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Biomedical subjects

S Yamashiro

Publications and source records attributed to S Yamashiro.

162 records · Page 9Linked to original sources
PubMed1980

Ultrastructural study of liver fibrosis in turkeys fed diets containing rapeseed meal.

Livers of turkeys fed low and high glucosinolate rapeseed meal diets for 16 weeks were examined ultrastructurally. Hepatocytes from birds fed on Tower rapeseed meal (0.15 mg of glucosinolate per g) showed a mild accumulation of lipid droplets and an apparent increase in lysosomes and microbodies. The parenchymal cells of the livers of turkeys fed on Target Rapeseed meal (9.50 mg of glucosinolate per g) exhibited varying degrees of degenerative change: dilation of endoplasmic reticulum, swelling of mitochondria with fragmentation and loss of cristae, presence of autophagic vacuoles, myelinoid bodies, electron-dense lipidlike droplets, vesiculation of cytoplasm and necrosis of the hepatocytes. The electron-dense lipidlike bodies were most frequent at the biliary pole. Sinusoids near the degenerating hepatocytes were often disrupted and perisinusoidal mesenchymal cells in the area showed distended cisternae of granular endoplasmic reticulum. Such cells or fat-storing cells were frequently seen in the vicinity of proliferated collagen fibrils and degenerating hepatocytes. These observations suggest that degenerative alterations of hepatocytes accompanied or preceded the development of fibrosis in turkeys fed rapeseed meal high in glucosinolate.

Animal Feed↗
PubMed1979

Ultrastructural alterations of the myocardium of rats fed rapeseed oils.

Ultrastructural studies were conducted on the myocardium of rats fed corn oil, Tower RSO (0 . 88 per cent EA), 1788 RSO (3 . 6 per cent EA) and Target RSO (38 . 9 per cent EA) supplemented diets for 18 weeks. Cardiac myocytes of Tower RSO-fed rats showed some loosening of myofibrils and a slight increase in the number of mitochondria, few of which had lost their cristae. Large intravascular lipid droplets were observed in the myocardium of rats fed the 1788 RSO diet, as well as some small lipid droplets which were seen in close association with mitochondria. There was an apparent increase in the number of mitochondria of both normal and giant size. Many of the mitochondria exhibited distortion of shape and degeneration of cristae. The matrix of megamitochondria contained vesicles and electron-dense floccular inclusions and at times electron-lucent lipid-like material. The degenerative changes of mitochondria were most pronounced in the Target RSO group, where some megamitochondria showed a complete loss of cristae and a replacement of matrix with lipid-like material. These observations suggest that both intravascular lipid globules and the mitochondrial alterations are possible contributory factors involved in the development of cardiac lesions in RSO-fed rats.

Animals↗
PubMed1978

Growth and cytogenetic characteristics of nickel sulphide-induced rhabdomyosarcomas in rats.

Rhabdomyosarcomas induced by single intramuscular injections of nickel sulphide (Ni3S2) in Fischer and Hooded rats were cultured in vivo and in vitro to study their growth characteristics and chromosomal constitution. The tumor cell suspensions cultured in vitro exhibited more myogenic differentiation on the coverslips than those cells grown in vivo in diffusion chambers. A characteristic feature of in vivo cultures was the appearance of microclusters which resembled the primary tumors. Chromosome analyses of primary tumors revealed that a majority of these had a modal number in the diploid or near diploid range. Fischer rat primary tumor cells exhibited abnormal configurations including rings, dicentrics and triradials. A comparison of the chromosome make-up of the primary tumors and their metastases was performed on four sets of tumors. Three out of four metastases examined showed the diploid chromosome make-up characteristic of the primary tumors suggesting that the tumors with the diploid or near diploid chromosome constitution are more likely to produce metastases.

Animals↗
PubMed1978

Ultrastructure of livers of broiler chickens fed diets containing rapeseed meal.

The ultrastructure of the livers of four-week-old White Rock broiler chickens fed diets containing 50% rapeseed meal was examined. Multifocal hepatocytic necrosis was observed in most of the birds fed the experimental diets. Early degenerative changes were swelling of mitochondria and vacuolations of various sizes in the cytoplasm of the hepatocytes. The reticulum fibres seen as bundles of cross striated fibrils were disorganised at the sites of the focal necrosis. Alteration of interfibrillar matrix were considered to be reason for the negative silver stain in the necrotic foci at light microscopic level reported previously. Disruption of the liver framework at the necrotic foci appeared to have caused a rupture of the sinusoids in the birds showing the haemorrhagic syndrome.

