A Study of Terminal Degeneration in the Olfactory Bulb of the Rat

1972 ◽  
Vol 10 (3) ◽  
pp. 585-619
Author(s):  
A. J. PINCHING ◽  
T. P. S. POWELL
Keyword(s):  
Olfactory Bulb ◽  
Synaptic Cleft ◽  
Olfactory Nerve ◽  
Synaptic Membrane ◽  
Morphological Identification ◽  
Axon Terminals ◽  
Quantitative Characteristics ◽  
Terminal Degeneration ◽  
Qualitative And Quantitative Characteristics

An ultrastructural study of degeneration in axon terminals of the glomerular layer of the rat olfactory bulb is described, concentrating particularly on the sequence of degeneration in the olfactory nerve terminals and the long-term events in the degeneration process in several terminal types. Olfactory nerve terminal degeneration is divided into 5 stages, representing parts of the sequential changes taking place in the terminal after fibre section. The main features in the sequence are as follows: I. Swelling of the terminal and its vesicles. II. Initial shrinkage of the terminal, while vesicles remain swollen and some are distorted. III. Further shrinkage and darkening of the terminal, distortion of many of the vesicles and some mitochondrial swelling. IV. Extreme shrinkage of the terminal and loss of cytoplasmic detail; synaptic contact still intact or partially separated. V. Disappearance of the presynaptic terminal and persistence of the post-synaptic thickening. The validity of the observation of the persistence of post-synaptic membrane thickenings is considered and evidence adduced in its favour, both qualitative and quantitative. Characteristics of the newly apposed profiles are described, including cisternae and alveolate vesicles; the extracellular material of the synaptic cleft is considered in the light of its association with persisting thickenings. The relevance of these associated Structures is discussed in terms of function and development. Spontaneous degeneration of olfactory nerves and the degeneration of the vomeronasal nerves in the accessory olfactory bulb are described, as well as Stage V in the degeneration of other terminal types of the glomeruli, following various lesions; persistence of post-synaptic thickenings after the degeneration of terminals showing symmetrical membrane thickenings is included. Observations on the persistence of post-synaptic thickenings in various sites in the central and peripheral nervous systems are reviewed in the context of the present study; the problems arising out of the morphological identification of apposition or reinnervations are discussed.

scholarly journals The Curious Anti-Pathology of the Wlds Mutation: Paradoxical Postsynaptic Spine Growth Accompanies Delayed Presynaptic Wallerian Degeneration

2021 ◽  
Vol 14 ◽  
Author(s):  
Oswald Steward ◽  
Jennifer M. Yonan ◽  
Paula M. Falk
Keyword(s):  
Wallerian Degeneration ◽  
Granule Cells ◽  
Long Term Potentiation ◽  
Perforant Path ◽  
Synaptic Membrane ◽  
Term Potentiation ◽  
Terminal Degeneration ◽  
Synapse Degeneration ◽  
Degenerating Axons

The Wlds mutation, which arose spontaneously in C57Bl/6 mice, remarkably delays the onset of Wallerian degeneration of axons. This remarkable phenotype has transformed our understanding of mechanisms contributing to survival vs. degeneration of mammalian axons after separation from their cell bodies. Although there are numerous studies of how the Wlds mutation affects axon degeneration, especially in the peripheral nervous system, less is known about how the mutation affects degeneration of CNS synapses. Here, using electron microscopy, we explore how the Wlds mutation affects synaptic terminal degeneration and withering and re-growth of dendritic spines on dentate granule cells following lesions of perforant path inputs from the entorhinal cortex. Our results reveal that substantial delays in the timing of synapse degeneration in Wlds mice are accompanied by paradoxical hypertrophy of spine heads with enlargement of post-synaptic membrane specializations (PSDs) and development of spinules. These increases in the complexity of spine morphology are similar to what is seen following induction of long-term potentiation (LTP). Robust and paradoxical spine growth suggests yet to be characterized signaling processes between amputated but non-degenerating axons and their postsynaptic targets.

