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Frontiers in Neuroanatomy 2022Despite recent improvements in diffusion-weighted imaging, spinal cord tractography is not used in routine clinical practice because of difficulties in reconstructing...
Despite recent improvements in diffusion-weighted imaging, spinal cord tractography is not used in routine clinical practice because of difficulties in reconstructing tractograms, with a pertinent tri-dimensional-rendering, in a long post-processing time. We propose a new full tractography approach to the cervical spinal cord without extensive manual filtering or multiple regions of interest seeding that could help neurosurgeons manage various spinal cord disorders. Four healthy volunteers and two patients with either cervical intramedullary tumors or spinal cord injuries were included. Diffusion-weighted images of the cervical spinal cord were acquired using a Philips 3 Tesla machine, 32 diffusion directions, 1,000 s/mm -value, 2 × 2 × 2 mm voxel size, reduced field-of-view (ZOOM), with two opposing phase-encoding directions. Distortion corrections were then achieved using the FSL software package, and tracking of the full cervical spinal cord was performed using the DSI Studio software (quantitative anisotropy-based deterministic algorithm). A unique region of avoidance was used to exclude everything that is not of the nervous system. Fiber tracking parameters used adaptative fractional anisotropy from 0.015 to 0.045, fiber length from 10 to 1,000 mm, and angular threshold of 90°. In all participants, a full cervical cord tractography was performed from the medulla to the C7 spine level. On a ventral view, the junction between the medulla and spinal cord was identified with its pyramidal bulging, and by an invagination corresponding to the median ventral sulcus. On a dorsal view, the fourth ventricle-superior, middle, and inferior cerebellar peduncles-was seen, as well as its floor and the obex; and gracile and cuneate tracts were recognized on each side of the dorsal median sulcus. In the case of the intramedullary tumor or spinal cord injury, the spinal tracts were seen to be displaced, and this helped to adjust the neurosurgical strategy. This new full tractography approach simplifies the tractography pipeline and provides a reliable 3D-rendering of the spinal cord that could help to adjust the neurosurgical strategy.
PubMed: 36237419
DOI: 10.3389/fnana.2022.993464 -
Prion 2015Prion proteins (PrP(C)) are cell membrane glycoproteins that can be found in many cell types, but specially in neurons. Many studies have suggested PrP(C)'s...
Prion proteins (PrP(C)) are cell membrane glycoproteins that can be found in many cell types, but specially in neurons. Many studies have suggested PrP(C)'s participation in metal transport and cellular protection against stress in the central nervous system (CNS). On the other hand PrP(Sc), the misfolded isoform of PrP(C) and the pathogenic agent in transmissible spongiform encephalopathies (TSE), has been associated with brain metal dyshomeostasis in prion diseases. Thus, changes in metal concentration associated with protein misfolding and aggregation have been reported for human and animal prion diseases, as well as for other neurodegenerative disorders, such as Parkinson's and Alzheimer's disease. The use of metal concentrations in tissues as surrogate markers for early detection of TSEs has been suggested. Studies on the accumulation of metals in free-ranging white-tailed deer have not been conducted. This study established concentrations of copper, iron, manganese, and magnesium in 2 diagnostic tissues used for CWD testing (obex and retropharyngeal lymph nodes (RLN)). We compared these concentrations between tissues and in relation to CWD status. We established reference intervals (RIs) for these metals and explored their ability to discriminate between CWD-positive and CWD-negative animals. Our results indicate that independent of CWD status, white-tailed deer accumulate higher concentrations of Fe, Mn and Mg in RLN than in obex. White-tailed deer infected with CWD accumulated significantly lower concentrations of Mn and Fe than CWD-negative deer. These patterns differed from other species infected with prion diseases. Overlapping values between CWD positive and negative groups indicate that evaluation of these metals in obex and RLN may not be appropriate as a diagnostic tool for CWD infection in white-tailed deer. Because the CWD-negative deer were included in constructing the RIs, high specificities were expected and should be interpreted with caution. Due to the low sensitivity derived from the RIs, we do not recommend using metal concentrations for disease discrimination.
Topics: Animals; Deer; Illinois; Lymph Nodes; Metals; Models, Biological; Sensitivity and Specificity; Wasting Disease, Chronic
PubMed: 25695915
DOI: 10.1080/19336896.2015.1019194 -
Brain Pathology (Zurich, Switzerland) Jan 2021Sudden unexpected death in epilepsy (SUDEP) is mechanistically complex and one probable cause is seizure-related respiratory dysfunction. Medullary respiratory...
