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Biomedical subjects

F Sasaki

Publications and source records attributed to F Sasaki.

At least 253 records · Page 14Linked to original sources
PubMed1983

Recognition patterns for exon-intron junctions in higher organisms as revealed by a computer search.

Most genes of higher eukaryotes are discontinuous. The DNA which codes for a protein is interrupted by introns. In the nucleus, certain machinery is supposed to recognize the exon-intron and intron-exon junctions. Applying computer searching to eighteen genes from various biological species, we examined what kinds of patterns or nucleotide sequences are necessary and sufficient to recognize the splice junctions. We propose that four common patterns of AG/GTA, /GTAAGT, RG/GTGAG and AG/GTXXGT, where R = A or G and X = A, T, G, or C, are often used as signals for exon-intron junctions. This proposal is based on the facts that they are not found in the exons of the genes examined and on the assumption that the recognition machinery scans the mRNA precursor from the 5'-end to the 3'-end.

Animals↗
PubMed1983

Role of the ovary in sexual differentiation of lactotrophs and somatotrophs in the mouse adenohypophysis: a stereological morphometric study by electron microscopy.

To study the effect of the ovary on sexual differentiation of somatotrophs and lactotrophs, the anterior pituitary glands of castrated adult male mice which had received an ovarian transplant during postnatal development were studied using a stereological morphometric technique with an electron microscope. In adult male mice which were castrated neonatally and given ovarian transplants at the age of puberty (NCT-males), the ovaries contained follicles and corpora lutea. The percentages (approximately 40) and numbers (approximately 2 x 10(5)) of lactotrophs were similar in normal dioestrous females and NCT-males, but were higher than the percentage (9.3) and number (4.6 x 10(4)) in normal males. Ovarian grafts in adult male mice which were simultaneously castrated and given an ovarian transplant just before puberty (PCT-males) contained numerous follicles of various sizes but no corpora lutea. The percentage (46.8) and number (3.9 x 10(5)) of lactotrophs were greater in these mice than in dioestrous females. The percentage of somatotrophs in NCT-males (34.7) was less than in normal males (52.6), but was similar to that in dioestrous female mice (37.4). The percentage of somatotrophs in PCT-males (27.4) was less than in normal male and dioestrous female mice. These data indicate that lactotrophs and somatotrophs differentiate to the female phenotype when a cyclically functional ovary is present after puberty.

Animals↗
PubMed1983

[Clinical evaluation of diagnostic methods of nodular goiter].

In 47 patients who had undergone roentgenography, ultrasonography, 201 Tl-scintigraphy, and aspiration cytology and on whom a pathological diagnosis had been made, the diagnostic value of the above-mentioned 4 examinations was evaluated. The correct diagnosis rate for aspiration cytology and 201 Tl-scintigraphy was 76.6%; for ultrasonography and roentgenography it was 70.2%. The false-negative rate of cancer for aspiration cytology was 14.9%; for the other examinations it was 10.6%. The false-negative rate upon combining 3 examinations, except roentgenography (soft tissue technique), proved to be 0% and 24 patients with thyroid cancer were preoperatively correctly diagnosed as "malignant" by means of the combination method.

Adult↗
PubMed1982

Establishment of an experimental model of human hepatoblastoma.

Establishment of xenografts or cell culture lines in which the alpha-fetoprotein (AFP) characteristic of clinical hepatoblastoma persists have been difficult. The serially transplantable strain (HB-3) of highly AFP-producing hepatoblastoma was successfully established in nude mice. And a highly AFP producing cell line (c-HB-3) is easily obtained by HB-3. This strain and line give us an ideal experimental model of hepatoblastoma in vivo and in vitro.

Animals↗
PubMed1982

Role of the ovary in the sexual differentiation of prolactin and growth hormone cells in the mouse adenohypophysis: a stereological morphometric study by electron microscopy.

The number of prolactin and growth hormone cells was estimated in the mouse anterior pituitary gland. During postnatal development in females, the number of prolactin cells showed a rectilinear increase from about 0.3 X 10(4) at 20 days of age to about 21 X 10(4) in adult female mice, while growth hormone cells gradually increased from about 7 X 10(4) on day 20 to about 20 X 10(4) on days 60-70, with a plateau level of about 14 X 10(4) cells around puberty. Prolactin cells were more abundant in adult female (about 21 X 10(4)) than in male (about 5 X 10(4)) mice, while there were fewer growth hormone cells in adult females (about 20 X 10(4)) than in males (about 25 X 10(4)). Ovariectomy before puberty induced the male pattern of pituitary development by inhibition of the increase in the number of prolactin cells and stimulation of that of growth hormone cells. In animals ovariectomized just before puberty (30-35 days of age) or 5 days after vaginal opening (40-45 days of age) the number of prolactin cells showed no further increase after the day of operation. On the other hand, when animals were ovariectomized at 10 days of age, the number of prolactin cells increased to the level found in 30-day-old normal control females. This implies that the increase in prolactin cells between 10 and 30 days of age is not dependent on the ovary, although after puberty the increase does depend on the presence of the ovary.

Animals↗
PubMed1982

[Hepatic regeneration after major hepatectomy in children].

Liver regeneration pattern and metabolic changes after major hepatectomy were studied comparatively in children and in adults and the results were obtained as follows: --The liver regeneration in children was more rapid than that in adults. The residual liver volume after major hepatectomy was restored to preoperative volume at 8 weeks after operation. --The shape of regenerated liver showed spheric. This feature was more significant up to the extent of the youth. --Serum protein was continued in low levels after operation and was never restored to preoperative value. --Serum transaminase level was increased more slightly in children and was normalized more rapidly. --Serum alkaline-phosphatase was increased gradually after operation.

Adolescent↗
PubMed1981

Alphafetoprotein in congenital biliary atresia and neonatal hepatitis.

Alphafetoprotein (AFP) production was investigated clinically and histologically in cases of congenital biliary atresia and neonatal hepatitis. While serum AFP levels were all higher than 16,000 ng/ml in seven patients with neonatal hepatitis, they were less than 10,000 ng/ml in 50 per cent of 12 patients with biliary atresia. Therefore, serum AFP levels below 10,000 ng/ml were suggestive of a diagnosis of biliary atresia. A number of AFP granules were identified in the liver cells and multinucleated giant cells in patients with neonatal hepatitis and biliary atresia, using an immunoperoxidase method. The serum AFP levels paralleled the number of cells with AFP granules. However, no characteristic differences in distribution of these granules occurred in the hepatic cells and giant cells. The AFP producing mechanism was qualitatively the same in neonatal hepatitis and biliary atresia. These phenomena suggest that congenital biliary atresia and neonatal hepatitis may have the same pathogenesis.

Bile Ducts↗