Discover and publish cutting edge, open research.

Browse 22,090 multi-disciplinary research preprints

Most recent

Arezoo Khalili

and 3 more

Multi-phenotypic screening of multiple zebrafish larvae plays an important role in enhancing the quality and speed of biological assays. Many microfluidic devices have been presented for zebrafish phenotypic assays, but multi-organ screening of multiple larvae, from different needed orientations, in a single device that can enable rapid and large-sample testing is yet to be achieved. Here, we propose a multi-phenotypic quadruple-fish microfluidic chip for simultaneous monitoring of fin movement and heart activity of 5–7-day postfertilization zebrafish larvae trapped in the chip. In each experiment, fin movements of four larvae were quantified in the dorsal view in terms of fin beat frequency (FBF). Positioning of four optical prisms next to the traps provided the lateral views of the four larvae and enabled heart rate (HR) monitoring. The device’s functionality in chemical testing was validated by assessing the impacts of ethanol on heart and fin activities. Larvae treated with 3% ethanol displayed a significant drop of 13.2% and 35.8% in HR and FBF, respectively. Subsequent tests with cadmium chloride highlighted the novel application of our device for screening the effect of heavy metals on cardiac and respiratory function at the same time. Exposure to 5 μg/L cadmium chloride revealed a significant increase of 8.2% and 39.2% in HR and FBF, respectively. The device can be employed to improve quantitative multi-phenotypic screening of zebrafish larvae in response to chemical stimuli in various chemical screening assays, in applications such as ecotoxicology and drug discovery.

Browse more recent preprints

Recently published in scholarly journals

Yuval Shafir

and 8 more

INTRODUCTION: Transvenous Lead Extraction (TLE) is usually performed via a superior approach. Predictors and outcomes of TLE requiring femoral vein bailout are poorly defined. We aimed to analyze predictors and consequences of TLE requiring femoral bailout. METHODS: A single tertiary center cohort of 421 consecutive patients who underwent TLE between May 2010 and February 2020 were analyzed. Venography was routinely performed before system upgrade to identify occluded veins. Patients were divided into 2 groups according to their need for femoral bailout extraction. RESULTS: A total of 928 leads were extracted with femoral bailout approach was needed in 71 leads(7.7%) among 49 patients(11.6%). A higher proportion of right ventricular(RV) leads required femoral bailout approach compared with right atrial(RA) leads[51/499(10.2%) vs 18/326(5.5%);p=0.02]. Femoral bailout was more common among younger patients, longer lead dwell time, more pocket entries, higher number of extracted leads, presence of abandoned leads and among patients with vascular occlusion. Following multivariate analysis, presence of abandoned leads, vascular occlusion and younger age remained a significant predictor for femoral bailout. Femoral bailout resulted in higher rates of major complications [5/49(10.2%) vs 12/372(3.2%);p=0.05] without intra-procedural mortality and no additional 30-day mortality[2/49(4.1%) vs 33/377(8.8%);p=0.39]. CONCLUSION: TLE of abandoned leads, occluded veins and younger age were found to be predictors of femoral bailout requirement. Despite higher rates of major complications in femoral TLE bailout, mortality was not increased. Venography prior to TLE should be considered for procedure planning.

