Dampening Of Amplitude Research Articles

Abstract 2301: Copy number profiling of circulating CD45+/cytokeratin+ cells in a patient with metastatic breast cancer

Abstract Background: In carcinomas, circulating tumor cells (CTCs) are classically defined as nucleated cells with expression of epithelial markers (e.g. cytokeratins (CK)) and lacking expression of the pan-leukocyte marker, CD45. While circulating cells expressing both epithelial and leukocyte markers (double-positive cells, DPs) have also been reported in cancer patients, they are typically excluded from further characterization per this classical definition. The leading hypothesis for the presence of DPs is heterotypical cell fusion between tumor cells and macrophages. However, there is insufficient evidence to exclude alternative biological origins or to demonstrate that patient DPs indeed contain tumor-derived genomes. Here, we examined the clonality and copy number status of DPs together with CTCs from a metastatic breast cancer (MBC) case. Methods: Two blood samples from an ER+/HER2- MBC patient collected prior to and after three weeks of endocrine-based therapy were analyzed. Cells were plated onto glass slides and stained with immunofluorescence antibodies to identify CTCs (DAPI+, CK+, CD45-) and DPs (DAPI+, CK+, CD45+) using a published, enrichment-free detection workflow. Individual cells were then isolated via micro-manipulation and subjected to low-pass whole-genome sequencing for single-cell copy number profiling. Results: Over 3000 CK+ cells were detected per slide analyzed (>6920/mL blood) and approximately 80% were CD45+ (DPs). Copy number profiling of 40 CK+ cells and 3 white blood cell (WBC) controls revealed clonal alterations that were shared across CTCs and DPs, but not WBCs. These included gains and losses on chromosome (chr) 1, loss on chr 4q, a “firestorm”-like signature on chr 8, chr 16p gain, and chr 16q loss. Alteration amplitudes were also consistent between CTCs and DPs, with no indication of amplitude dampening in DPs. Loss of chr X was observed in a subclone of CK+ cells, including 8/18 CTCs and 4/22 DPs. Copy number gain of the PTPRC gene, which encodes for the CD45 protein, was observed across 38/40 CK+ cells and was not associated with CD45 expression. No other CNAs were unique to CTCs or DPs. Conclusions: This is the first direct comparison of DP and CTC copy number profiles from the same patient. We show that DPs share clonal CNAs with CTCs, confirming their tumor lineage. Importantly, DP CNA amplitudes did not exhibit dampening, which would be expected if non-tumor DNA was present, and DP profiles did not contain additional CNAs, which often result when hybrid cells undergo division or ploidy reduction. Ongoing work is focused on proteomic characterization to examine expression of additional leukocyte markers. However, these preliminary results were not consistent with the hypothesis of DPs as tumor-immune cell hybrids and highlights the need for further studies to understand their biological and clinical significance. Citation Format: Nikki Higa, Audrey Limb, Andrés Rivera, Anand Kolatkar, Sara Sakura, Julie Joseph, Margaret Kildee, Lynne Mullican, Craig D. Shriver, James Hicks, Peter Kuhn. Copy number profiling of circulating CD45+/cytokeratin+ cells in a patient with metastatic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2301.

A novel period mutation implicating nuclear export in temperature compensation of the Drosophila circadian clock

Circadian clocks are self-sustained molecular oscillators controlling daily changes of behavioral activity and physiology. For functional reliability and precision, the frequency of these molecular oscillations must be stable at different environmental temperatures, known as "temperature compensation." Despite being an intrinsic property of all circadian clocks, this phenomenon is not well understood at the molecular level. Here, we use behavioral and molecular approaches to characterize a novel mutation in the period (per) clock gene of Drosophila melanogaster, which alters a predicted nuclear export signal (NES) of the PER protein and affects temperature compensation. We show that this new perI530A allele leads to progressively longer behavioral periods and clock oscillations with increasing temperature in both clock neurons and peripheral clock cells. While the mutant PERI530A protein shows normal circadian fluctuations and post-translational modifications at cool temperatures, increasing temperatures lead to both severe amplitude dampening and hypophosphorylation of PERI530A. We further show that PERI530A displays reduced repressor activity at warmer temperatures, presumably because it cannot inactivate the transcription factor CLOCK (CLK), indicated by temperature-dependent altered CLK post-translational modification in perI530A flies. With increasing temperatures, nuclear accumulation of PERI530A within clock neurons is increased, suggesting that wild-type PER is exported out of the nucleus at warm temperatures. Downregulating the nuclear export factor CRM1 also leads to temperature-dependent changes of behavioral rhythms, suggesting that the PER NES and the nuclear export of clock proteins play an important role in temperature compensation of the Drosophila circadian clock.

