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Biomedical subjects

A Yoshida

Publications and source records attributed to A Yoshida.

At least 811 records · Page 45Linked to original sources
PubMed1989

[MR imaging of hepatocellular carcinoma following transcatheter hepatic chemo-embolization].

Transcatheter chemo-embolization (TCE) for hepatocellular carcinoma (HCC) was performed on 31 patients, and on 4 of the 31 patients, it was performed twice. The patients were examined by MR both before TCE and after TCE (1 week and 4-5 weeks respectively). On MR images, the change of the tumor signal intensity was classified into 3 groups. In group 1, (G1, 8 cases), obvious change of intensity was seen in the whole tumor. In group 2, (G2, 10 cases), it was seen in some parts of the tumor and in group 3, (G3, 17 cases), only a very slight change of intensity was seen in the whole tumor. In G1 and G2, the rate of AFP decrease was remarkable, but in G3, it was very slight. In G1 and G2, the change of the tumor signal intensity was divided into 2 types on a T2 weighted image. One, is the increase of the intensity, (6 cases). The other, is decrease of intensity, (12 cases). The former seemed to reflect the intra-tumoral hemorrhage accompanying tumor necrosis, the latter, seemed to reflect the coagulation necrosis. The ring of low and high intensity around the tumor appeared anew in 11 cases, and in 2 cases, it increased in size. These changes which have never been recognized on CT images, were thought to be a granulation tissue around the tumor. The influence of the accumulated lipiodol is slight for the change of intensity on the tumor.

Aged↗
PubMed1989

Study of cell kinetics in anaplastic thyroid carcinoma transplanted to nude mice.

The cell kinetics of the transplantable human anaplastic thyroid carcinoma were studied in athymic nude mice using bromodeoxyuridine (BrdU) pulse labeling. In order to estimate the cell cycle time in this study, the percent labeled mitosis curve was prepared with immunoperoxidase staining using monoclonal antibody to BrdU instead of 3[H]thymidine autoradiography. This technique was considered to be very useful because it can be done for a short term and can still be changed to the autoradiographic method. Comparing the results in this study with already reported data on various xenografts of human carcinomas in nude mice, the tumor doubling time (117.5 hr) and the cell cycle time (23.5 hr) were rather short, but the growth fraction (54%) and the cell loss factor (68%) were nearly equivalent to the median value. These findings suggest that the very rapid growth rate of this tumor was mainly due to the shortness of the cell cycle time.

Animals↗
PubMed1989

Genotype of alcohol dehydrogenase and aldehyde dehydrogenase loci in Japanese alcohol flushers and nonflushers.

A much higher incidence of alcohol flushing among Orientals in comparison to Caucasians, i.e., greater than 50% vs 5%-10%, has been attributed to racial differences in alcohol-metabolizing enzymes. A large majority of Orientals are "atypical" in alcohol dehydrogenase-2 locus (ADH2), and their livers exhibit significantly higher ADH activity than the livers of most Caucasians. Approximately 50% of Orientals lack the mitochondrial aldehyde dehydrogenase (ALDH2) activity, and elimination of acetaldehyde might be disturbed. We determined by means of hybridization of genomic DNA samples with allele specific oligonucleotide probes, genotypes of the ADH2 and ALDH2 loci in Japanese alcohol flushers and nonflushers. We found that all individuals with homozygous atypical ALDH2(2)/ALDH2(2) and most of those with heterozygous atypical ALDH1(2)/ALDH2(2) were alcohol flushers, while all subjects with homozygous usual ALDH1(2)/ALDH1(2) were nonflushers. Frequency of the atypical ADH2(2) was found to be higher in alcohol flushers than in nonflushers, but the statistical significance was not established in the sample size examined.

Alcohol Dehydrogenase↗
PubMed1989

The effect of alcohol on the vestibulo-ocular reflex and gaze regulation.

To clarify the effect of the temporary decline in cerebellar function on the vestibulo-ocular reflex (VOR) and gaze functions, we examined 12 normal adults under passive rotations before and after they drank alcohol at dosages of 0.43 and 0.65 g/kg. Whereas spatial gaze fixation was maintained accurately with 0.65 g/kg administration (0.06% blood alcohol level), gaze fixation on a head-fixed target and smooth pursuit were impaired by the higher dosage of 0.43 g/kg (0.03% blood alcohol). The magnitude of the alteration in the VOR gain after drinking was correlated significantly with the VOR gain before drinking: while small values were enhanced by drinking, large values were suppressed. The present study indicates that the VOR in the dark is regulated by the balance between the amplifying and suppressing forces controlled by the cerebellum.

Adult↗
PubMed1989

Microscopic intranasal decompression of the optic nerve.

