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1.
Nat Sci Sleep ; 16: 461-471, 2024.
Article in English | MEDLINE | ID: mdl-38737461

ABSTRACT

Aim: Recent data have identified specific symptom and polysomnographic profiles associated with cardiovascular disease (CVD) in patients with obstructive sleep apnoea (OSA). Our aim was to determine whether these profiles were present at diagnosis of OSA in patients with established CVD and in those with high cardiovascular risk. Participants in the Sydney Sleep Biobank (SSB) database, aged 30-74 years, self-reported presence of CVD (coronary artery disease, cerebrovascular disease, or heart failure). In those without established CVD, the Framingham Risk Score (FRS) estimated 10-year absolute CVD risk, categorised as "low" (<6%), "intermediate" (6-20%), or "high" (>20%). Groups were compared on symptom and polysomnographic variables. Results: 629 patients (68% male; mean age 54.3 years, SD 11.6; mean BMI 32.3 kg/m2, SD 8.2) were included. CVD was reported in 12.2%. A further 14.3% had a low risk FRS, 38.8% had an intermediate risk FRS, and 34.7% had a high risk FRS. Groups differed with respect to age, sex and BMI. OSA severity increased with established CVD and increasing FRS. The symptom of waking too early was more prevalent in the higher FRS groups (p=0.004). CVD and FRS groups differed on multiple polysomnographic variables; however, none of these differences remained significant after adjusting for age, sex, and BMI. Conclusion: Higher CVD risk was associated with waking too early in patients with OSA. Polysomnographic variations between groups were explained by demographic differences. Further work is required to explore the influence of OSA phenotypic characteristics on susceptibility to CVD.

2.
Parasitol Int ; : 102901, 2024 May 14.
Article in English | MEDLINE | ID: mdl-38754812

ABSTRACT

Parasitic neglected tropical diseases, such as schistosomiasis and soil-transmitted helminthiasis (STH), remain as significant public health concerns in developing countries such as the Philippines. This study aimed to determine the prevalence and intensity of schistosomiasis and STH among school-age children (SAC) and adults in two co-endemic provinces in Mindanao in southern Philippines as part of monitoring of national control programs. Stool samples were collected, processed using Kato-Katz technique, and examined microscopically for presence of intestinal helminth ova. A total of 776 SAC and 526 adults participated in the study. Low schistosomiasis prevalence was generally observed in SAC (0.8%) and adults (0.4%). Generally low STH prevalence was reported in both SAC (3.9%) and adults (3.4%). Only three SAC had heavy intensity STH, which was not seen in adults. Results indicate a state of good morbidity control, which may be a result of effective implementation of mass drug administration (MDA) strategy for schistosomiasis, STH, and lymphatic filariasis in the last several years. The low prevalence and intensities of infections may also be partly attributed to the low diagnostic sensitivity of Kato-Katz technique in detecting low intensity intestinal helminth infections. While results of this study also indicate similarly low levels of both these infections in previous studies, sustaining high MDA coverage rates and addressing remaining challenges related to intensified case finding and treatment, improvements in safe water, sanitation, and hygiene, veterinary public health, and vector ecology and management will be necessary to interrupt transmission in these areas.

3.
Prosthet Orthot Int ; 2024 May 21.
Article in English | MEDLINE | ID: mdl-38771747

ABSTRACT

Gritti-Stokes amputation (GSA) is a knee disarticulation variant, where the femur is transected at the level of the epicondyle and the patella is fixated to the distal end. GSA results in a long residual limb with little postoperative swelling and less potential for muscular atrophy, so stable limb volume may allow the use of seal-in suction for suspension for preparatory prostheses. The purpose of this case series was to report on the efficacy of seal-in suction preparatory prostheses for 2 adults with traumatic GSA. Between October and December of 2021, 2 participants with unilateral traumatic Gritti-Stokes amputation, who had received seal-in suction suspension for their preparatory prostheses, were recruited. Information was extracted from medical charts regarding prosthetic care and mobility at preparatory and definitive prosthesis evaluation, and participants underwent standardized measurement of their residual limb and prosthesis. Duration of preparatory prosthesis use was >6 months; neither participant reported loss of suspension nor significant complications with socket fit. Participant 1 required socket replacement because of residual limb pain secondary to osteophyte formation, and Participant 2 required component replacement because of weight gain. At definitive prosthesis evaluations, both participants were unlimited community ambulators; both successfully returned to work before provision of their definitive prostheses. Results indicate that seal-in suction suspension may be viable for preparatory prostheses among adults with traumatic GSA, but knee center height discrepancies persist. GSA may yield highly functional outcomes for adults with traumatic amputation. Further research is required to substantiate these findings.

