Gramine protects against pressure overload-induced pathological cardiac hypertrophy through Runx1-TGFBR1 signaling.

BACKGROUND: Gramine, also named 3-(N,N-dimethylaminomethyl) indole, is a indole alkaloid. It is mainly extracted from various natural raw plants. Despite being the simplest 3-aminomethylindole, Gramine has broad pharmaceutical and therapeutic effects, such as vasodilatation, antioxidation, mitochondrial bioenergetics-related effects, and angiogenesis via modulation of TGFß signaling. However, there is little information available about Gramine's role in heart disease, especially pathological cardiac hypertrophy. PURPOSE: To investigate Gramine's effect on pathological cardiac hypertrophy and clarify the mechanisms behind its action. METHODS: In the in vitro experiment, Gramine (25 µM or 50 µM) was used to investigate its role in Angiotensin II-induced primary neonatal rat cardiomyocytes (NRCMs) hypertrophy. In the in vivo experiment, Gramine (50 mg/kg or 100 mg/kg) was administrated to investigate its role in transverse aortic constriction (TAC) surgery mice. Additionally, we explored the mechanisms underlying these roles through Western blot, Real-time PCR, genome-wide transcriptomic analysis, chromatin immunoprecipitation and molecular docking studies. RESULTS: The in vitro data demonstrated that Gramine treatment obviously improved primary cardiomyocyte hypertrophy induced by Angiotensin II, but had few effects on the activation of fibroblasts. The in vivo experiments indicated that Gramine significantly mitigated TAC-induced myocardial hypertrophy, interstitial fibrosis and cardiac dysfunction. Mechanistically, RNA sequencing and further bioinformatics analysis demonstrated that transforming growth factor ß (TGFß)-related signaling pathway was enriched significantly and preferentially in Gramine-treated mice as opposed to vehicle-treated mice during pathological cardiac hypertrophy. Moreover, this cardio-protection of Gramine was found to mainly involved in TGFß receptor 1 (TGFBR1)- TGFß activated kinase 1 (TAK1)-p38 MAPK signal cascade. Further exploration showed that Gramine restrained the up-regulation of TGFBR1 by binding to Runt-related transcription factor 1 (Runx1), thereby alleviating pathological cardiac hypertrophy. CONCLUSION: Our findings provided a substantial body of evidence that Gramine possessed a potential druggability in pathological cardiac hypertrophy via suppressing the TGFBR1-TAK1-p38 MAPK signaling axis through interaction with transcription factor Runx1.

Prospects for the application of traditional Chinese medicine network pharmacology in food science research.

There has always been a particular difficulty with in-depth research on the mechanisms of food nutrition and bioactivity. The main function of food is to meet the nutritional needs of the human body, rather than to exert a therapeutic effect. Its relatively modest biological activity makes it difficult to study from the perspective of general pharmacological models. With the popularity of functional foods and the concept of dietary therapy, and the development of information and multi-omics technology in food research, research into these mechanisms is moving towards a more microscopic future. Network pharmacology has accumulated nearly 20 years of research experience in traditional Chinese medicine (TCM), and there has been no shortage of work from this perspective on the medicinal functions of food. Given the similarity between the concept of 'multi-component-multi-target' properties of food and TCM, we think that network pharmacology is applicable to the study of the complex mechanisms of food. Here we review the development of network pharmacology, summarize its application to 'medicine and food homology', and propose a methodology based on food characteristics for the first time, demonstrating its feasibility for food research. © 2023 Society of Chemical Industry.

Impacts of microplastic-petroleum pollution on nutrient uptake, growth, and antioxidative activity of Chlorella vulgaris.

As one of the emerging pollutants, microplastics (MPs; <5 mm) can interact with co-contaminants such as petroleum in marine aquatic systems, and their combined toxicity has not been fully investigated. Therefore, this study focused on pollutants such as micro-sized polyethylene (mPE) and petroleum, aiming to explore their single and combined toxicities to microalga Chlorella vulgaris in terms of the cell growth, antioxidative enzymes, and nutrients utilization. The results showed that the MPs alone (particle sizes (i.e., 13, 165, 550 µm), concentrations (i.e., 0.01, 0.1, and 1 g/L), and aging degrees (i.e., aged for 0 d and 90 d under UVA)), and petroleum alone (5% water accommodated fraction, WAF), and their combinations (i.e., 5% WAF + 165 µm-0.1 g/L-aged 0 d mPE, 5% WAF + 165 µm-0.1 g/L-aged 90 d mPE) all posed toxicities risk to C. vulgaris, following an increase in oxidative stress. The cellular utilization of elements such as Fe, Si, Ca, and Mg was inhibited, whereas the uptake of Mn, NO3--N, and PO43--P increased as compared to the control experiments. Furthermore, the relationship between nutrients and growth indicators was analyzed using a structural equation model. The results indicated that Fe and Mn directly affected the indirect NO3--N absorption by C. vulgaris, which indirectly affected the dry cell weight (DCW) of the microalgae. The path coefficient of Fe and Mn affecting nitrate was 0.399 and 0.388, respectively. The absorption of N was the key step for C. vulgaris resist stress. This study provides a novel analysis of the effects of MPs on the growth of microalgae from the perspective of nutrient elements, thereby providing a useful basis for further exploration of the associated mechanisms.

