hypoglycemic agents than in those on diet alone or on insulin. The PWV correlated significantly and positively with age, systolic blood pressure and urinary albumin index. The PWV significantly faster in diabetics with microalbuminuria than in those without this findings. It was concluded that PWV in addition to known risk factors such as elevated blood pressure, atherogenic abnormalities of plasma lipids and lipoproteins, and elevated blood glucose, may be a reliable index of diabetic micro- and macroangiopathy.

Aged↗
PubMed1991

Salmonella enterica subspecies diarizonae bacteremia in an infant with enteritis--a case report.

The septicemia caused by the Arizona group organism is rare and usually observed in adults with underlying diseases. In Korea, Salmonella infection is common, but a report of Arizona infection is unknown. We isolated S. entercia subsp. diarizonae from blood of a 6-month-old infant. The serovar was determined as 28:z10:-, a rare one in America. The isolate was susceptible to ampicillin, chloramphenicol, cotrimoxazole and others. The patient rapidly recovered with ampicillin and gentamicin therapy. Clinical laboratories should consider that the infection exists in Korea and should attempt to isolate and identify Arizona organism in certain patients.

Bacteremia↗