The kinase mTOR modulates the antibody response to provide cross-protective immunity to lethal infection with influenza virus.

Highly pathogenic avian influenza viruses pose a continuing global threat. Current vaccines will not protect against newly evolved pandemic viruses. The creation of 'universal' vaccines has been unsuccessful because the immunological mechanisms that promote heterosubtypic immunity are incompletely defined. We found here that rapamycin, an immunosuppressive drug that inhibits the kinase mTOR, promoted cross-strain protection against lethal infection with influenza virus of various subtypes when administered during immunization with influenza virus subtype H3N2. Rapamycin reduced the formation of germinal centers and inhibited class switching in B cells, which yielded a unique repertoire of antibodies that mediated heterosubtypic protection. Our data established a requirement for the mTORC1 complex in B cell class switching and demonstrated that rapamycin skewed the antibody response away from high-affinity variant epitopes and targeted more conserved elements of hemagglutinin. Our findings have implications for the design of a vaccine against influenza virus.

Vacuolar H+-ATPase dysfunction rescues intralumenal vesicle cargo sorting in yeast lacking PI(3,5)P2 or Doa4.

Endosomes undergo a maturation process highlighted by a reduction in lumenal pH, a conversion of surface markers that prime endosome-lysosome fusion and the sequestration of ubiquitylated transmembrane protein cargos within intralumenal vesicles (ILVs). We investigated ILV cargo sorting in mutant strains of the budding yeast Saccharomyces cerevisiae that are deficient for either the lysosomal/vacuolar signaling lipid PI(3,5)P2 or the Doa4 ubiquitin hydrolase that deubiquitylates ILV cargos. Disruption of PI(3,5)P2 synthesis or Doa4 function causes a defect in sorting of a subset of ILV cargos. We show that these cargo-sorting defects are suppressed by mutations that disrupt Vph1, a subunit of vacuolar H+-ATPase (V-ATPase) complexes that acidify late endosomes and vacuoles. We further show that Vph1 dysfunction increases endosome abundance, and disrupts vacuolar localization of Ypt7 and Vps41, two crucial mediators of endosome-vacuole fusion. Because V-ATPase inhibition attenuates this fusion and rescues the ILV cargo-sorting defects in yeast that lack PI(3,5)P2 or Doa4 activity, our results suggest that the V-ATPase has a role in coordinating ILV cargo sorting with the membrane fusion machinery. This article has an associated First Person interview with the first author of the paper.

Natriuretic peptide receptor-C mediates the inhibitory effect of atrial natriuretic peptide on neutrophil recruitment to the lung during acute lung injury.

Atrial natriuretic peptide (ANP) protects against acute lung injury (ALI), but the receptor that mediates this effect is not known. Transgenic mice with 0 (knockout), 1 (heterozygote), or 2 (wild-type) functional copies of Npr3, the gene that encodes for natriuretic peptide receptor-C (NPR-C), were treated with intravenous infusion of ANP or saline vehicle before oropharyngeal aspiration of Pseudomonas aeruginosa (PA103) or saline vehicle. Lung injury was assessed 4 h following aspiration by measurement of lung wet/dry (W/D) weight, whole lung leukocyte and cytokine levels, and protein, leukocyte, and cytokine concentration in bronchoalveolar lavage fluid (BALF). PA103 induced acute lung injury as evidenced by increases in lung W/D ratio and protein concentration in BALF. The severity of PA103-induced lung injury did not differ between NPR-C genotypes. Treatment with intravenous ANP infusion reduced PA103-induced increases in lung W/D and BALF protein concentration in all three NPRC genotypes. PA103 increased the percentage of leukocytes that were neutrophils and cytokine levels in whole lung and BALF in NPR-C wild-type and knockout mice. This effect was blunted by ANP in wild-type mice but not in the NPR-C knockout mice. NPR-C does not mediate the protective effect of ANP on endothelial cell permeability in settings of PA103-induced injury but may mediate the effect of ANP on inhibition of the recruitment of neutrophils to the lung and thereby attenuate the release of inflammatory cytokines.

Lessons learned from a delayed diagnosis of atrioesophageal fistula: A multidisciplinary approach.

