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Biomedical subjects

Y Hama

Publications and source records attributed to Y Hama.

At least 91 records · Page 5Linked to original sources
PubMed1991

Chromosomal insertion and amplification of human papillomavirus 16 DNA sequences in a cell line of argyrophil small cell carcinoma of the uterine cervix.

The chromosomal location of human papillomavirus (HPV) 16 DNA sequences integrated in a cell line derived from argyrophil small cell carcinoma of the uterine cervix was determined by means of fluorescence in situ hybridization (FISH). The HPV 16 DNA sequences were integrated near a fragile site and the location of the c-myc oncogene at 8q24.1. Amplification of the integrated viral sequences resulted in an abnormally banded region. The amplified HPV 16 DNA sequences were also detected in every interphase nucleus by FISH.

Carcinoma, Small Cell↗
PubMed1991

[The interactive effects of comparative advertising on brand and company image change].

The purpose of the present study was: 1) to investigate the effects of two types of comparative advertising--Merit-type (emphasizing positive aspects of their own brand) and Demerit-type (pointing out negative aspects of the rival brand); and 2) to find an effective strategy against comparative advertising of a rival company. Subjects were shown advertisements, and were then asked to evaluate those advertisements (17 items), the brands and company images (3 items) for these two companies. The results are as follows: Comparative advertising, especially of the Demerit-type, was the most conspicuous type of advertising, which also had a significant negative effect on the perception of rival brands. However, this type of advertising also had a negative effect on his own advertising, the brands advertised, and the company itself. Furthermore, it was found that when a rival company uses Demerit-type advertising, it is better not to respond by the same type, but to respond by Merit-type advertising. In such a situation, positive image of his own brand and company become significantly higher.

Advertising↗
PubMed1990

[The effects of impolite computer messages on workers].

The purpose of this study was to clarify the effects of computer messages of varying degrees of politeness on subjects' task performance, mental state, and attitude toward computers. The task of subjects in the experiment was to type characters into the computer. When subjects made an input mistake or exceeded the time-limit, or required aid (used the HELP key), a message was given by the computer to which subjects had to reply by pressing either the "Shut up!" button or the "I am sorry" button. Before and after the experiment subjects were required to answer a questionnaire concerned with their image and attitude toward computers and the degree to which the task of typing is unpleasant. The main results were: 1) Subjects who received impolite messages felt that the message was unfriendly, but felt less unpleasantness in typing than subjects who received no message. Subjects became aggressive when impolite message were given repeatedly. 2) Subjects who received impolite messages showed positive attitude change toward computers despite the impolite messages.

Adult↗
PubMed1989

Presence of a metallothionein-like protein in the bovine pineal gland.

The high concentration of zinc in the bovine pineal gland prompted us to investigate the existence of a zinc-binding protein in this organ. In this study, we report that the subcellular distribution of zinc in the bovine pineal gland is nonuniform, with the crude nuclear, mitochondrial, microsomal, and supernatant fractions having 0.264 +/- 0.038, 0.160 +/- 0.019, 0.130 +/- 0.016, and 0.287 +/- 0.010 micrograms zinc/mg protein, respectively. Furthermore, gel filtration studies using Sephadex G-75 and a 105,000 g supernatant fraction revealed two zinc binding protein peaks that bind 1.7 and 3.7 micrograms Zn++/mg protein, respectively. Furthermore, purification of the protein peak with an elution volume (ve/vo) of 2.06 on anion exchange chromatography (DEAE-A25) yielded a single protein peak which binds 10 micrograms zinc/mg protein. The comparative high performance liquid chromatographic (HPLC) profiles of the zinc-induced hepatic metallothionein isoform I (retention time = 17.39 min) and of the bovine pineal metallothionein-like protein isoform I (retention time = 17.49 min) are similar. Since zinc is a potent inhibitor of sulfhydryl-containing enzymes and receptor sites, we investigated the effects of zinc and found that it inhibited the binding of [3H]glutamate (IC 50 = 80 microM) and of [3H]spiroperidol (IC 50 = 0.6 mM) to the pineal membranes. The results of these studies are interpreted to indicate that the bovine pineal gland possesses an active and dynamic zinc homeostatic mechanism, whose precise function(s) remain(s) to be delineated.

Animals↗
PubMed1989

Status of dopamine in bovine pineal glands and the stimulation of N-acetyltransferase activity by D2-dopaminergic receptor agonists in the rat pineal glands in culture.

