The microtubule-associated protein tau is abnormally hyperphosphorylated in the brains of individuals with Alzheimer disease and other tauopathies, and is believed to play a critical role in the pathogenesis of these diseases. While the mechanisms leading to abnormal tau phosphorylation remain elusive, the recent demonstration of reversible tau phosphorylation during hibernation provides an ideal physiological model to study this critical process in vivo. In this study, arctic ground squirrels (AGS) during hibernation were used to study mechanisms related to tau hyperphosphorylation. Our data demonstrate that tau is hyperphosphorylated at all six sites (S199, T205, S214, S262, S396, and S404) examined in hibernating AGS. Interestingly, only three of these sites (S199, S262, and S404) are dephosphorylated in aroused animals, suggesting a reversible phosphorylation at selective sites. Summer-active AGS demonstrated the lowest tau phosphorylation at all these sites. To explore the mechanisms underlying increased tau phosphorylation during hibernation, the expression level and enzyme activity of various potential tau kinases and protein phosphatases were examined. The kinetic analysis of enzyme activity at different temperatures revealed differential changes in enzyme activity with temperature decline. Specifically, increased protein kinase A activity, decreased protein phosphatase 2A activity, as well as substantial contribution from glycogen synthase kinase-3β, likely play a key role in increased tau phosphorylation during hibernation in AGS.
hibernation; protein kinase A; protein phosphatase 2A; reversible phosphorylation; tau
Hibernation is a natural model of neuroprotection and adult synaptic plasticity. NMDA receptors (NMDAR), which play key roles in excitotoxicity and synaptic plasticity, have not been characterized in a hibernating species. Tolerance to excitotoxicity and cognitive enhancement in Arctic ground squirrels (AGS, Spermophilus parryii) suggests that NMDAR expression may decrease in hibernation and increase upon arousal. NMDAR consist of at least one NMDAR1 (NR1) subunit, which is required for receptor function. Localization of NR1 reflects localization of the majority, if not all, NMDAR complexes. The purpose of this study, therefore, was to characterize the distribution of NR1 subunits in AGS central nervous system using immunohistochemistry. In addition, we compare NR1 expression in hippocampus of hibernating AGS (hAGS) and inter-bout euthermic AGS (ibeAGS) and assess changes in cell somata size using NR1 stained sections in three hippocampal sub-regions (CA1, CA3, and dentate gyrus). For the first time, we report that immunoreactivity of anti-NR1 is widely distributed throughout the central nervous system in AGS and is similar to other species. No differences exist in the expression and distribution of NR1 in hAGS and ibeAGS. However, we report a significant decrease in size of hippocampal CA1 and dentate gyrus NR1-expressing neuronal somata during hibernation torpor.
NMDAR1; Immunohistochemistry; Hibernation; Neuronal somata size; Hippocampus
The capability of continuously sampling the extracellular fluid opens up a wide range of applications of microdialysis in biological, pharmaceutical, and clinical studies. Existing microdialysis, however, faces challenges in sampling analytes with fast clearance and limited diffusivity because sampling resolution is limited by device size. Size reduction in probes and interconnected cannulae is a promising solution to improve temporal and spatial resolution. But the back pressure produced by resistance to laminar flows will be magnified in smaller channels, raising a concern as to whether it is feasible to operate continuous perfusion for miniaturized microdialysis. We demonstrate that a 10-fold smaller channel will exhibit 100-fold larger back pressure in response to the increase in the flow rate to maintain the relative recovery. In order to overcome the foreseen back pressure issue, this paper discusses a new concept using discrete droplets instead of continuous flows to operate dialysis in a miniaturized probe. This conceptual design is referred to as droplet-based digital microdialysis, in which droplets are produced, controlled and advanced within microchannels at a rate that in theory should allow for analytes to equilibrate with the extracellular fluid under no flow conditions. Expecting that a digital droplet design will entirely eliminate back pressure by introducing air between droplets, we numerically compare the equilibration kinematics of droplets to that of continuous flow. Results suggest equilibration of low molecular weight analytes between intermittently stationary droplets and the extracellular fluid in a few seconds. Considerations in design, prototyping, calibration and quantification, and the integration with other devices are suggested.
