Morbidity after thoracoscopic resection of congenital pulmonary airway malformations (CPAM): single center experience over a decade.

PURPOSE: Video-assisted thoracoscopic (VATS) resection of CPAM in children is an established, albeit controversial strategy for its management. We report a 10-year single center experience. METHODS: All children underwent VATS (2008-2017) and their current status was reviewed. Patients were grouped: 'symptomatic-P' (if parents reported recurrent lower respiratory tract infections etc.) or 'symptomatic-S' (neonates presenting with respiratory distress/difficulty) or 'asymptomatic'. RESULTS: 73 children, aged 10 m (4d-14yrs) underwent VATS; a neonate as an emergency ('symptomatic-S') and all others electively. The lesion was unilateral in all but one case. Histologically none were malignant. Of the elective 72 cases, 7 (10%) required conversion to open thoracotomy. Twenty (27.7%) were 'symptomatic-P' and the duration of surgery when compared to 'asymptomatic' children was longer 269 (range 129-689) versus 178 (range 69-575) minutes (P = 0.01). Post operatively, 8 children (11%) had a grade III/IV (Clavien-Dindo) complication; persistent air leak/pneumothorax (n = 5), chylothorax (n = 1), pleural effusion (n = 1) and seizure/middle cerebral artery thrombosis (n = 1). There was no mortality. Twenty-four children (33.3%) were reported 'symptomatic-P' post-surgery after a median follow up of 2.18 years. The surgical intervention had no impact on 'symptomatic-P' status (P = 0.46). CONCLUSION: The risks of surgery may outweigh benefit in asymptomatic children. CLINICALTRIALS. GOV IDENTIFIER: NCT04449614.

Analysis of simple sequence repeat (SSR) structure and sequence within Epichloë endophyte genomes reveals impacts on gene structure and insights into ancestral hybridization events.

Epichloë grass endophytes comprise a group of filamentous fungi of both sexual and asexual species. Known for the beneficial characteristics they endow upon their grass hosts, the identification of these endophyte species has been of great interest agronomically and scientifically. The use of simple sequence repeat loci and the variation in repeat elements has been used to rapidly identify endophyte species and strains, however, little is known of how the structure of repeat elements changes between species and strains, and where these repeat elements are located in the fungal genome. We report on an in-depth analysis of the structure and genomic location of the simple sequence repeat locus B10, commonly used for Epichloë endophyte species identification. The B10 repeat was found to be located within an exon of a putative bZIP transcription factor, suggesting possible impacts on polypeptide sequence and thus protein function. Analysis of this repeat in the asexual endophyte hybrid Epichloë uncinata revealed that the structure of B10 alleles reflects the ancestral species that hybridized to give rise to this species. Understanding the structure and sequence of these simple sequence repeats provides a useful set of tools for readily distinguishing strains and for gaining insights into the ancestral species that have undergone hybridization events.

Role of ferric reductases in iron acquisition and virulence in the fungal pathogen Cryptococcus neoformans.

Iron acquisition is critical for the ability of the pathogenic yeast Cryptococcus neoformans to cause disease in vertebrate hosts. In particular, iron overload exacerbates cryptococcal disease in an animal model, defects in iron acquisition attenuate virulence, and iron availability influences the expression of major virulence factors. C. neoformans acquires iron by multiple mechanisms, including a ferroxidase-permease high-affinity system, siderophore uptake, and utilization of both heme and transferrin. In this study, we examined the expression of eight candidate ferric reductase genes and their contributions to iron acquisition as well as to ferric and cupric reductase activities. We found that loss of the FRE4 gene resulted in a defect in production of the virulence factor melanin and increased susceptibility to azole antifungal drugs. In addition, the FRE2 gene was important for growth on the iron sources heme and transferrin, which are relevant for proliferation in the host. Fre2 may participate with the ferroxidase Cfo1 of the high-affinity uptake system for growth on heme, because a mutant lacking both genes showed a more pronounced growth defect than the fre2 single mutant. A role for Fre2 in iron acquisition is consistent with the attenuation of virulence observed for the fre2 mutant. This mutant also was defective in accumulation in the brains of infected mice, a phenotype previously observed for mutants with defects in high-affinity iron uptake (e.g., the cfo1 mutant). Overall, this study provides a more detailed view of the iron acquisition components required for C. neoformans to cause cryptococcosis.

Expanding fungal pathogenesis: Cryptococcus breaks out of the opportunistic box.

Cryptococcus neoformans is generally considered to be an opportunistic fungal pathogen because of its tendency to infect immunocompromised individuals, particularly those infected with HIV. However, this view has been challenged by the recent discovery of specialized interactions between the fungus and its mammalian hosts, and by the emergence of the related species Cryptococcus gattii as a primary pathogen of immunocompetent populations. In this Review, we highlight features of cryptococcal pathogens that reveal their adaptation to the mammalian environment. These features include not only remarkably sophisticated interactions with phagocytic cells to promote intracellular survival, dissemination to the central nervous system and escape, but also surprising morphological and genomic adaptations such as the formation of polyploid giant cells in the lung.

HapX positively and negatively regulates the transcriptional response to iron deprivation in Cryptococcus neoformans.

The fungal pathogen Cryptococcus neoformans is a major cause of illness in immunocompromised individuals such as AIDS patients. The ability of the fungus to acquire nutrients during proliferation in host tissue and the ability to elaborate a polysaccharide capsule are critical determinants of disease outcome. We previously showed that the GATA factor, Cir1, is a major regulator both of the iron uptake functions needed for growth in host tissue and the key virulence factors such as capsule, melanin and growth at 37°C. We are interested in further defining the mechanisms of iron acquisition from inorganic and host-derived iron sources with the goal of understanding the nutritional adaptation of C. neoformans to the host environment. In this study, we investigated the roles of the HAP3 and HAPX genes in iron utilization and virulence. As in other fungi, the C. neoformans Hap proteins negatively influence the expression of genes encoding respiratory and TCA cycle functions under low-iron conditions. However, we also found that HapX plays both positive and negative roles in the regulation of gene expression, including a positive regulatory role in siderophore transporter expression. In addition, HapX also positively regulated the expression of the CIR1 transcript. This situation is in contrast to the negative regulation by HapX of genes encoding GATA iron regulatory factors in Aspergillus nidulans and Schizosaccharomyces pombe. Although both hapX and hap3 mutants were defective in heme utilization in culture, only HapX made a contribution to virulence, and loss of HapX in a strain lacking the high-affinity iron uptake system did not cause further attenuation of disease. Therefore, HapX appears to have a minimal role during infection of mammalian hosts and instead may be an important regulator of environmental iron uptake functions. Overall, these results indicated that C. neoformans employs multiple strategies for iron acquisition during infection.