Manuel E. Izquierdo

and 21 more

Background:  Heterozygote carriers of potentially pathogenic variants in the cystic fibrosis transmembrane conductance regulator ( CFTR) gene have increased asthma risk. However, the frequency and impact of CFTR variation among individuals with asthma is unknown. Objective: To determine whether potentially pathogenic  CFTR variants associate with disease severity and whether individuals with two potentially pathogenic variants exist in a severe asthma-enriched cohort . Methods: We analyzed sequencing data spanning a 190.5Kb region of  CFTR in participants from the Severe Asthma Research Program (SARP1-3). Potentially pathogenic, rare  CFTR variants (frequency<0.05) were classified as CF-causing or of varying clinical consequences (VVCC) (CFTR2.org). Regression-based models tested for association between  CFTR genotypes (0-2 potentially pathogenic variants) and severity outcomes. Results: Of 1401 participants, 9.5% (134) had one potentially pathogenic variant, occurring more frequently in non-Hispanic white (NHW, 10.1% [84 of 831]) compared to African American individuals (AA, 5.2% [22 of 426]). We found ≥2 potentially pathogenic  CFTR variants in 1.4% (19); 0.5% (4) of NHW and 2.8% (12) of AA. Potentially pathogenic  CFTR variant genotypes (≥1 or ≥2 variants) were not cumulatively associated with lung function or exacerbations. In NHW, we found three F508del compound heterozygotes with F508del and a VVCC (two 5T;TG12[c.1210-11T>G] and one Arg1070Trp) and a homozygote for the VVCC, 5T;TG12. Conclusions: We found potentially pathogenic  CFTR variants within a severe asthma-enriched cohort , including three compound heterozygote genotypes variably associated with CF in NHW individuals. These findings provide the rationale for  CFTR sequencing and phenotyping of CF-related traits in individuals with severe asthma.

