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Y Tomita

Publications and source records attributed to Y Tomita.

At least 19 recordsLinked to original sources
PubMed1992

Effects of simulated left bundle branch block on QRST time-integral values of 12-lead electrocardiograms in patients with and without prior anterior wall myocardial infarction.

The effects of right ventricular pacing, which simulated left bundle branch block (BBB), on QRST time-integral values of 12-lead electrocardiograms (ECGs) were examined, and the clinical usefulness of QRST values for estimating the severity of left ventricular wall motion abnormalities due to a prior anterior wall myocardial infarction (MI) in the setting of left BBB were evaluated. Digitized ECGs were recorded during normal sinus rhythm and simulated left BBB in 38 patients (24 with and 14 without prior anterior wall MI). QRST values were calculated in each lead point of 12-lead ECGs. Data from 608 normal subjects were used as control values; the mean +/- 2 SD of these values was regarded as the normal range. The parameter sigma DE was defined as the sum of the differences between the normal mean QRST value and the QRST values of a given patient in leads where the QRST value was less than the normal range. The correlation coefficient of sigma DE for the 2 activation sequences was highly significant. Although small but significant changes were seen in QRST values in leads I, II, III, aVR, aVF and V1 during simulated left BBB, left precordial leads showed no significant changes in QRST values. A criterion of sigma DE > 40 mV.ms for detecting an anterior wall MI showed a sensitivity of 88%, a specificity of 93%, and a diagnostic accuracy of 89%. The sigma DE was significantly (p < 0.001) correlated with the asynergy index calculated from left ventriculograms.(ABSTRACT TRUNCATED AT 250 WORDS)

Bundle-Branch Block↗
PubMed1992

Identification of a cis-acting element that enhances the pigment cell-specific expression of the human tyrosinase gene.

To identify the cis-acting element that is responsible for the pigment cell-specific expression of the human tyrosinase gene, we analyzed the promoter activity of its 5'-flanking region by transient expression assays. The fusion genes were constructed by inserting the 5'-flanking region of the human tyrosinase gene upstream from the firefly luciferase gene and were introduced into human melanoma cells and HeLa cells. We thus found the element, located between 2.7 and 1.8 kilobase pairs upstream from the transcription initiation site, that enhances the transient expression of the luciferase reporter gene in melanoma cells, but not in HeLa cells, the tyrosinase gene expression of which is not detectable. Using the fusion genes containing putative enhancer elements under the control of the heterologous simian virus 40 promoter, we identified the pigment cell-specific enhancer of approximately 200 base pairs (bp) between -2.0 and -1.8 kilobase pairs and localized the core sequence to a 39-bp region. This 39-bp core element was then confirmed to direct the melanoma cell-specific expression of the reporter gene under the tyrosinase gene promoter. We thus propose that this core element is responsible for the pigment cell-specific expression of the human tyrosinase gene.

Animals↗
PubMed1992

Improved enzyme immunosorbent assay for mouse prolactin using penicillinase as label.

Enzyme immunosorbent assay (EIA) for mouse prolactin was established by modifying a method originally developed for human prolactin by Shrivastav et al. This simple, sensitive, rapid, and reproducible assay utilizes penicillinase as the labeling enzyme, rabbit anti-mouse prolactin antibody (Ab) and goat anti-rabbit Ig Ab as the first and second antibodies. Prolactin reference preparations and enzyme-conjugated prolactin were mixed with the first Ab and incubated for 0.5 h at 4 degrees C (24-48 h for serum samples). Then, the sample mixture was transferred to the wells of microtiter plate coated with the second Ab. After being kept at room temperature for 2 h, the plate was washed and filled with substrate solution (penicillin V). Absorbance at 620 nm was measured with an ELISA reader to quantitate the amount of conjugated prolactin bound to the second Ab. The prolactin levels obtained by this assay exhibited good correlation with those measured by radioimmunoassay (RIA) (y = 0.95x + 9.14, r = 0.943), and the sensitivity of EIA was equivalent to that of RIA (1.7 ng/ml). The CVs of intra-assay and inter-assay by EIA for mouse serum samples ranged comparably to those by RIA.

Aminoquinolines↗
PubMed1992

Downstream region of the human tyrosinase-related protein gene enhances its promoter activity.

