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Biomedical subjects

H Yoshida

Publications and source records attributed to H Yoshida.

At least 379 records · Page 21Linked to original sources
PubMed2000

Intralobar bronchopulmonary sequestration evaluated by contrast-enhanced three-dimensional MR angiography.

Bronchopulmonary sequestration (PS) is characterized by non-functioning lung tissue fed from one or several aberrant systemic arteries. The condition is diagnosed by visualizing the feeding arteries using non-invasive CT, MRI, colour Doppler sonography or conventional angiography. We present a 5-year-old boy in whom intralobar sequestration was diagnosed using contrast-enhanced 3D MR angiography, which visualised fine blood vessels in the thoraco-abdominal region without arterial puncture. This technique is useful for diagnosing PS.

Bronchopulmonary Sequestration↗
PubMed2000

Cardiac sympathetic dysfunction contributes to left ventricular remodeling after acute myocardial infarction.

To investigate the role of the cardiac sympathetic nervous system in left ventricular remodelling, 50 patients with first-time acute myocardial infarction (AMI) and patency of the infarct-related artery after reperfusion underwent quantitative iodine-123 metaiodobenzylguanidine (MIBG) imaging at 4 days and 4 weeks (n=42), and quantitative technetium-99m tetrofosmin imaging at 2 days after AMI. They also underwent both ventriculography and coronary angiography on admission and about 4 weeks after AMI. On the basis of left ventricular end-systolic volume (LVESV), patients were divided into two groups. Patients with LVESV dilatation (n=20) had a significantly lower ejection fraction (P<0.003) and a significantly higher severity score of 99mTc-tetrofosmin (P<0.04), and total severity (P<0.01), delta extent (P<0.007) and delta severity (P<0.0008) scores of MIBG than patients without LVESV dilatation (n=30). delta severity score of MIBG was directly correlated with change in LVESV at 4 weeks (r=0.63, P<0.0001). Stepwise linear discriminant function analysis showed that delta severity score of MIBG (P<0.0002) was the only discriminator of LVESV dilatation. Patients with LVESV dilatation had higher regional washout rates in both the infarct and the non-infarct zones than patients without such dilatation. Furthermore, no MIBG parameters changed significantly between 4 days and 4 weeks after AMI. In reperfused AMI, delta severity score of MIBG was related to the degree of ventricular dilatation and was the only powerful discriminator of ventricular dilatation. These results suggest that cardiac sympathetic nervous abnormality might contribute to left ventricular remodelling in reperfused AMI. MIBG imaging may allow identification of reperfused AMI patients at high risk for left ventricular remodelling.

3-Iodobenzylguanidine↗
PubMed2000

Experimental immune-mediated blepharoconjunctivitis in rats induced by immunization with ragweed pollen.

BACKGROUND: A study was performed to compare the effects of immunization with ragweed pollen (RW) in two different adjuvants on the characteristics of a previously described model of experimental immune-mediated blepharoconjunctivitis (EC) in rats. METHODS: Lewis or Brown Norway (BN) rats were immunized with 100 microg of RW in emulsion with aluminum hydroxide [Al(OH)3] or complete Freund's adjuvant (CFA). Three weeks later, the animals were challenged with eye drops containing RW in PBS. Twenty-four hours after topical challenge, eyes, blood, and lymph nodes were obtained for histology, measurement of antigen-specific antibodies, and proliferation or cytokine assays, respectively. In addition to active immunization, recipients of RW-primed lymph node cells were challenged and evaluated as above. RESULTS: RW in both adjuvants induced infiltration with predominantly mononuclear cells in Lewis rats and eosinophils in BN rats. As well as active immunization, eosinophils were detected only in BN rats by adoptive transfer of cells. Lymphocyte proliferative responses to RW were high in immunized Lewis rats when CFA was used as an adjuvant. In contrast, proliferative responses in BN rats were higher when Al(OH)3 was used. RW-specific IgE was detected only in BN rats. There were no significant differences in RW-specific IgG1/IgG2a ratio among the four groups. Lewis rats had higher level of RW-specific interferon-gamma in the culture supernatant. CONCLUSIONS: The characteristics of EC are different in Lewis and BN rats, dependent on the genetic background of the rat strains. The response to RW was similar to other previously used antigens, such as ovalbumin.

