JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
NRP1-mediated Sema3A signals coordinate laminar formation in the developing chick optic tectum.
Development
PUBLISHED: 09-04-2014
Show Abstract
Hide Abstract
The optic tectum comprises multiple layers, which are formed by radial and tangential migration during development. Here, we report that Neuropilin 1 (NRP1)-mediated Sema3A signals are involved in the process of tectal laminar formation, which is elaborated by tangential migration. In the developing chick tectum, NRP1, a receptor for Sema3A, is expressed in microtubule-associated protein 2 (MAP2)-positive intermediate layers IV and V. Sema3A itself is a diffusible guidance factor and is expressed in the overlying layer VI. Using stable fluorescent labeling of tectal cells, we show that MAP2-positive intermediate layers are formed by the neurons that have been dispersed by tangential migration along the tectal efferent axons. When Sema3A was mis-expressed during laminar formation, local Sema3A repelled the tangential migrants, thus eliminating MAP2-positive neurons that expressed NRP1. Furthermore, in the absence of the MAP2-positive neurons, tectal layers were disorganized into an undulated form, indicating that MAP2-positive intermediate layers are required for proper laminar formation. These results suggest that NRP1-mediated Sema3A signals provide repulsive signals for MAP2-positive neurons to segregate tectal layers, which is important in order to coordinate laminar organization of the optic tectum.
Related JoVE Video
Follistatin-like 5 is expressed in restricted areas of the adult mouse brain: Implications for its function in the olfactory system.
Congenit Anom (Kyoto)
PUBLISHED: 03-05-2014
Show Abstract
Hide Abstract
Follistatin-like 5 (Fstl5), a member of the follistatin family of genes, encodes a secretory glycoprotein. Previous studies revealed that other members of this family including Fstl1 and Fstl3 play an essential role in development, homeostasis, and congenital disorders. However, the in vivo function of Fstl5 is poorly understood. To gain insight into the function of Fstl5 in the mouse central nervous system, we examined the Fstl5 expression pattern in the adult mouse brain. The results of in situ hybridization analysis showed a highly restricted pattern of Fstl5, namely, with localization in the olfactory system, hippocampal CA3 area and granular cell layer of the cerebellum. Restricted expression in the olfactory system suggests a possible role for Fstl5 in maintaining odor perception.
Related JoVE Video
[Results of a questionnaire on efforts to increase research-oriented doctors].
Kaibogaku Zasshi
PUBLISHED: 04-23-2013
Show Abstract
Hide Abstract
We surveyed medical and dental schools to promote the exchange of information about university efforts to increase the number of research-oriented doctors. Periods in which students rotate through laboratories to conduct research were reported by more than two thirds of universities. Many comments asserted that these efforts are effective. However, a small number of respondents reported low student motivation and insufficient time for laboratory experience. MD-PhD courses, in which students take a leave of absence in the middle of undergraduate training and follow a PhD curriculum, have been employed by more than 10 universities. However, relatively few students have chosen such programs. Modified MD-PhD courses have recently been introduced by several universities. In these courses, by taking part of the graduate school curriculum in advance, undergraduate students can shorten the time they spend in graduate school. Students who take such courses are increasing. There were many opinions that extra positions and financial support for research-oriented doctors are effective and should be enhanced. There were also many opinions that emphasize the importance of identifying research-oriented students, improving laboratory working environments, attending academic meetings and inter-university consortia to maintain students motivation, and promoting collaboration with departments of clinical medicine.
Related JoVE Video
Development of the dorsal ramus of the spinal nerve in the mouse embryo: involvement of semaphorin 3A in dorsal muscle innervation.
Congenit Anom (Kyoto)
PUBLISHED: 03-10-2013
Show Abstract
Hide Abstract
The spinal nerve, which is composed of dorsal root ganglion (DRG) sensory axons and spinal motor axons, forms the dorsal ramus projecting to the dorsal musculature. By using the free-floating immunohistochemistry method, we closely examined the spatiotemporal pattern of the formation of the dorsal ramus and the relationship between its projection to the myotome/dorsal musculature and semaphorin 3A (Sema3A), which is an axonal guidance molecule. In embryonic day (E) 10.5-E11.5 wild-type mouse embryos, we clearly showed the existence of a waiting period for the dorsal ramus projection to the myotome. In contrast, in E10.5-E11.5 Sema3A-deficient embryos, the dorsal ramus fibers projected beyond the edge of the myotome without exhibiting the waiting period for projection. These results strongly suggest that the delayed innervation by dorsal ramus fibers may be caused by Sema3A-induced axon repulsion derived from the myotome. Next, by performing culture experiments, we confirmed that E12.5 mouse axons responded to Sema3A-induced repulsion. Together, our results imply that Sema3A may play a key role in the proper development of the dorsal ramus projection.
