Early fate decisions in hematopoietic stem and progenitor cells. Through the lens of genomic and functional assays.

Hematopoietic stem cells (HSCs) are rare cells on top of the differentiation hierarchy of hematopoiesis. HSCs are unique in their combined capacity to differentiate into all mature blood lineages and self-renew to maintain the HSC pool. Based on classical models of hematopoiesis in mouse, the self-renewal potential of HSCs is gradually and step-wise lost during the transition from long term (LT)-HSCs to multipotent progenitors (MPPs) accompanied by upregulated expression of the cell-surface marker FMS-like tyrosine kinase 3 (Flt3). The Flt3+ multipotent progenitors serve as developmental intermediates for hematopoietic lineage priming. Notably, the 25% highest Flt3+ cells, known as lymphoid-primed MPPs (LMPPs), have been defined as restricted, lymphoid primed cells with decreased megakaryocyte and erythroid (MegE) priming. However, recent single cell RNA sequencing (scRNA-seq) studies question the step-wise model of HSC differentiation and instead suggest a continuum model of the early hematopoietic hierarchy, where the first differentiation events occur in a low-primed cloud of HSPCs without sharply defined gene expression programs. In this model, no transition of different lineages from MPPs with intermediate gene expression occur, instead these progenitors are largely comprised of uni-lineage-primed cells. The overall aim of this thesis is to investigate how cellular-fate options emerge in the cloud of hematopoietic stem/progenitor cells (HSPCs), at what stage the multipotency gives way to lineage priming, and how this stage can be detected. For this aim, single-cell (sc) chromatin accessibility (ATAC-seq), scRNA-seq and sc-qPCR analysis were employed extensively to identify the transition of HSCs to lineage restricted multipotent progenitor cells and functionally validated using in vivo and in vitro assay.In paper I, scATAC-seq was used to map the accessibility of 571 transcription factor (TF)-binding motifs as a measure of lineage priming along the Flt3 differentiation axis. The resulting data identified a transition point of highly lineage-primed cells within the continuum of HSPCs where self-renewal and multipotency was lost and lineage commitment initiated. This transition point is characterized by down-regulation of CD9 and up-regulation of Flt3 cell surface expression. Within the Flt3 intermediate population (Flt3int), LSKFlt3intCD9high cells display co-incidental stem and multi-lineage primed chromatin states while the downstream LSKFlt3intCD9low contain an LMPP-like program. Also, this priming seems to initiate in the epigenome without being starkly reflected in the transcriptome. In order to validate the genomic data from the aforementioned analysis, we established in vitro culture systems to functionally examine the differentiation fates of cells at a clonal level (Paper II). The result confirms that LSKFlt3intCD9high cells generated more multilineage progeny compared to clones within the LSKFlt3intCD9low fraction. It has been shown extensive changes in heterogeneity of human hematopoietic cells with age. For example increase HSCs frequency and myeloid output while lymphoid output is decreased. However human immunophenotypic changes associated with aging have received little attention. To this end we in paper III examined CD9 cell surface expression in correlation with molecular programs and functional features of human HSPCs throughout life and in leukemia. Interestingly, only a small fraction of HSPCs expressed CD9 in neonatal hematopoiesis and in young adult bone marrow while CD9 expression substantially increased during situations of myeloid and megakaryocytic biased hematopoiesis, such as during ageing or in chronic myeloid leukemia (CML). Thus, CD9 represents an HSC marker for myeloid-biased hematopoiesis

Variable Expressivity of Wolfram Syndrome in a Family with Multiple Affected Subjects

Purpose: To study the genetic basis and clinical manifestations of Wolfram syndrome in a multi-affected family. Methods: Complete clinical examinations including urological, ophthalmic, neurological, and endocrinologic assessment were performed for three affected family members. Genomic DNA was extracted from peripheral blood leukocytes with salting out method and all WFS1 exons and their flanking regions were sequenced. Candidate variation was screened for segregation in the pedigree by Sanger sequencing. Results: A known pathogenic missense mutation in WFS1 gene (c.1885C>T which leads to p.Arg629Trp in the encoded protein) was identified in all affected individuals. Both clinical and genetic investigations confirmed Wolfram syndrome diagnosis with variable phenotypic features. Conclusion: Identical mutations in the Wolfram syndrome causative gene can lead to variable manifestations of the syndrome even in the same family. Although the medical findings and clinical examination are imperative for the diagnosis of Wolfram syndrome, genetic testing is useful to confirm the diagnosis, especially in cases with possible reduced penetrance of the characteristic signs