Allergens↗
PubMed2000

Alteration of the membrane lipid environment by L-palmitoylcarnitine modulates K(ATP) channels in guinea-pig ventricular myocytes.

Sarcolemmal adenosine 5'-triphosphate-sensitive K+ channels (K(ATP)) are dramatically up-regulated by a membrane phospholipid, phosphatidyl-inositol-4,5-bisphosphate (PIP2). During ischaemia, L-palmitoylcarnitine (L-PC), a fatty acid metabolite, accumulates in the sarcolemma and deranges the membrane lipid environment. We therefore investigated whether alteration of the membrane lipid environment by L-PC modulates the K(ATP) channel activity in inside-out patches from guinea-pig ventricular myocytes. L-PC (1 microM) inhibited KATP channel activity, without affecting the single channel conductance, through interaction with Kir6.2. L-PC simultaneously enhanced the ATP sensitivity of the channel [concentration for half-maximal inhibition (IC50) fell from 62.0+/-2.7 to 30.3+/-5.5 microM]. In contrast, PIP2 attenuated the ATP sensitivity (IC50 343.6+/-54.4 microM) and restored Ca2+-induced inactivation of KATP channels (94.1+/-13.7% of the control current immediately before the Ca2+-induced inactivation). Pretreatment of the patch membrane with 1 microM L-PC, however, reduced the magnitude of the PIP2-induced recovery to 22.7+/-6.3% of the control (P<0.01 vs. 94.1+/-13.7% in the absence of L-PC). Conversely, after the PIP2-induced recovery, L-PC's inhibitory action was attenuated, but L-PC partly reversed the PIP2-mediated decrease in the ATP sensitivity (IC50 fell from 310+/-19.2 to 93.1+/-9.8 microM). Thus, interaction between L-PC and PIP2 in the plasma membrane appears to regulate K(ATP) channels.

Adenosine Triphosphate↗
PubMed2000

Abdominal multivisceral transplantation in pigs.

We investigated the technical aspects of porcine abdominal multivisceral transplantation, in terms of pathophysiological features in animals given no immunosuppresant. The splanchnic organs of the donor animal were flushed in situ with University of Wisconsin solution via the abdominal aorta, using a pump. After a relatively short period of cold storage in saline, multivisceral grafts, including the liver, pancreas, and gastrointestinal tract, were transplanted orthotopically. Of the 18 recipient pigs that underwent the operation, 9 (50%) died within 24 h, mainly because of respiratory insufficiency (n = 5) and circulatory shock (n = 3). Three animals (17%) were lost to acute renal failure between the second and fifth postoperative days. Six pigs (33%) survived for more than 1 week, and the causes of death in these animals were bowel obstruction (n = 1), pneumonia (n = 2), rejection of the intestinal graft (n = 2), and deterioration (n = 1). Although the results of this study were not satisfactory, abdominal multivisceral transplantation using pigs is practical and may lead to the possible resolution of various problems, in regard to the immunologic aspects and the interrelationship of transplanted complex organs.

Animals↗
PubMed2000

High prevalence of anticardiolipin antibodies in hepatitis C virus infection: lack of effects on thrombocytopenia and thrombotic complications.

Hepatitis C virus (HCV) causes various extrahepatic immunologic abnormalities. Recently, an association between HCV infection and antiphospholipid syndrome, including thrombocytopenia, has been reported. However, the precise relationship between thrombocytopenia and anticardiolipin antibodies in patients with chronic HCV infection is not fully understood; likewise, the association of antiphospholipid syndrome and various liver diseases is not well understood. To evaluate the prevalence and importance of antiphospholipid antibodies in various chronic liver diseases, we determined the levels of anticardiolipin antibodies, platelet numbers, and levels of platelet-associated immunoglobulin G (PA-IgG) and thrombin-antithrombin III complex (TAT) in patients with chronic HCV infection, chronic hepatitis B virus (HBV) infection, and primary biliary cirrhosis (PBC). The prevalence of anticardiolipin antibodies in patients with HCV infection was significantly higher than that in control subjects or individuals with the other liver diseases examined. However, there was no significant correlation between anticardiolipin antibodies and platelet counts or TAT. The frequency of thrombotic complications was similar in anticardiolipin antibody-positive and -negative patients with chronic HCV infection. Further, sera from all but one anticardiolipin antibody-positive HCV patient were negative for phospholipid-dependent anti-beta2 glycoprotein I antibodies. Our results suggest that anticardiolipin antibodies are frequently found in patients with chronic HCV infection, but they do not appear to be of clinical importance. Immunologic disturbances induced by HCV or prolonged tissue damage in systemic organs as a result of the extrahepatic manifestations of HCV infection may induce the production of antibodies to various cardiolipin-binding proteins or phospholipids.