Hanan Al-Abboh

and 2 more

A Novel MECOM Variant Associated with Congenital Amegakaryocytic Thrombocytopenia and Radioulnar Synostosis Hanan Al-Abboh1, Akmal Zahra1 and Adekunle Adekile1,2Pediatric Hematology Unit, Mubarak Hospital1 and Department of Pediatrics, Faculty of Medicine, Kuwait University2, Kuwait Address Correspondence to: Professor Adekunle Adekile Department of Pediatrics Faculty of Medicine Kuwait University PO Box 24923 Safat 13110 Kuwait Email: adekunle.adekile@ku.edu.kw Tel: +96525319486To the EditorCongenital radioulnar synostosis (RUS) is a rare developmental anomaly of proximal fusion of the radius and ulna, resulting in limited pronation and supination of the forearm. It may accompany other abnormalities in the skeleton, kidney, heart and aneuploidy syndromes1,2. A subset of patients with RUS present with bone marrow failure (BMF) syndromes, characterized by amegakaryocytic thrombocytopenia (RUSAT), progressing to myelodysplasia and pancytopenia2,3. The hematological manifestations are quite variable, with some presenting with severe BMF in childhood, while others are mild and may not present until adulthood.Heterozygous germline variants in the homeobox A11 (HOXA11) gene were the first to be associated with RUS and designated RUSAT14, but lately, several families have been described with variants in the MDS1 and EVI1 complex (MECOM) locus, and referred to as RUSAT22,5,6. Many of these variants appear de novo , while others follow an autosomal dominant inheritance. We, hereby, report the case of a Kuwaiti patient who presented with congenital amegakaryocytic thrombocytopenia (CAMT) in the neonatal period and later noticed to have RUS. Whole exome sequencing revealed a novel MECOM variant.A.A. is a male Kuwaiti, the first child of consanguineous parents and was first seen at the age of 36 days, following antenatal ultrasound diagnosis of bilateral hydronephrosis and right renal cyst. He was a product of induced vaginal delivery with a birth weight of 2.3 kg. After delivery, he was kept under observation in the neonatal intensive care unit. His CBC showed isolated thrombocytopenia (Plt 34 x109/L). He received several platelet transfusions, as well as IVIG twice. Postnatal abdominal ultrasound showed multicystic right kidney, in addition to bilateral hydronephrosis. The mother had no history of thrombocytopenia during pregnancy and there was no other pertinent family history.Physical examination at presentation showed 2 café-au-lait spots, one on the back, measuring 1x2 cm and another over the left leg, that was less than 0.6 cm. There were no obvious dysmorphic features and other systems were unremarkable. CBC showed WBC 11.2 x109/L Hb 10.4 g/dL, MCV 83fl, Plt 49 x109/L, ANC 1.8 x109/L. Renal function tests were normal. Blood film showed no abnormal cells; there was true thrombocytopenia with giant forms. Antiplatelet antibody was negative. Abdominal ultrasound at age 1 month showed complete replacement of the right kidney by cystic changes with left moderate hydronephrosis. Skeletal survey was reportedly normal.Bone marrow biopsy showed normal distribution of granulocytic and erythroid precursors, with severe suppression of megakaryocytosis, consistent with a bone marrow failure syndrome. Chromosomal breakage study was normal. The patient was diagnosed with right undescended testis, as well as right inguinal hernia that were operated at age 1 year and 10 months. At the age 2 and a half years, A.A. was noticed to have limited bilateral arm movement supination and pronation. The mother volunteered that she has a similar defect. X-rays confirmed that the child had bilateral radioulnar synostosis. Whole exome sequencing showed that the patient is heterozygous for a previously-unreported MECOM gene, c.2282A>G mutation. Unfortunately, the parents have not been screened for these mutations.The patient has been under follow up for 4 years, his platelet count has been stable, ranging between 40-50 x109/L, with no bleeding tendency. In spite of his limited arm rotation, he currently functions normally in his daily activities, however, his hand writing skills and ability to engage in sports are yet to be observed since he is still pre-school age. Platelet transfusion is reserved only for severe bleeding, which he has not had. Bone marrow transplant may be considered in future if his bone marrow failure worsens and/or his marrow shows dysplastic changes.Dokal et al3 were the first to report an association between RUS and late-onset BMF, while Thompson et al described its association with CAMT and linked it to the c.872delA ,p.Asn291Thrfs3 variant of the HOXA11gene4,7. More recently, several germline mutations in the MECOM locus have been reported and appear to be the more common cause of RUSAT. Indeed, no other cases of HOXA11 mutations linked to RUSAT have been described since the initial report. Niihori et al8 reported the first 3 heterozygous MECOMmutations in 3 sporadic patients. These variants and those subsequently reported by Walne et al2 are in a highly conserved cluster within 10 amino acids (aa750-760) and impact on either the highly conserved Cys2His2 zinc finger motif (zinc finger 8, aa733-755) or the adjacent linker motif (aa756-760). It has been shown that removal of the 8th zinc finger causes granulopoiesis arrest while mutations and deletions in other parts of the complex, outside the 8th and 9th fingers, are associated with hematological disorders without RUS9.MECOM codes for a zinc finger transcription factor with important roles in normal development and oncogenesis and is involved in the regulation of embryonic development and hematopoietic stem-cell renewal. Hence the phenotype in individuals with these mutations is very variable ranging from BMF to different skeletal, cardiac, renal malformations, B cell deficiency and sensorineural deafness.Our patient showed a previously unreported variant in the region of the 8th zinc finger of the MECOM locus. This c.2282A>G missense variant results in the tyrosine to cysteine substitution at codon 761 (p.Tyr761Cys). The amino acid is in the Zinc finger, C2H2 and Zinc finger, C2H2-like protein domains and is highly evolutionarily conserved. Unfortunately, the parents were not screened for the mutation, however, the mother shows RUS, with normal blood counts. This is consistent with the marked variability in the clinical phenotype. The father is also physically and hematologically normal.Apart from thrombocytopenia, our patient also had renal abnormalities – hydronephrosis and multicystic kidney disease. The natural history of his condition is that he may develop pancytopenia and/or myelodysplasia in the future. He is under close follow up and will be considered for bone marrow transplantation if his condition worsens. In the meantime, he remains hypomegakaryocytic with a platelet count at 30 – 50 x 109/l while other blood cellular elements are normal. His renal function and hearing are being monitored, but still remain normal.AcknowledgementsWe thank the patient’s family for allowing us to report this case. The whole exome sequencing was done at the Laboratory of Genetics and Genomics, Cincinnati Children’s Hospital, Cincinnati, Ohio.References1. Rizzo R, Pavone V, Corsello G, Sorge G, Neri G, Opitz JM. Autosomal dominant and sporadic radio-ulnar synostosis. Am J Med Genet.1997;68(2):127-134.2. Walne A, Tummala H, Ellison A, et al. Expanding the phenotypic and genetic spectrum of radioulnar synostosis associated hematological disease. Haematologica. 2018;103(7):e284-e287.3. Dokal I, Ganly P, Riebero I, et al. Late onset bone marrow failure associated with proximal fusion of radius and ulna: a new syndrome.Br J Haematol. 1989;71(2):277-280.4. Thompson AA, Nguyen LT. Amegakaryocytic thrombocytopenia and radio-ulnar synostosis are associated with HOXA11 mutation. Nat Genet. 2000;26(4):397-398.5. Germeshausen M, Ancliff P, Estrada J, et al. MECOM-associated syndrome: a heterogeneous inherited bone marrow failure syndrome with amegakaryocytic thrombocytopenia. Blood Adv. 2018;2(6):586-596.6. Ripperger T, Hofmann W, Koch JC, et al. MDS1 and EVI1 complex locus (MECOM): a novel candidate gene for hereditary hematological malignancies. Haematologica. 2018;103(2):e55-e58.7. Thompson AA, Woodruff K, Feig SA, Nguyen LT, Schanen NC. Congenital thrombocytopenia and radio-ulnar synostosis: a new familial syndrome.Br J Haematol. 2001;113(4):866-870.8. Niihori T, Ouchi-Uchiyama M, Sasahara Y, et al. Mutations in MECOM, Encoding Oncoprotein EVI1, Cause Radioulnar Synostosis with Amegakaryocytic Thrombocytopenia. Am J Hum Genet.2015;97(6):848-854.9. Nielsen M, Vermont CL, Aten E, et al. Deletion of the 3q26 region including the EVI1 and MDS1 genes in a neonate with congenital thrombocytopenia and subsequent aplastic anaemia. J Med Genet.2012;49(9):598-600.

