Seabird colonies as relevant sources of pollutants in Antarctic ecosystems: Part 2 - Persistent Organic Pollutants.

Despite typically not being taken into account (usually in favour of the 'global distillation' process), the input of persistent organic pollutants (POPs) through biological activities can be indeed relevant at the local scale in terrestrial polar environments when seabird colonies are considered. Seabirds can bioaccumulate and biomagnify POPs, gather in large numbers and excrete on land during their reproductive season, thus making them locally as relevant secondary sources of POPs. The first part of this study indicated that these colonies act as so for several essential and non-essential trace elements, and this second part tests the same hypothesis concerning POPs using the very same samples. Lichens (n = 55), mosses (n = 58) and soil (n = 37) were collected from 13 locations in the South Shetlands Archipelago during the austral summers of 2013-14 and 2014-15. They were divided in colony (within the colony itself for soil and within and surrounding the colony for vegetation) and control (at least 150 m away from any colony interference) and analysed for POPs such as organochlorine pesticides, polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers and stable isotopes (C and N). Results showed that colonies act clearly as a secondary source for PCBs and likely for hexachlorobenzene. As in the first part, probable local sources other than the colonies themselves are hypothesised because of high concentrations found in control sites. Again, soil seemed the most adequate matrix for the intended purposes especially because of some particularities in the absorption of animal-derived organic matter by vegetation, pointed out by stable isotope analyses.

Contrasting phylogeographic pattern among Eudyptes penguins around the Southern Ocean.

Since at least the middle-Miocene, the Antarctic Polar Front (APF) and the Subtropical Front (STF) appear to have been the main drivers of diversification of marine biota in the Southern Ocean. However, highly migratory marine birds and mammals challenge this paradigm and the importance of oceanographic barriers. Eudyptes penguins range from the Antarctic Peninsula to subantarctic islands and some of the southernmost subtropical islands. Because of recent diversification, the number of species remains uncertain. Here we analyze two mtDNA (HVRI, COI) and two nuclear (ODC, AK1) markers from 13 locations of five putative Eudyptes species: rockhopper (E. filholi, E. chrysocome, and E. moseleyi), macaroni (E. chrysolophus) and royal penguins (E. schlegeli). Our results show a strong phylogeographic structure among rockhopper penguins from South America, subantarctic and subtropical islands supporting the recognition of three separated species of rockhopper penguins. Although genetic divergence was neither observed among macaroni penguins from the Antarctic Peninsula and sub-Antarctic islands nor between macaroni and royal penguins, population genetic analyses revealed population genetic structure in both cases. We suggest that the APF and STF can act as barriers for these species. While the geographic distance between colonies might play a role, their impact/incidence on gene flow may vary between species and colonies.

Seabird colonies as relevant sources of pollutants in Antarctic ecosystems: Part 1 - Trace elements.

Global distillation is classically pointed as the biggest responsible for contaminant inputs in Polar ecosystems. Mercury (Hg) and other trace elements (TEs) also present natural sources, whereas the biologically mediated input is typically ignored. However, bioaccumulation and biomagnification combined with the fact that seabirds gather in large numbers into large colonies and excrete on land might represent an important local TEs input. A previous work suggested these colonies as sources of not only nutrients, but also organic contaminants. To evaluate a similar hypothesis for TEs, samples of lichen (n = 55), mosses (n = 58) and soil (n = 37) were collected in 13 locations within the South Shetlands Archipelago during the austral summers of 2013-14 and 2014-15. They were divided in: "colony" (within the colony itself for soil and bordering it for vegetation) and "control" (at least 50 m away from colony interference), analysed for TEs (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, and Zn) and stable isotopes (C and N). In most cases, soil seems the best matrix to assess colonies as TEs sources, as it presented more differences between control/colony sites than vegetation. Colonies are clearly local sources of organic matter, Cd, Hg and likely of As, Se and Zn. Conversely, Co, Cr, Ni and Pb come presumably from other sources, natural or anthropogenic. In general, isotopes were more useful for interpreting vegetation data due to fractionation of absorbed animal-derived organic matter. Other local Hg sources could be inferred from high levels in control sites, location and wind patterns.