4.
Life Sci Space Res (Amst) ; 41: 191-201, 2024 May.
Article in English | MEDLINE | ID: mdl-38670647

ABSTRACT

The cortical anthraquinone yellow-orange pigment parietin is a secondary lichen substance providing UV-shielding properties that is produced by several lichen species. In our work, the secondary metabolite has been extracted from air-dried thalli of Xanthoria parietina. The aims of this study were to characterize parietin absorbance through UV-VIS spectrophotometry and with IR spectroscopy and to evaluate its photodegradability under UV radiation through in situ reflectance IR spectroscopy to understand to what extent the substance may have a photoprotective role. This allows us to relate parietin photo-degradability to the lichen UV tolerance in its natural terrestrial habitat and in extreme environments relevant for astrobiology such as Mars. Extracted crystals were UV irradiated for 5.59 h under N2 flux. After the UV irradiation, we assessed relevant degradations in the 1614, 1227, 1202, 1160 and 755 cm-1 bands. However, in light of Xanthoria parietina survivability in extreme conditions such as space- and Mars-simulated ones, we highlight parietin UV photo-resistance and its relevance for astrobiology as photo-protective substance and possible bio-hint.


Subject(s)
Emodin/analogs & derivatives , Exobiology , Lichens , Ultraviolet Rays , Lichens/radiation effects , Lichens/chemistry , Photolysis , Spectrophotometry, Infrared
5.
Trop Med Health ; 52(1): 25, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38491552

ABSTRACT

BACKGROUND: Dengue has become a major health issue in tropical regions as the numbers of reported cases and estimated infections continuously increase. In the Philippines, many challenges remain in preventing and controlling the disease amidst all the mitigation efforts of the government. This study sought to measure the health literacy of Filipino teachers and determine the associations among teachers' knowledge, attitudes, and selected practices (KAP) against dengue. METHODS: Elementary and secondary school teachers from the consistently declared dengue hotspots in the City of San Fernando, Pampanga, Philippines, from the years 2017 to 2019 were selected as target participants in this cross-sectional study. A self-administered online survey tool was used in this study for both screening of participants and the KAP survey proper. STATA, descriptive statistics, and multiple logistic regression were used for the data analysis. Odds Ratios (ORs) and 95% confidence intervals (CIs) were reported. RESULTS: The study comprised 604 participants whose mean age was 38.4 years. Television was determined as the top media source of information, and various health staff were the most trusted and common source of information. Good knowledge on dengue treatment (OR = 1.81; 95% CI 1.18-2.78) and dengue prevention (OR = 1.85; 95% CI 1.26-2.71) were positively associated with having good practices on protection against mosquito bites. Good knowledge on dengue signs and symptoms (OR = 1.56; 95% CI 1.02-2.37) and dengue prevention (OR = 2.38; 95% CI 1.59-3.58) were positively associated with having good practices on preventing breeding sites. Those with positive perceived susceptibility to dengue had lower odds of having good practices on protection against mosquito bites (OR = 0.64; 95% CI 0.41-0.99) and of having good practices on preventing breeding sites (OR = 0.46; 95% CI 0.26-0.81). CONCLUSION: Even with the existing dengue policies, programs, and strategies, and the high disease literacy rate of Filipinos, dengue remains a struggle with an increasing case rate. Therefore, specific concepts should be emphasized, and interventions should be fine-tuned to better reach and influence the target population to attain a dengue-free Philippines.

6.
Geriatr Nurs ; 56: 218-224, 2024.
Article in English | MEDLINE | ID: mdl-38367544

ABSTRACT

OBJECTIVE: The aim of this study was to evaluate the prevalence of, and explore factors related to, prescription of potentially inappropriate medications (PIMs) among older adults with lower-limb loss (LLL). METHODS: This was a secondary analysis of a cross-sectional dataset collected through an interdisciplinary limb loss clinic between September 2013 and November 2022. Self-report medication lists were reviewed during in-clinic face-to-face interviews and compared to the American Geriatrics Society Beers Criteria corresponding to the patient's evaluation year. RESULTS: Of 82 participants (72.9 ± 6.6 years-old; 78.0 % male), n = 41 (50.0 %) reported using one or more PIM. PIM prescription was significantly associated with presence of phantom limb pain, history of upper gastrointestinal issues, and a greater number of medications. DISCUSSION: Polypharmacy and PIM use are common among older adults with LLL. Greater attention should be paid to medications post-amputation, especially pain management medications, to minimize potential adverse side-effects.


