Keratoacanthoma and Cutaneous Squamous Cell Carcinoma With PD-1 and PD-L1 Inhibitor Use.

This cross-sectional study assesses risk of dermatological immune-related adverse events associated with immunotherapy for cancer.

Range-wide persistence of the endangered arroyo toad (Anaxyrus californicus) for 20+ years following a prolonged drought.

Prolonged drought due to climate change has negatively impacted amphibians in southern California, U.S.A. Due to the severity and length of the current drought, agencies and researchers had growing concern for the persistence of the arroyo toad (Anaxyrus californicus), an endangered endemic amphibian in this region. Range-wide surveys for this species had not been conducted for at least 20 years. In 2017-2020, we conducted collaborative surveys for arroyo toads at historical locations. We surveyed 88 of the 115 total sites having historical records and confirmed that the arroyo toad is currently extant in at least 61 of 88 sites and 20 of 25 historically occupied watersheds. We did not detect toads at almost a third of the surveyed sites but did detect toads at 18 of 19 specific sites delineated in the 1999 Recovery Plan to meet one of four downlisting criteria. Arroyo toads are estimated to live 7-8 years, making populations susceptible to prolonged drought. Drought is estimated to increase in frequency and duration with climate change. Mitigation strategies for drought impacts, invasive aquatic species, altered flow regimes, and other anthropogenic effects could be the most beneficial strategies for toad conservation and may also provide simultaneous benefits to several other native species that share the same habitat.

A case of vancomycin-induced drug rash with eosinophilia and systemic symptoms (DRESS) syndrome with failure to respond to cyclosporine treatment.

Drug rash with eosinophilia and systemic symptoms (DRESS) is a rare delayed drug reaction that often occurs 2-6 weeks after initiation of therapy and may develop into a life-threatening systemic reaction. Besides immediate discontinuation of the suspected inciting drug, initiation of high dose systemic corticosteroids has long been the mainstay of treatment for severe cases. Nevertheless, significant drawbacks associated with systemic corticosteroid therapy, such as the requirement of a long tapering period post resolution and extensive adverse side effects profile, have motivated clinicians to seek alternative treatment options. Over the past decade, an undisputed increasing number of favorable case reports has highlighted cyclosporine as an emerging, safe, and effective alternative despite inconsistent dosing regimens reported. Herein, we report a severe case of vancomycin-induced DRESS syndrome in which the patient failed initial intervention with cyclosporine and needed rescue with methylprednisolone. To the best of our knowledge, this constitutes the first unsuccessful report of cyclosporine treatment for DRESS syndrome.

Improvement in exercise duration, lung function and well-being in G551D-cystic fibrosis patients: a double-blind, placebo-controlled, randomized, cross-over study with ivacaftor treatment.

G551D, a mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, results in impaired chloride channel function in cystic fibrosis (CF) with multiple end-organ manifestations. The effect of ivacaftor, a CFTR-potentiator, on exercise capacity in CF is unknown. Twenty G551D-CF patients were recruited to a single-centre, double-blind, placebo-controlled, 28-day crossover study of ivacaftor. Variables measured included percentage change from baseline (%Δ) of VO2max (maximal oxygen consumption, primary outcome) during cardiopulmonary exercise testing (CPET), relevant other CPET physiological variables, lung function, body mass index (BMI), sweat chloride and disease-specific health related quality of life (QOL) measures (CFQ-R and Alfred Wellness (AWEscore)). %ΔVO2max was unchanged compared with placebo as was %Δminute ventilation. However, %Δexercise time (mean 7.3, CI 0.5-14,1, P=0.0222) significantly increased as did %ΔFEV1 (11.7%, range 5.3-18.1, P<0·005) and %ΔBMI (1.2%, range 0.1-2.3, P=0·0393) whereas sweat chloride decreased (mean -43.4; range -55.5-18.1 mmol·l-1, P<0·005). Total and activity based domains in both CFQ-R and AWEscore also increased. A positive treatment effect on spirometry, BMI (increased), SCT (decreased) and total and activity based CF-specific QOL measures was expected. However, the lack of discernible improvement in VO2max and VE despite other positive changes including spirometric lung function and exercise time with a 28-day ivacaftor intervention suggests that ventilatory parameters are not the sole driver of change in exercise capacity in this study cohort. Investigation over a more prolonged period may delineate the potential interdependencies of the observed discordances over time. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov-NCT01937325.