Droplet; Microdialysis; Quantitative; Back pressure; Miniaturization
Heterothermic mammals such as ground squirrels tolerate ischemia and N-methyl-D-aspartate (NMDA) better than homeothermic mammals such as rats both in vivo and in vitro, and this tolerance is enhanced in the hibernating state. However, the cellular mechanisms underlying this tolerance remain unclear. NMDA receptors (NMDAR) play a key role in excitotoxicity. The purpose of the current study was therefore to test the hypothesis that NMDAR are down-regulated in hibernating Arctic ground squirrels (hAGS; Spermophilus parryii). To address this hypothesis, we used Western blot analysis to investigate NMDAR phosphorylation, an activator of NMDAR function, and internalization in naïve hippocampal tissue from hAGS, interbout euthermic AGS (ibeAGS), and rats. Furthermore, we used fura-2 calcium imaging to examine NMDAR function in cultured hippocampal slices from hAGS, ibeAGS, and rats. We report that phosphorylation of the NMDAR1 (NR1) subunit is decreased in hippocampal tissue from hAGS and that the NMDAR component of Glu-induced increase in [Ca2+]i is decreased in hippocampal slices from hAGS. Moreover, the fraction of NR1 in the functional membrane pool in AGS is less than that in rats.
hibernation; hippocampal slices; excitotoxicity; stroke; fura-2
Very low-calorie diets (VLCDs) are an effective means by which to induce clinically significant weight loss. However, their acceptance by health care practitioners and the public is generally lower than that for other nonsurgical weight loss methods. Whilst there is currently little evidence to suggest they have any detrimental effect on hepatic and renal health, data assessing these factors remain limited. We carried out a systematic review of the literature on randomized controlled trials that had a VLCD component and that reported outcomes for hepatic and renal health, published between January 1980 and December 2012. Cochrane criteria were followed, and eight out of 196 potential articles met the inclusion criteria. A total of 548 participants were recruited across the eight studies. All eight studies reported significant weight loss following the VLCD. Changes in hepatic and renal outcomes were variable but generally led to either no change or improvements in either of these. Due to the heterogeneity in the quality and methodology of the studies included, the effect of VLCDs on hepatic and renal outcomes remains unclear at this stage. Further standardized research is therefore required to fully assess the impact of VLCDs on these outcome measures, to better guide clinical practice.
obesity; liver; kidney; weight loss; health
Diffuse intrinsic pontine glioma (DIPG) is an incurable tumor that arises in the brainstem of children. To date there is not a single approved drug to effectively treat these tumors and thus novel therapies are desperately needed. Recent studies suggest that a significant fraction of these tumors contain alterations in cell cycle regulatory genes including amplification of the D-type cyclins and CDK4/6, and less commonly, loss of Ink4a-ARF leading to aberrant cell proliferation. In this study, we evaluated the therapeutic approach of targeting the cyclin-CDK-Retinoblastoma (Rb) pathway in a genetically engineered PDGF-B-driven brainstem glioma (BSG) mouse model. We found that PD-0332991 (PD), a CDK4/6 inhibitor, induces cell-cycle arrest in our PDGF-B; Ink4a-ARF deficient model both in vitro and in vivo. By contrast, the PDGF-B; p53 deficient model was mostly resistant to treatment with PD. We noted that a 7-day treatment course with PD significantly prolonged survival by 12% in the PDGF-B; Ink4a-ARF deficient BSG model. Furthermore, a single dose of 10 Gy radiation therapy (RT) followed by 7 days of treatment with PD increased the survival by 19% in comparison to RT alone. These findings provide the rationale for evaluating PD in children with Ink4a-ARF deficient gliomas.
