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T Imir

Publications and source records attributed to T Imir.

At least 37 records · Page 2Linked to original sources
PubMed1995

The effect of omeprazole on human natural killer cell activity.

1. Omeprazole, an antiulcer drug, inhibits the gastric acid pump via blocking the parietal cell (H+ + K+)-ATPase. Omeprazole was also reported to have an inhibitory action on polymorphonuclear neutrophil activities. In the present study the potential effect of omeprazole on human natural killer cell (NK) activity was investigated. 2. Omeprazole decreased NK cytotoxic activity in a dose-dependent manner. 3. Degraded omeprazole showed a similar action. 4. In vitro NK inhibitory action of omeprazole and its acid-degraded form was observed at the concentrations equal and higher than 18 microM (micromolar). 5. NK inhibitory action of omeprazole was recovered to 75% by washing away of the agent. 6. Omeprazole decreased the conjugate formation of effector and target cells by 50% at the concentration of 288 microM

Dose-Response Relationship, Drug↗
PubMed1994

Decreased natural killer (NK) cell activity in zinc-deficient rats.

1. In the study, the effect of zinc deficiency, a natural killer (NK), and lipopolysaccharide (LPS) activated NK cell activity were investigated. 2. Rats were fed with zinc-deficient and normal diet for 3 weeks. 3. NK and LPS activated NK cell activity was 7.2 +/- 1.8%/10(6) cells (n = 10) and 9.5 +/- 4.3%/10(6) cells (n = 10), respectively, in the zinc deficient group. In the control group fed with normal diet, NK and LPS activated NK cell activity was 22.2 +/- 3.3%/10(6) cells (n = 10) and 32.5 +/- 3.5%/10(6) cells (n = 10), respectively. 4. Plasma zinc concentration was 131.7 +/- 8.8 micrograms/dl in the zinc-deficient group and 206 +/- 17.7 micrograms/dl in the control group. 5. The results suggest that decreased NK and LPS activated NK cell activity is associated with zinc deficiency.

Animals↗
PubMed1994

Natural cellular cytotoxicity in Behçet's disease.

This study evaluated the cytotoxic activity of natural killer cells in the active and inactive stages of Behçet's disease (BD) and attempted to develop a new explanation for its immunopathogenesis. Blood samples were taken from 16 BD patients and compared with 11 healthy individuals. The lymphocyte fraction was separated and diluted in RPMI-1640. Candida as a target cell (T) was mixed with lymphocytes (E) (effector cells) in ratios of T:E 1/5 and T:E 1/25. After the numbers of colonies were counted with controls, the anticandidal index (natural cytotoxicity) was calculated. Natural cytotoxicity relatively decreased in the active stage and increased in the inactive stage of BD. Although the difference between the mean value of natural cytotoxicity in the active stage and in the inactive stage was significant, the difference between the averages of active stage and the control group was insignificant. However, the difference between inactive stage and the control group was remarkable. The increase of the natural cytotoxic activity in the inactive period of the disease may play a role together with other immune mechanisms in the aetiopathogenesis of BD.

Adult↗
PubMed1994

The effect of inosiplex in subacute sclerosing panencephalitis: a clinical and laboratory study.

The immunomodulatory action of inosiplex, a drug frequently used in subacute sclerosing panencephalitis (SSPE), varies according to its dose and the subjects' immune status. In order to assess its effect in children and adolescents with SSPE, inosiplex (25-50 mg/kg/day) was given to 9 patients aged 7-17 years. Their clinical and immunologic status was evaluated before and after 2 months' treatment. Lymphocyte mitogenic response decreased in 6 cases. These patients were clinically stable or improving during this period. Changes in cytotoxicity (increased in 5/6 patients) and suppressor cell function (increased in 4/8 and decreased in 4/8) were not significant nor associated with any particular clinical course. Our results suggest that inosiplex at this dose is more likely to suppress lymphocyte proliferation in SSPE and this is not due to advancing disease. Longer follow-up of clinical and laboratory findings seems to be indicated in therapeutic trials in SSPE.

Adolescent↗
PubMed1993

Cimetidine as an immunomodulator in subacute sclerosing panencephalitis: a double blind, placebo-controlled study.

