Effect of aflatoxin B and rubratoxin B on bacteriophage and rabbit cornea cells

Summary Rabbit cornea cells exhibited a sensitivity to 1 g aflatoxin b₁ and 5 g rubratoxin B per ml of growth medium. No changes were observed in the bacteriophages tested in the presence of 25 g aflatoxin b₁ or 100 g rubratoxin B per ml of medium by the plaque-forming unit method or single-step growth curves.     

The effect of temperature on copper tolerance ofParamecium

Summary The copper tolerance ofParamecium tetraurelia decreases with increased temperatures over the range of 12 C to 34 C. The relationship is linear and the correlation=–0.98. The regression equation has an intercept of 16 M Cu⁺⁺ at 0 C, and tolerance is reduced by 0.33 M for each degree increase in temperature.     

Antiprotozoal activity in citrinin

Summary Citrinin has an inhibitory effect on growth ofT. pyriformis. Citrinin also caused a shift to smaller cell size, particularly at the higher concentrations (25, 50 and 100 g/m1). The mycotoxin exerted only a marginal effect on the respiration of T.pyriformis; but citrinin (25 g/m1) induced an inhibitory effect on DNA, RNA and protein content. The greatest decrease was in RNA, while smaller decreases in protein and DNA were observed. A bioassay employing T.pyriformis was determined; the lower limit of citrinin detection was between 1 and 5 g/m1.     

Immunological changes among workers occupationally exposed to styrene

The functional status of the immune system was investigated in a group of 71 workers exposed to styrene and in 65 control subjects, recruited according to the same selection criteria and comparable as to sex, age, and confounding variables. Air and biological monitoring were used to characterize styrene exposure (median of the main urinary metabolites in the next-morning spot samples: 106 mg/g creatinine). Phenotypic analysis of peripheral blood lymphocytes (PBL) by automated flow cytometry revealed a reduced proportion of T lymphocyte subsets (CD3⁺, CD4⁺ and CD4⁺45⁺), with no changes in CD8⁺, and a higher proportion of B lymphocytes (CD19⁺) among styrene-exposed workers. The exposed workers showed a higher proportion of activation markers, namely DR and interleukin-2 receptors (CD25). Immunoglobulin subclasses were comparable in the two groups. An increased prevalence of abnormally low values was apparent for CD2⁺, CD3⁺, CD4⁺, CD4⁺45⁺ and CD11b subsets among workers exposed to styrene, whereas CD19⁺, DR⁺ and CD25⁺ showed an increased prevalence of abnormally high values. Natural killer-related phenotypes (CD56⁺, CD56+16⁺, and CD56⁺16^–) were more expressed among styrene workers, with average increase of 30%. However, the frequency distribution of the lytic activity of natural killer cells against K-562 target cells was shifted towards lower values in the exposed workers as compared to control subjects. Dose-response relationships between indices of internal dose and prevalence of abnormal values were detectable for T lymphocyte subsets, NK phenotypes, and activation markers. These findings suggest that moderate exposure to styrene is associated with an altered distribution of lymphocyte subsets. The decreased proportion of T lymphocytes, mainly of T helper-inducer cells, could hamper regulatory functions, thus suggesting a negative modulation by styrene exposure. Since a proper balance between immunocycte subsets is important for immunological responses, such changes should be regarded as adverse effects.     

Effects of an omega-3 fatty acid-enriched lipid emulsion on eicosanoid synthesis in acute respiratory distress syndrome (ARDS): A prospective, randomized, double-blind, parallel group study

Background

The use of lipid emulsions has been associated with changes in lung function and gas exchange which may be mediated by biologically active metabolites derived from arachidonic acid. The type and quantity of the lipid emulsions used could modulate this response, which is mediated by the eicosanoids. This study investigates the use of omega-3 fatty acid-enriched lipid emulsions in ARDS patients and their effects on eicosanoid values.

