Urinary 2,5-hexanedione in workers exposed to n-hexane: influence of the sample treatment

The aim of the present study was to determine 2,5-hexanedione (2,5-HD), a metabolite of n-hexane, by gas chromatography/flame ionization detection in 31 workers exposed to n-hexane after two types of sample pretreatment, i.e., with (total 2,5-HD) and without (free 2,5-HD) acid hydrolysis. The mean urinary 2,5-HD was 0.52 mg/L (free) and 2.88 mg/L (total), this difference being significant (Student t-test, p < 0.05). The differences in the results according to the sample treatment support the need to modify the current Brazilian legislation, which proposes the analysis of 2,5-HD without indicating whether it is the free or total metabolite.

Determinação de 2,5-hexanodiona em urina empregando cromatografia líquida de alta eficiência, após derivatização com 2,4-dinitrofenil-hidrazina

A method for quantifying urinary 2,5-hexanedione was optimized and validated. Urine samples were hydrolyzed and derivatized with 2,4-dinitrophenylhydrazine. The analyte was separated in a high performance liquid chromatography system with a diode array detector, using a C18 column (150 x 4.6 mm, p.d. 5 µm) and a mobile phase composed of phosphate buffer pH 2.3:acetonitrile (40:60, v/v), at a flow rate of 1 mL/min. The chromatograms were monitored at 334 nm. Retention time was 7.3 minutes. Main validation parameters were: coefficient of determination: 0.9994, accuracy: 96 to 107%; intra-assay precision (RSD): 3.08 to 6.72%; inter-assay precision (RSD): 2.54 to 8.17% and limit of quantitation of 0.19 µg/mL.

Determinação da 2,5-hexanodiona em amostras de urina submetidas à hidrólise ácida: importância da coluna cromatográfica e do pH do meio

Acidic hydrolysis of samples is frequent in urinary 2,5-hexanodione determination. This hydrolysis should be performed under proper conditions, in order to avoid interference, such as the presence of 2,5-dimethylfurane and 2-acetylfurane. The results of the present work, as well as data from the literature, show that the use of non-polar or slightly polar chromatographic columns of 30 m length is an essential condition for 2,5-HD determination in an acid hydrolysed urine sample. In the same way the pH should be kept between 0.3 and 0.5. The mean concentrations of 2,5-HD in samples submitted to hydrolysis (0.50 ± 0.28 mg/g of creatinine) was about 3 times higher than those found in the samples without acid hydrolysis (0.19 ± 0.3 mg/g of creatinine).

Equilibrium studies of 2,2'-(5-bromo-6-methylpyrimidine-2,4-diyl)bis(azanediyl)dipropanoic acid with some transition-metal ions in aqueous solution

The stability constants of the 1:1 complexes formed between M2+ (M2+: Mn2+, Ni2+, Cu2+, or Cd2+) and BMADA2- (BMADA: 2,2'-(5-bromo-6-methylpyrimidine-2,4 diyl)bis(azanediyl)dipropanoic acid) were determined by potentiometric pH titration in aqueous solution (I = 0.1 mol L-1, NaNO3, 25 °C). The stability of the binary M - BMADA complexes is determined by the basicity of the carboxyl or amino groups. All the stability constants reported in this work exhibit the usual trend, and the order obtained was Mn2+< Ni2+ < Cu2+ > Cd2+. The observed stability order for BMADA approximately follows the Irving - Williams sequence. In the M - BMADA complexes, the M ion is able to form a macrochelate via the pyrimidine group of BMADA.

