Electrophysiological Differences in the CPG Aerial Respiratory Behavior Between Juvenile and Adult Lymnaea

2003 ◽  
Vol 90 (2) ◽  
pp. 983-992 ◽  
Author(s):  
Chlöe McComb ◽  
Ryanne Meems ◽  
Naweed Syed ◽  
Ken Lukowiak
Keyword(s):  
Volume Ratio ◽  
Rhythmic Activity ◽  
Membrane Resistance ◽  
Synaptic Connectivity ◽  
Aerial Respiration ◽  
Respiratory Rhythmogenesis ◽  
Age Related ◽  
Respiratory Behavior ◽  
The Difference ◽  
Cutaneous Respiration

Intact, freely moving juvenile Lymnaea perform aerial respiration significantly less often than do adults. We therefore hypothesized that RPeD1, the central pattern generator (CPG) neuron that initiates rhythmogenesis, would be less active in juveniles than adults. Using both isolated and semi-intact preparations to directly test this hypothesis, we found the opposite; juvenile RPeD1s were significantly smaller and more excitable than RPeD1s from adults. Significant age-related differences were found in the membrane resistance (greater in juveniles), time constant (smaller in juveniles), and rheobase current (lower in juveniles), all of which would tend to make juvenile cells significantly more excitable. However, there were significant age-related differences in the synaptic connectivity within the CPG and in peripheral input to the CPG, all which favor more rhythmic activity in the adult CPG. As was the case for intact Lymnaea, juvenile semi-intact preparations perform aerial respiration less often than do adults. The difference in excitability between juvenile and adult RPeD1s is therefore not sufficient to cause increased rhythmogenesis. Age-related changes in synaptic connectivity within the respiratory CPG and in peripheral modulation allow respiratory rhythmogenesis to be more easily expressed in adults which may compensate for their decreased dependence on cutaneous respiration as their surface to volume ratio changes as the grow in size.

Beta-adrenergic modulation of Na-K pump activity in young and adult canine cardiac Purkinje fibers

1996 ◽  
Vol 271 (2) ◽  
pp. H706-H712
Author(s):  
F. Charpentier ◽  
M. J. Legato ◽  
S. F. Steinberg ◽  
I. S. Cohen ◽  
M. R. Rosen
Keyword(s):  
Cell Surface ◽  
Volume Ratio ◽  
Beta Adrenergic ◽  
Purkinje Fibers ◽  
Age Related ◽  
Cardiac Purkinje Fibers ◽  
Adrenergic Modulation ◽  
Pump Activity ◽  
The Difference ◽  
Beta Adrenergic Agonist

We used standard microelectrode techniques to study the developmental changes and beta-adrenergic modulation of membrane potential and of Na-K pump activity in adult (> 1 yr of age) and neonatal (2-10 days) canine Purkinje fibers. Isoproterenol (10(-7) M) increased the rate of development and magnitude of pacing-induced hyperpolarization of adult fibers driven at a 1-s cycle length. This effect of isoproterenol was attenuated by treating dogs with pertussis toxin (PTX), (30 micrograms/kg). Other adult and neonatal fibers were superfused with a Tyrode solution containing Ba2+ 0.2 mM, Cs+ 2 mM, and 10(-6) M verapamil, thus leading to depolarization and cessation of spontaneous activity. The Na-K pump was studied by alternating solutions containing [K] at 0 mM (inhibiting the pump) and 4 mM (reactivating the pump). Although the kinetics of the Na-K pump appeared faster in neonatal fibers than in adult fibers, measurement of cell surface-to-volume ratio compensated for the difference. We therefore conclude that 1) the apparent age-related changes in Na-K pump activity in canine Purkinje fibers in fact reflect cell surface-to-volume ratio and, 2) the beta-adrenergic agonist-induced hyperpolarization in adults requires the presence of a PTX-sensitive G protein for its occurrence.

scholarly journals Effect of Leukoreduction on Hematobiochemical Parameters and Storage Hemolysis in Canine Whole Blood Units

Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 925
Author(s):  
Maria Teresa Antognoni ◽  
Maria Luisa Marenzoni ◽  
Ambra Lisa Misia ◽  
Luca Avellini ◽  
Elisabetta Chiaradia ◽  
...  
Keyword(s):  
Whole Blood ◽  
Complete Blood Count ◽  
Membrane Resistance ◽  
Progressive Increase ◽  
Rbc Membrane ◽  
Morphological Index ◽  
The Difference ◽  
Hematobiochemical Parameters ◽  
And Storage ◽  
Individual Donor

