scholarly journals Propagating Wave and Irregular Dynamics: Spatiotemporal Patterns of Cholinergic Theta Oscillations in Neocortex In Vitro

2003 ◽  
Vol 90 (1) ◽  
pp. 333-341 ◽  
Author(s):  
Weili Bao ◽  
Jian-Young Wu
Keyword(s):  
Phase Distribution ◽  
Signal To Noise Ratio ◽  
Human Subjects ◽  
Local Oscillator ◽  
Spatiotemporal Patterns ◽  
Spatiotemporal Pattern ◽  
Large Signal ◽  
Local Oscillators ◽  
Theta Oscillation

Neocortical “theta” oscillation (5–12 Hz) has been observed in animals and human subjects but little is known about how the oscillation is organized in the cortical intrinsic networks. Here we use voltage-sensitive dye and optical imaging to study a carbachol/bicuculline induced theta (∼8 Hz) oscillation in rat neocortical slices. The imaging has large signal-to-noise ratio, allowing us to map the phase distribution over the neocortical tissue during the oscillation. The oscillation was organized as spontaneous epochs and each epoch was composed of a “first spike,” a “regular” period (with relatively stable frequency and amplitude), and an “irregular” period (with variable frequency and amplitude) of oscillations. During each cycle of the regular oscillation, one wave of activation propagated horizontally (parallel to the cortical lamina) across the cortical section at a velocity of ∼50 mm/s. Vertically the activity was synchronized through all cortical layers. This pattern of one propagating wave associated with one oscillation cycle was seen during all the regular cycles. The oscillation frequency varied noticeably at two neighboring horizontal locations (330 μm apart), suggesting that the oscillation is locally organized and each local oscillator is about ≤300 μm wide horizontally. During irregular oscillations, the spatiotemporal patterns were complex and sometimes the vertical synchronization decomposed, suggesting a de-coupling among local oscillators. Our data suggested that neocortical theta oscillation is sustained by multiple local oscillators. The coupling regime among the oscillators may determine the spatiotemporal pattern and switching between propagating waves and irregular patterns.

scholarly journals IL-6 Receptor Blockade Increases Circulating Adiponectin Levels in People with Obesity: An Explanatory Analysis

Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 79
Author(s):  
Stephan Wueest ◽  
Eleonora Seelig ◽  
Katharina Timper ◽  
Mark P. Lyngbaek ◽  
Kristian Karstoft ◽  
...  
Keyword(s):  
Exercise Training ◽  
Human Subjects ◽  
Receptor Blockade ◽  
Model Assessment ◽  
Serum Samples ◽  
Double Blind ◽  
Double Blind Clinical Trial ◽  
Homeostatic Model Assessment ◽  
Obese Human

Human obesity is associated with decreased circulating adiponectin and elevated leptin levels. In vitro experiments and studies in high fat diet (HFD)-fed mice suggest that interleukin-6 (IL-6) may regulate adiponectin and leptin release from white adipose tissue (WAT). Herein, we aimed to investigate whether IL-6 receptor blockade affects the levels of circulating adiponectin and leptin in obese human individuals. To this end, serum samples collected during a multicenter, double-blind clinical trial were analyzed. In the latter study, obese human subjects with or without type 2 diabetes were randomly assigned to recurrent placebo or intravenous tocilizumab (an IL-6 receptor antibody) administration during a 12-week exercise training intervention. Twelve weeks of tocilizumab administration (in combination with exercise training) trend wise enhanced the decrease in circulating leptin levels (−2.7 ± 8.2% in the placebo vs. −20.6 ± 5.6% in tocilizumab, p = 0.08) and significantly enhanced the increase in circulating adiponectin (3.4 ± 3.7% in the placebo vs. 27.0 ± 6.6% in tocilizumab, p = 0.01). In addition, circulating adiponectin levels were negatively correlated with the homeostatic model assessment of insulin resistance (HOMA-IR), indicating that increased adiponectin levels positively affect insulin sensitivity in people with obesity. In conclusion, IL-6 receptor blockade increases circulating adiponectin levels in people with obesity.

Analogy Models for Prediction of Human Toxicity

1990 ◽  
Vol 18 (1_part_1) ◽  
pp. 103-116
Author(s):  
Sven Hellberg ◽  
Lennart Eriksson ◽  
Jörgen Jonsson ◽  
Fredrik Lindgren ◽  
Michael Sjöström ◽  
...  
Keyword(s):  
Human Subjects ◽  
Toxicity Testing ◽  
In Vitro Cytotoxicity ◽  
Alternative Methods ◽  
Laboratory Animals ◽  
In Vitro Tests ◽  
Human Toxicity ◽  
Efficient Data ◽  
Basal Cytotoxicity

Estimating the toxicity to humans of chemicals by testing on human subjects is not considered to be ethically acceptable, and toxicity testing on laboratory animals is also questionable. Therefore, there is a need for alternative methods that will give estimates of various aspects of human toxicity. Batteries of in vitro tests, together with physicochemical and toxicokinetic data, analysed by efficient data analytical methods, may enable analogy models to be constructed that can predict human toxicity. It may be possible to model non-specific toxicity relating to lipophilicity, or basal cytotoxicity, for a series of diverse compounds with large variation in chemical structure and physicochemical properties. However, local models for a series of similar compounds are generally expected to be more accurate, as well as being capable of modelling more-specific interactions. Analogy models for the prediction of human toxicity are discussed and exemplified with physicochemical and cytotoxicity data from the first ten chemicals in the multicenter evaluation of in vitro cytotoxicity (MEIC) project.

