Abstract Due to rising concerns for environmental and human health, many toxic compounds, such as auxin-based herbicides, have been tested in relation their toxicity effect. Especially cyto- and phytotoxic assays have been performed on a number monocot and eudicot plant species. In these approaches the toxicity level of the auxin is compared to a positive control – usually a commercial compound with known effects and chemical similarity to the target compound. However, many target compounds still lack an indication of an adequate positive control. Here, we evaluate the phytotoxic and cytotoxic effect of the auxins 2,4-dichlorophenoxyacetic acid, dicamba, and picloram in order test their potential use as positive controls. All tested auxinic herbicides showed clastogenic and aneugenic effect mechanisms. The results indicate 2,4-dichlorophenoxyacetic acid as the most phyto- and cytotoxic in the discontinuous method in Lactuca sativa L. and Allium cepa L., and also in the continuous method in A. cepa. Thus, we suggest 2,4-dichlorophenoxyacetic acid as a positive control for future mutagenesis studies involving new auxins. For studies with L. sativa in continuous method, we recommend the auxin picloram as positive control as this one was the only one which allowed the development of roots.

Resumo Pigmentos inorgânicos foram preparados com estrutura espinélio para aplicações em revestimentos cerâmicos. Pigmentos com composição CoCr2O4 e Co0,8Zn0,2Cr2O4 foram sintetizados por uma rota química usando gelatina de uso farmacêutico como precursor orgânico. Foram investigadas a influência da dopagem e a temperatura de tratamento térmico na coloração dos pigmentos e dos esmaltes cerâmicos. Os materiais foram caracterizados por análise termogravimétrica, difração de raios X, microscopia eletrônica de varredura, espectroscopia por energia dispersiva, espectroscopia na região do UV-visível e colorimetria. Os pós apresentaram estrutura espinélio a partir de 500 °C, com formação de fase secundária residual de Cr2O3 nas amostras Co0,8Zn0,2Cr2O4 tratadas termicamente a 500 e 1000 °C. Os pigmentos e os esmaltes preparados apresentaram cores em tons de azul esverdeado para as amostras CoCr2O4 e verde para a amostra Co0,8Zn0,2Cr2O4. Os resultados confirmaram a efetividade da rota de síntese utilizada para produzir óxidos com estrutura espinélio.

Abstract Inorganic pigments were prepared with spinel structure for applications in ceramic tiles. Pigments with composition CoCr2O4 and Co0.8Zn0.2Cr2O4 were synthesized by a chemical route using gelatin for pharmaceutical use as an organic precursor. The influences of doping and thermal treatment temperature on pigment and ceramic glaze color were investigated. The materials were characterized by thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, dispersive energy spectroscopy, spectroscopy in the UV-visible region and colorimetry. The powders treated at 500 °C presented spinel structure, with the formation of residual secondary phase of Cr2O3 in samples Co0.8Zn0.2Cr2O4 heat-treated at 500 and 1000 °C. The prepared pigments and glazes presented blue-green colors for the samples CoCr2O4 and green color for the sample Co0.8Zn0.2Cr2O4. The results confirmed the effectiveness of the synthesis route used to produce oxides with a spinel structure.

The phytochemical investigation of the alkaloid-rich fraction obtained from the leaves of Guatteria pogonopus Mart. (Annonaceae) allowed the isolation and identification for the first time in this species of: (+)-nornuciferine (1), a mixture of 1 and (+)-anonaine (2), (+)-isocorydine (3), (+)-nuciferine (4), (+)-roemerine (5), (-)-tetrahydropseudocolumbamine (6), a mixture of 6, liriodenine (9) and lysicamine (10), a mixture of 1,2,9-trimethoxy-10-hydroxyaporphine (7) and bulbocapnine (8), 9, 10, and (+)-N-methyllindicarpine (11). Compounds 6, 7, 8, and 11 have not been previously reported in the family Annonaceae. Furthermore, the formerly synthetic 1,2,9-trimethoxyaporfin-10-ol (7) is described for the first time as a natural aporphine alkaloid herein. The chemical structures were established by 1D and 2D NMR as well as in comparison with data previously reported in the literature. The cytotoxic activity of the alkaloids was evaluated against tumor (B16-F10, HepG2, HL-60, and K562) and non-tumor (PBMC) cell lines. Alkaloid 1 presented significant activity against HepG2 cell lines with IC50 of 9.60 µmol L-1 while the mixture of 6, 9 and 10 displayed strong cytotoxic activity against HL-60 and K562 cell lines with IC50 values of 3.41 an 8.50 µmol L-1, respectively.

Um mecanismo alternativo para a indução assimétrica 1,4, na adição estereosseletiva da (R)-pantolactona ao 2-fenilpropilceteno foi investigado teoricamente. Um mecanismo envolvendo uma transferência de hidrogênio intermolecular foi proposto, que considera a participação ativa da dimetiletilamina e seu íon como agentes de transferência de hidrogênio. No primeiro passo, uma molécula de dimetiletilamina neutra interage com o anel de 7 membros do enol intermediário. Uma interação ácido-base específica é estabelecida entre o grupo hidroxila do enol e o átomo de nitrogênio da amina. A amina neutra é básica o suficiente para remover o hidrogênio. Uma outra molécula de amina protonada doa seu hidrogênio à ligação dupla C=C, para fornecer os produtos desejados. A estereoquímica foi definida pelo modo como as moléculas de amina neutra e protonada aproximam-se do enol. O excesso diasteroisomérico encontrado concorda com o dado experimental [para (S, R) e (R, R) é de 99:1].