Storage lesions (SLs) occur when the red blood cell quality is altered during the preservation of blood units. Pre-storage leukoreduction would limit the number of SLs. The aims of this study were to evaluate the effectiveness of a leukoreduction filter for human use and the effect of pre-storage leukoreduction on some ematobiochemical parameters in stored canine whole blood. Seven canine blood units were tested. Each one was divided into two units—one leukoreduced (LRWB) and one non-leukoreduced (nLRWB). On each unit, we determined the complete blood count (CBC), lactate-dehydrogenase (LDH), electrolytes (Na+, K+, Cl−), morphological index (MI) and hemolysis, on storage days 0, 7, 14, 21, 28, 35, and 42. Leukoreduction allowed a 98.30% recovery of the RBC count, retaining 99.69% and 94.91% of WBCs and PLTs, respectively. We detected a significant increase of LDH and MI with strongly higher values in nLRWB compared to LRWB. A progressive increase in electrolytes and LDH concentrations was observed as indices of stored hemolysis. LDH showed significantly lower values in LRWB units compared to nLRWB, suggesting its release from leukocytes. In the majority of units, hemolysis reached 1% on the 42nd day of storage. We assert the human leukoreduction filter effectiveness on canine whole blood, and we recommend using nLRWB before day 14, especially for critically ill patients. The difference of the basal hemolysis (day 0) percentages observed between subjects suggests that more studies should be performed to confirm a possible inter-individual donor biological variability of RBC membrane resistance, as happens in humans.

Structure and electrical properties of eye muscles in cave- and surface-dwelling crayfishes

1980 ◽  
Vol 84 (1) ◽  
pp. 187-199
Author(s):  
D. Mellon ◽  
G. Lnenicka
Keyword(s):  
Input Resistance ◽  
Selective Advantage ◽  
Oculomotor System ◽  
Membrane Resistance ◽  
Muscle Fibres ◽  
Cross Sectional ◽  
Eye Muscles ◽  
Current Voltage ◽  
The Difference ◽  
Cave Dweller

The morphologies and passive electrical parameters of fibres in two eye muscles of a surface- and a cave-dwelling crayfish were compared. In the cave-dwelling form the muscles contained fewer fibres, of less diameter, and hence had a smaller cross-sectional area. Current-voltage relationships were similar in both species. Input resistance was higher in the cave-dweller, but the difference was not as great as would be expected on the basis of geometry alone. Accordingly, the specific membrane resistance of muscle fibres in the cave-dweller is 50–60% smaller than that in the surface-dweller. This may account partially for the observation that identified excitatory junctional potentials in muscles of cave- and surface dwellers have similar amplitudes. We conclude that a functional oculomotor system is maintained in cave-dwelling crayfish, and that this system confers some positive selective advantage.

Fluid Flow and Heat Transfer of Liquid Sodium in Small-Scale Heat Sinks With Different Geometries

2021 ◽  
Author(s):  
Mahyar Pourghasemi ◽  
Nima Fathi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Cross Sections ◽  
Heat Sink ◽  
Volume Ratio ◽  
Heat Sinks ◽  
Liquid Sodium ◽  
Small Scale ◽  
Nusselt Numbers ◽  
The Difference

Abstract 3-D numerical simulations are performed to investigate liquid sodium (Na) flow and the heat transfer within miniature heat sinks with different geometries and hydraulic diameters of less than 5 mm. Two different straight small-scale heat sinks with rectangular and triangular cross-sections are studied in the laminar flow with the Reynolds number up to 1900. The local and average Nusselt numbers are obtained and compared against eachother. At the same surface area to volume ratio, rectangular minichannel heat sink leads to almost 280% higher convective heat transfer rate in comparison with triangular heat sink. It is observed that the difference between thermal efficiencies of rectangular and triangular minichannel heat sinks was independent of flow Reynolds number.

Ingestion rate and body size in phagotrophic organisms

1990 ◽  
Vol 68 (2) ◽  
pp. 313-317 ◽  
Author(s):  
Gerard M. Capriulo ◽  
David Lints ◽  
Martin Lewinter
Keyword(s):  
Body Weight ◽  
Functional Relationship ◽  
Ingestion Rate ◽  
Volume Ratio ◽  
Functional Design ◽  
Physiological Constraints ◽  
Unit Body Weight ◽  
The Difference ◽  
Log Linear ◽  
Physical Phenomena

