Patterns of Growth and Decline in Lung Function in Persistent Childhood Asthma

BACKGROUND

Tracking longitudinal measurements of growth and decline in lung function in patients with persistent childhood asthma may reveal links between asthma and subsequent chronic airflow obstruction.

METHODS

We classified children with asthma according to four characteristic patterns of lung-function growth and decline on the basis of graphs showing forced expiratory volume in 1 second (FEV1), representing spirometric measurements performed from childhood into adulthood. Risk factors associated with abnormal patterns were also examined. To define normal values, we used FEV1 values from participants in the National Health and Nutrition Examination Survey who did not have asthma.

RESULTS

Of the 684 study participants, 170 (25%) had a normal pattern of lung-function growth without early decline, and 514 (75%) had abnormal patterns: 176 (26%) had reduced growth and an early decline, 160 (23%) had reduced growth only, and 178 (26%) had normal growth and an early decline. Lower baseline values for FEV1, smaller bronchodilator response, airway hyperresponsiveness at baseline, and male sex were associated with reduced growth (P<0.001 for all comparisons). At the last spirometric measurement (mean [±SD] age, 26.0±1.8 years), 73 participants (11%) met Global Initiative for Chronic Obstructive Lung Disease spirometric criteria for lung-function impairment that was consistent with chronic obstructive pulmonary disease (COPD); these participants were more likely to have a reduced pattern of growth than a normal pattern (18% vs. 3%, P<0.001).

CONCLUSIONS

Childhood impairment of lung function and male sex were the most significant predictors of abnormal longitudinal patterns of lung-function growth and decline. Children with persistent asthma and reduced growth of lung function are at increased risk for fixed airflow obstruction and possibly COPD in early adulthood. (Funded by the Parker B. Francis Foundation and others; ClinicalTrials.gov number, NCT00000575.).

Exosome-delivered circRNA promotes glycolysis to induce chemoresistance through the miR-122-PKM2 axis in colorectal cancer

Malignant tumors, including colorectal cancer (CRC), usually rely on ATP generation through aerobic glycolysis for both rapid growth and chemotherapy resistance. The M2 isoform of pyruvate kinase (PKM2) has a key role in catalyzing glycolysis, and PKM2 expression varies even within a single tumor. In this study, we confirmed that expression of PKM2 is heterogeneous in CRC cells, namely high in oxaliplatin-resistant cells but relatively low in sensitive cells, and found that chemoresistant cells had enhanced glycolysis and ATP production. In addition, we report a PKM2-dependent mechanism through which chemosensitive cells may gradually transform into chemoresistant cells. The circular RNA hsa_circ_0005963 (termed ciRS-122 in this study), which was determined to be a sponge for the PKM2-targeting miR-122, was positively correlated with chemoresistance. In vitro and in vivo studies showed that exosomes from oxaliplatin-resistant cells delivered ciRS-122 to sensitive cells, thereby promoting glycolysis and drug resistance through miR-122 sponging and PKM2 upregulation. Moreover, si-ciRS-122 transported by exosomes could suppress glycolysis and reverse resistance to oxaliplatin by regulating the ciRS-122-miR-122-PKM2 pathway in vivo. Exosomes derived from chemoresistant CRC cells could transfer ciRS-122 across cells and promote glycolysis to reduce drug susceptibility in chemosensitive cells. This intercellular signal delivery suggests a potential novel therapeutic target and establishes a foundation for future clinical applications in drug-resistant CRC.

The development, maturation, and turnover rate of mouse spleen dendritic cell populations

Three distinct subtypes of dendritic cells (DC) are present in mouse spleen, separable as CD4(-)8alpha(-), CD4(+)8alpha(-), and CD4(-)8alpha(+) DC. We have tested whether these represent stages of development or activation within one DC lineage, or whether they represent separate DC lineages. All three DC subtypes appear relatively mature by many criteria, but all retain a capacity to phagocytose particulate material in vivo. Although further maturation or activation could be induced by bacterially derived stimuli, phagocytic capacity was retained, and no DC subtype was converted to the other. Continuous elimination of CD4(+)8(-) DC by Ab depletion had no effect on the levels of the other DC subtypes. Bromodeoxyuridine labeling experiments indicated that all three DC subtypes have a rapid turnover (half-life, 1.5-2.9 days) in the spleen, with none being the precursor of another. The three DC subtypes showed different kinetics of development from bone marrow precursors. The CD8alpha(+) spleen DC, apparently the most mature, displayed an extremely rapid turnover based on bromodeoxyuridine uptake and the fastest generation from bone marrow precursors. In conclusion, the three splenic DC subtypes behave as rapidly turning over products of three independent developmental streams.