Atrioesophageal fistulas are a rare complication of radiofrequency ablation (RFA) that requires rapid identification and emergent surgical repair to prevent morbidity and mortality. We report a case of a 32-year-old man with atrial fibrillation presenting with chest pain followed by rapidly progressive sepsis and embolic cerebrovascular accident 23 days after RFA. Subtle initially overlooked findings on multiple computed tomography caused a delay in diagnosis. Atrioesophageal fistulas remain diagnostically challenging. A high index of suspicion coupled with serial computed tomography of the chest with intravenous and oral contrast reviewed by a multimodal team is essential to make a timely diagnosis.

Towards sustainable additive manufacturing: The need for awareness of particle and vapor releases during polymer recycling, making filament, and fused filament fabrication 3-D printing.

Fused filament fabrication three-dimensional (FFF 3-D) printing is thought to be environmentally sustainable; however, significant amounts of waste can be generated from this technology. One way to improve its sustainability is via distributed recycling of plastics in homes, schools, and libraries to create feedstock filament for printing. Risks from exposures incurred during recycling and reuse of plastics has not been incorporated into life cycle assessments. This study characterized contaminant releases from virgin (unextruded) and recycled plastics from filament production through FFF 3-D printing. Waste polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) plastics were recycled to create filament; virgin PLA, ABS, high and low density polyethylenes, high impact polystyrene, and polypropylene pellets were also extruded into filament. The release of particles and chemicals into school classrooms was evaluated using standard industrial hygiene methodologies. All tasks released particles that contained hazardous metals (e.g., manganese) and with size capable of depositing in the gas exchange region of the lung, i.e., granulation of waste PLA and ABS (667 to 714 nm) and filament making (608 to 711 nm) and FFF 3-D printing (616 to 731 nm) with waste and virgin plastics. All tasks released vapors, including respiratory irritants and potential carcinogens (benzene and formaldehyde), mucus membrane irritants (acetone, xylenes, ethylbenzene, and methyl methacrylate), and asthmagens (styrene, multiple carbonyl compounds). These data are useful for incorporating risks of exposure to hazardous contaminants in future life cycle evaluations to demonstrate the sustainability and circular economy potential of FFF 3-D printing in distributed spaces.

Global identification of S-palmitoylated proteins and detection of palmitoylating (DHHC) enzymes in heart.

High-throughput experiments suggest that almost 20% of human proteins may be S-palmitoylatable, a post-translational modification (PTM) whereby fatty acyl chains, most commonly palmitoyl chain, are linked to cysteine thiol groups that impact on protein trafficking, distribution and function. In human, protein S-palmitoylation is mediated by a group of 23 palmitoylating 'Asp-His-His-Cys' domain-containing (DHHC) enzymes. There is no information on the scope of protein S-palmitoylation, or the pattern of DHHC enzyme expression, in the heart. We used resin-assisted capture to pull down S-palmitoylated proteins from human, dog, and rat hearts, followed by proteomic search to identify proteins in the pulldowns. We identified 454 proteins present in at least 2 species-specific pulldowns. These proteins are operationally called 'cardiac palmitoylome'. Enrichment analysis based on Gene Ontology terms 'cellular component' indicated that cardiac palmitoylome is involved in cell-cell and cell-substrate junctions, plasma membrane microdomain organization, vesicular trafficking, and mitochondrial enzyme organization. Importantly, cardiac palmitoylome is uniquely enriched in proteins participating in the organization and function of t-tubules, costameres and intercalated discs, three microdomains critical for excitation-contraction coupling and intercellular communication of cardiomyocytes. We validated antibodies targeting DHHC enzymes, and detected eleven of them expressed in hearts across species. In conclusion, we provide resources useful for investigators interested in studying protein S-palmitoylation and its regulation by DHHC enzymes in the heart. We also discuss challenges in these efforts, and suggest methods and tools that should be developed to overcome these challenges.

Delayed KCNQ1/KCNE1 assembly on the cell surface helps IKs fulfil its function as a repolarization reserve in the heart.