Partial Functional Diversification of Drosophila melanogaster Septin Genes Sep2 and Sep5.

The septin family of hetero-oligomeric complex-forming proteins can be divided into subgroups, and subgroup members are interchangeable at specific positions in the septin complex. Drosophila melanogaster has five septin genes, including the two SEPT6 subgroup members Sep2 and Sep5 We previously found that Sep2 has a unique function in oogenesis, which is not performed by Sep5 Here, we find that Sep2 is uniquely required for follicle cell encapsulation of female germline cysts, and that Sep2 and Sep5 are redundant for follicle cell proliferation. The five D. melanogaster septins localize similarly in oogenesis, including as rings flanking the germline ring canals. Pnut fails to localize in Sep5; Sep2 double mutant follicle cells, indicating that septin complexes fail to form in the absence of both Sep2 and Sep5. We also find that mutations in septins enhance the mutant phenotype of bazooka, a key component in the establishment of cell polarity, suggesting a link between septin function and cell polarity. Overall, this work suggests that Sep5 has undergone partial loss of ancestral protein function, and demonstrates redundant and unique functions of septins.

Pulmonary and systemic pharmacokinetics of inhaled and intravenous colistin methanesulfonate in cystic fibrosis patients: targeting advantage of inhalational administration.

The purpose of this study was to define the pulmonary and systemic pharmacokinetics of colistin methanesulfonate (CMS) and formed colistin following intravenous (i.v.) and inhaled administration in cystic fibrosis (CF) patients. Six CF subjects were administered nebulized CMS doses of 2 and 4 million IU and an i.v. CMS infusion of 150 mg of colistin base activity. Blood plasma, sputum, and urine samples were collected for 12 to 24 h postdose. To assess the tolerability of the drug, lung function tests, blood serum creatinine concentrations, and adverse effect reports were recorded. All doses were well tolerated in the subjects. The pharmacokinetic parameters for CMS following i.v. delivery were consistent with previously reported values. Sputum concentrations of formed colistin were maintained at <1.0 mg/liter for 12 h postdose. Nebulization of CMS resulted in relatively high sputum concentrations of CMS and formed colistin compared to those resulting from i.v. administration. The systemic availability of CMS was low following nebulization of 2 and 4 million IU (7.93% ± 4.26% and 5.37% ± 1.36%, respectively), and the plasma colistin concentrations were below the limit of quantification. Less than 2 to 3% of the nebulized CMS dose was recovered in the urine samples in 24 h. The therapeutic availability and drug targeting index for CMS and colistin following inhalation compared to i.v. delivery were significantly greater than 1. Inhalation of CMS is an effective means of targeting CMS and formed colistin for delivery to the lungs, as high lung exposure and minimal systemic exposure were achieved in CF subjects.

Evolution of three parent genes and their retrogene copies in Drosophila species.

Retrogenes form a class of gene duplicate lacking the regulatory sequences found outside of the mRNA-coding regions of the parent gene. It is not clear how a retrogene's lack of parental regulatory sequences affects the evolution of the gene pair. To explore the evolution of parent genes and retrogenes, we investigated three such gene pairs in the family Drosophilidae; in Drosophila melanogaster, these gene pairs are CG8331 and CG4960, CG17734 and CG11825, and Sep2 and Sep5. We investigated the embryonic expression patterns of these gene pairs across multiple Drosophila species. Expression patterns of the parent genes and their single copy orthologs are relatively conserved across species, whether or not a species has a retrogene copy, although there is some variation in CG8331 and CG17734. In contrast, expression patterns of the retrogene orthologs have diversified. We used the genome sequences of 20 Drosophila species to investigate coding sequence evolution. The coding sequences of the three gene pairs appear to be evolving predominantly under negative selection; however, the parent genes and retrogenes show some distinct differences in amino acid sequence. Therefore, in general, retrogene expression patterns and coding sequences are distinct compared to their parents and, in some cases, retrogene expression patterns diversify.

