Técnicas histopatológicas no diagnóstico de criptococose por Cryptococcus deficiente de cápsula: relato de caso

Caso de criptococose por Cryptococcus deficiente de cápsula, no qual cultivo do espécime clínico e pesquisa do antígeno capsular no líquor e soro foram negativos. As técnicas histopatológicas foram: Hematoxilina-eosina, Grocott, Mucicarmim de Mayer e Fontana-Masson. Confirmou-se o diagnóstico do Cryptococcus deficiente de cápsula pela técnica de Fontana-Masson e pela imunofluorescência direta. É discutida a potencialidade das técnicas histoquímicas.

Bacteremias por Staphylococcus coagulase negativos oxacilina resistentes em um hospital escola na cidade de Santa Maria, Estado do Rio Grande do Sul

INTRODUÇÃO: Neste estudo, objetivou-se caracterizar a prevalência e o perfil de suscetibilidade de cepas de Staphylococcus coagulase negatives resistentes à oxacilina isoladas de culturas de sangue, em um hospital escola, localizado na Cidade de Santa Maria. Além disso, buscou-se comparar ao teste genotípico de referência, diferentes metodologias fenotípicas para a caracterização da resistência mediada pelo gene mecA. MÉTODOS: Após identificação (MicroScan® - Siemens), os isolados foram submetidos a testes de sensibilidade antimicrobiana a partir da difusão do disco e automação (MicroScan® - Siemens). A presença do gene mecA foi evidenciada através da técnica molecular de reação em cadeia da polimerase. RESULTADOS: A espécie prevalente foi Staphylococcus epidermidis (67%). O gene mecA foi detectado em 90% das cepas e conforme análise dos perfis de sensibilidade, observou-se um índice elevado de resistência a várias classes de antimicrobianos. Contudo, todos os isolados mostraram-se uniformemente sensíveis à vancomicina e tigeciclina. O disco de cefoxitina foi a metodologia fenotípica que melhor correlacionou-se com o padrão ouro. CONCLUSÕES: A análise da significância clínica de SCN isolados de hemoculturas e a detecção precisa da resistência à oxacilina representam fatores decisivos para a instituição correta da antibioticoterapia. Apesar da vancomicina constituir o tratamento usual na maioria dos hospitais brasileiros, tem a redução de seu emprego recomendada.

Evaluation of bacterial growth inhibition by mercaptopropionic acid in metallo-β-lactamase detection on multidrug-resistant Acinetobacter baumannii

INTRODUCTION: Metallo-β-lactamase (MBL) has been reported all over the world. METHODS: The inhibitory effect of mercaptopropionic acid (MPA) on bacterial growth was evaluated by comparison between disk diffusion and broth dilution methodology with determination of the minimum inhibitory concentration (MIC) for multidrug-resistant Acinetobacter baumanni strains. RESULTS: MPA significantly inhibited growth of the strains. CONCLUSIONS: The use of MPA can affect the results in phenotypic methods of MBL detection.

Contribuição ao estudo das Pasteurellas: pasteurella intermediária n. sp

Os autores decreveram uma nova bactéria - Pasteurella intermedia n. ap., obtida pela inoculação em cobaio de 2 cc. de sangue total de um indivíduo morto de bronco-pneumonia e suspeito de ter a forma grave de Tifo exantemático neotrópico. Têm a impressão que a Pasteurella marsupialis e a P. intermedia, constituem um grupo à parte, bem definido, dentro das Pasteurellas. Muito pequenas, de grande e persistente poder patogênico para os animais comuns de laboratório, mesmo quando as amostras das bactérias são conservadas pelos replantios em agar-comum, na temperatura e iluminação comum em laboratórios, durante anos. Estas duas Pasteurellas, ao contrário das demais, têm alto e inconfundível poder antígenico, para a formação de aglutininas e fixação do complemento e dão com constância uma "reação testicular" em cobaios machos, quando injetadas pela via intra-peritoneal, febre alta, esplenomegalia constante e às vezes notável, prestando-se à confusão para o diagnóstico diferencial e experimental com a raça VB do Tifo exantemático neotrófico no Brasil (Moléstia de Pisa, Gomes e Mayer).

