Comparison of manual and artificial intelligence-automated choroidal thickness segmentation of optical coherence tomography imaging in myopic adults.

BACKGROUND: Myopia affects 1.4 billion individuals worldwide. Notably, there is increasing evidence that choroidal thickness plays an important role in myopia and risk of developing myopia-related conditions. With the advancements in artificial intelligence (AI), choroidal thickness segmentation can now be automated, offering inherent advantages such as better repeatability, reduced grader variability, and less reliance for manpower. Hence, we aimed to evaluate the agreement between AI-automated and manual segmented measurements of subfoveal choroidal thickness (SFCT) using two swept-source optical coherence tomography (OCT) systems. METHODS: Subjects aged ≥ 16 years, with myopia of ≥ 0.50 diopters in both eyes, were recruited from the Prospective Myopia Cohort Study in Singapore (PROMYSE). OCT scans were acquired using Triton DRI-OCT and PLEX Elite 9000. OCT images were segmented both automatically with an established SA-Net architecture and manually using a standard technique with adjudication by two independent graders. SFCT was subsequently determined based on the segmentation. The Bland-Altman plot and intraclass correlation coefficient (ICC) were used to evaluate the agreement. RESULTS: A total of 229 subjects (456 eyes) with mean [± standard deviation (SD)] age of 34.1 (10.4) years were included. The overall SFCT (mean ± SD) based on manual segmentation was 216.9 ± 82.7 µm with Triton DRI-OCT and 239.3 ± 84.3 µm with PLEX Elite 9000. ICC values demonstrated excellent agreement between AI-automated and manual segmented SFCT measurements (PLEX Elite 9000: ICC = 0.937, 95% CI: 0.922 to 0.949, P < 0.001; Triton DRI-OCT: ICC = 0.887, 95% CI: 0.608 to 0.950, P < 0.001). For PLEX Elite 9000, manual segmented measurements were generally thicker when compared to AI-automated segmented measurements, with a fixed bias of 6.3 µm (95% CI: 3.8 to 8.9, P < 0.001) and proportional bias of 0.120 (P < 0.001). On the other hand, manual segmented measurements were comparatively thinner than AI-automated segmented measurements for Triton DRI-OCT, with a fixed bias of - 26.7 µm (95% CI: - 29.7 to - 23.7, P < 0.001) and proportional bias of - 0.090 (P < 0.001). CONCLUSION: We observed an excellent agreement in choroidal segmentation measurements when comparing manual with AI-automated techniques, using images from two SS-OCT systems. Given its edge over manual segmentation, automated segmentation may potentially emerge as the primary method of choroidal thickness measurement in the future.

Environmental complexity and feeding enrichment can mitigate effects of space constraints in captive callitrichids.

Non-human primates housed in zoos and laboratories often exhibit reduced activity and this poses welfare concerns. We examined the effects of enclosure types of differing size and environmental complexity on the activities of two species of callitrichids. We found that cotton-top tamarins housed in an enclosure of larger size and more environmental complexity showed higher activity levels, which was mainly contributed by more feeding/foraging activity. By contrast, Goeldi's monkeys housed in an enclosure of larger size and more environmental complexity showed lower activity levels, which was mainly contributed by less locomotory activity. In both species, off-exhibit groups housed in smaller enclosures did not show significantly less locomotory activity which would have been expected, as larger availability spaces should allow more opportunities for locomotion. Furthermore, the feeding enrichment had significant effects on increased feeding/foraging activity for both cotton-top tamarins and Goeldi's monkeys, irrespective of enclosure type. These results suggested that environmental complexity (or application of feeding enrichment) that provided more opportunities for natural foraging could have a larger effect on overall activity levels compared with larger enclosure sizes that should provide more locomotion opportunities. More importantly, it showed that even when enclosure space and complexity were limited, increased opportunities for foraging through the application of enrichment could increase species-typical behaviours. Such inexpensive, easy to implement enrichment methods should be applied to provide more complex environments for captive non-human primates, particularly in situations where there are logistical and/or cost constraints to the modification of physical exhibits.

Up-regulation of microRNA-190b plays a role for decreased IGF-1 that induces insulin resistance in human hepatocellular carcinoma.

