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Biomedical subjects

Y Kameda

Publications and source records attributed to Y Kameda.

At least 181 records · Page 10Linked to original sources
PubMed1984

Ontogeny of chicken ultimobranchial glands studied by an immunoperoxidase method using calcitonin, somatostatin and 19S-thyroglobulin antisera.

The ontogeny of the ultimobranchial glands in chickens from 9-day-old embryos to adults was investigated by the immunoperoxidase method using anti-calcitonin, anti-somatostatin and anti-19S-thyroglobulin antisera. During embryonic development, the chick ultimobranchial glands consisted of solid cell clusters. Calcitonin immunoreactivity began to appear at 16 days of incubation and rapidly increased at late periods of incubation. At the time of hatching, almost all of the epithelial cells in the ultimobranchial glands exhibited the immunoreaction for calcitonin. Cyst structures showing various sizes, shapes and luminal contents were consistent features of the ultimobranchial glands after hatching. As age proceeded, the cysts and loose connective tissues gradually increased in the glands. In adult chickens, the calcitonin cells came to be interspersed among them and the number of the cells per unit area was very small, compared with that in young animals. No immunoreaction for somatostatin was found in the ultimobranchial glands of chickens of all ages examined. In the glands there were no cells immunoreactive to the 19S-thyroglobulin antiserum. Further, neither cyst epithelium nor luminal contents were stained with the antiserum.

Aging↗
PubMed1984

Immunocytochemical studies on differentiation of the thyroid gland in rabbit fetuses and chick embryos.

The morphogenesis of the thyroid gland in rabbit fetuses and chick embryos was investigated using the PAS stain and an immunoperoxidase method with anti-19S-thyroglobulin antiserum. In rabbit fetuses, the reaction for precursor components was firstly detected in the apical portions of follicular cells, arranged in clusters but not yet forming follicles, at 16 days of gestation. Although the first primordial follicles storing colloid droplets were observed on day 18, a drastic increase of follicle formation, the true onset of thyroid function, did not occur until day 22. The colloid in primordial follicles revealed very strong immunoreactivity for 19S-thyroglobulin. The follicles gradually increased in size with age. At 25 days of gestation the cytoplasm of follicular cells was stained densely by slightly diluted 19S-thyroglobulin antiserum, whereas the colloid was stained with highly diluted antiserum; these immunoreactions of follicular cells and colloid were comparable to those of postnatal animals. In chick embryos, significant numbers of primordial follicles were observed throughout the whole thyroid parenchyma at 9 days of incubation. On day 12, the follicles stored more PAS-positive and immunoreactive colloid. At 14 days of incubation follicles with enlarged follicular lumina, having an immunoreactivity similar to mature follicles, became increasingly common.

Animals↗
PubMed1984

Somatostatin-like immunoreactivity in mammalian thyroid glands: contents and partial characterization.

Somatostatin (SRIF)-like immunoreactivity (SLI) in the thyroid glands of human and several animal species were compared, and the SLI peptides were characterized chromatographically and immunologically. All specimens were extracted with 2 M acetic acid, and the SLI content determined by RIA. The SLI concentrations in guinea pigs [34.3 +/- (SE) 4.8 ng/mg protein] and rabbits (9.4 +/- 0.8 ng/mg protein) were much greater than those in other mammals: dogs, rats, mice, and humans. On gel filtration of extracts of the guinea pig, rabbit and dog thyroids, the major peak of SLI (1.6 K SLI) coeluted with synthetic SRIF-14 (S-14). Two other forms of SLI ("big" SLI and 3 K SLI) were also detected, although their relative proportions to total SLI were small (2.3 to 8.2%). The 3 K SLI and 1.6 K SLI from guinea pig and rabbit thyroids contained peptides coeluting with synthetic SRIF-28 (S-28) and S-14, respectively, on reverse-phase high performance liquid chromatography. The dilution curves of the two molecular forms of SLI, i.e. 3 K SLI and 1.6 K SLI, were parallel to the displacement curves of S-28 and S-14 in the SRIF RIA. It is concluded 1) that the thyroid contents of SLI varied greatly from species to species, with the highest content being found in guinea pig thyroids; 2) that in guinea pigs, rabbits, and dogs, the predominant form of thyroid SLI is 1.6 K SLI; and 3) that the 3 K SLI and 1.6 K SLI peptides from guinea pig and rabbit thyroids are immunologically and chromatographically indistinguishable from S-28 and S-14, respectively.

Animals↗
PubMed1984

Immunohistochemical study of cyst structures in chick ultimobranchial glands.

In order to clarify the functional significance of cyst structures located in ultimobranchial glands, chick ultimobranchial glands of various ages were investigated by an immunoperoxidase method using anti-calcitonin, anti-somatostatin and anti-19S-thyroglobulin antisera. At hatching, the cysts were consistent features of the chick ultimobranchial glands. With aging, they gradually increased in volume and number. In adult chickens, a major portion of ultimobranchial glands was occupied by cysts of various sizes, shapes and luminal contents. Some cyst epithelium consisted of calcitonin-positive cells alone, and a portion of the cystic contents was intensely immunoreactive to the calcitonin antiserum. Neither cyst epithelium nor luminal contents were stained with the 19S-thyroglobulin or the somatostatin antiserum. The present study indicates that some cyst structures of chick ultimobranchial glands are related to the synthesis, secretion and accumulation of calcitonin.

