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C Hayashi

Publications and source records attributed to C Hayashi.

At least 55 records · Page 3Linked to original sources
PubMed1992

[What is the role of statistics in medical science?--a critical essay].

In the present paper, the fundamental problems of statistics used in medical science are discussed, based on radical criticism and thorough examination of statistical ideas and methods which are popularly used in the medical field of today. The formal applications of statistical test and estimation theories in mathematical statistics and further belief in double-blind experimental design are frequently found in medical science, where the meaning of population is not made clear and the true characteristics of "statistical test and estimation" and of "double-blind experimental design" are either not understood or are misunderstood. These facts bring many evil influences on medical ideas leading to medical trials. Radical criticism and thorough examination are necessary for the return of medical research to the right path. New statistical ideas and methods must be developed on the basis of the considerations mentioned above. The use of statistics must be made with a modest attitude and exploratory or detective ideas must be adopted, in so far as medical trials are administered, with human mind, to individuals who are intricate and multifarions in reaction. Medical trials and statistics are to be unified in order that desirable results may emerge in human world, enhancing the validity of their contents each other. Here, for example, the exploratory method of multidimensional data analysis and the idea of optimal control with QOL of individuals in medical trials are explained.

Humans↗
PubMed1990

Production of endothelin in human cancer cell lines.

Endothelin (ET)-1 is a vasoconstrictor peptide derived from endothelial cells and now known to be a local regulator of vascular tonus. Recent studies, however, have revealed that ET-1 functions also as growth factor in various cells. By using a specific ET-1 radioimmunoassay, immunoreactive (IR) ET-1, ranging from 4.2 to 150 pM (minimum detectable amount, 4.0 pM), was detected in 13 of 42 human cancer cell lines. The frequencies of IR-ET-1 production and its concentrations were high in mammary, pancreatic, and colon carcinoma cell lines. IR-ET-1 produced by cancer cells possessed the same molecular size as synthetic ET-1 and also had ET-1-like biological activity. Moreover, Northern blot analysis revealed bands corresponding to ET-1 mRNA in cancer cell lines, indicating that IR-ET-1 produced by cancer cells is a product of the ET-1 gene. Since ET-1 in the spent media is present in a sufficient amount to stimulate cellular growth, we sought ET-1 receptors in four pancreatic carcinoma cell lines and human skin fibroblasts. No ET-1 receptors were detected in the pancreatic carcinoma cell lines. However, human skin fibroblasts possessed a large number of ET-1 receptors. This finding raises the possibility that ET-1 produced by cancer cells plays a modulatory role in the growth of stromal cells surrounding cancer cells.

Cell Line↗
PubMed1990

Comparative assessment of dual-photon absorptiometry and dual-energy radiography.

Dual-energy bone densitometry can be performed with two types of scanners. The traditional dual-photon absorptiometry (DPA) machines use an isotope source, whereas the newly introduced dual-energy radiography (DER) devices use an incorporated x-ray tube. The authors evaluated the performance of DPA and DER devices at their institution. The short-term precision error in vivo was 1.2% for femoral neck measurements with DER. Long-term precision error in vitro was reduced from 1.30% (DPA) to 0.44% (DER). The scanning time for both spine and hip measurements was reduced from 20-40 minutes to 6-7 minutes. Intraosseous fat sensitivity remained the same, at a level of 12 mg/cm2 apparent decrease of bone mineral density (BMD) per 10% fat by volume change, and for both devices there was no shift in BMD when phantom thickness was increased by 1.5 inches. The correlation of DPA and DER was high: r = .98 for the spine and r = .95 for the femoral neck. Correlation of DPA versus quantitative computed tomography (CT) (r = .83) and DER versus quantitative CT (r = .85) was good. The advent of DER represents a significant advance for the field of bone densitometry.

Absorptiometry, Photon↗
PubMed1989

In vitro and in vivo antagonists against parathyroid hormone-related protein.

Four analogues of parathyroid hormone-related protein (PTHrP), PTHrP(7-34)NH2, (10-34)NH2, (15-34)NH2 and (20-34)NH2, were synthesized and their antagonistic activity against PTHrP(1-34) was examined in vitro and in vivo. In vitro studies revealed that all four analogues antagonized PTHrP-stimulated cyclic AMP production in rat osteosarcoma cells (ROS 17/2.8), and that PTHrP(7-34)NH2 and PTHrP(10-34)NH2 had potent antagonistic activity. In vivo experiments in nude mice also revealed that PTHrP(7-34)NH2 completely inhibited hypercalcemia induced by PTHrP(1-34), indicating that these analogues antagonize the effects of PTHrP(1-34) in vitro and in vivo.