Cimetidine, an H2 histamine receptor antagonist, was used in subacute sclerosing panencephalitis patients for its immunomodulatory effect. Patients were randomly assigned to cimetidine (n = 7) and placebo (n = 7) groups. Neurologic disability index, lymphocyte functions, cerebrospinal fluid measles antibodies and IgG index were evaluated before and after 2 months of treatment. The neurologic disability index of the cimetidine group remained stable during the study period whereas the placebo group worsened. There were no differences in the immunologic test results, cerebrospinal fluid measles antibody titers and IgG index of the two groups. This study suggests that cimetidine may have a favorable effect on the clinical progression of subacute sclerosing panencephalitis. Further studies are required to investigate its mechanism of action and the associated changes in immune status.

Adolescent↗
PubMed1991

[Staphylococcal protein A, bacteriocin, DNase and lactamases of methicillin-resistant Staphylococcus].

231 Methicillin-Resistant Staphylococcus (MRS) and 76 Methicillin-Susceptible Staphylococcus (MSS) strains were investigated for Staphylococcal Protein A, bacteriocin, DNase and beta lactamase production properties. It was found that 73.6% of the strains of MRS were positive for protein A, 3.8% for bacteriocin, 76.2% for DNase and 84.4% for beta lactamase production. And it was found that 61.8% of MSS strains were positive for protein A, 11.8% for bacteriocin, 55.2% for DNase and 57.9% for beta lactamase production. Staphylococcal protein A, DNase and lactamase production. Staphylococcal protein A, DNase and lactamase production were found to be significantly higher in MRS strains than MSS strains and bacteriocin production was found to be higher in MSS strains than MRS strains according to Chi Square Test.

Bacteriocins↗
PubMed1991

[Antibiotic sensitivity tests of methicillin-resistant staphylococci].

In this study, 231 Methicillin-Resistant Staphylococcus (MRS) and 76 Methicillin-Susceptible Staphylococcus (MSS) strains were investigated. 23 antibiotics were tested by using Modified Kirby-Bauer Technique. The highest resistance ration in MRS strains were found for lincomycin, clindamycin and ampicillin with the ratios of 61.0%, 59.3%, and 56.2% respectively. And the lowest resistance ratios were measured for vancomycin, ciprofloxacin and ofloxacin 0.5%, 8.2%, 10.8% respectively. It was found that, resistance of MRS strains to 17 antibiotics were significantly higher than resistance of MSS strains, but not for sulbactam-ampicillin, cefoperazone, ceftriaxone, vancomycin, ciprofloxacin, ofloxacin and netilmicin.

Anti-Bacterial Agents↗
PubMed1989

The mechanisms involved in the activation of human natural killer cells by staphylococcal enterotoxin B.

The induction of enhanced natural cytotoxicity from human peripheral mononuclear cells by staphylococcal enterotoxin B (SEB) was examined. The activated killer cytotoxicity (AKC) was maximum at 16 hr with 1 mg/ml SEB. The precursor and effector cells of AKC were determined to be primarily CD5 negative, CD8 negative, CD16 positive cells. Monocytes and interleukin-1 played no role in the generation of AKC. However, a major role for interleukin-2 (IL-2) in AKC was shown by the inhibition of AKC when anti-IL-2 antibody or cyclosporin was added to the induction cultures. SEB rapidly induced the production of IL-2 from glass nonadherent cells by 6 hr and reached peak levels by 24 hr (162 U/ml). IL-2 induced by SEB in these induction cultures was preferentially produced by CD16 positive cells. Even though interferon-gamma (IFN-gamma) production was induced in these cultures, no role for IFN could be shown in SEB-induced AKC.

Antigens, Differentiation↗
PubMed1987

Peripheral blood mononuclear-cell interleukin-2 production, receptor generation and lymphokine-activated cytotoxicity in inflammatory bowel disease.

The interleukin-2 pathway is essential for the normal immune response to antigen stimulation; we have examined the possibility that this may underlie abnormal peripheral blood lymphocyte immunoregulatory function that has been observed in patients with inflammatory bowel disease. We studied 11 patients with Crohn's disease and 5 with ulcerative colitis, all with quiescent disease activity. Peripheral blood mononuclear cells were isolated from these patients and from healthy age- and sex-matched controls. Interleukin-2 production after mitogen and phorbol-myristate acetate stimulation was similar in both groups: 381 +/- 71 (mean +/- SE) U/ml by control cells and 451 +/- 70 by patient cells. Interleukin-2 receptor generation was also measured pre- and poststimulation by labeling with anti-Tac antibody. This was 10.45 +/- 1 and 69.95 +/- 3.85% for control cells and 11.41 +/- 1.38 and 60.9 +/- 4.25% for patients cells. Finally, we examined the response of these cells to interleukin-2 stimulation by generating cells with direct cytotoxicity to 51Cr-labeled Daudi-cell targets. Control cells caused 59.5 +/- 46% 51Cr release, whereas patient cells caused 50.8 +/- 5.18% release. None of the above results achieved statistical significance. We conclude that the peripheral blood interleukin-2 pathway is normal in inactive inflammatory bowel disease.

