Exo-erythrocytic schizogony in Plasmodium gallinaceum Brumpt, 1935

Parasitology ◽  
1938 ◽  
Vol 30 (1) ◽  
pp. 128-139 ◽  
Author(s):  
S. P. James ◽  
P. Tate
Keyword(s):  
Peripheral Circulation ◽  
Blood Stream ◽  
The Body ◽  
Plasmodium Gallinaceum ◽  
Large Size ◽  
Peripheral Infection ◽  
The Brain ◽  
Reticulo Endothelial System ◽  
Sporozoite Infection ◽  
In Cells

In Plasmodium gallinaceum, parasitic in domestic fowls, in addition to the schizogony in red blood corpuscles, schizogony also occurs in monocytes and cells of the reticulo-endothelial system. This schizogony in cells other than erythrocytes may be termed, for convenience, exo-erythrocytic schizogony.Exo-erythrocytic schizonts are characterized by never having malarial pigment (as they live in cells devoid of haemoglobin), by growing to a large size and forming numerous merozoites, up to 50 or 60 or even more.Exo-erythrocytic schizonts are not confined to leucocytes of the blood stream, but can also develop in fixed endothelial cells of organs such as the brain, lung, liver and spleen.The brain is an especially important focus of development and, after sporozoite infection, it is the first organ in which exo-erythrocytic schizonts develop. These schizonts may be found in capillaries of the brain as soon as parasitized erythrocytes are present in the peripheral circulation, but as yet they have not been found before parasites-are present in the peripheral blood.In the brain rows of schizonts may develop and ultimately occlude most of the capillaries in the brain. This blockage of capillaries results in symptoms of general paralysis in the infected birds and death follows in a few days; and it frequently occurs in birds which apparently have been cured of the peripheral infection by treatment with quinine.The exo-erythrocytic stages of P. gallinaceum occur in birds which have been inoculated with blood or with sporozoites.During growth, the body of the schizont breaks up into a number of masses or cytomeres, on the periphery of which the merozoites are developed on regularly arranged rows of digitiform processes. A mass of chromatin migrates to the distal end of each process and is cut off to form a merozoite.The mature schizont consists of a mass of irregular merozoites enclosed in a sac-like membrane which may be the remains of the host cell. The merozoites are composed almost entirely of chromatin and when they are fully developed practically no cytoplasm of the schizont remains.

scholarly journals STUDIES ON VITAL STAINING

1930 ◽  
Vol 51 (3) ◽  
pp. 379-394 ◽  
Author(s):  
H. P. Smith
Keyword(s):  
Vital Staining ◽  
Blood Stream ◽  
Partition Ratio ◽  
The Body ◽  
Phagocytic Cells ◽  
Bile Fistula ◽  
Prolonged Retention ◽  
Large Dosage ◽  
Partial Correction ◽  
Reticulo Endothelial System

Brilliant vital red injected into the blood stream of dogs is slowly taken up by phagocytes in various parts of the body, but eventually an equilibrium is established, after which the concentration as measured in the plasma remains almost constant for long intervals of time. This equilibrium can be disturbed by injecting more dye, and in this case the phagocytes resume ingestive activity, apparently with normal or nearly normal vigor. This activity continued until a rather large part of the newly injected dye has been removed, and as the reaction again slows up we note that both plasma and tissues contain more dye than before. It is difficult to be certain that the distribution ratio of dye between plasma and tissues remains unaltered with dosage, but evidence indicates that for non toxic doses, at least, this is approximately true. This study of this partition ratio is complicated by the fact that the liver slowly excretes dye into the bile, and this helps to reduce the amount of dye in the body. Partial correction for this factor can be made by ascertaining the dye output in bile fistula dogs. These latter studies show that dye elimination into bile is relatively less efficient when large doses of dye are given to the animal than with smaller dosage. This undue retention of dye in the body with large dosage helps to maintain the dye concentration in the plasma at unduly high levels. These peculiarities in liver excretion have an important bearing on liver physiology in general, and in addition they also have an important application in connection with the theory of "blockade of the reticulo-endothelial system." It is now obvious that prolonged retention of dye in the blood stream does not of itself prove that this group of phagocytic cells is "blocked" against the entrance of foreign material. Altered excretion by liver, kidney, etc. must be ruled out before we can accept such data as evidence of "blockade."

