Room-Temperature Phase Transition Material with Switchable Second-Order Nonlinear Optical Properties.

Phase transition materials with switchable second-order nonlinear optical (NLO) properties have attracted extensive attention because of their great application potential in photoelectric switches, sensors, and modulators, while metal-free organics with NLO switchability near room temperature remain scarce. Herein, we report a hydrogen-bonded metal-free organic crystal, 2-methylpropan-2-aminium 2,2-dimethylpropanoate (1), exhibiting a room-temperature phase transition and favorable NLO switchability. Through investigations on its thermal anomalies, dielectric properties, and crystal structures, we uncover that 1 holds a near-room-temperature phase transition at 303 K from noncentrosymmetric point group C2v to centrosymmetric one D2h, which is attributed to the order-disorder transformations of both tert-butylamine cations and dimethylpropionic acid anions. Accompanied by symmetry change during the phase transition, 1 exhibits reversible and repeatable NLO "on-off" switchability with a desirable switching contrast ratio of ca. 19 between high and low NLO states. This discovery demonstrates a metal-free organic crystal with NLO switching behavior near room temperature, serving as a promising candidate in smart and ecofriendly photoelectric functional materials and devices.

A Sn-Based Hybrid Ferroelastic Semiconductor with High-Temperature Dielectric Switching.

Organic-inorganic halide hybrids have been extensively developed and used in optoelectronic devices because of their superior performance such as ease of assembly, flexible structural tunability, and excellent optoelectronic properties. Ferroelastic strain might be used to modulate and control photoelectric properties such as photovoltaic voltage, while organic-inorganic hybrid ferroelastic semiconductors remain relatively unexplored. Herein, we successfully design a new Sn-base, lead-free hybrid ferroelastic semiconductor, [TPMA]2[SnCl6] (TPMA = benzyl trimethylammonium). It undergoes a high-temperature -3mF-1-type ferroelastic phase transition at 408 K, and intriguingly, its ferroelastic domains can be simultaneously switched under the stimulation of external heat and stress. The ferroelastic phase transition might be derived from the order-disorder transition of organic cations during heating and cooling. Moreover, [TPMA]2[SnCl6] also demonstrates a high-temperature dielectric switching property around 408 K, which has good stability and reproducibility. With those benefits, [TPMA]2[SnCl6] shows great potential in applications such as energy storage devices, optoelectronic devices, shape memory, intelligent switches, and so on.

Predicting cerebral white matter lesions based on the platelet-to-white blood cell ratio in hypertensive patients.

Hypertension is a common chronic disease affecting many people. White matter lesions (WMLs) are one of the imaging features of cerebrovascular disease. Predicting the possibility of developing syncretic WMLs in patients with hypertension may contribute to the early identification of serious clinical conditions. This study aims to build a model to identify patients who suffered from moderate-to-severe WMLs by using recognized WMLs risk factors including age and history of diabetes and a new factor named platelet-to-white blood cell ratio (PWR). A total of 237 patients were included in this study. The Affiliated ZhongDa Hospital of Southeast University Research Ethics Committee approved this study (Ethics No. 2019ZDSYLL189-P01). We developed a nomogram to predict the risk of syncretic WMLs in patients with hypertension using the above factors. Higher total scores on the nomogram indicated a higher risk of syncretic WMLs. This means older age, smaller PWR, and patients suffering from diabetes contributed to a greater chance for the patient to suffer from syncretic WMLs. We used a decision analysis curve(DCA) to determine the net benefit of the prediction model. The DCA we constructed showed that using our model to decide whether patients suffered from syncretic WMLs or not was better than assuming they all suffered from syncretic WMLs or all WMLs-free. As a result, the area under the curve of our model was 0.787. By integrating PWR, history of diabetes, and age, we could estimate integrated WMLs in hypertensive patients. This study provides a potential tool to identify cerebrovascular disease in patients with hypertension.

