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Biomedical subjects

Y Miyata

Publications and source records attributed to Y Miyata.

At least 289 records · Page 16Linked to original sources
PubMed1985

Short-term screening of promoters of bladder carcinogenesis in N-butyl-N-(4-hydroxybutyl)nitrosamine-initiated, unilaterally ureter-ligated rats.

The modifying effects of 17 environmental chemicals on the development of lesions in the urinary bladder of rats with unilateral ureteric ligation were investigated. Lesions were initiated by treatment of the animals with 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) for 2 weeks, and then test chemicals were given for 22 weeks. The lesions of the urinary bladder found were preneoplastic papillary or nodular hyperplasias (PN hyperplasias) and papillomas. Additions of sodium saccharin (5%), sodium o-phenylphenate (2%), butylated hydroxyanisole (2%), and sodium L-ascorbate (5%) to the diet had significant promoting effects on the incidences and numbers of PN hyperplasias and papillomas per 10 cm of basement membrane of the urinary bladder in this system. Sodium erythorbate (5%), ethoxyquin (0.8%) and carbazole (0.6%) significantly increased the incidence of PN hyperplasias. N-Nitrosopyrrolidine (0.02%) did not affect the incidence or number of PN hyperplasias but increased those of papillomas. Sodium o-phenylphenate also induced PN hyperplasias in rats without BBN-initiation. Ascorbic acid, ascorbic stearate, three dihydroxyphenols, methylhydroquinone, pyrogallol, quinoline, and uric acid did not show promoting activity in this test system. Thus, 8 of 17 chemicals tested had various promoting effects on urinary bladder carcinogenesis. These results show that this test system of BBN-initiated, unilaterally ureter-ligated rats should be useful for the detection of new bladder carcinogens and promoters.

Animals↗
PubMed1984

Cardiovascular changes in the terminal stage of disease.

In 11 patients with brain death, we measured cardiovascular parameters until cardiac arrest. After withdrawal of vasopressors, we observed marked falls in the cardiac output, systemic vascular resistance, heart rate and arterial pressure. In consequence, there was a marked decrease in oxygen delivery and the fall in arterial pressure established a vicious circle and circulatory death ensued. Most pronounced changes were left heart dysfunction and a fall in systemic vascular resistance. On the other hand, depression of the right side of the heart was half of that of left side, and the pulmonary circulation and volume status were well maintained until death. At the same time we found in these patients that body temperature and organ function except that of the brain were well maintained in brain dead patients. For resuscitation of apparently dead patients one must maintain not only cardiac functions but also systemic vascular functions.

Adult↗
PubMed1984

Promoting effects of unilateral ureteric ligation on two-stage urinary bladder carcinogenesis in rats.

The effect of ligation of the left ureter on the development of lesions in the urinary bladder were investigated in male F344 rats treated with 0.05% N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) for 2 weeks followed by 0.002% N-ethyl-N-(4-hydroxybutyl)nitrosamine (EHBN) for 10 or 22 weeks. The lesions of the urinary bladder found in weeks 12 and 24 in rats treated with BBN and EHBN were preneoplastic papillary or nodular hyperplasia (PN hyperplasia), papilloma and cancer. The incidences and numbers of these lesions per 10 cm of basement membrane of urinary bladder were increased significantly by ureteric ligation. Treatment with BBN or EHBN only induced no remarkable change and thus the doses used were subcarcinogenic in the conditions used. The results show that unilateral ureteric ligation enhanced two-stage bladder carcinogenesis.

Animals↗
PubMed1984

Development and growth of extensor carpi radialis longus muscle in normal and dystrophic chickens.

The development and growth of the skeletal muscles in normal and dystrophic chickens were studied to obtain a clue to the mechanism of dystrophic pathogenesis. A relatively small and isolated muscle--the extensor carpi radialis longus (ECRL) muscle--was utilized to analyze quantitatively the histologic and physiologic parameters. Both normal and dystrophic chickens attained qualitatively the same parameters, but there were some quantitative differences. The first disorder to appear in the dystrophic muscle was a substantial retardation of muscle cell proliferation in the early postnatal development, and the fiber loss was fully compensated by hypertrophy of the remaining cells. The succeeding abnormalities in the dystrophic muscle, e.g., reduction of efficiency in the tension output per unit area, were interpreted as compensating reactions. Therefore, it is likely that the dystrophic lesions in avian muscular dystrophy are caused by retardation of muscle cell proliferation in the early postnatal period. Possible mechanisms for the retardation are discussed in terms of the nerve--muscle trophic interactions which could be greatly intensified in the early postnatal period.

