Preparation of pH-responsive polyurethane nano micelles and their antibacterial application

Considering the differences in pH between bacterial infection microenvironment and normal tissues, a series of pH-responsive drug-release amphiphilic polyurethane copolymers (DPU-g-PEG) have been prepared in this work. Fourier transform infrared (FT-IR) spectroscopy and 1H NMR was selected to detect the structure of the condensed polymers. The DPU-g-PEG amphiphilic copolymers could form stable micelles with a hydrophilic shell of polyethylene glycol (PEG) and a hydrophobic core of polylactic acid (PLA). We loaded a model drug called triclosan onto DPU-g-PEG micelles and studied how pH affects their particle size, Zeta potential, and drug release performance. The results revealed that when exposed to acidic conditions, the surface potential of DPU-g-PEG micelles changed, the micelles' particle size increased, and the drug release performance was significantly enhanced. These results suggested that the micelles prepared in this study can release more antibacterial substances at sites of bacterial infection. Meanwhile, we also investigated the impact of different ratios of soft and hard segments on the properties of micelles, and the results showed that the pH responsiveness of micelles was strongest when the ratio of soft segments (PLLA diol + PEG 2000): 1,6-hexamethylene diisocyanate (HDI): 2,6-Bis-(2-hydroxy-ethyl)-pyrrolo[3,4-f]isoindole-1,3,5,7-tetraone (DMA) = 1: 1.2: 0.2. Furthermore, the results of inhibition zone test, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) all confirmed the antibacterial activity of triclosan-load DPU-g-PEG micelles. In conclusion, the DPU-g-PEG micelles produced in this study have the potential to be used as intelligent drug delivery systems in the biomedical field.

Latent profile analysis of psychological needs thwarting in Chinese school teachers: longitudinal associations with problematic smartphone use, psychological distress, and perceived administrative support

Introduction

In light of the significant impact that teachers have on education quality and student growth, their mental health warrants special attention. With the increasing popularity of Information and Communication Technology (ICT) and the rise of online teaching during the pandemic, teachers have become a group prone to developing problematic smartphone use (PSU). Psychological need thwarting (PNT) has been shown to be closely related to PSU, psychological distress, and perceived administrative support. However, most previous studies have adopted a variable-centered approach, which may overlook the possibility that the three basic needs are not closely associated and could form distinct profiles. Therefore, this study aims to apply latent profile analysis to identify different PNT profiles and their associations with PSU, psychological distress, and perceived administrative support.

Methods

A longitudinal survey was conducted using convenience and purposive sampling methods. The survey involved 1,642 primary and middle school teachers working in China over a two-month interval, with the first assessment in November 2021 (Time 1) and the second in January 2022 (Time 2).

Results

The results indicate that a three-profile model, intricately based on the PNT data gathered at Time 1, is most optimal: Class 1 is labeled as 'High autonomy-High competence and Moderate relatedness thwarting', Class 2 as 'High autonomy-High competence and High relatedness thwarting', and Class 3 as 'Low psychological needs thwarting'. Distinct associations were observed among the three profiles concerning PSU, psychological distress, and perceived administrative support. Specifically, in terms of PSU, the score of Class 2 was higher than Class 1, with that of Class 3 being the lowest at Time 1, while at Time 2 no significant difference was found between any two of these three groups; in terms of distress, the scores of the three profiles were arranged from high to low as Class 2, 1, and 3 at both time points; and in terms of perceived administrative support, the order was just the opposite, with 3, 1, and 2 from high to low at both Time 1 and Time 2.

Conclusion

Notably, the consistent ranking of the three classes in terms of psychological distress and administrative support suggests a lasting influence of PNT. Future studies should explore this enduring impact further by employing additional longitudinal data sets and examining potential mediators or moderators beyond the current study's scope.

The General Mattering Scale, the Anti-Mattering Scale, and the Fear of Not Mattering Inventory: Psychometric Properties and Links with Distress and Hope Among Chinese University Students

Purpose

Mattering is essential to university students' mental health. Feeling valued by others or unimportant can affect their overall well-being. However, most measures for assessing mattering have been developed and tested in Western countries, with limited evaluation of the measures when administered to university students in other regions. This study evaluated the reliability and validity of three mattering-related instruments - the General Mattering Scale (GMS), Anti-Mattering Scale (AMS), and Fear of Not Mattering Inventory (FNMI) among Chinese university students using classical test theory and Rasch analysis.

Methods

The study comprised 3594 university students from 19 universities across 13 provinces in mainland China, with a balanced gender distribution of 47.2% females and 52.8% males. Participants' ages ranged from 18 to 37, averaging 20.02 years. Most (78.4%) were in four-year programs, with the rest in three-year programs. The majority were freshmen (54.2%), and 86.3% had siblings. The predominant major was engineering (43.4%), followed by roughly equal representations in science, social science, and literature/art.

Results

The three scales showed high reliability and factorial validity, with Rasch analysis confirming their unidimensionality and monotonicity, although 2 of 15 items (one GMS item and one FNMI item) had lower fit. There were no substantial differences in item functioning between male and female respondents. Further analyses indicated that mattering, anti-mattering, and fear of not mattering all explained significant unique variance in levels of hope and distress.

Conclusion

All three mattering-related instruments are suitable for assessing Chinese students' mattering, anti-mattering, and fear of not mattering and changes in levels of these mattering dimensions. Moreover, each measure represents a unique element of the mattering construct in terms of associations with levels of hope and distress assessed in during the COVID-19 pandemic.

Psychometric properties of the Depression, Anxiety, and Stress Scale (DASS-21) among different Chinese populations: A cross-sectional and longitudinal analysis

Given that there is limited evidence concerning the psychometric properties of DASS-21 when applied to primary school students, the present study undertook a comprehensive exploration of the psychometric evidence supporting the use of the DASS-21 within this demographic. The research comprised three studies. In Study 1, the basic psychometric properties of internal consistency and construct validity were examined. A total of 3138 primary school students from three provinces in mainland China participated. The internal reliability of the overall scale was 0.93, and for all the subscales, it was higher than 0.80. Construct validity was partially supported. Both exploratory and confirmatory factor analyses upheld the factorial validity of the original three-factor structure. While convergent validity was established, the results showed unsatisfactory discriminant validity. The bifactor model showed that DASS-21 raw scores predominantly indicated the general factor, evidenced by the high explained common variance and omega-hierarchical values. However, the contributions from the three specific factors were minimal, with their omega hierarchical values all below 0.15. In Study 2, a longitudinal design was adopted, tracking 1366 primary school students from Southwest China over a three-month interval. The results further confirmed that the DASS-21 exhibited scalar time-invariance. The latent mean analysis showed that there were no statistically significant differences in the latent means of depression, anxiety, and stress between Time 1 and Time 2. In Study 3, which included 364 college students and 483 enterprise workers, the results demonstrated that the DASS-21 had measurement invariance across different populations. The latent mean analysis further confirmed that, in terms of the latent mean of all three subscales, both college students and enterprise workers had significantly higher scores than primary school students. Overall, the findings indicated that the DASS-21 is a suitable tool for screening schoolchildren for general psychological distress, but it is not suitable for discerning distinct negative mood state disorders.

