In vitro susceptibility of mycelial and yeast forms of Penicillium marneffei to amphotericin B,fluconazole, 5-fluorocytosine and itraconazole

The mycelial (25°C) and yeast-like (37°C) forms of Penicillium marneffei clinical and type strains were investigated for their in vitro susceptibility to amphotericin B (AmB), 5-fluorocytosine (5-FC), fluconazole (FLU) and itraconazole (ITZ), using Bacto antibiotic medium 3, yeast-nitrogen, Sabouraud's dextrose (pH 5.7) and high resolution (pH 7.1) broth media (1ml/tube), respectively. Results indicated that the minimal inhibitory and minimal fungicidal concentrations (MICs and MFCs) for the mycelial cultures of P. marneffei to AmB were in the range 0.78–1.56 and 0.78–3.125 g/ml, respectively, as against 3.125–25 g (MICs) for the yeast form cultures. The MFCs to AmB for the yeast form were one dilution higher. The MICs to FLU were generally lower for the yeast form (6.25–25 g) than the mycelial form (25–50 g/ml), whereas MFCs for the mycelial cultures were > 100 g as compared to 6.25–100 g for their yeast form. The MICs for the mycelial form to 5-FC ranged from < 0.195–0.39 g. Higher MICs (6.25 g) were recorded for their yeast form. The MFCs to 5-FC for the yeast form were 25–100 g/ml. The MICs for the mycelial form to ITZ ranged from < 0.195 to 3.125 g/ml. Higher values (< 0.195–50 g) were recorded for their yeast-like form. The MFCs to ITZ for mycelial and yeast forms ranged from < 0.195–0.39 and 25–100 g/ml, respectively. Results indicate that P. marnefei's yeast form is more sensitive to FLU and ITZ (8 of 10 strains) while the mycelial form displayed greater susceptibility to AmB and 5-FC. The MICs for ITZ remained steady in SD medium, pH 5.7 to 7.1. However, some strains gave higher MIC values (0.39–1.56 g/ml) when tested in the HR.     

Blood styrene concentrations in a “normal” population and in exposed workers 16 hours after the end of the workshift

Summary Blood styrene was measured by a gas chromatography-mass spectrometry method in 81 normal people and in 76 workers exposed to styrene. In the normal subjects, styrene was also tested in alveolar and environmental air. Styrene was found in nearly all (95%) blood samples. Average styrene levels in the normal subjects were 221 ng/1 in blood (Cb), 3 ng/1 in alveolar air (Ca) and 6 ng/1 in environmental air (Ci). Styrene levels did not differ significantly between smokers and non-smokers, 95% of values being below 512 ng/1 in Cb, 7 ng/1 in Ca and 15 ng/l in Ci. In workers with an average exposure to styrene of 204 g/l, at the end of the workshift, mean blood styrene concentration was 1211 g/l. In blood samples collected at the end of the Thursday shift, styrene levels were significantly higher (1590 g/1) than those found at the end of the Monday shift (1068 g/l. A similar difference was found in samples taken the morning after exposure (60 and 119 g/l, respectively). Significant correlations between blood and environmental styrene were found both at the end of the shift and the morning after exposure (r=0.61 and 0.41, respectively). In workers occupationally exposed to styrene, 16 h after the end of the workshift, blood styrene (94 g/l) was significantly higher than that found in the normal subjects (0.22 g/l). The half-life of blood styrene was 3.9 h.     

Occupational chronic exposure to metals

Summary External and internal chromate exposure of 103 stainless steel welders who were using manual metal arc welding (MMA), metal inert gas welding (MIG) and both methods, were measured by ambient and biological monitoring. At the working places the maximum chromium trioxide concentrations were 80 g/m³. The median values were 4 g/m³ (MMA) and 10 g/m³ (MIG). The median chromium concentrations in erythrocytes, plasma and urine of all welders were < 0.60, 9.00 and 32.50 g/l. For biological monitoring purposes, chromium levels in erythrocytes and simultaneously in plasma seem to be suitable parameters. According to our results, chromium levels in plasma and urine in the order of 10 and 40 g/l seem to correspond to an external exposure of 100 g chromium trioxide per cubic metre, the technical guiding concentration (TRK-value). Chromium concentrations in erythrocytes greater than 0.60 g/l indicate an external chromate exposure greater than the TRK-value.     

