Biomedical subjects

K Hayama

Publications and source records attributed to K Hayama.

16 recordsLinked to original sources

PubMed1995

[Measurement of airborne fumes in welding factories].

Concentrations and size distributions of airborne welding fumes in work environments were measured. Samples were collected from 20 workplaces in 13 companies. In all workplaces, the stationary samplings including A-sampling and B-sampling and the personal sampling were carried out simultaneously. The fume concentration in the stationary sampling was measured with a digital dust monitor. A low volume air sampler and an Anderson cascade impactor was also used to determine the conversion factor of the values obtained by the digital dust monitor and the size distributions of the fumes. The personal exposure levels were measured with a TR sampler and a personal cascade impactor. The concentrations by the personal sampling (average: 11.3mg/m3) were much higher than those by the A-sampling (average: 0.4mg/m3 and range: 0.15-0.64mg/m3) but lower than those by the B-sampling (average: 46.8mg/m3, range: 0.66-152.8mg/m3). The mass median aerodynamic diameter (MMAD) of the stationary and the personal samplings were 2.41 microns and 0.80 microns, respectively. Fumes were observed under a scanning electron microscope. Most of the fume particles were sphere in shape but smaller fumes were aggregated and formed larger secondary particles.

Dust↗

PubMed1995

Clinical significance of antiphospholipid antibodies in fulminant hepatic failure.

We examined the incidence of antiphospholipid antibodies (APA) in patients with fulminant hepatic failure (FHF) and various liver diseases using the enzyme-linked immunosorbent assay (ELISA), and assessed possible correlations with the pathophysiology of these diseases. The APA assay employed cardiolipin (CL), phosphatidylserine (PS), and phosphatidylinositol (PI) as antigens. Anti-CL IgA antibody was detected in 13/14 (92.9%) patients with FHF. The incidence of anti-CL-IgG, anti-CL-IgM, anti-PS-IgG, and anti-PI-IgG was 14.3%, 35.7%, 64.3%, and 71.4%, respectively. Despite the high incidence of APA in FHF, these antibodies were not detected in most patients with acute or chronic hepatitis. There was a negative correlation between anti-CL-IgA and the platelet count, and a negative correlation between anti-PI-IgG and the amount of residual liver parenchyma. Our results suggest that APA develop secondarily to hepatocyte or sinusoidal cell damage and may aggravate both thrombocytopenia and liver failure.

Adult↗

PubMed1994

The anticardiolipin antibody in elderly stroke patients: its effects on stroke types, recurrence, and the coagulation-fibrinolysis system.

Anticardiolipin antibody (aCL) is known as a risk marker for stroke, particularly in subjects younger than 50 years of age. We studied the effects of aCL on stroke types, recurrences, and the coagulation-fibrinolysis system in 257 elderly patients (63.2 +/- 11.4 years). Follow-up was performed for 3.1 years on 184 patients, for whom the rate of symptomatic and asymptomatic reinfarcts on CT was studied. aCL was positive in 30 (12%) of the patients. The incidence of atherosclerotic changes in the cerebral arteries was not significantly different between aCL-positive and aCL-negative patients. The aCL-positive patients had a greater rate of individuals not having any of the known risk factors (p < 0.05), a greater incidence of cortical infarctions (p < 0.05), more frequent symptomatic recurrences (p < 0.05). They had significantly greater changes in molecular markers for the coagulation-fibrinolysis system in the acute phase (p < 0.05), but not in the chronic phase.

Aged↗

PubMed1993

G protein beta gamma-subunits inhibit purified adenylate cyclase independent of the activation by Ca2+ and calmodulin.

Adenylate cyclase purified by affinity chromatography was activated about 2.5-fold in a Ca(2+)- and calmodulin-dependent fashion. G protein beta gamma-subunits, an inhibitor in the receptor-mediated inhibition of adenylate cyclase, inhibited the purified cyclase by more than 80%. The extent of beta gamma-induced inhibition was not affected by the activation with Ca2+ and calmodulin. Moreover, the prior addition of the beta gamma-subunits to the cyclase did not prevent the subsequent activation of the enzyme by Ca2+ and calmodulin. We conclude that the beta gamma-subunits inhibit adenylate cyclase activity in a calmodulin-independent mode.

