Biomedical subjects

Y Tamura

Publications and source records attributed to Y Tamura.

At least 325 records · Page 18Linked to original sources

PubMed1994

Transformation-associated 86 kDa natural killer target molecule expressed on the mouse, rat and human cell surface.

We previously reported on the 86 kDa natural killer target molecule associated with transformation of the oncogene-transfected rat fibroblasts. This molecule may participate in the lethal hit phase of cytotoxicity by natural killer (NK) cells. Originally, this molecule was defined by mAb109, but mAb109 could react only with rat tumor lines. In this report, to determine whether the 86 kDa molecule could be utilized as a natural killer target molecule in mammalian cells, we developed a polyclonal anti-86 kDa antibody (pAb109). Our data indicated that pAb109 preferentially reacted with NK-susceptible lines such as mouse YAC-1, rat W31 and human K562 cells, but reacted only weakly with NK-resistant mouse EL-4, rat fetal fibroblast WFB and human fetal fibroblast HEPM. In a cytotoxicity experiment, pAb109 F(ab')2 fragments could inhibit the cytolysis by NK cells of W31 and K562 cells. However, these fragments did not inhibit the cytotoxicity of non-NK cells such as CD3+, CD4-, CD8- T cell receptor alpha beta- T cells (presumably gamma delta T cells) to W31 cells. Taken together, these data suggest that the cell transformation-associated 86 kDa molecule may be critical in NK cytotoxicity, and a candidate for the NK target structure in mammalian tumor cells.

3T3 Cells↗

PubMed1994

Gene screening in Japanese families with complete deficiency of thyroxine-binding globulin demonstrates that a nucleotide deletion at codon 352 may be a race specific mutation.

OBJECTIVE: Thyroxine-binding globulin (TBG) is a serum protein that transports 75% of circulating thyroxine. Eleven naturally occurring mutations in the human TBG gene have been identified, ten of which alter the properties of the molecule. Three of these mutations produce complete deficiency of TBG (TBG-CD) and four are associated with a second mutation in codon 283 (TBG-poly) which is polymorphic in some ethnic groups but, when present alone, does not alter the properties of the TBG molecule. In this communication we investigate whether two unrelated Japanese families with TBG-CD harboured the TBG-CDJ mutation in codon 352 associated with TBG-CD in families residing in more distant locations of the Japanese Islands. In addition we examined the possible association with TBG-poly and its incidence in the Japanese population. DESIGN: Mutant alleles were identified by amplification of genomic DNAs by the polymerase chain reaction, using allele-specific oligonucleotide primers. PATIENTS: Eight family members and 25 normal subjects. MEASUREMENTS: Serum free thyroxine and TBG concentration were measured by a conventional radioimmunoassay and a more sensitive enzyme immunoassay. Genomic DNAs were extracted from white blood cells and specific mutations at codons 352 and 283 were identified by allele-specific amplification. RESULTS: Three males and three females, whose serum TBG levels were decreased, had mutations at codon 352 as hemizygous and heterozygous, respectively. This mutation was not present in the DNA of any of the related or unrelated subjects with normal TBG concentration. The presence of TBG-poly was demonstrated in only one heterozygous family member and in six out of 30 alleles (20%) in normal unrelated subjects. The frequency of this TBG polymorphism in the Japanese is similar to that of 16% reported in French Canadians. CONCLUSIONS: We conclude that TBG-CDJ might be a prevalent cause of complete deficiency of thyroxine-binding globulin in the Japanese and that TBG-poly probably appeared before the divergence of human races.

Alleles↗

PubMed1994

Mixed tumor of the external auditory canal.

A mixed tumor with apocrine differentiation seen in the external auditory canal of a 39 year old male is reported. The well demarcated polypoid tumor showed proliferation of elongated gland-like or duct-like structures lined by two rows of epithelial cells, occasionally accompanied by foci of keratinization. There were fat cells in the myxoid stroma, in which no chondroid elements were seen. This neoplasm is considered to have arisen from the ceruminous gland, the modified apocrine gland of the skin.

Actins↗

PubMed1994

Protection of mice against Clostridium chauvoei infection by anti-idiotype antibody to a monoclonal antibody to flagella.