BACKGROUND & AIMS: Insulin-like growth factor, (IGF)-1, is produced mainly by the liver and plays important roles in promoting growth and regulating metabolism. Previous study reported that development of hepatocellular carcinoma (HCC) was accompanied by a significant reduction in serum IGF-1 levels. Here, we hypothesized that dysregulation of microRNAs (miRNA) in HCC can modulate IGF-1 expression post-transcriptionally. METHODS: The miRNAs expression profiles in a dataset of 29 HCC patients were examined using illumina BeadArray. Specific miRNA (miR)-190b, which was significantly up-regulated in HCC tumor tissues when compared with paired non-tumor tissues, was among those predicted to interact with 3'-untranslated region (UTR) of IGF-1. In order to explore the regulatory effects of miR-190b on IGF-1 expression, luciferase reporter assay, quantitative real-time PCR, western blotting and immunofluorecence analysis were performed in HCC cells. RESULTS: Overexpression of miR-190b in Huh7 cells attenuated the expression of IGF-1, whereas inhibition of miR-190b resulted in up-regulation of IGF-1. Restoration of IGF-1 expression reversed miR-190b-mediated impaired insulin signaling in Huh7 cells, supporting that IGF-1 was a direct and functional target of miR-190b. Additionally, low serum IGF-1 level was associated with insulin resistance and poor overall survival in HCC patients. CONCLUSIONS: Increased expression of miR-190 may cause decreased IGF-1 in HCC development. Insulin resistance appears to be a part of the physiopathologic significance of decreased IGF-1 levels in HCC progression. This study provides a novel miRNA-mediated regulatory mechanism for controlling IGF-1 expression in HCC and elucidates the biological relevance of this interaction in HCC.

Downregulation of alpha-fetoprotein expression by LHX4: a critical role in hepatocarcinogenesis.

LHX4 is a member of the LIM-homeobox family and plays a critical role in pituitary development and differentiation. Several lines of evidences have reported their aberrant expression in cancers. However, the exact roles of LHX4 in carcinogenesis remain unclear. In this study, LHX4 expression was analyzed in tumor and paired non-tumor tissues obtained from patients with hepatocellular carcinoma (HCC) using western blotting and immunohistochemistry. LHX4 was found to be downregulated in tumor tissues and negatively correlated with differentiation grade and alpha-fetoprotein (AFP) levels in 66 HCC patients. To clarify the biological functions of LHX4, transient or stable transfectants overexpressing LHX4 were generated in human hepatoma cells (Huh7 and HepG2). LHX4 overexpression in Huh7 and HepG2 cells induced a more differentiated phenotype by reducing AFP expression. Using in silico analysis, the evolutionary conserved region within the AFP promoter containing LHX4-binding site was identified, implying that AFP is a putative target for LHX4. Moreover, ectopic LHX4 overexpression attenuated Huh7 and HepG2 proliferation. Importantly, the growth-inhibitory effect of LHX4 was reversed by replenishing AFP to the LHX4-overexpressing cells, providing a functional relevance between LHX4 and AFP. Finally, we analyzed expressions of LHX4 and AFP during normal liver development. Hepatic LHX4 expression increased in adult liver in a manner that parallel AFP repression. In conclusion, these data indicate that LHX4 may act as a potential tumor suppressor in hepatocarcinogenesis, suggesting that targeting LHX4 to downregulate AFP might have therapeutic implications.

Adult invasive pneumococcal disease pre- and peri-pneumococcal conjugate vaccine introduction in a tertiary hospital in Singapore.

Streptococcus pneumoniae isolates causing invasive disease at a large tertiary institute in Singapore from 2000 to 2007 were serotyped, with 84 (43.8 %) and 159 (82.8 %) isolates belonging to serotypes covered by the pneumococcal heptavalent conjugate and polysaccharide vaccines, respectively. All non-meningitis isolates were susceptible to penicillin, and the attributable mortality was 21.4 %. Patients who fulfilled the US Advisory Committee on Immunization Practices criteria for vaccination with the pneumococcal polysaccharide vaccine comprised 74.0 % of the study cohort and had a significantly higher mortality risk.

Clonal amniotic fluid-derived stem cells express characteristics of both mesenchymal and neural stem cells.

Recent evidence has shown that amniotic fluid may be a novel source of fetal stem cells for therapeutic transplantation. We previously developed a two-stage culture protocol to isolate a population of amniotic fluid-derived mesenchymal stem cells (AFMSCs) from second-trimester amniocentesis. AFMSCs maintain the capacity to differentiate into multiple mesenchymal lineages and neuron-like cells. It is unclear whether amniotic fluid contains heterogeneous populations of stem cells or a subpopulation of primitive stem cells that are similar to marrow stromal cells showing the behavior of neural progenitors. In this study, we showed a subpopulation of amniotic fluid-derived stem cells (AF-SCs) at the single-cell level by limiting dilution. We found that NANOG- and POU5F1 (also known as OCT4)-expressing cells still existed in the expanded single cell-derived AF-SCs. Aside from the common mesenchymal characteristics, these clonal AF-SCs also exhibit multiple phenotypes of neural-derived cells such as NES, TUBB3, NEFH, NEUNA60, GALC, and GFAP expressions both before and after neural induction. Most importantly, HPLC analysis showed the evidence of dopamine release in the extract of dopaminergic-induced clonal AF-SCs. The results of this study suggest that besides being an easily accessible and expandable source of fetal stem cells, amniotic fluid will provide a promising source of neural progenitor cells that may be used in future cellular therapies for neurodegenerative diseases and nervous system injuries.