Elucidating the negatively influential and potentially toxic mechanism of single and combined micro-sized polyethylene and petroleum to Chlorella vulgaris at the cellular and molecular levels.

Although microplastics (MPs; <5 mm) may interact with co-contaminants (e.g., petroleum) in marine aquatic systems, little is known about their combined toxicity. Therefore, this study explored the toxicities and their mechanisms of micro-sized polyethylene (mPE) and their combination with petroleum to Chlorella vulgaris. The single MPs at various particle sizes, concentrations, and aging degree, single petroleum, and their combinations, were found to pose toxicities to C. vulgaris. This study also found the microcosm's microbial diversity changed. The microbial communities in the C. vulgaris biotopes were altered under exposure to mPE and petroleum, and were disturbed by external factors such as MPs particle size, concentration, aging time, and the combination with petroleum. Furthermore, as compared with the toxicity of petroleum on microalgal transcriptional function, mPE caused less toxic to C. vulgaris, and only impact the posttranslational modification, protein turnover, and signal transduction processes. Most importantly, mPE reduced petroleum toxicity in C. vulgaris via regulating the ABC transporter, eukaryotic ribosome synthesis, and the citrate cycle metabolic pathways. Overall, our findings could fundamentally provide insights into the joint ecotoxicological effects of MPs and petroleum, and highlight the potential risks of co-exsiting pollutants.

Occurrence and spatial distribution of microplastics, and their correlation with petroleum in coastal waters of Hainan Island, China.

In this study, the distribution, abundance, morphology, and composition of microplastics (MPs) in surface seawater and sediment of Hainan Island were systematically investigated. Seawater and sediment samples were collected from six functional zones, including harbor, industrial district, sparsely populated area, tourist area, residential area, and aquaculture area. The abundance of MPs in seawater was 0.46-19.32 items/L, with an average of 2.59 ± 0.43 items/L, which were similar to those detected in the South China Sea (e.g., Nansha (1.25-3.20 items/L) and Xisha (2.57 ± 1.78 items/L)). The highest level was detected in Qinglan Bay Estuary, and the lowest was in Sanya West Island. The abundance of MPs in sediment was 41.18-750.63 items/kg, with an average of 372.47 ± 62.10 items/kg; the highest concentration was detected at Tanmen Port, and the lowest was in Lingao sea area. It was detected that the MPs with smaller size exhibited a higher concentration in seawater. MPs were commonly black and white, and predominantly linear and fragmented in shape. Polyethylene terephthalate (PET) was the dominant polymer, which might be derived from laundry wastewater. The petroleum concentration was 0.02-0.21 mg/L in the investigated area, with harbors being the most severely polluted areas. Furthermore, this study also found that MPs pollution was positively correlated with petroleum in seawater, indicating similarities between MPs and petroleum-based sources of pollution. This study identifies the contamination and characteristics of MPs and their correlation with petroleum in Hainan Island, the biggest island in the South China Sea, providing important data for further research on protecting marine ecosystems.

Sorption behaviors of petroleum on micro-sized polyethylene aging for different time in seawater.

