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Biomedical subjects

F Takaku

Publications and source records attributed to F Takaku.

At least 217 records · Page 12Linked to original sources
PubMed1990

Plasma cholesterol-lowering activity of monocyte colony-stimulating factor (M-CSF).

We investigated the action of monocyte colony-stimulating factor (M-CSF) on plasma cholesterol metabolism. Recombinant human monocyte colony-stimulating factor (rhM-CSF) was intravenously injected into Watanabe heritable hyperlipidemic (WHHL) rabbits that were deficient in LDL receptor. The treated rabbits showed decreases in plasma total cholesterol levels from 493 +/- 39 to 416 +/- 45 mg/dl (about 15%) during the treatment. The decrease in total plasma cholesterol level was due to decreased levels of lipoproteins containing apo B 100 such as VLDL, IDL, and LDL. The effect of M-CSF on the LDL-receptor-deficient animal in vivo and evidence from Northern blot analysis of liver suggested that M-CSF lowers plasma cholesterol level through activated uptake of lipoproteins containing apo B 100 via pathways other than the hepatic LDL receptor. We have started a clinical study to evaluate the plasma cholesterol-lowering effect of M-CSF in patients with familial hypercholesterolemia, and have observed a decreased in total plasma cholesterol level in one of three patients treated with M-CSF. M-CSF may provide new insight into plasma cholesterol metabolism and a possible new tool to treat patients with hypercholesterolemia and atherosclerosis.

Animals↗
PubMed1990

[Therapeutic evaluation of combination therapy using C-425, human native immunoglobulin liquid preparation for i.v. administration, with antibiotics in severe infections in the field of internal medicine].

A novel human native immunoglobulin liquid preparation for intravenous injection, C-425, was used in combination with antibiotics to study its efficacy, safety, and usefulness in 262 patients with severe infections which had not responded to antibiotic therapy of 3-day or more duration. As a result of the Committee judgement, 12 of the 262 patients were excluded from this study; 87 were included only in safety analysis; 163 (62.2%) were included in efficacy, safety, and usefulness analyses (complete inclusion). The complete analysis of 163 patients consisted of 93 patients (57.1%) with suspected septicemia, 33 (20.2%) with pneumonia, and 18 (11.0%) with septicemia. Eighty percent or more of the patients had severe underlying diseases such as leukemia and malignant lymphoma. Clinical efficacy of C-425 was judged by the doctors in charge to be "excellent" or "good" in 49.1% of the total cases. The rate of effectiveness was calculated at 74.8% when "excellent", "good" and "fair" cases were all included. Similarly, the rate of effectiveness calculated from the results of Committee judgment was 53.4% when "excellent" and "good" cases were included, and 68.7% when "excellent", "good" and "fair" cases were included. Microbiological assessment was conducted in 19 patients. Causative organisms were eliminated in 11 patients, decreased in number in 1, persisted in 5, and replaced in 2. The rate of elimination was 57.9%. Side effects appeared in 6 of 250 patients (2.4%). It was judged that 3 patients (1.2%) of the 6 were affected by the drug or suspected to be affected, but they were not considered clinically important. Hepatic disfunction was found in 4 patients (1.6%) of the 250; but it was not clarified whether this was related to the drug. From these results, C-425 was considered to be an effective and very safe drug for treating severe internal infections.

Adolescent↗
PubMed1990

Secondary structure of the human T-cell leukemia virus type 1 rex-responsive element is essential for rex regulation of RNA processing and transport of unspliced RNAs.

Rex protein of human T-cell leukemia virus type 1 (HTLV-1) induces cytoplasmic expression of unspliced gag/pol mRNA and singly spliced env mRNA and thus is essential for replication of the virus. This regulation requires a cis-acting rex-responsive element (RXE), located in the 3' region of the viral RNA. By external deletion, we have identified RXE composed of 205 nucleotides. The secondary structure of RXE was confirmed by studies on its susceptibility to nuclease digestions to consist of four stem-loops and a long stretch of stem structure. Substitution and deletion mutations revealed that two regions of the stem-loops and their secondary structures are essential for rex regulation. Similar secondary structures were found in the corresponding regions of HTLV-2, bovine leukemia virus and human immunodeficiency virus. Furthermore, a sequence of 11 nucleotides in the RXE was found to be conserved in the secondary structures of HTLV-1, HTLV-2, and bovine leukemia virus. These observations suggest that the secondary structure as well as the conserved sequence may be important in expression of unspliced RNA even with diverged sequences as observed in these viruses.