Exosomal circRNA derived from gastric tumor promotes white adipose browning by targeting the miR-133/PRDM16 pathway

Cancer-related cachexia is a metabolic syndrome characterized by a wasting disorder of adipose and skeletal muscle and is accompanied by body weight loss and systemic inflammation. The treatment options for cancer cachexia are limited, and the molecular mechanism remains poorly understood. Circular RNAs (circRNAs) are a novel family of endogenous noncoding RNAs that have been proposed to regulate gene expression in mammals. Exosomes are small vesicles derived from cells, and recent studies have shown that circRNAs are stable in exosomes. However, little is known about the biological role of circRNAs in exosomes. In our study, we showed that circRNAs in plasma exosomes have specific expression features in gastric cancer (GC), and ciRS-133 is linked with the browning of white adipose tissue (WAT) in GC patients. Exosomes derived from GC cells deliver ciRS-133 into preadipocytes, promoting the differentiation of preadipocytes into brown-like cells by activating PRDM16 and suppressing miR-133. Moreover, knockdown of ciRS-133 reduced cancer cachexia in tumor-implanted mice, decreasing oxygen consumption and heat production. Thus, exosome-delivered circRNAs are involved in WAT browning and play a key role in cancer-associated cachexia.

Endometrial microbiome at the time of embryo transfer: next-generation sequencing of the 16S ribosomal subunit

PURPOSE

Characterization of the human microbiome has become more precise with the application of powerful molecular tools utilizing the unique 16S ribosomal subunit's hypervariable regions to greatly increase sensitivity. The microbiome of the lower genital tract can prognosticate obstetrical outcome while the upper reproductive tract remains poorly characterized. Here, the endometrial microbiome at the time of single embryo transfer (SET) is characterized by reproductive outcome.

METHODS

Consecutive patients undergoing euploid, SET was included in the analysis. After embryo transfer, performed as per routine, the most distal 5-mm portion of the transfer catheter was sterilely placed in a DNA free PCR tube. Next-generation sequencing of the bacteria specific 16S ribosome gene was performed, allowing genus and species calls for microorganisms.

RESULTS

Taxonomy assignments were made on 35 samples from 33 patients and 2 Escherichia coli controls. Of the 33 patients, 18 had ongoing pregnancies and 15 did not. There were a total of 278 different genus calls present across patient samples. The microbiome at time of transfer for those patients with ongoing pregnancy vs. those without ongoing pregnancy was characterized by top genera by sum fraction. Lactobacillus was the top species call for both outcomes.

CONCLUSIONS

The data presented here show the microbiome at the time of embryo transfer can successfully be characterized without altering standard clinical practice. This novel approach, both in specimen collection and analysis, is the first step toward the goal of determining physiologic from pathophysiologic microbiota. Further studies will help delineate if differences in the microbiome at the time of embryo transfer have a reliable impact on pregnancy outcome.

Androgen receptor splice variants activating the full-length receptor in mediating resistance to androgen-directed therapy

Upregulation of constitutively-active androgen receptor splice variants (AR-Vs) has been implicated in AR-driven tumor progression in castration-resistant prostate cancer. To date, functional studies of AR-Vs have been focused mainly on their ability to regulate gene expression independent of the full-length AR (AR-FL). Here, we showed that AR-V7 and ARv567es, two major AR-Vs, both facilitated AR-FL nuclear localization in the absence of androgen and mitigated the ability of the antiandrogen enzalutamide to inhibit AR-FL nuclear trafficking. AR-V bound to the promoter of its specific target without AR-FL, but co-occupied the promoter of canonical AR target with AR-FL in a mutually-dependent manner. AR-V expression attenuated both androgen and enzalutamide modulation of AR-FL activity/cell growth, and mitigated the in vivo antitumor efficacy of enzalutamide. Furthermore, ARv567es levels were upregulated in xenograft tumors that had acquired enzalutamide resistance. Collectively, this study highlights a dual function of AR-Vs in mediating castration resistance. In addition to trans-activating target genes independent of AR-FL, AR-Vs can serve as a "rheostat" to control the degree of response of AR-FL to androgen-directed therapy via activating AR-FL in an androgen-independent manner. The findings shed new insights into the mechanisms of AR-V-mediated castration resistance and have significant therapeutic implications.