Escitalopram Alleviates Alzheimer's Disease-Type Tau Pathologies in the Aged P301L Tau Transgenic Mice.

BACKGROUND: The inhibition of tau hyperphosphorylation is one of the most promising therapeutic targets for the development of Alzheimer's disease (AD) modifying drugs. Escitalopram, a kind of selective serotonin reuptake inhibitor antidepressant, has been previously reported to ameliorate tau hyperphosphorylation in vitro. OBJECTIVE: In this study, we determined whether escitalopram alleviates tau pathologies in the aged P301L mouse. METHODS: Mice were intraperitoneal injected with either escitalopram or saline for 4 weeks, and a battery of behavioral tests were conducted before tissue collection and biochemical analyses of brain tissue with western blot and immunohistochemistry. RESULTS: Wild-type (Wt) mice statistically outperformed the aged pR5 mice in the Morris water maze, while escitalopram treatment did not significantly rescue learning and memory deficits of aged pR5 mice. Tau phosphorylation at different phosphorylation sites were enhanced in the hippocampus of aged pR5 mice, while escitalopram treatment significantly decreased tau phosphorylation. The levels of phosphorylated GSK-3ß and phosphorylated Akt were significantly decreased in the hippocampus of aged pR5 mice, while escitalopram administration markedly increased the expression level. The aged pR5 mice showed significant decreases in PSD95 and PSD93, while the administration of escitalopram significantly increased PSD95 and PSD93 to levels comparable with the Wt mice. CONCLUSION: The protective effects of escitalopram exposure during advanced AD are mainly associated with significant decrease in tau hyperphosphorylation, increased numbers of neurons, and increased synaptic protein levels, which may via activation of the Akt/GSK-3ß signaling pathway.

Fatal and Rapid Progressive Isolated Cerebral Mucormycosis Involving the Bilateral Basal Ganglia: A Case Report.

Isolated cerebral mucormycosis is a clinical type of mucormycosis that is estimated to account for 8% of all mucormycosis cases. The clinical symptoms of isolated cerebral mucormycosis are elusive, and thus conventional techniques often lake sensitivity and specificity. Moreover, cultures are often negative, even when direct microscopy examination is positive. Although histopathology will probably remain the gold standard for the diagnosis of mucormycosis, obtaining a biopsy specimen is not always feasible in most vulnerable populations. Thus, molecular approaches are currently used as an advantageous assistant examination method to improve the early identification of the causative agent and subsequently guide therapy to improve the prognosis of patients. Here, we report a case of isolated cerebral mucormycosis caused by Rhizopus microspores in a healthy young adult that was identified using next-generation sequencing technology.

Spatiotemporal analysis of hand, foot and mouth disease data using time-lag geographically-weighted regression.

Hand, Foot, and Mouth Disease (HFMD) is a common and widespread infectious disease. Previous studies have presented evidence that climate factors, including the monthly averages of temperature, relative humidity, air pressure, wind speed and Cumulative Risk (CR) all have a strong influence on the transmission of HFMD. In this paper, the monthly time-lag geographically- weighted regression model was constructed to investigate the spatiotemporal variations of effect of climate factors on HFMD occurrence in Inner Mongolia Autonomous Region, China. From the spatial and temporal perspectives, the spatial and temporal variations of effect of climate factors on HFMD incidence are described respectively. The results indicate that the effect of climate factors on HFMD incidence shows very different spatial patterns and time trends. The findings may provide not only an indepth understanding of spatiotemporal variation patterns of the effect of climate factors on HFMD occurrence, but also provide helpful evidence for making measures of HFMD prevention and control and implementing appropriate public health interventions at the county level in different seasons.

Spatial Training Ameliorates Long-Term Alzheimer's Disease-Like Pathological Deficits by Reducing NLRP3 Inflammasomes in PR5 Mice.

