Evaluation of a carbon paste electrode modified with organofunctionalised SBA-15 nanostructured silica in the simultaneous determination of divalent lead, copper and mercury ions

The performance of a carbon paste electrode (CPE) modified with SBA-15 nanostructured silica organofunctionalised with 2-benzothiazolethiol in the simultaneous determination of Pb(II), Cu(II) and Hg(II) ions in natural water and sugar cane spirit (cachaca) is described. Pb(II), Cu(II) and Hg(II) were pre-concentrated on the surface of the modified electrode by complexing with 2-benzothiazolethiol and reduced at a negative potential (-0.80 V). Then the reduced products were oxidised by DPASV procedure. The fact that three stripping peaks appeared on the voltammograms at the potentials of -0.48 V (Pb2+), -0.03 V (Cu2+) and +0.36 V (Hg2+) in relation to the SCE, demonstrates the possibility of simultaneous determination of Pb2+, Cu2+ and Hg2+. The best results were obtained under the following optimised conditions: 100 mV pulse amplitude, 3 min accumulation time, 25 mV s(-1) scan rate in phosphate solution pH 3.0. Using such parameters, calibration graphs were linear in the concentration ranges of 3.00-70.0 x 10(-7) mol L-1 (Pb2+), 8.00-100.0 X 10(-7) mol L-1 (Cu2+) and 2.00-10.0 x 10(-6) mol L-1 (Hg2+). Detection limits of 4.0 x 10(-8) mol L-1 (Pb2+), 2.0 x 10(-7) mol L-1 (Cu2+) and 4.0 x 10(-7) mol L-1 (Hg2+) were obtained at the signal noise ratio (SNR) of 3. The results indicate that this electrode is sensitive and effective for simultaneous determination of Pb2+, Cu2+ and Hg2+ in the analysed samples. (C) 2008 Published by Elsevier B.V.

Kvinnors upplevelser av fosterrörelser i slutet av graviditeten

Bakgrund: Det finns begränsad kunskap om hur kvinnor upplever fosterrörelser i slutet av graviditeten. Ökad kunskap om fosterrörelser kan bidra till bättre möjligheter att identifiera foster som riskerar att dö intrauterint. Syfte: Att utforska hur gravida kvinnor upplever fosterrörelser i slutet av en okomplicerad graviditet samt hur mammor som mist ett barn i livmodern upplevt kontakten med barnet tiden före beskedet att barnet hade dött. Metod: Delstudie I, djupintervjuer med 26 mammor vars barn dött före födelsen, efter 28 fullgångna graviditetsveckor. Delstudie II, frågeformulär till 393 kvinnor med okomplicerad graviditet som besvarades i graviditetsvecka 37 till 42. Svaren analyserades i båda studierna med kvalitativ innehållsanalys. Resultat: 22 mammor i delstudie I beskrev att de hade haft en föraning om att något kunde ha hänt deras barn innan de fick besked att barnet dött intrauterint. Föraningen grundades på att mammorna hade upplevt minskade eller uteblivna fosterrörelser. Det är något som inte stämmer; formulerades som ett sammanfattande tema på mammornas föraning. Processen mot insikten om att deras barn dött beskrivs i olika steg; Inte känna kontakt med barnet; Känna oro; Känna att något är fel; Inte begripa det ofattbara; Vilja få besked; Vara säker på att barnet har dött. I delstudie II beskrev 383 (96 %) kvinnor i fullgången okomplicerad graviditet olika rörelser som klassificerades som kraftfulla rörelser. De flesta kvinnorna beskrev flera typer av rörelser, tio (4 %) kvinnor beskrev fosterrörelser som inte inkluderade någon rörelse i kategorin kraftfulla rörelser. Konklusion: Mammor som mist sitt barn före födelsen hade känt en föraning om att deras väntade barn kunde må dåligt, de hade upplevt att de tappat kontakten med barnet innan de fick besked att barnet hade dött i livmodern men normaliserade känslan. De flesta kvinnor med okomplicerad, fullgången graviditet, beskriver att barnet rör sig med kraft och tryck, få kvinnor beskriver rörelser som inte kan kategoriseras som kraftfulla. Implikationer: Blivande mammor bör uppmanas att lita på sin upplevelse av att det är något som inte stämmer och kontakta sjukvården direkt om de är bekymrade över sitt ofödda barns rörelser. Bedömning av fosterrörelser i fullgången graviditet kan inkludera: förekomst, frekvens och intensitet. Nyckelord: Innehållsanalys, fosterdöd, fosterrörelser, fullgången graviditet, upplevelser

