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Developmental Biology Dec 1995To challenge the developmental potential of dorsal neural tube cells and test whether single neuroepithelial cells can give rise to the full range of neural tube...
To challenge the developmental potential of dorsal neural tube cells and test whether single neuroepithelial cells can give rise to the full range of neural tube derivatives, we grated a notochord lateral to the closing neural folds. This results in juxtaposition of dorsal and ventral cell types, by inducing floor plate cells and motor neurons dorsally. Clonal analysis with the vital dye lysinated rhodamine dextran showed that both "dorsal" and "ventral" neural tube derivatives can arise from a single precursor. Cells as diverse as sensory ganglion cells, presumptive pigment cells, roof plate cells, motor neurons, and floor plate cells were observed in the same clone. The presence of such diversity within single clones indicates that the responses to dorsal and ventral signals are not mutually exclusive; even in the early neural tube, neuroepithelial cells are not restricted to form only dorsal or ventral neural tube derivatives.
Topics: Animals; Biomarkers; Cell Differentiation; Nervous System; Notochord; Quail; Stem Cells
PubMed: 8612974
DOI: 10.1006/dbio.1995.8038 -
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 -
Journal of Children's Orthopaedics Jun 2020Forearm and distal radius fractures are among the most common fractures in children. Many fractures are definitively treated with closed reduction and casting, however,... (Review)
Review
PURPOSE
Forearm and distal radius fractures are among the most common fractures in children. Many fractures are definitively treated with closed reduction and casting, however, the risk for re-displacement is high (7% to 39%). Proper cast application and the three-point moulding technique are modifiable factors that improve the ability of a cast to maintain the fracture reduction. Many providers univalve the cast to accommodate swelling. This study describes how the location of the univalve cut impacts the pressure at three-point mould sites for a typical dorsally displaced distal radius fracture.
METHODS
We placed nine force-sensing resistors on an arm model to collect pressure data at the three-point mould sites. Sensory inputs were sampled at 15 Hz. Cast padding and a three-point moulded short arm fibreglass cast was applied. The cast was then univalved on the dorsal, volar, radial or ulnar aspect. Pressure recordings were obtained throughout the procedure.
RESULTS
A total of 24 casts were analyzed. Casts univalved in the sagittal plane (dorsal or volar surface) retained up to 16% more pressure across the three moulding sites compared with casts univalved in the coronal plane (radial or ulnar border).
CONCLUSION
Maintaining pressure at the three-point mould prevents loss of reduction at the fracture site. This study shows that univalving the cast dorsally or volarly results in less pressure loss at moulding sites. This should improve the chances of maintaining fracture reductions when compared with radial or ulnar cuts in the cast. Sagittal plane univalving of forearm casts is recommended.
PubMed: 32582392
DOI: 10.1302/1863-2548.14.200034 -
PloS One 2016Several genera belonging to the nematode family Diplogastridae show characteristic dimorphism in their feeding structures; specifically, they have microbial feeding...
Several genera belonging to the nematode family Diplogastridae show characteristic dimorphism in their feeding structures; specifically, they have microbial feeding stenostomatous and predatory eurystomatous morphs. A diplogastrid satellite model species, Pristionchus pacificus, and its close relatives have become a model system for studying this phenotypic plasticity, with intensive physiological and structural studies having been undertaken. However, the many other species that are morphologically and phylogenetically divergent from P. pacificus have not been examined to date. In the present study, the detailed stomatal structure and induction of dimorphism in Neodiplogaster acaloleptae were examined. N. acaloleptae has a fungal feeding stenostomatous morph and a predatory eurystomatous morph. The predatory morph was induced by starvation, high population density, and co-culturing with its potential prey, Caenorhabditis elegans. The feeding behavior of the stenostomatous and eurystomatous morphs of N. acaloleptae was confirmed, demonstrating that 1) the stomatal and pharyngeal movements of the two morphs were basically identical, and 2) the stomatal elements were protracted to cut open the hyphae and/or prey to feed when a N. acaloleptae flips its dorsal movable tooth dorsally and tilts its subventral stegostomatal cylinder ventrally, forming a pair of scissors to cut the food source. The stoma morphology of N. acaloleptae with a single movable tooth and a long stoma is markedly different from that of Pristionchus, which has two movable teeth and a short stoma. It is, however, similar to that of Mononchoides, tentatively a sister to Neodiplogaster.
Topics: Animals; Caenorhabditis elegans; Coculture Techniques; Feeding Behavior; Female; Male; Nematoda; Pharynx; Phenotype; Phylogeny; Polymerase Chain Reaction; Population Density; Predatory Behavior
PubMed: 27196730
DOI: 10.1371/journal.pone.0155715 -
Neurosurgical Focus: Video Oct 2021The course of the facial nerve (FN) has been extensively investigated in patients with vestibular schwannomas (VSs). FN running dorsally to the tumor capsule accounts...