Methods

Prospective, randomized, double-blind, parallel group study carried out at the Intensive Medicine Department of Vall d'Hebron University Hospital (Barcelona-Spain). We studied 16 consecutive patients with ARDS and intolerance to enteral nutrition (14 men; age: 58 ?? 13 years; APACHE II score 17.8 ?? 2.3; Lung Injury Score: 3.1 ?? 0.5; baseline PaO₂/FiO₂ ratio: 149 ?? 40). Patients were randomized into two groups: Group A (n = 8) received the study emulsion Lipoplus^? 20%, B. Braun Medical (50% MCT, 40% LCT, 10% fish oil (FO)); Group B (n = 8) received the control emulsion Intralipid^? Fresenius Kabi (100% LCT). Lipid emulsions were administered for 12 h at a dose of 0.12 g/kg/h. We measured LTB₄, TXB₂, and 6-keto prostaglandin F_1?? values at baseline [immediately before the administration of the lipid emulsions (T-0)], at the end of the administration (T-12) and 24 hours after the beginning of the infusion (T 24) in arterial and mixed venous blood samples.

Results

In group A (FO) LTB₄, TXB₂, 6-keto prostaglandin F_1?? levels fell during omega-3 administration (T12). After discontinuation (T24), levels of inflammatory markers (both systemic and pulmonary) behaved erratically. In group B (LCT) all systemic and pulmonary mediators increased during lipid administration and returned to baseline levels after discontinuation, but the differences did not reach statistical significance. There was a clear interaction between the treatment in group A (fish oil) and changes in LTB₄ over time.

Conclusions

Infusion of lipids enriched with omega-3 fatty acids produces significant short- term changes in eicosanoid values, which may be accompanied by an immunomodulatory effect.

Trial registration

ISRCTN63673813.     

Effect of photocorrosion on cadmium sulfide suspensions applied in animal inhalation studies with CdS particles

Cadmium sulfide aerosol (90 g Cd/m³) was generated from an aqueous suspension for 12 weeks and the ratio of Cd⁺⁺/Cd_total in the suspension and the resulting aerosol was determined. After 4 weeks the concentration of Cd⁺⁺ in the suspension and the aerosol leveled off at 43.5±11.4% and 35.8±6.8%, respectively. Therefore, lung tumors in rats observed after inhalation exposure to such CdS aerosols (Glaser et al. 1990) may have been caused not only by the effect of CdS but also by the influence of inhaled Cd⁺⁺ or CdSO₄. The contribution of CdS particles to the observed lung tumor rate depends on the bioavailability of CdS retained in the lungs. The photochemical decay of CdS in aqueous suspensions only occurred when exposed to light and adjusting the suspension up to pH 3 did not increase the decomposition rate of CdS. Ethanolic suspensions of CdS are much more stable than aqueous ones and experiments with suspensions kept under shield gases showed that the decay of CdS is not dependent on oxygen.     

Heavy Metals (Cr, Zn, Ni, V, Pb, Cd) in Lingonberries (Vaccinium vitis-idaea L.) and Assessment of Human Exposure in Two Industrial Areas in the Kemi-Tornio Region, Northern Finland

The concentration of Cr, Zn, Ni, V, Pb, and Cd were measured in lingonberries (Vaccinium vitis-idaea L.) sampled at 23 sampling sites around a ferrochrome and stainless steel works and opencast chromium mine in the Kemi-Tornio region, Northern Finland. Two different microwave-assisted digestion procedures were used for sample digestion, i.e., a mixture of HNO₃ + H₂O₂ and a mixture of HNO₃ + H₂O₂ + HCl + HF + H₃BO₃. According to the results, the digestion procedure with the mixture of HNO₃ + H₂O₂ underestimated especially the Cr concentrations in plant material. The maximum concentrations of Cr (1.3 mg kg^–1, wet weight), Ni (358 g kg^–1; ww), V (36 g kg^–1; ww), and Cd (2.4 g kg^–1; ww) in the immediate vicinity of the point sources were 33, 6, 4, and 8 times higher than the background levels, respectively. The dietary intakes of Cd and Pb were assessed and compared to the health criteria recommendations set by the joint Food and Agriculture Organization and World Health Organization Expert Committee on Food Additives (JECFA). The results showed that, depending on the consumption of lingonberries, human exposure based on the mean concentrations for Pb and Cd varied between 0.04% and 0.07% for Pb and between 0.04% and 0.09% for Cd compared to the tolerable total quantities of 25 g kg^–1 for Pb and 7 g kg^–1 for Cd per body weight per week set by JECFA.     

