Simultaneous double gastrojejunostomy for afferent and efferent limb syndromes.
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ABSTRACT:
SUBMITTER: Ichkhanian Y
PROVIDER: S-EPMC7332759 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:IntroductionThe lateral habenula (LHb) is an epithalamic nucleus associated with negative valence and affective disorders. It receives input via the stria medullaris (SM) and sends output via the fasciculus retroflexus (FR). Here, we use tractography to reconstruct and characterize this pathway.MethodsMulti-shell human diffusion magnetic resonance imaging (dMRI) data was obtained from the human connectome project (HCP) (n = 20, 10 males) and from healthy controls (n = 10, 6 males) scanned at our institution. We generated LHb afferents and efferents using probabilistic tractography by selecting the pallidum as the seed region and the ventral tegmental area as the output target.ResultsWe were able to reconstruct the intended streamlines in all individuals from the HCP dataset and our dataset. Our technique also aided in identification of the LHb. In right-handed individuals, the streamlines were significantly more numerous in the left hemisphere (mean ratio 1.59 ± 0.09, p = 0.04). In left-handed individuals, there was no hemispheric asymmetry on average (mean ratio 1.00 ± 0.09, p = 1.0). Additionally, these streamlines were significantly more numerous in females than in males (619.9 ± 159.7 vs. 225.9 ± 66.03, p = 0.04).ConclusionWe developed a method to reconstruct the SM and FR without manual identification of the LHb. This technique enables targeting of these fiber tracts as well as the LHb. Furthermore, we have demonstrated that there are sex and hemispheric differences in streamline number. These findings may have therapeutic implications and warrant further investigation.
| S-EPMC9243380 | biostudies-literature
Project description:Renal sympathetic denervation (RDNx) has emerged as a novel therapy for hypertension; however, the therapeutic mechanisms remain unclear. Efferent renal sympathetic nerve activity has recently been implicated in trafficking renal inflammatory immune cells and inflammatory chemokine and cytokine release. Several of these inflammatory mediators are known to activate or sensitize afferent nerves. This study aimed to elucidate the roles of efferent and afferent renal nerves in renal inflammation and hypertension in the deoxycorticosterone acetate (DOCA) salt rat model. Uninephrectomized male Sprague-Dawley rats (275-300 g) underwent afferent-selective RDNx (n=10), total RDNx (n=10), or Sham (n=10) and were instrumented for the measurement of mean arterial pressure and heart rate by radiotelemetry. Rats received 100-mg DOCA (SC) and 0.9% saline for 21 days. Resting afferent renal nerve activity in DOCA and vehicle animals was measured after the treatment protocol. Renal tissue inflammation was assessed by renal cytokine content and T-cell infiltration and activation. Resting afferent renal nerve activity, expressed as a percent of peak afferent nerve activity, was substantially increased in DOCA than in vehicle (35.8±4.4 versus 15.3±2.8 %Amax). The DOCA-Sham hypertension (132±12 mm Hg) was attenuated by ≈50% in both total RDNx (111±8 mm Hg) and afferent-selective RDNx (117±5 mm Hg) groups. Renal inflammation induced by DOCA salt was attenuated by total RDNx and unaffected by afferent-selective RDNx. These data suggest that afferent renal nerve activity may mediate the hypertensive response to DOCA salt, but inflammation may be mediated primarily by efferent renal sympathetic nerve activity. Also, resting afferent renal nerve activity is elevated in DOCA salt rats, which may highlight a crucial neural mechanism in the development and maintenance of hypertension.
| S-EPMC5159336 | biostudies-literature
Project description:Acetylcholine is the major neurotransmitter of the olivocochlear efferent system, which provides feedback to cochlear hair cells and sensory neurons. To study the role of cochlear muscarinic receptors, we studied receptor localization with immunohistochemistry and reverse transcription-PCR and measured olivocochlear function, cochlear responses, and histopathology in mice with targeted deletion of each of the five receptor subtypes. M2, M4, and M5 were detected in microdissected immature (postnatal days 10-13) inner hair cells and spiral ganglion cells but not outer hair cells. In the adult (6 weeks), the same transcripts were found in microdissected organ of Corti and spiral ganglion samples. M2 protein was found, by immunohistochemistry, in olivocochlear fibers in both outer and inner hair cell areas. M3 mRNA was amplified only from whole cochleas, and M1 message was never seen in wild-type ears. Auditory brainstem responses (ABRs) and distortion product otoacoustic emissions (DPOAEs) were unaffected by loss of Gq-coupled receptors (M1, M3, or M5), as were shock-evoked olivocochlear effects and vulnerability to acoustic injury. In contrast, loss of Gi-coupled receptors (M2 and/or M4) decreased neural responses without affecting DPOAEs (at low frequencies). This phenotype and the expression pattern are consistent with excitatory muscarinic signaling in cochlear sensory neurons. At high frequencies, both ABRs and DPOAEs were attenuated by loss of M2 and/or M4, and the vulnerability to acoustic injury was dramatically decreased. This aspect of the phenotype and the expression pattern are consistent with a presynaptic role for muscarinic autoreceptors in decreasing ACh release from olivocochlear terminals during high-level acoustic stimulation and suggest that muscarinic antagonists could enhance the resistance of the inner ear to noise-induced hearing loss.
