Discover and publish cutting edge, open research.

Browse 11,954 multi-disciplinary research preprints

Most recent

Vincent Chan

and 7 more

Chigozie NWACHUKWU

and 2 more

Between late December 2019 to early September 2020, over 10 million people globally were reportedly infected by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), responsible for the coronavirus disease-2019 (COVID-19). In Africa, more than 300,000 infection occurred within the period, from which several viral genetic sequences were generated. Phylogenetic reconstruction of genomic data can provide epidemiological inferences about time of pathogen introduction, epidemic growth rate and temporal-spatial spread of the infection during disease outbreak. In this work, we studied the genetic epidemiology of COVID-19 in Africa. Genetic sequence data of SARS-CoV-2 and metadata from African countries were obtained from open-source sequence database hosted by the GISAID initiative. Whole genome sequences were subjected to multiple sequence alignment, from which Maximum Likelihood phylogenetic tree was constructed based on the general time reversible model. Of the 227 genetic sequences obtained for 9 African countries (DRC=133, Senegal=23, South Africa=20, Ghana=15, Tunisia=6, Algeria=3, Gambia=3, Egypt=2 and Nigeria=2), 220 were whole genome sequences while 7 were partial genome sequences of the surface glycoprotein S. Phylogenetic analysis confirmed multiple introductions of the virus to the continent from multiple external sources prior to local adaptation and spread. The very close alignment of three viruses - Ghana/1659_S14/2020|EPI_ISL_422405, DRC/KN0054/2020|EPI_ISL_417437, and South_Africa/R05475/2020|EPI_ISL_435059 – to the reference Wuhan strain on the time tree, suggests possible introduction and circulation of the virus into the continent much earlier than when the first case was announced on February 15 2020. In conclusion, this study provided evidence to support multiple introductions of SARS-CoV-2 into Africa, and further suggests that the virus may have already been circulating in the continent prior to official reporting of the first case. Also, there is strong impression to infer likely genetic adaptation of the virus in the continent that may account for the close clustering of isolates from different countries.

Pavel Kvapil

and 9 more

Monitoring infectious diseases is one of the most important pillars of preventive medicine in zoological collections. Screening for parasitic and bacterial infections is obligatory for keeping animals and equipment safe from pathogens that may pose a risk to animal and human health. Zoological collections usually contain many different animal species, living in close proximity with people and wild animals. As an epidemiological probe, 188 animals (122 mammals, 65 birds, and one reptile) from a zoo in Slovenia were examined for selected pathogens. Antibodies to Toxoplasma gondii and Neospora caninum were detected by ELISA in 37% and 3% of mammals, and in 0% and 3% of birds, respectively; the reptile was negative. A statistically significant difference in T. gondii prevalence was found in Carnivora (78%) compared to Cetartiodactyla (33%, p = 0.0227) and Primates (25%, p = 0.0084). Antibodies to Encephalitozoon cuniculi were detected by IFAT in 55% of mammals and 34% of birds, respectively; the reptile was negative. Herbivores had a higher chance of being infected with E. cuniculi compared to omnivores (p = 0.0015). Antibodies to Chlamydia abortus and Coxiella burnetii were not detected in any of the zoo animals. The sera of 39 wild rodents found in the zoo were also examined; they were negative for all three parasites. The parasite T. gondii was detected by PCR in the tissue of two mute swans (Cygnus olor), one laboratory mouse, two Mus musculus, one Apodemus flavicollis, and one Apodemus agrarius. Positive samples were genotyped by a single multiplex PCR assay using 15 microsatellite markers; one sample from a mute swan was characterized as type II. This micro-epidemiological study offers a better understanding of pathogens in zoo animals and an understanding the role of zoos in biosurveillance.
Background: Pediatric B-Lymphoblastic lymphoma(pB-LBL) is a rare entity, and appropriate treatment for pB-LBL is not well defined. While intensive Acute Lymphoblastic leukemia(ALL) type regimens achieve long term event free survival of 90% across western co-operative group trials, published data from Asian studies on long term outcomes in pB-LBL are scarce. We evaluated the outcomes and prognostic factors of pediatric B-LBL patients treated at our center. Methods: We retrospectively analyzed the data of pediatric B-LBL patients treated between January 2010 and December 2017 on a uniform protocol(modified BFM 90). Patients were evaluated for early response post-induction and monitored for toxicity and long term outcomes. Kaplan-Meier method was used to estimate the event free survival(EFS) and overall survival(OS). Cox regression models were performed to identify prognostic factors. Results: Of 21 patients who received treatment on the modified BFM 90 protocol, 17(81%) were alive in remission, 3(14%) had relapse, and 1(4%) had treatment-related mortality(TRM) while in remission. Two of 3 relapsed patients subsequently expired. With a median follow-up of 66 months(range 6–114), 5-year Event free survival(EFS) and overall survival(OS) were 80%(95% CI:71–89%) and 91% (95% CI:85–97%), respectively. While delayed presentation (≥3 months) had inferior EFS(p-0.030), patients with elevated baseline Lactate Dehydrogenase(LDH) had a worse OS(p-0.037). Age, gender, site of origin, stage, and post-induction response had no bearing on outcome. Conclusions: Outcomes of pB-LBL patients treated on modified BFM 90 protocol are excellent. Higher disease burden manifested by elevated baseline LDH and delayed presentation(≥3 months) portend poorer survival.

