Pediatric cycloplegic refraction

Background: Cycloplegic refraction is an essential part of the pediatric ophthalmic assessment and is the cornerstone of strabismus evaluation. This narrative review aimed to ascertain the current scope of practice for cycloplegic refraction in the pediatric population. Methods: An extensive literature review was conducted using ScienceDirect, PubMed/MEDLINE, Scopus, and Google Scholar databases using the following search terms: cyclopentolate, tropicamide, pediatric cycloplegia, atropine, homatropine, manual retinoscope, handheld autorefractometer, spherical errors, and no spherical errors of refraction in articles published from January 2000 to December 2022. Relevant retrieved references and practical points concerning pediatric cycloplegic refraction were summarized. Results: Atropine has the most potent cycloplegic effect and is best used in cases of severe accommodative esotropia. Because of the unfavorable side effects and risks associated with atropine, cyclopentolate has been found to provide quite effective cycloplegia, even for moderate to severe hyperopia, and has become the standard agent for traditional pediatric cycloplegic exams. Tropicamide has also been shown to provide adequate cycloplegia while being less toxic and causing fewer side effects. Tropicamide has the fewest side effects and toxicity of all agents, while atropine has the most. Cyclopentolate is an exceptionally safe cycloplegic agent. To detect spherical and non-spherical refractive errors, refraction can be performed using a handheld autorefractometer or a manual retinoscope, as well as under general anesthesia in some cases. The optimal time to wear eyeglasses to maintain binocular vision and avoid amblyopia is also considered. Conclusions: Accommodative power in children is at its maximum, and this interferes with reliable - assessment of refraction. Therefore, the use of cycloplegic refraction is mandatory during childhood to obtain actual refraction, which is considered the cornerstone for eyeglass prescription. Knowledge of the various cycloplegic agents used in childhood refraction is important for ophthalmologists and optometrists to obtain safe and effective cycloplegia. High refractive errors, as well as the presence of anisometropia or squint, necessitate the use of eyeglasses as early as childhood to maintain binocularity and depth perception

The impact of image dynamic range on texture classification of brain white matter

<p>Abstract</p> <p>Background</p> <p>The Greylevel Cooccurrence Matrix method (COM) is one of the most promising methods used in Texture Analysis of Magnetic Resonance Images. This method provides statistical information about the spatial distribution of greylevels in the image which can be used for classification of different tissue regions. Optimizing the size and complexity of the COM has the potential to enhance the reliability of Texture Analysis results. In this paper we investigate the effect of matrix size and calculation approach on the ability of COM to discriminate between peritumoral white matter and other white matter regions.</p> <p>Method</p> <p>MR images were obtained from patients with histologically confirmed brain glioblastoma using MRI at 3-T giving isotropic resolution of 1 mm³. Three Regions of Interest (ROI) were outlined in visually normal white matter on three image slices based on relative distance from the tumor: one peritumoral white matter region and two distant white matter regions on both hemispheres. Volumes of Interest (VOI) were composed from the three slices. Two different calculation approaches for COM were used: i) Classical approach (CCOM) on each individual ROI, and ii) Three Dimensional approach (3DCOM) calculated on VOIs. For, each calculation approach five dynamic ranges (number of greylevels N) were investigated (N = 16, 32, 64, 128, and 256).</p> <p>Results</p> <p>Classification showed that peritumoral white matter always represents a homogenous class, separate from other white matter, regardless of the value of N or the calculation approach used. The best test measures (sensitivity and specificity) for average CCOM were obtained for N = 128. These measures were also optimal for 3DCOM with N = 128, which additionally showed a balanced tradeoff between the measures.</p> <p>Conclusion</p> <p>We conclude that the dynamic range used for COM calculation significantly influences the classification results for identical samples. In order to obtain more reliable classification results with COM, the dynamic range must be optimized to avoid too small or sparse matrices. Larger dynamic ranges for COM calculations do not necessarily give better texture results; they might increase the computation costs and limit the method performance.</p

Safety and efficacy of topical tacrolimus 0.03% in the management of vernal keratoconjunctivitis: a non-randomized controlled clinical trial