Microplastics (MPs; <5 mm) and oil pollution have been receiving global attention. To date, the adsorption mechanism of petroleum by MPs is largely unknown. This study investigated the adsorption of petroleum on micro-sized polyethylene (mPE) undergoing aging (days 0, 15, 30, 90 and 180). The petroleum adsorption capacity of mPE was further assessed at varying pH (2, 5, 7.32, 10 and 12), temperature (4, 15, 25, 45 and 65 °C) and in presence of coexisting pollutants (Cu, bisphenol A (BPA) and petroleum). The results indicated that the adsorption capacity of mPE increased with the prolonged aging time and smaller-sized particles, while the adsorption capacity of the 550 and 165 µm mPE undergoing aging increased by 12.7%-50.9% and 22.1%-63.9%, respectively. The adsorption kinetics and isotherm model of mPE on petroleum were well fitted by pseudo-second order, intraparticle diffusion, Freundlich and Langmuir models, showing the sorption behavior was controlled by the diffusion of pores, liquid film diffusion, and surface adsorption. The petroleum adsorption capacity of mPE was predominant affected by surface roughness, specific surface area, hydrophobicity, oxidation functional groups, adsorption sites, hydrogen bonds, while zeta potential and crystallinity may not be the crucial factors. Likewise, temperature and pH may influence the characteristics of petroleum, and further result in a decreasing adsorption capacity of mPE to petroleum. The highest adsorption capacity of mPE to petroleum was reached at pH 7.32 and 25 °C. The coexisting Cu, BPA and petroleum competed for adsorption sites on the surface of mPE. These findings could fundamentally provide new insights for environmental risk assessment of MPs, particularly for the specific location like harbor which is commonly rich in MPs and petroleum simultaneously.

Controllable silicon nanostructures featuring stable fluorescence and intrinsic in vitro and in vivo anti-cancer activity.

In this manuscript, we demonstrate that the in situ growth of fluorescent silicon (Si) nanomaterials is stimulated when organosilicane molecules interact with different green teas, producing multifunctional Si nanomaterials with controllable zero- (e.g., nanoparticles), two- (e.g., nanosheets), and three- (e.g., nanospheres) dimensional nanostructures. Such green tea-originated Si nanomaterials (GTSN) exhibit strong fluorescence (quantum yield: ∼19-30%) coupled with ultrahigh photostability, as well as intrinsic anti-cancer activity with high specificity (e.g., the GTSN can accurately kill various cancer cells, rather than normal cells). Taking advantage of these unique merits, we further performed systematic in vitro and in vivo experiments to interrogate the mechanism of the green tea- and GTSN-related cancer prevention. Typically, we found that the GTSN entered the cell nuclei and induced cell apoptosis/death of cancer cells. The prepared GTSN were observed in vivo to accumulate in the tumour tissues after 14-d post-injection, leading to an efficient inhibition of tumour growth. Our results open new avenues for designing novel multifunctional and side-effect-free Si nanomaterials with controllable structures.

[Core prescription excavation of launched Chinese patent medicines for treating different syndromes of angina pectoris].

To analyze the medication features and regularity of prescriptions of traditional Chinese medicines in treating patients with coronary heart disease angina pectoris based on the launched Chinese patent medicines. In the article,we collected all of the launched Chinese patent medicines for treating coronary heart disease and angina pectoris from the Chinese patent medicine value assessment information database,and set up a medical record normalized database,then carried out the classification of syndromes. The medication features and prescription rules for angina pectoris were analyzed by frequency statistics and association rules(IBM SPSS Modeler 14. 1 Premiums software,Apriori algorithm). Finally,a total of 170 prescriptions were selected,and 197 Chinese herbs were included,involving to totally 11 syndrome types,in which blood stasis syndrome,Qi stagnation and blood stasis syndrome,Qi deficiency and blood stasis syndrome,Qi-Yin deficiency and blood stasis syndrome were the main syndrome types. The frequency of single-herb medicines for the four main syndrome types,the combination of commonly used medicines,and the core prescriptions were summarized. After comparing the core prescriptions of the four syndrome types,we could analyze the medication features and prescription rules. In conclusion,the therapeutic principle is blood-activating and stasis-dissolving,and consideration was also given to promoting Qi,invigorating Qi and resuscitation and invigorating Qi-Yin. The main medicines include Danshen(Salvia Miltiorrhizae Radix et Rhizoma) and Chuan-xiong(Chuanxiong Rhizoma). According to different types of syndromes,Chinese herbal medicines are added,such as Jiangxiang(Dalbergiae Odoriferae Lignum), Chishao(Paeoniaeradix Rubra), Sanqi(Notoginseng Radix et Rhizoma), Honghua(Carthami Flos),Bingpian(Borneolum Syntheticum),Renshen(Ginseng Radix et Rhizoma). Frequency statistics and association rules are combined to explore the medication features and core prescriptions,which provide ideas for the treatment of angina pectoris and the development of new drugs.

Multifunctional Silicon-Carbon Nanohybrids Simultaneously Featuring Bright Fluorescence, High Antibacterial and Wound Healing Activity.

