scholarly journals Virulence profile of strains of Cryptococcus neoformans var. grubii evaluated by experimental infection in BALB/c mice and correlation with exoenzyme activity

2006 ◽  
Vol 55 (2) ◽  
pp. 139-142 ◽  
Author(s):  
Eriques Gonçalves da Silva ◽  
Francisco de Assis Baroni ◽  
Flavio César Viani ◽  
Luciana da Silva Ruiz ◽  
Rinaldo Ferreira Gandra ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cryptococcus Neoformans ◽  
Experimental Infection ◽  
The Other ◽  
Death Rates ◽  
Before And After ◽  
The Central Nervous System ◽  
Neurological Infection

To evaluate the virulence profile of strains of Cryptococcus neoformans var. grubii, 62 strains of this yeast were inoculated into BALB/c mice. It was found that 69 % of the strains were significantly more lethal to the mice and were recovered from a higher percentage (60 %) of the organs compared with the other 31 % of the strains, which were recovered from 35 % of organs tested. Those strains that provoked higher death rates were also recovered from the central nervous system at a higher rate (84 %) than the less lethal strains (32 %). This finding led to an investigation of the factors that enhanced the capacity for neurological infection and death of the animals. The results of this study suggested that environmental strains present different degrees of virulence. The correlation of exoenzyme production before and after inoculation and between the groups of mice indicated that exoenzyme production had no influence on differences in virulence among the strains studied.

The influence of lithium on the competence of the ectoderm in Ambystoma mexicanum

Development ◽  
1964 ◽  
Vol 12 (2) ◽  
pp. 317-331
Author(s):  
D. O. E. Gebhardt ◽  
P. D. Nieuwkoop
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Ambystoma Mexicanum ◽  
The Other ◽  
Direct Influence ◽  
Amphibian Embryos ◽  
The Central Nervous System ◽  
The Subject ◽  
Morphogenetic Potential ◽  
Made In

The influence of lithium on the amphibian egg has been the subject of a number of investigations. From the work of Lehmann (1937), Töndury (1938), and Pasteels (1945) it is known that exposure of amphibian embryos to lithium results in a progressive cranio-caudal reduction of the central nervous system and a simultaneous conversion of the presumptive notochord into somites. Whereas these experiments were made with whole embryos, attempts have been made in recent years to localize the lithium effect by transplanting or explanting specific parts of the embryo. Gallera (1949), for instance, concluded from his experiments with transplants containing lithium treated presumptive chorda mesoderm, that lithium had reduced the ‘morphogenetic potential’ of this inductor. Lombard (1952), on the other hand, claimed that the susceptibility of amphibian eggs towards lithium was the result of the ion's direct influence on the ectoderm rather than on the presumptive archenteron roof.

The Co-Ordination of Insect Movements

1957 ◽  
Vol 34 (3) ◽  
pp. 306-333
Author(s):  
G. M. HUGHES
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
The Body ◽  
The Other ◽  
Limb Amputation ◽  
Normal Movement ◽  
Thoracic Ganglia ◽  
Blatta Orientalis ◽  
The Central Nervous System ◽  
Leg Movements

I. The effects of limb amputation and the cutting of commissures on the movements of the cockroach Blatta orientalis have been investigated with the aid of cinematography. Detailed analyses of changes in posture and rhythm of leg movements are given. 2. It is shown that quite marked changes occur following the amputation of a single leg or the cutting of a single commissure between the thoracic ganglia. 3. Changes following the amputation of a single leg are immediate and are such that the support normally provided by the missing leg is taken over by the two remaining legs on that side. Compensatory movements are also found in the contralateral legs. 4. When two legs of opposite sides are amputated it has been confirmed that the diagonal sequence tends to be adopted, but this is not invariably true. Besides alterations in the rhythm which this may involve, there are again adaptive modifications in the movements of the limbs with respect to the body. 5. When both comrnissures between the meso- and metathoracic ganglia are cut, the hind pair of legs fall out of rhythm with the other four legs. The observations on the effects of cutting commissures stress the importance of intersegmental pathways in co-ordination. 6. It is shown that all modifications following the amputation of legs may be related to the altered mechanical conditions. Some of the important factors involved in normal co-ordination are discussed, and it is suggested that the altered movements would be produced by the operation of these factors under the new conditions. It is concluded that the sensory inflow to the central nervous system is of major importance in the co-ordination of normal movement.

