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Fluids and Barriers of the CNS Jan 2023Detecting changes in pulsatile cerebrospinal fluid (CSF) flow may assist clinical management decisions, but spinal CSF flow is relatively understudied. Traumatic spinal...
BACKGROUND
Detecting changes in pulsatile cerebrospinal fluid (CSF) flow may assist clinical management decisions, but spinal CSF flow is relatively understudied. Traumatic spinal cord injuries (SCI) often cause spinal cord swelling and subarachnoid space (SAS) obstruction, potentially causing pulsatile CSF flow changes. Pigs are emerging as a favoured large animal SCI model; therefore, the aim of this study was to characterise CSF flow along the healthy pig spine.
METHODS
Phase-contrast magnetic resonance images (PC-MRI), retrospectively cardiac gated, were acquired for fourteen laterally recumbent, anaesthetised and ventilated, female domestic pigs (22-29 kg). Axial images were obtained at C2/C3, T8/T9, T11/T12 and L1/L2. Dorsal and ventral SAS regions of interest (ROI) were manually segmented. CSF flow and velocity were determined throughout a cardiac cycle. Linear mixed-effects models, with post-hoc comparisons, were used to identify differences in peak systolic/diastolic flow, and maximum velocity (cranial/caudal), across spinal levels and dorsal/ventral SAS. Velocity wave speed from C2/C3 to L1/L2 was calculated.
RESULTS
PC-MRI data were obtained for 11/14 animals. Pulsatile CSF flow was observed at all spinal levels. Peak systolic flow was greater at C2/C3 (dorsal: - 0.32 ± 0.14 mL/s, ventral: - 0.15 ± 0.13 mL/s) than T8/T9 dorsally (- 0.04 ± 0.03 mL/s; p < 0.001), but not different ventrally (- 0.08 ± 0.08 mL/s; p = 0.275), and no difference between thoracolumbar levels (p > 0.05). Peak diastolic flow was greater at C2/C3 (0.29 ± 0.08 mL/s) compared to T8/T9 (0.03 ± 0.03 mL/s, p < 0.001) dorsally, but not different ventrally (p = 1.000). Cranial and caudal maximum velocity at C2/C3 were greater than thoracolumbar levels dorsally (p < 0.001), and T8/T9 and L1/L2 ventrally (p = 0.022). Diastolic velocity wave speed was 1.41 ± 0.39 m/s dorsally and 1.22 ± 0.21 m/s ventrally, and systolic velocity wave speed was 1.02 ± 0.25 m/s dorsally and 0.91 ± 0.22 m/s ventrally.
CONCLUSIONS
In anaesthetised and ventilated domestic pigs, spinal CSF has lower pulsatile flow and slower velocity wave propagation, compared to humans. This study provides baseline CSF flow at spinal levels relevant for future SCI research in this animal model.
Topics: Humans; Female; Swine; Animals; Retrospective Studies; Magnetic Resonance Imaging; Cerebrospinal Fluid Pressure; Spinal Cord; Sus scrofa; Cerebrospinal Fluid
PubMed: 36653870
DOI: 10.1186/s12987-022-00401-4 -
Journal of Wrist Surgery Sep 2018This study aims to evaluate the long-term complications, results, and patient satisfaction rates of a dorsally approached ulnar shortening osteotomy for ulnar...
This study aims to evaluate the long-term complications, results, and patient satisfaction rates of a dorsally approached ulnar shortening osteotomy for ulnar impaction syndrome. A retrospective chart review of 20 patients was performed. Primary outcomes of interest were subjective, measured using the Patient-Rated Wrist Evaluation (PRWE) score, Disability of the Arm, Shoulder, and Hand (DASH) score, and the third questionnaire about patient satisfaction, composed by the authors. Secondary outcomes included hardware removal due to irritation and other complications. Mean postoperative functional score of PRWE was 28 (standard deviation [SD], 30) and DASH 20 (SD, 26), respectively. Fifteen patients were satisfied with the operation. Removal of hardware was noted in six patients. In one patient plate breakage occurred. Similar postoperative functional scores and complications were seen in patients undergoing an ulnar shortening osteotomy with a dorsally placed plate for ulnar impaction syndrome, compared with other plate placement localizations. The incidence of plate removal is also comparable to previously described results. As the dorsally placed plate and freehand technique, are relatively easy, we feel that it has a place in the treatment of ulnar impaction syndrome. Level IV, retrospective cohort study.
PubMed: 30302301
DOI: 10.1055/s-0037-1608636 -
Frontiers in Neural Circuits 2023The cochlear nucleus (CN) is often regarded as the gateway to the central auditory system because it initiates all ascending pathways. The CN consists of dorsal and...
