Lack of polyamines leads to cotranslational degradation of the general stress factor RpoS in Escherichia coli.

The specialized sigma factor RpoS mediates a general stress response in Escherichia coli and related bacteria, activating promoters that allow cells to survive stationary phase and many stresses. RpoS synthesis and stability are regulated at multiple levels. Translation of RpoS is positively regulated by multiple small RNAs in response to stress. Degradation of RpoS, dependent upon the adaptor protein RssB, is rapid during exponential growth and ceases upon starvation or other stresses, increasing accumulation of RpoS. E. coli carrying mutations that block the synthesis of polyamines were previously found to have low levels of RpoS, while levels increased rapidly when polyamines were added. We have used a series of reporters to examine the basis for the lack of RpoS in polyamine-deficient cells. The polyamine requirement was independent of small RNA-mediated positive regulation of RpoS translation. Mutations in rssB stabilize RpoS and significantly bypassed the polyamine deficit, suggesting that lack of polyamines might lead to rapid RpoS degradation. However, rates of degradation of mature RpoS were unaffected by polyamine availability. Codon optimization in rpoS partially relieved the polyamine dependence, suggesting a defect in RpoS translation in the absence of polyamines. Consistent with this, a hyperproofreading allele of ribosomal protein S12, encoded by rpsL, showed a decrease in RpoS levels, and this decrease was also suppressed by either codon optimization or blocking RpoS degradation. We suggest that rpoS codon usage leads it to be particularly sensitive to slowed translation, due to either lack of polyamines or hyperproofreading, leading to cotranslational degradation. We dedicate this study to Herb Tabor and his foundational work on polyamines, including the basis for this study.

Nanoparticle-Polymer Surface Functionalizations for Capacitive Energy Storage: Experimental Comparison to First Principles Simulations.

Dielectric capacitors present many advantages for large-scale energy storage, but they presently require higher energy density. We demonstrate novel high energy density polymer-nanoparticle composite capacitors utilizing thiol-ene click chemistry surface groups to bond the nanoparticles covalently to the polymer matrix. Interfacial effects in composites cannot be observed directly, and in our previous work, we examined the nanoparticle-polymer interface in silico. In this work, we experimentally examine the five surface functionalizations modeled previously, fabricating high energy density thin film capacitors to test our predictions. Results from this study, in conjunction with properties previously determined in silico, further improve the understanding of the role of surface functionalizations in composites prepared using click chemistry. The coating density of the surface functionalizations is shown to be a key factor in relating our computational results to experimental results. We show how using both coating density and our previous modeling in combination allows for prescreening of surface functionalizations for future composites, reducing experimental cost. We also demonstrate high energy density capacitors with ~20 J/cm3.

Physical Evidence of Oil Uptake and Toxicity Assessment of Amphiphilic Grafted Nanoparticles Used as Oil Dispersants.

Herein, we report the toxicity evaluation of a new prototype dispersant system, silicon dioxide nanoparticles (NPs) functionalized with (3-glycidoxypropyl)triethoxysilane (GPS) and grafted poly(ε-caprolactone)-block-poly[oligo(ethylene glycol)methyl methacrylate mono-methyl ether] (NP-PCL-POEGMA). This serves as a follow up of our previous study where grafted silicon dioxide NPs functionalized with GPS and grafted hyperbranched poly(glycidol) (NP-HPG) were evaluated for reducing the toxicity in embryo, juvenile, and adult fish populations. In this study, the NP-HPG sample is used as a baseline to compare against the new NP-PCL-POEGMA samples. The relative size was established for three NP-PCL-POEGMA samples via cryogenic transmission electron microscopy. A quantitative mortality study determined that these NPs are non-toxic to embryo populations. An ethoxyresorufin-O-deethylase assay was performed on these NP-PCL-POEGMA samples to test for reduced cytochrome P450 1A after the embryos were exposed to the water-accommodated fraction of crude oil. Overall, these NP-PCL-POEGMA NPs better protected the embryo populations than the previous NP-HPG sample (using a protein activity end point), showing a trend in the right direction for prototype dispersants to replace the commercially utilized Corexit.

A patient with lower extremity weakness after recent endovascular repair of an abdominal aortic aneurysm.

