Rearrangement of Spectrum of Digestive Proteases in Postnatal Ontogenesis of Rats

At simultaneous determination of activities of gastric, pancreatic, and enteric proteolytic enzymes, a strict adaptability has been shown of spectrum of the enzymes of luminal and membrane hydrolysis of proteins to the use of immunoglobulins from mother's milk at the period of breast-feeding. It is seen in that activities of gastric pepsin and the complex of pancreatic proteases is extremely low at this period of development, and the enteric dipeptide hydrolase is located in the distal part of the small intestine. Stress factors change all these characteristics and shift them from the juvenile state to the definitive one to become thereby a powerful cause of increase of risk of various gastrointestinal diseases.     

Neuronal Organization of Mammalian Stellate Ganglion in Postnatal Ontogenesis

The paper considers the problem of peculiarities of maturation of the stellate ganglion nerve elements in mammals of different species. This process differs in precocious and altricial animals. It has been shown that in spite of some individual peculiarities, the neurons, fibers, and conducting pathways in altricial animals are not, on the whole, completely formed morphologically and functionally. In the course of postnatal ontogenesis, not only an increase of cell sizes and development of dendrite tree, but also reorganization of nerve connections with target organ occur. The postnatal ontogenesis is also accompanied by an increase of the excitation transmission rate along the fibers and by their myelination. The asymmetry of the right and left stellate ganglia (SG) by their sizes and functional peculiarities, which exists in adult animals appears as soon as at early stages of postnatal development. The neural elements of precocious animals are changed to a lesser extent in postnatal ontogenesis and are, in many aspects, similar to those of adult organisms as early as at birth.     

An Ultrastructural Study of Cell-to-Cell Membrane Interaction at Early Stages of Postnatal Ontogenesis of Cortical Brain Neurons in White Rats

In early postnatal ontogenesis of cerebral cortex (visual area) of the white rat, a wide distribution of different types of membrane contacts have been found between developing nervous cells and their processes. The following types of contacts were observed: 1. Penetration of thin filopodia into specialized invaginations having all the features of coated vesicles; 2. Contacts of filopodia with thickened surface membrane; 3. Contacts of opposit filopodia; 4. Contacts of membranes with reciprocal invaginations alternating with filopodia or surface blebs.
These types of membrane interaction were regularly distributed along the surface of cells and their processes, and were situated in close approximation to typical tight junctions and other adhesional complexes. As a rule, filopodia were components of axon branches, and almost all invaginations were situated on plasma membranes of cell bodies or on dendrites, although sometimes there were invaginations on axon profiles and filopodia on dendrites.
It is suggested that the distribution and structural specialization of these membrane contacts reflect their participation in the process of programmed cell-to-cell recognition that precedes the formation of synaptic contact. Other reports and the current data reveal the special morphogenetic role of membrane communication in the formation and stability of integrative cell systems.     

Secondary Rhythms of Cardiac Activity within Early Ontogenesis: Effects of Blocking of Adreno- and Cholinoreceptors in Rats

The genesis of secondary rhythms in autorhythmic functional systems is analyzed on the example of the spectra of fluctuations of the heart rate observed within early postnatal ontogenesis of rats (from the moment of birth until three weeks old). We studied the effects of blocking of -adrenoreceptors with phentolamine (5 mg/kg, i.p.), of -adrenoreceptors with propranolol (1 mg/kg), and of M cholinoreceptors with atropine (1 mg/kg). We concluded that sympathetic influences stabilize the cardiac rhythm in newborn animals, but from the second postnatal week the effects determining generation of secondary rhythms of cardiac activity begin to be mediated by these receptors. Parasympathetic effects on secondary cardiorhythms mediated by M cholinoreceptors are effective even in newborn rats. In rats older than 7 to 8 days, blocking of -adrenoreceptors and M cholinoreceptors led to the same result, synchronization of the secondary cardiac rhythms. Disorders in the afferent link of the baroreflex arcs after the blockade of -adrenoreceptors and cessation of transmission in the efferent link of these arcs after blockade of M cholinoreceptors are considered a probable reason for this phenomenon.     

