Search PubMed⌕ Search

Biomedical subjects

T Miyazaki

Publications and source records attributed to T Miyazaki.

At least 505 records · Page 28Linked to original sources
PubMed1993

[Partition behavior of tropane alkaloids between organic solvents and water].

The partition behavior of tropane alkaloids (TrA) between organic solvent and water was studied under various conditions. The apparent partition coefficient, log P', increases with pH with a slope of +1 in the acidic to neutral pH range, then tends to approach to a constant value in the alkaline region. Thus the partition of TrA to the organic phase is based on the neutral form of TrA. From the pH dependency of the partition and pH titration of TrA, the intrinsic partition coefficients log P0 and pKa values for each TrA were estimated. Values of pKa and log P0 for scopolamine were smaller than those for atropine or homatropine. It was considered that the presence of the epoxide ring in scopolamine molecule reduces the log P0 and pKa because of its polar and electro-inductive effect. It was also expected from the results of pH-dependent partition behavior that in the low pH region some portion of TrA cations is transferred to the organic phase by forming an ion-pair complex with an anion, in the aqueous phase. The log P' of TrA was measured in the presence of various kinds of anions (halides and alkyl sulfonates, C5-C8) at about pH 2, where almost all TrA are present as a protonated form. The relations between the log P' and the logarithmic concentration of anions is linear at low concentrations of anions as expected from the ion-pair partition equation.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaloids↗
PubMed1993

[Effect of carperitide (alpha-human atrial natriuretic polypeptide) on the cardiovascular system in experimental animals].

The cardiovascular and diuretic actions of carperitide were studied in experimental animals. Carperitide relaxed various canine arteries and veins that were contracted by high K+ or norepinephrine. Carperitide stimulated particulate guanylate cyclase from rat thoracic aortas. Carperitide had almost no effect on coronary perfusion pressure or heart rate, but caused a slight decrease in contractile force in isolated guinea pig hearts. Carperitide tended to decrease isoproterenol-induced renin release from isolated rat kidney slices and elicited decreases in angiotensin II-induced aldosterone release from bovine zona glomerulosa cells. Intravenous injection of carperitide elicited decreases in arterial blood pressure and total peripheral resistance in the anesthetized and conscious dogs. Carperitide also elicited transient increases in cardiac output and coronary blood flow followed by slight decreases in them. Intravenous infusion of carperitide elicited decreases in pulmonary capillary wedge pressure, pulmonary pressure and right atrial pressure in association with elevating plasma carperitide (ANP like immuno-reactivity) level in dogs with heart failure induced by coronary artery occlusion and saline loading. These results suggest that carperitide decreases both preload and afterload and can improve the untoward hemodynamic alterations in animals with acute experimental heart failure.

Animals↗
PubMed1993

Preparation of a photoaffinity probe for the Man6P/IGF-II receptor.

A photoaffinity probe, 2-(4-phosphopentamanniminophenyl)ethyl-(4-azido) salicylamide, was prepared for photolabelling of the mannose 6-phosphate/insulin-like growth factor II receptor. The probe was synthesized from phosphopentamannan and 2-(4-aminophenyl)ethylamine followed by coupling with photosensitive 4-azidosalicylic acid. The 125I-labelled probe was reacted with receptor purified from rat liver under irradiation with ultraviolet light. Fluorography of the reaction product on a polyacrylamide gel effectively detected the receptor coupled to the photoprobe as a molecular mass of 250 kDa. Specific binding of the probe or of radiolabelled insulin-like growth factor II was not inhibited by the growth factor or by mannose 6-phosphate, confirming different binding sites to the receptor between the ligands.

Affinity Labels↗
PubMed1993

Two cases of lung carcinoma with osteoplastic bone metastasis.

Two cases of lung carcinoma with osteoplastic bone metastasis are reported. The bone roentgenogram of a 66-year-old woman with pleuritis carcinomatosa revealed multiple sclerotic changes in the right forearm, lumbar spine, and pelvis. Biopsy at internal fixation of the left humerus revealed metastatic adenocarcinoma with osteoplastic change. In a 77-year-old man with small cell carcinoma of the lung, after chemotherapy, osteoplastic bone changes were detected in roentgenograms. An ivory vertebra formation was seen in L1, L2 and L4, and bone scintigram showed, additionally, uptake in the ilium.

Adenocarcinoma↗
PubMed1993

Intrahepatic cholangiocarcinoma: spin-echo and contrast-enhanced dynamic MR imaging.

