PubMed Health⌕ Search

Biomedical subjects

V Barak

Publications and source records attributed to V Barak.

At least 127 records · Page 7Linked to original sources
PubMed1986

Parameters affecting the in vitro maturation of human monocytes to macrophages.

In vitro maturation of human monocytes to macrophages was characterized by morphological criteria, cell size and lysosomal enzymes activity. Purified populations of monocytes were maintained in culture at either adherent or nonadherent conditions and their maturation to macrophages was observed in both cases. The addition of external factors such as hydrocortisone and vitamin D3 inhibited monocyte maturation. In the absence of external factors, nonadherent monocytes were inhibited in their maturation for up to 10 days when plated at crowded cell concentrations. In addition, the presence of human serum in the culture media had a higher inhibitory activity than similar concentrations of fetal calf serum. Supernates from crowded macrophages were also inhibitory for monocyte maturation. We suggest the possibility that cell crowding, as well as soluble factors found in the serum and probably secreted by macrophages, participate in the regulation of monocyte development by inhibiting their maturation. Once released from this inhibitory signal or environment, the monocytes mature to macrophages.

Adolescent↗
PubMed1986

The effect of estradiol on human myelomonocytic cells. II. Mechanism of enhancing activity of colony formation.

Elevated proportions of monocytes have previously been found in the blood of healthy women during the ovulation period as well as in other conditions associated with increased blood estradiol (E2). This phenomenon was explained, in part, by an augmenting effect which physiological concentrations of E2 may have on the development of granulocyte-macrophage (GM) colonies derived from normal peripheral blood mononuclear cells. To analyze this effect, we tested possible alternatives for the interaction between E2, colony-stimulating factor (CSF) and GM colony progenitor cells. E2 was found not to interact synergistically with CSF, but pre-treatment of the progenitor cells with E2 resulted in higher numbers of colonies in response to CSF. Moreover, E2 did not induce higher secretion of CSF but treatment with anti-CSF antibodies abolished the enhancing effect of E2. Based on these results, we suggest that the augmenting effect of E2 on GM colony formation is mediated by inducing the colony precursor cells to be more responsive to CSF. These findings may help to elucidate some of the complex relationships between estrogens, immune responses and hemopoiesis.

Adult↗
PubMed1986

In vitro differentiation and establishment of cell lines derived from human myelomonocytic leukemia cells.

Primary cultures of cells derived from 13 patients with acute myelomonocytic leukemia (AMML) were studied with particular emphasis on in vitro proliferation, cell differentiation and the mode for establishment of cell lines. Using irradiated human macrophage monolayers to assist cell growth, we obtained four new cell lines of myelomonocytic origin. All the cell lines were characterized for cytochemical markers and response to phorbol esters (TPA), a differentiation inducing agent. In the absence of any inducing agent, spontaneous differentiation of blast cells into mature macrophages-like cells occurred in 8 out of the 13 primary cultures. Thus, maturation induction by agents such as TPA is not always required in order to obtain leukemic cell differentiation in vitro. The regulation of cell proliferation and differentiation by cellular interactions and by extrinsic soluble products is discussed in detail, in the light of these findings.

Cell Differentiation↗
PubMed1986

Detection of different interleukin-1 activities in human monocytes and monocytic cell lines.

Culture supernatants from normal human monocytes, monocyte hybrid cell lines, and myelomonoblastic cell lines were tested for human interleukin-1 (IL-1) activity. In the present study, we report the detection of IL-1 secreted by several cell lines of monocyte origin and compare their biological and biochemical characteristics. IL-1 activity was tested by the regular assay of phytohemagglutinin (PHA) response of mouse thymus cells. IL-1 was found to be constitutively secreted by U937 and the M20 cell lines, as well as by three of the monocyte hybrid cell lines. The activity was always augmented following dialysis and did not require the presence of serum for its secretion. We compared the IL-1 activity of the myelomonoblastic M20 and hybrid 1C4 cell lines to that of normal monocytes. We found differences in the kinetics of IL-1 secretion, the pattern of activity following dilution of concentrated supernatants, and augmentation of activity by various inducers. The differences described may be explained by concomitant secretion of IL-1 inhibitory factors, as well as the secretion of activities other than IL-1. Preliminary biochemical analysis showed that all three cell sources tested shared some species of molecules characterized by gel filtration and ion-exchange chromatography. However, some species of molecules expressing IL-1 activity were unique to the cell lines and were not found in normal monocytes.

