Effects of liquid extract from Plinia cauliflora fruits residues on Chinese hamsters biochemical parameters / Efeitos do extrato líquido de resíduos de frutos de Plinia cauliflora sobre os parâmetros bioquímicos de hamsters chineses

Plinia cauliflora (Mart.) Kausel, popularly known as jabuticaba, is rich in polyphenols. Phenolic compounds exhibit several biological properties, which reflect on biomarkers such as biochemical parameters. In the present study, we evaluated the plasmatic levels of glucose, total cholesterol, HDL-cholesterol, triglycerides, and uric acid of Chinese hamsters fed for 45 days with a regular diet or cholesterol-enriched diet supplemented with a liquid extract obtained from P. cauliflora fruits residues standardized in ellagic acid and total phenolic compounds. The results showed that the concentrated extract obtained from jabuticaba residues increased the glycemia of animals fed with a regular diet and reduced the plasmatic uric acid levels of animals fed with a cholesterol-enriched diet. Since hyperuricemia is considered to be a significant risk factor of metabolic disorders and the principal pathological basis of gout, the liquid extract from P. cauliflora fruits residues would be a promising candidate as a novel hypouricaemic agent for further investigation.

Plinia cauliflora (Mart.) Kausel, popularmente conhecida como jabuticaba, é rica em polifenois. Os compostos fenólicos apresentam diversas propriedades biológicas, que refletem em biomarcadores, como os parâmetros bioquímicos. No presente estudo, avaliamos os níveis plasmáticos de glicose, colesterol total, HDL-colesterol, triglicerídeos e ácido úrico em hamsters chineses alimentados por 45 dias com dieta regular ou dieta enriquecida com colesterol suplementada com extrato líquido obtido de resíduos de frutos de P. cauliflora padronizado em ácido elágico e compostos fenólicos totais. Os resultados mostraram que o extrato concentrado obtido dos resíduos de jabuticaba aumentou a glicemia dos animais alimentados com dieta regular e reduziu os níveis plasmáticos de ácido úrico dos animais alimentados com dieta rica em colesterol. Uma vez que a hiperuricemia é considerada um fator de risco significativo de distúrbios metabólicos e a principal base patológica da gota, o extrato líquido dos resíduos de frutas de P. cauliflora seria um candidato promissor como um novo agente hipouricêmico para investigação posterior.

Knockout of caspase-7 gene improves the expression of recombinant protein in CHO cell line through the cell cycle arrest in G2/M phase

BACKGROUND: Chinese hamster ovary cell line has been used routinely as a bioproduction factory of numerous biopharmaceuticals. So far, various engineering strategies have been recruited to improve the production efficiency of this cell line such as apoptosis engineering. Previously, it is reported that the caspase-7 deficiency in CHO cells reduces the cell proliferation rate. But the effect of this reduction on the CHO cell productivity remained unclear. Hence, in the study at hand the effect of caspase-7 deficiency was assessed on the cell growth, viability and protein expression. In addition, the enzymatic activity of caspase-3 was investigated in the absence of caspase-7. RESULTS: Findings showed that in the absence of caspase-7, both cell growth and cell viability were decreased. Cell cycle analysis illustrated that the CHO knockout (CHO-KO) cells experienced a cell cycle arrest in G2/M phase. This cell cycle arrest resulted in a 1.7-fold increase in the expression of luciferase in CHO-KO cells compared to parenteral cells. Furthermore, in the apoptotic situation the enzymatic activity of caspase-3 in CHO-KO cells was approximately 3 times more than CHO-K1 cells. CONCLUSIONS: These findings represented that; however, caspase-7 deficiency reduces the cell proliferation rate but the resulted cell cycle arrest leads to the enhancement of recombinant protein expression. Moreover, increasing in the caspase-3 enzymatic activity compensates the absence of caspase-7 in the caspase cascade of apoptosis.