Age Factors↗
PubMed1984

The spontaneous loss of calcitonin and somatostatin in thyroid C cells of a guinea pig.

A guinea pig showing spontaneous abnormalities in both calcitonin and somatostatin syntheses was found. Thyroid C cells revealed an almost complete absence of secretory granules immunoreactive to calcitonin and somatostatin. Instead, vesicular inclusions of various sizes, which exhibited positive immunoreactions for calcitonin and somatostatin, were found in some C cells. There were several C cells with enlarged and eosinophil cytoplasm, showing a hyaline degeneration. The number of C cells per thyroid and their distribution pattern were not different from those of normal controls. Follicular cells did not exhibit any detectable changes, whereas parathyroid glands were somewhat degenerated.

Animals↗
PubMed1984

Valiolamine, a new alpha-glucosidase inhibiting aminocyclitol produced by Streptomyces hygroscopicus.

Valiolamine, a new aminocyclitol has been isolated from the fermentation broth of Streptomyces hygroscopicus subsp. limoneus and its structure has been determined to be (1(OH),2,4,5/1,3)-5-amino-1-C-(hydroxymethyl)-1,2,3,4-cyclohexanetetr ol. Valiolamine has more potent alpha-glucosidase inhibitory activity against porcine intestinal sucrase, maltase and isomaltase than valienamine, validamine and hydroxyvalidamine which were reported as building blocks of validamycins and microbial oligosaccharide alpha-glucosidase inhibitors. In addition, valienamine, validamine and hydroxyvalidamine have been isolated from the fermentation broth.

Chemical Phenomena↗
PubMed1984

Microbial degradation of validamycin A by Flavobacterium saccharophilum. Enzymatic cleavage of C-N linkage in validoxylamine A.

The enzymatic cleavage of C-N linkage in the degradation of validamycin A by Flavobacterium saccharophilum was examined using N-p-nitrophenyl derivatives of validamine and valienamine as synthetic model substrates for validoxylamine A. Incubation of N-p-nitrophenylvalidamine with the membrane fraction from the organism led to formation of N-p-nitrophenyl-3-ketovalidamine, and succeeding cleavage of C-N linkage. As the products of the cleavage step, one was identified as p-nitroaniline and another keto compound could not be purified enough because of its instability. However, on the basis of its hydrogenation products, the structure of the keto compound could be established as 5D-(5/6)-5-C-(hydroxy-methyl)-2,6-dihydroxy-2-cyclohexen-1-one. The same experiment was carried out with N-p-nitrophenylvalienamine. In this case, N-p-nitrophenyl-3-ketovalienamine could be isolated as an intermediate but the desired keto compound from the cleavage step could not be isolated because of its instability. The participation of two enzymes, that is, a dehydrogenase and a C-N lyase on the cleavage of C-N linkage was assured, and moreover, the analysis of its products, together with those of the previous studies allow us to propose a degradation pathway of validamycin A by Flavobacterium saccharophilum.

Flavobacterium↗
PubMed1984

Dog thyroid glands after chronic administration of antithyroid drugs.

The effect of chronic administration of antithyroid drugs on the composition of thyroid proteins in dogs was investigated. After administration of thiourea for periods of 10 days to 4 months and also of ethylenethiourea for 6 months thyroid glands were examined morphologically by immunoperoxidase staining using anti-19S-thyroglobulin and anti-albumin antisera. After follicles were devoid of apparent colloid, the immunoreactivity of follicular cells to the 19S antiserum progressively increased with administration periods. A large number of follicular cells were also densely stained with the albumin antiserum. In contrast to the immunoreaction of 19S-thyroglobulin, which was detected in all follicular cells, the appearance of immunoreactive albumin was restricted to 60-80% of the follicular cell population even after several months' administration. Thyroid extracts after treatment with ethylenethiourea for 6 months were analyzed with gel chromatography, polyacrylamide gradient gel electrophoresis, and immunoblotting. Large-molecular-weight components, including 27S iodoprotein, were completely absent in the goitrous thyroids. On the contrary, small-molecular-weight components markedly increased in number and amount, although of these two or three bands alone were weakly immunoreactive to the 19S antiserum. Both 19S and 12S components were still significant products, showing an intense immunoreactivity for 19S-thyroglobulin after the chronic administration of goitrogen. Albumin markedly increased in amount and constituted 24.2% +/- 7.6% of total stained proteins, seven times as high as the value of normal controls (3.4% +/- 2.3%).

Albumins↗
PubMed1984

Dental survey in Nigeria. Part I. Prevalence of dental caries in Nigeria.

