The Distribution of a Particulate Component of Membranes in Brain and Retina

1967 ◽  
Vol 25 ◽  
pp. 200-201
Author(s):  
Kuniyuki Someda ◽  
Ronald S. Weinstein
Keyword(s):  
Nervous System ◽  
Cerebral Cortex ◽  
Nervous Tissue ◽  
Particle Distribution ◽  
Fracture Face ◽  
Small Particles ◽  
Razor Blade ◽  
Membrane Ultrastructure ◽  
Membrane Components ◽  
Individual Particles

Replicas of fracture faces along a variety of frozen membranes have revealed a particulate component, with replicas of individual particles measuring 100 to 200 Å in diameter. The relation of these small particles to membrane ultrastructure is questionable and there is even some controversy as to whether the particles represent true membrane components, material adsorbed onto membranes from adjacent compartments, or a contaminent adsorbed onto the frozen fracture face prior to replication with carbon and platinum. In this study, replicas of fracture faces of frozen nervous tissue were surveyed in an effort to find if consistent patterns of particle distribution could be demonstrated on nervous system membranes.Rat retinas, cerebral cortex and corpus callosum were protected with glycerol or dimethylsulfoxide and freeze-fractured with a razor blade in a three tier apparatus as described in detail by Bullivant and Ames.1 Following replication in an evaporator (Kinney PW 400), the tissue was dissolved and fragments of replica were washed, picked up on grids and examined in the electron microscope. No etching, as it is defined by Moor, was involved in producing these fracture faces for replication.

Glucuronyl 3-sulfate occurs exclusively on distal unmyelinated terminals of selected sensory neurons in the peripheral nervous system

1995 ◽  
Vol 53 ◽  
pp. 958-959
Author(s):  
S.S. Spicer ◽  
B.A. Schulte
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cerebral Cortex ◽  
Peripheral Nervous System ◽  
Sensory Neurons ◽  
Sensory Nerves ◽  
Tissue Antigens ◽  
The Central Nervous System ◽  
The Brain ◽  
Leu 7

Generation of monoclonal antibodies (MAbs) against tissue antigens has yielded several (VC1.1, HNK- 1, L2, 4F4 and anti-leu 7) which recognize the unique sugar epitope, glucuronyl 3-sulfate (Glc A3- SO4). In the central nervous system, these MAbs have demonstrated Glc A3-SO4 at the surface of neurons in the cerebral cortex, the cerebellum, the retina and other widespread regions of the brain.Here we describe the distribution of Glc A3-SO4 in the peripheral nervous system as determined by immunostaining with a MAb (VC 1.1) developed against antigen in the cat visual cortex. Outside the central nervous system, immunoreactivity was observed only in peripheral terminals of selected sensory nerves conducting transduction signals for touch, hearing, balance and taste. On the glassy membrane of the sinus hair in murine nasal skin, just deep to the ringwurt, VC 1.1 delineated an intensely stained, plaque-like area (Fig. 1). This previously unrecognized structure of the nasal vibrissae presumably serves as a tactile end organ and to our knowledge is not demonstrable by means other than its selective immunopositivity with VC1.1 and its appearance as a densely fibrillar area in H&E stained sections.

Neurofilament phosphorylation

1995 ◽  
Vol 73 (9-10) ◽  
pp. 575-592 ◽  
Author(s):  
Harish C. Pant ◽  
Veeranna
Keyword(s):  
Molecular Weight ◽  
Nervous System ◽  
Nervous Tissue ◽  
Important Determinant ◽  
Neurofilament Proteins ◽  
Neurofilament Phosphorylation ◽  
Axonal Compartment

Neurofilament proteins (NFPs) are highly phosphorylated molecules in the axonal compartment of the adult nervous system. The phosphorylation of NFP is considered an important determinant of filament caliber, plasticity, and stability. This process reflects the function of NFs during the lifetime of a neuron from differentiation in the embryo through long-term activity in the adult until aging and environmental insult leads to pathology and ultimately death. NF function is modulated by phosphorylation–dephosphorylation in each of these diverse neuronal states. In this review, we have summarized some of these properties of NFP in adult nervous tissue, mostly from work in our own laboratory. Identification of sites phosphorylated in vivo in high molecular weight NFP (NF-H) and properties of NF-associated and neural-specific kinases phosphorylating specific sites in NFP are described. A model to explain the role of NF phosphorylation in determining filament caliber, plasticity, and stability is proposed.Key words: neurofilament proteins, phosphorylation, kinases, phosphatases, regulators, inhibitors, multimesic complex, domains.