Trace elements concentrations in Buff-breasted Sandpiper sampled in Lagoa do Peixe National Park, Southern Brazil.

Cadmium, cobalt, chromium, copper, manganese, nickel, zinc and lead concentrations were detected in feathers of Buff-breasted Sandpipers (Calidris subruficollis) captured during the non-breeding season and analyzed with relationship to body mass. Of these metals tested for, only copper levels (2.28 µg/g) were positively correlated with bird body mass. Zinc levels showed higher concentration (67.97 µg/g) than the other metals, and cadmium levels showed the lowest concentration (0.14 µg/g). Trace element concentrations were below toxicity levels for all tested chemicals and we suggest that this probably reflects that essential elements are maintained there by normal homeostatic mechanism and that no excessive environmental exposure to these elements during migration or on the wintering area is suggested by these results.

Trace elements concentrations in Buff-breasted Sandpiper sampled in Lagoa do Peixe National Park, Southern Brazil / Concentração de elementos-traço em maçarico-acanelado amostrados no Parque Nacional da Lagoa do Peixe, Sul do Brasil

Abstract Cadmium, cobalt, chromium, copper, manganese, nickel, zinc and lead concentrations were detected in feathers of Buff-breasted Sandpipers (Calidris subruficollis) captured during the non-breeding season and analyzed with relationship to body mass. Of these metals tested for, only copper levels (2.28 µg/g) were positively correlated with bird body mass. Zinc levels showed higher concentration (67.97 µg/g) than the other metals, and cadmium levels showed the lowest concentration (0.14 µg/g). Trace element concentrations were below toxicity levels for all tested chemicals and we suggest that this probably reflects that essential elements are maintained there by normal homeostatic mechanism and that no excessive environmental exposure to these elements during migration or on the wintering area is suggested by these results.

Resumo As concentrações de cádmio, cobalto, cromo, cobre, manganês, níquel, zinco e chumbo foram detectadas em penas de Maçarico-acanelado (Calidris subruficollis) capturados durante o período de invernada e analisados em relação a massa corporal. Destes metais analisados, somente os níveis de cobre (2,28 µg/g) foram correlacionados positivamente com a massa corporal dos indivíduos. Níveis de zinco apresentaram-se mais altos (67,97 µg/g) que outros metais e os níveis de cádmio apresentaram as menores concentrações (0,14 µg/g). As concentrações dos elementos-traços estão abaixo dos níveis de toxicidade em todos os testes químicos e sugerimos que isto provavelmente ocorre pela manutenção dos elementos essenciais através do mecanismo normal de homeostase e não reflete a exposição destes elementos durante a migração ou nas áreas de invernada.

Homologous onset of double layer convection.

The onset of convection in two superimposed fluid layers of the same height is considered. It is found that the neutral curve for R(a) for the onset Rayleigh number R in dependence on the wave number a is an invariant of a multidimensional parameter space of property ratios of the system even though the corresponding convection solutions may vary strongly with these property ratios. For each neutral curve R(a) two manifolds of solutions are found one of which can be understood on the basis of symmetry properties of the system, while the other does not exhibit simple symmetry features. In particular the neutral curves R(a) for various single Rayleigh-Bénard convection layers are shown to correspond to two two-dimensional manifolds of solutions. Analytical expressions for the latter are derived in the case of outer stress-free boundary conditions.

Immunoglobulin G-positive in B-cell cross-match decreases kidney allograft survival.

We retrospectively studied all 1149 transplants performed at our center between 1993 and 2003 to determine the incidence and clinical effect of pretransplant B-positive cross-match on kidney graft survival. The patients were divided in two groups: B-negative (n = 1102) and B-positive in current sera (n = 47; 4.1%). AB-positive test was more frequent among regrafted patients (14% vs 3%; P = .00). Demographic data were not different between the groups. The overall rate of graft loss was similar (26% vs 24%, respectively; P = .86). However, early nonsurgical graft losses were more frequent among B-positive patients (46% vs 20%, respectively; P = .04). IgM was the most frequent immunoglobulin in the B-positive group (76% IgM and 24% IgG). There was no significant difference between B-negative and B-positive groups in the 1-, 5-, and 10-year graft survival rates (87% vs 83%, 73% vs 78%, 64% vs 66%, respectively; P = .87). The graft survival was significantly reduced comparing an IgG anti-B cell to the B-negative group (P = .03) as well as IgG compared to IgM (P = .004). In conclusion, only B-positive cross-match due to IgG decreased graft survival. Even though it is an uncommon situation (0.9%), this study stressed the clinical value of the B-cell cross-match as a tool to identify patients with a higher immunological risk.