Accumulation of Selenium and Lack of Severe Effects on Productivity of American Dippers (Cinclus mexicanus) and Spotted Sandpipers (Actitis macularia)

Selenium has been found at elevated concentrations in water, sediments, and aquatic biota in the Elk River (British Columbia, Canada) and some of its tributaries downstream of several coal mines. Selenium water concentrations in those areas exceed Canadian and British Columbia guidelines and are above levels at which adverse effects to fish and waterfowl could occur. We compared selenium concentrations in the eggs of two riverine waterbirds, American dippers and spotted sandpipers, with measures of productivity: the number of eggs laid, egg hatchability, and nestling survival. In American dippers, the mean egg selenium concentration from the exposed areas, 1.10±SE 0.059 g/g wet weight, was indistinguishable from the reference areas, 0.96±SE 0.059 g/g wet weight. For spotted sandpipers, the mean egg selenium concentration in the exposed areas, 2.2±0.5 g/g wet weight, was significantly higher than in the reference areas, 1.2±0.14 g/g wet weight, but less than reported thresholds for waterfowl and other shorebirds. There were no significant differences in egg hatchability between dippers in reference and exposed areas, but reduced hatchability was apparent for sandpipers in exposed locations. Despite the slightly reduced hatchability in sandpipers, overall productivity was higher than regional norms for both species; thus, selenium did not affect the number of young recruited to local populations. We did not observe teratogenic effects in either species, although none was expected at these concentrations. Despite moderately high selenium concentrations in the water, mean egg selenium concentrations were less than predicted from uptake models. We hypothesise that the relatively low uptake of selenium into the eggs of the two waterbirds in this study is likely due to their lotic environments low biological transformation and uptake rates.     

Sublethal Effects of Trace Metals (Cd,Cr, Cu,Hg) on Embryogenesis and Larval Settlement of the Ascidian <Emphasis Type="Italic">Ciona intestinalis</Emphasis>

Toxicity of Cadmium (Cd), Chromium (Cr), Copper (Cu), and Mercury (Hg) on the early developmental stages of Ciona intestinalis was investigated. Developmental defects of larvae after exposure of gametes throughout their development to the larval stage were assessed. Gamete exposure to increasing metal concentrations resulted in a significant decrease of the percentage of normally hatched larvae, showing median effective concentrations (EC₅₀) of 721 g/L (6.42 M) for Cd, 12772 g/L (226 M) for Cr, 36.6 g/L (0.576 M) for Cu, and 44.7 g/L (0.223 M) for Hg. Larval attachment was significantly affected when gametes were exposed to the metals throughout development. The EC₅₀ reducing larval attachment by 50% were 752 g/L (6.7 M) for Cd, 15026 g/L (289 M) for Cr, 67.8 g/L (1.607 M) for Cu, and 78.1 g/L (0.389 M) for Hg. Therefore, on a molar basis Hg is three times more toxic than Cu, 20–30 times more than Cd, and 700–1000 times more toxic than Cr, for both responses.     

