scholarly journals Review: Chronopharmacology; A Biological Rhythm

2021 ◽  
Vol 23 (12) ◽  
pp. 60-82
Author(s):  
Pooja P. Dahale ◽  
◽  
Mr. Vijay R. Chakote ◽  
Siddesh V Rokade ◽  
Shrikant C. Bhosale ◽  
...  
Keyword(s):  
Biological Rhythms ◽  
Temporal Variations ◽  
External Factors ◽  
Temporal Organization ◽  
Time Dependent ◽  
Peak Time ◽  
Toxic Substances ◽  
Biological Clocks ◽  
Scientific Domain ◽  
Physiological Variables

Chronopharmacology is the study of how the effects of drugs vary with biological timing and endogenous periodicities. The goal is to improve our understanding of periodic and thus predictable (e.g. circadian) changes in both desired effects (chronoeffectiveness) and tolerance (chronotolerance) of medications. Dosing time-dependent changes also include quantification of parameters characterizing endogenous circadian rhythms (CR), in terms of pharmacologic effects, e.g. the 24-h adjusted mean (M), the period , the amplitude (A, the peak-to-trough difference), and the acrophase , the peak time location in the 24-h scale). Chronopharmacology became recognized as a scientific domain of investigation only in the early 1970s. For conventionally trained pharmacologists, it was not clear that predictable temporal variations of effects and disposition of agents (e.g. medications, hormones, and toxic substances) are governed by endogenous biological rhythms rather than by changes of external factors. On the 24-h scale (as well as on the yearly scale) there are peaks and troughs of physiological variables that are not randomly distributed; their respective locations correspond to a temporal organization controlled by a set of pacemakers (so-called biological clocks) became recognized as a scientific domain of investigation only in the early 1970s.

scholarly journals Chronobiology and the design of marine biology experiments

2018 ◽  
Vol 76 (1) ◽  
pp. 60-65 ◽  
Author(s):  
Audrey M Mat
Keyword(s):  
Marine Biology ◽  
Clock Genes ◽  
Biological Rhythms ◽  
Marine Species ◽  
Temporal Organization ◽  
Biological Clocks ◽  
Solar Cycles ◽  
Dark Cycle ◽  
Marine Habitats ◽  
Selection Of

AbstractMarine habitats are shaped by several geophysical cycles ranging from a few hours (tidal and solar cycles) to a year (seasons). These cycles have favoured the selection of endogenous biological clocks. Such a clock is a molecular time-keeping mechanism that consists of a set of core clock genes whose expression oscillates. The clocks produce biological rhythms and influence virtually all metabolic, physiological, and behavioural functions in organisms. This work highlights the importance to take chronobiology into account in experimental marine biology to avoid faulty results, misinterpretation of results, and/or to strengthen observations and conclusion. A literature survey, based on 150 articles, was conducted and showed that, despite the pervasive imprint of biological rhythms in marine species, environmental cycles such as the 24 h-light/dark cycle and the seasonality are rarely considered in experimental designs. This work emphasizes that better integrating the temporal organization and regulation of marine species within the marine biology community is essential for obtaining representative results.

scholarly journals Concepts in human biological rhythms

2003 ◽  
Vol 5 (4) ◽  
pp. 327-342 ◽  
Keyword(s):  
Experimental Data ◽  
Genetic Model ◽  
Clinical Symptoms ◽  
Night Shift ◽  
Biological Rhythms ◽  
Temporal Organization ◽  
Biological Clocks ◽  
Shift Workers ◽  
Left Hand ◽  
The Right

Biological rhythms and their temporal organization are adaptive phenomena to periodic changes in environmental factors linked to the earth's rotation on its axis and around the sun. Experimental data from the plant and animal kingdoms have led to many models and concepts related to biological clocks that help describe and understand the mechanisms of these changes. Many of the prevailing concepts apply to all organisms, but most of the experimental data are insufficient to explain the dynamics of human biological clocks. This review presents phenomena thai are mainly characteristic ofand unique to - human chronobiology, and which cannot be fully explained by concepts and models drawn from laboratory experiments. We deal with the functional advantages of the human temporal organization and the problem of desynchronization, with special reference to the period (τ) of the circadian rhythm and its interindividual and intraindividual variability. We describe the differences between right- and left-hand rhythms suggesting the existence of different biological clocks in the right and left cortices, Desynchronization of rhythms is rather frequent (one example is night shift workers). In some individuals, desynchronization causes no clinical symptoms and we propose the concept of "allochronism" to designate a variant of the human temporal organization with no pathological implications. We restrict the term "dyschronism" to changes or alterations in temporal organization associated with a set of symptoms similar to those observed in subjects intolerant to shift work, eg, persisting fatigue and mood and sleep alterations. Many diseases involve chronic deprivation of sleep at night and constitute conditions mimicking thai of night shift workers who are intolerant to desynchronization. We also present a genetic model (the dian-circadian model) to explain interindividual differences in the period of biological rhythms in certain conditions.