Mucopolysaccharidosis type VI: Identification of novel mutations on the arylsulphatase B gene in South American patients.

Mucopolysaccharidosis type VI (Maroteaux-Lamy syndrome, MPS VI) is an autosomal recessive disorder caused by deficiency of N-acetylgalactosamine-4-sulphatase (ARSB),which leads to the lysosomal accumulation and excretion of dermatan sulphate (DS). In this study, 13 unrelated MPS VI patients (12 Brazilian and 1 Chilean) were investigated regarding the identification of the ARSB gene mutations using PCR, SSCP and sequencing. The exons with altered mobility on SSCP were sequenced, as well as all the exons of patients with no SSCP alteration. Seven novel mutations were identified: D59N, L72R, Q88H, P93S, R197X, 1279delA and c.1143-8T > G. The previously reported mutations 1533del23, R315Q and 427delG were found in six, three and two alleles respectively. The other mutations already reported, S384N and G144R, were found in only one allele. In addition, three polymorphisms previously described (V358M, V376M and P397P) were detected in the patients analysed. Our findings are in agreement with the literature confirming the great genetic heterogeneity associated with MPS VI.

Comparison between RFLP-PCR and antigenemia for pp65 antigen for diagnosis of cytomegalovirus disease after kidney transplantation.

Cytomegalovirus (CMV) infection is the single most frequent infectious complication in renal transplant recipients. The purpose of this study was to analyze the diagnostic efficacy of PCR-RFLP compared to antigenemia for CMV disease (CMVD) in kidney transplant recipients. From November 2001 to February 2002, 19 renal adult transplant recipients were followed with weekly measurements of CMV pp65 antigen to monitor the activity of CMV from the week 4 to 12 posttransplantation. Only 4 (21.1%) patients did not develop viremia during the first 12 posttransplantation weeks. Active infection was observed in 15 patients (78.9%): asymptomatic viremia in 6 (31.6%) and CMVD in 9 (47%). All patients who developed CMVD showed positivity in both methods during the observation period. The number of positive cells ranged from 11 to 292 cells in patients with CMVD and one to eight cells among those with asymptomatic viremia. Both methods revealed 100% sensitivity for CMVD diagnosis. The specificity was 60% for antigenemia and 70% for PCR, with positive predictive values of 60% and 75%, respectively.

Theoretical study of flow coupling mechanisms in two-layer Rayleigh-Bénard convection.

Rayleigh-Bénard convection in a system of two superimposed immiscible fluids, heated from below, is investigated theoretically. In a two-layer system, stationary convection is characterized by two distinct modes of flow coupling, namely, thermal coupling and viscous coupling. We derive two coupled amplitude equations in order to describe the nonlinear interaction of the viscous and the thermal coupling modes, whereby we restrict our analysis to the two-dimensional case. By analyzing the amplitude equations for varying fluid parameters, we make predictions concerning the stability of the involved coupling modes in the weakly nonlinear regime.

Marine debris and human impacts on sea turtles in southern Brazil.

Dead stranded sea turtles were recovered and examined to determine the impact of anthropogenic debris and fishery activities on sea turtles on the coast of Rio Grande do Sul State, Brazil. Esophagus/stomach contents of 38 juvenile green Chelonia mydas, 10 adults and sub-adults loggerhead Caretta caretta, and two leatherback Dermochelys coriacea turtles (adult or sub-adult) included plastic bags as the main debris ingested, predominated by white and colorless pieces. The ingestion of anthropogenic debris accounted for the death of 13.2% of the green turtles examined. Signs of damage over the body and carapace indicated that fishing activities caused the death of 13.6% (3/22) of loggerheads and 1.5% (1/56) of green turtles. Therefore, it appears that direct and indirect effects of fishing activities may pose a threat to these species in Brazilian waters. Other sources of plastic debris should be investigated as well as the direct impact of fisheries, especially bottom trawl and gill nets, in order to establish effective conservation action.