Biological monitoring of isocyanates and related amines

Summary Five men were exposed to toluene diisocyanate (TDI) atmospheres for 7.5 h. The TDI atmospheres were generated by a gas-phase permeation method, and the exposures were performed in an 8-m3 stainless-steel test chamber. The mean air concentration of TDI was ca. 40 g/m³, which corresponds to the threshold limit value (TLV) of Sweden. The inhaled doses of 2,4- and 2,6-TDI were ca. 120 g. TDI in the test chamber air was determined by an HPLC method using the 9-(N-methyl-aminomethyl)-anthracene reagent and by a continuous-monitoring filter-tape instrument. After hydrolysis of plasma and urine, the related amines, 2,4- and 2,6-toluenediamine 2,4-, and 2,6-TDA), were determined as pentafluoropropionic anhydride (PFPA) derivatives by capillary gas-chromatography using selected ion monitoring (SIM) in the electron-impact mode. The urinary elimination of the TDAs showed a possible biphasic pattern, with rapid first phases for 2,4-TDA (mean t _1/2 for the concentration in urine, 1.9 h) and for 2,6-TDA (mean t _1/2 for the concentration in urine, 1.6 h). The cumulative amount of 2,4-TDA excreted in urine within 28 h ranged from 8% to 14% of the estimated dose of 2,4-TDI, and the cumulative amount of 2,6-TDA in urine ranged from 14% to 18% of the 2,6-TDI dose. The average urinary level of 2,4-TDA was 5 g/l in the 6 to 8-h sample (range 2.8–9.6 g/l), and the corresponding value for 2,6-TDA was 8.6 g/l (range, 5.6–16.6 g/l). Biological monitoring of exposure to 2,4- and 2,6-TDI by analysis of 2,4- and 2,6-TDA in urine is feasible.     

Blood toluene as a biological index of environmental toluene exposure in the “normal” population and in occupationally exposed workers immediately after exposure and 16 hours later

Blood toluene was measured in a group of 100 workers occupationally exposed to a mean 8-h environmental toluene concentration of 128 g/l (34 ppm), and in a group of 269 normal subjects without occupational exposure to toluene. The mean blood toluene of the workers at the end of the shift and the following morning, after 16 h, was 457 and 38 g/l, respectively. The normal subjects had a blood toluene level of 1.1 g/l. On the basis of the highly significant correlation between blood toluene and occupational exposure, it can be calculated that environmental toluene exposure of 188 and 377 g/l (50 and 100 ppm) gives end-of-shift blood toluene levels of 690 and 1390 g/l, respectively. The corresponding blood toluene levels on the following morning are 50 and 100 /l, respectively.     

The acute and chronic effects of cadmium on the estuarine mysid,Mysidopsis bahia

Summary Mysids, small shrimp-like Crustacea, proved to be a practical bioassay animal for investigating the effects of cadmium in seawater and may serve this purpose for other pollutants. In the laboratory under flow-through test conditions, the mysid,Mysidopsis bahia, was more sensitive to cadmium than other crustaceans tested. LC50 values were 15.5 g/ within 96 hrs and 11.3 g/ during a 17-day life cycle, whereas LC50's for other selected crustaceans were between 120 and 720 g/. Results of life-cycle bioassays can aid in the establishment of water quality criteria for marine and estuarine organisms.     

Placental transfer of lead,mercury and cadmium in women living in a rural area

Summary The influence of the lead content of drinking water on the transplacental transfer of lead was investigated in 70 pregnant women living in a rural area of Belgium. The mothers were divided into 2 groups: group A: morning water lead below 50 g/liter; group B: morning water lead above this value. In group A, the mean lead content of water was 11.8 g/liter and in group B it amounted to 247.4 g/liter.The difference in the mean lead concentration between the two groups were for maternal blood: 3.2 g/100 ml, for umbilical cord blood: 3.3 g/100 ml, and for placenta: 3.6 g/100 g. These differences are statistically significant.There were significant correlations between water lead and lead concentration in blood (mother, newborn) or placenta. An increment of water lead concentration from 50 to 500 g/liter increases blood lead concentration in mother and in newborn by about 3 g/100 ml and in placenta by about 2.5 g/100 g (wet weight).     