Base Sequence↗
PubMed1990

Spontaneous release of angiotensin converting enzyme and interleukin 1 beta from peripheral blood monocytes from patients with rheumatoid arthritis under a serum free condition.

Angiotensin converting enzyme (ACE) and interleukin 1 activities were assayed simultaneously in the serum free medium from the unstimulated peripheral blood monocytes from 32 patients with rheumatoid arthritis (RA), 11 patients with osteoarthritis, and 25 normal controls matched for age and sex. Angiotensin converting enzyme activity was raised in most (29/32) patients with RA and interleukin 1 activity (most of which was interleukin 1 beta) was enhanced in 11/32 patients with RA, while monocytes from only two patients with osteoarthritis, but from none of the controls, secreted a small amount of ACE alone in the culture condition. Monocytes from patients with early RA (disease duration less than 3 years) released significantly more ACE and interleukin 1 than those from late stage RA (disease duration greater than or equal to 3 years).

Adult↗
PubMed1990

Effect of exogenous apo E on the cellular binding of lipoproteins.

It is well known that apolipoprotein E (apo E) has a significant role in the metabolism of plasma cholesterol through receptor-mediated endocytosis of lipoproteins containing apo B 100. We have reported that intravenous administration of apo E increases the clearance of lipoproteins containing apo B 100, resulting in reduced plasma cholesterol levels in WHHL rabbits. In the present study, we investigated the effects of exogenous apo E on lipoprotein binding to cell surface receptors. Lipoproteins were enriched in apo E by the incubation with purified apo E. Among lipoproteins enriched in apo E, VLDL and intermediate-density lipoprotein demonstrated higher binding affinity to cell surface receptor on fibroblast than respective unmodified lipoproteins. In competitive binding study, VLDL enriched by apo E (VLDL + E) completely suppressed 125I-LDL binding to human skin fibroblasts and showed the greatest binding activity among different lipoprotein classes, whereas both VLDL and LDL incompletely suppressed a binding of 125I-VLDL + E. This result indicated that apo-E-rich VLDL can bind not only to LDL receptor but to binding sites other than LDL receptors.

Animals↗
PubMed1990

Molecular cloning of gene sequences from rat heart rapidly responsive to pressure overload.

Although pressure overload induces cardiac hypertrophy and reexpression of contractile protein isogenes, the molecular mechanism of both is not well understood. We demonstrated the early change in the translational activity of specific cardiac messenger RNA by two-dimensional gel electrophoresis of in vitro translational products. A total of over 400 translational products were detected by fluorography, and the relative predominance of eight species was increased by pressure overload whereas that of two translational products was decreased. We cloned four pressure-overload-responsive complementary DNA clones, pPO-1, -4, -5, and -6, by differential dot blot hybridization. Two clones were increased from the early period after the imposition of pressure overload; the other two were decreased. The expression pattern of each complementary DNA clone in the pressure-overloaded hearts was similar to that in fetal hearts. Pressure overload also induced the additional messenger RNA, which hybridized with pPO-4. This mRNA was also recognized in fetal, neonatal, and adult spontaneously hypertensive rat hearts. The induction of this transcript by pressure overload was not suppressed but, rather, stimulated by cycloheximide. These results suggest that there are some genes that rapidly respond to pressure overload and that may play some role in the development of cardiac hypertrophy.

Acute Disease↗
PubMed1990

Messenger RNA levels of guanine nucleotide-binding proteins are reduced in the ventricle of cardiomyopathic hamsters.

The expression of guanine nucleotide-binding protein (G-protein) genes (Gs alpha, Go alpha, Gi alpha 1, Gi alpha 2, and Gi alpha 3) was examined in the ventricle of cardiomyopathic Syrian hamsters of the Bio14.6 strain (10-35 weeks old). Northern blot analysis of total cellular RNA revealed that all G-protein genes except Gi alpha 1 were expressed in the ventricle of Syrian hamsters. Gs alpha and Gi alpha 2 genes were abundantly expressed. The expression levels of the Gs alpha and Gi alpha 2 messenger RNAs in Bio14.6 ventricles were lower than the levels in ventricles of the F1B hamster strain; the abundance of Go alpha and Gi alpha 3 messenger RNAs did not change markedly. Moreover, the messenger RNA levels of Gs alpha and Gi alpha 2 decreased as the stage of cardiomyopathy progressed. Since G-proteins are linked to adenylate cyclase, these alterations of G-protein messenger RNA levels may be related to reduced contractility of cardiomyopathic heart.