Recent studies have suggested that cognitive training could delay memory loss in Alzheimer's disease (AD). However, whether and how cognitive training produces long-term benefits remains unclear. Here, 10-month-old PR5 mice were spatially trained in a water maze for 4 consecutive weeks. The novel object recognition test (NORT), Western blots, Golgi staining, and ELISA were used to examine behavioral, biochemical, and pathological measures immediately after training and 3 months later. Immediately after training, we found that spatial training significantly improved cognitive performance; reduced tau neuropathology; increased the expression level of synaptophysin, PSD93, and PSD95 in the hippocampus; and increased the number of dendritic spines in PR5 mice. The expression levels of NLRP3, caspase-1, and interleukin (IL)-1ß, which were significantly elevated in PR5 mice, were reversed by spatial training. Interestingly, these effects persisted 3 months later. To further detect the role of NLRP3 in spatial training, PR5/NLRP3-/- mice and PR5/NLRP3+/- mice were also used in our study. PR5/NLRP3-/- mice showed better cognitive performance than PR5 mice. After 1 week of spatial training, these changes (including those in expression levels of synaptophysin, PSD93, and PSD95; the number of dendritic spines; and caspase-1 and IL-1ß content in PR5 mice) could be totally reversed in PR5/NLRP3-/- and PR5/NLRP3+/- mice. In addition, there was a positive correlation between NLRP3 content and the expression levels of caspase-1 and IL-1ß. These results show an important role for the NLRP3/caspase-1/IL-1ß axis in ameliorating the effect of spatial training on cognitive impairment in PR5 mice.

Escitalopram alleviates stress-induced Alzheimer's disease-like tau pathologies and cognitive deficits by reducing hypothalamic-pituitary-adrenal axis reactivity and insulin/GSK-3ß signal pathway activity.

Chronic stress, a causal factor for depression, can also cause cognitive impairments and tau pathology. However, whether and how the selective serotonin reuptake inhibitor antidepressant escitalopram ameliorates these effects are still unclear. In the present study, rats were subjected to chronic mild unpredictable stress for 8 weeks. Following the initial 4 weeks, the stressed animals were separated into susceptible (depressive) and unsusceptible (resistant) groups based on behavioral tests. Then, escitalopram (10 mg/kg i.p.) was administered for 28 days. Pathophysiological changes were assessed by performing behavioral and biochemical analyses. The results showed that both depressive and resistant rats displayed spatial memory deficits and an accumulation of tau in the hippocampus. Increased levels of corticosterone and insulin and a decreased level of glucocorticoid receptor were found in both depressive and resistant rats. We also found that activity-dependent phosphorylated insulin receptor substrate and glycogen synthase kinase-3ß (Ser9 site) were significantly decreased in both depressive and resistant rats. However, other important kinases, such as cyclin-dependent kinase 5 and mitogen-activated protein kinase kinase-1/2, did not change in our study. Furthermore, we found that the mRNA expression of tau was increased in depressive and resistant rats. No significant change in LC3B expression was found. Interestingly, almost all the pathological changes in depressive and resistant rats previously mentioned could be reversed by escitalopram. Our results suggested that escitalopram ameliorates cognitive impairments and selectively attenuates phosphorylated tau accumulation in stressed rats through the regulation of hypothalamic-pituitary-adrenal axis activity and the insulin receptor substrate/glycogen synthase kinase-3ß signaling pathway.

The excretory-secretory products of Echinococcus granulosus protoscoleces directly regulate the differentiation of B10, B17 and Th17 cells.

