Biomedical subjects

Y Maeda

Publications and source records attributed to Y Maeda.

At least 523 records · Page 29Linked to original sources

PubMed1994

Detection of HCV RNA in subjects with antibody to hepatitis C virus among the general population of Fukuoka, Japan.

Volunteer blood donors and aged people who came to hospitals for a thorough physical checkup were surveyed to evaluate the exact prevalence of hepatitis C virus (HCV) infection in the general population of Fukuoka, Japan. We tested for antibody to HCV (anti-HCV) by second-generation assay and, to distinguish active HCV infection from past resolved infection, we tested for HCV RNA in reactive serum samples by polymerase chain reaction. The prevalence of anti-HCV was 286 (2.0%) of 14,341 subjects, increasing with advancing age, from 0.4% in the under-29 age group to 12.0% in the over-70 age group. There were no differences between sexes. HCV RNA was detected in 170 of 286 (59.4%) anti-HCV-positive subjects. The ratio of HCV RNA-positive to anti-HCV-positive subjects was higher in males than in females (P < 0.05) and decreased with advancing age, from 72.2% to 46.5%. The prevalence of elevated alanine aminotransferase (ALT) was only 15.9% in subjects with HCV RNA, higher in males (21.4%) than in females (8.3%) (P < 0.05). This study revealed that the prevalence of anti-HCV was high in the aged population, but that the ratio of HCV RNA-positive to anti-HCV-positive subjects was low, and most of the HCV RNA-positive subjects had normal ALT levels.

Adult↗

PubMed1994

Absence of hemodynamic tolerance to nicorandil in patients with severe congestive heart failure.

To evaluate whether hemodynamic tolerance develops to nicorandil, a nitrate and potassium channel opener, 14 patients with chronic heart failure (CHF) were treated with nicorandil and 11 were treated with nitroglycerin (GTN). Doses of GTN or nicorandil were titrated to achieve a > or = 20% reduction in pulmonary capillary wedge pressure (PCWP) within 1 hour, and the infusion was maintained at a constant rate for 24 hours. Both groups of patients had comparable hemodynamic parameters before drug infusions were started. The fall in PCWP was identical after 1 hour infusion of either GTN or nicorandil. In the GTN group, PCWP was not significantly different from the baseline value at 12 hours; however, in the nicorandil group, PCWP remained significantly lower than the preinfusion value for 24 hours. During the study period changes in plasma atrial natriuretic peptide (ANP) concentrations paralleled and correlated with changes in PCWP (r = 0.84, p < 0.001). These findings indicate that CHF patients develop hemodynamic tolerance to GTN within 12 hours of continuous infusion, but not to nicorandil, which remained hemodynamically effective during the 24-hour period of infusion. Furthermore, plasma ANP concentration may be a useful noninvasive index of hemodynamic tolerance during GTN or nicorandil therapy in patients with CHF.

Adult↗

PubMed1994

Impaired ketogenesis in patients with adult-type citrullinemia.

BACKGROUND/AIMS: To clarify the mechanism causing fatty liver in adult-type citrullinemia, the effect of fasting on blood levels of free fatty acids, triglycerides, and ketone bodies was investigated in two cases. METHODS: Blood and urine samples were collected from two patients and healthy volunteers 12, 15, 17, 21.5, and 24 hours after their last meal. RESULTS: During 24-hour fasting free fatty acid concentrations increased in both cases to the concentrations found in the healthy volunteers. The levels of blood ketone bodies (beta-hydroxybutyrate and acetoacetate) were markedly suppressed throughout the fasting test without any increase in urinary excretion of ketone bodies or organic acids in both cases when plasma citrulline concentrations were more than 10-fold higher than in controls. Serum triglyceride concentrations in case 1 paradoxically increased from 185 mg/dL to 294 mg/dL during 24-hour fasting when the citrulline concentration was extremely high. When hemodialysis was performed and plasma citrulline consequently decreased to near the normal level in case 1, levels of both serum triglycerides and blood ketone bodies responded normally to 24-hour fasting. CONCLUSIONS: These data suggest that ketogenesis was impaired in adult-type citrullinemia.

Adult↗

PubMed1994

Allolymphocytotoxic antibodies in sera from HTLV-I-associated myelopathy/tropical spastic paraparesis patients--putative anti-HLA antibodies.

