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Biomedical subjects

M Sugi

Publications and source records attributed to M Sugi.

At least 19 recordsLinked to original sources
PubMed1992

Effects of alpha and beta adrenergic blockade on coronary arterial microvessels in the beating canine heart.

OBJECTIVE: The aim was to clarify the effects of alpha and beta adrenergic blockade on coronary arterial microvessels and to assess the role of alpha and beta adrenergic tone in normally beating hearts. METHODS: 47 anaesthetised open chest dogs were studied. The diameters of epicardial arterial microvessels were measured in beating hearts using an incident light fluorescence microscope equipped with a floating objective. Drugs were infused into the left anterior descending coronary artery keeping the heart rate and aortic pressure at control levels. To examine the effect of alpha adrenergic blockade, phentolamine (100 micrograms.kg-1) was given in the absence or presence of beta adrenergic blockade (propranolol 50 micrograms.kg-1). To examine the effect of beta adrenergic blockade, propranolol (50 micrograms.kg-1) or three doses of ICI 118,551 (a selective beta 2 antagonist, 0.1, 0.5, and 1.0 microgram.kg-1.min-1) was given. RESULTS: Coronary arterial microvessels were divided into three groups according to the control diameters (D) of small (D less than 100 microns), medium (100 less than or equal to D less than 200 microns) and large (D greater than or equal to 200 microns) groups. In the absence of beta adrenergic blockade, phentolamine significantly dilated all vessel groups: small +19.6 (SEM 5.6)%, medium +5.8(2.3)%, large +5.3(0.9)%. In the presence of beta adrenergic blockade, the vasodilator effect of phentolamine was completely abolished. Propranolol constricted all vessel groups: small -3.6(1.1)%, medium -4.8(1.0)%, large -3.5(1.0)%. ICI 118,551 significantly constricted the large vessel group [-2.5(0.6)%] at the mid dose, and the medium and large vessel groups [medium -3.1(0.8)%, large -3.5(1.3)%] at the highest dose. CONCLUSIONS: These data indicate that (1) the vasodilator effect of phentolamine is induced by beta adrenergic stimulation; (2) resting alpha adrenergic tone of coronary arterial microvessels is minimal in normally beating hearts, and (3) resting beta adrenergic tone may play a physiological role in coronary arterial microvessels, and beta 2 adrenergic tone predominates in arterial microvessels greater than 100 microns in diameter.

Adrenergic alpha-Antagonists↗
PubMed1992

Performance of an enzyme-linked immunosorbent assay system for antibodies to hepatitis C virus with two new antigens (c11/c7).

We developed an enzyme-linked immunosorbent assay (ELISA) system for antibodies to the hepatitis C virus (HCV), using two new recombinant antigens (c11 and c7) derived from the HCV genome. The performance of this ELISA system (Imucheck HCV Ab) was examined. The CV values for both intra-assay precision and reproducibility of identifying HCV antibody in the panel sera ranged from 3.5% to 6.4%. The blood elements in serum and anticoagulants did not interfere in this ELISA system. The specificity of Imucheck HCV Ab to samples from patients with non-A, non-B (NANB)-type chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma was 93.7%, 93.5%, and 81.4%, respectively. These results are more sensitive than those obtained by the first-generation anti-HCV ELISA system. In the samples from patients with NANB-type acute hepatitis, Imucheck HCV Ab enabled detection of HCV antibodies at an early stage. This system increased the sensitivity for blood donor screening and for monitoring patients with acute hepatitis.

Antibody Specificity↗
PubMed1990

An enzyme-linked immunosorbent assay (ELISA) for adenosine 3',5'-cyclic monophosphate (cAMP) in human plasma and urine using monoclonal antibody.

A reliable and sensitive ELISA for cAMP in human plasma and urine is described, using a monoclonal antibody and a 96 well microtiter plate. Succinyl cAMP is conjugated to human serum albumin and adsorbed to the ELISA plate, giving an immobilized antigen approach which simplifies subsequent assay procedures. As low as 1.56 fmol/well of both plasma and urinary cAMP is measurable. Recoveries of added cAMP in plasma and urine were from 99% to 109%. Intra-assay coefficients of variation were less than 6.1% for plasma and 7.0% for urine samples. Inter-assay coefficients of variation for plasma and urine samples were less than 8.9% and 9.5%, respectively. There was a good correlation between the values obtained by ELISA and radioimmunoassay (RIA) (plasma: r = 0.94, n = 66; urine: r = 0.98, n = 64; nephrogenous cAMP: r = 0.96, n = 51).

