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Biomedical subjects

T D Phillips

Publications and source records attributed to T D Phillips.

At least 55 records · Page 3Linked to original sources

Developmental toxicity and structure-activity relationships of chlorophenols using human embryonic palatal mesenchymal cells.

The chlorophenols (CPs) comprise a major class of widely distributed and frequently occurring environmental contaminants. Previous studies have demonstrated the adverse effects of CPs on embryonic and fetal development. HEPM (human embryonic palatal mesenchymal) and MOT (mouse ovarian tumor) cell lines have been utilized in complementary bioassays for the detection of teratogens, but not the CPs. In this study, our objectives were 2-fold: (1) to determine if the HEPM assay could be used to complement other bioassay systems of nonhuman origin, i.e., Hydra attenuata (HA) and rat whole embryo culture (WEC), in the evaluation of the developmental toxicity of CPs, and (2) to delineate the ability of the HEPM assay to evaluate structure-activity relationships of pentachlorophenol (C5P), 2,3,4,5-tetrachlorophenol (C4P), 2,3,5-trichlorophenol (C3P), 3,5-dichlorophenol (C2P), 4-monochlorophenol (CP), phenol, and CP derivatives (i.e., acetates, sodium phenates and anisoles). HEPM cells were seeded into each well of a 24-well plate and cultivated for 24 h. The medium was replaced with fresh medium containing various concentrations of test chemicals dissolved in dimethyl sulfoxide (DMSO, 0.1%). After culturing for 72 h, the medium was removed, cells were trypsinized, and cell number determined. The HEPM cell growth inhibition assay demonstrated a linear relationship between the IC50 values of the CPs and degree of chlorine substitution. The IC50 values of C5P, C4P, C3P, C2P, CP, and phenol were 18.8, 21.5, 27.5, 63.0, 150.0 and 470.0 microM, respectively. A clear structure-activity relationship was observed between toxicity of CPs and the degree of chlorine substitution. The rank order of CP toxicity from the HEPM assay (i.e., C5P > C4P > C3P > C2P > CP > phenol) is in excellent agreement with previous in vitro and in vivo studies. However, contrary to published reports, the HEPM assay predicted that all CPs were teratogenic (false positives). These findings suggest that the HEPM cell growth inhibition bioassay may be useful to discriminate between subtle differences in structure-activity and, in combination with other bioassays, might facilitate the rapid detection and prioritization of diverse cytotoxins, including various developmental toxicants. Importantly, conclusions about the teratogenicity of a test chemical (via HEPM testing) should be approached with caution and confirmed with other teratogen-sensitive systems.

Animals↗

Influence of a hydrated sodium calcium aluminosilicate and virginiamycin on aflatoxicosis in broiler chicks.

Male broiler chicks were fed diets containing 0 or 3.5 mg aflatoxin (AF)/kg from 1 to 28 d of age. The diets were amended with either .5% hydrated sodium calcium aluminosilicate (HSCAS), 16.5 mg virginiamycin (VM)/kg of diet, or .5% HSCAS + 16.5 mg VM/kg of diet to determine the effects of these compounds during aflatoxicosis. When compared with controls (814 g), BW gains were significantly lower for broilers fed the AF (731 g) or AF+VM (716 g) diets. No differences were found between the BW gains of chicks fed diets without aflatoxin (814 g) and those of chicks fed AF+HSCAS (793 g) or AF+HSCAS+VM (803 g), indicating approximately 75% protection against decreased BW gain by HSCAS and 87% protection by the HSCAS+VM combination. Relative weights of the liver and kidney and creatine kinase activity were significantly increased and albumin, total protein, cholesterol, uric acid, and inorganic phosphorus concentrations were decreased in chicks fed the diet containing AF alone. With the exception of albumin, HSCAS was effective in restoring these values to control values. The findings of this research suggest that HSCAS and HSCAS+VM can counteract some of the toxic effects of AF in growing broiler chicks.

Aluminum Silicates↗

Comparison of two hydrated sodium calcium aluminosilicate compounds to experimentally protect growing barrows from aflatoxicosis.