Related JoVE Video
Elucidation of target muscle and detailed development of dorsal motor neurons in chick embryo spinal cord.
J. Comp. Neurol.
PUBLISHED: 02-15-2013
Show Abstract
Hide Abstract
The avian cervical spinal cord includes motoneurons (MNs) that send their axons through the dorsal roots. They have been called dorsal motoneurons (dMNs) and assumed to correspond to MNs of the accessory nerve that innervate the cucullaris muscle (SAN-MNs). However, their target muscles have not been elucidated to date. The present study sought to determine the targets and the specific combination of transcription factors expressed by dMNs and SAN-MNs and to describe the detailed development of dMNs. Experiments with tracing techniques confirmed that axons of dMNs innervated the cucullaris muscle. Retrogradely labeled dMNs were distributed in the ventral horn of C3 and more caudal segments. In most cases, some dMNs were also observed in the C2 segment. It was also demonstrated that SAN-MNs existed in the ventral horn of the C1-2 segments and the adjacent caudal hindbrain. Both SAN-MNs and dMNs expressed Isl1 but did not express Isl2, MNR2, or Lhx3. Rather, these MNs expressed Phox2b, a marker for branchial motoneurons (brMNs), although the intensity of expression was weaker. Dorsal MNs and SAN-MNs were derived from the Nkx2.2-positive precursor domain and migrated dorsally. Dorsal MNs remain in the ventral domain of the neural tube, unlike brMNs in the brainstem. These results indicate that dMNs and SAN-MNs belong to a common MN population innervating the cucullaris muscle and also suggest that they are similar to brMNs of the brainstem, although there are differences in Phox2b expression and in the final location of each population. J. Comp. Neurol. 521: 2987-3002, 2013. © 2013 Wiley Periodicals, Inc.
Related JoVE Video
Highly efficient retrograde gene transfer into motor neurons by a lentiviral vector pseudotyped with fusion glycoprotein.
PLoS ONE
PUBLISHED: 01-01-2013
Show Abstract
Hide Abstract
The development of gene therapy techniques to introduce transgenes that promote neuronal survival and protection provides effective therapeutic approaches for neurological and neurodegenerative diseases. Intramuscular injection of adenoviral and adeno-associated viral vectors, as well as lentiviral vectors pseudotyped with rabies virus glycoprotein (RV-G), permits gene delivery into motor neurons in animal models for motor neuron diseases. Recently, we developed a vector with highly efficient retrograde gene transfer (HiRet) by pseudotyping a human immunodeficiency virus type 1 (HIV-1)-based vector with fusion glycoprotein B type (FuG-B) or a variant of FuG-B (FuG-B2), in which the cytoplasmic domain of RV-G was replaced by the corresponding part of vesicular stomatitis virus glycoprotein (VSV-G). We have also developed another vector showing neuron-specific retrograde gene transfer (NeuRet) with fusion glycoprotein C type, in which the short C-terminal segment of the extracellular domain and transmembrane/cytoplasmic domains of RV-G was substituted with the corresponding regions of VSV-G. These two vectors afford the high efficiency of retrograde gene transfer into different neuronal populations in the brain. Here we investigated the efficiency of the HiRet (with FuG-B2) and NeuRet vectors for retrograde gene transfer into motor neurons in the spinal cord and hindbrain in mice after intramuscular injection and compared it with the efficiency of the RV-G pseudotype of the HIV-1-based vector. The main highlight of our results is that the HiRet vector shows the most efficient retrograde gene transfer into both spinal cord and hindbrain motor neurons, offering its promising use as a gene therapeutic approach for the treatment of motor neuron diseases.
Related JoVE Video
[Final report of the working group for the future planning of the Japanese Association of Anatomists].