Att minska risken för våld och att främja återhämtning i den rättspsykiatriska vården : Patienters och personalens erfarenheter av vägen mot återhämtning

Detta avhandlingsarbete är utfört inom en rättspsykiatrisk vårdkontext och återspeglar patienters[1] och personals[2] erfarenheter och upplevelser av vändpunkter i samband med minskad risk för våld och återhämtning. Med utgångspunkt från ett holistiskt och salutogent hälsovetenskapligt perspektiv har avhandlingen ett tvärvetenskapligt förhållningssätt.   Teoretiska ämnesdiscipliner såsom psykiatrisk omvårdnad, kriminologi och sociologi har influerat arbetet. Avhandlingens övergripande syfte var att utifrån de salutogena aspekterna i det rättspsykiatriska omvårdnadsarbetet undersöka vad som är relaterat till vändpunkter i samband med minskad risk för våld och vad som bidrar till återhämtning. Avhandlingen baseras på fyra olika studier. Syftet med den inledande kvantitativa delstudien (I) var att identifiera och jämföra rättspsykiatriska patienter som sänkt sin bedömda risk för våld med 30 % eller mer enligt riskbedömningsinstrument HCR-20. Resultatet visade att den bedömda risken för våld minskade över tid. En demografisk analys genomfördes för att studera skillnader mellan de patienter som sänkt sin bedömda risk för våld och de som inte sänkt sin risk. Det framgick att rättspsykiatriska patienter som bedömts med hjälp av riskbedömningsinstrumentet HCR-20, minskade den bedömda risken för våld, både på kort och på lång sikt. Den rättspsykiatriska vården fungerade bäst när det gällde att förbättra de kliniska riskfaktorerna (C-skalan). Riskhanteringen (R-skalan) gällande eventuell utskrivning och framtida friförmåner visade inte samma goda progress. Demografiska karaktäristika såsom ålder, alkohol och drogmissbruk och psykiatriska diagnoser var inte relaterade till minskad risk för våld, dock var kvinnliga patienter och patienter utan psykopatidiagnos mer benägna att sänka sin risk för våld. Ett urval av de patienter som minskade sin risk för våld med 30 % eller mer utgjorde basen för delstudie II och III. I delstudie II intervjuades tretton rättspsykiatriska patienter om upplevelser och erfarenheter kring vad som bidrar till minskad respektive ökad risk för våld inne på en rättspsykiatrisk avdelning. Data analyserades med hjälp av en tolkande beskrivning (Interpretive Description). Studien visade att orsakerna till ökad respektive minskad risk för våld var processrelaterad, där interaktioner mellan personal och patienter bidrog till en utveckling som antingen präglades av välbefinnande eller disharmoni. Delstudie II utgjorde en viktig kunskapskälla som präglade ansatsen i delstudie III och IV. Detta med hänvisning till att flertalet patienter i delstudie II lämnade intressanta beskrivningar av vändpunkter i samband med minskad risk för våld och återhämtning. Sålunda intervjuades i delstudie III, tio rättspsykiatriska patienter om deras upplevelser av