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Biomedical subjects

A Nagata

Publications and source records attributed to A Nagata.

At least 145 records · Page 8Linked to original sources
PubMed1986

A possible mechanism of induction and translocation into blood stream of rat alkaline phosphatase activity by bile duct ligation.

We investigated the effects of bile duct ligation on alkaline phosphatase (ALP) activities in liver, calvarium, duodenum, and ileum in rats and its possible mechanism of action. ALP isozyme activities in the ligated rats were significantly elevated in the liver and duodenum, while those in the ileum and calvarium were markedly decreased. The ALP isozyme activity elevated by the ligation was obviously suppressed by prior administration of indomethacin, an inhibitor of prostaglandin synthesis. Moreover, phorbol ester also elevated the ALP activity as well as the phosphatase level in the ligated rat. However, other drugs, such as an inhibitor of protein kinase C and calmodulin, showed different effects: calmodulin stimulated an 11.0-, 1.3-, or 1.5-fold increase in ALP activity in the ileum, duodenum, or calvarium, respectively; whereas the hepatic enzyme activity was not affected. The induction by calmodulin was markedly different from that by the ligation. Moreover, imipramine, an inhibitor of protein kinase C, had little effect. These results suggest that prostaglandin is a possible ALP inducer in ligated rats, probably working by elevating the cAMP level. On the other hand, the ligation induced simultaneously de novo synthesis of the membranous and soluble ALP isozymes; and the release rate of the soluble enzyme was greater than that of the membranous isozymes, indicating that the soluble enzyme might be a main source of the induced serum ALP. Lectin affinity chromatography indicated that the soluble enzyme or induced serum enzyme may contain more fucose than that of the membranous one, suggesting that the sugar moiety in the ALP molecule may relate to the clearance of ALP from or its release into the circulation.

Alkaline Phosphatase↗
PubMed1986

Ontogenic and phylogenic studies of intestinal, hepatic, and placental alkaline phosphatases. Evidence that intestinal alkaline phosphatase is a late evolutionary development.

We have studied the intrauterine development of guinea pig and rat organ phosphatases using biochemical, immunologic, and histologic techniques. In all organs tested the features of the adult phosphatase activity were achieved during the second or third gestational phases. In the rat, the tissue-unspecific phosphatase activity was found by immunoprecipitation with antiserum to rat liver phosphatase in all gestational phases in liver and placenta. The high liver activity in the first phase of gestation corresponded to hematopoietic cells. Hepatocyte phosphatase did not appear until the second gestational phase. The tissue-unspecific phosphatase activity was found in the first and second gestational phase in surface intestinal epithelial cells, even after crypt formation occurred. Once phosphatase appeared in enterocytes on villi, only the intestinal-type enzyme was detected. Alkaline phosphatase was measured in the liver and intestine from animals in various phyla. In fish and reptiles, the intestinal activity had the enzymatic characteristics of the tissue-unspecific enzyme. The appearance of intestinal alkaline phosphatase with unique properties and high specific activity is a characteristic of mammals.

Alkaline Phosphatase↗
PubMed1986

Intramuscular and surface electromyogram changes during muscle fatigue.

Twelve male subjects were tested to determine the effects of motor unit (MU) recruitment and firing frequency on the surface electromyogram (EMG) frequency power spectra during sustained maximal voluntary contraction (MVC) and 50% MVC of the biceps brachii muscle. Both the intramuscular MU spikes and surface EMG were recorded simultaneously and analyzed by means of a computer-aided intramuscular spike amplitude-frequency histogram and frequency power spectral analysis, respectively. Results indicated that both mean power frequency (MPF) and amplitude (rmsEMG) of the surface EMG fell significantly (P less than 0.001) together with a progressive reduction in MU spike amplitude and firing frequency during sustained MVC. During 50% MVC there was a significant decline in MPF (P less than 0.001), but this decline was accompanied by a significant increase in rmsEMG (P less than 0.001) and a progressive MU recruitment as evidenced by an increased number of MUs with relatively large spike amplitude. Our data suggest that the surface EMG amplitude could better represent the underlying MU activity during muscle fatigue and the frequency powers spectral shift may or may not reflect changes in MU recruitment and rate-coding patterns.

