Correlations between redox-state potential changes in different tissues and the heart frequency in vivo

Redosis evoked in different tissues by methylene-blue or menadione (oxidants), resulted in an increase in heart frequency, while oxidosis evoked by thiamine or cysteine (reductants) diminished the frequency. In isolated organ tissues where compensatory redox feed back overshoots are rarely to develop, owing to the low redox buffer capacity and lack of the influence of nervous and humoral factors, the heart frequency decreased in response to direct oxidosis induced by the application of oxidants, and increased following reductant application; this suggested an environmental type redox regulatory influence of the agents rather than specific action of the agents. This environmental type effect can result from direct action on isolated organs, or from direct and indirect actions in vivo. An increased redox-state potential resulted in decreased heart frequency and inversely. In a pathological situation provoked by complete strangulation of aortae, a significant oxidosis developed in parallel with a decrease in heart frequency. On increasing the redox buffer capacity by application of methylene-blue (oxidant), or thiamine (reductant) both the redox and the resulting heart frequency changes could readily be counteracted. When cigarette smoke was pumped through an intratracheal tube, a significant redosis developed in the heart ventricle in parallel with an increased heart frequency. These data show that regardless of the origin of redox-state potential changes in tissues, a shift to oxidosis decreases and a shift to redosis increases the heart frequency.     

Analysis of the influence of aeroions on ECG and correlation between this action and tissue redox-state potential

It was observed in rats, that following negative aeroionization heart frequency and the altitude of P-waves increased. After positive ionization these interrelationships took place inversely. As between these effects and the tendency of tissue redox-state potential changes correlation was seen, the results were grouped also on redox basis, independently on whether the increase or decrease of redox-state potential was caused by negative or positive aeroions. The results of this grouping showed, that following an elevation of tissue redox-state potential (+delta E'0) heart frequency dropped, and the altitude of T-waves increased. After a decrease of tissue redox-state potential (-delta E'0) these interrelationships were realized inversely. After -delta E'0 the positive chronotropic influence of noradrenaline increased, but consequent to +delta E'0 the classical positive chronotropic effect of this catecholamine was reversed. These results corroborate our earlier notion, that aeroions exert their action on heart through changing tissue redox-state potential.     

Correlations between the tissue redox-state and K(+)-contractures

Analyzing the mechanisms of redox-modulation of the excitatory-contractory process, recently the amplitude of K(+)-contractures, tissue redox-state potential and electrical burst activity were simultaneously measured in the rectus abdominis muscle of the frog (Rana esculenta) following oxidant (thionine) and reductant (ascorbate) treatments. Pretreatment with oxidant in parallel with the increment of redox-state potential increased, while pretreatment with reductant, parallel with the decrement of redox-state potential decreased significantly both the amplitudes of K(+)-contractures and the electrical burst activity. The main mechanisms of action of this phenomenon, at least of the phasic portion, in all probability is the increase of intracellular quotient of the ionized/bound calcium after oxidizing, but a decrease of this quotient following reducing shifts. In the case of tonic portion an increase of Ca2(+)-influx through the Na(+)-Ca2(+)-exchange diffusion mechanisms seems feasible. Other mechanisms are also discussed. Hence, the mechanism of K(+)-contractures is under the control of tissue redox-state potential as well.     

Correlations between the actual redox-state potential (E0') of biophase and heart activity in vivo

In CFY rats the tissue redox-state potential (E0') in heart, m. vastus medialis and in the liver, and the heart frequency and QRS amplitudes were measured parallel. It was observed that following compensatory redosis caused by konakion both the autorhythmic heart frequency and QRS amplitudes increased, while after compensatory oxidosis induced by urea occurred the opposite. Following compensatory redosis caused by konakion acetylcholine decreased, but adrenaline increased the heart frequency and QRS amplitudes more intensively than at normal E0' values. After compensatory oxidosis caused by urea, acetylcholine decreased the heart frequency and QRS amplitudes significantly less. Adrenaline decreased the heart frequency in such milieu. On the basis of these data the following conclusions are proposed; For the realization of autorhythmic activity, for negative type acetylcholine and for positive type adrenaline effects in heart, a relatively low primordial tissue E0' value is an essential back-ground element. Among the mechanisms controlling autorhythmicity and sympathetic/parasympathetic effects the actual and permanently changing tissue E0' value is also an important modifying, or through biochemical redox feed-back mechanisms even a regulatory factor of heart activity.     