Cells, Cultured↗
PubMed1987

The relative resistance of lymphokine activated killer cells to suppression by prostaglandins and glucocorticoids.

The possibility that lymphokine-activated killer (LAK) cells versus spontaneous natural killer (NK) cells show relative resistance to the suppressive effects of the immunoregulatory molecules prostaglandin E2 (PGE2) and dexamethasone (DMO) was investigated. LAK cells were produced in vitro by the incubation of human peripheral mononuclear cells (PBMC) for three days in the presence of interleukin-2 (IL-2). Cytotoxicity of NK and LAK cells were measured by conventional 4 hour Cr51 release assays using K562 and Daudi target cells. LAK cells were relatively resistant to suppression by PGE2. For example, NK cytotoxicity was significantly suppressed by 10(-6) M PGE2. In contrast, LAK cells required a 30 to 100 higher concentration of PGE2 according to the target used to achieve similar suppression. Likewise, a differential resistance to DMO was seen. NK cells were significantly suppressed by 10(-3) M DMO while a 1000 fold higher concentration was needed for similar suppression of LAK cytotoxicity. Overall, the results show that LAK cells are relatively resistant to immunoregulatory suppressive factors.

Adult↗
PubMed1987

[Inhibition of natural killer and interleukin 2-activated natural killer cell cytotoxicity by monosaccharides and lectins].

NK cell receptors may be saturated and inhibited by a serial monosaccharides and lectins. Subsequently, NK cytotoxicity diminished in different ratios. Phosphorylated mannose and galactose were the major inhibitors. Also, the most of the lectins have NK cell inhibitory capacity. Normal lymphocyte may be activated by IL-2 within 72 hours culture. Those activated lymphocytes exerts high cytotoxicity and wide recognition capacity for the tumor targets. Besides, their receptors are less sensitive for the sugar inhibition. Lectins, have strong inhibition capacity even the lymphocytes are activated by IL-2.

Cells, Cultured↗
PubMed1986

Reversible inhibition of lymphokine-activated killer cell activity by lipoxygenase-pathway inhibitors.

Natural killer (NK) cells and lymphokine-activated killer (LAK) cells are anomalous cytotoxic cells which are potentially important in host defense against cancer. Several studies have demonstrated that natural killer (NK) cell activity can be suppressed by chemical inhibitors of the lipoxygenase pathway through inhibition of the production of leukotriene B4 (LTB4). The present study investigated the effects of the lipoxygenase inhibitors BW755C and nordihydroguaiaretic acid (NDGA) on NK and LAK cell activity. NK cell function of fresh peripheral blood mononuclear cells (PBMC) was determined via a standard chromium release assay employing K562 as the tumor target. The LAK cell activity of PBMC which had been stimulated with 10 IU of interleukin-2 for 72 hr was determined against the NK-resistant cell line Daudi. Both BW755C and NDGA inhibited NK and LAK cell function at a variety of concentrations. Indomethacin, a prostaglandin synthesis inhibitor, did not bring about an appreciable diminution in NK or LAK cell activity. Inhibition of NK and LAK cell activities by BW755C and NDGA could be reversed by washing the effector cell suspensions prior to the cytotoxic assay or by adding LTB4 (10(-11)-10(-8) M) directly to the effector:target suspensions. These data indicate that certain arachidonic acid oxidation products of the lipoxygenase pathway are essential for the function of LAK cells.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1986

Inert particles inhibit natural killer cell function in vitro.