| S-EPMC3332094 | biostudies-literature
Project description:The axonal projections and synaptic input of the C1 adrenergic neurons of the rostral ventrolateral medulla (VLM) were examined using transgenic dopamine-beta hydroxylase Cre mice and modified rabies virus. Cre-dependent viral vectors expressing TVA (receptor for envelopeA) and rabies glycoprotein were injected into the left VLM. EnvelopeA-pseudotyped rabies-EGFP glycoprotein-deficient virus (rabies-EGFP) was injected 4-6 weeks later in either thoracic spinal cord (SC) or hypothalamus. TVA immunoreactivity was detected almost exclusively (95 %) in VLM C1 neurons. In mice with SC injections of rabies-EGFP, starter cells (expressing TVA + EGFP) were found at the rostral end of the VLM; in mice with hypothalamic injections starter C1 cells were located more caudally. C1 neurons innervating SC or hypothalamus had other terminal fields in common (e.g., dorsal vagal complex, locus coeruleus, raphe pallidus and periaqueductal gray matter). Putative inputs to C1 cells with SC or hypothalamic projections originated from the same brain regions, especially the lower brainstem reticular core from spinomedullary border to rostral pons. Putative input neurons to C1 cells were also observed in the nucleus of the solitary tract, caudal VLM, caudal spinal trigeminal nucleus, cerebellum, periaqueductal gray matter and inferior and superior colliculi. In sum, regardless of whether they innervate SC or hypothalamus, VLM C1 neurons receive input from the same general brain regions. One interpretation is that many types of somatic or internal stimuli recruit these neurons en bloc to produce a stereotyped acute stress response with sympathetic, parasympathetic, vigilance and neuroendocrine components.
| S-EPMC4864159 | biostudies-literature
Project description:BackgroundDifferent classes of unmyelinated nerve fibers appear to exhibit distinct conductive properties. We sought a criterion based on conduction properties for distinguishing sympathetic efferents and unmyelinated, primary afferents in peripheral nerves.Methodology/principal findingsIn anesthetized monkey, centrifugal or centripetal recordings were made from single unmyelinated nerve fibers in the peroneal or sural nerve, and electrical stimuli were applied to either the sciatic nerve or the cutaneous nerve endings, respectively. In centrifugal recordings, electrical stimulation at the sympathetic chain and dorsal root was used to determine the fiber's origin. In centrifugal recordings, sympathetic fibers exhibited absolute speeding of conduction to a single pair of electrical stimuli separated by 50 ms; the second action potential was conducted faster (0.61 0.16%) than the first unconditioned action potential. This was never observed in primary afferents. Following 2 Hz stimulation (3 min), activity-dependent slowing of conduction in the sympathetics (8.6 0.5%) was greater than in one afferent group (6.7 0.5%) but substantially less than in a second afferent group (29.4 1.9%). In centripetal recordings, most mechanically-insensitive fibers also exhibited absolute speeding to twin pulse stimulation. The subset that did not show this absolute speeding was responsive to chemical stimuli (histamine, capsaicin) and likely consists of mechanically-insensitive afferents. During repetitive twin pulse stimulation, mechanosensitive afferents developed speeding, and speeding in sympathetic fibers increased.Conclusions/significanceThe presence of absolute speeding provides a criterion by which sympathetic efferents can be differentiated from primary afferents. The differences in conduction properties between sympathetics and afferents likely reflect differential expression of voltage-sensitive ion channels.
| S-EPMC2816714 | biostudies-literature
Project description:Vision, which requires extensive neural involvement, is often impaired in Alzheimer’s disease (AD). Over the last few decades, accumulating evidence has shown that various visual functions and structures are compromised in Alzheimer’s dementia and when measured can detect those with dementia from those with normal aging. These visual changes involve both the afferent and efferent parts of the visual system, which correspond to the sensory and eye movement aspects of vision, respectively. There are fewer, but a growing number of studies, that focus on the detection of predementia stages. Visual biomarkers that detect these stages are paramount in the development of successful disease-modifying therapies by identifying appropriate research participants and in identifying those who would receive future therapies. This review provides a summary and update on common afferent and efferent visual markers of AD with a focus on mild cognitive impairment (MCI) and preclinical disease detection. We further propose future directions in this area. Given the ease of performing visual tests, the accessibility of the eye, and advances in ocular technology, visual measures have the potential to be effective, practical, and non-invasive biomarkers of AD.