Correlations between adrenal weight and heart weight in rats with a cardiac overload

A significant positive correlation between heart weight and adrenal weight was found in rats with myocardial hypertrophy induced by experimental hyperthyroidism or ligation of the abdominal aorta. The simultaneous administration of digitoxin partly inhibited myocardial hypertrophy after ligation of the abdominal aorta, but not after experimental hyperthyroidism. Digitoxin also inhibited adrenal hypertrophy after ligature of the abdominal aorta but, again, not after experimental hyperthyroidism. The possible existence of an endogenous cardiotropic hormone participating in the development of cardiac hypertrophy from overloading is discussed.     

Correlations between blood and tissue omega-3 LCPUFA status following dietary ALA intervention in rats

The aim of this study was to assess relationships between the fatty acid contents of plasma and erythrocyte phospholipids and those in liver, heart, brain, kidney and quadriceps muscle in rats. To obtain a wide range of tissue omega-3 (n-3) long chain polyunsaturated fatty acids (LCPUFA) we subjected weanling rats to dietary treatment with the n-3 LCPUFA precursor, alpha linolenic acid (ALA, 18:3 n-3) for 3 weeks. With the exception of the brain, we found strong and consistent correlations between the total n-3 LCPUFA fatty acid content of both plasma and erythrocyte phospholipids with fatty acid levels in all tissues. The relationships between eicosapentaenoic acid (EPA, 20:5 n-3) and docosapentaenoic acid (DPA, 22:5 n-3) content in both blood fractions with levels in liver, kidney, heart and quadriceps muscle phospholipids were stronger than those for docosahexaenoic acid (DHA, 22:6 n-3). The strong correlations between the EPA+DHA (the Omega-3 Index), total n-3 LCPUFA and total n-3 PUFA contents in both plasma and erythrocyte phospholipids and tissues investigated in this study suggest that, under a wide range of n-3 LCPUFA values, plasma and erythrocyte n-3 fatty acid content reflect not only dietary PUFA intakes but also accumulation of endogenously synthesised n-3 LCPUFA, and thus can be used as a reliable surrogate for assessing n-3 status in key peripheral tissues.     

Treadmill running produces both positive and negative physiological adaptations in Sprague-Dawley rats

Exercise training produces a vast array of physiological adaptations, ranging from changes in metabolism to muscle mitochondrial biogenesis. Researchers studying the physiological effects of exercise often use animal models that employ forced exercise regimens that include aversive motivation, which could activate the stress response. This study examined the effect of forced treadmill running (8 wk) on several physiological systems that are sensitive to training and stress. Forced treadmill running produced both positive and negative physiological adaptations. Indicative of positive training adaptations, exercised male Sprague-Dawley rats had a decrease in body weight gain and an increase in muscle citrate synthase activity compared with sedentary controls. In contrast, treadmill running also resulted in the potentially negative adaptations of adrenal hypertrophy, thymic involution, decreased serum corticosteroid binding globulin, elevated lymphocyte nitrite concentrations, suppressed lymphocyte proliferation, and suppressed antigen-specific IgM. Such alterations in neuroendocrine tissues and immune responses are commonly associated with chronic stress. Thus treadmill running produces both positive training adaptations and potentially negative adaptations that are indicative of chronic stress. Researchers employing forced activity need to be aware that this type of exercise procedure also produces physiological adaptations indicative of chronic stress and that these changes could potentially impact other measures of interest.     