Two formulations of hydrated sodium calcium aluminosilicate (HSCAS-1 and HSCAS-3), anti-caking agents for mixed feed, were added to the diets of growing barrows and were evaluated for their potential to diminish the clinical signs of aflatoxicosis. The experimental design consisted of 8 barrows (2 replicates of 4 each/treatment) assigned to 1 of the following 6 treatment diets (total of 48): 1) 0 g of HSCAS-1 or HSCAS-3 and 0 mg of aflatoxin (AF)/kg of feed (control); 2) 5 g HSCAS-1/kg of feed; 3) 5 g HSCAS-3/kg of feed; 4) 3 mg AF/kg of feed; 5) 3 mg AF plus 5 g HSCAS-1/kg of feed; or 6) 3 mg AF plus 5 g HSCAS-3/kg of feed. Barrows were maintained in indoor concrete-floored pens, with feed and water available for 28 days (from 8 to 12 weeks of age). Barrows were observed twice daily and weighed weekly, and blood samples were collected at day 28 for hematologic, immunologic, and serum biochemical measurements. At the termination of the study, barrows were euthanized and necropsied. Barrow body weight gains were diminished, compared to those of controls, by consumption of AF alone and both of the AF plus HSCAS diets; however, the AF plus HSCAS-1 and AF plus HSCAS-3 barrow body weight gains were significantly greater (P < 0.05) than those of the AF-alone barrows.(ABSTRACT TRUNCATED AT 250 WORDS)

Aflatoxins↗

Dietary hydrated sodium calcium aluminosilicate reduction of aflatoxin M1 residue in dairy goat milk and effects on milk production and components.

Lactating dairy goats were exposed to aflatoxin (100 and 200 ppb) and hydrated sodium calcium aluminosilicate at 1, 2, and 4% in two separate experiments. Naturally occurring low levels of aflatoxin M1 (.009 ppb) were found in the milk of the control diet, whereas there were no detectable levels of aflatoxin M1 in the milk of diets containing hydrated sodium calcium aluminosilicate in both experiments. In Exp. 1, no treatment-related differences in clinical behavior or significant difference in the feed intake, milk production, or milk component analyses were observed with 200 ppb of aflatoxin and 4% hydrated sodium calcium aluminosilicate. However, 4% hydrated sodium calcium aluminosilicate was responsible for an 86.9% reduction of aflatoxin M1 residue in the milk of diary goats. In Exp. 2, the combination of 1% hydrated sodium calcium aluminosilicate and aflatoxin at 100 ppb resulted in an overall reduction of aflatoxin M1 residue by 51.9%, which represented a mean change of aflatoxin M1 from .553 to .266 ppb of aflatoxin M1 in the milk. The diet that contained 2% hydrated sodium calcium aluminosilicate and 100 ppb of aflatoxin further reduced aflatoxin residue by a mean change from .553 to .098 of ppb aflatoxin M1, which represents an 82.2% reduction of aflatoxin M1 residue in the milk. Analysis of the data by time indicated that there were no statistical differences between days of sampling. Information regarding the ability of hydrated sodium calcium aluminosilicate to prevent or reduce the level of aflatoxin M1 residues in milk is critically needed.(ABSTRACT TRUNCATED AT 250 WORDS)

Aflatoxin M1↗

Development and evaluation of a minicolumn assay for the detection of aflatoxin M1 in milk.

A practical field method for the chemiselective immobilization and detection of aflatoxin M1 in milk has been developed and is being marketed. In this new method, aflatoxin M1 is selectively adsorbed at the interface of a layer of neutral sand and a band of magnesium silicate (Florisil) packed in a glass minicolumn. Aflatoxin M1, at > or = .5 ppb in contaminated milk, can be easily visualized as a band of bright blue fluorescence. Briefly, raw or homogenized and pasteurized milk is diluted with water (1: 1, vol/vol) and passed through a C18 cartridge. Aflatoxin M1 is then partitioned by polarity, eluted with acetone-methylene chloride, and added to the minicolumn. The minicolumn is washed and viewed under long wave UV light. The limit of detection for this assay was .2 ppb, which was similar to the .3 ppb obtained using an immunoaffinity column, followed by minicolumn detection. The assay was accurate, rapid, easy to perform, and stable.

Adsorption↗

Individual and combined toxicity of T-2 toxin and cyclopiazonic acid in broiler chicks.