SYNCHRONIZATION PHENOMENA IN NETWORKS OF COUPLED RELAXATION ELECTROCHEMICAL OSCILLATIONS

2006 ◽  
Vol 16 (07) ◽  
pp. 1951-1960 ◽  
Author(s):  
ANTONIS KARANTONIS ◽  
MICHAEL PAGITSAS ◽  
YASUYUKI MIYAKITA ◽  
SEIICHIRO NAKABAYASHI
Keyword(s):  
Laser Pulse ◽  
Phase Relation ◽  
Spatiotemporal Patterns ◽  
Spatiotemporal Pattern ◽  
Network Geometry ◽  
Weakly Coupled

Networks of weakly coupled discrete electrochemical oscillators have the ability of synchronizing rapidly in-phase or out-of-phase, depending on the network geometry. It is shown that a network consisting of N relaxation electrochemical oscillators, coupled through inhibitory connections, can have (N - 1)! coexisting out-of-phase states, each state being a permutation of a periodic spiking sequence. The out-of-phase states can be modified by shots of laser pulse perturbations and the phase relation is stored as a coded spatiotemporal pattern. The ability of the network to function as a re-writable memory of (N - 1)! different spatiotemporal patterns is demonstrated experimentally for N = 4.

Clock gene-independent daily regulation of haemoglobin oxidation in red blood cells

2021 ◽  
Author(s):  
Andrew D. Beale ◽  
Priya Crosby ◽  
Utham K. Valekunja ◽  
Rachel S. Edgar ◽  
Johanna E. Chesham ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Human Subjects ◽  
Developmental Regulation ◽  
Physiological Role ◽  
Cell Types ◽  
The Body

AbstractCellular circadian rhythms confer daily temporal organisation upon behaviour and physiology that is fundamental to human health and disease. Rhythms are present in red blood cells (RBCs), the most abundant cell type in the body. Being naturally anucleate, RBC circadian rhythms share key elements of post-translational, but not transcriptional, regulation with other cell types. The physiological function and developmental regulation of RBC circadian rhythms is poorly understood, however, partly due to the small number of appropriate techniques available. Here, we extend the RBC circadian toolkit with a novel biochemical assay for haemoglobin oxidation status, termed “Bloody Blotting”. Our approach relies on a redox-sensitive covalent haem-haemoglobin linkage that forms during cell lysis. Formation of this linkage exhibits daily rhythms in vitro, which are unaffected by mutations that affect the timing of circadian rhythms in nucleated cells. In vivo, haemoglobin oxidation rhythms demonstrate daily variation in the oxygen-carrying and nitrite reductase capacity of the blood, and are seen in human subjects under controlled laboratory conditions as well as in freely-behaving humans. These results extend our molecular understanding of RBC circadian rhythms and suggest they serve an important physiological role in gas transport.

Gravity meter observation of free modes excited by the August 19, 1977 Indonesia earthquake

1979 ◽  
Vol 69 (5) ◽  
pp. 1445-1454
Author(s):  
John A. Linton ◽  
D. E. Smylie ◽  
O. G. Jensen
Keyword(s):  
Signal To Noise Ratio ◽  
Quartz Fiber ◽  
Large Signal ◽  
Signal To Noise ◽  
Definitive Evidence ◽  
Long Period ◽  
Noise Ratio

abstract Free modes with signal-to-noise ratio in the range of 40 to 55 dB were observed in the record taken by a vertical broadband quartz fiber gravimeter system opeating in Montreal following the event of August 19, 1977 in Indonesia. The large signal-to-noise ratio has permitted very stable Q estimates to be made for a number of the fundamental spheroidal modes. The very long-period band shows no definitive evidence of signal other than the expected tidal lines.

scholarly journals A systematic review of the neurobiological aspects of memory in the aging process

2011 ◽  
Vol 5 (4) ◽  
pp. 310-321
Author(s):  
Eduardo Moreira de Oliveira ◽  
Priscilla Tiemi Kissaki ◽  
Tiago Nascimento Ordonez ◽  
Thaís Bento Lima-Silva
Keyword(s):  
Systematic Review ◽  
Aging Process ◽  
Human Subjects ◽  
Basic Research ◽  
Brain Regions ◽  
Morphological Alterations ◽  
Search Terms ◽  
Processing Information ◽  
Normal Human