Particle regularity on thylakoid fracture faces is influenced by storage conditions

1995 ◽  
Vol 73 (10) ◽  
pp. 1676-1682 ◽  
Author(s):  
Galina A. Semenova
Keyword(s):  
Particle Density ◽  
Freeze Fracture ◽  
Storage Conditions ◽  
Medium Composition ◽  
Prolonged Storage ◽  
Particle Sizes ◽  
Fracture Face ◽  
Small Particles ◽  
Mean Size ◽  
Regular Arrays

Specific temperature, storage times, and medium composition enable initiation of regular arrays of intramembranous particles on the exoplasmic fracture face during prolonged storage of isolated chloroplasts at 4 °C, producing about 2 – 10 regular arrays with 2 – 30 particles in each array, with a period of about 36 nm, oriented in 1 – 4 directions. The particle sizes do not change throughout the time of storage (1 – 4 weeks). The second type of particle regularity arises during prolonged storage of chloroplasts in greater than 1 M sucrose at −18 °C. Rounded areas of small particles tightly packed into paracrystalline arrays are found among less densely packed particles. The density of small particles is 4700 particles/μm2, and the mean size is 11 nm, whereas the particle density of the background is 1600 particles/μm2 with a mean particle size of 13 nm compared with 1200 particles/μm2 and mean size 16 nm in fresh chloroplasts. Based on the reduction of particle sizes and manner of packing on the fracture face, it is proposed that the small particles are a light-harvesting complex, separate from photosystem II and aggregated into paracrystalline arrays. The thylakoid lipids may participate in formation of particle regularity. Key words: thylakoid membrane, freeze fracture, particle regularity, low temperatures.

Changes in the Cortex Neurons in Single and Fractional Gamma Radiation

2021 ◽  
Vol 66 (4) ◽  
pp. 18-24
Author(s):  
I. Ushakov ◽  
Vladimir Fyodorov
Keyword(s):  
Nervous System ◽  
Cerebral Cortex ◽  
Radiation Exposure ◽  
Comparative Assessment ◽  
Male Rats ◽  
Fractionated Irradiation ◽  
Radiation Induced ◽  
Post Radiation ◽  
Induced Changes ◽  
The Brain

Purpose: Comparative assessment of radiation-induced changes in neurons of the cerebral cortex after a single and fractionated exposure to ionizing radiation in doses of 0.1 – 1.0 Gy. Material and methods. The study was carried out in compliance with the rules of bioethics on 180 white outbred male rats at the age of 4 months. by the beginning of the experiment, exposed to a single or fractionated exposure to γ-quanta of 60Co in total doses of 0.1; 0.2; 0.5 and 1.0 Gy. Neuromorphological and histochemical methods were used to assess morphometric and tinctorial parameters of nerve cells, as well as changes in the content of protein and nucleic acids in neurons in the early and late periods of the post-radiation period. Using one-way analysis of variance, a comparative assessment of neuromorphological indicators under various modes of radiation exposure is given. Results: In the control and irradiated animals throughout their life, undulating changes in the indicators of the state of the neurons of the brain occur with a gradual decrease by the end of the experiment. Despite a number of features of the dynamics of neuromorphological parameters, these irradiation regimes do not cause functionally significant changes in the neurons of the cortex. However, in some periods of the post-radiation period, the changes under the studied irradiation regimes were multidirectional and did not always correspond to age control. Significant differences in the response of neurons to these modes of radiation exposure in the sensory and motor areas of the cerebral cortex have not been established. Conclusion: No functionally significant radiation-induced changes in neurons were found either with single or fractionated irradiation. At the same time, different modes of irradiation in general caused the same type of changes in neurons. However, in some periods of observation, changes in neuromorphological parameters under the studied irradiation regimes were not unidirectional and differed from age control, which indicates a possible risk of disturbances in the functioning of the nervous system against the background of other harmful and dangerous factors.

Serologic differentiation of peripheral nerves (especially the autonomic nervous system) from the cerebral cortex

1935 ◽  
Vol 31 (7) ◽  
pp. 909-909
Author(s):  
F. Plaut
Keyword(s):  
Nervous System ◽  
Cerebral Cortex ◽  
Autonomic Nervous System ◽  
Peripheral Nerves ◽  
Autonomic Nervous

The author showed that the sera obtained by immunizing rabbits with a suspension of n. sympathicus and n. vagus, do not show specific properties when tested with alcoholic extracts from the same nerves; these serums have only the properties of ordinary neuroanti-serums.