Transcriptional regulation of the purine de novo synthesis gene Prat in Drosophila melanogaster.

The first step of the purine de novo synthesis pathway is catalyzed by amidophosphoribosyltransferase (E.C.2.4.2.14) which is encoded by two Prat genes in D. melanogaster, Prat and Prat2. Prat is a retrogene duplication of Prat2, where each gene has a distinct expression pattern. Prat transcription is restricted to proliferating tissues such as imaginal discs and the female germ line. Three conserved putative DNA replication-related element binding factor (DREF) sites lie upstream of the Prat coding region. These elements are upstream of many genes important in cell proliferation. We have found that DREF binds directly upstream of Prat and that the DRE sites associated with its activity are necessary for Prat expression; furthermore, we have determined that a second cis-acting element is present upstream of the Prat gene. Finally, the genes Distal-less, Mi-2 and dMyc, which influence Dref activity, do not appear to affect Prat transcription.

The Drosophila melanogaster septin gene Sep2 has a redundant function with the retrogene Sep5 in imaginal cell proliferation but is essential for oogenesis.

Septins are cytoskeletal proteins that form hetero-oligomeric complexes and function in many biological processes, including cytokinesis. Drosophila melanogaster has five septin genes. Sep5, which is the most recently evolved septin gene in Drosophila, is a retrogene copy of Sep2. Sep5 mutants appear wild type, whereas Sep2 mutant females are semisterile. Their ovaries have egg chambers containing abnormal numbers of nurse cells. The egg chamber phenotype is rescued to wild type by expressing a Sep2 cDNA, but it is only partially rescued by expressing a Sep5 cDNA, showing that these paralogs have diverged in function at the protein level. Sep2 Sep5 double mutants have an early pupal lethal phenotype and lack imaginal discs, suggesting that these genes have redundant functions during imaginal cell proliferation.

A link between impaired purine nucleotide synthesis and apoptosis in Drosophila melanogaster.

The biosynthetic pathways and multiple functions of purine nucleotides are well known. However, the pathways that respond to alterations in purine nucleotide synthesis in vivo in an animal model organism have not been identified. We examined the effects of inhibiting purine de novo synthesis in vivo and in cultured cells of Drosophila melanogaster. The purine de novo synthesis gene ade2 encodes phosphoribosylformylglycinamidine synthase (EC 6.3.5.3). An ade2 deletion, generated by P-element transposon excision, causes lethality in early pupal development, with darkening, or necrosis, of leg and wing imaginal disc tissue upon disc eversion. Together with analysis of a previously isolated weaker allele, ade2(4), and an allele of the Prat gene, which encodes an enzyme for the first step in the pathway, we determined that the lethal arrest and imaginal disc phenotypes involve apoptosis. A transgene expressing the baculovirus caspase inhibitor p35, which suppresses apoptosis caused by other stresses such as DNA damage, suppresses both the imaginal disc tissue darkening and the pupal lethality of all three purine de novo synthesis mutants. Furthermore, we showed the presence of apoptosis at the cellular level in both ade2 and Prat mutants by detecting TUNEL-positive nuclei in wing imaginal discs. Purine de novo synthesis inhibition was also examined in tissue culture by ade2 RNA interference followed by analysis of genome-wide changes in transcript levels. Among the upregulated genes was HtrA2, which encodes an apoptosis effector and is thus a candidate for initiating apoptosis in response to purine depletion.