The course of the facial nerve (FN) has been extensively investigated in patients with vestibular schwannomas (VSs). FN running dorsally to the tumor capsule accounts for less than 3% of the cases. Diffusion tensor imaging (DTI)-based fiber tracking helps to preoperatively identify the FN. During surgery, a higher risk of injury is associated with the dorsal location of the FN. The authors demonstrate the nuances and tricks to identify and preserve a dorsal displaced FN during resection of a large VS, T3b according to the Hannover classification, through the retrosigmoid-transmeatal approach. The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID2182.
PubMed: 36285236
DOI: 10.3171/2021.7.FOCVID2182 -
Frontiers in Neural Circuits 2015Commissural neurons project across the midline at all levels of the central nervous system (CNS), providing bilateral communication critical for the coordination of...
Commissural neurons project across the midline at all levels of the central nervous system (CNS), providing bilateral communication critical for the coordination of motor activity and sensory perception. Midline crossing at the spinal ventral midline has been extensively studied and has revealed that multiple developmental lineages contribute to this commissural neuron population. Ventral midline crossing occurs in a manner dependent on Robo3 regulation of Robo/Slit signaling and the ventral commissure is absent in the spinal cord and hindbrain of Robo3 mutants. Midline crossing in the spinal cord is not limited to the ventral midline, however. While prior anatomical studies provide evidence that commissural axons also cross the midline dorsally, little is known of the genetic and molecular properties of dorsally-crossing neurons or of the mechanisms that regulate dorsal midline crossing. In this study, we describe a commissural neuron population that crosses the spinal dorsal midline during the last quarter of embryogenesis in discrete fiber bundles present throughout the rostrocaudal extent of the spinal cord. Using immunohistochemistry, neurotracing, and mouse genetics, we show that this commissural neuron population includes spinal inhibitory neurons and sensory nociceptors. While the floor plate and roof plate are dispensable for dorsal midline crossing, we show that this population depends on Robo/Slit signaling yet crosses the dorsal midline in a Robo3-independent manner. The dorsally-crossing commissural neuron population we describe suggests a substrate circuitry for pain processing in the dorsal spinal cord.
Topics: Age Factors; Amino Acids; Animals; Axons; Body Patterning; Embryo, Mammalian; Gene Expression Regulation, Developmental; Green Fluorescent Proteins; Membrane Proteins; Mice; Mice, Transgenic; Motor Activity; Mutation; Nerve Tissue Proteins; Neural Cell Adhesion Molecule L1; Neural Inhibition; Nociceptors; Receptors, Cell Surface; Signal Transduction; Spinal Cord; Transcription Factors
PubMed: 26257608
DOI: 10.3389/fncir.2015.00036 -
Cureus Oct 2022Osteochondromas are bone lesions composed of medullary and cartilaginous bone covered by a cap of hyaline cartilage. The presence of medullary and cortical bone with the...
Osteochondromas are bone lesions composed of medullary and cartilaginous bone covered by a cap of hyaline cartilage. The presence of medullary and cortical bone with the continuity of the tumor is pathognomonic for osteochondroma and aid in establishing the diagnosis. We report a case of a two-year-old girl who presented to our clinic following her mother noticing a palpable, growing, and painful mass on her left scapula. There was no limitation in the range of motion. A clear-cut mass was seen on the dorsal aspect and palpated measuring around 2.5x3 cm. Surgical excision of the mass followed by histologic examination confirmed osteochondroma. Upon follow-up, the patient had no pain and had a full range of left shoulder motion without discomfort or pain. In conclusion, scapular exostoses are very rare and more so when they present dorsally. Symptomatic lesions can be managed effectively with surgical excision of exostosis.
PubMed: 36311482
DOI: 10.7759/cureus.30558 -
Urology Jun 2014To describe our 14-year experience with a 1-stage tissue transfer urethroplasty technique.
OBJECTIVE
To describe our 14-year experience with a 1-stage tissue transfer urethroplasty technique.
METHODS
Eighteen patients underwent reconstruction with circumferential buccal grafting. All patients had anterior urethral strictures that included segments of total or near-total obliteration not amenable to excisional or augmented anastomotic repair and intact corpus spongiosum that could serve as a graft recipient bed. The mobilized corpus spongiosum was incised dorsally without transection, thereby preserving the continuity of the blood supply within the spongy tissue. Buccal mucosa was quilted to the corporal bodies to reconstruct the dorsal aspect of the urethra. Where there was obliterative or near-obliterative stricture disease, additional buccal mucosa was quilted to the dorsally incised, nontransected corpus spongiosum in continuity with the distally and proximally spatulated urethra. The repair was then completed by approximating dorsal and ventral buccal mucosal graft segments.
RESULTS
Follow-up included voiding cystourethrogram at 3 weeks, cystoscopy 4 months after surgery (1 patient refused), and subsequent follow-up. There was 1 early stricture recurrence, which was successfully treated with direct vision internal urethrotomy (success 94%, and 100% after 1 urethrotomy). Every patient was contacted and assessed at the time of manuscript preparation. All patients are currently free of obstructive symptoms attributed to stricture disease with a mean follow-up of 50 months (range, 5-171 months).
