Preparation and activity study of the cholesterol oxidase membrane used in biosensor

INTRODUCTIONCellulose acetate( CA) is a material which was used widely in immobilizing enzyme,commonly,CA membrane was prepared by the means of LB means,nucleus hole,electricity polymerization means,chemical vapor deposition( CVD) and pump,etc.,in these m…     

Space physiology II: adaptation of the central nervous system to space flight—past, current, and future studies

Experiments performed in orbit on the central nervous system have focused on the control of posture, eye movements, spatial orientation, as well as cognitive processes, such as three-dimensional visual perception and mental representation of space. Brain activity has also been recorded during and immediately after space flight for evaluating the changes in brain structure activation during tasks involving perception, attention, memory, decision, and action. Recent ground-based studies brought evidence that the inputs from the neurovestibular system also participate in orthostatic intolerance. It is, therefore, important to revisit the flight data of neuroscience studies in the light of new models of integrative physiology. The outcomes of this exercise will increase our knowledge on the adaptation of body functions to changing gravitational environment, vestibular disorders, aging, and our approach towards more effective countermeasures during human space flight and planetary exploration.     

Reflection of induced and amplified food motivation in impulse activity of the masticatory muscles during electrostimulation of the “hunger center” in the lateral hypothalamus in rabbits

We studied reflection of artificially induced and amplifi ed food motivation in impulse activity of the masticatory muscles during electrostimulation of “hunger center” of the lateral hypothalamus in the absence and presence of food. The threshold stimulation of the lateral hypothalamus in hungry and satiated animals in the absence of food induced incessant food-procuring behavior paralleled by regular generation of spike bursts in masticatory muscles with biomodal distributions of intervals between pulses. This reaction of masticatory muscles during stimulation of the lateral hypothalamus in the absence of food was an example of the anticipatory reaction reflecting characteristics of the action result acceptor. Higher level of hunger motivation during threshold stimulation of the lateral hypothalamus in hungry and satiated rabbits in the course of effective food-procuring behavior increased the incidence of spike burst generation during the food capture phase, but did not modify this parameter during the chewing phase. Impulse activity of the masticatory muscles reflected convergent interactions of food motivation and support excitation on neurons of the central generator of chewing pattern.     

”Rodent-like” and ”primate-like” types of astroglial architecture in the adult cerebral cortex of mammals: a comparative study

Previous observations disclosed that astroglia with interlaminar processes were present in the cerebral cortex of adult New and Old World monkeys, but not in the rat, and scarcely in the prosimian Microcebus murinus. The present report is a more systematic and comprehensive comparative analysis of the occurrence of such processes in the cerebral cortex of several mammalian species. Brain samples were obtained from adult individuals from the following orders: Carnivora (canine), Rodentia (rat and mouse), Marsupialia (Macropus eugenii), Artiodactyl (bovine and ovine), Scandentia (Tupaia glis), Chiroptera (Cynopteris horsfieldii and C. brachyotis), and Primate: Prosimian (Eulemur fulvus), non-human primate species (Cebus apella, Saimiri boliviensis, Callithrix, Macaca mulatta, Papio hamadryas, Macaca fascicularis, Cercopithecus campbelli and C. ascanius) and from a human autopsy. Tissues were processed for immunocytochemistry using several antibodies directed against glial fibrillary acidic protein (GFAP), with or without additional procedures aimed at the retrieval of antigens and enhancement of their immunocytochemical expression. The cerebral cortex of non-primate species had an almost exclusive layout of stellate astrocytes, with only the occasional presence of long GFAP-IR processes in the dog that barely crossed the extent of lamina I, which in this species had comparatively increased thickness. Species of Insectivora and Chiroptera showed presence of astrocytes with long processes limited to the ventral basal cortex. Interlaminar GFAP-IR processes were absent in Eulemur fulvus, at variance with their limited presence and large within- and inter-individual variability as reported previously in Microcebus murinus. In New World monkeys such processes were absent in Callithrix samples, at variance with Cebus apella and Saimirí boliviensis. Overall, the expression of GFAP-IR interlaminar processes followed a progressive pattern: bulk of non-primate species (lack of interlaminar processes) –Chiroptera and Insectivora (processes restricted to allocortex) <strepsirhini <haplorhini (platirrhini<catarrhini). This trend is suggestive of the emergence of new evolutionary traits in the organization of the cerebral cortex, namely, the emergence of GFAP-IR long, interlaminar processes in the primate brain. Interlaminar processes may participate in a spatially restricted astroglial role, as compared to the one provided by the astroglial syncytium. It is proposed that the widely accepted concept of an exclusively astroglial syncytium is probably linked with a specific laboratory animal species (”rodent-type” or, rather, ”general mammalian-type” model) that misrepresents the astroglial architecture present in the cerebral cortex of most anthropoid adult primates (”primate-type” model), including man. Accepted: 28 June 1999     

Transitions in a postural task: do the recruitment and suppression of degrees of freedom stabilize posture?

