Systematic review of melatonin in cerebral ischemia-reperfusion injury: critical role and therapeutic opportunities

Cerebral ischemia-reperfusion (I/R) injury is the predominant causes for the poor prognosis of ischemic stroke patients after reperfusion therapy. Currently, potent therapeutic interventions for cerebral I/R injury are still very limited. Melatonin, an endogenous hormone, was found to be valid in preventing I/R injury in a variety of organs. However, a systematic review covering all neuroprotective effects of melatonin in cerebral I/R injury has not been reported yet. Thus, we perform a comprehensive overview of the influence of melatonin on cerebral I/R injury by collecting all available literature exploring the latent effect of melatonin on cerebral I/R injury as well as ischemic stroke. In this systematic review, we outline the extensive scientific studies and summarize the beneficial functions of melatonin, including reducing infarct volume, decreasing brain edema, improving neurological functions and attenuating blood-brain barrier breakdown, as well as its key protective mechanisms on almost every aspect of cerebral I/R injury, including inhibiting oxidative stress, neuroinflammation, apoptosis, excessive autophagy, glutamate excitotoxicity and mitochondrial dysfunction. Subsequently, we also review the predictive and therapeutic implications of melatonin on ischemic stroke reported in clinical studies. We hope that our systematic review can provide the most comprehensive introduction of current advancements on melatonin in cerebral I/R injury and new insights into personalized diagnosis and treatment of ischemic stroke.

Crosstalk between oxidative stress and neutrophil response in early ischemic stroke: a comprehensive transcriptome analysis

Background

Ischemic stroke (IS) is the second leading cause of mortality worldwide, continuing to be a serious health concern. It is well known that oxidative stress and neutrophil response play vital roles in the pathophysiology of early IS. However, the complex interactions and critical genes associated with them have not been fully understood.

Methods

Two datasets (GSE37587 and GSE16561) from the Gene Expression Omnibus database were extracted and integrated as the discovery dataset. Subsequent GSVA and WGCNA approaches were used to investigate IS-specific oxidative stress-related genes (ISOSGS). Then, we explored IS-specific neutrophil-associated genes (ISNGS) using CIBERSORT analysis. Next, the protein-protein interaction network was established to ascertain candidate critical genes related with oxidative stress and neutrophil response. Furthermore, these candidate genes were validated using GSE58294 dataset and our clinical samples by RT-qPCR method. Finally, functional annotation, diagnostic capability evaluation and drug-gene interactions were performed by using GSEA analysis, ROC curves and DGIDB database.

Result

In our analysis of discovery dataset, 155 genes were determined as ISOSGS and 559 genes were defined as ISNGS. Afterward, 9 candidate genes were identified through the intersection of ISOSGS and ISNGS, PPI network construction, and filtration by degree algorithm. Then, six real critical genes, including STAT3, MMP9, AQP9, SELL, FPR1, and IRAK3, passed the validation using the GSE58294 dataset and our clinical samples. Further functional annotation analysis indicated these critical genes were associated with neutrophil response, especially neutrophil extracellular trap. Meanwhile, they had a good diagnostic performance. Lastly, 53 potential drugs targeting these genes were predicted by DGIDB database.

Conclusion

We identified 6 critical genes, STAT3, FPR1, AQP9, SELL, MMP9 and IRAK3, related to oxidative stress and neutrophil response in early IS, which may provide new insights into understanding the pathophysiological mechanism of IS. We hope our analysis could help develop novel diagnostic biomarkers and therapeutic strategies for IS.

Role of diet in stroke incidence: an umbrella review of meta-analyses of prospective observational studies

BACKGROUND

Stroke is one of the major challenges for the global healthcare system, which makes it necessary to explore the relationship between various modifiable factors and stroke risk. Recently, numerous meta-analyses of prospective observational studies have reported that dietary factors played a key role in the occurrence of stroke. However, the conclusions of previous studies have remained controversial and unclear. Accordingly, we conducted an umbrella review synthesizing and recalculating available evidence to assess the certainty of the associations between dietary factors and stroke.

METHODS

Relevant meta-analyses examining the associations between dietary factors and stroke were searched in PubMed and Embase databases up to September 1, 2021. For each eligible meta-analysis, two independent reviewers appraised the methodologic quality using the AMSTAR 2 criteria and estimated the summary effect size, 95% confidence intervals, 95% prediction intervals, heterogeneity between studies, and small-study effects. Moreover, we further assessed the associations between dietary factors and ischemic stroke as well as hemorrhagic stroke. Lastly, a set of pre-specified criteria was applied to qualitatively evaluate the epidemiological credibility of each dietary factor.

