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Biomedical subjects

N Miyata

Publications and source records attributed to N Miyata.

At least 91 records · Page 5Linked to original sources
PubMed1995

Initiating activity of quinones in the two-stage transformation of BALB/3T3 cells.

2-tert-Butyl-1,4-benzoquinone (BQ), a metabolite of the rodent carcinogen 3-tert-butyl-4-hydroxyanisole (3-BHA), has been shown previously to have initiating activity for cell transformation. In this paper, we examined the initiating activity of quinones in a two-stage transformation assay using BALB/3T3 cells. Cells were treated first with a quinone and then with the tumor promoter 12-O-tetra-decanoylphorbol-13-acetate (TPA). The quinones tested were 1,4-benzoquinone (pQ), phenyl-1,4-benzoquinone (PhQ), menadione and 2,5-di-tert-butyl-1,4-benzoquinone (DBQ) in addition to BQ. pQ is a metabolite of benzene and phenacetin, and PhQ is a metabolite of o-phenylphenol (OPP) and sodium o-phenylphenate (OPP-Na). All of the tested quinones induced transformation in the presence of TPA but not in its absence. The extent of transformation caused by quinones followed by TPA was weak but statistically significant. Thus these quinones were shown to act as initiators in the transformation of BALB/3T3 cells. This result suggests that BQ, pQ and PhQ may be involved in carcinogenesis by 3-BHA, benzene, phenacetin, OPP and OPP-Na in vivo. Menadione has been reported to cause cytotoxic effects and mutations through active oxygen generation from semiquinone radicals. DBQ has two bulky substitutes which interfere with covalent bonds with DNA. Menadione and DBQ exhibited initiating activity in the present study. This result suggests that active oxygens generated from semiquinone radicals may play a role in the initiation of cell transformation.

3T3 Cells↗
PubMed1995

Increased number of circulating HTLV-1 infected cells in peripheral blood mononuclear cells of HTLV-1 uveitis patients: a quantitative polymerase chain reaction study.

AIMS: This study aimed to characterise the status of viral infection in patients with HTLV-1 uveitis (HU) by quantifying the circulating HTLV-1 infected cells in the peripheral blood. METHODS: Genomic DNA samples of peripheral blood mononuclear cells (PBMC) were obtained from 25 patients with HU, 14 patients with tropical spastic paraparesis/HTLV-1 associated myelopathy (TSP/HAM), and 21 asymptomatic carriers of HTLV-1. Quantitative polymerase chain reaction (PCR) of the gag region of HTLV-1 provirus DNA was performed on these DNA samples. To confirm the PCR, genomic Southern blot hybridisation was performed to identify integrated HTLV-1 provirus. This procedure detected a few percent of HTLV-1 infected cells in the PBMC. RESULTS: Most of the HU patients had a significantly increased number of circulating HTLV-1 infected cells (mean (SD) 3.84% (4.45%) of the PBMC), whereas the percentage of infected cells in most asymptomatic carriers was less than 1% (0.54% (1.11%)). Most of the TSP/HAM patients also had a relatively high percentage (11.63% (7.67%)). The differences among these three groups were highly significant by the Mann-Whitney U test. CONCLUSION: The results suggested that the increase in the number of HTLV-1 infected cells is one base for the development of inflammatory HU lesions, as it is for TSP/HAM.

Adult↗
PubMed1995

Insulin autoimmune syndrome after the third therapy with methimazole.

In 1986, a 26-year-old female had been diagnosed as having Graves' disease and had been treated with methimazole for four months. After the treatment with propylthiouracil for another four months, she had been treated with methimazole once again. She was in complete remission for two years. She again experienced symptoms of hyperthyroidism, and treatment with methimazole was started again. On the thirteenth day after treatment, she experienced hypoglycemic attacks with skin eruption. The plasma glucose was 57 mg/dl, 125I-Insulin binding 69%, free IRI 196 microU/ml. The patient had the HLA-DRB1*0406.

Adult↗
PubMed1995

[Calculation of surgically induced astigmatism].