Antibodies, Anticardiolipin↗
PubMed2000

Ineffective control of murine cytomegalovirus by IE1-specific cytotoxic T lymphocytes during protracted infection in the lung.

Interstitial pneumonia caused by cytomegalovirus (CMV) is a fatal disease in immunocompromised patients. In order to examine the defense mechanism against the virus in the lung, we employed an intratracheal infection model in susceptible mice. In mice infected intratracheally with murine CMV, a protracted infection was observed where infectious virus was detected up to 21 days of infection. During this prolonged infection, massive accumulation in the lung of CD8+ T cells with activated phenotypes occurred and these CD8+ T cells showed direct ex vivo cytolytic activity against target cells pulsed with the nonamer peptide derived from IE1 protein of the virus, which has been shown to be the dominant epitope recognized by most of virus-specific CTL. Moreover, adoptive transfer of in vitro induced IE1 peptide-specific CTL line showed no anti-virus effect in the lung, although they were effective in the spleen. Hence, there is reason to assume the IE1-specific CTL induced in vivo or in vitro plays limited roles during the prolonged infection in the lung.

Animals↗
PubMed2000

Association of bone mineral density with polymorphism of the human matrix Gla protein locus in elderly women.

The contribution of genetic factors has been implicated in the determination of bone mass in twin and family studies. Some of the genes involved would regulate bone metabolism, bone formation, and resorption, all processes that determine bone mass. One candidate gene matrix Gla protein gene (MGP), has been implicated in the pathogenesis of bone loss through a repression of bone formation. To analyze the genetic background for osteoporosis in elderly women, we have investigated a possible association between the CA repeat polymorphism at the human MGP gene locus and bone mineral density (BMD) of radial bone in 460 elderly Japanese women. Genotypes were classified into six groups according to the number of CA repeats present, from 13 to 18 (alleles A1 through A6). BMD was expressed as the adjusted BMD (ADJBMD), which was the body mass index (BMI)- and age-adjusted average BMD. The 214 women who lacked an A2 allele (212 bp, containing 17 repeats of CA) had significantly lower adjusted BMD than the participants (n = 246) who possessed an allele of that size (mean +/- SD; 0.303 +/- 0.062 vs 0.315 +/- 0.062 g/cm2; P = 0.0382). This result suggests that genetic variation at the MGP locus is associated with some determinants for BMD in elderly women. Therefore, this locus should serve as one of the genetic markers for osteoporosis.

Aged↗
PubMed2000

Reconstruction of the vena cava with the peritoneum.

BACKGROUND: Reconstruction of the vena cava with an autologous vein requires extra incisions. Prosthetic material is associated with an increased risk of infection. We therefore created an animal model of vena cava reconstruction using the peritoneum. METHODS: A 2.5 x 2.5 cm piece of peritoneum was resected from 7 pigs weighing 30 to 40 kg. An oval window (long axis: 1.5 cm) was made in the infrarenal vena cava. This was repaired with the peritoneal patch fixed in alcohol. RESULTS: In 2 animals sacrificed at 5 hours, there was no evidence of thrombosis, but there was fibrin clot on the patches. Two animals sacrificed on day 8 exhibited excellent patency of the vena cava. Complete endothelialization of the patch was noted at day 15. At 6 weeks, the vena cava was healed. No infections or other problems were noted. CONCLUSIONS: The peritoneum is an accessible and safe substitute for reconstruction of the vena cava.

Animals↗
PubMed2000

Overexpression of low density lipoprotein receptor eliminates apolipoprotein B100-containing lipoproteins from circulation and markedly prevents early atherogenesis in apolipoprotein E-deficient mice.

