scholarly journals Phenotypic plasticity associated to environmental hypoxia in the neotropical serrasalmid Piaractus mesopotamicus (Holmberg, 1887) (Characiformes: Serrasalmidae)

2016 ◽  
Vol 14 (2) ◽  
Author(s):  
María Alejandra Fernández-Osuna ◽  
Pablo Augusto Scarabotti
Keyword(s):  
Morphological Changes ◽  
Experimental Studies ◽  
South American ◽  
Threshold Values ◽  
Functional Link ◽  
Lower Lip ◽  
Piaractus Mesopotamicus ◽  
Valve Development ◽  
Similar Threshold ◽  
Distal Border

ABSTRACT Many South American characid fishes develop reversible dermal protuberances in the jaws to optimize aquatic surface respiration (ASR) during hypoxia. To date, basic aspects of this adaptation remain unknown, mainly due to the scarcity of experimental studies. In laboratory experiments, we determined time necessary for the complete formation and reversion of these structures in Piaractus mesopotamicus , and studied comparatively behavioral, morphological, and respiratory responses along gradients of dissolved oxygen (DO) concentration. Morphological changes during hypoxia consisted in dermal protuberances of lower lip, anterior border of maxillary and distal border of opercular valve, increasing the known number of structures modified. These structures developed completely in less than 6 hours and reversed in less than 3 hours. Most of observed traits showed a logistic response curve with threshold DO values between 0.90 and 2.70 mgL-1. Respiratory frequency and opercular valve development showed similar threshold values above the level of tolerance of DO, whereas ASR and dermal protuberances of the jaws showed threshold values below this level. This observation supports the functional link between these groups of behavioral and morphological traits. This study demonstrates that this species is able to modify reversibly portions of the respiratory system to optimize responses to hypoxia.

scholarly journals The Neuroinflammatory Role of Pericytes in Epilepsy

Biomedicines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 759
Author(s):  
Gaku Yamanaka ◽  
Fuyuko Takata ◽  
Yasufumi Kataoka ◽  
Kanako Kanou ◽  
Shinichiro Morichi ◽  
...  
Keyword(s):  
Proinflammatory Cytokines ◽  
Current Knowledge ◽  
Morphological Changes ◽  
Cell Damage ◽  
Neurovascular Unit ◽  
Experimental Studies ◽  
Intractable Epilepsy ◽  
In Vivo Studies

Pericytes are a component of the blood–brain barrier (BBB) neurovascular unit, in which they play a crucial role in BBB integrity and are also implicated in neuroinflammation. The association between pericytes, BBB dysfunction, and the pathophysiology of epilepsy has been investigated, and links between epilepsy and pericytes have been identified. Here, we review current knowledge about the role of pericytes in epilepsy. Clinical evidence has shown an accumulation of pericytes with altered morphology in the cerebral vascular territories of patients with intractable epilepsy. In vitro, proinflammatory cytokines, including IL-1β, TNFα, and IL-6, cause morphological changes in human-derived pericytes, where IL-6 leads to cell damage. Experimental studies using epileptic animal models have shown that cerebrovascular pericytes undergo redistribution and remodeling, potentially contributing to BBB permeability. These series of pericyte-related modifications are promoted by proinflammatory cytokines, of which the most pronounced alterations are caused by IL-1β, a cytokine involved in the pathogenesis of epilepsy. Furthermore, the pericyte-glial scarring process in leaky capillaries was detected in the hippocampus during seizure progression. In addition, pericytes respond more sensitively to proinflammatory cytokines than microglia and can also activate microglia. Thus, pericytes may function as sensors of the inflammatory response. Finally, both in vitro and in vivo studies have highlighted the potential of pericytes as a therapeutic target for seizure disorders.

scholarly journals MODERN CONCEPTION AS TO THE FUNCTIONAL MORPHOLOGY OF THE OLFACTORY SYSTEM AND ITS CHANGES UNDER THE INFLUENCE OF SOME EXOGENOUS POLLUTANTS

2019 ◽  
Vol 23 (3-4) ◽  
pp. 37-40
Author(s):  
A.D. Shkodina ◽  
R.M. Hrinko ◽  
I.I. Starchenko
Keyword(s):  
Environmental Factors ◽  
Olfactory Epithelium ◽  
Functional Organization ◽  
Morphological Changes ◽  
Human Life ◽  
Experimental Studies ◽  
Experimental Models ◽  
Functional Changes ◽  
Olfactory Analyzer ◽  
Long Time