Rajalakshmi K

and 3 more

Objective: to compare the vaginal birth rate in women with previous one lower segment caesarean section when induced at 40 weeks compared to expectant management till 41 weeks. Design: A randomized controlled trial Setting: Department of Obstetrics and Gynaecology, JIPMER, a tertiary care teaching institution in the south of India. Population or Sample: Low-risk women with previous one single lower segment caesarean section with a singleton foetus in vertex presentation and eligible for a trial of labour (TOLAC) at 40 weeks gestation. Methods: Block randomization to two groups of thirty each. The induction group was induced at 40 weeks with low dose oxytocin infusion or ripening with a single application of a single balloon Foley catheter followed by oxytocin infusion 24 hours later. The expectant group was managed in the hospital with maternal and foetal surveillance and induced at 41 weeks if they had not delivered by then. Main Outcome Measures: Vaginal birth after caesarean section (VBAC). Results: The demography and pregnancy variables were comparable in the two groups. Twenty out of thirty women (66.67%) had a successful vaginal birth after caesarean section in the induction group compared to ten out of 30 (33.33%) in the expectant group. This difference was significant (RR 2.0, 95% CI: 1.13-3.52; P=0.016) Conclusions: Among low-risk women with previous one lower segment caesarean section willing and eligible for TOLAC, the successful VBAC rate is significantly higher among those induced at 40 weeks compared to those managed expectantly till 41 weeks.

Mohammad El Tahlawi

and 4 more

Background: Congenital pulmonary stenosis (PS) is a progressive disease. Balloon pulmonary valvuloplasty (BPV) is the treatment of choice in valvular PS. Aim: We aim to study the relationship between biomarkers and echocardiographic markers in valvular PS and to assess the impact of BPV on these markers. Patients & Methods Patients with moderate and severe valvular PS amenable for BPV were recruited. Serum troponin I was measured. Echocardiographic assessment of PS and right ventricular (RV)function were done. All patients underwent BPV. Troponin level and echocardiographic data were re-assessed two weeks & six months after BPV. Results: Fifty patients with valvular PS were recruited. There was significant correlation between peak SPG and troponin (p < 0.001). Troponin was significantly decreased 2 weeks after BPV. Similarly, there was an initial improvement in RV function. After 6 months of follow up, we divided patients into 2 groups: Group-A: 36 patients with no restenosis. Group-B: 14 patients with restenosis. There were high significant differences between both groups regarding troponin level and RV functions with re-elevated troponin in group-B that correlated with peak PG (r= 0.9, p < 0.001). RV function parameters in group-B became significantly worse 6 months after BPV than those after the initial 2 weeks. Conclusion Troponin correlates with the severity of PS and associates with RV dysfunction. Both troponin & RV functions improved with BPV. Recurrent elevation of troponin and impairment of RV function are associated with PV restenosis and could be set as an indication for repeated balloon dilatation of PV.