In this work, a class of multifunctional silicon-carbon nanohybrids (designated as SiCNs), which simultaneously possess aqueous dispersibility, bright fluorescence (photoluminescence quantum yield [PLQY]: ≈28%), as well as high antibacterial and wound healing activity, is presented. Taking advantage of these unique merits, cell distribution and pharmacological behavior of the SiCNs is first investigated through tracking their strong and stable fluorescence. The high bacteria inhibition ability (≈82.9% killing rate toward S. aureus) and hemostatic effects (shorten the bleeding time from ≈60 to ≈15 s) of the resultant SiCNs are then demonstrated. Moreover, the wound closure promotion activity (10% lead in wound contraction) is systematically demonstrated in vivo, which is especially suitable for wound healing applications. The results suggest the SiCNs as a new kind of high-performance multifunctional nanoagents suitable for various biological and biomedical utilizations.

Considerations for the Quality Control of Newly Registered Traditional Chinese Medicine in China: A Review.

Background: The quality control of traditional Chinese medicine (TCM) has been essential for the development of TCM industry. In recent years, with the acceleration of TCM modernization, research on the quality control of TCM has reached a higher level. Objective: This article suggested a comprehensive approach to the quality control of TCM and proposed specific requirements for the quality control of newly registered TCM in various phases of development. Method: The views in this article are mainly derived from the laws and regulations of China and the authors' experiences. Results: It pointed out that the investigation on the quality control of TCM should be led by Chinese traditional medicine theory and guided by the clinical value. Moreover, it should follow the basic principle of "quality by design" and in-process control to establish a quality control system that embodies the characteristics of TCM and accurately reflects the safety, efficacy, and quality consistency. Given that TCM is a natural resource-dependent industry, the quality control of TCM should also focus on the protection and sustainable use of resources. Conclusions: TCM quality control should organically combine Chinese traditional medicine theory with modern science and technology, be guided by clinical value, pay attention to the protection and sustainable use of resources, fully embody the characteristics of quality by design (QbD) and in-process quality control, and gradually establish a quality control system in accordance with the features of Chinese traditional medicine. Highlights: The article has guiding significance for the research and development of newly registered TCM.

[Absorption enhancing effects and safety of PAMAM dendrimers on liquiritin].

PAMAM dendrimer is one of the most widely studied dendrimers in recent years, which has a large number of functional groups on the surface and cavities inside, specific three-dimensional structure and good biocompatibility, permeability and stability. It has been widely applied in drug and gene carrier fields and may become a new absorption enhancer. In order to study the absorption enhancing effects of PAMAM dendrimers, liquiritin was selected as the model drug, with the protection of spleen and liver, detoxification and other functions, but it had not been widely used in clinical application because of its difficult absorption, first pass effect, and low bioavailability. This topic was based on the two main determinants (solubility and permeability) of intestinal absorption in the body, researched the physicochemical properties of liquiritin, analyzed the transport volume of liquiritin with or without PAMAM dendrimers by using Caco-2 cell model, and analyzed the cytotoxicity of PAMAM dendrimers on Caco-2 cells by MTT experiments. These results showed that 0.1% of the G4 generation PAG can promote the absorption of liquiritin safely and effectively, and it was suitable for further development into a new type of pharmaceutical excipients.

Reusable Silicon-Based Surface-Enhanced Raman Scattering Ratiometric Aptasensor with High Sensitivity, Specificity, and Reproducibility.

Rapid, sensitive, and accurate detection of adenosine triphosphate (ATP), the primary energy molecule, is critical for the elucidation of its unique roles in cell signaling and many cellular reactions. Up to date, a major challenge is still remaining for fabricating surface-enhanced Raman scattering (SERS) aptamer sensors (aptasensors) suitable for accurate and reliable quantification of ATP. Herein, we develop the ratiometric silicon SERS aptasensor for ATP detection, which is made of uniform silver nanoparticles (Ag NPs)-modified silicon wafer (Ag NPs@Si), followed by the functionalization with double-stranded DNA (dsDNA I). The dsDNA I is formed by the aptamer and its complementary DNA (cDNA), which contains two independent segments (e.g., 5'-Cy3-labeled DNA-C1, 3'-ROX-labeled DNA-C2). In the presence of ATP, ROX-DNA-C2 is dissociated from dsDNA I due to the formation of aptamer/ATP complex, leading to the attenuation of ROX signals, and meanwhile, Cy3 signals remain constant ascribed to the formation of dsDNA II caused by the supplementation of aptamer. As a result, ratiometric signals of the ratio of ROX intensity to Cy3 intensity (IROX/ICy3) can be achieved. Of particular significance, the developed ATP aptasensor features excellent reproducibility [e.g., the relative standard deviation (RSD) is less than ∼4%, comparable or superior to that of previously reported aptasensors], ultrahigh sensitivity [e.g., the detection of limit (LOD) reaches 9.12 pM, lower than that of other reported ATP SERS aptasensors], as well as good recyclability (e.g., ∼9.3% of RSD values of ratiometric signals within three cycles).