Biological assessment of exposure to antimony and lead in the glass-producing industry

Summary The oxide of trivalent antimony is used in the glass-producing industry as a refining agent and as a glass colouring. The batch contains up to 2% Sb₂O₃, a substance which has shown carcinogenic properties in animal experiments. The internal levels of antimony and lead in blood (SbB and PbB) as well as the excretion with the urine (SbU and PbU) were determined by hydrid and electrothermal atomic absorption (HY-AAS and ET-AAS), respectively. In addition, measurements of airborne Sb₂O₃-concentrations were performed. The 109 volunteers were employed in four different fields: melting area, batch bunker, glass-washing area, and transport/maintenance. Differences between the concentrations of antimony and lead in blood and urine with respect to the fields of activity were evaluated statistically. The highest values of airborne Sb₂O₃ with up to 840 g/m³ (TWA), were detected in the batch bunker. Correspondingly, significantly enhanced SbU-values from 1.5 to 15.7 g/l (median: 5.0 g/l were found in specimens collected from the batch mixers. In the same group, the lead excretion (PbU) with values from 9 to 110 g/l (median: 43 g/l) was also found to be the highest. Due to the fast renal excretion of antimony, the determination of SbU is useful for biological monitoring.     

Lead exposure in indoor firing ranges

Summary Higher air lead levels (time-weighted average 660, range 112–2238 g/m³) were measured in firing ranges where powder charges were employed than in ranges where air guns were used (4.6, range 1.8–7.2 g/m³); levels in the latter were in turn higher than those in ranges used for archery (0.11, range 0.10–0.13 g/m³) Twenty-two marksmen who used powder charges had significantly increased blood lead levels during the indoor shooting season (before: median 106, range 32–176 g/l; after: 138; range 69–288 g/l; P = 0.0001), while 21 subjects who mainly used air guns displayed no significant increase (before: median 91, range 47–179 g/l; after: 84; range 20–222 g/l). Thirteen archers had significantly lower levels than the pistol shooters before the season (P = 0.006), and showed a significant decrease during the season (before: median 61, range 27–92 g/l; after: 56; range 31–87 g/l; P = 0.04). At the end of the indoor season, there was a significant association between weekly pistol shooting time and blood lead levels.     

Effects of 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) injected into the yolks of chicken (Gallus domesticus) eggs prior to incubation

The yolks of White Leghorn chicken (Gallus domesticus) eggs were injected prior to incubation with either 3,3,4,4,5- pentachlorobiphenyl (PCB 126) at doses ranging from 0.1 to 12.8 g/kg egg or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) at doses ranging from 0.04 to 0.64 g/kg egg. Chicks were subjected to necropsy within 24 h of hatching. The brain, bursa, heart, liver, and spleen were removed and weighed. Assessment of the rate of hatching indicated an LD₅₀±S.E. of 2.3±0.19 g/kg egg (7.1±0.58 nmol/kg egg) for PCB 126 and 0.15±0.012 g/kg egg (0.47±0.037 nmol/kg egg) for TCDD. No significant differences in the incidence of developmental abnormalities (structural defects and edema) were observed in TCDD-exposed embryos, while PCB 126 caused significantly more developmental abnormalities at 3.2, 6.4, and 12.8 g/kg egg than the vehicle control. PCB 126 caused lower hatchling weights and greater relative brain, heart, and liver weights when compared to the vehicle control group at a dose of 3.2 g/kg egg which is greater than the LD₅₀. TCDD at 0.08 g/kg egg caused relative bursa weights to be less than those of the vehicle control. A toxic equivalency factor (TEF) of 0.07 was determined for PCB 126 in relation to TCDD based on overt lethality.     

Acute and chronic exposure of Dunaliella salina and Chlamydomonas bullosa to copper and cadmium: Effects on growth

Effective copper and cadmium concentrations which limited the growth of two chlorophytes by 50%, EC(50)s, after 96 h of static exposure were determined. EC(50)s were 5.94 gM copper and 4.55 M cadmium for Dunaliella salina, and 0.78 M copper and 0.025 M cadmium for Chlamydomonas bullosa. The relationship of the two cations was synergistic towards the growth of both species. Chronic exposure to 4.5×10^–6 M cadmium or 4.9×10^–4 M copper increased the sensitivity of C. bullosa by 26% and 29% towards cadmium and copper, respectively. Changes in co-tolerance were not observed. Cd-treated D. salina was 50% more tolerant towards this cation, whereas Cu-treated cultures showed extreme sensitivity towards copper and co-sensitivity towards cadmium. Furthermore, the phylogenetic hypothesis, predictive of toxic response, failed to hold at the familial level.This work was submitted by Ioanna Visviki to the Department of Biology of the Graduate School of the City University of New York in partial fulfillment of the requirements of the PhD degree.     

