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E Casillas

Publications and source records attributed to E Casillas.

16 recordsLinked to original sources
PubMed2003

Assessment of seasonal variability of cytochemical responses to contaminant exposure in the blue mussel Mytilus edulis (complex).

A selected suite of cytochemical parameters in Mytilus edulis are altered in response to field and laboratory exposure to chemical contaminants. These biomarkers include lysosomal stability, nicotinamide adenine dinucleotide phosphate (NADPH)-ferrihemoprotein reductase activity, liposfuscin deposition, and accumulation of lysosomal and cytoplasmic unsaturated neutral lipid. Normal variations in physiological processes (influenced by exogenous seasonal changes in temperature, salinity, food availability, etc.) may alter the sensitivity of these biomarkers to contaminant exposure. To address this issue, M. edulis (complex) were sampled monthly from a reference nonurban site (Coupeville, Penn Cove) and a polluted urban site (Seacrest, Elliott Bay) in Puget Sound, WA, for a period of 15 months. Physiological measurements including total length, total weight, somatic and mantle weights (an indication of gonadal development and reproductive status), condition index, and the presence or absence of hemic neoplasia (HN, or leukemia) were recorded. Significant differences in lysosomal stability, lysosomal and cytoplasmic unsaturated neutral lipids, lipofuscin deposition, and NADPH-ferrihemoprotein reductase activity in cells of the digestive gland or digestive tubules were generally found in mussels taken throughout the year from Seacrest compared to mussels sampled from Coupeville, consistent with exposure to chemical contaminants. No seasonally influenced suppression of the entire suite of parameters as measures of contaminant exposure was evident. Therefore these biomarkers can be used to evaluate contaminant exposure in mussels throughout the entire year.

Adaptation, Physiological↗
PubMed1999

Environmental contaminants and the prevalence of hemic neoplasia (leukemia) in the common mussel (Mytilus edulis complex) from Puget Sound, Washington, U.S.A.

The relationship between hemic neoplasia, a blood cell disorder in bivalve molluscs, and chemical contaminants was evaluated in the common mussel (Mytilus edulis complex). Hemic neoplasia (HN) is endemic to mussel populations in Puget Sound. The prevalence of hemic neoplasia ranged from 0 to 30% in mussels from nine sites in Puget Sound, Washington. Organic chemical contamination in sediment from these sites range from 0.1 to 64.0 ppm of polycyclic aromatic hydrocarbons (PAHs) and 0.07 to 0.50 ppm chlorinated hydrocarbons. No relationship between the body burden of environmental contaminants and the prevalence of HN in mussels was identified. To evaluate the short-term ability of chemical contaminants to induce HN in mussels, mussels, from a site where mussels were previously determined to be HN free, were fed microencapsulated PAHs (composed of a mixture of phenanthrene, flouranthene, and benzo[a]pyrene) or PCBs (Aroclor 1254) and the prevalence of HN was assessed after 30 days of exposure. Although an apparent increase in HN prevalence (20 to 30%) was observed in all treatments groups except the untreated controls, no significant difference in the prevalence of HN was observed between the control group of mussels fed corn oil (vehicle) and mussels fed either PAHs or PCBs in corn oil. A long-term (180-day) exposure study was conducted to evaluate the influence of PAHs or PCBs in modulating the prevalence of HN in a mussel population already exhibiting a moderate HN prevalence. Mussels, from a site where mussels were previously determined to exhibit a background prevalence of HN, fed microencapsulated PAHs, PCBs, and corn oil (vehicle) over a long time period (180 days), revealed an apparent increased prevalence of HN (30 to 40%) above the low levels (20%) initially present. However, no significant difference in the prevalence of HN was observed between the control group of mussels fed corn oil (vehicle) and mussels fed either PAHs or PCBs in corn oil. Although chemical contaminants have been proposed as a modulating factor in the development and promotion of HN in bivalve molluscs from environmentally stressed and degraded habitats, we find no evidence that chemical contaminants induce or promote the development of HN in the mussel M. edulis complex.

Animals↗
PubMed1997

Comparative bioaccumulation of chlorinated hydrocarbons from sediment by two infaunal invertebrates.