2-(4-IODO-2,5-DIMETOXIFENIL)-N-[(2-METOXIFENIL)METIL]ETAMINA OU 25I-NBOME: CARACTERIZAÇÃO QUÍMICA DE UMA DESIGNER DRUG

Drug trafficking and the introduction of new drugs onto the illicit market are one of the main challenges of the forensic community. In this study, the chemical profile of a new designer drug, 2-(4-iodine-2,5-dimethoxyphenyl)-n-[(2-methoxyphenyl)methyl]etamine or 25I-NBOMe was explored using thin layer chromatography (TLC), ultraviolet-visible spectrophotometry (UV-Vis), attenuated total reflection with Fourier transform infrared spectroscopy(ATR-FTIR), gas chromatography mass spectrometry (GC-MS) and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR MS). First, the TLC technique was effective for identifying spots related to 25C-, 25B- and 25I-NBOMe compounds, all with the same retention factor, Rf ≈ 0.50. No spot was detected for 2,5-dimethoxy-4-bromoamphetamine, 2,5-Dimethoxy-4-chloroamphetamine or lysergic acid diethylamide compounds. ATR-FTIR preserved the physical-chemical properties of the material, whereas GC-MS and ESI-MS showed better analytical selectivity. ESI(+)FT-ICR MS was used to identify the exact mass (m/z428.1706 for the [M + H]+ ion), molecular formula (M = C18H22INO3), degree of unsaturation (DBE = 8) and the chemical structure (from collision induced dissociation, CID, experiments) of the 25I-NBOMe compound. Furthermore, the ATR-FTIR and CID results suggested the presence of isomers, where a second structure is proposed as an isomer of the 25I-NBOMe molecule.

Spectrophotometric determination of arsenic in soil samples using 2-(5-bromo-2-pyridylazo)-5-di-ethylaminophenol (Br-PADAP)

In this paper, a new, simple and sensitive method for arsenic determination in soil is proposed. This is based on the reduction of silver (I) and iron (III) ions by arsine followed by a complexation reaction of iron (II) with the spectrophotometric reagent Br-PADAP 2-(5-bromo-2-pyridylazo)-5-di-ethylaminophenol. Arsenic determination with a Sandell's sensitivity of 3.1 10-4 cm-2, linear range from 0.1 µg ml-1 to 2.0 µg ml-1 (r560 = 0.9995), molar absorptivity of 2.45 10(5) l mol-1 cm-1 and a concentration detection limit of 1.4 ng ml-1 (3s) were obtained using a 10 ml sample volume. Selectivity was increased with the use of EDTA as a masking agent. The proposed method was applied for arsenic determination in the presence of several ions amounts in digested soil samples. The results revealed that antimony (III), mercury (II), germanium (IV), platinum (IV) interferes at all analyzed proportions. The interferences can be easily removed by the use of EDTA. Precision and accuracy obtained were satisfactory with a R.S.D. < 5 %. Recovery of arsenic in soil samples varied from 95.55 to 102.70 % with a mean of 99.63 %. These results demonstrated that the proposed method is applicable for arsenic analysis in different soil samples.

Alteração do teor de cálcio no banho de DP para 2,5 mEq/L é eficaz no reestabelecimento dos valores preconizados por diretrizes atuais em pacientes com PTH < 150 pg/dL

INTRODUÇÃO/OBJETIVO: A doença óssea adinâmica (DOA) é um achado comum em diálise peritoneal (PD) e é considerada fator de risco para desenvolvimento de fraturas e doença cardiovascular. Dados do BRAZPD apontam as soluções de cálcio a 3,5 mEq/L presentes na maioria das prescrições no país, que possui quase 9.000 pacientes em PD. É comum o balanço positivo de cálcio com concentrações a 3,5 mEq/L contribuindo para o desenvolvimento de DOA. Diretrizes atuais recomendam um PTHi na DRC V em diálise entre 2 e 9 vezes (150-500 pg/mL) o valor máximo da normalidade. O objetivo deste estudo foi avaliar a resposta em 6 meses do PTH-i após a conversão para solução de cálcio a 2,5 mEq/L de pacientes que usavam soluções com cálcio a 3,5 mEq/L e com PTH-i basal < 150 pg/mL. MÉTODOS: Coorte prospectiva, observacional, na qual todos pacientes prevalentes em PD entre janeiro de 2008 e janeiro de 2009 de um único centro foram incluídos. Critérios de inclusão foram:(1) estar em uso de solução de DP com cálcio a 3,5 mEq/L; (2)PTH sérico < 150 pg/mL. A critério médico, os pacientes poderiam ser convertidos ou não para soluções cálcio a 2,5 mEq/L. RESULTADOS: 35 pacientes (idade média 62 ± 17 anos) foram incluídos. Desses, 22 foram convertidos para solução de cálcio 2,5 mEq/L. Nefropatia diabética foi a principal doença de base (36%) seguido por HAS (25%) e GNC (14%). Os grupos apresentavam valores basais semelhantes de PTH, cálcio, fósforo e fosfatase alcalina. No grupo-intervenção, houve aumento significativamente maior de PTH em 6 meses comparado com o grupo-controle (Δ194 pg/dL versus Δ 92/dL; p < 0,05). Dos convertidos, 41% atingiram os valores alvo de PTH contra 14% (p < 0,05) do grupo-controle. Fósforo, cálcio e fosfatase alcalina foram semelhantes entre os grupos. CONCLUSÃO: O uso de soluções com cálcio a 2,5 mEq/L para pacientes com PTHi < 150 pg/dL comparado a soluções de cálcio 3,5 mEq/L parece uma estratégia simples e efetiva para trazer os valores de PTHi dentro da faixa atualmente sugerida nas diretrizes.