BACKGROUND: Excretory-secretory products (ESPs) released by helminths are well-known to regulate T cell responses in the host. However, their direct influence in the differentiation of naïve T cells, and especially B cells, remains largely unknown. This study investigated the effects of Echinococcus granulosus protoscoleces ESPs (EgPSC-ESPs) on the differentiation of IL-10-producing B cells (B10), IL-17A-producing B cells (B17) and Th17 cells. METHODS: BALB/c mice injected with EgPSC were used to evaluate the in vivo profiles of B10, B17 and Th17 cells. In vitro purified CD19+ B and naïve CD4+ T cells were cultured in the presence of native, heat-inactivated or periodate-treated EgPSC-ESPs, and the differentiation of these cell subsets were compared. RESULTS: In contrast to the control group, infected mice showed higher frequencies of B10, B17 and Th17 cells, and higher levels of IL-10 and IL-17A in the sera. Interestingly, B17 cells were first identified to express CD19+CD1dhigh. In vitro, B cells cultured with native ESPs exhibited a higher percentage of B10 cells but lower percentage of B17 and Th17 cells compared to the PBS group. Moreover, the relative expression of IL-10 and IL-17A mRNA were consistent with the altered frequencies. However, ESPs subjected to heat-inactivation or periodate treatment exhibited an inverse effect on the induction of these cell subsets. CONCLUSIONS: Our findings indicate that ESPs released by EgPSC can directly regulate the differentiation of B10, B17 and Th17 cells, which appear to be heat-labile and carbohydrate-dependent.

Citalopram Ameliorates Synaptic Plasticity Deficits in Different Cognition-Associated Brain Regions Induced by Social Isolation in Middle-Aged Rats.

Our previous experiments demonstrated that social isolation (SI) caused AD-like tau hyperphosphorylation and spatial memory deficits in middle-aged rats. However, the underlying mechanisms of SI-induced spatial memory deficits remain elusive. Middle-aged rats (10 months) were group or isolation reared for 8 weeks. Following the initial 4-week period of rearing, citalopram (10 mg/kg i.p.) was administered for 28 days. Then, pathophysiological changes were assessed by performing behavioral, biochemical, and pathological analyses. We found that SI could cause cognitive dysfunction and decrease synaptic protein (synaptophysin or PSD93) expression in different brain regions associated with cognition, such as the prefrontal cortex, dorsal hippocampus, ventral hippocampus, amygdala, and caudal putamen, but not in the entorhinal cortex or posterior cingulate. Citalopram could significantly improve learning and memory and partially restore synaptophysin or PSD93 expression in the prefrontal cortex, hippocampus, and amygdala in SI rats. Moreover, SI decreased the number of dendritic spines in the prefrontal cortex, dorsal hippocampus, and ventral hippocampus, which could be reversed by citalopram. Furthermore, SI reduced the levels of BDNF, serine-473-phosphorylated Akt (active form), and serine-9-phosphorylated GSK-3ß (inactive form) with no significant changes in the levels of total GSK-3ß and Akt in the dorsal hippocampus, but not in the posterior cingulate. Our results suggest that decreased synaptic plasticity in cognition-associated regions might contribute to SI-induced cognitive deficits, and citalopram could ameliorate these deficits by promoting synaptic plasticity mainly in the prefrontal cortex, dorsal hippocampus, and ventral hippocampus. The BDNF/Akt/GSK-3ß pathway plays an important role in regulating synaptic plasticity in SI rats.

Spatial learning and memory impairments are associated with increased neuronal activity in 5XFAD mouse as measured by manganese-enhanced magnetic resonance imaging.

Dysfunction of neuronal activity is a major and early contributor to cognitive impairment in Alzheimer's disease (AD). To investigate neuronal activity alterations at early stage of AD, we encompassed behavioral testing and in vivo manganese-enhanced magnetic resonance imaging (MEMRI) in 5XFAD mice at early ages (1-, 2-, 3- and 5-month). The 5XFAD model over-express human amyloid precursor protein (APP) and presenilin 1 (PS1) harboring five familial AD mutations, which have a high APP expression correlating with a high burden and an accelerated accumulation of the 42 amino acid species of amyloid-ß. In the Morris water maze, 5XFAD mice showed longer escape latency and poorer memory retention. In the MEMRI, 5XFAD mice showed increased signal intensity in the brain regions involved in spatial cognition, including the entorhinal cortex, the hippocampus, the retrosplenial cortex and the caudate putamen. Of note, the observed alterations in spatial cognition were associated with increased MEMRI signal intensity. These findings indicate that aberrant increased basal neuronal activity may contribute to the spatial cognitive function impairment at early stage of AD, and may further suggest the potential use of MEMRI to predict cognitive impairments. Early intervention that targets aberrant neuronal activity may be crucial to prevent cognitive impairment.

