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Biomedical subjects

M Arai

Publications and source records attributed to M Arai.

At least 631 records · Page 35Linked to original sources
PubMed1984

Effect of inspiratory flow rate on bronchomotor tone in normal and asthmatic subjects.

The effect of the inspiratory flow rate during deep inspiration on the regulation of bronchomotor tone was studied in nine normal and 22 asthmatic subjects. Changes in bronchial tone were assessed by respiratory resistance measured by an oscillation method. In normal subjects with bronchoconstriction induced by methacholine a rapid deep inspiration reduced respiratory resistance more than a slow deep inspiration. Asthmatic subjects with spontaneous airway narrowing showed an increase in respiratory resistance after deep inspiration that was greater after rapid than after slow deep inspiration. On the other hand, in asthmatics with methacholine induced bronchoconstriction, bronchodilatation occurred after deep inspiration and this was also greater after rapid than after slow deep inspiration. Lignocaine inhalation attenuated both bronchoconstriction and bronchodilatation induced by both slow and rapid deep inspiration. These results suggest that the effects of deep inspiration are mediated at least in part via receptors in the airways. It is suggested that in asthmatic patients with spontaneous bronchoconstriction irritant receptor activity will be increased in proportion to the speed of inspiration. After methacholine induced bronchoconstriction stretch receptor activity is likely to behave in a similar fashion, leading to an opposite effect.

Adult↗
PubMed1984

Possible mechanistic roles of anatomical and functional vascular changes in rat urinary bladder carcinogenesis induced by N-butyl-N-(4-hydroxybutyl)nitrosamine.

Anatomical and functional vascular changes during rat urinary bladder carcinogenesis were studied by scanning electron microscopy of vascular casts, transmission electron microscopy of bladder capillaries, and fractional distributions of 51Cr-erythrocytes, 125I-human serum albumin, and 86RbCl which were used to determine vascular volume, permeability, and perfusion. Histopathological changes and focal capillary changes in vascular casts were measured quantitatively by an image analyzer. Male Wistar rats received 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in their drinking water for 8 weeks and were then maintained on tap water without BBN for an additional 32 weeks. Simple hyperplasia was first seen at Week 2. The percentage of the area of hyperplastic epithelium increased to about 95% by Week 8 and then decreased to 4 to 6% at Weeks 20 or 40. Papillary or nodular hyperplasia was first seen at Week 6. The percentage of the area of papillary or nodular hyperplasia increased with time to 31.0% at Week 40. Papillary transitional-cell carcinomas were found from Week 20, increasing with time, and their incidence was 100% after Week 35. Vascular cast diameters of normal-looking capillaries were larger during than after BBN treatment. Type 3 vascular proliferations were found beneath papillary or nodular hyperplasia and cancer. Capillaries beneath simple hyperplasia and type 3 capillaries beneath capillary or nodular hyperplasia and cancers were fenestrated and dilated. Changes in vascular volume were independent of changes in permeability and perfusion. Best-fit curve analyses showed the maximum vascular volume at 8 weeks and minimum at 25 weeks, and the permeability maxima at 4 and 25 weeks with minima at 15 and 32 weeks. While 86Rb values correlated 125I values (r = 0.58), they were unstable in intermediate time periods. Changes of vascular volume were coincident initially with increased areas of dilated capillaries beneath simple hyperplasia and later with areas of type 3 capillary proliferation beneath papillary or nodular hyperplasia and cancer. Changes of vascular permeability were related to inflammation indices throughout the study. Increases in permeability were coincident with fenestrated capillaries beneath simple hyperplasia in early stages, and subsequently with fenestrated type 3 capillaries beneath papillary or nodular hyperplasia and cancer. BBN appears to cause alterations in vascular volume via induction of capillary dilation and also possibly by enhancing the responsiveness of host endothelium to angiogenic stimulation from neoplastic or preneoplastic tissues.

Analysis of Variance↗
PubMed1983

Postzygotic D/D translocation homozygosity associated with recurrent abortions.

A Robertsonian translocation involving homologous D chromosomes was found in two cases with a history of recurrent abortions. In the first case the propositus was a 37-year-old phenotypically normal man who had a balanced t(14q14q) translocation. In the second case, a 27-year-old phenotypically normal woman was found to be a balanced t(15q15q) translocation carrier. The recurrent abortions in both cases were probably owing to this translocation.

Abortion, Habitual↗
PubMed1983

Tumorigenicity of citrinin in male F344 rats.

This study reports on the tumorigenicity of citrinin, a nephrotoxic mycotoxin. Male F344 rats were fed 0.1% citrinin in the diet for up to 80 weeks. The first renal tumor was seen grossly in a rat receiving citrinin which was killed at week 52. Histopathology of the kidneys showed renal adenomas in 35 of 48 (72.9%) rats that survived after 40 weeks. No renal tumors were seen in the control rats.

Adenoma↗
PubMed1983

Long term dose response study of N-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide-induced urinary bladder carcinogenesis.

