Monorhinal and Birhinal Odor Processing in Humans: an fMRI investigation.

The olfactory nerve, also known as cranial nerve I, is known to have exclusive ipsilateral projections to primary olfactory cortical structures. It is still unclear whether these projections also correspond to functional pathways of odor processing. In an olfactory functional magnetic resonance imaging (fMRI) study of twenty young healthy subjects with a normal sense of smell, we tested whether nostril specific stimulation with phenyl ethyl alcohol (PEA), a pure olfactory stimulant, asymmetrically activates primary or secondary olfactory-related brain structures such as primary olfactory cortex, entorhinal cortex, and orbitofrontal cortex. The results indicated that without a challenging olfactory task, passive (no sniffing) and active (with sniffing) nostril-specific PEA stimulation did not produce asymmetrical fMRI activation in olfactory cortical structures.

Association of death or illness from COVID-19 among family and friends on vaccine uptake within four months of the Emergency Use Authorization. Findings from a national survey in the United States.

OBJECTIVE: To examine the relationship between knowing that a friend or family member became ill with, or died from, COVID-19 and receiving a vaccine dose within four months of the FDA's Emergency Use Authorization. METHODS: A national sample of 1,517 respondents were surveyed from April 7 to April 12, 2021, 1,193 of whom were eligible for the vaccine when the data were collected. RESULTS: Respondents who knew someone who became ill with COVID-19 (AOR = 2.32, 95 % CI 1.74-3.09) or knew someone who died (AOR = 2.29, 95 % CI 1.32-3.99) from COVID-19 were more likely to receive at least a single COVID-19 vaccine dose. CONCLUSION: Encouraging people to share their COVID-19 illness and bereavement experiences with their local network such as friends, families, social-networks and via social media might help increase vaccine uptake.

Prevalence of corneal astigmatism before cataract surgery in Western Indian Population.

BACKGROUND: The prevalence and nature of corneal astigmatism among cataract surgery candidates has not been well-documented in Indian population. The purpose of the study is to analyse prevalence and presentation patterns of corneal astigmatism (CA) in cataract surgery candidates. METHODS: Keratometric values were measured in patients before cataract extraction. Descriptive statistics of CA were analysed including the assessment with age ranges. RESULTS: Mean CA of 223 eyes of 223 patients [mean age 61 ± 10 years (range, 29-90 years)] was 0.88 ± 0.61 (95% CI, 0.80-0.96) with 27.8%, 51.1% and 21.1% having with the rule (WTR), against the rule (ATR) and oblique astigmatism (OBL) respectively. Between 40 and 50 years, ATR exceeds WTR and reaches 100% by 80 years. A trend of less negative CA was seen up to 60 years and then increases up to 90 years. CA was below 0.25 dioptre (D) in 17.5% of eyes, between 0.25 and 1.25 D in 63.7% and ≥1.50 D in 18.8% of eyes. CONCLUSIONS: Considering CA < 1.25 D in majority of cataract surgery candidates, it is preferable to perform inexpensive keratorefractive procedures rather expensive toric IOLs, especially in developing world.

Corneal infection by Pseudomonas stutzeri following excision of trigeminal nerve schwannoma.

A 25-year-old woman underwent intracranial surgery for trigeminal nerve schwannoma (TGNS) with persistent left-sided facial hypoaesthesia. Two months later, she developed a central corneal ulceration. Scraping of the corneal lesion revealed Gram-negative bacilli. Genus level identification was achieved using standard techniques and species level identification, revealing Pseudomonas stutzeri, was aided by a VITEK 2 compact system. Broad-spectrum fortified antibiotics were initially started followed by species-sensitive fortified antibiotics. Ocular surface toxicity developed a week later; this was managed with a non-fortified antibiotic. The epithelial defect healed in 3 weeks with subsequent corneal scar formation. Visual rehabilitation was achieved with deep anterior lamellar keratoplasty. Six months following surgery, the patient had a visual acuity of 20/40 with -1.25 170° -0.5 refractive correction and a clear graft. This case report, for the first time, highlights P. stutzeri, an aetiological agent of corneal ulcer following excision of TGNS and its successful management.

Persistent vertigo and dizziness after mild traumatic brain injury.

Vertigo, dizziness, and disequilibrium are common symptoms following concussion or mild traumatic brain injury (mTBI). Dizziness and vertigo may be the result of trauma to the peripheral vestibular system or the central nervous system, or, in some cases, may be due to anxiety, depression, or posttraumatic stress disorder; these mechanisms are not mutually exclusive. While most peripheral vestibular disorders can be identified by testing and examination, those without inner-ear causes that have persisting complaints of dizziness and motion sickness are more difficult to understand and to manage. Some of these patients exhibit features compatible with vestibular migraine and may be treated successfully with migraine-preventative medications. This paper reviews the nonotogenic causes of persisting dizziness, the possible mechanisms, and the pathophysiology, as a framework for patient management and for future research.