Caspase-7 deficiency in Chinese hamster ovary cells reduces cell proliferation and viability

BACKGROUND: Chinese hamster ovary (CHO) cells are the most commonly used mammalian host cell In the commercial-scale production of biopharmaceutical proteins. Modification of genes involved in apoptosis may improve the productivity of CHO cells. Executive caspases, including caspases 3 and 7, play critical roles in apoptosis. The effects of the ablation of the caspase 7 gene on proliferation and viability of CHO cells remains unknown. In this study, we applied clustered regularly interspaced short palindromic repeat (CRISPR/Cas9) to target caspase 7 gene of CHO K1 cell via all in one and homology targeted integration strategies. Consequently, the effect of caspase 7 deficiency on cell proliferation, viability, and apoptosis was studied by MTT assay and flow cytometry. RESULTS: Findings of gel electrophoresis, western blotting, and sequencing confirmed the caspase 7 gene silencing in CHO cells (CHO-KO). Proliferation assay revealed that caspase 7 deficiency in CHO cells resulted in the reduction of proliferation in various CHO-KO clones. Besides, the disruption of caspase 7 had negative effects on cell viability in exposure with NaBu which confirmed by MTT assay. Results of flow cytometry using Anexin V/PI demonstrated that Nabu treatment (11 mM) declined the percentage of live CHO-K1 and CHO-KO cells to 70.3% and 5.79%. These results verified that the CHO-K1 cells were more resistant to apoptosis than CHO-KO, however most of CHO-KO cells undergone early apoptosis (91.9%) which seems to be a fascinating finding. CONCLUSION: These results reveal that caspase 7 may be involved in the cell cycle progression of CHO cells. Furthermore, it seems that targeting caspase 7 is not the ideal route as it had previously been imagined within the prevention of apoptosis but the relation between caspase 7 deficiency, cell cycle arrest, and the occurrence of early apoptosis will require more investigation.

Discovery of the ARP2 protein as a determining molecule in tumor cell death

Cancer is a multifactorial disease that constitutes a serious public health problem worldwide. Prostate cancer advanced stages are associated with the development of androgen-independent tumors and an apoptosis-resistant phenotype that progresses to metastasis. By studying androgen-independent lymphoid nodule carcinoma of the prostate (LNCaP) cells induced to apoptosis by serum elimination, we identified the activation of a non-selective cationic channel of 23pS conductance that promotes incoming Ca2+ currents, as well as apoptosis final stages. arp2cDNA was isolated and identified to be of the same cell type, and mRNA was expressed in Xenopus laevis oocytes, which was found to be associated with the activation of incoming Ca2+ currents and induction to apoptosis. cDNA, which encodes the ARP2 protein, was overexpressed in LNCaP cells and Chinese hamster ovary cells, which induced apoptosis. Our evidence suggests that protein ARP2 overexpression and transit to the cell membrane allows an increased Ca2+ incoming current that initiates the apoptosis process in epithelial-type cells whose phenotype shows resistance to programmed cell death.

Bats and zoonotic viruses: can we confidently link bats with emerging deadly viruses?

An increasingly asked question is 'can we confidently link bats with emerging viruses?'. No, or not yet, is the qualified answer based on the evidence available. Although more than 200 viruses - some of them deadly zoonotic viruses - have been isolated from or otherwise detected in bats, the supposed connections between bats, bat viruses and human diseases have been raised more on speculation than on evidence supporting their direct or indirect roles in the epidemiology of diseases (except for rabies). However, we are convinced that the evidence points in that direction and that at some point it will be proved that bats are competent hosts for at least a few zoonotic viruses. In this review, we cover aspects of bat biology, ecology and evolution that might be relevant in medical investigations and we provide a historical synthesis of some disease outbreaks causally linked to bats. We provide evolutionary-based hypotheses to tentatively explain the viral transmission route through mammalian intermediate hosts and to explain the geographic concentration of most outbreaks, but both are no more than speculations that still require formal assessment.

Episiotomy healing assessment: Redness, Oedema, Ecchymosis, Discharge, Approximation (REEDA) scale reliability / Avaliação da cicatrização da episiotomia: confiabilidade da escala REEDA (Redness, Oedema, Ecchymosis, Discharge, Approximation) / Evaluación de la curación de episiotomía: confiabilidad de la escala de Enrojecimiento, Edema, Equimosis, Drenaje, Aproximación (REEDA)

OBJECTIVE: to analyse the Redness, Oedema, Ecchymosis, Discharge, Approximation (REEDA) scale reliability when evaluating perineal healing after a normal delivery with a right mediolateral episiotomy. METHOD: observational study based on data from a clinical trial conducted with 54 randomly selected women, who had their perineal healing assessed at four time points, from 6 hours to 10 days after delivery, by nurses trained in the use of this scale. The kappa coefficient was used in the reliability analysis of the REEDA scale. RESULTS: the results indicate good agreement in the evaluation of the discharge item (0.75< Kappa ≥0.88), marginal and good agreement in the first three assessments of oedema (0.16< Kappa ≥0.46), marginal agreement in the evaluation of ecchymosis (0.25< Kappa ≥0.42) and good agreement regarding redness (0.46< Kappa ≥0.66). For the item coaptation, the agreement decreased from excellent in the first assessment to good in the last assessment. In the fourth evaluation, the assessment of all items displayed excellent or good agreement among the evaluators. CONCLUSION: the difference in the scores among the evaluators when applying the scale indicates that this tool must be improved to allow an accurate assessment of the episiotomy healing process. .