[Epidemiological characteristics of mpox epidemic in Guangzhou]

Objective: To understand the epidemiological characteristics of mpox epidemic in Guangzhou and provide scientific evidence for the prevention and control of the disease. Methods: Based on the mpox surveillance system in Guangzhou, suspected mpox cases with fever and rash were reported by local hospitals at all levels to centers for disease control and prevention in Guangzhou for sampling, investigation and diagnosis. Descriptive epidemiological analysis was conducted on the clinical characteristics and treatment of the mpox cases and positive detection rate reported in Guangzhou as of 24:00 on June 23. Whole genome sequencing of the virus isolates was performed using Illumina Miniseq high-throughput sequencing platform. Results: The first mpox case in Guangzhou was reported on June 10 in 2023. As of 24:00 on June 23, a total of 25 confirmed mpox cases were reported. All the mpox cases were men with a M(Q1,Q3) of 32 (26, 36) years, the majority of the cases were MSM (96.0%). The main clinical features were rash (100.0%, 25/25), lymphadenectasis (100.0%, 25/25) and fever (52.0%, 13/25). Rash usually occurred near the genitals (88.0%, 22/25). The close contacts, mainly family members (40.4%, 23/57), showed no similar symptoms, such as fever or rash. The positive rate of mpox virus in household environment samples was 30.5%. The analyses on 3 complete gene sequences of mpox virus indicated that the strains belonged to West African type Ⅱb clade, B.1.3 lineage. Conclusions: Hidden transmission of mpox virus had occurred in MSM in Guangzhou. However, the size of affected population is relatively limited, and the possibility of wide spread of the virus is low.

Evaluating the psychometric properties of the Chinese Depression Anxiety Stress Scale for Youth (DASS-Y) and DASS-21

BACKGROUND

In recognizing the need for a reliable and valid instrument to assess psychological distress among children and adolescents, the present study translated the newly developed Depression Anxiety Stress Scale for Youth (DASS-Y) into Chinese, while also comparing its psychometric properties with those of the well-established DASS-21 within a primary and middle school demographic.

METHODS

Utilizing a combination of convenience sampling and purposive sampling, a cohort comprising 1,507 primary and 1,131 middle school students was recruited. Rasch analysis, confirmatory factor analysis (CFA), and structural equation modeling (SEM) were used in the data analysis.

RESULTS

Significant differences were observed between the DASS-Y and the DASS-21, notably within the anxiety subscale. The proportions of individuals with clinical mood disorders identified by the two scales demonstrated a significant disparity. Both scales, following an adjustment of responses, exhibited satisfactory internal consistency and convergent validity, with the acceptance of a three-factor structure. Furthermore, the DASS-Y showed superior discriminant validity relative to the DASS-21, providing more compelling evidence regarding concurrent validity.

CONCLUSION

Overall, the Chinese version of the DASS-Y demonstrated superior robustness to the DASS-21 in terms of psychometric properties. The findings provide initial evidence for the psychometric properties of the DASS-Y from another culture.

Psychometric evaluation of the depression, anxiety, and stress scale-21 (DASS-21) among Chinese primary and middle school teachers

BACKGROUND

Teachers in high-stress roles face increasing psychological distress such as anxiety and depression, underscoring the need for validated assessment instruments. Given the current absence of a comprehensive, designated, and time-efficient scale capable of evaluating depression, anxiety, and stress among the teacher population, the Depression, Anxiety, and Stress Scale-21 (DASS-21) presents itself as a promising alternative. Despite the widespread application of the DASS-21 for assessing psychological distress across various populations, its validity among teachers, along with questions about its factor structure and its potential property of time equivalence, remain unverified. This study endeavors to address these considerations by investigating the psychometric properties of the DASS-21 specifically within the population of Chinese primary and middle school teachers.

METHODS

Cross-sectional (n = 9,030) and longitudinal surveys (n = 1,642) were conducted using a non-probability sampling method. In addition to the DASS-21, the Chinese version of Chinese Teachers' Job Burnout Questionnaire (CTJBO) was utilized to evaluate the criterion validity of this scale. Three different approaches, namely confirmatory factor analysis, Rasch analysis, and network analysis, were employed to evaluate internal reliability, construct validity, as well as time invariance of the DASS-21.

RESULTS

The DASS-21 demonstrated a high degree of internal consistency (Cronbach's α > 0.85) as well as excellent convergent validity, despite poor discriminant validity as determined by average variance extracted. Confirmatory factor analysis and network analysis further supported convergent validity. The three-factor structure outperformed one- and two-factor alternatives, establishing time invariance. Rasch analysis at the item level identified six inappropriate items within the anxiety and stress subscales, which were subsequently removed. Network analysis presented a better revised network. Regression analysis with emotional exhaustion as the criterion provided logical and accurate results.

CONCLUSION

The DASS-21 was found to be a reliable and valid tool for measuring the mental health of teachers over time. To assess the instrument's psychometric properties, a combination of confirmatory factor analysis, Rasch analysis, and network analysis was utilized, which proved effective and is recommended for evaluating contentious instruments. Based on the results of the study, researchers and healthcare professionals are recommended to use the DASS-21 for assessing teachers' psychological distress. However, certain items identified in the study may need to be removed to enhance the instrument's appropriateness for this specific population.