Kaibogaku Zasshi
PUBLISHED: 08-17-2011
Show Abstract
Hide Abstract
The working group for the future planning of the Japanese Association of Anatomists (JAA) has been working to address the issues that were consulted from the president of JAA since October 2009. After making the interim report in March 2010, a public hearing for general members of the JAA was held and a final report was submitted to the President in January 2011. The report contains the analysis of the current situation, the directions in which we should proceed, and recommendations of concrete actions that JAA should take for each issue. The issues discussed were as follows: 1. Future prospects of anatomy and morphological sciences. How can we maintain the specialties of morphological and anatomical sciences in the rapidly advancing field of life sciences and develop collaborations with other fields? 2. Improvement of the JAA academic meetings. How can we increase JAA members and young participants in the academic meetings of the JAA? 3. Fostering the next generation of young researchers. How can we increase young researchers graduated from the schools of Medicine or Dentistry? 4. Future prospects of education of gross anatomy. Prospects of education in gross anatomy and the body donation registration system in relation with some new cadaver-related movements.
Related JoVE Video
[Draft of guidelines for human body dissection for clinical anatomy education and research and commentary].
Kaibogaku Zasshi
PUBLISHED: 08-17-2011
Show Abstract
Hide Abstract
This article analyses the Draft of Guidelines for Human Body Dissection for Clinical Anatomy Education and Research drawn by the Study Group for Future Training Systems of Surgical Skills and Procedures established by the Fiscal Year 2010 research program of the Ministry of Health, Labor and Welfare. The purpose of the Draft of Guidelines is: First, to lay out the required basic guidelines for human cadaver usage to allow medical and dental faculty to conduct clinical education and research in accordance with existing regulations. Second, the guidelines are expected to give physicians a regulatory framework to carry out cadaver training in accordance with the current legal framework. This article explains the Draft of Guidelines in detail, outlines the future of cadaver training, and describes issues which must still be solved.
Related JoVE Video
[Draft of Guidelines for Human Body Dissection for Clinical Anatomy Education and Research and commentary].
Nihon Geka Gakkai Zasshi
PUBLISHED: 08-09-2011
Show Abstract
Hide Abstract
This article analyses the Draft of Guidelines for Human Body Dissection for Clinical Anatomy Education and Research drawn by the Study Group for Future Training Systems of Surgical Skills and Procedures established by the Fiscal Year 2010 research program of the Ministry of Health, Labor and Welfare. The purpose of the Draft of Guidelines is: First, to lay out the required basic guidelines for human cadaver usage to allow medical and dental faculty to conduct clinical education and research in accordance with existing regulations. Second, the guidelines are expected to give physicians a regulatory framework to carry out cadaver training in accordance with the current legal framework. This article explains the Draft of Guidelines in detail, outlines the future of cadaver training, and describes issues which must still be solved.
Related JoVE Video
A lentiviral strategy for highly efficient retrograde gene transfer by pseudotyping with fusion envelope glycoprotein.
Hum. Gene Ther.
PUBLISHED: 01-27-2011
Show Abstract
Hide Abstract
The lentiviral vector system based on human immunodeficiency virus type 1 (HIV-1) is used extensively in gene therapy trials of neurological and neurodegenerative diseases. Retrograde axonal transport of viral vectors offers a great advantage to the delivery of genes into neuronal cell bodies that are situated in regions distant from the injection site. Pseudotyping of HIV-1-based vectors with selective variants of rabies virus glycoprotein (RV-G) increases gene transfer via retrograde transport into the central nervous system. Because large-scale application for gene therapy trials requires high titer stocks of the vector, pseudotyping of a lentiviral vector that produces more efficient retrograde transport is needed. In the present study, we developed a novel vector system for highly efficient retrograde gene transfer by pseudotyping an HIV-1 vector with a fusion envelope glycoprotein (termed FuG-B) in which the cytoplasmic domain of RV-G was substituted by the corresponding part of vesicular stomatitis virus glycoprotein. The FuG-B pseudotype shifted the transducing property of the lentiviral vector and enhanced the retrograde transport-mediated gene transfer into different brain regions innervating the striatum with greater efficiency than that of the RV-G pseudotype in mice. In addition, injection of the FuG-B-pseudotyped vector into monkey striatum (caudate and putamen) allowed for highly efficient gene delivery into the nigrostriatal dopamine system, which is a major target for gene therapy of Parkinsons disease. Our strategy provides a powerful tool for the treatment of certain neurological and neurodegenerative diseases by promoting retrograde gene delivery via a lentiviral vector.
