Role of endoplasmic reticulum stress induction by the plant toxin, persin, in overcoming resistance to the apoptotic effects of tamoxifen in human breast cancer cells.

BACKGROUND: Persin is a plant toxin that displays synergistic cytotoxicity with tamoxifen in human breast cancer cell lines. Here, we examined the ability of persin to circumvent tamoxifen resistance and delineated the intracellular signalling pathways involved. METHODS: The induction of apoptosis in tamoxifen-resistant and -sensitive breast cancer cells was measured by flow cytometry following treatment with persin±tamoxifen. Markers of endoplasmic reticulum stress (ERS) were analysed following treatment, and their causal role in mediating persin-induced apoptosis was determined using chemical inhibitors and RNA interference. RESULTS: Cells that were resistant to an apoptotic concentration of tamoxifen maintained an apoptotic response to persin. Persin-induced apoptosis was associated with an increase in markers of ERS, that is, CHOP expression and XBP-1 splicing and was decreased by CHOP siRNA. The CASP-4 inhibitor Z-YVAD-FMK markedly inhibited persin-induced apoptosis in both tamoxifen-sensitive and -resistant cells. CONCLUSION: The cytotoxic effects of persin are CASP-4 dependent and mediated by CHOP-dependent and -independent ERS signalling cascades. Increased ERS signalling contributes to persin-induced reversal of tamoxifen resistance.

White Matter Cerebrovascular Reactivity: Effects of Microangiopathy and Proximal Occlusions on the Dynamic BOLD Response.

Introduction: Cerebral microangiopathy often manifests as white matter hyperintensities (WMH) on T2-weighted MR images and is associated with elevated stroke risk. Large vessel steno-occlusive disease (SOD) is also independently associated with stroke risk, however, the interaction of microangiopathy and SOD is not well understood. Cerebrovascular reactivity (CVR) describes the capacity of cerebral circulation to adapt to changes in perfusion pressure and neurovascular demand, and its impairment portends future infarctions. CVR can be measured with blood oxygen level dependent (BOLD) imaging following acetazolamide stimulus (ACZ-BOLD). We studied CVR differences between WMH and normal-appearing white matter (NAWM) in patients with chronic SOD, hypothesizing additive influences upon CVR measured by novel, fully dynamic CVR maxima ( CVR max ). Methods: A cross sectional study was conducted to measure per-voxel, per-TR maximal CVR ( CVR max ) using a custom computational pipeline in 23 subjects with angiographically-proven unilateral SOD. WMH and NAWM masks were applied to CVR max maps. White matter was subclassified with respect to the SOD-affected hemisphere, including: i. contralateral NAWM; ii. contralateral WMH iii. ipsilateral NAWM; iv. ipsilateral WMH. CVR max was compared between these groups with a Kruskal-Wallis test followed by a Dunn-Sidak post-hoc test for multiple comparisons. Results: 19 subjects (age 50±12 years, 53% female) undergoing 25 examinations met criteria. WMH volume was asymmetric in 16/19 subjects with 13/16 exhibiting higher volumes ipsilateral to SOD. Pairwise comparisons of CVR max between groups was significant with ipsilateral WMH CVR max lower than contralateral NAWM (p=0.015) and contralateral WMH (p=0.003) when comparing in-subject medians and lower than all groups when comparing pooled voxelwise values across all subjects (p<0.0001). No significant relationship between WMH lesion size and CVR max was detected. Conclusion: Our results suggest additive effects of microvascular and macrovascular disease upon white matter CVR, but with greater overall effects relating to macrovascular SOD than to apparent microangiopathy. Dynamic ACZ-BOLD presents a promising path towards a quantitative stroke risk imaging biomarker. BACKGROUND: Cerebral white matter (WM) microangiopathy manifests as sporadic or sometimes confluent high intensity lesions in MR imaging with T2-weighting, and bears known associations with stroke, cognitive disability, depression and other neurological disorders 1-5 . Deep white matter is particularly susceptible to ischemic injury owing to the deprivation of collateral flow between penetrating arterial territories, and hence deep white matter hyperintensities (WMH) may portend future infarctions 6-8 . The pathophysiology of WMH is variable but commonly includes a cascade of microvascular lipohyalinosis and atherosclerosis together with impaired vascular endothelial and neurogliovascular integrity, leading to blood brain barrier dysfunction, interstitial fluid accumulation, and eventually tissue damage 9-14 . Independent of the microcirculation, cervical and intracranial large vessel steno-occlusive disease (SOD) often results from atheromatous disease and is associated with increased risk of stroke owing to thromboembolic phenomena, hypoperfusion, or combinations thereof 15-17 . White matter disease is more common in the affected hemisphere of patients with asymmetric or unilateral SOD, producing both macroscopic WMH detectable by routine structural MRI, as well as microstructural changes and altered structural connectivity detected by advanced diffusion microstructural imaging 18, 19 . An improved understanding of the interaction of microvascular disease (i.e., WMH) and macrovascular steno-occlusion could better inform stroke risk stratification and guide treatment strategies when coexistent. Cerebrovascular reactivity (CVR) is an autoregulatory adaptation characterized by the capacity of the cerebral circulation to respond to physiological or pharmacological vasodilatory stimuli 20-22 . CVR may be heterogeneous and varies across tissue type and pathological states 1, 16 . Alterations in CVR are associated with elevated stroke risk in SOD patients, although white matter CVR, and in particular the CVR profiles of WMH, are only sparsely studied and not fully understood 1, 23-26 . We have previously employed blood oxygen level dependent (BOLD) imaging following a hemodynamic stimulus with acetazolamide (ACZ) in order to measure CVR (i.e. ACZ-BOLD) 21, 27, 28 . Despite the emergence of ACZ-BOLD as a technique for clinical and experimental use, poor signal-to-noise characteristics of the BOLD effect have generally limited its interpretation to coarse, time-averaged assessment of the terminal ACZ response at arbitrarily prescribed delays following ACZ administration (e.g. 10-20 minutes) 29 . More recently, we have introduced a dedicated computational pipeline to overcome historically intractable signal-to-noise ratio (SNR) limitations of BOLD, enabling fully dynamic characterization of the cerebrovascular response, including identification of previously unreported, unsustained or transient CVR maxima ( CVR max ) following hemodynamic provocation 27, 30 . In this study, we compared such dynamic interrogation of true CVR maxima between WMH and normal appearing white matter (NAWM) among patients with chronic, unilateral SOD in order to quantify their interaction and to assess the hypothesized additive effects of angiographically-evident macrovascular stenoses when intersecting microangiopathic WMH.