Sudden unexpected death in epilepsy (SUDEP) is mechanistically complex and one probable cause is seizure-related respiratory dysfunction. Medullary respiratory regulatory nuclei include the pre-Bötzinger complex (pre-BötC) in the ventrolateral medulla (VLM), the medullary raphé nuclei (MR) and nucleus of solitary tract in the dorsomedial medulla (DMM). The region of the VLM also contains intermingled tyrosine hydroxylase (TH) catecholaminergic neurones which directly project to the pre-BötC and regulate breathing under hypoxic conditions and our aim was to evaluate these neurones in SUDEP cases. In post-mortem cases from three groups [SUDEP (18), epilepsy controls (8) and non-epilepsy controls (16)] serial sections of medulla (obex + 2 to + 13 mm) were immunolabeled for TH. Three regions of interest (ROI) were outlined (VLM, DMM and MR) and TH-immunoreactive (TH-IR) neurones were evaluated using automated detection for overall labeling index (neurones and processes) and neuronal densities and compared between groups and relative to obex level. C-fos immunoreactivity was also semi-quantitatively evaluated in these regions. We found no significant difference in the density of TH-IR neurones or labeling index between the groups in all regions. Significantly more TH-IR neurones were present in the DMM region than VLM in non-epilepsy cases only (P < 0.01). Regional variations in TH-IR neurones with obex level were seen in all groups except SUDEP. We also identified occasional TH neurones in the MR region in all groups. There was significantly less c-fos labeling in the VLM and MR in SUDEP than non-epilepsy controls but no difference with epilepsy controls. In conclusion, in this series we found no evidence for alteration of total medullary TH-IR neuronal numbers in SUDEP but noted some differences in their relative distribution in the medulla and c-fos neurones compared to control groups which may be relevant to the mechanism of death.
Topics: Adolescent; Adult; Child; Child, Preschool; Female; Humans; Infant; Male; Medulla Oblongata; Middle Aged; Neurons; Sudden Unexpected Death in Epilepsy; Tyrosine 3-Monooxygenase; Young Adult
PubMed: 32852867
DOI: 10.1111/bpa.12891 -
Brain : a Journal of Neurology Jun 2018Sudden unexpected death in epilepsy (SUDEP) is a leading cause of premature death in patients with epilepsy. One hypothesis proposes that sudden death is mediated by...
Sudden unexpected death in epilepsy (SUDEP) is a leading cause of premature death in patients with epilepsy. One hypothesis proposes that sudden death is mediated by post-ictal central respiratory depression, which could relate to underlying pathology in key respiratory nuclei and/or their neuromodulators. Our aim was to investigate neuronal populations in the ventrolateral medulla (which includes the putative human pre-Bötzinger complex) and the medullary raphe. Forty brainstems were studied comprising four groups: 14 SUDEP, six epilepsy controls, seven Dravet syndrome cases and 13 non-epilepsy controls. Serial sections through the medulla (from obex 1 to 10 mm) were stained for Nissl, somatostatin, neurokinin 1 receptor (for pre-Bötzinger complex neurons) and galanin, tryptophan hydroxylase and serotonin transporter (neuromodulatory systems). Using stereology total neuronal number and densities, with respect to obex level, were measured. Whole slide scanning image analysis was used to quantify immunolabelling indices as well as co-localization between markers. Significant findings included reduction in somatostatin neurons and neurokinin 1 receptor labelling in the ventrolateral medulla in sudden death in epilepsy compared to controls (P < 0.05). Galanin and tryptophan hydroxylase labelling was also reduced in sudden death cases and more significantly in the ventrolateral medulla region than the raphe (P < 0.005 and P < 0.05). With serotonin transporter, reduction in labelling in cases of sudden death in epilepsy was noted only in the raphe (P ≤ 0.01); however, co-localization with tryptophan hydroxylase was significantly reduced in the ventrolateral medulla. Epilepsy controls and cases with Dravet syndrome showed less significant alterations with differences from non-epilepsy controls noted only for somatostatin in the ventrolateral medulla (P < 0.05). Variations in labelling with respect to obex level were noted of potential relevance to the rostro-caudal organization of respiratory nuclear groups, including tryptophan hydroxylase, where the greatest statistical difference noted between all epilepsy cases and controls was at obex 9-10 mm (P = 0.034), the putative level of the pre-Bötzinger complex. Furthermore, there was evidence for variation with duration of epilepsy for somatostatin and neurokinin 1 receptor. Our findings suggest alteration to neuronal populations in the medulla in SUDEP with evidence for greater reduction in neuromodulatory neuropeptidergic and mono-aminergic systems, including for galanin, and serotonin. Other nuclei need to be investigated to evaluate if this is part of more widespread brainstem pathology. Our findings could be a result of previous seizures and may represent a pathological risk factor for SUDEP through impaired respiratory homeostasis during a seizure.