Monitoring lead pollution near a storage battery recycling plant in Taiwan, Republic of China

This study presents the distribution of blood lead levels and lead in various environmental samples (water, sediments, soils, and air) near the Shing-Yie storage battery recycling plant in Taiwan before (July 1990 to June 1991) and after (July 1992 to June 1993) amelioration. Before amelioration, the average blood lead levels in the neighborhood of the plant were in the range of 10.55±5.7 to 12.28±7.9 g/dl. After amelioration, relatively lower average concentrations of blood lead (range 8.35±3.0 to 9.13±2.5 g/dl) were generally found; however, these averages were still higher than that (7.79±3.5 g/dl) from other lead-unpolluted areas of Taiwan. An exceedingly high geometric mean (GM) lead concentration (128 g/L) was found in the downstream river water of the Tawulum River passing by the plant. The concentrations of lead (GM=372 and 418 g/g) in the downstream river sediments were higher than those (GM=123 and 158 g/g) in the upstream river sediments before and after amelioration, respectively. Furthermore, lead species in river sediments were analyzed by a sequential leaching technique. The sum of phases I, II, and III accounted for 83.7% of total lead at station R₂ (nearest to the plant). Maximum lead concentration (GM=2402 g/g) in dust at the soil surface from station S₁ (nearest to the plant) was much higher than those from the other stations by about 18 times before amelioration. However, the maximum value dropped to 1,155 g/g after amelioration. On the whole, the geometric mean concentration of lead in dust at the soil surface nearest to the plant was >1,000 g/g and decreased to <100 g/g in the 15–30 cm depth soil about 2 km away from the plant. Before amelioration, the geometric mean lead concentration of 4.57 g/m³ (range 0.102–37.6 g/m³) in the air near the plant was higher than that at the background locations, the geometric mean value of which was 0.08 g/m³.     

Toxicity of microencapsulated permethrin to selected nontarget aquatic invertebrates

Microencapsulated permethrin (penncapthrin) was evaluated under laboratory conditions for its toxicity toward several nontarget aquatic invertebrates. Average LC50 estimates for selected lotic invertebrates, based on a one hour dosing regime, were: 2.71 mg/L forSimulium vittatum, 4.59 mg/L forHydropsyche spp., and 13.41 mg/L forIsonychia bicolor. In acute static tests withDaphnia magna, there was no significant difference (p0.05) between the toxicity of penncapthrin at 96 h (LC50 range: 6.80–22.5 g/L) and the EC formulation at 72 h (LC50 range: 0.6–21 g/L). Comparatively, the toxicity of microencapsulated methyl parathion (penncap-m) was not significantly different from that of penncapthrin towardD. magna, the former having LC50 estimates ranging form 0.3–12.25 g/L. LC50 estimates associated withDaphnia pulex ranged from 19 to 131 g/L. The toxicity of penncapthrin and penncap-m towardD. pulex was difficult to determine because of frequent control mortality due to food deprivation resulting from the need to run tests for longer than 48 h. In successful tests, LC50 estimates ranged from 19 to 28 g/L for penncapthrin and 0.08 to 25 g/L for penncap-m after 72 h exposure. In long term toxicity tests, 95% of D. magna at 1 g/L, 44% at 10 g/L, and 20% at 15 g/L survived after 39 days exposure. Less than 15% ofD. pulex survived over the same concentration range following 32 days exposure. Despite some drawbacks, long-term toxicity tests were more appropriate than short-term tests for evaluating microencapsulated sticides because of reduced variability in LC50 estimates and lower control mortality.     