RESULTS

Overall, our umbrella review included 122 qualified meta-analyses for qualitative synthesis, involving 71 dietary factors related to food groups, foods, macronutrients, and micronutrients. Using the AMSTAR 2 criteria, 5 studies were assessed as high quality, 4 studies as moderate quality, and 113 studies as low or critically low quality. We identified 34 dietary factors associated with stroke occurrence, 25 dietary factors related to ischemic stroke, and 11 factors related to hemorrhagic stroke. Among them, high/moderate certainty epidemiological evidence demonstrated an inverse association between intake of fruits (RR: 0.90) and vegetables (RR: 0.92) and stroke incidence, but a detrimental association between red meat (RR: 1.12), especially processed red meat consumption (RR:1.17), and stroke incidence. Besides, the evidence of high/moderate certainty suggested that the intake of processed meat, fruits, coffee, tea, magnesium, and dietary fiber was associated with ischemic stroke risk, while consumption of tea, fruits, and vegetables was relevant to hemorrhagic stroke susceptibility.

CONCLUSIONS

Our study has reported that several dietary factors have a significant impact on stroke risk and offered a new insight into the relationship between dietary modification and stroke occurrence. Our results may provide an effective strategy for stroke prevention.

Control of Root Stem Cell Differentiation and Lateral Root Emergence by CLE16/17 Peptides in Arabidopsis

Secreted peptide-mediated cell-to-cell communication plays a crucial role in the development of multicellular organisms. A large number of secreted peptides have been predicated by bioinformatic approaches in plants. However, only a few of them have been functionally characterized. In this study, we show that two CLAVATA3/EMBRYO SURROUNDING REGION-RELATED (CLE) peptides CLE16/17 are required for both stem cell differentiation and lateral root (LR) emergence in Arabidopsis. We further demonstrate that the CLE16/17 peptides act through the CLAVATA1-ARABIDOPSIS CRINKLY4 (CLV1-ACR4) protein kinase complex in columella stem cell (CSC) differentiation, but not in LR emergence. Furthermore, we show that CLE16/17 promote LR emergence probably via activating the expression of HAESA/HAESA-LIKE2 (HAE/HSL2) required for cell wall remodeling. Collectively, our results reveal a CLV1-ACR4-dependent and -independent dual-function of the CLE16/17 peptides in root development.

Genetically Predicted Levels of Circulating Inflammatory Cytokines and the Risk and Age at Onset of Parkinson’s Disease: A Two-Sample Mendelian Randomization Study

Parkinson’s disease (PD) is widely considered to be a disabling neurodegenerative disorder, which has been ranked second worldwide just after Alzheimer’s disease. Until present, a wide range of studies has focused on the role of circulating inflammatory cytokines in the development of PD. However, the causal relationship between circulating inflammatory cytokines and the risk and age at the onset of PD has not been elucidated. Hence, to evaluate the effects of circulating inflammatory cytokines on the risk or age at the onset of PD more accurately, we conducted this two-sample Mendelian randomization (MR) study involving summary statistics from genome-wide association studies (GWASs). Totally, we included a GWAS for inflammatory cytokines (8,293 participants), a meta-analysis of GWASs for PD risk (482,730 participants), and a GWAS dataset for age at the onset of PD (17,996 patients with PD). A total of 149 and 131 polymorphisms for exploring relationships between 19 inflammatory cytokines and the risk and age at the onset of PD were obtained as instrumental variants. Then, we used a total of five MR methods, including inverse-variance weighted (IVW), Wald ratio, MR Egger regression, weighted median, and MR-pleiotropy residual sum and outlier (MR-PRESSO) methods. Finally, we found a causal association between circulating levels of macrophage inflammatory protein-1 beta (MIP1b) and PD risk in the IVW method (OR: 1.06; 95% CI: 1.02–1.10; P = 0.001). Meanwhile, other MR estimates by weighted median and MR-PRESSO methods yielded similar effect estimates. Besides, we identified a suggestive association of interleukin-16 (IL-16) levels with PD risk (OR: 1.08; 95% CI: 1.00–1.17; P = 0.037). For age at PD onset, there was no evidence supporting its correlation with inflammatory cytokines. Our findings implied that MIP1b and IL-16 may be novel biomarkers and promising therapeutic targets for PD development.

