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Biomedical subjects

Y Koide

Publications and source records attributed to Y Koide.

At least 289 records · Page 16Linked to original sources
PubMed1979

Specificity of micro-leucocyte adherence inhibition test in patients with gastric cancer.

Specificity of micro-leucocyte adherence inhibition (LAI) test was studied in patients with gastric cancer. Because of the presence of nonspecific reactions, specificity appeared obscure unless interaction analysis was applied to the results of LAI tests. Application of interaction analysis revealed that only leucocytes from patients with gastric cancer showed specificity to gastric cancer antigen. Further technical improvement is required to eliminate nonspecific reactions which seem to be due to either leucocytes or tumor antigens.

Antigens, Neoplasm↗
PubMed1978

Studies of effector cell, antibody, and target cell interactions in natural cell-mediated cytotoxicity.

IgG antibodies bound to effector cells through Fc receptors were observed to determine the specificity of natural cell-mediated cytotoxicity (NCMC) against cultured target cells. When effector lymphocytes were isolated from the peripheral blood of most individuals, they already possessed natural antibodies specific for antigens on cultured cells. Since they lacked IgG antibodies specific for antigens on sheep red blood cell (SRBC) targets, natural cytotoxicity against SRBC was almost non-existent. Effector cells incubated in IgG anti-SRBC became specifically cytotoxic to SRBC. In the process, NCMC and antibody-dependent cell-mediated cytotoxicity was diminished, indicating that arming with anti-SRBC replaced natural antibodies and occupied Fc receptors on effector cells. Thus, treating effector cells with serum may result in increased or decreased cytotoxicity depending upon the specificity of antibodies within the serum. This type of modulation of NCMC occurs at the interaction between antibody Fc and Fc receptors and can explain blocking and unblocking.

Animals↗
PubMed1978

Specificities in natural cell-mediated cytotoxicity against lymphoblastoid cell lines. I. Selective inhibition by cross-competition.

The apparent nonselective effects of natural cell-mediated cytotoxicity tested directly on different lymphoblastoid cell targets were found to be quite specific in the cross-competition assay. The specificity was detected through inhibition of cytotoxicity by competitor cells sharing common specificities with the target cells. Cross-competition tests were performed employing eight lymphoblastoid lines including four T and four B cells. Selective inhibition observed between lymphoblastoid cell lines indicated that T and B cell lines were more antigenically similar within each group than between them. The target antigens that distinguish T cell from B cell lines have been tentatively called TA-T and TA-B.

B-Lymphocytes↗
PubMed1978

Augmentation of human natural cell-mediated cytotoxicity by a soluble factor. I. Production of N-cell-activating factor (NAF).

Natural cell-mediated cytotoxicity (NCMC) like immune T cell-mediated cytotoxicity and antibody production is regulated by a soluble factor released during co-culture of lymphocytes with mitomycin C-treated lymphoblastoid cell lines. This N-cell-activating factor (NAF) enhances the activity of effector N cells and increases natural cytotoxicity. There appears to be no restriction for compatibility at the A and B locus of the major human histocompatibility complex in the production or activity of the factor. NAF was observed in the supernatant as soon as 2 days after initiation of mixed culture with a peak of production at 5 days. A soluble factor produced and released by T cells in response to stimulation by other cells acts by enhancing cytotoxicity of effector cells in NCMC, demonstrating a T-N cell cooperation.

Animals↗
PubMed1978

Homovanillic acid in human cerebrospinal fluid.--Its concentration gradient and reduced levels in patients with epilepsy.

The homovanillic acid (HVA) concentrations in the lumbar cerebrospinal fluid (CSF) were determined in 38 epileptic and 39 control patients. The mean concentration of HVA was 23.9 ng/ml +/- 2.8 SEM for the epileptic group and 30.2 ng/ml +/- 2.1 SEM for the control group, respectively. Thus, HVA was significandly reduced in the patients with epilepsy compared with the controls. The mean HVA in the female patients was higher than in the male patients in both groups but this failed to reach statistical significance. There was no apparent relationship between the degree of reduced HVA concentration and other clinical indexes of the epilepsy (age, type and frequency of seizures, and anticonvulsant medication). For the determination of concentration gradient of HVA three fractions of the spinal CSF were obtained from 11 patients. A pronounced gradient of HVA concentration was found with a ratio of 1 : 1.46 : 1.97 for the first, second and third fractions. This suggests that a standardized conditions for collecting CSF should be employed to study HVA levels in humans.

Adult↗
PubMed1977

B cell antigens on effectors for natural cell-mediated cytotoxicity.

