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Biomedical subjects

N Oshima

Publications and source records attributed to N Oshima.

At least 55 records · Page 3Linked to original sources
PubMed1987

[Partial response of lung metastases from a renal cancer treated with endogenous tumor necrosis factor].

The strong tumor-selective cytocidal action of tumor necrosis factor (TNF) has been observed in vitro and in vivo. Sato et al. have reported that it was possible to induce a primed state of TNF triggering by injection of purified protein derivative (PPD) even a long time after BCG sensitization, suggesting that this treatment could be applied to human patients. In the present study, we achieved a partial response of a metastatic lesion in a patient with renal cancer by the induction of endogenous TNF by PPD and OK-432 (a streptococcal preparation). This study suggested the possible application of this therapy to also patients with malignant tumor which are highly resistant to any conventional antitumor therapy.

Biological Products↗
PubMed1986

Action of melanin-concentrating hormone (MCH) on teleost chromatophores.

The in vitro effects of synthetic salmon melanin-concentrating hormone (MCH) on chromatophores of four teleost species were studied. In the erythrophores of the platyfish (Xiphophorus maculatus) and the swordtail (Xiphophorus helleri), and in the xanthophores and amelanotic melanophores of the medaka (Oryzias latipes), pigment aggregation took place in response to MCH even in the absence of Ca2+. In contrast to this, the leucophores of the medaka responded to MCH by the pigment dispersion but only when Ca2+ was present. The motile iridophores of the blue damselfish (Chrysiptera cyanea), which play a predominant role in coloration and its changes, were not affected by the hormone. Pharmacological studies employing various blocking agents suggest that the pigment-aggregating action of MCH is probably mediated through specific receptors possessed by the erythrophores, xanthophores, or amelanotic melanophores, while the pigment-dispersing action on the leucophores might be revealed through the receptors for melanophore-stimulating hormone (MSH).

Animals↗
PubMed1986

Control of chromatophore movements in dermal chromatic units of blue damselfish--II. The motile iridophore.

The mechanism regulating the movements of the unique motile iridophores of the blue damselfish, Chyrsiptera cyanea, was studied. The reaction in which the cells become reflective to light rays of longer wavelength, i.e. from the near u.v. region to the green region, was designated as the "coloring response", while the reverse process was labeled the "clearing response". Both nervous stimuli and adrenergic agonists gave rise to the coloring response, which could be antagonized by alpha adrenolytic agents. The clearing response was accelerated by adenosine and inhibited by theophylline. None of the hormonal substances tested had any effect on the motile response of the cells. It was concluded that the motile iridophores are solely under the control of the sympathetic adrenergic system, and that the co-transmitter, adenosine, may function to antagonize quickly the true transmitter-induced colored state of the cells.

Adenosine↗
PubMed1986

A comparative survey of the type of sympathetic neuro-melanophore transmission in catfishes.

The types of innervation to integumental melanophores were surveyed comparatively within the order Siluriformes. In fish or many families, pigment aggregation within melanophores was found to be under the control of adrenergic sympathetic postganglionic fibers as in other fish. In silurid catfish, on the other hand, the cells were found to be regulated cholinergically, though the fibers concerned were sympathetic postganglionic. Muscarinic cholinoceptors mediate the melanin-aggregating response. In some catfish belonging to Bagridae, Pimelodidae and Callichthyidae, the melanophores strangely possessed cholinoceptors, notwithstanding the fact that they were under adrenergic nervous control. These results were discussed in conjunction with the phylogeny of Siluriformes.

Animals↗
PubMed1986

Adenosine receptors mediate pigment dispersion in leucophores of the medaka, Oryzias latipes.

Using the medaka, Oryzias latipes (orange-red variety), the mechanisms of action on leucophores of adenosine and adenine nucleotides, including cyclic AMP, were studied. All these substances were found to be very effective in dispersing leucosomes. Their pigment-dispersing action was antagonized by methylxanthines. These substances did not aggregate leucosomes. It was concluded that leucophores possess specific binding sites for adenosine, i.e. adenosine receptors, on the cell membrane, which mediate leucosome dispersion. Further, it was shown that even the action of an established intracellular second messenger, cyclic AMP, is primarily manifested through the receptors.