Genetically Predicted Circulating Concentrations of Micronutrients and Risk of Amyotrophic Lateral Sclerosis: A Mendelian Randomization Study

Amyotrophic lateral sclerosis (ALS) is a progressive and devastating neurodegenerative disease with increasing incidence and high mortality, resulting in a considerable socio-economic burden. Till now, plenty of studies have explored the potential relationship between circulating levels of various micronutrients and ALS risk. However, the observations remain equivocal and controversial. Thus, we conducted a two-sample Mendelian randomization (MR) study to investigate the causality between circulating concentrations of 9 micronutrients, including retinol, folate acid, vitamin B12, B6 and C, calcium, copper, zinc as well as magnesium, and ALS susceptibility. In our analysis, several single nucleotide polymorphisms were collected as instrumental variables from large-scale genome-wide association studies of these 9 micronutrients. Then, inverse variance weighted (IVW) approach as well as alternative MR-Egger regression, weighted median and MR-pleiotropy residual sum and outlier (MR-PRESSO) analyses were performed to evaluate causal estimates. The results from IVW analysis showed that there was no causal relationship of 9 micronutrients with ALS risk. Meanwhile, the three complementary approaches obtained similar results. Thus, our findings indicated that supplementation of these 9 micronutrients may not play a clinically effective role in preventing the occurrence of ALS.

A high stem to leaf ratio reduced rainfall use efficiency under altered rainfall patterns in a semi-arid grassland in northeast China

Rainfall use efficiency (RUE) is crucial for understanding the changes in grassland productivity due to variations in future rainfall patterns. Recently, numerous studies have been conducted on the relationship between RUE and the amount of rainfall, but there has been little research on the influence of rainfall distribution and the interactive effect of rainfall amounts and distribution on RUE. Here, a simulated rainfall experiment was conducted to evaluate the impacts of rainfall amount (average rainfall amount (R0), 334 mm; decreased (R-) and increased (R+) rainfall amounts, 233 mm and 434 mm, respectively) and dry intervals (comprising 6-day, 9-day, 12-day, 15-day, 18-day and 21-day intervals between rainfall) on productivity and RUE in Leymus chinensis (Trin.) Tzvel., a dominant grass of the Eastern Eurasian Steppe. Our results showed that (1) for biomass production and RUE, moderate extension of dry intervals was conducive to enhancing total biomass production and RUE. The peak values of total biomass and RUE appeared during the 15-day interval for R-, and the 18-day interval for R0 and R+. (2) For biomass allocation, extension of dry intervals decreased the stem to leaf ratio (S/L) and the root to shoot ratio (R/S). (3) Further, the S/L ratio was significantly negatively correlated with RUE. These results suggest that variations in rainfall patterns can alter the RUE by changing the S/L ratio, and finally influence biomass production in L. chinensis. These findings have important implications for understanding and predicting the effect of future climate change on productivity in semi-arid grassland.

Association between cheilitis granulomatosa and odontogenic infections: A case-control study

The association between cheilitis granulomatosa and dental infections (dental caries and apical periodontitis) is still not well understood. Herein, we aimed to investigate the association in large hospital cases with cohort controls. Cheilitis granulomatosa cases (n = 181) were retrieved from Peking University Hospital of Stomatology and age- and sex-matched to controls (n = 181). The χ² -test, Student's t-test, and Mann-Whitney U-test were used to compare the differences between groups. The χ² -test and odds ratio were used to verify if there was an association and risk relationship. The results showed that both dental caries and apical periodontitis were associated with cheilitis granulomatosa (p < 0.001). Individuals with cheilitis granulomatosa had approximately a twofold increased frequency of dental caries than those without cheilitis granulomatosa (104/181, 57.5% vs. 53/181, 29.3%) (p < 0.001). The odds ratio of dental caries occurring in the case group compared to the control group was 3.211. The frequency of apical periodontitis in patients with cheilitis granulomatosa was significantly greater than in those without cheilitis granulomatosa (109/181, 60.2% vs. 28/181, 15.5%) (p < 0.001). The odds ratio was 8.272. Moreover, apical periodontitis was also locationally related to cheilitis granulomatosa (p < 0.001). Collectively, our study showed that the foci of dental infections are associated with cheilitis granulomatosa, suggesting that proper treatment of focal teeth may be important in the management of cheilitis granulomatosa.

0200 Trait Mindfulness Moderates the Within-Person Relationship Between Sleep and Pain in Nurses

Introduction

Sleep and pain have a bidirectional relationship in clinical populations; however, we know less about the daily association in non-clinical but potentially vulnerable populations. Nurses are prone to poor sleep and pain symptoms due to work schedules and occupational stress. Implications from mindfulness-based interventions suggest that mindfulness may play a role in improving sleep and subsequently, reducing pain. The current study examined the within-person relationship between sleep and pain in nurses, and whether trait mindfulness moderates the relationship.

