Ketoconazole in Paracoccidioidomycosis: Efficacy of prolonged oral therapy

Summary Ketoconazole, a new oral imidazole derivative, was employed for the treatment of five patients with paracoccidioidomycosis. The response was excellent, with objective clinical improvement and healing of both mucocutaneous and pulmonary lesions. Mycological and serological tests, as well as delayed hypersensitivity, were assessed and found to correlate with clinical improvement. Therapy was conducted for 12 months with a dose of 200 mg day in 2 patients; in the remainder the dose was reduced (100 mg day) after the first 6 months and maintained as such for an equal period. No side-effects or toxicity were noted despite prolonged treatment. The advantages of the new therapeutic approach are discussed.

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Sumario Un nuevo derivado del imidazole para uso oral, ketoconazole, fué empleado en el tratamiento de 5 pacientes con paracoccidioidomicosis. Se condujo la terapia por un año, con base a la administración de una pastilla (200 mg) por día en 2 pacientes; en los 3 restantes, esta dosis fué reducida a la mitad y mantenida en tal nivel por otros 6 meses. La respuesta fué excelente con mejoría clínica objetiva y cicatrización de las lesiones tegumentarias y pulmonares. Los estudios micológicos y serológicos, a la par que la sensibilidad cutanea, llevados a cabo durante el curso del tratamiento indicaron también mejoría. No se anotó ninguna toxicidad para la droga ni los pacientes experimentaron efectos secundarios. Las ventajas de esta nueva clase de terapia son discutidas en el texto.

     

Inability of Escherichia coli to resuscitate from the viable but nonculturable state

After induction of the viable but nonculturable (VBNC) state in Escherichia coli populations, we analysed abiotic and biotic factors suggested to promote the resuscitation process. The response to the stressing conditions implied the formation of three subpopulations, culturable, VBNC and nonviable. In most adverse situations studied, the VBNC subpopulation did not represent the dominant fraction, decreasing with time. This suggests that, in most cases, the VBNC is not a successful phenotype. Combining methods of dilution and inhibition of remaining culturable cells, we designed a working protocol in order to distinguish unequivocally between regrowth and resuscitation. Reversion of abiotic factors inducing nonculturability as well as prevention of additional oxidative stress did not provoke resuscitation. Participation of biotic factors was studied by addition of supernatants from different origin without positive results. These results indicate that the E. coli strain used is not able to resuscitate from the VBNC state. VBNC cells release into the surrounding medium, and could thus aid in the survival of persisting culturable cells. The formation of a VBNC subpopulation could thus be considered as an adaptive process, designed for the benefit of the population as a whole.     

DNA microdevice for electrochemical detection of Escherichia coli 0157:H7 molecular markers

An electrochemical DNA sensor based on the hybridization recognition of a single-stranded DNA (ssDNA) probe immobilized onto a gold electrode to its complementary ssDNA is presented. The DNA probe is bound on gold surface electrode by using self-assembled monolayer (SAM) technology. An optimized mixed SAM with a blocking molecule preventing the nonspecific adsorption on the electrode surface has been prepared. In this paper, a DNA biosensor is designed by means of the immobilization of a single stranded DNA probe on an electrochemical transducer surface to recognize specifically Escherichia coli (E. coli) 0157:H7 complementary target DNA sequence via cyclic voltammetry experiments. The 21 mer DNA probe including a C6 alkanethiol group at the 5' phosphate end has been synthesized to form the SAM onto the gold surface through the gold sulfur bond. The goal of this paper has been to design, characterise and optimise an electrochemical DNA sensor. In order to investigate the oligonucleotide probe immobilization and the hybridization detection, experiments with different concentration of DNA and mismatch sequences have been performed. This microdevice has demonstrated the suitability of oligonucleotide Self-assembled monolayers (SAMs) on gold as immobilization method. The DNA probes deposited on gold surface have been functional and able to detect changes in bases sequence in a 21-mer oligonucleotide.     

MAP kinase pathways as regulators of fungal virulence

MAP kinases are dual phosphorylated protein kinases, present in eukaryotes, which mediate differentiation programs and immune responses in mammalian cells. In pathogenic fungi, MAP kinases are key elements that control adaptation to environmental stress. Recent studies have shown that these pathways have an essential role in the control of essential virulence factors such as capsule biogenesis in Cryptococcus neoformans or morphogenesis, invasion and oxidative stress in Candida albicans. Although MAP kinases sense different activating signals, there is a considerable degree of crosstalk and/or overlap, which enables them to integrate, amplify and modulate the appropriate protective and adaptive response. MAP kinases behave as a 'functional nervous system' that controls virulence and influences the progression of the disease.     

