[Cholesteryl ester transfer protein (CETP)].
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Biomedical subjects
Publications and source records attributed to T Teramoto.
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Coronary heart disease (CHD) mortality and plasma cholesterol level have increased in Japan. There has been evidence indicating that cholesterol-lowering is effective in secondary and primary prevention of CHD. Hypercholesterolemia has been defined as over 220 mg/dl, and over 140 mg/dl for LDL-cholesterol. These levels were determined on the base of the evidence observed in Japan. The subjects are divided as follows, A: no CHD and no other risk factors, B: no CHD and at least one risk factor, C: manifest CHD. The treatment levels of LDL-cholesterol are 140 mg/dl for category A, 120 mg/dl for B and 100 mg/dl for C. Although drug therapy may be necessary when LDL-cholesterol level is over 120 mg/dl in category C, life-style modification is most important in category A and B.
Recent genetic and molecular biological analyses have revealed many forms of inherited channelopathies. Homozygous ataxic mice, tottering (tg) and leaner (tgla) mice, have mutations in the P/Q-type Ca2+ channel alpha1A subunit gene. Although their clinical phenotypes, histological changes, and locations of gene mutations are known, it remains unclear what phenotypes the mutant Ca2+ channels manifest, or whether the altered channel properties are the primary consequence of the mutations. To address these questions, we have characterized the electrophysiological properties of Ca2+ channels in cerebellar Purkinje cells, where the P-type is the dominant Ca2+ channel, dissociated from the normal, tg, and tgla mice, and compared them with the properties of the wild-type and mutant alpha1A channels recombinantly expressed with the alpha2 and beta subunits in baby hamster kidney cells. The most striking feature of Ca2+ channel currents of mutant Purkinje cells was a marked reduction in current density, being reduced to approximately 60 and approximately 40% of control in tg and tgla mice, respectively, without changes of cell size. The Ca2+ channel currents in the tg Purkinje cells showed a relative increase in non-inactivating component in voltage-dependent inactivation. Besides the same change, those of the tgla mice showed a more distinct change in voltage dependence of activation and inactivation, being shifted in the depolarizing direction by approximately 10 mV, with a broader voltage dependence of inactivation. In the recombinant expression system, the tg channel with a missense mutation (P601L) and one form of the two possible tgla aberrant splicing products, tgla (short) channel, showed a significant reduction in current density, while the other form of the tgla channels, tgla (long), had a current density comparable to the normal control. On the other hand, the shift in voltage dependence of activation and inactivation was observed only for the tgla (long) channel. Comparison of properties of the native and recombinant mutant channels suggests that single tottering mutations are directly responsible for the neuropathic phenotypes of reduction in current density and deviations in gating behavior, which lead to neuronal death and cerebellar atrophy.
The relationship between transforming growth factor-beta1 (TGF-beta1) induced growth arrest and apoptosis in rat liver derived epithelial (RLE) cells was analyzed. TGF-beta1 treatment of RLE cells induced both cell cycle arrest and apoptosis. However, pretreatment of the cells with either dexamethasone or cyclohexamide suppressed TGF-beta1 induced apoptosis, without preventing the cell cycle arrest. Both p53 and Bax were subsequently shown to be overexpressed during the TGF-beta1 induced apoptosis. Furthermore, it was revealed that cycloheximide suppressed expression of both p53 and Bax. In contrast, dexamethasone treatment prevented Bax expression alone. Treatment of RLE cells with several growth factors either alone or in combination was ineffective in counteracting TGF-beta1 induced apoptosis. In additon, we show that TGF-alpha also induced both p53 and Bax expressions and augmented TGF-beta-induced apoptosis. Thus, p53 and Bax are likely to be key factors in TGF-beta1 induced apoptosis in RLE cells.
A functionally silent nucleotide substitution of the sterol 27-hydroxylase gene (CYP 27), identified in two families with cerebrotendinous xanthomatosis (CTX), was confirmed to cause alternative pre-mRNA splicing of the gene. Full-length RT-PCR analysis of the CYP 27 gene in a patient from one of the CTX families revealed one major and an additional faint band. Sequence analysis of the cloned RT-PCR product showed three species of cDNA: 3' terminal 13 bp of exon 2 deleted cDNA, exon 2 skipped cDNA, and full-length cDNA with a functionally silent G to T mutation at codon 112 (GGG 112Gly to GGT 112Gly). Only a single base change was identified by genomic DNA sequence analysis of the CYP 27 gene in the patient: T replaced G at the third position of codon 112, 13 bp upstream from the 3' terminus of exon 2. Transfection of constructed minigenes, with or without the mutation, confirmed that this silent mutation resulted in alternative pre-mRNA splicing by activating a cryptic 5' splice site around the mutant codon. The mutation was also identified in two patients from another CTX family, with a compound heterozygous pattern of A for G substitution at codon 372, a mutation reported previously by our group. The results elucidate a novel molecular basis for the CTX and suggest the significance of a silent nucleotide substitution with regard to pre-RNA splicing.