Animals↗
PubMed1985

The effect of estradiol on human myelomonocytic cells. 1. Enhancement of colony formation.

Cyclic changes were observed in the content of blood monocytes during the menstrual cycle of normal women. Elevated blood monocytes were found during the ovulation period as well as in other conditions which are associated with increased blood estradiol (E2). To understand the possible association between E2 and monocytosis, we analysed the in vitro effect of E2 on the development of myelomonocytic colonies in culture. E2 in physiological concentrations was found to increase the number of colonies developed from peripheral blood mononuclear cells (PBM) of both females and males. The optimal concentration for the augmenting effect on males' PBM was lower than that for females. Mononuclear cells derived from cord blood, which yielded much higher numbers of colonies than adult PBM, also responded to the stimulatory effect of E2. Estrone and estriol were less effective than E2 in adult PBM. In contrast, progesterone, diethylstilbestrol and testosterone did not affect the number of colonies at the range of physiological concentrations tested. The anti-estrogen Tamoxifen did not inhibit the stimulatory effect of E2. The augmenting effect of E2 on monomyelocytic colony formation may explain at least in part the increase in blood monocyte content of women with high E2 as well as other phenomena of macrophage and granulocyte changes associated with the menstrual cycle.

Adult↗
PubMed1985

A new myelomonoblastic cell line (M20): analysis of properties, differentiation, and comparison with other established lines of similar origin.

A new myelomonoblastic cell line (M20) was established from the peripheral blood of a ten-year-old child with acute myeloblastic leukemia, using an improved method for supporting the initial stages of cell proliferation. The addition of irradiated macrophage monolayers to the proliferating cells appeared to overcome the deterioration of the primary cultures and enable them to continue proliferating until they became independent of this environment. The cell line that developed consisted of myeloblasts and promyelocytes characterized by light and scanning electron microscopy, cytochemistry, and enzymatic activities. The cells expressed Fc receptors and WT1 antigens but did not exhibit HLA-DR, HMA1, Epstein-Barr virus nuclear antigen, and surface Ig. The M20 cells produced colonies when cultured in semisolid medium and secreted lysozyme, prostaglandin E2, and interleukin 1. An attempt was also made to analyse the position of the M20 cells in the scheme of differentiation of the myelomonocytic lineage using different approaches. Treatment of the cells with 12-O-tetradecanoyl phorbol 13-acetate induced their adherence to plastic surfaces and partial maturation to macrophages as judged by morphological criteria, cytochemistry, and enzyme activities. However, comparison of the M20 cells to other well-established myelomonoblastic cell lines did not reveal any pattern suggesting a possible relationship between surface markers, cell function, and differentiation pathway of the various cell lines tested. Establishment of additional cell lines and identification of new markers may assist in defining the mechanisms involved in normal differentiation and malignant transformation of this cell lineage. In addition, such cell lines may also provide a tool for the quantitative recovery of a variety of monokines.

Animals↗
PubMed1984

Establishment of cell lines from somatic cell hybrids between human monocytes and mouse myeloma cells.

To study human monocyte functions, we attempted to immortalize human monocytes by producing somatic cell hybrids between such monocytes and the mouse myeloma cell line NSI. In this study we report the successful establishment of eight hybrid cell lines that have been grown in culture for more than a year, and some of them retained part of the human chromosome complement, as well as monocyte markers and activities. Karyotype analysis of these hybrid lines revealed that cells of seven out of eight of the lines contained one to 16 human chromosomes and in four of them, more than nine human chromosomes were observed. Several of the cell lines expressed monocytic markers and functions. Thus, in two of the hybrid lines nonspecific esterase could be demonstrated in 10 to 29% of the cells, and Fc receptors were demonstrated in three of the hybrid cell lines. Significant levels of human ferritin were detected in one of the lines, and two other cell lines secreted interleukin 1-like substance into the culture medium. These results encourage us to use human-mouse somatic cell hybridization as an approach for the establishment of human monocyte cell lines, which will preserve their functions and produce monocyte-derived factors.

