scholarly journals Variability Index of Optic Nerve Diameter with Hyperosmolar Therapy in Patients with Acute Neurological Injury

2021 ◽  
Vol 11 (4) ◽  
Author(s):  
Lleny Bocanegra Flores
Keyword(s):  
Optic Nerve ◽  
Neurological Injury ◽  
Hyperosmolar Therapy ◽  
Optic Nerve Diameter ◽  
Variability Index

Cd(2+)-induced injury in CNS white matter

1996 ◽  
Vol 76 (5) ◽  
pp. 3264-3273 ◽  
Author(s):  
R. Fern ◽  
J. A. Black ◽  
B. R. Ransom ◽  
S. G. Waxman
Keyword(s):  
White Matter ◽  
Optic Nerve ◽  
Mitochondrial Respiration ◽  
Time Course ◽  
White Matter Injury ◽  
Neurological Injury ◽  
Antimycin A ◽  
Optic Nerves ◽  
Voltage Gated ◽  
Ca2 Channels

1. The affect of extracellular Cd2+ on CNS white matter was studied using an isolated rat optic nerve preparation. A 100-min exposure to 200 microM Cd2+ reduced the area of the compound action potential (CAP) recorded from the optic nerve to 32.6 +/- 3.8% (mean +/- SE) of the preexposure area, compared with a reduction to 74.9 +/- 2.9% after 100 min in control conditions (P > 0.001). This CAP reduction was not reversed after 120 min of reperfusion with Cd(2+)-free solution, or by perfusion with Cd2+ chelators. 2. Cd(2+)-induced CAP loss occurred in the absence of extracellular Ca2+. Increasing extracellular Ca2+ concentration to 16 mM, however, prevented Cd(2+)-induced CAP loss. Once evident, Cd(2+)-induced CAP reduction could not subsequently be reversed by addition of 16 mM Ca2+. 3. Low concentrations of Cd2+ (60 microM) did not significantly reduce CAP area. This concentration of Cd2+ combined with high extracellular K+ (30 mM) caused CAP loss that was blocked by 10 microM nifedipine, an antagonist of L-type voltage-gated Ca2+ channels. 4. Treatment with pharmacological inhibitors of membrane proteins known to be inhibited by Cd2+ did not affect the CAP. These included inhibitors of voltage-gated Ca2+ channels, Ca(2+)-activated K+ channels, Ca(2+)-ATPase and the Na+/Ca2+ exchanger. 5. Treatment with pharmacological agents that inhibit calmodulin or disrupt tubulin, two intracellular proteins affected by Cd2+, did not affect CAP area. 6. The effect of Cd2+ was not prevented by pretreatment with (+)-cyanidanol-3, an agent that prevents Cd(2+)-induced lipid peroxidation. 7. Treatment with antimycin A, a inhibitor of mitochondrial respiration, resulted in irreversible CAP reduction with a time course and extent similar to that produced by 200 microM Cd2+. Cd(2+)-induced CAP reduction was prevented by 1 mM cysteine, which prevents Cd(2+)-induced disruption of mitochondrial respiration. 8. The ultrastructure of optic nerves exposed to 200 microM Cd2+ for 100 min was characterized by swollen mitochondria with disrupted cristae and dissolution of microtubules, which were replaced by flocculent debris. Occasional regions of axonal swelling and empty spaces beneath the myelin also were found. Qualitatively similar changes in mitochondria and cytoskeletal elements were found in optic nerves exposed to antimycin A for 100 min. Astrocytes also displayed disrupted mitochondria and had an electron-lucent appearance under both conditions. 9. The neurological injury produced by exposure to Cd2+ is characterized by lesions of CNS white matter. Our results indicate that Cd(2+)-induced white matter injury in vitro results largely from disruption of mitochondrial respiration after Cd2+ influx through routes that include voltage-gated Ca2+ channels.