KEY POINTS: In adult ventricular myocytes, the slow delayed rectifier (IKs ) channels are distributed on the surface sarcolemma, not t-tubules. In adult ventricular myocytes, KCNQ1 and KCNE1 have distinct cell surface and cytoplasmic pools. KCNQ1 and KCNE1 traffic from the endoplasmic reticulum to the plasma membrane by separate routes, and assemble into IKs channels on the cell surface. Liquid chromatography/tandem mass spectrometry applied to affinity-purified KCNQ1 and KCNE1 interacting proteins reveals novel interactors involved in protein trafficking and assembly. Microtubule plus-end binding protein 1 (EB1) binds KCNQ1 preferentially in its dimer form, and promotes KCNQ1 to reach the cell surface. An LQT1-associated mutation, Y111C, reduces KCNQ1 binding to EB1 dimer. ABSTRACT: Slow delayed rectifier (IKs ) channels consist of KCNQ1 and KCNE1. IKs functions as a 'repolarization reserve' in the heart by providing extra current for ventricular action potential shortening during ß-adrenergic stimulation. There has been much debate about how KCNQ1 and KCNE1 traffic in cells, where they associate to form IKs channels, and the distribution pattern of IKs channels relative to ß-adrenergic signalling complex. We used experimental strategies not previously applied to KCNQ1, KCNE1 or IKs , to provide new insights into these issues. 'Retention-using-selected-hook' experiments showed that newly translated KCNE1 constitutively trafficked through the conventional secretory path to the cell surface. KCNQ1 largely stayed in the endoplasmic reticulum, although dynamic KCNQ1 vesicles were observed in the submembrane region. Disulphide-bonded KCNQ1/KCNE1 constructs reported preferential association after they had reached cell surface. An in situ proximity ligation assay detected IKs channels in surface sarcolemma but not t-tubules of ventricular myocytes, similar to the reported location of adenylate cyclase 9/yotiao. Fluorescent protein-tagged KCNQ1 and KCNE1, in conjunction with antibodies targeting their extracellular epitopes, detected distinct cell surface and cytoplasmic pools of both proteins in myocytes. We conclude that, in cardiomyocytes, KCNQ1 and KCNE1 traffic by different routes to surface sarcolemma where they assemble into IKs channels. This mode of delayed channel assembly helps IKs fulfil its function of repolarization reserve. Proteomic experiments revealed a novel KCNQ1 interactor, microtubule plus-end binding protein 1 (EB1). EB1 dimer (active form) bound KCNQ1 and increased its surface level. An LQT1 mutation, Y111C, reduced KCNQ1 binding to EB1 dimer.

Delta-S-Cys-Albumin: A Lab Test that Quantifies Cumulative Exposure of Archived Human Blood Plasma and Serum Samples to Thawed Conditions.

Exposure of blood plasma/serum (P/S) to thawed conditions (> -30 °C) can produce biomolecular changes that skew measurements of biomarkers within archived patient samples, potentially rendering them unfit for molecular analysis. Because freeze-thaw histories are often poorly documented, objective methods for assessing molecular fitness before analysis are needed. We report a 10-µl, dilute-and-shoot, intact-protein mass spectrometric assay of albumin proteoforms called "ΔS-Cys-Albumin" that quantifies cumulative exposure of archived P/S samples to thawed conditions. The relative abundance of S-cysteinylated (oxidized) albumin in P/S increases inexorably but to a maximum value under 100% when samples are exposed to temperatures > -30 °C. The difference in the relative abundance of S-cysteinylated albumin (S-Cys-Alb) before and after an intentional incubation period that drives this proteoform to its maximum level is denoted as ΔS-Cys-Albumin. ΔS-Cys-Albumin in fully expired samples is zero. The range (mean ± 95% CI) observed for ΔS-Cys-Albumin in fresh cardiac patient P/S (n = 97) was, for plasma 12-29% (20.9 ± 0.75%) and for serum 10-24% (15.5 ± 0.64%). The multireaction rate law that governs S-Cys-Alb formation in P/S was determined and shown to predict the rate of formation of S-Cys-Alb in plasma and serum samples-a step that enables back-calculation of the time at which unknown P/S specimens have been exposed to room temperature. A blind challenge demonstrated that ΔS-Cys-Albumin can detect exposure of groups (n = 6 each) of P/S samples to 23 °C for 2 h, 4 °C for 16 h, or -20 °C for 24 h-and exposure of individual specimens for modestly increased times. An unplanned case study of nominally pristine serum samples collected under NIH-sponsorship demonstrated that empirical evidence is required to ensure accurate knowledge of archived P/S biospecimen storage history.

PAD4 Deficiency Leads to Decreased Organ Dysfunction and Improved Survival in a Dual Insult Model of Hemorrhagic Shock and Sepsis.