Animals↗
PubMed1983

Constitutive secretion of interleukin 1 by human monocytes.

The constitutive and lipopolysaccharide (LPS)-induced secretion of interleukin 1 (IL 1) by cultured human monocytes and macrophages has been studied. Both freshly obtained monocytes and their culture-derived macrophages were induced by LPS to secrete similar amounts of IL 1. Such induction, however, was accompanied by the secretion of dialyzed inhibitory activity. Constitutive secretion of IL 1 was detected in concentrated supernatants of monocyte cultures. The factor obtained constitutively did not manifest significant inhibitory activity. A method is described for the recovery of IL 1-containing supernatants in serum- and other stimulant-free medium. The biological activities of the constitutively secreted IL 1 were similar to the LPS-induced activities. The constitutive secretion of IL 1 was not equally distributed in the entire monocyte population. We found that a small fraction of loosely adherent monocytes secreted higher amounts of IL 1 than the strongly adherent monocytes. However, the property of higher secretion of IL 1 was not stable and disappeared following monocyte cultivation. Thus, constitutive activity of IL 1 could be recovered either by concentrating the culture supernatants or by enriching a subset of monocytes with higher IL 1 activity.

Adolescent↗
PubMed1983

Selection and continuous growth of antigen-specific human T cells by antigen-treated monocytes.

Antigen-specific human T lymphocytes were selected by adsorption of peripheral blood mononuclear cells on monolayers of antigen-treated autologous monocytes. The enriched cell populations were propagated in interleukin 2-containing medium for 60-80 days. Their activity was tested by a proliferative response against the sensitizing antigen in the presence of irradiated autologous lymphocytes. Continuous cultures of enriched T cells responded specifically to three different protein antigens. The specific reactivity induced in vitro against at least one of the antigens was probably a primary response. In addition, the selected cultures were found to be enriched for OKT4-positive cells, in contrast to cultures of nonselected T cells which were enriched for OKT8-positive cells. These properties of the selected T lymphocyte populations were obtained following only one exposure to the sensitizing antigen, which was concomitant with adsorbance on monocytes and without cloning of the reactive cells. We suggest that specific adsorbance of lymphocytes on antigen-treated monocytes may result in a T cell population which combines both properties of antigen specificity and enrichment for the helper proliferative subset of T cells.

Adolescent↗
PubMed1981

Antigen presentation and regulatory functions of human monocytes in the in vitro response of lymphocytes against purified protein derivative of tuberculin (PPD).

Monocyte functions in the primary and secondary proliferative responses of human lymphocytes against purified protein derivative of tuberculin (PPD) have been studied. By applying the antigens either directly to the responding cells or on antigen-treated autologous monocytes, it was possible to distinguish between two different monocyte functions: antigen presentation and regulation. Their helper function in lymphocyte proliferation was found in cell-free supernatants of autologous and allogeneic monocytes and was expressed better in the secondary rather than in the primary responses. The antigen-presenting function of monocytes, however, was found to be more substantial in the primary response of lymphocytes. These results suggest that macrophage dependency of certain immune functions should be considered in regard to the various functions of macrophages, since at least quantitative differences for each of the macrophage functions were found in the primary and secondary proliferative responses.

Adolescent↗
PubMed1980

Characterization of human lymphocytes which proliferate "spontaneously" in vitro.