A recent meta-analysis of 103 studies Burt (Clinical Psychology Review, 29:163–178, 2009a) highlighted the presence of etiological distinctions between aggressive (AGG) and non-aggressive rule-breaking (RB) dimensions of antisocial behavior, such that AGG was more heritable than was RB, whereas RB was more influenced by the shared environment. Unfortunately, behavioral genetic research on antisocial behavior to date (and thus, the research upon which the meta-analysis was based) has relied almost exclusively on the classical twin model. This reliance is problematic, as the strict assumptions that undergird this model (e.g., shared environmental and dominant genetic influences are not present simultaneously; there is no assortative mating) can have significant consequences on heritability estimates when they are violated. The nuclear twin family model, by contrast, allows researchers to relax and statistically evaluate many of the assumptions of the classical twin design by incorporating parental self-report data along with the more standard twin data. The goal of the current study was thus to evaluate whether prior findings of etiological distinctions between AGG and RB persisted when using the nuclear twin family model. We examined a sample of 312 child twin families from the Michigan State University Twin Registry. Results strongly supported prior findings of etiological distinctions between AGG and RB, such that broad genetic influences were observed to be particularly important to AGG whereas shared environmental influences contributed only to RB. Nevertheless, the current findings also implied that additive genetic influences on antisocial behavior may be overestimated when using the classical twin design.
Antisocial behavior; Aggression; Rule-breaking; Nuclear twin family model
Endocrine disrupting chemicals (EDCs) cause physiological abnormalities and population decline in fishes. However, few studies have linked environmental EDC exposures with responses at multiple tiers of the biological hierarchy, including population-level effects. To this end, we undertook a four-tiered investigation in the impacted San Francisco Bay estuary with the Mississippi silverside (Menidia audens), a small pelagic fish. This approach demonstrated links between different EDC sources and fish responses at different levels of biological organization. First we determined that water from a study site primarily impacted by ranch run-off had only estrogenic activity in vitro, while water sampled from a site receiving a combination of urban, limited ranch run-off, and treated wastewater effluent had both estrogenic and androgenic activity. Secondly, at the molecular level we found that fish had higher mRNA levels for estrogen-responsive genes at the site where only estrogenic activity was detected but relatively lower expression levels where both estrogenic and androgenic EDCs were detected. Thirdly, at the organism level, males at the site exposed to both estrogens and androgens had significantly lower mean gonadal somatic indices, significantly higher incidence of severe testicular necrosis and altered somatic growth relative to the site where only estrogens were detected. Finally, at the population level, the sex ratio was significantly skewed towards males at the site with measured androgenic and estrogenic activity. Our results suggest that mixtures of androgenic and estrogenic EDCs have antagonistic and potentially additive effects depending on the biological scale being assessed, and that mixtures containing androgens and estrogens may produce unexpected effects. In summary, evaluating EDC response at multiple tiers is necessary to determine the source of disruption (lowest scale, i.e. cell line) and what the ecological impact will be (largest scale, i.e. sex ratio).
The alpha2 adrenergic receptor (α2-AR) antagonist yohimbine is a widely used tool for the study of anxiogenesis and stress-induced drug-seeking behavior. We previously demonstrated that yohimbine paradoxically depresses excitatory transmission in the bed nucleus of the stria terminalis (BNST), a region critical to the integration of stress and reward pathways, and produces an impairment of extinction of cocaine-conditioned place preference (cocaine-CPP) independent of α2-AR signaling. Recent studies show yohimbine-induced drug-seeking behavior is attenuated by orexin receptor 1 (OX1R) antagonists. Moreover, yohimbine-induced cocaine-seeking behavior is BNST-dependent. Here, we investigated yohimbine-orexin interactions. Our results demonstrate yohimbine-induced depression of excitatory transmission in the BNST is unaffected by alpha1-AR and corticotropin-releasing factor receptor-1 (CRFR1) antagonists, but is (1) blocked by OxR antagonists and (2) absent in brain slices from orexin knockout mice. Although the actions of yohimbine were not mimicked by the norepinephrine transporter blocker reboxetine, they were by exogenously applied orexin A. We find that, as with yohimbine, orexin A depression of excitatory transmission in BNST is OX1R–dependent. Finally, we find these ex vivo effects are paralleled in vivo, as yohimbine-induced impairment of cocaine-CPP extinction is blocked by a systemically administered OX1R antagonist. These data highlight a new mechanism for orexin on excitatory anxiety circuits and demonstrate that some of the actions of yohimbine may be directly dependent upon orexin signaling and independent of norepinephrine and CRF in the BNST.