Diatoms and Forensic Science

2007 ◽  
Vol 13 ◽  
pp. 181-190
Author(s):  
Benjamin P. Horton
Keyword(s):  
Forensic Science ◽  
Cause Of Death ◽  
Blood Stream ◽  
The Body ◽  
Naturally Occurring ◽  
Analogue Matching ◽  
Informal Assessment ◽  
Diatom Test ◽  
The Brain ◽  
Site Of Drowning

The application of diatom analysis in determining whether drowning was the cause of death has proved to be a valuable tool in forensic science. The basic principal of the “diatom test” in drowning is based on inference that diatoms are present in the medium where the possible drowning took place and that the inhalation of water causes penetration of diatoms into the alveolar system and blood stream, and thus, their deposition into the brain, kidneys, and other organs.I provide an informal assessment of “reliability” of the “diatom test” through correlations between control samples and samples from organs and clothing in two case studies. In studies, all organ and clothing samples except one had matching analogues in the modern diatom dataset from the body recovery sites, reinforcing drowning as the cause of death. The analogue matching provides further information on the precise site of drowning, in particular differentiating between drowning in a bathtub versus a naturally occurring body of water.

On the invasion of the central nervous system by nematodes: II. Invasion of the nervous system in ascariasis

Parasitology ◽  
1955 ◽  
Vol 45 (1-2) ◽  
pp. 41-55 ◽  
Author(s):  
J. F. A. Sprent
Keyword(s):  
Nervous System ◽  
Toxocara Canis ◽  
Blood Stream ◽  
Experimental Infections ◽  
Large Size ◽  
Arterial Blood ◽  
The Central Nervous System ◽  
The Brain ◽  
Traumatic Damage ◽  
Toxascaris Leonina

1. Experimental infections in mice showed that the larvae of Toxocara canis, T. mystax, Ascaris devosi, A. columnaris and Toxascaris transfuga reached the brain of mice; the larvae of Ascaris lumbricoides, A. suum, Parascaris equorum and Toxascaris leonina were not recovered from the brain. The larvae of T. canis, T. mystax, T. transfuga and A. columnaris remained hi the brain of mice for several months.2. Larvae reaching the brain produced characteristic haemorrhages on the surface of the cerebral hemispheres in the early stages of infection. It was concluded that the larvae reach the brain via the arterial blood stream, leave the arteries at the point where their diameter approximates that of the larvae, i.e. mostly on the surface of the brain, and penetrate into the brain from the subarachnoid space and chorioidal tissues.3. The larvae of T. canis were found to occur in the brain of mice in relatively greater numbers than the larvae of other species, but only very rarely caused nervous symptoms. The larvae of T. canis and T. mystax showed no growth in the brain.4. The larvae of A. columnaris (skunk) frequently caused nervous symptoms in mice, the effect appeared to result from traumatic damage due to the relatively large size attained by these larvae about 3 weeks after infection.5. The brain of infected mice showed very slight changes consequent upon infection with larvae of T. canis. These larvae moved actively through the tissues; they incited little or no cellular reaction, but left haemorrhagic tracks. The larvae of A. columnaris also moved actively; when in the extended state they were usually found in normal tissue; when coiled, they were often associated with a necrotic focus infiltrated with leucocytes.6. After experimental infections of dogs with larvae of T. canis, two out of twelve infected animals harboured larvae in the brain. No natural infections with these larvae were found in the brains of dogs and cats. After experimental infection, larvae of T. canis were found in the brain of mice, rats and guinea-pigs, but not of rabbits.7. Larvae of A. suum were recovered from the cerebrum of one pig suffering from posterior paralysis, but not in an experimentally infected pig.8. No larvae of P. equorum were found in the brain of foals in natural and experimental infections.

The Blood Vascular System of Nephtys (Annelida, Polychaeta)

1956 ◽  
Vol s3-97 (38) ◽  
pp. 235-249
Author(s):  
R. B. CLARK
Keyword(s):  
Body Wall ◽  
Vascular System ◽  
Close Association ◽  
Circulatory System ◽  
Ventral Surface ◽  
Blood Stream ◽  
Neurosecretory Cells ◽  
The Body ◽  
Dorsal Vessel ◽  
The Brain