We have cloned and sequenced the human genomic DNA segments encoding the 5'-flanking region and the first two exons of the tyrosinase-related protein (TRP) gene, a pigment cell-specific gene. Functional analysis of its promoter suggests that the downstream region of the TRP gene, including the first intron, enhances the transient expression of the luciferase gene under control of the TRP gene promoter about 16- to 20-fold. This enhancer-like activity is detected not only in melanoma cells but also in HeLa cells whose TRP gene expression is assumed to be repressed. We suggest a possibility that the downstream region is not sufficient to confer pigment cell-specific expression, but is required for efficient transcription of the TRP gene in pigment cells.

Animals↗
PubMed1992

Interaction of bovine serum albumin with the surface of a microcrystalline aluminum oxide hydroxide compound: a possible new type of phosphate adsorbent.

Aluminum hydroxide gel (ALG) has been effective for ameliorating acidosis associated with phosphatemia caused by hemodialysis. However, aluminum accumulation in the body causes severe side effects. As substitute for ALG, a new type of aluminum oxide hydroxide (tentatively named PT-A) was prepared with the hope of future clinical use. PT-A has a microcrystalline structure with a high resistance to pH change and has more phosphate-binding efficacy than ALG. It was tested for possible interaction with protein by adsorption test, zeta-potential analysis, X-ray diffraction, and scanning electron microscopy. Bovine serum albumin (BSA) was chosen as a model protein. The interaction of BSA with PT-A depended on the amount of adsorbent. Protein adsorption occurred rapidly and reached the maximal level at near neutral pHs. Phosphate adsorption was not affected by the presence of BSA, but the interaction of BSA with PT-A was significantly reduced by the presence of phosphate. Zeta-potential changes on the surface of PT-A indicated that the positively charged surface of PT-A was covered with negatively charged phosphate ions that repelled negatively charged BSA molecules. X-ray diffraction patterns indicated no observable structural alteration caused by adsorption of BSA or phosphate, and scanning electron microscopy revealed that BSA covered the outer surface of PT-A but did not cover small pores, where phosphate can freely penetrate.

Adsorption↗
PubMed1992

Interferon gamma but not tumor necrosis factor alpha decreases susceptibility of human renal cell cancer cell lines to lymphokine-activated killer cells.

Human renal cell cancer (RCC) cell lines, ACHN and KRC/Y, with or without exposure to cytokines, were examined for their susceptibility to lymphokine-activated killer (LAK) cells. Flow-cytometric analysis demonstrated constitutional expression of class I antigen on both cell lines, which was enhanced by interferon alpha (IFN alpha), IFN gamma and tumor necrosis factor alpha (TNF alpha). A 4-h 51Cr-release cytotoxicity assay demonstrated that pretreatment of both cell lines with IFN gamma or IFN alpha, but not with TNF alpha, decreased their susceptibility to LAK cells. IFN gamma also decreased susceptibility to natural killer cells in a 16-h 51Cr-release cytotoxicity assay. IFN gamma treatment decreased the susceptibility of ACHN cells in a dose-dependent manner. "Cold"-target competition assay clearly showed that IFN gamma- but not TNF alpha-pretreated cells compete less effectively than do untreated target cells. Pretreatment with IFN gamma, however, increased expression of intercellular adhesion molecule-1 (ICAM-1) to a degree comparable to that with TNF alpha. Northern blot analyses using a 520-base-pair ICAM-1 cDNA as a probe demonstrated that more 3.3-kb mRNA is expressed in IFN gamma- and TNF alpha-pretreated cells. These results suggest that IFN gamma-treated RCC cell lines may reduce their ability to be recognized by LAK cells, and that IFN-induced protection of RCC cell lines against LAK cells may depend upon a mechanism independent of the expression of class I antigens or ICAM-1 on tumor cells.

Carcinoma, Renal Cell↗
PubMed1992

Amplification and overexpression of the c-erbB-2 protooncogene in human gastric cancer.