0860 Burst Suppression due to Diffuse Encephalopathy

Abstract Introduction Burst suppression is a finding on electroencephalography (EEG) associated with a severe encephalopathy associated with coma, severe infantile-onset epilepsy syndromes, hypothermia, or may be medically induced by general anesthesia. It presents as a pattern of alternating high-voltage, 75-250µV, activity separated by periods of amplitude dampening, less than 5µV, of electrical brain activity1. The duration of the burst’s activity is 1-20 seconds while the suppression lasts longer than 10 seconds1. When not medically induced, burst suppression is a known marker of poor prognosis. Report of Cases: An 18-year-old male with cerebral palsy, spastic quadriplegia, and static encephalopathy secondary to hypoxemia ischemic injury in the perinatal period presents with excessive sleepiness during therapy sessions. He was empirically placed on non-invasive ventilatory support with BPAP ST 8/4 cm H2O with a rate of 10 breaths per minute for chronic respiratory failure during sleep. While awake he shows no evidence of hypoxemia or hypercapnia on room air. A polysomnogram was ordered showing moderate obstructive sleep apnea (oAHI 9.73) and central sleep apnea (5.84 events per hour) without hypoxemia (SpO2 nadir 90%), or hypercapnia (TcCO2 max 48 mmHg). The study was scored as REM/NREM as specific sleep architecture was not identified. Diffuse burst suppression was observed. No epileptiform abnormalities were recorded. A MRI of the brain shows diffuse encephalomalacia involving the supratentorial brain parenchyma with volume loss of the cerebellum, the pons, and brain stem. Conclusion The abnormal brain activity noted in our patient is due to underlying encephalomalacia and diffuse brain injury secondary to his perinatal hypoxemic ischemic injury. Despite his significant underlying neurological abnormality, he can maintain adequate ventilation and oxygenation while awake. While asleep, he has moderate obstructive and central sleep apnea without hypoxemia or hypercapnia. This is likely due to the activity of control centers of respiration being spared despite the volume loss noted on the brain MRI. Support (If Any)

Coupled heat and moisture transfer model to evaluate earth-to-air heat exchangers exposed to harmonically fluctuating thermal environments

The heat and moisture transfer process of an earth-to-air heat exchangers (EAHE) determines its ability to cool/heat an indoor environment. In humid climates, the moisture content of the EAHE inlet air is relatively high and exhibits a different fluctuation behavior than the air dry bulb temperature. In this study, a mathematical model was accordingly developed to evaluate the coupled heat and moisture transfer in an EAHE. Two prerequisites were considered by the model: the inlet was exposed to both harmonically fluctuating outdoor air temperature and moisture content, and the surface of the EAHE was directly formed by the surrounding material and always saturated due to water infiltration from this material. Based on the harmonic analytical method and a numerical approach, solutions for the amplitude dampening and phase-shifting of air temperature and moisture content were obtained. The model was validated using the results of well-regulated experiments, which indicated that phase-shifting and amplitude dampening of both air temperature and moisture content fluctuations occur in an EAHE. The coupled heat and moisture transfer between the humid air and the wet EAHE walls was found to intensify the phase shift but considerably attenuates the air enthalpy fluctuation amplitude. Then, application examples were analyzed corresponding to typical humid and dry cities-Chongqing and Beijing, respectively. The results showed the normalized fluctuation amplitude of the outlet air enthalpy for the Chongqing and Beijing environments decreased by 56.7 % and 61.1 %, respectively, indicating that moisture transfer considerably influences the air enthalpy fluctuation at the EAHE outlet.

Assessing the Impact of a Heated Basement on Groundwater Temperatures in Bratislava, Slovakia.