In this study, we examined flexibility in postural coordination by inducing transitions between postural patterns. Previous work demonstrated that the postural control system produces two task-specific postural patterns as a function of the frequency of support surface translation. For slow translation frequencies (<0.5 Hz), subjects ride on the platform reminiscent of upright stance (ride pattern), and for fast frequencies (≥0.75 Hz) subjects actively fixed the head and trunk in space (head fixed pattern) during anterior-posterior platform motion. To study the adaptation of the postural control system, we had subjects stand on a support surface undergoing increases (from 0.2 to 1.0 Hz in 0.1-Hz steps) and decreases (from 1.0 to 0.2 Hz in 0.1-Hz steps) in translation frequency with the eyes open and closed. Kinematic measures of sagittal plane body motion revealed a gradual transition between these two postural patterns as a function of frequency scaling. In both the increasing and decreasing frequency conditions with visual input, center of mass displacements gradually decreased and increased, respectively, whereas upper-trunk (and head) displacement decreased gradually within the ride pattern until a head fixed pattern was observed without any significant changes in displacement for translation frequencies at and above 0.6 Hz. Without visual input, the scaling of the ride pattern was similar except the transition to the head fixed pattern never emerged with increasing frequency; instead, a less stable pattern exhibiting slow drift in head-trunk anterior-posterior motion (drift pattern) was observed at and above 0.5 Hz oscillations. The stability of the head fixed pattern at fast frequencies was clearly dependent on visual input suggesting that vision was more critical for trunk and head control in space at high than low translation frequencies. Head velocity was kept constant, and lower with vision, as translation frequency (and velocity) changed suggesting a head velocity threshold constraint across postural patterns. The gradual transition from the ride to the head fixed pattern was made possible by the recruitment of available degrees of freedom in the form of ankle, then knee, and then hip joint motion. In turn, the transition from the head fixed or drift pattern was made possible by the gradual suppression of available degrees of freedom in the form of reducing hip, then knee, and then ankle motion. The gradual change in postural kinematics without instabilities and hysteresis suggests that the ability to recruit and suppress biomechanical degrees of freedom allows the postural control system to gradually change postural strategies without suffering a loss of stability. The results are discussed in light of possible self-organizing mechanisms in the multisensory control of posture. Electronic Publication     

Expression of sodium channel α- and β-subunits in the nervous system of themyelin-deficient rat

Summary Using subtype-specific riboprobes and a non-isotopein situ hybridization technique, the pattern of expression of the mRNAs for voltage dependent sodium channel -subunits I, II, III and NaG, and the ₁-subumt were compared inmyelin-deficient rats and unaffected male littermates. Tissues examined included the hippocampus, cerebellum, spinal cord and dorsal root ganglia. Previous studies have demonstrated that the expression of sodium channel - and ₁-subunits follows a distinct temporal and spatial pattern during development, characterized in part by greater expression of -subunit III and its mRNA during development than in the adult. We examined animals of 20–22 days of age, a time when, according to earlier reports, the unaffected animals should nearly have reached an adult expression pattern. Normal male littermates were indeed found to express a sodium channel subunit mRNA pattern generally consistent with previous reports on adult rats.Myelin-deficient animals exhibited an expression pattern identical to the unaffected littermates, indicating that myelination is not required for the progression from the embryonic to the adult expression pattern of sodium channel subunits.     

Reflex regulation of the “spontaneous” activity of the chemoreceptors of the tongue

Summary The spontaneous activity of the chemoreceptors of the frog's tongue was studied during stimulation of the interoceptors of the stomach and of the sympathetic chain. It was found to be under the control of the nervous system, adapting the receptors to give improved perception, and it indicates the preparedness of these apparatuses to receive stimuli. Spontaneous activity may be fundamentally a partial principle of the functioning of receptor elements. Further electrophysiological investigations of this problem are proceeding.(Presented by Active Member AMN SSSR P. K. Anokhin) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 55, No. 8, pp. 7–11, August, 1963     

The features of the influence of “reward areas” on the electrical activity of the parafascicular complex of nuclei in the developing rabbit

The influence of the electrostimulation of reward areas, preliminarily identified by the self-stimulation technique, on the evoked potentials recorded in the parafascicular complex of the thalamus in response to peripheral nociceptive stimulation was studied in 35 rabbits, of 41–60 days of life. When comparison was made of the data obtained with the results of studies carried out previously in adult animals and in rabbits from the 30th–40th days, in addition to common characteristics, features of these influences which were characteristics only for the age interval under investigation were distinguished. The antinociceptive influences of the reward areas on the evoked potentials in the parafascicular complex were less pronounced with respect to a number of parameters in the period of the rabbits life occupying the intermediate position between the over-excitable and adult periods of development.Translated from Fiziologicheskii Zhurnal, Vol. 77, No. 8, pp. 76–83, August, 1991.     