In a previous study, we identified in the bovine pineal gland two [3H]spiroperidol-binding sites with KD values of 0.18 and 2.1 nM and Bmax values of 37 and 630 fmol/mg protein, respectively. In this study, the status of dopamine in the bovine pineal glands was delineated further by measuring the relative concentrations of dopamine and norepinephrine and the relative concentrations of serotonin and melatonin. Furthermore, the presence of 4.0 +/- 0.6 micrograms/dopamine/gm tissue encouraged us to delineate the effects of select dopaminergic receptor agonists and antagonists on the synthesis of melatonin in vivo and on the activity of N-acetyltransferase in the rat pineal gland in culture. The acute administration of haloperidol (3 mg/kg intraperitoneally [ip]) or sulpiride (200 mg/kg ip) increased the concentration of melatonin in the pineal gland from 160.6 +/- 8.18 to 327.6 +/- 45.43 and 306.5 +/- 40.53 pg/gland, respectively. Dopamine exhibited dual effects on the activity of N-acetyltransferase, inhibiting the basal activity at 0.1 microM and stimulating it at 10 microM, and the later effect was blocked by propranolol. D2-dopaminergic receptor agonists such as bromocriptine (4.0 microM) or LY-171555 (10.0 microM) partially attenuated the norepinephrine-induced stimulation of N-acetyltransferase, and these attenuating effects were reversed by D2-dopaminergic antagonists such as haloperidol (10 microM) or domperidone (10 microM). The results of these studies are interpreted to indicate that for the synthesis of melatonin, the pineal D2-dopaminergic receptors may function independently from those of the beta 1-adrenergic receptor sites. Furthermore, the said D2-dopaminergic receptor are amenable to down regulation since the activity of N-acetyltransferase remained unaltered (0.0717 vs. 0.0729 nmol/gland/h) following chronic treatment (4 mg/kg ip/day for 30 days) with bromocriptine.

Acetyltransferases↗
PubMed1989

[Hemodynamic study of negative pressure ventilation using diaphragm pacing].

A negative pressure ventilation (NPV) by unilateral or bilateral diaphragm pacing (DP) was prepared for canine experiments. A shift from positive pressure ventilation (PPV) to NPV resulted in elevation of mean aortic pressure, increase in stroke volume and depression of mean pulmonary arterial pressure. Examination of the interaction between respiratory cycle and cardiac function during PPV, disclosed a reduction of right ventricular stroke volume and elevation of mean aortic and right ventricular end-diastolic pressure at end inspiration, compared to those at end expiration. During NPV with DP, left ventricular stroke volume, heart rate and mean aortic pressure were increased immediately after DP (immediately after inspiration) compared to those at end expiration. The experimental model of DP, in which respiratory condition could be easily altered, was considered to be useful to evaluate the effect of NPV on cardiac function.

Animals↗
PubMed1987

Characterization of [3H]cholecystokinin octapeptide binding to mouse brain synaptosomes: effects of neuroleptics.

The presence of high concentrations of both dopamine and cholecystokinin (CCK) in the striatum and in various limbic structures suggests that the CCK may not only influence dopaminergic transmission, but it also may be relevant to the psychopathology of schizophrenia and to the therapeutic effects of neuroleptics. By using a synaptosomal fraction isolated from the mouse cerebral cortex and [propionyl-3H]CCK8-sulphate ([3H]CCK8S) as a ligand, a single binding site for [3H]CCK8 with a KD value of 1.04 nM and a Bmax value of 42.9 fmol/mg protein was identified. The competitive inhibition of [3H]CCK8S binding by related peptides produced an order of potency of CCK8-sulphated (IC50 = 5.4 nM) greater than CCK8-unsulfated (IC50 = 40 nM) and greater than CCK4 (IC50 = 125 nM). The regional distribution of [3H]CCK8S binding in the mouse brain was highest in the olfactory bulb (34.3 +/- 5.6 fmol/mg protein) greater than cerebral cortex greater than cerebellum greater than olfactory tubercle greater than striatum greater than pons-medulla greater than mid brain greater than hippocampus greater than hypothalamus (12.4 +/- 2.1 fmol/mg protein). The repeated administration of haloperidol (2.5 mg/kg/tid) increased the binding of [3H]CCK8S in cerebral cortex from 31.8 +/- 1.7 to 38.9 +/- 5.2 fmol/mg protein. The varied distribution of CCK8S receptors may signify nonuniform functions for the octapeptide in the brain.

Animals↗
PubMed1987

Three subtypes of chronic schizophrenia identified using 11C-glucose positron emission tomography.