Indirect acute respiratory distress syndrome (iARDS) is caused by a nonpulmonary inflammatory process resulting from insults such as nonpulmonary sepsis. Neutrophils are thought to play a significant role in mediating ARDS, with the development of iARDS being characterized by dysregulation and recruitment of activated neutrophils into the lung. Recently, a novel mechanism of microbial killing by neutrophils was identified through the formation of neutrophil extracellular traps (NETs). NETs are composed of large webs of decondensed chromatin released from activated neutrophils into the extracellular space; they are regulated by the enzyme peptidylarginine deiminase 4 (PAD4) through mediation of chromatin decondensation via citrullination of target histones. Components of NETs have been implicated in ARDS. However, it is unknown whether there is any pathological significance of NET formation in ARDS caused indirectly by nonpulmonary insult. We subjected PAD4-/- mice and wild-type mice to a "two-hit" model of hypovolemic shock (fixed-pressure hemorrhage [Hem]) followed by septic cecal ligation and puncture (CLP) insult (Hem/CLP). Mice were hemorrhaged and resuscitated; 24 h after Hem, mice were then subjected to CLP. Overall, PAD4 deletion led to an improved survival as compared with wild-type mice. PAD4-/- mice displayed a marked decrease in neutrophil influx into the lung, as well decreased presence of proinflammatory mediators. PAD4-/- mice were also able to maintain baseline kidney function after Hem/CLP. These data taken together suggest PAD4-mediated NET formation contributes to the mortality associated with shock/sepsis and may play a role in the pathobiology of end organ injury in response to combined hemorrhage plus sepsis.

CBD-1 organizes two independent complexes required for eggshell vitelline layer formation and egg activation in C. elegans.

Metazoan eggs have a specialized coat of extracellular matrix that aids in sperm-egg recognition. The coat is rapidly remodeled after fertilization to prevent polyspermy and establish a more permanent barrier to protect the developing embryo. In nematodes, this coat is called the vitelline layer, which is remodeled into the outermost layer of a rigid and impermeable eggshell. We have identified three key components of the vitelline layer structural scaffold - PERM-2, PERM-4 and CBD-1, the first such proteins to be described in the nematode C. elegans. CBD-1 tethered PERM-2 and PERM-4 to the nascent vitelline layer via two N-terminal chitin-binding domains. After fertilization, all three proteins redistributed from the zygote surface to the outer eggshell. Depletion of PERM-2 and PERM-4 from the scaffold led to a porous vitelline layer that permitted soluble factors to leak through the eggshell and resulted in embryonic death. In addition to its role in vitelline layer assembly, CBD-1 is also known to anchor a protein complex required for fertilization and egg activation (EGG-1-5/CHS-1/MBK-2). We found the PERM complex and EGG complex to be functionally independent, and structurally organized through distinct domains of CBD-1. CBD-1 is thus a multifaceted regulator that promotes distinct aspects of vitelline layer assembly and egg activation. In sum, our findings characterize the first vitelline layer components in nematodes, and provide a foundation through which to explore both conserved and species-specific strategies used by animals to build protective barriers following fertilization.

CD177 modulates human neutrophil migration through activation-mediated integrin and chemoreceptor regulation.

CD177 is a glycosylphosphatidylinositol (GPI)-anchored protein expressed by a variable proportion of human neutrophils that mediates surface expression of the antineutrophil cytoplasmic antibody antigen proteinase 3. CD177 associates with ß2 integrins and recognizes platelet endothelial cell adhesion molecule 1 (PECAM-1), suggesting a role in neutrophil migration. However, CD177pos neutrophils exhibit no clear migratory advantage in vivo, despite interruption of in vitro transendothelial migration by CD177 ligation. We sought to understand this paradox. Using a PECAM-1-independent transwell system, we found that CD177pos and CD177neg neutrophils migrated comparably. CD177 ligation selectively impaired migration of CD177pos neutrophils, an effect mediated through immobilization and cellular spreading on the transwell membrane. Correspondingly, CD177 ligation enhanced its interaction with ß2 integrins, as revealed by fluorescence lifetime imaging microscopy, leading to integrin-mediated phosphorylation of Src and extracellular signal-regulated kinase (ERK). CD177-driven cell activation enhanced surface ß2 integrin expression and affinity, impaired internalization of integrin attachments, and resulted in ERK-mediated attenuation of chemokine signaling. We conclude that CD177 signals in a ß2 integrin-dependent manner to orchestrate a set of activation-mediated mechanisms that impair human neutrophil migration.