Abstract A systematic review of the neuroanatomical literature was performed to determine the neuropharmacological aspects most relevant to the study of memory processes. Articles were retrieved using the search terms "biology of memory", "memory and aging", "memory impairment", "elderly and memory," and their equivalents in Portuguese. Of the studies surveyed, five studies dealt with epidemiological and demographic issues, 12 were clinical trials i.e. were based on testing and implementation of instruments in human subjects, 33 studies were basic research involving studies of mice, rats and non-human primates, and biochemical and in vitro trials and finally, 52 studies were literature reviews or book chapters which in our view, fell into this category. Conclusions: The work sought to highlight which neural networks are most involved in processing information, as well as their location within brain regions and the way in which neurotransmitters interact with each other for the formation of these memories. Moreover, it was shown how memory changes during the normal human aging process, both positively and negatively, by analyzing the morphological alterations that occur in the brain of aging individuals.

scholarly journals Effects of Contact Pressure in Reflectance Photoplethysmography in an In Vitro Tissue-Vessel Phantom

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8421
Author(s):  
James M May ◽  
Elisa Mejía-Mejía ◽  
Michelle Nomoni ◽  
Karthik Budidha ◽  
Changmok Choi ◽  
...  
Keyword(s):  
Contact Pressure ◽  
Morphological Analysis ◽  
Signal To Noise Ratio ◽  
In Vitro Study ◽  
Wearable Technologies ◽  
Sensor Device ◽  
Artificial Tissue ◽  
Optimum Sensor ◽  
Consumer Devices

With the continued development and rapid growth of wearable technologies, PPG has become increasingly common in everyday consumer devices such as smartphones and watches. There is, however, minimal knowledge on the effect of the contact pressure exerted by the sensor device on the PPG signal and how it might affect its morphology and the parameters being calculated. This study explores a controlled in vitro study to investigate the effect of continually applied contact pressure on PPG signals (signal-to-noise ratio (SNR) and 17 morphological PPG features) from an artificial tissue-vessel phantom across a range of simulated blood pressure values. This experiment confirmed that for reflectance PPG signal measurements for a given anatomical model, there exists an optimum sensor contact pressure (between 35.1 mmHg and 48.1 mmHg). Statistical analysis shows that temporal morphological features are less affected by contact pressure, lending credit to the hypothesis that for some physiological parameters, such as heart rate and respiration rate, the contact pressure of the sensor is of little significance, whereas the amplitude and geometric features can show significant change, and care must be taken when using morphological analysis for parameters such as SpO2 and assessing autonomic responses.

scholarly journals Rationally Designing Simple Rod-Like Amphiphilic NIR-Emissive AIE Probes for Precise In-Vivo Detection of Aβ Fibrils/Plaques at A Super-Early Stage

2021 ◽  
Author(s):  
Yipu Wang ◽  
Dong Mei ◽  
Xinyi Zhang ◽  
Da-Hui Qu ◽  
Ju Mei ◽  
...  
Keyword(s):  
High Performance ◽  
Ex Vivo ◽  
Early Stage ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
In Vivo Detection ◽  
Different Strains ◽  
Aβ Fibrils

With increase of social aging, Alzheimer's disease (AD) has been one of the serious diseases threatening human health. The occurrence of A<i>β </i>fibrils<i> </i>or plaques is recognized as the hallmark of AD.<i> </i>Currently, optical imaging has stood out to be a promising technique for the imaging of A<i>β</i> fibrils/plaques and the diagnosis of AD. However, restricted by their poor blood-brain barrier (BBB) penetrability, short-wavelength excitation and emission, and aggregation-caused quenching (ACQ) effect, the clinically used gold-standard optical probes such as <a>thioflavin</a> T (ThT) and thioflavin S (ThS), are not effective enough in the early diagnosis of AD <i>in vivo</i>. Herein, we put forward an “all-in-one” design principle and demonstrate its feasibility in developing high-performance fluorescent probes which are specific to A<i>β</i> fibrils/plaques and promising for super-early <i>in</i>-<i>vivo</i> diagnosis of AD. As a proof of concept, a simple rod-like amphiphilic NIR fluorescent AIEgen, i.e., AIE-CNPy-AD, is developed by taking the specificity, BBB penetration ability, deep-tissue penetration capacity, high signal-to-noise ratio (SNR) into consideration. AIE-CNPy-AD is constituted by connecting the electron-donating and accepting moieties through single bonds and tagging with a propanesulfonate tail, giving rise to the NIR fluorescence, aggregation-induced emission (AIE) effect, amphiphilicity, and rod-like structure, which in turn result in high binding-affinity and excellent specificity to A<i>β</i> fibrils/plaques, satisfactory ability to penetrate BBB and deep tissues, ultrahigh SNR and sensitivity, and high-fidelity imaging capability. <i>In-vitro, ex-vivo,</i> and <i>in-vivo</i> <a>identifying of A<i>β</i> fibrils/plaques</a> in different strains of mice indicate that AIE-CNPy-AD holds the universality to the detection of A<i>β</i> fibrils/plaques. It is noteworthy that AIE-CNPy-AD is even able to trace the small and sparsely distributed A<i>β</i> fibrils/plaques in very young AD model mice such as 4-month-old APP/PS1 mice which are reported to be the youngest mice to have A<i>β</i> deposits in brains, suggesting its great potential in diagnosis and intervention of AD at a super-early stage.

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