Related JoVE Video
Rho/Rho-kinase signaling pathway controls axon patterning of a specified subset of cranial motor neurons.
Eur. J. Neurosci.
PUBLISHED: 01-11-2011
Show Abstract
Hide Abstract
Cranial motor neurons, which are divided into somatic motor (SM), branchiomotor (BM) and visceral motor (VM) neurons, form distinct axonal trajectories to innervate their synapse targets. Rho GTPase regulates various neuronal functions through one of the major effector proteins, Rho-kinase. Here, we addressed the in vivo role of the Rho/Rho-kinase signaling pathway in axon patterning of cranial motor neurons. We performed conditional expression of a dominant-negative mutant for RhoA or Rho-kinase in transgenic mice by using the Cre-loxP system to suppress the activity of these molecules in developing cranial motor neurons. Blockade of the Rho/Rho-kinase signaling pathway caused defects in the patterning of SM axons but not in that of BM/VM axons, in which defects were accompanied by reduced muscle innervation and reduced synapse formation by SM neurons. In addition, blockade of the signaling pathway shifted the trajectory of growing SM axons in explant cultures, whereas it did not appear to affect the rate of spontaneous axonal outgrowth. These results indicate that the Rho/Rho-kinase signaling pathway plays an essential role in the axon patterning of cranial SM neurons during development.
Related JoVE Video
Role for netrin-1 in sensory axonal guidance in higher vertebrates.
Fukushima J Med Sci
PUBLISHED: 12-17-2009
Show Abstract
Hide Abstract
During development, dorsal root ganglion (DRG) neurons in higher vertebrates extend their axons centrally to the spinal cord through the dorsal root entry zone (DREZ) and peripherally to muscle and skin targets. After entering the spinal cord, DRG axons project into the dorsal mantle layer. In this review, we focus on evidence showing the role for netrin-1 in forming sensory axonal trajectories. Netrin-1 is a diffusible axonal guidance molecule that chemorepels developing DRG axons. When DRG axons project toward the DREZ, ventral spinal cord-derived netrin-1 prevents DRG axons from projecting aberrantly toward the ventral spinal cord. At later stages, the dorsal spinal cord cells transiently express netrin-1. This dorsal spinal cord-derived netrin-1 prevents DRG axons from invading the dorsal spinal cord during the waiting period. Together, the data reviewed provide strong evidence that netrin-1 plays a crucial role in sensory axon projection during development.
Related JoVE Video
Netrin-1 signaling for sensory axons: Involvement in sensory axonal development and regeneration.
Cell Adh Migr
PUBLISHED: 04-14-2009
Show Abstract
Hide Abstract
During development, dorsal root ganglion (DRG) neurons extend their axons toward the dorsolateral part of the spinal cord and enter the spinal cord through the dorsal root entry zone (DREZ). After entering the spinal cord, these axons project into the dorsal mantle layer after a waiting period of a few days. We revealed that the diffusible axonal guidance molecule netrin-1 is a chemorepellent for developing DRG axons. When DRG axons orient themselves toward the DREZ, netrin-1 proteins derived from the ventral spinal cord prevent DRG axons from projecting aberrantly toward the ventral spinal cord and help them to project correctly toward the DREZ. In addition to the ventrally derived netrin-1, the dorsal spinal cord cells adjacent to the DREZ transiently express netrin-1 proteins during the waiting period. This dorsally derived netrin-1 contributes to the correct guidance of DRG axons to prevent them from invading the dorsal spinal cord. In general, there is a complete lack of sensory axonal regeneration after a spinal cord injury, because the dorsal column lesion exerts inhibitory activities toward regenerating axons. Netrin-1 is a novel candidate for a major inhibitor of sensory axonal regeneration in the spinal cord; because its expression level stays unchanged in the lesion site following injury, and adult DRG neurons respond to netrin-1-induced axon repulsion. Although further studies are required to show the involvement of netrin-1 in preventing the regeneration of sensory axons in CNS injury, the manipulation of netrin-1-induced repulsion in the CNS lesion site may be a potent approach for the treatment of human spinal injuries.