Modifiers of Prat, a de novo purine synthesis gene, in Drosophila melanogaster.

Drosophila melanogaster was used to identify genes with a potential role in genetic regulation of purine biosynthesis. In this study we examine two dominant genetic modifiers of the essential gene Prat, which encodes amidophosphoribosyltransferase (EC 2.4.2.14). We found that Mod(Prat:bw)3-1 enhances Prat expression only in female heads, whereas Mod(Prat:bw)3-5 suppresses Prat in all stages and tissues examined for both sexes. For Mod-3-5, gene expression microarrays were used to identify other genes that are affected by the modifier. Three mapping approaches were used to localize these modifiers. Deficiency and meiotic mapping showed that the complex lethal complementation group previously associated with Mod-3-1 and Mod-3-5 is actually due to shared second-site lethal mutations. Using male recombination mapping, Mod-3-1 was localized to a 21 kilobase region containing nine genes, and Mod-3-5 was localized to a 53 kilobase region containing eight genes.

Protection of Salmonella by ampicillin-resistant Escherichia coli in the presence of otherwise lethal drug concentrations.

Microbial systems have become the preferred testing grounds for experimental work on the evolution of traits that benefit other group members. This work, based on conceptual and theoretical models of frequency-dependent selection within populations, has proven fruitful in terms of understanding the dynamics of group beneficial or 'public goods' traits within species. Here, we expand the scope of microbial work on the evolution of group-beneficial traits to the case of multi-species communities, particularly those that affect human health. We examined whether beta-lactamase-producing Escherichia coli could protect ampicillin-sensitive cohorts of other species, particularly species that could cause human disease. Both beta-lactamase-secreting E. coli and, surprisingly, those engineered to retain it, allowed for survival of a large number of ampicillin-sensitive cohorts of Salmonella enterica serovar Typhimurium, including both laboratory and clinical isolates. The Salmonella survivors, however, remained sensitive to ampicillin when re-plated onto solid medium and there was no evidence of gene transfer. Salmonella survival did not even require direct physical contact with the resistant E. coli. The observed phenomenon appears to involve increased release of beta-lactamase from the E. coli when present with S. enterica. Significantly, these findings imply that resistant E. coli, that are not themselves pathogenic, may be exploited, even when they are normally selfish with respect to other E. coli. Thus, Salmonella can gain protection against antibiotics from E. coli without gene transfer, a phenomenon not previously known. As a consequence, antibiotic-resistant E. coli can play a decisive role in the survival of a species that causes disease and may thereby interfere with successful treatment.

Evolution of altruists and cheaters in near-isogenic populations of Escherichia coli.

Emergence of antibiotic-resistant bacteria threatens the continued efficacy of many critical drugs used to treat serious infections. What if such resistant organisms could also act as altruists and "share" their resistance with sensitive cohorts without any actual genetic exchange? We competed resistant strains that differ solely in their ability to secrete a plasmid-encoded beta-lactamase. Sensitive strains were otherwise isogenic with their resistant counterparts and were either plasmid-free or contained a "Dummy" plasmid of roughly the same size as that of the resistance plasmids. Absent antibiotic selection, plasmid-free sensitive strains outperformed the plasmid-bearing strains. In the presence of ampicillin, the outcome depended on whether the resistant strain secreted its beta-lactamase (Altruist) or retained it (Selfish). In the latter case, only resistant cells survived. When beta-lactamase was secreted, some sensitive cohorts were also provided protection, with the largest fitness increase provided to plasmid-free cells. However, some Altruist strains appeared to be at a disadvantage, as a great deal of their enzyme broke off cells. Thus, additional variables must be considered when designing microbial competition experiments.

Expression pattern diversity and functional conservation between retroposed PRAT genes from Drosophila melanogaster and Drosophila virilis.