A general functional relationship between body weight (10−11 to 108 g) and ingestion rate has been found to exist throughout the protistan and metazoan kingdoms. Results, based on a mathematical interpretation of standardized, quantitative data, indicate that ingestion rate is a log–log linear function (i.e., power function) of body weight (I = a W0.829 for cold-blooded forms and I = a W0.778 for warm-blooded forms, where I = ingestion rate and W = body weight). The slopes of the cold-blooded and warm-blooded regression lines are not significantly different from each other (i.e., they are parallel). This allows one to use the difference between the respective curves to estimate the weight-specific cost of warm-bloodedness. Such an analysis of the data indicates that a warm-blooded organism must ingest about ten times more food per unit body weight than cold-blooded forms. This functional relationship may be a manifestation of the physiological constraints placed on organisms by surface area to volume ratio phenomena, related to absorptive surfaces, mouth areas, and body volumes. The present analysis suggests that flexibility in functional design is limited by physical phenomena which affect phenotypic plasticity.

scholarly journals Redox Index of Cys-Thiol Residues of Serum Apolipoprotein E and Its Diagnostic Potential

2021 ◽  
Author(s):  
Kazuyoshi Yamauchi ◽  
Yasushi Kawakami
Keyword(s):  
Apolipoprotein E ◽  
Serum Triglyceride ◽  
Redox Status ◽  
Reduced Form ◽  
Band Shift ◽  
Redox Biology ◽  
Age Related ◽  
Diagnostic Potential ◽  
The Difference ◽  
Hba1c Levels

Abstract We explored the proper index for estimating the redox status of Cys-thiol of serum apolipoprotein E (apoE), named “redox-IDX-apoE,” which is necessary to understand the redox biology of age-related diseases, such as atherosclerosis. The fractions of reduced form (red-), reversible oxidized form (roxi-), and irreversibly oxidized form (oxi-) apoE were measured by a band-shift assay. Candidates of redox-IDX-apoE were determined by calculating the values of these fractions and total apoE concentration. The ratios of roxi-apoE to total-apoE (roxi/total), red-apoE to roxi-apoE (red/roxi), and [red-apoE + oxi-apoE] to roxi-apoE ([red + oxi]/roxi) were independent of age and sex. Roxi/total showed significant negative correlations with serum triglyceride (TG) and HbA1c levels, while red/roxi and [red + oxi]/roxi showed significant positive correlations with them. However, red/roxi and [red + oxi]/roxi in the patients with atherosclerosis were significantly lower than those in control subjects, although serum TG and HbA1c levels in the patients were significantly higher than those in controls. The redox status of serum apoE-Cys-thiol is closely involved in the metabolism of TG-rich lipoproteins and glucose and may vary depending on the difference in pathological conditions. The appropriate usage of these ratios could be helpful in the diagnosis and prognosis of age-related diseases.

scholarly journals A cross-sectional study on interference control: age affects reactive control but not proactive control

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8365 ◽  
Author(s):  
Yanfang Peng ◽  
Qin Zhu ◽  
Biye Wang ◽  
Jie Ren
Keyword(s):  
Middle Ages ◽  
Middle Age ◽  
The Elderly ◽  
Efficiency Score ◽  
Interference Control ◽  
Reactive Control ◽  
Cross Sectional ◽  
Age Related ◽  
The Difference ◽  
The Impact

Background Working memory updating (WMU), a controlled process to continuously adapt to the changing task demand and environment, is crucial for cognitive executive function. Although previous studies have shown that the elderly were more susceptible to cognitive interference than the youngsters, the picture of age-related deterioration of WMU is incomplete due to lack of study on people at their middle ages. Thus, the present study investigated the impact of age on the WMU among adults by a cross-sectional design to verify whether inefficiency interference control accounts for the aging of WMU. Methods In total, 112 healthy adults were recruited for this study; 28 old adults (21 female) ranging from 60 to 78 years of age; 28 middle-age adults (25 female) ranging from 45 to 59 years of age; 28 adults (11 female) ranging from 26 to 44 years of age; and 28 young adults (26 female) ranging from 18 to 25 years of age. Each participant completed a 1-back task. The inverse efficiency score was calculated in various sequences of three trials in a row to quantify the performance of WMU for adults of various ages. Results Inverse efficiency score of both young groups (young adult and adult) were significantly shorter than the old group in both Repeat-Alternate (RA, including □□○ and ○○□) and Alternate-Alternate (AA, including ○□○ and □○□) sequential patterns and they were additionally better than the middle-age group in AA sequential pattern. Conclusion With the increase of difficulty in the task, the difference in reactive interference control between young and middle age was gradually revealed, while the difference between young and old remained to apparent. The degradation of WMU aging may begin from middle-age and presents selective impairment in that only reactive interference control, but not proactive interference control, shows pronounced age-related decline. The preliminary results can inform future studies to further explore the whole lifespan trajectories of cognitive functions.

scholarly journals Ultrastructure changes and expression of NLRP3 inflammasome  in lens anterior capsule of patient with cataracts associated with uveitis