The interaction between a body and an environment provides the main aspects of human life. The study of the functional structure of the olfactory analyzer plays an important role both in clinical and in experimental studies, but the question of its features in humans needs detailed research. The paper presents the modern data of the structural and functional organization of the olfactory analyzer. Particular attention is paid to the structural organization of olfactory bulbs as most complicated and least studied component of the olfactory analyzer. The morphological and functional changes of the olfactory analyzer are developing in some diseases and in action of adverse environmental factors are described while the accentuation is placed on the differences of the mechanism in the pathogenesis of damage to the olfactory analyzer, depending on the nature of the influence of pathogenic factors. In this way as the result of short-term intense effects of the pollutant, irreversible atrophic changes are primarily affected to the olfactory epithelium, thus, to some extent, preventing the spread of the toxin to other analyzer structures. Conversely, a long-term exposure to low doses usually retains the functional activity of the olfactory epithelium, while harmful substances penetrate the central unit of the olfactory analyzer. In such cases, the olfactory dysfunction can be diagnosed after a long time after the start of the cohort with certain pollutants. Currently, studies of the influence of exogenous toxins on various parts of the olfactory analyzer on animal experimental models are quite active. At the same time, the issue of functional and morphological changes in various structural components of the human olfactory analyzer under the influence of negative environmental factors remains poorly understood and requires further morphological and biochemical studies, in order to be able to further develop effective therapeutic and prophylactic means.

Development of the ventricles and valves

ESC CardioMed ◽  
2018 ◽  
pp. 44-49
Author(s):  
José M. Pérez-Pomares ◽  
José L. de la Pompa
Keyword(s):  
Congenital Heart Disease ◽  
Heart Disease ◽  
Congenital Heart ◽  
Cardiac Development ◽  
Experimental Studies ◽  
Heart Tube ◽  
Cellular Mechanisms ◽  
Valve Development ◽  
Tissue Interactions ◽  
The Right

The heart is the first functional organ of the vertebrate embryo, beginning to beat at around 4 weeks of gestation in humans. Tissue interactions orchestrate the complex patterning, proliferation, and differentiation processes that transform the embryonic cardiac primordium into the adult heart. During heart embryogenesis, cardiac mesoderm progenitor cells originate bilaterally during gastrulation and move rostrally to form the primitive heart tube, which will then loop towards the right and initiate septation to give rise to the mature four-chambered heart. Experimental studies in animal models have revealed the crucial role that a number of highly conserved signalling pathways, involving active molecular cross-talk between adjacent tissues, play in cardiac development, and how the alterations in these signalling mechanisms may cause congenital heart disease affecting the neonate or adult. Here, we describe briefly the knowledge gained on the molecular and cellular mechanisms underlying cardiac chamber and valve development and its implication in disease. This knowledge will ultimately facilitate the design of diagnostic and therapeutic strategies to treat congenital heart disease.

Brasilomma gen. nov., a new prodidomid genus from Brazil (Araneae, Prodidomidae)

Zootaxa ◽  
2012 ◽  
Vol 3572 (1) ◽  
pp. 23 ◽  
Author(s):  
ANTONIO DOMINGOS BRESCOVIT ◽  
RODRIGO LOPES FERREIRA ◽  
MARCONI SOUZA SILVA ◽  
CRISTINA ANNE RHEIMS
Keyword(s):  
Natural History ◽  
The State ◽  
South American ◽  
Distal Border

The genus Brasilomma gen. nov. is described to include B. enigmatica sp. nov. collected in three caves from the state ofMinas Gerais, Brazil. This genus can be distinguished from the remaining South American Prodidomidae by the malepalps with large triangular projection, covering the base of the embolus, the distal border of the tegulum projected overthe base of the conductor and median apophysis and by the female epigynum with blind, posterior atrium and anteriorlywidened copulation ducts arising from an internal, mushroom-shaped plate. In addition, aspects of the species natural history are described.

scholarly journals Oxygenation properties and isoform diversity of snake hemoglobins