Interactions between two closely related phytal harpacticoid copepods, asymmetric positive and negative effects

Competition for food is generally thought to exert a strong evolutionary pressure, driving trophic niche separation, either by specialization and/or by widening the choice of potential food resources. Harpacticoid copepods are common inhabitants of phytal assemblages, where several closely related species of the so-called phytal dwelling families often co-occur. However, direct competition among phytal harpacticoids has been thought to be unlikely, due to the abundant and continuously available food supplies. We conducted a series of field and laboratory studies to assess the role of competition in the abundance distribution of two closely related harpacticoid species, Mesochra rapiens and M. aestuari. We found that the abundance of both species co-varied on several seaweed species in the northern Baltic Sea, during a 3-month period. Stable isotope ratios in the green alga Cladophora glomerata field samples indicated different resource utilization of the two species, both in fresh and deteriorated C. glomerata, and in drifting algae. We tested in the laboratory if resource utilization was different between the species in sympatry and allopatry. We used enriched stable carbon isotope ratios (¹³C/¹²C) of the diatom Phaeodactylum tricornutum to trace the uptake in both species. Results from these experiments showed a much higher assimilation by M. aestuari in sympatry with M. rapiens, while the latter species showed a higher assimilation in allopatry. Our results show that while there is no apparent competition for resources between these two species in the field, there seems to be an asymmetric reaction when in sympatry and provided one single resource in the laboratory. We suggest that M. rapiens may facilitate assimilation by M. aestuari and discuss the mechanisms by which this may take place.     

Correlations between indices of P300 EEG potential,cognitive tests,and variational pulsometry in Parkinsonian patients

The parameters of an event-related EEG potential (ERP), P300 wave, are now extensively used as objective neurophysiological indices of the state of cognitive functions. At the same time, information on the effects of the autonomic nervous system on the parameters of P300 is limited. In Parkinson’s disease clinics, in addition to the leading motor disorders, more or less clear psychoemotional, cognitive, and autonomic (in particular cardiovascular) impairments are usually observed. This allows one to study the dependence between the cardiovascular dysfunction and intensity of cognitive disorders in Parkinsonian patients. In our study on this contingent, we analyzed correlations between the parameters of P300 potential, indices of the state of the cognitive sphere (determined using a questionnaire, Mini Mental State Examination, MMSE, and a Luriya’s test), and indices of variational pulsometry. Thirty-five Parkinsonian patients (49 to 74 years, severity of disease 1.5 to 3.0 by the international classification) were examined. We found a negative influence of excessive sympathetic tonus in cardiovascular control on the state of cognitive functions. The latency of P300 potential was longer in patients with greater intensities of sympathetic influences on the cardiovascular system. The coefficients of correlation of the latency of P300 with the amplitude of mode of R-R intervals (AMo), index of tension in the regulatory systems by Baevskii (IT), and index of autonomic balance by Baevskii (IAB) were 0.52 (P < 0.01), 0.36 (P < 0.05), and 0.37 (P < 0.05), respectively. The above autonomic indices demonstrated significant negative correlations with the volume of short-term memory measured by Luriya’s test. The P300 latency, in turn, showed negative correlations with the memory volume estimated by the MMSE scale and Luriya’s test. With increase in the age of patients, the degree of the above-mentioned correlations between the P300 latency, memory volume (by Luriya’s test), and parameters of variational pulsometry increased. Our data emphasize the expedience of “routine” studies of the balance of sympathetic and parasympathetic control in pathological states accompanied by clear or subclinical cognitive disorders. Early recognition of cardiovascular dysfunction and its corresponding therapeutic correction should improve the state of brain functions and quality of life in patients suffering from neurodegenerative diseases, in particular from Parkinson’s disease. Neirofiziologiya/Neurophysiology, Vol. 40, No. 1, pp. 43–52, January–February, 2008.     