OBJETIVO: analisar a confiabilidade da escala REEDA (Redness, Oedema, Ecchymosis, Discharge, Approximation) para avaliar a cicatrização do períneo após parto vaginal com episiotomia médio-lateral direita. MÉTODO: estudo observacional, baseado em dados coletados em ensaio clínico, conduzido com 54 mulheres, selecionadas aleatoriamente. As mesmas tiveram o processo de cicatrização perineal avaliado em quatro momentos (de 6 horas a 10 dias após o parto), por enfermeiras treinadas para o uso da escala. O coeficiente kappa foi usado para análise de confiabilidade da escala REEDA. RESULTADOS: os resultados indicam bom nível de concordância na avaliação do item secreção (0,75< Kappa ≥0,88), concordância boa e marginal em relação ao item equimose (0,25< Kappa ≥0,42), e bom nível de concordância em relação à hiperemia (0,46< Kappa ≥0,66). O nível de concordância referente à avaliação do item coaptação diminuiu de excelente, na primeira avaliação, para bom, na última avaliação. CONCLUSÃO: a diferença entre as pontuações atribuídas pelas avaliadoras na aplicação da escala indica que o instrumento precisa ser melhorado, para permitir avaliações mais precisas do processo de cicatrização da episiotomia. .

OBJETIVO: analizar la confiabilidad de la escala de Enrojecimiento, Edema, Equimosis, Drenaje, Aproximación (REEDA) en la evaluación de la curación perineal tras parto normal con episiotomía mediolateral derecha. MÉTODO: estudio observacional con base en datos de un ensayo clínico conducido con 54 mujeres elegidas de forma aleatoria, con evaluación de su curación perineal en cuatro momentos, entre 6 horas y 10 días después del parto, por enfermeras capacitadas en el uso de esta escala. El coeficiente de kappa fue utilizado en el análisis de confiabilidad de la escala REEDA. RESULTADOS: los resultados indican buena concordancia en la evaluación del ítem drenaje (0,75< Kappa ≥0,88), concordancia marginal y buena en las primeras tres evaluaciones de edema (0,16< Kappa ≥0,46), concordancia marginal en la evaluación de equimosis (0,25< Kappa ≥0,42) y buena concordancia sobre enrojecimiento (0,46< Kappa ≥0,66). Para el ítem coaptación, la concordancia disminuyó de excelente en la primera evaluación hasta buena en la última. En el cuarto momento, la evaluación de todos los ítems mostró concordancia excelente o buena entre los evaluadores. CONCLUSIÓN: la diferencia en las notas entre los evaluadores en la aplicación de la escala indica que esta herramienta debe ser mejorada para permitir una evaluación correcta del proceso de curación de la episiotomía. .

Antibody recognition of Plasmodium falciparum infected red blood cells by symptomatic and asymptomatic individuals in the Brazilian Amazon

In the Amazon Region, there is a virtual absence of severe malaria and few fatal cases of naturally occurring Plasmodium falciparum infections; this presents an intriguing and underexplored area of research. In addition to the rapid access of infected persons to effective treatment, one cause of this phenomenon might be the recognition of cytoadherent variant proteins on the infected red blood cell (IRBC) surface, including the var gene encoded P. falciparum erythrocyte membrane protein 1. In order to establish a link between cytoadherence, IRBC surface antibody recognition and the presence or absence of malaria symptoms, we phenotype-selected four Amazonian P. falciparum isolates and the laboratory strain 3D7 for their cytoadherence to CD36 and ICAM1 expressed on CHO cells. We then mapped the dominantly expressed var transcripts and tested whether antibodies from symptomatic or asymptomatic infections showed a differential recognition of the IRBC surface. As controls, the 3D7 lineages expressing severe disease-associated phenotypes were used. We showed that there was no profound difference between the frequency and intensity of antibody recognition of the IRBC-exposed P. falciparum proteins in symptomatic vs. asymptomatic infections. The 3D7 lineages, which expressed severe malaria-associated phenotypes, were strongly recognised by most, but not all plasmas, meaning that the recognition of these phenotypes is frequent in asymptomatic carriers, but is not necessarily a prerequisite to staying free of symptoms. .