Autoimmune responses to the brain after stroke are associated with worse outcome.

BACKGROUND AND PURPOSE: Immune responses to brain antigens occur after stroke, and experimental studies show that the likelihood of developing a detrimental autoimmune response to these antigens is increased by systemic inflammation at the time of stroke. The aim of this study was to determine if patients who developed infection in the poststroke period would be similarly predisposed to develop autoimmune responses to central nervous system antigens. METHODS: We enrolled 114 patients within 72 hours of ischemic stroke. Clinical and demographic data were obtained, and cellular immune responses to a panel of central nervous system antigens were assessed during the initial week and again at Day 90. Outcome was assessed using the modified Rankin Scale. RESULTS: Patients who developed an infection, especially pneumonia, in the 15 days after stroke were more likely to evidence a Th1(+) response to myelin basic protein and glial fibrillary acidic protein (P=0.019 and P=0.039, respectively) at 90 days after stroke. Further, more robust Th1 responses to myelin basic protein at 90 days were associated with a decreased likelihood of good outcome, even after adjusting for baseline stroke severity and patient age (OR, 0.477; 95% CI, 0.244 to 0.935; P=0.031). CONCLUSIONS: This study demonstrates that immune responses to brain antigens occur after stroke. Although these responses are likely to be an epiphenomenon of ischemic brain injury, the response to myelin basic protein appears to have clinical consequences. The potential role of postischemic autoimmune-mediated brain injury deserves further investigation.

A novel g.-1258G>A mutation in a conserved putative regulatory element of PAX9 is associated with autosomal dominant molar hypodontia.

Mutations in the transcription factor PAX9 which plays a critical role in the switching of odontogenic potential from the epithelium to the mesenchyme during tooth development cause autosomal dominant non-syndromic hypodontia primarily affecting molars. Linkage analysis on a family segregating autosomal dominant molar hypodontia with markers flanking and within PAX9 yielded a maximum multipoint LOD score of 3.6. No sequence variants were detected in the coding or 5'- and 3'-untranslated regions (UTRs) of PAX9. However, we identified a novel g.-1258G>A sequence variant in all affected individuals of the family but not in the unaffected family members or in 3088 control chromosomes. This mutation is within a putative 5'-regulatory sequence upstream of PAX9 highly conserved in primates, somewhat conserved in ungulates and carnivores but not conserved in rodents. Bioinformatics analysis of the sequence determined that there was no abolition or creation of a putative binding site for known transcription factors. Based on our previous findings that haploinsufficiency for PAX9 leads to hypodontia, we postulate that the g.-1258G>A variant reduces the expression of PAX9 which underlies the hypodontia phenotype in this family.

