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Biomedical subjects

N Harada

Publications and source records attributed to N Harada.

At least 631 records · Page 35Linked to original sources
PubMed1982

Assay of alpha-cysteine proteinase inhibitor in serum or plasma.

A new proteinase inhibitor has recently been found in human serum or plasma which specifically inhibits cysteine proteinases such as ficin, papain, bromelain and cathepsin B. However, serum contains alpha 2-macroglobulin which also inhibits these cysteine proteinases and, consequently, interferes with the assay of the new alpha-cysteine proteinase inhibitor. Therefore, assay of the inhibitor in serum has not been established previously. In the present method, the alpha 2-macroglobulin is inactivated by preincubating the serum in methylamine solution at 55 degrees C, while the alpha-cysteine proteinase inhibitor retains its activity. The inhibitory power against cysteine proteinases is found to be due mainly to this protein in human serum. This inhibitor is also found in mammals such as cows, pigs and rats. Vitamin E deficient rats show a very high inhibitor level. Therefore, the present method will enable us to investigate the relation between diseases and the activity of the alpha-cysteine proteinase inhibitor. Also, this method is simple and inexpensive. The necessary amount of serum is only 10 microliter.

Animals↗
PubMed1982

[On vibration hazards of chipping-hammer operators in an iron foundry. Part 2. Results of the hygienic control].

We previously reported that the working and health conditions of vibrating tool operators in an iron foundry were investigated in 1975 and vibration hazards were observed to occur frequently in workers operating chipping-hammers powered by compressed air. After that, we instituted medical treatment for the afflicted workers and improvement of working conditions in the foundry, and have performed annual medical examinations for four years. In this paper, the course of hygienic control and the change in the medical findings of twenty-four chipping-hammer operators are reported. 1. The following measures were taken to improve the working conditions of chipping-hammer operators and therapy for patients (Table 1): (1) The operating time of vibrating tools, including chipping-hammer, was limited to two hours per day. The casting process was improved to diminish the flashes that are the objects of chipping-hammer operation. For the purpose of reducing the vibration transmitted to the operator, a servo-arm that has a servomechanism for the chipping-hammer was developed and introduced. (2) Infrared lamps in the foundry and air curtains at the doorway were installed for keeping the chipping-hammer operating area warm. A warm room was set up in the foundry for providing warmth during rest periods and protective clothing against the cold was provided. (3) Workers who displayed health disturbances by medical examinations were treated during the cold season from November to April by periodic visits to the clinic or extended hospitalization, or transferred to job without vibration exposure, according to their stage of disease. Preventive treatment with vasodilator and bubble bath was performed in winter for the chipping-hammer operators. 2. In order to estimate the effect of these countermeasures, annual medical examinations were conducted in March 1975, March 1976, April 1977 and March 1978. Such subjective symptoms as Raynaud's phenomenon, finger numbness, finger listlessness, heavy-headedness, forgetfulness, irritability and hearing disorder showed a tendency for improvement, but other complaints did not (Tables 2-4). The improvement of Raynaud's phenomenon is considered to be due not merely to the countermeasures but also to reducing the chance of provocation and therefore the countermeasures should not be overestimated as a factor of recovery of vibration hazards. Of the functional tests, a tendency for improvement was recognized in sensory functions and peripheral circulatory functions, but not in motor functions (Tables 5, 6). However, the course of recovery was not fast and some advanced cases, especially those using chipping-hammers for more than ten years, showed less improvement after hospital treatment (Table 7, Fig. 1). This indicates the importance of hygienic control which enables vibration hazards patients to have early diagnosis and treatment. Furthermore, in order to eradicate the vibration hazards in the cast metal industry, a drastic reform of the finishing process is considered to be necessary.

Adult↗
PubMed1982

Growth factor from tumor cells.

