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International Journal of Molecular... Jun 2023BDNF is a neurotrophin family member implicated in many different neuronal functions, from neuronal survival during development to synaptic plasticity associated with...
BDNF is a neurotrophin family member implicated in many different neuronal functions, from neuronal survival during development to synaptic plasticity associated with processes of learning and memory. Its presence in the oculomotor system has previously been demonstrated, as it regulates afferent composition of extraocular motoneurons and their firing pattern. Moreover, BDNF expression increases after extraocular motoneuron partial deafferentation, in parallel with terminal axon sprouting from the remaining axons. To elucidate whether BDNF could play an active role in this process, we performed partial deafferentation of the medial rectus motoneurons through transection of one of the two main afferents, that is, the ascending tract of Deiters, and injected BDNF into the motoneuron target muscle, the medial rectus. Furthermore, to check whether BDNF could stimulate axon sprouting without lesions, we performed the same experiment without any lesions. Axon terminal sprouting was assessed by calretinin immunostaining, which specifically labels the remaining afferent system on medial rectus motoneurons, the abducens internuclear neurons. The results presented herein show that exogenous BDNF stimulated terminal axon growth, allowing the total recovery of synaptic coverage around the motoneuron somata. Moreover, calretinin staining in the neuropil exceeded that present in the control situation. Thus, BDNF could also stimulate axonal sprouting in the neuropil of intact animals. These results point to an active role of BDNF in plastic adaptations that take place after partial deafferentation.
Topics: Animals; Calbindin 2; Brain-Derived Neurotrophic Factor; Abducens Nerve; Motor Neurons; Axons
PubMed: 37445838
DOI: 10.3390/ijms241310660 -
Nature Communications Jul 2023Antibiotic resistance ABC-Fs (ARE ABC-Fs) are translation factors that provide resistance against clinically important ribosome-targeting antibiotics which are...
Antibiotic resistance ABC-Fs (ARE ABC-Fs) are translation factors that provide resistance against clinically important ribosome-targeting antibiotics which are proliferating among pathogens. Here, we combine genetic and structural approaches to determine the regulation of streptococcal ARE ABC-F gene msrD in response to macrolide exposure. We show that binding of cladinose-containing macrolides to the ribosome prompts insertion of the leader peptide MsrDL into a crevice of the ribosomal exit tunnel, which is conserved throughout bacteria and eukaryotes. This leads to a local rearrangement of the 23 S rRNA that prevents peptide bond formation and accommodation of release factors. The stalled ribosome obstructs the formation of a Rho-independent terminator structure that prevents msrD transcriptional attenuation. Erythromycin induction of msrD expression via MsrDL, is suppressed by ectopic expression of mrsD, but not by mutants which do not provide antibiotic resistance, showing correlation between MsrD function in antibiotic resistance and its action on this stalled complex.
Topics: Humans; Anti-Bacterial Agents; Drug Resistance, Bacterial; Macrolides; Abducens Nerve Diseases; Accommodation, Ocular
PubMed: 37393329
DOI: 10.1038/s41467-023-39553-8 -
Ear, Nose, & Throat Journal Jun 2023
The Location of the Abducens Nucleus and Facial Nerve Fascicle: Letter to the Editor Regarding the Article "Association Between Multiple Sclerosis and the Symptoms of Vertigo and Facial Nerve Palsy".
PubMed: 37365815
DOI: 10.1177/01455613231184149 -
Neurologia Medico-chirurgica Aug 2023Flow diverter (FD) stenting is expected to improve cranial nerve symptoms caused by aneurysms via the theoretical reduction of the mass effect by promoting spontaneous...
Flow diverter (FD) stenting is expected to improve cranial nerve symptoms caused by aneurysms via the theoretical reduction of the mass effect by promoting spontaneous thrombosis through the flow diversion effect. However, the factors involved in symptom improvement after treatment remain unclear. This study was performed to identify factors for symptom improvement after FD stenting and the symptom improvement rate of each impaired cranial nerve. We retrospectively evaluated 33 patients who underwent FD stenting for symptomatic internal carotid artery aneurysms at our institution from January 2016 to June 2021. Twenty-three (69.7%) patients had resolved or improved symptoms after 1 year of treatment. The optic nerve was affected in 12 patients; the oculomotor nerve, in 16; the trigeminal nerve, in 2; and the abducens nerve, in 13. There was no statistically significant difference in the symptom improvement rate of each impaired cranial nerve. The patients were classified into the improved and nonimproved groups based on their symptoms after 1 year of treatment, and the factors related to the symptoms were analyzed. The time from onset to treatment was significantly shorter in the improved group than in the nonimproved group (197.1 and 800 days, respectively; p = 0.023). There were no significant differences in age, aneurysm diameter, adjunctive coil embolization, partial thrombosis, change in mass diameter on magnetic resonance imaging, or aneurysm occlusion rate on angiography between the two groups. These results suggest that early treatment after the onset of aneurysm-induced cranial neuropathies increases the likelihood of symptom improvement.
