Multiscale Equation-Based Models: Insights for Inflammation and Physiological Variability

Author(s):  
Jeremy D. Scheff ◽  
Steve E. Calvano ◽  
Ioannis P. Androulakis
Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Thomas A Kent ◽  
Harriett C Rea ◽  
William Dalmeida ◽  
Roderic H Fabian ◽  
Cenk Ayata ◽  
...  

Introduction: Failures to translate pre-clinical results have been discouraging. We have contended that stroke is too heterogeneous with respect to factors influencing outcome to expect small studies to be balanced. It is not only difficult to control for biological and methodological variability but efforts to improve homogeneity, such as minimizing physiological variability, may render results less applicable to humans. Here, we report a predictive outcome model in experimental stroke which incorporates baseline variability and provides statistical thresholds a treatment must exceed to be efficacious in a broad population. Methods: We generated a mathematical model to predict outcome using transient MCA occlusion in 23 unfasted rats. To create baseline variability, we varied occlusion times from 90-120 min, altered baseline glucose with streptozotocin, and assessed neurological outcome 3 days later with a modified Bederson Score (BS; 0-6 functional measure, 7 death). Statistical surfaces in 3 dimensions were generated using Jacobian matrices flanking the model to provide a screening threshold (1 SD) for comparing new therapies against this model. Results: We successfully generated an outcome model from occlusion time, glucose and BS (Fig; R 2 =.49, p=.0003; middle surface is the model surrounded by ±SD surfaces). Outcome was sensitive to change in glucose and time, suggesting small imbalances in these factors between groups may influence outcome, and hence the perceived efficacy of a new therapeutic intervention. At normoglycemia and 90 mins, the lower surface overlapped with no deficit, indicating it would be difficult to reliably demonstrate benefit under those conditions. Conclusions: These results indicate it is feasible to incorporate biological variability to generate more clinically relevant conditions. The method will be tested with other stroke models and modifiers towards a generalized model to screen for therapies worthy of further study.


2016 ◽  
Vol 4 (11) ◽  
pp. 808-817
Author(s):  
Najibullah Rahmatzai ◽  
◽  
AhmedA. Zaitoun ◽  
MohamedHussein Madkour ◽  
Abdullah Ahmady ◽  
...  

2000 ◽  
Vol 203 (11) ◽  
pp. 1733-1740 ◽  
Author(s):  
B. Bagatto ◽  
D.A. Crossley ◽  
W.W. Burggren

The role of genetics on neonatal physiological variability was examined in the nine-banded armadillo (Dasypus novemcinctus). Since armadillos give birth to only monozygous quadruplets, the genetic variation within litters is essentially zero. Quadruplets born in captivity were isolated and weighed within 8 h of birth. Oxygen consumption (V.(O2)) was measured in resting neonates by flow-through respirometry, heart rate obtained from an electrocardiogram and ventilation was measured by impedance techniques. Following the measurements, neonates were returned to the mother. Measurements were repeated at 4 and 8 days after birth. Mean heart rate significantly increased from 132 beats min(−1) on the day of birth to 169 beats min(−1) on day 8. Mean ventilation rate significantly decreased from 81 breaths min(−1) on the day of birth to 54 breaths min(−1) on day 8. During this same developmental period, mean mass significantly increased from 100 g to 129 g, and mean mass-specific oxygen consumption significantly decreased from 32.2 ml O(2)kg(−1)min(−1) to 28.6 ml O(2)kg(−1) min(−1). For all variables measured, within-litter variability was always significantly less than between-litter variability, confirming a ‘sibling effect’ that we attribute to the genetic components determining physiological characters.


2000 ◽  
Vol 88 (5) ◽  
pp. 1924-1932 ◽  
Author(s):  
Shu Zhang ◽  
Peter A. Robbins

Measurement of the acute hypoxic ventilatory response (AHVR) requires careful choice of the hypoxic stimulus. If the stimulus is too brief, the response may be incomplete; if the stimulus is too long, hypoxic ventilatory depression may ensue. The purpose of this study was to compare three different techniques for assessing AHVR, using different hypoxic stimuli, and also to examine the between-day variability in AHVR. Ten subjects were studied, each on six different occasions, which were ≥1 wk apart. On each occasion, AHVR was assessed using three different protocols: 1) protocol SW, which uses square waves of hypoxia; 2) protocol IS, which uses incremental steps of hypoxia; and 3) protocol RB, which simulates an isocapnic rebreathing test. Mean values for hypoxic sensitivity were 1.02 ± 0.48, 1.15 ± 0.55, and 0.93 ± 0.60 (SD) l ⋅ min− 1 ⋅ %− 1for protocols SW, IS, and RB, respectively. These differed significantly ( P < 0.01). The coefficients of variation for measurement of AHVR were 20, 23, and 36% for the three protocols, respectively. These were not significantly different. There was a significant physiological variation in AHVR ( F 50,100 = 3.9, P < 0.001), with a coefficient of variation of 26%. We conclude that there was relatively little systematic variation between the three protocols but that AHVR varies physiologically over time.