Suitable conditions for assay of the growth factor from Yoshida sarcoma and AH-130 tumor cells were investigated using three different cell lines: baby hamster kidney cells, human embryonic lung cells and Swiss Albino mouse 3T3 embryo fibroblast cells. The results indicated that the 3T3 cell line was more sensitive to the growth stimulating activity than the other two lines. A fraction of Yoshida sarcoma tumor cells containing the growth factor showed less growth stimulating activity than a fraction of AH-130 tumor cells prepared by the same method. Using the 3T3 cell line for assay of activity, the growth factor was partially purified from AH-130 tumor cells by ammonium sulfate fractionation, DEAE-cellulose column chromatography and gel filtration on a Sephacryl S-300 column. It appeared to be thermolabile, and its molecular weight was estimated as about 80,000 by gel filtration on Sephacryl S-300. These findings suggest that it is a high-molecular-weight substance.

Animals↗
PubMed1981

A study of various function tests on the upper extremities for vibration syndrome.

For early diagnosis of vibration syndrome, it is necessary to detect the insidious functional disorders which appear without organic changes in it's early stage. In Japan, peripheral circulation and sensory tests, including tests after cold water immersion, and functional capacity motor tests are performed widely on the upper extremities. We have examined workers exposed to three kinds of vibration, and control workers, using these function tests, and analyzed the data with the use of principal component analysis. As a result, these function tests were considered to be of diagnostic significance as a screening test for vibration syndrome. It is also suspected that peripheral circulation disturbance, sensory disturbance and motor disturbance found in vibration syndrome advance independently of each other. Disparities in the findings of vibration syndrome were recognized and were attributed to differences of work conditions.

Adult↗
PubMed1981

Selective induction of two different molecular species of cytochrome P-450 by phenobarbital and 3-methylcholanthrene.

Two forms of cytochrome P-450, P-450PB and P-450MC, were purified to homogeneity from the liver microsomes of phenobarbital (PB)-treated and 3-methylcholanthrene (MC)-treated rats, respectively. Rabbit antibodies against P-450PB and P-450MC were prepared and the monospecificity of each antibody preparation was confirmed by various lines of evidence. By the use of these antibodies, the contents of P-450PB and P-450MC in microsomes could be determined separately by quantitative immunoprecipitation. P-450PB and P-450MC each amounted to about 10% of total cytochrome P-450 in the microsomes of normal rats. However, each of them was selectively and substantially increased by the appropriate inducer, and became a predominant component of cytochrome P-450 in the microsomes of drug-treated animals. The increase of each specific molecular species of cytochrome P-450 was about 10- and 20-fold within 48 h, whereas the increase of total cytochrome P-450 was only about 2- to 3-fold even after maximal induction by the drugs. The drug oxidation activities of P-450PB and P-450MC were also significantly altered by the drug treatments. The administration of MC to PB-treated rats induced a drastic decrease in the P-450PB-dependent oxidations of benzo(a)pyrene and 7-ethoxycoumarin, while the corresponding activities of P-450MC increased sharply, and these changes were much more rapid than the change of the amount of each form of cytochrome P-450. However, the oxidation of benzphetamine was almost exclusively P-450PB-dependent even after extensive induction by MC. These observations suggest that the specific activities of p-450PB and P-450MC in the oxidations of various drugs are quite differently affected by the induced states of animals.

Animals↗
PubMed1981

Intestinal absorption of bile alcohols.

The absorption of bile alcohols by rat small intestine was studied using in vivo and in vitro preparations. In bile duct cannulated rats, intraduodenal administered bile alcohols were certainly absorbed and excreted in the bile, although the absorption was not so efficient as for bile acids. The absorption during a 24 h period for free bile alcohol, bile alcohol 3-sulfate, and bile alcohol 3-glucuronide was 60%, 31%, and 30% of the dose, respectively, compared with 98% for taurocholate. In situ recirculation experiments demonstrated the linear relationship between perfusate concentration and intestinal absorption for unconjugated and 3-sulfated bile alcohols. Everted gut sacs of rat ileum actively transported a bile alcohol possessing a sulfuric acid ester group on the side chain. However, free bile alcohol, bile alcohol 3-sulfate, and bile alcohol 3-glucuronide were not transported. These results indicate that bile alcohols having no negative charge on the side chain are absorbed by passive diffusion and not by active transport.

Animals↗
PubMed1980

Relationship between structure, positive inotropic potency and lethal dose of grayanotoxins in guinea pig.

