RESUMEN
BACKGROUND: Degenerative changes in the temporomandibular joint might be associated with ageing and/or with the loss of occlusal support. OBJECTIVE: The aim of the study was to evaluate whether the inclination of the posterior slope of the articular eminence changes in association with: (i) ageing in patients with maintained occlusal support zones (OSZs); and (ii) the loss of OSZs in elders. METHODS: In this retrospective radiological study, selected orthopantomograms were allocated into the following groups: I-age 18-35, maintained OSZs, II-age 36-60, maintained OSZs, III-age >60, at least one OSZ per side maintained, IV-age >60, loss of all OSZs. The inclination of the articular eminence was measured relative to the Frankfort plane. RESULTS: The mean values of the inclination of the slope of the articular eminence amounted 34.05° ± 5.17°, 36.68° ± 5.65°, 34.86° ± 6.26° and 26.31° ± 5.12° for group I, II, III and IV respectively. There were no significant differences between the groups I to III. Group IV differed significantly from each of the previous groups. CONCLUSIONS: Flattening of the articular eminence is associated with the loss of OSZs rather than ageing.
Asunto(s)
Articulación Temporomandibular , Anciano , Humanos , Radiografía Panorámica , Estudios RetrospectivosRESUMEN
The effect of gamma-irradiation on the physicochemical, organoleptic and microbiological properties of pork was studied, during 43 days of storage at 4±1°C. Irradiation treatments were carried out under air or vacuum packaging on fresh pork loins at a dose of 6 kGy, at two different dose rates: 2 kGy/h and 20 kGy/h. The loins were evaluated for protein sulphydryl content and emulsifying capacity, surface hydrophobicity of proteins and sensorial evaluation. Regardless of the type of packaging and dose rate of irradiation, all irradiated pork samples were effectively prevented from bacterial spoilage for at least 43 days. Meat redness and texture of irradiated loins were relatively well preserved during the storage period, especially when samples were stored under vacuum. Overall, the physicochemical and organoleptic changes in pork loins appeared to be relatively little affected by the 6 kGy dose. No marked changes in emulsifying capacity and protein sulphydryl content of proteins were noted throughout the storage period. However, the hydrophobicity was reduced (P⩽0.05) by the faster dose rate of irradiation and by longer storage.
RESUMEN
Electromagnetic-related alteration of cellular functions is well documented for extremely low-frequency low-energy pulsing electromagnetic fields (ELF-EMF). In this study we examined the in vitro effects of static magnetic fields (SMF) on the cellular immune parameters of the C57BI/6 murine macrophages, spleen lymphocytes, and thymic cells. The cells were exposed in vitro for 24 h at 37 degrees C, 5% CO2, to 250-1500 G SMF. Exposure to the SMF resulted in the decreased phagocytic uptake of fluorescent latex microspheres, which was accompanied by an increased intracellular Ca2+ level in macrophages. Exposure to SMF decreased mitogenic responses in lymphocytes, as determined by incorporation of [3H]thymidine into the cells. This was associated with the increased Ca2+ influx in concanavalin A-stimulated lymphocytes. Furthermore, exposure to SMF produced markedly increased apoptosis of thymic cells, as determined by flow cytometry. Overall, in vitro exposure of immunocompetent cells to 250-1500 G SMF altered several functional parameters of C57BI/6 murine macrophages, thymocytes, and spleen lymphocytes.
Asunto(s)
Apoptosis , Campos Electromagnéticos/efectos adversos , Linfocitos/fisiología , Macrófagos/fisiología , Animales , Calcio/metabolismo , Técnicas In Vitro , Interleucina-2 , Líquido Intracelular , Ratones , Fagocitosis/efectos de los fármacosRESUMEN
Industrial air pollutants from Upper Silesia, Poland, contain over 250 polycyclic and heterocyclic aromatic hydrocarbons and heavy metals, including mutagenic and carcinogenic chemicals that have been shown to form DNA adducts. Over 4 million habitants of Silesia are permanently exposed to the industrial pollution by pulmonary and dermal routes and by contaminated food and water. These chemicals, when examined separately in animals models, were proven immunotoxic. We studied the extrapulmonary immunotoxic potential of a typical mixture of Silesian filter-suspended matter from a selected area, over a specific season and time period. Early changes in the immune system were analyzed in BALB/c mice exposed ip to acute doses of 20-330 mg dust mixture/kg body weight (0.06-1.0 LD50). No major changes were noted for weight and the cellularity of spleen, liver and kidneys. However, dramatic decrease in thymus weight index and thymocyte cell count were noted as early as 24-72 h postexposure, which correlated with almost complete depletion of immature, double-positive CD4+CD8+ thymocytes. Changes in spleen were less profound; however, increased depletion of B cells over T cells was noted at high doses of the suspended matter. Exposure to the airborne dust also decreased cytokine production by spleen cells, such as interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha). Overall, a single exposure to Silesian dust, even at the relatively low 0.06 LD50 dose, affected lymphokine production, suppressed B-cell proliferative response, and depleted thymuses of immature, double-positive CD4+CD8+ cells. A chemical synergism is suspected. To our knowledge, none of the known components of Silesian suspended matter, when examined as a single chemical, was shown to exert such a profound biological effect.
