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Development Genes and Evolution Mar 2020Spiders are equipped with a large number of innervated cuticular specializations, which respond to various sensory stimuli. The physiological function of mechanosensory...
Spiders are equipped with a large number of innervated cuticular specializations, which respond to various sensory stimuli. The physiological function of mechanosensory organs has been analysed in great detail in some model spider species (e.g. Cupiennius salei); however, much less is known about the distribution and function of chemosensory organs. Furthermore, our knowledge on how the sense organ pattern develops on the spider appendages is limited. Here we analyse the development of the pattern and distribution of six different external mechano- and chemosensory organs in all postembryonic stages and in adult male and female spiders of the species Parasteatoda tepidariorum. We show that except for small mechanosensory setae, external sense organs appear in fixed positions on the pedipalps and first walking legs, arranged in longitudinal rows along the proximal-distal axis or in invariable positions relative to morphological landmarks (joints, distal tarsal tip). A comparison to other Entelegynae spiders shows that these features are conserved. We hope that this study lays the foundation for future molecular analysis to address the question how this conserved pattern is generated.
Topics: Animals; Extremities; Female; Femur; Male; Metatarsus; Microscopy, Electron, Scanning; Sense Organs; Sensilla; Spiders; Tibia
PubMed: 32036445
DOI: 10.1007/s00427-020-00655-8 -
Graefe's Archive For Clinical and... Oct 2023To explore whether topical antibiotic prophylaxis in patients scheduled for intravitreal injections achieves surface sterility in a greater proportion of subjects as... (Randomized Controlled Trial)
Randomized Controlled Trial
PURPOSE
To explore whether topical antibiotic prophylaxis in patients scheduled for intravitreal injections achieves surface sterility in a greater proportion of subjects as compared to povidone-iodine alone.
MATERIAL AND METHODS
A randomized, triple-blind clinical trial.
POPULATION
patients scheduled for intravitreal injections for maculopathy.
INCLUSION CRITERIA
any sex and race, age 18 years and above. Subjects were randomized into 4 groups: the first group applied chloramphenicol (CHLORAM), the second netilmicin (NETILM), the third a commercial ozonized antiseptic solution (OZONE), and the fourth applied no drops (CONTROL).
OUTCOME VARIABLE
percentage of non-sterile conjunctival swabs. Specimens were collected before and after the application of 5% povidone-iodine moments before the injection.
RESULTS
Ninety-eight subjects (33.7% females, 64.3% males), mean age: 70.2 ± 9.3 years (54-91). Before povidone-iodine, both the CHLORAM and NETILM group showed a lower percentage of non-sterile swabs (61.1% and 31.3% respectively), as compared to the OZONE (83.3%) and CONTROL (86.5%) groups (p < .04). However, this statistical difference was lost after the application of povidone-iodine for 3 min. Percentage of non-sterile swabs in each group after applying 5% povidone-iodine: CHLORAM 11.1%, NETILM 12.5%, CONTROL 15.4%, OZONE 25.0%. This was not statistically significant (p > .05).
CONCLUSIONS
Topical antibiotic prophylaxis with chloramphenicol or netilmicin drops decreases the bacterial load on the conjunctiva. However, after the application of povidone-iodine, all groups showed a significant reduction in the percentage of non-sterile swabs, and this value was comparable among all groups. For this reason, authors conclude that povidone-iodine alone is sufficient and prior topical antibiotic prophylaxis is not indicated.
Topics: Male; Female; Humans; Middle Aged; Aged; Adolescent; Povidone-Iodine; Antibiotic Prophylaxis; Anti-Bacterial Agents; Intravitreal Injections; Pilot Projects; Netilmicin; Endophthalmitis; Chloramphenicol; Anti-Infective Agents, Local; Conjunctiva
PubMed: 37199800
DOI: 10.1007/s00417-023-06113-1 -
BMC Biology Feb 2021Insects and other arthropods utilise external sensory structures for mechanosensory, olfactory, and gustatory reception. These sense organs have characteristic shapes...