Animal Feed↗
PubMed1978

Histopathology of the heart from rats fed rapeseed oils.

The cardiopathogenicity of oils from new, low erucic acid (EA) rapeseed, Brassica napus, cv Tower (0.88 per cent EA) and Brassica napus, cv 1788 (3.6 per cent EA) were tested on rats following 18 weeks of feeding. Oil from Brassica napus, cv Target, with 38.9 per cent EA served as a positive control and corn oil as the negative control. Tower and 1788 rapeseed oils showed noticeable cardiopathogenicity, and a few mild lesions were also noted in the corn oil group. The main pathological change was from fresh to relatively old foci of myocardial necrosis. The presence of droplets accompanying the platelet aggregates suggested the possibility of their involvement in the development of the lesions. The pathological changes in the small and minute blood vessel walls were interpreted as one of the predisposing factors for the development of fatty embolism and subsequently of myocardial necrosis.

Animals↗
PubMed1977

The effects of original and randomized rapseed oils containing high or very low levels of erucic acid on cardiac lipids and myocardial lesions in rats.

The nutritional status of the very lowerucate, rapseed oil, Brassica napus var. 'Tower,' was compared with that of the high-erucate oil, Brassica napus var. 'Target,' as well as with corn oil. The effect of randomization on the nutritional qualities of rapeseed oil was investigated as well. The feeding of diets containing the original and randomized 'Tower' oil or the original 'Target' oil, at the 20% level by weight, gave growth rates which were not significantly different from that for corn oil. However, the randomized 'Target' oil gave growth rates which were significantly less than all other groups. The growth results could not be explained simply on the basis of food consumption. The level of triglycerides in the hearts of rats fed the very low-erucate oils was not significantly different from the corn oil group. Triglyceride concentrations in the hearts of animals given the high-erucate oils were 7-12 times greater than all other groups. The level of total fatty acids in tissue phospholipids was the same regardless of dietary treatment. Fatty acid compositions of the tissue lipid were the same in animals fed either the original or randomized rapeseed oils. A much higher incidence of focal myocardial necrosis was found in animals receiving high-erucate rapeseed oil relative to animals given the corn oil. The incidence in rats fed diets containing very low-erucate rapeseed oil was intermediate between these latter two extremes.

Animals↗
PubMed1977

Intravascular fat globules in the heart of pigs fed rapeseed meals.

Histopathological studies were conducted on growing pigs fed a corn, soybean meal control and two experimental diets supplemented with either a high or a low glucosinolate rapeseed meal. A high incidence of intravascular large fat globules in the heart with mild interstitial oedema was observed in the boars on high glucosinolates in comparison with the boars on low glucosinolates rapeseed meal. Boars and gilts on the corn, soybean meal control diet showed no intravascular fat globules.

Animal Feed↗
PubMed1977

Liver fibrosis of the turkey on rapeseed products.

Sclerosis of the liver accompanied by hydropericardium of long standing was observed in turkeys fed rapeseed products for 16 weeks. Histologically, extensive increases of fibrous tissue composed predominantly of reticular fibres and centrilobular degeneration of parenchymal cells were the main pathological features. Neither prominent fatty degeneration nor the formation of pseudolobules was observed. The birds fed rapeseed products for four and 12 weeks showed continuing occurrence of multiple focal and/or solitary hepatocytic necroses preceding the process of fibrosis in the livers. Glucosinolates and their hydrolytic products were considered the most likely causative factors for the hepatocytic necrosis.

Animal Feed↗
PubMed1977

Haemorrhagic liver syndrome of broiler chickens fed diets containing rapeseed products.

Haemorrhagic livers were observed in male white rock chicks of one to four weeks old, that were fed diets supplemented with 50 per cent rapeseed meal and 50 per cent rapeseed full-fat seeds. The haemorrhagic lesions were comparable to those of the laying hens except for the absence of fatty degeneration. There were no substantial fibrotic lesions. Multifocal or solitary hepatocytic necrosis was observed around the haemorrhagic lesions, although the necrotic foci did not always accompany the haemorrhage. The reticulum only of the necrotic and haemorrhagic lesions was not demonstrated with silver strain. Association of hepatocytic necrosis with liver haemorrhage and absence of argyrophilic fibres suggested that the hepatocytic necrosis was the primary contributory factor for the development of the hepatic haemorrhage.

