Search PubMed⌕ Search

Biomedical subjects

R Kubota

Publications and source records attributed to R Kubota.

At least 109 records · Page 6Linked to original sources
PubMed1990

CD4+CD8+ thymocytes are susceptible to DNA fragmentation induced by phorbol ester, calcium ionophore and anti-CD3 antibody.

Stimulation of murine thymocytes with phorbol ester or calcium ionophore for 18-24 h resulted in 70%-80% fragmentation of DNA into 180-200-bp multiples, followed by cell death. Experiments with fractionated subpopulations by panning or flow cytometry revealed that DNA fragmentation was selectively observed in CD4+CD8+ cells and in a portion of CD4-CD8+ cells. To investigate whether DNA cleavage is also inducible via antigen-specific receptors, thymocytes were incubated in wells precoated with anti-CD3 antibody. An approximately 20% increase of DNA fragmentation was constantly observed when unseparated thymocytes were stimulated with anti-CD3 antibody. In this anti-CD3-induced DNA degradation, CD4+CD8+ cells are probably the target cells, since (a) fetal thymocytes at day 18 of gestation were found vulnerable to anti-CD3-induced DNA cleavage and (b) flow cytometry analysis of viable cells recovered after cultivation in the anti-CD3-coated wells revealed that CD4+CD8+ cells were preferentially decreased. Further experiments with purified CD4+CD8+ cells, however, could not define a clear-cut increase of DNA fragmentation when isolated CD4+CD8+ cells were stimulated with anti-CD3 antibody. Addition of interleukin (IL) 1, IL 2, IL 3, IL 4 or interferon-gamma to the CD4+CD8+ cell cultures failed to yield a DNA cleavage similar to that of unseparated thymocytes.

Animals↗
PubMed1990

T1 and T2 relaxation times on gadolinium-diethylenetriaminepentaacetic acid enhanced magnetic resonance images of brain tumors.

MRI of brain tumors was performed with CPMG pulse sequence, and T1 and T2 relaxation times were measured before and after the administration of 0.1 mmol/kg Gd-DTPA. T1 and T2 became significantly shorter than before with the T1 shortening being about twice the T2's. Three types of T2 shortening were classified by the difference in the intra-tumoral transport of Gd-DTPA in the time-course study after the administration. Transportal activity of Gd-DTPA seemed to be reflected by the physiologic viability of tumor suggested by pre-contrast T2.

Adolescent↗
PubMed1990

[Study of the fine structure of human deciduous dentin with dentinogenesis imperfecta, with special reference to the mantle dentin].

A lower deciduous incioer exhibiting dentinogenesis imperfecta (D.I) obtained from a 6-year-old boy with osteogenesis imperfecta (Shields' Type I) was examined by means of light microscopy (LM), scanning electron microscopy (SEM), and X-ray microanalysis (XMA). With LM, the dentin displayed a sparse and irregular tubular pattern near the dentino-enamel junction (DEJ) and only few or no tubular structures in the area corresponding to the circumpulpal dentin. Between these two areas, cleft-like structures were characteristically noted. Structural irregularities in the dentinal tubules were also shown with SEM observation. XMA demonstrated that the distribution of both Ca and P in the dentin of DI teeth was apparently lower than that in the normal deciduous incisor used as a control. Specifically, an area along EDJ at a distance of 25-35 microns, corresponding to the mantle dentin, revealed extremely low or no distribution of the both elements. From the present observation, it is suggested that the generic disorder mainly involved in the primary odontoblasts and consequently results in the disturbance of calcification, especially that mediated by the matrix vesicles, and shortening of the cell life. After the death of these cells, the cells originate in, from the undifferentiated pulp cells may participate in the deposition of another irregular dentin.

Calcium↗
PubMed1989

Two cases of necrotizing myelopathy associated with malignancy caused by herpes simplex virus type 2.

Two cases of necrotizing myelopathy were autopsied; one was complicated with lung carcinoma and the other with chronic type adult T cell leukemia (ATL leukemia). To our knowledge, they were the first cases of their type in Japan. In both cases, necrosis of the spinal cord was observed in the gray and white matter along most of its extent. Marked changes were found in the lumbar segment. The patients were not treated with intravenous cancer chemotherapy or irradiation. Immunohistochemical and electron microscopic examination revealed an extremely strong infection of herpes simplex virus (HSV) type 2. However, HSV type 1 and cytomegalovirus antigens were not detected.

Adenocarcinoma↗
PubMed1989

In vitro modulation of lymphocyte proliferation by prednisolone and interferon-alpha in patients with HTLV-I-associated myelopathy (HAM).

One of the hallmarks of human T-lymphotropic virus type I (HTLV-I) infection is the proliferation in vitro of peripheral blood lymphocytes (PBLs) in the absence of growth factors. This phenomenon, the autologous proliferative response (APR), involves spontaneous growth of HTLV-I-infected T-cells and proliferation of T-cells in response to the infected cells. We studied the modulating effect of prednisolone (PSL) and interferon-alpha (IFN) on APR of PBLs obtained from five patients with HTLV-I-associated myelopathy (HAM). APR was significantly inhibited by PSL and IFN suggesting that APR is important in the pathogenesis of HAM.

Adult↗
PubMed1989

Activated T lymphocytes in cerebrospinal fluid of patients with HTLV-I-associated myelopathy (HAM/TSP).