The four longitudinal vessels of the circulatory system of Nephtys californiensis are dorsal, sub-intestinal, and neural, the latter being paired. There is a complete longitudinal circulation; the dorsal vessel communicates with the sub-intestinal by way of the proboscidial circulation and with the neural by way of the circum-oral vessels. In each middle and posterior segment segmental vessels from each of the longitudinal trunks carry blood to and from the parapodia and body-wall. The segmental circulation is completed by a circum-intestinal vessel connecting the dorsal and subintestinal vessels in each segment and an intersegmental branch connecting the dorsal and sub-intestinal segmental vessels. A trans-septal branch of the neural segmental vessel communicates with the sub-intestinal segmental vessel. This arrangement is modified in anterior segments which house the muscular, eversible pharynx, and no blood-vessels cross the coelom except by running through the body-wall. On anatomical grounds and by comparison with other polychaetes it seems likely that segmental is subordinate to longitudinal circulation. There are no endothelial capillaries such as have been described in some other polychaetes; instead there are numerous blindending vessels the walls of which are composed of the same three layers as other vessels and which are probably contractile. The dorsal vessel, where it is in contact with the ventral surface of the supra-oesophageal ganglion, forms a plexus in close association with a modified part of the brain capsule and a special axonal tract within the ganglion. It is thought that by way of this ‘cerebro-vascular complex’, hormones produced in the neurosecretory cells of the brain pass into the blood-stream.

scholarly journals Balancing cholesterol in the brain: from synthesis to disposal

2022 ◽  
pp. 1-27
Author(s):  
Lydia Qian ◽  
Amanda B. Chai ◽  
Ingrid C. Gelissen ◽  
Andrew J. Brown
Keyword(s):  
De Novo ◽  
Cholesterol Metabolism ◽  
Peripheral Circulation ◽  
The Body ◽  
Cholesterol Homeostasis ◽  
Myelin Sheaths ◽  
The Central Nervous System ◽  
Vital Component ◽  
The Brain ◽  
Limited Exchange

The cholesterol is a vital component of cell membranes and myelin sheaths, and a precursor for essential molecules such as steroid hormones. In humans, cholesterol is partially obtained through the diet, while the majority is synthesized in the body, primarily in the liver. However, the limited exchange between the central nervous system and peripheral circulation, due to the presence of the blood-brain barrier, necessitates cholesterol in the brain to be exclusively acquired from local de novo synthesis. This cholesterol is reutilized efficiently, rendering a much slower overall turnover of the compound in the brain as compared with the periphery. Furthermore, brain cholesterol is regulated independently from peripheral cholesterol. Numerous enzymes, proteins, and other factors are involved in cholesterol synthesis and metabolism in the brain. Understanding the unique mechanisms and pathways involved in the maintenance of cholesterol homeostasis in the brain is critical, considering perturbations to these processes are implicated in numerous neurodegenerative diseases. This review focuses on the developing understanding of cholesterol metabolism in the brain, discussing the sites and processes involved in its synthesis and regulation, as well as the mechanisms involved in its distribution throughout, and elimination from, the brain.

scholarly journals Through the Open Window: How Does the Brain Talk to the Body?

2021 ◽  
Vol 9 ◽  
Author(s):  
Ludmila Gordon ◽  
Gil Levkowitz
Keyword(s):  
Blood Pressure ◽  
Blood Vessels ◽  
Blood Stream ◽  
The State ◽  
The Body ◽  
Brain Cells ◽  
Open Window ◽  
Food Digestion ◽  
The Brain ◽  
Sleep Cycles

The brain controls the activities of the body, including food digestion, drinking, sleep cycles, temperature, blood pressure, and more. These functions are essential to keep the body in homeostasis, which is the state of being steady and balanced. To control homeostasis, the brain talks to the body with the help of chemical messengers called hormones. Hormones travel through the blood stream from the brain to the body and back. However, in order to protect the delicate brain cells from unwanted intrusions, the blood vessels of the brain are tightly sealed, preventing the passage of most molecules. How, then, does the brain bypass this barrier to communicate with the body? The answer is that, in certain parts of the brain, the blood vessels contain special window-like openings that allow passage of hormones. Scientists are investigating why and how some blood vessels open their windows while others remain sealed.