Kazal-type serine proteinase inhibitors in the midgut of Phlebotomus papatasi

Sandflies (Diptera: Psychodidae) are important disease vectors of parasites of the genus Leishmania, as well as bacteria and viruses. Following studies of the midgut transcriptome of Phlebotomus papatasi, the principal vector of Leishmania major, two non-classical Kazal-type serine proteinase inhibitors were identified (PpKzl1 and PpKzl2). Analyses of expression profiles indicated that PpKzl1 and PpKzl2 transcripts are both regulated by blood-feeding in the midgut of P. papatasi and are also expressed in males, larva and pupa. We expressed a recombinant PpKzl2 in a mammalian expression system (CHO-S free style cells) that was applied to in vitro studies to assess serine proteinase inhibition. Recombinant PpKzl2 inhibited α-chymotrypsin to 9.4% residual activity and also inhibited α-thrombin and trypsin to 33.5% and 63.9% residual activity, suggesting that native PpKzl2 is an active serine proteinase inhibitor and likely involved in regulating digestive enzymes in the midgut. Early stages of Leishmania are susceptible to killing by digestive proteinases in the sandfly midgut. Thus, characterising serine proteinase inhibitors may provide new targets and strategies to prevent transmission of Leishmania.

Development of potency assays for a plasmid containing vascular endothelial growth factor 2 / Desarrollo de la potencia de los ensayos para un plásmido que contiene factor 2 de crecimiento endotelial vascular

We have developed analytical methods to measure the biological functions of pVGI.1(VEGF2), a naked plasmid DNA product containing vascular endothelial growth factor 2 used in clinical trials for coronary artery diseases (CAD) and peripheral artery diseases (PAD). After being injected into muscles, vascular endothelial growth factor 2 (VEGF-2), presumably expressed in muscle tissues, binds to the endothelial cell receptors VEGFR2 or VEGFR3, triggering the downstream responses including cell proliferation and vascularization. As it is important to make sure clinical material is biological active, we developed a quantitative assay first to measure the receptor binding activity of the pVGI.1(VEGF2) gene product expressed by the transfected host cells, and then a qualitative assay to confirm the cell proliferation promoting activity of the expressed protein. In both assays the signals were plotted directly against input DNA concentrations used to transfect the host cells. We confirmed specificity for both assays. In addition, we demonstrated acceptable levels of spike recovery (86.7-116 percent), precision (largest relative standard deviation (RSD)=19.3 percent), linearity and range (60-140 percent relative potency, 15 - 35 ug/mL) for the quantitative assay. We intend to use the potency assays for routine lot release and stability studies.

Expression of Hepatitis B virus surface antigen (HBsAg) from genotypes A, D and F and influence of amino acid variations related or not to genotypes on HBsAg detection

The impact of hepatitis B virus (HBV) genotypes on the sensitivity of surface antigen (HBsAg) detection assays has been poorly investigated. Here, plasmids carrying consensus or variant coding sequences for HBV surface proteins from genotypes A, D and F, were constructed. HBsAg levels were evaluated in medium and extracts of transfected CHO cells by a commercial polyclonal-based assay. We show that HBsAg detection values of consensus forms from genotypes D and F were, respectively, 37 percent and 30 percent lower than those obtained by genotype A. However, the presence of two single variations, T143M in genotype A, and T125M in genotype D, produced a decrease of 44 percent and an increase of 34 percent, respectively, on HBsAg mean values in comparison with their consensus forms. In conclusion, HBsAg detection levels varied among HBV genotypes. However, unique amino acid substitutions not linked to genotypes, such as T125M and T143M described here, should have more implications in HBV immunological diagnostics than the set of variations characteristic of each HBV genotype.

