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Human Leukocytes (human + leukocyte)
Terms modified by Human Leukocytes Selected AbstractsNew insights into the regulation of iron homeostasisEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 5 2006R. Deicher Abstract Hepcidin evolves as a potent hepatocyte-derived regulator of the body's iron distribution piloting the flow of iron via, and directly binding, to the cellular iron exporter ferroportin. The hepcidin-ferroportin axis dominates the iron egress from all cellular compartments that are critical to iron homeostasis, namely placental syncytiotrophoblasts, duodenal enterocytes, hepatocytes and macrophages of the reticuloendothelial system. The gene that encodes hepcidin expression (HAMP) is subject to regulation by proinflammatory cytokines, such as IL-6 and IL-1; excessive hepcidin production explains the relative deficiency of iron during inflammatory states, eventually resulting in the anaemia of inflammation. The haemochromatosis genes HFE (the human leukocyte antigen-related gene), TfR2 (the transferrin receptor-2 gene) and HJV (the haemojuvelin gene) potentially facilitate the transcription of HAMP. Disruption of each of the four genes leads to a diminished hepatic release of hepcidin consistent with both a dominant role of hepcidin in hereditary haemochromatosis and an upstream regulatory role of HFE, TfR2 and HJV on HAMP expression. The engineered generation of hepcidin agonists, mimetics or antagonists could largely broaden current therapeutic strategies to redirect the flow of iron. [source] Supernatants of Pseudomonas aeruginosa induce the Pseudomonas -specific antibiotic elafin in human keratinocytesEXPERIMENTAL DERMATOLOGY, Issue 4 2003Ulf Meyer-Hoffert Abstract: Elafin is a skin-derived serine-protease inhibitor. It is thought to be important to prevent human leukocyte elastase-mediated tissue damage and might play an important role in maintaining the integrity of the human epidermis. Recent studies have provided evidence for an antimicrobial activity of elafin against P. aeruginosa. As gram-negative infections typically occur in barrier-disrupted skin we were interested to determine whether supernatants of the gram-negative bacteria P. aeruginosa and Escherichia coli were capable of inducing elafin expression. Supernatants of various P. aeruginosa strains stimulated elafin mRNA-expression and protein release, whereas supernatants of E. coli did not induce elafin expression. In non-differentiated cells the relative increase of elafin mRNA was much higher (100-fold) than in differentiated cells (sixfold), although the latter exhibited higher constitutive mRNA-expression (150-fold). However, concentrations of secreted elafin were similar in differentiated and non-differentiated cells after stimulation. We could not confirm a bactericidal effect against P. aeruginosa as described previously but observed that its growth was inhibited as demonstrated for different strains in liquid cultures. Growth of E. coli was not affected by elafin. In conclusion, the data presented in this paper suggest that elafin represents an innate immune response factor induced by secreted products of P. aeruginosa. Besides its elastase inhibitory potency elafin is an antimicrobial agent against P. aeruginosa. [source] Histopathological bone marrow changes after reduced-intensity hematopoietic stem cell transplantation for follicular lymphoma involving bone marrowPATHOLOGY INTERNATIONAL, Issue 6 2007Takashi Maeda Allogeneic stem cell transplantation (allo-SCT) is used as curative therapy for malignant lymphoma, and reduced-intensity hematopoietic stem cell transplantation (RIST) is sometimes performed to avoid the toxicity and mortality associated with myeloablative allo-SCT. RIST is generally preferred for elderly patients with malignant lymphoma. A 62-year-old woman with follicular lymphoma (FL) involving bone marrow (BM) suffered relapse after autologous SCT. RIST was performed; cells were from an unrelated, fully human leukocyte antigen-matched donor. To study the hematopoietic reconstitution, BM biopsy specimens that were obtained at different times after RIST, were evaluated. Engraftment of donor cells was observed on days 19 and 48 after RIST, and residual FL in BM had completely disappeared by day 73 after RIST. This is the first report to document histological BM regeneration after RIST and disappearance of FL involving the BM. [source] Enhanced levels of cow's milk antibodies in infancy in children who develop type 1 diabetes later in childhoodPEDIATRIC