OBJECTIVE: Our purpose was to identify the conventional spin-echo and contrast-enhanced dynamic MR imaging features of intrahepatic cholangiocarcinoma. MATERIALS AND METHODS: Eight patients with pathologically proved intrahepatic cholangiocarcinoma were examined with conventional spin-echo and contrast-enhanced dynamic MR imaging with a 1.5-T superconductive unit. The results were analyzed to include the signal intensity of the mass relative to liver parenchyma on conventional spin-echo images and the pattern and degree of enhancement on dynamic MR images. RESULTS: The characteristic appearance of intrahepatic cholangiocarcinoma was a large mass with an irregular margin, satellite nodules, and a central scar. Tumors were hypointense relative to liver parenchyma on T1-weighted spin-echo images and hyperintense on T2-weighted spin-echo images. On dynamic MR studies, tumors characteristically had minimal or moderate rim enhancement with progressive and concentric filling with contrast material. CONCLUSION: Our study suggests that intrahepatic cholangiocarcinoma has a typical pattern on contrast-enhanced dynamic MR images.

Adenoma, Bile Duct↗
PubMed1993

BCR/ABL oncoprotein-targeted antitumor activity of antisense oligodeoxynucleotides complementary to bcr/abl mRNA and herbimycin A, an antagonist of protein tyrosine kinase: inhibitory effects on in vitro growth of Ph1-positive leukemia cells and BCR/ABL oncoprotein-associated transformed cells.

We investigated whether antisense oligodeoxynucleotides complementary to bcr/abl mRNA or protein kinase antagonists display antitumor activity on Ph1-positive leukemia cell lines. bcr/abl antisense oligomers showed inhibitory effects on the in vitro growth of Ph1-positive leukemia cell lines in liquid culture, and further displayed an inhibitory effect on transformed murine hematopoietic cells using transfection with a retroviral vector expressing P210bcr/abl oncoprotein. However, in vitro treatment with a bcr/abl antisense oligomer did not completely abolish the expression of bcr/abl mRNA and did not display the desired "killing effect" on Ph1-positive leukemia cells. On the other hand, investigation of the effect on Ph1-positive leukemia cells by various types of protein kinase antagonists revealed that herbimycin A, a protein tyrosine kinase antagonist, displays preferential and remarkable suppression of the growth of Ph1-positive leukemia cells and P210bcr/abl associated transformed cells by virtue of suppressing bcr/abl protein tyrosine kinase activity. These results may provide important future insights in developing a new category of antitumor therapy by targeting oncogene products.

Antibiotics, Antineoplastic↗
PubMed1993

[Alterations of hemostatic markers in elderly patient with atrial fibrillation without a history of stroke].

To evaluate whether hemostatic abnormalities contribute to the increased risk of stroke, the authors prospectively studied the hemostatic markers (HM) (beta-TG, PF4, FPA, TAT, PIC, D-dimer) in 34 elderly patients with atrial fibrillation (Af) without a history of stroke (mean age 79.2) and 14 age-matched controls. In the Af group FPA was significantly higher than in the control group (p < 0.05). Among them, 8 patients showed a similar abnormal HM pattern as in cardioembolic is chemic stroke and in these, 4/8 patients had valvular disease (VD), 2/8 had hypertension (HT), 2/8 had congestive heart failure (CHF), 1/8 had diabetes mellitus (DM) and 1/8 had hyperlipidemia (HL). Eight patients showed the same abnormal HM pattern as atherothrombotic is chemic stroke and of these, 2/8 had HT as complications. Five patients showed combination of a HM abnormal pattern, that was observed in cardioembolic and atherothromboic ischemic stroke. The other 13 patients showed a normal HM pattern, were in these patients, 4/13 had HT, 1/13 had DM, 1/13 had VD, and 1/13 had CHF. The patients with VD complication tended to have embolic HM abnormality. Contrary to previous reports, nonvalvular Af patients do not necessarily tend to have high risk of cardioembolic stroke. Our data suggest difficulties in clinical diagnosis among Af patients with ischemic stroke whether it is cardio embolic or atherothrombotic.

Aged↗
PubMed1993

[Observation of calcification of thyroid tumors determined by CR and CT].