Polyclonal rabbit anti-idiotypic antibody (anti-Id) against the protective monoclonal antibody specific to the flagella of Clostridium chauvoei was produced, purified, and characterized. Anti-Id inhibited the binding of its related monoclonal antibody to the flagellar antigen, suggesting that the anti-Id bore an internal image of the flagellar antigen. When mice were immunized with anti-Id intraperitoneally, the survival rate increased significantly, compared with mice immunized with normal rabbit IgG (P < 0.01), and specific anti-flagellar antibodies were induced.

Animals↗

PubMed1994

Evidence that FK506 alleviates ischemia/reperfusion injury to the rat liver: in vivo demonstration for suppression of TNF-a production in response to endotoxemia.

The mechanism by which FK506 (FK) prevents hepatic injury induced by ischemia/reperfusion was studied. Adult Sprague-Dawley rats were subjected to 60-min normothermic liver ischemia. Animals were divided into two groups: group I, controls, saline vehicle treatment; group II, FK treatment. FK (1 mg/kg/day, p.o.) was given for 4 consecutive days prior to inducing ischemia. In addition to a survival study, plasma levels of endotoxin and serum activities of tumor necrosis factor-alpha (TNF) and aspartate aminotransferase (AST) were assessed in the blood collected from suprahepatic vena cava. Results showed: (1) FK therapy significantly improved 7-day survival (80.0%) compared with nontreated animals (50.0%, p < 0.05); (2) both TNF and endotoxin were elevated following reperfusion, reaching maximum values at 3 h after reperfusion (217.0 +/- 40.6 and 280.5 +/- 31.4 pg/ml, respectively, in the control; mean +/- SEM), and (3) serum activities of TNF and AST following reperfusion were substantially suppressed with FK treatment, whereas FK did not reduce the rise in endotoxin. These findings suggest that suppression of TNF production in response to endotoxemia might account at least in part for the protective effect of FK against ischemia-induced hepatic injury.

Animals↗

PubMed1994

Reduction of dental plaque deposition in humans by oolong tea extract.

The inhibitory effect of oolong tea extract (OTE) containing polymerized polyphenols on plaque deposition was examined in 35 human volunteers. Thirty-five human volunteers, aged 18-29 years, who received extensive oral prophylactic procedures were requested to refrain from all oral hygiene procedures for 4 days, and to rinse their mouth with 0.5 mg/ml OTE solution in 0.2% ethanol before and after every intake of food and before sleeping at night. No restriction regarding meals was given during the test period, except to refrain from teas or coffee. Plaque deposition was evaluated after disclosing the teeth with Erythrocin at the termination of this experiment. The study was repeated 1 week after the first trial, but only 0.2% ethanol without OTE was used for mouthrinsing in the second trial. OTE was found to significantly inhibit plaque deposition in volunteers, although mouthrinsing with OTE solution had no significant effect on the number of mutans streptococci in unstimulated whole saliva.

Adolescent↗

PubMed1994

Regulation of sterol carrier protein 2 (SCP2) gene expression in rat peritoneal macrophages during foam cell formation. A key role for free cholesterol content.

Sterol carrier protein 2 (SCP2) has been shown to be involved in intracellular transport and metabolism of cholesterol. However, there have been no reports concerning SCP2 in macrophages, the major source of atheromatous foam cells. We investigated whether SCP2 is present in rat peritoneal macrophages and determined the changes of SCP2 and its mRNA levels in macrophages during form cell formation induced by acetylated LDL (AcLDL). Immunoblot analysis and Northern blot analysis demonstrated that both SCP2 and its mRNA are expressed in rat peritoneal macrophages. Incubations with AcLDL caused a dose- and time-dependent increase of cellular esterified cholesterol, SCP2 and its mRNA in rat peritoneal macrophages. The inhibitor of acyl-CoA:cholesterol acyltransferase further enhanced AcLDL-induced increase of SCP2 protein and its mRNA. Incubations with 25-hydroxy cholesterol also caused a dose-dependent stimulation of SCP2 gene expression in macrophages, while incubation with maleylated BSA had no effect. These results suggest that the increment of cellular-free cholesterol is responsible for enhanced SCP2 gene expression in macrophages. The enhancement of SCP2 gene expression by AcLDL suggests that SCP2 may play an important role during foam cell formation induced by AcLDL which may be most important step for the atherosclerosis.

Albumins↗

PubMed1994

Characterization of guinea pig estrogen sulfotransferase expressed by Chinese hamster ovary cell-K1 stable transfectants.