Effects of Pb and Ni stress on oxidative stress parameters in three moss species

Antioxidative responses of the mosses Hypnum plumaeforme, Thuidium cymbifolium, and Brachythecium piligerum to short-term Pb and Ni stress were investigated. Both Pb and Ni treatment increased the formation of reactive oxygen species and lipid peroxidation, decreased superoxide dismutase (SOD), and catalase (CAT) activities in H. plumaeforme and T. cymbifolium. However, SOD activity in B. piligerum was increased under 10 mM Pb stress and Ni increased CAT activity in B. piligerum under 1 mM Ni stress. Peroxidase (POX) activity in the three mosses was increased by Pb and Ni exposure, indicating that POX plays an important role in preventing heavy metal-induced oxidative stress. The accumulation of O₂⁻ and H₂O₂ in mosses is related to the decline in SOD and CAT activities. B. piligerum is the most sensitive and T. cymbifolium is the most tolerant species to Pb and Ni stress among the three bryophytes.     

Mitochondrial bioenergetics as affected by cationic detergents

This paper examines the accumulation and toxicity mechanism of a cationic detergent, cetyltrimethylammonium (bromide) (CTAB), in energized rat liver mitochondria. The results suggest that: (1) the CTAB ion is accumulated in the mitochondrial matrix by a membrane potential-driven uptake mechanism; (2) accumulation may lead to a toxic effect, since it gives rise to collapse of the mitochondrial membrane potential () which is correlated with ATP synthesis and which regulates Ca⁺⁺ uptake; (3) collapse of may be due to enhanced permeability of the mitochondrial membrane to the ions (detergent effect); and (4) collapse and Ca⁺⁺ and K⁺ release were also observed in another cationic detergent, NTAB, but not in the presence of anionic detergents.     

Restoration of immunoregulation in splenic lymphocyte populations of mice fed reduced dietary protein

Moderate, acute reduction of dietary protein in young mice often leads to increases in humoral immune responses. To test the hypothesis that reduction of dietary protein affects T lymphocyte regulation of the humoral immune response, in vitro humoral immune responses to sheep erythrocytes (SRBC) and bromelain-treated mouse erythrocytes (BrMRBC), were examined in BDF₁ and BALB/c mice fed diets low in protein (4% or 6% casein) compared with well-fed (20% casein) controls. In addition, the immunoregulatory splenic T lymphocyte subset profile was evaluated in mice fed the 4% and 20% casein diets. Groups of female BDF1 and BALB/c mice 5 weeks of age were fed one of the three diets for 5 weeks. Mice fed the 4% casein diet exhibited less body weight and splenic lymphocyte number than mice from the other two dietary groups. BDF₁ but not BALB/c mice fed the 4% casein diet exhibited significantly increased in vitro and in vivo immune responses to optimal or high doses of SRBC. On the other hand, both BDF₁ and BALB/c mice fed the 4% casein diet exhibited a significantly higher immune response to BrMRBC. The increased response of 4% casein-fed BDF₁ mice was related to an inability to generate adequate specific immunoregulatory T cells involved in suppressing the response. Co-culturing with Lyt1⁺ or Lyt2⁺ T cells from well-fed mice regulated downwardly the enhanced autoimmune, anti-BrMRBC response of mice fed the 4% casein diet. Decreased suppressor T lymphocyte activity in BDF₁ mice, but not BALB/c mice fed the 4% casein diet was confirmed by the significant depression of the Lyt2⁺ suppressor T cell number in the spleen evaluated by direct immunofluorescence using monoclonal antibodies which identify T lymphocyte subsets. These results indicate that moderate, acute reduction of dietary protein in young mice affects the regulatory functions of T cells but not the differentiation of B cells to antibody-forming plasma cells. This effect seems to be dependent upon the strain of mouse used.     