Androgen Receptor Splice Variants Dimerize to Transactivate Target Genes

Constitutively active androgen receptor splice variants (AR-V) lacking the ligand-binding domain have been implicated in the pathogenesis of castration-resistant prostate cancer and in mediating resistance to newer drugs that target the androgen axis. AR-V regulates expression of both canonical AR targets and a unique set of cancer-specific targets that are enriched for cell-cycle functions. However, little is known about how AR-V controls gene expression. Here, we report that two major AR-Vs, termed AR-V7 and AR(v567es), not only homodimerize and heterodimerize with each other but also heterodimerize with full-length androgen receptor (AR-FL) in an androgen-independent manner. We found that heterodimerization of AR-V and AR-FL was mediated by N- and C-terminal interactions and by the DNA-binding domain of each molecule, whereas AR-V homodimerization was mediated only by DNA-binding domain interactions. Notably, AR-V dimerization was required to transactivate target genes and to confer castration-resistant cell growth. Our results clarify the mechanism by which AR-Vs mediate gene regulation and provide a pivotal pathway for rational drug design to disrupt AR-V signaling as a rational strategy for the effective treatment of advanced prostate cancer.

Endogenous gamma interferon mediates resistance to Brucella abortus infection

Depletion of endogenous gamma interferon (IFN-gamma) with anti-IFN-gamma monoclonal antibody resulted in increased numbers of Brucella abortus in the spleen and liver of infected CBA mice. This increase was accompanied by a decrease in splenomegaly and a lower proportion of macrophages in the spleen. Furthermore, treatment of recipient mice with anti-IFN-gamma antibody blocked the adoptive transfer of resistance with immune T cells. Together, the results indicated that endogenous IFN-gamma plays an important role in mediating resistance to primary and secondary Brucella infection.

Mapping pathological phenotypes in a mouse model of CDKL5 disorder

Mutations in cyclin-dependent kinase-like 5 (CDKL5) cause early-onset epileptic encephalopathy, a neurodevelopmental disorder with similarities to Rett Syndrome. Here we describe the physiological, molecular, and behavioral phenotyping of a Cdkl5 conditional knockout mouse model of CDKL5 disorder. Behavioral analysis of constitutive Cdkl5 knockout mice revealed key features of the human disorder, including limb clasping, hypoactivity, and abnormal eye tracking. Anatomical, physiological, and molecular analysis of the knockout uncovered potential pathological substrates of the disorder, including reduced dendritic arborization of cortical neurons, abnormal electroencephalograph (EEG) responses to convulsant treatment, decreased visual evoked responses (VEPs), and alterations in the Akt/rpS6 signaling pathway. Selective knockout of Cdkl5 in excitatory and inhibitory forebrain neurons allowed us to map the behavioral features of the disorder to separable cell-types. These findings identify physiological and molecular deficits in specific forebrain neuron populations as possible pathological substrates in CDKL5 disorder.

Effects of combination of ACE inhibitor and angiotensin receptor blocker on cardiac remodeling, cardiac function, and survival in rat heart failure

BACKGROUND

The mechanism and treatment of diastolic heart failure are poorly understood. We compared the effects of an ACE inhibitor, an angiotensin receptor blocker (ARB), and their combination on diastolic heart failure in Dahl salt-sensitive (DS) rats.

METHODS AND RESULTS

DS rats fed an 8% NaCl diet from 7 weeks of age were treated with benazepril 10 mg/kg alone, valsartan 30 mg/kg alone, or combined benazepril and valsartan at 5 and 15 mg/kg, respectively, or at 1 and 3 mg/kg, respectively. At 16 weeks of age, DS rats exhibited prominent concentric left ventricular (LV) hypertrophy and diastolic dysfunction with preserved systolic function, as estimated by echocardiography. Despite comparable hypotensive effects among all drug treatments, the combination of benazepril 5 mg/kg and valsartan 15 mg/kg improved diastolic dysfunction and survival in DS rats more effectively than ACE inhibitor or ARB alone. Furthermore, the increase in LV endothelin-1 levels and hydroxyproline contents in DS rats was significantly suppressed only by combined benazepril and valsartan, and LV atrial natriuretic peptide mRNA upregulation in DS rats was suppressed to a greater extent by the combination therapy than monotherapy.

