Biomedical subjects
I Sakurabayashi
Publications and source records attributed to I Sakurabayashi.
[Abnormal Hb (hemoglobin)].
Explore the source record for details and available documents.
[Immunoglobulin G (IgG) and IgG subclass].
Explore the source record for details and available documents.
[Anaphylatoxins C3a, C4a, C5a].
Explore the source record for details and available documents.
Novel therapeutic strategy for atherosclerosis: ribozyme oligonucleotides against apolipoprotein(a) selectively inhibit apolipoprotein(a) but not plasminogen gene expression.
BACKGROUND: Because mechanisms of atherosclerosis by lipoprotein(a) [Lp(a)] have been postulated in the decrease in active transforming growth factor-beta conversion by decreased plasmin, selective decrease in apolipoprotein(a) [apo(a)] independent of plasminogen may have therapeutic values. Although antisense can decrease apo(a), its application may be difficult because of very high homology of apo(a) gene to plasminogen. Thus we used ribozyme strategy that actively cleaves targeted genes to selectively inhibit apo(a) expression. METHODS AND RESULTS: We constructed ribozyme oligonucleotides containing phosphorothioate DNA- and RNA-targeted kringle 4 of the apo(a) gene that showed 80% homology to plasminogen. Transfection of human apo(a) gene produced Lp(a) in medium of HepG2 cells, whereas Lp(a) could not be detected in control cells. Cotransfection of ribozyme and apo(a) gene resulted in the decrease in mRNA of apo(a) but not plasminogen. Moreover, marked decrease in Lp(a) was also observed in the medium transfected with ribozyme and apo(a) gene compared with apo(a) gene alone (P<0.01), whereas there was no significant change in plasminogen level between ribozyme-transfected and control cells. Incubation of human vascular smooth muscle cells (VSMC) with conditioned medium from apo(a)-transfected HepG2 cells resulted in a significant increase in VSMC number, whereas addition of conditioned medium from cells cotransfected with ribozyme oligonucleotides and apo(a) gene resulted in no VSMC growth (P<0.01). DNA-based control oligonucleotides and mismatched ribozyme oligonucleotides did not have an inhibitory effect on Lp(a) production. CONCLUSIONS: Overall, our data revealed that transfection of ribozyme against the apo(a) gene resulted in the selective inhibition of the apo(a) but not the plasminogen gene, providing novel therapeutic strategy for treatment of high Lp(a), a risk factor for atherosclerosis.
A case of multiple myeloma IgG(lambda)type with low molecular weight kappa light chain.
Explore the source record for details and available documents.
Stimulatory effect of lipoprotein (a) on proliferation of human mesangial cells: role of lipoprotein (a) in renal disease.
As lipoprotein (a) [Lp(a)] abnormalities would accelerate glomerular injury, we studied the effect of Lp (a) on proliferation of cultured human mesangial cells (MC). Transfection of human apo (a) gene into human hepatoma cells, HepG2 cells, producing human apo B, resulted in the formation of Lp (a), while no Lp (a) was detected in control cells. In contrast, free apo (a) was detected in the medium of apo (a)-transfected MC. Incubation of cultured medium of HepG2 cells transfected with apo (a) gene with MC resulted in a significant increase in cell number compared to control (P<0.01). In contrast, little effect of transfection of apo (a) gene directly into MC on growth of MC was observed. Of importance, addition of LDL into the medium of MC transfected with apo (a) vector resulted in a significant increase in number of MC compared to control, whereas LDL did not show any effects on MC growth. As active TGF-beta was not detected in the medium of MC, and addition of neutralizing anti-TGF-beta antibody did not alter growth of MC, Lp (a) stimulated growth of MC via the independent mechanisms from the inhibition of TGF-beta activation.
Changes in immune-endocrine response after surgery.
The authors evaluated the relationship between hormonal and cytokine responses after surgery. Patients who underwent thoracic oesophagectomy (O group; n = 7), pulmonary lobectomy (P group; n = 5), modified mastectomy (M group; n = 5) and laparoscopic cholecystectomy (LC group; n = 7), were randomly selected. Circulating neutrophil and lymphocyte numbers were assayed. Changes in the concentration of the hormones [adrenocorticotrophic hormone (ACTH), cortisol, and antidiuretic hormone (ADH)] and cytokines [tumour necrosis factor alpha (TNF-alpha), interleukin 1 beta (IL-1 beta), IL-6, and IL-10] were analysed. In O and P groups, neutrophils were still seen on post-operative day (POD) 3, while the leukocyte counts of M and LC groups returned to normal. The number of lymphocytes significantly decreased on POD1 and POD3 only after oesophagectomy. The pattern of hormonal levels was consistent in all groups. While TNF-alpha and IL-1 beta were undetectable in the peripheral blood, the concentration of IL-6 and IL-10 increased in O and P groups, but not in M and LC groups. The degree of lymphocytepenia and neutrophilia correlated well with the extent of surgical trauma.