Post-stroke infection: a role for IL-1ra?

BACKGROUND: Infection is common following stroke and is independently associated with worse outcome. Clinical studies suggest that infections occur more frequently in those individuals with stroke-induced immunologic dysfunction. This study sought to explore the contribution of immunomodulatory cytokines and hormones to lymphocyte function and infection risk. METHODS: Patients (N = 112) were enrolled as soon as possible after the onset of ischemic stroke. Blood was drawn to assess plasma cortisol, IL-10, IL-1ra, lymphocyte numbers, and lymphocyte function at 72 h after stroke onset; infections were censored through 21 days after stroke onset. RESULTS: Infection occurred in 25% of patients. Stroke severity was the most important predictor of infection risk. Increased plasma cortisol, IL-10, and IL-1ra, as well as decreased lymphocyte numbers, at 72 h after stroke onset were associated with risk of subsequent infection. After controlling for stroke severity, only IL-1ra was independently associated with infection risk, and the degree of risk was consistent throughout the post-stroke period. Infection, but not IL-1ra itself, was associated with worse outcome at 3 months. CONCLUSIONS: In this study cohort, increased plasma IL-1ra was independently associated with the risk of post-stroke infection. Further studies are needed to validate this finding, which could have important implications for stroke therapy.

Overexpression of TFAP2C in invasive breast cancer correlates with a poorer response to anti-hormone therapy and reduced patient survival.

The AP-2gamma transcription factor encoded by the TFAP2C gene is a member of a family of homologous DNA binding proteins that play essential roles during vertebrate embryogenesis but show a restricted pattern of expression in the adult. Elevated expression of the AP-2alpha and AP-2gamma family members has been associated with a number of neoplasms, particularly breast cancer. Here we present an exploratory immunohistochemical study of an archival primary breast tumour series (n = 75) with parallel clinicopathological data using a new, well-characterized antibody to AP-2gamma. Heterogeneous, exclusively nuclear expression of AP-2gamma was found in the epithelial and myoepithelial compartments of normal breast and within tumour epithelial cells. In the breast cancer series, the most notable association was a correlation between elevated levels of AP-2gamma and shortened patient survival (p = 0.0009*). This relationship was also conserved in ER-positive and ErbB2-negative patients; sub-groups generally considered to have a relatively good prognosis. When patient data for survival and duration of treatment response on anti-hormone therapy were examined by multivariate analysis, AP-2gamma was revealed in this study to be an independent predictor of outcome for both survival (p = 0.005) and response to anti-hormone therapy (p = 0.046). Studies using in vitro models confirmed that while tamoxifen response is associated with lower levels of AP-2gamma, acquisition of resistance to this and other anti-hormone measures (eg faslodex or oestrogen deprivation) is associated with high levels of nuclear AP-2gamma. Together these data suggest that elevated tumour AP-2gamma expression can contribute to the failure of cells to growth arrest following anti-hormone treatment and lead to sustained growth and poorer patient outcome.

CNS immune responses following experimental stroke.

BACKGROUND AND PURPOSE: Animals subjected to an inflammatory insult with lipopolysaccharide (LPS) at the time of stroke are predisposed to develop a detrimental autoimmune response to myelin basic protein (MBP). In this study, we sought to determine whether other inflammatory stimuli could similarly invoke central nervous system (CNS) autoimmunity and whether these detrimental autoimmune responses occurred to antigens other than MBP. METHODS: Male Lewis rats underwent 3 h middle cerebral artery occlusion (MCAO) and received intraperitoneal injections of LPS, staphylococcal enterotoxin B (SEB), lipoteichoic acid (LTA) or saline at the time of reperfusion. Behavioral tests were performed at set time intervals after MCAO and animals were sacrificed at 1 month to analyze the immune response to MBP, neuron specific enolase (NSE) and proteolipid protein (PLP). RESULTS: Lymphocytes from SEB treated animals were highly reactive to all tested CNS antigens, but treatment with LPS was most likely to lead to a TH: 1(+) response. A TH: 1(+) response to MBP, NSE or PLP in spleen was associated with worse outcome, although the response to NSE was most predictive of poor outcome. Animals with a cell mediated autoimmune response to either MBP or NSE in spleen had a concomitant humoral response to these antigens. CONCLUSIONS: These data show that LPS, but not other inflammatory stimuli, increase the likelihood of developing a detrimental autoimmune response to an array of brain antigens.