The cochlear nucleus (CN) is often regarded as the gateway to the central auditory system because it initiates all ascending pathways. The CN consists of dorsal and ventral divisions (DCN and VCN, respectively), and whereas the DCN functions in the analysis of spectral cues, circuitry in VCN is part of the pathway focused on processing binaural information necessary for sound localization in horizontal plane. Both structures project to the inferior colliculus (IC), which serves as a hub for the auditory system because pathways ascending to the forebrain and descending from the cerebral cortex converge there to integrate auditory, motor, and other sensory information. DCN and VCN terminations in the IC are thought to overlap but given the differences in VCN and DCN architecture, neuronal properties, and functions in behavior, we aimed to investigate the pattern of CN connections in the IC in more detail. This study used electrophysiological recordings to establish the frequency sensitivity at the site of the anterograde dye injection for the VCN and DCN of the CBA/CaH mouse. We examined their contralateral projections that terminate in the IC. The VCN projections form a topographic sheet in the central nucleus (CNIC). The DCN projections form a tripartite set of laminar sheets; the lamina in the CNIC extends into the dorsal cortex (DC), whereas the sheets to the lateral cortex (LC) and ventrolateral cortex (VLC) are obliquely angled away. These fields in the IC are topographic with low frequencies situated dorsally and progressively higher frequencies lying more ventrally and/or laterally; the laminae nestle into the underlying higher frequency fields. The DCN projections are complementary to the somatosensory modules of layer II of the LC but both auditory and spinal trigeminal terminations converge in the VLC. While there remains much to be learned about these circuits, these new data on auditory circuits can be considered in the context of multimodal networks that facilitate auditory stream segregation, signal processing, and species survival.
Topics: Mice; Animals; Inferior Colliculi; Cochlear Nucleus; Auditory Pathways; Mice, Inbred CBA; Neurons
PubMed: 37554670
DOI: 10.3389/fncir.2023.1229746 -
Clinical Anatomy (New York, N.Y.) Jul 2019In this article, we provide a comprehensive overview of multiple facets in the puzzling genesis of symmetrical conjoined twins. The etiopathogenesis of conjoined twins... (Review)
Review
In this article, we provide a comprehensive overview of multiple facets in the puzzling genesis of symmetrical conjoined twins. The etiopathogenesis of conjoined twins remains matter for ongoing debate and is currently cited-in virtually every paper on conjoined twins-as partial fission or secondary fusion. Both theories could potentially be extrapolated from embryological adjustments exclusively seen in conjoined twins. Adoption of these, seemingly factual, theoretical proposals has (unconsciously) resulted in crystallized patterns of verbal and graphic representations concerning the enigmatic genesis of conjoined twins. Critical evaluation on their plausibility and solidity remains however largely absent. As it appears, both the fission and fusion theories cannot be applied to the full range of conjunction possibilities and thus remain matter for persistent inconclusiveness. We propose that initial duplication of axially located morphogenetic potent primordia could be the initiating factor in the genesis of ventrally, laterally, and caudally conjoined twins. The mutual position of two primordia results in neo-axial orientation and/or interaction aplasia. Both these embryological adjustments result in conjunction patterns that may seemingly appear as being caused by fission or fusion. However, as we will substantiate, neither fission nor fusion are the cause of most conjoined twinning types; rather what is interpreted as fission or fusion is actually the result of the twinning process itself. Furthermore, we will discuss the currently held views on the origin of conjoined twins and its commonly assumed etiological correlation with monozygotic twinning. Finally, considerations are presented which indicate that the dorsal conjunction group is etiologically and pathogenetically different from other symmetric conjoined twins. This leads us to propose that dorsally united twins could actually be caused by secondary fusion of two initially separate monozygotic twins. An additional reason for the ongoing etiopathogenetic debate on the genesis of conjoined twins is because different types of conjoined twins are classically placed in one overarching receptacle, which has hindered the quest for answers. Clin. Anat. 32:722-741, 2019. © 2019 Wiley Periodicals, Inc.
Topics: Animals; Female; Humans; Male; Pregnancy; Twins, Conjoined
PubMed: 31001856
DOI: 10.1002/ca.23387 -
The Journal of Neuroscience : the... Jul 2015The pulvinar is the largest nucleus in the primate thalamus and contains extensive, reciprocal connections with visual cortex. Although the anatomical and functional...