EXPERIMENTAL ASSESSMENT OF THE NANOPARTICLES TOXICITY OF NICKEL OXIDE IN TWO SIZES IN THE SUBCHRONIC EXPERIMENT

2018 ◽  
pp. 30-35
Author(s):  
M.P. Sutunkova ◽  
B.A. Katsnelson ◽  
L.I. Privalova ◽  
S.N. Solovjeva ◽  
V.B. Gurvich ◽  
...  
Keyword(s):  
Nickel Oxide ◽  
Nervous Activity ◽  
Equal Mass ◽  
The Body ◽  
Subchronic Toxicity ◽  
Physiological Mechanisms ◽  
Nickel Oxide Nanoparticles ◽  
The Relationship ◽  
The Brain ◽  
Nanoparticles Toxicity

We conducted a comparative assessment of the nickel oxide nanoparticles toxicity (NiO) of two sizes (11 and 25 nm) according to a number of indicators of the body state after repeated intraperitoneal injections of these particles suspensions. At equal mass doses, NiO nanoparticles have been found to cause various manifestations of systemic subchronic toxicity with a particularly pronounced effect on liver, kidney function, the body’s antioxidant system, lipid metabolism, white and red blood, redox metabolism, spleen damage, and some disorders of nervous activity allegedly related to the possibility of nickel penetration into the brain from the blood. The relationship between the diameter and toxicity of particles is ambiguous, which may be due to differences in toxicokinetics, which is controlled by both physiological mechanisms and direct penetration of nanoparticles through biological barriers and, finally, unequal solubility.

The musculature and nervous system of the plerocercoid larva of Dibothriorhynchus grossum (Rud.)

Parasitology ◽  
1941 ◽  
Vol 33 (4) ◽  
pp. 373-389 ◽  
Author(s):  
Gwendolen Rees
Keyword(s):  
Nervous System ◽  
Muscle Mass ◽  
Nerve Cells ◽  
The Body ◽  
Lateral Nerve ◽  
Posterior Median ◽  
The Brain ◽  
Ventral Muscle ◽  
Nerve Cords ◽  
Extrinsic Muscles

1. The structure of the proboscides of the larva of Dibothriorhynchus grossum (Rud.) is described. Each proboscis is provided with four sets of extrinsic muscles, and there is an anterior dorso-ventral muscle mass connected to all four proboscides.2. The musculature of the body and scolex is described.3. The nervous system consists of a brain, two lateral nerve cords, two outer and inner anterior nerves on each side, twenty-five pairs of bothridial nerves to each bothridium, four longitudinal bothridial nerves connecting these latter before their entry into the bothridia, four proboscis nerves arising from the brain, and a series of lateral nerves supplying the lateral regions of the body.4. The so-called ganglia contain no nerve cells, these are present only in the posterior median commissure which is therefore the nerve centre.

scholarly journals The brain dynamics of architectural affordances during transition

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zakaria Djebbara ◽  
Lars Brorson Fich ◽  
Klaus Gramann
Keyword(s):  
Occipital Cortex ◽  
The Body ◽  
Brain Dynamics ◽  
Alpha Band ◽  
Time Frequency ◽  
Posterior Cingulate ◽  
Sensory Signals ◽  
Event Related Desynchronization ◽  
The Brain ◽  
Attentional Mechanisms

AbstractAction is a medium of collecting sensory information about the environment, which in turn is shaped by architectural affordances. Affordances characterize the fit between the physical structure of the body and capacities for movement and interaction with the environment, thus relying on sensorimotor processes associated with exploring the surroundings. Central to sensorimotor brain dynamics, the attentional mechanisms directing the gating function of sensory signals share neuronal resources with motor-related processes necessary to inferring the external causes of sensory signals. Such a predictive coding approach suggests that sensorimotor dynamics are sensitive to architectural affordances that support or suppress specific kinds of actions for an individual. However, how architectural affordances relate to the attentional mechanisms underlying the gating function for sensory signals remains unknown. Here we demonstrate that event-related desynchronization of alpha-band oscillations in parieto-occipital and medio-temporal regions covary with the architectural affordances. Source-level time–frequency analysis of data recorded in a motor-priming Mobile Brain/Body Imaging experiment revealed strong event-related desynchronization of the alpha band to originate from the posterior cingulate complex, the parahippocampal region as well as the occipital cortex. Our results firstly contribute to the understanding of how the brain resolves architectural affordances relevant to behaviour. Second, our results indicate that the alpha-band originating from the occipital cortex and parahippocampal region covaries with the architectural affordances before participants interact with the environment, whereas during the interaction, the posterior cingulate cortex and motor areas dynamically reflect the affordable behaviour. We conclude that the sensorimotor dynamics reflect behaviour-relevant features in the designed environment.

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