Gene duplication by retrotransposition duplicates only the coding and untranslated regions of a gene and, thus, biases retroduplicated genes toward having different expression patterns from their parental genes. As such, genes duplicated by retrotransposition are more likely to develop novel expression domains. To explore this idea further, we used the Prat/Prat2 gene duplication in Drosophila as a case study to examine the aftermath of a retrotransposition event that resulted in both the parent and the child gene becoming essential for survival. We used the Gal4-UAS transgene system with EGFP as a reporter to determine the developmental expression patterns of Prat and Prat2 from D. melanogaster (DmPrat and DmPrat2) and Prat from D. virilis (DvPrat). We also tested the functional equivalence of the protein products of DmPrat and DmPrat2. We found that each of the proteins could rescue DmPrat mutations, showing that the requirement for both Prat and Prat2 in Drosophila is not simply due to differences in protein function. In contrast, we found that the DmPrat and DmPrat2 genes have developed nonoverlapping patterns of expression, which correlate with their respective loss-of-function phenotypes. We further found that DvPrat expression is similar to DmPrat during development but differs in adult gonads. Thus, the function of the Prat retrogene has not diverged in the D. melanogaster and D. virilis lineages, while some aspects of its expression pattern have evolved. Finally, we have identified promoter elements, conserved upstream of DmPrat and DvPrat, that this retrogene has acquired to drive its expression.

The benign course of liver disease in adults with cystic fibrosis and the effect of ursodeoxycholic acid.

BACKGROUND AND AIMS: The life expectancy of patients with cystic fibrosis (CF) has been increasing and the associated liver disease has emerged as a significant medical issue. Our aim was to describe the clinical features, course and effect of ursodeoxycholic acid (UDCA) on liver disease in an adult CF population. STUDY: From 1983 to 2005, 278 patients with CF were followed up at the Alfred Hospital, an adult tertiary referral centre. Twenty-seven patients (9.7%) satisfied the criteria for liver disease and their clinico-pathological features were assessed. The effect of UDCA on hepatobiliary symptoms and biochemical parameters was determined. RESULTS: The mean age at liver disease diagnosis was 23 years (range 8-47 years). Portal hypertension was present in 18 (67%) patients. During a median follow-up of 7 years (range 1.5-15), variceal haemorrhage occurred in two patients and ascites in three (one spontaneously). Nine (33%) patients died and five (19%) underwent lung transplantation. There was no encephalopathy, liver transplantation or liver-related deaths. UDCA was taken by 22 patients and was associated with a significant improvement in hepatobiliary symptoms [11/22 (50%) in the pre-UDCA period vs 1/22 (4%) in the post-UDCA period; P=0.0003] and a significant reduction in aspartate aminotransferase (P=0.005); alanine aminotransferase (P<0.001); gamma-glutamyltranspeptidase (P=0.021); and alkaline phosphatase (P<0.001). CONCLUSIONS: Liver disease in adults with CF is commonly complicated by portal hypertension, but morbidity and mortality associated with this in our small patient population were low. UDCA is associated with improvement in hepatobiliary symptoms and liver function tests.

An artificial mitochondrial tail signal/anchor sequence confirms a requirement for moderate hydrophobicity for targeting.

Tail-anchored proteins are a group of membrane proteins oriented with their amino terminus in the cytoplasm and their carboxy terminus embedded in intracellular membranes. This group includes the apoptosis-mediating proteins of the Bcl-2 family as well as the vesicle targeting proteins of the SNARE group, among others. A stretch of hydrophobic amino acids at the extreme carboxy terminus of these proteins serves both as a membrane anchor and as a targeting signal. Tail-anchored proteins are differentially targeted to either the endoplasmic reticulum or the mitochondrial outer membrane and the mechanism which accomplishes this selective targeting is poorly understood. Here we define important characteristics of the signal/anchor region which directs proteins to the mitochondrial outer membrane. We have created an artificial sequence consisting of a stretch of 16 leucines bounded by positively charged amino acids. Using this template we demonstrate that moderate hydrophobicity distinguishes the mitochondrial tail-anchor sequence from that of the endoplasmic reticulum tail-anchor sequence. A change as small as introduction of a single polar residue into a sequence that otherwise targets to the endoplasmic reticulum can substantially switch targeting to the mitochondrial outer membrane. Further we show that a mitochondrially targeted tail-anchor has a higher propensity for the formation of alpha-helical structure than a sequence directing tail-anchored proteins to the endoplasmic reticulum.