2015 ◽  
Vol 309 (9) ◽  
pp. R1178-R1191 ◽  
Author(s):  
Jay F. Storz ◽  
Chandrasekhar Natarajan ◽  
Hideaki Moriyama ◽  
Federico G. Hoffmann ◽  
Tobias Wang ◽  
...  
Keyword(s):  
Quaternary Structure ◽  
Experimental Studies ◽  
Integrated Analysis ◽  
South American ◽  
Globin Genes ◽  
Isoform Diversity ◽  
Structural And Functional Properties ◽  
Python Molurus ◽  
Crotalus Durissus ◽  
Allosteric Properties

Available data suggest that snake hemoglobins (Hbs) are characterized by a combination of unusual structural and functional properties relative to the Hbs of other amniote vertebrates, including oxygenation-linked tetramer-dimer dissociation. However, standardized comparative data are lacking for snake Hbs, and the Hb isoform composition of snake red blood cells has not been systematically characterized. Here we present the results of an integrated analysis of snake Hbs and the underlying α- and β-type globin genes to characterize 1) Hb isoform composition of definitive erythrocytes, and 2) the oxygenation properties of isolated isoforms as well as composite hemolysates. We used species from three families as subjects for experimental studies of Hb function: South American rattlesnake, Crotalus durissus (Viperidae); Indian python, Python molurus (Pythonidae); and yellow-bellied sea snake, Pelamis platura (Elapidae). We analyzed allosteric properties of snake Hbs in terms of the Monod-Wyman-Changeux model and Adair four-step thermodynamic model. Hbs from each of the three species exhibited high intrinsic O2 affinities, low cooperativities, small Bohr factors in the absence of phosphates, and high sensitivities to ATP. Oxygenation properties of the snake Hbs could be explained entirely by allosteric transitions in the quaternary structure of intact tetramers, suggesting that ligation-dependent dissociation of Hb tetramers into αβ-dimers is not a universal feature of snake Hbs. Surprisingly, the major Hb isoform of the South American rattlesnake is homologous to the minor HbD of other amniotes and, contrary to the pattern of Hb isoform differentiation in birds and turtles, exhibits a lower O2 affinity than the HbA isoform.

Experimental Studies of Glass Reinforced Aluminum (GLARE) Bolted Joint

2012 ◽  
Vol 217-219 ◽  
pp. 124-129
Author(s):  
Ji Feng Zhang ◽  
Zi Zhen Cao ◽  
Yong Gang Xie
Keyword(s):  
Impact Resistance ◽  
Experimental Studies ◽  
High Strength ◽  
Geometric Parameters ◽  
Experimental Program ◽  
Bolted Joint ◽  
Threshold Values ◽  
Tightening Torque ◽  
High Fatigue ◽  
Ply Orientation

GLARE laminates with outstanding impact resistance, high fatigue resistance and a number of excellent performances are combined by ductile aluminum layers and high strength FRP layers. An experimental program was conducted to estimate the influence of geometric parameters, ply orientation and tightening torque on the performances of GLARE bolted joint. The study showed that the parameters of GLARE bolted joint have intrinsic properties of metal bolted joint and composite bolted joint. The design threshold values including of geometric parameters, ply orientation and tightening torque were given.

scholarly journals Evaluation of histological changes in peri-implant bone tissue after ultrasound application at early healing stages

2018 ◽  
pp. 38-42 ◽  
Author(s):  
S.P. Rubnikovich ◽  
I.S. Khomich
Keyword(s):  
Bone Tissue ◽  
Dental Implants ◽  
Morphological Changes ◽  
Experimental Studies ◽  
Low Frequency ◽  
Control Group ◽  
Pulsed Ultrasound ◽  
Low Intensity Pulsed Ultrasound ◽  
Low Intensity ◽  
Dental Implantation

The aim was to study the nature of the morphological changes over time in the bone tissue around the implants under the influence of low-intensity pulsed ultrasound in the experiment. Materials and methods. Experimental studies were carried out on rabbits of the chinchilla breed, with dental implants installed in the tibia – two experimental groups with ultrasound and one control group. The animals were withdrawn from the experiment at 1, 2, 4 and 8 weeks and histological examination of the sections of peri-implant tissues was carried out. Results. The processes of osseointegration of dental implants in all groups of animals occurred without disrupting the normal process sequence. In the early stages granulation tissue is formed, later it is replaced by fibrous-reticular and coarse-fibrous bone tissue, and at the end – by a more mature lamellar bone tissue. However, the timing and degree of maturation of bone tissue, as well as osseointegration of implants in groups using low-frequency low-intensity pulsed ultrasound and without it differed significantly. The study showed that ultrasound exposure to implants and surrounding tissues induces osteoreparation processes, stimulating neoangiogenesis in granulation and newly formed bone tissue. Conclusion. Application of ultrasound to implants and subsequent application to the peri-implant tissues during and after dental implantation promotes the formation of bone tissue, identical by the histostructure to the maternal bone.

