Biomedical subjects
Publications and source records attributed to T Takeuchi.
Enantiomeric separation of amino acids on an L-proline-bonded phase was examined in micro high-performance liquid chromatography. Gradient separation of seven pairs of racemic dansyl amino acids was achieved by connecting chiral and hydrophobic columns in series.
A new family of asymmetric thiol-disulfide exchange reagents, the dinitrophenyl alkyl disulfides (DNPSSR), was used to modify rat liver phenylalanine hydroxylase. The results indicate that the enzyme has two different types of reactive sulfhydryl (SH) residues per subunit. One SH residue was modified selectively by a DNPSSR having a neutral and hydrophilic alkyl group, and this modification was accompanied by appreciable activation of enzyme; the other SH residue was modified only by an anionic DNPSSR, and this modification did not result in activation. The catalytic properties of phenylalanine hydroxylase activated by DNPSSR were similar to those of the N-ethylmaleimide- (NEM-) modified enzyme, but the process of activation by DNPSSR was quite different from modification with NEM. An analysis of the reaction kinetics of the modification and of catalysis by the modified enzyme suggests that DNPSSR modification causes a change in the subunit interaction leading to a loss of the negative cooperativity normally seen with phenylalanine hydroxylase.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
It has been demonstrated that the T4+2H4+ subset functioned as a suppressor inducer cell, whereas the reciprocal T4+2H4- subset provided help for B cell Ig production. In the present studies, a series of monoclonal antibodies to cell surface structures expressed on these subsets of cells were examined for their effects on the proliferative and immunoregulatory functions generated in AMLR. We demonstrated that anti-T4 antibody preferentially inhibited the proliferative response of the T4+2H4+ but not T4+2H4- cells against self-MHC antigens. In contrast, anti-T3 and anti-Ia antibodies inhibited the response of both subsets of cells. This subset preference of anti-T4 antibody was not attributable to either the isolation procedures used or a shift in the kinetics of proliferation to autologous self-MHC antigens. Moreover, both IL 2 production and the immunoregulatory function of the T4+2H4+ subset was profoundly inhibited by anti-T4 antibody, whereas the T4+2H4- subset was minimally influenced. In the absence of Ia molecules, T4+2H4+ but not T4+2H4- cell proliferation was inhibited with anti-T4 antibody. Together, these results suggest that the T4 molecule plays a distinct functional role in the differential triggering of subsets of T4+ cells.
The separation of large oligodeoxyribonucleotides, synthesized chemically and subsequently deblocked, was carried out by reversed-phase ion-pair chromatography (RP-IPC) with a linear gradient of acetonitrile concentration. It was found that tetrabutylammonium phosphate is suitable as an ion-pairing reagent and produces a linear relationship between the base numbers of the samples and their elution volumes. It was also verified that various factors effective in reversed-phase chromatography, such as temperature, end-capping of the columns, differences in the type of C18 alkylating reagents and in the base silica, and the pore size of the base silica have little effect on the resulting separation by RP-IPC.
Herbimycin A specifically increased the level of fibronectin mRNA in Rous sarcoma virus-infected rat kidney cells, and the time course of fibronectin expression was found to be closely related to that of morphological change induced by herbimycin A.
Spergualin exhibited a strong antitumor effect against L1210(IMC), a tumor cell line which has been maintained in BALB/c X DBA/2 F1 (hereafter called CD2F1) mice in the Institute of Microbial Chemistry. Mice inoculated i.p. with 10(5) cells of L1210(IMC) survived more than 60 days by daily i.p. administration of spergualin for 9 days at 5 mg/kg/day, which was started 1 day after the tumor inoculation. These cured mice rejected a second inoculation of 10(6) cells of L1210(IMC), but they did not reject the inoculation of 10(2) P388 cells. In Winn's tumor neutralization assay and in the 51Cr release assay, the T-cell fraction prepared from the spleens of the cured mice had higher cytotoxic activity against L1210(IMC) than whole spleen cells. The cytotoxic activity of spleen cells was diminished by treatment with anti-Thy-1.2 or anti-Lyt-2.1 antibody and complement. Therefore, the effector cells involved in the immunological rejection should be regarded as cytotoxic T-lymphocytes. The cytotoxic activity of these T-lymphocytes was measured during and after the spergualin administration for 9 days, and high activity was observed from 1 day after the final spergualin administration. The antitumor effect of spergualin against L1210(IMC) was much lower in T-cell-deficient athymic mice. These results suggest that cytotoxic T-lymphocytes are involved in the antitumor action of spergualin against L1210(IMC) in vivo.