On the incubation period in neurolues

1927 ◽  
Vol 23 (10) ◽  
pp. 1046-1050
Author(s):  
E. V. Sukhova
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Incubation Period ◽  
The Other ◽  
Other Hand ◽  
General Number ◽  
The Central Nervous System

Speaking about syphilis lesions of the central nervous system, it is impossible not to note that these lesions are among the most severe diseases of the latter. But, on the other hand, their severity is redeemed to some extent by the specific means of combating them which we have in our hands. In this case, the fight against neurolues is reduced not so much to its treatment as to its prevention. Hence the interest with which the question of the influence of various conditions on the occurrence of syphilitic lesions of the central nervous system has recently begun to be comprehensively discussed and the exact causes which, from the general number of syphilitics, distinguish the group subsequently condemned to neurolues have been sought to be elucidated.

scholarly journals Adaptation of Cryptococcus neoformans to Mammalian Hosts: Integrated Regulation of Metabolism and Virulence

2011 ◽  
Vol 11 (2) ◽  
pp. 109-118 ◽  
Author(s):  
Jim Kronstad ◽  
Sanjay Saikia ◽  
Erik David Nielson ◽  
Matthias Kretschmer ◽  
Wonhee Jung ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cryptococcus Neoformans ◽  
Central Carbon Metabolism ◽  
Yeast Cells ◽  
Phagocytic Cells ◽  
Content Type ◽  
The Central Nervous System ◽  
Mechanisms Of Adaptation ◽  
Complex Integration

ABSTRACTThe basidiomycete fungusCryptococcus neoformansinfects humans via inhalation of desiccated yeast cells or spores from the environment. In the absence of effective immune containment, the initial pulmonary infection often spreads to the central nervous system to result in meningoencephalitis. The fungus must therefore make the transition from the environment to different mammalian niches that include the intracellular locale of phagocytic cells and extracellular sites in the lung, bloodstream, and central nervous system. Recent studies provide insights into mechanisms of adaptation during this transition that include the expression of antiphagocytic functions, the remodeling of central carbon metabolism, the expression of specific nutrient acquisition systems, and the response to hypoxia. Specific transcription factors regulate these functions as well as the expression of one or more of the major known virulence factors ofC. neoformans. Therefore, virulence factor expression is to a large extent embedded in the regulation of a variety of functions needed for growth in mammalian hosts. In this regard, the complex integration of these processes is reminiscent of the master regulators of virulence in bacterial pathogens.

scholarly journals About the connections of the cerebellum with the rest of the central nervous system

2020 ◽  
Vol V (4) ◽  
pp. 16-46
Author(s):  
F. K. Telyatnik
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
The Other ◽  
Valuable Data ◽  
The Central Nervous System

Now I turn to a brief summary of the content of some of the works specially devoted to the study of the cerebellar connections. I am not trying to collect all the literature related to this issue, but will confine myself only to the latest works produced with the help of the method most commonly used at the present time for solving questions about conducting paths, namely the method of rebirth. It must be said that a great service in this relationship was also rendered by the method of development, with the help of which a lot of valuable data were obtained, especially Bekhterev. But I will not dwell on them, since all the data obtained in the works of this author are set forth in the "Conducting Ways" and are already given above. As for the newest work performed according to the method of rebirth, all of them were carried out in such a way that one or another part of the cerebellum was damaged in the animal, or one or the other of its legs, and those regenerations were observed, which followed this damage. My works were produced in the same way, and therefore it is very easy to compare them with the works of other authors. This comparison is also favored by the fact that I produced the coloring of the preparations according to the Marchi method, which was also used by most of the researchers cited below.

scholarly journals Distribution of the prion protein in sheep terminally affected with BSE following experimental oral transmission

2001 ◽  
Vol 82 (10) ◽  
pp. 2319-2326 ◽  
Author(s):  
J. D. Foster ◽  
D. W. Parnham ◽  
N. Hunter ◽  
M. Bruce
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Experimental Infection ◽  
Oral Route ◽  
Similar Distribution ◽  
Peripheral Tissues ◽  
Oral Transmission ◽  
Wide Range ◽  
Direct Contrast ◽  
The Central Nervous System

This study has examined the distribution of PrPSc in sheep by immunocytochemistry of tissues recovered from terminally affected animals following their experimental infection by the oral route with BSE. Despite a wide range of incubation period lengths, affected sheep showed a similar distribution of high levels of PrPSc throughout the central nervous system. PrPSc was also found in the lymphoid system, including parts of the digestive tract, and some components of the peripheral nervous system. These abundant PrPSc deposits in sheep in regions outside the central nervous system are in direct contrast with cattle infected with BSE, which show barely detectable levels of PrPSc in peripheral tissues. A number of genetically susceptible, challenged animals appear to have survived.