Subject(s)
Geriatrics , Potentially Inappropriate Medication List , Humans , Male , Aged , Female , Inappropriate Prescribing , Cross-Sectional Studies , Polypharmacy
7.
Regen Biomater ; 11: rbad115, 2024.
Article in English | MEDLINE | ID: mdl-38313824

ABSTRACT

Metal-organic frameworks (MOFs) have a high specific surface area, adjustable pores and can be used to obtain functional porous materials with diverse and well-ordered structures through coordination and self-assembly, which has intrigued wide interest in a broad range of disciplines. In the arena of biomedical engineering, the functionalized modification of MOFs has produced drug carriers with excellent dispersion and functionalities such as target delivery and response release, with promising applications in bio-detection, disease therapy, tissue healing, and other areas. This review summarizes the present state of research on the functionalization of MOFs by physical binding or chemical cross-linking of small molecules, polymers, biomacromolecules, and hydrogels and evaluates the role and approach of MOFs functionalization in boosting the reactivity of materials. On this basis, research on the application of functionalized MOFs composites in biomedical engineering fields such as drug delivery, tissue repair, disease treatment, bio-detection and imaging is surveyed, and the development trend and application prospects of functionalized MOFs as an important new class of biomedical materials in the biomedical field are anticipated, which may provide some inspiration and reference for further development of MOF for bio-medical applications.

8.
Biotechnol J ; 19(2): e2300446, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38403442

ABSTRACT

Accumulation of the ribonucleoside, adenosine (ADO), triggers a cAMP response element binding protein (CREB)-mediated signaling pathway to suppress the function of immune cells in tumors. Here, we describe a collection of CREB-activated promoters that allow for strong and tunable ADO-induced gene expression in human cells. By optimizing number of CREB transcription factor binding sites and altering the core promoter region of CREB-based hybrid promoters, we created synthetic constructs that drive gene expression to higher levels than strong, endogenous mammalian promoters in the presence of ADO. These synthetic promoters are induced up to 47-fold by ADO, with minimal expression in their "off" state. We further determine that our CREB-based promoters are activated by other compounds that act as signaling analogs, and that combinatorial addition of ADO and these compounds has a synergistic impact on gene expression. Surprisingly, we also detail how background ADO degradation caused by the common cell culture media additive, fetal bovine serum (FBS), confounds experiments designed to determine ADO dose-responsiveness. We show that only after long-term heat deactivation of FBS can our synthetic promoters enable gene expression induction at physiologically relevant levels of ADO. Finally, we demonstrate that the strength of a CREB-based promoter is enhanced by incorporating other transcription factor binding sites.


Subject(s)
Adenosine , Cyclic AMP Response Element-Binding Protein , Animals , Humans , Cyclic AMP Response Element-Binding Protein/genetics , Cyclic AMP Response Element-Binding Protein/metabolism , Adenosine/genetics , Cyclic AMP/metabolism , Promoter Regions, Genetic/genetics , Gene Expression , Transcription, Genetic , Mammals/genetics
9.
10.
Health Promot J Austr ; 35(1): 225-234, 2024 Jan.
Article in English | MEDLINE | ID: mdl-36961054

ABSTRACT

ISSUE ADDRESSED: Aboriginal and Torres Strait Islander child ear health is complex and multiple. We examined relationships between parent-reported sociodemographic, child health, health service access factors and ear symptoms among Aboriginal and Torres Strait Islander children aged 3 to 7 years. METHODS: The Longitudinal Study of Indigenous Children is a large child cohort study with annual parent-reported data collection. Generalised linear mixed model analyses examined Wave 1 (1309 children 0-5 years; 2008) predictors of being free of parent-reported ear symptoms in both Waves 2 and 3. RESULTS: A total of 1030 (78.7%) had no reported ear symptoms in either Wave 2 or 3. In the fully adjusted model, children who had been hospitalised in the past year (aOR = 2.16; 95% CI 1.19-3.93) and those with no ear symptoms (aOR = 2.94; 95% CI, 1.59-5.46) at Wave 1 had higher odds of no ear symptoms in both the subsequent waves. There were also relationships between parent main source of income-government pension or allowance as well as parents who reported no history of their own ear symptoms and higher odds of no ear symptoms in Waves 2 and 3 after partial adjustment for sociodemographic factors. CONCLUSION: These findings suggest relationships between different sociodemographic and health factors and parent-reported ear symptoms among Aboriginal and Torres Strait Islander children that warrant further investigation. So what? Children with parent-reported ear symptoms during the early years need holistic support to prevent future ear symptoms that impact health, social and educational life trajectories.