Acerca del ciclo evolutivo del Trypanosoma (Schizotrypanum) cruzi Chagas 1909, en sus fases tisular y hematica

El autor pasa en revista los trabajos publicados sobre el ciclo evolutivo del Trypanosoma (S.) cruzi en el huésped vertebrado, desde el descubrimiento de la enfermedad hasta nuestros días. Luego analiza las ideas de los autores modernos, fundadas en gran parte en las observaciones que ya en 1914 realizaron MAYER y ROCHA LIMA de las cuales participan actualmente ROMAÑA y MEYER, ELKELES y WOOD. Finalmente expressa que a partir de los tripanosomas infectantes los parásitos que penetram en el protoplasma celular pueden seguir dos mecanismos en su evolución hacia cuerpos leishmanioides: 1.º) Por "regresión fusiforme" y 2.º) por "regresión orbicular"; llegados a la forma leishmanioide los parásitos se multiplican por división binaria, una vez lleno el protoplasma celular, siguen un processo inverso de transformación hacia tripanosoma que puede seguir igualmente dos mecanismos diversos: 1.) "progresión fusiforme" y 2.º) "progresión orbicular". Estos diversos mecanismos de transformación están esquematizados en la fig. N.º 1 del trabajo.

Plasmodium falciparum proteinases: cloning of the putative gene coding for the merozoite proteinase for erythrocyte invasion (MPEI) and determination of hydrolysis sites of spectrin by Pf37 proteinase

Numerous proteinase activities have been shown to be essential for the survival of Plasmodium falciparum. One approach to antimalarial chemotherapy, would be to block specifically one or several of these activities, by using compounds structurally analogous to the substrates of these proteinases. Such a strategy requires a detailed knowledge of the active site of the proteinase, in order to identify the best substrate for the proteinase. Aiming at developing such a strategy, two proteinases previously identified in our laboratory, were chosen for further characterization of their molecular structure and properties: the merozoite proteinase for erythrocytic invasion (MPEI), involved in the erythrocyte invasion by the merozoites, and the Pf37 proteinase, which hydrolyses human spectrin in vitro.

A Critical Review on Chagas Disease Chemotherapy

In this "Critical Review" we made a historical introduction of drugs assayed against Chagas disease beginning in 1912 with the works of Mayer and Rocha Lima up to the experimental use of nitrofurazone. In the beginning of the 70s, nifurtimox and benznidazole were introduced for clinical treatment, but results showed a great variability and there is still a controversy about their use for chronic cases. After the introduction of these nitroheterocycles only a few compounds were assayed in chagasic patients. The great advances in vector control in the South Cone countries, and the demonstration of parasite in chronic patients indicated the urgency to discuss the etiologic treatment during this phase, reinforcing the need to find drugs with more efficacy and less toxicity. We also review potential targets in the parasite and present a survey about new classes of synthetic and natural compounds studied after 1992/1993, with which we intend to give to the reader a general view about experimental studies in the area of the chemotherapy of Chagas disease, complementing the previous papers of Brener (1979) and De Castro (1993).

Pre-mRNA trans-splicing: from kinetoplastids to mammals, an easy language for life diversity

Since the discovery that genes are split into intron and exons, the studies of the mechanisms involved in splicing pointed to presence of consensus signals in an attempt to generalize the process for all living cells. However, as discussed in the present review, splicing is a theme full of variations. The trans-splicing of pre-mRNAs, the joining of exons from distinct transcripts, is one of these variations with broad distribution in the phylogenetic tree. The biological meaning of this phenomenon is discussed encompassing reactions resembling a possible noise to mechanisms of gene expression regulation. All of them however, can contribute to the generation of life diversity.

RNA polymerase I promoter and splice acceptor site recognition affect gene expression in non-pathogenic Leishmania species

Leishmania (Sauroleishmania) tarentolae has biotechnological potential for use as live vaccine against visceral leishmaniasis and as a system for the over expression of eukaryotic proteins that possess accurate post-translational modifications. For both purposes, new systems for protein expression in this non-pathogenic protozoan are necessary. The ribosomal RNA promoter proved to be a stronger transcription driver since its use yielded increased levels of recombinant protein in organisms of both genera Trypanosoma or Leishmania. We have evaluated heterologous expression systems using vectors with two different polypyrimidine tracts in the splice acceptor site by measuring a reporter gene transcribed from L. tarentolae RNA polymerase I promoter. Our data indicate that the efficiency of chloramphenicol acetyl transferase expression changed drastically with homologous or heterologous sequences, depending on the polypyrimidine tract used in the construct and differences in size and/or distance from the AG dinucleotide. In relation to the promoter sequence the reporter expression was higher in heterologous lizard-infecting species than in the homologous L. tarentolae or in the mammalian-infecting L. (Leishmania) amazonensis.