norepinephrine; orexin; plasticity; reward; stress; yohimbine; addiction & substance abuse; plasticity; mood/anxiety/stress disorders; neuropharmacology; orexin; bnst; yohimbine; reward; norepinephrine
Hibernation is an adaptation to overcome periods of resource limitation often associated with extreme climatic conditions. The hibernation season consists of prolonged bouts of torpor that are interrupted by brief interbout arousals. Physiological mechanisms regulating spontaneous arousals are poorly understood, but may be related to a need for gluconeogenesis or elimination of metabolic wastes. Glutamate is derived from glutamine through the glutamate-glutamine cycle and from glucose via the pyruvate carboxylase pathway when nitrogen balance favors formation of glutamine. The present study tests the hypothesis that activation of NMDA type glutamate receptors (NMDAR) maintains torpor in arctic ground squirrel (AGS; Urocitellus parryii).Administration of NMDAR antagonists MK-801 (5mg/kg,ip) that crosses blood-brain barrier and AP5 (5mg/kg,ip) that does not cross the blood brain barrier induced arousal in AGS. Central administration of MK-801 (0.2, 2, 20 or 200 μg; icv) to hibernating AGS failed to induce arousal. Results suggest that activation of NMDAR at a peripheral or circumventricular site is necessary to maintain prolonged torpor and that a decrease in glutamate at these sites may contribute to spontaneous arousal in AGS.
Hibernation; arctic ground squirrel; glutamate; NMDAR; MK-801; circumventricular organ
A recent meta-analysis (Burt, 2009) indicated that shared environmental influences (C) do not contribute to Attention-Deficit/Hyperactivity Disorder (ADHD). Unfortunately, the meta-analysis relied almost exclusively on classical twin studies. Although useful in many ways, some of the assumptions of the classical twin model (e.g., dominant genetic and shared environmental influences do not simultaneously influence the phenotype) can artifactually decrease estimates of C. There is thus a need to confirm that dominant genetic influences are not suppressing estimates of C on ADHD. The current study sought to do just this via the use of a nuclear twin family model, which allows researchers to simultaneously model and estimate dominant genetic and shared environmental influences. We examined two independent samples of child twins: 312 pairs from the Michigan State University Twin Registry (MSUTR) and 854 pairs from the PrEschool Twin Study in Sweden (PETSS). Shared environmental influences were found to be statistically indistinguishable from zero and accounted for less than 5% of the variance. We conclude that the presence of dominant genetic influences does not account for the absence of C on ADHD.
ADHD; nuclear twin family model; shared environment; genetic influences
Motor dysfunctions of Parkinson Disease (PD) are due to the progressive loss of midbrain nigrostriatal dopamine (NSDA) neurons. Evidence suggests a role for cannabinoid receptors in the neurodegeneration of these neurons following neurotoxicant-induced injury. This work evaluates NSDA neurons in CB1/CB2 knockout (KO) mice and tests the hypothesis that CB1/CB2 KO mice are more susceptible to neurotoxicant exposure. NSDA neuronal indices were assessed using unbiased stereological cell counting, high pressure liquid chromatography coupled with electrochemical detection or mass spectrometry, and Western blot. Results reveal that CB1 and CB2 cannabinoid receptor signaling is not necessary for the maintenance of a normally functioning NSDA neuronal system. Mice lacking CB1 and CB2 receptors were found to be equally susceptible to the neurotoxicant 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). These studies support the use of CB1/CB2 KO mice for investigating the cannabinoid receptor-mediated regulation of the NSDA neuronal system in models of PD.