Methods

Participants were 60 nurses employed at a cancer hospital (Mage=35.35±11.83, 32% reported pain). For 14 consecutive days, ecological momentary assessment collected participants’ sleep characteristics, pain symptoms (i.e., chest pain, headaches, upset stomach, and other pain), and pain interference with daily activities. Trait mindfulness was measured using the 15-item Mindful Attention Awareness Scale. Multilevel modeling decomposed variances at the between- and within-person levels.

Results

At the between-person level, after controlling for sociodemographic covariates, more frequent insomnia symptoms (β=0.35) or lower sleep sufficiency (β=-0.19) were associated with more pain symptoms (ps&lt;.05). Inversely, individuals with more pain symptoms reported lower sleep sufficiency (β=-0.41, p&lt;.05). At the within-person level, after nights with poorer sleep quality (β=-0.08, p&lt;.01), lower sleep sufficiency (β=-0.08, p&lt;.01), or shorter sleep duration (β =-0.03, p&lt;.05), participants reported more pain symptoms the following day. There were significant interactions of mindfulness with (a) sleep sufficiency predicting pain interference and (b) sleep duration predicting number of pain symptoms, such that the adverse associations of less sufficient and shorter sleep with more pain were more apparent in those with lower mindfulness than those with higher mindfulness.

Conclusion

Although there was a bidirectional association between sleep and pain at the between-person level, sleep was more likely to be the predictor of pain at the within-person level in oncology nurses. The significant moderation by mindfulness suggest that promoting mindfulness among nurses, prone to having poor sleep and pain, may reduce the adverse impact of poor sleep on daily pain.

Support

This work was supported, in part, by the University of South Florida College of Behavioral & Community Sciences Internal Grant Program (PI: Lee, Grant No. 0134930).

0149 Nightly Sleep Characteristics are Associated with Next-Day Mindfulness

Introduction

Previous research shows that insufficient and poor sleep is associated with perceiving more stressors the following day. Sleep may also be associated with daily mindfulness, a state in which one is highly aware and focused on the present moment without evaluating or judging that moment. The association between high mindfulness and better sleep is well-established; yet, less is known about the temporal directionality between sleep and mindfulness. This study examined whether nightly sleep predicts next-day mindfulness, and vice versa.

Methods

Participants were 60 middle-aged adults working as a full-time nurse at a cancer hospital (Mage=35.35±11.83). Using ecological momentary assessments for 14 days, we asked participants about their previous night’s sleep upon waking and participants completed the 5-item state Mindful Attention Awareness Scale an average of 3 times/day. Multilevel modeling examined variance at the between- and within-person levels and tested two temporal directions simultaneously: better sleep predicting mindfulness and mindfulness predicting better sleep.

Results

Daily mindfulness, sleep duration, sleep sufficiency, and sleep quality displayed 34%, 85%, 82%, and 85% within-person variation, respectively. At the within-person level, daily mindfulness was greater on days following longer than usual sleep duration (B=0.39hrs or 23min, p&lt;.01) and greater than usual sleep sufficiency (B=0.26, p&lt;.001). The within-person link between sleep sufficiency and mindfulness remained even after controlling for the strong association of workdays with less sleep sufficiency. Conversely, mindfulness was not predictive of sleep outcomes. At the between-person level, participants who had greater sleep sufficiency and higher sleep quality overall reported greater mindfulness. These associations remained after adjusting for sociodemographics, dayshift vs. nightshift, and workdays vs. non-work days.

Conclusion

Sufficient sleep duration and perceived sleep sufficiency may be antecedents of how mindful individuals are the following day. Future analyses will test whether the daily link between sleep and mindfulness contributes to health outcomes.

Support

This work was supported, in part, by the University of South Florida College of Behavioral & Community Sciences Internal Grant Program (PI: Lee, Grant No. 0134930).

0341 Preliminary Effects of a Music Intervention on Actigraphy-Measured Sleep Among Older Adults with Dementia

Introduction

Music may benefit sleep and daytime alertness by decreasing stress, increasing attention, and potentially, slowing the progression of dementia. This study examined preliminary effects of a group-based music intervention on sleep health among older adults with dementia.

