Behavioral Alterations Following Exposure to a Mixture of Lead and Atrazine During Early Development in the Zebrafish Model System

Lead (Pb) and atrazine (ATZ) are hazardous environmental toxicants that can exist as a mixture in potable water. Numerous single chemical studies on Pb and ATZ support adverse health outcomes, including neurotoxicity, but mixture studies are limited. Th e aim of this study is to test the hypothesis that Pb and ATZ mixtures result in a greater than additive toxicity, causing increased adverse health outcomes than single chemical exposures. Th e zebrafish model system was exposed to 3 or 30 ppb (µg/L) ATZ, 10 ppb (equivalent to 0.1 µg/dL) or 100 ppb Pb, along with mixtures of each beginning at 1 hour postfertilization (hpf) and continuing through 120 hpf. A visual motor response behavioral assay was then conducted using the Noldus DanioVision. The visual motor response assay tracks locomotor movement over five alternating periods of dark and light. Th e behavior data was analyzed by phase with a repeated measures ANOVA. Th e 10 ppb Pb mixture behavior data showed significant hypoactivity in the 10 ppb Pb, 30 ppb ATZ, 3 ppb ATZ/10 ppb Pb, and 30 ppb ATZ/10 ppb Pb treatments for all parameters in multiple phases (p \u3c 0.05). Th e 100 ppb Pb mixture behavior data also showed significant hypoactivity in the 100 ppb Pb and 30 ppb ATZ treatment groups, along with hypoactivity in both mixture treatment groups (p \u3c 0.05). Additionally, the 3 ppb ATZ treatment group had hyperactivity in the third dark phase (p \u3c 0.05). Th ese data align with past single chemical behavior studies and indicate a greater than additive mixture toxicity

Low Immune Response to Hepatitis B Vaccine among Children in Dakar, Senegal

HBV vaccine was introduced into the Expanded Programme on Immunization (EPI) in Senegal and Cameroon in 2005. We conducted a cross-sectional study in both countries to assess the HBV immune protection among children. All consecutive children under 4 years old, hospitalized for any reason between May 2009 and May 2010, with an immunisation card and a complete HBV vaccination, were tested for anti-HBs and anti-HBc. A total of 242 anti-HBc-negative children (128 in Cameroon and 114 in Senegal) were considered in the analysis. The prevalence of children with anti-HBs ≥10 IU/L was higher in Cameroon with 92% (95% CI: 87%–97%) compared to Senegal with 58% (95% CI: 49%–67%), (p<0.001). The response to vaccination in Senegal was lower in 2006–2007 (43%) than in 2008–2009 (65%), (p = 0.028). Our results, although not based on a representative sample of Senegalese or Cameroonian child populations, reveal a significant problem in vaccine response in Senegal. This response problem extends well beyond hepatitis B: the same children who have not developed an immune response to the HBV vaccine are also at risk for diphtheria, tetanus, pertussis (DTwP) and Haemophilus influenzae type b (Hib). Field biological monitoring should be carried out regularly in resource-poor countries to check quality of the vaccine administered

Brief Communication - Evaluation of commercially available third-generation anti-hepatitis C virus enzyme-linked immunosorbent assay in patients on haemodialysis

Restricted antibody reactivity to hepatitis C virus (HCV) synthetic peptides has been observed in HCV-infected patients on haemodialysis (HD). The aim of this study was to evaluate third-generation anti-HCV enzyme-linked immunosorbent assay (ELISA) test systems containing either synthetic peptide HCV antigens or recombinant HCV antigens or a combination of synthetic and recombinant antigens in screening of 69 chronic renal failure patients on HD for HCV infection. Seven patients were detected to have antibodies to HCV by the &apos;recombinant HCV antigens&apos;-containing kits, of which the recombinant immunoblot assay for HCV confirmed four cases. The recombinant kits had a sensitivity of 100% and a specificity of 66%. However, the ELISA kits with only synthetic HCV antigens failed to detect antibodies in any of the cases (zero sensitivity). Hence a recombinant protein containing ELISA test system is ideal for screening of HCV infection in patients on hemodialysis

Dicopper Cu(I)Cu(I) and Cu(I)Cu(II) Complexes in Copper-Catalyzed Azide-Alkyne Cycloaddition.