DIABETES, Issue 5 2008Kristiina Luopajärvi Background:, Early exposure to cow's milk (CM) proteins have been implicated in the pathogenesis of type 1 diabetes (T1D). Objective:, We analyzed the development of the humoral immune response to dietary CM proteins in early childhood and its relation to later T1D. Subjects and methods:, We studied a subgroup of 94 children randomized to be weaned to a CM-based infant formula in the trial to reduce insulin-dependent diabetes mellitus in the genetically at risk (TRIGR) pilot study. All subjects carried human leukocyte antigen-conferred T1D susceptibility and had an affected first-degree relative. After 7 years of follow-up, 8 subjects had progressed to T1D, 15 had at least one disease-associated autoantibody, and 71 remained autoantibody negative (controls). Immunoglobulin (Ig) G and IgA class antibodies to whole CM formula, beta-lactoglobulin (BLG), bovine serum albumin, and alpha-casein and IgG antibodies to bovine insulin (BI) were measured with enzyme-linked immunosorbent assays from sequential samples. Results:, The children with later T1D showed increased IgG levels to BLG from 3 to 18 months of age (p = 0.028) and enhanced IgA levels to CM formula at the age of 9 months (p = 0.022) compared with controls. In the children with an affected father or sibling, IgG antibodies to BI were higher in autoantibody-positive subjects than in autoantibody-negative subjects at 18 months of age (p = 0.022). Conclusion:, An enhanced humoral immune response to various CM proteins in infancy is seen in a subgroup of those children who later progress to T1D. Accordingly, a dysregulated immune response to oral antigens is an early event in the pathogenesis of T1D. [source] Hepatitis B immunoglobulin in combination with lamivudine for prevention of hepatitis B virus reactivation in children undergoing bone marrow transplantationPEDIATRIC TRANSPLANTATION, Issue 8 2006Betul Tavil Abstract:, There is little information in literature about the use of hepatitis B immunoglobulin (HBIg) in recipients of bone marrow transplantation (BMT). Here, we report two children who received IV HBIg (Hepatect-CP) and lamivudine treatment during BMT course for either patient or donor hepatitis B virus (HBV) viremia. A four-year-old girl underwent a fully human leukocyte antigen-matched allogeneic BMT for thalassemia major from her mother positive for hepatitis B surface antigen (HBsAg). A 12-yr-old boy with chronic myeloid leukemia, positive for HBsAg and HBV-DNA received a fully HLA-matched allogeneic BMT from his sister in the first chronic phase of the disease. HBIg was successfully used in both cases to prevent HBV reactivation of the recipients. The results of our observations are encouraging and we suggest that HBIg in combination with lamivudine may be used in such cases especially in post-transplant early period to prevent HBV reactivation. [source] Adoptive immunotherapy with allogeneic Epstein,Barr virus (EBV)-specific cytotoxic T-lymphocytes for recurrent, EBV-positive Hodgkin diseaseCANCER, Issue 9 2004Kenneth G. Lucas M.D. Abstract BACKGROUND It has been shown that adoptive immunotherapy with Epstein,Barr virus (EBV)-specific cytotoxic T-lymphocytes (CTL) is effective for the treatment of EBV-induced lymphoproliferative disease in stem cell transplantation recipients and organ transplantation recipients. The role of EBV CTL in other tumors for which this virus has been implicated in pathogenesis, such as EBV-positive Hodgkin disease (HD), has not been demonstrated clearly. METHODS To investigate the antitumor effects and toxicity of allogeneic EBV CTL in EBV-positive HD, the authors initiated a pilot trial in which EBV CTL were cultured from allogeneic, partially human leukocyte antigen-matched donors and were infused into patients who had therapy-refractory disease. The first cohort of 3 patients (Cohort I) received 3 separate infusions of EBV CTL (5.0 × 106 EBV CTL/kg per dose), and the second cohort (Cohort II) received 30 mg/m2 per day of fludarabine for 3 days followed by a single CTL infusion (1.5 × 107 EBV CTL/kg). RESULTS All three patients in Cohort I had decreases in measurable disease after EBV CTL infusions, and one of those patients was without evidence of disease 22 months after infusion. Two of 3 patients in Cohort II had decreases in measurable disease, although it was not determined whether those decreases were related to fludarabine or to CTL, and 1 patient in Cohort II had 7 months without disease progression. Unlike the patients in Cohort I, fludarabine recipients did not have