scholarly journals Morphological changes in the tissues of the knee joints of rats in carrageenan-induced experimental arthritis

2021 ◽  
pp. 12-17
Author(s):  
O. V. Pelypenko
Keyword(s):  
Synovial Membrane ◽  
Morphological Changes ◽  
Intraperitoneal Administration ◽  
Experimental Studies ◽  
Morphological Structure ◽  
Cartilage Tissue ◽  
Laboratory Animals ◽  
Functional Layer ◽  
Morphological Studies ◽  
And Cartilage

Every fifth inhabitant of the earth has been diagnosed with osteoarthritis of various etiologies. Morphological studies of arthritis provide a theoretical basis for creating optimal treatments for this pathology. Given the polyetiological nature of the disease, the choice of the optimal experimental model, which would be as close as possible to the real conditions of inflammatory process reproduction, is the topical issue. The purpose of the study was to confirm the pathological reaction of the joint tissues of laboratory animals in response to intraperitoneal administration of ƛ-carrageenan. The study was performed on 50 white Wistar rats males aged 12 weeks, weighing 130-150 g. The animals were euthanized by an overdose of anaesthesia according to the terms of the study (1 - 30 days). Fragments of the distal metaepiphyses of the femur and proximal metaepiphyses of the tibia were used for histological examination. Staining of sections obtained on the microtome was performed with haematoxylin, eosin, and Van Gieson`s stain. From the first day of the experimental study, a corresponding reaction of the joint tissues was being observed. Particularly pronounced were the changes in the synovial membrane in the form of oedema of the villi accompanied by an increased filling of blood vessels with foci of thrombosis. Gradually, up to 5 days in the synovial membrane, proliferative changes took place with a clear definition of the multilineage of the integumentary layer, vascular reaction with a tendency to thrombosis, in some places necrosis of synoviocytes was observed, but relative integrity of the morphological structure was still provided by protective barriers of bone and cartilage. On the 7th day pronounced resorption of both bone and cartilage tissue occurred, tissue structure became disorganized and functional layer became thin, accompanied by massive intracellular lysis. The process of synoviocytes necrobiosis with fatty degeneration spread. The histological picture of 10 days is characterized by generalized destruction of bone beams; the destroyed cartilage was replaced by granulation tissue with the presence of cavities. Massive foci of lymphocytic infiltration were observed in the synovial membrane. On the 14th day, a fragmentation of cartilage happened, most of the bone beams (trabeculae) were destroyed. After 3 weeks the morphological picture of cartilage tissue was determined by the appearance in the lacunae of viable cells, the number of which was close to normal. Bone beams were restored, although they remained thin. In a synovial membrane, the hyperplasia of apical departments of villi, leukocytes infiltration, disorganization of connective tissue, and separate vascular disturbances remained. 30 days of the experiment were characterized by a relative recovery of structural relationships to normal. The obtained data confirm the feasibility of using carrageenan in experimental studies of osteoarthritis.

scholarly journals Morphological changes of Sertoli cells during the male reproductive cycle of the teleost Piaractus mesopotamicus (Holmberg, 1887)

2005 ◽  
Vol 65 (2) ◽  
pp. 241-249 ◽  
Author(s):  
C. Cruz-Landim ◽  
F. C. Abdalla ◽  
M. A. Cruz-Höfling
Keyword(s):  
Germ Cell ◽  
Sertoli Cell ◽  
Reproductive Cycle ◽  
Sertoli Cells ◽  
Morphological Changes ◽  
Cell Development ◽  
Cell Maturation ◽  
Ultrastructural Changes ◽  
Piaractus Mesopotamicus

An investigation of the histological and ultrastructural changes of Sertoli cells during the male reproductive cycle in Piaractus mesopotamicus was made. The results showed that the Sertoli cell development is closely related with germ cell maturation. Therefore, these cells may have some role in germ cell maturation during the reproductive cycle of this species, whether in forming a tissue framework for the developing spermatogenic cysts, aiding in testes reorganization for a new reproductive cycle, in addition to other possible functions discussed in the text.

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