Animal Feed↗
PubMed1975

Fatty haemorrhagic liver syndrome in laying hens on diets supplemented with rapeseed products.

Livers of laying hens of Hy-Line No 934E on low erucic acid rapeseed meals and rapeseed oil were studied. Gross lesions in the livers of hens on experimental diets were moderate to severe fatty degeneration, focal necrosis and moderate to severe haemorrhage. Histological examination revealed oedematous foci and lysis of hepatocytes along with large amounts of lipid droplets in the necrotic lesions. Necrotic lesions were not always associated with large haemorrhages. Connective tissue infiltration of older degenerative and haemorrhagic lesions was not extensive. Abdominal haemorrhage from livers occurred when extensive necrosis in the form of hepatocyte lysis and some vascular changes were present, suggesting hepatocytic degeneration caused by toxic products or their metabolites present in rapeseed by-products.

Animals↗
PubMedDate not supplied

Ethanol potentiation of methyl mercury toxicity: a preliminary report.

The ability of ethanol to affect hindlimb ataxia and body weight changes induced by methyl mercury was studied in rats. Animals treated with either water or ethanol increased in body weight during the experiment and showed no impairment of hindlimb movement. Rats treated with methyl mercury also increased in body weight but developed moderate hindlimb ataxia. Animals treated with ethanol and methyl mercury initially gained but subsequently lost weight and exhibited severe hindlimb ataxia. The results provide evidence that ethanol can potentiate methyl mercury toxicity in rats and, by implication, in humans.

Animals↗
PubMedDate not supplied

Correlative light optical, scanning electron, and transmission electron microscopy of skeletal muscle in muscular dystrophy and muscular atrophy: a pilot study.

Biopsies of skeletal muscle from three different cases of muscular dystrophy and one case of spinal muscular atrophy that has been fixed with Karnovsky's fluid were either routinely prepared for scanning electron microscopy (SEM) or were frozen to -20 degrees C and sectioned on a steel knife in a cryostat at 5-10 micrometer. The sections were coverslipped and examined using a light microscope equipped with polarizing optics (Pol). After areas were selected, the sections were prepared for SEM and thereby examined. The tissues on the slides that had been observed with light microscopy (LM) and SEM were prepared further for transmission electron microscopy (TEM) by infiltrating them with Epon and cutting sections at approximately 100 nm on an ultramicrotome. It is shown that the stage of contraction in one pathologic myofiber may vary along its length. The following advantages may be realized by using correlative (Pol leads to SEM leads to TEM) microscopy on skeletal muscle biopsies: 1) lesions can be differentiated from "normal" surrounding tissue; 2) doubtful structures can be reexamined with the SEM and TEM; and 3) the SEM image of different states of muscle contraction can be reinterpreted in the light of the Pol or TEM image.

Adolescent↗
PubMedDate not supplied

Development of the thoracic air sacs of turkeys with age and rearing conditions.

Cytology and structure of the thoracic air sac of turkeys were investigated at four different ages (26-day embryo, 1 day, 2 wk, and 10 wk old) and two rearing conditions (isolation and commercial). Cytology was performed by guided fiberoptic endoscopy on the left thoracic air sac of each bird. The right thoracic air sac was sampled for light and electron microscopy. Heterophils were the most common nonepithelial cell found in air sac fluid. followed by macrophages and lymphocytes. Macrophages were most abundant in 1-day-old turkeys and turkeys raised in commercial conditions. The epithelium of the air sac consisted of squamous and cuboidal cells, with a few ciliated columnar and nonciliated columnar cells. Cuboidal cells had similar characteristics to type II pneumocytes. The mucociliary system was organized in tracts extended from the ostium to the posterior parts of the air sac. The number of ciliated tracts decreased with age, and the air sacs of commercial turkeys had a larger proportion of ciliated epithelium than did those of isolation birds. The epithelium may protect against disease by a structured mucociliary transport system, the production of surfactant, and phagocytosis of foreign particles. Differences in cytology and structure may reflect the maturation of the immune system and/or response to environment.

Aging↗