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Project description:Peripheral nerve injury impairs motor and sensory function in humans, and its functional recovery largely depends on the axonal outgrowth required for the accurate reinnervation of appropriate targets. To better understand how motor and sensory nerve fibres select their terminal pathways, an unbiased cDNA microarray analysis was conducted to examine differential gene expression patterns in peripheral efferent and afferent fibres at different developmental stages in mice. Gene ontology (GO) and Kyoto Enrichment of Genes and Genomes (KEGG) analyses revealed common and distinct features of enrichment for differentially expressed genes during motor and sensory nerve fibre development. Ingenuity Pathway Analysis (IPA) further indicated that the key differentially expressed genes were associated with trans-synaptic neurexin-neuroligin signalling components and a variety of gamma-aminobutyric acid (GABA) receptors. The aim of this study was to generate a framework of gene networks regulated during motor and sensory neuron differentiation/maturation. These data may provide new clues regarding the underlying cellular and molecular mechanisms that determine the intrinsic capacity of neurons to regenerate after peripheral nerve injury. Our findings may thus facilitate further development of a potential intervention to manipulate the therapeutic efficiency of peripheral nerve repair in the clinic.
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Project description:In the present study, an unbiased cDNA microarray analysis was carried out to examine differential gene expression patterns in both efferent and afferent nerve fibres at different developmental stages in mice. The aim of this study was to provide a framework for the integrated analysis of gene regulatory networks during peripheral motor and sensory neuron differentiation/maturation.
2018-05-01 | GSE113820 | GEO
Project description:Accumulation of excess glutamate plays a central role in eliciting the pathological events that follow intensely loud noise exposures and ischemia-reperfusion injury. Glutamate excitotoxicity has been characterized in cochlear nerve terminals, but much less is known about whether excess glutamate signaling also contributes to pathological changes in sensory hair cells. I therefore examined whether glutamate excitotoxicity damages hair cells in zebrafish larvae exposed to drugs that mimic excitotoxic trauma. Exposure to ionotropic glutamate receptor (iGluR) agonists, kainic acid (KA) or N-methyl-D-aspartate (NMDA), contributed to significant, progressive hair cell loss in zebrafish lateral-line organs. To examine whether hair-cell loss was a secondary effect of excitotoxic damage to innervating neurons, I exposed neurog1a morphants-fish whose hair-cell organs are devoid of afferent and efferent innervation-to KA or NMDA. Significant, dose-dependent hair-cell loss occurred in neurog1a morphants exposed to either agonist, and the loss was comparable to wild-type siblings. A survey of iGluR gene expression revealed AMPA-, Kainate-, and NMDA-type subunits are expressed in zebrafish hair cells. Finally, hair cells exposed to KA or NMDA appear to undergo apoptotic cell death. Cumulatively, these data reveal that excess glutamate signaling through iGluRs induces hair-cell death independent of damage to postsynaptic terminals.
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Project description:Hyperactive inflammatory responses following cancer initiation have led to cancer being described as a 'wound that never heals'. These inflammatory responses elicit signals via NF?B leading to IL-6 production, and IL-6 in turn has been shown to induce epithelial to mesenchymal transition in breast cancer cells in vitro, implicating a role for this cytokine in cancer cell invasion. We previously have shown that conditioned medium derived from cancer-associated fibroblasts induced an Epithelial to Mesenchymal transition (EMT) in PMC42-LA breast cancer cells and we have now identify IL-6 as present in this medium. We further show that IL-6 is expressed approximately 100 fold higher in a cancer-associated fibroblast line compared to normal fibroblasts. Comparison of mouse-specific (stroma) and human-specific (tumor) IL-6 mRNA expression from MCF-7, MDA MB 468 and MDA MB 231 xenografts also indicated the stroma rather than tumor as a significantly higher source of IL-6 expression. Mast cells (MCs) feature in inflammatory cancer-associated stroma, and activated MCs secrete IL-6. We observed a higher MC index (average number of mast cells per xenograft section/average tumor size) in MDA MB 468 compared to MDA MB 231 xenografts, where all MC were observed to be active (degranulating). This higher MC index correlated with greater mouse-specific IL-6 expression in the MDA MB 468 xenografts, implicating MC as an important source of stromal IL-6. Furthermore, immunohistochemistry on these xenografts for pSTAT3, which lies downstream of the IL-6 receptor indicated frequent correlations between pSTAT3 and mast cell positive cells. Analysis of publically available databases for IL-6 expression in patient tissue revealed higher IL-6 in laser capture microdissected stroma compared to adjacent tissue epithelium from patients with inflammatory breast cancer (IBC) and invasive non-inflammatory breast cancer (non-IBC) and we show that IL-6 expression was significantly higher in Basal versus Luminal molecular/phenotypic groupings of breast cancer cell lines. Finally, we discuss how afferent and efferent IL-6 pathways may participate in a positive feedback cycle to dictate tumor progression.
| S-EPMC3343200 | biostudies-literature