Asunto(s)
Contaminantes Ocupacionales del Aire , Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD8-positivos/efectos de los fármacos , Exposición a Riesgos Ambientales , Timo/efectos de los fármacos , Análisis de Varianza , Animales , Antígenos de Superficie/genética , Linfocitos B/citología , Linfocitos B/efectos de los fármacos , Linfocitos T CD4-Positivos/citología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/citología , Linfocitos T CD8-positivos/inmunología , Células Cultivadas , Aductos de ADN , Sinergismo Farmacológico , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/genética , Compuestos Heterocíclicos/toxicidad , Interferón gamma/metabolismo , Riñón/citología , Riñón/efectos de los fármacos , Dosificación Letal Mediana , Hígado/citología , Hígado/efectos de los fármacos , Recuento de Linfocitos , Metales/toxicidad , Ratones , Ratones Endogámicos BALB C , Polonia , Hidrocarburos Policíclicos Aromáticos/toxicidad , Bazo/citología , Bazo/efectos de los fármacos , Timo/citología , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
The effect of oral indomethacin on the immunosuppressive effect of exercise was examined in exercised untrained female Wistar rats immunized with sheep red blood cell (SRBC) antigens. Intensity of the 1 h exercise was controlled by 0-50 kPa air pressure, generated by a compressor located at the bottom of a water tank, during continuous swimming of the rats, previously immunized with SRBC. After 48-72 h, depending on the ip (intraperitoneal) or iv (intravenous) route of SRBC immunization, the exercise suppressed humoral PFC response and augmented phagocytosis of peritoneum macrophages. These effects occurred only when exercise was performed at 48 h after antigen injection. Animals receiving indomethacin, however, did not show any exercise-related suppression of the PFC response. The data suggest a relationship between exercise-induced immunosuppression and possible increased in vivo prostaglandin synthesis during the intense exercise. Overall, exercise-related suppression of humoral PFC response was dependent on the intensity of the exercise, was time specific, and was reversible by pharmacological blockade of the cyclooxygenase pathway of prostaglandin synthesis.
Asunto(s)
Terapia de Inmunosupresión , Indometacina/farmacología , Condicionamiento Físico Animal , Administración Oral , Animales , Inhibidores de la Ciclooxigenasa/farmacología , Femenino , Técnica de Placa Hemolítica , Inmunoglobulina M/biosíntesis , Inmunoglobulina M/efectos de los fármacos , Indometacina/administración & dosificación , Antagonistas de Prostaglandina/farmacología , Ratas , Ratas Wistar , NataciónRESUMEN
The antiviral drug acyclovir [9-(2-hydroxyethoxymethyl)guanine (ACV)], its 7-isomer (7-ACV) and its two derivatives: N2-acetyl ACV (ac-ACV) and N2,O-diacetyl ACV (diac-ACV) were examined for their potential in vitro lymphotoxicity and in vivo immunotoxicity in mice. In vitro lymphotoxicity of ACV and its acetylated derivatives was low, whereas the 7-ACV isomer enhanced the in vitro cell proliferation in PHA-stimulated cultures. Addition of 2'-deoxyguanosine (dGuo) did not exhibit any inhibitory potential of ACV. However, reduction in the absolute number of CD3+, CD8+, and CD25+ cells, but not Ig+ cells, was noted at high concentrations of ACV and its derivatives, suggesting a selective T cell cytotoxicity. Similarly, the in vivo exposure revealed selective T cell immunotoxicity of ACV and its derivatives since the reduced number of Thy 1.2+ and CD8+ cells was not accompanied with any marked changes in the Ig+ population. The CD4+/CD8+ ratio was affected both in vitro and in vivo by high concentrations of ACV.