Correlation of Sacral Ratio and Reflux-Related Renal Injury in Children with Vesicoureteral reflux with and without Nephropathy

Introduction: Vesicoureteral reflux refers to the retrograde flow of the urine from the bladder to the ureter and kidney. The ureteral attachment to the bladder is normally oblique, between the bladder mucosa and detrusor muscle, creating a flap-value mechanism that prevents reflux. Reflux occurs when the submucosal tunnel between the mucosa and detrusor muscle is short or absent. The inflammatory reaction caused by pyelonephritis can result in scarring, which is also termed reflux nephropathy. Since sacral bone anomalies have a direct influence on the final function of the urinary and bowel systems, this study was performed to investigate the relationship between sacral ratio and reflux nephropathy.Materials and Methods: In this case–control study, the case -control group included 200 children under 9 years old who were referred to Amir-Kabir Hospital clinics with urinary tract infection and according to the VCUG and DMSA results, children with various grades of VUR entered the study. The sacral ratio was measured in the two groups and compared by a radiologist. The data were analyzed using Chi-2 and Mann Whitney Tests and software SPSS 16.Results: The case group included 48 males and 52 females with a mean age of 3.7 years old who had reflux nephropathy, and the control group included 47 males and 53 females with a mean age of 4.1 years who did not have reflux nephropathy. Sacral ratio abnormality was detected in 64% and 23.7% of the cases and controls respectively, which showed a significant difference (p-value=0.003).Conclusions: Sacral ratio abnormality was more common in children with vesicoureteral reflux and reflux nephropathy than children with VUR without reflux nephropathy.Keywords: Vesico-Ureteral  Reflux;  Sacral agenesis; Child;  Diagnostic imaging

First trimester determination of fetal gender by ultrasonographic measurement of anogenital distance: A cross-sectional study

Background: In some patients with a family history of the gender-linked disease, determination of the fetal gender in the first trimester of pregnancy is of importance. In X-linked recessive inherited diseases, only the male embryos are involved, while in some conditions, such as congenital adrenal hyperplasia, female embryos are affected; hence early determination of fetal gender is important. Objective: The aim of the current study was to predict the gender of the fetus based on the accurate measurement of the fetal anogenital distance (AGD) by ultrasound in the first trimester. Materials and Methods: To determine the AGD and crown-rump length in this cross-sectional study, 316 women with singleton pregnancies were exposed to ultrasonography. The results were then compared with definitive gender of the embryos after birth. Results: The best cut-off for 11 wk to 11 wk, 6 days of pregnancy was 4.5 mm, for 12 wk to 12 wk, 6 days was 4.9 mm, and for 13 wk to 13 wk, 6 days was 4.8 mm. Conclusion: AGD is helpful as an ultrasonographic marker that can determine fetal gender in the first trimester, especially after 12 wks. Key words: Sonography, Gender, Female, Male, Pregnancy, First trimester

Effect of Metal Artifacts on Detection of Vertical Root Fractures Using Two Cone Beam Computed Tomography Systems

Introduction: Vertical root fracture (VRF) is common in endodontically treated teeth. Conventional and digital radiographies have limitations for detection of VRFs. Cone-beam computed tomography (CBCT) offers greater detection accuracy of VRFs in comparison with conventional radiography. This study compared the effects of metal artifacts on detection of VRFs by using two CBCT systems. Methods and Materials: Eighty extracted premolars were selected and sectioned at the level of the cemento-enamel junction (CEJ). After preparation, root canals were filled with gutta-percha. Subsequently, two thirds of the root fillings were removed for post space preparation and a custom-made post was cemented into each canal. The teeth were randomly divided into two groups (n=40). In the test group, root fracture was created with Instron universal testing machine. The control teeth remained intact. CBCT scans of all teeth were obtained with either New Tom VGI or Soredex Scanora 3D. Three observers analyzed the images for detection of VRF. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for VRF detection and percentage of probable cases were calculated for each imaging system and compared using non-parametric tests considering the non-normal distribution of data. The inter-observer reproducibility was calculated using the weighted kappa coefficient. Results: There were no statistically significant differences in sensitivity, specificity, PPV and NPV between the two CBCT systems. Conclusion: The effect of metal artifacts on VRF detection was not significantly different between the two CBCT systems.Keywords: Cast Post; CBCT; Cone-Beam Computed Tomography; Vertical Root Fractur