BACKGROUND: Thrombosis of an endovascular aortic repair (EVAR) is a devastating complication of a common surgical procedure that can lead to serious morbidity and mortality if not promptly recognized. This is the first case report of an EVAR graft thrombosis in the emergency medicine literature. CASE REPORT: We present a case of a patient with lower extremity paraplegia secondary to thrombosis of an EVAR graft who presented to the emergency room with acute stroke-like symptoms after a recent EVAR procedure. Endovascular repair of abdominal aortic aneurisms is becoming more frequent, and an increased number of patients with recent abdominal aortic aneurism repair by endovascular grafts will be evaluated by emergency physicians in the future. Emergency physicians should be aware that signs of limb ischemia, which may masquerade as acute ischemic stroke-like symptoms, is one of the more serious complications that can occur with abdominal aortic vascular grafts. Among patients with lower extremity neurological deficits in the recent setting of EVAR presenting to an emergency department, there should be a high degree of suspicion for EVAR graft thrombosis, which can be diagnosed via the gold standard of CT angiography or ultrasonography. Prompt vascular surgery consultation is essential to minimize permanent disability.

Leaf expansion in Phaseolus: transient auxin-induced growth increase.

Control of leaf expansion by auxin is not well understood. Evidence from short term exogenous applications and from treatment of excised tissues suggests auxin positively influences growth. Manipulations of endogenous leaf auxin content, however, suggests that, long-term, auxin suppresses leaf expansion. This study attempts to clarify the growth effects of auxin on unifoliate (primary) leaves of the common bean (Phaseolus vulgaris) by reexamining the response to auxin treatment of both excised leaf strips and attached leaves. Leaf strips, incubated in culture conditions that promoted steady elongation for up to 48 h, treated with 10 µM NAA responded with an initial surge of elongation growth complete within 10 hours followed by insensitivity. A range of NAA concentrations from 0.1 µM to 300 µM induced increased strip elongation after 24 hours and 48 hours. Increased elongation and epinastic curvature of leaf strips was found specific to active auxins. Expanding attached unifoliates treated once with aqueous auxin α-naphthalene acetic acid (NAA) at 1.0 mM showed both an initial surge in growth lasting 4-6 hours followed by growth inhibition sustained at least as long as 24 hours post treatment. Auxin-induced inhibition of leaf expansion was associated with smaller epidermal cell area. Together the results suggest increasing leaf auxin first increases growth then slows growth through inhibition of cell expansion. Excised leaf strips, retain only the initial increased growth response to auxin and not the subsequent growth inhibition, either as a consequence of wounding or of isolation from the plant.

Structural insight into the functional mechanism of Nep1/Emg1 N1-specific pseudouridine methyltransferase in ribosome biogenesis.

Nucleolar Essential Protein 1 (Nep1) is required for small subunit (SSU) ribosomal RNA (rRNA) maturation and is mutated in Bowen-Conradi Syndrome. Although yeast (Saccharomyces cerevisiae) Nep1 interacts with a consensus sequence found in three regions of SSU rRNA, the molecular details of the interaction are unknown. Nep1 is a SPOUT RNA methyltransferase, and can catalyze methylation at the N1 of pseudouridine. Nep1 is also involved in assembly of Rps19, an SSU ribosomal protein. Mutations in Nep1 that result in decreased methyl donor binding do not result in lethality, suggesting that enzymatic activity may not be required for function, and RNA binding may play a more important role. To study these interactions, the crystal structures of the scNep1 dimer and its complexes with RNA were determined. The results demonstrate that Nep1 recognizes its RNA site via base-specific interactions and stabilizes a stem-loop in the bound RNA. Furthermore, the RNA structure observed contradicts the predicted structures of the Nep1-binding sites within mature rRNA, suggesting that the Nep1 changes rRNA structure upon binding. Finally, a uridine base is bound in the active site of Nep1, positioned for a methyltransfer at the C5 position, supporting its role as an N1-specific pseudouridine methyltransferase.

The Effect of Drawing Microbiology Concepts on Short-Term Retention Before and After Interrupted Learning.