An enhancer/promoter combination strengthens the expression of blood-coagulation factor VIII in non-viral expression vectors

We explored the potential of fusion of hepatic locus control region 1 (HCR-1) with HCR-2 to express B-domain-deleted human factor VIII (FVIII) in four cell lines. B-domain-deleted human FVIII expression was controlled by HCR-1/HCR-2, followed by liver specific and ubiquitous promoters. Chimera enhancer HCR-1/HCR-2, followed by cytomegalovirus (CMV) promoter, gave 2-fold more FVIII expression in all cell lines (105.6 ± 2.8 for Hek-293, 68.8 ± 3.8 for HepG2, 34.8 ± 1.3 for CHO, and 27.2 ± 1.6 ng-mL-1-106 cells-1 for L.N.) when compared to the vector with CMV alone (54.8 ± 3.3 for Hek-293, 32.4 ± 1.2 for HepG2, 18.6 ± 1.1 for CHO, and 10.1 ± 1.7 ng-mL-1-106 cells-1 for L.N.). Elongation factor 1-α gene and human CMV promoters were more efficient than the promoters from the human α-1-antitrypsin gene, and fviii was less efficient in hepatic cell lines. HCR-1/HCR-2, followed by strong promoters, increases FVIII expression in vitro. Our results underscore the importance of cis sequences for enhancing in vitro FVIII expression; this may be helpful for designing new strategies to improve heterologous expression systems.

Evaluation of the role of the Endoplasmic Reticulum-Golgi transit in the biogenesis of peroxisomal membrane proteins in wild type and peroxisome biogenesis mutant CHO cells

Peroxisomes are thought to be formed by division of pre-existing peroxisomes after the import of newly synthesized proteins. However, it has been recently suggested that the endoplasmic reticulum (ER) provides an alternative de novo mechanism for peroxisome biogenesis in some cells. To test a possible role of the ER-Golgi transit in peroxisome biogenesis in mammalian cells, we evaluated the biogenesis of three peroxisomal membrane proteins (PMPs): ALDRP (adrenoleukodystrophy related protein), PMP70 and Pex3p in CHO cells. We constructed chimeric genes encoding these PMPs and green fluorescent protein (GFP), and transiently transfected them to wild type and mutant CHO cells, in which normal peroxisomes were replaced by peroxisomal membrane ghosts. The expressed proteins were targeted to peroxisomes and peroxisomal ghosts correctly in the presence or absence of Brefeldin A (BFA), a drug known to block the ER-Golgi transit. Furthermore, low temperature did not disturb the targeting of Pex3p-GFP to peroxisomes. We also constructed two chimeric proteins of PMPs containing an ER retention signal "DEKKMP": GFP-ALDRP-DEKKMP and myc- Pex3p-DEKKMP. These proteins were mostly targeted to peroxisomes. No colocalization with an ER maker was found. These results suggest that the classical ER-Golgi pathway does not play a major role in the biogenesis of mammalian PMPs.

Study of DNA damage induced by dental bleaching agents in vitro

Clareamento dental é um procedimento simples e conservador para restaurar esteticamente a cor de dentes vitais e não-vitais. Entretanto, alguns estudos têm demonstrado o risco de dano tecidual a partir do contato desses agentes com a mucosa bucal. Neste presente estudo, o potencial genotóxico associado à exposição aos agentes clareadores dentais foi avaliado pelo teste de células individualizadas em gel (teste do cometa) in vitro. Células de ovário de hamster chinês (CHO) in vitro foram expostas a seis agentes clareadores dentais comercialmente disponíveis (Clarigel Gold – Dentsply; Whitespeed – Discus Dental; Nite White – Discus Dental; Magic Bleaching – Vigodent; Whiteness HP – FGM e Lase Peroxide – DMC). Os resultados mostraram que todos os agentes clareadores testados contribuíram para os danos no DNA, como demonstrado pela média do momento da cauda, sendo o efeito mais forte observado na mais alta dose de peróxido de hidrogênio (Whiteness HP e Lase Peroxide, na concentração de 35%). Por outro lado, Magic Bleaching (Vigodent) induziu o menor nível de quebras no DNA. Os controles negativo e positivo apresentaram ausência e presença de danos no DNA, respectivamente. Em suma, esses resultados sugerem que os agentes clareadores dentais podem ser um fator que aumenta o nível de danos no DNA. Uma concentração de peróxido de hidrogênio mais elevada produziu atividades nocivas mais severas no genoma como detectado pelo teste do cometa.