The effects of feeding 6 mg T-2 toxin (T-2) and 34 mg cyclopiazonic acid (CPA)/kg of diet singly and in combination were characterized in male broiler chicks from 1 d to 3 wk of age. Body weights were depressed by T-2, CPA, and the combination of T-2 and CPA. There was a significant synergistic interaction between T-2 and CPA for relative liver and kidney weights and serum cholesterol and triglyceride concentrations and a significant interaction between T-2 and CPA for 3-wk body weights and relative bursa of Fabricius weights, which were less than additive. Neither the efficiency of feed utilization nor mortality was affected by dietary treatments. Oral lesions were present in a majority of the chicks fed diets containing T-2 with or without CPA. When compared with controls, other variables measured exhibited additive or less than additive toxicity. These data demonstrate that T-2 and CPA alone and in combination can cause reduced performance and adversely affect broiler health. The effects of these mycotoxins may be exacerbated by other factors when under field conditions; hence, the potential detrimental effects of these two mycotoxins when present alone or in combination cannot be dismissed.

Animals↗

Evaluation of the developmental toxicity of citrinin using Hydra attenuata and postimplantation rat whole embryo culture.

Citrinin (a mycotoxin produced as a frequent contaminant of food and feed by numerous species of Aspergillus and Penicillium fungi) is embryo/fetotoxic and embryocidal in mice and rats. The present study was designed to examine whether the in vivo observed developmental toxicity of citrinin could be recapitulated using the Hydra attenuata (HA) bioassay and then be confirmed in rat whole embryo culture (WEC). Results from the HA assay indicated that the minimal affective concentrations of citrinin required to elicit a toxic response in the adult hydra (MACA) and in the regenerating hydra (MACD) were 30 mg/l and 20 mg/l, respectively. The Hydra developmental hazard index (A/D ratio) was equal to 1.5, classifying citrinin as a coaffective developmental toxin. In WEC, rat embryos were cultured in homologous (rat) serum containing citrinin at various concentrations ranging from 0.0 and 300 micrograms/ml for a period of 45 h. The results indicated a concentration-dependent reduction in yolk sac diameter, crown-rump length, somite number, protein and DNA contents. No embryonic dysmorphogenesis was observed in any treatment group. Histological examination revealed severe diffuse mesodermal and ectodermal necrosis in embryos treated with 250 micrograms/ml citrinin. At lower concentrations of citrinin, embryos were neither grossly nor histologically different from controls. Both the HA and WEC bioassays demonstrated that citrinin is not a primary developmental toxin. The use of HA and WEC bioassays in tandem may facilitate the rapid detection and ranking of the developmental hazards of food and feedborne mycotoxins.

Animals↗

Teratogenicity and immunotoxicity of 3,3',4,4',5-pentachlorobiphenyl in C57BL/6 mice.

Administration of 3,3',4,4',5-pentachlorobiphenyl (pentaCB) to female C57BL/6 mice at doses from 130.5 to 522 micrograms/kg body weight resulted in the dose-dependent formation of fetal cleft palate and hydronephrosis. The estimated relative potency of 3,3',4,4',5-pentaCB compared to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was in the range of < 0.07-0.04. The immunotoxicity of 3,3',4,4',5-pentaCB and two structurally-related congeners, 3,3',4,4'-tetraCB and 3,3',4,4',5,5'-hexaCB, was investigated in male C57BL/6 mice by determining their suppression of the splenic plaque-forming cell response to sheep red blood cells. The potencies of these compounds relative to TCDD were determined from the ratios of their corresponding ED50 values and were 0.77-0.55 (3,3',4,4',5-pentaCB), 1.1-0.29 (3,3',4,4',5,5'-hexaCB) and 0.14-0.03 (3,3',4,4'-tetraCB). These results demonstrate that the immunosuppressive activities of the PCB congeners relative to TCDD were much higher than observed for many other TCDD-like responses in mice and other laboratory animals.

Abnormalities, Drug-Induced↗

Evaluation of aluminosilicate compounds to reduce aflatoxin residues and toxicity to poultry and livestock: a review report.