Bioaccumulation of chlorinated hydrocarbons (CHs) from field-contaminated sediments by two infaunal invertebrates, Rhepoxynius abronius (a non-deposit feeding amphipod) and Armandia brevis (a nonselective, deposit-feeding polychaete), was examined and species responses were compared. Sediments were selected over a large geographical area of the Hudson-Raritan estuary to assess the potential for bioaccumulation from a typical urban estuary. Unlike polycyclic aromatic hydrocarbons (PAHs) from these sediments, concentrations of CHs in interstitial water (IW) indicated that partition coefficients (Koc) were generally as expected, especially when based on predicted, nonsorbed, interstitial water CH concentrations (IWfree). Correlations between amphipod and polychaete tissue residues revealed that these species were responding similarly to a gradient of CH concentrations in sediment. While tissue residues and BAFloc (lipid/organic carbon normalized bioaccumulation factor) values for the trichlorobiphenyls were similar for both species, accumulation in the polychaete was three to 10 times higher for the more hydrophobic PCBs, which was attributed to differences in the route of exposure. A negative correlation between the bioaccumulation factor (BAF) and total organic carbon (TOC) was found for both species, which was expected according to equilibrium partitioning theory. Because it was assumed that the amphipod was not feeding in these tests and the polychaete was ingesting sediment, comparison of their tissue residues and bioaccumulation factors was useful for highlighting the importance of sediment ingestion, especially for short-term, nonequilibrium exposures. These results may also help elucidate the limitations associated with assessing bioaccumulation and the resultant toxic response in standard 10-day toxicity tests with similar invertebrates.

Animals↗
PubMed1994

Suppression of B-cell mediated immunity in juvenile chinook salmon (Oncorhynchus tshawytscha) after exposure to either a polycyclic aromatic hydrocarbon or to polychlorinated biphenyls.

Juvenile chinook salmon (Oncorhynchus tshawytscha) were injected intraperitoneally with either the polycyclic aromatic hydrocarbon, 7,12-dimethylbenz[a]anthracene (DMBA)1 or with the commercial polychlorinated biphenyl (PCB) mixture, Aroclor 1254, to assess effects on the B-cell mediated immune response. B-cell mediated immunity was assessed by examination of the primary and secondary plaque-forming cell (PFC) responses of anterior kidney and splenic leukocytes to a T-independent antigen, TNP-keyhole limpet hemocyanin (TNP-KLH). Salmon exposed to DMBA at dosages of 20% or 1% of the 96 hr LD50 (12.7 mg and 0.6 mg/kg of salmon, respectively) or to PCBs at a dosage of 20% of the 96 hr LD50 (54.0 mg/kg of salmon) exhibited a suppressed PFC response. The secondary PFC response of anterior kidney and splenic leukocytes to both antigens and the primary splenic PFC response to TNP-LPS were suppressed in salmon exposed to either DMBA or PCBs. However, only the primary PFC response of anterior kidney leukocytes to TNP-LPS was suppressed in salmon exposed to PCBs and no suppression of this response was observed in salmon exposed to DMBA. Neither anterior kidney or splenic leukocytes from salmon exposed to DMBA or PCBs showed an altered primary PFC response to the T-dependent antigen, TNP-KLH. These results suggest that B-cell mediated immunity in salmon is suppressed by known mammalian immunosuppressants and that suppression of the PFC response observed previously in salmon from an urban estuary may be due to contaminant exposure.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1989

Effect of bromobenzene and O-bromophenol on kidney and liver of English sole (Parophrys vetulus).

1. English sole (Parophrys vetulus) were injected intraperitoneally with a single dose of 9.8 mmol bromobenzene/kg of fish or 1.9 mmol O-bromophenol/kg of fish, both known renal toxicants in mammals. 2. Kidney, liver, gill spleen, intestines, heart and blood samples were subsequently obtained up to 48 hr post-injection for determination of microscopic lesions, concentrations of selected tissue antioxidants (glutathione and ascorbic acid), and selected serum parameters. 3. Bromobenzene and O-bromophenol were both found to be hepatotoxic in English sole, as indicated by the presence of hepatocellular coagulation necrosis and fatty change in the liver, altered glutathione and ascorbic acid levels in liver tissue, elevated serum aspartate aminotransferase and alkaline phosphatase activity and increased serum glucose and triglyceride levels. 4. No evidence of nephrotoxicity was found in English sole exposed to either toxicant. 5. It is concluded that bromobenzene and O-bromophenol cannot be used as model nephrotoxicants but can be used as hepatotoxicants in English sole.

