CELL CHANGES IN THE CENTRAL NERVOUS SYSTEM UNDER VARIOUS NATURAL AND EXPERIMENTAL CONDITIONS. THIRD PAPER: FUNCTIONAL ACTIVITY

1927 ◽  
Vol 17 (1) ◽  
pp. 107-117 ◽  
Author(s):  
Joseph A. Dye
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Functional Activity ◽  
Experimental Conditions ◽  
The Central Nervous System ◽  
Cell Changes

scholarly journals The life history of Hepatozoon leptodactyli (Lesage, 1908) Pessoa, 1970: a parasite of the common laboratory animal: the frog of the genus Leptodactylus

1973 ◽  
Vol 71 (1-2) ◽  
pp. 1-8 ◽  
Author(s):  
Sylvio Celso Goncalves da Costa ◽  
Samuel B. Pessoa ◽  
Neize de Moura Pereira ◽  
Tania Colombo
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Life History ◽  
Laboratory Animal ◽  
Peripheral Circulation ◽  
Experimental Conditions ◽  
History Of ◽  
The Central Nervous System ◽  
The Common ◽  
Common Laboratory

The main object of the present paper is to furnish a brief account to the knowledgement of Protozoa parasitic in common Brazilian frog of the genus Leptodactylus for general students in Zoology and for investigators that use this frog as a laboratory animal. Hepatozoon leptodactyli (Haemogregarina leptodactyli) was found in two species of frogs - Leptodactylus ocellatus and L. pentadactylus - in which develop schizogony whereas sporogony occurs in the leech Haementeria lutzi as was obtainded in experimental conditions. Intracellular forms have been found in peripheral circulation, chiefly in erythrocytes, but we have found them in leukocytes too. Tissue stages were found in frog, liver, lungs, spleen, gut, brain and heart. The occurence of hemogregarine in the Central Nervous System was recorded by Costa & al,(13) and Ball (2). Some cytochemical methods were employed in attempt to differentiate gametocytes from trophozoites in the peripheral blood and to characterize the cystic membrane as well. The speorogonic cycle was developed in only one specie of leech. A brief description of the parasite is given.

scholarly journals A STRUCTURAL ANALYSIS OF THE MYELIN SHEATH IN THE CENTRAL NERVOUS SYSTEM

1967 ◽  
Vol 34 (2) ◽  
pp. 555-567 ◽  
Author(s):  
Asao Hirano ◽  
Herbert M. Dembitzer
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Electron Microscope ◽  
Myelin Sheath ◽  
Cerebral White Matter ◽  
Experimental Conditions ◽  
Myelin Sheaths ◽  
Basic Theme ◽  
Cell Processes ◽  
The Central Nervous System

The cerebral white matter of rats subjected to a variety of noxious experimental conditions was examined in the electron microscope. Several unusual configurations of the myelin sheath are identified in addition to the usual configuration. These variations include the presence of (a) formed organelles within the inner and outer loops, (b) isolated islands of cytoplasm in unfused portions of the major dense lines, (c) apparently unconnected cell processes between the sheath and the axon, and (d) concentric, double myelin sheaths. A generalized model of the myelin sheath based on a hypothetical unrolling of the sheath is described. It consists of a shovel-shaped myelin sheet surrounded by a continuous thickened rim of cytoplasm. Most of the unusual myelin configurations are explained as simple variations on this basic theme. With the help of this model, an explanation of the formation of the myelin sheath is offered. This explanation involves the concept that myelin formation can occur at all cytoplasmic areas adjacent to the myelin proper and that adjacent myelin lamellae can move in relation to each other.

Experiments on the Origin of the Wassermann Reaction in the Cerebro-Spinal Fluid

1938 ◽  
Vol 84 (349) ◽  
pp. 370-377 ◽  
Author(s):  
A. Beck
Keyword(s):  
Central Nervous System ◽  
Cerebrospinal Fluid ◽  
Nervous System ◽  
Spinal Fluid ◽  
Experimental Conditions ◽  
Occasional Occurrence ◽  
The Central Nervous System ◽  
Wassermann Reaction

Whilst it is an undisputed fact that under certain clinical and experimental conditions various antibodies (antitoxins, agglutinins, bacterio- and hæmolysins, complement-fixing antibodies) can be demonstrated in the cerebrospinal fluid, there is a divergency of opinion about their origin. Whereas some authors (Dujardin and Dumont, Ramon, Descombey and Bilal, Neufeld and Szyle, Nélis) ascribe their presence in the cerebro-spinal fluid to their passage from the blood through a damaged blood-cerebro-spinal fluid barrier, other investigators (Mutermilch, liiert, Grabow and Plaut, Friedemann and Elkeles) believe that the central nervous system or its membranes are able to produce antibodies on their own upon contact with an antigen. In the case of the Wassermann antibody in the cerebro-spinal fluid the question of its origin is of particular interest, because of the occasional occurrence of cases which show a positive Wassermann reaction in the cerebro-spinal fluid and a negative or weaker reaction in the blood. This divergence between blood and cerebro-spinal fluid is often quoted as an example of the independence of the cerebro-spinal fluid antibody.

