Effects of acute and chronic exposure to secobarbital on the activity of hepatic synthesized clotting factors

Male Sprague-Dawley rats were injected with either a single subcutaneous dose of 75 mg of secobarbital, or once daily injections of 20 mg of secobarbital for 7 days. Plasma was collected prior to treatment and 18 hours later (75 mg) or 8 and 15 days later (20 mg). Plasma was analyzed for the platelet count (PLT), prothrombin time (PT), fibrinogen (FIB), and coagulation factor activities for factors II, V, VII, IX, and X. Treatment with a single subcutaneous injection of 75 mg of secobarbital caused statistically significant alterations in every clotting activity measured whereas 7 days of treatment with 20 mg once daily resulted in only 2 clotting factors being abnormal. These two factors returned to pretreatment levels following 7 days of withdrawal of secobarbital. The data indicates that a single larger dose of secobarbital is more influential on hepatic synthesized clotting factor activity than is longer treatment with a lesser dose.     

Adaptation to the UV-induced suppression of phagocytic activity in murine peritoneal macrophages following chronic exposure to solar simulated radiation.

Exposure of certain strains of mice to ultraviolet radiation (UVR) is known to suppress both local and systemic immune responses, including a reduction in the phagocytic activity of peritoneal macrophages. However, in many instances, the immunological effects have been observed following a single or a limited number of doses of UVR from sources containing a higher proportion of UVB than that emitted by the sun. The first aim of the present study was to establish whether a single exposure of C3H/HeN mice to solar simulated radiation (SSR) suppressed the ability of the peritoneal macrophages to phagocytose opsonised sheep red blood cells. The mice were irradiated with SSR from Cleo Natural lamps and a single dose of 31.9 J cm(-2) was found to be the minimal dose for significant suppression of macrophage phagocytic activity. Such a dose did not modulate the surface expression of I-A(k), CD11b, CD86 or FcgammaRII/III (CD32/16) on the macrophages. The second aim was to assess whether repeated SSR exposures with a dose below the minimal immunosuppressive dose affected macrophage activity and, if so, to test for photoadaptation by repeated exposures followed by a single, normally immunosuppressive dose of SSR, and then assaying the macrophage activity. Groups of mice were irradiated on each of 2, 10 and 30 days with 14.9 J cm(-2) SSR, followed in some instances by a single additional exposure of 31.9 J cm(-2) on the same day as the last irradiation. The phagocytic activity of the peritoneal macrophages was tested 24 h later. It was reduced by 32%, 18% and 4% respectively after 2, 10 and 30 repeated exposures to SSR, and by 39%, 21% and 7% respectively after 2, 10 and 30 repeated exposures plus the additional higher dose at the end. Thus, although the macrophage activity was initially suppressed by the SSR, photoadaptation of this immune parameter occurred following repeated exposures.     

Xanthine oxidase activity of thymocytes exposed to x-radiation

Xanthine oxidase activity in thymocytes was studied at different time intervals after X-irradiation with doses of 0.5, 2 and 8 Gy. It was shown that 3 h and later after irradiation, dehydrogenase activity of the enzyme was converted into oxidase one. In the case of arresting the proteolysis by the effect of low doses (up to 0.5 Gy) and at early times the possibility of conversion of the enzyme into the dehydrogenase form was retained. The hyperactivity of the oxidase form of xanthine oxidase was probably a factor of expressing the proteolysis response and cell lysis.     

Effects of acute and repeated exposure to stress on the hypothalamo-pituitary-adrenocortical activity in mice during postnatal development

Hypothalamo-pituitary-adrenocortical (HPA) response to a mild stressful procedure was investigated in mice at Days 8, 10, 12, and 14 of postnatal development. Pups that were removed from the dam and exposed to a novel odor (clean bedding) for 15 min showed higher plasma corticosterone levels than pups whose mother was removed from the cage for 15 min or unhandled pups at all ages, although statistically significant differences were only evident at Days 12 and 14. Lower HPA axis responding in younger mice was not due to immaturity since 8-day-old mice showed a significant and larger increase of plasma corticosterone levels when separated from the mother and isolated from littermates in the absence of bedding. Mice daily exposed to clean bedding (15 min) for the first 13 days of life did not show reduced plasma corticosterone response when reexposed to the stressor at 14 days of age. Conversely, increased plasma corticosterone levels in dams in response to removal of pups was not detectable after repeated exposure to this manipulation (14 days) regardless of the procedure their pups were submitted to, thus ruling out a role of maternal corticosterone passing through the milk on which the pups were fed. These results demonstrate that 15 min exposure to clean bedding is a noninvasive procedure able to elicit HPA axis response in developing mice over a wide age range without producing habituation.     