[Clinicopathological characteristics and prognosis of patients with small bowel tumors: A single center analysis of 220 cases]

Objective: To analyze the clinicopathological characteristics and prognosis of patients with small bowel tumors. Methods: This was a retrospective, observational study. We collected clinicopathological data of patients with primary jejunal or ileal tumors who had undergone small bowel resection in the Department of Gastrointestinal Surgery, West China Hospital, Sichuan University between January 2012 and September 2017. The inclusion criteria included: (1) older than 18 years; (2) had undergone small bowel resection; (3) primary location at jejunum or ileum; (4) postoperative pathological examination confirmed malignancy or malignant potential; and (5) complete clinicopathological and follow-up data. Patients with a history of previous or other concomitant malignancies and those who had undergone exploratory laparotomy with biopsy but no resection were excluded. The clinicopathological characteristics and prognoses of included patients were analyzed. Results: The study cohort comprised 220 patients with small bowel tumors, 136 of which were classified as gastrointestinal stromal tumors (GISTs), 47 as adenocarcinomas, and 35 as lymphomas. The median follow-up for all patient was 81.0 months (75.9-86.1). GISTs frequently manifested as gastrointestinal bleeding (61.0%, 83/136) and abdominal pain (38.2%, 52/136). In the patients with GISTs, the rates of lymph node and distant metastasis were 0.7% (1/136) and 11.8% (16/136), respectively. The median follow-up time was 81.0 (75.9-86.1) months. The 3-year overall survival (OS) rate was 96.3%. Multivariate Cox regression-analysis results showed that distant metastasis was the only factor associated with OS of patients with GISTs (HR=23.639, 95% CI: 4.564-122.430, P<0.001). The main clinical manifestations of small bowel adenocarcinoma were abdominal pain (85.1%, 40/47), constipation/diarrhea (61.7%, 29/47), and weight loss (61.7%, 29/47). Rates of lymph node and distant metastasis in patients with small bowel adenocarcinoma were 53.2% (25/47) and 23.4% (11/47), respectively. The 3-year OS rate of patients with small bowel adenocarcinoma was 44.7%. Multivariate Cox regression-analysis results showed that distant metastasis (HR=4.018, 95%CI: 2.108-10.331, P<0.001) and adjuvant chemotherapy (HR=0.291, 95% CI: 0.140-0.609, P=0.001) were independently associated with OS of patients with small bowel adenocarcinoma. Small bowel lymphoma frequently manifested as abdominal pain (68.6%, 24/35) and constipation/diarrhea (31.4%, 11/35); 77.1% (27/35) of small bowel lymphomas were of B-cell origin. The 3-year OS rate of patients with small bowel lymphomas was 60.0%. T/NK cell lymphomas (HR= 6.598, 95% CI: 2.172-20.041, P<0.001) and adjuvant chemotherapy (HR=0.119, 95% CI: 0.015-0.925, P=0.042) were independently associated with OS of patients with small bowel lymphoma. Small bowel GISTs have a better prognosis than small intestinal adenocarcinomas (P<0.001) or lymphomas (P<0.001), and small bowel lymphomas have a better prognosis than small bowel adenocarcinomas (P=0.035). Conclusions: The clinical manifestations of small intestinal tumor are non-specific. Small bowel GISTs are relatively indolent and have a good prognosis, whereas adenocarcinomas and lymphomas (especially T/NK-cell lymphomas) are highly malignant and have a poor prognosis. Adjuvant chemotherapy would likely improve the prognosis of patients with small bowel adenocarcinomas or lymphomas.

Dual colorimetric and near-infrared fluorescence probe for Hg2+ detection and cell imaging

Hg²⁺ in the environment endangers human health, and a convenient monitoring method is needed for the detection of Hg²⁺. In this study, we constructed a dual colorimetric near-infrared fluorescent probe (E)-2-(3-(3-(1,3-dithian-2-yl)-4-hydroxystyryl)-5,5-dimethylcyclohex-2-en-1-ylidene)malononitrile (YF-Hg), based on the malononitrile isophorone. YF-Hg can detect Hg²⁺ rapidly and sensitively, with fluorescence emission in the near-infrared region (659 nm) with an obvious color change from violet to red in the visible light range. In addition, the low toxicity and large Stokes shift (191 nm) of YF-Hg also suggest that it is a potential tool for live-cell fluorescence imaging.

Impact of Persistent Poor Sleep Quality on Post-Stroke Anxiety and Depression: A National Prospective Clinical Registry Study

PURPOSE

The impact of poor sleep quality after stroke, especially persistent poor sleep quality, on poststroke anxiety and depression is unclear. We seek to investigate the impact of baseline and persistent poor sleep quality on short-term poststroke anxiety and depression.

PATIENTS AND METHODS

Data were analyzed for 1619 patients with acute ischemic stroke from the Impairment of Cognition and Sleep after Acute Ischemic Stroke or Transient Ischemic Attack in Chinese Patients study (ICONS). The sleep quality was assessed at 2 weeks and 3 months using the Pittsburgh Sleep Quality Index scale (PSQI). Poor sleep quality was defined as a PSQI score of >5, and persistent poor sleep quality was defined as a PSQI score of >5 at each time point. Patients were divided into three groups according to the quality of sleep: good sleep quality, baseline poor sleep quality and persistent poor sleep quality. Patient Health Questionnaire-9 (PHQ-9), General Anxiety Disorder-7 scale (GAD-7), and Modified Rankin Scale (mRS) at 3 months after stroke were taken as the study outcomes.

RESULTS

Persistent poor sleep quality was present in 70.2% of patients after stroke. Compared to those with good sleep quality, patients with baseline poor sleep quality did not show significant differences in disability, anxiety and depression. However, patients with persistent poor sleep were at increased risk of depression (odds ratio, OR 3.04, 95% confidence interval, CI 1.66-5.57, P < 0.01) and anxiety (OR 3.20, 95% CI 1.42-7.19, P < 0.01) at 3 months after stroke. Persistent poor sleep quality was not identified as a risk factor for functional disability at 3 months.

CONCLUSION

Patients with persistent poor sleep quality are at added risks for depression and anxiety after stroke.

Association Between Pre-Stroke Subjective Sleep Status and Post-Stroke Cognitive Impairment: A Nationwide Multi-Center Prospective Registry

BACKGROUND

Although sleep disorders significantly increase the risk of cognitive impairment, literature is relatively scarce regarding the impact of sleep status on cognitive function in patients with acute ischemic stroke (AIS). We seek to study the association between pre-stroke subjective sleep status and cognitive function at 3 months after stroke.

PATIENTS AND METHODS

Data were analyzed for 1,759 AIS patients from the Impairment of Cognition and Sleep after Acute Ischemic Stroke or Transient Ischemic Attack in Chinese Patients Study (ICONS). Pre-stroke subjective sleep status was assessed by the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS). Greater sleep fragmentation was defined as waking up in the middle of the night or early morning ≥3 times a week. Cognitive function was evaluated using the Montreal Cognitive Assessment (MoCA) at 3 months after stroke. Primary endpoint was the incidence of post-stroke cognitive impairment (PSCI) at 3 months after stroke. The association between subjective sleep status and PSCI was evaluated using multivariable logistic regression.

RESULTS

PSCI occurred in 52.1% at 3 months after stroke. Patients with very bad sleep quality before stroke were at increased risk of PSCI (OR, 2.11; 95% CI, 1.11-4.03; P=0.03). Subgroup analysis found that the association between very bad sleep quality and PSCI was more evident among patients with high school education or above (OR, 5.73; 95% CI, 1.92-17.10; P for interaction=0.02). In addition, patients with greater sleep fragmentation before stroke were also at higher risk of PSCI (OR, 1.55; 95% CI, 1.20-2.01; P<0.01). Similarly, subgroup analysis showed that the risk of PSCI was more pronounced among patients without employment (OR, 2.45; 95% CI, 1.59-3.77; P for interaction=0.01).