Estrogen sulfotransferase (EST) activity expressed by Chinese hamster ovary (CHO)-K1 cells stably transfected with a plasmid containing a guinea pig EST complementary DNA insert was subjected to biochemical characterization, and the EST protein was further examined by nondenaturing isoelectric focusing and immunoblot analysis. CHO-K1 cells transfected with the same plasmid without the EST complementary DNA insert as well as untransfected CHO-K1 cells did not demonstrate either EST activity or the presence of an immunologically related protein. The EST expressed by the stably transfected CHO-K1 cells was found to manifest Michaelis-Menten kinetics and would use only estrogenic steroids as substrates, whereas other forms of steroids, such as pregnenolone, dehydroepiandrosterone, cortisol, and testosterone, were not acted on. When 17 beta-estradiol was used as a substrate, sulfonation occurred exclusively at the 3 position; 17-sulfonate was not formed. Thus, the expressed EST acted selectively on the 3-hydroxyl group of phenolic steroids. The apparent Km values for estrone, 17 beta-estradiol, and estriol were 60, 70, and 40 nM, respectively. The maximum velocity (Vmax) determinations for estrone and 17 beta-estradiol were equivalent, whereas the Vmax for estriol was reduced by 33%. Of the three estrogens, only 17 beta-estradiol caused substrate inhibition at a high concentration. Steroid sulfonation requires 3'-phosphoadenosine-5'-phosphosulfate (PAPS) as the active sulfonate donor, and the Km value for PAPS was 1.2 microM. In steroid sulfotransferase reactions, two products are formed: the sulfonated steroid product and the desulfonated cofactor, 3'-phosphoadenosine-5'-phosphate (PAP). The sulfonation of 17 beta-estradiol was inhibited by PAP in a dose-dependent manner. In addition, the Km for PAPS was increased by PAP, whereas the Vmax was unaffected, indicating competitive inhibition (Ki, approximately 0.52 microM). The EST protein expressed by the CHO-K1 cell stable transfectants demonstrated a mol wt of 34 kilodaltons, as determined by sodium dodecyl sulfate-gel electrophoresis. Additionally, when the expressed EST protein was subjected to isoelectric focusing, it was found to consist of multiple charge isoforms. These findings are comparable to what has been previously reported for native guinea pig adrenocortical EST. Furthermore, the charge isoform pattern that was demonstrated for the expressed EST was similar to the pattern observed for the native protein.

Adenosine Diphosphate↗

PubMed1994

Sweetness of glycyrrhetic acid 3-O-beta-D-monoglucuronide and the related glycosides.

To improve the taste profile of glycyrrhizin (1, the saponin of licorice root, relative sweetness to sucrose: x170), a variety of 3-O-glycosides of glycyrrhetic acid were prepared and their sweetness evaluated. It was found that a significant enhancement of sweetness was observed for the 3-O-beta-D-xyloside and the 3-O-beta-D-glucuronide (MGGR). Especially, MGGR had a high sweetness relative to sucrose; x941, and would appear to be a new potent sweetener.

Carbohydrate Sequence↗

PubMed1994

Evaluation of cancer prevention strategies by computerized simulation model: methodological issues.

A computerized simulation model developed to evaluate the potential impact of primary and secondary prevention is discussed from methodologic perspectives. In the simulation model, named CANSAVE (Cancer Strategy Analysis and Validation of Effect), the natural history of cancer was modeled as a Markovian stochastic process from cancer-free state to death. The lung cancer death rate among Japanese males was projected for 50 years to the year 2041. The simulation showed that the age-adjusted death rate would increase and reach a peak of 166 per 100,000 in 1989 and then decrease to 148 in 2003. It then shows a tendency to increase again, up to 255 in 2028. This change may be attributed to a lower smoking initiation rate among those born in the 1930s. Promotion of mass screening programs exhibits a more prompt effect than antismoking efforts, but the reduction in annual deaths is expected to be only 11%, even if a 100% participation is realized by the year 2000. The reduction in smoking initiation rate, on the other hand, begins to show a visible effect very slowly. It was predicted that a 1% annual reduction in smoking initiation rate would result in a 20% decrease in the number of deaths in 2041. The smoking cessation program is in the middle with regard to promptness. The predicted reductions in lung cancer deaths in 2041 were 13, 47, and 66%, respectively, when the annual smoking cessation rate was increased from 0.46% (present status) to 1, 3, and 5%. The combined application of all three preventive measures seems essential to realize the most effective reduction in lung cancer deaths.