Brian Kirsch

and 9 more

Browse more recent preprints

Recently published in scholarly journals

Oktay Ucer

and 3 more

Semih Ak

and 1 more

Background: Hookah is a tobacco product of Middle Eastern origin; however, its popularity increases in Europe and the US. Despite its frequent use, hookah’s potentially detrimental effects are underestimated due to the scarcity of the relevant research. Since septoplasty is one of the most commonly performed procedures of otolaryngology practice, we aimed to investigate the impact of hookah consumption on recovery after septoplasty. Methods: Patients who underwent septoplasty in Sanliurfa Training and Research Hospital Department of Otolaryngology between January 2017 and December 2019 were divided into four groups based on their history of hookah and cigarette smoking. The patients’ prospectively collected data, including demographic features, healing time, and presence or absence of septal perforation during follow-up, were compared between these four groups. Results: The entire cohort included 270 patients. The mean patient age was 29.2±5.8 years. One hundred and thirty-two (48.9%) patients were non-smokers, 96 (35.5%) were cigarette smokers, 27 (10%) were hookah smokers, and 15 (5.6%) consumed both tobacco products regularly. Mean healing time was 10 days, and septal perforation was encountered in 10 patients (3.7%). A comparison of the groups revealed that cigarette smoking did not impact septal perforation rates (p=0.326) but prolonged the healing time. However, hookah smoking with or without cigarette smoking significantly influenced septal perforation rates and healing times. Conclusion: Patients should be questioned about hookah smoking in addition to cigarette smoking before the septoplasty procedure. Patients with a positive history of hookah smoking should be followed closely in terms of delayed healing and increased septal perforation rates.

George Angelidis

and 3 more

COVID-19 and nuclear cardiology: Introducing the ‘’forward” virtual visit Angelidis G, Valotassiou V, Psimadas D, Georgoulias PNuclear Medicine Laboratory, University of Thessaly, Larissa, GreeceWe read with great interest the recent review article by Kaushik A, et al. concerning the potential role of digital health applications in the present pandemic situation [1]. As the authors noted, alternative tools are needed for the optimal management of cardiovascular patients, avoiding unnecessary visits to health care facilities. The severe acute respiratory syndrome – coronavirus – 2 (SARS-CoV-2) can invade the cardiovascular cells, potentially causing life-threatening cardiac impairment [2]. In particular, patients with pre-existing cardiovascular diseases are characterized by a higher risk of adverse cardiovascular events. Therefore, most of those referred for nuclear cardiology techniques are expected to be at higher risk of developing serious coronavirus disease 2019 (COVID-19) complications. However, the performance of the individually required diagnostic and follow-up procedures is important [3].Telemedicine applications have been used in public health emergencies, leading to several advantages in terms of safety and efficacy. In the field of nuclear cardiology, the initial evaluation of patients’ history and clinical features can take place remotely (‘’forward” virtual visit). This approach seems to be patient-centred (permitting an adequate case assessment) and conducive to self-quarantine (protecting patients, healthcare professionals, and the community from viral exposure). Importantly, possible clinical presentations of COVID-19 may be evaluated during the ‘’forward” virtual visit, as well as information regarding travel and exposure histories. Moreover, local epidemiological information may be used to adjust screening pattern, and special measures could be developed (such as isolation in dedicated ‘’hot” rooms) for patients with high-risk features. After the performance of the examination, telemedicine applications could be also used for the consultation with the patients.Telemedicine applications may contribute to a better adjustment of nuclear cardiology services under the current demanding circumstances. Of course, no telemedicine programme can be created overnight, but this approach may be of value not only during the next months but also after the end of COVID-19 pandemic [4]. For example, our nuclear medicine laboratory is located in central Greece providing services to inhabitants of mountain villages, and nearby small islands. Consequently, the use of telemedicine applications could aid our practice in the future as well, particularly during the winter months when travelling by car or sea travels may be extremely demanding.

Attila Mokánszki

and 8 more

Background Retinoblastoma (Rb) is a malignant tumor of the developing retina that affects children before the age of five years in association with inherited or early germline mutations of the RB1 gene. The genetic predisposition is also related with second primary malignancies arising de novo, or following radiotherapy which have become the leading cause of death in retinoblastoma survivors. Procedure We describe a retinoblastoma case with a novel RB1 and a synchronous MET aberration. Our goal was to identify all germline and somatic genetic alterations in available tissue samples from different time periods and to reconstruct their clonal relations using next generation sequencing (NGS). We also used structural and functional prediction of the mutant RB and MET proteins to find interactions between the defected proteins with potential causative role in the development of this uniqe form of retinoblastoma. Results In this study we detected a retinoblastoma case of non-parental origin with a novel RB1 c.2548C>T;p.(Gln850Ter) and a synchronous MET c.3029C>T;p.(Thr1010Ile) germline mutations. Following bilateral retinoblastoma the boy further developed at least four different manifestations of two independent osteosarcomas. Both histopathology and NGS findings supported the independent nature of a chondroblastic osteosarcoma of the irradiated facial bone followed by an osteoblastic sarcoma of the leg (tibia). Conclusions Because of the expanding number of registered Rb cases, the novel rare cases publication is very important to understand the molecular mechanism of this malignancy. We reported a novel form of Rb and consequential chondroblastic and osteoblastic osteosarcoma, the latter one developing pulmonary metastatses.