Introduction: Throughout the preclinical education curriculum, medical students learn numerous concepts that must be retained and added to over time. Previous studies have shown that utilizing drawing leads to improved retention of concepts. However, limited studies have investigated the use of drawing at the medical school level. The goal of this study was to utilize mechanism-based drawing aimed at presenting conceptual material rather than strict memorization before and after interrupted learning. Methods: Participants were randomly assigned to a drawing group or a text-only group and both groups received text #1 that explained a microbiology concept. The groups were instructed to read the text, but only the drawing group received a drawing prompt. The groups then completed post-test #1. During part #2 of the study, the groups were instructed to read text #2 with no drawing prompt. The two groups were instructed to complete post-test #2 which covered topics from text #1 and #2. p<0.05 was considered significant. Results: The drawing group performed significantly better on post-test #1 compared to the text-only group. There were no significant differences on overall performance on post-test #2. However, the drawing group performed significantly better on questions related to the material covered in text #1 on post-test #2. Conclusion: Results presented here demonstrate that students who draw perform significantly better when assessed on complex microbiology concepts, even after interrupted by the introduction of an unrelated concept. A future study should investigate the effectiveness of drawing after interruption by learning on long-term retention and performance.

Video Documentation as a Measure of Written Documentation Accuracy in Emergency Medical Service Field Intubations.

Introduction: Quality improvement (QI) is a major focus of all departments and fields of health care, including emergency medical services. The chaotic and rapidly evolving atmosphere in which paramedics must practice can lead to inconsistency between what is documented and the actual events. This leads to difficulty when trying to evaluate the practitioners and when implementing a QI program. In this study, we evaluated the prevalence of discrepancy between the video and written record for Rapid Sequence Intubation (RSI) performed in the field as a demonstration of the utility of video documentation in QI. Methods: We used a systematic retrospective chart review to compare written with video documentation in 100 consecutive prehospital RSI encounters in a single EMS agency. Results: Of the patient care records (PCRs), only 6% matched the video record for all quality measures tracked. The largest reason for the discrepancy was in the time required to intubate (58%) whether LEMON was evaluated (42%), total number of intubation attempts (36%), first attempt success (24%), BVM used (18%), and whether an airway introducer device was used (12%). Conclusion: Written documentation is inaccurate compared to video documentation when used as a quality improvement process for EMS prehospital RSI encounters.

Hypermethylation of a cluster of Krüppel-type zinc finger protein genes on chromosome 19q13 in oropharyngeal squamous cell carcinoma.

Identification of epigenetically affected genes has become an important tool for understanding both normal and aberrant gene expression in cancer. Here we report a whole-genome analysis of DNA methylation profiles in fresh-frozen oropharyngeal squamous cell carcinoma (OPSCC) tissues and normal mucosa samples using microarray technology with patient genomic DNA. We initially compared whole-genome patterns of DNA methylation among 24 OPSCC primary tumors and 24 matched normal mucosal samples. From a survey of 27,578 CpG dinucleotide loci spanning more than 14,000 genes, we identified 958 CpG loci in which measurements of DNA methylation were altered in the primary tumors relative to the normal mucosal samples. These alterations were validated in an independent set of 21 OPSCC patients. A survey of these loci by chromosomal location revealed an abnormally high number of differentially methylated loci on chromosome 19. Many of the loci on chromosome 19 are associated with genes belonging to the Krüppel-type zinc finger protein genes. Hypermethylation was accompanied by a significant decrease in expression of these genes in OPSCC primary tumors relative to adjacent mucosa. This study reports the epigenetic silencing of Krüppel-type zinc finger protein genes on chromosome 19q13 in oropharyngeal cancer. The aberrant methylation of these genes represents a new avenue of exploration for pathways affected in this disease.

Mechanisms of erythropoiesis inhibition by malarial pigment and malaria-induced proinflammatory mediators in an in vitro model.