CONCLUSIONS

The combination of ACE inhibitor and ARB, independently of the hypotensive effect, improved LV phenotypic change and increased LV endothelin-1 production and collagen accumulation, diastolic dysfunction, and survival in a rat heart failure model more effectively than either agent alone, thereby providing solid experimental evidence that the combination of these 2 agents is more beneficial than monotherapy for treatment of heart failure.

Tumor necrosis factor alpha and interleukin-12 contribute to resistance to the intracellular bacterium Brucella abortus by different mechanisms

Both interleukin-12 (IL-12) and tumor necrosis factor alpha (TNF-alpha) are produced early in intracellular bacterial infection. Depletion of either IL-12 or TNF-alpha by a single injection of specific antibody 4 h before the injection of Brucella abortus 19 led to the exacerbation of infection 2 weeks later. Whereas the effect of IL-12 depletion on resistance was persistent and exacerbation was still significant 6 weeks later, the bacterial numbers in mice depleted of TNF-alpha were similar to the bacterial numbers in control infected mice by 6 weeks postinfection. Massive splenomegaly, which is often seen in 2-week Brucella-infected mice, was not observed in IL-12- or TNF-alpha-depleted mice. Both IL-12- and TNF-alpha-depleted mice showed reduced cell accumulation in the spleen compared with the massive cell accumulation in control infected mice. Granuloma formation in livers was much reduced in IL-12-depleted mice but not in TNF-alpha-depleted mice. Gamma interferon (IFN-gamma) production by cells from TNF-alpha-depleted mice was not significantly different from that of cells from control infected mice. In contrast, the production of IFN-gamma by both CD4+ and CD8+ T cells from IL-12-depleted mice was greatly reduced, compared with that from control infected mice. This effect was still observed when the antibody injection was delayed for up to 7 days postinfection, but injections of anti-IL-12 antibody into mice with established Brucella infection had no significant effect on IFN-gamma production by T cells. Taken together, these results suggested that IL-12 contributed to resistance mainly via an IFN-gamma-dependent pathway and had a profound effect on the induction of acquired cellular resistance. In contrast, TNF-alpha was involved in resistance possibly via direct action on effector cells and may not be essential for the induction of acquired cellular resistance.

Gene transfer of dominant-negative mutants of extracellular signal-regulated kinase and c-Jun NH2-terminal kinase prevents neointimal formation in balloon-injured rat artery

We previously reported that extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK), belonging to mitogen-activated protein kinases, are rapidly activated in balloon-injured artery. Therefore, we examined the role of these kinase activations in neointimal formation by using an in vivo gene transfer technique. We made the dominant-negative mutants of ERK (DN-ERK) and JNK (DN-JNK) to specifically inhibit endogenous ERK and JNK activation, respectively. Before balloon injury, these mutants were transfected into rat carotid artery using the hemagglutinating virus of Japan liposome method. In vivo transfection of DN-ERK and DN-JNK significantly suppressed the activation of ERK and JNK, respectively, after balloon injury, confirming successful expression of the transfected genes. Neointimal formation at 14 and 28 days after injury was prevented by gene transfer of DN-ERK or DN-JNK. Furthermore, bromodeoxyuridine labeling index and total cell-counting analysis at 7 days showed that either DN-ERK or DN-JNK remarkably suppressed smooth muscle cell (SMC) proliferation in both the intima and the media after injury. Gene transfer of wild-type ERK (W-ERK) or JNK (W-JNK) significantly enhanced neointimal hyperplasia at 14 days after injury. Furthermore, DN-ERK and DN-JNK significantly suppressed serum-induced SMC proliferation in vitro. We obtained the first evidence that in vivo gene transfer of DN-ERK or DN-JNK prevented neointimal formation in balloon-injured artery by inhibiting SMC proliferation. Thus, ERK and JNK activation triggers SMC proliferation, leading to neointimal formation. These kinases may be the new therapeutic targets for prevention of vascular diseases.

Tractography dissection variability: What happens when 42 groups dissect 14 white matter bundles on the same dataset?