We compared several mathematical methods for the calculation of surgically induced astigmatism, including Jaffe's horizontal component, Jaffe's vector, Cravy's axis-based cylinder, and Holladay's with-the-wound cylinder. Computer stimulation indicated that Jaffe's vector and Holladay's with-the-wound cylinder methods correctly calculate the surgically induced astigmatism regardless of the direction of wounds. The remaining two methods, however, were found to give erroneous values when the wound is constructed off the x-y axis. Holladay's parameter was least affected by the deviation of the surgical axis. When pre- and postsurgical data of eyes undergoing cataract surgery were analyzed (55 eyes were operated on with a 5.5 mm incision located superiorly, 35 eyes with a 5.5 mm incision located supratemporally, and 40 eyes with a superiorly located 3.2 mm incision), only the Holladay's with-the-wound cylinder method could calculate the actual amount of with-and/or against-the-wound changes.

Aged↗
PubMed1995

[19F-MR imaging of transplanted tumor: perfluorochemicals as a fluorine tumor imaging agent].

PURPOSE: The purpose of our study was to detect tumor selectively using 19F-magnetic resonance imaging (MRI) and to assess Fluosol-DA, a perfluorochemical emulsion, as a tumor imaging agent for 19F-MRI. MATERIALS AND METHODS: SCC VII cells were transplanted in the right leg of mice. After 6 days, Fluosol-DA was administrated intravenously (40 ml/kg). 19F-MR imaging was performed on a Bruker CSI Omega 2 at 4.7 Tesla using a homemade volume coil. RESULTS: In vitro, the concentration and 19F signal intensity of FDA showed a very high correlation (r = 0.9997). Detection on MRI was possible at a concentration of 2%. In vivo, images of 19F in SCC VII tumors were achieved in animals 2 days after the administration of FDA. CONCLUSION: Our study confirms the feasibility of 19F-MR in vivo imaging of tumors using the fluorine compound FDA.

Animals↗
PubMed1995

[Primary trabeculectomy for open-angle glaucoma with mitomycin C].

We examined the results of postoperative intraocular pressure (IOP) control and complications of trabeculectomy with mitomycin C in open angle glaucoma patients who had not undergone any other ocular surgery. The subjects were 80 eyes of 70 patients who underwent surgery with 0.04% mitomycin C as an adjunct for 3 minutes and were followed for 7-24 months (mean +/- standard deviation: 13 +/- 3.4). The preoperative IOP was 21-32 mmHg (mean +/- standard deviation: 24.6 +/- 4.3) in maximum tolerable medications. IOP control ratio, which was analysed with the Kaplan-Meier method at 24 months after surgery was 81.6% without any antiglaucoma medications, vs 92.0% with medications. These values were significantly higher (p < 0.05) than the results of trabeculectomy with 5-fluorouracil or without antimetabolic agents previously performed in our clinic. Shallow chamber in 18 eyes (23%), choroidal detachment in 14 eyes (18%), hypotonus maculopathy in 7 eyes (9%), and cataract progression in 5 eyes (7%) were recognised as complications. Although there are some complications to be conquered, trabeculectomy with mitomycin C seems to be effective in treating primary open angle glaucoma patients.

Adult↗
PubMed1994

[Thermotolerance and heat shock protein (HSP 70) in vascular endothelial cells].

Recently, it was determined that the endothelial cells of blood vessel play a very important physiological role in the regulation of blood coagulation and selective permeability. To study the thermotolerance of vascular endothelial cells, human umbilical vein endothelial cells (HUVEC) were heated at 40, 43, 45 or 50 degrees C for various lengths of time with or without preheating at 40 or 43 degrees C for 30 min. The cell viability (CV) of HUVEC decreased gradually according to heating time. However, the CV of preheated HUVEC decreased slightly or not at all. Heat shock protein (HSP) in HUVEC heated at 37, 40, 43, or 45 degrees C was examined by immunoblotting. A new HSP 70 band was detected in HUVEC by heating at 40, 43 or 45 degrees C. HUVEC revealed thermotolerance with induction of HSP by heat stress.

Cell Survival↗
PubMed1994

Effects of CD-832, a dihydropyridine derivative with a nitrate ester moiety on rabbit femoral artery and vein.