Estimates of the Parameters of Respiratory Sinus Arrhythmia

Human Physiology - This article shows that significant numerical differences in the estimates of respiratory sinus arrhythmia (RSA) parameters by the spectral method and the RMSSD index (standard...     

Synchronization of Endogenous Somato- and Visceromotor Activities in Rats in Ontogenesis

It is shown in the experiments on rat pups at the age from neonatal to the end of the 3rd week that bursts of spontaneous somatosensory excitation characteristic of altricial animals at the early postnatal ontogenesis have a pronounced tendency for synchronization with oscillations of the electrical activity level in the antral part of the gastric wall and duodenum. These oscillations represent the so-called secondary rhythms that superpose basic rhythms and are responsible for intersystem interactions. Since the 2nd week after birth the synchronization level decreases essentially. Vagotomy performed at this period increases again the synchronization, which suggests the desynchronizing role of parasympathetic innervation in the process of development.     

Stress-Reactivity of Lungs according to Metabolic Function Parameters at Different Stages of Postnatal Ontogenesis

Analysis of parameters of metabolic function of lungs with respect to lipid metabolism was performed in rats under conditions of acute experimental emotional-nociceptive stress. Study of the stress-sensitivity of lungs in the comparative-age aspect has shown different extent of changes of several parameters of lipid metabolism in pulmonary tissue in animals of different age. The results of the study demonstrate areactivity and high stress-stability of lungs with respect to surface-active properties, free-radical processes, and lipase activity in early postnatal ontogenesis.     

A Minimal Model for the Respiratory Sinus Arrhythmia

The cardiac and respiratory rhythms in humans are known to be coupled by several mechanisms. In particular, the first rhythm is deeply modulated by the second. In this report we propose a simple operational model for heart rate variability which, taking such modulation into account, reproduces the main features of some experimental sequences of RR intervals recorded from healthy subjects in the resting condition. Also, peer analysis of the model performance allows us to answer the question whether the observed behaviour should be ascribed to phase synchronisation of the heart beating to the respiratory rhythm. Lastly, the changes of the model activity brought about by changing its relevant parameters are analysed and discussed     

Tuberous Sclerosis and Cardiac Arrhythmia in Three Zulu Patients

Cardiac arrhythmias, in the form of multiple atrial or ventricular extrasystoles together with various types of conduction defect, occurred in three Zulu patients with tuberous sclerosis. Probably this association occurs more often than has been suspected.     

A Powerful Algorithm to aid Cardiac Arrhythmia Diagnosis

Abstract

The Electrocardiogram (ECG), represents the electrical activity of the heart. It is characterised by a number of waves P, QRS, T which are correlated to the status of the heart activity. In this paper, the aim is to present a powerful algorithm to aid cardiac diagnosis. The approach used is based on a determinist method, that of the tree decision. However, the different waves of the ECG signal need to be identified and then measured following a signal to noise enhancement. Signal to noise enhancement is performed by a combiner linear adaptive filter whereas P, QRS, T wave identification and measurement are performed by a derivative approach. Results obtained on simulated and real ECG signals are shown to be highly, satisfactory in the aid of cardiac arrhythmia diagnosis, such as junctionnal escapes, blocks, etc.     

A Powerful Algorithm to aid Cardiac Arrhythmia Diagnosis

The Electrocardiogram (ECG), represents the electrical activity of the heart. It is characterised by a number of waves P, QRS, T which are correlated to the status of the heart activity. In this paper, the aim is to present a powerful algorithm to aid cardiac diagnosis. The approach used is based on a determinist method, that of the tree decision. However, the different waves of the ECG signal need to be identified and then measured following a signal to noise enhancement. Signal to noise enhancement is performed by a combiner linear adaptive filter whereas P, QRS, T wave identification and measurement are performed by a derivative approach. Results obtained on simulated and real ECG signals are shown to be highly, satisfactory in the aid of cardiac arrhythmia diagnosis, such as junctionnal escapes, blocks, etc.     