Asunto(s)
Aciclovir/toxicidad , Antivirales/toxicidad , Linfocitos B/efectos de los fármacos , Linfocitos T/efectos de los fármacos , Aciclovir/análogos & derivados , Animales , Antígenos de Superficie/análisis , Antígenos de Superficie/biosíntesis , Linfocitos B/inmunología , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Femenino , Ratones , Ratones Endogámicos C57BL , Fitohemaglutininas/farmacología , Bazo/citología , Bazo/efectos de los fármacos , Linfocitos T/inmunologíaRESUMEN
Cell viability and phagocytic activity of coelomocytes from the gastrointestinal tract of Lumbricus terrestris were examined by flow cytometry after in vitro exposure to heavy metals. Control coelomocytes were incubated for 18 h at 15 degrees C, 5% CO2, in Ca(++)-containing LBSS medium with 10(-4)-10(-9) M mercury chloride, methylmercury, cadmium chloride, zinc chloride, lead chloride or lead acetate. Heterogeneity of coelomocyte population was demonstrated by forward scatter (FSC) analysis and cytometric profile showing two different populations of type I/small (60%) and type-II/large (40%) cells. Exposure to either form of Hg, Cd and Zn was relatively highly toxic and affected both cell viability and phagocytosis, whereas Pb was relatively well tolerated by the coelomocytes. A fraction of cells within large coelomocyte population was exceptionally sensitive to the Hg-induced cytotoxicity, which did not affect, however, the relative phagocytic activity of the remaining cells. Overall, at least three different patterns of metal-specific toxicity, affecting both viability and phagocytic functions of earthworm coelomocytes, were confirmed in our in vitro studies. Further characterisation of both the target cells from heterogeneous coelomocyte population and the specific interaction of target cell-xenobiotic can possibly reduce biomonitoring problems in earthworm toxicology and immunotoxicology.
Asunto(s)
Metales/toxicidad , Oligoquetos/efectos de los fármacos , Fagocitosis/efectos de los fármacos , Animales , Tamaño de la Célula , Supervivencia Celular , Células Cultivadas , Monitoreo del Ambiente , Citometría de Flujo , Sistema Inmunológico/citología , Oligoquetos/citología , Oligoquetos/inmunología , Pruebas de ToxicidadRESUMEN
Liposomes act as powerful adjuvants if physically associated with a protein antigen. Their effect on the immune response, however, varies with the nature of this linkage, surface-linked and encapsulated antigens having different properties. Cytometric analysis and cytokine measurements indicate that this difference may be due to the differential activation of T lymphocyte populations. Surface-linked antigen appears to preferentially stimulate CD4+ T cells to proliferate and mature into a typical Th1 phenotype; this is indicated by a positive shift in the CD4+/CD8+ ratio of sensitized splenocytes, a massive production of interferon-gamma, and the absence of interleukin-4 secretion. In contrast, encapsulated antigen, while stimulating spleen cell proliferation, does not significantly affect the CD4+/CD8+ ratio and induces only low levels of interferon-gamma production in the absence of interleukin-4 secretion. These results suggest that CD4+ and CD8+ populations are both expanded in response to encapsulated antigen but that neither typical Th1 nor Th2 phenotypes are induced. High-resolution immunocytochemical investigations show that this differential activation of T cell populations may be related to a different intracellular trafficking of antigens into professional antigen-presenting cells. Whereas surface-linked antigen remains predominantly in endosomal compartments where it may be associated with major histocompatibility (MHC) class II products for presentation to CD4+ T cells, encapsulated antigen escapes into the cytosol, reaching the MHC class I pathway for presentation to CD8+ T cells. The results therefore suggest that both liposomal antigens stimulate cell-mediated immunity albeit differently. This behavioral difference may be of practical importance in the design of adjuvants for the preferential potentiation of specific cytotoxic effector functions.
Asunto(s)
Adyuvantes Inmunológicos/farmacología , Antígenos de Diferenciación de Linfocitos T/farmacología , Liposomas/inmunología , Liposomas/farmacología , Activación de Linfocitos/efectos de los fármacos , Animales , Células Presentadoras de Antígenos/inmunología , Femenino , Inmunidad Celular/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos BALB CRESUMEN
The immune system plays a crucial role in maintaining health; however, accumulating evidence indicates that this system can be the target for immunotoxic effects caused by a variety of chemicals including the environmental pollutants of polychlorinated biphenyls, chlorinated dibenzo-p-dioxins, pesticides, and heavy metals. Adverse chemical-induced immunomodulation, which is studied within the discipline of immunotoxicology, may be expressed either as immunosuppression/immunodepression or immunoenhancement. The former may be manifested either as decreased resistance to opportunistic viral, bacterial, fungal, and other infectious agents or increased susceptibility to cancer. Immunoenhancement on the other hand may either increase the risk of autoimmune reactions or result in allergic reactions. This paper attempts to integrate several aspects of the immune system that are relevant to the assessment of potentially immunotoxic chemicals.
