Search PubMed⌕ Search

Biomedical subjects

T Sekine

Publications and source records attributed to T Sekine.

At least 253 records · Page 14Linked to original sources
PubMed1982

Post-gamma globulin : tissue distribution and physicochemical characteristics of dog post-gamma globulin.

An animal model (dog) was established to investigate physicochemical and biological parameters of a basic low molecular mass protein---post-gamma globulin (p-gamma). In this study the distribution of this 11 000 daltons (11 kdaltons) protein was determined in extracts of the number of tissues. Extracts of parotid gland, brain and kidney contained high amounts of "free" p-gamma globulin (11 kdaltons). Two higher molecular mass forms (34k and 27 kdaltons) of this protein were demonstrated in the kidney and brain extracts. Extracts of ovary and uterus were devoid of the 27 k moiety and kidney extracts lacked the "free" p-gamma globulin (11k). These studies indicate that p-gamma globulin may be a part of a much larger molecule or that p-gamma globulin may be associated with another yet unknown protein. These findings may be important for clinical and pathological studies in human kidney and central nervous system (CNS) diseases.

Animals↗
PubMed1982

Significance of sustained gastric hypersecretion by the emulsified histamine solution.

Experimental production of gastric and duodenal ulcers was investigated in dogs by administration of histamine emulsified in Freund's incomplete adjuvant. Acid secretory responses were also checked. The results are as follows: Intramuscular administration of 10 mg/day of the emulsified histamine solution caused sustained gastric hypersecretion due to gradual liberation of histamine but produced no apparent side effects. However, neither gastric nor duodenal ulcer was observed within 2 months with the dosage of 10 mg/day. These results suggest that intramuscular administration of the dosage of 10 mg/day within 2 months would be a valuable means to elucidate the pathogenesis of ulcer under the sustained gastric hypersecretion.

Animals↗
PubMed1982

"Sand bar" of actinoid and neighboring elements in a chart of nuclides.

Inspection of a chart of nuclides reveals a "sand bar" of actinoid and neighboring elements when a suitable half-life level is chosen. A bay of alpha-instability lying between the nuclides of neutron magic number 126 and the beta-stability line in the actinoid group is a characteristic feature in this area. Calculation shows that fairly good agreement is obtained between the measured half-lives and those derived theoretically.

Actinoid Series Elements↗
PubMed1982

[Experimental induction of yolk sac tumor in rat (author's transl)].

Unlike those experiments described in the previous several reports, a carcinogen was given to pregnant rats in our experiment to induce a tumor similar to yolk sac tumor which often occurs in human cases, aiming at contribution to establishment of an experimental model. Using Wister rat on the 10th day of gestation, ater removal of the fetus, the yolk sac was extracted out of the uterus, and a carcinogen was administered to it. Induced tumor was examined morphologically. By the 16th week after experiment, tumor was induced in 70% out of rats treated. The tumor volume was varied from a bean to a thumb tippize. Histologically, most of them were considered to be teratoma. But in 30% of them, human pure-type yolk sac tumor or the tumor similar to it were observed. Reticular and endodermal sinus or polyvesicular vitelline patterns were also clearly observed. Presence of hyaline body by PAS-staining and AFP by fluorescent antibody method were confirmed.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1981

Multiple forms of human intestinal alkaline phosphatase: chemical and enzymatic properties, and circulating clearances of the fast- and slow-moving enzymes.

Two forms of alkaline phosphatase (orthophosphoric monoester phosphohydrolase (alkaline optimum, EC 3.1.3.1) have been purified from human small intestine by column chromatography on DEAE-cellulose and tyraminyl derivative affinity gel, and by preparative disc gel electrophoresis. Intestinal phosphatases were electrophoretically separated into two components, fast- and slow-moving enzymes, with apparent molecular weights of 140000 and 168000 and with subunit weights of 68000 and 80000, respectively. Analyses of carbohydrate and amino acid revealed marked differences in the two enzymes. Enzymatic properties and affinities for an anti-blood group antibody were also found to differ. Papain digestion released a hydrophobic small peptide from the slow-moving enzyme and its enzymatic properties resembled those of the fast-moving enzyme. Circulating clearance (T1/2) of the slow- and fast-moving enzymes from adult intestine was found to be 7.5 h and 1.3 h, respectively; that of fetal intestinal enzyme was 2.8 h. Sialidase, sialidase/beta-galactosidase, or sialidase/beta-galactosidase/N-acetyl-beta-glucosaminidase treatment of the fetal enzyme reduced the value to about 40 min. Further, digestion with alpha-fucosidase, alpha-mannosidase or both restored it to nearly the original level. Organ distribution of injected 125I-labelled enzymes indicates that the desialylated hepatic enzyme was selectively distributed in liver, while the degalactosylated intestinal enzyme was incorporated into liver lymph fluid, and small intestine. These results suggest that the pathway of circulating clearance of alkaline phosphatase has several routes.

