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1.
Methods Mol Biol ; 2562: 1-23, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36272065

RESUMO

For 70 years from the very beginning of developmental biology, the salamander embryo was the pre-eminent model for these studies. Here I review the major discoveries that were made using salamander embryos including regionalization of the mesoderm; patterning of the neural plate; limb development, with the pinnacle being Spemann's Nobel Prize for the discovery of the organizer; and the phenomenon of induction. Salamanders have also been the major organism for elucidating discoveries in organ regeneration, and these are described here too beginning with Spallanzani's experiments in 1768. These include the neurotrophic hypothesis of regeneration, studies of aneurogenic limbs, the concept of dedifferentiation and transdifferentiation, and advances in understanding pattern formation via molecules located on the cell surface. Also described is the prodigious power of brain and spinal cord regeneration and discoveries from lens regeneration, all of which reveal how important salamanders have been as research models.


Assuntos
Mesoderma , Urodelos , Animais , Extremidades
2.
Methods Mol Biol ; 2562: 109-122, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36272070

RESUMO

In situ hybridization is a standard procedure for visualizing mRNA transcripts in tissues. The recent adoption of fluorescent probes and new signal amplification methods have facilitated multiplexed RNA imaging in tissue sections and whole tissues. Here we present protocols for multiplexed hybridization chain reaction fluorescence in situ hybridization (HCR-FISH) staining, imaging, cell segmentation, and mRNA quantification in regenerating axolotl tissue sections. We also present a protocol for whole-mount staining and imaging of developing axolotl limbs.


Assuntos
Ambystoma mexicanum , Corantes Fluorescentes , Animais , Ambystoma mexicanum/genética , Hibridização in Situ Fluorescente/métodos , RNA Mensageiro/genética , Extremidades , RNA
3.
Methods Mol Biol ; 2562: 209-216, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36272078

RESUMO

Genetic methods in axolotls (Ambystoma mexicanum) remain in their infancy which has hampered the study of limb regeneration. There is much room for advancement, especially with respect to spatiotemporal regulation of gene expression. Secreted growth factors play a major role in each stage of regeneration. The use of slow-release beads is one of the most effective methods to control the spatiotemporal expression of secretory gene products. The topical administration of secreted factors by slow-release beads may also prove effective for future applications in non-regenerative animals and for medical applications in humans, in which genetic methods are not available. In this chapter, we describe a methodology for using and implanting slow-release beads to deliver exogenous growth factors to salamanders.


Assuntos
Ambystoma mexicanum , Extremidades , Animais , Humanos , Extremidades/fisiologia , Ambystoma mexicanum/genética , Peptídeos e Proteínas de Sinalização Intercelular
4.
Methods Mol Biol ; 2562: 217-233, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36272079

RESUMO

When the Accessory Limb Model (ALM) regenerative assay was first published by Endo, Bryant, and Gardiner in 2004, it provided a robust system for testing the cellular and molecular contributions during each of the basic steps of regeneration: the formation of the wound epithelium, neural induction of the apical epithelial cap, and the formation of a positional disparity between blastema cells. The basic ALM procedure was developed in the axolotl and involves deviating a limb nerve into a lateral wound and grafting skin from the opposing side of the limb axis into the site of injury. In this chapter, we will review the studies that lead to the conception of the ALM, as well as the studies that have followed the development of this assay. We will additionally describe in detail the standard ALM surgery and how to perform this surgery on different limb positions.


Assuntos
Ambystoma mexicanum , Tecido Nervoso , Animais , Ambystoma mexicanum/fisiologia , Extremidades/fisiologia , Pele/inervação , Epitélio
5.
Methods Mol Biol ; 2562: 235-247, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36272080

RESUMO

Embryo grafts have been an experimental pillar in developmental biology, and particularly, in amphibian biology. Grafts have been essential in constructing fate maps of different cell populations and migratory patterns. Likewise, autografts and allografts in older larvae or adult salamanders have been widely used to disentangle mechanisms of regeneration. The combination of transgenesis and grafting has widened even more the application of this technique.In this chapter, we provide a detailed protocol for embryo transplants in the axolotl (Ambystoma mexicanum ). The location and stages to label connective tissue, muscle, or blood vessels in the limb and blood cells in the whole animal. However, the potential of embryo transplants is enormous and impossible to cover in one chapter. Furthermore, we provide a protocol for blastema transplantation as an example of allograft in older larvae.


