Global and regional estimates of prevalence of amblyopia: A systematic review and meta-analysis

Background: Amblyopia is one of the most important causes of vision impairment in the world, especially in children. Although its prevalence varies in different parts of the world, no study has evaluated its prevalence in different geographical regions comprehensively. The aim of the present study was to provide global and regional estimates of the prevalence of amblyopia in different age groups via a systematic search.

Methods: In this study, international databases, including Embase, Scopus, PubMed, Web of Science, and other relevant databases, were searched systematically to find articles on the prevalence of amblyopia in different age groups published in English. The prevalence and 95% CI were calculated using binomial distribution. The Cochran’s Q-test and I² statistic were applied to assess heterogeneity, a random-effects model was used to estimate the pooled prevalence, and a meta-regression method was utilized to investigate the factors affecting heterogeneity between studies.

Results: Of 1252 studies, 73 studies were included in the analysis (sample volume: 530,252). Most of these studies (n = 25) were conducted in the WHO-Western Pacific Regional Office. The pooled prevalence estimate of amblyopia was 1.75% (95% CI: 1.62–1.88), with the highest estimate in European Regional Office (3.67%, 95% CI: 2.89–4.45) and the lowest in African Regional Office (0.51%, 95% CI: 0.24–0.78). The most common cause of amblyopia was anisometropia (61.64%). The I² heterogeneity was 98% (p < 0.001). According to the results of univariate meta-regression, the variables of WHO region (b: 0.566, p < 0.001), sample size (b: ?0.284 × 10^?4, p: 0.025), and criteria for definition of amblyopia (b: ?0.292, p: 0.010) had a significant effect on heterogeneity between studies, while age group, publication date, and cause of amblyopia had no significant effect on heterogeneity.

Conclusion: The prevalence of amblyopia varies in different parts of the world, with the highest prevalence in European countries. Geographical location and criteria for definition of amblyopia are among factors contributing to the difference across the world. The results of this study can help stakeholders to design health programs, especially health interventions and amblyopia screening programs.     

Globin Chain Synthesis is a Useful Complementary Tool in the Differential Diagnosis of Thalassemias

The present study aimed at differentiating rare types of heterozygous β-thalassemia (thal) with normal Hb A₂ values from α-thal in Iranian carriers by globin chain synthesis in addition to other hematological parameters. Our study groups consisted of 51 normal subjects, 24 heterozygous β- thalassemic subjects with high Hb A₂, 62 α-thal-2 subjects, 34 α-thal-1 subjects, six Hb H disease thalassemic subjects, 14 silent β-thal subjects with normal Hb A₂ values, five δβ-thal subjects and two subjects with an association of α- and δβ-thal (total = 198). Analysis of globin chains was performed by high performance liquid chromatography (HPLC). The results showed that the α/β ratio averages were close to the ones in the published literature, but with a greater standard deviation and a wider range.

Globin chain synthesis (GCS) could be valuable in differentiating between microcytosis produced by silent β-thal (heterozygous β-thal with a normal Hb A₂ level) and that caused by α-thal. Since the complex genotype/phenotype relationship can lead to diagnostic difficulties, GCS cannot be used as the only diagnostic tool for thalassemia carrier detection. Therefore, a combination of different tests for each patient is required.     

The relationship of air pollution and surrogate markers of endothelial dysfunction in a population-based sample of children

Background  

This study aimed to assess the relationship of air pollution and plasma surrogate markers of endothelial dysfunction in the pediatric age group.     

Removing peroxide impurities from ether improves the quality of globin chains for biosynthetic studies

The diagnosis of the different forms of thalassemia is one of the important applications of analysis of globin chains. These analyses are done by high performance liquid chromatography (HPLC) using a MONO-S cation exchange column and ether is used for washing the globin powder in the final step. The presence of peroxide impurities in ether could change the structure of the globin chains. In the chromatograms, these modified globins appear as separated peaks next to the unmodified globin peaks. In these cases, the alpha/beta ratio exceed by artifact the correct value. Our study demonstrates that diagnostic centers should ensure that the ether they use is pure.     

Treatment of LS174T colorectal cancer stem-like cells with n-3 PUFAs induces growth suppression through inhibition of survivin expression and induction of caspase-3 activation

Purpose

Colorectal cancer stem cells (CCSCs) are thought to contribute to tumor initiation, progression, metastasis, chemo-resistance and therapy failure. Therefore, assessment of the effectiveness of agents with anti-proliferative activities against CCSCs is warranted. Several studies have shown that different tumorigenic steps, ranging from initiation to metastasis, can be affected by n-3 polyunsaturated fatty acids (PUFAs). Here, we evaluated the effects of the PUFA components docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), alone or in combination, on LS174T cells that serve as a model for colorectal cancer initiating cells with stem cell-like properties.

Methods

LS174T cells were treated with 50, 100 and 150 μM DHA and EPA, or equal mixtures of DHA/EPA (i.e., 25/25, 50/50 and 75/75 μM), after which cell number, viability, growth inhibition, survivin expression, caspase-3 activation and apoptotic rate were evaluated.