Insects and other arthropods utilise external sensory structures for mechanosensory, olfactory, and gustatory reception. These sense organs have characteristic shapes related to their function, and in many cases are distributed in a fixed pattern so that they are identifiable individually. In Drosophila melanogaster, the identity of sense organs is regulated by specific combinations of transcription factors. In other arthropods, however, sense organ subtypes cannot be linked to the same code of gene expression. This raises the questions of how sense organ diversity has evolved and whether the principles underlying subtype identity in D. melanogaster are representative of other insects. Here, we provide evidence that such principles cannot be generalised, and suggest that sensory organ diversification followed the recruitment of sensory genes to distinct sensory organ specification mechanism. RESULTS: We analysed sense organ development in a nondipteran insect, the flour beetle Tribolium castaneum, by gene expression and RNA interference studies. We show that in contrast to D. melanogaster, T. castaneum sense organs cannot be categorised based on the expression or their requirement for individual or combinations of conserved sense organ transcription factors such as cut and pox neuro, or members of the Achaete-Scute (Tc ASH, Tc asense), Atonal (Tc atonal, Tc cato, Tc amos), and neurogenin families (Tc tap). Rather, our observations support an evolutionary scenario whereby these sensory genes are required for the specification of sense organ precursors and the development and differentiation of sensory cell types in diverse external sensilla which do not fall into specific morphological and functional classes. CONCLUSIONS: Based on our findings and past research, we present an evolutionary scenario suggesting that sense organ subtype identity has evolved by recruitment of a flexible sensory gene network to the different sense organ specification processes. A dominant role of these genes in subtype identity has evolved as a secondary effect of the function of these genes in individual or subsets of sense organs, probably modulated by positional cues.
Topics: Animals; Gene Expression; Larva; RNA Interference; Sense Organs; Tribolium
PubMed: 33546687
DOI: 10.1186/s12915-021-00948-y -
Journal of Integrative Neuroscience Jan 2024Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor symptoms such as tremors, rigidity, and bradykinesia. While the diagnosis of PD primarily... (Review)
Review
Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor symptoms such as tremors, rigidity, and bradykinesia. While the diagnosis of PD primarily relies on clinical assessments and neurological examination, there has been growing interest in exploring non-invasive imaging techniques to aid in early detection and monitoring of the disease. In recent years, retinal imaging has emerged as a promising tool for studying PD due to the close anatomical and functional similarities between the retina and the brain. Retinal imaging methods, such as spectral domain optical coherence tomography and optical coherence tomography angiography, enable non-intrusive visualization and measurement of retinal structures and blood vessels. These techniques hold the promise of capturing alterations in retinal structure and function that could potentially mirror the underlying pathological mechanisms in PD. This review article aims to provide an overview of the current understanding of retinal changes in PD and the potential utility of retinal imaging as a diagnostic and monitoring tool.
Topics: Humans; Parkinson Disease; Retina; Tomography, Optical Coherence; Brain
PubMed: 38287853
DOI: 10.31083/j.jin2301023 -
Aerospace Medicine and Human Performance Aug 2018Orientation in a 3-dimensional environment increases demands on the vestibular system. The anterior, lateral, and posterior semicircular canals sense pitch, roll, and... (Comparative Study)
Comparative Study Review
INTRODUCTION
Orientation in a 3-dimensional environment increases demands on the vestibular system. The anterior, lateral, and posterior semicircular canals sense pitch, roll, and yaw acceleration, respectively. The macular end organs sense linear acceleration and provide gravity reference. Creatures that evolved to fly (birds) share the same sensory systems and probably the same limitations as creatures that did not evolve to fly. However, bird semicircular canals have been noted for their large size relative to body mass since 1907.
METHODS
A brief literature review was conducted regarding the morphological structure of the vestibular systems in birds, and their evolutionary and functional significance as compared to that in humans.
RESULTS
For any given body mass, qualitatively more "agile" species have semicircular canals with larger radius of curvature. Specifically, the anterior and lateral canals were found to be preferentially larger than those of nonavian theropods and humans. Avian canals rarely approach circularity and all three canals typically undergo torsional excursions out of their respective planes.
DISCUSSION
Increase in the length of the semicircular canal is associated with greater sensitivity to rotational stimuli. Highly maneuverable birds of prey have the largest overall canal dimensions relative to body mass, most plausibly to match the rapid body rotations that characterize variable speed maneuvering during pursuit. By comparison, the semicircular canals in humans are relatively smaller and lack the adaptive morphological asymmetry in agile flying species. This teleological symmetry may present another inherent but less understood vestibular limitation during aerobatic maneuvers, which could lead to spatial disorientation.Cheung B, Ercoline W. Semicircular canal size and shape influence on disorientation. Aerosp Med Hum Perform. 2018; 89(8):744-748.