Patients with IgG2 deficiency have recurrent sinopulmonary infections caused by Pneumococcus and Hemophilus. Hereditary and selective IgG2 deficiency was suspected in two Japanese siblings whose serum IgG2 levels were under detection limits, while other serum levels of immunoglobulin subclasses were within normal ranges. Expression level of spontaneous germline Cgamma2 transcript was normal, but that of the spontaneous mature Cgamma2 transcript was greatly decreased in the patients' PBMCs, suggesting the presence of a defect at or after the class switch to Cgamma2. We sequenced the Cgamma2 gene region, and in both patients a homozygous one-base insertion (1793insG) was present in exon 4 of the Cgamma2 gene, just upstream from the alternative splice site for M exons. The mutant membrane-bound gamma2 heavy chain loses the transmembrane domain and the evolutionarily conserved cytoplasmic domain. Considering several lines of evidence showing that intact expression of the membrane-bound heavy chain is essential for a normal response of B cells and production of secreted immunoglobulin in mice, we concluded that 1793insG is responsible for selective and complete IgG2 deficiency in these two siblings. This is the first documentation of a mutation in human selective IgG2 deficiency.
BACKGROUND AND OBJECTIVES: 1-Ethyl-2-¿[3-ethyl-5-(3-methylbenzothiazolin-2-yliden)]-4-+ ++oxothiazolidin-2-ylidenemethyl¿pyridium chloride (MKT-077, formerly known as FJ776), a delocalized lipophilic cation, is known to accumulate in the mitochondria, according to the negative potential inside the mitochondria, and exert its cytotoxicity. METHODS: The single-cell suspensions of human cancer cell lines, human spleen cells, and fresh cancer specimens obtained from patients with gastric carcinoma were used for the 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay. RESULTS: The antitumor activity of MKT-077 was dose and concentration related, and 50% inhibitory concentrations (IC50) ranged from 1.7 to 14.3 microg/ml, with a mean +/- standard deviation (SD) of 8.4 +/- 4.6 microg/ml. The IC50 of fresh surgical spleen-cell specimens ranged from 0.34 microg/ml to >100 microg/ml in a 48 h incubation, with a mean +/- SD of 66.5 +/- 37.7 microg/ml. When the antitumor activity of MKT-077 was compared between gastric cancer cells and spleen cells obtained from the same patient, the concentration-dependent antitumor activity of this agent was obvious in the cancer cells, while no significant cytotoxicity was observed in the spleen cells. The fresh surgical specimens of gastric cancer showed higher sensitivity to MKT-077 than did spleen cells at a concentration of 30 microg/ml, with a statistically significant difference at P < 0.05. CONCLUSIONS: The selective antitumor activity of MKT-077 was confirmed using fresh surgical specimens and warrants further investigation.
We analyzed the data regarding six Japanese ataxia-telangiectasia (A-T) patients from four unrelated families, at the DNA level, to search for possible common mutations in the Japanese population. Among eight mutant alleles in the four families, c. 4612del165 (exon 33 skipping) was identified in two alleles, and c. 5749A to T (R1917X), c. 7471T to C (W2491R), c.7883de15, and c. 8725A to G (R2909G) were identified in one allele each. We found no mutations in the other two alleles. The IVS33 + 2T-->A mutation was identified at the genomic level as the cause of exon 33 skipping. We also identified the IVS33 + 2T-->A mutation in a Japanese patient ATL105 who was previously found to be a homozygote of c. 4612del165. W2491R and R2909G mutations were not detected in more than 100 control Japanese alleles. The latter is located in a highly conserved PI-3 kinase domain and is a completely conserved residue among ATM-related proteins. Taken together with previously documented mutations in five other Japanese A-T patients, IVS33 + 2T-->A and 7883del5 were identified in four and five alleles, respectively, in a total of 18 mutant alleles of Japanese A-T patients. These results suggest that these two mutations are relatively common mutations in the Japanese population.