Adult↗

PubMed1994

Cellular fatty acid composition of Erysipelothrix rhusiopathiae and Erysipelothrix tonsillarum.

The cellular fatty acid compositions in 6 strains of Erysipelothrix rhusiopathiae and 7 strains of Erysipelothrix tonsillarum were determined by gas chromatography. Fatty acids, ranging from C10 to C18, were detected in the test strains. The fatty acid profile was characterized by very high percentages of 18:1 (cis-9) (cis-9-octadecenoic acid; 72.4 to 82.1%) and 16:1 (hexadecenoic acid; 8.7 to 13.7%). The profiles of the E. rhusiopathiae and E. tonsillarum strains resembled each other, indicating that discrimination between E. rhusiopathiae and E. tonsillarum from qualitative or quantitative fatty acid differences is difficult.

Animals↗

PubMed1994

Clinical and angiographic characteristics of patients with multivessel coronary spasm in variant angina. Significance of progressive course of angina and disease activity.

The purpose of this study was to investigate the incidence of multivessel coronary spasm and compare the clinical characteristics between patients with and without multivessel coronary spasm. In variant angina, it is controversial whether coronary hyperreactivity to vasoconstrictor stimuli is localized to a segmental lesion in only one coronary artery. Moreover, the clinical characteristics of patients with multivessel coronary spasm have never been investigated. Sixty-three patients (51 men and 12 women; mean age, 56 years; range 35-72 years) with variant angina and documented ST-segment elevation during a spontaneous attack underwent spasm provocation testing with selective intracoronary injection of ergonovine. All but 4 patients who experienced spontaneous attacks during cardiac catheterization had induced coronary spasm associated with ST-segment elevation and chest pain. Multivessel coronary spasm was found in 27 (43%) of 63 patients. By univariate analysis, a high frequency of angina (> or = 3 times/week), occurrence of a spontaneous attack within 24 hours after withdrawal of medication, a long history of angina and a progressive course of angina were significantly associated with multivessel coronary spasm. Multivariate analysis indicated a positive correlation between multivessel coronary spasm and progressive angina. Multivessel coronary spasm was found in 43% of patients with variant angina. Patients with multivessel coronary spasm have some unique clinical features. These results may increase the understanding of the pathophysiology and natural course of variant angina.

Adult↗

PubMed1994

Intracoronary acetylcholine-induced prolongation of the QT interval and Torsade des Pointes in long QT interval syndrome.

A 75-year-old female had syncopal episodes from Torsade des Pointes (TdP). Her electrocardiogram showed a prolonged QT interval which was not associated with electrolyte imbalances or drug therapy. Similar electrocardiographic abnormalities were found in three family members. Electrophysiologic study showed a mildly prolonged effective refractory period of 260-290 msec, but no tachyarrhythmia was induced. Coronary arteriography was normal but intracoronary acetylcholine unexpectedly induced a prolongation of the QT interval and TdP. Direct action of acetylcholine on the ventricular muscle was suggested.

Acetylcholine↗

PubMed1994

Camptodactyly resulting from paradoxical action of an anomalous lumbrical muscle.

A 17 year old girl presented with camptodactyly resulting from an anomalous insertion of the lumbrical muscle into the flexor digitorum superficialis tendon. The fourth anomalous lumbrical muscle paradoxically caused flexion of the proximal interphalangeal (PIP) joint of the little finger when the patient extended the fingers fully. She was operated on, and the lumbrical tendon was cut at its insertion into the flexor digitorum superficialis tendon. The tight fascial band and skin contracture at the PIP joint were released, and the skin defect covered with a transposed flap. She made a good recovery and eight months after operation had only 40 degrees residual flexion deformity with full flexion of the PIP joint of the little finger.

Adolescent↗

PubMed1994

[Changes in fatty acid composition, platelet aggregability and RBC function in elderly subjects with administration of low-dose fish oil concentrate and comparison with younger subjects].