Topics: Adolescent; Adult; Autopsy; Death, Sudden; Epilepsy; Female; Humans; Magnetic Resonance Imaging; Male; Medulla Oblongata; Membrane Proteins; Middle Aged; Nerve Tissue Proteins; Raphe Nuclei; Retrospective Studies; Severity of Illness Index; Young Adult
PubMed: 29608654
DOI: 10.1093/brain/awy078 -
Frontiers in Veterinary Science 2021Chronic wasting disease (CWD) is a transmissible prion disorder, primarily affecting free-ranging and captive cervids in North America (United States and Canada), South...
Chronic wasting disease (CWD) is a transmissible prion disorder, primarily affecting free-ranging and captive cervids in North America (United States and Canada), South Korea, and Europe (Finland, Norway, and Sweden). Current diagnostic methods used in the United States for detection of CWD in hunter harvested deer involve demonstration of the causal misfolded prion protein (PrP) in the obex or retropharyngeal lymph nodes (RLNs) using an antigen detection ELISA as a screening tool, followed by a confirmation by the gold standard method, immunohistochemistry (IHC). Real-time quaking-induced conversion (RT-QuIC) assay is a newer approach that amplifies misfolded CWD prions and has facilitated CWD prion detection in a variety of tissues, body fluids, and excreta. The current study was undertaken to compare ELISA, IHC, and RT-QuIC on RLNs ( = 1,300 animals) from white-tailed deer (WTD) in Michigan. In addition, prescapular, prefemoral and popliteal lymph nodes collected from a small subset ( = 7) of animals were tested. Lastly, the location of the positive samples within Michigan was documented and the percentage of CWD positive RLNs was calculated by sex and age. ELISA and RT-QuIC detected PrP in 184 and 178 out of 1,300 RLNs, respectively. Of the 184 ELISA positive samples, 176 were also IHC positive for CWD. There were seven discordant results when comparing IHC and ELISA. RT-QuIC revealed that six of the seven samples matched the IHC outcomes. One RLN was negative by IHC, but positive by ELISA and RT-QuIC. RT-QuIC, IHC, and ELISA also detected PrP in prescapular, prefemoral and popliteal lymph nodes. CWD infection heterogeneities were observed in different age and sex groups, with young males having higher CWD prevalence. All, except one, CWD positive RLNs analyzed were from ten Counties geographically located in the West Michigan region of the Lower Peninsula. Taken together, we show evidence that the RT-QuIC assay is comparable to ELISA and IHC and could be helpful for routine CWD detection in surveillance programs. RT-QuIC also demonstrated that CWD prions are distributed across lymph nodes in a variety of anatomic locations. A multi-laboratory validation on blinded sample panels is underway and is likely to help to provide insight into the variability (lab-to-lab), analytical sensitivity, and specificity of gold standard diagnostics vs. RT-QuIC assay.
PubMed: 35118153
DOI: 10.3389/fvets.2021.824815 -
Frontiers in Neuroanatomy 2021The human brainstem harbors neuronal aggregates that ensure the maintenance of several vital functions. It also acts as a major relay structure for the neuronal...
