Search PubMed⌕ Search

Biomedical subjects

Y Kikuchi

Publications and source records attributed to Y Kikuchi.

At least 739 records · Page 41Linked to original sources
PubMed1986

A study on class II antigens involved in the T cell proliferative responses to PPD using cross-reacting monoclonal antibodies in human and murine system.

Two monoclonal antibodies (MoAb) 1E4 and ISCR3, which detect class II antigens across species barriers, were studied for their inhibitory effects on human and murine T cell proliferative responses to purified protein derivative of tuberculin (PPD). The 1E4 detected at least a polymorphic determinant on I-A molecules from mice carrying the H-2b haplotype, and the ISCR3 detected the Ia.7 determinant on I-E molecules. Nevertheless, both 1E4 and ISCR3 recognized monomorphic determinants on HLA-DR antigens (human I-E equivalent molecules), but not on HLA-DQ antigens (human I-A equivalent molecules). It was demonstrated that 1E4 significantly inhibited PPD-specific responses of T cells from Ib-bearing mice. In contrast, ISCR3 showed marginal effects on the responses of mice bearing Ia.7. However, in the human system both 1E4 and ISCR3 reduced proliferative responses to PPD. These results suggest that a functional difference exists between humans and mice in the I subregion products involved in the T cell proliferative responses to PPD.

Animals↗
PubMed1986

A nuclear gene of Saccharomyces cerevisiae needed for stable maintenance of plasmids.

We have isolated host mutants of Saccharomyces cerevisiae in which the 2 microns plasmid is poorly maintained. All the mutants tested constituted one complementation group, which was designated map1 (maintenance of plasmid). Minichromosomes carrying a chromosomal replication origin and a centromere were affected in the mutants. Two types of hybrid plasmids generated in vivo and in vitro appeared to compensate for the mutations and had DNA regions containing multiple ARS (autonomously replicating sequence) or a set of 2 microns inverted repeat sequences. These results suggested that poor maintenance of plasmids was due to low levels of replication, probably at the initiation of replication.

Cell Nucleus↗
PubMed1986

Ventilatory response to phasic contraction and passive movement in graded anesthesia.

The ventilatory response to electrically induced contraction (EIC) and passive movement (PM) of hindlimb muscles at different levels of anesthesia was studied in 11 chloralose-urethan anesthetized dogs with and without rhizotomy. The level of anesthesia was assessed by corneal reflexes and measurements of the ventilatory response to hypercapnia. Muscle contraction was induced by electrically stimulating the peripheral cut ends of the sciatic and femoral nerves for 4-5 min, and PM was induced manually at the same frequency and amplitude as during EIC. In spinal intact dogs (n = 7), initial rapid increases in minute ventilation (VE) during EIC and PM were found in both light and deep anesthesia. Further increases in VE above the initial rise were seen during EIC but not PM. The initial rapid increases in VE did not differ between the two anesthetic levels. The steady-state ventilatory response during EIC decreased as anesthesia deepened but did not do so during PM. Rhizotomy (n = 4) abolished the initial rapid increase in VE during EIC and PM and the steady-state VE response to PM at both anesthetic levels. These results suggest that the transitional ventilatory response is neurally mediated from the muscles and not affected by the level of general anesthesia. Additionally, the anesthesia-induced reduction of ventilatory response may be due to depression of responsiveness to CO2 rather than to the inspiratory motoneuron pathway.

Anesthesia, General↗
PubMed1986

Occurrence of premature chromosome condensation in mouse spermatogonia treated with busulfan.

Busulfan induction of premature chromosome condensation (PCC) was examined in mouse spermatogonia. Adult (C3H X SWV) F1 male mice were injected intraperitoneally with busulfan at 10 or 30 mg/kg of body weight and killed 18-72 h later. Polyploid-like mitoses were frequent (ca. 1/4 of all spermatogonial mitoses examined) in both the untreated and treated groups. Most of these were considered to have been derived from normal spermatogonia. In busulfan-treated mice, polyploid-like mitoses with PCC were seen. The frequency of PCC-containing mitoses increased with increasing dose and exposure time. A possible interpretation for PCC induction in mouse spermatogonia is discussed.