Adult↗
PubMed1981

A new fluorometric ultramicro determination of serum cystine aminopeptidase using an aminocoumarine derivative.

A rapid and sensitive fluorometric rate assay of serum cystine aminopeptidase is described using a novel fluorogenic substrate, 7-S-benzyl-L-cysteinyl-4-methylcoumarinylamide. The proposed method enabled us to determine cystine aminopeptidase activity in one minute using 10 microliter of serum. The assay was shown to be free from error due to the adsorption of the substrate to serum albumin. The values obtained by this method gave good correlation with those obtained by the conventional method of Watson [6].

Aminopeptidases↗
PubMed1981

Histologic stromal reaction of the host with gestational choriocarcinoma and its relation to clinical stage classification and prognosis.

One of the factors determining the prognosis of choriocarcinoma is the stromal reaction of the host. We have been interested in the histologic findings of this reaction, and we studied the relationship between the CPV classification, which had been used in our department, and our clinical stage. There was no relation of stage distribution to CPV classification. For instance, Type C, which has a strong stromal reaction, did not display any parallel relation with stage. When mortality rates and stages are compared, however, it is noteworthy that the mortality rate for Type C cases is small in Stage I and is less than 50% even in Stage III, in which metastasis is considered to be inevitable; thus, more than half of the cases are cured. On the contrary, Types P and C tend to be associated with high mortality rates even in Stages I and II, in which metastasis is not certain.

Choriocarcinoma↗
PubMed1981

Light chain phosphorylation alters the N terminal structure of gizzard myosin heavy chain in an ATP dependent manner.

It was shown that the heavy chain structure was altered by the phosphorylation of light chain in gizzard myosin. Phosphorylated myosin was compared with unphosphorylated myosin with respect to the chymotryptic fragmentation with or without ATP in the medium. The rise and fall of the fragments were well explained by the reconstitution model for unphosphorylated myosin (Okamoto, Y., et al. (1980) J. Biochem. 88, 361-371). A specific cleavable site in the myosin head was completely abolished by the phosphorylation of light chain. The effect of phosphorylation on the site could be observed in the absence of ATP but not in its presence. These results strongly suggest the possible integrity of the site, 5K daltons apart from the masked N terminus, for the physiological activity of gizzard myosin.

Adenosine Triphosphate↗
PubMed1981

N-terminal region of gizzard myosin heavy chain is critical for the ATPase activity.

Two different HMM species of gizzard myosin were prepared under conditions such that the phosphorylation of light chain was fully maintained. They were different in the N-terminal structure of the heavy chain but not in the light chain composition. A significant decrease in the Mg2+-ATPase activity was observed in one class of HMM which was proteolytically cleaved intramolecularly at site 1, 5 K daltons from the masked N terminus. Another class of HMM without the cleavage at site 1 showed ATPase activity similar to that of myosin. The decrease in ATPase activity was not caused by denaturation since similar amounts of initial burst of Pi liberation were observed with both HMMs and myosin. Kinetic and substructure analyses of HMM revealed that the activity change depended solely on the cleavage at site 1. The N-terminal region of gizzard myosin heavy chain may thus have an important role in maintaining the active site structure.

Adenosine Triphosphatases↗
PubMed1981

The effect of cleavage at site 1 of gizzard HMM in the interaction with skeletal muscle actin.

Two different classes of gizzard heavy meromyosins (HMMs) were prepared from phosphorylated myosin by chymotryptic digestion in the presence and absence of ATP and were compared with respect to their actin-activated Mg2+-ATPase reactions. One class of HMM, named HMM(+), had a cleavage at site 1 in the N terminal portion of the heavy chain and the other class of HMM, named HMM(-), had no cleavage at this site. Maximum turnover rate (Vmax) of the skeletal acto-gizzard HMM Mg2+-ATPase reaction was obviously different between HMM(+) and HMM(-). The Vmax value of HMM(+) was 2.5-fold larger than that of HMM(-). On the other hand, the apparent association constants (Ka) of skeletal muscle actin for both HMMs which were deduced from double reciprocal plots (v-1 versus [actin]-1) seemed to be identical. The difference in Vmax value was attributed to the cleavage at site 1 since a following chymotryptic cleavage of HMM(-) at site 1 caused a 2.5-fold increase in the Vmax value. That site 1 in the N terminal portion of the gizzard myosin heavy chain was the key locus for the actin-myosin interaction was shown in addition to our previous finding of the effects of cleavage at site 1 on the ATPase activity and nucleotide binding ability of gizzard HMM (Okamoto, Y. & Sekine, T. (1981) J. Biochem. 90, 833-843; 843-949).

Actins↗