One of the commonest complications of Plasmodium falciparum malaria is the development of severe malarial anemia (SMA), which is, at least in part, due to malaria-induced suppression of erythropoiesis. Factors associated with suppression of erythropoiesis and development of SMA include accumulation of malarial pigment (hemozoin, PfHz) in bone marrow and altered production of inflammatory mediators, such as tumor necrosis factor (TNF)-α, and nitric oxide (NO). However, studies investigating the specific mechanisms responsible for inhibition of red blood cell development have been hampered by difficulties in obtaining bone marrow aspirates from infants and young children, and the lack of reliable models for examining erythroid development. As such, an in vitro model of erythropoiesis was developed using CD34+ stem cells derived from peripheral blood to examine the effects of PfHz, PfHz-stimulated peripheral blood mononuclear cell (PBMC)-conditioned media (CM-PfHz), TNF-α, and NO on erythroid cell development. PfHz only slightly suppressed erythroid cell proliferation and maturation marked by decreased expression of glycophorin A (GPA). On the other hand, CM-PfHz, TNF-α, and NO significantly inhibited erythroid cell proliferation. Furthermore, decreased proliferation in cells treated with CM-PfHz and NO was accompanied by increased apoptosis of erythropoietin-stimulated CD34+ cells. In addition, NO significantly inhibited erythroid cell maturation, whereas TNF-α did not appear to be detrimental to maturation. Collectively, our results demonstrate that PfHz suppresses erythropoiesis by acting both directly on erythroid cells, and indirectly via inflammatory mediators produced from PfHz-stimulated PBMC, including TNF-α and NO.

Photolysis of (3-methyl-2H-azirin-2-yl)-phenylmethanone: direct detection of a triplet vinylnitrene intermediate.

The photoreactivity of (3-methyl-2H-azirin-2-yl)-phenylmethanone, 1, is wavelength-dependent (Singh et al. J. Am. Chem. Soc. 1972, 94, 1199-1206). Irradiation at short wavelengths yields 2P, whereas longer wavelengths produce 3P. Laser flash photolysis of 1 in acetonitrile using a 355 nm laser forms its triplet ketone (T(1K), broad absorption with λ(max) ~ 390-410 nm, τ ~ 90 ns), which cleaves and yields triplet vinylnitrene 3 (broad absorption with λ(max) ~ 380-400 nm, τ = 2 µs). Calculations (B3LYP/6-31+G(d)) reveal that T(1K) of 1 is located 67 kcal/mol above its ground state (S(0)) and has a long C-N bond (1.58 Å), and the calculated transition state to form 3 is only 1 kcal/mol higher in energy than T(1K) of 1. The calculations show that 3 has significant 1,3-carbon iminyl biradical character, which explains why 3 reacts efficiently with oxygen and decays by intersystem crossing to the singlet surface. Photolysis of 1 in argon matrixes at 14 K produced ketene imine 7, which presumably is formed from 3 intersystem crossing to 7. In comparison, photolysis of 1 in methanol with a 266 nm laser produces mainly ylide 2 (λ(max) ~ 380 nm, τ ~ 6 µs, acetonitrile), which decays to form 2P. Ylide 2 is formed via singlet reactivity of 1, and calculations show that the first singlet excited state of the azirine chromophore (S(1A)) is located 113 kcal/mol above its S(0) and that the singlet excited state of the ketone (S(1K)) is 85 kcal/mol. Furthermore, the transition state for cleaving the C-C bond in 1 to form 2 is located 49 kcal/mol above the S(0) of 1. Thus, we theorize that internal conversion of S(1A) to a vibrationally hot S(0) of 1 forms 2, whereas intersystem crossing from S(1K) to T(1K) results in 3.

A novel functional variant in the stem cell growth factor promoter protects against severe malarial anemia.