White matter bundle segmentation using diffusion MRI fiber tractography has become the method of choice to identify white matter fiber pathways in vivo in human brains. However, like other analyses of complex data, there is considerable variability in segmentation protocols and techniques. This can result in different reconstructions of the same intended white matter pathways, which directly affects tractography results, quantification, and interpretation. In this study, we aim to evaluate and quantify the variability that arises from different protocols for bundle segmentation. Through an open call to users of fiber tractography, including anatomists, clinicians, and algorithm developers, 42 independent teams were given processed sets of human whole-brain streamlines and asked to segment 14 white matter fascicles on six subjects. In total, we received 57 different bundle segmentation protocols, which enabled detailed volume-based and streamline-based analyses of agreement and disagreement among protocols for each fiber pathway. Results show that even when given the exact same sets of underlying streamlines, the variability across protocols for bundle segmentation is greater than all other sources of variability in the virtual dissection process, including variability within protocols and variability across subjects. In order to foster the use of tractography bundle dissection in routine clinical settings, and as a fundamental analytical tool, future endeavors must aim to resolve and reduce this heterogeneity. Although external validation is needed to verify the anatomical accuracy of bundle dissections, reducing heterogeneity is a step towards reproducible research and may be achieved through the use of standard nomenclature and definitions of white matter bundles and well-chosen constraints and decisions in the dissection process.

Endogenous interleukin-12 is involved in resistance to Brucella abortus infection

Protective immunity against Brucella abortus is mediated by acquired cellular resistance, with gamma interferon (IFN-gamma)-producing T cells playing a key role. Interleukin-12 (IL-12) is a cytokine that has a profound effect on the induction of IFN-gamma-producing Th1 and NK cells. Here we report that depletion of endogenous IL-12 before infection of mice significantly exacerbated brucella infection. IL-12-depleted mice also had reduced splenomegaly resulting from infection and showed a decrease in percentage and absolute numbers of macrophages compared with those in control infected mice. Furthermore, spleen cells from IL-12-depleted mice had a reduced ability to produce nitrite, a product of activated macrophages. This could be the result of the low production of IFN-gamma by splenic T cells observed in the IL-12-depleted mice. The mechanism whereby IL-12 controls antibacterial resistance is discussed.

Design, synthesis, and initial evaluation of high-affinity technetium bombesin analogues

Potent antagonists of bombesin-like peptides have shown great potential for applications in cancer therapy. A 99mTc-labeled agent capable of identifying patients who could benefit from these emerging therapies would have a great impact on patient management. This study involves the synthesis and initial evaluation of technetium diaminedithiolate analogues derived from the potent bombesin analogue Pyr-Gln-Lys-Leu-Gly-Asn-Gln-Trp-Ala-Val-Gly-His-Leu-Met-NH2 (Lys3-bombesin). We coupled two diaminedithiol (DADT) bifunctional chelating agents (BCAs 1 and 2) to the Lys3 residue at the N-terminal region that is not required for binding to the receptor. 99mTc labeling was performed by ligand exchange on addition of [99mTc]glucoheptonate to a solution of the adduct at room temperature. Two products were obtained from each adduct on analysis by HPLC. The major to minor product ratios of the 99mTc-labeled analogues were 3:1 for products from BCA 1 and 9:1 for the products from BCA 2. Macroscopic amounts of the 99Tc analogues were similarly prepared using [99Tc]glucoheptonate. In this case, the major to minor ratios were 2:1 for the products from both BCAs. For initial evaluation of the binding of the Tc-labeled peptides to bombesin receptors, the 99Tc analogues were used in vitro in competitive binding assays in rat brain cortex membranes against [125I-Tyr4]bombesin. Results of the in vitro assays showed that the inhibition constants (Ki) of the major and minor products were 3.5+/-0.7 and 3.9+/-1.5 nM, respectively, for the products from BCA 1; and 7.4+/-2.0 and 5.2+/-1.5 nM for the products derived from BCA 2, respectively. The high affinity exhibited by these technetium analogues is an indication of their potential for use in non-invasive in vivo biochemical characterization of cancers that possess receptors for bombesin.

Activation of the Akt-related cytokine-independent survival kinase requires interaction of its phox domain with endosomal phosphatidylinositol 3-phosphate