Asunto(s)
Sustancias Peligrosas/toxicidad , Sistema Inmunológico/efectos de los fármacos , Animales , Hipersensibilidad/etiología , Terapia de Inmunosupresión , Ratones , Ratas , Pruebas de ToxicidadRESUMEN
Heavy metals including mercury, lead, and cadmium are present throughout the ecosystem and are detectable in small amounts in the Great Lakes water and fish. The main route of exposure of humans to these metals is via the ingestion of contaminated food, especially fish. Extensive experimental investigations indicated that heavy metals alter a number of parameters of the host's immune system and lead to increased susceptibility to infections, autoimmune diseases, and allergic manifestations. The existing limited epidemiologic data and data derived from in vitro systems in which human peripheral blood leukocytes were used suggested that the human immune system may also be at increased risk following exposure to these metals. The magnitude of the risk that the presence of such metals in the Great Lakes may pose to the human immune system, and consequently to their health, is not known. In this review, the available data with respect to potential adverse effects of heavy metals on the immune system of humans and experimental animals are discussed, and additional data requirements are suggested.
Asunto(s)
Cadmio/toxicidad , Sistema Inmunológico/efectos de los fármacos , Plomo/toxicidad , Mercurio/toxicidad , Contaminantes Químicos del Agua/toxicidad , Adolescente , Adulto , Animales , Canadá , Niño , Femenino , Peces , Contaminación de Alimentos , Great Lakes Region , Humanos , Leucocitos Mononucleares/efectos de los fármacos , Masculino , Ratones , RatasRESUMEN
Induction of contact hypersensitivity (CH) by molybdenum chloride (MoCl5) was determined by auricular lymph node (ALN) test in C57B1/6 mice. The ALN test was further improved by immunophenotyping and cytometric analysis of subset-specific cell in the draining node. Skin sensitization was induced by topical ear exposure to 1.0-50% oxazolone and resulted in a strong dose-related ALN reaction. Analogous exposure to MoCl5 resulted in a weaker but marked dose-related reaction, also manifested as an increase in cell number/ALN. Other differences between the oxazolone-induced strong sensitization and the MoCl5-related ALN reaction were: (1) an increase in the total number of Ig+ cells, which was, however, unchanged in the MoCl5-exposed mice; (2) a significant increase in the total number of large/activated T-cell subsets; and (3) a marked shift in the relative percentage of gated large/activated subsets of ALN cells, which was not observed in the MoCl5-exposed animals. Thus, it appeared that the molybdenum exposure induced a nonspecific increase in the cell number/ALN and was not accompanied by any marked activation of the T-cell subsets. Immunotoxicity of a 14 day subchronic exposure to MoCl5 at 1-100 ppm in food was studied by quantification of splenic humoral IgM response to sheep erythrocytes (SRBC). Plaque-forming cells (PFC) and enzyme-linked immunosorbent assay (ELISA) revealed unchanged humoral exposure in MoCl5-exposed mice. Cytometric assay of fluorescent beads uptake showed unchanged phagocytic activity of peritoneal macrophages from the MoCl5-exposed mice. Immunophenotyping of CD4+, CD8+, Thy 1.2+ and Ig+ cells revealed no effect of MoCl5 exposure on the total count of cell subsets in the ungated populations of spleen, lymph nodes and peripheral blood cells. Molybdenum chloride should thus be considered as a non-immunotoxic and a weak, nonspecific contact irritant.