Assuntos
Ambystoma mexicanum , Extremidades , Animais , Ambystoma mexicanum/fisiologia , Extremidades/fisiologia , Tecido Conjuntivo , Larva/fisiologia
6.
Methods Mol Biol ; 2562: 249-258, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36272081

RESUMO

Retinoic acid (RA) and the family of molecules based on vitamin A known as retinoids have remarkable effects on limb regeneration in salamanders and newts and cause whole limb duplications in a concentration-dependent manner. They respecify all three axes of the limb-the proximodistal, the anteroposterior, and the dorsoventral axis. As a result, complete limbs can be induced to regenerate from distal amputation planes producing two limbs in tandem. Here, we describe the basic methods for undertaking these experiments as well as the use of new synthetic retinoids which have retinoic acid receptor-selective actions. These will be valuable tools in future studies on the molecular basis of limb duplications and thus our understanding of the nature of positional information in the regenerating salamander limb.


Assuntos
Tretinoína , Vitamina A , Animais , Tretinoína/farmacologia , Retinoides/farmacologia , Salamandridae , Extremidades , Receptores do Ácido Retinoico
7.
Skeletal Radiol ; 52(1): 1-8, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35835878

RESUMO

This review illustrates the multimodality assessment of transfascial muscle and other soft tissue herniations of the extremities. Transfascial herniations of the extremities can develop from congenital or acquired disruptions of the deep fascia, resulting in herniation of the underlying muscle, nerve, or soft tissue tumor into the subcutaneous tissues. While most patients present with a painless subcutaneous nodule that may change in size with muscle activation, some may experience focal or diffuse extremity symptoms such as pain and paresthesias. Although the diagnosis may be clinically suspected, radiologic evaluation is useful for definitive diagnosis and characterization. Ultrasound is the preferred modality for initial workup through a focused and dynamic examination. Magnetic resonance imaging can be utilized for equivocal, complicated, and preoperative cases. Computed tomography is less useful in the evaluation of transfascial herniations in the extremities due to similarities in the attenuation between muscle and fascia, which can decrease the conspicuity of small defects.


Assuntos
Extremidades , Hérnia , Humanos , Extremidades/diagnóstico por imagem , Fáscia/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Músculos
8.
Methods Mol Biol ; 2583: 159-173, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36418733

RESUMO

Behavioral phenotyping approaches for neonatal mice are important for investigating early alterations in brain development and function, relevant to neurodevelopmental disorders in humans. This chapter describes a behavioral screen that can provide an overall profile of function across the neonatal and preweaning period while also minimizing pup stress and disturbance of the maternal environment. Testing begins when mice are between 6 and 8 days in age, with additional evaluations at discrete time points until postnatal day (PD) 20-21, using tests for negative geotaxis, surface righting reflex, activity in an open field, acoustic startle responses and sensorimotor gating, and limb clasp.


Assuntos
Transtornos do Neurodesenvolvimento , Reflexo de Sobressalto , Humanos , Recém-Nascido , Camundongos , Animais , Transtornos do Neurodesenvolvimento/diagnóstico , Modelos Animais de Doenças , Triagem Neonatal , Extremidades
9.
Artigo em Alemão | MEDLINE | ID: mdl-36323271