We report our methods for using the surgical microscope to decompress the optic nerve intranasally and our results in five cases with optic nerve trauma, including a 7-year-old girl. Decompression seemed necessary in cases without canal fractures (four cases in the present report), since circular disturbances from edema may play a role in producing reversible visual impairments. The intranasal approach not only solved cosmetic problems associated with other techniques, but also provided better, less distorted views when compared with extranasal or transantral approaches. Microsurgery using a self-retaining retractor speculum resulted in improved visualization and reliable procedures during surgery. Since the operation does not impose a cosmetic or physical burden on patients, it can be done early when indicated to accelerate visual improvement following trauma.

Adolescent↗
PubMed1989

Prolonged exposure to a K-rich medium makes the rat mast cell membrane permeable to external calcium ions.

Rat mast cells, pretreated with a Ca-free, high KCl medium for more than 30 min, released histamine when subsequently exposed to a medium containing 0.1-2 mM Ca, despite the absence of voltage-dependent Ca channels. Morphological studies showed that high KCl-treated cells became swollen and that the addition of Ca caused degranulation (exocytosis). Ca-stimulated histamine release was inhibited when the high KCl treatment medium contained dinitrophenol and 2-deoxyglucose. The response to Ca was also observed when KCl in the treatment medium was replaced by RbCl, CsCl, KBr or KNO3. When the high K-treated cells were incubated with 0.5 mM 45Ca at 0-1 degree C, 45Ca uptake by these cells was much larger than that by untreated cells, suggesting that the membrane permeability to Ca of these cells is increased. Although prolonged (90 min) incubation of the cells with an isotonic KCl medium increased the rate of leakage of lactate dehydrogenase possibly reflecting extensive cell swelling, most cells recovered the ability of responding to stimulation with compound 48/80 or with simultaneous removal of Na and Ca when subsequently incubated with a Na-based medium containing Ca. Raising the KCl concentration above normal osmolarity in the treatment medium reduced the extents of cell swelling, without reducing the response to Ca addition. Under various other experimental conditions, a poor correlation was also found between the extents of swelling and the magnitude of the response to Ca. These results raised the possibility that intracellular accumulation of a particular species of anions increased membrane permeability to Ca.

Animals↗
PubMed1989

A case of metastasis from gastric cancer to the thyroid gland.

Metastatic tumors in the thyroid gland are rarely seen in clinical practice. This report describes a case of metastasis from gastric cancer to the thyroid, found five years after removal of the primary gastric lesion. The patient had a large thyroid mass extending to the mediastinum, but there were no obvious metastatic lesions anywhere except in the thyroid. Subtotal thyroidectomy was performed and histological examination revealed the same findings a those of the original gastric cancer. Of additional interest are the findings that led us to believe this metastatic tumor produced alpha-fetoprotein. Seven months following the operation, the patient dies suddenly and, although it is difficult to say whether the patient's survival was prolonged, we believe that the thyroid surgery gene him considerable palliation.

Adenocarcinoma↗
PubMed1989

Studies on age-related functional changes in regulatory T cells and B cells involved in the autoantibody production of MRL/MpJ- +/+ mice.

Age-related changes in anti-DNA autoantibody production of MRL/MpJ- +/+ mice were investigated. In lipopolysaccharide (LPS)-stimulated cultures, spleen cells of the mice showed an age-related, marked increase in the ability to produce IgG class of the autoantibody after the age of 12 months, while they showed a tendency to decrease with age in the production of IgM class of the autoantibody. Serum levels of anti-DNA autoantibodies rose markedly in the IgG autoantibody but not in the IgM autoantibody after 12 months of age, which is well consistent with the observation in the LPS-stimulated cultures. T cell-depleted spleen cells, however, showed only a small increase with age in the IgG autoantibody productive ability. These results suggest that the age-associated increase in the IgG autoantibody production in the mice is under T-cell control. Age-associated changes in suppressor capacity in spleen cells of the mice were also investigated. Suppressive activity of the cells stimulated by 2-day incubation with concanavalin A (Con A) showed a clear increase as the donor age advanced, when assayed on the LPS-stimulated anti-DNA autoantibody production in vitro. The results indicate that, in MRL/MpJ-+/+ mice, suppressor capacity does not decline with age and is not related as a cause to the autoantibody production.

Aging↗
PubMed1989

Effect of luteinizing hormone-releasing hormone on the mechanical activity of the guinea-pig cardiac muscle.