The aflatoxins (AFs) are reported to be hepatotoxic, mutagenic, immunosuppressive, and carcinogenic. Methods to prevent, reduce, or remediate AF toxicity and residues in the environment are in great demand. Various AF-detoxification procedures are reviewed with particular emphasis on ammoniation and the use of adsorbent compounds to bind AF. A series of in vivo experiments by the authors are reviewed that evaluated the ability of a specific hydrated sodium calcium aluminosilicate (HSCAS) adsorbent to reduce the toxicity of AF to poultry and livestock and to reduce AF residues in milk. These studies showed that HSCAS forms stable bonds with AF in vitro, and when added to AF-contaminated poultry and livestock feeds, HSCAS is able to protect chickens, swine, and lambs from the deleterious toxic effects of AF and to reduce AF residues in milk of dairy cows and goats. These results indicate that HSCAS, when used in conjunction with other mycotoxin management practices, may prove effective for the preventive management of AF-contaminated feedstuffs in livestock and poultry and may reduce AF residues in the food-chain.

Adsorption↗

Efficacy of a hydrated sodium calcium aluminosilicate to reduce the toxicity of aflatoxin and diacetoxyscirpenol.

A hydrated sodium calcium aluminosilicate (HSCAS) was incorporated into diets (.5%) containing 3.5 mg/kg aflatoxin (AF) and 5.0 mg/kg diacetoxyscirpenol (DAS) singly and in combination. Male broiler chicks received ad libitum access to their respective diets and water from 1 to 21 days of age. Body weight gains were significantly (P < .05) depressed by AF and DAS singly and a synergistic interaction occurred between AF and DAS for a further depression of body weight gains. Alterations in hematological and serum biochemical values, as well as serum enzyme activities, were observed for the AF and the AF and DAS combination. Additionally, a significant interaction occurred between AF and DAS for some biochemical values and enzyme activities. Adding HSCAS resulted in almost total protection against the effects caused by AF alone, limited protection against the combination, but no protection against the DAS alone. These findings indicate that HSCAS can diminish the adverse effects of AF but not of DAS.

Aflatoxins↗

Effect of hydrated sodium calcium aluminosilicates on aflatoxicosis in broiler chicks.

In three experiments, three different hydrated sodium calcium aluminosilicates (HSCAS) were incorporated into chick diets (.5%) containing either 0 or 5.0 (Experiments 1 and 2) or 0 or 2.5 (Experiment 3) mg/kg aflatoxin (AF). Male broiler chicks consumed their respective diets and water ad libitum from 1 to 21 days of age. When compared with controls, body weights in chicks receiving 5.0 mg AF/kg were reduced by 214 g in Experiment 1 and 220 g in Experiment 2. The addition of .5% of the HSCAS compounds significantly diminished the growth inhibitory effects caused by AF by 39 to 68% in Experiment 1, by 46 to 88% in Experiment 2, and by 38 to 90% in Experiment 3. The increases in relative organ weights and the decreases in serum biochemical values caused by AF were significantly diminished to differing degrees by all three of the HSCAS compounds. These data demonstrate that these specific HSCAS compounds can be protective against the effects of AF in young growing broilers and further emphasizes the fact that all silicate-type sorbents are not equal in their ability to protect against aflatoxicosis. It also seems possible to specially process compounds to increase their efficacy for protection against the toxicity of AF.

Aflatoxins↗

Patulin-induced cellular toxicity: a vital fluorescence study.

The mechanisms of patulin-induced cellular toxicity in an immortalized rat granulosa cell line were examined using several vital fluorescence bioassays. Monochlorobimane and 5-chloromethylfluorescein diacetate were used to monitor cellular glutathione (GSH) levels and revealed dose- and time-dependent depletion of GSH by patulin. A significant reduction in the fluorescence of the monochlorobimane-GSH conjugate by 0.1 microM patulin was observed between 1 and 2 hr. Similar GSH depletion by the mycotoxin was also observed in parallel studies on a liver (Clone 9) and a renal (LLC-PK1) cell line, although reduction of fluorescence occurred within 1 hr at the same dosage. Analysis of the electrical potential-dependent partitioning of rhodamine 123 into mitochondria also revealed significant effects of patulin within 1 hr at 0.1 microM. An initial dose-dependent reduction in mitochondrial fluorescence was followed by loss of selective partitioning of the fluorophore into mitochondria at higher doses and/or a longer exposure of cells to patulin. The reduction in mitochondrial fluorescence was paralleled by a dose-dependent decrease in intracellular pH detected with 2',7'-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein. Analysis of [Ca2+]i with indo-1 and fluo-3 revealed a significant dose-dependent influx of Ca2+ at 10 microM and an alteration of the pattern of ionomycin-induced Ca2+ influx at 1.0 microM following patulin treatment. A carboxyfluorescein fluorescence photobleaching assay was used to examine the effects of patulin on gap junction-mediated intercellular communication. Dose-dependent reduction in intercellular communication was observed within 2 hr with 1.0 microM patulin. These observations indicate that the fluorescence assays used in this study provide a sensitive index of toxicity caused by exposure to patulin. Further, the toxic effects of patulin may involve direct effects on cellular glutathione levels and mitochondrial function in addition to direct effects on the plasma membrane.