Action Potentials↗
PubMed1986

Study of chronic alcoholic pancreatitis by means of serial pancreozymin-secretin tests.

Fourteen patients with suspected chronic alcoholic pancreatitis (CAP) and 21 patients who had been shown to have the disease were followed up by the pancreozymin-secretin test in order to clarify the serial changes in exocrine pancreatic function in alcoholic pancreatitis. The initial and final test data for secretory volume, maximal bicarbonate concentration, bicarbonate output (BO), and amylase output (AmO) of exocrine secretion were compared in these two groups. Patients with suspected CAP showed a significant serial decrease only in AmO; definite CAP developed in 3 of them during the follow-up period. In definite CAP, a significantly progressive decrease in BO as well as AMO was observed. It is suggested that in the earlier stage of CAP, AMO is initially affected, whereas decreased secretion of both bicarbonate and enzyme becomes apparent in the later stage.

Adult↗
PubMed1986

Anterior dislocation of the shoulder. Experience with a modified clavicular harness.

There is a high incidence of recurrence after traumatic dislocation of the shoulder. In this study of 417 patients, we found that initial dislocation below the age of 30, dislocation with capsular detachment, dislocation without tuberosity fracture and a short period of fixation after reduction were predisposing factors. We have designed a modified clavicular harness and have used it in the treatment of 41 such high risk patients. We found no recurrences during an observation period of one year.

Adolescent↗
PubMed1985

Exocrine pancreatic function in asymptomatic chronic alcoholics without structural pancreatic disease.

In order to elucidate the functional states of the pancreas in the asymptomatic latent stage of chronic alcoholic pancreatitis, 45 chronic alcoholics with no obvious pancreatic structural abnormalities judged by endoscopic pancreatography were studied by pancreozymin-secretin test. We found three patterns of exocrine pancreatic function in alcoholics with or without cirrhosis: normal secretion (40%), hyposecretion (29%) and hypersecretion (31%). In the hyposecretory group, the amylase output proved to be impaired more frequently. In the hypersecretory group increases were observed in one or more of the following parameters, volume, bicarbonate output and amylase output. However, increase in volume was a fundamental condition in this hypersecretion. This study confirmed that exocrine pancreatic hyposecretion and hypersecretion were almost equally frequent in asymptomatic chronic alcoholics with no obvious pancreatographic abnormalities. These results suggest that ongoing exocrine pancreatic dysfunctions exist in the subclinical stage of chronic alcoholic pancreatitis.

Adult↗
PubMed1985

DNA content of hepatocytes in various stages of liver cirrhosis.

In order to search for some parameters that would make it possible to predict a potentially high risk of evolution from liver cirrhosis to hepatocellular carcinoma (HCC), the DNA content of hepatocytes in patients with liver cirrhosis with or without development to HCC was investigated by means of microspectrophotometry in Feulgen-stained specimens. In patients without development of HCC in more than 5 years of follow-up, 90% or more of tested hepatocytes were diploid, whereas in patients with liver cirrhosis who developed HCC within 3 years the frequency histogram of nuclear DNA content was widely spread from diploid to hyperpolyploid with a small peak of triploid. Furthermore, in the latter group of patients, many of the binucleate cells had different DNA contents in each paired nucleus. In non-cancerous portions of HCC, the ploidy histogram of nuclear DNA content was widely spread from diploid to polyploid with different DNA contents of each paired nucleus in binucleate cells, without the small peak of triploid. These results suggest that the deranged cell kinetics of hepatocytes in cirrhosis may be considered to be a state of potentially high risk for the evolution of HCC, and that a patient with liver cirrhosis with such an abnormal hepatocyte DNA content should be followed up carefully for the early diagnosis of HCC.

Adult↗
PubMed1985

Alteration of ribosomes and RNA polymerase in drug-resistant clinical isolates of Mycobacterium tuberculosis.

The biochemical mechanism of resistance to kanamycin, viomycin, and rifampin in five clinical isolates of Mycobacterium tuberculosis was studied. Resistance to viomycin and kanamycin was attributed to altered ribosomes, whereas resistance to rifampin was attributed to an alteration of RNA polymerase. Ribosomal resistance was, however, not the only way of expressing resistance to viomycin and kanamycin.

Anti-Bacterial Agents↗