Related JoVE Video
Laminin peptide YIGSR and its receptor regulate sensory axonal response to the chemoattractive guidance cue in the chick embryo.
J. Neurosci. Res.
PUBLISHED: 03-26-2009
Show Abstract
Hide Abstract
During early development, centrally projecting dorsal root ganglion (DRG) neurons extend their axons toward the dorsal spinal cord. We previously reported the involvement of dorsal spinal cord-derived chemoattraction in this projection (Masuda et al. [ 2007] Neuroreport 18:1645-1649). However, the molecular nature of this attraction is not clear. Here we show that laminin-1 (alpha1beta1gamma1) is expressed strongly along the pathway of DRG axons and that its 67-kDa receptor (67LR) is present on DRG cells. This evidence suggests that laminin-1-67LR signaling may be involved in DRG axonal guidance. By employing culture assays, we show that laminin-1 or the YIGSR peptide, a soluble peptide of the laminin beta1 chain, promotes the DRG axonal response to dorsal spinal cord-derived chemoattraction. By using a function-blocking antibody against 67LR, we show that the anti-67LR antibody blocks the modulation of DRG axonal response by the YIGSR peptide in vitro. Furthermore, the in ovo injection of the anti-67LR antibody inhibits the DRG axonal growth toward the dorsal spinal cord. These results provide evidence that the YIGSR peptide promotes dorsal spinal cord-derived chemoattraction via 67LR to contribute to the formation of the initial trajectories of developing DRG axons.
Related JoVE Video
Expression pattern of LRR and Ig domain-containing protein (LRRIG protein) in the early mouse embryo.
Gene Expr. Patterns
PUBLISHED: 03-20-2009
Show Abstract
Hide Abstract
The combination of leucine-rich repeat (LRR) and immunoglobulin-like (Ig) domains is found in the domain architecture of the Trk neurotrophin receptor protein. Recently dozens of such proteins simultaneously carrying LRR and Ig domains as the Trk receptors have been identified. Given the significant biological roles of Trk and such newly identified proteins, we have searched the public database for human proteins with LRR and Ig domains (collectively termed the leucine-rich repeat and Ig domain-containing protein, LRRIG protein, in this study), and have analyzed the mRNA expression pattern of mouse orthologs of obtained human LRRIG proteins at embryonic day 10. The list of the LRRIG proteins includes 36 human proteins: four LINGO, three NGL, five SALM, three NLRR, three Pal, two ISLR, three LRIG, two GPR, two Adlican, two Peroxidasin-like proteins, three Trk neurotrophin receptors, a yet unnamed protein AAI11068, and three AMIGO. Some molecules (LINGO2, LINGO4, NGL1, SALM1, SALM5, and TrkB) were expressed exclusively in neuronal tissues, whereas others (ISLR1, GPR124, and Adlican2) exhibited non-neuronal expression profiles. However, the majority of LRRIG protein family exhibited broad mRNA tissue-expression profiles.
Related JoVE Video
Laser capture microdissection and cDNA array analysis for identification of mouse KIAA/FLJ genes differentially expressed in the embryonic dorsal spinal cord.
Brain Res.
PUBLISHED: 01-31-2009
Show Abstract
Hide Abstract
During early development, centrally projecting dorsal root ganglion (DRG) neurons extend their axons toward the dorsal spinal cord. We previously reported that this projection is achieved by dorsal spinal cord-derived chemoattraction. However, the molecular nature of the chemotrophic cue is not yet fully understood. To identify novel genes differentially expressed in the dorsal spinal cord in the embryonic day 10.5 mouse, we used the Kazusa cDNA array system comprising approximately 1700 mouse KIAA/FLJ (mKIAA/mFLJ) cDNA clones and laser capture microdissection (LCM) in combination with PCR-based cDNA amplification. We observed that a certain population of genes showed significantly increased expression in the dorsal spinal cord. In situ hybridization analysis verified the expression of mRNAs of 6 genes (Hip1r, Nav2, Fstl5, Cacna1h, Bcr, and Bmper) in the cells that constitute the dorsal spinal cord. The dorsal spinal cord-specific genes identified in this study provide a basis for studying the molecular nature of the neural development including the axonal guidance of DRG neurons. These results also demonstrate that the combined use of LCM coupled with the Kazusa cDNA array technology will be useful for the identification of large proteins expressed in the restricted small regions of embryos.