Animals↗
PubMed1986

Susceptibility of Bacteroides gingivalis to bactericidal activity of human serum.

Susceptibility of Bacteroides gingivalis strains to the complement-mediated bactericidal activity of human serum was examined under anaerobic conditions. Serum containing high concentrations of IgG antibody to B. gingivalis enhanced the bactericidal activity. No enhancement was found in serum which did not contain the specific antibody or in serum absorbed with intact cells. The sensitivity to the killing by pooled serum differed among B. gingivalis strains. Cells of B. gingivalis activated the pooled human serum complement not only through the classic pathway but also through an alternative pathway. It was found that the susceptibility of B. gingivalis to the bactericidal activity was classic-pathway-dependent.

Antibodies, Bacterial↗
PubMed1986

Nuclear bodies in human prostate with special reference to appearance rate.

The Nuclear Body Appearance Rate in seventeen human prostatic cases was statistically analyzed according to three lesion areas--the hyperplastic nodule, non-nodule and atrophic--in the secretory epithelium and basal cells. It was meaningfully high in the secretory epithelium of the hyperplastic nodule, but not in the other two lesion areas. There was no meaningful result in basal cells. Though there is a wide variety of reported data on the human prostate, particular care must be taken in analysis at the electron microscopic level, keeping in mind that even in a single specimen this organ has a notable variety of tissue changes. The Nuclear Body Appearance Rate reflects cellular hyperactivity although it does not have a specific known function at present.

Atrophy↗
PubMed1986

Adjuvant effects of tranexamic acid to chemotherapy in ovarian cancer patients with large amount of ascites.

Eleven patients with advanced ovarian carcinoma who had large quantities of ascites during the course of previous chemotherapy were tested with intraperitoneal injections of tranexamic acid, followed by combination chemotherapy. A 4-g dose of tranexamic acid was administered intraperitoneally every day for at least 2 weeks. Seven out of 11 patients (63.6%) showed changes from positive to negative in Papanicolaou smears of the ascitic fluid after treatment with tranexamic acid. A marked reduction of ascitic fluids was observed in 4 of 11 patients (36.4%). If 2 cases with partial reduction of ascites are included, the response rate improved to 54.5%. Median survival time after initiation of treatment with tranexamic acid was significantly longer in patients with good response to tranexamic acid than in patients with poor response. Proliferation of cells in cultures established from ovarian cancer tissue of a patient with good response to tranexamic acid was inhibited at all concentrations of tranexamic acid used in this study, in contrast to non-inhibition of similar cells cultured from a patient with poor response, at any concentration of tranexamic acid. These results suggest that treatment with tranexamic acid suppresses malignant cells in the ascites, followed by reduction of ascites themselves, and an improvement in the response rate to subsequent chemotherapy.

Adult↗
PubMed1986

Increased serum CA 125 levels during the first trimester of pregnancy.

An immunoradiometric assay for an ovarian tumor associated antigen (CA 125) has recently been developed. The CA 125 assay was reported to be fairly sensitive for ovarian cancer. However, elevated CA 125 levels were reportedly observed in 1% of healthy controls, 6% of patients with miscellaneous diseases and 29% of patients with non-gynecological cancer. Therefore, the specificity of the CA 125 assay must be evaluated before its wide clinical application. Furthermore, data on the CA 125 levels in pregnant women have not heretofore been reported. In the present study, CA 125 levels were determined in sera randomly obtained from normal, pregnant women at various weeks of pregnancy and in sera serially collected from women who achieved pregnancy after ovulation induction. When compared with the normal, non-pregnant state, CA 125 levels in pregnant women were significantly higher during the first trimester, but not during the second and third trimesters. Although CA 125 levels in women during the first trimester of pregnancy were significantly lower than those in patients with ovarian cancer, there was a considerable overlap between them. CA 125 levels were undetectable before pregnancy in all of the 8 patients who achieved pregnancy after ovulation induction. They rose during the first trimester of pregnancy in 7 of the 8 patients, and they decreased thereafter to undetectable levels by the end of the first trimester. The increased CA 125 level in the early pregnancy provides an important information for the clinical application of the CA 125 assay. Pregnancy should be ruled out when increased CA 125 levels are found in women during the childbearing years.

