ABSTRACT
Cryptococcosis is one of the most common opportunistic fungal infections in patients with acquired immunodeficiency syndrome (AIDS). We report 13 cases of cryptococcal infection based on histopathology, serology and cultures. Epidemiological analysis, histochemical techniques of hematoxilin and eosin (HE) and Grocot's silver (GMS), as well special histochemical techniques such as Mayer's mucicarmine (MM) and Fontana-Masson (FM), cryptococcal antigen test (CrAg) and isolation on fungal media: Sabouraud's (SAB), brain-heart infusion agar (BHI) and canavanine-glycine-bromothymol blue (CGB) agar were analyzed. Unsatisfactory staining results by MM stain associated to negative titers by CrAg test, which FM stain confirmed that capsule-deficient Cryptococcus infections were observed in four cases. Eight isolated cases were identified as follows: six cases were infection with Cryptococcus neoformans and two cases were Cryptococcus gattii.
A criptococose é a mais comum infecção fúngica oportunística observada em pacientes com síndrome da imunodeficiência adquirida (AIDS). Relatamos 13 casos da infecção baseados no diagnóstico histopatológico, sorológico e cultivo. Foram analisadas: a epidemiologia, as técnicas histoquímicas básicas de hematoxilina-eosina (HE) e coloração pela prata (GMS), bem como as técnicas histoquímicas especiais de mucicarmim de Mayer (MM) e Fontana-Masson (FM), o teste do antígeno criptocóccico (CrAg) e o isolamento em cultivos em ágar-Sabouraud (SAB), ágar infusão de cérebro-coração (BHI) e meio com canavanina azul de bromotimol (CGB). Em quatro casos, resultados tintoriais insatisfatórios pela coloração de MM associados a títulos negativos pelo teste do CrAg, a coloração de FM confirmou a infecção pelo Cryptococcus deficiente de cápsula. Oito isolados foram identificados: seis casos apresentaram a infecção por Cryptococcus neoformans e dois casos apresentaram a infecção por Cryptococcus gattii.
Subject(s)
Adolescent , Adult , Child , Female , Humans , Male , Middle Aged , Young Adult , Cryptococcosis/diagnosis , Cryptococcus/isolation & purification , Biopsy , Coloring Agents , Cryptococcosis/microbiology , Cryptococcosis/pathology , Cryptococcus/classification , Histocytochemistry , Immunocompromised Host , Retrospective Studies , Staining and Labeling , Young AdultABSTRACT
Ribonucleotide reductase (RNR) of the yeast Saccharomyces cerevisiae is a tetrameric protein complex, consisting of two large and two small subunits. The small subunits Y2 and Y4 form a heterodimer and are encoded by yeast genes RNR2 and RNR4, respectively. Loss of Y4 in yeast mutant rnr4delta can be compensated for by up-regulated expression of Y2, and the formation of a small subunit Y2Y2 homodimer that allows for a partially functional RNR. However, rnr4delta mutants exhibit slower growth than wild-type (WT) cells and are sensitive to many mutagens, amongst them UVC and photo-activated mono- and bi-functional psoralens. Cells of the haploid rnr4delta mutant also show a 3- to 4-fold higher sensitivity to the oxidative stress-inducing chemical stannous chloride than those of the isogenic WT. Both strains acquired increased resistance to SnCl2 with age of culture, i.e., 24-h cultures were more sensitive than cells grown for 2, 3, 4, and 5 days in liquid culture. However, the sensitivity factor of three to four (WT/mutant) did not change significantly. Cultures of the rnr4delta mutant in stationary phase of growth always showed higher frequency of budding cells (budding index around 0.5) than those of the corresponding WT (budding index <0.1), pointing to a delay of mitosis/cytokinesis.