In Vitro and in Vivo Assays of 3,5-Disubstituted-Tetrahydro-2H-1,3,5-Thiadiazin-2-Thione Derivatives against Trypanosoma cruzi

Cytotoxicity assays of 24 new 3,5-disubstituted-tetrahydro-2H-1,3,5-thiadiazin-2-thione derivatives were performed. The 17 compounds with higher anti-epimastigote activity and lower cytotoxicity were, thereafter, screened against amastigote of Trypanosoma cruzi. Out of these 17 derivatives S-2d was selected to be assayed in vivo, because of its remarkable trypanocidal properties. To determine toxicity against J774 macrophages, a method based on quantification of cell damage, after 24 h, was used. Cell respiration, an indicator of cell viability, was assessed by the reduction of MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] to formazan. Anti-amastigote activity was estimated after 48 h by microscopic counts of May Grünwald-Giemsa-stained monolayers. Nifurtimox and benznidazole were used as reference drugs. For the in vivo experiences, mice were infected with 10(4) blood trypomastigotes and then treated during 15 days with S-2d or nifurtimox by oral route. All of the compounds were highly toxic at 100 µg/ml for macrophages and a few of them maintained this cytotoxicity even at 10 µg/ml. Of the derivatives assayed against amastigotes 3k and S-2d showed an interesting activity, that was held even at 1µg/ml. It is demonstrated that the high anti-epimastigote activity previously reported is mainly due to the non-specific toxicity of these compounds. In vivo assays assessed a reduction of parasitemia after administration of S-2d to infected mice.

Atividade de três drogas antivirais sobre os herpesvírus bovino tipos 1, 2 e 5 em cultivo celular

A atividade de três fármacos antivirais (Aciclovir [ACV], Ganciclovir [GCV] e Foscarnet [PFA]) foi testada in vitro frente aos herpesvírus bovino tipos 1 (BoHV-1), 2 (BoHV-2) e 5 (BoHV-5). Para isso, utilizou-se o teste de reducao de placas virais em cultivo celular, testando-se diferentes concentracoes dos farmacos frente a 100 doses infectantes para 50% dos cultivos celulares (DICC50) dos respectivos virus. Pelo teste de MTT (3-(4,5-Dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide), verificou-se que concentracoes inferiores a 200ƒÊg/mL dos tres antivirais resultaram em indices de viabilidade de celulas MDBK e Hep2 superiores a 80%. Com base na concentracao citotoxica para 50% das celulas (CC50) e na concentracao dos farmacos efetiva para inibir em 50% o numero de placas virais (EC50), calculou-se o indice de seletividade (IS) dos antivirais para os tres herpesvirus. Assim, o ACV demonstrou ser moderadamente ativo frente ao BoHV-1 (EC50: 112,9ƒÊg/mL e IS: 4,5), ao BoHV-2 (EC50: 114,2 ƒÊg/mL e IS: 4,5) e BoHV-5 (EC50: 96,9ƒÊg/mL e IS: 5,3). O GCV apresentou atividade moderada frente ao BoHV-2 (EC50: 33,5ƒÊg/mL e IS: 16,6) e, em menor grau, contra o BoHV-5 (EC50: 123,2ƒÊg/mL e IS: 4,5), sendo ineficaz frente ao BoHV-1 (EC50: 335,8ƒÊg/mL e IS: 1,7). O PFA apresentou atividade antiviral mais pronunciada, sendo o unico farmaco que, na concentracao de 100ƒÊg/mL, inibiu completamente a producao de placas pelos tres virus testados. O PFA foi o mais efetivo in vitro frente ao BoHV-1 (EC50: 29,5ƒÊg/mL e IS: 42,2), ao BoHV-2 (EC50: 45,2ƒÊg/mL e IS: 27,6) e ao BoHV-5 (EC50: 7,8ƒÊg/mL e IS: 160,6). Portanto, os resultados obtidos indicam que o PFA pode se constituir em um candidato para terapia experimental de infeccoes pelos herpesvirus de bovinos in vivo.