Comparison of efficacy of three surgical methods of conjunctival autograft fixation in the treatment of pterygium.

Our aim primarily was to compare the recurrence rate with three techniques of conjunctival fixation (suture versus fibrin glue versus autologous in situ blood coagulum) over bare sclera following pterygium excision. Ninety eyes of 90 patients with primary pterygium were randomly divided into three groups: group I (30 eyes) underwent autografting and fixation with 8-0 vicryl sutures, group II (30 eyes) with fibrin glue and group III (30 eyes) with autologous in situ blood coagulum. The patients were reviewed on 2nd day, weeks 1 and 4, and at every 3 months till 12 months after surgery. Rate of recurrence was similar (p = 0.585) across the three groups. Time taken for surgery for Group 1 was more as compared to group 2 (p < 0.001) and group 3 (p < 0.001). Also, group 2 cases took significantly more time as compared to group 3 (p < 0.001). Postoperative patient discomfort (foreign body sensation, epiphora, pain and irritation) was more in suture-assisted autografting as compared to the other two groups. However, at some points along the time line, patient discomfort was significantly more in group III as compared to group II. Complications like graft retraction, graft displacement and cyst formation were seen in a few patients but were not statistically significant across the three groups. All three techniques were found to be useful methods and were associated with similar rate of recurrence.

Ultrasonic pachymeter: a little different role.

BACKGROUND: Ultrasonic pachymeter, though primarily used in refractive surgery and in glaucoma evaluation, can evaluate and compare the change in corneal thickness following extracapsular cataract extraction (ECCE), small incision cataract surgery (SICS) and phacoemulsification. METHOD: Six hundred patients were included in study. Patients were divided into three groups. Group 1 (200 eyes), group 2 (200 eyes) and group 3 (200 eyes) underwent ECCE, SICS, and phacoemulsification, respectively. Corneal thickness was evaluated pre-operatively and postoperatively on day 1, day 2, day 7, day 15, and day 30 by ultrasonic pachymetry. RESULTS: Mean pre-operative corneal thickness in central, superior, inferior, nasal, and temporal quadrants is 525.35 ± 32.34 µm, 592.23 ± 35.39 µm, 595.66 ± 31.68 µm, 589.29 ± 38.07 µm, and 581.19 ± 42.31 µm, respectively. Postoperatively, a highly significant (P<0.01) increase in central corneal thickness was observed up to day 15 in ECCE, day 7 in SICS whereas it was up to day 2 in phacoemulsification. In superior quadrant, it is up to day 15 in ECCE and SICS whereas it is up to day 7 in phacoemulsification. In inferior quadrant, it was up to day 2 in all three techniques. In temporal quadrant, it is up to day 7 in ECCE and up to day 2 in SICS and phacoemulsification. In nasal quadrant, a highly significant (P<0.01) increase in corneal thickness was observed up to day 7 in ECCE and SICS whereas it was up to day 2 in phacoemulsification. CONCLUSION: Normal central corneal thickness is 525.35 ± 32.44 µm. At midperiphery, inferior cornea has maximum corneal thickness followed by superior, temporal, and nasal cornea. Postoperatively, pre-operative value of corneal thickness and visual rehabilitation is achieved earliest in phacoemulsifiaction followed by SICS and ECCE.

Light-induced translocation of Drosophila visual Arrestin2 depends on Rac2.

Photoreceptor cells are remarkable in their ability to adjust their sensitivity to light over a wide range of intensities. Rapid termination of the photoresponse is achieved in part by shuttling proteins in and out of the light-transducing compartment of the photoreceptor cells. One protein that undergoes light-dependent translocation is the rhodopsin regulatory protein arrestin. However, the mechanisms coupling rhodopsin to arrestin movement are poorly understood. Here we show that light-dependent shuttling of the major arrestin in Drosophila photoreceptor cells, Arrestin2 (Arr2), occurs independently of known elements of the phototransduction cascade. Disruptions of the trimeric G protein, phospholipase Cbeta, the TRP channel, or the Na(+)/Ca(2+) exchanger did not influence Arr2 localization. Rather, we found that loss of the small GTPase Rac2 severely impaired Arr2 movement and prolonged the termination of the photoresponse. Our findings demonstrate that light-induced translocation of Arr2 occurs through a noncanonical rhodopsin/Rac2 pathway, which is distinct from the classical phototransduction cascade.