RESUMO

OBJECTIVE: Limb fractures account for a large proportion of all orthopedic diseases in pet rabbits and are a common reason for presentation. The fracture etiologies and characteristics vary considerably in comparison to trauma of the extremities in cats and dogs. For this reason, conservative and surgical treatment options need to be adapted. To our knowledge, long-term effects of limb fracture therapies in pet rabbits have not been described scientifically. MATERIALS AND METHODS: This article features a case series of 13 pet rabbits with limb fractures. Their medical records were analyzed retrospectively and all patients were presented for a follow-up examination including clinical and orthopedic examination. RESULTS: Orthopedic anomalies (abducted limb postures) were identified in four patients. Arthrotic ossification was found in twelve of thirteen animals - in six cases to a high extent. Measurement of the fractured bones revealed a shortening in ten of thirteen cases. CONCLUSION AND CLINICAL RELEVANCE: Orthopedic long-term complications following fracture treatments were commonly detected in the patient population of this study. Permanent issues may result in anomalies of limb posture or postural control which are not noticed by the rabbit owners in every case. Ultimately, the patients should be examined routinely after the conclusion of fracture therapy in order to detect and adequately treat possible orthopedic complications.


Assuntos
Extremidades , Fraturas Ósseas , Animais , Coelhos , Extremidades/lesões , Fraturas Ósseas/terapia , Fraturas Ósseas/veterinária , Estudos Retrospectivos , Animais de Estimação , Resultado do Tratamento
10.
Surg Infect (Larchmt) ; 23(9): 817-828, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36350736

RESUMO

Background: Open fractures, defined as fractures communicating with the environment through a skin wound, cause substantial morbidity after traumatic injury. Current evidence supports administration of prophylactic systemic antibiotic agents to patients with open extremity fractures to decrease infectious complications. Methods: The Therapeutic and Guidelines Committee of The Surgical Infection Society convened to revise guidelines for antibiotic use in open fractures. PubMed was queried for pertinent studies. Evaluation of the published evidence was performed using the GRADE framework. All committee members voted to accept or reject each recommendation. Results: In type I or II open extremity fractures, we recommend against administration of extended-spectrum antibiotic coverage compared with gram-positive coverage alone to decrease infections complications, hospital length of stay or mortality. In type III open extremity fractures, we recommend antibiotic therapy for no more than 24 hrs after injury, in the absence of clinical signs of active infection, to decrease infectious complications, hospital length of stay or mortality, and we recommend against extended antimicrobial coverage beyond gram-positive organisms to decrease infectious complications, hospital length of stay or mortality. In type III open extremity fractures with associated bone loss, we recommend antibiotic therapy in addition to systemic therapy to decrease infectious complications. Conclusions: Although antibiotic agents remain a standard of care for infection prevention after open extremity fractures, our findings and surveys of clinical practice patterns clearly show that additional robust clinical trials are needed to provide stronger corroborating evidence.


Assuntos
Anti-Infecciosos , Fraturas Expostas , Humanos , Fraturas Expostas/complicações , Fraturas Expostas/tratamento farmacológico , Fraturas Expostas/cirurgia , Antibacterianos/uso terapêutico , Antibioticoprofilaxia , Anti-Infecciosos/uso terapêutico , Extremidades , Infecção da Ferida Cirúrgica/tratamento farmacológico , Infecção da Ferida Cirúrgica/prevenção & controle , Infecção da Ferida Cirúrgica/complicações , Estudos Retrospectivos
11.
Medicine (Baltimore) ; 101(44): e31631, 2022 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-36343072

RESUMO

RATIONALE: Clear cell sarcoma of soft tissue (CCSST) is a rare malignant tumor that occurs in the extremities of young adults. CCSST has been documented to have atypical histopathological features, such as epidermotropism or myxoid differentiation, which may set pitfalls in the differential diagnosis. We report a case of CCSST with plasmacytoid morphology which has never been described. PATIENT CONCERNS: A 15-year-old male, presented with a 5-cm mass in his left inguinal area. DIAGNOSIS: Positron emission tomography-computed tomography examination showed nodules in the left groin and the lung, the latter was considered metastasis. A core needle biopsy with the diagnosis of CCSST with plasmacytoid morphology was made according to histology, immunostaining, and molecular analysis. INTERVENTIONS: The patient received chemotherapy of doxorubicin and ifosfamide. OUTCOMES: The patient failed to respond to the standard chemotherapy and deceased twelve months after diagnosis. LESSONS: This special case of CCSST with plasmacytoid features demonstrated a morphological variation never been documented and may easily lead to misdiagnosis. For such cases, molecular analysis is essential to provide solid evidence for accurate diagnosis.