In vitro antifungal activities of leaf extracts of Lippia alba (Verbenaceae) against clinically important yeast species

Introduction There are few studies reporting the antifungal activities of Lippia alba extracts. Methods A broth microdilution assay was used to evaluate the antifungal effects of Lippia alba extracts against seven yeast species of Candida and Cryptococcus. The butanol fraction was investigated by gas chromatography-mass spectrometry. Results The butanol fraction showed the highest activity against Candida glabrata. The fraction also acted synergistically with itraconazole and fluconazole against C. glabrata. The dominant compounds in the butanol fraction were 2,2,5-trimethyl-3,4-hexanedione, 3,5-dimethyl-4-octanone and hexadecane. Conclusions The butanol fraction may be a good candidate in the search for new drugs from natural products with antifungal activity.

Solubilidade de fosfatos naturais em solução de ácido cítrico a 2%: modificação nas condições de agitação

This paper deals with a modification in the solubilization technique of natural phophates in the 2% citric acid solution. The proposed technique is as follows: 2,5 g of phosphatic material and 250 ml of 2% citric acid solution, in a 500 ml Erlenmeyer flask, are shaken for 30 minutes at 30-40 rpm. The phosphorus (P2O5) was determined by the usual method. The data obtained were compared with the conventional technique in which a Stohmann bottle is used. The natural phosphates used were: Phosphorita de Olinda (Pernambuco), Flórida Phosphate (USA) and Hiperphosphate (África). Statistical analysis was applied to the data and the following conclusions were arrived at: a) The precision is equivalent in both techniques. b) There is no significant variation between the means obtained with the two technique.

Multibacillary leprosy patients with high and persistent serum antibodies to leprosy IDRI diagnostic-1/LID-1: higher susceptibility to develop type 2 reactions

Leprosy inflammatory episodes [type 1 (T1R) and type 2 (T2R) reactions] represent the major cause of irreversible nerve damage. Leprosy serology is known to be influenced by the patient’s bacterial index (BI) with higher positivity in multibacillary patients (MB) and specific multidrug therapy (MDT) reduces antibody production. This study evaluated by ELISA antibody responses to leprosy Infectious Disease Research Institute diagnostic-1 (LID-1) fusion protein and phenolic glycolipid I (PGL-I) in 100 paired serum samples of 50 MB patients collected in the presence/absence of reactions and in nonreactional patients before/after MDT. Patients who presented T2R had a median BI of 3+, while MB patients with T1R and nonreactional patients had median BI of 2.5+ (p > 0.05). Anti-LID-1 and anti-PGL-I antibodies declined in patients diagnosed during T1R (p < 0.05). Anti-LID-1 levels waned in MB with T2R at diagnosis and nonreactional MB patients (p < 0.05). Higher anti-LID-1 levels were seen in patients with T2R at diagnosis (vs. patients with T1R at diagnosis, p = 0.008; vs. nonreactional patients, p = 0.020) and in patients with T2R during MDT (vs. nonreactional MB, p = 0.020). In MB patients, high and persistent anti-LID-1 antibody levels might be a useful tool for clinicians to predict which patients are more susceptible to develop leprosy T2R.

Métodos de concentração de minerais 2:1 secundários na fração argila visando sua identificação por difratometria de raios x