We investigated the effects of CD-832 ((4R)-(-)-2-(nicotinoyl-amino)ethyl 3-nitroxypropyl 1,4-dihydro-2,6-dimethyl-4,3-nitrophenyl, 3,5-pyridine dicarboxylate), a dihydropyridine derivative with a nitrate ester moiety, on contractile responses in rabbit femoral arteries and veins. CD-832 (10(-8) to 10(-6) M and nifedipine inhibited the 64 mM KCl-induced and 10(-6) M norepinephrine-induced contractions of rabbit femoral arteries, while nitro compounds had no effect on the contractions. CD-832 (10(-8) to 10(-6) M) and nitro compounds inhibited the 10(-6) M norepinephrine-induced contractions in rabbit femoral veins, while other Ca2+ channel antagonists had little effect. The inhibitory effects of CD-832 (10(-7) M) on norepinephrine-induced contractions were antagonized by treatment with methylene blue (10(-5) M). These results indicate that CD-832 potently relaxes venous smooth muscle, and that it may be a useful agent for the treatment of angina pectoris.

Animals↗
PubMed1994

Role of cyclic GMP in inhibitory effects of CD-349 in isolated blood vessels.

1. We investigated the effects of CD-349, a dihydropyridine derivative with nitrate ester, on contractile responses induced by high K+, norepinephrine (NE) and Ca2+ in isolated rabbit aorta. 2. CD-349 (10(-9)-10(-5) M) and nifedipine (10(-9)-10(-5) M) equally inhibited the 64 mM KCl-induced contraction of the aortic strips in a concentration-dependent manner. 8-Br-cyclic GMP (10(-3) M) did not inhibit the KCl-induced contraction of the aortic strips. 3. CD-349 (10(-8)-10(-5) M) and 8-Br-cyclic GMP (10(-6)-10(-3) M) inhibited the 10(-6) M NE-induced contraction of the aortic strips in a concentration-dependent manner. However, nifedipine had no effect on the NE-induced contraction in rabbit aorta. 4. The inhibitory effects of CD-349 on NE-induced contraction were antagonized by treatment with methylene blue and oxyhemoglobin, while they were augmented by treatment with zaprinast. 5. CD-349 (10(-8)-10(-5) M) and 8-Br-cyclic GMP (10(-5)-10(-4) M) inhibited the NE-induced phasic contraction and Ca(2+)-induced contraction of the aortic strips preincubated with NE in Ca(2+)-free medium. However, nifedipine (10(-5) M) had little or no effect on both NE-induced phasic contraction and Ca(2+)-induced contraction of the aortic strips preincubated with NE in Ca(2+)-free medium. 6. CD-349 (10(-7)-10(-5) M) increased the levels of cyclic GMP in rabbit aorta. 7. These results indicate that CD-349 has a hybrid property deriving from Ca(2+)-antagonist and cyclic GMP increasing agents.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1994

Multidirectional contraction of human hypertrophied prostate.

1. The purpose of the present investigation is to evaluate muscle contraction in two directions (longitudinal and circumferential to urethra) physiologically and morphologically for alpha-adrenoceptor agonists. 2. Norepinephrine (10(-7)-10(-4) M), phenylephrine (10(-7)-10(-4) M) and clonidine (10(-7)-10(-4) M) induced contractions in a dose-dependent manner on human prostate from patients with benign prostatic hypertrophy (BPH). 3. No significant differences were observed between longitudinal and circumferential directions of human prostate in 50% of the maximal muscle contraction (EC50 values) and the maximal muscle contractions caused by any agents used. 4. Morphometric analysis for muscle in prostates was performed using formalin-fixed, paraffin-embedded sections stained by the Mallory-Azan method. 5. There was no significant difference in the density of the muscle area between longitudinal and circumferential directions of prostatic strips. 6. These results suggest that there are no significant differences in responsiveness of alpha-adrenoceptor agonists and the smooth muscle contents in longitudinal and circumferential directions to urethra, for human hypertrophied prostate.

Adrenergic alpha-Agonists↗
PubMed1994

Detection of nitro-azabenzo[a]pyrene derivatives in the semivolatile phase originating from airborne particulate matter, diesel and gasoline vehicles.