MPTP; CB1 receptor; CB2 receptor; nigrostriatal
The majority of blunt renal trauma is a consequence of motor vehicle collisions and falls. Prior publications based on urban series have shown that significant renal injuries are almost always accompanied by gross hematuria alone or microscopic hematuria with concomitant hypotension. We present a series of blunt renal trauma sustained during recreational pursuits, and describe the mechanisms, injury patterns and management.
Materials and Methods
Database review from 1996 to 2009 identified 145 renal injuries. Children younger than age 16 years, and trauma involving licensable motor vehicles, penetrating injuries and work related injuries were excluded from analysis. Grade, hematuria, hypotension, age, gender, laterality, mechanism, management, injury severity score and associated injuries were recorded.
We identified 106 patients meeting the criteria and 85% of the injuries were snow sport related. Age range was 16 to 76 years and 92.5% of patients were male. There were 39 grade 1 injuries, 30 grade 2, 22 grade 3, 12 grade 4 and 3 grade 5 injuries. Gross hematuria was present in 56.7%, 77.2% and 83.3% of grade 2, grade 3 and grade 4 injuries, respectively. None of the patients with grade 2 or greater injuries and microscopic hematuria had hypotension except 1 grade 5 pedicle injury. The nephrectomy and renorrhaphy rate for grade 1 to grade 4 injuries was 0%.
Compared to urban series of blunt renal trauma, recreationally acquired injuries appear to follow different patterns, including a paucity of associated injuries or hypotension. If imaging were limited to the presence of gross hematuria, or microscopic hematuria with hypotension, 23% of grade 2 to grade 4 injuries would be missed. Men are at higher risk than women. However, operative intervention is rarely helpful.
kidney; multiple trauma; retrospective studies; wounds; nonpenetrating; injury severity score
Patients hospitalized for psychiatric reasons exhibit significantly elevated risk of suicide, yet the research literature contains very few outcome studies of interventions designed for suicidal inpatients. This pilot study examined the inpatient feasibility and effectiveness of The Collaborative Assessment and Management of Suicidality (CAMS), a structured evidence-based method for risk assessment and treatment planning (Jobes, 2006). The study used an open-trial, case-focused design to assess an inpatient adaptation of CAMS, spread over a period averaging 51 days. The intervention was provided via individual therapy to a convenience sample of 20 patients (16 females and four males, average age 36.9) who were hospitalized with recent histories of suicidal ideation and behavior. Results showed statistically and clinically significant reductions in depression, hopelessness, suicide cognitions, and suicidal ideation, as well as improvement on factors considered “drivers” of suicidality. Treatment effect sizes were in the large range (Cohen’s d > .80) across several outcome measures, including suicidal ideation. Although these findings must be considered preliminary due to the lack of a randomized control group, they merit attention from clinicians working with patients at risk for suicide. This study also supports the feasibility of implementing a structured, suicide-specific intervention for at-risk patients in inpatient settings.
suicide; CAMS; inpatient; psychotherapy; outcome
Few studies have examined the relation between suicide-related behaviors and Borderline Personality Disorder (BPD) in adolescent samples. The current study investigated the incremental validity of BPD relative to Major Depressive Disorder (MDD) for suicide-related behaviors in a psychiatric sample of adolescents at the cross-sectional level of analysis. The sample included N = 156 consecutive admissions (55.1% female; M age = 15.47; SD = 1.41), to the adolescent treatment program of an inpatient treatment facility. Of the sample 19.2% (n = 30) met criteria for BPD on the Child Interview for DSM-IV Borderline Personality Disorder and 39.1% (n = 61) met criteria for MDD on the Computerized Diagnostic Interview Schedule for Children–IV. Results showed that BPD conferred additional risk for suicidal ideation and deliberate self-harm. Our findings support the clinical impression that BPD should be evaluated in inpatient samples of adolescents either through intake interviews or more structured assessments.