Present situation and new strategies for Chagas disease chemotherapy: a proposal

Treatments for Chagas disease have been administered since the first attempts by Mayer & Rocha Lima (1912, 1914) and up to the drugs currently in use (nifurtimox and benznidazole), along with potential drugs such as allopurinol and first, second and third-generation antifungal agents (imidazoles and triazoles), in separate form. Several diseases such as tuberculosis, leprosy and AIDS only came under control after they were treated with associations of drugs with different mechanisms of action. This not only boosts the action of the different compounds, but also may avoid the development of parasite resistance .To this end, over the short term, we propose experimental studies on laboratory animals and clinical trials with the following associations: (i) nifurtimox (8 mg/kg/day) + benznidazole (5 mg/kg/day) x 60 consecutive days; (ii) nifurtimox (8 mg/kg/day) or benznidazole (5 mg/kg/day) + allopurinol (8-10 mg/kg/day) x 60 days and (iii) nifurtimox (8 mg/kg/day) or benznidazole (5 mg/kg/day) + ketoconazole, fluconazole or itraconazole (5-6 mg/kg/day) x 60 consecutive days. The doses of the drugs and the treatment schedules for the clinical trials must be adapted according to the side effects. From these, other double or triple associations could be made, using drugs with different mechanisms of action. This proposal does not exclude investigations on new drugs over the median and long terms, targeting other aspects of the metabolism of Trypanosoma cruzi. Until such time as the ideal drug for specific treatment of Chagas disease might be discovered, we need to develop new strategies for achieving greater efficacy with the old drugs in associations and to develop rational experimentation with new drugs.

Footprints of a trypanosomatid RNA world: pre-small subunit rRNA processing by spliced leader addition trans-splicing

The addition of a capped mini-exon [spliced leader (SL)] through trans-splicing is essential for the maturation of RNA polymerase (pol) II-transcribed polycistronic pre-mRNAs in all members of the Trypanosomatidae family. This process is an inter-molecular splicing reaction that follows the same basic rules of cis-splicing reactions. In this study, we demonstrated that mini-exons were added to precursor ribosomal RNA (pre-rRNA) are transcribed by RNA pol I, including the 5' external transcribed spacer (ETS) region. Additionally, we detected the SL-5'ETS molecule using three distinct methods and located the acceptor site between two known 5'ETS rRNA processing sites (A' and A1) in four different trypanosomatids. Moreover, we detected a polyadenylated 5'ETS upstream of the trans-splicing acceptor site, which also occurs in pre-mRNA trans-splicing. After treatment with an indirect trans-splicing inhibitor (sinefungin), we observed SL-5'ETS decay. However, treatment with 5-fluorouracil (a precursor of RNA synthesis that inhibits the degradation of pre-rRNA) led to the accumulation of SL-5'ETS, suggesting that the molecule may play a role in rRNA degradation. The detection of trans-splicing in these molecules may indicate broad RNA-joining properties, regardless of the polymerase used for transcription.

Identification of SL addition trans-splicing acceptor sites in the internal transcribed spacer I region of pre-rRNA in Leishmania (Leishmania) amazonensis

Trypanosomatidae is a family of early branching eukaryotes harbouring a distinctive repertoire of gene expression strategies. Functional mature messenger RNA is generated via the trans-splicing and polyadenylation processing of constitutively transcribed polycistronic units. Recently, trans-splicing of pre-small subunit ribosomal RNA in the 5' external transcribed spacer region and of precursor tRNAsec have been described. Here, we used a previously validated semi-nested reverse transcription-polymerase chain reaction strategy to investigate internal transcribed spacer (ITS) I acceptor sites in total RNA from Leishmania (Leishmania) amazonensis. Two distinct spliced leader-containing RNAs were detected indicating that trans-splicing reactions occur at two AG acceptor sites mapped in this ITS region. These data provide further evidence of the wide spectrum of RNA molecules that act as trans-splicing acceptors in trypanosomatids.

Complete genome sequence of Deltapapillomavirus 4 (bovine papillomavirus 2) from a bovine papillomavirus lesion in Amazon Region, Brazil

The complete genome sequence of bovine papillomavirus 2 (BPV2) from Brazilian Amazon Region was determined using multiple-primed rolling circle amplification followed by Illumina sequencing. The genome is 7,947 bp long, with 45.9% GC content. It encodes seven early (E1, E2,E4, E5, E6,E7, and E8) and two late (L1 and L2) genes. The complete genome of a BPV2 can help in future studies since this BPV type is highly reported worldwide although the lack of complete genome sequences available.

Perceptions of unfairness in price increases: an experimental study

This experimental study investigates antecedents and consequences of perceptions of price unfairness in a price increase situation. The proposed theoretical model states that consumer dependence on the service provider as well as the relevance the consumer attributes to the service (for the consumer's life) will affect his/her degree of (a) unfairness price perception, (b) anger, and (c) intention to complain and retaliate. The results support all the hypotheses specified in the model. The findings not only indicate that some situations of unfairness price perception lead to stronger emotions and more dramatic reactions from consumers, but also allow us to predict which situations of perceived unfairness offer greater risks and have greater potential for conflict.