Human CD80/IL2 lentivirus transduced acute myeloid leukaemia cells enhance cytolytic activity in vitro in spite of an increase in regulatory CD4+ T cells in a subset of cultures.

Immunotherapeutic strategies are increasingly being explored as a method of enhancing anti-tumour immune responses in patients with acute myeloid leukaemia (AML). Regulatory CD4(+) T cells (Tregs) suppress effector T and natural killer (NK) cells and therefore pose a potential challenge to the efficacy of immunotherapy. AML cells transduced with a lentivirus expressing CD80 (B7.1) and IL2 (LV-CD80/IL2) are capable of stimulating T and NK cell cytotoxicity in vitro. This study examines the effect of CD80/IL2 modified AML cells on Treg number and function. We report a significant increase in the number of CD8(+) T cells (P = 0.046) CD3(-)CD56(+) NK cells (P = 0.028) and CD3(+)CD4(+)CD25(high)Foxp3(+) Tregs (P = 0.043) following stimulation for 7 days with allogeneic LV-CD80/IL2 AMLs. In contrast, autologous LV-CD80/IL2 AML cell cultures provide a weaker stimulation with a lower number of CD8(+) T cells (P = 0.011) and no change in NK cell or Treg numbers. However, an increase in cytotoxic CD8(+) T cells and NK cells are detected following both allogeneic and autologous LV-CD80/IL2 stimulation as demonstrated by an increase in IFN-gamma and CD107a expression. Despite the presence of increased numbers of Tregs with suppressive activity in a subset of cultures, increased lysis of unmodified AMLs was still achieved following allogeneic (day 0, 2.2%; day 7, 20.4%) and more importantly, autologous LV-CD80/IL2 culture in which AML patients had recently received intensive chemotherapy (day 0, 0%; day 7, 16%). Vaccination with LV-CD80/IL2 therefore provides a potential strategy to enhance anti-leukaemia immune responses without a concomitant stimulation of Treg-mediated inhibition of cytotoxic immunological responses.

Grain size--dependent alteration and the magnetization of oceanic basalts.

Unblocking temperatures of natural remanent magnetization were found to extend well above the dominant Curie points in samples of oceanic basalts from the axis of the East Pacific Rise. This phenomenon is attributed to the natural presence in the basalts of three related magnetic phases: an abundant fine-grained and preferentially oxidized titanomagnetite that carries most of the natural remanent magnetism, a few coarser and less oxidized grains of titanomagnetite that account for most of the high-field magnetic properties, and a small contribution to both the natural remanent magnetism and high-field magnetic properties from magnetite that may be due to the disproportionation of the oxidized titanomagnetite under sea-floor conditions. This model is consistent with evidence from the Central Anomaly magnetic high that the original magnetization acquired by oceanic basalts upon cooling is rapidly altered and accounts for the lack of sensitivity of bulk rock magnetic parameters to the degree of alteration of the remanence carrier in oceanic basalts.

Linoleic acid hydroperoxide: impaired bacterial uptake by alveolar macrophages, a mechanism of oxidant lung injury.

Exogenous linoleic acid hydroperoxide causes in vitro impairment of both bacterial uptake and the phagocytic stimulation of (14)CO(2) production from [1-(14)C]glucose in rabbit alveolar macrophages by an undefined effect on the cell membrane. This effect may be one mechanism for the defective pulmonary bacterial clearance characteristic of oxidant lung injury.

Asbestos: scientific developments and implications for public policy.

Asbestos is a commercial term for a group of fibrous minerals often associated with the development of pulmonary interstitial fibrosis (asbestosis), lung cancer, and malignant mesothelioma in occupationally exposed individuals. The pathogenicity of different forms of asbestos varies--long, thin amphibole fibers are most pathogenic, particularly in the induction of mesothelioma. Available data do not support the concept that low-level exposure to asbestos is a health hazard in buildings and schools. The concentration of asbestos fibers in air, type of asbestos, and size of fibers must be considered in evaluation of potential health risks.