Protein kinases of the Akt and related serum- and glucocorticoid-regulated kinase (SGK) families are major downstream mediators of phosphatidylinositol (PI) 3-kinase signaling to many cellular processes including metabolic flux, membrane trafficking, and apoptosis. Activation of these kinases is thought to occur at the plasma membrane through their serine and threonine phosphorylation by the phosphoinositide-dependent kinase 1 (PDK1) protein kinase, which interacts with membrane 3'-polyphosphoinositides through its pleckstrin homology (PH) domain. Here, we demonstrate that the SGK family member cytokine-independent survival kinase (CISK) binds strongly and selectively to the monophosphoinositide PI(3)P through its phox homology (PX) domain. Comparing native green fluorescent protein-CISK (EGFP-CISK) to a mutant EGFP-CISK (Y51A) that displays attenuated binding to PI(3)P reveals that this interaction is both necessary and sufficient for its localization to early endosome antigen (EEA1)-positive endosomes. Furthermore, early endosome association of expressed epitope-tagged CISK in COS cells directed by binding of its PX domain to PI(3)P is required for activation of the CISK protein kinase by both insulin-like growth factor-1 and epidermal growth factor. Taken together, these results reveal a critical role of endosomal PI(3)P in the signal transmission mechanism whereby this survival kinase is activated in response to PI3-kinase stimulation by growth factors.

Association of left atrial volume index and all-cause mortality in patients referred for routine cardiovascular magnetic resonance: a multicenter study

BACKGROUND

Routine cine cardiovascular magnetic resonance (CMR) allows for the measurement of left atrial (LA) volumes. Normal reference values for LA volumes have been published based on a group of European individuals without known cardiovascular disease (CVD) but not on one of similar United States (US) based volunteers. Furthermore, the association between grades of LA dilatation by CMR and outcomes has not been established. We aimed to assess the relationship between grades of LA dilatation measured on CMR based on US volunteers without known CVD and all-cause mortality in a large, multicenter cohort of patients referred for a clinically indicated CMR scan.

METHOD

We identified 85 healthy US subjects to determine normal reference LA volumes using the biplane area-length method and indexed for body surface area (LAVi). Clinical CMR reports of patients with LA volume measures (n = 11,613) were obtained. Data analysis was performed on a cloud-based system for consecutive CMR exams performed at three geographically distinct US medical centers from August 2008 through August 2017. We identified 10,890 eligible cases. We categorized patients into 4 groups based on LAVi partitions derived from US normal reference values: Normal (21-52 ml/m2), Mild (52-62 ml/m2), Moderate (63-73 ml/m2) and Severe (> 73 ml/m2). Mortality data were ascertained for the patient group using electronic health records and social security death index. Cox proportional hazard risk models were used to derive hazard ratios for measuring association of LA enlargement and all-cause mortality.

RESULTS

The distribution of LAVi from healthy subjects without known CVD was 36.3 ± 7.8 mL/m2. In clinical patients, enlarged LA was associated with older age, atrial fibrillation, hypertension, heart failure, inpatient status and biventricular dilatation. The median follow-up duration was 48.9 (IQR 32.1-71.2) months. On univariate analyses, mild [Hazard Ratio (HR) 1.35 (95% Confidence Interval [CI] 1.11 to 1.65], moderate [HR 1.51 (95% CI 1.22 to 1.88)] and severe LA enlargement [HR 2.14 (95% CI 1.81 to 2.53)] were significant predictors of death. After adjustment for significant covariates, moderate [HR 1.45 (95% CI 1.1 to 1.89)] and severe LA enlargement [HR 1.64 (95% CI 1.29 to 2.08)] remained independent predictors of death.

CONCLUSION

LAVi determined on routine cine-CMR is independently associated with all-cause mortality in patients undergoing a clinically indicated CMR.

Gender Differences in Regional Brain Activity in Patients with Chronic Primary Insomnia: Evidence from a Resting-State fMRI Study

STUDY OBJECTIVES

To explore the regional brain activities in patients with chronic primary insomnia (PCPIs) and their sex differences.

METHODS

Forty-two PCPIs (27 females, 15 males) and 42 good sleepers (GSs; 24 females, 18 males) were recruited. Six PCPIs (3 males, 3 females) were scanned twice by MRI to examine the test-retest reliability. Amplitude of low frequency fluctuation (ALFF) method was used to assess the local brain features. The mean signal values of the different ALFF areas were analyzed with a receiver operating characteristic (ROC) curve. Simple linear regression analysis was performed to investigate the relationships between clinical features and different brain areas.

RESULTS

Both female and male PCPIs showed higher ALFF in the temporal lobe and occipital lobe, especially in female PCPIs. Female PCPIs had lower ALFF in the bilateral cerebellum posterior lobe, left dorsolateral prefrontal cortex, and bilateral limbic lobe; however, male PCPIs showed lower ALFF in the left occipital gyrus. The mean signal value of the cerebellum in female PCPIs showed negative correlations with negative emotions. Compared with male PCPIs, female PCPIs showed higher ALFF in the bilateral middle temporal gyrus and lower ALFF in the left limbic lobe. The different areas showed high test-retest stability (Clusters of contiguous volumes ≥ 1080 mm(3) with an intraclass correlation coefficient ≥ 0.80) and high degree of sensitivity and specificity.