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The reestablishment of anal function by transposition of the gracilis muscle, combined with the implantation of electrodes and a neuromuscular stimulator (dynamic graciloplasty), has recently been developed. With this method, the transposed muscle maintains contraction by electrical stimulation to maintain neoanal pressure without fatigue. It is necessary to convert the fatigue-prone gracilis muscle to fatigue-resistant muscle by long-term electrical stimulation (conditioning). In most patients receiving dynamic graciloplasty, the conditioning is accomplished after the transposition. However, conditioning before graciloplasty should reduce the risk of ischemia in the transposed muscle after the graciloplasty and improve the outcome. This new sequence of procedures is described, in combination with J-pouch construction, in a patient who required abdominoperineal excision of the rectum for lower rectal cancer. The graciloplasty was performed after conditioning of the gracilis muscle in situ; the conditioning did not cause the patient discomfort and resulted in good anal function.
omega-Conotoxin GVIA and omega-agatoxin IVA are specific peptide blockers of N- and P/Q-type calcium channel, respectively. Effects of their intracerebroventricular injection (1-3 pmol/mouse) on psychostimulant-induced hyperactivity were investigated in mice. omega-Conotoxin GVIA antagonized methylphenidate-, methamphetamine- and phencyclidine-induced hyperactivity in a dose-dependent manner. omega-Agatoxin IVA blocked methylphenidate-induced but not methamphetamine- or phencyclidine-induced hyperactivity. Neither peptides showed any effect on apomorphine-induced hyperactivity or spontaneous activity, suggesting that the inhibitory effects on psychostimulant-induced hyperactivity are not due to dopamine receptor blockage or nonspecific behavioral depression. Antagonism of calcium channels, particularly N-type, may ameliorate activation of the dopaminergic system induced by increased dopamine release.
BACKGROUND: In patients with atopic diseases such as bronchial asthma and atopic dermatitis, an elevated serum IgE level is common. Several studies showed that interleukin-4(IL-4) and interferon-gamma (IFNgamma) are important for regulation of IgE production. OBJECTIVES: The study was designed to examine the pathogenesis of an elevated serum IgE level at the production levels of TH1-type and TH2-type cytokines. METHODS: The production of interleukin-2 (IL-2), IL-4, interleukin-5 (IL-5) and IFNgamma by peripheral blood mononuclear cells (PBMCs) stimulated with phytohemagglutinin (PHA) was analysed in 20 individuals with various serum IgE levels. The amount of IFNgamma mRNA in the stimulated PBMCs was analysed using a quantitative polymerase chain reaction method. RESULTS: Cytokine production was analysed simply as a function of serum IgE level. The serum IgE level was negatively correlated with the amount of IFNgamma secreted by PBMCs (n = 20, R = -0.724, P<0.005) when logarithmically transformed data were analysed, but were not or were only weakly correlated with those of IL-4, IL-2, or IL-5 secreted by these cells (n = 20). For investigation of the cause of reduced IFNgamma production in individuals whose serum IgE level are high, the amount of IFNgamma mRNA was determined. The levels of IFNgamma mRNA expression in the stimulated PBMCs correlated well with the amount of IFNgamma secreted by the PBMCs (n = 8, R = 0.947, P < 0.001). CONCLUSIONS: Reduced IFNgamma production ability due to reduced IFNgamma mRNA expression in PBMCs is associated with an elevated serum IgE level in atopic patients.
BACKGROUND: It is not sufficient to predict 'high allergic risk newborns' on the basis of increased IgE concentrations of cord blood alone, because a raised cord blood IgE concentration is specific but not sensitive in the prediction of the development of allergic disorders. Warner et al. have reported that interferon gamma (IFN-gamma) production by allergen-triggered cord blood cells is a predictor of atopic eczema, based on the 1-year follow-up study. OBJECTIVE: We examined whether IFN-gamma production by antigen-stimulated cord blood mononuclear cells (CBMCs) is a risk factor of allergic disorders, based on the 6-year follow-up study. METHODS: The relationships among cord blood IgE concentrations, IFN-gamma and interleukin-2 (IL-2) productions by antigen-stimulated CBMCs, and the development of allergic disorders in 21 infants for 6 years were investigated. RESULTS: Atopic dermatitis, atopic dermatitis and allergic rhinitis, or atopic dermatitis and bronchial asthma developed in seven of 21 subjects. The maximal IFN-gamma concentration in culture supernatants of ovalbumin (OA) or bovine serum albumin (BSA) stimulated CBMCs in infants who developed allergic disorders was significantly lower (P < 0.01) than that in infants who did not develop any allergic disorders. In contrast, the maximal IL-2 concentration in culture supernatants of OA- or BSA-stimulated CBMCs in infants who developed allergic disorders was not lower than in infants who did not develop any allergic disorders. Moreover, the IFN-gamma concentrations were negatively correlated with cord blood IgE concentrations. CONCLUSION: Reduced IFN-gamma production by antigen-stimulated CBMCs is a risk factor of allergic disorders.