Elevated serum level of thioredoxin in patients with hepatocellular carcinoma.
Thioredoxin (TRX) is known to contain an active site with a redox-active disulfide and has various biological activities. The objective of the present study was to investigate whether circulating TRX levels are elevated in patients with chronic hepatitis (CH) or liver cirrhosis (LC) and hepatocellular carcinoma (HCC). An anti-TRX monoclonal antibody and polyclonal antibodies that specifically recognize TRX, were generated and used for the development of an ELISA system to measure TRX levels in human serum. The geometric mean and its 95% confidence interval of serum level of TRX in healthy volunteers was 81.75 ng/ml (74.60-89.59 ng/ml). The serum level of TRX in LC/CH patients without HCC was 80.87 ng/ml (69.66-93.88 ng/ml). The value was not statistically different from that in serum from normal volunteers (p=0.69). In contrast, the serum level of TRX in patients with HCC was 147.35 ng/ml (125.53-172.96 ng/ml), which was significantly higher when compared with the level in serum of normal volunteers (p<0.001) and in serum of LC/CH patients without HCC (p<0.001). In four patients with HCC, the initially high level of serum TRX (>150 ng/ml) decreased below 150 ng/ml after surgical removal of the tumor. The data reported herein revealed that patients with HCC had a significantly elevated serum level of TRX, suggesting that measurement of serum of TRX might be a useful clinical parameter when HCC is suspected.
Conditioned medium from HepG2 cells transfected with human apolipoprotein(a) gene stimulates growth of human vascular smooth muscle cells: effects of overexpression of human apolipoprotein(a) gene.
Lipoprotein(a) [Lp(a)] is well known to stimulate growth of vascular smooth muscle cells (VSMCs), resulting in atherosclerosis. Its mechanism is postulated to be decreased in active transforming growth factor (TGF)-beta. However, the exact mechanisms and cellular processing from apolipoprotein(a) [apo(a)] to Lp(a) have not yet been clarified because no cultured cells producing apo(a) are available. Therefore, it is necessary to establish apo(a)-producing cells to study the role of apo(a). We evaluated the effects of overexpression of human apo(a) gene on human aortic VSMC growth. First, we tested whether transfection of apo(a) gene into human hepatoma cells, HepG2 cells, producing human apoB resulted in the formation of Lp(a). Transfection of apo(a) gene into HepG2 cells resulted in detectable levels of Lp(a) in the medium, as assessed by ELISA and Western blot, whereas no Lp(a) was detected in the medium of HepG2 cells transfected with control vector and untransfected HepG2 cells. Expression of apo(a) mRNA was also confirmed by reverse transcription-polymerase chain reaction. In contrast, Western blotting showed a single band detected by specific anti-apo(a) antibody, but not anti-apoB antibody, in the medium of apo(a)-transfected VSMCs. These results demonstrate that Lp(a) can be formed from apo(a) on HepG2 cells, whereas transfection of apo(a) gene into VSMCs resulted in the production of apo(a) alone but not Lp(a). Next, we examined the biological effects of overexpression of apo(a) gene on growth of VSMCs and endothelial cells. Incubation of cultured medium of HepG2 cells transfected with apo(a) gene with human VSMCs or endothelial cells resulted in a significant increase in cell number compared with the conditioned medium of HepG2 cells transfected with control vector. In contrast, transfection of apo(a) gene directly into VSMCs caused no significant effect on VSMC growth. Therefore, we measured TGF-beta concentration in the conditioned medium of VSMCs. However, using ELISA, only latent but not active TGF-beta was detected in the medium of VSMCs. Moreover, addition of neutralizing anti-TGF-beta antibody did not alter VSMC growth. These results suggest that Lp(a) could stimulate growth of VSMCs via the independent mechanisms from the inhibition of TGF-beta activation. Overall, these data demonstrate that overexpression of apo(a) gene in cells producing apoB results in formation of Lp(a), resulting in a mitogenic action on human endothelial cells and VSMCs. These results provide new information to understand the mechanisms of the mitogenic action of Lp(a) and suggest the role of Lp(a) in the pathogenesis of atherosclerosis.
Serum lipoprotein lipase in healthy subjects: effects of gender and age, and relationships to lipid parameters.
Using serum samples obtained from normal individuals who had not received heparin injection, we investigated the relationship of lipoprotein lipase (LPL) to lipid and apolipoprotein concentrations in serum. For the measurement of LPL concentration, a highly sensitive enzyme-linked immunosorbent assay (ELISA) was developed, in which the lowest detection limit was 9 micrograms/L. The mean (SD) serum LPL concentration was 50.7 (14.9) micrograms/L (n = 240). It was lower in men [45.5 (14.0) micrograms/L in men and 56.0 (13.9) micrograms/L in women]. Serum LPL concentration correlated positively with high-density lipoprotein cholesterol (HDL-C, r = 0.549) and apolipoprotein AI (apoAI, r = 0.487), and inversely with triglycerides (r = -0.423). Our results suggest that serum LPL may be a factor in the modulation of HDL-C and triglyceride concentrations in normal subjects.