Escitalopram attenuates ß-amyloid-induced tau hyperphosphorylation in primary hippocampal neurons through the 5-HT1A receptor mediated Akt/GSK-3ß pathway.

Tau hyperphosphorylation is an important pathological feature of Alzheimer's disease (AD). To investigate whether escitalopram could inhibit amyloid-ß (Aß)-induced tau hyperphosphorylation and the underlying mechanisms, we treated the rat primary hippocampal neurons with Aß1-42 and examined the effect of escitalopram on tau hyperphosphorylation. Results showed that escitalopram decreased Aß1-42-induced tau hyperphosphorylation. In addition, escitalopram activated the Akt/GSK-3ß pathway, and the PI3K inhibitor LY294002 blocked the attenuation of tau hyperphosphorylation induced by escitalopram. Moreover, the 5-HT1A receptor agonist 8-OH-DPAT also activated the Akt/GSK-3ß pathway and decreased Aß1-42-induced tau hyperphosphorylation. Furthermore, the 5-HT1A receptor antagonist WAY-100635 blocked the activation of Akt/GSK-3ß pathway and the attenuation of tau hyperphosphorylation induced by escitalopram. Finally, escitalopram improved Aß1-42 induced impairment of neurite outgrowth and spine density, and reversed Aß1-42 induced reduction of synaptic proteins. Our results demonstrated that escitalopram attenuated Aß1-42-induced tau hyperphosphorylation in primary hippocampal neurons through the 5-HT1A receptor mediated Akt/GSK-3ß pathway.

[T Follicular Helper Cells and Related Molecules in Schistosoma japonicum Infected Mice after Praziquantel Treatment].

Objective: To investigate the pathological changes of liver and spleen of mice infected with Schistosoma japonicum and the changes of T follicular helper (Tfh) cells and surface molecules after praziquantel treatment. Methods: Fifteen female C57BL/6 mice （6-8 weeks） were randomly assigned into the praziquantel treated infection group （treated group）, infection control group (untreated group) and uninfected group （n=5 in each group）. The mice in the treated group and untreated group were each infected with 20 S. japonicum cercariae through the abdominal skin, and mice in the treated group were further administered with intragastric praziquantel [200 mg/（kg·d）] at week 6 post-infection for 3 consecutive days. Mice were sacrificed at week 4 after treatment to observe the morphological changes of liver and spleen and calculate the worm reduction rate and the liver egg reduction rate. The Tfh cell to CD4+ T cell ratio, as well as the expression of inducible T-cell costimulator （ICOS） and programmed cell death protein 1（PD-1） on peripheral blood and spleen, were determined by flow cytometry. Schistosome soluble egg antigen (SEA) specific IgG antibodies in serum were detected by ELISA. Results: The pathological changes of liver and spleen in the treated group were less severe compared with those of the untreated group, with a worm reduction rate of 84.1% and liver egg reduction rate of 69.1%. Flow cytometry showed that the percent of Tfh cells in peripheral blood and spleen was significantly higher in the treated group（14.7%-18.0%, 15.6%-25.0%） and the untreated group（13.7%-16.7%, 12.4%-18.2%） than that in the uninfected group（2.5%-6.8%, 4.9%-8.0%）, but there was no significant difference between the treated and untreated groups. The expression of ICOS in the peripheral blood and the spleen was significantly higher in untreated group（1.3%-3.2%, 4.1%-7.0%） than in the treated group（0.7%-1.1%, 1.8%-6.8%） and the uninfected group（0.2%-0.3%, 0.5%-0.8%）（P<0.01）, The expression of ICOS in the spleen was significantly higher in the treated group than in the uninfected group (P<0.01), while this difference was not found for ICOS expression in the peripheral blood. The PD-1 expression in the peripheral blood and spleen was significantly higher in the untreated group（0.8%-1.9%, 4.1%-10.7%） than in the uninfected group（0.4%-0.8%, 1.2%-1.8%）（P<0.01）, while there was no significant difference between the treated group（0.5%-1.5%, 4.5%-8.9%） and the untreated group (P>0.05). In addition, there was no significant difference in the level of SEA specific IgG between the treated group（2.015±0.061） and the untreated group（1.969±0.038） at 4 weeks after praziquantel treatment. Conclusion: Praziquantel treatment can significantly alleviate the lesions of the liver and the spleen and decrease the ICOS expression by Tfh cells in the peripheral blood and spleen.