Alkaline Phosphatase↗
PubMed1987

Comparison of transketolase activity and thiamin pyrophosphate levels in erythrocytes and liver of rainbow trout (Salmo gairdneri) as indicators of thiamin status.

Yearling rainbow trout (Salmo gairdneri) were fed a purified diet with and without thiamin supplementation for 30 wk, at which time overt signs of thiamin deficiency appeared in the deficient group. Overt signs of thiamin deficiency were anorexia, darkening and ataxia. Death rapidly followed the development of overt thiamin deficiency. Transketolase activity and thiamin pyrophosphate levels were measured monthly in erythrocyte and liver samples. Significant differences in erythrocyte transketolase activity between fish fed the thiamin-deficient and control diets were measured after 24 wk of feeding. No significant difference in liver transketolase activity was found between trout fed diets with or without thiamin supplementation. Thiamin pyrophosphate levels were significantly lower in erythrocytes and liver of fish fed the thiamin-deficient diet after 16 wk of feeding. Thiamin pyrophosphate levels in erythrocytes and liver were found to be a more sensitive indicator of thiamin status of rainbow trout than erythrocyte or liver transketolase activity.

Animals↗
PubMed1987

Magnesium, calcium and PTH relationships in dialysis patients after magnesium repletion.

Sixteen end-stage renal disease patients who received hemodialysis for 2.9 years with no magnesium in the dialysate were evaluated for serum calcium, magnesium and parathyroid hormone (PTH) status. Eleven of these patients became hypomagnesemic with subnormal total and ultrafiltrable serum Mg concentrations (low-Mg group). The five remaining patients had consistently normal serum Mg concentrations (normal-Mg group). All had normal total and ionized serum Ca. However, the total and ionized serum Ca levels in the low-Mg group were significantly lower than those of the normal-Mg group. Within 2 weeks of Mg repletion (by dialysis against 0.25 mM of Mg), the N-terminal PTH, total and ultrafiltrable serum Mg, and the total and ionized serum Ca increased in the low-Mg group. There was a strong negative correlation between initial serum Mg and the percent change in N-terminal PTH (r = 0.833) at 2 weeks for all patients. There was also a strong positive correlation between initial ionized Ca and total serum Mg for all patients (r = 0.774). Mg repletion decreased the incidence of cramps experienced during dialysis by all patients. These data suggest that Mg-free dialysis in some patients can cause Mg depletion, which is symptomatic and which may suppress the parathyroid gland.

Adult↗
PubMed1986

Hepatotoxic effects of CCl4 on English sole (Parophrys vetulus): possible indicators of liver dysfunction.

Selected serum parameters (enzyme activities and triglycerides) and liver glutathione and vitamin C concentrations were measured in English sole (Parophrys vetulus) after i.p. injection of carbon tetrachloride (CCl4), a hepatotoxin in fish. Serum lactate dehydrogenase (LDH), alkaline phosphatase (AP) and glutamate dehydrogenase (GDH) activities and the concentration of triglycerides increased in a dose-dependent manner 24 hr post injection. Concentrations of glutathione (reduced and oxidized) and ascorbic acid (vitamin C) in liver did not change in response to CCl4 toxicity 24 hr post injection. These studies indicate that serum AP activity and triglyceride concentrations can be useful in assessing the effects of CCl4-induced liver toxicity in this species of marine fish. Serum LDH and GDH activity should be used with some caution in assessing liver damage in English sole, as other tissues represent more likely sources for serum activity. The levels of liver antioxidants do not appear to be significantly affected, 24 hr post injection, by this particular hepatotoxin.

Alkaline Phosphatase↗
PubMed1981

Effect of ionized calcium and soluble magnesium on the predictability of the performance of Mueller-Hinton agar susceptibility testing of Pseudomonas aeruginosa with gentamicin.