Animals↗
PubMed1990

Expression of major histocompatibility complex class I antigen in murine ventricular myocytes infected with Coxsackievirus B3.

Evidence has accumulated that T cell-mediated autoimmunity plays an important role in the pathogenesis of viral myocarditis. T lymphocytes are known to recognize antigen-presenting cells, such as virus-infected cells, being restricted by syngeneic major histocompatibility complex (MHC) antigens. To clarify in more detail the immunological mechanisms involved, we induced acute viral myocarditis in C3H/He mouse ventricles with coxsackievirus B3 (CVB3) and examined, by immunofluorescence, the expression of MHC class I and II antigens, previously reported not to be expressed by normal cardiac myocytes. Furthermore, to confirm the expression of MHC class I (H-2Kk) antigens at the cellular level, we treated cultured cardiac myocytes with interferon gamma and examined the antigen expression by immunofluorescence and Northern blot hybridization, using an antisense RNA probe for MHC messenger RNA. Our observations demonstrated 1) CVB3-induced myocarditis resulted in the enhanced expression of MHC class I (H-2Kk) gene product on the surface of cardiac myocytes but low or undetectable levels of MHC class II or H-2Dk gene products, and moderate focal transient (days 5-7) expression of both MHC class I (Kk + Dk) region gene products and MHC class II antigens were induced on capillary endothelial cells; 2) murine fetal cardiac myocytes cultured in vitro in the presence of interferon gamma similarly were shown to express marked levels of MHC class I (H-2Kk) but low to undetectable levels of the H-2Dk gene product; however, weak to moderate MHC Class II antigens were expressed by these cultured myocytes; and 3) the expression of MHC antigens in cardiac myocytes was modulated at the transcriptional level.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Analysis of HLA antigens in patients with diffuse panbronchiolitis.

A new clinicopathologic entity, diffuse panbronchiolitis, was recently reported in Japan. This disorder is characterized by recurrent sinopulmonary infection and respiratory bronchiolitis. We identified cases of familial diffuse panbronchiolitis and found that many siblings of the patients had paranasal sinusitis. Because of this, we performed HLA analysis of the patients with diffuse panbronchiolitis. In HLA Class I and Class II antigens, Bw54 significantly increased (frequency: 63.2%; RR = 13.30; corrected p value less than 1.08 x 10(-10], whereas Cw1 and MC1 (a new HLA-DR-related antigen) slightly increased. These increases might be explained by the fact that these two antigens, Cw1 and MC1, formed a haplotype with Bw54, which suggests that one or some of the genes controlling the susceptibility and/or immune responsiveness of diffuse panbronchiolitis might be located near HLA loci. In addition, Bw54, or its related haplotype, exists only in Japanese, Chinese, and Korean populations. This may explain why a similar disease had not been reported in the English literature.

Asian People↗
PubMed1990

Endothelin family in human plasma and cerebrospinal fluid.

To clarify whether endothelin may be present in human cerebrospinal fluid (CSF) and, if it exists, to compare its molecular forms with those of endothelin in human plasma, we analyzed pooled human CSF and plasma by high performance liquid chromatography with specific enzyme immunoassays for each endothelin peptide. Of the four human endothelin peptides hitherto identified, big endothelin-1 was the major molecular form of endothelin present in human CSF. In addition, there was a small but significant amount of endothelin-1 and endothelin-3 in CSF, while endothelin-2 was not detectable. Similarly, big endothelin-1, endothelin-1, and endothelin-3 were identified in human plasma. Although big endothelin-1 was the most abundant, a substantial amount of endothelin-1 and endothelin-3 was found in plasma with a resultant lower molar ratio of big endothelin-1 to endothelin-1 than in CSF. In all CSF samples from 17 patients requiring diagnostic lumbar puncture or lumbar anesthesia, endothelin was detectable, with a preponderance of big endothelin-1 relative to endothelin-1 and endothelin-3. The mean concentrations of endothelin-1 and endothelin-3 in simultaneously collected plasma were significantly (P less than 0.01) higher than those in CSF, while there was no significant difference between the mean big endothelin-1 concentration in plasma and that in CSF. There was no significant correlation among concentrations of big endothelin-1, endothelin-1, and endothelin-3 in each paired sample. These results indicate that endothelin is present in human CSF that is differently processed from endothelin in vascular endothelial cells and suggest a possible role for endothelin as a modulator of neuronal functions.