Related JoVE Video
Development of the dorsal ramus of the spinal nerve in the chick embryo: a close relationship between development and expression of guidance cues.
Brain Res.
Show Abstract
Hide Abstract
The spinal nerve, which is composed of dorsal root ganglion (DRG) axons and spinal motor axons, divides into ventral and dorsal rami. Although the development of the ventral ramus has been examined in considerable detail, that of the dorsal ramus has not. Therefore, we first examined the spatial-temporal pattern of the dorsal ramus formation in the chick embryo, with special reference to the projection to the dermamyotome and its derivatives. Next, we focused on two guidance molecules, chick semaphorin 3A (SEMA3A) and fibroblast growth factor 8 (FGF8), because these are the best candidates as molecules for controlling the dorsal ramus formation. Using in situ hybridization and immunohistochemistry methods, we clearly showed a close relationship between the spatial-temporal expression of SEMA3A/FGF8 and the projection of dorsal ramus fibers to the dorsal muscles. We further examined the axonal response of motor and DRG neurons to SEMA3A and FGF8. We showed that motor axons responded to both SEMA3A-induced repulsion and FGF8-induced attraction. On the other hand, DRG axons responded to SEMA3A-induced repulsion but not to FGF8-induced attraction. These findings suggest that FGF8-induced attraction may guide early motor axons beneath the myotome and that SEMA3A-induced repulsion may prevent these early motor axons from entering the myotome. Our results also imply that the loss of SEMA3A expression in the dorsal muscles may lead to the gross projection of the dorsal ramus fibers into the dorsal muscles. Together, SEMA3A and FGF8 may contribute to the proper formation of the dorsal ramus.
Related JoVE Video
Neurogenin2 expression together with NeuroM regulates GDNF family neurotrophic factor receptor ?1 (GFR?1) expression in the embryonic spinal cord.
Dev. Biol.
Show Abstract
Hide Abstract
In many regions of the nervous system, the combinatorial action of transcriptional factors specifies the individual fate of neuronal subtypes. Contrary to this, we report that a single transcriptional factor controls a phenotype shared by different subtypes of neurons, namely the expression of a neurotrophic factor receptor in the spinal cord. Along the dorsoventral axis of the chick embryo spinal cord, the expression pattern of a specific receptor for glial cell line derived-neurotrophic factor (GDNF family of receptors ?1: GFR?1) was related to that of two basic helix-loop-helix (bHLH) transcriptional factors (NeuroM and Neurogenin2: Ngn2). In ovo electroporation in the chick embryo revealed that the overexpression of NeuroM alone was sufficient to induce ectopic GFR?1 expression without overt neuronal differentiation, whereas the suppression of NeuroM activity resulted in the specific loss of GFR?1 expression, indicating that NeuroM may act as a differentiation factor for GFR?1 expression. Ngn2 overexpression was also sufficient to induce precocious GFR?1 expression. However, the forced expression of both obligate suppressor and activator forms of Ngn2 also induced aberrant GFR?1 expression. Thus, any deviation from an optimum level of Ngn2 expression resulted in aberrant GFR?1 expression. Consistent with this, manipulation of Ngn2 expression levels by other bHLH factors also resulted in ectopic GFR?1 expression. For example, the downregulation by Ascl1 and the upregulation by Ptf1a induced ectopic GFR?1 expression, irrespective of endogenous expression patterns of Ascl1 and Ptf1a (Ascl1/Ptf1) in the spinal cord. The suppression of Ascl1/Ptf1a activities abolished Ngn2 and GFR?1 expression, even in Ascl1/Ptf1a-negative regions. These data indicate the presence of a distinct regulatory sequence for a determinant of GFR?1 expression, in which Ascl1/Ptf1a may competitively intervene to stochastically modulate default Ngn2 expression levels. Thus, Ngn2 together with NeuroM serves as readout to regulate GFR?1 expression, which occurs in multiple subtypes of spinal neurons.
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.