Plasmodium falciparum malaria is a leading global cause of infectious disease burden. In areas in which P. falciparum transmission is holoendemic, such as western Kenya, severe malarial anemia (SMA) results in high rates of pediatric morbidity and mortality. Although the pathophysiological basis of SMA is multifactorial, we recently discovered that suppression of unexplored hematopoietic growth factors that promote erythroid and myeloid colony development, such as stem cell growth factor (SCGF) (C-type lectin domain family member 11A [CLEC11A]), was associated with enhanced development of SMA and reduced erythropoietic responses. To extend these investigations, the relationships between a novel SCGF promoter variant (-539C/T, rs7246355), SMA (hemoglobin [Hb] < 6.0 g/dl), and reduced erythropoietic responses (reticulocyte production index [RPI], <2.0) were investigated with Kenyan children (n = 486) with falciparum malaria from western Kenya. Circulating SCGF was positively correlated with hemoglobin levels (r = 0.251; P = 0.022) and the reticulocyte production index (RPI) (r = 0.268; P = 0.025). Children with SMA also had lower SCGF levels than those in the non-SMA group (P = 0.005). Multivariate logistic regression analyses controlling for covariates demonstrated that individuals with the homologous T allele were protected against SMA (odds ratio, 0.57; 95% confidence interval [95% CI] 0.34 to 0.94; P = 0.027) relative to CC (wild-type) carriers. Carriers of the TT genotype also had higher SCGF levels in circulation (P = 0.018) and in peripheral blood mononuclear cell culture supernatants (P = 0.041), as well as an elevated RPI (P = 0.005) relative to individuals with the CC genotype. The results presented here demonstrate that homozygous T at -539 in the SCGF promoter is associated with elevated SCGF production, enhanced erythropoiesis, and protection against the development of SMA in children with falciparum malaria.

Inflammatory biomarkers and decline in kidney function in the elderly: the Cardiovascular Health Study.

BACKGROUND: Cross-sectional studies have demonstrated a consistent and linear association between circulating inflammatory markers and kidney function. The objective of this study was to determine whether elevated markers of inflammation are independently associated with longitudinal kidney function decline. METHODS: This study included 4128 subjects from the Cardiovascular Health Study. Cystatin C was measured at baseline, 3 years later and 7 years later; eligible subjects had at least two measures. Cystatin C-based estimated glomerular filtration rate (eGFR(cysC)) was estimated, and rapid kidney function decline was defined as an annual loss of eGFR(cysC) >3 mL/min/1.73 m(2). Predictors included ten inflammatory and procoagulant biomarkers: C-reactive protein, interleukin-6, intercellular adhesion molecule-1, white blood cell count, fibrinogen, factor VII, factor VIII, D-dimer, plasmin-antiplasmin complex and serum albumin. RESULTS: During the study, 1059 subjects (26%) had a rapid decline in kidney function. In contrast to the other nine inflammatory or procoagulant biomarkers, serum albumin had a consistent and inverse association with rapid kidney function decline [final adjusted logistic regression model: 1.14-fold increased odds (95% CI 1.06-1.23) of rapid decline per standard deviation lower albumin]. The lowest quartile of albumin had an odds ratio of 1.55 (95% CI 1.23-1.96) for rapid decline compared with the highest quartile. These associations persisted after adjusting the albumin models for CRP, IL-6 and fibrinogen. CONCLUSIONS: In contrast to nine other inflammatory and procoagulant markers, only lower baseline levels of serum albumin were consistently associated with a rapid decline in kidney function, as measured by cystatin C-based eGFR.

Toxicity assessment of a novel oil dispersant based on silica nanoparticles using Fathead minnow.

Oil spill accidents are a major concern for aquatic organisms. In recent history, the Deepwater Horizon blowout spilled 500 million liters of crude oil into the Gulf of Mexico. Corexit 9500A was used to disperse the oil since it was the method approved at that time, despite safety concerns about its use. A better solution is necessary for dispersing oil from spills that reduces the toxicity to exposed aquatic organisms. To address this challenge, novel engineered nanoparticles were designed using silica cores grafted with hyperbranched poly(glycidol) branches. Because the silica core and polymers are known to be biocompatible, we hypothesized that these particles are nontoxic to fathead minnows (Pimephales promelas) and would decrease their exposure to oil polyaromatic hydrocarbons. Fathead minnow embryos, juveniles and adult stages were exposed to the particles alone or in combination with a water-accommodated fraction of oil. Acute toxicity of nanoparticles to fish was tested by measuring mortality. Sub-lethal effects were also measured including gene expression of cytochrome P450 1a (cyp1a) mRNA and heart rate in embryos. In addition, a mixture of particles plus the water-accommodated fraction was directly introduced to adult female fathead minnows by gavage. Three different nanoparticle concentrations were used (2, 10, and 50 mg/L) in either artificial fresh water or the water-accommodated fraction of the oil. In addition, nanoparticle-free controls were carried out in the two solutions. No significant mortality was observed for any age group or nanoparticle concentration, suggesting the safety of the nanoparticles. In the presence of the water-accommodated fraction alone, juvenile and adult fathead minnows responded by increasing expression of cyp1a. The addition of nanoparticles to the water-accommodated fraction reduced cyp1a gene expression in treatments. Heart rate was also restored to normal parameters in embryos co-exposed to nanoparticles and to the water-accommodated fraction. Measurement of polyaromatic hydrocarbons confirmed their presence in the tested solutions and the reduction of available PAH in WAF treated with the nanoparticles. Our findings suggest the engineered nanoparticles may be protecting the fish by sequestering polyaromatic hydrocarbons from oil, measured indirectly by the induction of cypa1 mRNAs. Furthermore, chemical analysis showed a reduction in PAH content in the water accommodated fraction with the presence of nanoparticles.

