Ambient Light Regulates Retinal Dopamine Signaling and Myopia Susceptibility

PurposeExposure to high-intensity or outdoor lighting has been shown to decrease the severity of myopia in both human epidemiological studies and animal models. Currently, it is not fully understood how light interacts with visual signaling to impact myopia. Previous work performed in the mouse retina has demonstrated that functional rod photoreceptors are needed to develop experimentally-induced myopia, alluding to an essential role for rod signaling in refractive development.MethodsTo determine whether dim rod-dominated illuminance levels influence myopia susceptibility, we housed male C57BL/6J mice under 12:12 light/dark cycles with scotopic (1.6 × 10⁻³ candela/m²), mesopic (1.6 × 10¹ cd/m²), or photopic (4.7 × 10³ cd/m²) lighting from post-natal day 23 (P23) to P38. Half the mice received monocular exposure to −10 diopter (D) lens defocus from P28–38. Molecular assays to measure expression and content of DA-related genes and protein were conducted to determine how illuminance and lens defocus alter dopamine (DA) synthesis, storage, uptake, and degradation and affect myopia susceptibility in mice.ResultsWe found that mice exposed to either scotopic or photopic lighting developed significantly less severe myopic refractive shifts (lens treated eye minus contralateral eye; –1.62 ± 0.37D and −1.74 ± 0.44D, respectively) than mice exposed to mesopic lighting (–3.61 ± 0.50D; P < 0.005). The 3,4-dihydroxyphenylacetic acid /DA ratio, indicating DA activity, was highest under photopic light regardless of lens defocus treatment (controls: 0.09 ± 0.011 pg/mg, lens defocus: 0.08 ± 0.008 pg/mg).ConclusionsLens defocus interacted with ambient conditions to differentially alter myopia susceptibility and DA-related genes and proteins. Collectively, these results show that scotopic and photopic lighting protect against lens-induced myopia, potentially indicating that a broad range of light levels are important in refractive development.     

What contributes to self‐rated oral health among community‐dwelling older adults? Findings from the ElderSmile program

Objectives: As part of ongoing efforts by the Columbia University College of Dental Medicine to devise community‐based models of health promotion and care for local residents, we sought to answer the following query: “What contributes to self‐rated oral health among community‐dwelling older adults?” Methods: The present study is cross sectional in design and centrally concerned with baseline data collected during community‐based screenings of adults aged 50 years and older who agreed to participate in the ElderSmile program in northern Manhattan, New York City. The primary outcome measure of interest is self‐rated oral health, which was assessed as follows: “Overall, how would you rate the health of your teeth and gums – excellent, good, fair, or poor?” Results: More than a quarter (28.5 percent) of ElderSmile participants aged 50 years and older reported that their oral health was poor. After adjustment for age (in years), place of birth, educational level, and dental insurance status in a logistic regression model, recent visits to the dentist (within the past year versus more than a year ago) contributed to better self‐rated oral health and non‐Hispanic Black race/ethnicity, dentate (versus edentulous) status, tooth decay as measured by decayed missing filled teeth, and severe periodontal inflammation contributed to worse self‐rated oral health in this population. Conclusions: Recent dental care contributed to better self‐rated oral health among community‐dwelling older adults living in northern Manhattan. Significant gradients were evident in the caries experience and periodontal inflammation of dentate adults by self‐rated oral health, suggesting that untreated oral disease contributes to poor self‐rated oral health.     

CT‐guided aspiration cytology of advanced silicosis and confirmation of the deposited zeolite nano particles through X ray diffraction: A novel approach