Asunto(s)
Adyuvantes Inmunológicos/toxicidad , Alérgenos/toxicidad , Dermatitis por Contacto/inmunología , Oído Externo/citología , Ganglios Linfáticos/citología , Molibdeno/toxicidad , Oxazolona/toxicidad , Alérgenos/inmunología , Animales , Formación de Anticuerpos/efectos de los fármacos , Linfocitos B/efectos de los fármacos , Linfocitos B/inmunología , Oído Externo/efectos de los fármacos , Ensayo de Inmunoadsorción Enzimática , Femenino , Ganglios Linfáticos/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Molibdeno/inmunología , Oxazolona/inmunología , Fagocitosis/efectos de los fármacos , Fenotipo , Ovinos/inmunología , Bazo/citología , Bazo/efectos de los fármacos , Bazo/inmunología , Linfocitos T/efectos de los fármacos , Linfocitos T/inmunologíaRESUMEN
Immunoactivating properties of subcutaneously injected small unilamellar vesicles (SUV) and multilamellar liposome vesicles (MLV) were studied in relation to different transition temperatures (Tc) of phospholipids. Liposome-induced proliferative reaction in the popliteal lymph node (PLN) was quantified by subsequent cytometric assay. Early cell activation during the onset of PLN reaction was monitored by immunophenotyping of lymphocyte subsets stained with a panel of monoclonal antibodies (mAbs) and gating the subset-specific large/activated cells. Injection of MLV liposomes containing distearoyl phosphatidylcholine (DSPC) and dipalmityl phosphatidylcholine (DPPC), characterized by relatively high Tc, resulted in a marked PLN reaction, increased numbers of CD4+, CD8+, Ig+ subsets and increased proportions of large/activated EAM+ (CD69+) and CD25+ (IL-2 receptor+) cells. The reaction was dose and time dependent. In contrast, injection of MLV liposomes containing lipids of low Tc, such as egg phosphatidylcholine (egg PC) and dimyristoyl phosphatidylcholine (DMPC), did not show any immunoactivation. In addition, there was a highly reduced immunoactivating potential of small-size SUV liposomes over large-sized MLV of identical phospholipid composition. Generally, both lipid composition and vesicle size appeared to be essential for the immunoactivating potential of liposomes. The data suggest a possible correlation between the Tc of the phospholipid and the immunoactivating potential of the large-sized MLV liposomes.
Asunto(s)
Adyuvantes Inmunológicos/farmacología , Liposomas/química , Liposomas/farmacología , Ganglios Linfáticos/inmunología , Adyuvantes Inmunológicos/química , Animales , Antígenos CD/inmunología , Linfocitos B/inmunología , Relación Dosis-Respuesta Inmunológica , Femenino , Inmunoglobulinas/inmunología , Inmunofenotipificación , Inyecciones Subcutáneas , Liposomas/administración & dosificación , Ganglios Linfáticos/citología , Activación de Linfocitos/efectos de los fármacos , Recuento de Linfocitos , Subgrupos Linfocitarios/inmunología , Ratones , Ratones Endogámicos , Tamaño de los Órganos , Fosfolípidos/química , Fosfolípidos/farmacología , Linfocitos T/inmunologíaRESUMEN
Aminocarb, a phenylsubstituted methylcarbamate pesticide (4-dimethylamino-3-methyl-N-carbamate; matacil), previously suspected of a relatively low immunotoxic potential, was administered by four different exposure routes to C57BL/6 mice. A single sublethal exposure by oral and dermal routes stimulated humoral immune response at a relatively low dose; 1/256 LD50 of aminocarb. Intraperitoneal (i.p.) injection decreased the humoral PFC response, whereas inhalation of aminocarb had no marked effect on peripheral immune status in exposed animals. Thus, i.p. exposure resulted in higher immunotoxicity over oral administration of aminocarb. Similarly, marked route-related exposure differences in immunomodulatory effects of aminocarb were noted for mitogenic stimulation of spleen lymphocytes and mixed lymphocyte response. Other indices, such as delayed type hypersensitivity (DTH) and production of interleukin-2 (IL-2) were unchanged. Interestingly, expression of major histocompatibility complex (MHC) class II by purified, lipopolysaccharide (LPS)-stimulated B cells increased equally after i.p. and oral exposures to aminocarb. Overall, a weak immunosuppressive potential of aminocarb was concluded, which was possibly due to indirect interaction of the pesticide with the immune system. However, aminocarb may represent an autoimmunity-inducing toxic.
