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Biomedical subjects

R Takahashi

Publications and source records attributed to R Takahashi.

At least 19 recordsLinked to original sources
PubMed1992

Changes in growth and tumorigenicity following reconstitution of retinoblastoma gene function in various human cancer cell types by microcell transfer of chromosome 13.

Functional loss of the retinoblastoma (RB) gene has been implicated in the initiation or progression of several human tumor types including cancer of the eye, bone, bladder, and prostate. To examine the consequence of adding one RB allele containing its normal regulatory elements back into representative examples of each of these cancer types, as well as to compare the results to those previously reported using various RB complementary DNA constructs, a neomycin resistant marked 13 chromosome was transferred by microcell fusion. Several attempts to obtain RB positive osteosarcoma cells failed. In addition, only one RB positive retinoblastoma clone was isolated. This clone contained many large cells, could not be maintained in long-term culture, and produced only RB negative tumors. Three RB positive bladder cancer cell clones were obtained, all of which grew slower in culture than their RB negative parental counterpart and did not form colonies in soft agar. Tumorigenicity was markedly suppressed in these clones. One clone yielded no tumors, and the other 2 clones produced only one small tumor each, both of which were RB negative. In contrast, the 2 RB positive prostate cancer cell clones isolated had no differences in their cell culture growth properties, including growth in soft agar compared to the parental cells. One of the clones was nontumorigenic, while the other clone produced 4 small tumors, all of which were RB positive. These results indicate that the transfer of one RB allele by microcell transfer produces different levels of growth inhibition as well as tumor suppression, depending on the cell type examined. In the case of prostate cancer, the function of the RB gene in tumor suppression appears to be independent from its growth regulatory function, since no growth inhibition in cell culture was noted in these cells, although tumor suppression was significant.

Alleles↗
PubMed1992

Modified Van Praagh's operation for interrupted aortic arch with severe subaortic stenosis in a neonate.

A 26 day old neonate with Type B interrupted aortic arch, a ventricular septal defect and severe subaortic stenosis underwent a successful modified Van Praagh's operation, consisting of insertion of a graft between the main pulmonary artery and descending aorta, ligation of the patent ductus arteriosus and main pulmonary artery banding distal to the graft. This palliative procedure was effective and easily performed without the aid of cardiopulmonary bypass even in this severely ill neonate with such a complex defect.

Abnormalities, Multiple↗
PubMed1992

Treatment of tardive dyskinesia with ceruletide: a double-blind, placebo-controlled study.

The effectiveness of a once-weekly i.m. injection of ceruletide (0.8 microgram/kg) in suppressing the symptoms of neuroleptic-induced tardive dyskinesia (TD) was evaluated in a double-blind, placebo-controlled, matched-pairs study. Global evaluation of the severity of TD symptoms over the 8-week study period revealed a significant improvement with ceruletide as compared with placebo. Analysis of the therapeutic response to ceruletide over the course of treatment revealed a slow, but long-lasting improvement of TD symptoms. Side effects, which were mild and transient, consisted mainly of nausea and epigastric discomfort. The incidence of side effects did not differ between the ceruletide- and placebo-treated groups. Ceruletide appears to be a novel and practical treatment that can substantially alleviate the symptoms of dyskinesia.

Adult↗
PubMed1992

Analysis of the human tyrosine hydroxylase promoter-chloramphenicol acetyltransferase chimeric gene expression in transgenic mice.

To investigate cis-elements responsible for catecholaminergic (CAnergic) neuron-specific expression of the tyrosine hydroxylase (TH) gene, we produced lines of transgenic mice carrying 5.0-kb, 2.5-kb and 0.2-kb fragments from the 5'-flanking region of the human TH gene fused to a reporter gene, chloramphenicol acetyltransferase (CAT), and designated them as TC 50, TC 25, and TC 02, respectively, and reporter gene expression in transgenic mice was analyzed by CAT assay by immunocytochemistry with anti-CAT antibody. High-level CAT expression was observed in the brain and adrenal gland using the 5.0-kb promoter of the TC 50 mice, but ectopic expression was consistently observed in several somatic tissues, e.g. thymus, colon, and testis. In brain, expression was achieved in CAnergic neurons with the largest construct (5.0 kb), but not with 2.5 kb or 0.2 kb of 5' flanking sequence. However, TC 50 mice also expressed CAT immunoreactivity in non-CAnergic neurons. In the TC 25 line CAT immunoreactivity was detected only in some non-CAnergic neurons. In the TC 02 line no CAT immunoreactivity was detected in any of the tissues examined. These results indicate that the 5.0-kb DNA fragment of the TH gene upstream region contains activity to express CAT in CAnergic neurons and surprisingly, lacks some regulatory elements attenuating ectopic expression, and that the 2.5-kb and 0.2-kb fragment are not sufficient for the proper expression. We discuss the presence of the tissue-specific regulatory elements in the structure portion of the TH gene and/or 3'-flanking region.