Detection of calcification of the thyroid gland is very useful for the clinical diagnosis and therapy of thyroid cancer. In this study, we evaluated the usefulness of FCR (Fuji computed radiography) and CT by analyzing the correlation between the imaging findings of calcification and histological diagnosis. Fifty-one cases of follicular adenoma and 63 cases of differentiated carcinoma underwent FCR and CT. All cases undergoing operation received histological examination. Calcification was detected in 19.6% of follicular adenomas and in 46.0% of differentiated carcinomas by FCR, and 37.3% of follicular adenomas and in 63.5% of differentiated carcinomas by CT. Among cases without calcification on FCR, CT detected calcification in 26.7%. These differences between the results of FCR and CT were found in cases with small calcifications, low thyroid gland position and in whom differentiation between tracheal cartilage calcification and thyroid carcinoma calcification was difficult. In these cases, calcification was difficult to detect by FCR alone. Patients with follicular adenoma aged > or = 60 years showed a higher prevalence of calcification than younger patients. In cases of differentiated carcinoma, no relationship was seen between age and the prevalence of calcification. The classification of calcification shape by FCR showed that the majority of psammoma bodies, as well as sharp and irregular shapes, were found in differentiated carcinoma while round calcifications were found in follicular adenomas. On CT, calcification inside the tumor was found in 73.7% of follicular adenomas and in 92.5% of differentiated carcinomas. FCR and CT are more useful for the detection of calcification than conventional radiography and are of great value in screening for thyroid tumors.

Adolescent↗
PubMed1993

Effect of an ultraviolet light-activated coating material on reduction of the leaching of methyl methacrylate and formaldehyde from denture acrylic resins.

Effect of glazing with an ultraviolet light-activated coating material on reduction of the leaching of methyl methacrylate and formaldehyde from denture acrylic resins was quantitatively evaluated. Disks prepared from auto-polymerized resins were painted with the material and radiated with ultraviolet light. The disks were immersed in artificial saliva and the concentrations of methyl methacrylate and formaldehyde leached were determined by high-performance liquid chromatography and flow injection analysis. Compared to untreated controls, the glaze significantly decreased concentrations of both leachable substances. Treatment with an ultraviolet light-activated coating material is effective in suppressing the leaching of methyl methacrylate and formaldehyde from acrylic resins as well as in smoothing the denture surfaces.

Acrylic Resins↗
PubMed1993

Development of fabrication system of prostheses using electric discharge machining.

This paper outlines the principles and uses of electric discharge machining (EDM) in the fabrication of prostheses. The three areas of use of EDM are classified as supplementary use, direct fabrication of crowns and bridges and fabrication of titanium copings using a CAD/CAM process. The problems associated with the use of EDM in each area are discussed and the methods employed to overcome these problems are described. The application of numerically controlled (NC) EDM to prosthodontic work is found to be promising. Further refinement and development are necessary before EDM can be widely accepted as a means of fabricating prostheses.

Computer-Aided Design↗
PubMed1993

[Pulmonary cryptococcosis treated by combination therapy of fluconazole plus flucytosine].

The efficacy of the combination therapy of fluconazole plus flucytosine against pulmonary cryptococcosis was investigated. The minimal inhibitory concentrations of antifungal agents were measured by growth inhibition on Yeast-morphology agar plates, and the fractional inhibitory concentration index of each antifungal combination were calculated by checker-board titration. Eight of Cryptococcus neoformans clinical isolates showed sensitivity for AMPH, 5-FC, MCZ and ITZ. C. neoformans showed resistance against FLCZ. The combination of FLCZ plus 5-FC showed synergistic effect against C. neoformans. Three cases of pulmonary cryptococcosis were treated by combination therapy of fluconazole plus flucytosine. After treatment, C. neoformans isolates were eradicated and the chest X-ray improved remarkably. The combination therapy of fluconazole plus flucytosine was effective for the treatment of pulmonary cryptococcosis.

Aged↗
PubMed1993

[AIDS and opportunistic virus infections].

The opportunistic herpesvirus infections in AIDS are often life-threatening and the patients have lowered Epstein-Barr virus (EBV)-specific T cell cytotoxicity. On the other hand, the asymptomatic human immunodeficiency virus (HIV) carriers have potentially lowered EBV-specific cytotoxic T cell function, which is shown by exposure of the lymphocytes to an immunosuppressive substance. The EBV-specific T cell cytotoxicity may therefore tell the timing to cope with such opportunistic viral infections.

AIDS-Related Opportunistic Infections↗
PubMed1993

[Effects of rHuEPO on aplastic anemia: results of a phase II clinical study].

The safety and efficacy of recombinant human erythropoietin (epoetin alpha) were investigated in adult aplastic anemia patients whose hemoglobin (Hb) concentration was less than 10g/dl. Epoetin alpha was given subcutaneously every day at a dose of 3,000IU/body for two weeks, and the dosage was increased to 6,000IU, 12,000IU and 24,000IU every two weeks when the increment of Hb was insufficient. In cases in whom Hb concentration increased by more than 1g/dl or whose transfusion requirements reduced to less than 50%, treatment was judged to be effective. The whole rate of efficacy was 34.5% (10/29). Response to epoetin alpha treatment was better in patients whose symptoms were relatively mild. Mild cases responded to the treatment with 6,000IU/body/day, although a dosage of 24,000IU/body/day was required in moderate or severe cases. Neither serious adverse effect nor abnormal laboratory findings were observed. These results suggest that high dose subcutaneous epoetin alpha treatment is effective for the aplastic anemia in terms of increasing Hb concentration and reducing blood transfusions.