Ação do licopeno na proteção contra danos induzidos no DNA in vivo e in vitro / Action of lycopene in the protection against damage induced in DNA in vivo and in vitro

O licopeno é um pigmento natural sintetizado por plantas e microorganismos, e encontrado principalmente no tomate. É um isômero acíclico do beta-caroteno sem atividade pró-vitamínica­-A, sendo um dos mais potentes agentes antioxidantes. Diversos pesquisadores têm demonstrado o efeito protetor do licopeno contra danos no DNA e sobre a carcinogênese quicamente induzida, embora os mecanismos envolvidos nesses processos não estejam, ainda totalmente esclarecidos. Assim, o presente estudo objetivou avaliar o potencial quimioprotetor do licopeno contra danos no DNA e sobre a hepaticarcinogênese em roedores. O efeito anticarcinogênico do licopeno em figado de ratos foi avaliado utilizando-se os focos GST-P positivos (modelo de hepatocarcinogênese de média duração proposto por Ito et al., 1988) como biomarcadores de lesões pré-neoplásicas. Para avaliação do efeito antigenotóxico e antimutagênico do carotenóide, bem como de seu possível mecanismo de ação, foram utilizados, respectivamente, o teste do cometa e o teste do micronúcleo em duas linhagens celulares in vitro: células de ovário de hamster chinês (CHO) e células de hepatoma humano (HepG2). Mutágenos de ação direta (peróxido de hidrogênio, oxido de 4-nitroquinolina - 4NQO e metil metanosulfonato - MMS) e indireta (dietilnitrosamina -DEN), foram utilizados 10 indutores de danos no DNA in vitro. Os resultados mostraram que o licopeno, na concentração 300 ppm, reduziu significativamente os danos no DNA induzidos pela DEN na etapa de iniciação da hepatocarcinogênese de rato, embora não tenha sido observada redução do número e área dos focos GST-P-positivos. Os resultados dos experimentos in vitro mostraram que o tratamento prévio e simultâneo com licopeno (10, 25, e 50 miuM) foi eficaz em reduzir os níveis de danos no DNA induzidos pelo H202 e pela DEN em células HepG2, quando avaliados tanto teste do cometa como do micronúcleo.

Fluoride does not induce DNA breakage in Chinese hamster ovary cells in vitro

O flúor tem sido amplamente usado na Odontologia, pois é um agente profilático efetivo e específico contra a cárie dentária. Entretanto, o flúor em excesso pode representar perigos à saúde humana, especialmente por causar agressão ao material genético. Testes de genotoxicidade representam uma importante parte da pesquisa do câncer para a avaliação de risco de possíveis carcinógenos. Neste presente estudo, danos ao DNA associados à exposição ao flúor foram avaliados pelo teste de células individualizadas em gel de agarose (teste do cometa) in vitro. Células de ovário de hamster chinês foram expostas ao fluoreto de sódio (NaF) nas concentrações finais de 7 a 100 µg/ml, durante 3 h, a 37ºC. Os resultados mostraram que o NaF não contribuiu para os danos no DNA em todas as concentrações testadas, conforme demonstrado pelas médias do momento da cauda e da intensidade da cauda dos cometas. Esses achados são clinicamente importantes, uma vez que representam uma importante contribuição para a correta avaliação do potencial risco à saúde associada à exposição aos agentes odontológicos.

Protective effect of butylated hydroxytoluene (BHT) against the clastogenic acitivity of cadmium chloride and potassium dichromate in hamster ovary cells

The effect of butylated hydroxytoluene (BHT), a widely used food additive, on chromosomal alterations induced by cadmium chloride (CC) and potassium dichromate (PD) in Chinese hamster ovary (CHO) cells was studied both at metaphase and anaphase-telophase. CHO cells were cultured for 15-16 h in the presence of PD (6.0, 9.0 or 12.0 mM), BHT (1.0 mg/ml), or PD plus BHT as well as CC (0.5, 1.0 and 2.0 mM), BHT or CC plus BHT for the analysis of chromosomal aberrations. To perform the anaphase-telophase test, cells were cultured in cover glasses and treated 8 h before fixation with the same chemicals. An extra dose of CC (4 mM) was used in this test. Both metal salts significantly increased chromosomal aberration frequencies in relation to untreated controls, and to DMSO- and BHT-treated cells. Post-treatment with BHT decreased the yield of chromosomal damage in relation to treatments performed with CC and PD. However, chromosomal aberration frequencies were significantly higher than those of the controls. In the anaphase-telophase test, CC significantly increased the yield of lagging chromosomes with the four doses employed and the frequency of lagging fragments with the highest dose. In combined treatments of CC and BHT, frequencies of the two types of alterations decreased significantly in relation to the cells treated with CC alone. No significant variation was found in the frequencies of chromatin bridges. Significant increases of numbers of chromatin bridges, lagging chromosomes and lagging fragments were found in cells treated with PD. The protective effect of BHT in combined treatments was evidenced by the significant decrease of chromatid bridges and lagging chromosomes in relation to PD-treated cells. Whereas BHT is able to induce chromosomal damage, it can also protect against oxidative damage induced by other genotoxicants.

