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Biomedical subjects

H Maeda

Publications and source records attributed to H Maeda.

At least 1,099 records · Page 61Linked to original sources
PubMed1986

[Studies on surface tension of amniotic fluid with special emphasis on evaluating fetal lung maturity].

In order to establish a simple and rapid test for the determination of fetal lung maturity, surface tension (ST) of lipid extracts prepared from amniotic fluid samples obtained from 54 women was measured by Wilhelmy's method. The patterns of ST were classified into three types. Type I: ST of 45 dyne/cm or more at 200 microliters of extract and 36 dyne/cm or more at 350 microliters. Type II: ST of 45 dyne/cm or more at 200 microliters and less than 36 dyne/cm at 350 microliters. Type III: ST less than 45 dyne/cm at 200 microliters. L/S ratio was 2 or more (greater than or equal to 2) in 7 of 23 cases (30.4%) with Type I patterns, 2 of 6 cases (33.3%) with Type II patterns, and 24 of 25 cases (96.0%) with Type III patterns. ST of mature amniotic fluid centrifuged for 10 min. at 5,000 X g and 10,000 X g was higher than ST of mature amniotic fluid centrifuged at 450 X g and 1,000 X g, but ST of immature amniotic fluid showed no significant difference in ST at different centrifugal forces. Contamination with meconium and blood was found to lower ST of immature amniotic fluid remarkably. ST of amniotic fluid lipid extract appeared to be a simple, rapid and reliable method for the assessment of fetal lung maturity.

Amniotic Fluid↗
PubMed1986

Enhanced colony formation of human hemopoietic stem cells in reduced oxygen tension.

In general, cell cultures, including hemopoietic stem cells, are produced in an atmosphere of various CO2 concentrations in air, although most cells in vivo proliferate and differentiate at lower oxygen tensions. We therefore investigated the effect of reduced oxygen tension on the in vitro colony growth of committed and multipotential hemopoietic progenitor cells from human bone marrow. All hemopoietic progenitor cells (CFU-mix, BFU-E, CFU-E, and CFU-GM) investigated showed enhanced colony growth at lower oxygen tension. CFU-E showed the highest enhancement, followed in order by BFU-E, CFU-mix and CFU-GM. At reduced oxygen tension, the sensitivity of early and late erythroid progenitor cells to erythropoietin was significantly increased, and this can be one of the mechanisms for the enhanced colony growth of erythroid progenitors. In the colony growth of CFU-GM, plating efficiency was also enhanced by the predominant increment of neutrophilic colonies. The lowering of oxygen tension would presumably reduce oxygen toxicity and result in the increased colony growth of human bone marrow stem cells, although the precise mechanisms of oxygen toxicity at the level of hemopoietic stem cells have yet to be elucidated. However, this clonal culture system, using a low oxygen tension, can be a useful means for elucidating the regulatory mechanisms involved in the proliferation and differentiation of hemopoietic progenitor cells in physiological and pathological conditions.

Bone Marrow↗
PubMed1986

[Pharmacokinetics of cefixime in patients with impaired renal function].

Cefixime (CFIX) was given orally in a single dose of 100 mg to 7 patients with varying degrees of impaired renal function (Ccr 12.0-56.7 ml/min) and serum concentrations and urinary excretion rates were measured with time for the first 24 hours by the bioassay method to investigate in vivo pharmacokinetics of the drug. The results obtained are summarized as follows. The mean peak serum concentration of CFIX in 3 patients with moderately impaired renal function (group I: Ccr greater than or equal to 30-less than 60 ml/min) was 2.04 micrograms/ml at 6 hours after dosing and gradually declined to 0.10 microgram/ml at 24 hours after dosing. The half-life was 4.15 hours. The mean peak serum concentration of CFIX achieved was 2.27 micrograms/ml at 8 hours after dosing in 4 patients with severely impaired renal function (group II: Ccr greater than or equal to 10-less than 30 ml/min) and the concentration of CFIX was 0.99 microgram/ml even after 24 hours. The half-life was prolonged to 11.05 hours. There was no great difference between groups I and II in the first 24-hour urinary excretion rates. However, the first 4-hour urinary excretion accounted for 2.14% of the administered dose of CFIX in group I but only 0.47% in group II. Urinary concentrations of CFIX peaked at 4-6 hours after dosing in both groups, and thereafter gradually decreased in group I. Whereas, they did not decline much in group II until 24 hours after dosing.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1985

Monoclonal antibodies with specific effects on partial activities of recA protein of Escherichia coli.

recA protein of Escherichia coli promotes a wide variety of DNA reactions in vitro. Specific effectors of recA protein should be very useful in elucidating the mechanisms of these complex reactions. Six mouse hybridoma clones that secreted class G immunoglobulins specific to recA protein were obtained in three cell-fusion experiments. Five IgGs were purified by affinity chromatography. These monoclonal antibodies were characterized by examining their effects on the single-stranded DNA-dependent ATPase activity, negatively superhelical double-stranded DNA-dependent ATPase activity, and an activity in pairing negatively superhelical closed circular double-stranded DNA and homologous single-stranded DNA-fragments to form D-loops. These IgGs inhibited all, some, or one of these three activities, and from the spectra of their inhibitory effects they were classified into four groups. This classification suggests that each of the monoclonal antibodies binds to one of at least four antigenic determinants on recA protein and specifically inactivates one or more of the active centers on the protein. These monoclonal antibodies will be useful in analyzing the complex reactions promoted by recA protein.

Adenosine Triphosphatases↗
PubMed1985

The platelet protein phosphorylation induced by a monoclonal antibody against human platelets (TP82).