Toxicity of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin in larval and adult forms ofRana catesbeiana

Summary Varying doses of TCDD ranging from 25 to 1000 g/kg were administered to the larval and adult forms of the American bullfrog,Rana catesbeiana. Doses of TCDD as high as 1 mg/kg failed to have any significant effect upon survival or completion of metamorphosis in tadpole and doses of up to 500 g/kg had no effect on survival of adult frogs. Histopathological examination of various tissues from the metamorphosed tadpoles and adult frogs failed to show any abnormalities.This work was supported by USPHS Grant ES00267. The Training support of ES 07028 is also gratefully acknowledged.     

Effects on ionic composition of blood and tissues ofAnodonta grandis grandis (Bivalvia) of an addition of aluminum and acid to a lake

To test the hypothesis that summer low pH, episodic events cause stress and mortality in aquatic organisms including mussels, alum (aluminum sulfate) was added near the point of inflow to Lake 114 in the Experimental Lakes Area, northwestern Ontario from 3 to 5 July 1984. Lake 114 was at pH 5.9 before the alum addition. The alum produced measured extremes of pH 4.5 and [Al] of 2,237 g/L near the point of addition. This study examined the effects of the alum addition on ionic concentrations of blood and tissue (gills, adductor muscle, foot and visceral mass) of the floater mussel,Anodonta grandis grandis. Mussels were collected from a second lake, 377, and introduced into Lake 114 at five locations five days before the alum addition. In response to transfer from the oligotrophic, unmanipulated Lake 377 to acidified Lake 114 (pH 5.9), blood of mussels showed a marked elevation of [Ca⁺⁺], decline in [Mg⁺⁺] and a temporary increase in [Cl^–] but no change in [Na⁺], [K⁺] or [SO₄ ⁼]. During the alum addition, in mussels near the point source of the alum addition, blood [Na⁺] and [Cl^–] declined and [Ca⁺⁺] became still more elevated. Mussels suffered no mortality associated with the alum addition and almost no mortality during 26 days in Lake 114. Gill increased in [Al], [Ca], [Mn], declined in [Na] and showed no change in [Cd] in mussels near the alum addition. Visceral mass and adductor muscle also had lower [Na] in mussels near the point of alum addition. We attribute the increase in blood [Ca⁺⁺] to the dissolution of the Ca stores in the shell and/or mantle of mussels. This would provide protection to the mussels during short-term declines in pH such as spring or summer episodic events. Never-theless, chronic exposure to small decreases in pH by mussels, already near the limits for obtaining sufficient Ca⁺⁺, might be intolerable. It follows that acidification to the pH of 5.9 of soft water lakes containing mussels would be expected to lead to the loss of A.g. grandis from these waters.     

Uptake of36Cl-toxaphene in the cockroach,Leucophaea maderae (Fabr.)

Summary Toxaphene was only slightly toxic toL. maderae. The ED-50 at 120 h was 299.5 g/g. Uptake of a sublethal dose of³⁶Cl-toxaphene was examined in several tissues. At most time intervals between 2–96 h, greater concentrations were found in VNC than haemolymph, fat body, or alimentary canal. At 120 h, tissues of symptomatic insects possessed significantly greater amounts of radiolabeled material than asymptomatic, except for fat body where no difference was noted.     

SPF32629A and SPF32629B: enantioselective synthesis, determination of absolute configuration, cytotoxicity and antibacterial evaluation

We report herein an efficient enantioselective synthesis of SPF32629A and SPF32629B through one-pot enantioselective reduction and protecting-group-free regioselective O-acylation strategy. The absolute configuration of the enantiomerically pure isomers was established by Mosher ester analysis. The inhibitory potencies of the synthesized compounds were assayed in vitro against a panel of microorganisms and against A549 human lung adenocarcinoma cell line. Compounds 2, 11 and 12 displayed moderate to potent antibacterial activity against all the tested strains and compounds 7, 8, 2, 11 and 12 exhibited significant cytotoxicity in a dose-dependent manner with an IC₅₀ values ranging from 2.92 to 4.14 μg/ml and 8-11 μM.     

