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Biomedical subjects

S Katayama

Publications and source records attributed to S Katayama.

At least 451 records · Page 25Linked to original sources
PubMed1982

A binding-protein for aldosterone in human plasma.

Equilibrium dialysis of fresh human plasma revealed that aldosterone was bound to plasma proteins other than albumin. The apparent association constant of aldosterone to nonalbumin plasma proteins was one order of magnitude larger than that reported for aldosterone to corticosteroid-binding globulin (CBG), while its binding capacity was smaller than that of CBG. Bound aldosterone was not completely dissociated when the binding capacity of CBG was saturated with a large amount of cortisol. The addition of aldosterone under these experimental conditions further displaced its binding to nonalbumin plasma proteins. Progesterone inhibited binding of aldosterone but not to the same extent as cortisol did. Column electrophoresis of dialyzed plasma demonstrated, in addition to the peak of aldosterone binding to CBG and albumin, a peak of aldosterone comigrating with alpha 1-globulin. When the fractions containing this peak were pooled and subjected to equilibrium gel filtration on Sephadex G-200, bound aldosterone was eluted between CBG and albumin. Desialylated plasma also showed a peak of aldosterone binding different from the peaks corresponding to CBG and albumin on gel filtration. This aldosterone-binding protein was a glycoprotein precipitable with 60% saturation of ammonium sulfate and completely inactivated by heating at 60 degrees C for 30 min. These results suggest the existence of an aldosterone-binding protein in human plasma different from CBG, albumin and alpha 1-acid glycoprotein.

Binding, Competitive↗
PubMed1982

Effect of dietary sodium ascorbate on 1,2-dimethylhydrazine- or methylnitrosourea-induced colon carcinogenesis in rats.

The effect of dietary sodium ascorbate (SA) on colon carcinogenesis evoked by 1,2-dimethylhydrazine (DMH) or N-methyl-N-nitrosourea (MNU) was studied in female F344 rats. Animals were fed diets containing 0, 0.25 and 1% of SA and given s.c. a single dose of 150 mg DMH/kg body wt., 10 weekly s.c. injections of 20 mg DMH/kg body wt. or intra-rectal administration of 2 mg MNU, twice a week for 2 weeks. The incidence of colon and kidney tumors was lower in rats fed the 0.25 or 1% SA and treated with a single dose of DMH than in the animals fed the diet without SA; however, the tumour incidences did not differ between the SA- and control diet-fed animals and treated with multiple doses of DMH or MNU.

1,2-Dimethylhydrazine↗
PubMed1982

2-Hydroxyestrone suppresses and 2-methoxyestrone augments the preovulatory prolactin surge in the cycling rat.

The nonuterotropic metabolite of estradiol, 2-hydroxyestrone, administered at noon of proestrus to four-day cycling rats, abolishes the preovulatory prolactin rise in a large percentage of animals tested. In animals synchronized with exogenous estradiol, 2-hydroxyestrone universally induced a long delay in the prolactin surge. The principal metabolite of 2-hydroxyestrone, 2-methoxyestrone, given at noon of proestrus, significantly augments the magnitude of the preovulatory prolactin rise possibly by inhibiting the formation of endogenous 2-hydroxyestrogens in the brain. The results obtained are consistent with the concept of a physiological function for 2-hydroxyestrogens as estrogen antagonists in the CNS.

Animals↗
PubMed1982

Altered cyclic AMP responsiveness to vasopressin in rat renal medullary dispersed cells by acute elevation of endogenous vasopressin.

Medullary and cortical tubular cells were prepared from rat kidneys with collagenase treatment. Arginine vasopressin (AVP) stimulated cyclic AMP production both in medullary and cortical cells with a dose-response relationship at concentrations ranging from 10 microU/ml to 10 mU/ml, whereas parathyroid hormone (PTH) and calcitonin did only in the latter. Using this medullary cell system, effects of acute changes in endogenous plasma AVP levels in vivo on its cyclic AMP responsiveness to AVP (10 mU/ml) in vitro were examined. Acute elevation of plasma AVP levels induced by ip injection of 20% (w/v) polyethylene glycol-isotonic saline solution 3 h prior to sacrifice resulted in a 33% decrease in cyclic AMP responsiveness to AVP (desensitization). More prolonged elevation of plasma AVP levels by water restriction for 48 h, on the other hand, increased the responsiveness by 38 to 81%, which was restored to basal levels by ad libitum intake of water for another 48 h (positive feedback regulation). These maneuvers did not alter the cyclic AMP responsiveness to PTH (10 micrograms/ml) in cortical cells. The results suggest that AVP-stimulated adenyl cyclase in rat renal medulla may be regulated by changes in endogenous AVP levels even within the physiological range.

Animals↗
PubMed1982

Influence of chronic ethanol consumption on the metabolism and carcinogenicity of tobacco-related nitrosamines.