The c-erbB-2 protooncogene encodes a possible growth factor receptor. This gene has been studied as to whether it can be regarded as a prognostic indicator in human breast carcinoma. As amplification and overexpression of the gene have been reported in several adenocarcinomas, 24 specimens of human gastric cancers were examined by immunohistochemical staining (24 cases), by Southern blotting (23/24) and by Northern blotting (16/24). Amplification of the gene was detected in two moderately differentiated tubular adenocarcinomas (8.7%), and overexpression of c-erbB-2 mRNA was detected in three moderately differentiated tubular adenocarcinomas (18.8%). By immunohistochemical staining of paraffin-embedded tissues using a polyclonal antibody to c-erbB-2 gene products, the cell membrane was stained positively in three cases of gastric cancers which overexpressed c-erbB-2 mRNA. Peritoneal metastases were found in six gastric cancers, including two moderately differentiated tubular adenocarcinomas in which amplification of c-erbB-2 occurred. These results suggest that amplification and overexpression of c-erbB-2 may be correlated with metastases in differentiated adenocarcinoma of the stomach.

Adenocarcinoma↗
PubMed1992

Alloreactivity against IE-encoded antigens: evidence of the discrepancy between graft rejection and reactivity of IE-reactive T cells.

Participation of IE antigens (Ag) in immune response as the transplantation Ag was examined. IE- B10.A(4R)(4R; Kk, IAk, IE-, Db) mice could not reject skin graft from IE Ag alone-disparate B10.A(2R) (2R; Kk, IAk, IEk, Db) mice despite intravenous (iv) injection of 2R spleen cells (SC) before or after skin grafting, indicating that graft rejection could not be caused across IE Ag-barrier alone. Furthermore, 4R SC could not induce lethal graft-versus-host disease (GVHD) in supralethally (950 rad) irradiated 2R mice. On the other hand, infiltration of lymphoid cells was observed at the site of transplanted 2R skin in 4R mice. SC of 4R mice unprimed or primed with 2R skin or 2R SC showed the capability to proliferate in vitro in response to 2R Ag. In immunofluorescence analysis of lymph node cells (LNC) of 4R mice injected iv with 2R SC 7 days earlier, IE-reactive CD4+Vbeta 11+ T cells did not change in number, but slightly increased the expression of interleukin-2 receptor (IL-2R). In 2R mice irradiated with 670 rad and injected iv with 4R SC 7 days earlier, 4R-derived CD4+V beta 11+ T cells proliferated, changed to blastoid form, and showed a markedly increased expression of IL-2R. To further investigate the influence of IE alloantigens on transplantation immunity, IL-2 production and anti-class I CTL activity were assayed. The 4R SC capable of recognizing IEk and Dk Ag of B10.BR (Kk, IAk, IEk, Dk) generated levels of both IL-2 and CTL activities higher than those of 2R SC capable of recognizing Dk Ag alone. These results strongly suggest that IE alloantigens indirectly act as the transplantation Ag by the stimulation of IE-reactive CD4+ helper T cells resulting in the differentiation of class I-restricted CD8+ T cells.

Animals↗
PubMed1992

Relationship of QRST isointegral maps during simulated left bundle branch block to impairment of left ventricular function due to myocardial infarction.

The clinical usefulness of QRST isointegral maps for assessing left ventricular (LV) dysfunction due to myocardial infarction (MI) in patients with MI in the setting of simulated left bundle branch block (LBBB) was investigated. Isointegral maps were recorded during sinus rhythm and right ventricular pacing, which simulated LBBB, in 62 patients with MI and 26 patients without MI. An abnormal decrease in the QRST value in the isointegral map was assessed by the difference map that indicated a "-2 SD area" where the QRST integral value was less than the normal range (mean - 2 SD) calculated from 608 normal individuals. The isointegral maps during the two activation sequences were similar in patients with and without MI (r = 0.87 and 0.92, respectively). The sum of QRST integral values less than the normal range (sigma DM) during simulated LBBB correlated significantly with the asynergy index, derived from left ventriculographic data (r = 0.81, p < 0.01). LV dysfunction (asynergy index > or = 2) was diagnosed in simulated LBBB with a sensitivity of 81%, specificity of 77%, and diagnostic accuracy of 80% when the criterion that LV dysfunction is present if the number of lead points in the -2 SD area exceeds 4, and a sensitivity of 71%, specificity of 81%, and diagnostic accuracy of 74% if sigma DM exceeds 200 mVms was used. The findings demonstrate that isointegral maps may be useful in assessing LV dysfunction due to MI in patients with MI and LBBB in addition to detecting the presence and site of MI in these patients.

Adult↗
PubMed1992

Small differences among body surface and epicardial QRST integral maps recorded during normal activation and experimentally simulated left bundle branch block or preexcitation in canine hearts.