Dissociation of bradycardia and arterial constriction during diving in the seal Phoca vitulina.

Bradycardia associated with diving in the harbor seal has been dissociated from the arterial constrictor response by intracardiac pacing. Development of arterial constriction does not depend upon the development of bradycardia. During pacing, arterial constriction continues in the absence of bradycardia. Increases in heart rate to values greater than 120 beats per minute during a dive produce a progressive decrease in mean aortic pressure, which suggests that one major function of bradycardia is to reduce cardiac output, thus matching left ventricular output to the restricted vascular bed and decreased venous return associated with diving.

Model-based evaluation of control strategies for phosphorus removal in a full-scale advanced phase isolation ditch process.

A model-based evaluation of operation conditions and control strategies was conducted for phosphorus removal in a full-scale Advanced Phase Isolation Ditch (APID) process. The APID process is an alternating type and does not have a separated anaerobic reactor. We suggested that it would be a suitable operational option for robust phosphorus removal by having a different input point for the influent and return sludge flow at specific modes. For evaluation of control strategies, three cases of influent disturbance were assumed, and five manipulated variables were selected for controlling the cases of disturbance. In the case of an increased influent flow rate, a combination of four manipulated variables is proposed through our simulation results as the best control strategy. The optimal k(L)a value was found to be 250/d when pollutants loading kept increasing without variations in the flow rate. When both the pollutants loading and the influent flow rates were increased simultaneously, the robust control strategy is to combine the return sludge inflow point, the exclusive operation modes which have a relatively long hydraulic retention time (HRT), operation period of 30 minutes, and the increase of the return sludge flow rate in proportion to the influent flow rate added to 300/d of k(L)a value.

Convolutional Neural Network for Automated FLAIR Lesion Segmentation on Clinical Brain MR Imaging.

BACKGROUND AND PURPOSE: Most brain lesions are characterized by hyperintense signal on FLAIR. We sought to develop an automated deep learning-based method for segmentation of abnormalities on FLAIR and volumetric quantification on clinical brain MRIs across many pathologic entities and scanning parameters. We evaluated the performance of the algorithm compared with manual segmentation and existing automated methods. MATERIALS AND METHODS: We adapted a U-Net convolutional neural network architecture for brain MRIs using 3D volumes. This network was retrospectively trained on 295 brain MRIs to perform automated FLAIR lesion segmentation. Performance was evaluated on 92 validation cases using Dice scores and voxelwise sensitivity and specificity, compared with radiologists' manual segmentations. The algorithm was also evaluated on measuring total lesion volume. RESULTS: Our model demonstrated accurate FLAIR lesion segmentation performance (median Dice score, 0.79) on the validation dataset across a large range of lesion characteristics. Across 19 neurologic diseases, performance was significantly higher than existing methods (Dice, 0.56 and 0.41) and approached human performance (Dice, 0.81). There was a strong correlation between the predictions of lesion volume of the algorithm compared with true lesion volume (ρ = 0.99). Lesion segmentations were accurate across a large range of image-acquisition parameters on >30 different MR imaging scanners. CONCLUSIONS: A 3D convolutional neural network adapted from a U-Net architecture can achieve high automated FLAIR segmentation performance on clinical brain MR imaging across a variety of underlying pathologies and image acquisition parameters. The method provides accurate volumetric lesion data that can be incorporated into assessments of disease burden or into radiologic reports.

Evaluation of Complications and Costs During Overlapping Transsphenoidal Surgery in the Treatment of Pituitary Adenoma.