The soluble and ionized calcium and magnesium contents of 18 lots of Mueller-Hinton agar medium from three different manufacturers were analyzed, and the results were correlated with medium performance. A standardized disk diffusion test, with Pseudomonas aeruginosa (ATCC 27853) and a 10-microgram gentamicin disk, served as an indicator of medium performance. Zone diameters correlated well with the ionized calcium values and the sum of the ionized calcium and soluble magnesium values in the different lots (r = -0.88 for both). Zone diameters correlated poorly with ionized magnesium values (r = -0.57), which were best described by a curvilinear relationship. Supplementation of lots of Mueller-Hinton agar medium with equivalent amounts of calcium and magnesium as the chloride, gluconate, or glycerophosphate salts produced identical decreases in zone sizes. Adjustment of deficient lots of Mueller-Hinton agar medium with ionized calcium or soluble magnesium or both (as the gluconate salts), to match the concentrations in lots that provided satisfactory zone sizes (17 to 19 mm), resulted in performance comparable to that of the control lots. Sixteen strains of Pseudomonas aeruginosa, ranging from resistant to susceptible, responded to cation adjustment in the same manner as the ATCC quality control strain. Satisfactory medium performance can obviously be assured by biological means in aminoglycoside susceptibility testing of Pseudomonas aeruginosa on Mueller-Hinton medium; however, cation adjustment of medium to predetermined levels of ionized calcium and soluble magnesium can now also provide desirable performance levels for P. aeruginosa on Mueller-Hinton medium.

Calcium↗
PubMed1980

Cation components of Mueller-Hinton agar affecting testing of Pseudomonas aeruginosa susceptibility to gentamicin.

Seven lots of Mueller-Hinton agar were examined for calcium and magnesium contents and their distribution in pools or compartments. Gel disruption and centrifugation yielded the soluble cations, which varied from 9 to 113% of the total calcium and from 76 to 102% of the total magnesium. Throughout the experiments, a standardized disk diffusion test, using Pseudomonas aeruginosa (ATCC 27852) and a 10-mug gentamicin disk, served as an indicator for medium performance. Zone diameters correlated well with the sums of the soluble calcium and magnesium values in the different lots (r = -0.85). Ionized calcium, presumably the biologically active ion, was measured with a calcium-specific electrode. It represented only a fraction of the soluble calcium pool in three lots. Autoclaving resulted in shifts of the cations between the different pools. Addition of magnesium to one medium lot resulted in shifts of soluble and ionized calcium, indicating an interdependence of calcium and magnesium, and zone diameters correlated with soluble magnesium (r = -0.98), soluble calcium (r = -0.96), and ionized calcium (r = -0.96) in this experiment. Manipulation of one medium to match the performance of another showed that excess amounts of both ions were required to obtain similar performance. Satisfactory performance of an individual medium can be obtained by cation supplementation, but simple adjustment will not suffice for all media. The interaction of the other cation pool components must also be evaluated.

Agar↗
PubMed1980

Hematologic response of fish to changes in gas or hydrostatic pressure.

Hematologic changes were studied in fingering salmon after rapid decompression from combined or independent exposure to gas and hydrostatic pressure. After decompression, fingerling salmon saturated with excess gas under pressure (10.1-40.6 m of seawater) suffered a decrease in thrombocyte counts and fibrinogen, prolonged prothrombin (PT) times, and increased fibrinolytic activity, plasma proteins, and erythrocyte counts in proportion to severity of the dive. After decompression, fingerling salmon exposed to increased pressure experienced an increase in thrombocyte counts and available fibrinogen, shortened PT times, increased erythrocyte counts, and decreased plasma protein levels. It appeared that pressure causes activation of the blood coagulation system of fish. This activation may predispose the fish to increased susceptibility to bubble-induced diffuse intravascular coagulation after rapid decompression. Furthermore, hemoconcentration after decompression may be a pressure-related phenomenon and not a response to bubble-induced anoxia.

Animals↗
PubMed1976

The response of fish blood cells, particularly thrombocytes, to decompression.