Activated ß2 Integrins Restrict Neutrophil Recruitment during Murine Acute Pseudomonal Pneumonia.

Rapid neutrophil recruitment is critical for the efficient clearance of bacterial pathogens from the lungs. Although ß2 integrins and their activation are required for neutrophil recruitment from postcapillary venules of the systemic circulation into inflamed tissues, the involvement of integrins in neutrophil recruitment in response to respiratory infection varies among bacterial pathogens. For stimuli eliciting ß2 integrin-dependent neutrophil influx, including Pseudomonas aeruginosa, it remains unclear whether the activation of ß2 integrins is an essential step in this process. In the current study, we analyze neutrophil trafficking within the lungs of mice infected with Pseudomonas aeruginosa and evaluate the role of ß2 integrin activation through genetic deletion of talin-1 or Kindlin-3 or by pharmacological inhibition of high-affinity ß2 integrins using a small molecule allosteric antagonist. We observe that attenuation of high-affinity ß2 integrins leads to an enhancement of neutrophil emigration into lung interstitium and airspaces. Neutrophil effector functions, including the production of reactive oxygen species and the phagocytosis of bacteria, are only partially dependent on high-affinity ß2 integrins. These results reveal a mechanism by which activated ß2 integrins limit neutrophil entry into the lung tissue and airspaces during acute pseudomonal pneumonia and suggest potential strategies for modulating neutrophil-mediated host defense.

High-Resolution Inflorescence Phenotyping Using a Novel Image-Analysis Pipeline, PANorama.

Variation in inflorescence development is an important target of selection for numerous crop species, including many members of the Poaceae (grasses). In Asian rice (Oryza sativa), inflorescence (panicle) architecture is correlated with yield and grain-quality traits. However, many rice breeders continue to use composite phenotypes in selection pipelines, because measuring complex, branched panicles requires a significant investment of resources. We developed an open-source phenotyping platform, PANorama, which measures multiple architectural and branching phenotypes from images simultaneously. PANorama automatically extracts skeletons from images, allows users to subdivide axes into individual internodes, and thresholds away structures, such as awns, that normally interfere with accurate panicle phenotyping. PANorama represents an improvement in both efficiency and accuracy over existing panicle imaging platforms, and flexible implementation makes PANorama capable of measuring a range of organs from other plant species. Using high-resolution phenotypes, a mapping population of recombinant inbred lines, and a dense single-nucleotide polymorphism data set, we identify, to our knowledge, the largest number of quantitative trait loci (QTLs) for panicle traits ever reported in a single study. Several areas of the genome show pleiotropic clusters of panicle QTLs, including a region near the rice Green Revolution gene SEMIDWARF1. We also confirm that multiple panicle phenotypes are distinctly different among a small collection of diverse rice varieties. Taken together, these results suggest that clusters of small-effect QTLs may be responsible for varietal or subpopulation-specific panicle traits, representing a significant opportunity for rice breeders selecting for yield performance across different genetic backgrounds.

Substrate inhibition of uracil phosphoribosyltransferase by uracil can account for the uracil growth sensitivity of Leishmania donovani pyrimidine auxotrophs.

The pathogenic protozoan parasite Leishmania donovani is capable of both de novo pyrimidine biosynthesis and salvage of pyrimidines from the host milieu. Genetic analysis has authenticated L. donovani uracil phosphoribosyltransferase (LdUPRT), an enzyme not found in mammalian cells, as the focal enzyme of pyrimidine salvage because all exogenous pyrimidines that can satisfy the requirement of the parasite for pyrimidine nucleotides are funneled to uracil and then phosphoribosylated to UMP in the parasite by LdUPRT. To characterize this unique parasite enzyme, LdUPRT was expressed in Escherichia coli, and the recombinant enzyme was purified to homogeneity. Kinetic analysis revealed apparent Km values of 20 and 99 µM for the natural substrates uracil and phosphoribosylpyrophosphate, respectively, as well as apparent Km values 6 and 7 µM for the pyrimidine analogs 5-fluorouracil and 4-thiouracil, respectively. Size exclusion chromatography revealed the native LdUPRT to be tetrameric and retained partial structure and activity in high concentrations of urea. L. donovani mutants deficient in de novo pyrimidine biosynthesis, which require functional LdUPRT for growth, are hypersensitive to high concentrations of uracil, 5-fluorouracil, and 4-thiouracil in the growth medium. This hypersensitivity can be explained by the observation that LdUPRT is substrate-inhibited by uracil and 4-thiouracil, but 5-fluorouracil toxicity transpires via an alternative mechanism. This substrate inhibition of LdUPRT provides a protective mechanism for the parasite by facilitating purine and pyrimidine nucleotide pool balance and by sparing phosphoribosylpyrophosphate for consumption by the nutritionally indispensable purine salvage process.