CONCLUSION
Dorsal and ventral buccal grafting appears to be an excellent option for a 1-stage repair of long obliterative anterior urethral strictures and strictures that include segments of obliterative or near-obliterative disease in selected cases.
Topics: Adult; Aged; Cohort Studies; Follow-Up Studies; Graft Survival; Humans; Male; Middle Aged; Mouth Mucosa; Plastic Surgery Procedures; Retrospective Studies; Risk Assessment; Severity of Illness Index; Treatment Outcome; Urethral Stricture; Urologic Surgical Procedures, Male; Young Adult
PubMed: 24745799
DOI: 10.1016/j.urology.2014.01.024 -
The Journal of Hand Surgery Feb 2011To determine the amount of scaphoid and lunate translation that occurs in normal cadaver wrists during wrist motion, and to quantify the change in ulnar translation when... (Comparative Study)
Comparative Study
PURPOSE
To determine the amount of scaphoid and lunate translation that occurs in normal cadaver wrists during wrist motion, and to quantify the change in ulnar translation when specific dorsal and volar wrist ligaments were sectioned.
METHODS
We measured the scaphoid and lunate motion of 37 cadaver wrists during wrist radioulnar deviation and flexion-extension motions using a wrist joint motion simulator. We quantified the location of the centroids of the bones during each motion in the intact wrists and after sectioning either 2 dorsal ligaments along with the scapholunate interosseous ligament or 2 volar ligaments and the scapholunate interosseous ligament.
RESULTS
In the intact wrist, the scaphoid and lunate statistically translated radially with wrist ulnar deviation. With wrist flexion, the scaphoid moved volarly and the lunate dorsally. After sectioning either the dorsal or volar ligaments, the scaphoid moved radially. After sectioning the dorsal or volar ligaments, the lunate statistically moved ulnarly and volarly.
CONCLUSIONS
Measurable changes in the scaphoid and lunate translation occur with wrist motion and change with ligament sectioning. However, for the ligaments that were sectioned, these changes are small and an attempt to clinically measure these translations of the scaphoid and lunate radiographically may be limited. The results support the conclusion that ulnar translocation does not occur unless multiple ligaments are sectioned. Injury of more than the scapholunate interosseous ligament along with either the dorsal intercarpal and dorsal radiocarpal or the radioscaphocapitate and scaphotrapezial ligaments is needed to have large amounts of volar and ulnar translation.
Topics: Adult; Aged; Aged, 80 and over; Analysis of Variance; Biomechanical Phenomena; Cadaver; Female; Humans; Ligaments, Articular; Lunate Bone; Male; Middle Aged; Movement; Range of Motion, Articular; Reference Values; Scaphoid Bone; Wrist Joint
PubMed: 21276893
DOI: 10.1016/j.jhsa.2010.11.023 -
Cortex; a Journal Devoted To the Study... Jan 2022100 years ago, Liepmann highlighted the role of left ventro-dorsal lesions for impairments in conceptual (rather ventral) and motor (more dorsal) related aspects of...
100 years ago, Liepmann highlighted the role of left ventro-dorsal lesions for impairments in conceptual (rather ventral) and motor (more dorsal) related aspects of apraxia. Many studies thereafter attributed to an extended left fronto-temporo-parietal network. Yet, to date there are only few studies that looked at apraxic performance in the selection and application of familiar versus novel tools. In the current study we applied modern voxel-based lesion-symptom mapping (VLSM) to analyze neural correlates of impaired selection and application of familiar versus novel tools. 58 left (LBD) and 51 right brain damaged (RBD) stroke patients participated in the Novel Tools Test (NTT) and the Familiar Tools Test (FTT) of the Diagnostic Instrument for Limb Apraxia (DILA-S). We further assessed performance in control tasks, namely semantic knowledge (BOSU), visuo-spatial working memory (Corsi Block Tapping) and meaningless imitation of gestures (IML). Impaired tool use was most pronounced after LBD. Our VLSM results in the LBD group suggested that selection- versus application-related aspects of praxis and semantics of familiar versus novel tool use can be behaviorally and neuro-anatomically differentiated. For impairments in familiar tool tasks, the major focus of lesion maps was rather ventral while deficiencies in novel tool tasks went along with rather dorsal lesions. Affected selection processes were linked to rather anterior lesions, while impacted application processes went along with rather posterior lesion maps. In our study, particular tool selection processes were rather specific for familiar versus novel tools. Foci for lesion overlaps of experimental and control tasks were noticed ventrally for semantic knowledge and FTT, in fronto-parietal regions for working memory and NTT, and ventro-dorsally for imitation of meaningless gestures and the application of NTT and FTT. We visualized our current interpretation within a neuroanatomical model for apraxia of tool use.
Topics: Apraxias; Functional Laterality; Gestures; Humans; Imitative Behavior; Magnetic Resonance Imaging; Stroke
PubMed: 34801831
DOI: 10.1016/j.cortex.2021.10.002