scholarly journals The Relationships between Cholesterol and Suicide: An Update

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Domenico De Berardis ◽  
Stefano Marini ◽  
Monica Piersanti ◽  
Marilde Cavuto ◽  
Giampaolo Perna ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cell Membrane ◽  
The Other ◽  
Core Component ◽  
Cell Membrane Stability ◽  
Cholesterol Levels ◽  
The Central Nervous System ◽  
Larger Sample

Cholesterol is a core component of the central nervous system, essential for the cell membrane stability and the correct functioning of neurotransmission. It has been observed that cholesterol may be somewhat associated with suicidal behaviours. Therefore, the aim of this paper was to elucidate current facts and views about the role of cholesterol levels in mood disorders. The majority of the studies reviewed in the present paper suggest an interesting relationship between cholesterol (especially lower levels) and suicidality. On the other hand, particularly during the last years, relationships between serum cholesterol and suicidality were doubted on the basis of some recent studies that have not found any correlation. However, the debate on relationships between cholesterol and suicide is open and longitudinal studies on a larger sample of patients are needed to further clarify this important issue.

Functional Evidence for Neurone Fields Representing the Individual Arms Within the Central Nervous System of Octopus

1959 ◽  
Vol 36 (3) ◽  
pp. 501-511
Author(s):  
M. J. WELLS
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Test Object ◽  
The Other ◽  
Optic Nerves ◽  
The Central Nervous System ◽  
The Individual ◽  
Tactile System

1. Octopuses blinded by section of the optic nerves were trained by means of 5-10 V. a.c. shocks to reject objects that they would otherwise take. 2. With trials at 3, 5, or 20 min. intervals, in which the test object was always presented to the same arm, animals learned within four or five trials, thereafter rejecting the test object whenever it was presented. 3. When, after a succession of such negative responses, the object was presented to another arm on the other side of the octopus, the result depended upon the rate of training before the change. Thus the object was taken in the trial immediately following the arm change in nineteen out of twenty-six sets of tests with trials at 3 or 5 min. intervals, but in only two out of twelve sets with trials at 20 min. intervals; further experiments in which changes were made between arms on the same side produced similar results. 4. These results are interpreted as showing that changes occurring as a result of experience directly affecting one arm take a period of several hours to spread and become effective in determining the reactions of the rest. This in turn implies the existence of functionally independent neurone fields representing the individual arms, and is discussed in relation to what is already known about the organization of the tactile system of the octopus.

Effects of hypercapnia and hypoxia on inspiratory and expiratory diaphragmatic activity in conscious cats

1994 ◽  
Vol 77 (4) ◽  
pp. 1644-1652 ◽  
Author(s):  
M. Bonora ◽  
M. Boule
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Steady State ◽  
Electromyographic Activity ◽  
Large Reduction ◽  
Before And After ◽  
The Central Nervous System ◽  
State Changes ◽  
Chemical Stimuli ◽  
Adult Cats

The influence of steady-state changes in chemical stimuli on ventilation and electromyographic activity of the diaphragm during both inspiration (total DI) and expiration (total DE) was studied in unanesthetized intact adult cats before and after carotid denervation. In intact animals, during hypercapnia (2 4, and 6% CO2), tidal volume (VT) and total DI increase, whereas total DE did not consistently change. During ambient hypocapnic hypoxia (14, 12, and 10% O2), VT increased only at 10% O2, whereas total DI increased at all levels studied. Total DE increased substantially at 14% O2, persisting up to the end of expiration with 12 and 10% O2. This effect was markedly attenuated during normocapnic hypoxia. During CO hypoxemia (1,700 ppm in air), VT as well as total DI and total DE decreased because of a large reduction in inspiratory and expiratory time elicited by tachypneic breathing. The effects of hypercapnia and hypoxia persisted after carotid denervation. Therefore, 1) in contrast to hypercapnia, hypoxia markedly enhances the expiratory diaphragmatic activity, 1) this expiratory braking mechanism depends on the severity of hypoxia and is partly due to hypocapnia secondary to hypoxia; and 3) because this effect was observed after carotid denervation and during CO hypoxemia, it may arise in the central nervous system, possibly in bulbopontine structures.

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