Background: Vernal keratoconjunctivitis (VKC) is a bilateral, recurrent, chronic conjunctival inflammatory disease with seasonal exacerbations. This study aimed to assess the efficacy and safety of tacrolimus 0.03% eye ointment in the management of chronic VKC. Methods: This was an open-label, prospective, non-randomized, comparative interventional study that enrolled 50 patients with chronic VKC, who were allocated to one of two groups. The first group was treated with tacrolimus 0.03% eye ointment twice daily for 2 months then once daily for 2 months, followed by once every other day for another 2 months. The control group was treated with standard anti-allergic drugs, topical fluorometholone 0.1% eye drops three times daily for 2 weeks and gradually tapered for another 2 weeks, with topical olopatadine 0.1% administered twice daily during the follow-up period. Disease severity was assessed using a four-point scale for symptoms and signs. Treatment efficacy was assessed by analyzing changes in symptoms and signs, and by clinical photography. Results: Fifty patients with bilateral chronic VKC completed the follow-up. The mean (standard deviation) ages of the tacrolimus and control groups were comparable (16.20 [5.10] years versus 16.48 [4.19] years, P &gt; 0.05). The most commonly reported symptom was itching, and the most common signs were papillary hypertrophy and conjunctival hyperemia. All symptoms and signs were significantly reduced after treatment in both groups. The tacrolimus group showed a more significant improvement at 3 and 6 months in the mean composite symptom score (both P &lt; 0.05) and in the mean composite sign score (both P &lt; 0.05). Regarding complications, one case of increased intraocular pressure occurred in the control group (4%) after 2 weeks of steroid treatment, while there were no complications in the tacrolimus group, except for some reports of stinging sensation, which was well tolerated. Conclusions: Treatment of chronic bilateral VKC with tacrolimus 0.03% eye ointment is effective and safe. It could be considered an alternative treatment to reduce steroid-associated complications in patients with chronic VKC. Future double-blinded clinical trials with a longer follow-up period are necessary to confirm our findings and to determine the long-term safety of topical tacrolimus 0.03% ointment in VKC

BotCap: Machine Learning Approach for Botnet Detection Based on Statistical Features

In this paper, we describe a detailed approach to develop a botnet detection system using machine learning (ML)techniques. Detecting botnet member hosts, or identifying botnet traffic has been the main subject of manyresearch efforts. This research aims to overcome two serious limitations of current botnet detection systems:First, the need for Deep Packet Inspection-DPI and the need to collect traffic from several infected hosts. Toachieve that, we have analyzed several botware samples of known botnets. Based on this analysis, we haveidentified a set of statistical features that may help to distinguish between benign and botnet malicious traffic.Then, we have carried several machine learning experiments in order to test the suitability of ML techniques andalso to pick a minimal subset of the identified features that provide best detection. We have implemented ourapproach in a tool called BotCap whose test results showed its proven ability to detect individually infected hostsin a local network

Clinical and echocardiographic evaluation of patients undergoing total leaflets preservation during mitral valve replacement; Does it make a difference?

Background: The effect of anterior and posterior leaflet preservation on left ventricular function after mitral valve replacement is still the subject of ongoing research. The objective of this study is to analyze the early outcomes of total leaflets preservation compared to posterior and non-leaflet preservation during mitral valve surgery on cardiac function and dimensions measured by echocardiography and on the clinical outcomes.Methods: This prospective cohort study recruited 155 patients who had mitral valve replacement (MVR) from April 2016 to March 2018 at Assiut University Hospital. Patients were divided into three groups according to the technique of leaflets preservation; Group I (no leaflet preservation-N-MVR), Group II (total leaflet preservation- T-MVR) and Group III (posterior leaflet preservation-P-MVR). Patients who underwent redo mitral valve replacement (MVR) or those with endocarditis and had combined coronary artery bypass grafting with the MVR were excluded from the study.Results: There were nine early deaths (6%); eight patients were in Group I (N-MVR). Causes of mortality were massive intracranial hemorrhage (n= 2) and left ventricular failure (n=6). One patient died in Group III (P-MVR) from intracranial hemorrhage (1.3%). Hospital stay was significantly longer in N-MVR group compared to T-MVR and P-MVR (10.6±2.13 days in N-MVR group; p= 0.03 and 0.011 respectively). Postoperative low cardiac output occurred in all patients in N-MVR group. Left ventricular function (ejection fraction= 61.28±6.02%) and dimensions (end-diastolic diameter= 5.18±0.69 mm, end-systolic diameter= 3.58±0.78 mm) improved significantly in total leaflets preservation group.Conclusion: Leaflet preservation during mitral valve replacement was associated with improved clinical and echocardiographic outcomes. Non-leaflets preservation increased the risk of postoperative complications and length of hospital stay. Leaflet preservation is recommended as the standard approach during mitral valve replacement

The effect of microfinance on income inequality: Perspective of developing countries