International Federation of Clinical Chemistry standardization project for the measurement of lipoprotein(a). Phase I. Evaluation of the analytical performance of lipoprotein(a) assay systems and commercial calibrators.
A secondary reference material for lipoprotein(a) is required to standardize the measurement of lipoprotein(a) in clinical laboratories worldwide. Towards this aim, the International Federation of Clinical Chemistry Working Group for the Standardization of Lipoprotein(a) Assays has initiated a standardization project involving a total of 33 diagnostic company and clinical chemistry laboratories from 12 countries. In Phase 1, the analytical performance of 40 lipoprotein(a) assay systems was evaluated by testing sera and manufactured lipoprotein(a) calibrator materials for precision, linearity, and parallelism. Twenty test systems were nonoptimized according to the results for a pooled serum, which tested nonlinear in 16 systems and imprecise in 4. Acceptable analytical properties and harmonization of lipoprotein(a) values were shown by some commercial calibrators, suggesting their possible use as reference materials. This study highlights the problems that currently occur for lipoprotein(a) measurement in existing assay systems.
[Introductory review of diagnostic approach to arteriosclerosis].
Investigation of the pathogenesis of arteriosclerosis and/or atherosclerosis has been progressed using molecular biology. New concepts have been developed and, receptors and substances have been found clinically and experimentally, which have led us to create new methods of evaluating or diagnosing the grade of atherosclerosis lesion. Dealing with the new concepts or knowledge in this symposium, this introductory paper describes an overview of pathogenesis of atherosclerosis, from which the new methods of evaluating or diagnosing lesion has been exploited. The injury to the endothelium leads to endothelial cell dysfunction, which initiates the acceleration of LDL oxidation and increases adherence of monocytes, macrophages and T lymphocytes, migrating subendothelially and causing large foam cells to develop because of lipid accumulation. Macrophages and platelets release many growth factors, which accelerate the growth of vascular smooth muscle cells, forming fibrous plaque. In these pathogenic processes of atherosclerosis, angiotensin II participates in releasing growth factor for cell proliferation and hepatocyte growth factor (HGF) participates in revascularization of the sclerotic lesion, suggesting a candidate marker for atherosclerosis. Hyperlipidemia and hypercoagulation are the major factors in advanced atherosclerosis. Using new methods to evaluate or diagnose lesions, further therapy and prevention for atherosclerosis will progress in future.
Regulatory effects of aggregated LDL on apoptosis during foam cell formation of human peripheral blood monocytes.
In order to investigate the mechanisms how modified lipoproteins enhance foam cell formation, we cultured peripheral blood monocytes with various stimulants and examined the effects of aggregated low-density lipoprotein (agLDL) on cell viability and lipid metabolism. AgLDL could completely inhibit phorbol ester-induced apoptosis, which was accompanied by intracellular cholesterol accumulation. Suppression of apoptosis-promoting proteases, ICE and CPP32, was observed in agLDL-treated cells. This indicates that agLDL accelerates foam cell formation through inhibition of apoptosis and enhancement of lipid accumulation in activated monocytes. By contrast, apoptosis was enhanced when monocytes were cultured with agLDL and M-CSF. Intracellular cholesterol accumulation was not significant in M-CSF treated cells. This suggests that M-CSF may act anti-atherogenic through apoptotic elimination of lipid-baring macrophages and enhanced lipid turnover. Our observation supports the novel hypothesis that regulation of apoptosis may play an important role in the development of atherosclerosis.
[Coding for clinical laboratory information].
The field of clinical laboratory tests is facing an increase in the number of test items as well as a corresponding diversification due to the demands of medical institutions as well as improvements in analytical techniques. To respond to this situation, medical institutions have been promoting systematization of their testing procedures; information exchange among the institutions has likewise expanded with the use of media such as on-line systems and internet. Standardization of interfaces has been proposed to secure a common framework compatible with different types of information. Some embodiments in this country includes; (1) Interface Standards on Clinical Laboratory Information For information exchange, the format and reporting comments used in the media systems were standardized under the sponsorship of The Medical Information System Development Center, with a publication issued on 1993. (2) Standardization of Laboratory Test Code Standardization of codes for information exchange has been established under the sponsorship of The Japan Society of Clinical Pathology (Laboratory Test Coding Committee), through the systematization of laboratory test code used in media systems. A publication entitled "Classification & Coding for Clinical Laboratory Tests (8th edition in 1992, 9th edition in 1994 and supplement in 1996)" has been issued. The system for "Classification & Coding for Clinical Laboratory Tests" is divided into 5 components; (1) analyte code, (2) identification code, (3) specimen code, (4) methodology code, and (5) data classification code. The Laboratory test codes are precisely classified by "(1) analyte code", and then are identified by combination of additional codes such as specimen and methodology codes. In this year, we are making a new easily-used-codes composed of 5 Arabic figures.