scholarly journals Unraveling the time-dependent relevance of input model uncertainties for a lumped hydrologic model of a pre-alpine karst system

2021 ◽  
Author(s):  
Daniel Bittner ◽  
Beatrice Richieri ◽  
Gabriele Chiogna
Keyword(s):  
Groundwater Recharge ◽  
Temporal Variations ◽  
Hydrologic Model ◽  
Time Dependent ◽  
Model Parameters ◽  
Lumped Parameter ◽  
Hydrodynamic Processes ◽  
Input Model ◽  
Karst Model ◽  
Input Uncertainties

AbstractUncertainties in hydrologic model outputs can arise for many reasons such as structural, parametric and input uncertainty. Identification of the sources of uncertainties and the quantification of their impacts on model results are important to appropriately reproduce hydrodynamic processes in karst aquifers and to support decision-making. The present study investigates the time-dependent relevance of model input uncertainties, defined as the conceptual uncertainties affecting the representation and parameterization of processes relevant for groundwater recharge, i.e. interception, evapotranspiration and snow dynamic, on the lumped karst model LuKARS. A total of nine different models are applied, three to compute interception (DVWK, Gash and Liu), three to compute evapotranspiration (Thornthwaite, Hamon and Oudin) and three to compute snow processes (Martinec, Girons Lopez and Magnusson). All the input model combinations are tested for the case study of the Kerschbaum spring in Austria. The model parameters are kept constant for all combinations. While parametric uncertainties computed for the same model in previous studies do not show pronounced temporal variations, the results of the present work show that input uncertainties are seasonally varying. Moreover, the input uncertainties of evapotranspiration and snowmelt are higher than the interception uncertainties. The results show that the importance of a specific process for groundwater recharge can be estimated from the respective input uncertainties. These findings have practical implications as they can guide researchers to obtain relevant field data to improve the representation of different processes in lumped parameter models and to support model calibration.

scholarly journals Characteristics of Diurnal Rainfall over Peatland Area of South Sumatra, Indonesia

2020 ◽  
Vol 5 (4) ◽  
pp. 136
Author(s):  
Puad Maulana Mandailing ◽  
Wijaya Mardiansyah ◽  
Muhammad Irfan ◽  
Arsali Arsali ◽  
Iskhaq Iskandar
Keyword(s):  
Seasonal Variation ◽  
Early Morning ◽  
Temporal Variations ◽  
In Situ Observation ◽  
Peak Time ◽  
The South ◽  
Night Time ◽  
Late Night ◽  
Diurnal Rainfall

The peak time of rainfall occurrence over an area has certain characteristics in which the difference in time and intensity of rainfall varies depending on its location and distance from the sea. This variation can be determined based on the phase and amplitude obtained using harmonic analysis. In this study, combined data from in-situ observation, satellite remote sensing and reanalysis were used to analyze spatial and temporal variations of peak rainfall events over peatland area of the South Sumatra Province. The results show that most of the South Sumatra Province has a diurnal peak of rainfall during afternoon ranging from 16.00 to 19.00 Western Indonesian Time. In addition, the results also indicate that the analysis on the in situ data revealed seasonal variation both in amplitude and time of maximum diurnal rainfall, while the reanalysis data only indicated a weak seasonal variation on the amplitude of the diurnal rainfall. Furthermore, spatial analysis shows that the time of maximum diurnal rainfall has spatial variation. Over the ocean, the time of maximum diurnal rainfall occurs during night time/early morning. Over the lowland or coastal area, the time of maximum diurnal rainfall occurs during afternoon, while over the high altitude (mountain) it occurs during late night.

scholarly journals Genetic variation and phenotypic plasticity in circadian rhythms in an armed beetle, Gnatocerus cornutus (Tenebrionidae)

2020 ◽  
Vol 130 (1) ◽  
pp. 34-40 ◽  
Author(s):  
Kentarou Matsumura ◽  
Masato S Abe ◽  
Manmohan D Sharma ◽  
David J Hosken ◽  
Taishi Yoshii ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Phenotypic Plasticity ◽  
Circadian Rhythms ◽  
Temperature Effects ◽  
Temperature Compensation ◽  
Biological Rhythms ◽  
Total Activity ◽  
Biological Clocks ◽  
Isofemale Lines ◽  
Free Running