förändringsprocesser i samband med vändpunkter och återhämtning. Dataanalysen skedde med hjälp av en kvalitativ innehållsanalys. Processen beskrevs utifrån tre faser där man i högriskfasen upplevde kaotiska och överväldigande känslor. Vändpunkten upplevdes som ett känsligt skede som präglades av att tvingas hitta en ny, konstruktiv väg i livet. Återhämtningsfasen präglades av ett accepterande och en mognad. Stöd och erkännande från omgivningen ansåg främja dessa processer. Delstudie IV bestod av intervjuer med tretton personal. Syftet var att belysa upplevelser och erfarenheter kring rättspsykiatriska patienters vändpunkter och återhämtning. Kvalitativ innehållsanalys användes för att analysera data. Beskrivningar kring hur en vändpunkt kunde bevaras och främjas baserades på vikten av att vara uppmärksam, lyhörd och att inte skynda på processen. En vändpunkt upplevdes genom att patienten uppvisade synbara positiva förändringar. Sammansättningen på personalen och patienterna ansågs påverka atmosfären på avdelningen, och bidrog till huruvida processen mot vändpunkter och återhämtning underlättades eller försvårades. Avhandlingen visar hur ett ständigt växelspel mellan patienter och mellan personal bidrog till huruvida vårdatmosfären upplevdes såsom hälsofrämjande eller ej. Vidare framgår att processer kring vändpunkter i samband med minskad risk för våld och återhämtning präglades av känslor av sårbarhet och utsatthet. Processen beskrevs som ett känsligt förlopp som behövde understödjas av förtroendefulla relationer med andra, samt möjligheter att få vistas i en trygg miljö. [1] Den vetenskapliga litteraturen använder sig av begrepp såsom client, consumer, service user eller forensic patient för att beteckna människor som är inskrivna inom den rättspsykiatriska vården. Inom det psykiatriska svenska fältet kan begreppen brukare, vårdtagare eller patient förekomma. I denna avhandling kommer begreppet patient och vårdtagare omväxlande att användas för att beteckna de människor som är föremål för den rättspsykiatriska vården. De patienter som deltagit i avhandlingens två delstudier kommer omväxlande att benämnas såsom deltagare eller patienter, för att åstadkomma en varierande och läsvänlig text. [2] I denna avhandling anser begreppet personal den personalkategori som arbetar med omvårdnad inom en rättspsykiatrisk kontext. Det är främst sjuksköterskor och skötare som inkluderas i begreppet omvårdnadspersonal inom den vetenskapliga litteraturen. Sjuksköterskor benämns såsom registered mental health nurses eller registered nurses. Övrig omvårdnadspersonal tituleras till exempel som nurse manager eller assistant nurses. När begreppen personal, vårdare eller omvårdnadspersonal används i denna avhandling avses då den personalkategori som arbetar närmast patienten med omvårdnad och ingen åtskillnad kommer att göras mellan de båda yrkesgrupperna. Personalen som deltar i delstudie IV har omväxlande kallats för personal eller vårdare.