CONCLUSION

Very bad sleep quality and greater sleep fragmentation before stroke were identified as independent risk factors for PSCI at 3 months after stroke.

The Effect of Primary and Middle School Teachers' Problematic Internet Use and Fear of COVID-19 on Psychological Need Thwarting of Online Teaching and Psychological Distress

Problematic Internet use (PIU) is a risk factor for psychological distress during COVID-19, as teachers are a psychologically vulnerable population. We explored the role of PIU in terms of primary and middle school teachers' fear of COVID-19 and psychological need thwarting (PNT) of online teaching. We empirically evaluated the relationships among these research variables in explaining teachers' psychological distress during COVID-19. Online survey data were collected from 9030 teachers. A high proportion of participants demonstrated psychological distress: depression (20.4%), anxiety (26.4%), and stress (10.2%). Structural equation modeling was used to test our proposed conceptual model, wherein PIU behaviors served as predictors, mediated by fear of COVID-19 and PNT of online teaching, for teachers' psychological distress. With ideal model fit, the results of the path coefficients indicated that PIU behaviors were associated with fear of COVID-19 (p < 0.001); fear of COVID-19 and PNT of online teaching were associated with psychological distress (p < 0.001); and fear of COVID-19 was also positively associated with PNT of online teaching (p < 0.001). PSU and PSMU had an indirect positive effect on psychological distress through the mediator of fear of COVID-19 and PNT of online teaching. As such, we suggest that school administrators pay greater attention to teachers' psychological needs through efforts to enhance teachers' autonomy and relatedness from interpersonal relationships, alleviating PNT of online teaching. Our PNT of online teaching scale may also serve as a contribution for further research and practice.

Impact of Sleep Duration on Depression and Anxiety After Acute Ischemic Stroke

Background: Abnormal sleep duration predicts depression and anxiety. We seek to evaluate the impact of sleep duration before stroke on the occurrence of depression and anxiety at 3 months after acute ischemic stroke (AIS). Methods: Nationally representative samples from the Third China National Stroke Registry were used to examine cognition and sleep impairment after AIS (CNSR-III-ICONS). Based on baseline sleep duration before onset of stroke as measured by using the Pittsburgh Sleep Quality Index (PSQI), 1,446 patients were divided into four groups: >7, 6-7, 5-6, and <5 h of sleep. Patients were followed up with the General Anxiety Disorder-7 (GAD-7) and Patient Health Questionnaire-9 (PHQ-9) for 3 months. Poststroke anxiety (PSA) was defined as GAD-7 of ≥5 and poststroke depression (PSD) as PHQ-9 of ≥5. The association of sleep duration with PSA and PSD was evaluated using multivariable logistic regression. Results: The incidences of PSA and PSD were 11.2 and 17.6% at 3 months, respectively. Compared to a sleep duration of >7 h, 5-6 h, and <5 h of sleep were identified as risk factors of PSA [odds ratio (OR), 1.95; 95% confidence interval (CI), 1.24-3.07; P < 0.01 and OR, 3.41; 95% CI, 1.94-6.04; P < 0.01) and PSD (OR, 1.47; 95% CI, 1.00-2.17; P = 0.04 and OR, 3.05; 95% CI, 1.85-5.02; P < 0.01), while 6-7 h of sleep was associated with neither PSA (OR, 1.09; 95% CI, 0.71-1.67; P = 0.68) nor PSD (OR, 0.92; 95% CI, 0.64-1.30; P = 0.64). In interaction analysis, the impact of sleep duration on PSA and PSD was not affected by gender (P = 0.68 and P = 0.29, respectively). Conclusions: Sleep duration of shorter than 6 h was predictive of anxiety and depression after ischemic stroke.

Arg-Gly-Asp Peptide-Functionalized Superparamagnetic γ-Fe₂O₃ Nanoparticles Enhance Osteoblast Migration In Vitro

Making osteoblast migration manageably target to injury sites has been the key challenging in cell therapy for bone and cartilage regeneration. Superparamagnetic materials, the magnetic guide for cell migration, have been applied to increase cell retention. However, additional targeting modifications are still needed to accelerate the low uptake efficiency and moving speed. Arg-Gly-Asp peptide (RGD)-functionalized magnetic nanoparticles showed cutting-edge competence in cell differentiation control and targeted drug delivery. However, more evidence was required to corroborate its role in osteoblast migration in bone repair. In the present study, RGD-modified γ-Fe₂O₃ nanoparticles (RGD-Fe₂O₃ NPs) were prefabricated with the grafting ratio of 33.3-37.4%. The RGD-Fe₂O₃ NPs unveiled excellent water dispersibility with uniform size distribution at 5-6 nm and negligibly low cytotoxicity. As a result, MC3T3-E1 osteoblasts treated with RGD-Fe₂O₃ NPs boosted its migration speed in a magnetic field compared with those incubated with unmodified Fe₂O₃ NPs. Furthermore, osteoblasts treated with RGD-Fe₂O₃ NPs exhibited more Fe uptake. The results exposed the fact that RGD-mediated specific cellular uptake presented higher efficiency than the non-RGD-mediated one, resulting from a stronger superparamagnetic force between the labeled cells and the magnetic field. These findings indicate that the RGD-functionalized Fe₂O₃ NPs can promote osteoblast migration in the magnetic field, providing a promising strategy in magnet-guided cell therapy for bone and cartilage regeneration.

The Occurrence and Longitudinal Changes of Cognitive Impairment After Acute Ischemic Stroke

BACKGROUND AND PURPOSE

More and more evidence suggests that cognitive impairment (CI) after stroke is closely related to the quality of life of stroke patients. The primary aim of this study is to investigate the occurrence and longitudinal changes of CI at different stages after acute ischemic stroke (AIS) in Chinese patients.

METHODS

The data of this study come from the impairment of cognition and Sleep after acute ischemic stroke or transient ischemic attack in Chinese patients study (ICONS), a nationwide multicenter prospective registry that recruited consecutive AIS or transient ischemic attack in-hospital patients within 7 days after onset. Patients were followed for Montreal Cognitive Assessment (MoCA) scale at 2-week (2w), 3 months (3m) and 12 months (12m). CI was defined as MoCA score≦22. No cognitive impairment (NCI) was defined as MoCA score>22.