Silicosis is a common occupational lung disease, resulting in fibrotic nodular lesions in the upper lobes of the lung parenchyma. Most of the pneumoconioses are diagnosed on the basis of relevant history and clinico‐radiological correlation. Image‐guided aspiration cytology appears to be poorly yielding and is not usually considered as a diagnostic modality. However, silicosis may sometimes offer a diagnostic challenge because of its radiological resemblance and clinical overlap with pulmonary tuberculosis and neoplastic lesions. We present a unique situation where image‐guided fine needle aspiration cytology (FNAC) has been advised on the basis of nodular upper lobe opacities. The cytology smears revealed hypocellular granular material, while phase contrast and polarized light microscopy highlighted crystalline particles. History of silica dust exposure long back was available after the cytological evaluation, suggesting the diagnosis of pulmonary silicosis. X ray diffraction (XRD) crystallography was also possible on cytology smears, confirming zeolite nano particles of size as small as 40 ? 50 nm as the concerned agent for the first time. Cytological evaluation by phase contrast and polarized light microscopy may be useful for the confirmation of silicosis, supplemented by clinical history and radiological evaluation. XRD on smears may help in determination of chemical nature and particle size. Diagn. Cytopathol. 2016;44:246–249. © 2015 Wiley Periodicals, Inc.     

Evaluating computer-aided detection algorithms

Computer-aided detection (CAD) has been attracting extensive research interest during the last two decades. It is recognized that the full potential of CAD can only be realized by improving the performance and robustness of CAD algorithms and this requires good evaluation methodology that would permit CAD designers to optimize their algorithms. Free-response receiver operating characteristic (FROC) curves are widely used to assess CAD performance, however, evaluation rarely proceeds beyond determination of lesion localization fraction (sensitivity) at an arbitrarily selected value of nonlesion localizations (false marks) per image. This work describes a FROC curve fitting procedure that uses a recent model of visual search that serves as a framework for the free-response task. A maximum likelihood procedure for estimating the parameters of the model from free-response data and fitting CAD generated FROC curves was implemented. Procedures were implemented to estimate two figures of merit and associated statistics such as 95% confidence intervals and goodness of fit. One of the figures of merit does not require the arbitrary specification of an operating point at which to evaluate CAD performance. For comparison a related method termed initial detection and candidate analysis was also implemented that is applicable when all suspicious regions are reported. The two methods were tested on seven mammography CAD data sets and both yielded good to excellent fits. The search model approach has the advantage that it can potentially be applied to radiologist generated free-response data where not all suspicious regions are reported, only the ones that are deemed sufficiently suspicious to warrant clinical follow-up. This work represents the first practical application of the search model to an important evaluation problem in diagnostic radiology. Software based on this work is expected to benefit CAD developers working in diverse areas of medical imaging.     

Prevalence of vitamin B12 deficiency in healthy Indian school‐going adolescents from rural and urban localities and its relationship with various anthropometric indices: a cross‐sectional study

Background

Micronutrient deficiency is a global health burden, especially among developing countries. The present cross‐sectional study aimed to determine the prevalence of vitamin B₁₂ deficiency in healthy Indian school‐going adolescents, based on area of residence, sex and body mass index (BMI) . Furthermore, the relationship of serum B₁₂ concentration with dietary vitamin B₁₂ intake and anthropometric indices was assessed among adolescents from rural and urban India.

Methods

A total of 2403 school‐going adolescents (11–17 years) from National Capital Region and rural areas of Haryana, India were selected. Serum B₁₂ concentrations were estimated using an electrochemiluminescence immunoassay. Dietary assessments were conducted on 65% of total participants (n  = 1556) by two 24‐h diet recalls.

Results

The prevalence of vitamin B₁₂ deficiency in the total study population was 32.4% (rural: 43.9% versus urban: 30.1%, P  < 0.001; male: 34.4% versus female: 31.0%, P  < 0.05; normal weight: 28.1%, versus overweight: 39.8%, versus obese: 51.2%, P  < 0.001). More than half (51.2%) of obese adolescents were vitamin B₁₂ deficient. On multiple linear regression analysis, serum B₁₂ in rural adolescents was associated with age (β = ?0.12, P  < 0.05). Among urban adolescents, serum B₁₂ was associated with BMI (β = ?0.08, P  < 0.05) and adjusted dietary vitamin B₁₂ intake (β = 0.14, P  < 0.001). Serum vitamin B₁₂ levels were found to be lower in rural females (β = ?0.12, P  = 0.030) and urban males (β: 0.11, P  < 0.001) compared to their respective contemporaries.