An alternative mechanism for the 1,4-assymmetric induction in the stereoselective addition of (R)-pantolactone to 2-phenylpropylketene was theoretically investigated. A mechanism involving an intermolecular proton transfer assisted by two amine molecules was proposed, which considered the active participation of the dimethylethylamine and its ion as proton transfer agents. In the first step, a neutral dimethylethylamine interacts with the seven-membered ring of the enol intermediate. A specific acid-base interaction is established between the hydroxyl group of the enol and the nitrogen atom of the dimethylethylamine. The neutral dimethylethylamine is basic enough to remove the proton. Another protonated dimethylethylamine is considered to donate its proton to the C=C double bond to give the desired products. The stereochemical outcome was defined by the way that the neutral and protonated dimethylethylamine approached to the enol. The diastereoisomeric ratio found is in good agreement with experiments [for (S, R) and (R, R) it is 99:1].

OBJETIVO: Avaliar o metabolismo da glicose em pacientes acromegálicos antes e após o tratamento com octreotide LAR. PACIENTES E MÉTODOS: Este foi um estudo longitudinal e prospectivo com 30 pacientes do ambulatório de pesquisa em acromegalia do Serviço de Endocrinologia do Hospital Universitário Clementino Fraga Filho da Universidade Federal do Rio de Janeiro (HUCFF/UFRJ). Eles foram submetidos à avaliação clínica e laboratorial com dosagens de hormônio do crescimento (GH), fator de crescimento semelhante à insulina tipo I (IGF-I), insulina, pró-insulina, peptídeo C, hemoglobina glicosilada (HbA1c), proteína de ligação do IGF tipo 1 (IGFBP-1) e a um teste oral de tolerância à glicose (TOTG), antes e após seis meses de tratamento com octreotide LAR. Foi aplicado o teste dos postos sinalizados de Wilcoxon e o critério de determinação de significância adotado foi o nível de 5%. RESULTADOS: Encontraram-se 16 pacientes (54%) com tolerância normal à glicose, sete (23%) com intolerância à glicose e sete (23%) com diabetes melito (DM). Doze pacientes completaram os seis meses de tratamento, sendo que houve piora da tolerância à glicose em três e piora do controle glicêmico dos dois pacientes diabéticos. Houve aumento da circunferência abdominal (p = 0,03) e queda do GH (p = 0,04), % IGF-I acima do limite superior do valor de referência (%LSVR) (p = 0,001), insulina (p = 0,019), peptídeo C (p = 0,002) e do modelo de avaliação homeostática (HOMA-IR) (p = 0,039). CONCLUSÕES: Nesta série, o tratamento com octreotide LAR acarretou piora da tolerância à glicose em três pacientes não-diabéticos e piora do controle glicêmico em dois diabéticos, apesar da diminuição da resistência insulínica (RI).

AIM OF THE STUDY: To evaluate the glucose metabolism in acromegalic patients before and after treatment with octreotide LAR. PATIENTS AND METHODS: This was a prospective and longitudinal study involving 30 patients from the acromegaly research outpatient clinic of the Endocrinology unit of the HUCFF/UFRJ. They underwent clinical and laboratorial evaluations, with measurements of growth hormone (GH), insulin-like growth factor type I (IGF-I), insulin, proinsulin, C peptide, glycosylated hemoglobin (HbA1c), IGF binding protein type 1 (IGFBP-1) and glucose, during oral glucose tolerance test (OGTT), before and after six months of treatment with octreotide LAR. The Wilcoxon signed-rank test was used and values of 5% were considered statistically significant. RESULTS: We found 16 (54%) patients with normal glucose tolerance, 7 (23%) with impaired glucose tolerance and 7 (23%) diabetics. Twelve patients completed the six-month treatment, out of which three showed worsening of glucose tolerance and two (diabetics) had worse blood glucose control. Whereas there was an increase in waist circumference (p=0.03), there was a decrease in GH (p=0.04), with %IGF-I above the upper limit of reference values (% ULRV) [p=0.001], insulin (p=0.019), C peptide levels (p=0.002) and homeostatic model assessment (HOMA-IR) [p=0.039]. CONCLUSIONS: In this series, treatment with octreotide LAR led to a worsening of glucose tolerance in three non-diabetic patients and worsened glycemic control in two diabetics, in spite of reducing insulin resistance.

A rotating cylinder reactor was designed for the synthesis of niobium carbide powders at 1173 K. Niobium carbide, NbC, was prepared by carbothermal reduction starting from commercial niobium pentoxide powders. The reactor was heated using a custom-made, two-part, hinged, electric furnace with programmable temperature control. The design and operational details of the reactor are presented. The longitudinal temperature gradient inside the reactor was determined. Total reaction time was monitored by a gas chromatograph equipped with an FID detector for determination of methane concentrations. The results show that time of reaction depended on rotation speed. NbC was also prepared in a static-bed alumina reactor using the same conditions as in the previous case. The niobium carbide powders were characterized by X-ray diffraction and compared with commercially available products. Morphological, particle size distribution and surface area analyses were obtained using SEM, LDPS and BET, respectively. Therefore, the present study offers a significant technological contribution to the synthesis of NbC powders in a rotating cylinder reactor.