A discrete, dicopper μ-alkynyl complex, [Cu2(μ-η1:η1-C≡C(C6H4)CH3)DPFN]NTf2 (DPFN = 2,7-bis(fluoro-di(2-pyridyl)methyl)-1,8-naphthyridine; NTf2- = N(SO2CF3)2-), reacts with p-tolylazide to yield a dicopper complex with a symmetrically bridging 1,2,3-triazolide, [Cu2(μ-η1:η1-(1,4-bis(4-tolyl)-1,2,3-triazolide))DPFN]NTf2. This transformation exhibits bimolecular reaction kinetics and represents a key step in a proposed, bimetallic mechanism for copper-catalyzed azide-alkyne cycloaddition (CuAAC). The μ-alkynyl and μ-triazolide complexes undergo reversible redox events (by cyclic voltammetry), suggesting that a cycloaddition pathway involving mixed-valence dicopper species might also be possible. Synthesis and characterization of the mixed-valence μ-alkynyl dicopper complex, [Cu2(μ-η1:η1-C≡C(C6H4)CH3)DPFN](NTf2)2, revealed an electronic structure with an unexpected partially delocalized spin, as evidenced by electron paramagnetic resonance spectroscopy. Studies of the mixed-valence μ-alkynyl complex's reactivity suggest that a mixed-valence pathway is less likely than one involving intermediates with only copper(I)

Titanium Imido Complexes by Displacement of –SiMe3 and C–H Bond Activation in a TiIII Amido Complex, Promoted by a Cyclic (Alkyl)(Amino) Carbene (cAAC)

A strong σ-donating cyclic (alkyl)(amino) carbene (cAAC) triggers rearrangement of the silyl(aryl) amido ligand -N(SiMe3)Dipp (Dipp = 2,6-diisopropylphenyl) in the coordination sphere of titanium(III) to afford a novel zwitterionic titanium imido complex with a TiCH2SiMe2[cAAC] linkage. Reduction of this species produces a new DippN=Ti imido complex containing a cAAC-centered radical species, characterized by single crystal diffraction analysis and electron paramagnetic resonance spectroscopy

Titanium Imido Complexes by Displacement of –SiMe 3

A strong σ-donating cyclic (alkyl)(amino) carbene (cAAC) triggers rearrangement of the silyl(aryl) amido ligand -N(SiMe3)Dipp (Dipp = 2,6-diisopropylphenyl) in the coordination sphere of titanium(III) to afford a novel zwitterionic titanium imido complex with a TiCH2SiMe2[cAAC] linkage. Reduction of this species produces a new DippN=Ti imido complex containing a cAAC-centered radical species, characterized by single crystal diffraction analysis and electron paramagnetic resonance spectroscopy

Mixed Boron(III) and Phosphorous(V) Complexes of meso-Triaryl 25-Oxasmaragdyrins

Two unprecedented mixed B-III/P-V complexes of meso-triaryl 25-oxasmaragdyrins were synthesized in appreciable yields under mild reaction conditions. These unusual 25-oxasmaragdyrin complexes containing one or two seven-membered heterocyclic rings comprised of five different atoms (B, C, N, O, and P) were prepared by reacting B(OH)(Ph)-smaragdyrin and B(OH)(2)-smaragdyrin complexes, respectively, with POCl3 in toluene at reflux temperature. The products were characterized by HRMS and 1D- and 2D-NMR spectroscopy. X-ray crystallography of one of the mixed B-III/P-V smaragdyrin complexes indicated that the macrocycle is significantly distorted and contains a stable seven-membered heterocyclic ring within the macrocycle. The bands in the absorption and emission spectra were batho-chromically shifted with reduced quantum yields and singlet-state lifetimes relative to the free base, meso-triaryl 25-oxasmaragdyrin. The mixed B-III/P-V complexes were difficult to oxidize but easier to reduce than the free base. The DFT-optimized structure of the 25-oxasmaragdyrin complex with two seven-membered heterocycles indicated that it was a bicyclic spiro compound with two half-chair-like conformers. This was in contrast to the chair-like conformation of the complex with a single seven-membered heterocyclic ring. Moreover, incorporation of a second phosphate group in the former case stabilized the bonding geometry and resulted in higher stability, which was reflected in the bathochromic shift of the absorption spectra, more-positive oxidation potential, and less-negative reduction potential

A Stable Seven-Membered Heterocycle, Containing B, C, N, O, and P Atoms, inside a Smaragdyrin Macrocycle

Unprecedented examples of smaragdyrin macrocycles containing seven membered heterocyclic rings were synthesized under simple reaction conditions in high yields. The heterocycle formed inside smaragdyrin macrocycle is rare example of heterocycle containing five different atoms, such as B, C, N, O, and P atoms. The mixed B-III and P-V complexes of smaragdyrin macrocycles showed new structural, spectral, and electrochemical properties