Animals↗

Efficacy of hydrated sodium calcium aluminosilicate to reduce the individual and combined toxicity of aflatoxin and ochratoxin A.

A 2 x 2 x 2 factorial arrangement of treatments consisting of dietary aflatoxin (3.5 micrograms/g), ochratoxin A (2.0 micrograms/g), and hydrated sodium calcium aluminosilicate (HSCAS, .5%) was used to evaluate the individual and combined effects of these treatments. There were six replicate pens of 10 broilers per pen for each of the eight treatments. The broilers were maintained on these treatments from 1 day to 3 wk of age with feed and water available for ad libitum intake. Aflatoxin and ochratoxin A each significantly decreased body weight, serum protein, albumin, and cholesterol and increased the relative weight of the liver, kidney, and proventriculus. Aflatoxin increased the relative weight of the heart and decreased serum aspartate aminotransferase activity and ochratoxin A increased serum uric acid. The toxicity resulting from the combination of aflatoxin and ochratoxin A was more severe than when either of these mycotoxins were present alone. Addition of HSCAS alone did not alter any of the parameters evaluated. The HSCAS reduced the toxicity of aflatoxin, but had little effect on either the toxicity of ochratoxin A alone or the toxicity resulting from the combination of aflatoxin and ochratoxin A.

Aluminum Silicates↗

Toxicological evaluation of aflatoxin and cyclopiazonic acid in broiler chickens.

The individual and combined effects of aflatoxin (AF) and cyclopiazonic acid (CPA) were evaluated in day-old Petersen x Hubbard broiler chickens to 3 wk of age. Treatments were arranged in a 2 x 2 factorial with levels of 0 and 3.5 mg AF/kg of feed, and 0 and 50 mg CPA/kg of feed. Production performance, serum biochemistry, and gross pathological observations were evaluated. Body weight gain was significantly (P less than .05) reduced by AF, CPA, and the AF-CPA combination at the end of 3 wk. Aflatoxin significantly increased the relative weight of the kidney and serum concentration of blood urea nitrogen and decreased serum concentrations of protein, albumin, cholesterol, phosphorus, and the activity of lactate dehydrogenase. The toxicity of CPA was expressed through increased relative weights of the liver, kidney, and proventriculus, increased levels of uric acid and cholesterol, and decreased serum phosphorus. The activity of AF-CPA combination was characterized by increased relative weight of the liver, kidney, pancreas, and proventriculus, decreased concentrations of serum albumin and phosphorus, increased concentrations of serum glutamic oxalacetic transaminase and blood urea nitrogen, and decreases in the relative weight of the bursa of Fabricius. Post-mortem examination revealed that the chickens fed CPA and the AF-CPA combination had thickened mucosa and dilated proventricular lumens, hard fibrotic spleen, and atrophy of the gizzard. The data from the present study demonstrate that both AF and CPA alone and the AF-CPA combination can limit broiler performance and adversely affect broiler health. In most cases the effects of AF and CPA were additive.

Aflatoxins↗

Evaluation of the developmental toxicity of chlorinated phenols utilizing Hydra attenuata and postimplantation rat embryos in culture.