Topics: Animals; Biological Evolution; Birds; Confusion; Flight, Animal; Humans; Pilots; Semicircular Canals; Space Flight; Vestibule, Labyrinth
PubMed: 30020060
DOI: 10.3357/AMHP.5104.2018 -
Seminars in Ophthalmology 2017Oculodermal melanocytosis (ODM) is a rare disease, which is characterized by hyperpigmentation of facial skin and several parts of the eye, such as the sclera,... (Review)
Review
Oculodermal melanocytosis (ODM) is a rare disease, which is characterized by hyperpigmentation of facial skin and several parts of the eye, such as the sclera, conjunctiva, cornea, iris, ciliary body, and choroid. The condition usually affects the Asian female population. The most typical presenting ocular sign is iris heterocromia. Iris hyperpigmentation may be associated with iris mammillations, which are dome-shaped protuberations of the iris surface. They are linked to a higher risk of malignant transformation when present in patients with ODM. Glaucoma is a complication of ODM and is caused by angle abnormalities or mechanical occlusion by melanocytes in an open irido-corneal angle. Choroidal and ciliary body melanoma have a higher incidence in this condition characterized by melanocytosis. Patients presenting ODM should undergo routine ophthalmological examination in order to carefully monitor for glaucoma and melanoma.
Topics: Choroid; Ciliary Body; Humans; Melanocytes; Melanoma; Melanosis; Skin Neoplasms; Uveal Neoplasms
PubMed: 27083007
DOI: 10.3109/08820538.2015.1118133 -
International Journal of Molecular... Feb 2023Parkinson's disease (PD) is a neurodegenerative condition characterized by the progressive deterioration of dopaminergic neurons in the central and peripheral autonomous... (Review)
Review
Parkinson's disease (PD) is a neurodegenerative condition characterized by the progressive deterioration of dopaminergic neurons in the central and peripheral autonomous system and the intraneuronal cytoplasmic accumulation of misfolded α-synuclein. The clinical features are the classic triad of tremor, rigidity, and bradykinesia and a set of non-motor symptoms, including visual deficits. The latter seems to arise years before the onset of motor symptoms and reflects the course of brain disease. The retina, by virtue of its similarity to brain tissue, is an excellent site for the analysis of the known histopathological changes of PD that occur in the brain. Numerous studies conducted on animal and human models of PD have shown the presence of α-synuclein in retinal tissue. Spectral-domain optical coherence tomography (SD-OCT) could be a technique that enables the study of these retinal alterations in vivo. The objective of this review is to describe recent evidence on the accumulation of native or modified α-synuclein in the human retina of patients with PD and its effects on the retinal tissue evaluated through SD-OCT.
Topics: Animals; Humans; alpha-Synuclein; Brain; Parkinson Disease; Retina; Tremor
PubMed: 36901822
DOI: 10.3390/ijms24054391 -
Advanced Biosystems Apr 2019Keratan sulfate (KS) is a functional electrosensory and neuro-instructive molecule. Recent studies have identified novel low sulfation KS in auditory and sensory tissues... (Review)
Review
Keratan sulfate (KS) is a functional electrosensory and neuro-instructive molecule. Recent studies have identified novel low sulfation KS in auditory and sensory tissues such as the tectorial membrane of the organ of Corti and the Ampullae of Lorenzini in elasmobranch fish. These are extremely sensitive proton gradient detection systems that send signals to neural interfaces to facilitate audition and electrolocation. High and low sulfation KS have differential functional roles in song learning in the immature male zebra song-finch with high charge density KS in song nuclei promoting brain development and cognitive learning. The conductive properties of KS are relevant to the excitable neural phenotype. High sulfation KS interacts with a large number of guidance and neuroregulatory proteins. The KS proteoglycan microtubule associated protein-1B (MAP1B) stabilizes actin and tubulin cytoskeletal development during neuritogenesis. A second 12 span transmembrane synaptic vesicle associated KS proteoglycan (SV2) provides a smart gel storage matrix for the storage of neurotransmitters. MAP1B and SV2 have prominent roles to play in neuroregulation. Aggrecan and phosphacan have roles in perineuronal net formation and in neuroregulation. A greater understanding of the biology of KS may be insightful as to how neural repair might be improved.