[Serological Analysis of Antibodies against Cysticercus cellulosae and Toxoplasma gondii in 122 Patients with Meningitis Encephalitis Syndrome].

Objective: To examine the IgG and IgM antibodies for parasites Cysticercus cellulosae and Toxoplasma gondii in 122 patients with meningitis encephalitis syndrome, and provide basis for clinical diagnosis of the meningitis encephalitis syndrome. Methods: The sera were collected from patients with meningitis encephalitis syndrome in Shanghai Jiaotong University Affiliated Sixth People's Hospital, People's Hospital of Danyang City, and Jiangsu University Affiliated Hospital from August, 2014 to December, 2015. Serum IgG and IgM antibodies for cysticercus and T. gondii were examined using antibody test kits. The antibody positive rate was calculated and its distribution was analyzed by gender, season, age and occupation. Results: A total of 122 patients with meningitis encephalitis syndrome were included. Seventeen and 22 patients of them were positive for IgG （13.9%, 17/122） and IgM（18.0%, 22/122） against cysticercus, respectively, while 29 and 8 cases were positive for IgG （23.8%, 29/122） and IgM （6.6%, 8/122） against T. gondii. The positive rate of cysticercus and T. gondii in males was 30.6%（22/72） and 31.9%（23/72） respectively, while that in females was 26.0%（13/50） and 24.0% （12/50）. The positive rate of IgM against cysticercus was 12.0%（3/25）, 27.0%（17/63）, 6.9% （2/29）, and 0（0/5） from spring to winter, highest within 13-25 years（45.0%, 9/20） among age groups, and highest in workers（7/14） among various occupations. The positive rate of IgM against T. gondii was 4.0%（1/25）, 11.1% （7/63）, 0（0/29）, and 0（0/5） from spring to winter, highest in ages >65 years（44.0%, 11/25）, and highest in patients with other occupations（4/10）. There was no statistically significant difference in the positive rate between males and females, and among different seasons, ages and occupations. Conclusion: The positive rate of antibodies against cysticercus and T. gondii is high in the patients included, suggesting that a serological test for parasite infection might be performed during clinical diagnosis of meningitis encephalitis syndrome.

Escitalopram Ameliorates Tau Hyperphosphorylation and Spatial Memory Deficits Induced by Protein Kinase A Activation in Sprague Dawley Rats.

Here, we investigated the effect of escitalopram pretreatment on protein kinase A (PKA)-induced tau hyperphosphorylation and spatial memory deficits in rats using western blot and behavioral tests, respectively. We demonstrated that escitalopram effectively ameliorated tau hyperphosphorylation and the spatial memory deficits induced by PKA activation. We measured the total and activity-dependent Ser9-phosphorylated levels of glycogen synthase kinase (GSK)-3ß in hippocampal extracts. No significant change in the total level of GSK-3ß was observed between the different groups. However, compared with forskolin injection alone, pretreatment with escitalopram increased the level of Ser9-phosphorylated GSK-3ß. We also demonstrated that escitalopram increased Akt phosphorylation at Ser473 (the active form of Akt). Furthermore, we identified other important kinases and phosphatases, such as protein phosphatase 2A, extracellular signal-regulated kinases 1 and 2, and MAP kinase kinase-1/2, that have previously been reported to play a crucial role in tau phosphorylation; however, we did not detect any significant change in the activation of these kinases or phosphatases in our study. We unexpectedly demonstrated that forskolin caused anxiety-like behavior in rats, and pretreatment with escitalopram did not significantly ameliorate the anxiety-like behavior induced by forskolin. These data provide the first evidence that escitalopram ameliorates forskolin-induced tau hyperphosphorylation and spatial memory impairment in rats; these effects do not occur via the anti-anxiety activity of escitalopram but may involve the Akt/GSK-3ß signaling pathway.