EFFECTS OF PROGESTERONE AND PENTOBARBITONE ON HYPOTHALAMIC INDUCTION OF OVULATION IN THE 5-DAY CYCLIC RAT

1967 ◽  
Vol 55 (3) ◽  
pp. 378-388 ◽  
Author(s):  
G. H. Zeilmaker ◽  
J. Moll
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Median Eminence ◽  
Preoptic Area ◽  
Experimental Conditions ◽  
Induced Ovulation ◽  
Ether Anaesthesia ◽  
Main Technique ◽  
The Central Nervous System ◽  
Stimulation Of

ABSTRACT The involvement of the central nervous system in the inhibitory effects on ovulation of progesterone and pentobarbitone was studied in 5-day cyclic rats. The occurrence of ovulation following electrochemical stimulation of the median eminence or the preoptic area was the main technique used in this work. The following experiments are reported. Following pretreatment with 10 mg progesterone on day 3 of the cycle stimulation of the preoptic area on day 4 was almost completely ineffective. However, stimulation of the median eminence was effective in most of these progesterone-treated rats (I). Following pretreatment with the much lower dose of 0.5 mg progesterone, spontaneous ovulation was still suppressed. However, stimulation of the preoptic area was now capable of inducing ovulations in most animals, but only if ether anaesthesia was used during the stimulation procedure. If combined pentobarbitone-ether anaesthesia was used, most animals did not ovulate (II). In other experiments stimulation of the median eminence or preoptic area was performed on day 3 (dioestrus) under ether anaesthesia or combined pentobarbitone-ether anaesthesia in normally cycling rats, which did not receive progesterone. Under ether anaesthesia preoptic stimulation induced ovulation in most animals, but under combined pentobarbitone-ether anaesthesia none of the animals ovulated (III). Stimulation in the median eminence under otherwise identical experimental conditions, induced ovulation without exceptions under ether anaesthesia and in half of the cases operated under combined pentobarbitone-ether anaesthesia (IV). It is concluded that these findings support the concept that the inhibitory effect of progesterone on ovulation is due to an action on the central nervous system. Furthermore, consideration of the possible mechanisms of action of progesterone and of pentobarbitone in inhibiting ovulation led to two alternative hypotheses: the two substances exert their effect on ovulation at the same site, or, pentobarbitone acts at a level closer to the median eminence.

Bioelectric Activity of the Brain in the Operational Personnel of the Russian Nuclear Power Plant with a Low Level of Psychophysiological Adaptation

2021 ◽  
Vol 66 (2) ◽  
pp. 29-35
Author(s):  
F. Torubarov ◽  
Z Zvereva ◽  
S. Luk'yanova
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cardiovascular System ◽  
Functional Activity ◽  
Main Role ◽  
Central Regulation ◽  
Bioelectric Activity ◽  
Low Level ◽  
The Central Nervous System ◽  
The Brain

Purpose: The aim is to study the bioelectric activity of the brain in the operational workers of the Novovoronezh and Beloyarsk nuclear power plants with a low level of psychophysiological adaptation. Material and methods: An EEG study of 101 operational employees of the NPP was conducted, visual and spectral analyses were used. EEG indicators of individuals with a low level of psychophysiological adaptation and low functional activity of structural and functional formations of the central nervous system were compared with those of individuals with a high level of adaptation, high functional activity of structural and functional formations of the central nervous system. Results: Visual analysis of individuals with a low level of psychophysiological adaptation revealed abnormal EEG indicators, indicating functional disorders of the central nervous system. The greatest violations were revealed in the structural and functional formation responsible for the central regulation of the cardiovascular system. A comparative assessment of the spectral power of the EEG at different levels of psychophysiological adaptation revealed a state of tension (tense adaptation) observed in individuals with both low and high levels of adaptation. The similarity between the structural and functional formation "central regulation of the cardiovascular system" with low functional activity and a low level of psychophysiological adaptation in terms of the number of abnormal EEG indicators can be considered as evidence of its greatest contribution to the formation of a low level of adaptation.The evaluation of interhemispheric interactions in structural and functional formations at their low and high activity, as well as at low and high levels of adaptation, suggested that the formation of a high level of psychophysiological adaptation as an integral characteristic of the main role played by the formation of the "Cortex" and "central regulation of the cardiovascular system". In the formation of a low level of psychophysiological adaptation as an integral characteristic, the main role is played by the formations "cortex" and "cortical-subcortical interaction". Conclusion: A violation of the bioelectric activity of the brain may be one of the pathogenetic mechanisms of reduced adaptation. The presence of statistically significant differences in EEG indicators in individuals with low and high levels of adaptation, revealed by visual and spectral analysis, allows us to consider these indicators as informative not only in terms of identifying deviations in the diagnosis of functional disorders, but also in assessing the effectiveness of rehabilitation and health measures.

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