Prenatal Risk Factors for Infantile Reflux Nephropathy

Introduction: Vesicoureteral reflux (VUR) refers to the retrograde flow of the urine from the bladder to the ureter and kidney. In children with a febrile urinary tract infection (UTI), those with reflux are 3 times more likely to develop renal injury compared to those without reflux. Reflux nephropathy was once accounted for as much as 15-20% of end-stage renal disease in children and young adults. With greater attention to the management of UTIs and a better understanding of reflux, end-stage renal disease secondary to reflux nephropathy is uncommon. Reflux nephropathy remains one of the most common causes of hypertension in children. Reflux in the absence of infection or elevated bladder pressure does not cause renal injury. We sought to determine the association of infantile reflux nephropathy (IRN) with prenatal risk factors. Materials and Methods: In this study, 96 infants with reflux-related renal injury and 96 infants with VUR without reflux nephropathy were evaluated. Maternal information was assessed. Data was analyzed using SPSS version 18.Results: The results of this study showed that age more than 35 years, pre-gestational hypertension, preeclampsia and eclampsia, preterm delivery, very low birth weight (VLBW), pre gestational diabetes mellitus, and maternal BMI<18.5kg/m2 (underweight) were prenatal risk factors for infantile reflux nephropathy.Conclusions: The data suggests that prenatal factors may affect the risk of IRN. Adequate prenatal care and good maternal support can be effective in the prevention of reflux-related renal injury. Keywords: Vesico-Ureteral Reflux; Risk Factors; Prenatal; Infant

Cone-beam Computed Tomography Study of the Root and Canal Morphology of Maxillary and Mandibular Canines Regarding Gender and Age in an Iranian Population

Objectives Canine teeth are supposed to have one single root canal, but they may have some anatomical variations. This study aimed to investigate the morphology of root canals of maxillary and mandibular canines regarding gender and age in an Iranian population using cone-beam computed tomography (CBCT). Methods Using CBCT images, 126 maxillary and 125 mandibular canines were evaluated. Root anatomy was assessed regarding root length, root curvature, number of roots and canals, and pattern of root canal system. The data were analyzed by the Kruskal Wallis and Mann-Whitney tests and multinomial regression model.  Results The mean root length of male patients was significantly higher than females (p=0.0001). The most frequent root curvatures were towards the distal and buccal. Mandibular teeth (p=0.020) and females (p=0.012) had higher frequency of root curvature. All maxillary canines had one root; whereas 1.6% of mandibular canines had two roots. High prevalence of two canals was reported (34.9% of maxillary and 18.4% of mandibular canines). The most prevalent canal patterns included type I (65.1%) followed by type III (34.9%) in maxillary canines and types I (81.6%), III (16.8%) and V (1.6%) in mandibular canines. Higher frequency of type III canal configuration was reported in maxillary teeth (p=0.001) and male patients (p=0.008). No significant difference was found in any parameter between different age groups (p>0.05). Conclusion A high percentage of type III canal configuration in canine teeth especially maxillary canines and male patients was reported. Mandibular teeth and females had higher frequency of root curvature

Enhancing the Remediation Capacity of Mercury Ions from Fluorescent Lamp Using Roasted Date Pits and Its Modified Forms