Estudo de fase I e farmacocinética com etoposide oral em crianças e adolescentes com tumores sólidos refratários

Introdução. Embora muitas crianças com câncer possam ser curadas, um número significativo têm resposta insatisfatória por ineficácia da terapêutica tornando necessário identificar agentes anticâncer mais efetivos contra tumores refratários ou recaídos. Estudos com Etoposide revelaram uma clara relação entre o tempo de exposição e os seus efeitos citotóxicos, mostrando resultados superiores com o uso de doses fracionadas quando comparado ao uso de uma dose única. Estudos de farmacocinética sugerem que as concentrações plasmáticas ativas de Etoposide se situa entre 1 e 5 μg/ml e que níveis acima de 5 μg/ml determinam uma mielotoxicidade importante. O Etoposide apresenta um bom espectro antitumoral mesmo em pacientes que já foram tratados por via parenteral e uma adequada biodisponibilidade pela via oral, podendo ser administrado com segurança em regime ambulatorial. Portanto, torna-se atraente a busca de esquemas de administração deste agente, os quais produzem níveis de concentração plasmática seguras pelo maior tempo possível. Objetivos. Os objetivos deste estudo de fase I é avaliar o perfil de toxicidade, a toxicidade dose-limitante, a dose máxima tolerada, a farmacocinética plasmática e a dose segura do Etoposide oral recomendada para estudos de fase II em pacientes pediátricos portadores de tumor sólido refratário. Materiais e Métodos. Todos os pacientes eram portadores de tumor sólido não responsivo aos tratamentos estabelecidos. A dose inicial do Etoposide foi de 20mg/m2/dose, a cada 8 horas durante 14 dias seguido de um intervalo de 7 dias antes de iniciar o próximo ciclo. A farmacocinética plasmática do Etoposide foi estudada durante o primeiro dia de tratamento e os níveis de Etoposide determinados pelo método de HPLC. Resultados. Dezessete pacientes foram incluídos no estudo, sendo que em 13 foram realizados o estudo de farmacocinética. O número total de cursos de quimioterapia foi de 64. Nove pacientes foram incluídos no Nível de dose I, sendo que leucopenia grau 2-3 foi observada em 5. A dose foi então escalonada para 25 mg/m2 (Nível de dose II) e fornecida a 8 pacientes subsequentes o que determinou leucopenia grau 3-4 em 4 deles. Este Nível de dose foi então considerado como DMT (Dose Máxima Tolerada). A TDL foi neutropenia. As concentrações plasmáticas máximas de Etoposide nos pacientes incluídos no Nível de dose I e II foram de 2,97 e 8,59 μg/ml, respectivamente, e os níveis da droga >1 μg/ml foi mantido durante cerca de 6,3 horas após a administração da droga em ambos os níveis de dose. Resposta parcial foi observada em 1 paciente e 4 apresentaram doença estável. Conclusões. A administração prolongada de Etoposide oral nas doses de 20 mg/m2 a cada 8 horas durante 14 dias consecutivos, seguidos de 7 dias de repouso, foi bem tolerada e determinou uma toxicidade manejável em crianças e adolescentes portadores de doenças malignas refratárias. A dose de 20 mg/m2 aparentemente preencheu os requisitos farmacocinéticos que objetivam melhorar o índice terapêutico do Etoposide, ou seja, a obtenção de níveis plasmáticos citotóxicos sustentados e abaixo do limite de toxicidade clínica da droga.

Híbridos à base de anilina/sílica obtidos através do processo sol-gel: síntese, caracterização e propriedades

Neste trabalho inicialmente foi sintetizado o precursor organoalcoxisilano 3- anilinapropiltrimetoxisilano, APTMS, a partir da reação entre a anilina e o 3- cloropropiltrimetoxisilano, CPTMS, usando hidreto de sódio, NaH, como ativador de base. O precursor inorgânico tetraetilortosilicato, TEOS, foi polimerizado na presença do precursor orgânico, e catalisador. Durante a etapa de polimerização dos precursores alcóxidos, foram investigadas as influências da temperatura, do tipo e concentração do catalisador e da concentração de precursor orgânico adicionado nas propriedades finais dos híbridos anilinapropilsilica resultantes. Os materiais híbridos foram caracterizados através das técnicas: espectroscopia no infravermelho (FT-IR), técnica de espalhamento de Raios-x a baixos ângulos (SAXS), microscopia eletrônica de varredura (SEM), isotermas de adsorção e dessorção de nitrogênio, análise elementar, espectroscopia de aniquilação de pósitrons (PALS), análise termogravimétrica (TGA), espectroscopia de elétrons dispersos (EDS). A potencialidade de aplicação dos híbridos obtidos como materiais adsorventes na extração dos cátions Cu(II), Zn(II), Cd(II) e Co(II), em solução, foi investigada usando-se isotermas de adsorção pelo método batelada. Através das técnicas de caracterização foi possível observar que as propriedades morfológicas dos materiais como área superficial, distribuição do tamanho de poros, forma e tamanho das partículas, além da estabilidade e grau de incorporação orgânica podem ser controladas em maior ou menor grau, dependendo da variável usada durante a polimerização dos precursores alcóxidos. O material apresentou propriedades promissoras como adsorvente seletivo para o cobre.