Anti-thrombotic and anti-atherogenic effects of eicosapentaenoic acid (EPA) through the modulation of various cell functions related to thrombogenesis have been reported recently. We previously reported that the administration of EPA at low doses could more effectively elevate the plasma EPA concentration in elderly subjects than in younger ones. Magnetic resonance imaging examination of the brain often reveals lacunar lesions in elderly subjects without any signs or symptoms of cerebrovascular diseases. In this study we clarified the effect of administration of low doses of fish oil concentrate on platelet and RBC function in elderly subjects, compared with younger subjects. Thirty six elderly subjects (mean age 78) without any signs or symptoms of cerebrovascular diseases, all receiving the same diet in the same lodging house for the aged, were divided into 3 groups. Different amounts of fish oil concentrate (0.25-0.5 g/day of EPA) were administered to the 3 groups, daily for more than 1 month. Changes of plasma fatty acid composition, platelet aggregability, whole blood viscosity and RBC deformability was examined before and after EPA administration. One month after EPA treatment, the plasma EPA content had increased dose dependently, with suppression of platelet aggregation and improvement of RBC function. In younger subjects receiving the same amount of EPA, the elevation of plasma EPA was less than that observed in the elderly. In summary, low dose EPA administration can improve the function of platelet and RBC to an anti-thrombotic state and would be useful to prevent the occurrence of cerebrovascular diseases in elderly subjects without any side effects.

Adult↗

PubMed1994

[Age-related changes of urinary collagen crosslinks and serum osteocalcin in postmenopausal women].

Urinary collagen crosslinks, lysyl pyridinoline (LP) and hydroxy lysyl pyridinoline (HL), have been shown to be specific parameters of bone degradation, while serum osteocalcin, referred to as bone Gla-protein (BGP), has been used as a sensitive marker of bone formation. The current cross-sectional study was designed to compare between pyridinoline contents in initial fasting urine and serum BGP in postmenopausal women aged 50-90 years. Both LP and HL increased by around 20% and BGP increased by nearly 30% in a later stage of menopause, indicating the possibility that bone turnover did not decline with age as far as could be assessed by these chemical markers. It was of interest that significant correlations of pyridinoline to BGP in the 50s and 60s (r = 0.52 - 0.60, p < 0.05) became insignificant after age 70. Although there is a limitation to these biochemical markers, the present data indicate that the coupling mechanism between bone resorption and formation may become inefficient with aging in postmenopausal women.

Age Factors↗

PubMed1994

[Analysis of epitopes for TSH receptor autoantibodies using TSH receptor/LH-CG receptor chimeras].

Graves' disease and idiopathic myxedema are autoimmune thyroid diseases and are caused by thyrotropin (TSH) receptor autoantibodies, thyroid stimulating antibody (TSAb) in Graves' disease and thyroid stimulation blocking antibody (TSBAb) in idiopathic myxedema. Studies with TSH receptor/lutropin-chorionic gonadotropin (LH-CG) receptor chimeras show that binding sites or epitopes on human TSH receptor for TSH, TSAb and TSBAb are different and, moreover, epitopes for TSAb are heterogeneous in different Graves' patients. Epitopes for TSAb exist in the N-terminal region and those for TSBAb in the C-terminal region on human TSH receptor extracellular domain.

Animals↗

PubMed1994

Angina-linked syncope and lack of calcium antagonist therapy predict cardiac arrest before definitive diagnosis of vasospastic angina.

BACKGROUND: Several prognostic factors have been identified in patients with vasospastic angina; however, factors that would predict potentially fatal cardiac arrest during the period between the onset of angina and its definitive diagnosis remain unknown. We investigated the predictive value of the clinical findings that are available when a patient is hospitalized after a cardiac arrest but before a definitive diagnosis of vasospastic angina is made. METHODS: We compared the clinical findings in 11 patients who experienced cardiac arrest before vasospastic angina was definitively diagnosed (group I) with 81 patients with vasospastic angina without cardiac arrest (group II). The definitive diagnosis of vasospastic angina was made on the basis of results of coronary spasm provocation test or ECGs during spontaneous attacks, or both. RESULTS: The incidence of angina-linked syncope was significantly higher in group I than in group II (six out of 11 versus nine out of 81, P < 0.005). Significantly fewer group I patients were receiving calcium antagonists than group II patients (three out of 11 versus 63 out of 81, P < 0.005). Serious arrhythmias were significantly more common in group 1 than in group II (seven out of 11 versus 12 out of 81, P < 0.005). Logistic regression analysis of the eight clinical variables available when first seen in the hospital indicated that angina-linked syncope and the lack of calcium antagonist therapy were independently related to risk of cardiac arrest. CONCLUSIONS: From the clinical findings available, a history of angina-linked syncope and lack of calcium antagonist therapy were found to be independent predictors of cardiac arrest before a definitive diagnosis had been made. Patients who have suspected vasospastic angina may benefit from early treatment with calcium antagonists if they have a history of angina-linked syncope.

Aged↗