Highly pathogenic avian influenza virus (HPAI) strain H5N1 has had direct and indirect economic impacts arising from direct mortality and control programmes in over 50 countries reporting poultry outbreaks. HPAI H5N1 is now reported as the most widespread and expensive zoonotic disease recorded and continues to pose a global health threat. The aim of this research was to assess the potential of utilising Hazard Analysis of Critical Control Points (HACCP) assessments in providing a framework for a rapid response to emerging infectious disease outbreaks. This novel approach applies a scientific process, widely used in food production systems, to assess risks related to a specific emerging health threat within a known zoonotic disease hotspot. We conducted a HACCP assessment for HPAI viruses within Vietnam’s domestic poultry trade and relate our findings to the existing literature. Our HACCP assessment identified poultry flock isolation, transportation, slaughter, preparation and consumption as critical control points for Vietnam’s domestic poultry trade. Introduction of the preventative measures highlighted through this HACCP evaluation would reduce the risks posed by HPAI viruses and pressure on the national economy. We conclude that this HACCP assessment provides compelling evidence for the future potential that HACCP analyses could play in initiating a rapid response to emerging infectious diseases.
Jellyfish form spectacular blooms throughout the world’s oceans. Jellyfish body plans are characterised by high water and low carbon contents which enables them to grow much larger than non-gelatinous animals of equivalent carbon content and to deviate from non-gelatinous pelagic animals when incorporated into allometric relationships. Jellyfish have, however, been argued to conform to allometric relationships when carbon content is used as the metric for comparison. Here we test the hypothesis that differences in allometric relationships for several key functional parameters remain for jellyfish even after their body sizes are scaled to their carbon content. Data on carbon and nitrogen contents, rates of respiration, excretion, growth, longevity and swimming velocity of jellyfish and other pelagic animals were assembled. Allometric relationships between each variable and the equivalent spherical diameters of jellyfish and other pelagic animals were compared before and after sizes of jellyfish were standardised for their carbon content. Before standardisation, the slopes of the allometric relationships for respiration, excretion and growth were the same for jellyfish and other pelagic taxa but the intercepts differed. After standardisation, slopes and intercepts for respiration were similar but excretion rates of jellyfish were 10× slower, and growth rates 2× faster than those of other pelagic animals. Longevity of jellyfish was independent of size. The slope of the allometric relationship of swimming velocity of jellyfish differed from that of other pelagic animals but because they are larger jellyfish operate at Reynolds numbers approximately 10× greater than those of other pelagic animals of comparable carbon content. We conclude that low carbon and high water contents alone do not explain the differences in the intercepts or slopes of the allometric relationships of jellyfish and other pelagic animals and that the evolutionary longevity of jellyfish and their propensity to form blooms is facilitated by their unique body plans.
Ebola virus (EBOV) infects several cell types and while viral entry is known to be pH dependent; the exact entry pathway(s) remains unknown. To gain insights into EBOV entry, the role of several inhibitors of clathrin-mediated endocytosis in blocking infection mediated by HIV pseudotyped with the EBOV envelope glycoprotein (EbGP) was examined. Wild type HIV and envelope-minus HIV pseudotyped with Vesicular Stomatitis Virus glycoprotein (VSVg) were used as controls to assess cell viability after inhibiting clathrin pathway. Inhibition of clathrin pathway using dominant-negative Eps15; siRNA-mediated knockdown of clathrin heavy chain; chlorpromazine and sucrose blocked EbGP pseudotyped HIV infection. Also, both chlorpromazine and Bafilomycin A1 inhibited entry of infectious EBOV. Sensitivity of EbGP pseudotyped HIV as well as infectious EBOV to inhibitors of clathrin suggests that EBOV uses clathrin-mediated endocytosis as an entry pathway. Furthermore, since chlorpromazine inhibits EBOV infection, novel therapeutic modalities could be designed based on this lead compound.