Aspergillus flavus and aflatoxins B1, B2, and M1 in corn associated with equine death

Corn from an Arkansas farm, where three horses died and others became sick, was investigated for causative principles. Necropsy of the three horses revealed what appeared to be severe hepatic necrosis. Histopathological examination indicated a pattern of hepatic lesions that was suggestive of aflatoxin contamination of the feed. Mycological examination of the corn by dilution plating revealed 95% of the colonies asAspergillus flavus. Chemical analysis of the corn for mycotoxins was positive for aflatoxin B₁, B₂, and M₁ at concentrations of 114, 10, and 6 g/Kg, respectively. Cyclopiazonic acid, sterigmatocystin, and theFusarium toxins, vomitoxin (deoxynivalenol), T-2 toxin, and diacetoxyscirpenol, were not detected. The presence of aflatoxin metabolites in the moldy corn and the presence of appropriate lesions were compatible with the diagnosis, equine aflatoxicosis.     

Anin vitro model for the binding of polybrominated biphenyls in environmentally contaminated blood

Spiking blood with¹⁴C-labeled 2,2, 4,4,5,5-hexabromobiphenyl (¹⁴C-HxBB) or a mixture of 2,2,4,5,5-pentabromobiphenyl, 2,2,4,5,6-pentabromobiphenyl and¹⁴C-HxBB has been found, in comparative measurements, to be a representative model of polybrominated biphenyl (PBB) contaminated blood from Michigan residents. Blood components were obtained by Ficoll-Hypaque techniques, apolipoprotein B and A fractions by immunoprecipitation with specific antisera; congeners were quantified by negative chemical ionization mass spectrometry or scintillation counting. The distribution of PBB among plasma, erythrocytes, mononucleocytes and polymorphonucleocytes was 89:9:1:1. In serum, 20% of the PBB was not bound to protein. The remaining 80% was bound to apolipoproteins B and A in a 41 ratio, which is close to the ratio (by weight) of the lipid content of these apolipoproteins. No preferential absorption of PBB congeners occurred in the examined blood compartments.on leave from Department of Chemistry, University of Queensland, Brisbane, 4067, Australia     

Effect of the insecticide Zectran (Mexacarbate) on several algae

Summary Field samples of freshwater algae were examined to determine the effect of the insecticide Zectran on photosynthesis rate. Concentrations of Zectran between 10 and 10³ parts per billion (ppb) affected neither O₂ production nor NaH¹⁴CO₃ uptake in any of the seven genera tested. However, Zectran at a concentration of 10⁴ ppb after 1 hour effected a reduction in photosynthesis ofChroococcus,Oedogonium and in a mixed sample composed ofZygnema,Mougeotia andSpirogyra. Mougeotia,Spirogyra andSchizogonium were not affected by exposure to 10⁴ ppb Zectran after 1 hour, but O₂ production was significantly reduced after 24 hours of exposure to this same concentration.This work was supported by an Environmental Protection Agency grant -68-01-2672.     

Air,hand wipe,and surface wipe sampling for Bisphenol A (BPA) among workers in industries that manufacture and use BPA in the United States

For decades, bisphenol A (BPA) has been used in making polycarbonate, epoxy, and phenolic resins and certain investment casting waxes, yet published exposure data are lacking for U.S. manufacturing workers.

In 2013–2014, BPA air and hand exposures were quantified for 78 workers at six U.S. companies making BPA or BPA-based products. Exposure measures included an inhalable-fraction personal air sample on each of two consecutive work days (n = 146), pre- and end-shift hand wipe samples on the second day (n = 74 each), and surface wipe samples (n = 88). Potential determinants of BPA air and end-shift hand exposures (after natural log transformation) were assessed in univariate and multiple regression mixed models.

The geometric mean (GM) BPA air concentration was 4.0 µg/m³ (maximum 920 µg/m³). The end-shift GM BPA hand level (26 µg/sample) was 10-times higher than the pre-shift level (2.6 µg/sample). BPA air and hand exposures differed significantly by industry and job. BPA air concentrations and end-shift hand levels were highest in the BPA-filled wax manufacturing/reclaim industry (GM_Air = 48 µg/m³, GM_Hand-End = 130 µg/sample) and in the job of working with molten BPA-filled wax (GM_Air = 43 µg/m³, GM_Hand-End = 180 µg/sample), and lowest in the phenolic resins industry (GM_Air = 0.85 µg/m³, GM_Hand-End = 0.43 µg/sample) and in the job of flaking phenolic resins (GM_AIR = 0.62 µg/m³, GM_Hand-End = 0.38 µg/sample). Determinants of increased BPA air concentration were industry, handling BPA containers, spilling BPA, and spending ≥50% of the shift in production areas; increasing age was associated with lower air concentrations. BPA hand exposure determinants were influenced by high values for two workers; for all other workers, tasks involving contact with BPA-containing materials and spending ≥50% of the shift in production areas were associated with increased BPA hand levels. Surface wipe BPA levels were significantly lower in eating/office areas (GM = 9.3 µg/100 cm²) than in production areas (GM = 140 µg/100 cm²).