Asunto(s)
Carbamatos/administración & dosificación , Carbamatos/toxicidad , Inmunidad/efectos de los fármacos , Insecticidas/administración & dosificación , Insecticidas/toxicidad , Fenilcarbamatos , Administración Cutánea , Administración por Inhalación , Administración Oral , Análisis de Varianza , Animales , Células Productoras de Anticuerpos/efectos de los fármacos , Linfocitos B/inmunología , Femenino , Citometría de Flujo , Hipersensibilidad Tardía , Inyecciones Intraperitoneales , Interleucina-2/análisis , Prueba de Cultivo Mixto de Linfocitos , Ratones , Ratones Endogámicos C57BL , Mitosis/efectos de los fármacosRESUMEN
A popliteal lymph node (PLN) test was further validated for predictive screening of autoimmunity-inducing drugs. Autoimmune-like T-cell activation of streptozotocin (STZ) was compared with the effect of Freund's complete adjuvant (FCA), injected locally into the foot pad of BALB/c mice. Early cell activation in enlarged PLN was monitored by flow cytometry. Injection of both STZ and FCA markedly increased the absolute PLN cell number as well as specific T-helper (CD4+), T-suppressor/cytotoxic (CD8+), and B (Ig+) subsets. However, quantitative analysis of early T-cell activation revealed important differences between STZ-induced PLN reaction and FCA-related lymphoproliferation. At 72 h, the number of cells stained with anti-early activation marker (EAM+; CD69+) increased over 10 times in STZ-enlarged nodes and only 3 times in the FCA-inflamed nodes. Furthermore, different cytometric profiles were noted for STZ-activated and FCA-activated cells stained with anti-interleukin-2 receptor (IL-2R) (CD25+). The data suggest the applicability of early cytometric screening of enlarged PLN for predictive analysis detection of chemicals inducing an autoimmune-like reaction.
Asunto(s)
Adyuvante de Freund/farmacología , Ganglios Linfáticos/efectos de los fármacos , Activación de Linfocitos/efectos de los fármacos , Estreptozocina/farmacología , Linfocitos T/efectos de los fármacos , Animales , Enfermedades Autoinmunes/etiología , Enfermedades Autoinmunes/inmunología , Femenino , Ganglios Linfáticos/inmunología , Ratones , Ratones Endogámicos BALB C , Tamaño de los Órganos/efectos de los fármacos , Fenitoína/farmacología , Procainamida/farmacología , Linfocitos T/inmunologíaRESUMEN
Relationships between in vitro cadmium-related cell cytotoxicity, ultrastructural changes and altered cell cycle were determined at 21-72 h after mitogenic stimulation of C57BL/6 mouse spleen lymphocytes with concanavalin A (Con A). Relatively low doses, 0.6-10 microM cadmium (Cd), added at 4 h after the mitogen activation, induced a significant cell cytotoxicity and reduced the lymphoblastic activity of the cells. Cytometric analysis of the lymphoid cell cycle at 72 h revealed that at concentrations > or = 0.6 microM Cd, the number of cells arrested in G0 + G1 phase increased, whereas the proportions of cells of the S and G2 + M phases were substantially reduced. Staining of cells with fluorescent anti-CD25 monoclonal antibody showed a cadmium-related decreased number and relative mean fluorescence of CD25+ cells, demonstrating a decreased level of interleukin-2 receptor (IL-2R). Furthermore, immunogold ultramicroscopic assay was developed for determination of intracellular interleukin-2 (IL-2) in cadmium-treated lymphocytes. The level of cytoplasmic and nuclear IL-2, localized in situ by colloidal gold ultraimmunocytochemical technique, has been estimated as markedly decreased in cells treated with > or = 1.2 microM Cd, as compared with the untreated controls. Disorganization/fragmentation of mitochondrion cristae and dilatation of cisternae of the Golgi apparatus appeared as the major ultrastructural change in 1.2 microM Cd-treated lymphocytes. Interestingly, addition of cadmium in the incubation medium, up to 4 h after mitogen activation, also interacted with lymphoproliferative mechanisms of cells in G0 + G1, S and G2 + M phase. Overall, multiple ultrastructural changes of Cd-treated lymphoid cells were clearly related with the reduced cell viability and reduced number of activated lymphoblasts.