The Synaptology of the Granule Cells of the Olfactory Bulb

1970 ◽  
Vol 7 (1) ◽  
pp. 125-155
Author(s):  
J. L. PRICE ◽  
T. P. S POWELL
Keyword(s):  
Olfactory Bulb ◽  
Synaptic Vesicles ◽  
Granule Cells ◽  
Mitral Cell ◽  
Synaptic Membrane ◽  
Quantitative Evidence ◽  
Axon Terminals ◽  
Quantitative Measurements ◽  
Asymmetrical Synapse ◽  
Cell Somata

The synapses related to the granule cells of the olfactory bulb of rat brain have been studied in aldehyde-fixed material. The synapses can be divided into three classes: (1) those which have asymmetrical synaptic membrane thickenings and spheroidal synaptic vesicles; (2) those with symmetrical synaptic thickenings and flattened vesicles; and (3) the reciprocal synapses, one half of which (from mitral to granule cell) has an asymmetrical synaptic thickening associated with spheroidal vesicles, while the other half (from granule to mitral cell) has a symmetrical synaptic thickening and flattened vesicles. Qualitative observations, supported by preliminary quantitative measurements, suggest that it may be possible to divide both the spheroidal and flattened-vesicle types into two further varieties, on the basis of size, The smaller variety of spheroidal vesicles is found in most axon terminals, while the larger spheroidal vesicles are present in mitral cell dendrites and in some of the axon terminals. The flattened vesicles associated with symmetrical synapses which are oriented on to the granule cells are smaller than the spheroidal vesicles, but the flattened vesicles in the spines and gemmules of the granule cells are the same size or larger than the spheroidal vesicles. The division of flattened vesicles into two sizes is supported by statistical analysis of measurements of these vesicles, but because of difficulty in identifying the axon terminals with asymmetrical synapses there is no quantitative evidence for such a division of spheroidal vesicles. The asymmetrical synapses are found predominantly on spines, gemmules, and dendritic varicosities, although they are occasionally present on shafts of dendrites and on the cell somata. The symmetrical synapses are almost completely restricted to the shafts of the peripheral processes and the deep dendrites, and to the cell somata; only very rarely are synapses of this type found on spines, and then always in conjunction with an asymmetrical synapse.

scholarly journals Geophysical Factors as Crime Determinants

2021 ◽  
Vol 15 (1) ◽  
pp. 27-35
Author(s):  
Dmitriy Zhmurov ◽  
Sergey Tikhomirov
Keyword(s):  
Natural Disasters ◽  
Social Consequences ◽  
Routine Activity ◽  
General Strategy ◽  
Criminological Research ◽  
Negative Emotional State ◽  
Quantitative Characteristics ◽  
The Impact ◽  
Qualitative And Quantitative Characteristics

The problems of ensuring the safety of people during natural disasters and of mitigating their consequences have long been discussed at the highest levels. The currently adopted approach determines that the key task of every state is to develop a general strategy of predicting natural disasters, to organize cooperation on ensuring the safety of people and reducing material damage, and to reduce the dangerous anthropogenic impact on the environment as a cause of catastrophes. An important segment in the development of such programs is criminological research of crimes in the conditions of natural disasters. This article analyzes key concepts of the impact that natural disasters have on crime (therapeutic community, social disorganization, hypothesis of routine activity). It is concluded that the consequences of natural disasters have a criminologically meaningful effect on all spheres of public life. As a rule, such events lead to changes in both absolute and relative indices of crime, in its qualitative and quantitative characteristics. Key forms of criminal activities are analyzed and described, including: 1) vital, as a form of adapting and satisfying vital needs in the conditions of acute deficit of resources (food, clothes, medications, etc.); 2) affective, i.e. conditioned by a negative emotional state of people; 3) disinhibited, arising from the collapse of social control institutions, feelings of the absence of control and impunity for any actions; 4) situational, as an optimal form of behavior in the existing conditions, as a method of reaching some goals; 5) delayed, representing long-term social consequences of natural disasters.

scholarly journals Ultrasonido para la valoración del contenido gástrico: revisión sistemática de la literatura