Groundwater temperature is a useful hydrogeological parameter that is easy to measure and can provide much insight into groundwater flow systems, but can be difficult to interpret. For measuring temperature directly in the ground, dedicated specifically designed monitoring wells are recommended since conventional groundwater wells are not optimal for temperature monitoring. Multilevel monitoring of groundwater temperature is required to identify contributions of different possible heat inputs (sources) on measured temperature signals. Interpreting temperature data as a cosine function, including period, average temperature, amplitude, and phase offset, is helpful. Amplitude dampening and increasing phase shift with distance from a boundary can be used for estimation of transport parameters. Temperature measurements at different depths can be used for evaluation of unknown parameters of analytical functions by optimization of regression fits in Python. These estimated parameters can be used to calculate temperatures at known water table depths which can be applied as a fixed transient boundary condition in MT3DMS to overcome the limitations of MT3DMS heat transport modeling in the unsaturated zone. In this study, temperature monitoring and modeling was used to evaluate the influence of a department store's heated basement foundation on groundwater temperature within a green space (city park), with the main outcome that 17 years after construction, the department store foundation has increased the mean groundwater temperature by 3.2 °C. Heat input evaluated by the MT3DMS model varied from 0.1W/m2 at a distance of 100 m up to 12 W/m2 next to the building.

Recharge and dynamics of a karst groundwater system in Kakheti (Eastern Georgia)

Abstract Monitoring temporal variations of 18O and 2H isotopes in precipitation, groundwater and surface water was performed in the region of Kakheti (East Georgia). Data were collected from three meteorological stations at altitudes between 400 - 1,100 m a.s.l., from two shallow and one deep hydrogeological boreholes, and from two surface water monitoring stations (Alazani River and Patmasuri karstic stream). 18O values in precipitation show an annual variation between -22 ‰ and +1 ‰ and a distinct altitude effect. A clear correlation exists between the seasonal isotope composition of precipitation, shallow groundwater and surface water. A five-fold amplitude dampening and a delay of 10-15 days was observed. The data show that precipitation in the Caucasus Mountains to the North infiltrates into the Upper Jurassic - Lower Cretaceous karstic aquifer and travels to the Alazani valley towards south-east. The isotopic signature of winter precipitation is reflected in stream water as well as in shallow groundwater isotope data of groundwater in a 2,000-m-deep hydrogeological borehole at Heretiskari show a distinctly different character with δ18O ranging between -2.8 ‰ to -2.2 ‰ and a deuterium excess of -25 ‰.

Spatial and temporal variation in the range-wide cyclic dynamics of greater sage-grouse.

Periodic changes in abundance, or population cycles, are common in a variety of species and is one of the most widely studied ecological phenomena. The strength of, and synchrony between population cycles can vary across time and space and understanding these patterns can provide insight into the mechanisms generating population cycles and their variability within and among species. Here, we used wavelet and spectral analysis on a range-wide dataset of abundance for the greater sage-grouse (Centrocercus urophasianus) to test for regional differences in temporal cyclicity. Overall, we found that most populations (11 of 15) were cyclic at some point in a 50-year time series (1965-2015), but the patterns varied over both time and space. Several peripheral populations demonstrated amplitude dampening or loss of cyclicity following population lows in the mid-1990s. Populations through the core of the range in the Great and Wyoming Basins had more consistent cyclic dynamics, but period length appeared to shorten from 10-12 to 6-8years. In one time period, where cyclicity was greatest overall, increased pairwise population synchrony was correlated with cycle intensity. Our work represents a comprehensive range-wide assessment of cyclic dynamics and revealed substantial variation in temporal and spatial trends of cyclic dynamics across populations.

Clock-Enhancing Small Molecules and Potential Applications in Chronic Diseases and Aging.

Normal physiological functions require a robust biological timer called the circadian clock. When clocks are dysregulated, misaligned, or dampened, pathological consequences ensue, leading to chronic diseases and accelerated aging. An emerging research area is the development of clock-targeting compounds that may serve as drug candidates to correct dysregulated rhythms and hence mitigate disease symptoms and age-related decline. In this review, we first present a concise view of the circadian oscillator, physiological networks, and regulatory mechanisms of circadian amplitude. Given a close association of circadian amplitude dampening and disease progression, clock-enhancing small molecules (CEMs) are of particular interest as candidate chronotherapeutics. A recent proof-of-principle study illustrated that the natural polymethoxylated flavonoid nobiletin directly targets the circadian oscillator and elicits robust metabolic improvements in mice. We describe mood disorders and aging as potential therapeutic targets of CEMs. Future studies of CEMs will shed important insight into the regulation and disease relevance of circadian clocks.