increases in antidonor CTL responses. Donor cells could not be detected in any of the CTL recipients. CONCLUSIONS Adoptive immunotherapy with allogeneic EBV CTL was safe for patients with recurrent, refractory, EBV-positive HD; and clinical responses may be observed without the establishment of detectable donor lymphoid chimerism. Cancer 2004. © 2004 American Cancer Society. [source] L -Amino acid load to enhance PET differentiation between tumor and inflammation: an in vitro study on 18F-FET uptakeCONTRAST MEDIA & MOLECULAR IMAGING, Issue 5 2006S. Laïque Abstract Labeled amino acids (AA) are tumor tracers for use in nuclear medecine. O -(2-[18F]fluoroethyl)- L -tyrosine (FET) is transported by the L -system, known to function as an exchanger. In vitro utilization of FET, after a preload or prior to an afterload of non radioactive L -amino acids, was evaluated in order to measure the potential effects of AA content on the distinction between tumor and inflammatory lesions. Cellular uptake of FET was studied on rat osteosarcoma cells (ROS 17/2.8) and human leukocytes, initially loaded with nonradioactive L -tyrosine or L -methionine. FET efflux was evaluated from cells loaded with nonradioactive L -phenylalanine after tracer uptake. ROS 17/2.8 showed a higher sensitivity to preload and afterload effects on cellular FET content as compared with the leukocytes. We conclude that preload with L -tyrosine, prior to the administration of FET, may be a potential procedure to improve PET differentiation between tumor and inflammatory lesions. Copyright © 2006 John Wiley & Sons, Ltd. [source] Ligand binding of leukocyte integrin very late antigen-4 involves exposure of sulfhydryl groups and is subject to redox modulationEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 2 2008Si-Yen Liu Abstract Activation of leukocyte integrins is important for selective recruitment of cells from the circulation to tissues. Our previous studies showed that the binding between the integrin very late antigen-4 (VLA-4) and vascular cell adhesion molecule-1 (VCAM-1) is modulated by reactive oxygen species. In this study, we investigated the molecular nature of redox modulation on the activation states of VLA-4 on human leukocytes. We found that ligand binding of VLA-4 induced exposure of sulfhydryl groups on the ,4 peptide. Low concentrations (5,10,µM) of exogenous hydrogen peroxide in the presence or absence of added glutathione enhanced the ligand binding ability of VLA-4 to VCAM-1 and cell rolling on VCAM-1, while higher concentrations (,100,µM) of hydrogen peroxide inhibited the binding. Exogenous hydrogen peroxide and glutathione induced molecular modification of S -glutathionylation on the ,4 peptide. The redox regulation of the VLA-4 binding activity required outside-in signaling and cytoskeleton rearrangement. Our results indicate that ligand binding of VLA-4 involves redox modulations which may play a pivotal role in regulating the activation states of VLA-4 in inflammatory tissues and hence direct leukocyte trafficking. [source] Inhibition of immunosuppressive effects of melanoma-inhibiting activity (MIA) by antisense techniquesINTERNATIONAL JOURNAL OF CANCER, Issue 1 2005Piotr Jachimczak Abstract Melanoma inhibitory activity (MIA) is an 11 kD protein secreted by malignant melanomas. Recent studies revealed an interaction of MIA with epitopes of extracellular matrix proteins including fibronectin. Structural homology of MIA with the binding sites of ,4,1 integrin results in complex interactions of MIA with molecules binding to ,4,1 integrin. As cells of the immune system express ,4,1 integrins (VLA-4), we investigated whether MIA may modulate the function of human leukocytes. Here we describe the effects of MIA on the activation of human PBMCs and auto-/allogeneic lymphokine-activated killer cell (LAK) cytotoxicity in human MIA-negative glioma cell lines and MIA-positive melanoma cell lines in vitro. MIA inhibits PHA- or IL-2-induced human PBMC proliferation in a dose-dependent manner up to 63% (3H-Tdr incorporation) and 59% (cell count), respectively, when added to the cell culture prior to mitogen stimulation. In addition, both autologous (GL and HW) and allogeneic (HTZ-17, HTZ-243 and HTZ-374) antitumor LAK cytotoxicity was reduced by the addition of exogenous rhMIA (500 ng/ml, f.c.). Consequently, endogenous inhibition of MIA expression in human melanoma cells by MIA-specific phosphorothioate antisense oligonucleotides enhanced the autologous LAK-cell activity to the same level as observed in MIA-negative human HMB melanoma