Relationship between chemical structure, positive inotropic potency and lethal dose of grayanotoxins and the related compounds was studied using guinea pigs. The positive inotropic effect (PIE) was examined in their papillary muscle isolated from the heart. The potency of these compounds was expressed by pD2 values, and was determined by depicting the concentration-PIE curve for each compound. The study has clarified the contribution of functional groups in the molecule; the presence of 3 beta-hydroxyl, 6 beta-hydroxyl and 10 beta-methyl groups attached to the grayanane skeleton is established to be essential for the development of PIE. The inotropic potency of compounds carrying these essential groups is increased by a 10 alpha-hydroxyl group and the acylation of the 14 beta-hydroxyl group. LD50 value of 10 compounds with a high cardiotonic potency (pD2 greater than 4) was determined by up and down method using male guinea pigs. The relation of LD50 to pD2 bore a significant correlation (r = 0.68, p less than 0.05). The most cardiotropic and toxic compound found in this study was asebotoxin III.

Animals↗
PubMed1980

Participation of cytochrome P-450 in the reduction of nitro compounds by rat liver microsomes.

1. The subcellular distribution of nitrobenzene reduction activity in rat liver cells indicated the existence of two different enzyme systems, one localized in microsomes and the other localized in cytosol. The activity in the cytosol was mainly attributable to xanthine oxidase, judging from its substrate specificity and the inhibition by allopurinol. 2. The participation of the microsomal electron transport system in nitrobenzene reduction was examined by using antibodies against four components of the system, NADPH-cytochrome c reductase (fpT), NADH-cytochrome b5 reductase (fpD), cytochrome b5, and cytochrome P-450. Both NADH- and NADPH-dependent nitrobenzene reduction activities were strongly inhibited by anti-fpT IG and also by anti-P450 IG, but not inhibited by anti-fpD IG or anti-b5 IG. The reduction of nitrosobenzene and phenylhydroxylamine, which are supposed to be the intermediates of nitrobenzene reduction, was also examined, and it was found that NADH- and NADPH-dependent reduction of both compounds were strongly inhibited by anti-fpT IG and anti-P450 IG, but not by anti-fpD IG or anti-b5 IG. 3. Reconstruction experiments using purified NADPH-cytochrome P-450 reductase and cytochrome P-450 were also carried out and it was confirmed that the reduction of nitrobenzene, nitrosobenzene, and phenylhydroxylamine to aniline could be effected by these two components. 4. Nitrobenzene reduction by microsomes exhibited a short initial time lag and was activated by the addition of purified NADPH-cytochrome c reductase, whereas nitrosobenzene and phenylhydroxylamine reductions did not show any initial time lag and were not activated by the reductase. These observations suggest that the reduction of nitrobenzene to an intermediate, possibly nitrosobenzene or phenylhydroxylamine, limits the rate of aniline formation, and such an initial step of nitrobenzene reduction can be catalyzed by NADPH-cytochrome c reductase alone. Cytochrome P-450 is essential at least in the final step of nitrobenzene reduction to aniline. This conclusion was further confirmed by determination of these intermediates in nitrobenzene reduction.

Animals↗
PubMed1980

DNA synthesis in tumor-bearing rats: purification of liver thymidine kinase stimulating factor from Yoshida sarcoma.

Yoshida sarcoma cells contain a factor that stimulates thymidine kinase activity in the liver of mice in vivo; intraperitoneal injection of an extract from Yoshida sarcoma into normal mice stimulated their liver thymidine kinase activity 2- to 3-fold, whereas injection of a crude extract of normal rat liver did not stimulate the activity at all. A factor that stimulates the de novo synthesis of thymidine kinase in the liver was partially purified from Yoshida sarcoma by ammonium sulfate fractionation, DEAE-cellulose column chromatography and gel filtration. It appeared to be thermolabile and sensitive to trypsin treatment. These results suggested that it was a high-molecular weight protein. Intraperitoneal injection of this factor into 67% hepatectomized rats stimulated thymidine kinase activity 2- to 3-fold. Increase of liver thymidine kinase activity after injection of the factor into mice was blocked by simultaneous injection of actinomycin-D. These results suggest that this factor stimulates de novo synthesis of thymidine kinase in the liver.

Animals↗