Evaluation of the thermal performance of an earth-to-air heat exchanger (EAHE) in a harmonic thermal environment

The earth-to-air heat exchanger (EAHE) is a low-energy device used to improve the thermal condition of buildings, which is filled with the air directed from the outside and surrounded by the soil. The temperatures of both the air and soil are periodically fluctuating, leading to the EAHEs working in a harmonic thermal environment. However, most of the previous theoretical studies investigated the performance of EAHEs by ways of static and steady-state models, paying insufficient attention to the temperature phase shifting and fluctuation attenuation effects. The main purpose of this work is to develop an approach to predict the performance of EAHE subjected to harmonic thermal environments. The harmonic temperature signals transmitted from both the pipe inlet and the ground surface are incorporated in the model by means of the ‘excess fluctuating temperature’. The amplitude dampening and phase-shifting of the EAHE air temperature for both annually and daily fluctuating cycles are derived as explicit expressions. The analytical results are validated against numerical simulations. The model is applied in a hot-summer/cold-winter region. Results indicate that a deep-buried EAHE pipe can reduce the air temperature by 7°C on a summer day. The maximum cooling or heating capacities occur in spring/summer or autumn/winter transitional seasons. The use of an EAHE pipe can create a 3000-W cooling or heating capacity.

Long‐term pattern of population dynamics in the field vole from central Europe: cyclic pattern with amplitude dampening

AbstractThe subject of population cycles is regarded as controversial due to a number of unsettled questions such as whether or not cyclic patterns are governed by the same processes at high and low latitudes in Europe. Recent evidence suggests that the dynamics at high and low latitudes share the common temporal pattern of vole dynamics referred to as collapsing population cycles. Despite concurrent interest, the key contention around the causal mechanisms that drive population cycles remains a hot topic in ecology. The aims of this study are to supplement information on the seasonal population dynamics of the field vole Microtus agrestis in the Czech Republic by analysing 25 years of time series data. By applying robust estimation procedures, we estimated several parameters to describe population dynamics, such as population variability, amplitude dampening, cycle period, order of the dynamics and the structure of density dependence. The parameters indicate that field vole dynamics in central Europe are highly variable, cyclic dynamics of order two, with peaks in abundance occurring regularly at intervals of 4–5 years. In addition to exhibiting population cycles, the field vole populations show a pattern of dampened amplitude as observed elsewhere in Europe, including northern latitudes. By analysing temporal trends in seasonal abundances, population growth rates and environmental temperatures, we did not obtain evidence to support the hypothesis that amplitude dampening results from the negative effect of increasingly mild winters on winter population growth rates.

Alterations of the Characteristics of the Circadian Rest‐Activity Rhythm of Cancer In‐Patients

The aim of the present study was to evaluate the characteristics of the circadian rest‐activity rhythm of cancer patients. Thirty‐one in‐patients, consisting of 19 males and 12 females, were randomly selected from the Regional Cancer Center, Pandit Jawaharlal Nehru Medical College, Raipur, India. The rest‐activity rhythm was studied non‐invasively by wrist actigraphy, and compared with 35 age‐matched apparently healthy subjects (22 males and 13 females). All subjects wore an Actiwatch (AW64, Mini Mitter Co. Inc., USA) for at least 4–7 consecutive days. Fifteen‐second epoch length was selected for gathering actigraphy data. In addition, several sleep parameters, such as time in bed, assumed sleep, actual sleep time, actual wake time, sleep efficiency, sleep latency, sleep bouts, wake bouts, and fragmentation index, were also recorded. Data were analyzed using several statistical techniques, such as cosinor rhythmometry, spectral analysis, ANOVA, Duncan's multiple‐range test, and t‐test. Dichotomy index (I<O) and autocorrelation coefficient (r24) were also computed. The results validated a statistically significant circadian rhythm in rest‐activity with a prominent period of 24 h for most cancer patients and control subjects. Results of this study further revealed that cancer patients do experience a drastic alteration in the circadian rest‐activity rhythm parameters. Both the dichotomy index and r24 declined in the group of cancer patients. The occurrence of the peak (acrophase, Ø) of the rest‐activity rhythm was earlier (p<0.001) in cancer patients than age‐ and gender‐matched control subjects. Results of sleep parameters revealed that cancer patients spent longer time in bed, had longer assumed and actual sleep durations, and a greater number of sleep and wake bouts compared to control subjects. Further, nap frequency, total nap duration, average nap, and total nap duration per 1 h awake span were statistically significantly higher in cancer patients than control subjects. In conclusion, the results of the present study document the disruption of the circadian rhythm in rest‐activity of cancer in‐patients, with a dampening of amplitude, lowering of mean level of activity, and phase advancement. These alterations of the circadian rhythm characteristics could be attributed to disease, irrespective of variability due to gender, sites of cancer, and timings of therapies. These results might help in designing patient‐specific chronotherapeutic protocols.