UNLABELLED
The pulvinar is the largest nucleus in the primate thalamus and contains extensive, reciprocal connections with visual cortex. Although the anatomical and functional organization of the pulvinar has been extensively studied in old and new world monkeys, little is known about the organization of the human pulvinar. Using high-resolution functional magnetic resonance imaging at 3 T, we identified two visual field maps within the ventral pulvinar, referred to as vPul1 and vPul2. Both maps contain an inversion of contralateral visual space with the upper visual field represented ventrally and the lower visual field represented dorsally. vPul1 and vPul2 border each other at the vertical meridian and share a representation of foveal space with iso-eccentricity lines extending across areal borders. Additional, coarse representations of contralateral visual space were identified within ventral medial and dorsal lateral portions of the pulvinar. Connectivity analyses on functional and diffusion imaging data revealed a strong distinction in thalamocortical connectivity between the dorsal and ventral pulvinar. The two maps in the ventral pulvinar were most strongly connected with early and extrastriate visual areas. Given the shared eccentricity representation and similarity in cortical connectivity, we propose that these two maps form a distinct visual field map cluster and perform related functions. The dorsal pulvinar was most strongly connected with parietal and frontal areas. The functional and anatomical organization observed within the human pulvinar was similar to the organization of the pulvinar in other primate species.
SIGNIFICANCE STATEMENT
The anatomical organization and basic response properties of the visual pulvinar have been extensively studied in nonhuman primates. Yet, relatively little is known about the functional and anatomical organization of the human pulvinar. Using neuroimaging, we found multiple representations of visual space within the ventral human pulvinar and extensive topographically organized connectivity with visual cortex. This organization is similar to other nonhuman primates and provides additional support that the general organization of the pulvinar is consistent across the primate phylogenetic tree. These results suggest that the human pulvinar, like other primates, is well positioned to regulate corticocortical communication.
Topics: Adult; Animals; Brain Mapping; Diffusion Magnetic Resonance Imaging; Female; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Memory; Oxygen; Photic Stimulation; Phylogeny; Psychophysics; Pulvinar; Rest; Saccades; Visual Cortex; Visual Fields; Visual Pathways; Young Adult
PubMed: 26156987
DOI: 10.1523/JNEUROSCI.1575-14.2015 -
Cureus Jul 2022Hypospadias is among the most prevalent urogenital malformations in male newborns. It is characterized by the displacement of the urethral meatus to the ventral side of... (Review)
Review
Hypospadias is among the most prevalent urogenital malformations in male newborns. It is characterized by the displacement of the urethral meatus to the ventral side of the penis, an aberrant ventral curve of the penis referred to as "chordee," and an abnormally arranged foreskin with a "hood" found dorsally and lacking foreskin ventrally. Patients may have an extra genitourinary abnormality based on the area of the lesion. In around 70% of cases, the urethral meatus is positioned distally to the shaft, representing a milder form of the disease. The remaining 30% of cases are located proximally, are more complicated, and require further evaluation. Although the origin of hypospadias is mostly obscure, several suggestions exist about genetic susceptibility and hormonal factors. The objective of hypospadias restoration is to restore aesthetic and functional regularity, and surgery is currently advised at a young age, mostly between six and 18 months. At any age, hypospadias can be repaired with an equivalent risk of complications, functional outcomes, and aesthetic outcomes. However, the best age of treatment is still undetermined. Even though the long-term effects on appearance and sexual function are usually good, males may be less likely to make the first move after rectification. Also, people who have hypospadias treated are twice as likely to have problems with their lower urinary tract. These problems can last for years after the initial repair.
PubMed: 36060359
DOI: 10.7759/cureus.27544 -
International Journal of Environmental... Feb 2023The choroid, a multifunctional tissue, has been the focus of research interest for many scientists. Its morphology and morphometry facilitate an understanding of...
The choroid, a multifunctional tissue, has been the focus of research interest for many scientists. Its morphology and morphometry facilitate an understanding of pathological processes within both the choroid and retina. This study aimed to determine the choroidal layer thicknesses in healthy, mixed-breed mesocephalic dogs, both male (M) and female (F), using spectral domain optical coherence tomography (SD-OCT) with radial, cross-sectional, and linear scans. The dogs were divided into two groups based on age: middle-aged (MA) and senior (SN). Thicknesses of choroidal layers, namely RPE-Bruch's membrane-choriocapillaris complex (RPE-BmCc) with tapetum lucidum in the tapetal fundus, the medium-sized vessel layer (MSVL), and the large vessel layer with lamina suprachoroidea (LVLS), as well as whole choroidal thickness (WCT), were measured manually using the caliper function integrated into the OCT software. Measurement was performed dorsally and ventrally at a distance of 5000-6000 μm temporally and nasally at a distance of 4000-7000 μm to the optic disc on enhanced depth scans. The measurements were conducted temporally and nasally in both the tapetal (temporal tapetal: TempT, nasal tapetal: NasT) and nontapetal (temporal nontapetal: TempNT, nasal nontapetal: NasNT) fundus. The ratio of the MSVL thickness to the LVLS thickness for each region was calculated. In all examined dogs, the RPE-BmCc in the dorsal (D) region and MSVL in the Tt region were significantly thicker than those in the other regions. The MSVL was thinner in the ventral (V) region than in the D, TempT, TempNT and NasT regions. The MSVL was significantly thinner in the NasNT region than in the D region. LVLS thickness and WCT were significantly greater in the D and TempT regions than those in the other regions and significantly lesser in the V region than those in the other regions. The MSVL-to-LVLS thickness ratio did not differ between the age groups. Our results reveal that the choroidal thickness profile does not depend on age. Our findings can be used to document the emergence and development of various choroidal diseases in dogs in the future.