In mice, Pax5 gene is indispensable for B cell development. Pax5-deficient mice fail to produce mature B cells owing to complete arrest of B cell development at a precursor stage. However, the lineage and stage of human Pax5 gene expression have remained elusive. In this investigation expression of the human Pax5 gene was studied. Pax5 gene expression was detected in B cell lines but not in myeloma cell lines. CD19 expression was correlated with Pax5 gene expression. Adult spleen and bone marrow and fetal spleen and liver showed strong Pax5 gene expression, as did the corresponding mouse tissues, as reported previously. In common variable immunodeficiency (CVID) peripheral blood lymphocytes (PBL) with a decreased number of B cells, no Pax5 gene expression was detected. Some CVID PBL stimulated with IL-2, IL-10 and anti-CD40 monoclonal antibody, expressed the Pax5 gene. Defect of Pax5 gene expression in CVID may be caused by regulatory T cell disorder.
The tightly controlled homeostatic mechanisms between cell growth and apoptosis that exist in normal liver tissue are disrupted during hepatocarcinogenesis. The TGF (transforming growth factor)-beta signaling system is a central component of the mechanisms by which cell growth and apoptosis are controlled in the liver. The recent delineation of the TGF-beta signaling pathway has provided a unique framework for analysis of the impact that disruption of individual components of this signaling pathway can have on apoptosis during hepatocarcinogenesis. Here we review recent data on involvement of the TGF-beta signaling pathway in the dysregulation of apoptosis frequently observed in hepatocellular carcinomas. The data indicate that disruption of the TGF-beta pathway at the pre-receptor, receptor, and post-receptor levels occurs in hepatocellular carcinomas and can cause dysregulation of apoptosis. Also, substantial evidence now exists that phosphatidylinositol-3-kinase (PI3K) may function as an important negative regulator of the TGF-beta 1-induced apoptosis in hepatocellular carcinomas. Taken together, the available evidence indicates that disruption of the TGF-beta 1-induced apoptosis as well as growth inhibition is an important and integral part of the multistage process of liver carcinogenesis.
Human pepsinogen (PG) A and C were cloned in Escherichia coli, but the levels of expression were low and unstable. When there were fused to maltose-binding protein (MBP), the fusion proteins (MBP-PGA and MBP-PGC) were expressed as the major products. Although these fused products were almost totally recovered from the insoluble fraction, the renaturation and purification procedures were easy and simple. MBP-PGA and the PGA segment obtained by factor Xa digestion (designated as r-PGA) possessed proteolytic activities equivalent to native PGA purified from gastric tissue (t-PGA). For PGCs (MBP-PGC, r-PGC and t-PGC) also, the specific activities were almost the same. However, the activities of PGCs were about 3- to 4-hold higher than those of PGAs. In PGA and PGC immunoassay systems, r-PGs (r-PGA and r-PGC) and the EIA kit standard PGs (gastric mucosal PGs) exhibited a good correlation. From these results, r-PGs would seem to be applicable as assay standards without compromising the sensitivity of the immunoassay systems.
We have previously shown that fatty liver is easily induced in suncus by starvation and that the plasma level of apolipoprotein B (apo B) is very low. We also found that hepatic acyl coenzyme A cholesterol acyltransferase (ACAT) activity is almost absent in the animals, resulting in decreased cholesteryl ester contents in the liver. A deficiency of cholesteryl ester in suncus liver may be one of the reasons for the defect in the assembly process of apo B-containing lipoproteins, leading to a low level of plasma apo B. Another possible explanation for the induction of fatty liver in suncus is a defect in apo B-processing in the liver. In this study, we investigated the hepatic synthetic rate and intrahepatic degradation of apo B using primary cultured hepatocytes derived from suncus and rats. In order to estimate intrahepatic degradation of apo B, we added N-acetylleucyl-leucynorleucinal to the culture medium as an inhibitor of apo B degradation. The basal synthesis of apo B in suncus hepatocytes was 50% of that in rat. Intracellular degradation of apo B was not observed in suncus hepatocytes, while it was obvious in rat hepatocytes. This evidence suggests that the lower secretion rate of apo B lipoprotein is not due to the intrahepatic degradation of apo B, but may be due to the low synthetic rate of apo B.
cDNA for an acidic class III chitinase (ChitW1) was isolated from winged bean cells. The chitinase was abundantly secreted at later stages of cell culture, when levels of ChitW1 mRNA were also high. The gene was strongly expressed in roots, but a class I chitinase was strongly expressed in leaves.