Efecto in vitro de prazicuantel sobre la actividad de Giardia intestinalis / In vitro effects of praziquantel over the trophozoites of Giardia intestinalis

Se realizó un estudio in vitro para conocer el efecto farmacológico de prazicuantel sobre los trofozoítos de Giardia intestinalis cepa P-1. Después de cultivarlos axénicamente, con cinco diferentes concentraciones de prazicuantel (de 0.32 hasta 1.62 nM/mL) durante 24 h a 37ºC, la viabilidad y la CI50 evaluada por la captación de colorante fluorogénico con citometría de flujo mostró un desplazamiento logarítmico de 10º a 10 a la tercera lo que correspondió a una concentración de 1.28 nM/mL. La incorporación de H3 metil-timidina como parámetro de crecimiento celular a 50 por ciento alcanzó 1.20 nM/mL de prazicuantel y el efecto citotóxico calculado por la capacidad de lisar células CHO (células de ovario de hámster chino) marcados con Cr51 se observó para la CI50 en una concentración de 1.05 nM/mL. Con estos tres parámetros se puede inferir qué viabilidad a 50 por ciento se observó a concentraciones más altas de prazicuantel comparadas con la capacidad para dividirse, así como el efecto citolítico, en donde la concentraciones más altas de prazicuantel comparadas con la capacidad para dividirse, así como el efecto citolítico, en donde la concentración de prazicuantel fue la más baja a lo que se atribuye la cualidad de apagar radicales libres, sin embargo, esto no fue proporcional al incrementar la concentración suponiéndose una importante capacidad detoxificante en Giardia. Se concluye que prazicuantel desarrolló actividad farmacológica en protozoarios, lo que le hace susceptible de emplearse contra la giardiasis

The effects of 3-aminobenzamide and aphidicolin on x-ray-induced chromosomal aberrations in cycling and non-cycling dowwn lymphocytes

Amphidicolin (APC) e 3-aminobenzamide (3AB) foram utilizados para elucidar o papel de processos de reparo de DNA no aumento de aberraçöes induzidas por Raio-X em culturas de linfócitos de pacientes com Síndrome de Down, comparadas com controles normais. Estimulados por fitohemaglutinina (PHA) (Fase G1), os controles normais mostraram um aumento significativo na produçäo de dicêntricos, mas näo de acêntricos. Em culturas de Downs as células estimuladas mostraram um aumento significativo na produçäo de dicêntricos e acêntricos. O efeito de APC, em contraste, foi menos pronunciado sem estimulaçäo. Na condiçäo estimulado, como para 3AB, o efeito de APC foi maior em controles normais. O processamento diferencial de dados genéticos induzidos por Raio-X em linfócitos periferais de Downs, é sensível a presença de APL e 3AB. É provável que ambos, DNA polymerase Ó e poly (ADP-ribose) polimerase tem comportamento diferenciado intrínsico nos linfócitos de Downs sensíveis a PHA

Appearance of Holes in sub-telomeric regions of human and chinese hamster ovary cell chromosomes due to prolonged incubation in T-banding buffer, followed by giemsa staining

A incubaçäo prolongada de cromossomos humanos e de células de ovário de hamster Chinês (CHO) em tampäo bandeamento T quente, induz o aparecimento de pequenos orifícios na área subtelomérica e nas regiöes paracêntricas de cromátides irmäs. Orifícios induzidos nos cromossomos também foram observados em células CHO poliplóides e endoreduplicadas. Microscopia de reflexäo mostrou estruturas cromossômicas escuras, vazias e bem definidas. Esses orifícios podem ser indicaçäo de que porçöes de segmentos cromossômicos säo removidos especificamente através deste método, o qual se deve a uma composiçäo molecular segmentária