2019 ◽  
Author(s):  
Chu Zhang ◽  
Chong-Hui Ying ◽  
siqin Sun ◽  
yuechun Wen ◽  
Zicheng Zhu
Keyword(s):  
Epithelial Cells ◽  
Ultrastructural Changes ◽  
Lens Epithelial Cells ◽  
Control Group ◽  
Anterior Capsule ◽  
Caspase 1 ◽  
Pyrin Domain ◽  
Age Related ◽  
The Difference ◽  
Domain 3

Abstract ● AIM : T o investigate the expression of nod-like receptor pyrin domain 3 (NLRP3) in lens anterior capsule of Uveitis associated with cataract and observe the ultrastructural changes of them . ● Methods: 17(22 eyes) cases of uveitis associated with cataract were selected a s experimental group and 1 0 (18 eyes) cases of age-related cataract were selected a s contro l group. The expressions of NLRP3, apoptosis-related speckle protein （ASC） and caspase-1 protein were tested by immunohistochemical and the ultrastructural changes of anterior capsul e was observed under electron microscope. ● Results: The expression of NLRP3 、 caspase-1 and ASC in the anterior capsu le of cataracts associated with uveitis was significantly higher than that of the control group, the difference was statistically significant (p ＜ 0.05). The apoptotic changes of lens epithelial cells in uveitis associated with cataract were obvious, and the apoptotic changes of lens epithelial cells were mild in age-related cataract patients. ● Conclusion: Strongly postive expressed NLRP3 inflamma some and obvious apoptotic changes are founded in the lens epithelial cells of patients with uveitis associat ed with cataract, suggesting that NLRP3 inflamma some and the apoptosis of lens epithelial cells may play a role in the progress of uveitis associat ed with cataract.

Self-employment and earning inequality

2007 ◽  
pp. 106
Author(s):  
Jean-Marc Falter
Keyword(s):  
Work Experience ◽  
Factors Affecting ◽  
Self Employment ◽  
Employment Sector ◽  
Age Related ◽  
Wage Employment ◽  
The Difference ◽  
Income Dispersion ◽  
Two Sectors ◽  
Earning Inequality

The present study attempts to explain the difference in observed earning inequality between self-employment and wage-employment in Switzerland in 1992, 1995 and 2000. We use several measures of inequality in order both to determine the factors affecting income dispersion in the two groups and to identify the variables that drive the earning inequality differential. Thus, we make use of discrete decomposition techniques and of a regression-based method. The latter allows us to introduce a selection term in our decompositions which is of crucial importance in the case of self-employment. Our results indicate that education- and age-related variables, like work experience and tenure, are the most important factors explaining the inequality level in both groups. The importance of these factors seems, however, to be larger in the wage-employment sector. The reason may lie in the process of selection into selfemployment rather than in the differences in the returns to characteristics between the two sectors.

scholarly journals Improved relapse recovery in paediatric compared to adult multiple sclerosis

Brain ◽  
2020 ◽  
Vol 143 (9) ◽  
pp. 2733-2741
Author(s):  
Tanuja Chitnis ◽  
Greg Aaen ◽  
Anita Belman ◽  
Leslie Benson ◽  
Mark Gorman ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Functional System ◽  
Progressive Multiple Sclerosis ◽  
Age Related ◽  
Younger Age ◽  
Disability Status ◽  
The Us ◽  
The Difference ◽  
Effect Of Age

Abstract Incomplete relapse recovery contributes to disability accrual and earlier onset of secondary progressive multiple sclerosis. We sought to investigate the effect of age on relapse recovery. We identified patients with multiple sclerosis from two longitudinal prospective studies, with an Expanded Disability Status Scale (EDSS) score within 30 days after onset of an attack, and follow-up EDSS 6 months after attack. Adult patients with multiple sclerosis (n = 632) were identified from the Comprehensive Longitudinal Investigations in Multiple Sclerosis at Brigham study (CLIMB), and paediatric patients (n = 132) from the US Network of Paediatric Multiple Sclerosis Centers (NPMSC) registry. Change in EDSS was defined as the difference in EDSS between attack and follow-up. Change in EDSS at follow-up compared to baseline was significantly lower in children compared to adults (P = 0.001), as were several functional system scores. Stratification by decade at onset for change in EDSS versus age found for every 10 years of age, EDSS recovery is reduced by 0.15 points (P < 0.0001). A larger proportion of children versus adults demonstrated improvement in EDSS following an attack (P = 0.006). For every 10 years of age, odds of EDSS not improving increase by 1.33 times (P < 0.0001). Younger age is associated with improved recovery from relapses. Age-related mechanisms may provide novel therapeutic targets for disability accrual in multiple sclerosis.

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