大兴安岭湿地潜在分布与环境因子的相关性

为了研究大兴安岭湿地在现行气候下的潜在分布,以大兴安岭地区的沼泽、沼泽化草甸、草甸为研究对象,选择对湿地可能有影响的地貌因子(海拔、坡度、坡位、综合地形指数、照射坡向)、水文因子(到河流的距离、到湖泊的距离)和气候因子(年平均温度、年降水量),利用SPSS软件建立Logistic逐步回归模型,探讨沼泽、沼泽化草甸、草甸分布与9种环境因子的相关关系。结果表明:模型模拟的湿地分布在大兴安岭北部和南部都具有较高可信度,其相对特征曲线值(ROC)分别为71.70%和73.40%;同时,模型模拟的沼泽化草甸、草甸在大兴安岭南部的分布也都具有较高的可信度;但在大兴安岭北部,沼泽、沼泽化草甸、草甸的Logistic回归模型的相对特征曲线值则不高。由于其分布形式趋于随机,模型模拟结果也是可信的。相关性分析表明,在区域尺度上,大兴安岭南部的草甸分布对温度最敏感;北部的草甸分布及其它类型湿地的分布均对地形因子最敏感。     

Correlations between amino acid concentrations in brains of seizure-susceptible and seizure-resistant rats

We have examined the relationship between free amino acid concentrations in the brains of genetically seizure-susceptible and seizure-resistant rats. The concentrations of free amino acids in the two strains do not differ significantly in the inferior colliculus or the cortex. However, animal-to-animal variations in the concentrations of numerous amino acid pairs are highly correlated. Glutamic acid decarboxylase activities did not vary between the two strains.We conclude that the strong correlations reported between glutamate and taurine levels in several species are not unique to this amino acid pair. Furthermore, unlike the situation with some experimentally-induced epilepsies, genetic epilepsy is not associated with major disturbances in free amino acid concentrations. The high correlations between amino acid pairs in some cases may reflect variations in cellular and subcellular compartment sizes that are shared by several amino acids.     

Interactions between adult and larval bluegill sunfish: positive and negative effects

Adult fish may affect the growth and survival of conspecific larvae through a variety of pathways, including negative interactions via competition for shared limiting resources or via predation (i.e., cannibalism), and positive interactions due to the consumption of larval predators and via resource enhancement (i.e., presence of adults increases availability of larval prey). To examine the overall effect of adult bluegill sunfish (Lepomis macrochirus) on larval bluegill, we conducted a field experiment in which we manipulated adult densities and quantified larval growth and survival, prey abundance, invertebrate predator abundance, and cannibalism. The presence of adult bluegill had a negative effect on final larval mass. This response was consistent with competition for zooplankton prey. Adult bluegill reduced the abundance of large zooplankton (e.g., Chaoborus and Daphnia), which were the dominant prey of bluegill larvae in the absence of adults. Larvae in the no-adult treatment also had significantly more prey in their stomachs compared to larvae in the presence of adults. Larval survival was maximized at intermediate adult densities and the overall production of larvae peaked at intermediate adult densities. The higher larval survival at intermediate adult densities is attributed to a reduction in invertebrate predators in treatments with adult bluegill; invertebrate predators experienced an 80% reduction in the presence of adult fish. Decreased larval survival at the highest adult density was not due to resource limitation and may be due to cannibalism, which was not directly observed in our study, but has been observed in other studies.     

Conditions for positive and negative correlations between fitness and heterozygosity in equilibrium populations.

The past decades have witnessed extensive efforts to correlate fitness traits with genomic heterozygosity. While positive correlations are revealed in most of the organisms studied, results of no/negative correlations are not uncommon. There has been little effort to reveal the genetic causes of these negative correlations. The positive correlations are regarded either as evidence for functional overdominance in large, randomly mating populations at equilibrium, or the results of populations at disequilibrium under dominance. More often, the positive correlations are viewed as a phenomenon of heterosis, so that it cannot possibly occur under within-locus additive allelic effects. Here we give exact genetic conditions that give rise to positive and negative correlations in populations at Hardy-Weinberg and linkage equilibria, thus offering a genetic explanation for the observed negative correlations. Our results demonstrate that the above interpretations concerning the positive correlations are not complete or even necessary. Such a positive correlation can result under dominance and potentially under additivity, even in populations where associated overdominance due to linked alleles at different loci is not significant. Additionally, negative correlations and heterosis can co-occur in a single population. Although our emphasis is on equilibrium populations and for biallelic genetic systems, the basic conclusions are generalized to non-equilibrium populations and for multi-allelic situations.     

