Search PubMed⌕ Search

Biomedical subjects

T Ohtani

Publications and source records attributed to T Ohtani.

At least 145 records · Page 8Linked to original sources
PubMed1987

[A recessive mutant causing testicular/ovarian teratoma in rats (Tera strain)].

A hereditary testicular/ovarian teratoma strain (Tera) of rats was developed from the Csk: Wistar-Imamichi strain. As the teratoma consisted of tridermic tissues such as bone, epithelium and neural tissue, it was diagnosed as triphyllomatous teratoma. The frequency of the teratoma was about 25% in either sex, with no sexual difference. Accordingly, the heredity of the teratoma appeared to be an autosomal single recessive trait (symbol, tera).

Animals↗
PubMed1986

Diagnostic accuracy of ultrasonography for hepatocellular carcinoma.

Accuracy of ultrasonography for the diagnosis of hepatocellular carcinoma (HCC) was examined. The subjects were 5339 patients who underwent ultrasonography of the upper abdomen, during the year 1980 at our hospital. Out of 5339, 113 cases were found to be hepatocellular carcinoma by a 3-year follow-up study, checking against the records of regional cancer registry. Diagnostic accuracy based on 6 months of follow-up was as follows: for identification of liver tumors, sensitivity, specificity, and overall accuracy were 94.9%, 98.7%, and 98.9% respectively; for diagnosis of HCC, sensitivity, specificity, and overall accuracy were 58.9%, 99.9%, and 99.3% respectively. In conclusion, the ability of ultrasonography to detect hepatocellular carcinoma is adequately high, and thus, ultrasonography can be employed as a diagnostic procedure for mass screening.

Carcinoma, Hepatocellular↗
PubMed1986

Differential modulation of chorionic gonadotropin (CG) subunit messenger ribonucleic acid levels and CG secretion by progesterone in normal placenta and choriocarcinoma cultured in vitro.

The ability of progesterone to modulate the production and secretion of human CG (hCG) in both normal placenta and choriocarcinoma was compared by culturing explants of each trophoblastic tissue in the presence or absence of progesterone. The cellular level of messenger RNAs (mRNAs) encoding hCG alpha, hCG beta, and human placental lactogen (hPL) were quantitatively estimated by mean grain count per syncytial nucleus on the tissue sections hybridized in situ with labeled complementary DNA probes corresponding to these mRNAs. Immunoreactive hCG, hCG alpha, and hCG beta in the media and explanted tissues were measured by the homologous RIAs, and hPL was assayed by hPL-RIA kit. Addition of progesterone at concentrations of 5-20 micrograms/ml into the culture of normal early placenta caused a decrease in the cellular levels of hCG alpha mRNA and hCG beta mRNA after a 24-h culture, and exhibited a decline in immunoreactive hCG and hCG alpha levels released into the media together with a decrease in immunoreactive hCG alpha and hCG beta levels in the explanted tissues after a 48-h culture. The addition of progesterone neither affected the cellular levels of hPL mRNA nor immunoreactive hPL levels in the media and tissues. On the other hand, addition of 17 beta-estradiol at concentrations similar to those used with progesterone did not alter the levels of immunoreactive hCG and hCG alpha in the media or explanted placental tissues, while lower concentrations (1-10 ng/ml) of 17 beta-estradiol caused an increase in immunoreactive hCG alpha levels in the media and cultured tissues. These findings suggest that the suppressive effect observed with progesterone is not likely to be a toxic effect of steroid, but is rather selective on hCG production and secretion by normal placenta. Thus, progesterone may be a factor responsible for the inhibitory regulation of hCG production and secretion by normal placenta. However, in contrast to normal placenta, the choriocarcinoma culture in vitro did not respond to progesterone. The steroid was without significant effect on the cellular levels of hCG alpha mRNA and hCG beta mRNA, and on the levels of immunoreactive hCG and hCG alpha in the media and explanted tissues. These results suggest that the inhibitory regulation of hCG production and secretion in choriocarcinoma is different from that in normal early placenta.

Choriocarcinoma↗
PubMed1986

Endoscopic ultrasonography of lymph nodes surrounding the upper GI tract.

We investigated the usefulness of endoscopic ultrasonography (EUS) of lymph nodes surrounding the upper GI tract and tried the enhanced EUS by the method of the oral administration of '10% oil-in-water-type emulsion.' The results were as follows: The ultrasonographic visualization rate of lymph nodes surrounding the esophagus was 33.7% in total; however, it was 43.4% for those greater than 5 mm and 58.7% for those greater than 10 mm. The frequency of lymph node metastasis of esophageal cancer was 48.1% for those larger than 10mm with a round shape and 14.3% for the same size with an ellipsoid shape; for those less than 10mm, it was also low. Lymph nodes surrounding the esophagus and the stomach were enhanced by administration of 10% oil-in-water-type emulsion. The visualization rate of lymph nodes can be increased by using this new method. Endoscopic ultrasonography is very useful for the detection of swelling lymph nodes surrounding the upper GI tract before the operation.