Escitalopram Ameliorates Forskolin-Induced Tau Hyperphosphorylation in HEK239/tau441 Cells.

To investigate the effect of escitalopram (a widely used and highly efficacious antidepressant from the SSRI class) on tau hyperphosphorylation, HEK293/tau441 cells were pretreated with 4 µM of forskolin for 2 h. Then we treated the cells with different doses of escitalopram (0, 5, 10, 20, 40, 80 µM) for 22 h. We measured the phosphorylation level of tau by Western blotting. It was shown that escitalopram could protect tau from hyperphosphorylation induced by pharmacological activation of protein kinase A (PKA) at a dose of 20, 40, and 80 µM in vitro. Interestingly, the same dose of escitalopram could also increase the level of serine-9-phosphorylated GSK-3ß (inactive form) and the phosphorylation level of Akt at Ser473 (active form) with no significant change in the level of total GSK-3ß and Akt. Unexpectedly, 5-hydroxytryptamine 1A receptor (5-HT1A) agonist 8-OH-DPAT did not decrease forskolin-induced tau hyperphosphorylation. Our results suggest that escitalopram can ameliorate forskolin-induced tau hyperphosphorylation, which is not through the typical 5-HT1A pathway, and Akt/GSK-3ß signaling pathway is involved. These findings may support an effective role of antidepressants in the prevention of dementia associated with depression in patients.

[Expression of Cocktail DNA Vaccine Comprising Toxoplasma gondii SAGI, MIC3 and ROP2 Using Fluorescent Protein-Reporting Vectors and Evaluation of Its Immunogenicity].

OBJECTIVE: To construct a cocktail DNA vaccine that expresses multiple genes of Toxoplasma gondii and investigate its immunogenicity in mice. METHODS: Genes for surface antigens (SAG), microneme(MIC), and rhoptry protein(ROP) were amplified from genomic DNA of T. gondii and then cloned separately into eukaryotic fluorescent protein expression vectors pShuttle-CMV-MCS-EFlα-AmCyan, pLVX-IRES-Zsgreen and pLVX-IRES-rfp, to construct expression plasmids pShuttle-SAG1, pLVX-Zsgreen-MIC3 and pLVX-rfp-ROP2. 293F cells were transfected with a combination of the three plasmids using the polyethylenimine (PEI) method. Forty-eight hours later, the expression of the three genes was observed under a fluorescence microscope. In addition, 30 C57BL/6 mice were randomized to receive intramuscular injection of saline (50 pA, group A), pShuttle+pLVX-Zsgreen+pLVX-rfp empty plasmids(2 µg/µL, 17 µL of each, group B) and pShuttle-SAG1+pLVX-Zsgreen-MIC3+ pLVX-rfp-ROP2 recombinant plasmid (2 µg/µL, 17 µL of each, group C). After 28 days, anti-T. gondii antibody in mouse serum was detected by ELISA, to evaluate the immunogenicity of the vaccine. RESULTS: The SAG1, MIC3 and ROP2 genes were amplified from the genomic DNA, with product sizes of 1, 1.1 and 1.7 kb. The eukaryotic expression plasmids pShuttle-SAG1, pLVX-Zsgreen-MIC3 and pLVX-rfp-ROP2 were constructed, and the corresponding fluorescences (blue, green and red) were observed after transfection. On day 28 after mouse vaccination, ELISA showed that the mean A(450) values for serum IgG in groups A, B and C were (0.620±0.029), (0.741±0.040) and (1.561±0.131), respectively, with the group C value being significantly higher than the others (P<0.01). CONCLUSION: The cocktail DNA vaccine comprising T. gondii SAG1, MIC3 and ROP2 shows promising immunogenicity in mice, and the fluorescent protein expression vectors are reliable tools for expression of the target genes.