1. The inotropic effect of physiological concentrations of luteinizing hormone-releasing hormone (LH-RH) in isolated guinea-pig cardiac muscles was studied. 2. LH-RH increased the contractile force elicited by either fast and slow responses in a dose-dependent manner. 3. These effects of LH-RH were affected by phentolamine and diltiazem but not by propranolol and cold condition. 4. This study showed the positive inotropic effect of LH-RH on myocardium through the affection to intracellular Ca, and the difference from the effect of cardiotonic steroids.

Animals↗
PubMed1989

Genomic structure of the human cytosolic aldehyde dehydrogenase gene.

We have isolated and characterized several overlapping clones from two human genomic libraries constructed in cosmid and bacteriophage vectors. They span about 80 kbp and include the entire human cytosolic aldehyde dehydrogenase (ALDH1) gene. Restriction endonuclease mapping, Southern blotting with cDNA and specific oligonucleotide probes, and DNA sequencing were performed to analyze the cloned genomic DNA. The ALDH1 gene is about 53 kbp long and is divided into 13 exons which encode 501 amino acid residues. Primer extension results defined the transcription initiation site to 53 bp upstream from the A of the initiation codon ATG. The promoter region of the gene contains an ATA box and a CCAAT box, which are located 32 and 74 bp upstream, respectively, from the transcription initiation site. The possible functional domains of the protein encoded by exons are discussed. A similar intron-exon organization between the genes of cytosolic ALDH1 and its mitochondrial ALDH2 isozyme in which both enzymes are encoded by 13 exons and 9 of the 12 introns interrupt the coding sequence at homologous positions was observed. This is consistent with the model that the two isozyme genes evolved after the duplication of a common ancestor gene.

Aldehyde Dehydrogenase↗
PubMed1989

Chromosomal assignment of the alcohol dehydrogenase cluster locus to human chromosome 4q21-23 by in situ hybridization.

Human class I alcohol dehydrogenase (alcohol:NAD+ oxidoreductase, EC 1.1.1.1; ADH) is the major enzyme involved in ethanol oxidation. Three highly homologous genes govern the synthesis of three types of subunits which form several ADH isozymes. The locus for class I ADH loci was previously assigned to q21-25 of chromosome 4 by somatic cell hybridization techniques. Analysis of grain positions by in situ hybridization of chromosomes indicated that the ADH cluster locus is on 4q21-23, probably 4q22.

Alcohol Dehydrogenase↗
PubMed1989

Delayed activation of large-conductance Ca2+-activated K channels in hippocampal neurons of the rat.

We applied a fast concentration jump system to produce step changes in Ca2+ concentration [( Ca2+]i) on the cytoplasmic side of the inside-out membrane patch, excised from isolated rat hippocampal pyramidal neurons, and examined the time course of the activation phase of the large-conductance K channel (the BK channel; approximately 266 pS) after a step rise in [Ca2+]i. Diffusion of Ca2+ from the electrode tip to the cytoplasmic surface of the patch was estimated to be almost completed in 10 ms. After a step increase in [Ca2+]i from 0.04 to 3.2-1,000 microM, the activation of the K channel started after a clear latency of 280-18 ms and proceeded along a sigmoidal function. This was in sharp contrast with the rapid deactivation that began without delay and that was completed within 50 ms. The latency in activation was not accounted for by the binding of Ca2+ to EGTA in unstirred layers in the patch, since this binding was reported to be slow, taking up to seconds at physiological pH. Calmodulin (1 microM) did not affect the delay, the activation rate, or the steady-state current level. The calmodulin inhibitors W-7 and W-5 caused flickering of the single-channel current. These results indicate a delayed activation of the BK channel after a step rise in [Ca2+]i, suggesting that the BK current does not contribute to the repolarization of the action potential. Calmodulin is probably not involved in the activation process of the channel.

Animals↗
PubMed1989

Effect of dietary ascorbic acid, cholesterol and PCB on cholesterol and bile acid metabolism in a rat mutant unable to synthesize ascorbic acid.

The effect of acute or chronic ascorbic acid deficiency on the activity of hepatic cholesterol 7 alpha-hydroxylase and fecal excretion of bile acids was investigated in ODS-od/od (OD) rats (a rat mutant unable to synthesize ascorbic acid) fed a purified basal diet or purified diets containing either cholesterol (2%) or polychlorinated biphenyl (PCB) (200 mg/kg). In OD rats, the dietary requirement of ascorbic acid to maintain normal growth and normal levels of cholesterol in serum and liver is about 300 mg of ascorbic acid/kg diet. In OD rats fed the basal diet, acute or chronic ascorbic acid deficiency did not affect the activity of hepatic cholesterol 7 alpha-hydroxylase and fecal excretion of bile acids. However, in OD rats fed diets containing either cholesterol or PCB, acute ascorbic acid deficiency caused a higher level of serum cholesterol, a lower activity of hepatic cholesterol 7 alpha-hydroxylase and a lower excretion of fecal bile acids than in OD rats fed a basal diet containing an adequate level of ascrobic acid. It is concluded that acute ascorbic acid deficiency causes a hypercholesterolemia due to the depression of bile acid synthesis in OD rats fed a purified diet with cholesterol or PCB.