BACKGROUND: Pituitary adenomas are among the most common primary brain tumors. Recently, overlapping surgery has been curbed in many institutions because of the suggestion there might be more significant adverse events, despite several studies showing that complication rates are equivalent. OBJECTIVE: To assess complications and costs associated with overlapping surgery during the transsphenoidal resection of pituitary adenomas. METHODS: A single-center, retrospective cohort study was performed to evaluate the cases of patients who underwent a transsphenoidal approach for pituitary tumor resection. Patient, surgical, complication, and cost (value-driven outcome) variables were analyzed. RESULTS: A total of 629 patients (302 nonoverlapping, 327 overlapping cases) were identified. No significant differences in age (P = .6), sex (P = .5), tumor type (P = .5), or prior rates of pituitary adenoma resection (P = .5) were seen. Similar presenting symptoms were observed in the 2 groups, and follow-up length was comparable (P = .3). No differences in tumor sizes (P = .5), operative time (P = .4), fat/fascia use (P = .4), or cerebrospinal fluid diversion (P = .8) were seen between groups. The gross total resection rate was not significantly different (P = .9), and no difference in recurrence rate was seen (P = .4). A comparable complication rate was seen between groups (P = .6). No differences in total or subtotal costs were seen either. CONCLUSION: The results of this study offer additional evidence that overlapping surgery does not result in worsened complications, lengthened surgery, or increased patient cost for patients undergoing transsphenoidal resection of pituitary adenomas. Thus, studies and policy aiming to improve patient safety and cost should focus on optimizing other aspects of healthcare delivery.

Induction of immunologic tolerance to myelin basic protein prevents central nervous system autoimmunity and improves outcome after stroke.

BACKGROUND AND PURPOSE: Animals subjected to an inflammatory insult at the time of stroke are predisposed to the development of an inflammatory autoimmune response to brain. This response is associated with worse neurological outcome. Because induction of immunologic tolerance to brain antigens before stroke onset is associated with improved outcome, we sought to determine whether this paradigm could prevent the deleterious autoimmune response to brain provoked by an inflammatory stimulus at the time of ischemia. METHODS: Male Lewis rats were tolerized to myelin basic protein (MBP) or ovalbumin by intranasal administration before middle cerebral artery occlusion. At the time of reperfusion, all animals received lipopolysaccharide (1 mg/kg intraperitoneal). Behavioral tests were performed at set time intervals. RESULTS: One month after middle cerebral artery occlusion, lymphocytes from the spleens of MBP-tolerized animals were less likely to evidence an autoimmune response and more likely to evidence a regulatory response (Treg) toward MBP than those from ovalbumin-tolerized animals. Animals that had an inflammatory response toward MBP (a Th1 response) performed worse on behavioral tests than those that did not. Fractalkine, a surrogate marker of inflammation, was elevated in animals with a Th1 response to MBP. CONCLUSIONS: These data extend our previous findings and suggest that deleterious autoimmunity to brain antigens can be prevented by prophylactically inducing regulatory T-cell responses to those antigens.

Development of a food frequency questionnaire for the assessment of quercetin and naringenin intake.

OBJECTIVES: To measure the relationship between quercetin and naringenin intakes as estimated by food frequency questionnaire (FFQ), and the urinary excretion of quercetin and naringenin aglycones after their enzymatic hydrolysis in human volunteers. SUBJECTS AND METHODS: Volunteers were recruited via the Human Nutrition Unit volunteer databank at the Institute of Food Research, Norwich. Sixty-three volunteers were recruited into the study, of which 14 were excluded and 49 completed the study. A modified FFQ was developed and used to estimate daily intake of quercetin and naringenin in 49 healthy volunteers who also provided five 24-h urine samples over a 2-week period. Urinary excretion of quercetin and naringenin metabolites was determined by solid-phase extraction and high-pressure liquid chromatography. RESULTS: The estimated mean intakes of quercetin and naringenin were 29.4 mg (s.d. 15.0) and 58.1 mg (s.d. 62.7) per day, respectively. Mean urinary excretion of quercetin was 60.1 microg (s.d. 33.1) and that of naringenin was 0.56 mg (s.d. 0.4). The correlation between FFQ estimated intake of quercetin and naringenin and levels excreted in the urine were r=0.82 (P<0.0001) and r=0.25 (P=0.05), respectively. CONCLUSIONS: We observed a statistically significant correlation between the urinary excretion of quercetin and naringenin metabolites and their dietary intake as estimated by FFQ. Use of FFQs in epidemiological studies requiring an estimate of flavonoid intake seems justified.

Acute postnatal exposure to brominated diphenylether 47 delays neuromotor ontogeny and alters motor activity in mice.