Subject(s)
Australian Aboriginal and Torres Strait Islander Peoples , Ear Diseases , Health Services, Indigenous , Child , Humans , Cohort Studies , Data Collection , Longitudinal Studies , Parents , Ear Diseases/epidemiology
12.
J Public Health Manag Pract ; 30(2): 285-294, 2024.
Article in English | MEDLINE | ID: mdl-38151718

ABSTRACT

OBJECTIVE: To assess sudden unexpected infant death (SUID) investigations for structural inequities by race/ethnicity and geography. METHODS: The SUID Case Registry compiles data on death investigations. We analyzed cases from 2015 to 2018 (N = 3847) to examine likelihood of an incomplete death investigation, defined as missing autopsy, missing scene investigation, or missing detailed information about where and how the body was found. We also analyzed which specific components of death investigations led to the greatest number of incomplete investigations. RESULTS: Twenty-four percent of SUIDs had incomplete death investigations. Death scenes in rural places had 1.51 times the odds of incomplete death investigations (95% confidence interval [CI], 1.19-1.92) compared with urban areas. Scene investigations led by law enforcement were more likely to result in incomplete death investigations (odds ratio [OR] = 1.49; 95% CI, 1.18-1.88) than those led by medical examiners. American Indian/Alaska Native SUIDs were more likely than other racial groups to have an incomplete investigation (OR = 1.49; 95% CI, 0.92-2.42), more likely to occur in rural places ( P = .055), and more likely to be investigated by law enforcement ( P < .001). If doll reenactments had been performed, 358 additional cases would have had complete investigations, and if SUID investigation forms had been performed, 243 additional cases would have had complete investigations. American Indian/Alaska Native SUIDs were also more likely to be missing specific components of death investigations. CONCLUSION: To produce equitable public health surveillance data used in prevention efforts, it is crucial to improve SUID investigations, especially in rural areas and among American Indian/Alaska Native babies.


Subject(s)
Sudden Infant Death , Infant , Humans , Animals , Swine , Cause of Death , Sudden Infant Death/epidemiology , Sudden Infant Death/prevention & control , Registries , Racial Groups , Coroners and Medical Examiners
13.
Chaos ; 33(12)2023 Dec 01.
Article in English | MEDLINE | ID: mdl-38127291

ABSTRACT

We have observed the transient dynamics in nematic electroconvection during a sudden change in the driving voltage. The steady state dynamics of nematic electroconvection during a constant driving voltage are well characterized examples of spatiotemporal chaos, and thus are useful for the study of chaotic transients. For a set of starting conditions, we were able to show that the system can enter a long-lived transient state with a larger power dissipation rate. This transient state decays through the skew varicose instabilities into steady state defect turbulence. We observed the onset of both Eckhaus and skew varicose instabilities, interpret this transition in the framework of dynamical crisis, and quantify the transition through the evolution of the information entropy in the images as well as the power dissipated by the sample. We identify this long-lived but transient state as originating from the structure of the convective rolls in the initial state and hypothesize that the exploitation of transient states such as these may occur in natural systems and could be leveraged for industrial processing.

14.
Planta ; 259(1): 25, 2023 Dec 18.
Article in English | MEDLINE | ID: mdl-38108922

ABSTRACT

MAIN CONCLUSION: Xanthoria parietina survivability in Mars-like conditions was supported by water-lysis efficiency recovery and antioxidant content balancing with ROS production after 30 days of exposure. Xanthoria parietina (L.) Th. Fr. is a widespread lichen showing tolerance against air pollutants and UV-radiation. It has been tested under space-like and Mars-like conditions resulting in high recovery performances. Hereby, we aim to assess the mechanisms at the basis of the thalli resilience against multiple space stress factors. Living thalli of X. parietina were exposed to simulated Martian atmospheric conditions (Dark Mars) and UV radiation (Full Mars). Then, we monitored as vitality indicator the photosynthetic efficiency, assessed by in vivo chlorophyll emission fluorescence measurements (FM; FV/F0). The physiological defense was evaluated by analyzing the thalli antioxidant capacity. The drop of FM and FV/F0 immediately after the exposure indicated a reduction of photosynthesis. After 24 h from exposure, photosynthetic efficiency began to recover suggesting the occurrence of protective mechanisms. Antioxidant concentrations were higher during the exposure, only decreasing after 30 days. The recovery of photosynthetic efficiency in both treatments suggested a strong resilience by the photosynthetic apparatus against combined space stress factors, likely due to the boosted antioxidants at the beginning and their depletion at the end of the exposure. The overall results indicated that the production of antioxidants, along with the occurrence of photoprotection mechanisms, guarantee X. parietina survivability in Mars-like environment.