Methods

Participants were older adults with dementia living in an assisted living facility (n=9; Mage=80.11; Mrange=63−89 years). Cohort 1 (n=4) received the intervention in the morning and cohort 2 (n=5) received the intervention in the afternoon. Participants completed a 4-week intervention protocol (12 sessions) along with a one-week actigraphy sleep assessment before and after the intervention. Informed by sleep literature, we constructed a composite sleep health score encompassing Regularity, Satisfaction or quality, Alertness, Timing, Efficiency, and Duration (higher scores indicating more daily sleep problems). Using descriptive statistics and multilevel modeling, we evaluated preliminary effects of the intervention on overall sleep health and each of the sleep dimensions.

Results

Six out of nine participants exhibited a decrease in overall sleep problems at post-intervention. All 4 participants in cohort 1 showed improvement in overall sleep health at post-intervention. Specifically, in cohort 1, participants exhibited a decline in nightly sleep problems, decreased daytime nap duration, and number of naps. In contrast, while two out of five participants in cohort 2 exhibited improvement in overall sleep health, the remainder of the participants exhibited no improvement in daily sleep problems, especially in nap domains. Across cohorts, those younger in age, with vascular dementia, lower weight, and not taking sleep or hypertension related medications tended to respond better to the intervention.

Conclusion

Our preliminary results demonstrate the feasibility and potential benefit of a group-based music intervention in improving overall sleep health among older patients with dementia. Implications for conducting community-based non-pharmacological interventions to improve sleep and daytime functioning among older adults with dementia will be discussed.

Support

This work was supported, in part, by the Florida Department of Health Ed and Ethel Moore Alzheimer’s Disease Research Award (PI: Meng, Grant #9AZ28).

Effects of dietary probiotic supplementation on LXRα and CYP7α1 gene expression, liver enzyme activities and fat metabolism in ducks

1. The objective of this study was to investigate the effects of dietary probiotic supplementation on liver X receptor alpha (LXRα) and cholesterol 7α-hydroxylase (CYP7α1) mRNA levels, protein enzymatic activities and fat metabolism in Cherry Valley Pekin ducks. 2. A total of 750 one-day-old Cherry Valley Pekin ducks were randomly divided into 5 groups with three replicates of 50 ducks each in a completely randomised experiment. Each group was fed on a basal diet supplemented with 0, 500, 1000, 1500 or 2000 mg probiotics/kg. 3. Body rate and feed conversion ratio were highest and abdominal subcutaneous fat % was lowest at 1000 mg probiotic/kg. 4. The mRNA levels of LXRα and CYP7α1 in liver tissue was estimated by RT-PCR; serum triglyceride (TG) and total cholesterol (TC) concentrations were measured by ELISA. 5. The expression levels and enzyme activity of LXRα and CYP7α1 increased in conjunction with decreases in TG and TC concentrations following probiotic supplementation to a maximum at 1000 mg probiotics/kg and decreased thereafter. 6. It is concluded that dietary probiotics can enhance LXRα and CYP7α1 enzyme activities in the liver and reduce lipid concentrations and fat deposition in ducks.

Bio-inspired laminated graphite nanosheets/copper composites

Bio-inspired laminated graphite nanosheets/copper composites with modified mechanical properties.

Establish and verify TSH reference intervals using optimized statistical method by analyzing laboratory-stored data

OBJECTIVE

To establish reference intervals using an optimized statistical method by collecting available laboratory data of thyroid stimulating hormone (TSH), and then to verify with the laboratory-present reference intervals.

METHODS

TSH RIs of the total population and different races, genders, age, source of sample are established through improved Hoffmann and Katayev's method with TSH test results data from Jan 2010 to April 2012 were collected, and finally conduct comparative verification with the laboratory present RIs.

RESULTS

According to the improved method, we get various RIs of different sample populations. On comparing with the laboratory current RI (0.270-4.200 mIU/L) most reference change values (RCV) were within acceptable limits. Only lower limit of Han male, Uygur male and out-patient male populations outwith acceptable limits. On excluding the different values, finally, the new RI by the optimized statistical method is 0.233-4.979 mIU/L. Because the new RI expanded the current RI and was not different from the current RI, it was indicated that new RI could be used to verify the laboratory current RIs and seen as the current RI's confidence interval (CI).

INFERENCE

TSH RIs established by optimized Hoffmann's and Katayev's methods is viable and can be used to verify RIs provided by manufacturers or other laboratories.

Demonstration of a polymorphism in the gene ERCC1 by two DNA sequencing methods

New methodology is important to the advancement of biomedical science. We recently described a polymorphism within exon IV of the ERCC1 gene, which is associated with an approximate 50% decrease in codon usage in some biological systems. In this report we show that this polymorphism can be readily demonstrated by standard manual DNA sequencing, and by a recently developed methodology which relies on spectrophotometric principles. The major advantage of this new methodology is that several-fold more samples can be assessed per unit time, at reduced cost.