RESULTS

A total of 2432 AIS patients were enrolled in this study. Overall, 72.94% of patients were male and the average age was 60.95 years. Median National Institutes of Health Stroke Scale score was 3. The occurrence rate of CI was 52.38%, 35.55% and 34.16% at 2w, 3m and 12m. Among patients with CI at 2w and 3m, 39.9% and 27.9% of patients returned to NCI at next follow-up point. At 3m and 12m follow-up, there were also 9.6% and 12.7% new CI patients. The two cognitive items with the highest abnormal rate were "Delayed recall" (89.35%, 83.33% and 82.80%) and "Visuospatial/executive" (78.91%, 73.42% and 70.08%). The cognitive item with the highest percentage of improved patients was "Orientation" (60.91-76.68%), and the cognitive item with the lowest percentage of improved patients was "Language" (35.85-44.50%).

CONCLUSION

CI had a relatively high occurrence at 2w to 12m after AIS. CI at 3m and 12m was significantly lower than that at 2w after stroke. The occurrence of abnormalities and recovery probability for different cognitive items also differed greatly.

[The application of checklist in ward rounds on the prognosis of critically ill patients]

The study was to investigate whether the application of checklist during ward rounds could improve the prognosis of critical ill patients.The results suggested that the checklist used during ward rounds could not improve the inhospital mortality of critically ill patients, but it increased the proportion of deep vein thrombosis prophylaxis, and shortened prophylaxis treatment of gastric stress ulcer.

[Willingness and influencing factors related to "centralized slaughtering, fresh poultry listing and marketing" strategy among the household chefs in Guangzhou]

Objective: To study the willingness and influence factors related to "centralized slaughtering, fresh poultry listing and marketing" strategy, among the household chefs, and provide reference for government to adjust and optimize the strategy on avian influenza prevention. Methods: According to the geographical characteristics and regional functions, 6 'monitoring stations' were selected from 12 residential districts of Guangzhou, respectively. Another 21 meat markets which selling live poultry, were selected in each station and 5 household chefs of each market were invited to attend a face to face interview. Basic information, personal cognitive, willingness and influencing factors to the policy were under study. Univariate and multivariate logistic regression methods were used. Results: A total of 664 household chefs underwent the survey and results showed that the rate of support to the "centralized slaughtering, fresh poultry listing and marketing" strategy was 44.6% (296/664). Results from the multi-factor logistic regression showed that those household chefs who were males (OR=1.618, 95% CI: 1.156-2.264, P=0.005), having received higher education (OR=1.814, 95% CI: 1.296-2.539, P=0.001), or believing that the existence of live poultry stalls was related to the transmission of avian influenza (OR=1.918, 95% CI: 1.341-2.743, P<0.001) were factors at higher risk. These household chefs also intended to avoid the use of live poultry stalls (OR=1.666, 95%CI: 1.203-2.309, P=0.002) and accept the "centralized slaughtering, fresh poultry listing and marketing" strategy. Conclusion: Detailed study on this subject and, setting up pilot project in some areas as well as prioritizing the education programs for household chefs seemed helpful to the implementation of the 'freezing-fresh poultry' policy.

Unfavorable Outcome of Thrombolysis in Chinese Patients with Cardioembolic Stroke: a Prospective Cohort Study

BACKGROUND

Thrombolysis with alteplase is an effective and safe treatment for acute ischemic stroke (AIS). It is controversial whether the outcome of thrombolysis in cardioembolic stroke is different from that of other stroke subtypes. This study compares the outcomes at 3 months postthrombolysis in Chinese patients with AIS secondary to cardioembolism (CE) to the outcomes of those with large-artery atherosclerosis (LAA).

METHODS

Using the Thrombolysis Implementation and Monitoring of Acute Ischemic Stroke in China (TIMS-China) cohort, we prospectively followed 827 patients treated within 4.5 h of onset symptoms with alteplase as an intravenous thrombolytic agent. CE and LAA were defined according to TOAST criteria. We compared symptomatic intracerebral hemorrhage (SICH), mortality, and functional outcome at 3 months using multivariables logistic regression analysis.

RESULTS

In this cohort, 221 (19.6%) had CE and 606 (53.7%) had LAA. Approximately 2/3 of patients with CE had atrial fibrillation. Symptoms at onset were more severe in patients with CE than in those with LAA (NIHSS, 15.0 vs. 11.0; P < 0.0001); increased rate of SICH (5.9% vs. 0.8%; P < 0.0001); higher mortality (18.6% vs. 10.3%; P = 0.0015); and reduced functional independence (43.6% vs. 55.9%; P = 0.0018) at 3-month follow-up. After adjustment for baseline variables, the clinical outcome of patients with CE was worse than that of patients with LAA (OR, 0.62; 95% CI, 0.39 to 0.97, P = 0.0378).

CONCLUSIONS

Patients with cardioembolic stroke had more SICH after thrombolysis, and worse clinical outcome at 3-month follow-up compared with those with LAA. This emphasizes the importance of preventing cardioembolism.

Correlation between ERCC1 expression and concurrent chemotherapy and radiotherapy in patients with locally advanced nasopharyngeal cancer

In this study, the expression of DNA excision repair cross-complementing gene 1 (ERCC1) in local advanced nasopharyngeal carcinoma has been correlated with the efficacy of concurrent chemoradiotherapy. A total of 76 patients diagnosed with undifferentiated nasopharyngeal carcinoma diagnosed by nasopharyngeal biopsy and undergoing single-agent cisplatin chemotherapy (80 mg/m(2)) with concurrent radiotherapy (on the first, twenty-second, and forty-third day, 5 times per week, mean dose 74 Gy, range 70-78 Gy) at the Affiliated Cancer Hospital of Guangxi Medical University between January and December 2010 were included. After chemoradiotherapy, outcomes and long-term survival were evaluated. Immunohistochemistry was used to detect expression of ERCC1 protein in nasopharyngeal carcinoma. The relationship between the expression of ERCC1 and efficacy of concurrent chemoradiotherapy and long-term survival were analyzed. ERCC1 was expressed in 42.1% of cases. The expression of ERCC1 was correlated with T stage and clinical staging (P < 0.05), but not with gender, age, or N stage. The response rate in the ERCC1-positive and ERCC1-negative groups was 75.0% and 97.7%, respectively (P < 0.05). In the 72 cases with follow-up available, 1-, 2-, and 3-year survival rates were 91.0, 83.3, and 79.0%; they were 92.4, 87.8, 80.5%, respectively, in the ERCC1-positive group, and 87.9, 77.4, 77.4%, respectively, in the ERCC1-negative group. The expression of ERCC1 may be a sensitive prognostic indicator of concurrent chemoradiotherapy in locally advanced nasopharyngeal carcinoma.