Thirty-one HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients and 34 asymptomatic carriers were studied in order to investigate the presence of anti-lymphocyte antibodies in their sera. 32% of the patients produced allolymphocytotoxic antibodies reactive to peripheral blood lymphocytes (mainly T cells) as well as to B cells, which belonged to the IgM class, reacted under warm and cold conditions, and showed specificity to multiple HLA antigens, especially HLA A2, A26, A33, B7, B27, B35, B48, B61 and Cw3. Moreover, their reactivities could be absorbed by pooled platelets. Therefore, it may be suggested that either anti-HLA class I antibodies or antibodies cross-reactive to HLA were present. On Western blot analysis, the HAM/TSP cytotoxic sera reacted to the 110 kDa molecules of lymphocyte lysates. In the case of carriers, weak cytotoxic antibodies were detectable in 14% of the sera. No multispecificity to HLA class I antigens was observed and there was no reactivity to the 110 kDa band. The production of allolymphocytotoxic antibodies in HAM/TSP patients may therefore be explained by the presence of allogeneic-like stimuli in this disease. HTLV-I infected cells, expressing altered HLA antigens could possibly account for this stimulation and also contribute to the alteration of immune functions in HAM/TSP, and thus play an important role in its pathogenesis.

Adult↗

PubMed1994

Relation between endothelin-1 spillover in the lungs and pulmonary vascular resistance in patients with chronic heart failure.

OBJECTIVES: The aim of this study was to clarify the origin of plasma endothelin-1 and to determine the relation between pulmonary vascular resistance and endothelin-1 secretion in the pulmonary circulation in patients with chronic congestive heart failure. BACKGROUND: Plasma levels of endothelin-1, a potent endothelium-derived vasoconstrictor peptide, are increased in congestive heart failure, but the source has not been clarified. Recent studies have indicated a relation between endothelin-1 and pulmonary hypertension. We therefore evaluated the contribution of endothelin-1 secretion in the pulmonary circulation to the regulation of pulmonary vascular resistance in patients with chronic heart failure. METHODS: A comparison was made of the plasma levels of endothelin-1 between the main pulmonary artery and the pulmonary capillary wedge region, as well as between the femoral artery and the femoral vein in 62 patients with chronic heart failure. Stepwise multivariate regression analysis was used to detect independent predictors of pulmonary vascular resistance among the various vasoconstrictor hormones in these patients. RESULTS: There was no significant difference in plasma endothelin-1 levels between the femoral artery and vein. In contrast, plasma endothelin-1 increased significantly from the main pulmonary artery to the pulmonary capillary wedge region ([mean +/- SEM] 3.1 +/- 0.23 vs. 4.6 +/- 0.36 pg/ml, p < 0.01), and the increase was related to the severity of heart failure. Among the various vasoconstrictor factors, such as plasma active renin concentration, plasma angiotensin II, plasma norepinephrine, femoral venous plasma endothelin-1 and pulmonary endothelin-1 spillover, only endothelin-1 spillover in the lungs showed an independent and significant correlation with pulmonary vascular resistance (r = 0.82, p < 0.001). CONCLUSIONS: The main source of circulating endothelin-1 is not the peripheral vascular bed but the pulmonary vascular bed in patients with chronic heart failure. In addition, endothelin-1 secretion in the lungs may regulate the pulmonary vascular resistance in patients with chronic heart failure. These findings are consistent with a significant role for endogenous endothelin-1 in the pathophysiology of heart failure, especially in the pulmonary circulation.

Adult↗

PubMed1994

Inverse correlation between the titre of antibody to hepatitis C virus and the degree of hepatitis C viraemia.

We titrated 277 hepatitis C virus (HCV) antibody-positive serum samples from 235 volunteer blood donors as well as from 42 outpatients of a hospital for elderly people and studied the relation of the titre of HCV antibody to the presence of HCV RNA, of antibody to C100 protein (anti-c100) and of antibody to GOR epitope (anti-GOR). Liver dysfunction was measured also. Of 177 HCV RNA-positive serum samples, 87 were tested for the degree of HCV viraemia by means of a competitive assay. Among the 277 samples, prevalences of HCV RNA, anti-c100, anti-GOR and liver dysfunction were 63.9%, 71.8%, 75.7% and 17.5%, respectively. The prevalence of HCV RNA became higher as the titre of HCV antibody increased. The titre tended to increase with age but the tendency was not statistically significant. The mean titre was higher in females (2(10.4 +/- 1.8)) than in males (2(9.4 +/- 2.2)) (P < 0.01). In the HCV RNA-positive serum samples, the HCV antibody titre was significantly higher in the anti-c100-positive samples than in the negative ones. This difference between the positive and negative samples, however, was not statistically significant for anti-GOR and liver dysfunction. Low degrees of HCV viraemia were accompanied by high titres of HCV antibody while high degrees of HCV viraemia went with low titres of HCV antibody. The study revealed that titres of HCV antibody were higher in females and the degree of HCV viraemia correlated inversely with the titre of HCV antibody.