Usefulness of statistic experimental designs in enzymology: example with recombinant hCYP3A4 and 1A2.

First, the effects of 10 incubation factors were screened altogether on nifedipine dehydrogenase (NIF) and methoxyresorufin O-deethylase (MROD) activities catalyzed by recombinant human CYP3A4 and 1A2, respectively. Using a statistic experimental design, only 36 assays were needed to be exhaustive. Eight factors influenced CYP3A4-mediated NIF activity: buffer type, pH, temperature, Mg/EDTA, cytochrome b5, NADPH-P450 reductase, NADH, and solvent. Two factors had no significant effect: total ionic concentration and catalase/reduced glutathione. Six factors influenced CYP1A2-mediated MROD rates: buffer type, pH, temperature, Mg/EDTA, NADH, and glycerol. Four factors had no significant effect: total ionic concentration, cytochrome b5, reductase, and NAD+. Secondly, the combined effects of ionic strength and Mg concentration on NIF/CYP3A4 were studied and easily modeled using another statistic experimental design. The effect of Mg was strong at a constant ionic strength of 100 mM and negligible at a constant ionic strength of 500 mM. Thirdly, the effects of influencing factors and their interactions on MROD/CYP1A2 were modeled after 40 assays using a third statistic experimental design. Later experiments confirmed the predictivity of the models and the efficiency of optimized conditions. This approach can be applied to other biochemistry areas.

Involvement of human CYP1A isoenzymes in the metabolism and drug interactions of riluzole in vitro.

Cytochrome P450 (CYP) and uridine diphosphate glucuronosyltransferase (UGT) isoenzymes involved in riluzole oxidation and glucuronidation were characterized in (1) kinetic studies with human hepatic microsomes and isoenzyme-selective probes and (2) metabolic studies with genetically expressed human CYP isoenzymes from transfected B-lymphoblastoid and yeast cells. In vitro incubation of [14C]riluzole (15 microM) with human hepatic microsomes and NADPH or UDPGA cofactors resulted in formation of N-hydroxyriluzole (K(m) = 30 microM) or an unidentified glucuroconjugate (K(m) = 118 microM). Human microsomal riluzole N-hydroxylation was most strongly inhibited by the CYP1A2 inhibitor alpha-naphthoflavone (IC50 = 0.42 microM). Human CYP1A2-expressing yeast microsomes generated N-hydroxyriluzole, whereas human CYP1A1-expressing yeast microsomes generated N-hydroxyriluzole, two additional hydroxylated derivatives and an O-dealkylated derivative. CYP1A2 was the only genetically expressed human P450 isoenzyme in B-lymphoblastoid microsomes to metabolize riluzole. Riluzole glucuronidation was inhibited most potently by propofol, a substrate for the human hepatic UGT HP4 (UGT1.8/9) isoenzyme. In vitro, human hepatic microsomal hydroxylation of riluzole (15 microM) was weakly inhibited by amitriptyline, diclofenac, diazepam, nicergoline, clomipramine, imipramine, quinine and enoxacin (IC50 approximately 200-500 microM) and cimetidine (IC50 = 940 microM). Riluzole (1 and 10 microM) produced a weak, concentration-dependent inhibition of CYP1A2 activity and showed competitive inhibition of methoxyresorufin O-demethylase. Thus, riluzole is predominantly metabolized by CYP1A2 in human hepatic microsomes to N-hydroxyriluzole; extrahepatic CYP1A1 can also be responsible for the formation of several other metabolites. Direct glucuronidation is a relatively minor metabolic route. In vivo, riluzole is unlikely to exhibit significant pharmacokinetic drug interaction with coadministered drugs that undergo phase I metabolism.

Selective attention and aphasia in adults: preliminary findings.