The human brainstem harbors neuronal aggregates that ensure the maintenance of several vital functions. It also acts as a major relay structure for the neuronal information that travels between the cerebral cortex, the cerebellum and the spinal cord. As such, this relatively small portion of the human brain houses a multitude of ascending and descending fibers that course among numerous nuclei whose exact boundaries are still uncertain. Such a large number of nuclei and fiber tracts confined to a relatively small and compact brain region imposes upon the brainstem a highly complex cytoarchitectonic organization that still needs to be deciphered. The present work provides a topographic atlas of the human brainstem composed of 45 anatomical plates, each containing a pair of adjacent sections stained with Cresyl Violet and Luxol Fast Blue to help delineating brainstem nuclei and fiber tracts, respectively. The plates, which cover the entire midbrain, pons and medulla oblongata, are composed of equally-spaced sections referenced and aligned parallel to the ponto-mesencephalic junction rather than the fastigium or the obex. This topographic landmark is particularly suitable for neurosurgical interventions aiming at specific nuclei of the mesencephalic tegmentum. In complement, we provide 8 anatomical plates containing adjacent sections stained for choline acetyltransferase and Luxol Fast Blue, taken through the midbrain and the pons. This open access atlas of the human brainstem is intended to assist neuroanatomists, neurosurgeons and neuropathologists in their work.
PubMed: 34483849
DOI: 10.3389/fnana.2021.627656 -
PloS One 2013Transmissible spongiform encephalopathies (TSEs), or prion diseases, are a uniformly fatal family of neurodegenerative diseases in mammals that includes chronic wasting...
Transmissible spongiform encephalopathies (TSEs), or prion diseases, are a uniformly fatal family of neurodegenerative diseases in mammals that includes chronic wasting disease (CWD) of cervids. The early and ante-mortem identification of TSE-infected individuals using conventional western blotting or immunohistochemistry (IHC) has proven difficult, as the levels of infectious prions in readily obtainable samples, including blood and bodily fluids, are typically beyond the limits of detection. The development of amplification-based seeding assays has been instrumental in the detection of low levels of infectious prions in clinical samples. In the present study, we evaluated the cerebrospinal fluid (CSF) of CWD-exposed (n=44) and naïve (n=4) deer (n=48 total) for CWD prions (PrP(d)) using two amplification assays: serial protein misfolding cyclic amplification with polytetrafluoroethylene beads (sPMCAb) and real-time quaking induced conversion (RT-QuIC) employing a truncated Syrian hamster recombinant protein substrate. Samples were evaluated blindly in parallel with appropriate positive and negative controls. Results from amplification assays were compared to one another and to obex immunohistochemistry, and were correlated to available clinical histories including CWD inoculum source (e.g. saliva, blood), genotype, survival period, and duration of clinical signs. We found that both sPMCAb and RT-QuIC were capable of amplifying CWD prions from cervid CSF, and results correlated well with one another. Prion seeding activity in either assay was observed in approximately 50% of deer with PrP(d) detected by IHC in the obex region of the brain. Important predictors of amplification included duration of clinical signs and time of first tonsil biopsy positive results, and ultimately the levels of PrP(d) identified in the obex by IHC. Based on our findings, we expect that both sPMCAb and RT-QuIC may prove to be useful detection assays for the detection of prions in CSF.
Topics: Animals; Blotting, Western; Deer; Wasting Disease, Chronic
PubMed: 24282599
DOI: 10.1371/journal.pone.0081488 -
Journal of Veterinary Diagnostic... Jul 2019is a small subshrub that is distributed throughout Brazil and is responsible for lysosomal storage disease and occasional reproductive problems in cattle, goats,...
is a small subshrub that is distributed throughout Brazil and is responsible for lysosomal storage disease and occasional reproductive problems in cattle, goats, equids, sheep, and deer. We describe herein the clinical, epidemiologic, and pathologic features of hydrallantois in 3 cows naturally poisoned by in Rio Grande do Sul State, Brazil. Clinically, all cows had marked abdominal distension and mild ataxia. After natural death or euthanasia, autopsies revealed that the abdominal distension in all 3 cases was caused by severe enlargement of the uterus, which contained 100-120 L of translucent fluid within the allantois, in addition to adventitial placentation. Microscopic evaluation of the placenta revealed marked diffuse edema, sometimes with a myxomatous appearance. Neurons in the cerebellum and obex were swollen, with mild-to-moderate cytoplasmic granular vacuolation. Histochemical examination with lectins ConA, WGA, and sWGA revealed mild-to-marked staining in the cytoplasm of neurons of the cerebellum and medulla at the level of the obex, indicating the occurrence of α-mannosidosis.
Topics: Allantois; Animals; Brain Diseases; Brazil; Cattle; Cattle Diseases; Female; Malvaceae; Plant Poisoning
PubMed: 31122163
DOI: 10.1177/1040638719850610 -
G3 (Bethesda, Md.) Jul 2022Despite implementation of enhanced management practices, chronic wasting disease in US white-tailed deer (Odocoileus virginianus) continues to expand geographically....