Albino mutation in animals blocks pigmentation owing to a deficiency in tyrosinase, although it does not affect the differentiation of colorless melanocytes from the neural crest. In the albino Japanese quail (al, sex-linked), it was demonstrated that morphologically normal melanocytes differentiated from neural crest cells in culture and that these cells contained unmelanized melanosomes as expected for the mutant cells. The mutant melanocytes, however, were shown to exhibit tyrosinase activity in the Golgi-endoplasmic reticulum-lysosome region and in the Golgi vesicles. Our results seem to indicate that the mutation at the al locus affects the transport of tyrosinase from the Golgi area to melanosomes.
In this study, we have investigated the cellular and molecular basis for immunoregulatory function of T4+ cells after autologous mixed lymphocyte reaction (AMLR) activation. We demonstrated that the T4+ 2H4+ subset but not the T4+2H4- subset can proliferate maximally in response to autologous non-T cells. T4+ cells activated by AMLR exerted suppressor activity on pokeweed mitogen-driven IgG synthesis of autologous peripheral blood lymphocytes. The suppressor activity by AMLR-activated T4+ cells required the presence of fresh T8+ cells in the secondary culture, indicating that AMLR-activated T4+ cells functioned as a suppressor inducer rather than as a suppressor effector population. Following activation of T4+ cells in AMLR, it is the T4+2H4+ subset which induces suppression through the T8 population. Moreover, the treatment of AMLR-activated T4+2H4+ cells with anti-2H4 antibody, but not other antibodies, resulted in the abolishment of suppressor inducer function of such cells, suggesting that the 2H4 molecule itself may be involved in the suppressor inducer function. The 2H4 antigen on such cells was shown to be comprised of 220-kDa and 200-kDa glycoproteins. These results support the notion that the AMLR may play an important role in generating suppressor inducer signals and in down-regulating the immune response following self major histocompatibility complex recognition. More importantly, the present studies indicate that the 2H4 antigen on T4 cells serves not only as a phenotypic marker of suppressor inducer cells, but may have a functionally important role itself inducing suppression.
Two infants with malignant histiocytosis, as diagnosed by morphological and cytochemical examinations of malignant cells infiltrating pleural effusion, skin, and bone marrow, are described. Surface marker analysis of the malignant cells with monoclonal antibodies showed these cells to express markers of T-lymphocytes and HLA-DR antigen, but not those of B-lymphocytes, granulocytes, or monocytes. These immunological findings demonstrated that the neoplastic cells in malignant histiocytosis of infancy may be of T-cell origin, rather than histiocytic or monocytic origin.
The effectiveness of adjuvant chemotherapy in transitional cell carcinoma of the bladder (T1/G3 and greater than or equal to T2) and the upper urinary tract were evaluated. Among a group of 136 patients (male 107, female 29) with such tumors, complete tumor resection was possible in 108, in whom duration of survival and disease-free interval with or without chemotherapy were compared. The combination of antineoplastic agents used was changed from 5-fluorouracil (5-FU) + vincristine (VCR) + bleomycin (BLM) or peplomycin (PEP) + mitomycin C (MMC) or 5-FU + VCR + PEP + cyclophosphamide (CPM) + adriamycin (ADM) to CPM + ADM + cis-platinum (DDP) or methotrexate (MTX) + vinblastine (VBL) + ADM + DDP. Of the 59 patients in the chemotherapy group, 23 (39%) had side effects due to the treatment; however, fever and gastrointestinal symptoms were the chief adverse effects and were well tolerated. The 5-year survival rate and mean disease-free interval in the chemotherapy group were 76.3% and 24.6+ months, respectively, in bladder cancer patients, and 78.2% and 25.8+ months in those with upper urinary tract tumors. However, in the non-chemotherapy group (n = 49) the corresponding values were 62.7% and 21.1+ months in patients with bladder cancer and 67.3% and 42.0+ months in those with upper urinary tract tumor. There was a statistically significant difference (P less than 0.05) in the disease-free intervals of the two treatment groups for bladder cancer patients. Recurrence, regardless of time, was observed in 25% of chemotherapy cases and in 65% of non-chemotherapy cases, and this difference was also statistically significant (P less than 0.001). These results suggest that adjuvant chemotherapy for uroepithelial transitional cell carcinoma may be effective in extending survival and significant by protracting the disease-free period, especially in cases of advanced bladder cancer.