cells expressing an MIA-antisense construct. Our results indicate that MIA may contribute to immunosuppression frequently seen in malignant melanomas by inhibiting cellular antitumor immune reactions. Antagonization of MIA activity using antisense techniques may represent a novel therapeutic strategy for treatment of malignant melanomas. [source] Role of topical and nutritional supplement to modify the oxidative stress,INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 6 2002P. Morganti Synopsis Background: Evidence suggests that signs of skin ageing such as wrinkling, ragging and actinic lentigines, may be connected to cumulative oxidative damage incurred throughout our lifetimes. To counteract this oxidative injury, skin is equipped with a network on enzymatic and non-enzymatic antioxidant systems, such as tocopherols, ascorbate polyphenols. All these compounds administered topically by cosmetics or by oral route by diet supplements, have been shown to exert an antioxidant/protective effect in skin or skin cells. Objective: The object of this study was to evaluate both in vitro and in vivo the activity performed by different topical antioxidants and nutritional supplements. Methods: A randomized double-blind placebo-controlled study was carried out for 8 weeks on 30 dry-skinned elderly volunteers, women aged between 48 and 59 years, with moderate xerosis and photoageing. Surface skin lipids, skin hydration and MDA determination were topically detected by 3C System. ROS was evaluated on the blood serum and on IL-3 stimulated human leukocytes by ROS Meter System at 505 nm. All the subjects applied twice a day for 2 months a nanocolloidal gel and/or take a diet supplement by oral route at the quantity of two capsules per day. All the formulations used were antioxidant-enriched (ascorbic acid, tocopherol, alpha-lipoic acid, melatonin, emblica). Results: Oxidative stress and consequently lipids peroxidation decreased from 30 to 40% (P < 0.005) in blood serum of all the subjects treated with antioxidant compounds topically and by oral route. Both free radicals recovered in blood serum and on skin (in vivo) and ROS induced by irradiation of leucocytes with UVB light (in vitro), appear sensibly lower in subjects antioxidant-treated. Conclusions: From the obtained data, it seems possible to conclude that all the compounds used play interesting role as topical and systemic photoprotectants, thanks to their interesting antioxidant property. Moreover, the antioxidant treatment seems to be a promising therapeutic approach also in reducing the oxidative stress of people affected by photoaging. Résumé Les faits semblent montrer que les signes du vieillissement cutané tels que les rides, la perte d'élasticité ou les taches de vieillesse, peuvent être liés aux effets oxydants cumulés subis tout au long de la vie. Pour contrer ces effets oxydants, la peau est équipée d'un réseau de systèmes antioxydants enzymatiques et non enzymatiques tels que les tocophérols, l'ascorbate et les polyphénols. Tous ces composés, administrés par voie topique par des cosmétiques ou par voie orale avec des suppléments alimentaires, se sont révélés exercer un effet antioxydant/protecteur sur la peau ou les cellules de la peau. L'objet de cette étude était d'évaluer aussi bien in-vitro qu'in-vivo l'activité de différents antioxydants topiques et suppléments alimentaires. Une étude randomisée contre placebo en double aveugle a été conduite sur 8 semaines avec 30 volontaires,gés à peau sèche, des femmes de 48 à 59 ans, présentant une xérose et un viellissement modéré. Les lipides à la surface de la peau, l'hydratation de la peau et la MDA ont été suivis de façon topique par le SYSTEM 3 C. Les ROS (Reactive Oxygen Species) ont été déterminés dans le sérum sanguin et sur les leucocytes humains 12-3 stimulés par un SYSTEM ROS-METER à 505 nm. Tous les sujets ont appliqué deux fois par jour pendant deux mois un gel nanocolloïdal et/ou pris des suppléments alimentaires par voie orale à raison de deux gélules par jour. Toutes les formulations utilisées étaient enrichies en antioxydant (acide ascorbique, tocophérol, acide alpha-lipoïque, mélatonine, emblica). Le stress oxydant et par conséquent la péroxydation des lipides diminue de 30 à 40% (p < 0.005) dans le sérum sanguin de tous les sujets traités avec des composés antioxydants par voie topique ou orale. Les radicaux libres retrouvés aussi bien dans le sérum sanguin que dans la peau (in-vivo) et la ROS induite par l'irradiation des leucocytes avec la lumière ultraviolette (in-vitro) apparaissent