Adolescent↗

PubMed1994

Determination of trace amounts of urea by using flow injection with chemiluminescence detection.

Reaction between urea and hypobromite in alkaline solution was found to produce chemiluminescence with a maximum wavelength at 510 nm. A simple chemiluminescence detection method was used for the determination of urea in human urine and natural aqueous samples, which combined this chemiluminescence reaction with a flow injection analysis system. The relative standard deviation for 5 x 10(-7) mol dm-3 urea is 1.9% (n = 6), and the detection limit is 9.0 x 10(-8) mol dm-3 (3Sr). As this chemiluminescence reaction is very fast, a double concentric tube mixer connected directly to the chemiluminescence cell was used to mix urea solution and hypobromite solution. Alkylamines, carboxylic acids and most amino acids do not interfere in the determination. Ammonium ion interferes, but the sensitivity for ammonium ion is only 1% of that for urea. The interference from ammonium ion was removed sufficiently by using an on-line cation-exchange column.

Flow Injection Analysis↗

PubMed1994

Metabolic and biosynthetic alterations in cultured astrocytes exposed to hypoxia/reoxygenation.

To investigate the astrocyte response to hypoxia/reoxygenation, as a model relevant to the pathogenesis of ischemic injury, cultured rat astrocytes were exposed to hypoxia. On restoration of astrocytes to normoxia, there was a dramatic increase in protein synthesis within 3 h, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of metabolically labeled astrocyte lysates showed multiple induced bands on fluorograms. Levels of cellular ATP declined during the first 3 h of reoxygenation and the concentration of AMP increased to approximately 3.6 nmol/mg of protein within 1 h of reoxygenation. Reoxygenated astrocytes generated oxygen free radicals early after replacement into ambient air, and addition of diphenyliodonium, an NADPH oxidase inhibitor, diminished the generation of free radicals as well as the induction of several bands on fluorogram. Although addition of cycloheximide on reoxygenation resulted in inhibition of both astrocyte protein synthesis and accumulation of cellular AMP, it caused cell death within 6 h, suggesting the importance of protein synthesis in adaptation of hypoxic astrocytes to reoxygenation. Potential physiologic significance of biosynthetic products of astrocytes in hypoxia/reoxygenation was suggested by the recovery of glutamate uptake. These results indicate that the astrocyte response to hypoxia/reoxygenation includes generation of oxygen free radicals and de novo synthesis of products that influence cell viability and function in ischemia.

Adenosine Monophosphate↗

PubMed1994

Comparison of energy metabolism during the growing period in quail lines selected for body weight.

1. The present study was conducted to compare body weight, daily weight gain, relative growth rate, food intake, food conversion efficiency, abdominal fat weight, thyroid weight, plasma T4 concentration, body temperature, oxygen consumption, carbon dioxide production and heat production among three Japanese-quail lines selected for body weight: a random bred line (RR) and lines for large (LL) or small (SS) body weight. 2. T4 concentration increased in the order SS, RR, LL in both sexes and did not vary significantly between sexes; the SS line had a significantly higher value than that of the LL line. 3. The body temperatures of SS, RR and LL lines were 42.45, 42.03 and 41.25 degrees C in males, and 42.7, 42.03 and 41.63 degrees C in females. 4. The oxygen consumptions of SS, RR and LL lines were 63.4, 46.0 and 43.8 ml/kgW0.75 min. in males, and 61.4, 44.8 and 37.2 in females. The value for SS was significantly higher than those of RR and LL lines in both sexes (P < 0.01). The carbon dioxide productions of SS, RR and LL lines were 31.8, 33.8 and 27.3 ml/kgW0.75 min. in males, and 31.2, 31.9 and 27.3 in females. In both sexes, that of the LL line was significantly lower than those of the SS and RR lines (P < 0.01). 6. The heat productions of SS, RR and LL lines were 1.178, 0.994 and 0.842 kJ/kgW0.75 min. in males, and 1.142, 0.879 and 0.736 in females. In both sexes, the heat production of the SS line was higher than those of the RR and LL lines (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

PubMed1994

A high prevalence of human T-lymphotropic virus type I carriers in patients with antithyroid antibodies.