Asunto(s)
Cadmio/toxicidad , Ciclo Celular/efectos de los fármacos , Cloruros/toxicidad , Linfocitos/efectos de los fármacos , Receptores de Interleucina-2/efectos de los fármacos , Animales , Cloruro de Cadmio , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta Inmunológica , Interleucina-2/antagonistas & inhibidores , Linfocitos/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Receptores de Interleucina-2/antagonistas & inhibidores , Receptores de Interleucina-2/biosíntesis , Bazo/citología , Bazo/efectos de los fármacosRESUMEN
The localization of DNA and RNA adducts was studied at the ultrastructural level using antibodies directed against O6-metG and the protein A-gold technique. Primary rat hepatocyte cultures were exposed for 2-24 h to 5 mM N-nitrosodimethylamine (NDMA) or 0.1 mM N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). In both cases, the O6-metG immunoreactive sites were concentrated in the nucleus and in the rough endoplasmic reticulum (RER) rich cytoplasmic regions. The highest gold labeling density measured was observed at 2 h of NDMA or MNNG treatment. However, after a 24-h exposure, very little labeling was observed in both the nuclear and the cytoplasmic compartments. The rate of disappearance of immunoreactive sites was faster in the cytoplasm than in the nucleus, Untreated control preparations showed no specific immunogold labeling. Furthermore, when cells were exposed first to NDMA and MNNG for a few hours and then to culture medium containing no genotoxin, and subsequently were reexposed to NDMA or MNNG for a few hours, very little labeling of both the nuclear and cytoplasmic compartments was observed. Control preparations without a second genotoxin exposure showed a normal labeling pattern. Control preparations without genotoxin showed no gold labeling. Our results provide evidence for the existence of a cytoplasmic O6-metG repair mechanism that behaves like its nuclear counterpart.
Asunto(s)
Reparación del ADN , Guanina/análogos & derivados , Hígado/metabolismo , Animales , Anticuerpos Antiidiotipos/efectos de los fármacos , Proteínas Bacterianas , Núcleo Celular/efectos de los fármacos , Núcleo Celular/inmunología , Núcleo Celular/metabolismo , Células Cultivadas , Citoplasma , Aductos de ADN , Oro Coloide , Guanina/inmunología , Guanina/metabolismo , Inmunohistoquímica , Hígado/efectos de los fármacos , Hígado/inmunología , Metilnitronitrosoguanidina/toxicidad , N-Metilaspartato/toxicidad , Ratas , Ratas Sprague-DawleyRESUMEN
The lymphoproliferative potential of liposome-trapped streptoztocin (STZ) was compared to the effect of saline-dissolved STZ injected locally into the foot pad of CD-1 mice. Popliteal lymph node (PLN) enlargement and early cell activation of lymphocyte subsets were monitored during the onset of STZ-induced autoimmune-like reaction. Injection of the optimal STZ dose, 0.5 mg/foot pad, markedly increased the absolute PLN cell number as well as specific T-helper (CD4+), T-suppressor/cytotoxic (CD8+), and B-(Ig+) cell subsets stained with fluorescent monoclonal antibodies. Furthermore, there was a marked increase in the number of large/activated CD4+ and CD8+ cells and subsets bearing specific markers of early activation. These included cells stained with fluorescein-conjugated monoclonal antibodies against interleukin-2 receptor (CD25+) and early activation marker (EAM+) (CD69+), and with fluorescein-conjugated peanut agglutinin (PNA+). Surprisingly, the injection of liposome-trapped STZ, at a 1/10 of the optimal dose only, induced a marked PLN enlargement comparable to the effect of optimal STZ dose. The effect of liposome-STZ could be dissociated from the non-drug-containing MLV-related lymphocyte activation. The data suggest several possible advantages from the introduction of chemicals by the liposome route and the subsequent PLN test for chemical-induced autoimmunity. Toxicological advantages could involve better control of chemical exposure, controlled exposure to the water-insoluble substances, drastic reduction of xenobiotic dose, a stronger, clear PLN response and possible elimination or at least restriction of false-negative results, due to the liposome adjuvancity. Overall, application of liposomes as an exposure route potentialized the STZ-induced early lymphocyte activation.
Asunto(s)
Liposomas/administración & dosificación , Activación de Linfocitos/efectos de los fármacos , Estreptozocina/administración & dosificación , Animales , Autoinmunidad , Femenino , Ganglios Linfáticos/efectos de los fármacos , Ganglios Linfáticos/patología , Ratones , Estreptozocina/farmacologíaRESUMEN
The possible interaction between intense exercise, known to suppress the immune response, and nutritive factors, such as polyunsaturated fatty acids (PUFA), was examined in inbred female C57Bl/6 mice. The animals received for 8 wk either a natural ingredient diet or a diet supplemented with 10 g/100 g linseed oil containing over 50% of 18:3 (n-3) alpha-linoleic acid. Other groups received PUFA containing only traces of 18:3 (n-3) fatty acid; beef tallow, containing mostly 18:1 (n-9) saturated fat, safflower oil, an 18:2 (n-6) PUFA, and fish oil, containing longer chain (n-3) PUFA. Each dietary group was divided into two subgroups: sedentary diet controls and exercised animals. Exercise consisted of continuous swimming at high intensity until exhaustion. It was shown in three separate experiments that (1) the primary humoral response to sheep red blood cells, determined by the plaque-forming cell (PFC) assay, was affected by PUFA diet in sedentary animals in the order beef tallow > control diet > safflower oil > fish oil > linseed oil, and (2) the PFC response was suppressed by the exhaustive exercise, as compared to sedentary controls, except for animals fed 18:3 (n-3) linseed oil, where the normal response was noted. Phagocytosis of fluorescent microspheres by peritoneal macrophages, determined by flow cytometry, was significantly lower in exercised animals receiving the linseed oil diet, whereas other diets either increased or did not significantly change the macrophage phagocytic activity, compared to the sedentary diet controls. Spleen lymphocyte subsets were unchanged in exercised animals except for a marked shift from the lymphoid peak toward the erythroid peak. Generally, our data showed a marked immunomodulatory effect of 18-3 (n-3) alpha-linoleic acid on the exhaustive exercise-related immunosuppression, as compared to the effects of other selected PUFA.