Impact of fluorescent silicon nanoparticles on circulating hemolymph and hematopoiesis in an invertebrate model organism.

Silicon nanoparticles (SiNPs) have attractive potential applications in biological and medical fields, and yet their impact on animals is still controversial, and there have been no reports of their effects on hematopoiesis. In this study, the effects of SiNPs on hemocytes and hematopoiesis were investigated by administering SiNPs via a vascular injection into an invertebrate model, the silkworm. Our results show that the ability of SiNPs to enter different types of circulating hemocytes and their impact on those hemocytes differed significantly. Rapid accumulation of SiNPs was observed in granulocytes, oenocytoids, and spherulocytes, which have immune functions in the circulating hemolymph, whereas SiNPs did not easily enter prohemocytes, which can differentiate into granulocytes, oenocytoids, and spherulocytes and replenish them. The SiNPs that entered the hemocytes initiated autophagy and apoptosis via the lysosomal/mitochondrial pathway. High-dose SiNPs weakly stimulated lysosomal activity in hematopoietic organs, but did not lead to a significant increase in reactive oxygen species or severe autophagy or apoptosis in the organ tissues. We suggest that the damage caused by high-dose SiNPs to hematopoiesis is self-healing, because few SiNPs entered the hematopoietic stem cells in the circulating hemolymph, so the damage to the hematopoietic tissues was limited.

YiXin-Shu, a ShengMai-San-based traditional Chinese medicine formula, attenuates myocardial ischemia/reperfusion injury by suppressing mitochondrial mediated apoptosis and upregulating liver-X-receptor α.

Positive evidence from clinical trials has fueled growing acceptance of traditional Chinese medicine (TCM) for the treatment of cardiac diseases; however, little is known about the underlying mechanisms. Here, we investigated the nature and underlying mechanisms of the effects of YiXin-Shu (YXS), an antioxidant-enriched TCM formula, on myocardial ischemia/reperfusion (MI/R) injury. YXS pretreatment significantly reduced infarct size and improved viable myocardium metabolism and cardiac function in hypercholesterolemic mice. Mechanistically, YXS attenuated myocardial apoptosis by inhibiting the mitochondrial mediated apoptosis pathway (as reflected by inhibition of mitochondrial swelling, cytochrome c release and caspase-9 activity, and normalization of Bcl-2 and Bax levels) without altering the death receptor and endoplasmic reticulum-stress death pathways. Moreover, YXS reduced oxidative/nitrative stress (as reflected by decreased superoxide and nitrotyrosine content and normalized pro- and anti-oxidant enzyme levels). Interestingly, YXS upregulated endogenous nuclear receptors including LXRα, PPARα, PPARß and ERα, and in-vivo knockdown of cardiac-specific LXRα significantly blunted the cardio-protective effects of YXS. Collectively, these data show that YXS is effective in mitigating MI/R injury by suppressing mitochondrial mediated apoptosis and oxidative stress and by upregulating LXRα, thereby providing a rationale for future clinical trials and clinical applications.

[Postpartum pelvic floor rehabilitation on prevention of female pelvic floor dysfunction: a multicenter prospective randomized controlled study].