Animals↗
PubMed1984

Transplantation of extensor carpi radialis longus muscle in normal and dystrophic chicks.

The etiology of avian muscular dystrophy was examined by a cross-transplantation technique. Care was taken for the transplants to regenerate and develop under neural influence, by using the small extensor carpi radialis longus (ECRL) muscle. The ECRL muscles were exchanged between normal and dystrophic chicks 2 to 3 days ex ovo, and the muscle weight, number of muscle fibers, muscle fiber size, and contractile properties of the transplanted muscles were observed 60 to 65 days after operation when the tissue reconstitution was virtually complete. The results obtained for the physiologic, anatomic, and histologic parameters strongly suggested that there exists some failure in the host environment of the dystrophic chicken. The analyses of the histologic parameters suggested that a genetic disorder may also reside in the muscle tissue itself. The myotonic nature of the muscle membrane, however, probably does not contribute significantly to the abnormal behavior of dystrophic chickens. The importance of some neurogenic abnormalities in avian muscular dystrophy is discussed in relation to the results reported by other investigators.

Action Potentials↗
PubMed1984

The influence of histologic type on survival in early extranodal non-Hodgkin's lymphoma in head and neck.

Since the Rappaport classification provides little information for the prognosis of extranodal non-Hodgkin's lymphoma (NHL), the Kiel classification was used for 71 patients with head and neck extranodal NHL, stages IE and IIE. The ratios of low grade malignancy ( LGM ) and high grade malignancy ( HGM ) were about 60 and 40%, respectively. The lesions comprised 37 non-thyroid lymphomas and 34 thyroid lymphomas. 8 cases of thyroid NHL did not fit into a rigid classification scheme, and were separatively analyzed. In the whole group of patients and the subset of 37 patients with non-thyroid NHL, the 5-year survival rates for LGM were significantly better than for HGM . LGM showed a more favorable prognosis than HGM in 26 patients with thyroid NHL, but the difference was not statistically significant. 8 cases of thyroid NHL showed diffuse proliferation of centrocytes or centroblasts in which various numbers of nodules consisting of large centroblasts and centrocytes with high mitotic activity were scattered. The cases behaved as HGM . From these findings, we suggest that the Kiel classification in extranodal NHL is helpful.

Adolescent↗
PubMed1984

Developmental changes in serum ferritin concentration of dairy calves.

Serum ferritin concentration of nursing calves was measured by a two-site immunoradiometric assay to assess developmental changes and to evaluate relationships of serum ferritin with iron-related blood characteristics. Serum ferritin concentration of calves was low at birth and elevated slightly at 3 days of age. From 1 wk of age onward, serum ferritin concentration of untreated calves and calves fed only whole milk for 4 wk decreased and remained low throughout the nursing period. This finding almost coincided with hematological characteristics. However, that nearly normal hematological measures and weight gain persisted and that they did not develop any anemic symptom indicate that serum ferritin concentration is more sensitive than other hematological characteristics to iron depletion. However, serum ferritin concentration of calves administered 130 mg of ferrous fumarate (40 mg iron) daily from 3 to 22 days of age or injected with 4 ml of iron-dextran intramuscularly (400 mg iron) at 3 days and 2 wk of age increased sharply just after treatment and persisted high for 2 to 6 wk of age. However, there was large variation between animals for serum ferritin concentration. Thus, it seems likely that serum ferritin concentration is an index for monitoring prelatent iron deficiency of calves.

Administration, Oral↗
PubMed1984

Effects of 12-O-tetradecanoylphorbol-13-acetate on carcinogenesis in the heterotopically transplanted rat urinary bladder.