One of the most toxic heavy metals in the environment is mercury (Hg). However, it still has major uses in various industrial and agricultural applications; leading to localized mercury pollution. There has been an increase in the number of used fluorescent lamps compared to incandescent bulbs. Mercury is being used in fluorescent lamps in the elemental form where it can be vaporized under high pressure. The elemental form of mercury is also lipid soluble and can pass through both brain barrier and the placenta which can cause neurological disorder. Due to its harmful effect, the spent fluorescent lamps (SFLs) are being classified as hazardous wastes where mercury may leach and contaminate soil and groundwater. For these reasons the fluorescent lamps should be treated to reduce potential Hg toxicity or to use other components after recycling; e.g. glass and aluminum cap. Various extraction methods are available in the literature. However, in this project, two methods of extracting mercury from SFL were performed to assess their efficiency: acid extraction and microwave digestion. It was shown that the acid extraction only, using different acids ratios, were not able to remove all mercury from phosphor powder. However, the combination of acid extraction with a microwave digestion enhanced the efficiency of mercury extraction by more than 90%. Physicochemical treatment such as adsorption is also viewed as one of the easiest, safest, adaptable, and cost-effective physical chemical treatment methodologies in remediating toxic metals from aqueous medium. Though, the growing costs and environmental concerns linked with the commercial adsorbents has steered a new research orientation, which intended at developing low cost adsorbents that are produced from waste materials which are natural and renewable resources. Date pits as agricultural waste materials have been effectively employed as an adsorbent for remediating various heavy metals from aqueous media and normally with the benefits of being low cost, naturally available, and environmentally friendly. Chemical modifications processes were also be employed to improve their remediation capacity and selectivity. The current study, therefore, investigated the effect of different modification treatments on the roasted date pits (RODPs) surface chemistry and therefore; enhancing the mercury remediation capacity. The RODPs was grafted with organosilane to remediate Hg2? from the extracted fluorescent lamp solution. The remediation of Hg2? from the extracted fluorescent lamp solution was investigated in a batch isotherm remediation system pertaining to pH, concentration, particle sizes, and contact time. The SFLs of different brands were collected from throughout Qatar. Two main types of SFLs were collected and tested; the T8 and T12. The SFL were scratched and the powder inside was carefully collected by brushing the inside of the lamps (approximately 100 g have been collected). Various reagents and materials were used for the mercury extraction experiments such as HCl, HNO3, and H2O2. The instruments and methods mainly adapted in these experiments were Cold Vapor Atomic Absorption Spectrophotometer (CVAAS) for the mercury analysis, incubator shaker to maintain constant shaking with temperature, microwave for the extraction enhancement, and oven. In the experiments, the ratios of HCl, HNO3, and H2O2 as extracting agents were carefully chosen to achieve the maximum exactable mercury. The collected date pits were roasted at 150°C for 5 h and the sulfur-modified roasted date pits was carried out to investigate the adsorption enhancement after modification. In order to study the impacts of different pH values on the adsorption, the FTIR spectra of the RODP and RODP at different pH values were recorded. The FTIR measurements were performed over 4000-400/cm. Scanning electron microscope (SEM) was also used to evaluate the surface morphology of the adsorbents using the JEOL model JSM-6390LV. After determining Hg2+ concentration in the extracted SFL solutions, various initial Hg2? concentrations were prepared. The residual Hg2+ in solution was analyzed after adsorption onto RODP. Different key parameters will also be performed such as the effect of pH, mass, and the solution temperature. From the initial results, we can conclude that the highest Hg adsorption occurred at pH 6 with almost 80% adsorption value. Moreover, at pH 8 and pH 10, the adsorption decreased with an average Hg concentration of 3.5 and 8.01 ppm, respectively. This decreasing in the adsorption capacity is due to the formation of mercury (II) hydroxide Hg(OH2) which forms a precipitation; resulting in decreasing the adsorption. However, pH 2 and pH 4, have average concentration of mercury equal to 18.8 and 18.3 ppm, respectively, which is very high concentration and it is over range. From the FTIR results we can determine the functional groups of the RODP which can determine the reactivity of the RODP towards mercury. According to the results obtained from CVAAS that pH 6 is the best pH for the adsorption process, functional groups found in the RODP having pH 6 are mainly hydroxyl and carboxyl acid which means that these functional groups have the highest ability to adsorb mercury more than other groups. Acknowledgement: This paper was made possible by UREP grant # (UREP17-066-1-004) from the Qatar national research fund (a member of Qatar foundation). The statements made herein are solely the responsibility of the author(s).qscienc