Ebola virus; Entry; Clathrin endocytic pathway; Chlorpromazine; Sucrose; Eps15
We previously mapped a locus (ahl4) on distal Chromosome 10 that contributes to the age-related hearing loss of A/J strain mice. Here, we report on a refined genetic map position for ahl4 and its association with a mutation in the citrate synthase gene (Cs). We mapped ahl4 to the distal-most 7 Mb of Chromosome 10 by analysis of a new linkage backcross and then further narrowed the interval to 5.5 Mb by analysis of eight C57BL/6J congenic lines with different A/J-derived segments of Chr 10. A nucleotide variant in exon 3 of Cs is the only known DNA difference within the ahl4 candidate gene interval that is unique to the A/J strain and that causes a nonsynonymous codon change. Multiple lines of evidence implicate this missense mutation (H55N) as the underlying cause of ahl4-related hearing loss, likely through its effects on mitochondrial ATP and free radical production in cochlear hair cells. The A/J mouse thus provides a new model system for in vivo studies of mitochondrial function and hearing loss.
mouse; genetics; inbred strain; A/J; age-related hearing loss; ahl4; citrate synthase; oxidative stress; mitochondria
Pathogen evolution and subsequent phenotypic heterogeneity during chronic infection are proposed to enhance Staphylococcus aureus survival during human infection. We tested this theory by genetically and phenotypically characterizing strains with mutations constructed in the mismatch repair (MMR) and oxidized guanine (GO) system, termed mutators, which exhibit increased spontaneous-mutation frequencies. Analysis of these mutators revealed not only strain-dependent increases in the spontaneous-mutation frequency but also shifts in mutational type and hot spots consistent with loss of GO or MMR functions. Although the GO and MMR systems are relied upon in some bacterial species to prevent reactive oxygen species-induced DNA damage, no deficit in hydrogen peroxide sensitivity was found when either of these DNA repair pathways was lost in S. aureus. To gain insight into the contribution of increased mutation supply to S. aureus pathoadaptation, we measured the rate of α-hemolysin and staphyloxanthin inactivation during serial passage. Detection of increased rates of α-hemolysin and staphyloxanthin inactivation in GO and MMR mutants suggests that these strains are capable of modifying virulence phenotypes implicated in mediating infection. Accelerated derivation of altered virulence phenotypes, combined with the absence of increased ROS sensitivity, highlights the potential of mutators to drive pathoadaptation in the host and serve as catalysts for persistent infections.
Approximately 10 percent of women with invasive epithelial ovarian cancer (EOC) carry deleterious germline mutations in BRCA1 or BRCA2. A recent report suggested that BRCA2 related EOC was associated with an improved prognosis, but the effect of BRCA1 remains unclear.
To characterize the survival of BRCA carriers with EOC compared to non-carriers and to determine whether BRCA1 and BRCA2 carriers show similar survival patterns.
Design, Setting, and Participants
We pooled data from 26 studies on the survival of women with ovarian cancer. This included data on 1,213 EOC cases with pathogenic germline mutations in BRCA1 (909) or BRCA2 (304) and 2,666 non-carriers recruited and followed for variable times between 1987 and 2010; the median year of diagnosis was 1998.
Main Outcome Measures
Five year overall mortality.
The five-year overall survival was 36 percent (95% CI: 34–38) for non-carriers, 44 percent (95% CI: 40–48) for BRCA1 carriers and 52 percent (95% CI: 46–58) for BRCA2 carriers. After adjusting for study and year of diagnosis, BRCA1 and BRCA2 carriers showed a more favorable survival than non-carriers (BRCA1, HR=0.78; 95% CI=0.68–0.89, P=2×10−4; BRCA2, HR = 0.61; 95% CI=0.50–0.76, P=6×10−6). These survival differences remained after additional adjustment for stage, grade, histology and age at diagnosis (BRCA1, HR=0.73, 95% CI=0.64–0.84, P=2×10−5; BRCA2, HR = 0.49, 95% CI=0.39–0.61, P=3×10−10).
Among patients with invasive epithelial ovarian cancer, having a germline mutation in BRCA1 or BRCA2 was associated with improved 5-year overall survival.