Adenylyl Cyclase Inhibitors↗

PubMed1989

High-incidence of C9 deficiency throughout Japan: there are no significant differences in incidence among eight areas of Japan.

From 92,686 sera sent from hospitals throughout Japan to the Special Reference Laboratories for CH50 assay, we were able to classify 80 patients as C9-deficient using a sensitive screening test, as well as hemolytic and immunochemical C9 assays. The incidence of C9 deficiency was determined to be 0.086%, and there were no distinct differences among the eight areas of Japan tested. Serum CH50 levels of these C9-deficient patients varied widely (9.4-63.8 U/ml), and exhibited a higher value (average: 34.1 U/ml) than that of healthy C9-deficient individuals, probably due to elevated C3, C4, and C5 levels. These patients suffered from a variety of autoimmune, renal, and infectious diseases, which, however, are thought to be only incidentally associated with C9 deficiency.

Complement C9↗

PubMed1989

[Study on renal osteodystrophy using 2-compartment model analysis of bone scintigraphy. 1. Clinical significance of K Index].

The dynamic analyses of bone scintigraphy were performed in 30 cases of hemodialysed patients. The regression analyses between biochemical data or duration and K indexes obtained from the 2-compartment model analysis in the maxillofacial region were carried out. The obtained results were as follows. 1) The duration and K indexes were significantly correlated with 1 or 2% of significance level in the parietal bone and the zygomatic bone. 2) Serum Ca and K indexes were highly correlated in every settled ROI. The correlation coefficients were distributed from 0.58 to 0.79. In the cranial bone the correlation were more higher than in maxilla and mandibular bone. 3) Serum ALP and K indexes have more higher significant level of correlation than the results of Ca. The correlation coefficients were distributed from 0.48 to 0.83. The level of significance were changed by location. The highest correlation coefficient was 0.83 in the parietal bone. 4) Serum c-PTH and K indexes have significant correlation in every settled ROI with the correlation coefficient from 0.59 to 0.69. The significance level were nearly equal in every location. 5) In the case of subtotal parathyroidoectomy the K indexes which were abnormally high in preoperation showed the tendancy to decrease toward normal range in postoperation. These results indicated that K indexes reflected the bone change caused by renal osteodystrophy. And the K indexes considered to be usefull to estimate the bone improvement.

Bone and Bones↗

PubMed1989

[Fundamental examination and the reference values of anticardiolipin antibodies].

We studied sera from 146 healthy individuals in a fundamental examination to obtain reference values for anticardiolipin antibodies by the enzyme-linked immunosorbent assay (ELISA). The good results were obtained in the evaluation of concentrations of pretreatment substances, cardiolipin antigen and serum samples, as well as in reproducibility and stability on the storage of the samples. However, there was interference by triglycerides, hemoglobin and birilubin. The O.D. values and positive values of IgG, IgA and IgM in healthy individuals were 0.105, 0.111, 0.173 and 4.1%, 2.7%, 2.7% respectively. Furthermore, the incidences of anticardiolipin antibodies in systemic lupus erythematosus, mixed connective tissue disease, progressive systemic sclerosis, Sjogren's syndrome, polymyositis/dermatomyositis, rheumatoid arthritis, unclassified connective tissue disease, polyartertis nodosa and idiopathic thrombocytopenic purpura were 48.0%, 40.0%, 50.0%, 21.4%, 26.3%, 29.4%, 40.0% and 25.0% respectively. Especially, the incidence of IgG antibody against cardiolipin was high. Detection of phospholipid cardiolipin antibodies using ELISA was considered to be a useful for clinical diagnosis and monitoring of patients with systemic lupus erythematosus and associated autoimmune disorders.

Autoimmune Diseases↗

PubMed1988