Hoda Abdelgawad

and 2 more

57-years old man presented with exertional dyspnea. An early systolic murmur was heard over the aortic areas 2D and 3D Echocardiography revealed unicuspid , unicommissural aortic valve (UAV) with a characteristic “teardrop” lateral orifice (Figure A) and moderate valve stenosis (3D planimetered aortic valve area (AVA) is 1.1cm2) (Figure B) Continuous wave Doppler across aortic valve (AV) showed high peak and mean systolic gradients of 85 and 60mmHg respectively.(Figure C). 2D /3D Transesophageal Echocardiography (TOE) revealed a subaortic ridge attached to the posterior annulus (Arrow) (Figure D) Further En-face viewing of the aortic valve from the left ventricular outflow tract (LVOT) perspective showed a shelf-like ridge extending from the commissure to the cusp (Arrow) (Figure E) Zoomed mode of the aortic- LVOT junction confirmed the presence of the subaortic ridge seen attached to the posterior aortic annulus near the commissural opening (Figure F) The patient was referred for surgical consultation .. Unicupid aortic valve (UAV) is a rare congenital anomaly that has.2 subtypes ; unicomissural and acommissural subtypes. Both can present with variable degrees of the aortic stenosis (AS) and/or aortic valve regurgitation (AR).UAV has more early, accelerated and severe valvular degeneration in addition to smaller orifice in comparison with bicuspid and tricuspid aortic valve. Echocardiography is the gold standard for diagnosis and evaluation of the AV morphology and function and the associated disorders such as ventricular septal defect , aortopathy and subaortic obstruction.. Surgical aortic valve replacement (AVR) and repair of the associated anomalies are the most common treatment modality .

Esin Isik

and 7 more

Browse more published preprints

How it works

Upload or create your research work
You can upload Word, PDF, LaTeX as well as data, code, Jupyter Notebooks, videos, and figures. Or start a document from scratch.
Disseminate your research rapidly
Post your work as a preprint. A Digital Object Identifier (DOI) makes your research citeable and discoverable immediately.
Get published in a refereed journal
Track the status of your paper as it goes through peer review. When published, it automatically links to the publisher version.
Learn More
Featured communities
Explore More Communities

Other benefits of Authorea

Multidisciplinary

A repository for any field of research, from Anthropology to Zoology

Comments

Discuss your preprints with your collaborators and the scientific community

Interactive Figures

Not just PDFs. You can publish d3.js and Plot.ly graphs, data, code, Jupyter notebooks

Featured templates
Featured and interactive
Journals with direct submission
Explore All Templates