Recruitment of eosinophils has long been recognized as a hallmark of the inflammatory response in asthma. However, the functions of this population of cells in host defense remain poorly understood. Eosinophils play an important part in the inflammatory response and have key regulatory roles in the afferent arm of the immune response. More recently, eosinophils have been demonstrated to participate in host defense against respiratory viruses. The specific contributions of eosinophils to the pathophysiology of asthma remains controversial. However, the balance of evidence indicates that they have a significant role in the disease, suggesting that they may be appropriate targets for therapy. Towards this end, a novel intervention of considerable potential interest is the use of an antibody directed against the β-common chain of the receptor for interleukin-3, interleukin-5 and granulocyte-macrophage colony-stimulating factor. However, eliminating eosinophils may not be a risk-free therapeutic strategy, as there is potentially an increased likelihood of respiratory viral infections. This may predispose to the development of acute exacerbations of asthma, an outcome that would have significant clinical implications.
asthma; eosinophils; antiviral defense; interleukin-5 receptor; beta-common subunit
The phagocyte NADPH oxidase generates superoxide anion and downstream reactive oxidant intermediates in response to infectious threat, and is a critical mediator of antimicrobial host defense and inflammatory responses. Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature myeloid cells that are recruited by cancer cells, accumulate locally and systemically in advanced cancer, and can abrogate anti-tumor immunity. Prior studies have implicated the phagocyte NADPH oxidase as being an important component promoting MDSC accumulation and immunosuppression in cancer. We therefore used engineered NADPH oxidase-deficient (p47phox−/−) mice to delineate the role of this enzyme complex in MDSC accumulation and function in a syngeneic mouse model of epithelial ovarian cancer. We found that the presence of NADPH oxidase did not affect tumor progression. The accumulation of MDSCs locally and systemically was similar in tumor-bearing wild-type (WT) and p47phox−/− mice. Although MDSCs from tumor-bearing WT mice had functional NADPH oxidase, the suppressive effect of MDSCs on ex vivo stimulated T cell proliferation was NADPH oxidase-independent. In contrast to other tumor-bearing mouse models, our results show that MDSC accumulation and immunosuppression in syngeneic epithelial ovarian cancer is NADPH oxidase-independent. We speculate that factors inherent to the tumor, tumor microenvironment, or both determine the specific requirement for NADPH oxidase in MDSC accumulation and function.
Antimicrobial resistance among pneumococci has greatly increased over the past two to three decades. Resistance to tetracycline (tet(M)), chloramphenicol (cat) and macrolides (erm(B) and/or mef(A/E)) is generally conferred by acquisition of specific genes that are associated with mobile genetic elements, including those of the Tn916 and Tn5252 families. The first tetracycline-, chloramphenicol- and macrolide-resistant pneumococci were detected between 1962 and 1970; however, until now the oldest pneumococcus shown to harbour Tn916 and/or Tn5252 was isolated in 1974. In this study the genomes of 38 pneumococci isolated prior to 1974 were probed for the presence of tet(M), cat, erm(B), mef(A/E) and int (integrase) to indicate the presence of Tn916/Tn5252-like elements.
Two Tn916-like, tet(M)-containing, elements were identified among pneumococci dated 1967 and 1968. The former element was highly similar to that of the PMEN1 multidrug-resistant, globally-distributed pneumococcal reference strain, which was isolated in 1984. The latter element was associated with a streptococcal phage. A third, novel genetic element, designated ICESpPN1, was identified in the genome of an isolate dated 1972. ICESpPN1 contained a region of similarity to Tn5252, a region of similarity to a pneumococcal pathogenicity island and novel lantibiotic synthesis/export-associated genes.
These data confirm the existence of pneumococcal Tn916 elements in the first decade within which pneumococcal tetracycline resistance was described. Furthermore, the discovery of ICESpPN1 demonstrates the dynamic variability of pneumococcal genetic elements and is contrasted with the evidence for Tn916 stability.
Streptococcus pneumoniae; Antimicrobial resistance; Mobile genetic elements; Tetracycline resistance; ICE elements