Human peripheral blood lymphocytes proliferate "spontaneously" in vitro following the reduction in the proportion of monocytes in culture. This cell proliferation, which takes place in the absence of any extrinsic antigenic stimulation, was found to reside in a small fraction of a non-T non-B cell population which was also Fc receptor-negative. Concomitant with the in vitro proliferation of the monocyte-depleted cells, an increase in the proportion of E rosette-forming cells was observed. Hence, in addition to the regulation of spontaneous proliferation of lymphocytes, it is suggested that monocytes may also be involved in the regulation of the proportion of T cells or in expression of the E-rosetting marker.

Bromodeoxyuridine↗
PubMed1979

In vitro proliferation of macrophage depleted human peripheral blood lymphocytes.

The incorporation of thymidine by normal human peripheral blood lymphocytes was tested in vitro following various culture conditions. A significant increase of thymidine uptake was observed in cultures depleted of plastic adherent, nylon wook adherent, or phagocytic cells. This proliferative activity occurred in the presence of various sera but was not due to a blastogenic response to a foreign protein, since it was also observed when autologous plasma was the only source of protein in the culture medium. The similarities and differences between this 'spontaneous' proliferative phenomenon and other blastogenic responses which are regulated by macrophages are discussed.

Adolescent↗
PubMedDate not supplied

Specific in vitro proliferative immune responses and lymphokine production in Ethiopian children with and without tuberculosis.

UNLABELLED: We investigated the profile of some in vitro parameters of cellular immune responses in non-HIV-infected Ethiopian children and young adults with and without tuberculosis (TB) as compared to healthy Ethiopian and non-Ethiopian controls. The in vitro proliferative responses of peripheral blood mononuclear cells (PBMC) to purified protein derivative (PPD) were determined in 15 Ethiopian children and young adults with TB, 12 healthy Ethiopian children who were contacts of TB patients, 20 Ethiopian children without contact with TB and ten non-Ethiopian controls. All TB patients and contacts had a positive Mantoux skin test. The PBMC proliferative response to PPD of the Ethiopian children with TB was significantly higher than that of the Ethiopian children without TB, while all Ethiopian children demonstrated stronger proliferative response as compared to non-Ethiopian healthy controls. Interleukin 2 (IL-2), interferon gamma (IFN-gamma), interleukin 4 (IL-4) and interleukin 6 (IL-6) were measured by ELISA assays performed on the supernatant of PPD-stimulated and non-stimulated PBMC cultures of seven Ethiopian children with TB, ten Ethiopian children without TB and eight non-Ethiopian controls. IFN-gamma and IL-4 were undetectable and IL-2 levels in unstimulated supernatants were low in all groups. PPD stimulation induced a significant rise in IL-2 levels in Ethiopians with TB as compared to all other groups. There was no increase above baseline in IL-6 levels in any group studied. CONCLUSIONS: Ethiopian children with TB exhibit a strong cellular immune response as expressed by Mantoux tests and lack of stimulation of IL-4 and IL-6 production. This pattern suggests a Th1 type effective cellular immune response to mycobacteria in a cohort of young Ethiopians with TB.

Adolescent↗
PubMedDate not supplied

The prognostic significance of increasing marker levels in metastatic breast cancer patients with clinically complete remission, partial remission or stable disease.

TPS, CA 15-3 and CEA were determined in metastatic breast cancer patients during treatment. After six months of follow-up the patients were divided into four groups according to the UICC criteria for treatment response. Forty-six patients with a more favorable prognosis (complete remission, partial remission or stable disease) were followed for an extended period. In 30 of the 46 patients at least one marker had increased at the end of the six-month period by at least 25% (TPS in 54%, CA 15-3 in 20%, CEA in 20%). All these 30 patients subsequently developed progression. The prognostic sensitivity was 83%, 30% and 30%, respectively, for TPS, CA 15-3 and CEA. The combination of TPS and CA 15-3 showed a sensitivity of 96%. The median lead time was about 8 months for TPS and CA 15-3, but less than 50% of the patients showed a lead time for CA 15-3 as compared to TPS. We conclude that TPS and CA 15-3 determinations are helpful for the prediction of progression during the follow-up of breast cancer patients.