Effects of chronic exposure to cadmium on prostate lipids and morphology

Cadmium is an environmental toxic metal implicated in human prostate carcinogenesis. The mechanism of its toxicity is not fully understood. Previously, we showed that cadmium exposure induces oxidative stress, especially lipid peroxidation. This study evaluates the effect of chronic exposure to 0.886 mM of cadmium (Cd) per liter in the drinking water on prostate lipid content and metabolism in Wistar rats. We determined the lipid profile and measured the expression of lipogenic enzymes: FAS, GPAT, LPL, DGAT-1, DGAT-2, ACO, CPT-1 and CT, and of certain factors involved in lipid regulation and fatty acid transporters: FAT/CD36, E-FABP, SREBP-2, PPAR-γ and PPAR-α by RT-PCR. Ultrastructure was analyzed by electron microscopy and, as prostate is an androgen controlled gland, AR expression was measured by RT-PCR and Western blot. Cd altered the prostatic lipid profile. Triglycerides (TG) and esterified cholesterol (EC) decreased, free cholesterol (FC) and phospholipids (PL) increased and total cholesterol (TC) did not change. FAS, MDH and IDH activities did not vary but G6PDH decreased significantly in Cd group. Regarding TG synthesis, DGAT-1 decreased while GPAT increased and FAS, LPL and DGAT-2 remained unchanged. Regarding beta oxidation, CPT-1 increased while ACO expression decreased in Cd group. In the PL pathway, CT expression was increased. All these results would justify the decrease of TG in Cd group when compared to control. In the cholesterol metabolic pathway, HMGCoAR and SREBP-2 increased. PPAR-α increased but PPAR-γ did not change. Regarding fatty acid transporters, FAT/CD36 decreased, while E-FABP increased. AR mRNA and protein expression decreased. Ultrastructural analysis showed a decrease in lipid droplets and signs of cellular damage in the Cd group. Cadmium exposure induces important changes in prostatic lipid profile and metabolism, confirmed by the morphology analyses, which also showed signs of cellular damage. These results could be important to further understanding the complex mechanism of cadmium toxicity in prostate and in the development of better treatments for people and animals exposed to the heavy metal. Fellowship from the National Council of Scientific and Technical Investigations (CONICET) – Argentina. Career Scientific Investigator. National Council of Scientific and Technical Investigations (CONICET) – Argentina.     

Effects of weight reduction on neutrophil phagocytic activity and oxidative burst activity in female judoists

This study investigated the effects of short‐term weight reduction on neutrophil functions in female judoists. Sixteen actively competing female judoists were divided into two groups. Eight who required weight reduction were de?ned as the weight reduction group, and the remaining eight were used as the control. Blood samples were taken before, immediately after and 8 days after the match. Phagocytic activity and oxidative burst activity of neutrophils were measured by ?ow cytometry. In the weight reduction group, the phagocytic activity per cell decreased signi?cantly at the end of weight reduction compared with the control group. The rate of neutrophils producing reactive oxygen species and the oxidative burst activity per cell increased signi?cantly at the end of weight reduction in both the control and the weight reduction groups. We concluded that weight reduction, consisting of both intense exercise and energy restriction, might possibly cause both an increase in oxidative burst activity and decrease in neutrophil phagocytic activity in female judoists. However, although exercise increased oxidative burst activity, it did not affect neutrophil phagocytic activity alone. Therefore, to avoid this problem, female judoists are recommended to keep their weight within those limits determined by their class, and which can be reduced by exercise. Copyright © 2003 John Wiley & Sons, Ltd.     

Effects of serum on phagocytic activity and proteomic analysis of tilapia (Oreochromis mossambicus) serum after acute osmotic stress