Thirteen patients with left-hemisphere stroke and history of aphasia and 13 normal controls were administered the covert orientation of visual attention task (COVAT). This task presents targets to the right or left of a central fixation point after a cue (84% of trials) or with no cue (16% of trials). Left-hemisphere damaged patients also received tests of language function at the time of the study. For targets presented 100 msec after cue onset, normal controls demonstrated equivalent responding for targets to the left and to the right of a central fixation point. Patients with left-hemisphere damage showed slower reaction times when responding to targets on the right as opposed to the left side of space when attention was first cued to the opposite side of space (invalid trials) or when attention was focused on a central fixation point (uncued trials), but they did not show slower reaction times on the right side when attention was first cued to the right (valid trials). For left-sided targets, no differences between valid, invalid, and uncued trials existed. Slower responding to right- as opposed to left-sided targets on invalid and uncued trials was correlated with impaired performance on six of seven language measures for patients with left-hemisphere damage. Implications for the relationship between language and selective attention systems in the left hemisphere are discussed.

6,9-Bis[(aminoalkyl)amino]benzo[g]isoquinoline-5,10-diones. A novel class of chromophore-modified antitumor anthracene-9,10-diones: synthesis and antitumor evaluations.

Synthetic procedures have been developed which lead to the 2-aza congeners 3 and several related N-oxides 4. The analogues 3 exhibited a wide range of in vitro cytotoxicity against L1210 leukemia, the human colon adenocarcinoma cell line LoVo, and the doxorubicin resistant LoVo/DX cell line. Selected analogues of 3 showed significant P388 antileukemic activity in mice with 3c exhibiting high activity. This activity was also retained in the related N-oxide 4a. These heterocyclic bioisosteric models are representative of the first anthracene-9,10-diones which display antileukemic activity comparable to mitoxantrone.

Remembering pictures: pleasure and arousal in memory.

Incidental memory performance for pictures that varied along the affective dimensions of pleasantness and arousal was assessed. For both an immediate and delayed (1 year later) free-recall task, only the arousal dimension had a stable effect on memory performance: Pictures rated as highly arousing were remembered better than low-arousal stimuli. This effect was corroborated in a speeded recognition test, in which high-arousal materials encoded earlier in the experiment produced faster reaction times than their low-arousal counterparts. Pleasantness affected reaction time decisions only for pictures not encoded earlier. These results suggest that whereas both the dimensions of pleasantness and arousal are processed at initial encoding, long-term memory performance is mainly affected by arousal.

Heterosubstituted anthracene-9,10-dione analogues. The synthesis and antitumor evaluation of 5,8-bis[(aminoalkyl)amino]naphtho[2,3-b] thiophene-4,9-diones.

A number of 5,8-bis[(aminoalkyl)amino]naphtho[2,3-b]thiophene-4, 9-diones have been synthesized and evaluated for antitumor activity against L1210 leukemia both in vitro and in vivo. Two of the congeners exhibited in vivo activities quite comparable to that of mitoxantrone.

Multiple-regression hospitalization-cost model for pharmacy cost analysis.

A multiple-regression model that used hospital data for a single diagnosis-related group (DRG) was developed and tested as a tool for measuring the effect of pharmaceutical services on costs. Computer-generated data from one university teaching hospital for fiscal year 1983 were used to develop a model for identifying patient-specific and treatment-specific factors that correlated with total hospital costs and adjusted total costs (total costs minus room and board). Costs were analyzed for patients hospitalized for cardiothoracic procedures (DRG 108). Data for 100 patients were included. The demographic, severity, treatment-intensity, and drug-use factors included in the model accounted for 95.6% of the variation in adjusted total cost. Length of stay, number of secondary surgical procedures, quantity of supplies or drugs used in the operating room, and several drug therapies--tobramycin, i.v. electrolytes, and i.v. fluids--had significant effects on adjusted total cost. This regression model was useful for assessing the effects of the choice of drug therapy or specific services on the costs for one DRG; it should be tested for other DRGs in other institutions. The usefulness of the model for planning cost-effective services is limited by the need for better billing information, cost-estimation techniques, and records of clinical services provided.