Biomarkers, Tumor↗
PubMedDate not supplied

Symmetry of outcome after photorefractive keratectomy for myopia.

The aim of this study was to find out whether the outcome of excimer laser photorefractive keratectomy (PRK) in the second eye can be predicted from the results of the first, and to determine whether we should modify our therapeutic approach to the second eye according to the results of the first. Bilateral PRK was performed in 73 patients using the Summit Technology excimer laser. All patients included in this study had a follow-up of at least 12 months in both eyes. The change of refraction and the haze of the two eyes were compared. Sixty percent of patients had a difference in refraction between the two eyes smaller than 0.50 diopters (D), and 75% had a difference smaller than 1.00 D. The degree of symmetry in response to treatment was greater in patients with a preoperative spherical equivalent refraction of less than -6.00 D. Most patients had a similar degree of haze in both eyes. The results of our study demonstrate that a considerable degree of symmetry in the outcome of surgery exists between the two eyes of the same patient undergoing PRK, especially in low to moderate myopia.

Adolescent↗
PubMedDate not supplied

Cytokines in experimental autoimmune vasculitis: evidence for a Th2 type response.

OBJECTIVE: To investigate the pathogenic role of cytokines in the development of experimental autoimmune vasculitis. METHODS: BALB/c mice were immunized with human IgG-ANCA from a patient with WG. Control mice were immunized with normal human IgG. Levels of mouse IgG-ANCA and other autoantibodies were determined. The mice lungs and kidneys were examined for the development of vasculitis. Levels of interleukin-1 beta (IL-1 beta), IL-2, IL-4, IL-6, interferon gamma (IFN gamma) and TNF alpha were determined by ELISA two weeks after immunization of the mice. RESULTS: Mice immunized with human IgG-ANCA developed anti-human IgG-ANCA (= Ab2) and anti-anti-human IgG-ANCA (mouse IgG-ANCA = Ab3), while the controls did not develop these antibodies. The mice that were immunized with human IgG-ANCA developed perivascular mononuclear cell infiltrates in the lungs, suggesting vasculitis. Levels of IL-4, IL-6 and TNF alpha but not IL-1 beta, IL-2 and IFN gamma were significantly elevated in the mice 2 weeks after immunization with IgG-ANCA. CONCLUSION: Our results suggest a pathogenic role for IL-4, IL-6 and TNF alpha in the initiation phase of autoimmune vasculitis. This suggests that a Th2 type immune response is responsible for the initiation of experimental autoimmune lung vasculitis, similar to Wegener's granulomatosis in humans.

Animals↗
PubMedDate not supplied

Prognostic value of CYFRA 21-1, TPS and CEA in different histologic types of non-small cell lung cancer.

The prognostic value of the tumor markers CYFRA 21-1, tissue polypeptide specific antigen (TPS) and carcinoembryonic antigen (CEA) was investigated in three histologic subtypes of non-small cell lung cancer. Pretreatment serum marker levels were measured in 38 patients with adenocarcinoma (AC), in 43 patients with squamous cell carcinoma (SQC) and in 35 patients with large cell carcinoma (LCC). Univariate analysis in AC showed significant lower survival of patients with elevated levels of TPS, CYFRA 21-1 and CEA. In LCC, elevated levels of TPS and CEA were found to predict lower survival, while in SQC--only TPS was a predictor. A multivariate analysis of survival identified CEA (Relative Risk-5.5; p = 0.004), CYFRA 21-1 (RR-3.4; p = 0.008) and TPS (RR-3.0; p = 0.02) as independent prognostic factors in AC. In SQC, only TPS (RR-2.3; p = 0.03) was such a factor whereas in LC--none of the markers studied retained statistical significance. Thereafter, the combinations of the two strongest prognostic factors in the AC group--CEA and CYFRA 21-1 were explored to divide this group into subsets with different prognosis. In cases where both markers were positive, the relative risk of death was 10.5 times higher as compared to cases where both markers were negative (p = 0.002).

Adenocarcinoma↗