Pregnancy outcomes in unselected singleton pregnant women with an increased risk of first-trimester Down's syndrome.

BACKGROUND: The purpose of this study was to assess outcomes in pregnancies with a positive screen of first-trimester combined test (nuchal translucency, pregnancy-associated plasma protein-A and free beta-human chorionic gonadotropin). METHODS: Using a cut-off level of 1 in 270, 216 (7.1%) women had a positive screen. Among them, 187 delivered their babies in our hospital and the adverse outcomes, such as spontaneous abortion, intrauterine fetal demize, preterm prelabor rupture of the membranes, preterm labor, intrauterine growth restriction, gestational hypertensive disorders, placenta previa, chromosomal abnormalities and fetal structural anomalies, were identified and compared with the 2097 women who screened negative for Down's syndrome. RESULTS: Pregnancies with a positive screen had a significantly higher risk of adverse outcomes than those with negative screens (30.5% versus 15.3%; odds ratio 2.4; p < 0.001), especially for those complicated by spontaneous abortion (odds ratio 11.4; p < 0.05) and placenta previa (odds ratio 4.3; p < 0.05). CONCLUSIONS: Besides fetal chromosomal abnormalities and structural abnormalities, pregnancies with a positive screen for Down's syndrome in the first-trimester had a significantly higher incidence of subsequent adverse obstetric outcomes.

Isolation of human multipotent mesenchymal stem cells from second-trimester amniotic fluid using a novel two-stage culture protocol.

BACKGROUND: The aim of this study was to isolate mesenchymal stem cells (MSCs) from amniotic fluid obtained by second-trimester amniocentesis. METHODS: A novel two-stage culture protocol for culturing MSCs was developed. Flow cytometry, RT-PCR and immunocytochemistry were used to analyse the phenotypic characteristics of the cultured MSCs. Von Kossa, Oil Red O and TuJ-1 stainings were used to assess the differentiation potentials of MSCs. RESULTS: Amniotic fluid-derived MSCs (AFMSCs) were successfully isolated, cultured and enriched without interfering with the routine process of fetal karyotyping. Flow cytometry analyses showed that they were positive for SH2, SH3, SH4, CD29, CD44 and HLA-ABC (MHC class I), low positive for CD90 and CD105, but negative for CD10, CD11b, CD14, CD34, CD117, HLA-DR, DP, DQ (MHC class II) and EMA. Importantly, a subpopulation of Oct-4-positive cells was detectable in our cultured AFMSCs. Under specific culture conditions, AFMSCs could be induced to differentiate into adipocytes, osteocytes and neuronal cells. CONCLUSIONS: We demonstrate that human multipotent MSCs are present in second-trimester amniotic fluid. Considering the great potential of cellular therapy using fetal stem cells and the feasibility of intrauterine fetal tissue engineering, amniotic fluid may provide an excellent alternative source for investigation of human MSCs.

Effects of malonate C60 derivatives on activated microglia.

Activated microglia in acute and chronic neurodegenerative disease of the central nervous system (CNS) can produce large amounts of free radicals, such as reactive oxygen species (ROS), which subsequently contribute to neuropathogenesis. Thus, it is believed that the induction of microglial deactivation can reduce neuronal injury. Buckminsterfullerene (C60) derivatives that possess free radical scavenging properties have been demonstrated to prevent neuronal cell death caused by excitotoxic insult. In this study, we investigated the biological role of two malonic acid C60 derivatives referred as trans-2 and trans-3 on microglia in the presence of the endotoxin lipopolysaccharide (LPS). Treatment of LPS-activated microglia with trans-2 and trans-3 induced a significant degree of transformation of amoeboid microglia to the ramified phenotype. To understand the mechanism underlying this C60 mediated microglial morphological transformation, we examined the production of proinflammatory cytokines, interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha), as well as the final NO products (nitrate and nitrite) in the microglial culture supernatant. Although inducible nitric oxide (iNOS) mRNA and protein expression in LPS-activated microglia were slightly decreased by trans-2 and trans-3, levels of nitrate and nitrite were unaffected. Paradoxically, trans-2 and trans-3 were found to increase the release of IL-1beta in the activated microglial culture. However, trans-2 and trans-3 improved the activity of the antioxidant enzyme, superoxide dismutase (SOD) in LPS-treated microglia. Therefore, our results suggest that the C60 derivatives might increase microglial SOD enzymatic activity which causes microglial morphological transformation from the activated amoeboid phenotype to the resting ramified form.