Animals↗
PubMed1992

Oxidative damage to the membrane of canine erythrocytes with inherited high Na, K-ATPase activity.

Oxidative damage to the membrane in canine erythrocytes with inherited high Na, K-ATPase activity (HK cells) was compared with that in normal canine cells (LK cells). When 30 mM beta-acetylphenylhydrazine (APH) was applied to HK and LK cells, lipid peroxidation and hemoglobin denaturation occurred. Lipid peroxidation determined from malondialdehyde (MDA) formation was significantly lower in HK than in LK cells so far as endogenous glutathione (GSH) concentration was maintained at appropriate levels. With the depletion of GSH, MDA formation was accelerated and difference between HK and LK cells was not significant. Denatured hemoglobin bound to the membrane protein was less in HK than in LK cells. During incubation with APH, osmotic fragility increased markedly in LK cells, while HK cells showed very little change. The amounts of total lipid, total and free cholesterol, glycolipid, phospholipid and fatty acids were essentially the same in both cell types. Fatty acid compositions showed very small differences. The membrane of HK cells thus appear to have greater protection against oxidative damage induced by APH, owing to the presence of excess GSH in HK cells. The capability of HK cells to withstand oxidative damage would not be due to differences in membrane lipid compositions.

Animals↗
PubMed1992

Immunohistochemical findings of juxtaglomerular cells on acute phase in two-kidney Goldblatt hypertensive rats and spontaneously hypertensive rats.

Juxtaglomerular (JG) cells on the acute phase in two-kidney Goldblatt hypertensive (2KGH) rats and spontaneously hypertensive rats (SHR) were examined immunohistochemically. JG cells in 2KGH rats and SHR were positively stained with anti-renin serum and anti-angiotensin II (A II) serum. In 2KGH rats, the number of renin and AII immunoreactive JG cells in the clipped kidneys increased throughout the observation period. The number of renin and AII immunoreactive JG cells in the unclipped kidneys was almost the same as that in control rats, although immunoreactivity of these cells was weak and they were small in size. These changes in the unclipped kidneys became obvious with the time course after operation. We did not see any changes in these cells in SHR. In 2KGH rats treated with captopril, the number of renin immunoreactive JG cells in the clipped kidneys increased, whereas that of AII immunoreactive JG cells in the bilateral kidney decreased. When captopril was administered to SHR, the number of renin immunoreactive JG cells in the bilateral kidney increased, whereas that of AII immunoreactive JG cells in the bilateral kidney decreased. These results suggested that the JG cell in the bilateral kidney was closely related to the development of hypertension in 2KGH rats, but not in SHR. The increase of renin immunoreactive JG cells in 2KGH rats and SHR treated with captopril was probably due to the removal of negative feedback inhibition of AII on JG cells.

Angiotensin II↗
PubMed1979

Lithium treatment in affective disorders from viewpoint of transcultural psychopharmacology: therapeutic plasma level.

The double-blind controlled studies on lithium carbonate therapy conducted in Japan have demonstrated that there are no significant correlations between clinical effectiveness and serum lithium level in manic patients as well as depressed patients and also that Japanese patients seem to require less lithium carbonate than their U.S. counterparts as an effective therapeutic dose, both in terms of mean maximum dose and serum level. Although any international comparison cannot be fully valid without using transculturally standardized assessment, the data of these studies were examined from the viewpoint of transcultural psychopharmacology and compared to the data from studies in U.S.A.

Bipolar Disorder↗
PubMed1979

Comparison of efficacy of amoxapine and imipramine in a multi-clinic double-blind study using the WHO schedule for a standard assessment of patients with depressive disorders.

A multi-clinic double-blind controlled study on amoxapine in comparison with imipramine, using the WHO Schedule for a Standard Assessment of Patients with Depressive Disorders, was performed and the data were analyzed with 111 patients. The assessment of severity of illness and overall improvement indicated clearly the superiority of the antidepressive effect of amoxapine to that of imipramine. The onset of antidepressive effect of amoxapine was clearly more rapid than that of imipramine, and in more than half of the patients in the amoxapine group the improvement was seen within four days following the drug administration. Amoxapine was superior to imipramine in terms of safety and usefulness. The side-effects due to amoxapine appeared less frequently and were less serious than with imipramine. The difference between amoxapine and imipramine was especially remarkable for hypotensive effect. The antidepressive effect of amoxaphine was superior to that of imipramine for almost all symptoms and signs. Amoxapine displayed an especially remarkable effect on psychomotor retardation, depressive feeling, anxiety and tension, somatic complaints and sleep disturbance.

Amoxapine↗