Global estimates on the number of people blind or visually impaired by cataract: a meta-analysis from 2000 to 2020

Background: To estimate global and regional trends from 2000 to 2020 of the number of persons visually impaired by cataract and their proportion of the total number of vision-impaired individuals. Methods: A systematic review and meta-analysis of published population studies and gray literature from 2000 to 2020 was carried out to estimate global and regional trends. We developed prevalence estimates based on modeled distance visual impairment and blindness due to cataract, producing location-, year-, age-, and sex-specific estimates of moderate to severe vision impairment (MSVI presenting visual acuity &lt;6/18, ≥3/60) and blindness (presenting visual acuity &lt;3/60). Estimates are age-standardized using the GBD standard population. Results: In 2020, among overall (all ages) 43.3 million blind and 295 million with MSVI, 17.0 million (39.6%) people were blind and 83.5 million (28.3%) had MSVI due to cataract blind 60% female, MSVI 59% female. From 1990 to 2020, the count of persons blind (MSVI) due to cataract increased by 29.7%(93.1%) whereas the age-standardized global prevalence of cataract-related blindness improved by −27.5% and MSVI increased by 7.2%. The contribution of cataract to the age-standardized prevalence of blindness exceeded the global figure only in South Asia (62.9%) and Southeast Asia and Oceania (47.9%). Conclusions: The number of people blind and with MSVI due to cataract has risen over the past 30 years, despite a decrease in the age-standardized prevalence of cataract. This indicates that cataract treatment programs have been beneficial, but population growth and aging have outpaced their impact. Growing numbers of cataract blind indicate that more, better-directed, resources are needed to increase global capacity for cataract surgery.</p

Global, regional, and national incidence of six major immune-mediated inflammatory diseases: findings from the global burden of disease study 2019

BACKGROUND: The causes for immune-mediated inflammatory diseases (IMIDs) are diverse and the incidence trends of IMIDs from specific causes are rarely studied. The study aims to investigate the pattern and trend of IMIDs from 1990 to 2019. METHODS: We collected detailed information on six major causes of IMIDs, including asthma, inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis, psoriasis, and atopic dermatitis, between 1990 and 2019, derived from the Global Burden of Disease study in 2019. The average annual percent change (AAPC) in number of incidents and age standardized incidence rate (ASR) on IMIDs, by sex, age, region, and causes, were calculated to quantify the temporal trends. FINDINGS: In 2019, rheumatoid arthritis, atopic dermatitis, asthma, multiple sclerosis, psoriasis, inflammatory bowel disease accounted 1.59%, 36.17%, 54.71%, 0.09%, 6.84%, 0.60% of overall new IMIDs cases, respectively. The ASR of IMIDs showed substantial regional and global variation with the highest in High SDI region, High-income North America, and United States of America. Throughout human lifespan, the age distribution of incident cases from six IMIDs was quite different. Globally, incident cases of IMIDs increased with an AAPC of 0.68 and the ASR decreased with an AAPC of −0.34 from 1990 to 2019. The incident cases increased across six IMIDs, the ASR of rheumatoid arthritis increased (0.21, 95% CI 0.18, 0.25), while the ASR of asthma (AAPC = −0.41), inflammatory bowel disease (AAPC = −0.72), multiple sclerosis (AAPC = −0.26), psoriasis (AAPC = −0.77), and atopic dermatitis (AAPC = −0.15) decreased. The ASR of overall and six individual IMID increased with SDI at regional and global level. Countries with higher ASR in 1990 experienced a more rapid decrease in ASR. INTERPRETATION: The incidence patterns of IMIDs varied considerably across the world. Innovative prevention and integrative management strategy are urgently needed to mitigate the increasing ASR of rheumatoid arthritis and upsurging new cases of other five IMIDs, respectively. FUNDING: The Global Burden of Disease Study is funded by the Bill and Melinda Gates Foundation. The project funded by Scientific Research Fund of Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital (2022QN38)