Platinum-sensitive and platinum-resistant ovarian cancer tissues show differences in the relationships between mRNA levels of p53, ERCC1 and XPA

We investigated the association between p53 mRNA expression and clinically relevant surrogates of nucleotide excision repair (ERCC1 and XPA) in 28 ovarian cancer specimens. We observed that platinum-resistant tumors showed higher mRNA levels of p53, ERCC1, and XPA than platinum-sensitive tumors; mRNA expression patterns in responders differed substantially from nonresponders; and p53 expression showed a strong correlation with the expression of ERCC1, and of XPA in platinum-sensitive tumor tissues, but not with platinum-resistant tumors. 47% of the mutations from p53 sequence analysis were not related to clinical response to chemotherapy. We conclude that the p53 influence on DNA repair in human malignancy may vary substantially from tumor to tumor, and that such differences are not necessarily related to the mutational status of p53.

Quercetin induces cell-cycle G1 arrest through elevating Cdk inhibitors p21 and p27 in human hepatoma cell line (HepG2)

Quercetin is a flavonoid ubiquitously found in nature. The therapeutic effect of quercetin on human hepatoma cell line (HepG2) was evaluated in this study. Various groups were incubated with different doses of quercetin for 12-, 24-, 48- and 72-h time duration and compared with control groups. Dose- and time-dependent inhibition in HepG2 proliferation was found with quercetin treatment. At 48 h of incubation, 61.78% of the cells were arrested at G(1) phase with 25 microM/l quercetin while 89.62% were arrested at G(1) phase with 50 microM/l quercetin. Furthermore, the results indicate that quercetin increased the content of Cdk inhibitor p21 protein, which was correlated with the elevation in p53 levels during 12 h of incubation. In addition, quercetin also increased the level of Cdk inhibitor p27 protein during 24 h of incubation. From our results it can be concluded that quercetin blocks cell cycle progression at G(1) phase and exerts its growth-inhibitory effect through the increase of Cdk inhibitors p21 and p27 and tumor suppressor p53 in HepG2.

Acousto-optic, point receiver hydrophone probe for operation up to 100 MHz

This work describes the results of initial evaluation of a wideband acousto-optic hydrophone probe designed to operate as point receiver in the frequency range up to 100 MHz. The hydrophone was implemented as a tapered fiber optic (FO) probe sensor with a tip diameter of approximately 7 microm. Such small physical dimensions of the sensor eliminate the need for spatial averaging corrections so that true pressure-time (p-t) waveforms can be faithfully recorded. The theoretical considerations that predicted the FO probe sensitivity to be equal to 4.3 mV/MPa are presented along with a brief description of the manufacturing process. The calibration results that verified the theoretically predicted sensitivity are also presented along with a brief description of the improvements being currently implemented to increase this sensitivity level by approximately 20 dB. The results of preliminary measurements indicate that the fiber optic probes will exhibit a uniform frequency response and a zero phase shift in the frequency range considered. These features might be very useful in rapid complex calibration i.e. determining both magnitude and phase response of other hydrophones by the substitution method. Also, because of their robust design and linearity, these fiber optic hydrophones could also meet the challenges posed by high intensity focused ultrasound (HIFU) and other therapeutic applications. Overall, the outcome of this work shows that when fully developed, the FO probes will be well suited for high frequency measurements of ultrasound fields and will be able to complement the data collected by the current finite aperture piezoelectric PVDF hydrophones.

Vagus nerve stimulation therapy: A research update

Over the past 5 years, and especially within the last year, there has been a rapid expansion of vagus nerve stimulation (VNS)-related preclinical research, as well as clinical studies in indications other than epilepsy. The research advances in understanding VNS are occurring in the midst of a blossoming of other forms of therapeutic brain stimulation, such as electroconvulsive therapy (ECT), transcranial magnetic stimulation (TMS), and deep brain stimulation (DBS). In general, improved understanding of the neurobiological effects of VNS therapy as a function of the different use parameters (frequency, intensity, pulse width, duration, dose) is beginning to guide clinical use and help determine which diseases, in addition to epilepsy, VNS might treat.