Assuntos
Sarcoma de Células Claras , Neoplasias de Tecidos Moles , Masculino , Adulto Jovem , Humanos , Adolescente , Sarcoma de Células Claras/diagnóstico , Sarcoma de Células Claras/tratamento farmacológico , Sarcoma de Células Claras/patologia , Neoplasias de Tecidos Moles/diagnóstico , Neoplasias de Tecidos Moles/tratamento farmacológico , Neoplasias de Tecidos Moles/patologia , Ifosfamida/uso terapêutico , Doxorrubicina/uso terapêutico , Extremidades/patologia
12.
Bioinspir Biomim ; 18(1)2022 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-36332271

RESUMO

Many legged robots have taken insight from animals to run, jump, and climb. Very few, however, have extended the flexibility of limbs to the task of swimming. In this paper, we address the study of multi-modal limbed locomotion by extending our lateral plane reduced order dynamic model of climbing to swimming. Following this, we develop a robot, AquaClimber, which utilizes the model's locomotive style, similar to human freestyle swimming, to propel itself through fluid and to climb vertical walls, as well as transition between the two. A comparison of simulation and model results indicate that the simulation can predict how hand design, arm compliance, and driving frequency affect swimming speed and behavior. Using this reduced order model, we have successfully developed the first limbed aquatic-scansorial multi-modal robot.


Assuntos
Robótica , Natação , Animais , Biomimética/métodos , Desenho de Equipamento , Extremidades , Locomoção
13.
BMC Cancer ; 22(1): 1122, 2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36320002

RESUMO

BACKGROUND: Surgical treatment for recurrent bone tumors in the extremities still presents a challenge. This study was designed to evaluate the clinical value of microwave ablation in the treatment of recurrent bone tumors. METHODS: We present 15 patients who underwent microwave ablation for recurrent bone tumors during the last 7 years. The following parameters were analyzed for outcome evaluation: general condition, surgical complications, local disease control, overall survival, and functional score measured using the Musculoskeletal Tumor Society (MSTS) 93 scoring system. RESULTS: Percutaneous microwave ablation in one patient with osteoid osteoma and another with bone metastasis resulted in postoperative pain relief. Thirteen patients received intraoperative microwave ablation before curettage or resection, including those with giant cell tumors of bone (6), chondroblastoma (2), osteosarcoma (2), undifferentiated sarcoma (1), and bone metastases (2). All patients achieved reasonable local tumor control in the mean follow-up of 29.9 months. The functional score was 24.1 for the 15 patients 6 months after the operation. Four patients had tumor metastasis and died, whereas 3 patients with tumors survived, and the remaining 8 patients without the disease survived. CONCLUSIONS: Microwave ablation represents an optional method for local control in treating recurrent bone tumors in the extremities.


Assuntos
Neoplasias Ósseas , Micro-Ondas , Humanos , Micro-Ondas/uso terapêutico , Estudos Retrospectivos , Resultado do Tratamento , Neoplasias Ósseas/patologia , Extremidades/patologia
14.
BMC Vet Res ; 18(1): 390, 2022 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-36335398