Adenylyl Cyclases↗
PubMed1989

[Chronic subdural hematoma occurring in patients with senile dementia: report of 4 cases].

Four cases are presented of male patients over 63 years of age. Preceding head injuries relating to chronic subdural hematoma (CSH) were noted in 2 patients. Suspected clinical signs of CSH were disturbance of consciousness and mono- or hemiparesis. Surgery, a burr-hole technique for external drainage, was performed in 2 patients, and nonsurgical treatment by intravenous administration of glycerol was carried out in the remaining 2 patients. After the treatment, 3 patients returned to the previous demented state, and one who had been treated nonsurgically died of pneumonia. Disappearance or marked reduction of the hematoma was demonstrated by follow-up CT scans in all patients. The signs induced by CSH in a patient with senile dementia may be misunderstood as an aggravation of senile dementia. Nonsurgical treatment with osmotic perfusions for CSH may be considered as a treatment of first choice in a patient with advanced senile dementia, unless he shows advanced mass effect of the hematoma on CT.

Aged↗
PubMed1988

Protein C in human plasma determined by homogeneous enzyme immunoassay with use of a centrifugal analyzer.

We describe the simple and rapid enzyme immunoassay of protein C in human plasma with use of a Cobas Fara centrifugal analyzer. The antibody, labeled with horseradish peroxidase, is reacted with antigen (protein C) for 15 min. The peroxidase activity of the resulting antigen-antibody conjugate is measured at 500 nm for 5 min in the presence of excess H2O2, phenol, and 4-aminoantipyrine, as compared with that of free conjugates. Results are calculated from a stored standard curve and expressed as a percentage of the value determined for a pooled specimen of normal adult plasma. The standard curve is linear from 0% to 200%. The CV is generally less than 4% for different concentrations of protein C. In liver cirrhosis, hepatocellular carcinoma, therapy with warfarin, thrombosis, and disseminated intravascular coagulation, protein C concentrations are about 40-70% of normal. Results obtained with the present homogeneous enzyme immunoassay correlated well with those by enzyme-labeled immunosorbent assay (r = 0.97).

Adult↗
PubMed1987

[Susceptibility of clinical isolates to aztreonam].

Aztreonam (AZT), which has a newly developed and synthetic structure belonging to the group of monobactams, possesses excellent antibacterial activity against a broad range of Gram-negative bacteria (including the beta-lactamase producing strains). Antibacterial activities of AZT were examined and compared with those of 5 antibiotics (cefoperazone (CPZ), latamoxef (LMOX), cefotaxime (CTX), cefmetazole (CMZ) and cefsulodin (CFS) against 296 strains of clinical isolates. The evaluation of antibacterial activities was determined with the inhibition zone diameter obtained by the single disc method. The results can be summarized by three categories as follows: 1. Susceptibility of clinical isolates to AZT and other antibiotics AZT and other 3rd-generation antibiotics (CPZ, LMOX, CTX) showed excellent antibacterial activities against most strains. Especially AZT was more active against Enterobacter cloacae and Serratia marcescens than reference drugs. Against Pseudomonas aeruginosa, the activity of AZT was similar to that of CFS. AZT showed as excellent activity against P. aeruginosa as CFS. 2. Susceptibility of strains isolated from different clinical materials and different clinics AZT showed the highest antibacterial activity against the clinical isolates from sputum, pharynx, urine, pus, bile, puncture fluid, blood and others. AZT exhibited the most potent activity against isolates in the 7 clinics we tested. 3. Susceptibility of strains isolated from inpatients and outpatients AZT demonstrated the highest antibacterial activity (the rate of susceptibility: 87.0%) against strains obtained from inpatients (except for P. aeruginosa). The activity of AZT (81.4%) against P. aeruginosa was as active as that of CFS (81.4%), and it was the highest in all drugs. Antibacterial activity of these antibiotics against bacteria was rated as follows: AZT greater than LMOX greater than CPZ greater than CTX greater than CMZ AZT showed the highest antibacterial activity (100%) against strains isolated in all the materials and at all the clinics tested of outpatients. Antibacterial activity of these antibiotics against isolates from outpatients was rated as follows: AZT greater than CPZ greater than LMOX greater than CTX greater than CMZ.

Aztreonam↗