The authors used positron computed tomography (CT) and 11C-labeled glucose to measure brain glucose utilization in 20 chronic schizophrenic patients (18 men, 2 women, mean age 38) and 5 male control subjects (mean age 38). Positron emission tomography (PET) revealed at least three subtypes: hypofrontal (type A), hypoparietal (right-sided disturbance in right-handed and left-sided disturbance in left-handed patients) (type B), and normal (type C). The significant count reduction in the frontal lobe (Brodmann's area 10) in type A patients was 38%, while that in the parietal lobe (Brodmann's area 40) in type B patients was 26% in each lobe of the brain.

Adolescent↗
PubMed1986

Zinc-binding proteins in the brain.

As an essential substance, zinc is involved in maintaining the functions and/or the structures of at least 200 metalloenzymes that participate in numerous biochemical reactions, including the metabolism of proteins and nucleic acids. The steady-state concentration of zinc in the brain must be regulated firmly since both an excess and a deficiency of zinc have been implicated in neurological disorders including epilepsy. Zinc-binding proteins have been detected in the bovine hippocampus, cerebellum, and pineal gland. A metallothionein-like protein has been identified recently in the rat brain which resembles in some but not all aspects a hepatic metallothionein. The synthesis of this protein is stimulated following the administration of zinc and copper but not of cadmium. The zinc-stimulated protein incorporates 35S cysteine 24-fold higher than the native, unstimulated protein; is blocked by actinomycin D; produces two isoforms by ion exchange chromatography on DEAE Sephadex A 25 columns; and by high performance liquid chromatography, depicts a similar but not identical profile to zinc-stimulated hepatic metallothionein. Since the synthesis of this protein is stimulated following the administration of zinc and is depressed in the brains of zinc-deficient rats, it is postulated that the unbound pool of zinc may serve as one of the factors involved in regulating the synthesis of this protein. Since zinc in physiological concentrations stimulates a number of pyridoxal phosphate-dependent reactions and in pharmacological doses inhibits an extensive number of SH-containing enzymes and receptor sites for neurotransmitters, we postulate that the metallothionein-like protein in the brain may have function(s) associated with zinc homeostasis and perhaps events related to synaptic functions.

Animals↗
PubMed1986

The nullification by diazepam of haloperidol-induced increases in the level of striatal dopamine but not in the activity of glutamic acid decarboxylase.

In the therapeutic management of neuroleptic-induced tardive dyskinesia, diazepam, baclofen or gamma-vinyl-gamma-aminobutyric acid have been advocated. It has been postulated, but not proven, that the beneficial effects of these agents in tardive dyskinesia may be mediated by enhancing GABAergic transmission. In this study, it is reported that, during a 3-day withdrawal period following daily administration of 3 mg/kg of haloperidol (i.p.) for 3 weeks, the activity of glutamic acid decarboxylase in the striatum increased from 72.6 +/- 7.8 to 92.5 +/- 10.2 nmol 14CO2/mg protein/hr, and the concentration of dopamine in the striatum increased from 7.87 +/- 0.23 to 8.86 +/- 0.38 micrograms/g wet tissue. Diazepam (5 mg/kg, i.p.), given during the withdrawal period from haloperidol was able to nullify the enhancement in the concentration of dopamine but not in the activity of glutamic acid decarboxylase in the striatum. The results of these studies are interpreted to indicate that the reported beneficial effects of diazepam and GABA-mimetic agents in ameliorating the symptoms of tardive dyskinesia may occur through a mechanism which does not necessarily link transmission involving both dopamine and GABA.

Animals↗
PubMed1984

67Ga accumulation and heparan sulfate metabolism in lysosomes.

67Ga incorporation in the mitochondrial-lysosomal (Mt-Ly) fraction of rat liver increased sharply from 1 to 24 h after 67Ga IV injection, whereas that in the 105,000 g supernatant fraction decreased sharply from 6 to 48 h. Further, when 14C-labeled heparan sulfate (HS: biosynthesized by injection of [1-14C] glucosamine into a rat) was injected intravenously into a rat treated with Triton WR-1339, and the liver was isolated and fractionated, the radioactivity of 14C was concentrated in the lysosomal fraction. The effect of HS on 67Ga uptake in normal rat liver was also studied. On administration of 67Ga-HS complex, the peak uptake of administered radioactivity of 67Ga in rat liver occurred sooner than after the injection of 67Ga alone. The change was greatest in the Mt-Ly fraction among the subcellular fractions. Moreover, the 67Ga uptake in rat liver increased with increasing doses of HS. These results suggest that administered 67Ga may be bound to HS and that the concentration of 67Ga in lysosomes may be related to the in vivo metabolism of HS.

Absorption↗