A positive/negative ion-switching, targeted mass spectrometry-based metabolomics platform for bodily fluids, cells, and fresh and fixed tissue

The revival of interest in cancer cell metabolism in recent years has prompted the need for quantitative analytical platforms for studying metabolites from in vivo sources. We implemented a quantitative polar metabolomics profiling platform using selected reaction monitoring with a 5500 QTRAP hybrid triple quadrupole mass spectrometer that covers all major metabolic pathways. The platform uses hydrophilic interaction liquid chromatography with positive/negative ion switching to analyze 258 metabolites (289 Q1/Q3 transitions) from a single 15-min liquid chromatography-mass spectrometry acquisition with a 3-ms dwell time and a 1.55-s duty cycle time. Previous platforms use more than one experiment to profile this number of metabolites from different ionization modes. The platform is compatible with polar metabolites from any biological source, including fresh tissues, cancer cells, bodily fluids and formalin-fixed paraffin-embedded tumor tissue. Relative quantification can be achieved without using internal standards, and integrated peak areas based on total ion current can be used for statistical analyses and pathway analyses across biological sample conditions. The procedure takes ～12 h from metabolite extraction to peak integration for a data set containing 15 total samples (～6 h for a single sample).     

Correlations between local strains and tissue phenotypes in an experimental model of skeletal healing

Defining how mechanical cues regulate tissue differentiation during skeletal healing can benefit treatment of orthopaedic injuries and may also provide insight into the influence of the mechanical environment on skeletal development. Different global (i.e., organ-level) mechanical loads applied to bone fractures or osteotomies are known to result in different healing outcomes. However, the local stimuli that promote formation of different skeletal tissues have yet to be established. Finite element analyses can estimate local stresses and strains but require many assumptions regarding tissue material properties and boundary conditions. This study used an experimental approach to investigate relationships between the strains experienced by tissues in a mechanically stimulated osteotomy gap and the patterns of tissue differentiation that occur during healing. Strains induced by the applied, global mechanical loads were quantified on the mid-sagittal plane of the callus using digital image correlation. Strain fields were then compared to the distribution of tissue phenotypes, as quantified by histomorphometry, using logistic regression. Significant and consistent associations were found between the strains experienced by a region of the callus and the tissue type present in that region. Specifically, the probability of encountering cartilage increased, and that of encountering woven bone decreased, with increasing octahedral shear strain and, to a lesser extent, maximum principal strain. Volumetric strain was the least consistent predictor of tissue type, although towards the end of the four-week stimulation timecourse, cartilage was associated with increasingly negative volumetric strains. These results indicate that shear strain may be an important regulator of tissue fate during skeletal healing.     

The complex interplay between mosquito positive and negative regulators of Plasmodium development

The malaria parasite, Plasmodium, requires sexual development in the mosquito before it can be transmitted to the vertebrate host. Mosquito genes are able to substantially modulate this process, which can result in major decreases in parasite numbers. Even in susceptible mosquitoes, haemolymph proteins implicated in systemic immune reactions, together with local epithelial responses, cause lysis of more than 80% of the ookinetes that cross the mosquito midgut. In a refractory mosquito strain, immune responses lead to melanisation of virtually all parasites. Conversely, certain mosquito genes have an opposite effect: they are used by the parasite to evade defence reactions. Detailed understanding of the interplay between positive and negative regulators of parasite development could lead to the generation of novel approaches for malaria control through the vector.