Antibodies, Monoclonal↗
PubMed1990

Monoclonal antibodies to endothelin: application for sandwich immunoassays.

We established 16 monoclonal antibodies (MAbs) to endothelin (ET), a novel and potent vasoconstrictor. They were classified into two groups: eight of them reacted with the C-terminal portion of ET, and the other eight reacted with the non-C-terminal portion. We constructed the sandwich enzyme linked immunosorbent assays (ELISAs) using a combination of a MAb belonging to the former with that belonging to the latter, and could detect about 400 pg/ml of ET.

Animals↗
PubMed1989

High induction of poly(ADP-ribose) polymerase activity in bleomycin-resistant HeLa cells.

Poly(ADP-ribose) polymerase activity was measured in bleomycin (BLM)-resistant HeLa (HeLa-BLMr) and the parental HeLa cells after BLM treatment. HeLa-BLMr cells, which had been subcultured in growth medium containing 1 micrograms/ml of BLM, showed a 3.75-fold higher enzyme activity than did HeLa cells, but this activity was decreased to the same level as that of HeLa cells after 48 h of BLM-free cultivation. When HeLa and HeLa-BLMr cells after a 48-h cultivation in BLM-free growth medium were treated with BLM, the enzyme activity was induced at a higher level (2.5-3.8 times) in HeLa-BLMr than in HeLa cells and was inhibited markedly in HeLa-BLMr and slightly in HeLa cells by nicotinamide, an inhibitor of this enzyme. The BLM-induced cell killing by nicotinamide was highly potentiated (about 18 times) in HeLa-BLMr as compared to HeLa cells.

Bleomycin↗
PubMed1989

[Clinical application of immunoassays for cardiac myosin light chains].

We developed four types of immunoassays for cardiac myosin light chains (LC), which are two radioimmunoassays (RIA) for canine and human LC, and an immunoradiometric assay (IRMA) and an enzyme-linked immunosorbent assay (ELISA) for human LC. The first two assays make use of polyclonal antibodies and the last two use monoclonal antibodies. By using these immunoassays, we studied the release of cardiac LC into the serum following acute myocardial infarction (AMI). In experimental AMI in dogs, cardiac LC appeared in the serum within 4-12 hours, reached the maximum at 2-5 days and returned to normal at 7-10 days. This long time-course was suggested due to the continuous liberation of LC from the infarcted myocardium on the basis of a quick disappearance rate of LC from the circulation. The peak LC values were found to correlate well with the histological infarct size. Similar results were also obtained regarding the time-course of circulating LC in clinical patients with AMI. Thus LC measurement seems useful for diagnosis of AMI as well as for estimating the extent of myocardial damage. We also developed an IRMA and an ELISA for human LC by using anti-human LC monoclonal antibodies for a more rapid LC assay and for a consistent supply of antibodies. These assays showed sufficiently high sensitivities to measure 1-100 ng/ml of serum LC. Especially, serum LC can be assayed within 2.5 hours by our ELISA. Such progress in immunoassays for cardiac LC has made the measurement of LC an important laboratory test for the diagnosis of AMI.

Animals↗
PubMed1988

Establishment of three bleomycin-resistant human carcinoma cell lines and their cross-resistance to other antitumor agents.

Three bleomycin-resistant (BLMr) human carcinoma cell lines (HeLa-BLMr, KB-BLMr, and Hepd-uvBLMr) were established in culture by progressively increasing the concentration of bleomycin (BLM). HeLa-BLMr and KB-BLMr were obtained after 5 and 2 months of incubation with BLM, whereas the establishment of Hepd-uvBLMr required 3 months of incubation with BLM after ultraviolet treatment. These cells have been successfully subcultured for more than 150 passages during more than 2 years in the presence of 1 microgram/ml of BLM. The degrees of BLM resistance were 20-fold, 11.6-fold, and 186-fold for HeLa-BLMr, KB-BLMr, and Hepd-uvBLMr, respectively, and the resistant phenotype of both HeLa-BLMr and Hepd-uvBLMr was stable when they were cultured for 30 passages in BLM-free medium, but unstable in KB-BLMr. Although each cell line exhibited cross-resistance to 3 to 5 other antitumor agents including peplomycin, combined use of BLM with a polyene antibiotic, a calcium channel blocker, or a poly(ADP-ribose) polymerase inhibitor overcame the BLM resistance in vitro to various degrees.

Aged↗
PubMed1988

Further characterization of bleomycin-resistant HeLa cells and analysis of resistance mechanism.