Polybrominated diphenyl ethers (PBDEs) are widely used commercial flame retardants that are accumulating in the environment. PBDEs may interfere with the development of key biological systems, thus leaving children vulnerable to functional impairments in adulthood. There is a growing literature of animal studies that show subtle changes in motor and cognitive function following acute or repeated perinatal exposure to PBDEs. 2,2',4,4'-Brominated diphenyl ether (BDE 47), a very stable PBDE congener, has been shown to accumulate in humans, perhaps as a breakdown product of other PBDEs. The current study examined developmental milestones in male C57BL/6 mice exposed to a single oral dose of BDE 47 (0, 1, 10, or 30 mg/kg) on postnatal day (PND) 10. Behavioral endpoints assessing sensory and motor maturation were examined on PNDs 12, 14, 16, 18, 32, and 88. Motor activity was also examined at 2 and 4 months in a separate group of mice. BDE 47 exposure (particularly the highest dose) significantly increased body weight on PND 47 and thereafter. There was altered ontogeny in a few measures of neuromotor development; however, other developmental milestones and sensory responses were not altered. Motor activity was altered at both 2 and 4 months, with BDE 47-treated mice (all dose groups) displaying pronounced hyperactivity at 4 months. These data indicate that acute exposure to BDE 47 during postnatal development may produce subtle changes in the development of neuromotor systems that may alter adult behavior.

Analysis of Whole-Genome Sequences for the Prediction of Penicillin Resistance and ß-Lactamase Activity in Bacillus anthracis.

Penicillin (PEN) is a low-cost option for anthrax treatment, but naturally occurring resistance has been reported. ß-Lactamase expression (bla1, bla2) in Bacillus anthracis is regulated by a sigma factor (SigP) and its cognate anti-sigma factor (RsiP). Mutations leading to truncation of RsiP were previously described as a basis for PEN resistance. Here, we analyze whole-genome sequencing (WGS) data and compare the chromosomal sigP-bla1 regions from 374 B. anthracis strains to determine the frequency of mutations, identify mutations associated with PEN resistance, and evaluate the usefulness of WGS for predicting PEN resistance. Few (3.5%) strains contained at least 1 of 11 different mutations in sigP, rsiP, or bla1. Nine of these mutations have not been previously associated with PEN resistance. Four strains showed PEN resistance (PEN-R) by conventional broth microdilution, including 1 strain with a novel frameshift in rsiP. One strain that carries the same rsiP frameshift mutation as that found previously in a PEN-R strain showed a PEN-susceptible (PEN-S) phenotype and exhibited decreased bla1 and bla2 transcription. An unexpectedly small colony size, a reduced growth rate, and undetectable ß-lactamase activity levels (culture supernatant and cell lysate) were observed in this PEN-S strain. Sequence analysis revealed mutations in genes associated with growth defects that may contribute to this phenotype. While B. anthracis rsiP mutations cannot be exclusively used to predict resistance, four of the five strains with rsiP mutations were PEN-R. Therefore, the B. anthracis sigP-bla1 region is a useful locus for WGS-based PEN resistance prediction, but phenotypic testing remains essential. IMPORTANCE Determination of antimicrobial susceptibility of B. anthracis is essential for the appropriate distribution of antimicrobial agents for postexposure prophylaxis (PEP) and treatment of anthrax. Analysis of WGS data allows for the rapid detection of mutations in antimicrobial resistance (AMR) genes in an isolate, but the presence of a mutation in an AMR gene does not always accurately predict resistance. As mutations in the anti-sigma factor RsiP have been previously associated with high-level penicillin resistance in a limited number of strains, we investigated WGS assemblies from 374 strains to determine the frequency of mutations and performed functional antimicrobial susceptibility testing. Of the five strains that contained mutations in rsiP, only four were PEN-R by functional antimicrobial susceptibility testing. We conclude that while sequence analysis of this region is useful for AMR prediction in B. anthracis, genetic analysis should not be used exclusively and phenotypic susceptibility testing remains essential.

Lymphocytes: potential mediators of postischemic injury and neuroprotection.

Antigen-nonspecific inflammation appears to contribute to postischemic brain injury. Because there is a breach in the integrity of the blood-brain barrier after stroke, the immune system encounters novel central nervous system (CNS) antigens that allow for the development of a CNS antigen-specific autoimmune response. The nature of the immune response generated on antigen encounter is determined by the microenvironment at the site of antigen encounter. For instance, a systemic inflammatory response, such as that which would accompany an infection, could alter the microenvironment in such a way as to promote the initiation of deleterious autoimmunity. If patients who develop an infection in the immediate poststroke period are predisposed toward a CNS autoimmune response, it might help to explain why infection after stroke is associated with increased disability. We present data to support this hypothesis and to show that the breach in the blood-brain barrier can also be capitalized on to modulate the immune response to create a neuroprotective environment after stroke.