In order to detect activated T lymphocytes in the cerebrospinal fluid (CSF) of patients with human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP), we studied CSF lymphocytes in untreated patients with HAM/TSP and other neurological diseases (OND). Dual-immunofluorescence staining technique was performed using fluorescence microscopy. No significant difference in the CD4+/CD8+ ratio of CSF lymphocytes was observed between HAM/TSP patients and patients with OND. However, both CD4+ and CD8+ CSF lymphocytes of HAM/TSP patients contained higher percentages of HLA-DR-positive cells than those of patients with OND (P less than 0.05), suggesting that the activated CSF T lymphocytes were composed of both CD4+ and CD8+ subsets in patients with HAM/TSP.

Antibodies, Monoclonal↗
PubMed1989

Rapid and sensitive response of carbon-11-L-methionine tumor uptake to irradiation.

Evaluation of cancer treatments by the measurement of tumor size is an unsatisfactory method for the observation of the radiobiologic response of the tumor. After 20 Gy single-dose irradiation of 60Co to rat tumor AH109A, the L-[methyl-11C] methionine tumor uptake, the microscopic extension of tumor necrosis and the shrinkage of tumor were compared quantitatively. L-[Methyl-11C]methionine uptake fell to 54 +/- 19% of non irradiated tumor at 12 hr after irradiation. Necrosis extended 49 +/- 7% of total tissue volume after 3 days. Tumor volume decreased 48 +/- 12% 10 days after irradiation. L-[Methyl-11C]methionine uptake by tumor showed a sharp and rapid linear decrease after irradiation and the response of the uptake to irradiation preceded the extension of necrosis and tumor shrinkage. We conclude that radiation effect on the tumor may be evaluated immediately after irradiation by the measurement of L-[methyl-11C]methionine uptake and thus clinical application of positron emission tomography may give a benefit to the patients undergoing radiotherapy.

Animals↗
PubMed1987

Growth and differentiation of teratocarcinoma OTT6050 affected by host hormonal changes in old mice.

We previously reported the age and sex dependent decrease in the growth rate of teratocarcinoma OTT6050. Studies of the effects of hormones on the tumor growth are presented here. Age related changes in the serum levels of triiodothyronine, thyroxine, progesterone, testosterone and estradiol that increase in the young adult and decrease in the old were observed with radioimmunoassay. Administration of estradiol to tumor-bearing, 50 week-old female mice increased the tumor growth rate to that of 10 week-old mice. Tumor growth rates in estradiol-treated 10 week-old female and male mice were slightly accelerated compared to the control, but not as fast as that of control juveniles. It can be concluded that extrinsic estradiol stimulates the teratocarcinoma growth in vivo especially in old female mice. Age-dependent decline of the growth rate of teratocarcinoma in the female is due partly to changes in estrogen level.

Aging↗
PubMed1987

Metastatic enhancement and growth inhibition by glucocorticoid and its receptors in mouse teratocarcinoma OTT6050 in vivo.

To elucidate the mechanism of glucocorticoid-induced metastases and growth inhibition of mouse teratocarcinoma OTT6050, syngeneic 129/Sv-CP+SlJ mice were subcutaneously (s.c.) injected with the tumor and treated with daily intraperitoneal (i.p.) injections of hydrocortisone in doses of 1.5 to 12.5 mg per mouse. The number of lymph-node and visceral metastases was greatly increased by the treatment with hydrocortisone unrelated to the doses and sexes. Tumor growth (the products of three principal diameters) of lymph-node metastases was dose-dependently inhibited by the treatment. Histologically, lymph-node metastatic tumors contained large masses of well-differentiated tissues compared with the s.c. transplanted tumor of the same size. The glucocorticoid receptors were measured using dextran-coated charcoal adsorption techniques with [3H] hydrocortisone. Glucocorticoid receptor contents were higher in lymph-node metastatic tumor (100 fmole/mg cytoplasmic protein, mean) than in s.c. transplanted tumors (74.5 fmole/mg, mean) respectively treated with 12.5 mg of hydrocortisone. The metastatic growth inhibition by hydrocortisone might be closely related to the receptor-mediated mechanisms and histological differentiation.

Animals↗
PubMed1986

Abortion counseling.

Explore the source record for details and available documents.

Abortion, Spontaneous↗
PubMed1984

Differences of the growth of mouse teratocarcinoma OTT6050 induced by various sex hormone treatments in vivo.

To study why the tumor growth rate was different among host mice of different sexes and ages, we examined the role of sex hormones in the growth and development of mouse teratocarcinoma OTT6050 in vivo. Estrogen and progesterone showed enhancement of tumor growth, while ovariectomy resulted in partial growth inhibition. Testosterone, orchiectomy, and antiestrogen had no effects. We concluded that the differences in tumor growth rate in females of different ages were due to changes in serum estrogen and progesterone levels and that the constancy of the growth in adult males was due to absent effects of testosterone.

Age Factors↗
PubMed1983

Effects of estrogen on the growth of mouse teratocarcinoma OTT6050 in vivo.

The effects of estrogen, antiestrogen and ovariectomy on the growth of a mouse teratocarcinoma, OTT6050, were studied in vivo. Subcutaneous tumors transplanted in syngeneic 129/Sv male and female mice were measured, and tumor-growth curves were constructed using the products of three principal tumor diameters, designated tumor volume. There was a linear correlation between the measured tumor volume and the actual excised tumor volume. The tumor growth rate in estrogen-treated groups was significantly greater than that in the control group, and the difference in tumor volume between treated groups and controls increased with time. However, dose responsiveness was not observed. In antiestrogen-treated or ovariectomized mice, tumor growth was partially inhibited only at the early stages. The mean survival time of estrogen-treated and ovariectomized groups was shorter than that of controls, while that of the antiestrogen-treated group was identical to that of controls. Histologically, no specifically different types of differentiated tissues were observed in any group. Our experiments show that estrogen is one important factor which stimulates the growth of one form of teratocarcinoma.

Androstanols↗