Adenine Nucleotides↗
PubMed1986

Cyclic nucleotide action is mediated through adenosine receptors in damselfish motile iridophores.

Effects of cyclic nucleotides on motile iridophores were examined in the blue damselfish, Chrysiptera cyanea. All of the cyclic nucleotides tested, i.e. cAMP, 2',3'-cAMP and cGMP, accelerated the clearing response of the cells even at concentrations of 10(-5) or 10(-4) M. The action of these nucleotides was effectively antagonized by methylxanthines. These results suggest that the effect of cyclic nucleotides on damselfish iridophores is mediated by adenosine receptors in a similar fashion to the action of adenosine.

Animals↗
PubMed1985

Melanin concentrating hormone (MCH) effects on teleost (Chrysiptera cyanea) melanophores.

The in vitro biological actions of synthetic chum salmon melanin concentrating hormone (MCH) on melanophores of the blue damselfish (a teleost), Chrysiptera cyanea, were studied. This cyclic heptadecapeptide stimulated melanosome (melanin granule) aggregation (centripetal migration) within melanophores at a threshold concentration of about 10(-10) M. The action of this putative hormone was not blocked by alpha- or beta-adrenoceptor antagonists. It was concluded that the effects of MCH were direct and were not mediated indirectly through the actions of adrenergic neurotransmitters released from nerve terminals. Further evidence for this view comes from the observation that, unlike the case of neurotransmitter release, melanosome aggregation in response to MCH proceeded in the absence of calcium. The possible role of MCH in the control of color change of teleost fishes is discussed.

Animals↗
PubMed1985

Receptor mechanisms in fish chromatophores--VIII. Mediated by beta adrenoceptors, catecholamines always act to disperse pigment in siluroid melanophores.

The sympathomimetic amines tested, including those of alpha and beta type, were all ineffective in arousing melanosome aggregation within dermal and epidermal melanophores of the siluroid catfish, Parasilurus asotus. Conversely, these amines unfailingly gave rise to a dispersion of the pigment. While alpha-adrenergic blocking agents had only a little influence, beta agents exhibited a strong inhibitory effect on the pigment-dispersing action of the amines. Electrical nervous stimulation failed to bring about a melanosome dispersion. It was concluded that the adrenoceptors possessed by dermal and epidermal melanophores of this species seemed to be solely of the beta-adrenergic type, mediating the pigment dispersion, and that the endogenous amines involved in the darkening reaction of animals may originate in adrenal chromaffin cells, and thus are not derived from the peripheral nervous elements.

Animals↗
PubMed1985

Control of chromatophore movements in dermal chromatic units of blue damselfish--I. The melanophore.

Mechanisms controlling pigment movements in the melanophore of the blue damselfish, Chrysiptera cyanea, were studied. Histological observations revealed that the melanophore had three-dimensionally developed processes to envelop overlying small iridophores, and thus participated in the construction of a simple dermal chromatophore unit. Nervous stimulation, catecholamines and melatonin brought about melanosome aggregation in the melanophore. The actions of the nervous stimulation and catecholamines were antagonized by alpha adrenolytic agents. A beta adrenergic agonist, metaproterenol, adenosine and adenine nucleotides, and alpha-MSH acted as pigment-dispersing agents. These results indicate that the melanophore of the present material is controlled quite orthodoxly by adrenergic nerves and endocrines, notwithstanding the fact that it has quite a unique morphology among fish species, and that its motile rate is remarkably high.

Animals↗
PubMed1985

[Study of the local use of amikacin].