Symptomatic intracerebral hemorrhage after intravenous thrombolysis in Chinese patients: comparison of prediction models

BACKGROUND

To assess the performance of risk scores in predicting symptomatic intracranial hemorrhage (SICH) after intravenous thrombolysis (IVT).

METHODS

A multicenter prospective study was performed in 811 patients who underwent IVT with standard-dose recombinant tissue plasminogen activator within 4.5 hours of acute ischemic stroke (AIS) onset in 67 stroke centers involved in the Thrombolysis Implementation and Monitor of acute ischemic Stroke in China program from May 2007 to April 2012. SEDAN (blood sugar, early infarct signs, [hyper]dense cerebral artery sign, age) score, Safe Implementation of Thrombolysis in Stroke (SITS)-SICH score, Glucose Race Age Sex Pressure Stroke Severity (GRASPS) score, Multicenter Stroke Survey (MSS) score, and Stroke Prognostication using Age and National Institutes of Health Stroke Scale (SPAN)-100 index were calculated in selected patients, and their predictive performance for SICH was compared according to the National Institute of Neurological Disorders and Stroke (NINDS), Safe Implementation of Thrombolysis in Stroke-Monitoring Study (SITS-MOST), and European Cooperative Acute Stroke Study (ECASS)-II criteria.

RESULTS

For predicting the risk of SICH (NINDS definition) after IVT, the area under the receiver operating characteristic (ROC) curve of MSS score was the highest (.71, P < .0001). For predicting the risk of SICH (SITS-MOST definition) after IVT, the area under the ROC curve of GRASPS score was the highest (.73, P = .005). For predicting SICH (ECASS-II definition) after IVT, the area under the ROC curve of MSS score was the highest (.73, P < .0001).

CONCLUSIONS

SITS-SICH, GRASPS, and MSS scores predicted the risk of SICH after IVT in patients with AIS, but only the latter 2 were better in the Chinese population. MSS score had the best predictive performance for SICH using NINDS and ECASS-II definitions, whereas GRASPS score was the best for SICH using the SITS-MOST definition.

Cloning, molecular characterization and expression analysis of heat shock cognate 70 (Hsc70) cDNA from turbot (Scophthalmus maximus)

As an essential member of the HSP70 family, heat shock cognate 70 (Hsc70) is a constitutively expressed molecular chaperone involved in protein metabolism. In this paper, turbot Hsc70 was cloned and the expression profile was also analyzed. The full-length cDNA of the turbot Hsc70 was 2,292 bp in length, including a 113-bp 5' UTR, a 223-bp 3' UTR and a 1,956-bp open reading frame coding a protein with 651 amino acid residues. Comparison of amino acid sequence revealed the existence of three classical HSP70 family signature motifs, a signature nonapeptide and one repeat of tetrapeptide in turbot Hsc70. The turbot Hsc70-deduced amino acids sequence exhibited 75.4-96.8 % homology with Hsp70s/Hsc70s of 24 other known sequences. In particular, the strongest homology was found with the cognate members of Hsc70 subfamily and the highest identity was found with Japanese flounder Hsc70. Semi-quantitative RT-PCR revealed that turbot Hsc70 transcripts were stably expressed in all tested tissues under normal physiological condition, while the expression levels also increased (~1.5-fold to ~threefold) after heat shock and bacterial infection. In addition, Hsc70 transcripts were detected throughout embryonic development and in turbot embryonic cell line (TEC) in the absence of any stress. Meanwhile, it was also heat inducible, but not cold inducible in TEC. These results suggest that Hsc70 gene may be involved in embryogenesis and cellular protection events under normal and stress condition.

[Effect of early-loaded small diameter implants retained mandibular overdentures on masticatory performance]

OBJECTIVE

To evaluate the clinical effect and masticatory efficiency of two early loaded Small Diameter Implants (SDI) retained mandibular overdentures.

METHODS

Eight mandibular edentulous patients received two SDIs insertion between mental foramina. The mandibular overdentures were connected with implants for early loading in the period of 2-4 weeks following implant insertion. The data of visual analogue scale (VAS) of denture satisfaction and masticatory ability were collected at baseline, two weeks, three months and six months following overdenture loading. Masticatory efficiency was evaluated before surgery and six months after overdenture loading.

RESULTS

Within the period of six months following overdenture loading, all the 16 implants remained stable. Compared with the baseline, the VAS data of denture satisfaction,stability, masticatory and poltophagy ability two weeks, three months and six months after overdenture loading were significantly improved with 30 degree (P<0.01), especially the masticatory and poltophagy ability of hard and crisp food. The value of masticatory efficiency improved considerably six months after overdenture loading (P<0.01).

CONCLUSION

Mandibular overdentures retained by two SDIs can significantly improve patients' denture satisfaction and masticatory efficiency, and provide more rational diet.

Implementation and outcome of thrombolysis with alteplase 3 to 4.5 h after acute stroke in Chinese patients

BACKGROUND AND PURPOSE

The European Cooperative Acute Stroke Study (ECASS) III showed that intravenous recombinant tissue plasminogen activator (rtPA) administered in the 3 to 4.5 h after symptom onset significantly improved clinical outcomes in patients with acute ischemic stroke (AIS). But little is known regarding the safety and efficacy of intravenous rtPA treatment within this extended time window in Chinese patients with AIS.

METHODS AND RESULTS

Data were collected from the Thrombolysis Implementation and Monitor of acute ischemic Stroke in China (TIMS-China). A total of 574 patients who underwent rtPA therapy within 4.5 h after symptom onset were included in this study: 409 in the 0- to 3-h group and 165 in the 3- to 4.5-h group. There were no significant differences in SICH rate (2.4% vs. 1.5%, P = 0.70) at 24 to 36 h, mortalities (7.5% vs. 7.3%, P = 0.84), independence rate (68.9% vs. 63.9%, P = 0.19), and excellent recovery rate (60.9% vs. 52.4%, P = 0.11) between the two time window groups. These results were comparable with previous Western studies.

CONCLUSION

This study suggests that intravenous rtPA treatment at 3 to 4.5 h of symptom onset remains safe and effective in Chinese patients with AIS.

Heterozygote genotypes at rs2222823 and rs2811712 SNP loci are associated with cerebral small vessel disease in Han Chinese population

AIMS

With developments of etiology of cerebral small vessel disease (CSVD) and genome-wide association study (GWAS) of stroke, the genetic studies of CSVD are focused on genes related to blood-brain barrier (BBB) and aging. The project aims to investigate the association between CSVD and susceptibility loci and candidate genes.