Subject(s)
Mars , Resilience, Psychological , Antioxidants , Extraterrestrial Environment , Oxidative Stress , Photosynthesis
15.
Adv Eng Mater ; 25(17)2023 Sep.
Article in English | MEDLINE | ID: mdl-37982016

ABSTRACT

Herein, fullerenol (Ful), a highly water-soluble derivative of C60 fullerene with demonstrated antioxidant activity, is incorporated into calcium phosphate cements (CPCs) to enhance their osteogenic ability. CPCs with added carboxymethyl cellulose/gelatin (CMC/Gel) are doped with biocompatible Ful particles at concentrations of 0.02, 0.04, and 0.1 wt v%-1 and evaluated for Ful-mediated mechanical performance, antioxidant activity, and in vitro cellular osteogenesis. CMC/gel cements with the highest Ful concentration decrease setting times due to increased hydrogen bonding from Ful's hydroxyl groups. In vitro studies of reactive oxygen species (ROS) scavenging with CMC/gel cements demonstrate potent antioxidant activity with Ful incorporation and cement scavenging capacity is highest for 0.02 and 0.04 wt v%-1 Ful. In vitro cytotoxicity studies reveal that 0.02 and 0.04 wt v%-1 Ful cements also protect cellular viability. Finally, increase of alkaline phosphatase (ALP) activity and expression of runt-related transcription factor 2 (Runx2) in MC3T3-E1 pre-osteoblast cells treated with low-dose Ful cements demonstrate Ful-mediated osteogenic differentiation. These results strongly indicate that the osteogenic abilities of Ful-loaded cements are correlated with their antioxidant activity levels. Overall, this study demonstrates exciting potential of Fullerenol as an antioxidant and proosteogenic additive for improving the performance of calcium phosphate cements in bone reconstruction procedures.

16.
Proc Natl Acad Sci U S A ; 120(45): e2308867120, 2023 Nov 07.
Article in English | MEDLINE | ID: mdl-37903248

ABSTRACT

Recent research concludes that professional American football players (hereafter, "football players") live longer than American men in general, despite experiencing higher rates of chronic traumatic encephalopathy (CTE) and cardiovascular disease (CVD). This suggests that the longevity-enhancing benefits of playing football (e.g., physical fitness, money) outweigh the costs associated with CTE, CVD, and other longevity detriments of playing football. However, these surprising results may be the consequence of flawed research design. To investigate, we conducted two analyses. In analysis 1, we compared a) all professional American football players whose first season was 1986 or between 1988 and 1995 to b) a random sample of same-age American men observed as part of the National Health Interview Surveys in those same years selected on good health, at least 3 y of college, and not being poor. The exposure consists of playing one or more games of professional football; the outcome is risk of death within 25 y. In analysis 2, we use data on 1,365 men drafted to play in the (American) National Football League in the 1950s-906 of whom ultimately played professional football, and 459 of whom never played a game in any professional league. We estimate the association between playing football and survival through early 2023. In both analyses, we investigate differences between linemen and other position players. In contrast to most prior research, in both analyses, we find that linemen died earlier than otherwise similar men; men who played other positions died no earlier (or later).


Subject(s)
Cardiovascular Diseases , Chronic Traumatic Encephalopathy , Football , Male , Humans , United States/epidemiology , Longevity , Surveys and Questionnaires
17.
Inquiry ; 60: 469580231205083, 2023.
Article in English | MEDLINE | ID: mdl-37837278