Topics: Male; Dogs; Animals; Female; Tomography, Optical Coherence; Cross-Sectional Studies; Choroid; Retina; Fundus Oculi
PubMed: 36833819
DOI: 10.3390/ijerph20043121 -
Cell Reports Apr 2022Locomotion is mediated by spinal circuits that generate movements with a precise coordination and vigor. The assembly of these circuits is defined early during...
Locomotion is mediated by spinal circuits that generate movements with a precise coordination and vigor. The assembly of these circuits is defined early during development; however, whether their organization and function remain invariant throughout development is unclear. Here, we show that the first established fast circuit between two dorsally located V2a interneuron types and the four primary motoneurons undergoes major transformation in adult zebrafish compared with what was reported in larvae. There is a loss of existing connections and establishment of new connections combined with alterations in the mode, plasticity, and strength of synaptic transmission. In addition, we show that this circuit no longer serves as a swim rhythm generator, but instead its components become embedded within the spinal escape circuit and control propulsion following the initial escape turn. Our results thus reveal significant changes in the organization and function of a motor circuit as animals develop toward adulthood.
Topics: Animals; Interneurons; Locomotion; Motor Neurons; Spinal Cord; Zebrafish
PubMed: 35417694
DOI: 10.1016/j.celrep.2022.110654 -
Journal of Wrist Surgery Feb 2018Patients with scapholunate instability usually have pain in the dorsal wrist. This pain may occur due to the impingement between the scaphoid and the dorsal rim of...
Patients with scapholunate instability usually have pain in the dorsal wrist. This pain may occur due to the impingement between the scaphoid and the dorsal rim of the radius when the scaphoid is detached from the lunate. This pain appears as the scaphoid is displaced over the dorsal rim of the radius. The arthroscopic scaphoid 3D (dorsal, dynamic, displacement) test is described here to check this pathologic dorsal displacement of the scaphoid. The test should be performed both in the radiocarpal and midcarpal joints. Traction is released and the arthroscope is set under the lunate when tested in the radiocarpal joint and on the lunate when tested in the midcarpal joint. The scaphoid is manually pushed dorsally at the scaphoid tubercle. If there was no scapholunate instability, all the proximal row bones are minimally displaced: a negative test. If there was scapholunate instability, the scaphoid is displaced dorsally while the lunate remains static: evaluated as positive. This test can add information to the arthroscopic classifications of the scapholunate instability, which explore both the proximal to distal displacement of the scaphoid (the step-off) and the ulnar to radial displacement (the gap), as this test explores the volar to dorsal displacement.
PubMed: 29383283
DOI: 10.1055/s-0037-1601578 -
Journal of Evolutionary Biology Nov 2022Many organisms use conspicuous colour patterns to advertise their toxicity or unpalatability, a strategy known as aposematism. Despite the recognized benefits of this...
Many organisms use conspicuous colour patterns to advertise their toxicity or unpalatability, a strategy known as aposematism. Despite the recognized benefits of this anti-predator tactic, not all chemically defended species exhibit warning coloration. Here, we use a comparative approach to investigate which factors predict the evolution of conspicuousness in frogs, a group in which conspicuous coloration and toxicity have evolved multiple times. We extracted colour information from dorsal and ventral photos of 594 frog species for which chemical defence information was available. Our results show that chemically defended and diurnal species have higher internal chromatic contrast, both ventrally and dorsally, than chemically undefended and/or nocturnal species. Among species that are chemically defended, conspicuous coloration is more likely to occur if species are diurnal. Our results also suggest that the evolution of conspicuous colour is more likely to occur in chemically defended prey with smaller body size. We discuss potential explanations for this association and suggest that prey profitability (related to body size) could be an important force driving the macroevolution of warning signals.
Topics: Animals; Biological Evolution; Anura; Biological Mimicry
PubMed: 36129907
DOI: 10.1111/jeb.14092