Cell suspensions enriched for N cells, the effector cell for human natural cell-mediated cytotoxicity, were observed to react strongly with a rabbit antiserum directed against an antigen associated with B cells. Treatment of the effector suspension with the antiserum resulted in inhibition of natural cell-mediated cytotoxicity. The blocking occurred, however, only with the intact antibody indicating that inhibition was caused through the formation of antigen-antibody complexes. The antiserum was then employed to arm natural effector cells to react specifically with B cell lines. Specific arming was achieved after the formation of antigen-antibody complexes was prevented by initially reacting the effector suspension with F(ab')2 of the anti-B cell antibody. This study also supports the identity of the subset of cells responsible for antibody-dependent and natural cell-mediated cytotoxicity and the similarity in their mechanisms.

Antigen-Antibody Complex↗
PubMed1977

Reconstitution of natural cell-mediated cytotoxicity with specific antibodies.

The apparent nonselective reactions of natural cell-mediated cytotoxicity (NCMC) are selective when tested by inhibition of cytotoxicity with competitor cells indicating a recognition of specificities by the effector cell. N cells that mediate this NCMC in humans have most of the characteristics of K cells that mediate antibody-dependent, cell-mediated cytotoxicity (ADCC) and possess Fc receptors. IgG antibodies attached loosely to N cells through their Fc region, form part of the class of lymphocytes with surface immunoglobulin. We hypothesized that ADCC and NCMS involved similar mechanisms but with the specificity of NCMC directed by the natural IgG antibodies already attached to N cells. Removal of the antibodies with trypsin and reconstitution with specific anti-HLA antibodies produced specific effector cells supporting the role of antibodies on N cells as directors of specificity in NCMC.

Antibody Specificity↗
PubMed1977

Determination of specificity in natural cell-mediated cytotoxicity by natural antibodies.

Natural cell-mediated cytotoxicity (NCMC) and antibody-dependent cell-mediated cytotoxicity (ADCC) appeared to involve similar cytotoxic mechanisms; effector N-cells killed target cells with IgG antibodies attached to the Fc receptor determining the specificity of the reaction. In NCMC the wide range of specificities detected by natural antibodies provided an effector system capable of recognizing numerous antigens on cultured target cells. When several target cells were tested concurrently, an apparent nonselective cytotoxicity resulted. The specificity of individual reactions against each of the target cells could be demonstrated by selective inhibition with competitor cells. The inhibition of cytotoxicity by competition and the effect of proteases on the effector cell for NCMC, but not for ADCC, initially suggested an antibody on the surface of the natural cytotoxic effector cell. This suggestion was supported by the loss of activity with treatments that removed immunoglobulins on the effector cell and by the recovery of reactivity with incubation of the cells in normal human serum. Absorption of the reconstituting serum with target cells resulted in loss of activity against that target cell, substantiating the role of natural antibodies.

Antibodies↗
PubMed1977

A transient increase in renal clearance of phosphate in response to continuous infusion of salmon calcitonin in rats.

The effects of intravenous carrier-free salmon calcitonin on renal clearances of phosphate, calcium, magnesium, sodium and potassium were studied in male parathyroidectomized (PTX) and intact rats. Both natural and synthetic hormone, when infused at constant rates (0.005 approximately 0.5 MRC U/hr), produced a rapid increase (peaking at about 60-90 min) in phosphate clearance. However, the maximal increase was transient in nature in PTX rats. In intact rats, the phosphaturic response was somewhat more pronounced and the decline after the peak was rather modest. When a large amount (4 MRC U) of calcitonin was given in divided doses, the second dose produced a lesser extent of phosphaturia in both intact and PTX rats. The phosphaturic response was accompanied by an increase in sodium and potassium clearances in PTX rats and by an increase in potassium clearance in intact rats. A fall in the apparent clearance values for calcium and magnesium occurred and was maintained throughout the infusion period of hormone in both intact and PTX rats. In conclusion, PTX rats respond to the intravenous administration of salmon calcitonin with a transient phosphaturic response which is accompanied by parallel diuresis of sodium and potassium along with sustained retention of calcium and magnesium by the kidney.

Animals↗
PubMed1976

Successful replacement of a thrombosed Björk-Shiley mitral valve prosthesis.

A case is presented in which 7 months after the first mitral valve replacement (MVR) the malfunction of a Björk-Shiley valve prosthesis was supposed and the thrombosed valve prosthesis was 2 months later successfully replaced. For the detection of the malfunction of the valve prosthesis echocardiography was especially useful.

Adult↗