The effect of chronic ethanol consumption by Syrian golden hamsters (SGH) on the carcinogenicity and target tissue metabolism of N-nitroso-pyrrolidine (NPYR) and N'-nitrosonornicotine (NNN) has been examined. Ethanol-consuming hamsters treated with NPYR developed more nasal cavity and tracheal tumours than controls. Ethanol consumption did not affect the carcino-genicity of NNN. When the metabolism of NPYR and NNN by isolated tracheal rings was examined, it was observed that tracheal rings isolated from ethanol-consuming SGH metabolized NPYR at a higher rate than similar preparations from control animals. In contrast, no differences in the rates of metabolism of NNN were observed.

Alcoholism↗
PubMed1982

Prostate adenocarcinoma in rats: induction by 3,2'-dimethyl-4-aminobiphenyl.

Five experiments designed for various purposes [mainly for the study of colon carcinogenesis in inbred F344 male rats given sc injections of 3,2'-dimethyl-4-aminobiphenyl (DMAB)] were reviewed as to the production and presence of neoplastic lesions of the prostate gland. The overall incidence of prostate proliferative lesions among 293 animals exposed to DMAB was 32% (95 animals). Early in situ carcinomas were present in 66 animals, larger intra-acinar carcinomas in situ in 28, and invasive carcinoma in 1. None of the control animals in these studies exhibited prostate neoplasms. The conclusion, therefore, is that DMAB can induce adenocarcinomas in the rat prostate gland.

Adenocarcinoma↗
PubMed1982

[Antitumor activity of macromomycin].

An antitumor activity of macromomycin, a polypeptide antitumor antibiotic, was tested in vitro and in vivo. The results obtained were as follows: 1) The cytostatic effect on L1210 cells in culture was identical to that of neocarzinostatin. 2) The effect of MCR on the survival of L1210 or P388 leukemia was as same level as NCS. 3) Effects of MCR were independent from the treatment schedules. 4) MCR was inactive on the survival of Lewis lung carcinoma.

Animals↗
PubMed1982

Plasminogen activator activity in mouse embryos cultured on decidual cell monolayers.

The nature of proteolytic activity in the mouse blastocyst was investigated in vitro using cell monolayers as a substrate. Blastocysts obtained from mice on day 4 of gestation were placed directly on various types of cell monolayers. The embryos had hatched at 34 hrs, attached at 45 hrs, and at 56 hrs of culture they formed trophoblast outgrowths by displacing the underlying monolayer cells. Because blastocysts developed equally well on all types of cell monolayers tested, a decidual cell monolayer was used in all the following experiments. The plasminogen activator activity in blastocysts was examined using the fibrin-agar overlay assay. There was a strong relationship between the levels of activity and the extent of trophoblast outgrowth. At the hatching stage, 20% of the embryos showed fibrinolysis, whereas 86% showed clear fibrinolysis at the trophoblast outgrowth stage. After the loss of invasiveness, only 32% of them showed fibrinolysis. Lysed zones surrounding trophoblast always extended beyond the area which displaced the previously occupied cell monolayer. We never observed a clear zone (halo) between the trophoblast and monolayer cells nor cytolytic activity inside the fibrinolytic zone until the embryos had lost their invasive nature.

Animals↗
PubMed1981

Amylase-producing lung cancer: case report and review of the literature.

A case of hyperamylasemia with lung cancer is described. Macroamylasemia was excluded by a normal amylase/creatinine clearance ratio and by a sedimentation constant obtained by sucrose density gradient centrifugation. Positive immunofluorescent staining of tumor cells with a specific antibody against human salivary amylase and significant amylase activity in the primary tumor and metastases support the hypothesis of independent production of amylase by the lung tumor. Cellulose--acetate membrane electrophoresis demonstrated three bands of amylase activity. The major component corresponded to normal salivary amylase in electrophoretic mobility, isoelectric point and molecular size. The minor bands, one of which occupied about 10% of the total amylase activity in serum, urine and tissue homogenates, demonstrated a lower electrophoretic mobility and a more acidic isoelectric point. Gel filtration and electrophoresis disclosed that these minor bands were derived from an amylase isozyme with a larger molecular size than that of normal salivary amylase. The results suggest ectopic tumor production of heterogenous amylase isozymes, with the larger form being secreted into the circulation.

Adenocarcinoma, Papillary↗
PubMed1981

[Clinical evaluation of hyperglucagonemia in patients with myotonic dystrophy (author's transl)].

In order to clarify the possible participation of glucagon in glucose intolerance in myotonic dystrophy, six patients with myotonic dystrophy were examined. Three out of the six patients had an abnormal oral glucose tolerance curve. Two had frank diabetic glucose tolerance curves and the other had a high glucose value at 30 min after glucose loading, which fell beyond the normal range (Mean +/- 2 S.D.). Total insulin response to oral glucose, calculated as insulin area, was significantly exaggerated (p less than 0.01 vs control value). In addition to these results, hyperglucagonemia was observed throughout the test in two patients with myotonic dystrophy. In the arginine infusion test, insulin response was not so exaggerated but plasma glucagon was significantly higher (p less than 0.05 vs control value) at each 30, 45, 60 minutes after arginine infusion, and the mean glucagon area under the curves was significantly greater (p less than 0.05 vs control value). None of the myotonic patients showed growth hormone or cortisol excess during an arginine infusion and/or insulin tolerance test. Three patients with myotonic dystrophy who had abnormal glucose tolerance curves showed absolutely or relatively high glucagon levels and exaggerated response to arginine infusion. These findings suggested that hyperglucagonemia might contribute to the appearance of glucose intolerance in myotonic dystrophy.