Mutagens in the semivolatile phase of airborne particulate matter, diesel and gasoline engine emissions were investigated using chemical and biological assays. The previously unknown mutagens, 1-(3-)nitro-6-azabenzo[a]pyrenes (1-N-6-ABP and 3-N-6-ABP) and 1-(3-)nitro-6-azabenzo[a]pyrene-N-oxides (1-N-6-ABPO and 3-N-6-ABPO), were detected in the semivolatile phase, which was adsorbed onto XAD-4 resin combined with a Teflon-coated fibre filter. Dichloromethane extracts of materials adsorbed onto XAD-4 resin were divided into acidic, neutral and basic by liquid-liquid separation. These chemicals in the basic fraction were the major mutagens in the semivolatile phase when they were bioassayed using Salmonella typhimurium TA98 in the absence of S9 mix; the mutagenicity of the basic fraction contributed at the rate of 42.9-68.8% of that of crude extracts for airborne, diesel and gasoline emission materials. As the mutagens were found to be difficult to analyse by gas chromatography (because of their probable absorption onto the packing) they were purified by HPLC and analysed by mass spectrometry. The concentrations of 1-N-6-ABP, 3-N-6-ABP, 1-N-6-ABPO and 3-N-6-ABPO detected were 1.1, 1.2, 0.8 and 0.3 ng/g, respectively, of materials in the airborne sample, and 4.9, 7.7, 2.2 and 3.8 ng/g, respectively, of materials in the diesel emission. Only 1-N-6-ABP (3.4 ng/g) and 3-N-6-ABP (4.9 ng/g) were detected in the semivolatile phase of the gasoline engine emission.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants↗
PubMed1994

Combined paraumbilical perforator skin flap and vascularized pubic bone graft.

A severely depressed deformity of the buccal region was repaired with an osteocutaneous flap based on the deep inferior epigastric vessels. This osteocutaneous flap has not been previously described in the literature. The superior pubic ramus, supplied by pubic branches from the deep inferior epigastric vessels, forms the bony portion of the combined flap. The cutaneous portion is also supplied by the deep inferior epigastric vessels and its thickness can be adjusted. This combination is useful when requiring both a thin flap and a flat bone.

Adult↗
PubMed1994

Human T lymphotropic virus type 1 uveitis after Graves' disease.

A distinct clinical entity of uveitis associated with human T lymphotropic virus type 1 (HTLV-I) has been reported previously. During the period between January 1989 and April 1992, 93 patients were observed with HTLV-I uveitis and a significant correlation was found between Graves' disease and HTLV-I uveitis. Sixteen of the 93 patients with HTLV-I uveitis (17.2%) had a previous history of Graves' disease. Fifteen patients were female (15/60, 25.0%) and one was male (1/33, 3.0%). Interestingly, uveitis occurred after the onset of Graves' disease in all cases. On the other hand, none of 222 patients with idiopathic uveitis who were seronegative to HTLV-I had a history of Graves' disease. Although the mechanisms by which HTLV-I causes the correlation between uveitis and Graves' disease are unknown, the present data suggest that immune mediated or autoimmune mechanisms are involved in HTLV-I uveitis.

Adult↗
PubMed1994

Effects of vitamin E deficiency on hepatic microsomal cytochrome P450 and phase II enzymes in male and female rats.

The effects of a vitamin E (VE) deficient diet given for 120 days on total cytochrome P450 (P450) contents and UDP-glucuronyl transferase (UDPGT) and sulfotransferase (ST) activities were investigated in rat liver of both sexes. The VE deficient regimen lowered the serum VE levels, increasing the hepatic malondialdehyde concentration regardless of animal sex, which shows an elevation of the tissue peroxi-disability. Hepatic total P450 contents were significantly decreased in male rats given the VE deficient diet, whereas the effects on female rats were less obvious. Concerning phase II enzymes, VE deficiency had no effect on the activities of UDPGT and ST in rats of both sexes. The data suggest that overall capacity of detoxification of xenobiotics may be impaired by VE deficiency to a much greater extent in male than in female rat liver.

Animals↗
PubMed1994

Human T-lymphotropic virus type I uveitis.