Development banks, risk and Basle II: some assessments

The implementation of the Basle II agreement in the financial markets of world economies has been seen as a significant advance in relation to the model enforced under the first agreement (Basle I). It is generally understood that the new agreement represents a substantial advance in relation to the first because it allows banks to better deal with the risks to which they are exposed. Nevertheless, when the application of these principles to development banks is considered it can be noted that certain inconsistencies exist, notably the fact that these institutions are typically public institutions - or at least strongly dependent on public funding - and they do not operate the payment system of the economy. Therefore, the application of the Basle rules to these institutions does not make sense. This means that Basle does not represent an appropriate set of recommendations for how these institutions should deal with their risks, whether because the proposed form of dealing with risks is inadequate, or because other relevant risks for these institutions are not covered by Basle I and II.

Coeficientes de difusão de metais em materiais não convencionais (agarose e acetato de celulose) usados na técnica de difusão em filmes finos por gradientes de concentração

The DGT technique allows one to measure quantitatively free and labile metal species in aquatic systems. Nevertheless, for this approach, knowledge is required of the diffusion coefficients of the analytes in a diffusive layer. In this study, the diffusion coefficients of Hg(II), As(III), Mn(II), Mg(II), Cu(II), Cd(II) were determined in agarose gel and those of Ba(II), Cd(II), Cu(II), Mg(II), Mn(II) e Zn(II) in cellulose acetate membranes. These materials presented good performance and the reported results can be used as a data base for further DGT studies.

Preparation, characterization, and CuX2 and CoX2 (X = Cl-, Br-, ClO4-) adsorption behavior of a polyhedral oligomer silsesquioxane functionalized with an organic base

In this paper we report on the synthesis, characterization, and adsorption properties of the first 3-amino-1,2,4-triazole-modified porous silsesquioxane (ATPS). The isotherms of adsorption of MX2 (M = Cu(II), Co(II); X = Cl-, Br-, ClO4-) by ATPS were studied in ethanol and aqueous solutions at 298 K. The results showed that there is a good fit between the experimental data and the Langmuir isotherm. The adsorption capacity in both solvents followed the sequence Cu(II) >> Co(II). The lowest adsorption for Co(II) should be related to the largest hydration volume, which obstructs the adsorption capacity of the surface, and consequently causes a decrease in the number of cations adsorbed. For the salts with different anions the sequence was MCl2 > MBr2 > M(ClO4)2 in both solvents. The low affinity for M(ClO4)(2) toward the solid phase is a consequence of the poorer coordination ability of the ClO4-. Adsorptions from ethanol solutions were higher than those from aqueous solutions due to the higher polarity of water, which can more strongly solvate the solute and the basic sites on the surface. The following adsorption capacities (in mmol g(-1)) were determined: 0.24 (aq) and 0.84 (eth) for CuCl2, 0.09 (aq) and 0.16 (eth) for CuBr2, and 0.08 (aq) and 0.11 (eth) for Cu(ClO4)(2); 0.02 (aq) and 0.07 (eth) for CoCl2, 0.02 (aq) and 0.06 (eth) for CoBr2, and 0.01 (aq) and 0.05 (eth) for Co(ClO4)(2). (c) 2007 Elsevier B.V. All rights reserved.

Approach combining on-line metal exchange and tangential-flow ultrafiltration for in-situ characterization of metal species in humic hydrocolloids

This paper deals with the development and optimization of an analytical procedure using ultrafiltration and a flow-injection system, and its application in in-situ experiments to characterize the lability and availability of metal species in humic-rich hydrocolloids. The on-line system consists of a tangential flow ultrafiltration device equipped with a 3-kDa filtration membrane. The concentration of free ions in the filtrate was determined by atomic-absorption spectrometry, assuming that metals not complexed by aquatic humic substances (AHS) were separated from the complexed species (M-AHS) retained by the membrane. For optimization, exchange experiments using Cu(II) solutions and AHS solutions doped with the metal ions Ni(II), Mn(II), Fe(III), Cd (II), and Zn(II) were carried out to characterize the stability of the metal-AHS complexes. The new procedure was then applied in-situ at a tributary of the Ribeira do Iguape river (Iguape, São Paulo State, Brazil) and evaluated using the ions Fe(III) and Mn(II), which are considered to be essential constituents of aquatic systems. From the exchange between metal-natural organic matter (M-NOM) and the Cu(II) ions it was concluded that Cu(II) concentrations > 485 mu g L(-1) were necessary to obtain maximum exchange of the complexes Mn-NOM and Fe-NOM, corresponding to 100% Mn and 8% Fe. Moreover, the new analytical procedure is simple and opens up new perspectives for understanding the complexation, transport, stability, and lability of metal species in humic-rich aquatic environments.