Amikacin sulfate (AMK) was used against urinary tract infections (UTI) as local administration such as bladder lavage, renal pelvic lavage and vesical instillation. Forty four patients with UTI were treated by this method, 32 patients having Foley catheter indwelling in the bladder and 12 patients having drainage catheter indwelling in the renal pelvis. The overall clinical effect under UTI judgment was 3 excellent cases, 24 good, 11 fair and 6 poor, with an efficiency of 61.4%. A total of 100 bacteria, 47 gram positive, 33 gram negative, 6 anaerobes and 14 fungi, were found in the urine and bacteriological effect was 68.8% and 57.1% in single and combined bacterial infection, respectively. The serum concentration of AMK was measured in 9 patients by radioimmunoassay, and the maximum concentration was 0.38 micrograms/ml which is a low absorption rate. There were no adverse reactions during or after treatment with AMK.

Adult↗
PubMed1984

Release of ATP from adrenergic nerves controlling pigment aggregation in tilapia melanophores.

Using split fin preparations of a tilapia, Sarotherodon niloticus, release of ATP from the adrenergic melanosome-aggregating nerve was studied. Associated with the melanosome aggregation, an apparent release of ATP was detected following electrical nervous stimulation. ATP-release increased with increases in stimulus intensity. Spontaneous release of a small amount of ATP was also detected. It was concluded that ATP may be liberated as a co-transmitter along with the true one, norepinephrine, and it may function to help melanophores recover from the effect of the latter, thus enabling fish to change their hue very rapidly.

Adenosine Triphosphate↗
PubMed1982

Electrophoretic movement of fertilized sea-urchin eggs.

The eccentric shift of the sea-urchin egg within the fertilization membrane under an electric field was analysed by measuring the electrophoretic mobility of the isolated fertilization membrane and that of the egg deprived of the fertilization membrane. In addition, the migration speed of the egg proper was measured within the fertilization membrane under the conditions that: either (1) the movement of the whole egg was arrested, or (2) protamine sulphate was adsorbed on the fertilization membrane to reduce its mobility. The results led to conclusions that: (1) both the fertilization membrane and the egg cell with the hyaline layer are negatively charged; (2) movement of the normal fertilized eggs is due mainly to the surface charge of the fertilization membrane; and (3) the eccentric position of the egg within the fertilization membrane is due to migration of the egg proper, which is independent of the movement of the whole egg.

Animals↗
PubMed1980

Plasma cyclic AMP level in psychiatric diseases of childhood.

Determinations were made of the plasma cyclic AM level to examine its relationship with hyperkinesis (Werry-Weiss-Peters Activity Scale, WWPAS) and other features of mental disorders in 80 children, of whom 21 had early infantile autism, 15 hyperkinetic mental retardation, 12 minimal brain dysfunction and 32 Down's syndrome. In autistic and hyperkinetic mentally retarded children, the plasma cyclic AMP levels were higher than in normal children and were positively correlated with the WWPAS score. In children with minimal brain dysfunction, the plasma cyclic AMP level was significantly lower than in normal children and was not correlated with the WWPAS score. In children with Down's syndrome, the plasma cyclic AMP level was somewhat higher than in normal children.

Adult↗
PubMed1978

A rapid, simple determination of plasma cyclic AMP.

Plasma cyclic AMP content was determined without being extracted, using binding protein obtained from rat liver. EDTA was suitable as an anticoagulant for cyclic AMP estimation. Cyclic AMP further added to EDTA plasma was able to be estimated. The estimated values by plasma dilution were almost the same as the expected values. It was thought that the direct assay was useful for determination of plasma cyclic AMP. Isoproterenol (50 microgram/kg, iv) produced an increase of plasma cyclic AMP level accompanied with a decrease of blood pressure and an increase of heart rate in anesthetized dogs. Cyclic AMP level of peripheral venous plasma was 18.6 +/- 1.32 p mole/ml in human (N=25), 21.6 +/- 3.04 P mole/ml in dogs (N=7) and 50.6 +/- 4.59 p mole/ml in rabbit (N=9). Plasma cyclic AMP level of rabbit was higher than those of human and dog.

Animals↗