Influence of ionizing radiations on the development of the nervous system

1967 ◽  
Vol 16 (3) ◽  
pp. 275-309 ◽  
Author(s):  
W. Geets
Keyword(s):  
Nervous System ◽  
Cerebral Cortex ◽  
Research Work ◽  
Low Doses ◽  
Embryonic Period ◽  
Clinical Observations ◽  
Functional Maturation ◽  
Maturation Stages ◽  
Mother Cells ◽  
Ionizing Radiations

SUMMARYThe first cellular differentiation in the process of segmentation leads to the embryonic period, the major organogenetic period for the nervous system. In man, it appears between the second and the eighth week after conception.During the foetal and perinatal periods, the nervous organization mainly develops at the cerebellum and cerebral cortex levels. The cerebrum functional maturation continues well beyond birth.Neuroblasts are the most widespread mother-cells in the developing nervous system during the embryonic period, but some are still to be found after birth.Animal experiment has demonstrated that ionizing radiations were able to disorganize neurogenesis in any of its maturation stages, even at very low doses. It is possible to establish a chronological table showing the anatomical or functional deformities in relation with the embryonic age at which rays have been given.It appears that in man the most dangerous period is between the beginning of the second and the end of the eighth week after conception. At that moment, pregnancy is often ignored and a dose of 20 to 40 r is sufficient to entail serious damages, such as microcephaly, protrusions of the brain or mental retardation. On drawing near to birth the foetal or neonatal nervous system of rodents or primates is still radiosensitive, especially at the cerebral cortex level and the consequences will be of a neurophysiologic or psychosensorial nature. Certain embryopathies or neurologic alterations would only be apparent in subsequent generations, following mutations induced into the mother-cells of the nervous system. Genetic deformities of the nervous system can also result from moderate irradiations of the gonads.Further to the precise experimental research work on the radiovulnerability of the embryonic or foetal nervous system of the animal, certain clinical observations are presented, which lead to similar conclusions.The atomic bombardments have caused numerous neurological trouble among the children who had been irradiated in utero. And the genetic effects are not yet perfectly known to-date.This set of experimental and clinical data must prompt us to be very careful when using ionizing radiations, even at low doses, in pregnant women and newborn.

scholarly journals Therapeutic significance of hemorrhages in suffering from the nervous system

2021 ◽  
Vol XII (3) ◽  
pp. 246-283
Author(s):  
A. V. Sobolevsky
Keyword(s):  
Blood Pressure ◽  
Nervous System ◽  
Cerebral Cortex ◽  
Sharp Increase

Orleansky one experiment with strangulation was put on a dog, in which 4 days before that part of the cerebral cortex was removed from both sides, the irritation of which, according to prof. Bekhterev and Mislavsky, produces, as a constant phenomenon, a sharp increase in blood pressure.

Biotransport to the Cerebral Tissues Related to the Vascular Diseases

2008 ◽  
Author(s):  
Kazuo Tanishita ◽  
Kazuto Masamoto ◽  
Iwao Kanno ◽  
Hirosuke Kobayashi
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cerebral Cortex ◽  
Oxygen Transport ◽  
Consumption Rate ◽  
Vascular Diseases ◽  
Selective Vulnerability ◽  
Whole Body ◽  
Sensorimotor Function ◽  
Irreversible Damage

Brain is a highly oxidative organ and its consumption rate of oxygen accounts for 20 percent of that of the whole body. This large consumption rate must be met by continuous supply of oxygen, because lack of oxygen rapidly causes irreversible damage to central nervous system. Acute hypoxic episodes cause a certain pattern of regional damage. Cerebral cortex (e.g., layers III, V, and VI) is one of the most susceptible regions to hypoxia, and damage to sensorimotor function is particularly severe in humans that survive hypoxic/ischemic episodes. However, little is known about whether oxygen transport in intracortical regions relates to such selective vulnerability to hypoxia.

Urea transport in the central nervous system

1962 ◽  
Vol 203 (4) ◽  
pp. 739-747 ◽  
Author(s):  
Charles R. Kleeman ◽  
Hugh Davson ◽  
Emanuel Levin
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Nervous Tissue ◽  
Urea Transport ◽  
Major Barrier ◽  
Rate Of Penetration ◽  
The Central Nervous System ◽  
Kinetics Of ◽  
The Brain ◽  
State Content

The kinetics of urea transport in the central nervous system have been studied in rabbits during sustained intravenous and intracisternal infusions of C12 and C14 urea. The steady state content of urea in the water phase of the white matter and cord was approximately equal to its content in plasma water. However, the water of whole brain and gray matter had levels of urea which exceeded those in plasma by 7 and 18%, respectively, whereas the urea in cerebrospinal fluid (CSF) was only 78% of the plasma level. Its rate of penetration into nervous tissue was approximately one-tenth as rapid as into muscle. The intravenous infusion of urea caused a significant decrease in water content of the brain and cord. It was estimated that urea infused into the subarachnoid space penetrated the central nervous system (CNS) tissues at four to five times the rate of transport from blood to CNS tissues. These studies suggest that intravenous infusions of urea lower CSF pressure by decreasing the volume of the brain and cord. The major barrier to urea penetration into nervous tissue is at the capillary level, and not the plasma membrane of the glial or neuronal cells.

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