12-O-Tetradecanoylphorbol-13-acetate (TPA), a potent promoter of mouse skin carcinogenesis, was tested for possible tumor-enhancing effects on urinary bladder carcinogenesis using the heterotopically transplanted bladder (HTB) model. Weekly administration of TPA at 1.0 microgram/week to N-methyl-N-nitrosourea-initiated HTBs did not increase tumor incidence, but instead, resulted in a significantly high incidence of nodulopapillary hyperplasia, an early neoplastic lesion, suggesting possible tumor enhancement by TPA. In addition, administration of a high dose of TPA with or without a carcinogen treatment led to the development of numerous finger-like epithelial projections on the luminal surface of the HTBs. Evidence indicates that epithelial projections are formed as a result of proliferation of intermediate cells. Whether these structures evolve into true neoplastic lesions is at present unknown.

Animals↗
PubMed1983

Screening for carcinogens by DNA-synthesis inhibition test using mouse L-cells.

Bacterial test systems for potential carcinogens sometimes give false negative results. To overcome this problem, several short term test systems have been described. One of them is the DNA-synthesis inhibition test described by Painter (1977). Our DNA-synthesis inhibition test system using mouse L-cells gave positive results when monocrothaline, phenacetin and thioacetamide, which were negative in the Ames test, were tested.

Animals↗
PubMed1983

A new mutant mouse with motor neuron disease.

The present study was undertaken to examine the abnormality in motor function of newly found mutant mice electrophysiologically. It was found that their motor nerve fibers progressively fail to conduct action potentials, while impulse conduction in the sensory fibers remains intact. The conduction block of motor fibers proceeded in the proximo-distal direction. Excitation of the motor fibers was blocked by raising the extracellular Ca2+ or Mg2+ concentration in vitro. It is concluded that this new mutant mouse has a motor neuron disease of the 'dying-forward' type.

Animals↗
PubMed1983

Changes in the distribution of the extrajunctional acetylcholine sensitivity along muscle fibers during development and following cordotomy in the rat.

Acetylcholine sensitivity along the entire length of muscle fibers was studied during postnatal development and following transection of the spinal cord in the rat. During postnatal development, the acetylcholine sensitivity in the soleus and extensor digitorum longus muscles decreased faster at the juxtajunctional region than near the tendons. Thus, the adult pattern of low acetylcholine sensitivity at the extrajunctional membrane was achieved through the uneven change of acetylcholine sensitivity during normal development. This uneven pattern of the sensitivity was found to appear in both muscles in older rats after cordotomy, and is in striking contrast to the uniform pattern in denervated muscles. The uneven appearance of the sensitivity could not be explained by changes in input resistance or resting membrane potential. In the soleus muscle whose nerve was implanted at an ectopic site, the lowest sensitivity also appeared at the ectopic juxtajunctional region after cordotomy. These results indicate that the motor nerve exerts regionally different effects along a fiber with respect to the appearance of acetylcholine receptors.

Acetylcholine↗
PubMed1983

Treatment of carcinoma of the uterine cervix by remotely controlled afterloading intracavitary radiotherapy with high-dose rate: a comparative study with a low-dose rate system.

From September, 1974 through December, 1979, a total of 249 patients with carcinoma of the cervix uteri Stage IIb and III were randomly allocated to either remotely controlled high-dose-rate intracavitary radiotherapy or manual afterloading low-dose-rate therapy, with radiotherapy of 20 Gy in 2 weeks to Point A to whole pelvis and 40 Gy in 4 weeks to the parametria. The dose to Point A by intracavitary radiotherapy was 40-60 Gy with one or two fractions in the low-dose-rate group and 30 Gy for the high-dose-rate group by 3 fractions with a once a week schedule. The purpose of this paper is to compare the results between the groups and to clarify the problems in the high-dose-rate group clinically. The local control rate was higher in the high-dose-rate group; however, the complication rate was also higher in this group than in the low-dose-rate group. The dose schedule and the place of rectal dose measurement is discussed. The overall cumulative survival rate was nearly the same in both groups (55% at 5 years), although some difference was noted in each stage. The most common cause of death was distant metastasis outside the pelvis and the second most common was intercurrent disease in Stage IIb and local failure in Stage III.

Brachytherapy↗