Study on soluble heavy metals with preconcentration by using a new modified oligosilsesquioxane sorbent

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Adsorption of transition-metal ions in ethanol solution by a nanomaterial based on modified silsesquioxane

The material octakis[3-(3-amino- 1,2,4-triazole)propyl]octasilsesquioxane (ATZ-SSQ) was synthesized and its potential was assessed for Cu(II), Ni(II), Co(II), Zn(II) and Fe(III) from their ethanol solutions and compared with related 3-amino-1,2,4-triazole-propyl modified silica gel (ATZ-SG). The adsorption was performed using a batchwise process and both organofunctionalized surfaces showed the ability to adsorb the metal ions from ethanol solution. The Langmuir model allowed to describe the sorption of the metal ions on ATZ-SSQ and ATTZ-SG in a satisfactory way. The equilibrium is reached very quickly Q min) for ATZ-SSQ, indicating that the adsorption sites are well exposed. The maximum metal ion uptake values for Cu(II), Co(II), Zn(II), Ni(II) and Fe(III) were 0.86, 0.09, 0.19, 0.09 and 0.10 mmol g(-1), respectively, for the ATZ-SSQ, which were higher than the corresponding values 0.21, 0.04, 0.14, 0.05 and 0.07 mmol g(-1) achieved with the ATZ-SG. In order to obtain more information on the metal-ligand interaction of the complexes on the surface of the ATZ-SSQ, Cu(II) was used as a probe to determine the arrangements of the ligands around the central metal ion by electron spin resonance (ESR). The ATZ-SSQ was used for the separation and determination (in flow using a column technique) of the metal ions present in commercial ethanol. (c) 2008 Elsevier B.V. All rights reserved.

Association between IGF-I, IGF-IR and GHRH gene polymorphisms and growth and carcass traits in beef cattle

Molecular biology techniques are of help in genetic improvement since they permit the identification, mapping and analysis of polymorphisms of genes encoding proteins that act on metabolic pathways involved in economically interesting traits. The somatotrophic axis, which essentially consists of growth hormone releasing hormone (GHRH), growth hormone (GH), insulin-like growth factors I and II (IGF-I and IGF-II), and their associated binding proteins and receptors (GHRHR, GHR, IGF-IR and IGF-IIR), plays a key role in the metabolism and physiology of mammalian growth. The objectives of the present study were to estimate the allele and genotype frequencies of the IGF-I/SnaBI, IGF-IR/TaqI and GHRH/HaeIII gene polymorphisms in different genetic groups of beef cattle and to determine associations between these polymorphisms and growth and carcass traits. For this purpose, genotyping was performed on 79 Nellore animals, 30 Canchim (5/8 Charolais+3/8 Zebu) animals and 275 crossbred cattle originating from the crosses of Simmental (n=30) and Angus (n=245) sires with Nellore females. In the association studies, traits of interest were analyzed using the GLM procedure of SAS and least square means of the genotypes were compared by the Tukey test. Associations of IGF-I/SnaBI genotypes with body weight and subcutaneous backfat were significant (p < 0.05), and nearly significant for longissimus dorsi area (p=0.06), with the 1313 genotype being favorable compared to the AB genotype. No significant associations were observed between this polymorphism and weight gain or carcass yield (P > 0.05). The IGF-IR/TaqI and GHRH/HaeIII polymorphisms showed no association with production traits. (c) 2004 Elsevier B.V All rights reserved.