ABSTRACT

Peripheral neuropathy (PN) and peripheral arterial disease (PAD) are life-limiting comorbidities among adults with lower-limb loss that may not be adequately addressed in current care models. The objective of this study was to evaluate underreporting of PN and PAD among adults with lower-limb loss. We conducted a secondary analysis of a cross-sectional dataset of community-dwelling adults with unilateral lower-limb loss seen in an outpatient Limb Loss Clinic (n = 196; mean age = 56.7 ± 14.4 years; 73.5% male). Individuals participated in standardized clinical examinations including Semmes-Weinstein monofilament testing to assess for PN and pedal pulse palpation to assess for PAD. Bivariate regression was performed to identify key variables for subsequent stepwise logistic regression to discern risk factors. Clinical examination results indicated 16.8% (n = 33) of participants had suspected PN alone, 15.8% (n = 31) had suspected PAD alone, and 23.0% (n = 45) had suspected PN and PAD. More than half of participants with clinical examination findings of PN or PAD failed to self-report the condition (57.7% and 86.8%, respectively). Among adults with lower-limb loss with suspected PN, participants with dysvascular amputations were at lower risk of underreporting (odds ratio [OR] = 0.2, 95% CI: 0.1-0.6). For those with suspected PAD, those who reported more medication prescriptions were at lower risk of underreporting (OR = 0.8, 95% CI: 0.7-1.0). Adults with lower-limb loss underreport PN and PAD per a medical history checklist, which may indicate underdiagnosis or lack of patient awareness. Routine assessment is highly recommended in this population and may be especially critical among individuals with non-dysvascular etiology.


Subject(s)
Peripheral Arterial Disease , Humans , Male , Adult , Middle Aged , Aged , Female , Cross-Sectional Studies , Risk Factors , Comorbidity , Peripheral Arterial Disease/epidemiology , Peripheral Arterial Disease/diagnosis , Peripheral Arterial Disease/surgery , Amputation, Surgical
19.
JMIR Dermatol ; 6: e44405, 2023 Jun 20.
Article in English | MEDLINE | ID: mdl-37632941

ABSTRACT

BACKGROUND: Wide-ranging patient recruitment not restricted to the location of the investigator will provide a better representation of the patient population in clinical studies. OBJECTIVE: Our goal was to assess the feasibility of a broad web-based recruitment strategy in an 8-week observational study of 500 study participants with psoriasis and healthy controls from locations remote from the investigator and to assess the cost associated with each participant. METHODS: A decentralized team in Denmark recruited patients with psoriasis and healthy controls using Google and Facebook advertisements and posts to Facebook groups. All individuals were screened via the internet, and patients diagnosed with psoriasis were included. Questionnaires regarding itch and sleep were completed by both groups at inclusion, week 4, and week 8. RESULTS: During a 2-week recruitment period, 12,887 unique advertisement views were registered, and 839 participants were enrolled, of which 507 completed the study (220 with psoriasis and 287 healthy controls) with a retention rate of 60.4%. Participants were recruited from 11 different countries on 4 separate continents, mainly from the United States, Canada, and the United Kingdom. The recruitment rate was 59.9 participants per day, and the conversion rate was 57.2%. Recruitment costs were US $13 per enrolled participant and US $22 per participant completing the study. CONCLUSIONS: It is feasible and rapid to recruit a large number of participants from locations different from the investigator and to retain patients in an observational study with no visits to a clinical site at low costs.

20.
Biosens Bioelectron ; 239: 115591, 2023 Nov 01.
Article in English | MEDLINE | ID: mdl-37634421

ABSTRACT

Bottom-up neuroscience utilizes small, engineered biological neural networks to study neuronal activity in systems of reduced complexity. We present a platform that establishes up to six independent networks formed by primary rat neurons on planar complementary metal-oxide-semiconductor (CMOS) microelectrode arrays (MEAs). We introduce an approach that allows repetitive stimulation and recording of network activity at any of the over 700 electrodes underlying a network. We demonstrate that the continuous application of a repetitive super-threshold stimulus yields a reproducible network answer within a 15 ms post-stimulus window. This response can be tracked with high spatiotemporal resolution across the whole extent of the network. Moreover, we show that the location of the stimulation plays a significant role in the networks' early response to the stimulus. By applying a stimulation pattern to all network-underlying electrodes in sequence, the sensitivity of the whole network to the stimulus can be visualized. We demonstrate that microchannels reduce the voltage stimulation threshold and induce the strongest network response. By varying the stimulation amplitude and frequency we reveal discrete network transition points. Finally, we introduce vector fields to follow stimulation-induced spike propagation pathways within the network. Overall we show that our defined neural networks on CMOS MEAs enable us to elicit highly reproducible activity patterns that can be precisely modulated by stimulation amplitude, stimulation frequency and the site of stimulation.


Subject(s)
Biosensing Techniques , Animals , Rats , Microelectrodes , Neural Networks, Computer , Neurons , Oxides
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