Results

We found that treatment of LS174T cells with increasing PUFA concentrations significantly increased growth inhibition in a dose- and time-dependent manner. After a 72 h treatment with 150 μM DHA and EPA, or their combination (75/75 μM), growth rates were inhibited by 80.3?±?5.5 %, 79.3?±?5 % and 71.1?±?1 %, respectively, compared to untreated cells. We also found that treatment for 48 h with 100 μM DHA and EPA, or their combination (50/50 μM), resulted in 2.9-, 3- and 2.6-fold increases in caspase-3 activation, as well as 54, 62.4 and 100 % decreases in survivin mRNA expression levels, respectively, compared to untreated cells. Low survivin mRNA levels combined with high caspase-3 activity levels were found to correlate with a higher growth inhibition in PUFA-treated cells. DHA appears to be a more potent growth inhibitor than EPA and the DHA/EPA combination. An increase in the number of apoptotic cells (early?+?late), ranging from 12.9 to 44.7 %, was observed with increasing DHA doses.

Conclusion

From our data we conclude that PUFAs induce growth inhibition via targeting survivin expression in LS174T cells, which serve as a model for CCSCs.

     

Prediction of the presence of renal artery stenosis by calcium scoring of the abdominal aorta

Objective

To establish a method for estimating the probability of renal artery stenosis (RAS) based on the calcium volume score of the aorta (ACS).

Materials and Methods

In a retrospective observation study, CT angiographies acquired on a 64-slice MDCT scanner were analyzed for 1351 patients (female: 531; male 826; mean age 60.9 ± 17.7 years). A volumetric scoring method was used, detecting plaques with a density of more than 600 HU.

Results

13.8% of the patients showed a stenosis >50%, 4.1% a stenosis >70%. The ACS was 0.61 ± 1.01 ml calcium. The sensitivity for detection of RAS >50% and RAS >80% was 0.9572 and 1.0, respectively. The negative predictive value (NPV) of a lack of calcification for excluding RAS >50% and RAS >80% was 0.9752 and 1, respectively. As ACS increased, the specificity for RAS >50% increased to 0.9390. With an ACS of 0.380 ml, accuracy reached a maximum of 0.6585. ROC analyses yielded an area under the curve of 0.88 (p < 0.0001). Sensitivity, specificity, NPV and PPV are indicated in relation to the degree of RAS, as well as the diagnostic yield of the method, which is valuable in patients older than 50 years.

Conclusion

Due to its extremely high sensitivity and NPV, the ACS is a very useful screening method for RAS. The validity of the method, as well as its diagnostic value is equivalent to that of coronary artery calcium scoring. Lack of calcifications of the aorta renders atherosclerotic RAS highly improbable.     

A novel fibrin-based artificial ovary prototype resembling human ovarian tissue in terms of architecture and rigidity

Purpose

The aim of this study is to optimize fibrin matrix composition in order to mimic human ovarian tissue architecture for human ovarian follicle encapsulation and grafting.

Methods

Ultrastructure of fresh human ovarian cortex in age-related women (n?=?3) and different fibrin formulations (F12.5/T1, F30/T50, F50/T50, F75/T75), rheology of fibrin matrices and histology of isolated and encapsulated human ovarian follicles in these matrices.

Results

Fresh human ovarian cortex showed a highly fibrous and structurally inhomogeneous architecture in three age-related patients, but the mean?±?SD of fiber thickness (61.3 to 72.4 nm) was comparable between patients. When the fiber thickness of four different fibrin formulations was compared with human ovarian cortex, F50/T50 and F75/T75 showed similar fiber diameters to native tissue, while F12.5/T1 was significantly different (p value?<?0.01). In addition, increased concentrations of fibrin exhibited enhanced storage modulus with F50/T50, resembling physiological ovarian rigidity. Excluding F12.5/T1 from further analysis, only three remaining fibrin matrices (F30/T50, F50/T50, F75/T75) were histologically investigated. For this, frozen-thawed fragments of human ovarian tissue collected from 22 patients were used to isolate ovarian follicles and encapsulate them in the three fibrin formulations. All three yielded similar follicle recovery and loss rates soon after encapsulation. Therefore, based on fiber thickness, porosity, and rigidity, we selected F50/T50 as the fibrin formulation that best mimics native tissue.

Conclusions

Of all the different fibrin matrix concentrations tested, F50/T50 emerged as the combination of choice in terms of ultrastructure and rigidity, most closely resembling human ovarian cortex.

     

Comparative analysis of anthropometric indices with serum uric acid in Iranian healthy population

BackgroundThe relationship between elevated serum uric acid (SUA) levels and hypertension, metabolic syndrome and cardiovascular disease has been established. In this study, the relation of SUA levels to anthropometric indices, blood cell count and lipid profile was examined.MethodsAnthropometric parameters including body‐mass index, waist circumference, waist to height ratio, waist to hip ratio, waist to pelvic ratio, neck circumference (NC), body fat mass (BFM), basal metabolic rate (BMR), visceral fat level (VFL) and percent body fat (PBF), along with complete blood cell count, lipid profile and SUA were obtained from 2921 young and middle‐aged Iranian healthy subjects. To assess the normality of data, the Kolmogorov–Smirnov test was used. Mann‐Whitney, Kruskal‐Wallis, Chi‐square and Spearman correlation tests were used for evaluating the association between variables. Simple and multiple regression analyses were also performed.ResultsThe results of data analysis showed all studied factors were correlated with SUA level except VFL, BFM, and platelet‐to‐lymphocyte ratio. The highest correlation was with NC, BMR, hematocrits (HCT) and triglycerides (TG). The backward method revealed that TG, LDL, HDL, neutrophil, lymphocyte, platelet, HCT, BMR and skinfold fat thickness were factors related to SUA.ConclusionsAccording to the finding of this study, SUA level is related to anthropometric indices, lipid profile and neutrophil to lymphocyte ratio in healthy population. SUA measurement might be advisable to identify those at increased risk of health problems whom might benefit from further evaluation.