Além dos baixos teores normalmente encontrados na fração argila dos solos sob clima tropical e subtropical, o tamanho reduzido e a baixa cristalinidade dos minerais 2:1 secundários dificultam sua identificação por difratometria de raios X (DRX). Este estudo objetivou avaliar métodos químicos e físico de concentração de minerais 2:1 secundários na fração argila para facilitar a identificação por DRX, incluindo a natureza dos minerais quanto ao local de formação de cargas permanentes (lâmina tetraedral ou octaedral). Coletaram-se amostras de dois Cambissolos originados de argilito da Formação Guabirotuba na Bacia Sedimentar de Curitiba (PR): horizontes A, Bi, C1 (1,2 a 1,5 m), C2 (2,2 a 2,5 m), C3 (3,2 a 3,5 m) e C4 (4,2 a 4,5 m). Após remoção da matéria orgânica e dispersão da terra fina seca ao ar, a fração argila foi submetida a tratamentos sequenciais com ditionito-citratobicarbonato (DCB) (amostra desferrificada - remoção de óxidos de Fe pedogenéticos) e com soluções de NaOH a quente, em diferentes concentrações (0,5; 1,0; 1,5; 2,5; 3,5; 4,0; 4,5 e 5,0 mol L-1), para extração de gibbsita e caulinita, em diferentes graus. A fração argila desferrificada também foi submetida à separação física (centrifugação) em argila grossa (0,2 a 2 m) e fina (< 0,2 m). Foram realizados tratamentos auxiliares para identificar as espécies minerais 2:1 na fração argila: saturação com Mg e solvatação com etilenoglicol; saturação com K e secagem ao ar e aquecimento a 550 ºC; e saturação com Li (teste de Greene-Kelly). Os resultados mostraram que o método clássico de extração da caulinita, com solução de NaOH 5,0 mol L-1 a quente, não deve ser aplicado para concentração de minerais 2:1 secundários, pois também removeu grande parte desses minerais. O tratamento com DCB e com solução de NaOH 3,5 mol L-1 possibilitou, com maior eficiência, a concentração e identificação de minerais 2:1 secundários por DRX nas amostras dos horizontes A, Bi e C1. Nas amostras tomadas em maiores profundidades (horizontes C2, C3 e C4), devido aos maiores teores desses minerais e ao menor tamanho dos cristais (argila fina), a solução menos concentrada de NaOH (1,5 mol L-1) foi mais eficiente para esse propósito. No horizonte A, os minerais 2:1 concentraram-se na fração argila grossa, compatível com o maior grau de intemperismo desse horizonte. Identificou-se esmectita com hidroxi-Al entrecamadas nos horizontes mais superficiais (A e Bi) e esmectita nas amostras do horizonte C. A saturação com Li permitiu a identificação das esmectitas dioctaedrais montmorilonita e beidelita/nontronita. As adaptações ao métodopadrão (NaOH 5 mol L-1) favoreceram a concentração de minerais 2:1 secundários na fração argila dos solos; a concentração da solução de NaOH deve ser maior para horizontes com menor teor do mineral.

Dosimetria dos cones radiocirúrgicos Radionics de diâmetros de 5 mm a 50 mm para um feixe de 6 MV de um acelerador linear Mevatron MD digital

Os parâmetros dosimétricos de um feixe de raios X de pequeno diâmetro para um sistema de radiocirurgia comercial foram medidos em água com um detector de diodo de Si do tipo p. As razões tecido-máximo, o fator de espalhamento total e os perfis dos feixes a profundidades de 5 e 10 cm foram medidos para 17 feixes de diâmetros circulares de 5 mm a 50 mm, em incrementos de 2,5 mm. Os fatores de espalhamento totais caíram lentamente, de 0,947 para 0,888 entre os cones de 50 mm e 12,5 mm de diâmetro (variação de 7%); para os cones entre 10 mm e 5 mm de diâmetro, esta queda foi bem maior, de 0,854 para 0,666 (variação de 28%). Os valores obtidos para a relação tecido-máximo são consistentes com dados publicados. Os perfis dos feixes foram medidos nas direções x e y, e estão dentro de 0,2 mm para todos os cones entre as duas direções. A medida da largura à meia-altura se encontra dentro de 1 mm com o diâmetro nominal dos cones.

Síntese e avaliação da atividade fitotóxica de lactonas derivadas do 2,4-dimetil-8-oxabiciclo[3.2.1]-oct-6-en-3-ona

The alkene 2,4-dimethyl-8-oxabicyclo[3.2.1]-oct-6-en-3-one (3) was converted to 1,3,10-trimethyl-8-oxabicyclo[5.3.0]-dec-3-ene-2,9-dione (7) and 1,3-dimethyl-8-oxabicyclo[5.3.0]-dec-3-ene-2,9-dione (8) with a 55% overall yield in both cases. Lactones (7) and (8) were converted in two steps to 1,3,4-trimethyl-13-methylene-6-oxatricyclo[8.3.0.0(3,7)]-trideca-2,5,12-trione (12) (63%) and 1,3-dimethyl-13-methylene-6-oxatricycle[8.3.0.0(3,7)]-trideca-2,5,12-trione (13) (45% from 8). The effect of lactones (7), (8), (12), (13) and the intermediates (5) and (6), at the concentration of 250 mug mL-1, on the growth of Cucumis sativus L. and Sorghum bicolor L. was evaluated. The best results were observed for lactone (13) that caused 100% inhibition on the root growth of C. sativus and lactone (12) that inhibited 90% of the root growth for S. bicolor.