significativement moins élevés chez les sujets traités aux antioxydants par voie topique ou orale. D'après les données obtenues il semble possible de conclure que tous les composés utilisés jouent un rôle intéressant comme photoprotecteurs topiques et systémiques grâce à leurs intéressantes propriétés antioxydantes. De plus, le traitement antioxydant semble être une approche thérapeutique prometteuse en ce qu'elle réduit aussi le stress oxydant des personnes touchées par le vieillissement. [source] Phosphatidylcholine Reverses Ethanol-Induced Increase in Transepithelial Endotoxin Permeability and Abolishes Transepithelial Leukocyte ActivationALCOHOLISM, Issue 3 2009Katja Mitzscherling Background:, Chronic alcohol abuse increases both intestinal bacterial overgrowth and intestinal permeability to macromolecules. Intestinal permeability of endotoxin, a component of the outer cell membrane of Gram-negative bacteria, plays a crucial role in the development of alcohol-induced liver disease (ALD). As impaired bile flow leads to endotoxemia and the bile component phosphatidylcholine (PC) is therapeutically active in ALD, we tested the hypothesis that conjugated primary bile salts (CPBS) and PC inhibit ethanol-enhanced transepithelial permeability of endotoxin and the subsequent transepithelial activation of human leukocytes. Methods:, For this purpose, we used a model in which intestinal epithelial cells (Caco-2) were basolaterally cocultivated with mononuclear leukocytes. Cells were challenged apically with endotoxin from Escherichia coli K12 and were incubated with or without the addition of CPBS (1.5 mM), PC (0.38 mM), pooled human bile (2%) in combination with ethanol (0 to 66 mM). Results:, Ethanol decreased integrity of intestinal epithelial cell monolayer and enhanced transepithelial permeability of endotoxin. Both the transepithelial permeability of endotoxin and the transepithelial stimulation of leukocytes were nearly completely abolished after the apical supplementation of PC with CPBS, but not by CPBS alone. Ethanol up to 66 mM was not able to reverse this effect. Conclusions:, A considerable part of the therapeutic and preventive effect of PC supplementation in ALD might result from a reduction of ethanol-enhanced permeability of endotoxin through the intestinal barrier. [source] Sensitivity of Actinobacillus actinomycetemcomitans and Capnocytophaga spp. to the bactericidal action of LL-37: a cathelicidin found in human leukocytes and epitheliumMOLECULAR ORAL MICROBIOLOGY, Issue 4 2000D. Tanaka The bactericidal activity of synthetic LL-37, a cathelicidin, was assessed against Actinobacillus actinomycetemcomitans (three strains) and Capnocytophaga spp. (three strains). All strains were sensitive to LL-37, and exhibited 99% effective dose of 7.5-to-11.6 ,g/ml. An amidated form of LL-37, pentamide-37, killed with about the same efficacy as LL-37. Partial inhibition of killing was noted at physiologic concentrations of NaCl, and complete inhibition was observed at 400 mM NaCl. At approximately the 99% effective dose , i.e., 10 ,g/ml , LL-37 also lost activity against A. actinomycetemcomitans in the presence of native or heat-inactivated 10,15% normal human AB serum. Pentamide-37 was less sensitive to serum inhibition than LL-37. In conclusion, certain oral, gram-negative bacteria are sensitive to the bactericidal activity of LL-37 at low concentrations of serum and salt, a condition likely to be found within the membrane-delimited phagolysosome. Modified forms of LL-37, such as pentamide-37, may be more suitable for future therapeutic application in the presence of serum. [source] In vitro immunopotentiating properties and tumour cell toxicity induced by Lophophora williamsii (peyote) cactus methanolic extractPHYTOTHERAPY RESEARCH, Issue 9 2003M. Franco-Molina Abstract Lophophora williamsii, also known as peyote, is found primarily in dry regions from Central Mexico, including the Mexican States of Nayarit, San Luis Potosí, Zacatecas, Nuevo León, Chihuahua, Coahuila and Tamaulipas, to Texas particularly in regions along Rio Grande. Peyote extracts have been associated with stimulating the central nervous system and regulating blood pressure, sleep, hunger and thirst. However, there is no evidence of any effect of peyote on the immune system or against tumour cell growth. The present study was designed to evaluate the in vitro effects of peyote methanolic extracts on some parameters of mouse and human leukocyte immunocompetence and tumour cell growth. Peyote extract (0.18,18 µg/mL) activated nitric oxide production by