Asunto(s)
Grasas de la Dieta/administración & dosificación , Ácidos Grasos Insaturados/administración & dosificación , Tolerancia Inmunológica , Condicionamiento Físico Animal , Animales , Formación de Anticuerpos , Recuento de Células , Femenino , Aceite de Linaza/administración & dosificación , Macrófagos/fisiología , Ratones , Ratones Endogámicos C57BL , Fagocitosis/fisiología , Bazo/citologíaRESUMEN
A non-invasive approach in immunopathological risk assessment was applied for analysis of the in vivo formation of DNA adducts. DNA methylation was studied in peripheral blood lymphocytes (PBLs) collected from Sprague-Dawley rats exposed to a single dose (75 mg/kg b.w.) of N-nitrosodimethylamine (NDMA). Three different techniques were applied for characterization and quantification of DNA adducts: (i) colloidal gold ultraimmunocytochemical localization of O6-methylguanosine (O6-meG)-DNA adducts, using affinity-purified, polyclonal antibody directed against O6-meG, (ii) quantitative assay using enzyme-linked immunosorbent assay (ELISA), amplified by the avidin-biotin (AB) system, and (iii) high-performance liquid chromatography (HPLC). The O6-meG-immunoreactive sites in PBLs seem to be concentrated in the nucleus. However, significant immunolabelling was also noted in the cytoplasm of the in vivo NDMA-exposed PBLs. Control preparations showed no specific gold immunolabelling. The O6-meG-DNA adduct formation in PBLs and hepatocytes, at 2-24 h following the exposure to NDMA, was analogous for both types of cells. The data showed high correlation for the ELISA and HPLC analytical methods. The data suggest an efficient O6-metG-DNA repair mechanism in lymphocytes, possibly analogous to the enzymatic repair of DNA adducts in liver cells.
Asunto(s)
Aductos de ADN/metabolismo , ADN/efectos de los fármacos , Guanina/análogos & derivados , Linfocitos/efectos de los fármacos , Compuestos Nitrosos/toxicidad , Animales , Cromatografía Líquida de Alta Presión , Ensayo de Inmunoadsorción Enzimática , Guanina/metabolismo , Técnicas para Inmunoenzimas , Hígado/metabolismo , Linfocitos/metabolismo , Masculino , Metilación , Ratas , Ratas Sprague-DawleyRESUMEN
The potential immunotoxic effects of mercury chloride on murine bone marrow (bm) cell subpopulations, including analysis of maturation patterns for B-cells, were evaluated by flow cytometric analysis. CD-1 outbred mice were exposed for 28 days to relatively low doses of 25-100 ppm HgCl2 in drinking water and the mercury-related functional cellular changes were validated in a macrophage phagocytosis assay. Lymphocyte subsets from the bone marrow population were stained with PNA lectin and a panel of monoclonal antibodies against cell surface antigens. The incidence of subset-specific staining was also monitored in spleens and thymuses. A dose-effect correlation was noted for the mercury-related activation of macrophage phagocytosis. Subchronic exposure to mercuric chloride resulted in a transient (7-14 day) decrease of the lymphoid/total bm cell ratio and affected the incidence of splenic T-cell subsets, however, without a clear dose-response correlation. The B-cell population in spleen and maturation patterns of B-cells in bm appeared to be unaffected by the mercury exposure. Overall, cytometric analysis of lymphoid cell subsets in murine bone marrow revealed transient and subset-non-specific cell fluctuations after subchronic exposure to inorganic mercury.