In conclusion, worker BPA exposure was associated with tasks and conditions affecting both inhalation and dermal exposure. The potential for BPA-related health effects among these workers is unknown.     

Changes in the relationship between marriage and preterm birth, 1989-2006

ObjectiveMaternal marriage has historically been protective against preterm birth (PTB); however, social norms and behaviors surrounding marriage have changed over time in the United States. We analyzed secular trends in the relationship between marriage and PTB.MethodsWe collected data about all births in Michigan between 1989 and 2006 to assess (1) the relationship between marital status and PTB and moderately PTB risk by year, and (2) the relationship between married and unmarried status and PTB and moderately PTB by year relative to similar marital status in 1989.ResultsAmong nearly 2.4 million births between 1989 and 2006, PTB risk among married mothers increased while risk among unmarried mothers decreased. In adjusted models, married status became less protective against PTB relative to unmarried status over time by year, and was associated with higher risk of PTB over time. Moderately PTB risk increased among both married and unmarried groups, but more so among married mothers.ConclusionOur findings suggest that marriage is becoming less protective against PTB over time. The influence of social factors on risk for adverse birth outcomes is likely dynamic, suggesting that ongoing revisions to our understanding are in order.Defined by the World Health Organization as birth before 37 completed weeks of gestation, preterm birth (PTB) is a major contributor to perinatal and neonatal mortality, serious neonatal morbidity, and moderate to severe childhood disability.¹ In wealthy countries such as the United States, 6%–10% of all births are preterm, and deaths to preterm infants comprise more than two-thirds of all neonatal deaths.²Married status has long been associated with a lower risk of PTB,^1,3,4 as well as other adverse perinatal outcomes including low birthweight,^3,5,6 small-for-gestational-age infants,^3,5,7,8 and fetal and neonatal mortality.⁹ Several factors may explain the relationship between marital status and risk for adverse birth outcomes, including differences between married and unmarried mothers in financial security,^10–12 health-care access,^4,13 social support, and mental health.^14–18The presumed health-promoting effect of marriage has led to its promotion as a positive social construct that may improve the health of populations.^19–22 However, in the past two decades, the role of marriage has changed in North America. Bumpass and Cherlin independently contended that marriage has undergone a “decline in significance” and a deinstitutionalization as a result of a deterioration of the marital norms that shape partners’ social behaviors and a trend toward individuation, personal choice, and self-development.^23,24 It is plausible, therefore, that as norms governing partners’ marital behaviors have deteriorated over time, mechanisms mediating the relationship between marriage and PTB risk may have weakened, thereby altering the relationship between marital status and the risk of PTB. For example, as partners involved in marital relationships become more independent and self-oriented, and therefore invest fewer of their resources (e.g., money, time, and attention) in one another, it follows that the financial and social support afforded married mothers via their marriages may diminish, with plausible downstream effects on maternal mental health and access to health-care services.In addition, the increasing incidence of PTB in wealthy countries in the past two decades has been shown to be partially attributable to the increasing rate of obstetric interventions,²⁵ such as cesarean section and induced labor.²⁶ Compared with unmarried mothers, married mothers have been shown to have more ready access to health services.^4,13 It is possible that a higher rate of later-term obstetric interventions among married vs. unmarried mothers could change the relationship between marital status and PTB over time by increasing the incidence of obstetrically induced PTB among married vs. unmarried mothers.We hypothesized that the apparent protective effect of marriage on risk of PTB has decreased with time as a result of the aforementioned mechanisms. We analyzed secular trends in PTB, very PTB, and moderately PTB risk among married and unmarried mothers over time using data from one U.S. state between 1989 and 2006.