Signal-to-noise analysis for detection sensitivity of small absorbing heterogeneity in turbid media with single-source and dual-interfering-source

Previous studies have suggested that the phased-array detection can achieve high sensitivity in detecting and localizing inhomogeneities embedded in turbid media by illuminating with dual interfering sources. In this paper, we analyze the sensitivity of single-source and dual-interfering-source (phased array) systems with signal-to-noise ratio criteria. Analytical solutions are presented to investigate the sensitivity of detection using different degrees of absorption perturbation by varying the size and contrast of the object under similar configurations for single- and dual-source systems. The results suggest that dual-source configuration can provide higher detection sensitivity. The relation between the amplitude and phase signals for both systems is also analyzed using a vector model. The results can be helpful for optimizing the experimental design by combining the advantages of both single- and dual-source systems in object detection and localization.

[Analysis of environmental gradient and community of forest-swamp ecotone in Changbai mountains]

This paper discussed the change pattern between environmental gradients and community structure, productivity and plant diversity of forest-swamp ecotones, and the mechanism forming those community's traits, which could supply a theoretical basis for conserving and managing the biological resources of ecotonal communities. By setting up sample belts along the environmental gradients on three kinds of ecotones between forests and swamps in Changbai Mountains and through investigating initial data and establishing regression models, the authors studied the dynamic pattern of species composition, diameter class and age class of dominant species, plant diversity, community productivity of forest-swamp ecotone communities with environmental gradients. The results showed that the distribution patterns of community structure characteristics, plant diversity and community productivity were consistent with the changes of environmental gradients of forest-swamp ecotones. Along the environmental gradient from swamp to forest, the displace of dominant species happened, and the species number increased by positive exponent. The diameter distribution of trees decreased by inverse curve, and the age class of trees was suited to cubic distribution. The plant diversity increased by quadratic, and the community biomass increased by cubic power curve along the environmental gradients. The above-mentioned results suggested that the relationships between communities and environmental gradients were closely related.

Association between the level of ERCC-1 expression and the repair of cisplatin-induced DNA damage in human ovarian cancer cells

Nucleotide excision repair (NER) is responsible for the repair of platinum-DNA lesions. ERCC-1 is a critical gene within the NER pathway, and cells without a functional ERCC-1 do not repair cisplatin-caused DNA damage. The present study was therefore designed to evaluate the relationship between the expression of ERCC-1 and the repair of cisplatin-induced DNA adducts in human ovarian cancer cells in vitro. One hour exposure of MCAS cells to cisplatin yielded an approximately two-fold increment in the levels of ERCC-1 mRNA and ERCC-1 protein, as determined, respectively, by Northern and Western blottings. In addition, nuclear run-on assay showed that ERCC-1 gene transcription rate was increased to about the same extent as steady-state ERCC-1 mRNA and protein, in response to cisplatin treatment. However, the levels of ERCC-1 mRNA, ERCC-1 protein, and ERCC-1 transcript in MCAS cells are two-fold lower than those in A2780/CP70 cells, as previously reported. Furthermore, the repair of cisplatin-DNA adducts in MCAS cells, as measured by atomic absorption spectrometry, is also nearly two-fold less than that in A2780/CP70 cells, indicating a strong association between the level of ERCC-1 expression and the activity of excision repair in these two human ovarian tumor cell lines. These results suggest that ERCC-1 may be a useful marker to monitor the repair of platinum-DNA damage in tumor cells, and further highlight that potential pharmacological approaches which specifically inhibit ERCC-1 expression may increase cellular sensitivity to cisplatin.

Comparison of two human ovarian carcinoma cell lines (A2780/CP70 and MCAS) that are equally resistant to platinum, but differ at codon 118 of the ERCC1 gene

ERCC1 is an essential gene within the nucleotide excision repair process. We studied two human ovarian carcinoma cell lines for cisplatin resistance, which differed with respect to ERCC1. The A2780/CP70 cell line has been extensively studied previously, and has the wild-type ERCC1 sequence. The MCAS cell line has a recently described ERCC1 polymorphism at codon 118, which is associated with an approximate 50% reduction in codon usage. These cells did not differ with respect to p53 sequence nor p53 mRNA induction following cisplatin exposure. The induction of ERCC1 mRNA was markedly reduced in MCAS cells as compared to A2780/CP70 cells. At the IC50 cisplatin dose for each cell line, MCAS cells were less proficient at cisplatin-DNA adduct repair than A2780/CP70 cells. In absolute terms, A2780/CP70 cells repaired 3-fold as much adduct (2.7 pg/microgram DNA over 6 h vs 0.86 pg/microgram DNA); and when expressed in terms of the maximal DNA adduct load, A2780/CP70 cells repaired 50% more adduct than MCAS cells. MCAS cells had increased cytosolic inactivation of drug at the IC50 dose level, which has been previously suggested to be a compensatory cellular response for reduced DNA repair capacity. These data suggest the possibility that this specific ERCC1 polymorphism, may be associated with reduced DNA repair capacity in human ovarian cancer cells. This association may be effected through a reduction in peak production of ERCC1 mRNA, and a consequent reduction in the translation of ERCC1 mRNA into protein.