Abstract Circadian rhythms, their free-running periods and the power of the rhythms are often used as indicators of biological clocks, and there is evidence that the free-running periods of circadian rhythms are not affected by environmental factors, such as temperature. However, there are few studies of environmental effects on the power of the rhythms, and it is not clear whether temperature compensation is universal. Additionally, genetic variation and phenotypic plasticity in biological clocks are important for understanding the evolution of biological rhythms, but genetic and plastic effects are rarely investigated. Here, we used 18 isofemale lines (genotypes) of Gnatocerus cornutus to assess rhythms of locomotor activity, while also testing for temperature effects. We found that total activity and the power of the circadian rhythm were affected by interactions between sex and genotype or between sex, genotype and temperature. The males tended to be more active and showed greater increases in activity, but this effect varied across both genotypes and temperatures. The period of activity varied only by genotype and was thus independent of temperature. The complicated genotype–sex–environment interactions we recorded stress the importance of investigating circadian activity in more integrated ways.

Headache and Mood: A Time-Series Analysis of Self-Ratings

Cephalalgia ◽  
1984 ◽  
Vol 4 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Jan Dalkvist ◽  
Karl Ekbom ◽  
Elisabet Waldenlind
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Muscle Contraction ◽  
Time Lag ◽  
Biological Rhythms ◽  
Time Dependent ◽  
Time Intervals ◽  
Independent Variables ◽  
Significant Time ◽  
Dependent Relation

Self-ratings with respect to headache and five mood dimensions were obtained twice daily from five patients suffering from migraine and six patients suffering from muscle-contraction headache during a mean period of 47.9 days (range: 38–61). The data were analysed by multiple regression, with the rated headache as dependent variable. Different time intervals between measurement of the independent variables and measurement of the dependent variable were used. A significant time-dependent relation was found between the migraine ratings and the alertness ratings. Significant time-dependent relations were also found between rated muscle-contraction headache and rated anger and alertness, respectively, but the trends were not very pronounced. In the case of no time lag, rated muscle-contraction headache tended to be negatively related to rated alertness, happiness and concentration. Significant periodic trends were found for both the migraine and the muscle-contraction headache. The major findings are discussed in terms of stress and biological rhythms.

scholarly journals Roles of G1 cyclins in the temporal organization of yeast cell cycle - a transcriptome-wide analysis

2018 ◽  
Author(s):  
Lotte Teufel ◽  
Katja Tummler ◽  
Max Flöttmann ◽  
Andreas Herrmann ◽  
Naama Barkai ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Expression Profiles ◽  
Temporal Organization ◽  
Fine Tuning ◽  
Peak Time ◽  
Time Resolved ◽  
G1 Cyclins ◽  
Measured Time ◽  
Cell Cycle Phases

AbstractOscillating gene expression is crucial for correct timing and progression through cell cycle. In Saccharomyces cerevisiae, G1 cyclins Cln1-3 are essential drivers of the cell cycle and have an important role for temporal fine-tuning. We measured time-resolved transcriptome-wide gene expression for wild type and cyclin single and double knockouts over cell cycle with and without osmotic stress. Clustering of expression profiles, peak-time detection of oscillating genes, integration with transcription factor network dynamics, and assignment to cell cycle phases allowed us to quantify the effect of genetic or stress perturbations on the duration of cell cycle phases. Cln1 and Cln2 showed functional differences, especially affecting later phases. Deletion of Cln3 led to a delay of START followed by normal progression through later phases. Our data and network analysis suggest mutual effects of cyclins with the transcriptional regulators SBF and MBF.

scholarly journals Effects of insemination and blood-feeding on locomotor activity of wild-derived females of the malaria mosquito Anopheles coluzzii

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Amadou S. Traoré ◽  
Angélique Porciani ◽  
Nicolas Moiroux ◽  
Roch K. Dabiré ◽  
Frédéric Simard ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Phenotypic Variability ◽  
Natural Populations ◽  
Malaria Vectors ◽  
Anopheles Coluzzii ◽  
Biological Clocks ◽  
Residual Transmission ◽  
Sustained Activity ◽  
Physiological Variables ◽  
Circadian Control