Pesticide and PCB residues in the upper Snake River ecosystem,Southeastern Idaho,following the collapse of the Teton Dam 1976

The Teton Dam in Southeastern Idaho collapsed on June 5, 1976. The resulting flood damaged a large area and caused the release of toxicants into the Snake River. A pesticide recovery team in a helicopter worked the flooded area for three weeks and collected 1,104 containers, about 35% of which contained toxicants. It was estimated that less than 60% of the lost pesticide containers were recovered.This paper addresses the results of a one-time sampling effort designed to determine the magnitude of the chemical contamination. Over 300 samples of fish, plankton, waterfowl, sediments, water, stream drift, aquatic plants, and soil were taken. Pesticide residues were measured asg/kg (ppb) wet weight, whole animal basis. Rainbow trout had as much as 1432g/kg total DDT plus analogs, 66g/kg dieldrin, and 1010g/kg PCBs. Utah suckers had up to 1420g/kg total DDT plus analogs, 32g/kg dieldrin, and 1800g/kg PCB. Rocky Mountain whitefish had as much as 2650g/kg total DDT and analogs, 30g/kg dieldrin and 1400g/kg PCBs. These PCB and DDT levels were high, approaching the 2,000g/kg FDA proposed tolerance, but were below the 5,000g/kg present tolerance. Dieldrin levels were low and organophosphates were undetectable.An undeveloped area (the Fort Hall Bottoms) showed higher levels of contaminants than did an industrialized area (the lower Portneuf River). This apparent discrepancy remains unexplained.Very little pre-flood data on a whole fish basis were available for comparison (Johnsonet al 1977). However, it does not appear that any human health hazard due to pesticide levels exists in this portion of the Snake River.     

Investigations on neurotoxicity of chemical substances at the workplace

Summary A cross-sectional study was performed in order to investigate the influence of chronic lead-exposure on the peripheral nervous system. We examined 148 male workers of a storage battery manufacturing plant, who had been exposed to lead metal and inorganic lead compounds for 1 to 28 years (mean 11 years). Fifteen workers with non-occupational risks of peripheral neuropathy (former diseases, alcohol abuse, medication) were excluded from the study. The investigation program comprised: case history, physical examination, analyses of blood- and urine-samples and determination of maximal motor, mixed and sensory conduction velocity (NCV) of the ulnar and median nerve of the right forearm. Objectively no worker showed any signs of health effects related to lead exposure. The Biological Monitoring included the determination of (1) Blood-lead level (Pb-B), (2) Free erythrocyte porphyrins (FEP), (3) -Aminolevulinic acid dehydratase (ALA-D) and (4) -Aminolevulinic acid in urine (ALA-U). Further time-weighted-average (TWA)-values of Pb-B were calculated on the basis of several determinations over the period 1975–1981. The following actual (TWA) median values resulted: Pb-B 53 g/dl (54 g/dl), ALA-U 5.6 mg/l (8.4 mg/l), FEP 2.0 mg/l (2.0 mg/l). The Biologischer Arbeitsstoff Toleranz Wert (BAT) of 70 g//dl for Pb-B was exceeded in 15 workers (11%), and of 15 mg/l for ALA-U in 30 cases (23%). In comparison with age-matched controls, the lead workers showed a mild slowing of NCV with mean values between 0.8 and 2.0 m/s. Multiple stepwise regression analyses revealed statistically significant correlations between the four NCV and age as well as Pb-B. There were better correlations by using TWA than actual data of Pb-B. Consideration of the results of the regression analyses, together with an evaluation of the individual neurophysiological status as a function of internal lead exposure, a dose-effect-relationship was found only in the case of Pb-B exceeding 70 g/dl. From our study it is concluded that chronic lead exposure resulting in blood-lead levels of below 70 g/dl is no occupational risk causing a functionally significant slowing of nerve conduction velocities.With Grants from the Deutsche Forschungsgemeinschaft, Bonn (Project no. Va 23/19-1)     

Antiestrogenic Effects of Motorcycle Exhaust Particulate in MCF-7 Human Breast Cancer Cells and Immature Female Rats