Flame AAS determination of metal ions in fuel ethanol after preconcentration on acid carboxymethylcellulose (CMCH)

This paper describes the preparation of acid carboxymethylcellulose (CMCH), and the results of a study on the adsorption and preconcentration (using batch and flow-through column methods) of Cd(II), Cu(II), Cr(III), Fe(III), Ni(II) and Zn(II) in ethanol medium. The adsorption capacities for each metallic ion were (in mmol g(-1)) Cd(II) = 0.92; Cu(II) = 1.45; Cr(III) = 1.70; Fe(III) = 1.60; Ni(II) = 1.30; and Zn(II) = 1.10. By means of the flow-through method, a recovery of ca. 100% of the metallic ions adsorbed in a column packed with 2 g of CMCH was found when 5.0 mL of 1.0 mol L-1 hydrochloric acid were used as eluent. An enrichment factor of 20 (100 mt solution containing 50 mu g L-1 of the metallic ions, concentrated to 5.0 mt) was obtained by this preconcentration procedure. The sorption-desorption procedure applied allowed the development of a preconcentration and Flame AAS quantification method of metallic ions in fuel ethanol at trace levels.

Analysis of Bothrops jararacussu venomous gland transcriptome focusing on structural and functional aspects: I - gene expression profile of highly expressed phospholipases A(2)

Snake venom glands are a rich source of bioactive molecules such as peptides, proteins and enzymes that show important pharmacological activity leading to in local and systemic effects as pain, edema, bleeding and muscle necrosis. Most studies on pharmacologically active peptides and proteins from snake venoms have been concerned with isolation and structure elucidation through methods of classical biochemistry. As an attempt to examine the transcripts expressed in the venom gland of Bothrops jararacussu and to unveil the toxicological and pharmacological potential of its products at the molecular level, we generated 549 expressed sequence tags (ESTs) from a directional cDNA library. Sequences obtained from single-pass sequencing of randomly selected cDNA clones could be identified by similarities searches on existing databases, resulting in 197 sequences with significant similarity to phospholipase A(2) (PLA(2)), of which 83.2% were Lys49-PLA(2) homologs (BOJU-1), 0.1% were basic Asp49-PLA(2)s (BOJU-II) and 0.6% were acidic Asp49-PLA(2)s (BOJU-III). Adjoining this very abundant class of proteins we found 88 transcripts codifying for putative sequences of metalloproteases, which after clustering and assembling resulted in three full-length sequences: BOJUMET-I, BOJUMET-II and BOJUMET-III; as well as 25 transcripts related to C-type lectin like protein including a full-length cDNA of a putative galactose binding C-type lectin and a cluster of eight serine-proteases transcripts including a full-length cDNA of a putative serine protease. Among the full-length sequenced clones we identified a nerve growth factor (Bj-NGF) with 92% identity with a human NGF (NGHUBM) and an acidic phospholipase A2 (BthA-I-PLA(2)) displaying 85-93% identity with other snake venom toxins. Genetic distance among PLA(2)s from Bothrops species were evaluated by phylogenetic analysis. Furthermore, analysis of full-length putative Lys49-PLA(2) through molecular modeling showed conserved structural domains, allowing the characterization of those proteins as group II PLA(2)s. The constructed cDNA library provides molecular clones harboring sequences that can be used to probe directly the genetic material from gland venom of other snake species. Expression of complete cDNAs or their modified derivatives will be useful for elucidation of the structure-function relationships of these toxins and peptides of biotechnological interest. (C) 2004 Elsevier SAS. All rights reserved.

Determination of metal ions in natural waters by flame-AAS after preconcentration on a 5-amino-1,3,4-thiadiazole-2-thiol modified silica gel.

5-amino-1,3,4-thiadiazole-2-thiol groups attached on a silica gel surface have been used for adsorption of Cd(II), Co(II), Cu(II), Fe(III), Ni(II), Pb(II) and Zn(II) from aqueous solutions. The adsorption capacities for each metal ion were (in mmol.g(-1)): Cd(II)= 0.35, Co(II)= 0.10, Cu(II)= 0.15, Fe(III)= 0.20, Hg(Il)= 0.46, Ni(II)= 0.16, Pb(II)= 0.13 and Zn(II)= 0.15. The modified silica gel was applied in the preconcentration and quantification of trace level metal ions present in water samples (river, and bog water).