RESUMO

BACKGROUND: The Importance of the appendicular skeleton in the conformation, shape and physiology of wild animals especially carnivores for adaptation and survival cannot be overemphasized, as limited and obsolete information on the bones of the forelimb necessitated this study. Matured adult African lions (Male and female) that weighed 173 kg and 112 kg were obtained at different times after post mortem examinations of their carcasses. Bone preparation was achieved via cold water maceration after proper skin and muscle removal to a barest minimum. RESULTS: The acromion process of the scapula consisted of a ventral hamate and caudal suprahamate processes. The Clavicle was absent in this species. The musculospiral groove of the humerus was more or less absent while its supracondyloid foramen and crest were positioned above the medial condyle and lateral condyle respectively. The radio-ulna presented a twisted appearance with the radius slightly curved thereby creating an extensive interosseous space that spanned its entire length. The seven (7) carpal bones were uniquely arranged in two rows while the 5 metacarpals anchored 5 digits with 3 phalanges except the first with 2 phalanges each. Two sesamoid bones were located on the ventral surface of each Metacarpophalangeal joint. None was seen on its dorsal surface. The 3rd phalanx had a unique appearance with a crescent plate projecting from the ventral cavity. The average total number of bones constituting the pectoral limb was 80. CONCLUSION: Numerical information and detailed anatomical features of the pectoral limb bones of the African lion (Panthera leo leo) have added some valuable literature to science. This further serves as a baseline data for future scientific exposition on this species.


Assuntos
Leões , Animais , Feminino , Masculino , Leões/anatomia & histologia , Animais Selvagens , Extremidades , Membro Anterior , Ulna
15.
Hum Mov Sci ; 86: 103019, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36327550

RESUMO

Interlimb temporal synchrony and spatial symmetry of centre of pressure (COP) displacements may be vital contributors to standing balance control. In previous work among stroke survivors, low-frequency COP displacements (< 0.4 Hz) were proposed to arise from centre of mass (COM) dynamics, or from proactive exploratory processes. COP displacements among higher frequencies (>0.4 Hz), in contrast, have been attributed to corrective balance responses to internal perturbations. The present study extends this work to explore age-related alterations in such stability control processes during standing balance. The combined COP displacements from both limbs (COPnet) in addition to individual-limb COP timeseries were calculated from synchronous force platform data obtained from 19 younger adults and 19 older adults during a 60 s trial of quiet standing. The discrete wavelet transform was used to decompose the anteroposterior and mediolateral COPnet, in addition to the individual-limb timeseries, into low-frequency and high-frequency bandwidths. Root-mean-squared (RMS) amplitudes of high- and low-frequency COPnet displacements were calculated. The cross-correlation coefficient was used to assess the extent of between-limb temporal synchronization, while the ratio of individual-limb RMS amplitudes was used to assess between-limb spatial symmetry within each high- and low-frequency bandwidth. We observed greater high-frequency anteroposterior COPnet displacements among older adults, without age related differences in the lower frequency bandwidth or in the mediolateral direction. Further, older adults exhibited greater high-frequency anteroposterior between-limb synchronization, without age-related differences in the low frequency bandwidth, or among any of the spatial symmetry variables. The present age-related alterations in COPnet could represent a conservative strategy to ensure stability, whereby age-related challenges in stability maintenance during standing are offset by greater demands on stability control. Further, increased high frequency between-limb temporal synchronization among older adults may suggest a loss of adaptability in balance corrective responses during standing.


Assuntos
Postura , Acidente Vascular Cerebral , Humanos , Idoso , Postura/fisiologia , Equilíbrio Postural/fisiologia , Extremidades , Envelhecimento
16.
Nat Commun ; 13(1): 7144, 2022 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-36414634

RESUMO

Misinformation can come directly from public figures and organizations (referred to here as "elites"). Here, we develop a tool for measuring Twitter users' exposure to misinformation from elites based on the public figures and organizations they choose to follow. Using a database of professional fact-checks by PolitiFact, we calculate falsity scores for 816 elites based on the veracity of their statements. We then assign users an elite misinformation-exposure score based on the falsity scores of the elites they follow on Twitter. Users' misinformation-exposure scores are negatively correlated with the quality of news they share themselves, and positively correlated with estimated conservative ideology. Additionally, we analyze the co-follower, co-share, and co-retweet networks of 5000 Twitter users and find an ideological asymmetry: estimated ideological extremity is associated with more misinformation exposure for users estimated to be conservative but not for users estimated to be liberal. Finally, we create an open-source R library and an Application Programming Interface (API) making our elite misinformation-exposure estimation tool openly available to the community.