QRST integral maps were constructed from 87-lead body surface electrocardiograms (ECGs) and from 45-lead epicardial electrograms during artificial pacing, which simulated left bundle branch block (LBBB) and Wolff-Parkinson-White syndrome in 12 dogs. Although the ECGs and electrograms differed in configuration for each conduction model, the body surface and the epicardial QRST integral maps showed only small differences. Correlation coefficients (r) and root mean square differences (rms) were calculated to assess quantitatively the similarities in the QRST integral maps among the different conduction models. Mean r values between the normal conduction and the left bundle branch block models were 0.95 in the body surface maps and 0.89 in the epicardial maps. Mean r values between the normal conduction and the Wolff-Parkinson-White ECG models were 0.97 in the body surface maps and 0.91 in the epicardial maps, and rms values were small enough. The small differences were also verified by the difference maps and by paired t tests. QRST integral maps on the epicardium and on the body surface were largely independent of altered activation sequences in both the left bundle branch block and the Wolff-Parkinson-White ECG models.

Animals↗
PubMed1992

Effects of various fat sources on growth and hepatic mitochondrial function in mice.

1. Five parameters with biophysical meaning for Parks' feeding and growth equations showed that mice fed diets containing hydrogenated beef tallow or beef tallow had lower mature body weight than soybean oil, linseed oil or fish oil-fed groups, and that mice fed hydrogenated beef tallow or fish oil diets had a lower feed efficiency factor than beef tallow, soybean oil or linseed oil-fed groups. 2. Mice fed the diet containing soybean oil or linseed oil had higher carcass fat as a per cent of body weight, significantly different from mice fed hydrogenated beef tallow, which exhibited the lowest carcass fat. 3. The respiratory rate of state 3 and the rate of ATP synthesis of liver mitochondria isolated were highest in the group fed the diet containing soybean oil.

Animals↗
PubMed1992

Cloning and sequence analysis of the tyrosinase gene from a patient with tyrosinase-positive oculocutaneous albinism.

Tyrosinase is synthesized on membrane-bound ribosomes and transported into melanosomes through smooth endoplasmic reticulum and Golgi apparatus. Melanin polymers are produced only in melanosomes but never in smooth endoplasmic reticulum or Golgi apparatus, indicating that posttranslational modifications of tyrosinase are completed with melanosomes where tyrosinase becomes an active form. Based on a working hypothesis that tyrosinase-positive oculocutaneous albinism is a consequence of the structurally altered tyrosinase due to a point mutation in the gene of its gene coding for a glycosylation site or a membrane-binding site, which leads to the impairment in the posttranslational modification of tyrosinase and its catalytic activity, we have cloned the tyrosinase gene of one patient affected with tyrosinase-positive oculocutaneous albinism and determined its nucleotide sequence. Thus demonstrated all exons' nucleotide sequence of the patient's tyrosinase gene was found to be identical to that of the wild-type gene. The results indicate that the patient's tyrosinase itself is not altered. We therefore propose that the molecular basis for the development of tyrosinase-positive oculocutaneous albinism exists as a defect in other proteins required for the activation of tyrosinase or in other regions of the tyrosinase gene.

Adult↗
PubMed1992

Bannayan-Zonana syndrome associated with lipomas, hemangiomas, and lymphangiomas.

Bannayan-Zonana syndrome is a rare disorder characterized by macrocephaly and multiple soft tissue and visceral hamartomas. This report presents a sporadic patient with macrocephaly, lipomas, hemangiomas, and lymphangiomas who died of cardiac and respiratory failure due to progressive cervicomediastinal arteriovenous fistulous hemangiomas at the age of 9 years.

Abnormalities, Multiple↗
PubMed1992

Comparison of tolerance inducibility to class I or class II antigens between cyclophosphamide (CP)-induced tolerance and transfusion with donor cells: general effectiveness of CP-induced tolerance and difference of skin graft prolongation in each class I antigen-disparate combination.

Transfusion with allogeneic cells alone was reported to prolong skin allograft survival in the MHC class I antigen alone-disparate combination of B6.C-H-2bm1 (bm1; Kbm1, IAb, IE-, Db)-->C57BL/6 CrSlc (B6; H-2b). Using 6 class I antigen-disparate and 2 class II antigen-disparate combinations, we compared the effectiveness for skin graft prolongation between transfusion with donor cells (TDC) and our system of CP-induced tolerance, which comprises intravenous (i.v.) injection of allogeneic cells followed by cyclophosphamide (CP), i.e., TDC followed by CP. TDC was effective only in the combination of bm1-->B6, but not at all in the other combinations. On the other hand, CP-induced tolerance was effective in the 5 class I antigen-disparate and 2 class II antigen-disparate combinations except for bm1-->B6 combination. These results suggest that CP-induced tolerance may be more general for the induction of unresponsiveness than TDC.