A joint dental epidemiological survey was carried out in 1981 in the ancient city of Ile-Ife and its environs in the Federal Republic of Nigeria. The survey was made with the University of Ife, Ile-Ife, Oyo State, Nigeria, as the base. The occurrence of caries in 898 Nigerian school children of 509 urban and 389 rural children was compared with the occurrence of caries in the Japanese children. The results showed that the incidence of caries in the Nigerian school children was much lower than that of their Japanese counterpart. However, it is projected that with the increase in the consumption of sweet drinks and food in Nigeria, if superimposed on the existing poor oral hygiene, the incidence of caries will increase greatly.

Adolescent↗
PubMed1983

Distribution of C cells in monkey thyroid glands as studied by the immunoperoxidase method using anti-calcitonin and anti-C-thyroglobulin antisera.

The distribution of C cells in the thyroid glands of eight young adult monkeys (4 Macaca fuscata and 4 Macaca irus) was investigated by complete serial sections utilizing the immunoperoxidase method with anti-human calcitonin and anti-dog C-thyroglobulin antisera. The secretory granules of monkey C cells were strongly immunoreactive to both antisera. A markedly uneven distribution of C cells was found. The C cells were distributed in a small area restricted to the dorsomedial portion of the lobe along the longitudinal axis below the parathyroid IV, while the remaining larger portions were devoid of C cells. In the areas where the C cells were concentrated, the cells were scattered, surrounding a large portion or even the whole of the epithelium lining follicles and often forming multiple clusters among the follicles. In these places the C cells exceeded the number of follicular cells.

Animals↗
PubMed1983

[Neoplastic cardiac tamponade].

Pericardial metastases are frequently found and often cause cardiac tamponade which requires emergency treatment. Pericardiocentesis or subxiphoid pericardiotomy and pericardial drainage can be performed; the latter is a safe and effective method for the management of continuous pericardial effusion since it can be done under direct visualization and local anesthesia. We had four patients with neoplastic cardiac tamponade who were treated successfully with subxiphoid pericardiotomy and pericardial drainage. In three of them neoplasms had not been found until cytology of pericardial fluid proved to be malignant when they were attacked by cardiac tamponade. If the patient with malignancy is attacked by cardiac tamponade, subxiphoid pericardiotomy and pericardial drainage should be performed considering neoplastic cardiac tamponade. We have described pathophysiology, diagnosis and treatment of neoplastic cardiac tamponade.

Adult↗
PubMed1982

Immunohistochemical study of c cell follicles in dog thyroid glands.

In dog thyroid glands there are C cell follicles which are lined solely by C cells and which accumulate a colloidlike substance in the luminal cavities. In order to clarify the properties of the colloidlike substance secreted by C cells, the C cell follicles were stained with PAS reaction and immunoperoxidase method using anticalcitonin, anti-C-thyroglobulin, and anti-19S-thyroglobulin antisera, respectively. The colloidlike substance was PAS positive and revealed the strong immunoreaction for C-thyroglobulin but a faint reaction for calcitonin. It was nonreactive with anti-19-thyroglobulin antiserum. These results confirm that C cells synthesize the glycoprotein immunoreactive to anti-C-thyroglobulin antiserum in addition to calcitonin and can store it in the follicular lumens.

Animals↗
PubMed1982

Somatostatin immunoreactive C cells in thyroid glands from various mammalian species.

The relative distribution of somatostatin- and calcitonin-containing cells in thyroid glands from various mammalian species was investigated by immunoperoxidase staining, and the concentration of immunoreactive somatostatin by radioimmunoassay. In the thyroid glands of guinea pigs and rabbits, most of the calcitonin cells were also immunoreactive to the somatostatin antiserum, and high concentration of immunoreactive somatostatin was obtained. On the other hand, in the thyroids of other animal species--rats, dogs, pigs, cows, goats, cats, monkeys, mice, and hamsters--only a few C cells revealed the immunoreaction for somatostatin, and the concentration of somatostatin was low. In all animal species studied, the somatostatin was present in the same cells that contain calcitonin, though in guinea pigs and rats there were some C cells containing a large number of reaction products for somatostatin but very few for calcitonin. Thus, it was concluded that there was a considerable variation in somatostatin immunoreactivity of thyroid C cells from species to species.

Animals↗
PubMed1982

Degranulation and appearance of vesicular inclusions in canine C cells after administration of antithyroid drug.

When stimulated by the feeding of ethylenethiourea for a period of 6 months, dog thyroid glands increased to approximately 30 times their normal size. Not only follicular cells but also C cells had hyperplastic and hypertrophic features, compared with normal controls there was in the C cells a marked decrease in secretory granules immunoreactive for calcitonin. Furthermore, vesicular inclusions of various sizes and dilated nuclear enveloped, which showed a positive immunoreaction for calcitonin, were observed in the C cells. These findings indicate that the antithyroid drug interferes with synthesis of calcitonin by C cells probably by inhibiting the conversion of a larger precursor to calcitonin by C cells, probably by inhibiting the conversion of a larger precursor to calcitonin.

Animals↗