Human T-lymphotropic virus type I (HTLV-I) is a causative retrovirus of adult T-cell leukemia lymphoma and HTLV-I associated myelopathy/tropical spastic paraparesis. HTLV-I is also associated with some forms of pulmonary alveolitis, chronic arthropathy, polymyositis, and uveitis. In this study, the possible role of HTLV-I infection in the pathogenesis of autoimmune thyroid diseases with positive antithyroid antibody (ATA) to microsomal antigen or thyroglobulin was evaluated. In Fukuoka Prefecture or the northern part of Kyushu Island located in the southwestern part of Japan, the prevalence of patients with HTLV-I antibody was screened using the particle agglutination test and then was further confirmed either by the indirect immunofluorescence method or the western blot method. The observed prevalence in patients with thyroid disorders and the estimated prevalence calculated considering the sex- and age-specific prevalence among healthy blood donors (n = 16,008) were as follows: 19 (7.4%) vs 7.8 (3.0%) (p < 0.001) for ATA-positive chronic thyroiditis (n = 257), 21 (7.0%) vs 6.6 (2.2%) (p < 0.001) for ATA-positive Graves' disease (n = 298), 4 (4.3%) vs 2.1 (2.2%) (ns) for ATA-negative Graves' disease (n = 94), 1 (2.9%) vs 1.1 (3.1%) (ns) in ATA-negative hypothyroidism (n = 35), and 3 (1.8%) vs 5.0 (2.9%) (ns) for ATA-negative nodular goiter (n = 170). These findings thus suggest that HTLV-I infection may have some relationship to ATA-positive thyroid disorders.

Adult↗

PubMed1994

The role of net charge on the renaturation of reduced lysozyme by the sulfhydryl-disulfide interchange reaction.

Reduced and acetylated lysozymes are basic proteins. When their amino groups were variously acetylated and then renatured by sulfhydryl-disulfide (SH-SS) interchange reaction at pH 8.0, the final folding yield decreased as the number of positive charges decreased. The final folding yield of native and Ac1 lysozyme, with one positive charge eliminated, was less sensitive to increasing protein concentration than that of Ac2 lysozyme, where two positive charges had been eliminated. The final folding yield of reduced Ac2 lysozyme increased in the presence of 1 M urea, which reduced the aggregation of unfolded lysozyme. Thus, the aggregation of unfolded lysozymes, which leads to a decrease in the final folding yield, was found to be heavily dependent on their net charges. Moreover, the final folding yield of reduced lysozyme was shown to be increased by use of cystamine as an oxidizing reagent in comparison with 2-hydroxyethyl disulfide or dithiodiglycolic acid. This may support the idea that the final folding yield is influenced by electrostatic interaction between unfolded lysozymes in the early stage of renaturation. In contrast, the concentration dependency of the final folding yield of Ac1 lysozyme was different from those of carboxymethylated His15 and Asp106 lysozymes whose positive net charges were similar to that of Ac1 lysozyme. On the basis of the observations, it is suggested that the formation of the aggregates in the renaturation process might also be affected by the structure of the unfolded state of lysozyme in solution.

Acetylation↗

PubMed1994

Phosphatidylserine suppresses myelin-induced experimental allergic neuritis (EAN) in Lewis rats.

Phosphatidylserine administered as an aqueous dispersion to myelin-induced experimental allergic neuritis rats had a significant effect on disease course. Intraperitoneal injections of 30 mg/kg were given daily beginning at the onset of disease and continued for 14 days. Clinical severity and mortality were markedly reduced by this treatment as compared to saline controls. Improved clinical outcome was associated with a reduction in peripheral nerve pathology. A possible mechanism involving tumor necrosis factor is discussed.

Animals↗

PubMed1994

Possible involvement of protein kinase C activation in down-regulation of CD3 antigen on adult T cell leukaemia cells.

The role of protein kinase C (PKC) system on CD3 expression on adult T-cell leukaemia (ATL) was examined. The down-regulation of CD3 on ATL cells is reportedly induced by CD3 down-regulating factor (CD3DF) contained in serum and culture supernatants of leukaemia cells from acute type ATL patients. After we cultured normal PBMC with a PKC inhibitor, H-7, CD3DF activity for PBMC was reduced significantly. Culture with H-7 of HTLV-1 transformed T cells, ATL-2 cells whose CD3 expression had been decreased, led to enhancement of CD3 expression in a time-dependent manner. These findings suggest that CD3DF may play an important role as a PKC system activator, resulting in CD3 down-regulation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1994

Parvovirus B19-associated haemophagocytic syndrome with prominent neutrophilia.

We describe a patient with both haemophagocytic syndrome and acute myocarditis probably associated with parvovirus B19 infection. The patient had a marked neutrophilia instead of neutropenia more usually observed in virus-associated haemophagocytic syndrome (VAHS). Endogenous serum concentrations of macrophage colony-stimulating factor (M-CSF), granulocyte colony-stimulating factor (G-CSF), and tumour necrosis factor-alpha (TNF-alpha) were higher than normal, suggesting that these cytokines may be involved in the genesis of the observed syndrome.