Parent genes of retrotransposition-generated gene duplicates in Drosophila melanogaster have distinct expression profiles.

Genes arising by retrotransposition are always different from their parent genes from the outset. In addition, the cDNA must insert into a region that allows expression or it will become a processed pseudogene. We sought to determine whether this class of gene duplication differs from other gene duplications based on functional criteria. Using amino acid sequences from Drosophila melanogaster, we identified retroduplicated gene pairs at various levels of sequence identity. Analysis of gene ontology annotations showed some enrichment of retroduplications in the cellular physiological processes class. Retroduplications show a higher level of nucleotide substitution than other gene duplications, suggesting a higher rate of divergence. Remarkably, analysis of microarray data for gene expression during embryogenesis showed that parent genes are more highly expressed relative to their retroduplicated copies, tandem duplications, and all genes. Furthermore, an expressed sequence tag library representation shows a broader distribution for parent genes than for all other genes and, as found previously by others, retroduplicated gene transcripts are found most abundantly in testes. Therefore, in examining retroduplicated gene pairs, we have found that parent genes of retroduplications are also a distinctive class in terms of transcript expression levels and distribution.

Interleukin-10 production after pro-inflammatory stimulation of neutrophils and monocytic cells of the newborn. Comparison to exogenous interleukin-10 and dexamethasone levels needed to inhibit chemokine release.

BACKGROUND: Neutrophils followed by monocytic cells are recruited into the lung during the early development of bronchopulmonary dysplasia (BPD). OBJECTIVES: We determined: (1) the capacity of polymorphonuclear leukocytes (PMNs) and peripheral blood monocytic cells (PBMCs) of the newborn to produce and release the anti-inflammatory cytokine, interleukin (IL)-10, after stimulation by lipopolysaccharide (LPS) or tumor necrosis factor (TNF), and (2) the levels of exogenous IL-10 and/or dexamethasone (DEX) needed to inhibit the release of the pro-inflammatory chemokine IL-8 from stimulated cells. METHODS: PMNs and PBMCs were isolated from cord blood of healthy term infants. RT-PCR and ELISA were used to detect mRNA and cytokine levels from culture media, respectively. RESULTS: We found that PMNs did not produce IL-10 mRNA or release IL-10 but did produce IL-8 mRNA by 1 h. PBMCs did produce IL-10 mRNA after 4 h (with IL-8 mRNA expression by 1 h). LPS-stimulated PBMCs released IL-10 to a maximum of 1,038 pg/ml/5 million cells (56 femtomolar). Equimolar doses of exogenous IL-10 or DEX produced up to 83% inhibition of IL-8 from PMNs. Exogenous IL-10 was more potent than DEX, on an equimolar basis, with regard to IL-8 release from PBMCs (90 vs. 33% respectively at a 10 nanomolar level). No inhibition of IL-8 release by IL-10 or DEX was observed at 100 femtomolar level. IL-10 and DEX did not have an additive inhibitory effect on IL-8 release. CONCLUSIONS: We conclude that for the newborn: (1) PBMCs produce IL-10 far below the level needed to inhibit a submaximal release of IL-8 from PMNs or PBMCs, and (2) exogenous IL-10 was equipotent or more potent than therapeutic levels of DEX on inhibition of IL-8 from these cells. Further studies are needed to determine if exogenous IL-10 may be useful in the treatment of BPD or other inflammatory disorders of the newborn.