Ultrasonic biometry of the optic nerve diameter

Orbit ◽  
1986 ◽  
Vol 5 (3) ◽  
pp. 201-205
Author(s):  
Sadanao Tane ◽  
Jun Horikoshi
Keyword(s):  
Optic Nerve ◽  
Optic Nerve Diameter

scholarly journals Influence of retrobulbar neuritis and papillitis on echographically measured optic nerve diameter

2010 ◽  
Vol 67 (1) ◽  
pp. 32-35 ◽  
Author(s):  
Ivan Stefanovic ◽  
Milos Jovanovic ◽  
Bojana Dacic-Krnjaja ◽  
Dragan Veselinovic ◽  
Predrag Jovanovic
Keyword(s):  
Visual Acuity ◽  
Optic Nerve ◽  
Optic Neuritis ◽  
Significant Negative Correlation ◽  
Optic Disk ◽  
Partial Loss ◽  
Retrobulbar Neuritis ◽  
Optic Nerve Diameter ◽  
Ophthalmologic Examination ◽  
Retrobulbar Optic Neuritis

Background/Aim. Retrobulbar (optic) neuritis is inflammation of the optic nerve that may cause a complete or partial loss of vision. This inflammation can affect a part of the nerve within the eyeball (neuropapillitis) or a part of the nerve behind the eyeball (retrobulbar neuritis). The aim of this study was to establish whether there is a correlation between the diameter of a retrobulbar part of the optic nerve and either visual acuity, prominence of the optic disk (papillitis), or nature of the neuritis (papillitis or retrobulbar). Methods. We tested 23 patients with retrobulbar neuritis and papillitis. In addition to a complete ophthalmologic examination, the diameter of retrobulbar region of the optic nerve was measured by the B-scan method. Following this, the 30-degree test was carried out. Results. We found an increased thickness of the retrobulbar region in 22 patients and different responses to the 30-degree test, as well as a statistically significant negative correlation between the thickness of retrobulbar part of the optic nerve and visual acuity. Conclusion. The retrobulbar part of the optic nerve is thicker in 94% of the patients with retrobulbar neuritis and in all the patients with papillitis. There is a correlation between the reduction of visual acuity and thickening of a retrobulbar part.

Sonographic Optic Nerve Diameter and Clinical Biomarkers in Patients With Poorly Controlled Diabetes: A Comparative Analysis With Nondiabetic Subjects

2021 ◽  
pp. 875647932110441
Author(s):  
Benjamin Effiong Udoh ◽  
Akwa Egom Erim ◽  
Bassey E. Archibong ◽  
Samson O. Paulinus ◽  
Basil Chukwuma Ezeokpo ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Hemoglobin A1c ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Lipid Profiles ◽  
Imaging Biomarker ◽  
Eyes Closed ◽  
Clinical Biomarkers ◽  
Array Transducer ◽  
Optic Nerve Diameter

Objective: The study assessed optic nerve diameter (OND) and clinical biomarkers in patients with poorly controlled diabetes compared with healthy nondiabetic volunteers. Materials and Methods: There were 1320 adult participants recruited to the study. The cohort was divided into 600 Type 2 diabetic (DM II) patients and 720 apparently healthy, nondiabetic volunteers. The OND was measured using a high-resolution dedicated ultrasound device (Sonoace 5500; Medicol, Medison, Miami, FL, USA) with a 10-MHz linear array transducer. Subjects were examined in a supine position with their eyes closed. Three measurements of the OND were taken and the average recorded. Hemoglobin A1c concentration and lipid profiles were determined using Bio-Rad Diamat analyzer (Bio-Rad, Hercules, CA). Body mass index and age were matched for both cohorts for comparativeness. Results: The mean OND of the DM II patients was 3.10 ± 0.14 mm (range of 2.6–4.0 mm), which was significantly ( P < .05) lower than the control volunteers (4.22 ± 0.15 mm). The OND demonstrated a negative significant correlation with HA1c, duration of diabetes and low-density lipoprotein cholesterol level ( P < .05). Lipid profiles, blood urea, serum creatinine, and hemoglobin A1c showed statistical difference between diabetics and control subjects. Conclusion: Poorly controlled DM II patients may have significantly narrower OND than nondiabetic patients. This imaging biomarker has the potential to transform visual care for DM II patients.

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