In addition to adult T-cell leukemia (ATL) and chronic myelopathy (HAM/TSP), our current study indicates that human T lymphotropic virus type I (HTLV-I) is a causative agent for a specific type of uveitis with unknown etiology (idiopathic uveitis). The present paper describes the seroepidemiological, clinical, and molecular biological evidences that indicate uveitis seen in HTLV-I asymptomatic carriers (HTLV-I uveitis) is a distinct clinical entity. In an HTLV-I endemic area in Japan, the seroprevalence of HTLV-I in idiopathic uveitis was 38%, while those in uveitis with defined etiology and in non-uveitic ocular diseases were 10% and 19%, respectively. Strikingly, the HTLV-I seroprevalence in younger aged patients (20-49 years) with idiopathic uveitis was 49%, while only 8% in the control group (P < 0.001). A very similar observation was recorded even in HTLV-I less endemic area, suggesting that HTLV-I infection plays a role as a risk factor for idiopathic uveitis. Clinical analysis revealed that an intermediate uveitis characterized by moderate opacities in the vitreous body and retinal vasculitis was seen in the majority the patients. The proviral DNA of HTLV-I was detected from inflammatory cells in the eye of all tested patients using PCR technique. These data thus indicate that HTLV-I is closely related to a certain type of uveitis and the uveitis (HTLV-I uveitis) is a distinct clinical entity.

Adolescent↗
PubMed1993

CD-832, a new dihydropyridine derivative with both nitrate-like and Ca2+ channel antagonist vasodilator activities.

We investigated the effects of CD-832 ((4R)-(-)-2-(nicotinoylamino)ethyl 3-nitroxypropyl 1,4-dihydro-2,6-dimethyl-4,3-nitrophenyl, 3,5-pyridine dicarboxylate), a new dihydropyridine derivative with nitrate ester, on contraction and relaxation responses induced by various vasoactive agents in rabbit aorta. CD-832 potently inhibited the specific binding of [3H](+)-PN200-110 to rat brain membranes. The IC50 values for [3](+)-PN200-110 binding were 2.8 nM and 4.9 nM in CD-832 and nifedipine, respectively. CD-832 (10(-8) to 10(-5) M), diltiazem (10(-8) to 10(-5) M) and benidipine (10(-8) to 10(-5) M) inhibited the 64 mM KCl-induced contraction of the aortic strips in a concentration-dependent manner. Neither nitroglycerin (10(-8) to 10(-5) M) nor nicorandil (10(-8) to 10(-5) M) affected the 64 mM KCl-induced contraction in rabbit aorta. CD-832 (10(-8) to 10(-5) M), nitroglycerin (10(-8) to 10(-5) M) and nicorandil (10(-5) M) had no effect on norepinephrine-induced contraction in rabbit aorta. Nitroglycerin (10(-5) M), atrial natriuretic peptide (10(-8) M), nicorandil (10(-5) M) and CD-832 (10(-7) to 10(-5) M) augmented the isoproterenol-induced relaxation responses of rabbit aorta precontracted with endothelin-1 (1 x 10(-7) to 2 x 10(-7) M). The effects of nitroglycerin (10(-5) M), nicorandil (10(-5) M) and CD-832 (10(-5) M) on isoproterenol-induced relaxation responses were antagonized by treatment with methylene blue (10(-5) M) and oxyhemoglobin (10(-5) M).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Clinical and immunologic features of human T-cell lymphotropic virus type I uveitis.

The clinical features of idiopathic uveitis were compared by the seropositivity for human T-cell lymphotropic virus type I. The statistical analysis of various clinical variables disclosed that the uveitis seen in seropositive patients (93 patients) had a significantly higher incidence of floaters, vitreous opacities, retinal vasculitis, and intermediate uveitis than that in seronegative patients (222 patients) (P < .05). The odds ratios of the virus infection for these clinical manifestations were high and statistically significant, suggesting that the virus infection has a role as a risk factor for the development of these clinical manifestations. Although visual acuity at the initial examination was almost equal between the two groups, after the therapy with topical or systemic corticosteroids, or both, visual acuity in seropositive patients was much better than that in seronegative patients. The surface phenotype of peripheral lymphocytes in the two groups was compared as follows: CD4-positive T lymphocytes (P < .05), CD4/8 ratio (P < .01), and CD25-positive T lymphocytes (P < .05) were significantly higher in seropositive patients than in seronegative patients.

Adult↗