1992 ◽  
Vol 38 (6) ◽  
pp. 864-872 ◽  
Author(s):  
S D Kafonek ◽  
C A Derby ◽  
P S Bachorik

Abstract We determined the physiological variability of total cholesterol, high- (HDL) and low-density lipoprotein (LDL) cholesterol, triglycerides, and apolipoproteins A-I and B in fasting blood samples from patients referred to the Johns Hopkins Lipid Referral Clinic. Samples were taken on each of three occasions during baseline evaluation visits before the patients were treated. The median physiological coefficients of variation (CVp) were as follows: total cholesterol, 5.0%; triglycerides, 17.8%; HDL cholesterol, 7.1%; LDL cholesterol, calculated from the previous three measurements, 7.8%; and apolipoproteins A-I and B, 7.1% and 6.4%, respectively. There were no significant differences in CVp between children (less than or equal to 18 years) and adults (greater than 18 years) for any of the measurements. On the basis of our findings, single measurements in serial samples taken on three occasions suffice to establish the patients' usual values with the following precisions (+/- 1 CV): total cholesterol, +/- 4%; triglycerides, +/- 11%; HDL cholesterol, +/- 8%; LDL cholesterol, +/- 6%; and apolipoproteins A-I and B, +/- 7%.


2017 ◽  
Vol 10 (1) ◽  
pp. 117-124
Author(s):  
SK Mondal ◽  
MM Rahman

The experiment was conducted to find out the morpho-physiological variability in response to different sowing dates in four lines of Quality Protein Maize (QPM) in in the Field Laboratory of the Department of Crop Botany, Bangladesh Agricultural University, Mymensingh. The study was carried out with four lines of maize and two sowing dates, 15 November (T1) and 15 December, ((T2). Sowing date differed significantly in plant height, length of leaf blade, length of leaf sheath, leaf breadth, cob length, cob diameter, length of tassel, days to 50% tasselling, days to 50 % silking, days to maturity, number of cobs per plant, cob weight, number of grain per cob. 1000-seed weight, percent underdeveloped cob, total dry matter and grain yield, but did not differ in number of leaves and protein percent. The lines differed significantly among themselves in those characters except number of leaves per plant, length of leaf sheath, cob length, cob diameter, days to 50% tasselling, number of cobs per plants and number of grain per cob. The line Across 8666 (V2) and (V3) gave the highest grain yield 4.57 and 4.55 and the lowest from (V4) lines 4.41 tons per hectare. The 15 November sowing time (T1) gave the highest grain yield 4.86 tons per hectare. In case of interaction, the earlier planting time (T1) showed better performance with all lines. On the other hand, the highest yield was found from combination of line V2 and V3 with earlier planting time (T1).J. Environ. Sci. & Natural Resources, 10(1): 117-124 2017


Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2063
Author(s):  
Marian Kuczaj ◽  
Anna Mucha ◽  
Alicja Kowalczyk ◽  
Ryszard Mordak ◽  
Ewa Czerniawska-Piątkowska

The aim of the study was to determine the effect of the number and stage of lactations, time of day and calving season of cows on milk yield from a single milking, average milking time, average milking per minute, daily milking frequency and the relationship between the tested parameters of quarter milking. The study included a herd of 65 Polish Holstein Friesian black and white cows used in a free-range barn located in south-west Poland. The animals were kept in proper welfare conditions, fed using the partly mixed ration (PMR) method on the feeding table. The milk was obtained using the Lely-Astronaut A4 Automatic Milking System (AMS). The animals on the dairy cattle farm were used in the range from the first to the seventh lactation, i.e., at the age of 2.0 to approximately 10 years. In this study, the amount of milk yielded from the hind quarters was statistically significantly higher (p < 0.05) than the trait determined for the front quarters. At the same time, the milk flow rate was statistically significantly higher (p < 0.05) in the front quarters compared to the rear quarters. The daily milk yield in right rear (RR) and left rear (LR) hind quarters was higher by 1.0 kg of milk, respectively, than in right front (RF) and left front (LF) fore quarters. The milking time of the RR and LR hind quarters during the day was longer by 104.9 and 128.8 s, respectively, than the RF and LF fore quarters. The milking speed of the RR and LR hind quarters during the day was lower by 0.2 and 1.12 g/s, respectively, than in the RF and LF fore quarters. The values of the correlation between the yields of milk and its components obtained in this study were high and positive. Correlations between the milk yield and the content of its components were negative. The obtained results confirmed that the natural physiological variability of the udder and teats structure, as well as the course of lactation, significantly affects the individual composition and milk flow during milking. The ability to regulate the milk flow by adjusting the appropriate negative pressure during the robot’s operation, in the observed variability of individual lobes of the mammary gland, increases the efficiency of milking and, as a result, reduces the risk of mastitis in cows.


2008 ◽  
Vol 54 (3) ◽  
pp. 223-230 ◽  
Author(s):  
Rajesh Kumar Jain ◽  
Vineet Sinha ◽  
Gouri V Sawant ◽  
T S Ananthakrishanan ◽  
Nirupama Mishra ◽  
...  

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