Bleomycin (BLM)-resistant HeLa cells (HeLa-BLMr), which have been subcultured for more than 150 passages during over 2 years in the presence of 1 micrograms/ml of BLM and stably possess a 20-fold-increased BLM-resistance in vitro, were further characterized. The nude mouse tumors produced by HeLa-BLMr were significantly less sensitive (P less than 0.005-0.01) to BLM administration than those produced by HeLa cells, and the cells primarily cultured from nude mouse tumors of HeLa-BLMr and transplanted serially 5 times in the absence of BLM also exhibited a similar degree of BLM resistance to that of HeLa-BLMr cultured in BLM-containing medium. The BLM-resistance mechanism of HeLa-BLMr was partially analyzed. The cells showed about 40% decreased accumulation and 2-3 times reduced retention of [3H]peplomycin, a novel BLM analog, as compared to HeLa cells, but the BLM-hydrolase activity was at almost the same level as that of HeLa cells when determined by HPLC. Furthermore, alkaline sucrose gradient analysis of cellular DNA after BLM treatment revealed that the damaged DNA was more efficiently repaired in HeLa-BLMr than in HeLa cells. These results suggest that decreased drug accumulation and retention, and elevated DNA repair activity are the main mechanism of BLM resistance in HeLa-BLMr.

Animals↗
PubMed1988

Heterogeneity of beta-type myosin isozymes in the human heart and regulational mechanisms in their expression. Immunohistochemical study using monoclonal antibodies.

To investigate the existence of heterogeneity of beta-type myosin isozymes (HC beta) in human hearts, immunohistochemical studies using monoclonal antibodies (MoAbs) raised against human ventricular myosin heavy chains were performed. Two types of MoAbs recognized some muscle fibers in the atrium, whereas both reacted with all ventricular muscle fibers. Since atrial muscle fibers reactive with each MoAb were found to be clearly different, the existence of two immunologically distinct HC beta (beta 1, and beta 2) was suggested in the atrium. By using affinity chromatography, two molecular variants of HC beta were isolated from the bovine atrium, and differences in the primary structure of beta 1 and beta 2 were confirmed by analysis of peptides produced by chymotryptic digestion. In pressure-overloaded human atria, myofibers containing beta 1 and/or beta 2 increased in accordance with decrement of myofibers containing alpha-type myosin isozyme (P less than 0.01). But they differed in expression during the developmental stage, since beta 2 did not exist in the early embryonic bovine heart, but beta 1 did. Thus, there are two distinct HC beta whose expression is regulated by at least two factors: pressure overload and developmental stage.

Adult↗
PubMed1987

Monoclonal antibody to human beta interferon: characterization and application.

Seven stable mouse hybridomas secreting monoclonal antibodies to human fibroblast beta interferon (IFN-beta) were isolated, all seven of which belonged to IgGl subclass and kappa type. While neutralizing the antiviral activity of human fibroblast IFN-beta, they failed to neutralized both that of human IFN-alpha and human IFN-gamma. These monoclonal antibodies neutralized the antiviral activity of human fibroblast IFN-beta but not that of human IFN-alpha and IFN-gamma. Two of the seven monoclonal antibodies, YSB-1 and YSB-2, showed particularly high neutralization titers in the ascitic fluid. Monoclonal antibodies were purified from cultures of hybridoma grown in a serum-free medium. The purified monoclonal antibodies, YSB-1(5 micrograms/ml) and YSB-2(1 microgram/ml), neutralized IFN-beta from 10EU/ml to 1EU/ml. Human fibroblast IFN-beta was purified to 3.5 X 10(7) IU/mg protein (1.0 X 10(8) IU/mg protein in the peak fraction) by the monoclonal antibody (YSB-2) affinity column chromatography, whereas human recombinant IFN-beta obtained from E.coli was also purified to 6.5 X 10(7) IU/mg protein (1.1 X 10(8) IU/mg protein in the peak fraction) by the monoclonal antibody (YSB-1) affinity column chromatography.

Animals↗
PubMed1987

Early plaster treatment for fractures of the femoral shaft in childhood.

A protocol for the treatment of fractures of the middle third of the femur by the early application of a hip spica has been evaluated in 191 children aged 10 years or less. Children without other injuries spent only a few days in hospital for the application and later removal of the spica. At all ages, anterior angulation of less than 20 degrees and valgus angulation of less than 15 degrees were accepted at the one-week review. Acceptance of shortening varied with the age of the child and the stage of treatment, but was 10% or less of the femoral length at the time of spica removal. At late review leg-length discrepancy was rare and clinically insignificant. This method of treatment was simple and effective. It dramatically reduced the cost of care and freed a number of children's hospital beds.

Aftercare↗