Adolescent↗
PubMed1993

[Effects of sevoflurane on spinal dorsal horn WDR neuronal activity in cats].

The effects of sevoflurane (S) (0.5%, 1.5%, and 2.5%) on the spinal dorsal horn wide dynamic range (WDR) neuronal activity were studied in either spinal cord intact or spinal cord transected cats. Extracellular activity was recorded in the dorsal horn from single WDR neurons responding to noxious and non-noxious stimuli applied to the cutaneous receptive fields on the left hind paw foot pads of intact or decerebrate and spinal cord transsected (L1-2) cats. When BK 10 micrograms was injected into the femoral artery ipsilateral to the recording site as the noxious test stimulus in the spinal cat, 7 of 8 WDR neurons gave excitatory responses which were not depressed by sevoflurane 0.5% and 1.5% but were depressed significantly by 2.5%. On the other hand, when BK 10 micrograms was injected into the femoral artery ipsilateral to the recording site in the intact cat, 6 of 13 WDR neurons (46%) gave excitatory responses, which were significantly depressed by sevoflurane 0.5%, 1.5% and 2.5%, and 7 of 13 WDR neurons (54%) gave inhibitory responses, which were significantly depressed sevoflurane at 0.5%, 1.5%, and 2.5%. In conclusion, we have found that sevoflurane reduces the excitation as well as the inhibition of dorsal horn WDR neuronal activity induced by BK injection.

Animals↗
PubMed1993

[A case of pulmonary aspergilloma successfully treated with combination therapy of intracavitary injection of amphotericin B and intravenous administration of urinastatin].

A 57-year-old man with pulmonary tuberculosis underwent left upper lobectomy in 1984. In 1987, chest X-ray showed a fungus ball, and Aspergillus species was isolated from sputum. He was treated by intracavitary injection of amphotericin B (AMPH) in June, 1992. However, no change was observed in the chest CT scan after a total dose of 1,000 mg of AMPH. Combination therapy of intravenous administration of 100,000 units of urinastatin and intracavitary injection of AMPH resulted in complete disappearance of the fungus ball on chest CT scan. This report describes case of pulmonary aspergilloma successfully treated with the combination of AMPH and urinastatin.

Amphotericin B↗
PubMed1993

[A case of intracranial malignant melanoma with increased uptake of IMP in SPECT].

A patient with intracranial malignant melanoma was assessed by 123I-IMP SPECT. Early image, performed 30 minutes after intravenous injection of 111 MBq 123I-IMP, demonstrated an accumulation similar to normal gray matter-defect. Delayed image, performed 4-hour after injection, demonstrated increased accumulation of 123I-IMP. 123I-IMP SPECT, especially delayed scan, was valuable for qualitative diagnosis of intracranial malignant melanoma.

Adult↗
PubMed1993

Electron spin resonance studies of free radicals in gamma-irradiated golden hamster embryo cells: radical formation at 77 and 295 K, and radioprotective effects of vitamin C at 295 K.

Formation of free radicals in golden hamster embryo (GHE) cells produced by gamma irradiation at 77 and 295 K has been studied by electron spin resonance (ESR) spectroscopy. The yields of free radicals in the gamma-irradiated frozen cells at 77 K increase linearly with increasing dose in the range from 8 Gy to 1.3 kGy, suggesting that the mechanism of radical formation at a dose of 8 Gy is the same as that at 1.3 kGy. When GHE cells are irradiated with 5 kGy gamma rays at 295 K and then the ESR spectrum is measured at 77 K, a part of the organic radicals produced can be observed clearly. The organic radicals survive in GHE cells for more than 24 h at room temperature. The formation of the organic radicals by gamma irradiation is suppressed upon the addition of vitamin C to the GHE cells. When an aqueous solution of albumin (0.1 kg dm-3) is gamma-irradiated with 5 kGy at 295 K, albumin radicals are observed by ESR. The formation of the albumin radicals is suppressed drastically upon the addition of vitamin C. The efficient radioprotection of vitamin C against radical formation has been interpreted in terms of the scavenging of albumin radicals by vitamin C.

Animals↗