[Wetland ecosystems formation and its protection in Yellow River Delta]

Site investigation, satellite photo analysis and historic material analysis show that the vast neonatal wetlands in Yellow River Delta were created by high concentration sediment of the river and the land-sea evolution. Affected by the regional climate, landform, geological deposition, soil, vegetation and their interactions, the wetlands covered 4.5 x 10(5) hm2, 6.84 x 10(4) hm2 of which were artificial wetlands. The wetland ecosystems changed with the waving of the Yellow River Mouth and the land development in the Delta area. From ocean to land, the sublittoral aquatic wetland, eulittoral wetland, eplittoral salt wetland, bulrush-quitch wetland, meadow wetland and land agroecosystem were developed. The wetland ecosystems had abundant biological resources, including 1524 wild animals, 300 birds and 1040 fishes, which were changed recently by the oil development and affected by the interruption of Yellow River. Wetland protection should be strengthened in resources utilization.

Cisplatin and phorbol ester independently induce ERCC-1 protein in human ovarian carcinoma cells

Nucleotide excision repair (NER) is the DNA repair pathway by which cisplatin-induced damage is removed from DNA in human cells. ERCC-1 is one of the essential proteins in NER, and is essential for life. Enhanced ERCC-1 expression has been associated with clinical and cellular resistance to cisplatin. We therefore carried out this study to investigate the effect of cisplatin on ERCC-1 protein expression in A2780/CP70 human ovarian cancer cells. Western blot analysis showed that ERCC-1 protein levels were increased to more than 3 times control after a 1 h cisplatin exposure to A2780/CP70 cells in culture. This increase was time- and concentration-dependent. The effect of cisplatin was maximal at 40 mM and peaked 24-48 h after exposure to the drug. These results extend our previous observations that ERCC-1 mRNA expression is induced by cisplatin in this system. TPA, a known AP-1 activator and tumor-promoting phorbol ester, also induced ERCC-1 protein to the same extent as cisplatin, but did not synergize with cisplatin in this regard. These findings suggest that ERCC-1 gene up-regulation in these cells can result through a DNA damage-response pathway, or through the induction of AP-1 activity, independent of the occurrence of DNA damage.

Alternative splicing of ERCC1 and cisplatin-DNA adduct repair in human tumor cell lines

Alternative splicing is a common natural tool for the inhibition of function of full length gene products. We explored whether there was evidence that alternative splicing of ERCC1 may serve such a function for nucleotide excision repair. The ratio of alternatively spliced species to full length species was assessed for the protein and/or for the mRNA, for a series of human cell lines and tissues. This ratio was plotted against the amount of cisplatin-DNA adduct repair in each cell line (n=9), as measured by atomic absorbance spectrometry. As the percentage of alternatively spliced protein and/or mRNA increased, the amount of cisplatin-DNA adduct that was repaired was reduced. This inverse relationship was associated with a substantial amount of scatter (r=0.635), particularly at low levels of repair. These data demonstrate an association between alternative splicing of ERCC1, and reduction in cellular capability to repair cisplatin-DNA adduct.

A nucleotide polymorphism in ERCC1 in human ovarian cancer cell lines and tumor tissues

We studied the DNA sequence of the entire coding region of ERCC1 gene, in five cell lines established from human ovarian cancer (A2780, A2780/CP70, MCAS, OVCAR-3, SK-OV-3), 29 human ovarian cancer tumor tissue specimens, one human T-lymphocyte cell line (H9), and non-malignant human ovary tissue (NHO). Samples were assayed by PCR-SSCP and DNA sequence analyses. A silent mutation at codon 118 (site for restriction endonuclease MaeII) in exon 4 of the gene was detected in MCAS, OVCAR-3 and SK-OV-3 cells, and NHO. This mutation was a C-->T transition, that codes for the same amino acid: asparagine. This transition converts a common codon usage (AAC) to an infrequent codon usage (AAT), whereas frequency of use is reduced two-fold. This base change was associated with a detectable band shift on SSCP analysis. For the 29 ovarian cancer specimens, the same base change was observed in 15 tumor samples and was associated with the same band shift in exon 4. Cells and tumor tissue specimens that did not contain the C-->T transition, did not show the band shift in exon 4. Our data suggest that this alteration at codon 118 within the ERCC1 gene, may exist in platinum-sensitive and platinum-resistant ovarian cancer tissues.