Topics: Humans; Carotid Artery, Internal; Intracranial Aneurysm; Treatment Outcome; Retrospective Studies; Embolization, Therapeutic; Stents; Carotid Artery Diseases; Endovascular Procedures
PubMed: 37286482
DOI: 10.2176/jns-nmc.2022-0389 -
Indian Journal of Ophthalmology May 2023We report two adult cases of abducens nerve palsy presenting immediately (within weeks) after they received the first dose of Covishield vaccination. Magnetic resonance...
We report two adult cases of abducens nerve palsy presenting immediately (within weeks) after they received the first dose of Covishield vaccination. Magnetic resonance imaging (MRI) of the brain obtained after the onset of diplopia demonstrated demyelinating changes. The patients had associated systemic symptoms. Post-vaccination demyelination typically known as acute disseminated encephalomyelitis (ADEM) associated with several vaccines is more common in children. Although the mechanism of the nerve palsy remains unclear, it is suspected to be related to the post-vaccine neuroinflammatory syndrome. Cranial nerve palsies and ADEM-like presentations may represent part of the neurologic spectrum following COVID-vaccination in adults, and ophthalmologists should be aware of these sequelae. Although cases of sixth nerve palsy following COVID vaccination are already reported, associated MRI changes have not been reported from India.
Topics: Adult; Child; Humans; Encephalomyelitis, Acute Disseminated; COVID-19 Vaccines; ChAdOx1 nCoV-19; COVID-19; Abducens Nerve Diseases; Vaccination
PubMed: 37202971
DOI: 10.4103/ijo.IJO_1778_22 -
International Journal of Surgery Case... Jun 2023Orbital Apex Syndrome (OAS) are characterized by multiple symptoms, such as impaired eye movement, periorbital pain, and visual disturbance. AS symptoms may be caused by...
INTRODUCTION AND IMPORTANCE
Orbital Apex Syndrome (OAS) are characterized by multiple symptoms, such as impaired eye movement, periorbital pain, and visual disturbance. AS symptoms may be caused by inflammation, infection, neoplasm, or a vascular lesion, potentially involving a variety of nerves, such as the optic, oculomotor, trochlear or abducens, or the ophthalmic branch of the trigeminal nerve. However, OAS caused by invasive aspergillosis in post-COVID patient is a very rare phenomenon.
CASE PRESENTATION
A 43-year-old male with a history of diabetes mellitus and hypertension who had recently recovered from a COVID-19 infection developed blurred vision on the left eye field, followed by impaired vision on left eye field for 2 months then retro-orbital pain for a further 3 months. The blurring of vision and headache developed soon after recovering from COVID-19 and was progressive in left eye field. He denied any symptoms of diplopia, scalp tenderness, weight loss, or jaw claudication. The patient was treated with IV methylprednisolone for 3 days with as diagnosis of optic neuritis, followed by a course of oral corticosteroid therapy (prednisolone, starting at 60 mg for 2 days and then tapered for 1 month), which produced transient relief of symptoms that recurred when prednisone was discontinued. Then repeat MRI was perform with no evidence of lesion; treated again in a line of optic neuritis and symptoms relief transiently. After reoccurrence of symptoms repeat MRI was perform which showed a heterogeneously enhancing intermediate signal intensity lesion in the left orbital apex. The lesion was encasing and compressing the left optic nerve, without abnormal signal intensity or contrast enhancement within the left optic nerve either proximal or distal to the lesion. The lesion was contiguous with focal asymmetric enhancement in the left cavernous sinus. No inflammatory changes were seen in the orbital fat.