Ugur Balkanci

and 2 more

An Unusual Case of Necrotizing Pneumonia Presenting with Acute Kidney InjuryUgur Berkay Balkanci, MDSchool of Public Health, University of Minnesota, Minneapolis, MNDavid J. Sas, DODivision of Pediatric Nephrology and Hypertension, Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Rochester, MinnesotaNadir Demirel, MDDivision of Pediatric Pulmonology, Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Rochester, MinnesotaCorresponding Author:Nadir Demirel, MDDivision of Pediatric Pulmonology200 First Street SWRochester, MN 55906Tel. No.: 5075380754Fax No.: 5072840727Demirel.nadir@mayo.eduKey words: postinfectious glomerulonephritis, pneumothorax, complications, complicated pneumoniaFinancial Disclosure: The authors have indicated they have no financial relationships relevant to this article to disclose.Funding: No external funding.Short title: “An unusual case of necrotizing pneumonia”To the Editor:Lower respiratory tract infections are the most common reason for hospitalization in the pediatric age group in the United States. Although pneumonia is prevalent, complicated pneumonia such as empyema, lung abscess and necrotizing pneumonia (NP) is uncommon in children1. The prevalence of complicated pneumococcal pneumonia decreased significantly after the introduction of the thirteen-valent pneumococcal vaccine in 20101. NP in the pediatric population is a severe disease characterized by extensive destruction and liquefaction of the lung tissue resulting in loss of the pulmonary parenchymal architecture, cavitation of the lung, and pleural involvement. Renal complications of complicated pneumonia are rare and mostly reported as atypical hemolytic uremic syndrome (HUS)2. Post-infectious glomerulonephritis (PIGN) is an unexpected complication of bacterial pneumonia3.We report a six-year-old otherwise healthy fully vaccinated girl with a 4-day history of fever, abdominal pain, vomiting, non-bloody diarrhea, and poor oral intake. Parents reported decreased urine output and dark-colored urine on the day of admission. Initial evaluation revealed serum creatinine of 5.01 mg/dL and blood urea nitrogen of 86 mg/dL, elevated acute phase reactants suggesting acute kidney injury (AKI) in the setting of an undiagnosed acute infectious process. The patient was admitted with decreased effective circulatory volume. Urinalysis revealed hematuria with <25% dysmorphic red blood cells (RBCs), proteinuria, pyuria, and RBC casts and granular casts, suggestive of acute glomerulonephritis.She was started on intermittent hemodialysis at day 2 of admission to address uremia, fluid overload, and hyperphosphatemia. A renal biopsy revealed diffuse exudative glomerulonephritis, consistent with infection-related glomerulonephritis. ASO, Anti-DNase B were negative; C3, C4 levels were low. She was treated with pulse IV methylprednisolone 10mg/kg/day for three days. The first 5 days in the hospital, the patient remained afebrile and her lung exam was normal without respiratory symptoms.On day six of admission, she developed acute right-sided chest pain and shortness of breath during hemodialysis. Chest x-ray (CXR) revealed a large right-sided tension pneumothorax, prompting therapeutic chest tube placement. Repeat CXR revealed reexpansion of the right lung and a significant right upper lobe consolidation with an ovoid hyperlucency and an air-fluid level. A chest CT scan confirmed the diagnosis of NP with multiple cavities (Image).Flexible bronchoscopy was performed with bronchoalveolar lavage revealing 42% neutrophils and negative cultures. She was treated with broad spectrum intravenous antibiotics.During admission, she developed hypertension, well-controlled with scheduled enalapril and amlodipine, as well as isradipine as needed. On day 14 of admission, hemodialysis was discontinued as kidney function improved, and chest tube was removed. She was discharged at day 26 of admission on intravenous ceftriaxone and oral metronidazole to complete 30 days of treatment. A repeat chest CT at end of treatment showed complete resolution of NP. Renal functions and blood pressure normalized on follow up.NP is characterized by persistent high fevers and prolonged hospitalizations even with appropriate antibiotic treatment1. Most often, NP affects immunocompetent children with no underlying risk factors4. The pathophysiology of this complication is acute liquefactive necrosis of the lung parenchyma which results in the development of pneumatoceles4. The most common pathogen causing NP is Streptococcus pneumoniae followed by Staphylococcus aureus and Streptococcus pyogenes. Other rarer bacterial and viral pathogens are Mycoplasma pneumonia, Influenza, and Adenovirus1. Identifying the microbiologic pathogen can be challenging and is only made in 