METHODS

All study subjects admitted Beijing Tiantan Hospital from June 2009 to September 2010 including 197 cerebral small vessel disease patients(S), 198 large artery atherosclerosis control individuals (vascular stenotic rate ≥50% diameter reduction) (L), 200 hypertensive intracerebral hemorrhage control individuals (H) and 197 stroke-free control individuals (C). 15 SNPs in 4 genes (MYLK, AQP4, NINJ2, and INK4/ARF) were genotyped using Multiplex Snapshot assay. Each SNP was first examined between the groups S and C in different genetic models (codominant, dominant, recessive, overdominant, and log-additive). Permutation correction was used to adjust for multiple testing. The significant SNP loci were further analyzed in comparing S with L and H, respectively. Subgroup analysis was also performed for each risk-factor category.

RESULTS

Among the 15 SNPs, rs2222823 and rs2811712 were found to be significantly associated with CSVD after multiple-testing adjustment. The heterozygote (A/T) of rs2222823 of MYLK has an odds ratio of 0.52 (95% CI =[0.35, 0.79], P= 0.002, adjusted P= 0.031) when compared with homozygotes. The heterozygote (C/T) of rs2811712 of INK4/ARF has an odds ratio of 1.75 (95% CI =[1.13-2.71], P= 0.004, adjusted P= 0.050). The SNP rs2222823 was significant (P= 0.035) in comparing S with H. In comparing S versus L, it is significant for the subgroups of patients without diabetes (P= 0.012) and drinking (P= 0.018). rs2811712 was significant in comparing S with L for the subgroups of patients with hyperlipidemia (P= 0.029) and drinking (P= 0.04).

CONCLUSION

The heterozygotes (T/A) at the rs2222823 SNP locus of MYLK gene decreases the risk of having cerebral small vessel disease, while the heterozygotes (C/T) at the rs2811712 SNP locus of INK4/ARF gene increases the risk, suggesting that the MYLK and INK4/ARF are the associated genes of cerebral small vessel disease in Han Chinese population.

Prediction of infarct core and salvageable ischemic tissue volumes by analyzing apparent diffusion coefficient without intravenous contrast material

RATIONALE AND OBJECTIVES

To investigate whether baseline apparent diffusion coefficient (ADC) maps can be employed to predict both infarct core and salvageable ischemic tissue volumes in acute ischemic stroke.

MATERIALS AND METHODS

An automated image analysis system based on baseline ADC maps was tested against 30 patients with acute ischemic stroke of anterior circulation to predict both infarct core and salvageable ischemic tissue volumes. The predicted infarct core and predicted salvageable ischemic tissue were quantitatively and qualitatively compared with follow-up imaging data in recanalization and no recanalization groups, respectively. Direct comparisons with perfusion- and diffusion- weighted magnetic resonance imaging measures were also made. Wilcoxon signed-rank test, Spearman rank correlation, and Bland-Altman plots were performed.

RESULTS

In the recanalization group, the predicted infarct core volume was significantly correlated with the final infarct volume (r = 0. 868, P < .001). In the no recanalization group, the predicted final infarct volume (sum of the predicted infarct core and salvageable ischemic tissue volumes), as well as the predicted salvageable ischemic tissue volume, was also significantly correlated with the true final infarct volume (r = 0.955, P < .001) and infarct growth (r = 0.918, P < .001), respectively. The volumes of perfusion-diffusion mismatch were significantly larger than those of infarct growth and predicted salvageable ischemic tissue. Good agreement between predicted and true final infarct lesions was visualized by Bland-Altman plots in two groups. Direct visual comparative analysis revealed good qualitative agreement between the true final infarct and predicted lesions in 21 patients.

CONCLUSION

The proposed ADC based approach may be a feasible and practical tool to predict the volumes of infarct core and salvageable ischemic tissue without intravenous contrast media-enhanced perfusion-weighted imaging at baseline.

Antithrombotic management of ischaemic stroke and transient ischaemic attack in China: a consecutive cross-sectional survey

1. Little is known about the prevention of secondary stroke in China. In the present study, we assessed the status of antithrombotic management of stroke patients in clinics across China. 2. A cross-sectional survey was conducted in 19 urban neurological clinics. All subjects diagnosed with ischaemic stroke (IS) or transient ischaemic attack (TIA) were enrolled consecutively in the study. Face-to-face interviews were conducted by research assistants using questionnaires on the day of enrollment. The data recorded included demographic and clinical characteristics, medication and reasons for not using medication. Independent predictors for the prescription of antiplatelet drugs were determined using multivariate logistic regression models. 3. Of the 2283 patients with IS or TIA enrolled in the study (34.7% women; mean ( +/- SD) age 65.8 +/- 11.6 years), 1719 (75.3%) had a prescription for antiplatelet therapy. Of the 108 patients with atrial fibrillation, only 14 (13.0%) were receiving warfarin therapy. The main independent factors significantly associated with being on antiplatelet therapy were having basic health insurance (odds ratio (OR) 1.47; 95% confidence interval (CI) 1.09-1.99), government insurance and labour insurance (OR 1.63; 95% CI 1.03-2.59) and a monthly income of > 500 yuan (US$66.70; OR 2.14; 95% CI 1.51-3.03). Being older (OR 0.70; 95% CI 0.50-0.99) and having a severe disability (OR 0.68; 95% CI 0.49-0.97) were associated with lower odds of receiving antiplatelet therapy. 4. Based on the survey results, adherence to guidelines for antithrombotic management in neurological clinics in China is poor. The main reasons contributing to the less than optimal management of stroke patients include negative attitudes among neurologists, a lack of medical insurance, a lower income and being elderly and/or severely disabled.

Can baseline magnetic resonance angiography (MRA) status become a foremost factor in selecting optimal acute stroke patients for recombinant tissue plasminogen activator (rt-PA) thrombolysis beyond 3 hours?

OBJECTIVE

We investigated whether baseline vessel status evaluated by magnetic resonance angiography (MRA) can be the foremost factor to classify acute ischemic stroke patients into subgroups for thrombolytic therapy within 3-6 hours of symptom onset.

METHODS

Acute ischemic stroke patients beyond 3 hours after symptom onset were examined by stroke magnetic resonance imaging (MRI) (diffusion- and perfusion-weighted imaging, and MRA) before and after thrombolysis treatment within 24-48 hours. Stroke MRI was used to classify acute ischemic stroke patients into subgroups and select optimal patients for thrombolytic treatment. Clinical scores were compared to determine whether there were significant differences among subgroups.

RESULTS

The difference in day 90 modified Rankin scale (mRS) between treated salvageable and untreated salvageable patients with recombinant tissue plasminogen activator (rt-PA) was remarkably statistically significant (p=0.02). Treated salvageable patients had more favorable clinical outcomes as compared with the untreated salvageable patients. Patients who did not have baseline artery occlusion were associated with more favorable clinical outcomes than untreated salvageable patients (p<0.001). The difference between treated salvageable and patients without artery occlusion in 90 day mRS score was not statistically significant (p=0.058).