Despite implementation of enhanced management practices, chronic wasting disease in US white-tailed deer (Odocoileus virginianus) continues to expand geographically. Herein, we perform the largest genome-wide association analysis to date for chronic wasting disease (n = 412 chronic wasting disease-positive; n = 758 chronic wasting disease-nondetect) using a custom Affymetrix Axiom single-nucleotide polymorphism array (n = 121,010 single-nucleotide polymorphisms), and confirm that differential susceptibility to chronic wasting disease is a highly heritable (h2= 0.611 ± 0.056) polygenic trait in farmed US white-tailed deer, but with greater trait complexity than previously appreciated. We also confirm PRNP codon 96 (G96S) as having the largest-effects on risk (P ≤ 3.19E-08; phenotypic variance explained ≥ 0.025) across 3 US regions (Northeast, Midwest, South). However, 20 chronic wasting disease-positive white-tailed deer possessing codon 96SS genotypes were also observed, including one that was lymph node and obex positive. Beyond PRNP, we also detected 23 significant single-nucleotide polymorphisms (P-value ≤ 5E-05) implicating ≥24 positional candidate genes; many of which have been directly implicated in Parkinson's, Alzheimer's and prion diseases. Genotype-by-environment interaction genome-wide association analysis revealed a single-nucleotide polymorphism in the lysosomal enzyme gene ARSB as having the most significant regional heterogeneity of effects on chronic wasting disease (P ≤ 3.20E-06); with increasing copy number of the minor allele increasing susceptibility to chronic wasting disease in the Northeast and Midwest; but with opposite effects in the South. In addition to ARSB, 38 significant genotype-by-environment single-nucleotide polymorphisms (P-value ≤ 5E-05) were also detected, thereby implicating ≥ 36 positional candidate genes; the majority of which have also been associated with aspects of Parkinson's, Alzheimer's, and prion diseases.
Topics: Animals; Alzheimer Disease; Codon; Deer; Gene-Environment Interaction; Genome-Wide Association Study; Genotype; Parkinson Disease; Prion Diseases; Wasting Disease, Chronic; Polymorphism, Single Nucleotide
PubMed: 35536181
DOI: 10.1093/g3journal/jkac109 -
The Journal of Neuroscience : the... Mar 2009The role of the nucleus retroambiguus (NRA) in the context of respiration control has been subject of debate for considerable time. To solve this problem, we chemically...
The role of the nucleus retroambiguus (NRA) in the context of respiration control has been subject of debate for considerable time. To solve this problem, we chemically (using d, l-homocysteic acid) stimulated the NRA in unanesthetized precollicularly decerebrated cats and studied the respiratory effect via simultaneous measurement of tracheal pressure and electromyograms of diaphragm, internal intercostal (IIC), cricothyroid (CT), and external oblique abdominal (EO) muscles. NRA-stimulation 0-1 mm caudal to the obex resulted in recruitment of IIC muscle and reduction in respiratory frequency. NRA-stimulation 1-3 mm caudal to the obex produced vocalization along with CT activation and slight increase in tracheal pressure, but no change in respiratory frequency. NRA-stimulation 3-5 mm caudal to the obex produced CT muscle activation and an increase in respiratory frequency, but no vocalization. NRA-stimulation 5-8 mm caudal to the obex produced EO muscle activation and reduction in respiratory frequency. A change to the inspiratory effort was never observed, regardless of which NRA part was stimulated. The results demonstrate that NRA does not control eupneic inspiration but consists of topographically separate groups of premotor interneurons each producing detailed motor actions. These motor activities have in common that they require changes to eupneic breathing. Different combination of activation of these premotor neurons determines the final outcome, e.g., vocalization, vomiting, coughing, sneezing, mating posture, or child delivery. Higher brainstem regions such as the midbrain periaqueductal gray (PAG) decides which combination of NRA neurons are excited. In simple terms, the NRA is the piano, the PAG one of the piano players.
Topics: Abdominal Muscles; Animals; Cats; Decerebrate State; Diaphragm; Electromyography; Homocysteine; Inhalation; Intercostal Muscles; Laryngeal Muscles; Medulla Oblongata; Microinjections; Periaqueductal Gray; Pressure; Respiration; Trachea; Vocalization, Animal
PubMed: 19321779
DOI: 10.1523/JNEUROSCI.0607-09.2009