2020 ◽  
Vol 49 (4) ◽  
pp. 493-503
Author(s):  
Darío Fernando Ortega Vallejo ◽  
Andrés Felipe Erazo Narvaez ◽  
León Santiago Díez Chamorro ◽  
Daniela Suárez Rodríguez ◽  
Jamer Armando Campo Sánchez ◽  
...  
Keyword(s):  
Systematic Review ◽  
Cochrane Library ◽  
Long Term Outcomes ◽  
Revisión Sistemática ◽  
Gastric Contents ◽  
Quantitative Characteristics ◽  
Different Populations ◽  
Qualitative And Quantitative Characteristics

Pneumonic aspiration of gastric contents is an important complication of anesthetic practice. : To determine the applicability of ultrasound for the assessment of the qualitative and quantitative characteristics of gastric contents. : A systematic review was carried out, based on a structured search of the literature published in the databases: Pubmed, EMBASE, SciELO, Cochrane Library, OVID and Google Scholar, from the foundation of these until December 2018 Boolean connectors were used to locate information from the terms: anesthesiology, ultrasonography, gastrointestinal Contents. The quality of the information was assessed using different tools according to each type of study. : We found 23 relevant studies for inclusion in the systematic review. The overall risk of bias was low. : Gastric ultrasound seems to correspond to a tool that is easy to perform at the patient’s bedside, but there is uncertainty about its applicability in uncontrolled settings, different from those applied in the studies described in this review. More research is needed with different populations and scenarios, in favor of establishing the behavior in these, of the variables that can be determined by ultrasound. The implications for clinical practice and long-term outcomes may have the measurements achieved by ultrasound are still uncertain.

The Termination of Centrifugal Fibres in the Glomerular Layer of the Olfactory Bulb

1972 ◽  
Vol 10 (3) ◽  
pp. 621-635
Author(s):  
A. J. PINCHING ◽  
T. P. S. POWELL
Keyword(s):  
Electron Microscope ◽  
Olfactory Bulb ◽  
Mitral Cell ◽  
Lateral Olfactory Tract ◽  
Anterior Olfactory Nucleus ◽  
Axon Terminals ◽  
Glomerular Layer ◽  
Olfactory Tract ◽  
Functional Implications

The termination of the centrifugal fibres running in the lateral olfactory tract to the glomerular layer of the rat olfactory bulb has been determined with the electron microscope; this has been done with material perfused at various times after section of the lateral olfactory tract, as well as after a combination of this lesion with the long-term degeneration of olfactory nerves. The axon terminals are sparse at the glomerular level, but undergo typical degenerative changes; they are distributed solely in the periglomerular region and intermediate zone. The most common post-synaptic profiles are the processes of periglomerular cells, but a few centrifugal fibres terminate on short-axon, tufted and mitral cell dendrites. Evidence is produced to suggest that the anterior olfactory nucleus does not project as far as the glomerular layer. The findings are discussed in relation to previous studies with normal material and silver degeneration methods on similar experimental material; the functional implications of the centrifugal pathways in the bulb are briefly discussed.

Long-Term Enhancement of Synchronized Oscillations by Adrenergic Receptor Activation in the Olfactory Bulb

2008 ◽  
Vol 99 (4) ◽  
pp. 2021-2025 ◽  
Author(s):  
David H. Gire ◽  
Nathan E. Schoppa
Keyword(s):  
Olfactory Bulb ◽  
Associative Learning ◽  
Field Potential ◽  
Gamma Oscillations ◽  
Olfactory Nerve ◽  
Receptor Activation ◽  
Cell Network ◽  
Functional Perspective ◽  
Gamma Frequency

The noradrenergic system is widely thought to be important for associative learning in the olfactory system through actions in the first processing structure, the main olfactory bulb (MOB). Here, we used extracellular local field potential (LFP) and patch-clamp recordings in rat MOB slices to examine norepinephrine (NE)-induced long-term changes in circuit properties that might underlie learning. During responses to patterned olfactory nerve stimulation mimicking the breathing cycle, NE induced a long-term increase in gamma frequency (30–70 Hz) synchronized oscillations. The enhancement persisted long after washout of NE (≤70 min), depended on the combined actions of NE and neuronal stimulation, and seemed to be caused by enhanced excitatory drive on the mitral/granule cell network that underlies rapid gamma oscillations. The last effect, increased excitation, was manifested as an increase in evoked long-lasting depolarizations (LLDs) in mitral cells. From a functional perspective, the observed long-term cellular and network changes could promote associative learning by amplifying odor-specific signals.