CONCLUSIONS

Female PCPIs showed more regional brain differences with higher and lower ALFF responses than male PCPIs. However, they shared analogous excessive hyperarousal mechanism and wide variations in aberrant brain areas.

Use of suppression subtractive hybridization for differential gene expression in stroke: discovery of CD44 gene expression and localization in permanent focal stroke in rats

BACKGROUND AND PURPOSE

CD44 is a transmembrane glycoprotein involved in endothelial cell recognition, lymphocyte trafficking, and regulation of cytokine gene expression in inflammatory diseases. The present report describes the discovery of upregulated CD44 gene expression and its spatial and temporal distribution in the brain after focal stroke.

METHODS

Rats were subjected to permanent occlusion of the middle cerebral artery (MCAO). Suppression subtractive hybridization (SSH) strategy was used to identify differentially expressed genes. Northern blotting and real-time polymerase chain reaction were used to evaluate the expression of CD44 and hyaluronan synthase 2 (HAS-2) mRNA. Western blotting and immunohistochemistry were used to examine CD44 expression and cellular distribution.

RESULTS

CD44 upregulation after focal stroke was discovered by the SSH approach and confirmed by DNA sequencing. Northern blot using a pooled poly(A)+ RNA revealed 3 splice variants of CD44 mRNA, and their inducible expression started at 6 hours (5.3-fold increase over sham operation), peaked at 24 hours (28.6-fold increase), and persisted up to 72 hours (17.8-fold increase) after MCAO. A parallel induction profile of HAS-2 mRNA was observed in the ischemic brain tissue. The levels of CD44 were markedly elevated at 6 hours (1.8-fold increase over sham; n=3), 24 hours (2.9-fold, peak induction; P<0.01), and 72 hours (2.4-fold increase; P<0.05) after MCAO by means of Western analysis. Immunohistochemical and confocal microscopy confirmed that constitutive expression of CD44 is limited to microvessels in normal brain but is strongly induced after ischemia, where the immunoreactive signal mainly resided in endothelial cells and monocytes. Double-labeling immunohistochemistry demonstrated that a marked induction of CD44 in the ischemic lesion is dominantly located in microglia and a subset of macrophages.

CONCLUSIONS

The discovery of concomitant induction of CD44 and HAS-2 mRNA expression and the localization of CD44 in the microglia, macrophages, and microvessels of the ischemic brain tissue suggest that an active interaction between CD44 and hyaluronan may occur and play a role in the known inflammatory response and tissue remodeling after stroke.

Detecting time-dependent coherence between non-stationary electrophysiological signals--a combined statistical and time-frequency approach

Various time-frequency methods have been used to study time-varying properties of non-stationary neurophysiological signals. In the present study, a time-frequency coherence estimate using continuous wavelet transform (CWT) together with its confidence intervals are proposed to evaluate the correlation between two non-stationary processes. The approach is based on averaging over repeat trials. A systematic comparison between approaches using CWT and short-time Fourier transform (STFT) is carried out. Simulated data are generated to test the performance of these methods when estimating time-frequency based coherence. In contrast to some recent studies, we find that CWT based coherence estimates do not supersede STFT based estimates. We suggest that a combination of STFT and CWT would be most suitable for analysing non-stationary neural data. Tests are presented to investigate the time and frequency discrimination capabilities of the two approaches. The methods are applied to two experimental data sets: electroencephalogram (EEG) and surface electromyogram (EMG) during wrist movements in a healthy subject, and local field potential (LFP) and surface EMG recordings during resting tremor in a Parkinsonian patient. Supporting software is available at and .