The effects of decompression on various blood-cell types in chinook salmon (Oncorhynchus tshawytscha) were investigated using a 4-liter hyperbaric chamber. Thrombocytes (platelets) were found to decrease significantly in numbers following lethal and nonlethal decompressions. The response was highly dependent on depth, gas solubility, and rate of decompression, whereby increasing depth or gas solubility caused greater and faster declines of thrombocyte levels. Return of thrombocyte numbers to normal values usually occurred within 48 hours, except after the more severe decompressions where recovery was never fully attained during the sampling period. Erythrocyte levels increased significantly 1 day after a severe decompression, suggesting hemoconcentration. Leucocytes appeared not to respond to decompression; they were not decreased compared to normal levels, although they were significantly decreased compared to levels of the chamber controls in the nonpressurized chamber. The results are discussed in relation to possible involvement of the fish's blood-coagulation system after decompression.

Animals↗
PubMed1975

Changes in hemostatic parameters in fish following rapid decompression.

The effect of rapid decompression on the stress-accelerated blood coagulation system of male and fingerling coho salmon (Oncorhynchus kisutch) was examined after simulated 100- and 200-fsw dives. Blood samples taken either through a dorsal aorta cannula or from a severed caudal peduncle were analyzed for total plasma protein and fibrinogen concentrations, prothrombin times (PT), and partial thromboplastin times (PTT). The effect of mild decompression (100-fsw) on the hemostatic mechanism of both adult and fingerling coho salmon indicated an alternating fibrinogen concentration, declining from normal levels 1 min after decompression, followed by an increase 10 to 15 min later with an eventual loss of fibrinogen to one half the original level an hour after decompression. Partial thromboplastin times were found to increase 10 to 15 min after decompression occurred. Prothrombin times showed an increase 1 hour after decompression in adult salmon, whereas in fingerlings, prothrombin times increased almost immediately from normal levels. The effect of severe decompression (200-fsw) showed similar trends, but at an accelerated rate. It was concluded that both mild and severe decompression activates the hemostatic mechanism of fish which may eventually result in consumption coagulopathy at a greater rate than reported for experimental mammals.

Age Factors↗
PubMedDate not supplied

From sediment bioassay to fish biomarker--connecting the dots using simple trophic relationships.

Two common problems in applying and interpreting invertebrate bioassays and fish biomarkers in sediment toxicology are the wide gap between significant effects concentrations determined by these two approaches, and a general lack of ecological context. We have devised an exposure system that is able to reconcile much of the disparity between invertebrate bioassay and fish biomarker results by incorporating realistic ecological processes based on deposit feeding and predator-prey interactions. This system relates the disturbance of interest (sediment contamination) to biologically meaningful effects in a resource of interest (marine flatfish) via a realistic contaminant vector (a deposit-feeding polychaete worm). In this pilot study, polychaetes (Armandia brevis) were exposed for 28 days to clean sediments supplemented with benzo(a)pyrene (BaP), para-para dichlorodiphenyldichloroethylene (pp'DDE), Aroclor 1254, or field sediments collected from two sites in Puget Sound, Washington, contaminated predominantly with polcyclic aromatic hydrocarbons (PAHs) or chlorinated compounds. Exposed worms were then fed live to juvenile English sole (Pleuronectes vetulus) for 10 or 12 days. At the end of the exposure period, fish were measured for length and weight, sacrificed, and preserved for either routine histopathology and immunohistochemical analysis of cytochrome P450 1A induction, or 32P post-labeling determination of hepatic PAH-DNA adducts. Growth of predatory flatfish was lower than reference in all but one of eight groups fed contaminant-exposed polychaetes; however, statistically significant reductions in growth were only observed in three of these eight groups, at least in part due to low statistical power. Juvenile sole from all contaminant-exposed groups showed increased expression of CYP1A, and fish exposed to BaP-exposed worms showed clear evidence of hepatic PAH-DNA adducts. This method allows the concurrent evaluation of sediment contamination at multiple biological and ecological levels. These results indicate that sediments determined to be nontoxic by common invertebrate bioassays may have the potential to cause adverse effects at higher trophic levels.

Animals↗