The emissions from 2- and 4-stroke motorcycles pollute the air of urban areas where motorcycle is a popular means of transportation. This study aimed to determine the endocrine-disrupting activity of motorcycle exhaust particulate (MEP) using MCF-7 human breast cancer cells and immature female Wistar rats treated with organic extracts of MEP. Treatments with 1, 10, and 50 g/ml MEP extract for 2 and 4 days produced dose-dependent inhibition of thymidine incorporation and cell growth, respectively, in untreated and 1 nM 17-estradiol (E₂)-treated cells. Treatments of MCF-7 cells with MEP extract replaced [³H]E₂ from the estrogen receptor in a time- and concentration-dependent manner. These antiestrogenic and receptor binding properties of MEP extract were blocked by cotreatment of the cells with 2 M -naphthoflavone, a cytochrome P450 inhibitor and aryl hydrocarbon receptor antagonist. E₂ metabolism and HPLC analysis showed that treatment of MCF-7 cells with 50 g/ml MEP extract for 24 h increased E₂ 2- and 4-hydroxylation in microsomes. The MEP-mediated increase in E₂ 2-hydroxylation was inhibited by the addition of 1 M -naphthoflavone to MCF-7 microsomes. Cotreatment of immature female rats with 10 g/kg E₂ and 10 mg/kg MEP extract intraperitoneally for 3 days decreased the E₂-induced uterine weights. MEP extract alone showed no effect on rat uterine weight. The endocrine-disrupting activity of MEP extract was further confirmed in parallel experiments using MCF-7 cells and immature female rats treated with benzo(a)pyrene, an MEP constituent compound. The present findings demonstrate that MEP extract is antiestrogenic in vitro and in vivo and cytochrome P450 induction is an underlying mechanism.     

Development of a Sublethal Test to Determine the Effects of Copper and Lead on Scleractinian Coral Larvae

A new sublethal toxicity test was developed in this study to measure the effect of copper and lead on the motility of coral larvae. Larval motility was significantly affected by copper and lead doses immediately after dosing. The copper EC₅₀ values for motility of Goniastrea aspera brain coral larvae (12 h, 21 g/L; 24 h, 16 g/L; 48 h, 22 g/L) were much lower than the copper LC₅₀ values for G. aspera larval survival (6 h, 260 g/L, and 24 h, 121 g/L, for 5-day-old larvae and 6 h, 248 g/L, and 24 h, 136.64 g/L, for 6-day-old larvae) during the early part of the experiments. However, at later times, the LC₅₀ values (48 h, 40 g/L, for 5-day-old larvae and 48- h, 87 g/L, for 6-day-old larvae) were similar to the EC₅₀ values for larval motility. The lead 72-h EC₅₀ value for G. aspera larval motility (2900 g/L) was much lower than the lead 72-h LC₅₀ value for larval survival (9890 g/L). The results show that larval motility can be a useful parameter to measure in order to determine the sublethal effects of trace metals on coral larvae.     

The effects of poly chlorinated biphenyls and methylmercury,singly and in combination on mink. II: Reproduction and kit development

Adult ranch-bred mink (Mustela vison) were fed diets containing either 0, 1.0 g/g polychlorinated biphenyls (PCB) (Aroclor^® 1254), 1.0 g/g methylmercury (MeHg), a combination of 1.0 g/g PCB plus 1.0 g/g MeHg, or 0.5 g/g PCB plus 0.5 g/g MeHg. Fertility of adult male mink, percentage of females whelped or number of kits born per female were not affected by the treatments. However, growth rate of kits nursed by mothers exposed to 1.0 g/g PCB was significantly reduced. There was a synergistic effect of PCB and MeHg which reduced kit survival in groups receiving both chemicals simultaneously. Kit survival to weaning in the control, 0.5 g/g PCB/MeHg, and 1.0 g/g PCB/MeHg groups was 72.0%, 62.7% and 35.8%, respectively. The results suggest that growth and survival of mink kits are adversely affected at dietary levels of PCB and MeHg currently present in some environments.