Abstract Background Behavioural shifts in the canonical location and timing of biting have been reported in natural populations of anopheline malaria vectors following the implementation of insecticide-based indoor vector control interventions. These modifications increase the likelihood of human-vector contact and allow mosquitoes to avoid insecticides, both conditions being favourable to residual transmission of the malarial parasites. The biting behaviour of mosquitoes follows rhythms that are under the control of biological clocks and environmental conditions, modulated by physiological states. In this work we explore modifications of spontaneous locomotor activity expressed by mosquitoes in different physiological states to highlight phenotypic variability associated to circadian control that may contribute to explain residual transmission in the field. Methods The F10 generation progeny of field-collected Anopheles coluzzii from southwestern Burkina Faso was tested using an automated recording apparatus (Locomotor Activity Monitor, TriKinetics Inc.) under LD 12:12 or DD light regimens in laboratory-controlled conditions. Activity recordings of each test were carried out for a week with 6-day-old females belonging to four experimental treatments, representing factorial combinations of two physiological variables: insemination status (virgin vs inseminated) and gonotrophic status (glucose fed vs blood fed). Chronobiological features of rhythmicity in locomotor activity were explored using periodograms, diversity indices, and generalized linear mixed modelling. Results The average strength of activity, onset of activity, and acrophase were modulated by both nutritional and insemination status as well as by the light regimen. Inseminated females showed a significant excess of arrhythmic activity under DD. When rhythmicity was observed in DD, females displayed sustained activity also during the subjective day. Conclusions Insemination and gonotrophic status influence the underlying light and circadian control of chronobiological features of locomotor activity. Overrepresentation of arrhythmic chronotypes as well as the sustained activity of inseminated females during the subjective day under DD conditions suggests potential activity of natural populations of A. coluzzii during daytime under dim conditions, with implications for residual transmission of malarial parasites. Graphical abstract

Cardiovascular chronobiology: implications for critical care nursing

1998 ◽  
Vol 18 (4) ◽  
pp. 49-54 ◽  
Author(s):  
EJ Bridges ◽  
SL Woods
Keyword(s):  
Critical Care ◽  
Biological Rhythms ◽  
The Body ◽  
Critical Care Nursing ◽  
Endogenous Rhythms ◽  
Physiological Variables ◽  
Need To Evaluate ◽  
Young Subjects ◽  
Cardiovascular Variables

Critical care clinicians must consider known expected circadian rhythms when interpreting fluctuations in patients' hemodynamic values. As noted in the case study, knowledge of circadian rhythmicity in cardiovascular variables may help clinicians anticipate hemodynamic changes and develop and evaluate chronobiologically sensitive interventions, including prescriptions for activity, modification of the timing of medications, and provision of protective interventions for patients with disrupted rhythms. Felver provides excellent guidelines for the systematic review of possible causes for overt changes in circadian patterns. This review highlights the need to evaluate (1) the effect of disease progression on temporal patterns, (2) the patient's underlying endogenous rhythms, (3) the zeitgebers that may entrain the patient's biological rhythms (e.g., light, social cues, and sleep-wake cycles), and (4) how the zeitgebers change in a critical care environment. The body of literature on the rhythmic fluctuation of cardiovascular variables in healthy, young subjects is extensive. During the past 10 years, research on the chronobiologic fluctuations of numerous physiological variables (cardiovascular, pulmonary, hematologic, and endocrine) in critical illness has increased. As information on the fluctuations in critically ill patients increases, critical care clinicians will be challenged to develop and evaluate a chronobiologically sensitive plan of care for these patients.

scholarly journals Laminar pipe flow with time-dependent viscosity

2010 ◽  
Vol 13 (4) ◽  
pp. 729-740 ◽  
Author(s):  
Alan E. Vardy ◽  
James M. B. Brown
Keyword(s):  
General Solution ◽  
Hankel Transform ◽  
Temporal Variations ◽  
Time Dependent ◽  
Pressure Gradients ◽  
Newtonian Viscosity ◽  
Transform Method ◽  
Dependent Viscosity ◽  
Laminar Pipe Flow ◽  
Selection Of

A general solution is obtained for laminar flow in axisymmetric pipes, allowing for prescribed timedependent viscosity and time-dependent pressure gradients. In both cases, the only restriction on the prescribed time dependence is that it must vary continuously; it is not necessary for rates of change to be continuous. The general solution is obtained using the Finite Hankel Transform method. This makes it possible to allow explicitly for time-dependent viscosity, but it does not permit the spatial dependence of viscosity. This contrasts with Laplace transforms, which allow spatial, but not general, temporal variations. The general solution is used to study a selection of particular flows chosen to illustrate distinct forms of physical behaviour and to demonstrate the ease with which solutions are obtained. The methodology is also applied to the simple case of constant (Newtonian) viscosity. In this case, it yields the same solutions as previously published methods, but it does so in a much simpler manner.

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