It is suggested that autologous mixed lymphocyte reaction (AMLR) may play an important role in generating suppressor inducer signals and in down-regulating the immune response following self-major histocompatibility recognition. In the present study, monoclonal antibodies directed at cell surface structures on T4+ cells activated in AMLR were used to define the molecules important in the generation of the suppressor inducer signal. The density of a 200/220-kDa structure, termed 2H4, increased on T4 cells during activation in AMLR and furthermore a strong correlation was observed between the generated suppressor inducer activity of such cells and the density of the 2H4 antigen. More importantly, we showed that treatment of AMLR activated T4 cells with anti-2H4 but not anti-T3 or T4 antibody abolished the suppressor inducer function of these cells. These results suggest that the 2H4 molecule but not the T3-receptor complex plays an important role in generating suppressor inducer signals in the AMLR system.
REM sleep latency observed in 61 mentally retarded infants (4-13 months of age) was studied throughout nocturnal sleep. Mentally retarded infants revealed a J distribution of short (less than 8 min) and long (more than 8 min) REM sleep latencies. This feature of distribution was similar to that obtained by other authors from normal infants under 3 months of age. REM sleep latency did not depend on the duration of prior wakefulness. Long REM sleep latencies were no more often preceded by long episodes of wakefulness than were short REM sleep latencies. No correlation was found between REM sleep latency and age, developmental quotient or daytime clinical EEG abnormalities.
Skin potential responses (SPRs) of 89 mentally retarded children were studied during their nocturnal sleep. Forty-three out of the 89 subjects showed more SPRs (type A) during NREM sleep than in REM sleep. The opposite was observed in 10 cases (type C), and 4 had evenly distributed SPRs during both sleep phases (type B). The remaining 32 subjects had mixed types AB (n = 19), AC (n = 6) or BC (n = 7). Types B and C (including the mixed type) were observed more frequently for subjects with low developmental quotient (DQ) and abnormal clinical EEGs than for those with high DQ and normal clinical EEGs. Since it has been well established that normal subjects of 3 months and over exhibit exclusively type A, SPRs may be used as an additional tool for the diagnostic assessment of mental retardation in early infancy.
Using the cornea of macaque monkey, we demonstrated the relationship between cell density and growth of endothelial cells in vitro. Corneal endothelial cells in a cell sheet grow most actively in regions with cell density of 1000 to 1800 cells/mm2, in explant cultures and cell sheets and in concentrated inocula dissociated cells. Cell morphology was well sustained in these cultures. Cells cultured at a higher cell density retained their potential to proliferate actively, showing clear contrast to cells cultured at a density lower than 200 cells/mm2. When dissociated cells were cultured at a low density and maintained for more than 4 weeks, they gradually lost their growth potential, altered into polymorphonuclear giant cells and eventually dedifferentiated. In addition, cells with no contact with each other did not express growth potential. Density dependent growth was confirmed by measuring the mitotic index against the cell density per square mm from the center to the peripheral regions in cultured explants. It is concluded that the growth pattern of corneal endothelial cells is closely related to cell density, and that growth of these cells might be regulated through intercellular communications.
Explore the source record for details and available documents.
A rare case of primary adenocarcinoma of the seminal vesicle is examined in an 87-year-old Japanese man. Neoplastic cells, especially poorly differentiated cells, showed a positive reaction with periodic acid-Schiff reagent and anti-carcinoembryonic antigen. Neoplastic cells invaded the bladder wall but not the prostate. No other primary tumor was demonstrated.