The effect of dose was evaluated for the bladder carcinogenicity of N-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide (FANFT). The chemical was fed to male weanling F344 rats for 30 weeks followed by 74 weeks of control diet. The incidences of bladder carcinoma were 100, 100, 87, 0, 0 and 0% for doses of 0.2, 0.1, 0.05, 0.01, 0.005 and 0.001%, respectively. There was an inverse relationship between dose and latency period. There was no increased incidence of tumors of other tissues.

Animals↗
PubMed1983

Characterization of anion permeability in AH-66 hepatoma ascites cells.

The sulfate transport in AH-66 hepatoma ascites cells was examined under various controlled conditions using 35SO42- as a tracer. The sulfate efflux rate was dependent on temperature, pH and anion species of the cell suspending medium. The efflux rate became saturated as the concentration of extracellular anions was increased. The efflux of anion was inhibited by some chemical reagents specifically reactive with amino or sulfhydryl groups. The results obtained in this study suggest that sulfate anions were transported by a facilitated transport system(s), and that some membrane protein(s) is involved in the anion transport system(s) of AH-66 cells. Both amino and sulfhydryl groups are thought to play a determinant role at the sulfate transport site in AH-66 cells.

Animals↗
PubMed1983

Serial changes of complement titers in the acute phase of myocardial infarction.

Although some studies suggest the involvement of a complement activation in the development of acute myocardial infarction, there has been little convincing evidence of the change of the complement in patients suffering from myocardial infarction. In 11 patients with acute myocardial infarction the serial changes of the total hemolytic complement titer (CH50), C3, C4, total serum protein and C3 conversion were investigated up to 120 hours after its attack. The level of CH50 and C4 increased consistently in the acute phase of myocardial infarction, but C3 did not show any change and total serum protein declined after 96 hours. Beta 1 A globulin, the split product of C3, could not be detected in the blood stream. These results suggest that the infarcted or ischemic myocardium would activate complements, and C3 might be consumed continuously by the infarcted or ischemic myocardium. Such consumption of complements should stimulate the production of complement and would give rise of an increase in C4 and CH50. It is suggested that activated complement might play a significant role in the development of myocardial infarction.

Adult↗
PubMed1983

Studies on biosynthesis of pentalenolactone. V isolation of deoxypentalenylglucuron.

Deoxypentalenylglucuron was isolated from the culture broths of three different strains, such as Streptomyces omiyaensis, S. albofaciens and S. viridifaciens. The structure of deoxypentalenylglucuron has been determined by 1H and 13C NMR, mass spectroscopy and by chemical correlation to be an oxidation product of pentalenene 1. Deoxypentalenylglucuron (1) has some antitumor activity against Sarcoma 180 in mice.

Animals↗
PubMed1983

Mycoplanecins, novel antimycobacterial antibiotics from Actinoplanes awajinensis subsp. mycoplanecinus subsp. nov. I. Taxonomy of producing organism and fermentation.

Strain No. 41042, an actinomycete isolated from a soil sample, was found to produce 5-azacytidine and new antibiotics, mycoplanecins. Yellowish brown to yellowish orange color of colonies on agar media, formation of globose to subglobose sporangia bearing motile spores and presence of meso- and hydroxy-diaminopimelic acid and glycine in the cell wall ascribed this strain to genus Actinoplanes. From its morphological, cultural and physiological characteristics, this strain was determined to be a new subspecies of Actinoplanes awajinensis and designated as A. awajinensis subsp. mycoplanecinus subsp. nov. Production of mycoplanecins was carried out by conventional submerged culture: the highest antibiotic titer obtained was 145 micrograms/ml.

Actinomycetales↗
PubMed1983

Mycoplanecins, novel antimycobacterial antibiotics from Actinoplanes awajinensis subsp. mycoplanecinus subsp. nov. II. Isolation, physico-chemical characterization and biological activities of mycoplanecin A.

New antibiotics, mycoplanecins, were found in the culture broth of an actinomycete identified as Actinoplanes awajinensis subsp. mycoplanecinus subsp. nov. Mycoplanecin complex was extracted with organic solvents both from the culture filtrate and mycelium and purified by column chromatography on silica gel and Florisil. Mycoplanecin A, a major component, was separated by high performance liquid chromatography on Prep PAK-500/C18 column. The physico-chemical characterization revealed that mycoplanecin A was a new cyclic peptide antibiotic. Mycoplanecins exhibited strong activities primarily against mycobacteria and related microorganisms.

Actinomycetales↗
PubMed1983

Mycoplanecins, novel antimycobacterial antibiotics from Actinoplanes awajinensis subsp. mycoplanecinus subsp. nov. III. Structural determination of mycoplanecin A.

The structure of mycoplanecin A was determined by the analysis of chemical degradation products and by mass and 1H and 13C NMR spectrometries. Mycoplanecin A is a new cyclic peptide antibiotic composed of mol each of alpha-ketobutyric acid, glycine, L-leucine, L-proline, L-2-amino-5-methylhexanoic acid, N-methyl-D-leucine, N-methyl-L-threonine, methyl-L-proline and ethyl-L-proline and two mol of N-methyl-L-valine. Among these components, ethyl-L-proline is reported for the first time as a component of natural products. A newly developed mass analysis has been introduced for the differentiation of alpha-amino acid and its N-methyl derivative.

Actinomycetales↗