Assuntos
Mídias Sociais , Humanos , Bases de Dados Factuais , Extremidades , Biblioteca Gênica , Comunicação
17.
Proc Biol Sci ; 289(1984): 20221322, 2022 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-36196542

RESUMO

Hind limbs undergo dramatic changes in loading conditions during the transition from quadrupedal to bipedal locomotion. For example, the most early diverging bipedal jerboas (Rodentia: Dipodidae) are some of the smallest mammals in the world, with body masses that range between 2-4 g. The larger jerboa species exhibit developmental and evolutionary fusion of the central three metatarsals into a single cannon bone. We hypothesize that small body size and metatarsal fusion are mechanisms to maintain the safety factor of the hind limb bones despite the higher ground reaction forces associated with bipedal locomotion. Using finite-element analysis to model collisions between the substrate and the metatarsals, we found that body size reduction was insufficient to reduce bone stress on unfused metatarsals, based on the scaled dynamics of larger jerboas, and that fused bones developed lower stresses than unfused bones when all metatarsals are scaled to the same size and loading conditions. Based on these results, we conclude that fusion reinforces larger jerboa metatarsals against high ground reaction forces. Because smaller jerboas with unfused metatarsals develop higher peak stresses in response to loading conditions scaled from larger jerboas, we hypothesize that smaller jerboas use alternative dynamics of bipedal locomotion to reduce the impact of collisions between the foot and substrate.


Assuntos
Ossos do Metatarso , Animais , Extremidades , , Locomoção , Roedores
18.
Am Nat ; 200(5): E207-E220, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36260855

RESUMO

AbstractThe G matrix, which quantifies the genetic architecture of traits, is often viewed as an evolutionary constraint. However, G can evolve in response to selection and may also be viewed as a product of adaptive evolution. Convergent evolution of G in similar environments would suggest that G evolves adaptively, but it is difficult to disentangle such effects from phylogeny. Here, we use the adaptive radiation of Anolis lizards to ask whether convergence of G accompanies the repeated evolution of habitat specialists, or ecomorphs, across the Greater Antilles. We measured G in seven species representing three ecomorphs (trunk-crown, trunk-ground, and grass-bush). We found that the overall structure of G does not converge. Instead, the structure of G is well conserved and displays a phylogenetic signal consistent with Brownian motion. However, several elements of G showed signatures of convergence, indicating that some aspects of genetic architecture have been shaped by selection. Most notably, genetic correlations between limb traits and body traits were weaker in long-legged trunk-ground species, suggesting effects of recurrent selection on limb length. Our results demonstrate that common selection pressures may have subtle but consistent effects on the evolution of G, even as its overall structure remains conserved.


Assuntos
Lagartos , Animais , Filogenia , Ecossistema , Fenótipo , Extremidades
20.
Elife ; 112022 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-36286408

RESUMO

Deciphering how the brain regulates motor circuits to control complex behaviors is an important, long-standing challenge in neuroscience. In the fly, Drosophila melanogaster, this is coordinated by a population of ~ 1100 descending neurons (DNs). Activating only a few DNs is known to be sufficient to drive complex behaviors like walking and grooming. However, what additional role the larger population of DNs plays during natural behaviors remains largely unknown. For example, they may modulate core behavioral commands or comprise parallel pathways that are engaged depending on sensory context. We evaluated these possibilities by recording populations of nearly 100 DNs in individual tethered flies while they generated limb-dependent behaviors, including walking and grooming. We found that the largest fraction of recorded DNs encode walking while fewer are active during head grooming and resting. A large fraction of walk-encoding DNs encode turning and far fewer weakly encode speed. Although odor context does not determine which behavior-encoding DNs are recruited, a few DNs encode odors rather than behaviors. Lastly, we illustrate how one can identify individual neurons from DN population recordings by using their spatial, functional, and morphological properties. These results set the stage for a comprehensive, population-level understanding of how the brain's descending signals regulate complex motor actions.


Assuntos
Drosophila melanogaster , Odorantes , Animais , Drosophila melanogaster/fisiologia , Neurônios/fisiologia , Extremidades , Dinâmica Populacional
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