Quantitative Trait Loci Controlling Vegetative Growth Rate in the Edible Basidiomycete Pleurotus ostreatus

Mycelium growth rate is a quantitative characteristic that exhibits continuous variation. This trait has applied interest, as growth rate is correlated with production yield and increased advantage against competitors. In this work, we studied growth rate variation in the edible basidiomycete Pleurotus ostreatus growing as monokaryotic or dikaryotic mycelium on Eger medium or on wheat straw. Our analysis resulted in identification of several genomic regions (quantitative trait loci [QTLs]) involved in the control of growth rate that can be mapped on the genetic linkage map of this fungus. In some cases monokaryotic and dikaryotic QTLs clustered at the same map position, indicating that there are principal genomic areas responsible for growth rate control. The availability of this linkage map of growth rate QTLs can help in the design of rational strain breeding programs based on genomic information.     

Microrheological characteristics of reticulocyte in vivo

Using the method of phenylhydrazine-induced anemia in rabbits, a mass of new reticu-locytes, which synchronously grow, were got in vivo. The measurements of deformation index, orientation index, electrophoresis mobility etc. were performed for more than 72 h in the process of reticulocytes turning into red blood cells in vivo. There were obvious changes in the micro-rheological characteristics of reticulocytes in the course of turning into erythrocytes. The present study is significant in clinic for studying erythrocytes' microrheological characteristics when there are a lot of reticulocytes in blood, and also important in basic theorem for studying reticulocytes microrheological characteristics. It makes up a deficiency in the study on microrheological characteristics of reticulocytes turning into new RBCs from reticulocytes during reticulocytes life span.     

The effects of selective breeding against scrapie susceptibility on the genetic variability of the Latxa Black-Faced sheep breed

Breeding sheep populations for scrapie resistance could result in a loss of genetic variability. In this study, the effect on genetic variability of selection for increasing the ARR allele frequency was estimated in the Latxa breed. Two sources of information were used, pedigree and genetic polymorphisms (fifteen microsatellites). The results based on the genealogical information were conditioned by a low pedigree completeness level that revealed the interest of also using the information provided by the molecular markers. The overall results suggest that no great negative effect on genetic variability can be expected in the short time in the population analysed by selection of only ARR/ARR males. The estimated average relationship of ARR/ARR males with reproductive females was similar to that of all available males whatever its genotype: 0.010 vs. 0.012 for a genealogical relationship and 0.257 vs. 0.296 for molecular coancestry, respectively. However, selection of only ARR/ARR males implied important losses in founder animals (87 percent) and low frequency alleles (30 percent) in the ram population. The evaluation of mild selection strategies against scrapie susceptibility based on the use of some ARR heterozygous males was difficult because the genetic relationships estimated among animals differed when pedigree or molecular information was used, and the use of more molecular markers should be evaluated.     

Comparison of short-term toxicity between Nano-Se and selenite in mice

We previously reported that, as compared with selenite, nano red elemental selenium (Nano-Se) had lower acute toxicity in mice and similar bioavailability in terms of up-regulating seleno-enzymes. The short-term toxicity of both selenite and Nano-Se in mice was further compared in this study. At an oral dose of 6 mg/kg bw per day administered for consecutive 12 days, selenite and Nano-Se completely and partially suppressed mice growth respectively. Abnormal liver function was more pronounced with selenite treatment than Nano-Se as indicated by the increase of both alanine aminotransferase and aspartate aminotransferase in serum. Selenite inhibited liver catalase and superoxide dismutase activities, whereas, Nano-Se did not affect these two antioxidant enzymes. Selenite increased the malondialdehyde content of liver, but Nano-Se decreased it. Both Se forms had similar effects on depletion of reduced glutathione and up-regulated glutathione peroxidase. Nano-Se was more potent than selenite in the induction of glutathione S-transferase. At oral doses of 2 or 4 mg/kg bw per day for consecutive 15 days, selenite was more active than Nano-Se in supressing growth, deleting reduced glutathione, and inhibiting superoxide dismutase activities. Taken together, these results indicate that over a short-term, a high-dose of selenite caused more pronounced oxidative stress, greater liver injury, and prominent retardation of growth as compared to Nano-Se.