Conclusions

Vitamin B₁₂ deficiency was higher among rural school‐going adolescents. Boys had a higher B₁₂ deficiency than girls. Inverse associations of serum B₁₂ with adiposity indices were observed. Serum B₁₂ levels were positively associated with dietary vitamin B₁₂ intake.

     

Finger pulp reconstruction with thenar flap: Aesthetic and functional outcome

Purpose: Fingertip injuries are common in industrial production activities as well as in domestic work. Loss of pulp hampers daily life activities. Functional and aesthetic aspects are important in fingertip reconstruction. The bone is usually exposed along with soft tissue loss. Therefore to reconstruct the pulp flap with adequate bulk is required. Methods: We reported a case series of 12 patients with the injury over the volar aspect of distal phalanx of the index or middle finger. In all cases, laterally based thenar flap was chosen. The flap donor site was closed primarily in most of cases, while 4 patients required skin graft. The flap was detached between 2-3 weeks. Functional assessment was done using static and dynamic 2-point discrimination and range of motion at each joint. The aesthetic outcome was assessed through questionnaire. The results were analyzed using the unpaired t-test (SPSS version 21). Results: Partial necrosis occurred in 2 cases while rest of flaps survived successfully. Static 2-point discrimination ranged from 6e10 mm, mean 8.6 mm; and dynamic 2-point discrimination ranged from 8-10 mm, mean 8.9 mm. The mean satisfaction score was (4.0 ± 0.55). Conclusion: Thenar flap is a good choice for reconstruction of the finger pulp as it provides the bulk with good functional and aesthetic outcome.     

Nocturnal home hemodialysis in children: Advantages,implementation, and barriers

Chronic kidney disease and end-stage renal disease (ESRD) in children are major health concerns worldwide with increasing incidence and prevalence. Renal replacement therapies and kidney transplants have remarkably improved the management of patients with ESRD in both adult and pediatric populations. Kidney transplant has the best patient outcomes, but many a time it has a considerable waiting period. In the meantime, the majority of patients with pediatric ESRD are dependent on dialysis. The conventionally utilized hemodialysis regimen is the three times weekly, in-center hemodialysis. Many studies have demonstrated the unfavorable long-term morbidity associated with the conventional regimen. Intensified dialysis programs, which include extended nocturnal hemodialysis or short daily hemodialysis, are being increasingly advocated over the past two decades. In addition to having much better clinical outcomes as compared with the conventional regimen, the flexibility to provide dialysis at home serves as a great incentive. PubMed/Medline, Embase and Cochrane databases for literature on nocturnal home hemodialysis in children with ESRD were extensively searched. Contrary to the noticeable literature available on adult home hemodialysis, a small number of studies exist in the pediatric population. In this review, the benefits, implementation and associated barriers of nocturnal home hemodialysis in children were addressed.     

Optical mechanisms regulating emmetropisation and refractive errors: evidence from animal models

Our current understanding of emmetropisation and myopia development has evolved from decades of work in various animal models, including chicks, non-human primates, tree shrews, guinea pigs, and mice. Extensive research on optical, biochemical, and environmental mechanisms contributing to refractive error development in animal models has provided insights into eye growth in humans. Importantly, animal models have taught us that eye growth is locally controlled within the eye, and can be influenced by the visual environment. This review will focus on information gained from animal studies regarding the role of optical mechanisms in guiding eye growth, and how these investigations have inspired studies in humans. We will first discuss how researchers came to understand that emmetropisation is guided by visual feedback, and how this can be manipulated by form-deprivation and lens-induced defocus to induce refractive errors in animal models. We will then discuss various aspects of accommodation that have been implicated in refractive error development, including accommodative microfluctuations and accommodative lag. Next, the impact of higher order aberrations and peripheral defocus will be discussed. Lastly, recent evidence suggesting that the spectral and temporal properties of light influence eye growth, and how this might be leveraged to treat myopia in children, will be presented. Taken together, these findings from animal models have significantly advanced our knowledge about the optical mechanisms contributing to eye growth in humans, and will continue to contribute to the development of novel and effective treatment options for slowing myopia progression in children.