CONCLUSION

Baseline vessel status evaluated by MRA may be used as the first factor ahead of mismatch to categorize acute ischemic stroke patients into subgroups. Patients who do not have initial vessel occlusion may not need thrombolytic therapy.

Global noise and oscillations in clustered excitable media

We study the effects of global noise on waves in heterogeneous, spatially clustered, reaction-diffusion systems with possible applications to calcium signaling. We first discuss how clustering of the excitability determines the dynamics by shifting bifurcation points and creating new oscillatory solutions. We then consider the specific situation, where intrinsic noise, due to the smallness of the excitable patches, destroys the global oscillatory state. We show that additional small global fluctuations, however, can partially restore temporal and spatial coherence of the oscillatory signal.

Selection of a phage-displayed peptide recognized by monoclonal antibody directed blocking the site of hepatitis C virus E2 for human CD81

The human CD81 (hCD81) molecule has been identified as a putative receptor for hepatitis C virus (HCV). HCV envelope glycoprotein 2 (E2) most likely plays a pivotal role in binding to host cells by interacting with the hCD81 molecule. In this study, a phage-displayed peptide library was used to select small peptides with anti-hCD81 monoclonal antibody JS-81. The output/input ratio of phages increased about 91 fold after the third round of selection. Eight of the 30 phage clones selected from the phage library showed specific binding to the anti-hCD81 by enzyme linked immunosorbent assay (ELISA). Competitive inhibition test further demonstrated that HCV E2 could significantly inhibit the binding of a positive phage clone to anti-hCD81 JS-81. Exogenous small peptide ATWVCGPCT contained by the positive phage clones showed aligned with the hCD81 sequence from 153-161 by sequence analyses. These results suggest that the selected ATWVCGPCT is a novel hCD81-like small peptide, which can block the binding site of HCV E2 for hCD81. It may be of further application on development of antiviral agents targeting the stage of HCV entry.

[Construction of linkage map and mapping resistance gene of Scterotinia scterotiorum in Brassica napus]

Scterotinia scterotiorum (Lib.) de by is a world-wide disease, which seriously decreases the yield and the quality of oil of rapeseed. Mapping resistance genes of S. scterotiorum is of vital effect to breed new elite cultivars resisting the disease. In this paper, we reported that a RAPD linkage map was constructed, including 193 RAPD markers, 19 linkage groups and covering 1,324 cM, by using Mapmaker 3.0. On the basis of map, and resistance genes, Sc1, Sc2 and Sc3, were located in 4th, 8th and 18th linkage groups. Among three QTLs, Sc2 has the characteristics of major gene with explained 29%. The three QTLs together explained about 56% of phenotypic variation.

Morphine inhibited respiratory burst of neutrophils and scavenged oxygen free radicals

AIM

To study the effects of morphine on active oxygen free radicals.

METHOD

Chemiluminescence method was used to measure (a) active oxygen generation induced by respiratory burst of neutrophils from human blood stimulated with phorbol myristate acetate (PMA), (b) Superoxide anion (O2.-) induced by xanthine-xanthine oxidase system, (c) hydroxyl radical (.OH) generated by ascorbic acid (AA)-Cu(2+)-zymosan, and (d) the release of H2O2.

RESULTS

The (a), (b), (c), and (d) were scavenged by morphine and their median inhibitory concentrations (IC50 and 95% confidence limits) were 21.1 (13.0-34.0), 54.1 (50.0-58.5), 224.0 (128.2-390.8), and 66.9 (62.9-71.0), nmol L-1, respectively.

CONCLUSION

The immunosuppressant effect of morphine was related to its free radicals scavenging action.

U1 snRNP can influence 3'-splice site selection as well as 5'-splice site selection

To address the mechanisms that underlie splice site selection and splice site partner assignment, we analyzed the splicing of yeast (Saccharomyces cerevisiae) transcripts containing splice site region duplications. When the 5'-splice site region was duplicated, both sites were utilized to the same extent, indicating little or no influence of proximity on 5'-splice site choice. However, the effect of a 5'-mutant site was greatly enhanced by the presence of an adjacent wild-type site, and this effect was reversed by the restoration of base-pairing with U1 snRNA. 3'-Splice site choice was apparently influenced by proximity, as the site closest to the 5'-splice site was greatly preferred. Studies with strains carrying some U1 snRNA mutations showed an increase in the use of the distal 3'-splice site, indicating a role for U1 snRNP in 3'-splice site selection. The data are compared with those from mammalian splice site choice experiments and suggest mechanisms that influence differential splice site choice as well as exon skipping.

Universally conserved and yeast-specific U1 snRNA sequences are important but not essential for U1 snRNP function

To study the contribution of the large, 568-nucleotide yeast (Saccharomyces cerevisiae) U1 snRNA to pre-mRNA splicing, we generated mutations in two regions of the molecule and introduced each mutant gene back into yeast as the sole copy of the U1 snRNA gene. We mutagenized the "A loop," a subregion highly conserved in primary sequence in all U1 snRNA molecules analyzed to date. We also mutagenized a portion of the yeast core subdomain, a region conserved in primary and secondary structure among several yeast species but absent from the much smaller metazoan U1 molecule. Surprisingly, mutations in these two regions had little or no effect on growth rate, yet several of them affected an inefficiently spliced reporter gene construct. In addition, combinations of mutants in both regions gave rise to reduced growth rates. Using the latter assay, we confirmed some of the proposed secondary structure of the yeast core domain. The experiments indicate that both regions contribute to U1 snRNP activity but that mutations in a single region do not have a substantial effect on growth rate because U1 snRNP activity is not rate-limiting for growth.

[Anti-inflammatory effect of diethylcarbamazine citrate]

Diethylcarbamazine citrate (DEC) at 180-300 mg/kg ip or 560 mg/kg ig inhibited hind paw swelling induced by sc 0.15 ml of carrageenan in normal and adrenalectomized rats. DEC ip 300 mg/kg also inhibited the same swelling induced by sc 2.5% formaldehyde in rats. The proliferation of granuloma induced by cotton-pellets tended to be inhibited by DEC, although not significantly. It inhibited the swelling of mouse ear induced by xylene and the increased vascular permeability induced by ip 0.7% HAC. DEC neither prolonged the survival time in adrenalectomized rats nor increased the weight of the adrenal or plasma cortisol levels in normal rats. DEC decreased the prostaglandin E content in inflammatory tissue, although less than the extent in the indomethacin group. These results indicate that the anti-inflammatory action of DEC is presumably due to the inhibition of synthesis or the release of prostaglandin E, in addition to a possible action mediated by its leukotriene synthesis inhibitor action.