Blood Volume Analysis of Total Artificial Heart Recipients: A Case Series.

Blood volume analysis provides a quantitative volume assessment in patients with equivocal or discordant clinical findings. Reports on its use in mechanical circulatory support are limited and it has never been described in patients with a total artificial heart. Our series demonstrates that patients supported with total artificial heart as a bridge to transplant have significant reductions in red blood cell volume and heterogeneous adaptations in their total blood volume and plasma volume. Pathologic derangements in our patient's total blood volume were targeted to restore euvolemia.

The phospholipids cardiolipin and phosphatidylethanolamine differentially regulate MDC biogenesis.

Cells utilize multiple mechanisms to maintain mitochondrial homeostasis. We recently characterized a pathway that remodels mitochondria in response to metabolic alterations and protein overload stress. This remodeling occurs via the formation of large membranous structures from the mitochondrial outer membrane called mitochondrial-derived compartments (MDCs), which are eventually released from mitochondria and degraded. Here, we conducted a microscopy-based screen in budding yeast to identify factors that regulate MDC formation. We found that two phospholipids, cardiolipin (CL) and phosphatidylethanolamine (PE), differentially regulate MDC biogenesis. CL depletion impairs MDC biogenesis, whereas blocking mitochondrial PE production leads to constitutive MDC formation. Additionally, in response to metabolic MDC activators, cellular and mitochondrial PE declines, and overexpressing mitochondrial PE synthesis enzymes suppress MDC biogenesis. Altogether, our data indicate a requirement for CL in MDC biogenesis and suggest that PE depletion may stimulate MDC formation downstream of MDC-inducing metabolic stress.

Persistent PKA activation redistributes NaV1.5 to the cell surface of adult rat ventricular myocytes.

During chronic stress, persistent activation of cAMP-dependent protein kinase (PKA) occurs, which can contribute to protective or maladaptive changes in the heart. We sought to understand the effect of persistent PKA activation on NaV1.5 channel distribution and function in cardiomyocytes using adult rat ventricular myocytes as the main model. PKA activation with 8CPT-cAMP and okadaic acid (phosphatase inhibitor) caused an increase in Na+ current amplitude without altering the total NaV1.5 protein level, suggesting a redistribution of NaV1.5 to the myocytes' surface. Biotinylation experiments in HEK293 cells showed that inhibiting protein trafficking from intracellular compartments to the plasma membrane prevented the PKA-induced increase in cell surface NaV1.5. Additionally, PKA activation induced a time-dependent increase in microtubule plus-end binding protein 1 (EB1) and clustering of EB1 at myocytes' peripheral surface and intercalated discs (ICDs). This was accompanied by a decrease in stable interfibrillar microtubules but an increase in dynamic microtubules along the myocyte surface. Imaging and coimmunoprecipitation experiments revealed that NaV1.5 interacted with EB1 and ß-tubulin, and both interactions were enhanced by PKA activation. We propose that persistent PKA activation promotes NaV1.5 trafficking to the peripheral surface of myocytes and ICDs by providing dynamic microtubule tracks and enhanced guidance by EB1. Our proposal is consistent with an increase in the correlative distribution of NaV1.5, EB1, and ß-tubulin at these subcellular domains in PKA-activated myocytes. Our study suggests that persistent PKA activation, at least during the initial phase, can protect impulse propagation in a chronically stressed heart by increasing NaV1.5 at ICDs.

Effectiveness of exercise modalities on breast cancer patient outcomes: a systematic review and meta-analysis.