Apolipoprotein E (ApoE) plays a pivotal role in the metabolism of apolipoprotein B (apoB)-containing lipoproteins. The defective apoE gene in humans can cause elevated plasma levels of apoB-containing lipoproteins such as chylomicron remnant and intermediate density lipoprotein (IDL). In this study, we examined whether liver-selective high-level expression of low-density lipoprotein receptor (LDLR) could affect the lipoprotein profile and atherogenesis in apoE-deficient (apoE-/-) mice. ApoE knockout mice expressing LDLR transgene in liver [apoE-/-;Tg(LDLR+/-)] were prepared after mating apoE-/- mice with the human LDLR transgenic mice. The apoE-/-;Tg(LDLR+/-) and littermate apoE-/- mice were fed a normal diet and sacrificed at 18 weeks of age. (1) The plasma levels of cholesterol and triglyceride in apoE-/-;Tg(LDLR+/-) mice were 51 and 33% lower than those of apoE-/- mice, respectively. (2) In the plasma of apoE-/-;Tg(LDLR+/-) mice, the levels of apoB-containing lipoprotein were reduced and apoB100-containg particles were totally eliminated. (3) By histochemical analysis, apoE-/-;Tg(LDLR+/-) mice showed drastic suppression of early atherogenesis; the lesion area of these mice was 1/70 of that in the littermate apoE-/- mice. These results indicate that, even in apoE-defective subjects, induction of hepatic LDLR expression could protect from early atherogenesis.

Animals↗
PubMed2000

Correlations between plasma platelet-activating factor acetylhydrolase (PAF-AH) activity and PAF-AH genotype, age, and atherosclerosis in a Japanese population.

Platelet-activating factor acetylhydrolase (PAF-AH), a plasma enzyme that hydrolyzes PAF and oxidized phospholipids, is thought to be involved in protecting cells against oxidative stress. A G(994) (M allele)-->T (m allele) mutation in the plasma PAF-AH gene, which results in a Val(279)-->Phe substitution in the mature protein, leads to a loss of catalytic activity. To elucidate the relationships among PAF-AH enzyme activity, genotype, age, and atherosclerosis, we assayed these parameters in a large Japanese population (n=3932) that consisted of three groups; a control group (healthy individuals; n=1684), a risk-factor group (individuals having at least one conventional risk factor for atherosclerosis; n=1398), and a diseased group (patients who had suffered a myocardial infarction or stroke; n=850). We observed a significantly increased frequency of the m allele in the diseased group as compared with the control or risk-factor groups. Plasma PAF-AH activity increased significantly with age in women in the control group with the MM and Mm genotypes, and in men in the control group with the MM genotype, but not in men with the Mm genotype. In both the risk-factor and diseased groups, however, no correlation was observed between plasma PAF-AH activity and age in subjects with either genotype. These results suggest that in individuals with the MM genotype, plasma PAF-AH activity may be increased in response to stresses induced by PAF and/or oxidized phospholipids that might accumulate with age, but that this response is not evident or reduced in healthy individuals with the m allele, or in subjects with atherosclerotic disease, or having risk factors. Together with our previous findings, the G(994)-->T mutation in the PAF-AH gene may be one of the genetic determinants for atherosclerotic disease in the Japanese population.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2000

Cyclic malyl anthocyanins in Dianthus caryophyllus.

3,5-Di-O-(beta-glucopyranosyl) pelargonidin 6''-O-4,6'''-O-1-cyclic malate and a previously reported cyanidin equivalent, 3,5-di-O-(beta-glucopyranosyl) cyanidin 6''-O-4,6'''-O-1-cyclic malate were identified from petals of deep pink and red-purple flower cultivars of Dianthus caryophyllus, respectively.

Anthocyanins↗
PubMed2000

Induction of Th1-type cytokines by lipoteichoic acid-related preparation isolated from OK-432, a penicillin-killed streptococcal agent.