Aqueous suspensions of inert particles were found to inhibit the baseline and interferon-enhanced natural killer (NK) cell activity of peripheral blood mononuclear cells (PBMC) and large granular lymphocytes (LGLs). This inhibition was induced with latex, silica, and Sephadex particles. The suppression of NK activity was not related to effector cell death as determined by trypan blue exclusion. The inhibition of NK cell function was more pronounced with prolonged incubation and could be partially reversed with monocyte depletion or the addition of indomethacin, a prostaglandin synthesis inhibitor, but not with the addition of the lipoxygenase inhibitors nordihydroguaiaretic acid and BW755C. Similarly, particle exposure inhibited the NK cell function of monocyte-depleted large granular lymphocytes with and without the add-back of glass adherent cells, implying that monocyte-independent NK suppressive mechanisms were also present. These data demonstrate that inert particles are immunosuppressive in vitro and can inhibit baseline and interferon-stimulated NK cell function of LGLs and PBMC through monocyte-dependent and independent pathways.

Humans↗
PubMed1985

Generation of natural killer cells and lymphokine-activated killer cells in human AB serum or fetal bovine serum.

Interleukin 2 (IL-2) can induce or enhance the cytotoxic activity of natural killer (NK) cells and lymphokine-activated killer (LAK) cells. The effects of fetal bovine serum (FBS) and human AB serum (HABS) on the IL-2-induced NK cell and LAK cell activities of large granular lymphocytes (LGL) were measured, respectively, against the NK-sensitive cell line K562 and the LAK-sensitive cell line Daudi. FBS and HABS were essentially equivalent in their effects on IL-2-dependent NK activity with prolonged culture. However, with prolonged incubation from 1 to 5 days of PBMC in the presence of IL-2, there was considerably less generation of LAK cell activity in FBS (Day 3: 5.3 +/- 3.4 LU/10(7) cells) compared to HABS (Day 3: 44.6 +/- 4.2 LU/10(7) cells) (P less than 0.05). These differences in IL-2-dependent LAK cell generation did not appear to be due to the lot of the FBS or to activating factors present in individual samples of HABS. Similarly, the suppressive effects of FBS could not be reversed with increasing concentrations of IL-2 ranging from 10 to 100 U/ml. Importantly, the presence of FBS in the cultures resulted in more cell death (15.9 +/- 5.6%) at 4 days of culture compared to HABS (1.8 +/- 1.0%) (P less than 0.05). These results suggest that FBS may inhibit generation of LAK effector cells, but not NK cells in cultures containing IL-2 and that the use of HABS as a culture supplement is preferable to FBS in studies of human LAK cell function.

Animals↗
PubMed1981

[Serum alpha-fetoprotein (AFP) levels in liver cirrhosis and viral hepatitis cases].

Serum alpha-fetoprotein (AFP) levels were investigated in 18 liver cirrhosis and in 114 viral hepatitis patients. The mean AFP levels were 9.3 ng/ml in cirrhosis patients and 46.6 ng/ml. in viral hepatitis patients. When viral hepatitis patients were classified according to hepatitis B antigen (HBsAg), no correlation could be detected between HBsAg positivity and AFP levels.

Hepatitis B↗
PubMed1978

IgA in blood and thoracic duct lymph: concentration and degree of polymerization.

Lymph fluid and serum samples from four mammalian species were studied forthe concentration and degree of polymerization of IgA. The results suggest that in the mouse, in the rat and in the dog circulating IgA represents only a small fraction of all IgA entering the blood stream from the lymph vessels. A majority of the input IgA of oligomeric type (13S, 11S and 9S) in these species is cleared rapidly. Monomeric IgA, and in the mouse and the dog the dimeric (9S) variety, dwell much longer in the blood; and because of this they form the majority of the circulating IgA. Blood concentration of IgA is high in man, a species whose blood seems to receive mostly monomeric IgA. It is much lower in the rat, mouse and dog, and in these species most of IgA entering the blood is probably oligomeric.

Animals↗
PubMed1977

Spontaneous, augmentable cell-mediated cytotoxicity with limited target cell specificity in human blood.

Nonadherent and nonphagocytic lymphoid cells from human peripheral blood became strongly cytotoxic against 51Cr-labeled chicken red blood cells and cells from an established human myeloma cell line when subjected to repeated cycles of washing in phosphate buffered saline or treated with trypsin or lecithinase. Prior to augmentation the effector cells pass nylon wool columns that remove practically all surface IgG-positive cells, but after augmentation they are retained in such columns. Augmentation does not make them phagocytic or adherent to plastic surfaces. Incubation at 37 degrees C of augmented cells prior to addition on the target cells restores the original nonaggressive state. Morphologically the cells making contact with the target cells are small or intermediate-sized mononuclear cells.

Animals↗