Suppression of a novel hematopoietic mediator in children with severe malarial anemia.

In areas of holoendemic Plasmodium falciparum transmission, severe malarial anemia (SMA) is a leading cause of pediatric morbidity and mortality. Although many soluble mediators regulate erythropoiesis, it is unclear how these factors contribute to development of SMA. Investigation of novel genes dysregulated in response to malarial pigment (hemozoin [PfHz]) revealed that stem cell growth factor (SCGF; also called C-type lectin domain family member 11A [CLEC11A]), a hematopoietic growth factor important for development of erythroid and myeloid progenitors, was one of the most differentially expressed genes. Additional experiments with cultured peripheral blood mononuclear cells (PBMCs) demonstrated that PfHz decreased SCGF/CLEC11A transcriptional expression in a time-dependent manner. Circulating SCGF levels were then determined for Kenyan children (n = 90; aged 3 to 36 months) presenting at a rural hospital with various severities of malarial anemia. SCGF levels in circulation (P = 0.001) and in cultured PBMCs (P = 0.004) were suppressed in children with SMA. Circulating SCGF also correlated positively with hemoglobin levels (r = 0.241; P = 0.022) and the reticulocyte production index (RPI) (r = 0.280; P = 0.029). In addition, SCGF was decreased in children with reduced erythropoiesis (RPI of <2) (P < 0.001) and in children with elevated levels of naturally acquired monocytic PfHz (P = 0.019). Thus, phagocytosis of PfHz promotes a decrease in SCGF gene products, which may contribute to reduced erythropoiesis in children with SMA.

Absolute requirement for polyamines for growth of Escherichia coli mutants (mnmE/G) defective in modification of the wobble anticodon of transfer-RNA.

The genes mnmE and mnmG are responsible for the modification of uridine 34, 'the wobble position' of many aminoacyl-tRNAs. Deletion of these genes affects the strength of the codon-anticodon interactions of the aminoacyl-tRNAs with the mRNAs and the ribosomes. However, deletion of these genes does not usually have a significant effect on the growth rate of the standard Escherichia coli strains. In contrast, we have found that if the host E. coli strain is deficient in the synthesis of polyamines, deletion of the mnmE or mnmG gene results in complete inhibition of growth unless the medium contains polyamines. The finding of an absolute requirement for polyamines in our current work will be significant in studies on polyamine function, in studies on the function of the mnmE/G genes, and in studies on the role of aminoacyl-tRNAs in protein biosynthesis.

Association of kidney function with inflammatory and procoagulant markers in a diverse cohort: a cross-sectional analysis from the Multi-Ethnic Study of Atherosclerosis (MESA).