Effects of Müller cell disruption on mouse photoreceptor cell development

Müller cells have been proposed to play an important role in photoreceptor cell development during the final stages of retinal maturation. The effect of disrupting Müller cells during mouse retinal development was investigated using the specific glial cell toxin, DL-alpha-aminoadipic acid (AAA). By giving multiple systemic injections over several days, impairment of Müller cell function was maintained during the period of photoreceptor migration and differentiation. Following three consecutive days of AAA treatment [commencing on post-natal (P) day 3, 5, 7 or 9, and examined at P8-P14], clumps of photoreceptor nuclei were displaced through the inner segments, lying immediately beneath the retinal pigment epithelium (RPE). Apart from the scalloped appearance of the outer retina, the overall lamination pattern of the retina was relatively well preserved. Even when AAA treatment commenced as early as P3, several days prior to the formation of the outer nuclear layer, the majority of photoreceptors migrated to their correct position and formed inner and outer segments. Therefore, the signals for photoreceptor migration are either provided by the Müller cells prior to P3, or, alternatively, are derived from different intrinsic or extrinsic cues. Disruption of Müller cell function was evidenced by decreased glutamine synthetase activity as well as by increased glial fibrillary acidic protein (GFAP) and decreased cellular retinaldehyde-binding protein (CRALBP) immunoreactivity. Immunocytochemistry with an antibody to CD44, which labels the microvilli of Müller cells at the outer limiting membrane, coupled with electron microscopic analysis, demonstrated that the zonulae adherentes between Müller cells and photoreceptors were either irregular or absent in areas adjacent to displaced clumps of photoreceptors. Thus AAA treatment of early post-natal mice results in localized disruption of the contacts between Müller cells and photoreceptors. These pathologic changes persist into adulthood since at P28, while short stretches of photoreceptors appeared relatively normal with fully developed outer segments, periodic clumps of displaced photoreceptor nuclei were still present adjacent to the RPE. In conclusion, Müller cell processes at the outer limiting membrane appear to play a critical role in providing a barrier to aberrant photoreceptor migration into the subretinal space.

Differential activation of Brucella-reactive CD4+ T cells by Brucella infection or immunization with antigenic extracts

In order to induce acquired cellular resistance to facultative bacterial pathogens, infection with live organisms is required. We have previously demonstrated that spleen cells from Brucella-infected mice produced gamma interferon (IFN-gamma) and interleukin-2 (IL-2) in response to Brucella antigens in vitro, while spleen cells from mice immunized with soluble Brucella proteins (SBP) produced substantial amounts of IL-2 but no detectable amount of IFN-gamma. In this study, we further analyzed the response of T cells from Brucella-infected mice and SBP-immunized mice and demonstrated that CD4(+)-enriched cells from SBP-immunized mice also produced significant amounts of IL-4, which was not detected in bulk cultures of spleen cells from infected mice. Limiting dilution analysis showed that infection resulted in a higher precursor frequency of IFN-gamma-producing CD4+ T cells and a lower precursor frequency of IL-4-producing CD4+ T cells, while immunization with SBP resulted in a higher precursor frequency of IL-4-producing cells and a very low frequency of IFN-gamma-producing cells. The precursor frequencies of IL-2-producing cells for the two groups were similar. Furthermore, IFN-gamma-producing CD4+ T cells from infected donor mice were capable of mediating resistance against challenge infection in recipient mice, but IL-4-producing CD4+ T cells from immunized mice failed to do so. These results indicate that the form of antigen has a profound influence on the outcome of the immune response. The results are discussed in light of the supposed dichotomy between Th1 and Th2 cytokine responses.

The roles of caspase-3 and bcl-2 in chemically-induced apoptosis but not necrosis of renal epithelial cells

The kidney is a target for toxicants including cisplatin and S-(1,2-dichlorovinyl)-L-cysteine (DCVC), a metabolite of the environmental contaminant, trichloroethylene. Necrosis is well characterized in kidney cells, but pathways leading to apoptosis are less clear. Cysteine conjugates are useful toxicants because they induce either necrosis or apoptosis depending on chemical structure or antioxidant status. Herein, we show that in the renal epithelial cell line LLC-PK1, activation of caspase-3 (CPP32/Yama/apopain) is crucial for apoptosis, but not necrosis. Apoptosis was blocked by zVAD.fmk, and partially by a cathepsin inhibitor. Caspase-3 activity and cleavage of poly(ADP-ribose) polymerase (PARP) was detected only during apoptosis. S-(1,1,2,2-Tetrafluoroethyl)-L-cysteine (TFEC), a metabolite of tetrafluoroethylene, kills cells only by necrosis, and did not activate caspases under any conditions. Apoptosis and activation of caspase-3 by cisplatin, but not DCVC, was prevented by bcl-2. Thus, caspase-3 activation by bcl-2-dependent and -independent mechanisms is a terminal event in chemical-apoptosis of renal epithelial cells.