Acute Disease↗

PubMed1994

Estimation of Der p and Der f I quantities in the reference preparations of Dermatophagoides mite extracts.

A monoclonal antibody-based enzyme-linked immunosorbent assay (MoAb-ELISA) was developed to measure the major Dermatophagoides mite allergens, Der p I and Der f I. The assay was highly species-specific and sensitive. Using this assay system, the absolute mass unit of Der p I and Der f I in the reference preparations of the extracts was estimated. The primary standards used were the purified Der p I and Der f I preparations. The reference preparations of the D. pteronyssinus and D. farinae extracts (92-Dp and 92-Df), which had been prepared from the same amount of mite bodies of both species, were found to contain the same levels of the Der I allergens, 10.1 micrograms/ml of Der p I and 10.0 micrograms/ml of Der f I, respectively. A histamine release assay with leucocytes from mite-allergic donors showed that the total allergenic potency of 92-Dp and 92-Df was comparable. This results indicates that the estimated Der I levels in these extracts seem to be valid, at least, in the balance between the two species, although further comparisons of the absolute quantities by several different laboratories are needed. The Der I levels in the WHO/IUIS international reference preparation of D. pteronyssinus and the CBER standard mite extracts, E4-Dp and E5-Df, were also estimated using this assay system. They were found to contain 4.4 micrograms/vial and 13.3 micrograms/ml of Der p I and 9.5 micrograms/ml of Der f I, respectively.

Allergens↗

PubMed1994

A variant form of hypobetalipoproteinaemia associated with ataxia, hearing loss and retinitis pigmentosa.

A six-year-old Japanese boy had ataxia, mental retardation, peripheral neuropathy, proximal myopathy, hearing loss, retinitis pigmentosa and deficiencies in apolipoprotein AI, B, CII and CIII. His clinical features except for hearing loss resembled those of abetalipoproteinaemia or symptomatic hypobetalipoproteinaemia, but his apolipoprotein abnormalities were distinct from these disorders. He had apolipoprotein B-100 with a normal molecular weight. Although most of his neurological manifestations were compatible with those of vitamin E deficiency, their early onset and the presence of hearing loss was unusual for that condition. There has been slight deterioration of ataxia during two years follow-up despite high-dose vitamin E supplementation. Other abnormalities in lipid metabolism might be associated with the neurological damage in this case.

Ataxia↗

PubMed1994

Evaluation and interpretation of symptom structures in patients with schizophrenia.

Seventy Japanese DSM-III-R schizophrenic patients were assessed for 30 clinical symptoms using the Positive and Negative Syndrome Scale (PANSS) of Kay et al. Principal component analysis was applied to the full item set of this scale and disclosed 5 orthogonal independent symptom groups: negative, hostile/excited, thought-disordered, delusional/hallucinatory and depressive components. Our results provided further support of the contention that more than 2 (i.e., positive and negative) dimensions are required to account for structures of the schizophrenic symptoms.

Adolescent↗

PubMed1994

Vasopressin-independent regulation of collecting duct water permeability.

Studies were conducted in microdissected rat terminal inner medullary collecting duct (IMCD) segments to determine whether agents that activate the phosphoinositide signaling pathway regulate osmotic water permeability independent of the action of vasopressin. Water was withheld from the rats for 24 h before the experiments, a procedure that yields a stably high osmotic water permeability in isolated perfused terminal IMCDs in the absence of vasopressin. In the present studies, the vasopressin-independent osmotic water permeability was sustained at approximately 300 microns/s for at least 90 min. We used the cholinergic agent carbachol (10-100 microM) to activate the phosphoinositide pathway. This agent has previously been reported to increase the hydrolysis of inositol phospholipids in IMCD cells without altering adenosine 3',5'-cyclic monophosphate production. In preliminary studies, we demonstrated (using fura 2) that carbachol transiently increases intracellular calcium and that this response was blocked by atropine, confirming that muscarinic receptors are coupled to activation of the phosphoinositide signaling pathway in these cells. In the absence of vasopressin, both carbachol (10 microM) and phorbol myristate acetate (1 nM) inhibited osmotic water permeability by 40-50% within 10 min. These effects were partially blocked by calphostin C, an inhibitor of protein kinase C. These results demonstrate that activation of phosphatidylinositol hydrolysis and/or activation of protein kinase C markedly inhibits osmotic water permeability in isolated perfused IMCD segments, even in the absence of prior stimulation by vasopressin.

Animals↗