一种大鼠心律失常模型的建立

目的建立一种新的心律失常动物模型.方法选用SD大鼠,经股静脉快速给予附子脂溶性生物碱0.425 mg·kg-1,用四道生理记录仪持续记录心电图.结果附子脂溶性生物碱能够引起SD大鼠出现室性早搏、二联律或三联律、短时阵发性室性心动过速、连续性室性心动过速,继而以相反顺序逐渐恢复.用利多卡因反证治疗,与生理盐水相比差异极显著(P<0.001).结论附子脂溶性生物碱注射致大鼠心律失常动物模型是一种可行的方法.     

Development of Lateralization of Unconditional Motor Reactions in Early Ontogenesis of White Rats

The problem of development of lateralization of motor systems in the course of early ontogenesis is important for understanding regularities of formation of functional characteristics of motor control. To solve these tasks, in the 8–74-day old rat pups the presence of lateralization was studied in two motor tests: the choice of the preferable rotation direction at holding the rat by the tail and the choice of one of the forelimbs in the test of initiation of the limb placement onto a support. It has been shown that in early ontogenesis, until the age of the sexual maturation, no constant lateralization is observed in realization of the unconditional motor reactions in any of the performed tests. The turning point of the establishment of the lateral preference has been revealed to correspond to the three-week age (the 21–23rd days), while the final lateralization both for individual animals and for the entire sample takes place at the age of 1.5–2 months. It is suggested that development of lateralization of the limb placement on a support occurs with the approximately two-week delay as compared with the process of formation of the preference in the choice of the rotation direction.     

Biofeedback Assisted Control of Respiratory Sinus Arrhythmia as a Biobehavioral Intervention for Depressive Symptoms in Patients After Cardiac Surgery: A Preliminary Study

The current study investigated whether biofeedback training aimed at increasing respiratory sinus arrhythmia (RSA), a measure of cardiac vagal modulation, can reduce depressive symptoms in patients after cardiac surgery. This randomized controlled study enrolled 26 patients after first-time cardiac surgery. The patients were randomly assigned to an RSA-biofeedback group (N = 13) or to a treatment as usual group (N = 13). The biofeedback training consisted of five 45 min sessions designed to increase RSA. The outcome was assessed as changes in RSA and in the Centre for Epidemiologic Studies of Depression (CES-D) values from pre- to post-training. Both groups were comparable for demographic and biomedical characteristics. RSA increased significantly in patients who underwent RSA-biofeedback compared to controls. Moreover, the CES-D scores were reduced significantly from pre- to post-training in the RSA-biofeedback group compared to the controls. Changes in RSA were inversely related to changes in CES-D scores from pre- to post-training. These findings extend the effectiveness of RSA-biofeedback for increasing vagal modulation as well as for reducing depressive symptoms in post-surgical patients. Overall, the current study also suggests that this biobehavioral intervention may add to the efficacy of postoperative risk reduction programs and rehabilitation protocols in cardiac surgery patients.     

α2B-Adrenoceptor Deficiency Leads to Postnatal Respiratory Failure in Mice

α₂-Adrenoceptors belong to the family of adrenergic receptors, which regulate the neuronal release of norepinephrine as part of a negative feedback loop. Among the α₂-adrenoceptors, the α_2B-subtype may also influence developmental signaling pathways involved in angiogenesis of the placenta. Thus, the aim of the present study was to determine whether α_2B-adrenoceptors are also involved in other developmental processes beyond placental angiogenesis. Ablation of α_2B-adrenoceptors led to lethality of mutant mice during the first hours after birth. Despite normal breathing and drinking behavior, mutant mice developed cyanosis, which could be traced back to a defect in lung morphology with significantly reduced alveolar volume and thickened interalveolar septi. In α_2B-deficient lungs and in isolated alveolar type II cells, expression of sonic hedgehog (SHH) was significantly increased, resulting in mesenchymal proliferation. In vitro α_2B-adrenoreceptor stimulation suppressed expression of sonic hedgehog and the cell cycle genes cyclin D1 and Ki67. In vivo inhibition of enhanced SHH signaling by the smoothened antagonist cyclopamine partially rescued perinatal lethality, lung morphology, and altered gene expression in mutant mice. Thus, α_2B-adrenoceptors in lung epithelia play an important role in suppressing sonic hedgehog-mediated proliferation of mesenchymal cells and thus prevent respiratory failure.