The objective of the study was to analyze the effect of serum from freshwater (FW) exposed tilapia or from 25 ppt seawater (SW) exposed tilapia on the ability to mediate the phagocytic activity of tilapia phagocytes. To analyze the phagocytic activity, head kidney (HK) and spleen leukocytes were tested in 300 or 500 mOsm medium using three different treatment groups (a) control, (b) addition of 25% serum from freshwater (FW) exposed tilapia, and (c) addition of 25% of serum from 25 ppt seawater (SW) exposed tilapia. HK leukocytes cultured in 300 and 500 mOsm media for 4 h showed an increase of phagocytic ability in the control group as compared to the addition of serum from either FW or SW exposed tilapia. HK leukocytes exposed to 500 mOsm medium showed a higher phagocytic ability than those leukocytes exposed to 300 mOsm medium in each corresponding group. Concurrently, spleen leukocytes in the control group showed a higher phagocytic ability than those leukocytes with the addition of serum from FW or SW exposed tilapia. As compared to spleen leukocytes cultured in 300 mOsm medium, leukocytes cultured in 500 mOsm medium showed an increase of phagocytic ability within their respective group. To further investigate the observed phenomenon, 2D-gel electrophoresis was performed for analyzing the differentially expressed proteins in serum that was thought to influence the phagocytic ability. Up-regulated serum proteins in SW exposed tilapia contained complement C3 protein, NADH dehydrogenase (Ubiquinone) Fe–S protein 3, Mg²⁺-dependent neutral sphingomyelinase, Semaphorins, and Caspase 3. Taken together these results suggest that addition of serum decreased the phagocytic activity in HK and spleen leukocytes in vitro, furthermore, induced proteins semaphorin, complement C3, Mg²⁺-dependent neutral sphingomyelinase, and Caspase 3 are up-regulated in the serum, which might have decreased the phagocytic activity upon exposure to hyperosmotic solutions.     

The phagocytic activity (ingestion and bactericidal activity) of neutrophil leukocytes in chronic myelosis

The paper deals with the results obtained by investigating the function of phagocytes (ingestion and bactericidity) in germs of a stem of staphylococcus aureus 209 and escherichia coli 0-III of mature neutrophilic granulocytes in 30 patients with chronic, not-lymphocytic leukaemia. The ingestion corresponded to the norm. Bactericidity towards the germs of staphylococcus aureus was statistically significant decreased, viz. it was retarded as well as diminished. In certain patients this deviation from the norm found a particularly strong expression, which became evident in clinical appearances. As it was to be expected, no interconnection could be detected between the activity of alkaline granulocytic phosphatase and the function of phagocytosis.     

Effects of acute vs. chronic phorbol ester exposure on transepithelial permeability and epithelial morphology.

In previous experiments we have shown that acute (30 minutes) exposure to phorbol esters or other protein kinase C activators causes increased transepithelial permeability, specifically by the increased paracellular permeability through tight junctions. However, the role of protein kinase C activators in carcinogenesis is predicted upon a chronic exposure of an effective dose at frequent intervals for a prolonged period of time. We therefore sought to determine the effect of chronic phorbol ester exposure on transepithelial permeability by exposing cells of the polar renal epithelial cell line, LLC-PK1, to phorbol esters for time periods as long as 16 weeks. The following changes ensued: (1) after the initial drop in transepithelial resistance due to phorbol ester exposure, i.e., an increase in transepithelial permeability (in the acute phase of exposure), an adaptive response occurs as transepithelial resistances in chronically exposed cultures recover to approximately 50% of control values, (2) the cell sheets in chronically exposed cultures lose their acute responsiveness of transepithelial permeability to phorbol ester exposure, (3) cell sheet architecture changes as cells occasionally multilayer and actual polyp-like cell masses appear at high frequency, and (4) cytosolic protein kinase C activity decreases to 50% of control level with acute exposure and then is further decreased to less than 1% of control level in chronically treated cells; membrane-associated PKC activity is not as sharply decreased. The possible role of transepithelial permeability in carcinogenesis and the value of chronically treated epithelial cell cultures as a model for two-stage carcinogenesis are discussed.     

Effect of ghrelin administration on phagocytic activity in acute cold-restraint stress exposed rats

Ghrelin, an endogenous ligand for growth hormone secretagogue receptor, was identified in the rat stomach. This peptide acts through nitric oxide (NO) by expressing endothelial nitric oxide synthase (eNOS) and down regulating inducible nitric oxide synthase (iNOS) at its gastroproprotective effect against restraint stress induced damage. Recently the ghrelin receptor has also been detected in peripheral systems including immune tissue. We have investigated the possible effect of ghrelin on phagocytic activity of peritoneal macrophages in acute cold-restraint stress (ACRS) exposed rats. The rats were divided into control, stress and ghrelin groups. In ghrelin groups, single dose and three days consecutive dose of ghrelin (20 microg/kg. i.p.) were applied to rats that were exposed to ACRS for 4 h. 1 ml of saline was injected i.p. after ACRS for 3 consecutive days to the rats of the stress groups. Ghrelin administration reduced the increased phagocytic activity induced by ACRS. We conclude that ghrelin exerts an important role at macrophage phagocytic activity in ACRS exposed rats.     

