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Biomedical subjects

K Kayashima

Publications and source records attributed to K Kayashima.

46 records · Page 3Linked to original sources
PubMed1982

Development of new hollow fiber membrane macromolecular filters.

Newly developed hollow fiber membrane filters made of ethylene-vinyl-alcohol designated as EVAL 2A, EVAL 4A, and EVAL 5A, were tested in vitro and applied clinically. EVAL 2A had the lowest molecular weight cut-off (30% rejection rate for 10(4) dalton dextran and 90% rejection rate for 10(5) dalton dextran); sieving coefficients (SC) of 0.78 for albumin, 0.59 for IgG, and almost 0 for IgM indicate its usefulness for separation of IgG from albumin when the recirculation flow on the filter was introduced. EVAL 4A and 5A showed higher cut-off levels (25% rejection of 10(5) dalton dextran and 80% rejection rate for 2 X 10(6) dalton dextran); SCs for albumin IgG, and IgM were 0.89, 0.83, and 0.24, respectively, indicating their usefulness in the separation of MMs of molecular size greater than IgG. IgM type cold agglutinin antibody (CAA), IC, and RF were effectively removed by these filters from CAA induced hemolytic anemia or rheumatoid vasculitis patients. Using recirculating flow to prevent filter plugging, one EVAL unit was found to be sufficient to treat 2-3 L plasma. These filter properties demonstrate the possible clinical application of EVAL filters for selective MM removal, when specific MM removal is indicated for the treatment of specific diseases.

Aged↗
PubMed1981

Chronic ambulatory liver support by membrane plasmapheresis with on-line detoxification.

Blood cellular elements and plasma protein losses are minimal for membrane plasmapheresis with on-line sorbent detoxification. Frequent (6/sk), chronic (3 mos), and long-term (8 hr) perfusions are possible for patients studied. It is recommended in deficiency states involving low protein, hypocoagulability or potential hormonal imbalances that aggressive medical management be applied. With regard to system performance, plasma filtration properties improved by the application of the closed plasma circuit and membranes with superior sieving and filtration properties. The effect of plasma solutes on filtration properties has been noted. In PBC patients the influence of total cholesterol concentration is particularly striking. Significant reduction of FFA and improvement of PMR were achieved in combination with bilirubin removal in liver failure patients, while bile acids (cholyglycine) levels were significantly reduced in 3 of PBC patients who expressed a subjective improvement of about 90% following 3 consecutive treatments. Four of 5 liver failure patients showed improved mental status with one patient surviving.

Adult↗
PubMed1980

Superoxide anion-generating activities of macrophages as studied by using cytochalasin E and lectins as synergistic stimulants for superoxide release.

Treatment of macrophages with cytochalasin E in combination with a lectin was found to stimulate the generation of superoxide anions (O2-) very efficiently. The macrophages stimulated with concanavalin A, phytohemagglutinin or wheat germ agglutinin released superoxide, but cells pretreated with cytochalasin E released much greater amounts of superoxide, without notable lag time, upon stimulation with the lectin. Wheat germ agglutinin was found to be the most efficient stimulant among the lectins tested. Superoxide generation in guinea pig macrophages was shown to be dependent largely on cytoplasmic glucose metabolism and to some extent on mitochondrial respiration, since the superoxide release was largely but not totally inhibited by 2-deoxyglucose and to a lesser extent by antimycin A or KCN. The method presented is sensitive and allows rapid assay of the superoxide-generating activity with only 1--5 X 10(5) macrophages for a single determination. In application of this technique, elevation of the superoxide-generating activity was shown with macrophages elicited by chemical inflammation or those obtained from mice after treatment with tubercle bacilli.

Animals↗
PubMed1979

Sensitive and rapid method for determination of superoxide-generating activity of blood monocytes and its use as a probe for monocyte function in cancer patients.

The superoxide anion-generating capacity of human blood monocytes was measured by a sensitive and rapid method established by taking advantage of the fact that the generation of superoxide anions by monocytes was markedly enhanced by the combined stimulation of the cells with cytochalasin-E and wheat germ agglutinin. The activity was expressed by the initial rate of cytochrome c reduction after the addition of wheat germ agglutinin. The rate obtained with normal human monocytes was 0.73 +/- 0.19 nmol/min/10(5) monocytes (mean +/- SD, n = 10). Because of its sensitivity, the method required only 10(5) monocytes and can be used to follow the monocyte function in various patients. Preliminary data obtained with 15 cases of advanced cancer patients (0.29 +/- 0.10 nmol/min/10(5) monocytes) suggested a possible decrease of the superoxide-generating activity, at least in some state of cancer patients. It appears that measurement of superoxide-generating activity will be meaningful to monitor monocyte function.

Adult↗
PubMed1978

Role of T lymphocytes in adjuvant arthritis. II. Different subpopulations of T lymphocytes functioning in the development of the disease.

The effects of treatments with cyclophosphamide (CY), hydrocortisone and anti-thymocyte sera (ATS) on the development of adjuvant arthritis (AA) were examined in WKA rats inoculated with wax D to induce AA. A single injection of 25 to 50 mg/kg of CY given 2 to 3 days before wax D inoculation caused severe arthritis with high incidence, whereas larger doses of CY were less efficient. Furthermore, the enhancing effect of CY pretreatment was abolished by passively transferred normal syngeneic thymocyreated with ATS and guinea pig C. On the basis of these results and the previous observations on the effect of adult thymectomy and low-dose irradiation, we concluded that this enhancing effect of CY pretreatment was caused by selective depletion of suppressor T lymphocytes. Pretreatment with 12.5 mg of hydrocortisone also caused severe arthritis. This enhancing effect of hydrocortisone could also be due to the elimination of those suppressor cells. In contrast, in vivo pretreatment with ATS showed striking inhibition on the development of AA, suggesting that ATS could eliminate T lymphocytes that were responsible for eliciting this disease. Thus it appears that at least two T cell subpopulations are involved in the development of AA, one is an ATS-sensitive T2 subpopulation that is effective for induction of AA and the other is a T1 subpopulation that regulates this disease process.

Animals↗
PubMed1976

Role of T lymphocytes in adjuvant arthritis. I. Evidence for the regulatory function of thymus-derived cells in the induction of the disease.

Rats of Wistar King Aptekman (WKA) were thymectomized at 4 weeks of age and injected with Mycobacterium tuberculosis wax D 6 weeks after the operation to induce adjuvant arthritis. The development of this disease was strikingly enhanced by this treatment. Further experiments showed that a 4- to 6-week interval between thymectomy and wax D injection was necessary to show the enhancing effect. Such enhancement by thymectomy was also shown in rats of another strain, Sprague-Dawley (SD). The enhancing effect of thymectomy was abolished when thymocytes of normal syngeneic rats were transferred to thymectomized rats 7 days before the wax D inoculation. Furthermore, severe arthritis was also produced in WKA rats that were pretreated with low dose (200 R) whole body irradiation, but not in those treated with higher doses (400 to 700 R). These results seem to indicate that the enhancing effect is brought about by selective depletion of a certain population of T lymphocytes. The population depleted may be thymus dependent, short-lived and radiosensitive, the properties of which agree whith those known for suppressor T lymphocytes. Thus, it appears that thymus-derived cells could normally exert a regulatory effect on the development of adjuvant arthritis which might render these rat strains relatively less susceptible to this disease.

Animals↗