CLINICAL DISCUSSION
OAS due to invasive fungal infection is uncommon and most often caused by Mucorales spp., or Aspergillus, particularly in those with immunocompromising conditions or uncontrolled diabetes mellitus. In OAS due to Aspergillosis urgent treatment is necessary to avoid complications such as complete vision loss and cavernous sinus thrombosis.
CONCLUSION
OASs, represent a heterogenous group of disorders that results from a number of etiologies. OAS in a background of COVID-19 pandemic can be due to invasive Aspergillus infection as in our patient without any systemic illness and lead to miss diagnosis and delay in proper treatment.
PubMed: 37196477
DOI: 10.1016/j.ijscr.2023.108306 -
Cureus Apr 2023The patient was a 46-year-old woman who presented with right sixth cranial nerve (CN VI) palsy following severe head trauma secondary to a motor vehicle collision one...
The patient was a 46-year-old woman who presented with right sixth cranial nerve (CN VI) palsy following severe head trauma secondary to a motor vehicle collision one month prior. In this case report, we aim to add to the literature an additional example of unilateral CN VI avulsion as visualized by MRI secondary to head trauma. 3D T2 MRI was used to visualize the CN VI avulsion. CT was also used in the evaluation of head trauma. In our view, the force trajectory of the patient's impact with the vehicle dashboard, as evidenced by the right occipital lobe fracture, explains the etiology of the unilateral right CN VI avulsion. The combination of clinical and imaging findings was central to the analysis of this case.
PubMed: 37187660
DOI: 10.7759/cureus.37486 -
BMC Endocrine Disorders May 2023Some patients develop immunoglobulin G4 (IgG4)-related hypophysitis associated with systemic diseases. More than 30 cases of IgG4-related hypophysitis have been...
BACKGROUND
Some patients develop immunoglobulin G4 (IgG4)-related hypophysitis associated with systemic diseases. More than 30 cases of IgG4-related hypophysitis have been reported. However, biopsy has rarely been performed in these patients, and none have had an associated pituitary neuroendocrine tumor (PitNET). We present a case of concurrent IgG4-related hypophysitis and PitNET.
CASE PRESENTATION
A 56-year-old Japanese man arrived at the hospital with visual impairment, bitemporal hemianopia, and right abducens nerve palsy. Magnetic resonance imaging revealed pituitary body and stalk swelling as well as a small poorly enhanced right anterior lobe mass. Laboratory and loading test results suggested hypopituitarism. Because IgG4 level was elevated, a systemic examination was performed; multiple nodules were found in both lung fields. The diagnosis was based on an endoscopic transnasal biopsy of the pituitary gland. A histopathological examination revealed a marked infiltration of plasma cells into the pituitary gland, which was strongly positive for IgG4. The histological features of the resected tumor were consistent with those of gonadotroph PitNET, which was immunohistochemically positive for follicle-stimulating hormone-β and steroidogenic factor-1, and no plasma cell infiltration was observed. Based on the histopathological examination results, steroid therapy was initiated, which reduced pituitary gland size and serum IgG4 levels.
DISCUSSION AND CONCLUSIONS
This is the first reported case of IgG4-related hypophysitis with PitNET. Although no pathological findings indicating a relationship between the two conditions were found, we were able to preoperatively differentiate multiple lesions via detailed diagnostic imaging.
Topics: Male; Humans; Middle Aged; Autoimmune Hypophysitis; Gonadotrophs; Neuroendocrine Tumors; Pituitary Gland; Pituitary Diseases; Hypophysitis; Pituitary Neoplasms; Immunoglobulin G
PubMed: 37143052
DOI: 10.1186/s12902-023-01353-y -
The Indian Journal of Radiology &... Apr 2023The clivus is a midline anatomical structure in the central skull base. It is affected by a wide range of non-neoplastic, benign and malignant pathologies, some of which...
The clivus is a midline anatomical structure in the central skull base. It is affected by a wide range of non-neoplastic, benign and malignant pathologies, some of which typically affect the clivus because of its strategic location and embryological origins. Clival lesions may often be asymptomatic with occasional complaints like headache or cranial neuropathy in few. Cross-sectional imaging techniques, namely, computed tomographic scan and magnetic resonance imaging, thus, play a key role in approximating to the final diagnosis and estimating the disease extent. In this article, we highlight the important imaging features of various clival and paraclival pathologies to facilitate effective diagnosis, therapeutic planning, and management.
PubMed: 37123565
DOI: 10.1055/s-0043-1761183