BACKGROUND: Prior studies using creatinine-based estimated glomerular filtration rate (eGFR) have found limited associations between kidney function and markers of inflammation. Using eGFR and cystatin C, a novel marker of kidney function, the authors investigated the association of kidney function with multiple biomarkers in a diverse cohort. METHODS: The Multi-Ethnic Study of Atherosclerosis consists of 6,814 participants of white, African-American, Hispanic, and Chinese descent, enrolled from 2000-2002 from six U.S. communities. Measurements at the enrollment visit included serum creatinine, cystatin C, and six inflammatory and procoagulant biomarkers. Creatinine-based eGFR was estimated using the four-variable Modification of Diet in Renal Disease equation, and chronic kidney disease was defined by an eGFR < 60 mL/min/1.73 m2. RESULTS: Adjusted partial correlations between cystatin C and all biomarkers were statistically significant: C-reactive protein (r = 0.08), interleukin-6 (r = 0.16), tumor necrosis factor-alpha soluble receptor 1 (TNF-alphaR1; r = 0.75), intercellular adhesion molecule-1 (r = 0.21), fibrinogen (r = 0.14), and factor VIII (r = 0.11; two-sided p < 0.01 for all). In participants without chronic kidney disease, higher creatinine-based eGFR was associated only with higher TNF-alphaR1 levels. CONCLUSION: In a cohort characterized by ethnic diversity, cystatin C was directly associated with multiple procoagulant and inflammatory markers. Creatinine-based eGFR had similar associations with these biomarkers among subjects with chronic kidney disease.

Tropomodulin's Actin-Binding Abilities Are Required to Modulate Dendrite Development.

There are many unanswered questions about the roles of the actin pointed end capping and actin nucleation by tropomodulins (Tmod) in regulating neural morphology. Previous studies indicate that Tmod1 and Tmod2 regulate morphology of the dendritic arbor and spines. Tmod3, which is expressed in the brain, had only a minor influence on morphology. Although these studies established a defined role of Tmod in regulating dendritic and synaptic morphology, the mechanisms by which Tmods exert these effects are unknown. Here, we overexpressed a series of mutated forms of Tmod1 and Tmod2 with disrupted actin-binding sites in hippocampal neurons and found that Tmod1 and Tmod2 require both of their actin-binding sites to regulate dendritic morphology and dendritic spine shape. Proximity ligation assays (PLAs) indicate that these mutations impact the interaction of Tmod1 and Tmod2 with tropomyosins Tpm3.1 and Tpm3.2. This impact on Tmod/Tpm interaction may contribute to the morphological changes observed. Finally, we use molecular dynamics simulations (MDS) to characterize the structural changes, caused by mutations in the C-terminal helix of the leucine-rich repeat (LRR) domain of Tmod1 and Tmod2 alone and when bound onto actin monomers. Our results expand our understanding of how neurons utilize the different Tmod isoforms in development.

Higher production of peripheral blood macrophage migration inhibitory factor in healthy children with a history of mild malaria relative to children with a history of severe malaria.

Plasmodium falciparum malaria is one of the leading causes of childhood morbidity and mortality in sub-Saharan Africa. The host immune response to P. falciparum is a critical determinant of malarial pathogenesis and disease outcomes. Macrophage migration inhibitory factor (MIF) is a central regulator of innate immune responses to bacterial and parasitic infections. Our recent investigations demonstrated that peripheral blood MIF production was suppressed in children with severe malaria. Because examination of MIF production in children with active disease does not account for the inherent ability of the host to generate MIF, basal circulating MIF and peripheral blood mononuclear cell (PBMC) MIF transcript levels were determined in healthy children with a history of either mild or severe malaria. Children with prior mild malaria had higher plasma MIF levels and PBMC MIF transcripts than children with an identical number of previous episodes of severe malaria. These results suggest that increased basal MIF production may be important in generating immune responses that protect against the development of severe malaria.

Characterization of transforming growth factors beta1 and 2 in ferrets (Mustela putorius furo).

Unwanted scar tissue after surgical procedures remains a central problem in medicine. Nowhere is this problem more evident than within the pediatric airway, where excess scarring, termed subglottic stenosis, can compromise breathing. Recent advances in molecular biology have focused on ways to decrease scar formation through understanding of the wound repair process. Transforming growth factor beta (TFGbeta) plays a central role in this pathway. Ferrets serve as an ideal model for the pediatric airway, and reproduction of subglottic stenosis in ferrets is possible. However, ferret cytokine profiles have not been established. In this study, we characterized the presence and nucleotide sequence of the TGFbeta1 and 2 genes in ferrets by using total RNA isolated from airways. Amino acid sequence homology between human and ferret was determined to be 96.6% for TGFbeta1 and 99.3% for TGFbeta2. Given the nearly total homology between TGFbetas of ferret and human origin, the ferret may serve as an ideal model for future molecular studies.