Effects of deoxynivalenol and zearalenone on oxidative stress and blood phagocytic activity in broilers

Effects of dietary contamination with various levels of deoxynivalenol (DON) and zearalenone (ZEA) were investigated on Ross 308 hybrid broilers of both sexes. After hatching, all chickens were fed an identical control diet for two weeks. Then chickens of Group 1 received a diet contaminated with DON and ZEA, both being 3.4 mg · kg^?1, while Group 2 received DON and ZEA at 8.2 and 8.3 mg · kg^?1, respectively. The diet of the control group contained background levels of mycotoxins. Samples of blood and tissues were collected after two weeks. Intake of both contaminated diets resulted in a significantly decreased activity of glutathione peroxidase (GPx) and increased level of malondialdehyde (MDA) in liver tissue, while in kidneys the concentration of MDA was significantly increased only in Group 1. On the other hand, activities of blood GPx and plasma γ-glutamyltransferase (GGT) were elevated in Group 2 only. Activities of thioredoxin reductase in liver and GPx in duodenal mucosa tissues, superoxide dismutase (SOD) in erythrocytes as well as levels of MDA in duodenal mucosa and α-tocopherol in plasma were not affected by dietary mycotoxins. Blood phagocytic activity was significantly depressed in Group 1 and 2. These results demonstrate that diets contaminated with DON and ZEA at medium levels are already able to induce oxidative stress and compromise the blood phagocytic activity in fattening chickens.     

Effects of deoxynivalenol and zearalenone on oxidative stress and blood phagocytic activity in broilers

Effects of dietary contamination with various levels of deoxynivalenol (DON) and zearalenone (ZEA) were investigated on Ross 308 hybrid broilers of both sexes. After hatching, all chickens were fed an identical control diet for two weeks. Then chickens of Group 1 received a diet contaminated with DON and ZEA, both being 3.4 mg kg(-1), while Group 2 received DON and ZEA at 8.2 and 8.3 mg kg(-1), respectively. The diet of the control group contained background levels of mycotoxins. Samples of blood and tissues were collected after two weeks. Intake of both contaminated diets resulted in a significantly decreased activity of glutathione peroxidase (GPx) and increased level of malondialdehyde (MDA) in liver tissue, while in kidneys the concentration of MDA was significantly increased only in Group 1. On the other hand, activities of blood GPx and plasma gamma-glutamyltransferase (GGT) were elevated in Group 2 only. Activities of thioredoxin reductase in liver and GPx in duodenal mucosa tissues, superoxide dismutase (SOD) in erythrocytes as well as levels of MDA in duodenal mucosa and alpha-tocopherol in plasma were not affected by dietary mycotoxins. Blood phagocytic activity was significantly depressed in Group 1 and 2. These results demonstrate that diets contaminated with DON and ZEA at medium levels are already able to induce oxidative stress and compromise the blood phagocytic activity in fattening chickens.     

Effects of selected pharmaceutical products on phagocytic activity in Elliptio complanata mussels

Municipal wastewaters are recognized as a major source of pharmaceutical and personal care products to the aquatic environment, thereby exposing biota to unknown chronic effects. This study sought to examine the immunotoxic effects of pharmaceutical and urban waste products on the freshwater mussel Elliptio complanata. Hemolymph samples were collected and treated in vitro with increasing concentrations of various drugs (bezafibrate, carbamazepine, fluoxetine, gemfibrozil, morphine, naproxen, novobiocin, oxytetracycline, sulfamethazole, sulfapyridine and trimethoprim) and urban waste related chemicals (coprostanol, caffeine, cotinine) for 24 h at 15 degrees C. In a parallel experiment, mussels were caged and placed in two final aeration lagoons for the treatment of domestic wastewaters. At the end of the exposure period, hemolymphs were tested for phagocytic activity, intracellular esterase activity, cell adherence and lipid peroxidation (LPO). The products that most increased phagocytosis were bezafibrate, gemfibrozil and trimethoprim, while novobiocin and morphine reduced its activity. Intracellular esterase activity was reduced most strongly with sulfamethazole, novobiocin, gemfibrozil, bezafibrate and carbamazepine. Cell adherence was decreased by oxytetracycline, novobiocin and naproxen, and increased by gemfibrozil, bezafibrate and sulfapyridine. Exposure to these products also modulated LPO in hemocytes. Coprostanol and naproxen were more potent to reduce LPO while novobiocin and sulfapyridine were the most potent to induce LPO. The potential to induce LPO was positively correlated with the number of functional groups on the molecule (i.e., its nucleophilicity). Mussels exposed to domestic wastewater treatment plant aeration lagoons had decreased intracellular esterase and phagocytic activity as well, suggesting immunosuppression. PPCPs (pharmaceuticals and personal care products) that are recognized to disrupt cytokine signalling network by the nitric oxide pathway and cell permeability were generally the most potent ones. The data suggest that PPCPs have the potential to cause adverse effects on the immune system of bivalves.