La infección fúngica en el paciente pediátrico inmunodeprimido

In recent years, immunodeficiency condition has experienced a rise among children, who are at risk of invasive fungal infections (IFI) due to their health condition. Cancer, non-malignant hematological diseases, as primary immunodeficiencies, hematopoietic stem cell transplantation (HSCT), extreme prematurity, or critically ill condition in Pediatric Intensive Care Unit (PICU) are some immunosuppressive situations in children. The use of oncologic therapies, including immunotherapy and monoclonal antibodies, for the treatment of the aforementioned health conditions has led to an increase in morbidity and mortality rates of IFI in children.The underlying diseases and their management, comorbidities, the diagnostic tests used (both molecular and imaging), as well as the treatment used can be significantly different between adult patients and children admitted to PICU or with cancer. In pediatrics, the treatment of IFI is based primarily on pharmacokinetic studies performed in adults. In higher risk patients prophylaxis should be considered and, in the case of an IFI diagnosis, an antifungal treatment should be administered as early as possible, supported by the reversion of the immune dysfunction and surgery when appropriate.     

Multigenerational experimental simulation of climate change on an economically important insect pest

Long‐term multigenerational experimental simulations of climate change on insect pests of economically and socially important crops are crucial to anticipate challenges for feeding humanity in the not‐so‐far future. Mexican bean weevil Zabrotes subfasciatus, is a worldwide pest that attacks the common bean Phaseolus vulgaris seeds, in crops and storage. We designed a long term (i.e., over 10 generations), experimental simulation of climate change by increasing temperature and CO₂ air concentration in controlled conditions according to model predictions for 2100. Higher temperature and CO₂ concentrations favored pest''s egg‐to‐adult development survival, even at high female fecundity. It also induced a reduction of fat storage and increase of protein content but did not alter body size. After 10 generations of simulation, genetic adaptation was detected for total lipid content only, however, other traits showed signs of such process. Future experimental designs and methods similar to ours, are key for studying long‐term effects of climate change through multigenerational experimental designs.     

Current status of the organ replacement approach for malignancies and an overture for organ bioengineering and regenerative medicine

Significant achievements in the organ replacement approach for malignancies over the last 2 decades opened new horizons, and the age of “Transplant Oncology” has dawned. The indications of liver transplantation for malignancies have been carefully expanded by a strict patient selection to assure comparable outcomes with non-malignant diseases. Currently, the Milan criteria, gold standard for hepatocellular carcinoma, are being challenged by high-volume centers worldwide. Neoadjuvant chemoradiation therapy and liver transplantation for unresectable hilar cholangiocarcinoma has been successful in specialized institutions. For other primary and metastatic liver tumors, clinical evidence to establish standardized criteria is lacking. Intestinal and multivisceral transplantation is an option for low-grade neoplasms deemed unresectable by conventional surgery. However, the procedure itself is in the adolescent stage. Solid organ transplantation for malignancies inevitably suffers from “triple distress,” i.e., oncological, immunological, and technical. Organ bioengineering and regenerative medicine should serve as the “triple threat” therapy and revolutionize “Transplant Oncology.”     

Manganese superoxide dismutase in disease

Manganese superoxide dismutase (MnSOD) is essential for life as dramatically illustrated by the neonatal lethality of mice that are deficient in MnSOD. In addition, mice expressing only 50% of the normal compliment of MnSOD demonstrate increased susceptibility to oxidative stress and severe mitochondrial dysfunction resulting from elevation of reactive oxygen species. Thus, it is important to know the status of both MnSOD protein levels and activity in order to assess its role as an important regulator of cell biology.