scholarly journals LINEAR AND WEIGHT GROWTH OF THE WALLEYE IN THE TEREK-CASPIAN FISHERY SUBDISTRICT

2021 ◽  
pp. 11-16
Author(s):  
Aminat Kamilovna ALIEVA ◽  
Botagoz Murasovna NASIBULINA ◽  
Akhma Saydbegovich ABDUSAMADOV ◽  
Ruslan Magomedovich BARKHALOV ◽  
Tatyana Fedorovna KUROCHKINA
Keyword(s):  
Average Length ◽  
Inland Waters ◽  
Habitat Conditions ◽  
The Caspian Sea ◽  
Hydrochemical Regime ◽  
Weight Growth ◽  
Stable Conditions ◽  
Quantitative Characteristics ◽  
Qualitative And Quantitative Characteristics

The article presents the linear and weight growth of the pikeperch in the coastal and inland waters of the Terek-Caspian fishery subdistrict. The dynamics of the linear and weight growth of the pikeperch on the Daghestan coast of the Caspian Sea and in the inland waters of Daghestan in the long-term aspect is shown. It was revealed that the average length and weight of the same-age pikeperch in different years are at a close level, which indicates stable conditions of living, feeding and food supply in the study period. The formation of the pikeperch populations in the Terek-Caspian region is influenced by the dynamic environmental conditions (sea level, hydrological and hydrochemical regime, water pollution). At the same time, the influence of habitat conditions is not critical and does not lead to significant changes in the qualitative and quantitative characteristics of the pikeperch and its forage objects in modern conditions.

Assessment of drugs increasing the reproductive function of cows of oocyte donors

2020 ◽  
pp. 122-126
Author(s):  
A. Plakhova ◽  
K. Plemyashov
Keyword(s):  
Maximum Concentration ◽  
Ultrasound Examination ◽  
Reproductive Function ◽  
Experimental Animals ◽  
Qualitative And Quantitative ◽  
Quantitative Characteristics ◽  
Oocyte Donors ◽  
Experimental Group ◽  
Qualitative And Quantitative Characteristics ◽  
Donor Cows

In these studies, a comprehensive assessment of the effect of the drugs «Carofertin» and «Hemobalance» on the reproductive function of oocyte donor cows was carried out. At the same time, the effect of these drugs on the biochemical parameters of blood serum, as well as on the concentration of progesterone, carotene in the experimental groups and the activity of the ovaries in the experimental animals was assessed. An increase in the activity of alkaline phosphatase in the first and third experimental groups was found, which amounted to 128.80 and 104.6 IU / L. There was also a decrease in the concentration of cholesterol in the experimental groups compared with the control. The maximum concentration of carotene was noted in the experimental group No. 1, which were injected with «Carofertin» subcutaneously, and in the experimental group No. 3, which were injected with «Carofertin» and «Hemobalance». The maximum concentration of progesterone was also noted in groups No. 3 and No. 1 and amounted to 21.98±3.03 and 17.01±9.68 nmol / l, respectively. In the course of ultrasound examination of the ovaries in experimental animals, a relationship was noted between the concentration of progesterone and the intensity of the blood supply of the corpus luteum on the ovaries in experimental animals. Subsequently, in one animal from each experimental group, oocytes were aspirated (OPU) twice with an interval of two weeks and their qualitative and quantitative characteristics were assessed. The maximum number of oocytes suitable for use was noted in the experimental group No. 3, which was injected with both study drugs.

Formation of work models ormation of work models of nursing staff of different levels

2020 ◽  
pp. 39-47
Author(s):  
Irina Muntyan
Keyword(s):  
Nursing Staff ◽  
Nursing Personnel ◽  
Methodological Basis ◽  
Qualitative And Quantitative ◽  
Quantitative Characteristics ◽  
Work Model ◽  
Different Levels ◽  
Qualitative And Quantitative Characteristics

The work model of a nurse includes 14 elements representing the qualitative and quantitative characteristics of the work. The analysis of these elements allowed us to form and offer work models for senior and rankand-file nurses. These models ensure selection, evaluation and placement of nursing personnel on a uniform methodological basis.

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