Animals↗
PubMed1989

Bi-directional regulation of dephosphorylation of cAMP-dependent phosphorylated proteins by cAMP and calcium in permeabilized rat heart cells.

We studied the regulation of dephosphorylation of cAMP-dependent phosphorylated proteins of isolated, permeabilized (skinned) myocardial cells from adult rat. Staurosporine, a potent inhibitor of protein kinase, inhibited cAMP-dependent phosphorylation of phospholamban and troponin-I, the key proteins in the control of contraction and relaxation of the myocardial cells. Staurosporine antagonized the stimulatory action of cAMP on the spontaneous beating of the myocytes accompanied by dephosphorylation of phospholamban but not of troponin-I at pCa 7-8. In cold ATP dilution experiments with apparent stoppage of protein phosphorylation, dephosphorylation of phospholamban was accelerated both by Ca2+ and staurosporine but that of troponin-I took place only in the presence of Ca2+ ion (pCa less than 6.5). These phenomena suggest a bi-directional regulation of dephosphorylation of the key proteins by the intracellular messengers cAMP and Ca2+.

Adenosine Triphosphate↗
PubMed1989

Cytosolic aldehyde dehydrogenase (ALDH1) variants found in alcohol flushers.

Although mitochondrial aldehyde dehydrogenase (ALDH2) has been thought to play a major role in acetaldehyde detoxification, and the high incidence of 'alcohol flushing' among Orientals is attributed to the inherited deficiency of ALDH2, the role of cytosolic aldehyde dehydrogenase (ALDH1) cannot be ignored. On the premise that alcohol flushing in Caucasians could be related to ALDH1 abnormalities, we examined the enzyme properties and electrophoretic mobilities of ALDH1 partially purified from red blood cells of nine unrelated alcohol flushers. One exhibited very low activity (10-20% of control level), and another exhibited moderately low activity (60%) and altered kinetic properties. The electrophoretic mobilities of these two samples were also distinguishable from the control samples. Immunological quantitation indicated that the amounts of ALDH1 protein in these two samples were not reduced in parallel with their enzyme deficiency. In the first case, the two characteristics, i.e. very low enzyme activity and alcohol flushing, were inherited by her daughter.

Alcoholic Intoxication↗
PubMed1989

[Epidemiological aspects of enteritis due to Campylobacter jejuni].

From September 1986 through July 1987, all fecal specimens obtained from infants and children who visited the pediatric clinic of the Shizuoka General Hospital with complaints of abdominal pain or diarrhea were examined for thermophilic Campylobacters. Bacteriological and epidemiological studies were performed on household contacts. The mothers of the patients were compared with the mothers of age-matched control subjects. Bacteriological examination of animals in 49 primary schools in Shizuoka city was performed. C. jejuni was isolated from 47 (9.4%) of the 499 feces samples, occupying first place in the bacterial etiology of acute bacterial enteritis. Infants and young children below 10 years of age comprised 81% of the total cases. Fourteen (13%) strains of C. jejuni were isolated in 9 families among 105 household contacts of the index patients. Six symptomatic contacts in two households had eaten the same suspected chicken as the respective index patients. In three families, C. jejuni was isolated from the remainder of the chicken. The serotype of these isolates was identical to that of the isolates from the index cases and the other family members. It was also noted that the same chopping boards were used for the preparation of salads after cleansing with water. In two index cases, the antibody of convalescent serum against C. jejuni isolated from the chicken, as estimated by passive hemagglutination method, ranged from 1:320 to 1:1280. These facts strongly supported the assumption that they had been infected by the chicken. The remaining persons were asymptomatic and the possibility was left that the index cases had been secondarily infected by these carrier persons.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Refractory anemia terminating in acute megakaryoblastic leukemia (M7).

A 72-year-old man with refractory anemia (RA) developed overt megakaryoblastic leukemia after the course of RA with excess of blasts. The blasts were positive for platelet peroxidase activity and had platelet glycoproteins (GPs) such as GPIIb/IIIa and GPIIIa. The bone marrow biopsy at terminal stage disclosed marked fibrosis. The nature of the megakaryoblasts was investigated. The blasts did not differentiate morphologically into mature megakaryocytes with TPA addition. In vitro colony assay showed the failure of colony-forming unit, megakaryocyte growth in peripheral blood. The pathogenesis of myelofibrosis in our patient is discussed.

Aged↗