Animals↗
PubMed1992

Congenital caudal spinal atrophy: a case report.

An infant presented at birth with symmetrical flaccid paraparesis limited to lower legs and feet, and involving the proximal and distal muscle group. Limitation of the ankle joints was noticed. There were no sensory deficits to painful stimuli and no evidence of loss of sphincter control. Muscle CT revealed severe muscle atrophy in the pelvis and lower limbs, and electromyographic study of the bilateral hamstrings showed polyphasic giant potentials. Motor and sensory nerve conduction velocities were within normal limits, and the spinal MRI showed no structural abnormalities in the cord and the lower spine. These features suggest a congenital segmental abnormality at the anterior horn cell level in the lumbosacral spinal cord, which we propose to call "congenital caudal spinal atrophy".

Arthrogryposis↗
PubMed1992

Dietary protein level alters oxidative phosphorylation in heart and liver mitochondria of chicks.

To determine the effects of dietary protein level on cardiac and hepatic mitochondrial oxidative phosphorylation, chicks were fed on semi-purified diets of different protein levels (7, 25, 43 and 61% of metabolizable energy content) for 7, 14 and 21 d. All diets were formulated to contain equivalent fat, mineral and vitamin contents on a gross energy basis. Cardiac and hepatic mitochondrial oxidative phosphorylation rates were assessed polarographically with pyruvate and malate as substrates. Cardiac mitochondria isolated from chicks fed on a 43 or 61% protein-energy diet for 7 d exhibited significantly reduced ADP:oxygen (ADP:O) ratios when compared with mitochondria isolated from chicks fed on a lower-protein-energy diet. Feeding low- (7%) protein-energy diets for 14 d resulted in a relatively increased ADP:O ratio in the heart. Responses of ADP:O ratios to protein level in hepatic mitochondria showed more dependency on protein level than in heart muscle; at all feeding periods the ADP:O ratio decreased with an increase in protein level. As a result, ATP synthesized in the liver, expressed as nmol/mg mitochondrial protein per min, significantly decreased with increased dietary protein level. A parallel correlation was observed, in chicks fed on diets with different levels of protein, between ADP:O ratio for liver mitochondria and body fat. These results suggest that the reduction in oxidative phosphorylation in the heart and liver of animals fed on a higher protein-energy diet may partly contribute to the depression of body fat.

Adenosine Diphosphate↗
PubMed1992

Mechanisms of cyclophosphamide-induced tolerance to IE-encoded alloantigens--evidence of clonal deletion in MHC antigen-reactive cells for skin allograft rejection.

Transplantation tolerance across H-2D plus IE antigen barriers has been achieved when B10.Thy1.1 (Kb, IAb, IE-, Db; Thy1.1) mice were primed i.v. with 9 x 10(7) spleen cells plus 3 x 10(7) bone marrow cells from B10.A(5R) (Kb, IAb, IEb, Dd; Thy1.2) and treated i.p. with 200 mg/kg of cyclophosphamide (CP) two days later. The tolerant state was confirmed by prolonged acceptance of donor-type skin grafts, and in vitro unresponsiveness to donor antigens. From the early stage of tolerant state, V beta 11+ or V beta 5+ T cells expressing CD4 or CD8 accessory molecules were markedly decreased in the periphery of the tolerant mice. Moreover, neither CD4+CD8- nor CD4-CD8+ thymocytes bearing a high density of V beta 11 or V beta 5 were detected in the chimeric thymus. The intrathymic clonal deletion appeared to be maintained in some of the recipient mice even after the disappearance of detectable mixed chimerism in the late stage. These results suggest that the mechanisms of the CP-induced tolerance include the destruction of the IE (and probably H-2D) reactive T cells in the periphery followed by the intrathymic clonal deletion of T cells reactive against these antigens. These results directly show the strong correlation between transplantation tolerance to H-2 alloantigens and the disappearance of alloreactive T cells in both the periphery and thymus.

Animals↗