In human platelets, a monoclonal anti-human platelet antibody (TP82) induced platelet aggregation and release of granules (i.e., serotonin, platelet factor 4, N-acetyl-beta-D-glucosaminidase). The release reaction occurred even in the absence of aggregation and was preceded by not only the protein phosphorylation, but the transient formation of endogenous diacylglycerol (DG). These results suggest that polyphosphoinositide breakdown plays an essential role in antibody-induced release of platelet granules.

Antibodies, Monoclonal↗
PubMed1985

Image enhancement in computerized tomography for sensitive diagnosis of liver cancer and semiquantitation of tumor selective drug targeting with oily contrast medium.

A new type of anticancer agent with an amphiphilic nature, poly(styrene-co-maleic acid)-conjugated neocarzinostatin (Smancs), was dissolved in lipid contrast medium Lipiodol (Smancs/Lpd, Gelbet Co., Paris, France). This medium was injected arterially and found to be an invaluable tool for highly sensitive computerized tomography (CT) image analysis of tumors. After the administration, CT images revealed high-density areas which corresponded to the location and size of liver cancer, the smallest being 4 mm in diameter. The deposition pattern of Smancs/Lpd in liver cancers by CT was classified into three types. In type A, Lipiodol was distributed relatively even in the tumor lesion, whereas in type B it was accumulated predominantly around the tumor's periphery although the central portion remaining low in density. A few cases exhibited type C pattern, which was a mixture of types A and B. Type A was found essentially in primary liver cancer, and types B and C in secondary liver cancer. Thus, the CT pattern was found to be useful for differential diagnosis. For a sufficient therapeutic effect, 0.08 ml of Smancs/Lpd per cm2 of the maximal CT cross-section of the tumor area was found to be necessary. As a routine protocol after Smancs/Lpd administration, CT scanning was recommended for primary liver cancer initially at 1 week and then once every month. Secondary liver cancer required more frequent CT follow-ups after the administration (on the third day, after 1 and 2 weeks, and every month) due to relatively rapid disappearance of the stain than in the primary liver cancer.

Aged↗
PubMed1985

Scavenger function of sinusoidal liver cells. Acetylated low-density lipoprotein is endocytosed via a route distinct from formaldehyde-treated serum albumin.

Chemically modified proteins such as acetylated low-density lipoprotein (acetyl-LDL) and formaldehyde-treated serum albumin (f-Alb) infused intravenously are known to undergo receptor-mediated endocytosis by sinusoidal liver cells, major intravascular scavenger cells in vivo. The aim of the present study was to elucidate whether the endocytic uptake of acetyl-LDL and f-Alb is mediated by the same receptor or not. Experiments on the binding of 125I-acetyl-LDL to isolated rat liver sinusoidal cells revealed the presence of a specific, high-affinity, saturable, membrane-associated receptor with an apparent Kd = 7 micrograms of the ligand at 0 degrees C. Unlabeled acetyl-LDL effectively inhibited 125I-f-Alb binding to the cells. By contrast, the binding of 125I-acetyl-LDL to the cells was affected neither by unlabeled f-Alb nor by the antibody raised against the f-Alb receptor. These results indicate that the scavenger receptors for these two ligands are distinct from each other but similarly sensitive to polyanionic compounds.

Animals↗
PubMed1985

Defective expression of HLA class I antigens: a case of the bare lymphocyte without immunodeficiency.

A case of the bare lymphocyte without apparent immunodeficiency was observed in a 33-year-old woman who had no history of severe infections but suffered from sino-bronchial disease. No HLA-A and -B antigens (class I antigens) were detected at the cell surface of lymphocytes, granulocytes, and platelets, but they were expressed, although at a reduced level, on the cultured B lymphoid cell line. T lymphocytes were normal in number and in the relative proportion of T4/T8 and responded to mitogens but not to PPD and candida. HLA-DR antigens (class II antigens) were present on B lymphocytes and showed intermediate MLR-stimulatory capacity, which made it possible to deduce the patient's HLA genotype. She was found to be homozygous at consanguinity for HLA-A, -B, and -DR antigens. The numbers of B lymphocytes, immunoglobulins, and complements were all in the normal range; there was, however, a low level of IgM. Two-dimensional gel analysis of class I antigens revealed the presence of normally expressed beta-2 microglobulins (B2M) and an apparently single set of class I heavy chains, allowing us to consider two alternative cellular mechanisms in this defect; the presence of one abnormal class I structural gene and the regulatory mechanism that acted in cis were suggested.

Adult↗
PubMed1985

Prediction of lung cancer spread and functional resectability by 133Xe radiospirometry.

Sixty-six patients with primary lung cancer who underwent thoracotomy were studied to determine the correlations among 133Xe radiospirometry, surgical procedures and histological extension of the lung cancer. Disturbance in the regional perfusion (Q per cent) was more prominent than disturbance of the regional ventilation (V per cent), as the pathological stage and t factor proceeded, while V per cent and Q per cent were disturbed almost equally in relation to the pathological n factor. Lobectomy was impossible in patients with a Q per cent of less than 33 per cent of the total, but low perfusion did not necessarily contraindicate surgery. The predicted postoperative FEV1.0 was calculated according to the equation of (1-b/a x (V per cent or Q per cent)) x (preoperative FEV1.0), where a and b were the number of subsegments in the lung lobes on the involved side and the resected lobe. The predicted and actually measured postoperative FEV1.0 showed significant correlations (less than 0.001) in both equations. We conclude that Q per cent reflects a complex pattern of lung cancer spread more sensitively than does V per cent, and the significance of V per cent and Q per cent in terms of prediction of postoperative EFV1.0 seems to be equivocal.

Aged↗