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Biomedical subjects

H Amano

Publications and source records attributed to H Amano.

At least 271 records · Page 15Linked to original sources
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

Mechanism of kyotorphin-induced release of Met-enkephalin from guinea pig striatum and spinal cord.

The characteristics of kyotorphin (Tyr-Arg)-induced release of Met-enkephalin from the striatum and the spinal cord of guinea pig were determined by superfusing the slices in vitro and then carrying out radioimmunoassays. Depolarization by 50 mM K+ induced a marked release of Met-enkephalin-like immunoreactivity. The potassium-induced release of Met-enkephalin was calcium-dependent. In preparations from a striatum, the addition of kyotorphin to the superfusion medium produced a concentration-dependent increase in Met-enkephalin. The kyotorphin-induced release of Met-enkephalin was calcium-dependent and was abolished by tetrodotoxin. Similar effects of kyotorphin were seen in the spinal cord preparations. Electrical field stimulation of the striatal slices at a frequency of 10 Hz also evoked significant and calcium-dependent increases in the release of Met-enkephalin and markedly enhanced the kyotorphin-induced release of Met-enkephalin, as compared to the controls not given field stimulation. These results suggest that kyotorphin depolarizes the so-called enkephalinergic neurons and releases Met-enkephalin from nerve terminals. This effect of kyotorphin may be a possible mechanism related to the manifestation of analgesia.

Animals↗
PubMed1981

Isolation of cowpox virus clones deficient in production of type A inclusions: relationship to the production of diffusible LS antigen.

Cowpox virus clones (A- clones) deficient in production of type A inclusions were isolated from two cowpox strains, Amsterdam and 53. These clones did not differ from their parents in major markers such as pock morphology in chorioallantoic membranes and pathogenicity in the rabbit skin. However, the LS antigens induced by A- clones developed precipitin lines in agar gel diffusion tests, while the antigens from their parents failed to precipitate. Immunofluorescence and agar gel diffusion tests revealed that antigens detectable by antisera against purified type A inclusions and LS antigens were closely related to each other. These findings suggest that the A- clones might be variants of cowpox virus which have lost the ability to assemble LS antigens into type A inclusions.

Animals↗
PubMed1981

[Studies on acid glycosaminoglycans in rabbit uterine cervix and body (author's transl)].

We aimed to measure acid glycosaminoglycans (aGAG) and its composition in nonpregnant and immediately postpartum rabbits uterine cervix and body. aGAG was extracted from the uterine tissues by the modified method of K. Anno (1964) and determined by the carbazole method (Bitter, 1962). Component of aGAG were separated and identified by electrophoresis (0.3 M calcium acetate, veronal buffer, 0.1 M veronal -0.15 M ammonia water, 0.2 M ZnSO4) using acetate cellulose strips. aGAG from uterine cervix and body were separated in three bands which we considered to be hyaluronic acid, heparan sulfate and chondroitin sulfate. Hyaluronic acid was dominant in the cervix, on the other hand the components of aGAG without hyaluronic acid were dominant in the body. This compositional changes were also demonstrated by histochemical digestion test and metachromasia method. We considered these changes as a sign of cervical ripening at term pregnancy.

Animals↗
PubMed1981

Fibrin-degradation products in falciparum malaria.

A fatal female case of cerebral falciparum malaria who was accidentally, artificially and directly infected in Japan through nursing an imported falciparum malaria was experienced. These observations raised a question as to whether the disseminated intravascular coagulation (DIC) would occur in falciparum malaria. Then, 84 Congolese patients with uncomplicated falciparum malaria were studied on the coagulation. Serum fibrin-degradation products (FDP) levels were only slightly raised (10-40 microgram/ml) in 4 cases out of 84 (5%). Thrombocytopenia, elongation of prothrombin time and low fibrinogen concentration were found in 24 out of 57 (42%), in 11 out of 47 (23%) and in 11 out of 46 (24%), respectively. Relations between FDP level and the other observations were not significant. It is suggested that there is no evidence of intravascular coagulation at least in uncomplicated falciparum malaria.

Adult↗
PubMed1981

[Measurement of 222Rn in air using liquid scintillation techniques (author's transl)].

A simple method for the measurement of 222Rn in air was established. At first step radon daughters in air were eliminated from air by suction using glass fiber filter, after that the air were introduced directly to the scrubbing bottle filled with scintillator based on toluene and bubbled until the concentration of 222Rn in the liquid scintillator reached equilibrium state. Then 120ml of the bubbled liquid scintillator were sealed in the teflon vial for the measurement of radioactivity. After the radioactive equilibrium between 222Rn and its daughters were reached, the radioactivity were measured by the low background liquid scintillation counter. The detection limit of 222Rn in air by this method was 3 x 10(-3) Bq/l air (8 x 10(-14)Ci/l air). Though alpha spectrometry by multi-channel analyzer was also achieved, the integral counting method was used more effectively. This method was effectively applied to determine the relatively high concentration of 222Rn in air.

Air↗
PubMed1979

A novel analgesic dipeptide from bovine brain is a possible Met-enkephalin releaser.

It is generally accepted that morphine exerts its analgesic effect by binding to specific opiate receptors in the brain and spinal cord. Since Hughes et al. isolated and identified two endogenous pentapeptides, Met- and Leu-enkephalin, from the brain and found that they acted as agonists at opiate receptors, alpha-, beta- and gamma-endorphins, larger peptides than enkephalins and having morphine-like activity, have been identified in either the brain or pituitary of various species. Several studies have demonstrated that enkephalins possess analgesic properties and that they are distributed in the pain-mediated pathways in the central nervous system. These findings suggest that enkephalins are important neurotransmitters or neuromodulators regulating pain transmission. We now report the isolation of a novel substance which has a Met-enkephalin releasing action. Our findings suggest the possibility of a regulating mechanism for the release of endogenous opioid peptides, especially Met-enkephalin.

Analgesia↗
PubMed1979

Comparison of the analgesic effects of various opioid peptides by a newly devised intracisternal injection technique in conscious mice.

To determine accurately the central analgesic effects of opioid peptides, we devised a special technique for intracisternal administration of drugs to conscious mice. When this method was utilized we found that a series of endogenous opioid peptides and enkephalin analogues, (D-Ala2,Met5)-enkephalinamide and (D-Met2,Pro5)-enkephalinamide produced dose-related analgesic effects, as determined by the tail pinch test. These effects were antagonized by pretreatment with naloxone 0.5 mg/kg s.c. This technique should be a most accurate one for the determination of central analgesic effects of various drugs in conscious mice.

Animals↗
PubMed1979

Adrenergic innervation in the Eustachian tube of guinea pigs.

We have succeeded in demonstrating for the first time adrenergic innervation in the Eustachian tube of guinea pigs. The approach was histochemical using the fluorescence method with glyoxylic acid. There was an apparent regional variation with a greater number of axon terminals in the pharyngeal area of the Eustachian tube as compared to the tympanic area.

Adrenergic Fibers↗
PubMed1979

Orthopoxvirus strains defective in surface antigen induction.

Various strains of vaccinia, variola, whitepox, monkeypox and cowpox viruses were examined for their capacity to induce a specific early antigen detectable on the surface of infected cells. The Elstree strain of vaccinia, two strains of variola minor and white variants of cowpox and monkeypox viruses lacked the capacity to induce the antigen. Variation of the parent cowpox and monkeypox viruses to white variants was always accompanied by the loss of the antigen-inducing capacity.

Animals↗