Chlorinated phenols (CPs) represent a major component of hazardous oily and wood-preserving wastes that are widely distributed in chemical dumpsites throughout the United States. Pentachlorophenol (C5P) has been reported to be highly embryolethal and embryotoxic in rats. However, data pertaining to the developmental toxicities of other important CPs are limited. In this study, the toxicities of phenol, CP homologues and their isomers, selected phenyl acetates, anisoles, sodium phenates, and tetrachlorobenzoquinones (a total of 38 chemicals) were evaluated using cultures of Hydra attenuata (HA). Developmental hazard index (A/D ratio) was determined for selected test chemicals (i.e., those chemicals which resulted in an early toxic endpoint at the lowest whole-log concentration in the adult hydra assay). These same chemicals were evaluated at equimolar concentration in postimplantation rat whole embryo culture (WEC). HA and WEC studies demonstrated a linear relationship between toxicity and the degree of chlorine substitution with C5P greater than 2,3,4,5-C4P greater than 2,3,5-C3P greater than 3,5-C2P greater than 4-CP greater than phenol. The A/D ratios from the HA assay were approximately 1 for all of the chemicals tested. Findings from the WEC assay indicated similar results based on growth, gross morphology, and DNA and protein content of embryos. The results obtained in the HA and WEC assays suggest that the chlorinated phenols are not potent teratogens. The combination of HA and WEC may facilitate the rapid detection and ranking of hazardous chemicals associated with complex mixtures of chemical wastes.

Animals↗

Effects of a hydrated sodium calcium aluminosilicate on growing turkey poults during aflatoxicosis.

Effects of adding .5% of a hydrated sodium calcium aluminosilicate (HSCAS) to diets containing 1 or .5 mg aflatoxin (AF)/kg were determined in male turkey poults from 1 day to 3 wk of age. Body weight gains were significantly reduced by 51 and 19% in turkey poults fed 1 and .5 mg AF/kg, respectively; efficiency of feed utilization was not affected. There were no deaths in poults fed .5 mg AF/kg; however, the mortality rate was 88% in poults fed 1 mg AF/kg. The addition of .5% dietary HSCAS resulted in a 68% decrease in mortality to 28% for the 3-wk experimental period. Treatment-related changes in relative organ weights, hematological values, serum biochemical values, and enzyme activities were observed. The HSCAS in the absence of AF did not alter any of the parameters measured. The HSCAS diminished the adverse effects of AF on body weight gains, most relative organ weights, hematological values, serum biochemical values, and enzyme activities associated with .5 mg AF/kg, but not 1 mg AF/kg. These findings indicate that HSCAS may diminish many of the adverse effects of AF in an AF-sensitive species, the turkey.

Aluminum Silicates↗

Effects on aflatoxin M1 residues in milk by addition of hydrated sodium calcium aluminosilicate to aflatoxin-contaminated diets of dairy cows.

Hydrated sodium calcium aluminosilicate (HSCAS), an anticaking agent for agricultural feeds, was added to aflatoxin (AF)-contaminated diets of 3 lactating dairy cows and evaluated for its potential to reduce aflatoxin M1 (AFM1) residues in milk. During phase I, cows were fed alternating diets that consisted of 200 micrograms of AF/kg of feed for 7 days, 0.5% HSCAS plus 200 micrograms of AF/kg of feed for 7 days, and feed with the HSCAS removed for a final 7 days. The AFM1 milk concentrations from the intervals with HSCAS added to diets were compared with those times when HSCAS was absent. The presence of 0.5% HSCAS in feed containing 200 micrograms of AF/kg reduced AFM1 secretion into the milk by an average of 0.44 micrograms/L (from pretreatment of 1.85 micrograms/L to 1.41 micrograms/L with HSCAS, a 24% reduction). Following a 10-day period of noncontaminated feed consumption and no AFM1 residues in the milk, phase II of the study was begun. The same experimental design as phase I was used, but the dosages of HSCAS and AF were changed to 1.0% and 100 micrograms/kg of feed, respectively. The addition of 1.0% HSCAS in feed containing 100 micrograms of AF/kg decreased AFM1 content in the milk by an average of 0.40 micrograms/L (from a pretreatment of 0.91 micrograms/L to 0.51 micrograms/L when HSCAS was present, a 44% reduction). These findings suggest that HSCAS, a high-affinity sorbent compound for AF in vitro, is capable of reducing the secretion of AFM1 into milk.

Aflatoxin M1↗