Citalopram attenuates tau hyperphosphorylation and spatial memory deficit induced by social isolation rearing in middle-aged rats.

Social isolation (SI) is considered as a chronic stress. Here, middle-aged rats (8 months) were group or isolation reared for 6 weeks. Following the initial two-week period of rearing, citalopram (10 mg/kg i.p.) was administered for 28 days. Changes in recognition memory, depression and anxiety-like behavior, and phosphorylated tau were investigated. We found that SI did not lead to obvious depression/anxiety-like behavior in middle-aged rats. Memory deficits and increased tau hyperphosphorylation at Tau-1, Ser396 episodes could be almost reversed by citalopram. The level of Ser9-phosphorylated GSK-3ß (inactive form) was significantly decreased in the SI group which also could be almost reversed by citalopram, suggesting that the citalopram could prevent GSK-3ß from SI-induced overactivation. The melatonin level was decreased in SI group compared with group housed (GH) group, and citalopram could partly restore the level of melatonin. We also found that citalopram could increase MT1 and MT2 in mRNA level. Our results demonstrate that citalopram increases the level of melatonin which negatively regulates GSK-3ß and attenuates tau hyperphosphorylation and spatial memory deficit induced by SI in middle-aged rats. Suggesting that SI might constitute a risk factor for Alzheimer's disease (AD), and citalopram may represent a therapeutic strategy for the treatment of AD.

[Accumulation of myeloid-derived suppressor cells in the spleen and peripheral blood of Schistosoma japonicum-infected mice].

OBJECTIVE: To determine the accumulation of CD11b+ Gr-1+ myeloid-derived suppressor cells (MDSC) in Schistosorna japonicum-infected mice. METHODS: Twenty-four C57BL/6 mice were infected cutaneously with S. japonicum cercariae. Peripheral blood samples were collected at 1, 2, 6 and 8 weeks post-infection (6 mice for each group). At 6 and 8 weeks post-infection, spleens were removed and a single-cell suspension was prepared. At the same time, 6 healthy mice each served as control. During the different stages of infection, the levels of MDSC, Gr-1+ cells, CD11b+ cells in murine peripheral blood and spleen were detected by flow cytometry. The possible function of MDSC on T cells was evaluated by using a CCK-8 method and CFSE proliferation assay. RESULTS: At 6 and 8 weeks post-infection, the levels of MDSC (38.2%-57.8% and 47.1-77.6%, respectively), Gr-1+ cells (28.9%-44.6%, 40.4%-72.9%), and CD11b+ cells (36.0%-48.1%, 40.3%-68.3%) in infection group were significantly higher than that of the controls (15.1%-20.4%, 8.4%-17.3%, 9.8%-22.6%), and that of infection group at 1 week (16.2%-19.8%, 13.0%-16.8%, 17.6%-19.4%) and 2 weeks (19.8%-29.5%, 17.2%-22.2%, 20.9%-33.3%) post-infection (P < 0.01). No significant difference was found in the levels of MDSC, Gr-1+ cells, CD11b+ cells among infection group at 1 and 2 weeks post-infection and control group. Moreover, the fluctuation trends of these cells in the spleens of infected mice were similar to those cells in peripheral blood (P > 0.05). Strikingly, the proliferation index of normal CD4 T cells was significantly lower after co-culture with Gr-1+ cells isolated from infected mice. CONCLUSION: Schistosoma japonicum infection induces higher level of MDSC in mice, and Gr-1+ cells isolated from the infected mice can significantly inhibit the proliferation of the normal CD4+ T cells.