Antigens, Neoplasm↗
PubMed1986

Viscosity and order in erythrocyte membranes studied with nanosecond fluorometry.

The viscosity and the order in the interior of human erythrocyte membranes were investigated by the fluorescence depolarization technique in the nanosecond region with 1,6-diphenyl-1,3,5-hexatriene (DPH). After pulsed excitation with a polarized light, the fluorescence anisotropy ratio of DPH in membranes rapidly decreased and gave a final value (r infinity). The rate of initial decrease and the value of r infinity related to the viscosity in the interior of the membranes and a wobbling angle of DPH which reflects a size of range for the phospholipid motion relating to the order of membrane structure. For normal human erythrocyte membranes the viscosity and the wobbling angle were obtained to be 0.82 poise and 42 degrees, at 37 degrees C. Similar values were obtained for spectrin-free membranes. Hardened membranes by the cross-linking of the cytoskeletal proteins with glutaraldehyde showed a small wobbling angle of 37 degrees, but the viscosity of them was unchanged.

Blood Viscosity↗
PubMed1986

The role of I-region associated antigen (Ia)-bearing accessory cells in the generation of cytotoxic T cells in a subpopulation of thymocytes.

The roles of killer-helper factor (KHF) and accessory cells bearing I-region associated antigen (Ia) in the generation of cytotoxic T lymphocytes (CTL) were analyzed. Peanut agglutinin-binding (PNA+) thymocytes from C3H/HeN mice generated efficient CTL responses against 2,4,6-trinitrophenyl (TNP)-modified syngeneic spleen cells in the presence of cell-free supernatant (CFS) derived from purified protein derivatives (PPD)-stimulated Mycobacterium tuberculosis-primed BALB/c spleen cell culture (PPD-CFS). The KHF which is present in PPD-CFS devoid of the activities of IL-1 or IL-2 was required in conjunction with IL-2 for generation of CTL in PNA+ thymocytes. In contrast, PNA- thymocytes as well as spleen cells could generate CTL in the absence of helper factors. However, a significant CTL response against Ia-negative syngeneic tumor cells was not induced from either PNA+, PNA- thymocytes or spleen cells in the absence of Ia-positive accessory cells. Moreover, the treatment of spleen cells with relevant anti-Ia antiserum plus complement before TNP-modification abrogated the stimulatory capacity of TNP-spleen cells. In both cases, the addition of Ia-positive accessory cells restored the impaired capacity of TNP-modified stimulator cells. The addition of IL-1 to the culture of PNA- thymocytes or spleen cells stimulated with TNP-X5563 cells in the absence of accessory cells restored the CTL generation. In contrast, the addition of IL-1 to the culture of PNA+ thymocytes was ineffective. The role of Ia-positive accessory cells in the generation of CTL in a subpopulation of thymocytes is discussed.

Animals↗
PubMed1986

Inhibition of human ovarian cancer cell growth in vitro and in nude mice by prostaglandin D2.

In vitro and in vivo effects of prostaglandin D2 on human ovarian tumor growth were examined by using a cell line, designated HR, derived from ascites of a patient with serous cystadenocarcinoma of the ovary. The HR cell proliferation in vitro was dose dependently inhibited between concentrations of 0.1 and 4.0 micrograms of prostaglandin D2 per ml. From results of 51Cr release assays and trypan blue dye exclusion tests the inhibitory effect seemed to result from a direct cytotoxic effect by prostaglandin D2. All DNA, RNA, and protein syntheses by the HR cells were also inhibited in a dose-dependent manner with exposure time of 48 h to prostaglandin D2. When 5 X 10(5) HR cells were inoculated to nude mice, the 50% survival time of them in untreated groups was 52 days after inoculation. Although 4 mg of prostaglandin D2 per kg caused inhibition of the tumor growth, a significant prolongation of the survival time was not observed. On the other hand, the 50% survival time of nude mice treated with 12 mg of prostaglandin D2 per kg was significantly (P less than 0.05) prolonged to 67 days, in addition to a significant inhibition of the tumor growth.

Animals↗