OBJECTIVE: To study the postpartum pelvic floor rehabilitation on the improvement of pelvic floor electrical physiological indexes and the prevention of female pelvic floor dysfunction in China. METHODS: A multicenter prospective randomized controlled study was carried out. From October 2011, postpartum women in five provinces were randomly assigned into treatment group and control group. The women in treatment group received electrical stimulation and biofeedback treatment. The women in control group performed pelvic floor muscle exercise at home. When 6 months and 12 months after delivery, comparing two groups of patients with pelvic floor electrical physiological indexes and pelvic organ prolapse quantitation measurements (POP-Q), to evaluate the effect of postpartum pelvic floor rehabilitation on the prevention of pelvic floor dysfunction. Pelvic floor impact questionnaire short form (PFIQ-7) and pelvic organ prolapse/incontinence sexual questionnaire-12 (PISQ-12) were used to evaluate the influence on quality of life and sexual life. RESULTS: Until June 2013, 324 women were participated, 124 in control group, 200 in treatment group. According to the baseline results, there was statistical significance in the results of pelvic floor electrical physiological indexes between the treatment and control groups in postpartum 6 months and 12 months; the proportion above level III of type I and type II muscle fibers strength in the treatment group, it was from 41.5% (83/200) and 40.5% (81/200) to 76.3% (145/190) and 79.5% (151/190) in postpartum 6 weeks and postpartum 6 months, increased to 80.6% (58/72) and 80.6% (58/72) in postpartum 12 months, improved significantly comparing with the control group (P < 0.01). According to Point Aa, treatment group and control group in the postpartum 6 weeks was (-2.2 ± 0.7) versus (-2.4 ± 0.6) cm, in postpartum 12 months (- 2.5 ± 1.1) versus (- 2.7 ± 0.6) cm, the improvement in treatment group was statistically significant (P < 0.01). And the other points were not significantly different (P > 0.05). There was no significant difference in the questionnaires in quality of life and quality of sexual life (P > 0.05). CONCLUSION: Neuromuscular electrical stimulation and biofeedback therapy in the early postpartum period could obviously improve pelvic floor electrical physiological indexes, and is beneficial to prevent the pelvic floor dysfunction.

Silicon nanostructures for cancer diagnosis and therapy.

The emergence of nanotechnology suggests new and exciting opportunities for early diagnosis and therapy of cancer. During the recent years, silicon-based nanomaterials featuring unique properties have received great attention, showing high promise for myriad biological and biomedical applications. In this review, we will particularly summarize latest representative achievements on the development of silicon nanostructures as a powerful platform for cancer early diagnosis and therapy. First, we introduce the silicon nanomaterial-based biosensors for detecting cancer markers (e.g., proteins, tumor-suppressor genes and telomerase activity, among others) with high sensitivity and selectivity under molecular level. Then, we summarize in vitro and in vivo applications of silicon nanostructures as efficient nanoagents for cancer therapy. Finally, we discuss the future perspective of silicon nanostructures for cancer diagnosis and therapy.

Silicon nanowire-based therapeutic agents for in vivo tumor near-infrared photothermal ablation.

The first example of silicon nanowire (SiNW)-based in vivo tumor phototherapy is presented. Gold nanoparticle (AuNP)-decorated SiNWs are employed as high-performance NIR hyperthermia agents for highly efficacious in vivo tumour ablation. Significantly, the overall survival time of SiNW-treated mice is drastically prolonged, with 100% of mice being alive and tumor-free for over 8 months, which is the longest survival time ever reported for tumor-bearing mice treated with nanomaterial-based NIR hyperthermia agents.

[Comparison of the efficiency of techniques for deconvolving auditory-evoked potentials with high rate stimulation].

In some auditory evoked potential (AEP) examinations, high rate stimulation paradigms deliver more stimuli with the same period of time, which might lead to overlapping responses. At present, several established techniques can be proposed to address such problem, thus the research scope in both scientific and clinical applications is expanded. In this study, the restoring efficiency of evoked responses is investigated using a simulation strategy. We examined the AEPs derived from three paradigms--conventional ensemble averaging, continuous loop averaging deconvolution (CLAD) and maximum length sequence (MLS). Their performances were evaluated by correlation coefficients and Euclidean distances between ideal and the derived responses. We found that MLS can only slightly enhance the performance at the cost of larger stimulus jitter and much more stimulus numbers; while CLAD method with lower jittering even degenerates the quality, suggesting that, in practical use, the recording efficiency will not be significantly improved by simply using high rate stimulation with overlapping responses introduced.

A simulation study assessing the efficiency of deriving evoked responses using high stimulus rate.

This study investigates the effects of stimulus rate on the recording efficiency of evoked-response scenario using a computer generated data simulating auditory evoked potentials (AEPs). We examine AEPs derived from three paradigms: 1) Conventional stimuli for ensemble averaging; 2) continuous loop averaging deconvolution (CLAD); and 3) maximum length sequence (MLS) stimuli, in which deconvolution techniques are incorporated to retrieve the overlapped responses. The performance is evaluated by correlation coefficients between the ideal and the derived responses. The results show that there is no distinct improvement of SNR for high rate stimulation paradigms, suggesting that the techniques of deconvolution in high rate will not provide more efficient recording approach. Further, responses from the CLAD paradigm tend to deteriorate compared to the other two methods due to the lower jittering arrangement of the sequence.