James E. Bollinger

Bioaccumulation of lead nitrate in red swamp crayfish (Procambarus clarkii)

Abstract Crayfish were exposed to intermediate concentrations of lead nitrate (150 μgl −1 and 1100 μgl −1 ) for periods up to 7 weeks. Lead clearance was monitored at 3 weeks following the 7 week exposure to the lower concentration. Lead bioaccumulation was demonstrated to be a time- and dose-dependent phenomenon in gills, hepatopancreas and abdominal muscle, but not the exoskeleton. The tissue concentrations of lead in soft tissues, in decreasing order were gills > hepatopancreas > muscle > hemolymph. Lead clearance was significant in all tissues evaluated except the hepatopancreas, the organ of metal storage and detoxification.

Bioaccumulation of chromium in red swamp crayfish (Procambarus clarkii)

Abstract Crayfish were exposed to a range of potassium dichromate concentrations (0.15, 0.30, 3.0 and 30 mg l−1) for periods up to 7 weeks. Chromium bioaccumulation in all tissues over the 7 week exposure period was not consistently time- and dose-dependent. The order of distribution of chromium into the various tissues was dependent upon the exposure concentration of the metal. Chromium clearance studies conducted 1 and 3 weeks following exposure demonstrated a concentration reduction in most tissues only at the highest exposure concentration of chromium (30 mg l−1). Histological studies demonstrated damage to both the gills and hepatopancreas at the lowest exposure concentration. The results suggest that the red swamp crayfish, Procambarus clarkii, is a useful biomarker for chromium exposure.

Lymphocyte proliferative response and tissue distribution of methylmercury sulfide and chloride in exposed rats

The immunotoxic effects and tissue distribution of different forms of methylmercury compounds were studied in rats. Methylmercury sulfide or methylmercury chloride was fed to rats at concentrations of 5 or 500 microg/L in drinking water for 8 wk. T-cell lymphocyte proliferative response to phytohemagglutinin (PHA) and determination of tissue distribution of mercury by gas chromatography using electron capture were assayed. Four different forms of mercury compounds were employed: MeHgS-, (MeHg)2S, (MeHg)3S+, and MeHgCl. Results indicated that exposure to methylmercury significantly enhanced lymphocyte responsiveness in most of the exposed groups at the low concentration of 5 microg/L, with the highest proliferative response (fourfold increase) in the MeHgCl group. At 500 microg/L, a significant decrease in the lymphocyte proliferative response was observed in the (MeHg)3S+ and MeHgCl groups; conversely, the MeHgS(-)- and (MeHg)2S-exposed animals had a modest increase of the lymphocyte proliferative response. The largest concentrations of all four mercury forms were detected in the kidney and spleen. The levels of mercury found in kidney, spleen, liver, brain, and testis were lower in the MeHgCl group than in those exposed to (MeHg)2S and (MeHg)3S+. These data indicate that the organ distribution of mercury and immune alteration may vary according to the chemical structure of the compound. This observation may have important implications in humans potentially exposed to low levels of methylmercury present in the environment, since the immune system plays an important regulatory role in the host-defense mechanisms.

Lipophilic hexadentate gallium, indium and iron complexes of new phenolate-derivatized cyclohexanetriamines as potential in vivo metal-transfer reagents

1,3,5-Tris(5-substituted salicylamino)cyclohexanes (H3L; R = H, NO2 or OMe) have been synthesized by Schiff-base condensation between cis-1,3,5-triaminocyclohexane and a substituted salicylaldehyde, followed by reduction with KBH4. Reaction of these compounds with gallium(III), indium(III) and iron(III) salts gave neutral six-co-ordinate N3O3 complexes of type [ML](M = Ga, In or Fe). The complexes have been characterized by a combination of infrared, 1H and 13C-{1H} NMR and mass spectroscopy. The distribution coefficients between octan-1-ol and water indicate that the complexes are lipophilic. The electronic absorption spectra of the high-spin iron(III) complexes show ligand-to-metal charge-transfer bands in the 450–500 nm range. The structures of five of the complexes have been confirmed by single-crystal X-ray crystallography.

Comparative analysis of nutrient data in the lower Mississippi River

Abstract As the second phase of a large-scale Tulane University Mississippi River water-quality database project, nutrient data on the lower Mississippi River have been examined for potential differences among sampling agencies, geographic locations and chemically similar nitrogen parameters. These data represent the most comprehensive source of information on nutrients in the Mississippi River available as a single database. Monthly means, grouped by parameter, sampling location and agency, were calculated and compared as paired sets, excluding months where data were not available for both sets. Evaluations using ANOVA indicated few differences among agencies providing nitrogen-compound data, although differences were observed in phosphorus-compound data from different sources. Unfiltered and filtered fractions of nitrate–nitrite were found to be comparable throughout the study area. Spatial examination of the nutrient data indicated few differences in inorganic nitrogen concentrations throughout the study area, but significant variability in total Kjeldahl nitrogen (TKN). Orthophosphate and total phosphorus concentrations increased through the study area from Arkansas [river miles (RM) 500–810] downstream to St. Francisville (RM 231–315), but with little or no change from Baton Rouge (RM 111–230) to the Gulf of Mexico. Results provide a combined data set from which preliminary calculations of daily nutrient loads in the Mississippi River between 1960 and 1997 were conducted.

Biodistribution of the lipophilic complexes 59Fe(RsalH2)3tach (R = H, NO2 and OMe) and 68Ga(NO2salH2)3tach

A series of highly lipophilic comploffs 59Fe(RsalH2)3tach (R = H, NO2, OMe) and 68Ga(NO2salH2)3tach have been evaluated in vivo as potentially clinically useful agents.

Iron-59 complexes of lipophilic hexadentate phenolate-derivatized cyclohexanetriamine ligands

Abstract The compounds (RsalH 2 ) 3 tachH 3 (R = H, NO 2 , OMe) have been synthesized by Schiff base condensation between cis -1,3,5-triaminocyclohexane and a substituted salicylaldehyde, followed by reduction with KBH4. Reaction of these compounds with iron(III) salts gives neutral hexacoordinate N 3 O 3 complexes of type Fe(RsalH 2 ) 3 tach. These complexes have been characterized by a combination of infrared, UV vis and mass spectroscopy. The distribution coefficients between 1-octanol and water indicate that the complexes are lipophilic. The electronic absorption spectra of the high spin Fe(III) complexes show LMCT bands in the 450–500 nm range. These lipophilic complexes in vivo do not cross the blood-brain barrier to any significant extent.

Protonation and stability constants for the complexation of K+, Rb+ and Cs+ with 5, 11, 17, 23, 29, 35-hexakis-tert-butyl-37, 39, 41-trimethoxy-38, 40, 42-tris-oxoacetic acid calix[6]arene

Abstract The stability constants for the K+, Rb+ and Cs+ complexes of 5, 11, 17, 23, 29, 35-hexakis-tert-butyl-37, 39, 41-trimethoxy-38, 40, 42-tris-oxoacetic acid calix[6]arene have been determined, and the species present over a range of solution pHs identified.