Impact of sympathetic nervous system activity on post‐exercise flow‐mediated dilatation in humans

AbstractTransient reduction in vascular function following systemic large muscle group exercise has previously been reported in humans. The mechanisms responsible are currently unknown. We hypothesised that sympathetic nervous system activation, induced by cycle ergometer exercise, would contribute to post‐exercise reductions in flow‐mediated dilatation (FMD). Ten healthy male subjects (28 ± 5 years) undertook two 30 min sessions of cycle exercise at 75% HR_max. Prior to exercise, individuals ingested either a placebo or an α₁‐adrenoreceptor blocker (prazosin; 0.05 mg kg⁻¹). Central haemodynamics, brachial artery shear rate (SR) and blood flow profiles were assessed throughout each exercise bout and in response to brachial artery FMD, measured prior to, immediately after and 60 min after exercise. Cycle exercise increased both mean and antegrade SR (P < 0.001) with retrograde SR also elevated under both conditions (P < 0.001). Pre‐exercise FMD was similar on both occasions, and was significantly reduced (27%) immediately following exercise in the placebo condition (t‐test, P = 0.03). In contrast, FMD increased (37%) immediately following exercise in the prazosin condition (t‐test, P = 0.004, interaction effect P = 0.01). Post‐exercise FMD remained different between conditions after correction for baseline diameters preceding cuff deflation and also post‐deflation SR. No differences in FMD or other variables were evident 60 min following recovery. Our results indicate that sympathetic vasoconstriction competes with endothelium‐dependent dilator activity to determine post‐exercise arterial function. These findings have implications for understanding the chronic impacts of interventions, such as exercise training, which affect both sympathetic activity and arterial shear stress.

Abbreviations

BF

blood flow

CO

cardiac output

FMD

flow‐mediated dilatation

HR

heart rate

LBNP

lower body negative pressure

MAP

mean arterial pressure

MSNA

muscle sympathetic nerve activity

SNS

sympathetic nervous system

SR

shear rate

SR_AUC

shear rate area under curve

SV

stroke volume

TPRi

total peripheral resistance index

     

Primary immunodeficiencies in Central and Eastern Europe—the power of networking Report on the activity of the Jeffrey Modell Foundation Centers Network in Central and Eastern Europe

Jeffrey Modell Foundation centers’ network activities in Central and Eastern Europe (JMF CEE) have contributed to the development of care for patients with primary immunodeficiencies. On the data continuously collected from individual centers in participating countries since 2011, we demonstrate a steady improvement in a number of aspects concerning complex care for patients with primary immunodeficiencies. The presented data show an improvement of awareness about these rare diseases across the whole Central and Eastern European region, an increase in newly diagnosed patients as well as genetically confirmed cases, earlier establishment of diagnosis, and improved access to clinical treatment. We also present an active patient involvement that is reflected in the expansion of patient organization centers and their activities. The cooperation within the JMF CEE network has also contributed to greater international exposure of participating centers and further to the gradual development of research activities in the rapidly evolving field of primary immunodeficiencies. The improvement of all important aspects of the complex field of primary immunodeficiencies within the JMF CEE network documents the strength and advantages of the joint and coordinated networking.

     

Are mechanically sensitive regulators involved in the function and (patho)physiology of cerebral palsy-related contractures?

Skeletal muscle tissue is mechanosensitive, as it is able to sense mechanical impacts and to translate these into biochemical signals making the tissue adapt. Among its mechanosensitive nature, skeletal muscle tissue is the largest metabolic organ of the human body. Disturbances in skeletal muscle mechanosensing and metabolism cause and contribute to many diseases, i.e. muscular dystrophies/myopathies, cardiovascular diseases, COPD or diabetes mellitus type 2. A less commonly focused muscle-related disorder is clinically known as muscle contractures that derive from cerebral palsy (CP) conditions in young and adults. Muscle contractures are characterized by gradually increasing passive muscle stiffness resulting in complete fixation of joints. Different mechanisms have been identified in CP-related contractures, i.e. altered calcium handling, altered metabolism or altered titin regulation. The muscle-related extracellular matrix (ECM), specifically collagens, plays a role in CP-related contractures. Herein, we focus on mechanically sensitive complexes, known as costameres (Cstms), and discuss their potential role in CP-related contractures. We extend our discussion to the ECM due to the limited knowledge of its role in CP-related contractures. The aims of this review are (1) to summarize CP-related contracture mechanisms, (2) to raise novel hypotheses on the genesis of contractures with a focus on Cstms, and (3) to stimulate novel approaches to study CP-related contractures.     

Effect of deoxycorticosterone on 5′-nucleotidase and adenosine deaminase activity in the rat hypothalamus and hippocampus

Laboratory of Neurochemistry, Kiev Research Institute of Endocrinology and Metabolism, Ministry of Health of the Ukrainian SSR. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 110, No. 7, pp. 56–58, July, 1990.