We have isolated the lipoteichoic acid (LTA)-related molecule (OK-PSA) from OK-432, a streptococcal preparation, by an affinity chromatography on CNBr-activated Sepharose 4B-bound TS-2 monoclonal antibody (mAb) that neutralizes interferon (IFN)-gamma-inducing activity of OK-432. In in vitro experiments using human peripheral blood mononuclear cells (PBMC), OK-PSA induced IFN-gamma, interleukin (IL)-2, IL-12, IL-18, tumor necrosis factor (TNF)-alpha and TNF-beta that are generally called "Th1-type cytokines" both in protein and in mRNA levels. Furthermore, the neutralizing test using cytokine-specific antibodies demonstrated that IL-18 plays a most significant role for IFN-gamma- and killer cell-inducing ability of OK-PSA among the other cytokines tested. These findings clearly indicated that OK-PSA, an LTA-related molecule, is a main effective component of OK-432, and is a potent inducer of Th1-type cytokines by T cell and natural killer (NK) cell activation mediated by monocytes-derived IL-18, and that it may be a useful immunotherapeutic agent for the patients with malignancies better than original OK-432.

Animals↗
PubMed2000

Purification and characterization of cytokine-inducing protein of seed extract from Aeginetia indica L., a parasitic plant.

We have isolated 55 kDa protein from the seed extract of Aeginetia indica L. (AIL), a parasitic plant, by an affinity chromatography on N-hydroxysuccinimide (NHS)-activated Sepharose High Performance column bound F3 monoclonal antibody which neutralizes cytokine-inducing and antitumor effect of AIL. In in vitro model using human peripheral blood mononuclear cells (PBMC), the 55 kDa protein (AILb-A) induced multiple cytokines, such as IFN-gamma, tumor necrosis factor (TNF)-alpha, granulocyte macrophage-colony stimulating factor (GM-CSF), IL-2, IL-6, IL-10, IL-12 and IL-18, and also accelerated killer cell activities of PBMC. When compared with a commonly used immunotherapeutic agent OK-432, AILb-A induced Th1 cytokines are greater than OK-432. Of the Th2 cytokines, the amounts of IL-6 and IL-10 induced by AILb-A were lower than those by OK-432. No significant induction of IL-4 and IL-13 was observed in AILb-A-stimulated PBMC. TNF family including TNF-alpha, TNF-beta, Fas ligand (FasL) and TNF-related apoptosis-inducing ligand (TRAIL) were suggested to be important for AILb-A-induced killing activity of PBMC by reverse transcription-polymerase chain reaction (RT-PCR) analysis. Furthermore, the neutralizing test using cytokine-specific antibodies demonstrated that IL-18 plays a most significant role for IFN-gamma- and killer cell-inducing ability of AILb-A among the cytokines tested. These findings clearly indicated that AILb-A, a 55 kDa protein of AIL, is a potent Th1 cytokine inducer and may be a useful immunotherapeutic agent for the patients with malignancies.

Adjuvants, Immunologic↗
PubMed2000

Insertion/deletion polymorphism in ACE gene is not associated with renal progression in Japanese patients with IgA nephropathy.

We determined the relationship between the gene polymorphism of angiotensin I-converting enzyme (ACE) and the progression of immunoglobulin A (IgA) nephropathy in a large cohort in a multicenter trial of ethnically homogeneous Japanese patients (n = 527). Patients with biopsy-proven IgA nephropathy were recruited from several clinics in Japan. The mean observation period was 8.4 +/- 4.7 years. ACE insertion/deletion (I/D) genotype was determined by polymerase chain reaction amplification using allele-specific primers. Clinical factors investigated in all patients were date of birth, sex, levels of urinary protein excretion, duration of observation, serum creatinine (sCr) level, and creatinine clearance (CCr). ACE genotype distribution did not differ between patients who maintained normal renal function (II, 41%; ID, 44.7%; DD, 14.3%) and those who progressed to renal impairment (II, 41.7%; ID, 40.4%; DD, 17.9%). Kaplan-Meier analysis did not show a significant difference in renal survival rate among the three groups of each genotype. In multivariate analysis, only two variables, proteinuria greater than 1.0 g/d of protein and impaired renal function (sCr >1.2 mg/dL or CCr <70 mL/min) at the time of renal biopsy, were found to be risk factors for disease progression leading to a poor outcome. No association was observed between these variables and ACE genotype. It appears that ACE I/D polymorphism may not affect the progressive deterioration of renal function in patients with IgA nephropathy from our multicenter trial.

Adult↗