murine macrophages, and stimulated up to 2.4-fold proliferation of murine thymic lymphocytes. In addition, peyote extract induced up to 1.85-, 2.29- and 1.89-fold increases in mRNA signal of IL-1, IL-6 and IL-8 by human leukocytes. Also examined were the effects of peyote extracts on murine lymphoma L5178Y-R and ,broblastoma L929, and human myeloid U937 and mammary gland MCF7 tumour cell growth using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT). Peyote extracts were toxic for MCF7, L5178Y-R, U937 and L929 (18 mg/mL peyote extract caused 1.3%, 8%, 45% and 60% viability respectively) cell lines. Copyright © 2003 John Wiley & Sons, Ltd. [source] In vitro activity of a cytotoxic factor isolated from human leukocytes,APMIS, Issue 6 2006CARL FREDRIK NAESS-ANDRESEN The aim of the present study was to test the in vitro antimicrobial properties of a cytotoxic factor isolated from human leukocytes and for an effect on DNA synthesis. A microdilution broth method was used to determine MIC values for fungi and bacteria. Flow cytometry was used to examine the effect on DNA synthesis. The MIC values for fungi were in the range 1,128 ,g CF/mL and concentrations 2,4 times the MIC were fungicidal. CF had no effect on bacteria (MIC and MBC values > 1024 ,g CF/mL). Growth experiments performed with increasing concentration of CF showed a dose-dependent effect on growth of the yeasts tested. We confirmed that zinc ions could abrogate the antiproliferative effect of CF. Flow cytometric experiments showed that CF had no effect on the cell cyclus. The present study shows that this endogenous substance isolated from human leukocytes has growth inhibitory properties towards fungi. Because of the origin from human leukocytes, CF may have a role in the non-specific defense against fungal infections. The use of CF may potentially have a role in the treatment of infections caused by fungi. Further investigations to characterize CF chemically and to study the antifungal mechanism are necessary. [source] A novel, rapid, inexpensive, and highly sensitive experiment for demonstration of DNA damage in human leukocytes by single cell gel electrophoresisBIOCHEMISTRY AND MOLECULAR BIOLOGY EDUCATION, Issue 1 2003B. R. Manjunatha Abstract The single cell gel electrophoresis technique (comet assay) has been adopted to demonstrate the DNA damage in human leukocytes of individuals who are habitual smokers. This technique allows the detection of single strand and double strand DNA breaks, which are indicative of the risk of cancer. The method followed is rapid, inexpensive, and a highly sensitive technique for the evaluation of DNA damage and risk assessment in smokers. This experiment should help students understand the effect of cigarette smoking. [source] Evaluation of genotoxic effects in human leukocytes after in vitro exposure to 1950 MHz UMTS radiofrequency fieldBIOELECTROMAGNETICS, Issue 3 2008O. Zeni Abstract In the present study the third generation wireless technology of the Universal Mobile Telecommunication System (UMTS) signal was investigated for the induction of genotoxic effects in human leukocytes. Peripheral blood from six healthy donors was used and, for each donor, intermittent exposures (6 min RF on, 2 h RF off) at the frequency of 1950 MHz were conducted at a specific absorption rate of 2.2 W/kg. The exposures were performed in a transverse electro magnetic (TEM) cell hosted in an incubator under strictly controlled conditions of temperature and dosimetry. Following long duration intermittent RF exposures (from 24 to 68 h) in different stages of the cell cycle, micronucleus formation was evaluated by applying the cytokinesis block micronucleus assay, which also provides information on cell division kinetics. Primary DNA damage (strand breaks/alkali labile sites) was also investigated following 24 h of intermittent RF exposures, by applying the alkaline single cell gel electrophoresis (SCG)/comet assay. Positive controls were included by treating cell cultures with Mitomycin-C and methylmethanesulfonate for micronucleus and comet assays, respectively. The results obtained indicate that intermittent exposures of human lymphocytes in different stages of cell cycle do not induce either an increase in micronucleated cells, or change in cell cycle kinetics; moreover, 24 h intermittent exposures also fail to affect DNA structure of human leukocytes soon after the exposures, likely indicating that repairable DNA damage was not induced. Bioelectromagnetics 29:177,184, 2008. © 2007 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||