Adolescent↗
PubMed1981

The effect of disulfiram on the carcinogenicity of 3,2'dimethyl-4-aminopbiphenyl in Syrian golden hamsters and rats.

3,2'-Dimethyl-4-aminobiphenyl (DMAB) was administered s.c. to Syrian golden hamsters and CDF rats with and without disulfiram in the diet. In a group of male hamsters given only weekly injections of DMAB over a period of 18-22 months, 10 of 25 hamsters developed adenocarcinomas of the small or large intestine. Three had carcinomas in both the large and small intestine, 3 had only colon carcinomas and 4 only small intestinal carcinomas. In the group fed disulfiram and carcinogen, 10 of 25 hamsters developed adenocarcinomas of the colon, but only one carcinoma of the small intestine occurred. Furthermore, the appearance of intestinal tumors was delayed, Urinary bladder carcinomas occurred in both groups exposed to DMAB, with the appearance being slightly delayed in the group also receiving disulfiram. In male rats given DMAB s.c. once a week for 10 months, the addition of disulfiram in the diet reduced the incidence of cancers of the small intestine, similar to the effects of hamsters, but resulted in the occurrence of a small number of bladder cancers. An unusual occurrence was the development of prostatic carcinoma in rats given DMAB.

Aminobiphenyl Compounds↗
PubMed1981

Enhancement of hepatocarcinogenesis by sequential administration of chemicals: summation versus promotion effects.

A comparative study was made of the sequential administration of the liver carcinogen, diethylnitrosamine (DEN), or the liver tumor promoter, phenobarbital, given after the liver carcinogen, N-2-fluorenylacetamide (FAA). The effects of the second carcinogen on preneoplastic cellular lesions induced by the first carcinogen were comparable to the effects of the promoter. In addition, both sequential exposures enhanced the ultimate carcinogenic effect, although the combination of FAA followed by DEN resulted in a greater number of malignant neoplasms. Thus, enhancement of carcinogenesis by a second chemical cannot be used by itself as evidence of a promoting action. Approaches to the more precise definition of promoters include exclusion of genotoxicity, identification of epigenetic mechanisms and lack of a summation effect with administration prior to genotoxic carcinogens.

2-Acetylaminofluorene↗
PubMed1981

Five-year follow-up study of patients with persistent vegetative state.

One hundred and ten patients with persistent vegetative state, were followed up for a period of five years from 1973 to 1978. Seventy-three per cent of the patients died during the period while about 10% of them recovered partially from the vegetative state. Among the recovered patients, only three became able to communicate, but two of these are not independent for their daily activites. Reactivity and clinical symptoms of 30 survivors were examined, but no great changes occurred during the last two years of the study.

Adult↗
PubMed1981

Nature of the immunoreactive neurophysins in ectopic vasopressin-producing oat cell carcinomas of the lung. Demonstration of a putative common precursor to vasopressin and neurophysin.

In an attempt to delineate the nature of the immunoreactive neurophysins in oat cell carcinomas of the lung with ectopic vasopressin production, tumor neurophysins were characterized by gel filtration and by electrophoresis. In all of the five tumor tissues, activities of both vasopressin and nicotine-stimulated neurophysin (NSN) determined by radioimmunoassay were demonstrated. A small amount of oxytocin as well as estrogen-stimulated neurophysin was detected in three of the tissues. When tissue extract was subjected to Sephadex G-50 gel filtration in 0.2 N acetic acid, the major portion of immunoreactive NSN emerged in the fractions corresponding to the molecular size of 10,000. The migration pattern of NSN in these fractions on electrophoresis was qualitatively the same as that of NSN extracted from human posterior pituitary glands. In addition to this major neurophysin, immunoreactive NSN with the molecular size of 20,000 was consistently demonstrated in three tumor extracts. This high molecular weight form of neurophysin represented 6.5--8.7% of total NSN immunoactivities in each tumor extract and its elution profile was not changed when analyzed under denaturating conditions in 6 M guanidine hydrochloride. On electrophoresis, it migrated near the gamma globulin region; however, the peak was broad suggesting that it consists of more than two different molecular populations. A substantial portion of the high molecular weight NSN appears to be a glycoprotein judging from its binding to concanavalin A. When the high molecular weight from of neurophysin was incubated with trypsin, essentially all of the activities were converted into NSN with the molecular size of 10,000. Moreover, an equimolar amount of vasopressin was liberated after the treatment, the elution pattern of which closely resembled that of synthetic arginine vasopressin. When a lower concentration of trypsin was used, some of the 20,000-dalton neurophysin exhibited activities of both NSN and vasopressin. Since the antivasopressin serum used in this study appeared to be directed toward the ring portion side of vasopressin, these results suggest that this 20,000-dalton neurophysin is, in all probability, a common precursor to vasopressin and neurophysin, and that vasopressin may be located in the middle of the precursor molecule.

Aged↗