Adult↗
PubMed1990

A functional retinoic acid receptor encoded by the gene on human chromosome 12.

A cDNA clone derived from a human hepatocellular carcinoma has been isolated on the basis of homology to the alpha human retinoic acid receptor (RAR alpha) gene. Expression of this cDNA produces a high affinity nuclear binding protein for retinoic acid. The product of this clone when expressed in transfected cells is able to activate transcription of a reporter plasmid through specific DNA sequences in response to the addition of retinoic acid to the medium. Dose-dependent profiles upon trans-activation of the reporter indicate that apparent sensitivity to retinoic acid of this protein is approximately 10-fold higher than that of human RAR alpha and is comparable to that of the second human RAR, RAR beta. This gene has been mapped to human chromosome 12, which is distinct from those coding for either alpha or beta RAR, and thus encodes a third human RAR.

Amino Acid Sequence↗
PubMed1990

Molecular mechanism of cardiac hypertrophy.

Pressure overload induces cardiac hypertrophy and reexpression of contractile protein isogenes. To ascertain the molecular mechanism of these events, we examined the expression of cellular oncogenes and the early change in the translational activity of specific cardiac mRNA by two-dimensional gel electrophoresis of in vitro translational products. Pressure overload increased the expression levels of c-fos, c-myc, and c-Ha-ras genes. The relative predominance of 8 species out of over 400 translational products was increased by pressure overload while that of 2 translational products was decreased. We cloned four pressure-overload-responsive cDNA clones by differential dot blot hybridization. The expression pattern of each cDNA clone in the pressure-overloaded hearts was similar to that in fetal hearts. To examine whether mechanical stimuli directly induce specific gene expression in the heart, we cultured rat neonatal cardiocytes in elastic silicone dishes and stretched these adherent cells. Myocytes stretching stimulated amino acid uptake and expression of the c-fos gene, which was blocked by protein kinase C inhibitors. These results suggest that there are some early responsive genes in cardiac hypertrophy and that mechanical loading directly stimulates gene expression possibly via protein kinase C activation.

Amino Acids↗
PubMed1990

Serum concentration of soluble interleukin-2 receptor as a sensitive parameter of disease activity in sarcoidosis.

We investigated the clinical value of measuring serum concentrations of soluble IL-2R in monitoring sarcoidosis. Serum concentrations of soluble IL-2R were measured in 70 patients with sarcoidosis. The mean value for active untreated sarcoidosis was 1,143 +/- 509 U/ml, while the normal range in 97 healthy control subjects was 80 to 300 U/ml. The mean value for active untreated sarcoidosis was significantly higher than that for dormant disease (353 +/- 183 U/ml) or that for corticosteroid-treated patients (380 +/- 151 U/ml). Serial changes in serum soluble IL-2R level were studied in cases of spontaneous remission or in corticosteroid-treated patients; a good correlation was noted between the changes in serum level of soluble IL-2R and clinical status. A positive correlation was noted between serum concentration of soluble IL-2R and serum ACE activity. These data confirmed that measurement of serum concentration of soluble IL-2R could be used in monitoring the disease activity in sarcoidosis.

Adult↗
PubMed1990

The release of hepatic triglyceride lipase from rat monolayered hepatocytes in primary culture.

The release of hepatic triglyceride lipase from cultured rat hepatocytes and its hormonal regulation were studied. The activity of lipase released into the medium in the presence of heparin was increasing for 24 hours on the 2nd day of culture. The activity in the absence of heparin was only 10% of that in the presence of heparin. When hepatocytes were cultured with anti-hepatic triglyceride lipase IgG, the lipase activity was suppressed by 92%. The results suggest that the enzyme released into the culture medium is identical to hepatic triglyceride lipase which can be released only in the presence of heparin, the mode of release being similar to that of lipoprotein lipase from adipocytes. The addition of colchicine and monensin to the medium resulted in the inhibition of lipase secretion by 20% and 61%, respectively. Insulin enhanced lipase activity only 20%, whereas dexamethasone suppressed the activity by 44%. These data indicated that hepatic triglyceride lipase is secreted and released from hepatocytes in the presence of heparin and its secretion is regulated by hormones.