50% of cases1. In our case, we did not isolate the causative microorganism. NP typically resolves without residual morbidity, even after a protracted course1,4.Pleural involvement is almost universal in NP, and the course of pleural disease often determines duration and outcome, particularly as it relates to the complication of bronchopleural fistula (BPF)1. BPF is most likely due to the necrotic development of a connection between bronchial space and pleural space4. BPF formation is associated with a significantly longer hospital stay in children with NP4. Yet, most cases heal without surgical intervention4. Tension pneumothorax has been observed as a rare complication of NP1.Renal involvement in complicated pneumonia is rare. Atypical HUS has been reported as a complication of pneumonia, particularly associated with empyema. (most commonly due to invasive Streptococcus pneumoniae)2. In a case series of 37 cases of atypical HUS, 34 patients (92%) had pneumonia with 10 patients (29%) with NP5. Less commonly, pneumonia can be associated with PIGN. PIGN is the most common glomerulonephritis in children worldwide. Pneumonia-associated PIGN is rare. In a case series from the US, PIGN accounted for 0.15% of admissions for pneumonia and 0.39% of admissions for glomerulonephritis6. Pneumonia-associated PIGN is known to be caused by various bacterial pathogens including Streptococcus pneumoniae, Staphylococcus aureus, Mycoplasma pneumoniae, Chlamydia pneumoniae, Nocardia, and Coxiella burnetii3. Different from the usual presentation of the PIGN (in which the time interval between a pharyngeal group A Streptococcal infection and PIGN is 6 to 10 days), pneumonia-associated PIGN is usually concomitant with the pulmonary disease3,6.Our case is unusual in several ways: pneumonia-associated PIGN typically presents with respiratory symptoms first, and acute kidney injury developing during the course of pneumonia3. More surprisingly, the patient developed NP which is characterized by even more severe respiratory symptoms1. Yet, our patient presented without respiratory complaints and pneumonia became apparent only after the development of pneumothorax. We could only identify 2 cases of pneumonia-associated PIGN who presented with renal involvement before pulmonary complaints6,7. Also, previous cases in the literature of pneumonia-associated PIGN report mostly a non-complicated course of pulmonary disease3,6. In a case series of 11 children with pneumonia-associated PIGN, only one case developed a small empyema6. Similarly, the majority of the reported cases of pneumonia-associated PIGN describe a benign course of renal disease3,6. Our patient’s kidney failure progressed rapidly, and she required 2 weeks of intermittent hemodialysis and a three-day course of pulse steroid therapy. At present, systemic corticosteroids are not recommended for patients with complicated pneumonia. A Cochrane review including 17 randomized controlled trials, of which four were conducted on children, found that corticosteroid therapy reduced mortality and morbidity in adults with severe CAP, and morbidity, but not mortality, in adults and children with non-severe CAP1. We speculate that pulse steroid treatment may have modified the course of NP in our patient.This case suggests an atypical presentation of NP with predominant renal complications is possible. Pediatricians should be aware of renal complications of respiratory diseases. Systemic steroids should be considered in the treatment of NP.References:1. de Benedictis FM, Kerem E, Chang AB, Colin AA, Zar HJ, Bush A. Complicated pneumonia in children. Lancet 2020;396:786-798.2. Spinale JM, Ruebner RL, Kaplan BS, Copelovitch L. Update on Streptococcus pneumoniae associated hemolytic uremic syndrome. Curr Opin Pediatr 2013;25:203-208.3. Carceller Lechón F, de la Torre Espí M, Porto Abal R, Écija Peiró JL. Acute glomerulonephritis associated with pneumonia: a review of three cases. Pediatr Nephrol 2010;25:161-164.4. Sawicki GS, Lu FL, Valim C, Cleveland RH, Colin AA. Necrotising pneumonia is an increasingly detected complication of pneumonia in children. Eur Respir J 2008;31:1285-1291.5. Banerjee R, Hersh AL, Newland J, Beekmann SE, Polgreen PM, Bender J, Shaw J, Copelovitch L, Kaplan BS, Shah SS. Streptococcus pneumoniae-associated Hemolytic Uremic Syndrome Among Children in North America. Pediatr Infect Dis J 2011;30:736-739.6. Srivastava T, Warady BA, Alon US. Pneumonia-associated acute glomerulonephritis. Clin Nephrol 2002;57:175-182.7. Schachter J, Pomeranz A, Berger I, Wolach B. Acute glomerulonephritis secondary to lobar pneumonia. Int J Pediatr Nephrol 1987;8:211-214.

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 collections
Explore More Collections

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