Aim/purpose – Studying the impact of microfinance on income inequality from a macro- -economic perspective. Design/methodology/approach – Cross-sectional regression analysis is used to measure the effect of microfinance on the Gini index in a sample of 30 developing countries from across Africa, Asia, Latin America, and Europe. A set of control variables are added to the model including: inflation, educational attainment, democracy, population growth, percentage of arable land to strengthen the model’s reliability. Findings – Results indicate that neither a positive nor a negative impact of microfinance on Gini index could be significantly proved for the sample countries. Research implications/limitations – Due to lack of data availability, research is con-ducted on a small sample of 30 countries. Therefore, to obtain more generalisable results, it is recommended for future research to use a larger sample. Originality/value/contribution – Microfinance is becoming a focal issue in alleviating poverty and inequality, and this paper’s main contribution is that it explores this matter from a macro-economic perspective by looking at the holistic impact of microcredit on a sample of developing countries. Hence, the paper provides further investigation and suggestions for a better implementation of microfinance policies

Texture analysis of magnetic resonance images of rat muscles during atrophy and regeneration

OBJECTIVES: The goals of the current study were (i) to introduce texture analysis on magnetic resonance imaging (MRI-TA) as a noninvasive method of muscle investigation that can discriminate three muscle conditions in rats; these are normal, atrophy and regeneration; and (ii) to show consistency between MRI-TA results and histological results of muscle type 2 fibers\u27 cross-sectional area. METHOD: Twenty-three adult female Wistar rats were randomized into (i) control (C), (ii) immobilized (I) and (iii) recovering (R) groups. For the last two groups, the right hind limb calf muscles were immobilized against the abdomen for 14 days; then, the hind limb was remobilized only for the R group for 40 days. At the end of each experimental period, MRI was performed using 7-T magnet Bruker Avance DRX 300 (Bruker, Wissembourg); T1-weighted MRI acquisition parameters were applied to show predominantly muscle fibers. Rats were sacrificed, and the gastrocnemius muscle (GM) was excised immediately after imaging. (A) Histology: GM type 2 fibers (fast twitch) were selectively stained using the adenosine triphosphatase (ATPase) technique. The mean cross-sectional areas were compared between the three groups. (B) Image analysis: regions of interest (ROIs) were selected on GM MR images where statistical methods of texture analysis were applied followed by linear discriminant analysis (LDA) and classification. RESULTS: Histological analysis showed that the fibers\u27 mean cross-sectional areas on GM transversal sections represented a significant statistical difference between I and C rats (ANOVA, P&lt;.001) as well as between R and I rats (ANOVA, P&lt;.01), but not between C and R rats. Similarly, MRI-TA on GM transversal images detected different texture for each group with the highest discrimination values (Fisher F coefficient) between the C and I groups, as well as between I and R groups. The lowest discrimination values were found between C and R groups. LDA showed three texture classes schematically separated. CONCLUSION: Quantitative results of MRI-TA were statistically consistent with histology. MRI-TA can be considered as a potentially interesting, reproducible and nondestructive method for muscle examination during atrophy and regeneration

Acute vascular rejection after kidney transplantation outcome and effect of different therapeutic modalities

Background: Steroid resistant acute vascular rejection (AVR) is a great obstacle in successful renal transplantation (KTx). The aim of this work was to evaluate the outcome of histologically confirmed acute vascular rejection - which occurred in severe aggressive form in 39 patients following kidney transplantation as well as to study the outcome of therapy. These cases were chosen from 1000 renal allograft recipients who underwent kidney transplantation in the period between March, 1976 and April 1997 in Urology-Nephrology Center, Mansoura, Egypt.Methods: Statistical analysis of risk factors leading to AVR was carried out. The outcome of different rescue therapies used for AVR as well as graft survival functions were also analyzed.Results: Survival analysis for grafts with AVR revealed 60%, 53%, 30 %, 0% graft survival at 1, 2, 5, 10 yrs respectively after Tx. A statistically significant difference was found in comparison to patients who only experienced acute cellular rejection (90%, 84%, 71%, 46% graft survival at 1, 2, 5, 10 years post- KTx respectively) or patients who passed without rejection in their post-transplantation follow up (95%, 91.3%, 83.3%, 65.5% graft survival at 1, 2, 5, 10 yrs respectively). No statistically significant difference on the overall graft survival between the different modalities of therapy was noted. Steroid pulses + plasma exchange were given for 14 patients with AVR, whereas ATG, MAB ± plasma exchange were added to steroid resistant cases (25 patients). Logistic regression analysis of these data showed that prior blood transfusion, donor-recipient consanguinity, retransplantation are the most significant variables related to occurrence of AVR after kidney transplantation. At last follow up, 14 patients 35.9%) were living with functioning grafts, 16 patients (41%) were living on dialysis, 5 patients died with functioning grafts (12.8%) and 4 patients (10.25%) died with failed grafts.In conclusion: AVR remains a major obstacle for renal transplantation as it markedly impaired graft survival and responded poorly to therapy. Prior blood transfusion decreased the incidence of AVR whereas retransplantation and unrelated donation account significantly to the occurrence of AVR after renal Tx