Animals↗
PubMed1990

Changes in thyroglobulin release-stimulating activity (Tg-RSA) in immunoglobulin G from patients with Graves' disease during therapy with thionamide drug.

We have reported previously a new method for detecting thyroglobulin release stimulating activity (Tg-RSA) by human thyroid monolayer cells in IgGs from Graves' patients. We report here changes in Tg-RSA in sera of patients during treatment with thionamide drug. Nineteen untreated patients had their Tg-RSA, TSAb, TBII and serum Tg concentration (STg) followed up. Before treatment, Tg-RSA and TSAb were positive in all 19 patients. Three of them were TBII negative. During treatment with thionamide, of 16 patients who had positive Tg-RSA, TSAb and TBII before treatment, 6 patients continued so during the period of observation. Of the remaining 10 patients, 8 became TBII negative. TSAb only was found negative in one patient and Tg-RSA only declined to negative in another patient. Three patients whose TBII was initially negative, were observed to be negative in all three indicators after treatment. STg was higher than normal in all patients before therapy and changes in Tg-RSA in almost all patients were parallel with those in STg during treatment. From the observation during treatment with thionamide, our results suggest that Tg-RSA in Graves' patients appears to have similar properties to TSAb.

Amides↗
PubMed1990

Increased liver glucose-transporter protein and mRNA in streptozocin-induced diabetic rats.

The effect of insulin-deficient diabetic states on the rat liver glucose-transporter (L-transporter isoform) protein and mRNA levels were studied. Rats were injected with 65 mg/kg streptozocin to induce diabetes and were maintained for 10 days and then treated with or without insulin for the next 5 days. The L-transporter isoform with apparent Mr of 55,000 was observed to be increased approximately twofold in the membranes from liver homogenates of diabetic rats compared with control rats when assessed by Western blot analysis with an anti-peptide antibody directed against rat L-transporter isoform. Insulin treatment of diabetic rats decreased the amount of L-transporter isoform protein toward levels observed in nondiabetic rats. Northern blot analysis demonstrated similar alterations in the rat L-transporter isoform mRNA that paralleled the changes observed in the L-transporter isoform protein. The increased levels of the L-transporter isoform protein and mRNA in diabetic rats are in marked contrast to the effects of insulin deficiency in rat adipocytes, which specifically decrease the amount of the adipocyte glucose-transporter isoform protein and mRNA. These results suggest that glucose-transporter isoforms in rat liver and adipocytes are regulated by different mechanisms and that an increased synthesis of the L-transporter isoform may contribute to the increased glucose output that occurs from the liver during insulin deficiency.

Amino Acid Sequence↗
PubMed1990

Immunological detection of phosphotyrosine-containing proteins in rat livers after insulin injection.

Tyrosine-phosphorylated proteins in Triton X-100-solubilized fractions of rat livers were examined by immunoblotting with anti-phosphotyrosine antibodies. After 2 min of insulin injection via the portal vein into livers, three major bands of 170,000, 140,000, and 95,000 Mr were stimulated. Because the incubation of nitrocellulose membrane with anti-phosphotyrosine antibodies in the presence of 40 mM phosphotyrosine completely abolished these bands, the anti-phosphotyrosine antibodies appear to recognize the phosphotyrosine residues of these proteins. Insulin injection (2-2000 micrograms) very quickly stimulated the tyrosine phosphorylation of these proteins in a dose-dependent fashion. In contrast, insulinlike growth factor I or epidermal growth factor injection had little effect in stimulating the tyrosine phosphorylation of these proteins. Because anti-insulin-receptor antibodies immunoprecipitated a tyrosine-phosphorylated 95,000-Mr protein, this protein must be the beta-subunit of the insulin receptor; i.e., the beta-subunit of the insulin receptor and two other proteins were phosphorylated at tyrosine residues in vivo by insulin injection. These data suggest that the tyrosine phosphorylation and tyrosine kinase activity of the insulin receptor may have important roles in in vivo insulin action.

Animals↗