Numerous studies have shown that MnSOD can be induced to protect against pro-oxidant insults resulting from cytokine treatment, ultraviolet light, irradiation, certain tumors, amyotrophic lateral sclerosis, and ischemia/reperfusion. In addition, overexpression of MnSOD has been shown to protect against pro-apoptotic stimuli as well as ischemic damage. Conversely, several studies have reported declines in MnSOD activity during diseases including cancer, aging, progeria, asthma, and transplant rejection. The precise biochemical/molecular mechanisms involved with this loss in activity are not well understood. Certainly, MnSOD gene expression or other defects could play a role in such inactivation. However, based on recent findings regarding the susceptibility of MnSOD to oxidative inactivation, it is equally likely that post-translational modification of MnSOD may account for the loss of activity. Our laboratory has recently demonstrated that MnSOD is tyrosine nitrated and inactivated during human kidney allograft rejection and human pancreatic ductal adenocarcinoma. We have determined that peroxynitrite (ONOO^-) is the only known biological oxidant competent to inactivate enzymatic activity, to nitrate critical tyrosine residues, and to induce dityrosine formation in MnSOD. Tyrosine nitration and inactivation of MnSOD would lead to increased levels of superoxide and concomitant increases in ONOO^- within the mitochondria which, could lead to tyrosine nitration/oxidation of key mitochondrial proteins and ultimately mitochondrial dysfunction and cell death. This article assesses the important role of MnSOD activity in various pathological states in light of this potentially lethal positive feedback cycle involving oxidative inactivation.     

X-ray microtomography for imaging of developing spiders inside egg cocoons

Embryogenesis is especially sensitive to external factors. The changes in its course are often used as biomarkers of environmental impact. Since spider embryogenesis takes place inside cocoons, it is crucial to find a reliable tool to analyze this developmental phase with no intrusion into the cocoons. The aim of this study was to verify the efficacy of X-ray microtomography for non-invasive analysis of embryonic morphology and egg quantity in the cocoons of Xerolycosa nemoralis and Agelena labyrinthica from polluted and reference sites. X-ray microtomography slice images as well as 3D images and animations obtained from digital visualization of those slides were used to study the morphology of embryos and egg arrangement in the cocoons. Any disorders in embryogenesis or malformation of embryos in relation to site of origin have not been found, but inside an egg cocoon of X. nemoralis from the polluted site embryos differing form each other by one developmental stage were identified. Egg calculation revealed a K- reproductive strategy of X. nemoralis from polluted sites. Finally, future prospects and benefits, and weaknessess of this method for the study of spider cocoons have presented.     

A comparison of two autoradiographic methods for detecting radiolabeled nucleic acids in embryos.

Two methods for preparing embryos for autoradiographic study of newly synthesized nucleic acids are described and compared. The first method consists of rapidly fixing radiolabeled embryos with acetic acid:methanol, spreading them on glass slides and exposing them for 8 days with a photographic emulsion. The second method consists of fixing, embedding in resin, and sectioning the embryos before their exposure with the emulsion for 3 weeks. Both techniques have many applications in studies of early embryonic activity, but the spread technique is very sensitive, simpler, and faster.     

Fatal SV40‐associated pneumonia and nephropathy following renal allotransplantation in rhesus macaque

Recrudescence of latent and dormant viruses may lead to overwhelming viremia in immunosuppressed hosts. In immunocompromised hosts, Simian virus 40 (SV40) reactivation is known to cause nephritis and demyelinating central nervous system disease. Here, we report SV40 viremia leading to fatal interstitial pneumonia in an immunosuppressed host following renal allotransplantation.     

Trait differentiation and adaptation of plants along elevation gradients

Studies of genetic adaptation in plant populations along elevation gradients in mountains have a long history, but there has until now been neither a synthesis of how frequently plant populations exhibit adaptation to elevation nor an evaluation of how consistent underlying trait differences across species are. We reviewed studies of adaptation along elevation gradients (i) from a meta‐analysis of phenotypic differentiation of three traits (height, biomass and phenology) from plants growing in 70 common garden experiments; (ii) by testing elevation adaptation using three fitness proxies (survival, reproductive output and biomass) from 14 reciprocal transplant experiments; (iii) by qualitatively assessing information at the molecular level, from 10 genomewide surveys and candidate gene approaches. We found that plants originating from high elevations were generally shorter and produced less biomass, but phenology did not vary consistently. We found significant evidence for elevation adaptation in terms of survival and biomass, but not for reproductive output. Variation in phenotypic and fitness responses to elevation across species was not related to life history traits or to environmental conditions. Molecular studies, which have focussed mainly on loci related to plant physiology and phenology, also provide evidence for adaptation along elevation gradients. Together, these studies indicate that genetically based trait differentiation and adaptation to elevation are widespread in plants. We conclude that a better understanding of the mechanisms underlying adaptation, not only to elevation but also to environmental change, will require more studies combining the ecological and molecular approaches.