Topics: Animals; Electric Conductivity; Electrophysiological Phenomena; Humans; Keratan Sulfate; Membrane Glycoproteins; Neurons; Proteoglycans; Sense Organs; Sensory Receptor Cells
PubMed: 32627425
DOI: 10.1002/adbi.201800327 -
Overview of the retina and imaging in patients with severe acute respiratory syndrome coronavirus 2.International Ophthalmology Nov 2022The role of the human eye in severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) is still under investigation. The pathophysiology of the ocular findings is... (Review)
Review
INTRODUCTION
The role of the human eye in severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) is still under investigation. The pathophysiology of the ocular findings is arduous when dealing with critically ill Covid-19 patients with comorbidities. Multiorgan involvement and the effects of inflammation, infection and systemic treatment on the retina are complex, and comparison of studies is difficult. Most studies in human patients have investigated the anterior segment, whereas few reports deal with the posterior segment of the eye. The present review aims to evaluate the retinal manifestations and imaging features in COVID-19 patients.
METHODS
Studies on the retinal manifestations and retinal imaging in COVID-19 patients published through June 2021 were reviewed. We included cross-sectional and case-control studies, case series, case reports and correspondence in the analysis.
RESULTS
Flame-shaped hemorrhages, cotton wool spots, augmented diameter and tortuosity of retinal vessels were found on funduscopic examination. Peripapillary, macular retinal nerve fiber layer and ganglion cell layer thickness alterations were reported on spectral domain optical coherence tomography. Reduced vessel density of the superficial and deep retinal capillary plexus on optical coherence tomography angiography was reported.
CONCLUSIONS
Retinal complications may arise in COVID-19 patients. Although no consensus on presentation is currently available, retinal funduscopy and imaging has shown neuronal and vascular alterations. Systemic neurological complications and microangiopathy are associated with SARS-COV-2; thus, as the retina has a neuronal and vascular component, funduscopy and retinal imaging on COVID-19 patients can provide further insight to SARS-COV-2 disease and the follow-up of patients.
Topics: Humans; SARS-CoV-2; Fluorescein Angiography; COVID-19; Cross-Sectional Studies; Retina; Retinal Vessels; Tomography, Optical Coherence
PubMed: 35546380
DOI: 10.1007/s10792-022-02338-x -
Journal of Cellular Physiology Sep 2016The trabecular meshwork (TM) plays an important role in high-tension glaucomas. Indeed, the TM is a true organ, through which the aqueous humor flows from the anterior... (Review)
Review
The trabecular meshwork (TM) plays an important role in high-tension glaucomas. Indeed, the TM is a true organ, through which the aqueous humor flows from the anterior chamber to Schlemm's canal (SC). Until recently, the TM, which is constituted by endothelial-like cells, was described as a kind of passive filter. In reality, it is much more. The cells delineating the structures of the collagen framework of the TM are endowed with a cytoskeleton, and are thus able to change their shape. These cells also have the ability to secrete the extracellular matrix, which expresses proteins and cytokines, and are capable of phagocytosis and autophagy. The cytoskeleton is attached to the nuclear membrane and can, in millionths of a second, send signals to the nucleus in order to alter the expression of genes in an attempt to adapt to biomechanical insult. Oxidative stress, as happens in aging, has a deleterious effect on the TM, leading eventually to cell decay, tissue malfunction, subclinical inflammation, changes in the extracellular matrix and cytoskeleton, altered motility, reduced outflow facility, and (ultimately) increased IOP. TM failure is the most relevant factor in the cascade of events triggering apoptosis in the inner retinal layers, including ganglion cells. J. Cell. Physiol. 231: 1876-1893, 2016. © 2016 Wiley Periodicals, Inc.
Topics: Animals; Aqueous Humor; Cytoskeleton; Extracellular Matrix; Glaucoma; Humans; Oxidative Stress; Trabecular Meshwork
PubMed: 26754581
DOI: 10.1002/jcp.25305