Endoscopy↗
PubMed1985

Evaluation of the severity of hypoxanthine-guanine phosphoribosyltransferase deficiency using viable T cells.

Peripheral T cells from 3 Lesch-Nyhan patients, 3 normal subjects, and 3 brothers with hypoxanthine-guanine phosphoribosyltransferase (HGPRT) deficiency but without Lesch-Nyhan syndrome (so-called partial deficiency) have been analyzed. Although these brothers contained HGPRT activities neither in the hemolysates nor in the T cell extracts at levels detectable by the regular radioenzyme assay, the enzyme deficiency had not caused any typical neurological symptoms of the Lesch-Nyhan syndrome. Although the T cells from these brothers were at least 10-fold more resistant to 6-thioguanine than normal T cells, they were more than 30-fold less resistant than the T cells from 3 Lesch-Nyhan patients indicating that there is a clear difference in the severity of the enzyme deficiency between the brothers and the Lesch-Nyhan patients. These data indicate that the long-term T cell culture in the medium containing a purine analog whose toxicity depends on a salvaging enzyme is useful for evaluating the severity of the enzyme deficiency in viable cells.

Adolescent↗
PubMed1985

Beneficial effects of high-dose intravenous gammaglobulin on the accelerated phase of Chediak-Higashi syndrome.

The Chediak-Higashi syndrome (CHS) is a rare, autosomal-recessively inherited disease characterized by giant cytoplasmic granules in neutrophils, monocytes and lymphocytes. It has been reported that a lymphoma-like illness develops in the accelerated phase of the syndrome and that early death ensues. Treatment of CHS has not been established, particularly when the accelerated phase develops. We treated a 15-year-old boy, who had entered into the accelerated phase, with high-dose intravenous gammaglobulin. The treatment was beneficial in the management of accelerated phase of CHS.

Adolescent↗
PubMed1984

A case report of T-cell lymphoma with suppressor phenotype and helper function for immunoglobulin synthesis.

A patient with T-cell lymphoma is presented. The morphologic features of a biopsied lymph node were consistent with adult T-cell lymphoma with hypergammaglobulinemia, and most of the lymph node cells were reactive with monoclonal antibody OKT8, which detects suppressor/cytotoxic T lymphocytes. However, in a pokeweed mitogen-driven test system in which the capability of T lymphocytes to help or suppress the differentiation of B lymphocytes is measured, the lymphoma cells induced immunoglobulin synthesis of B lymphocytes, thus providing helper function. As far as we know, this is the first report on T-cell lymphoma having suppressor phenotype and helper function for immunoglobulin synthesis.

Antibodies, Monoclonal↗
PubMed1984

Trabecular microfractures in the acetabulum. Histologic studies in cadavers.

The distribution of trabecular microfractures was studied in 39 cadaveric acetabula. The mean age of the group with microfractures was 71 years and the mean age of the group without fractures was 60 years. Most of the microfractures were located at the subchondral, weight-bearing portion of the acetabulum. Our observations suggest that trabecular microfractures are involved in the formation of bone cysts.

Acetabulum↗
PubMed1983

ATP-dependent unwinding of the double helix and extensive supercoiling by Escherichia coli recA protein in the presence of topoisomerase.

recA protein, which is essential for genetic recombination in Escherichia coli, causes extensive unwinding of the double helix by an ATP-dependent reaction and accumulation of positive supercoiling in closed circular double-stranded DNA. Initiation of the extensive unwinding was largely dependent on homologous single-stranded DNA. Therefore, it is likely that the extensive unwinding is initiated mainly at the site of D-loops. "Nascent D-loops" in which the two DNA molecules did not interwind were also good initiation sites of extensive unwinding. When the concentration of Mg2+ was decreased from the standard conditions for D-loop formation (13 mM MgCl2; the higher Mg2+ condition) to the lower Mg2+ condition (1 to 2 mM MgCl2), extensive unwinding by recA protein was initiated very quickly in the absence of single-stranded DNA. Results showed that this single-stranded DNA-independent initiation of extensive unwinding (i) requires negative superhelicity of the double-stranded DNA and (ii) is a first order reaction with respect to the DNA. These observations suggest that, under the lower Mg2+ condition, the extensive unwinding starts at a transiently denatured site in the negative superhelical DNA. Once initiated, the unwinding by recA protein is propagated extensively, even under conditions that do not allow its initiation. Therefore, the propagation of unwinding is a processive reaction ("processive unwinding"). Previous studies indicated that recA protein promotes "distributive unwinding" of double helix which depends on single-stranded DNA. Therefore, recA protein promotes unwinding of the double helix by either of two distinct pathways. Stress caused by the processive unwinding could explain the dissociation of D-loops and reversible inactivation of the double-stranded DNA in a D-loop cycle.

Adenosine Triphosphate↗