BACKGROUND: The effects of exercise in patients with breast cancer (BC), has shown some profit, but consistency and magnitude of benefit remains unclear. We aimed to conduct a meta-analysis to assess the benefits of varying types of exercises in patients with BC. METHODS: Literature search was conducted across five electronic databases (MEDLINE, Web of Science, Scopus, Google Scholar and Cochrane) from 1st January 2000 through 19th January 2024. Randomized controlled trials (RCTs) assessing the impact of different types of exercise on outcomes related to fitness and quality of life (QOL) in patients with BC were considered for inclusion. Outcomes of interest included cardiorespiratory fitness (CRF), health-related quality of life (HRQOL), muscle strength, fatigue and physical function. Evaluations were reported as mean differences (MDs) with 95% confidence intervals (CIs) and pooled using random effects model. A p value < 0.05 was considered significant. RESULTS: Thirty-one relevant articles were included in the final analysis. Exercise intervention did not significantly improved the CRF in patients with BC when compared with control according to treadmill ergometer scale (MD: 4.96; 95%Cl [-2.79, 12.70]; P = 0.21), however exercise significantly improved CRF according to cycle ergometer scales (MD 2.07; 95% Cl [1.03, 3.11]; P = 0.0001). Physical function was significantly improved as well in exercise group reported by 6-MWT scale (MD 80.72; 95% Cl [55.67, 105.77]; P < 0.00001). However, exercise did not significantly improve muscle strength assessed using the hand grip dynamometer (MD 0.55; 95% CI [-1.61, 2.71]; P = 0.62), and fatigue assessed using the MFI-20 (MD -0.09; 95% CI [-5.92, 5.74]; P = 0.98) and Revised Piper scales (MD -0.26; 95% CI [-1.06, 0.55] P = 0.53). Interestingly, exercise was found to improve HRQOL when assessed using the FACT-B scale (MD 8.57; 95% CI [4.53, 12.61]; P < 0.0001) but no significant improvements were noted with the EORTIC QLQ-C30 scale (MD 1.98; 95% CI [-1.43, 5.40]; P = 0.25). CONCLUSION: Overall exercise significantly improves the HRQOL, CRF and physical function in patients with BC. HRQOL was improved with all exercise types but the effects on CRF vary with cycle versus treadmill ergometer. Exercise failed to improve fatigue-related symptoms and muscle strength. Large RCTs are required to evaluate the effects of exercise in patients with BC in more detail.

Genetic dissection of pyrimidine biosynthesis and salvage in Leishmania donovani.

Protozoan parasites of the Leishmania genus express the metabolic machinery to synthesize pyrimidine nucleotides via both de novo and salvage pathways. To evaluate the relative contributions of pyrimidine biosynthesis and salvage to pyrimidine homeostasis in both life cycle stages of Leishmania donovani, individual mutant lines deficient in either carbamoyl phosphate synthetase (CPS), the first enzyme in pyrimidine biosynthesis, uracil phosphoribosyltransferase (UPRT), a salvage enzyme, or both CPS and UPRT were constructed. The Δcps lesion conferred pyrimidine auxotrophy and a growth requirement for medium supplementation with one of a plethora of pyrimidine nucleosides or nucleobases, although only dihydroorotate or orotate could circumvent the pyrimidine auxotrophy of the Δcps/Δuprt double knockout. The Δuprt null mutant was prototrophic for pyrimidines but could not salvage uracil or any pyrimidine nucleoside. The capability of the Δcps parasites to infect mice was somewhat diminished but still robust, indicating active pyrimidine salvage by the amastigote form of the parasite, but the Δcps/Δuprt mutant was completely attenuated with no persistent parasites detected after a 4-week infection. Complementation of the Δcps/Δuprt clone with either CPS or UPRT restored infectivity. These data establish that an intact pyrimidine biosynthesis pathway is essential for the growth of the promastigote form of L. donovani in culture, that all uracil and pyrimidine nucleoside salvage in the parasite is mediated by UPRT, and that both the biosynthetic and salvage pathways contribute to a robust infection of the mammalian host by the amastigote. These findings impact potential therapeutic design and vaccine strategies for visceral leishmaniasis.

Migratory biliary stent resulting in colonic perforation: a rare complication and review of literature.

Biliary stent insertion during endoscopic retrograde cholangiopancreatography is used as a therapeutic intervention allowing flow of bile into the duodenum. In rare circumstances, distal gastrointestinal perforation can be attributed to a migrated biliary stent, with the most common site being the sigmoid colon. In these cases, surgical and/or endoscopic intervention may be required. We report a case of a 98-year-old male presenting with small bowel obstruction secondary to migrated plastic and metal biliary stents placed for acute biliary pancreatitis. Due to advanced age and high-risk multiple comorbidities, conservative management was undertaken. The patient was discharged after 5 days after ongoing pain and obstipation with palliative care services in place.