1,720,977 research outputs found
Simple and Multiplexed Detection of Nucleic Acid Targets Based on Fluorescent Ring Patterns and Deep Learning Analysis
No full textSimple diagnostic tests for nucleic acid targets can provide great advantages for applications such as rapid pathogen detection. Here, we developed a membrane assay for multiplexed detection of nucleic acid targets based on the visualization of two-dimensional fluorescent ring patterns. A droplet of the assay solution is applied to a cellulose nitrate membrane, and upon radial chromatographic flow and evaporation of the solvent, fluorescent patterns appear under UV irradiation. The target nucleic acid is isothermally amplified and is immediately hybridized with fluorescent oligonucleotide probes in a one-pot reaction. We established the fluorescent ring assay integrated with isothermal amplification (iFluor-RFA = isothermal fluorescent ring-based radial flow assay), and feasibility was tested using nucleic acid targets of the receptor binding domain (RBD) and RNA-dependent RNA polymerase (RdRp) genes of SARS-CoV-2. We demonstrate that the iFluor-RFA method is capable of specific and sensitive detection in the subpicomole range, as well as multiplexed detection even in complex solutions. Furthermore, we applied deep learning analysis of the fluorescence images, showing that patterns could be classified as positive or negative and that quantitative amounts of the target could be predicted. The current technique, which is a membrane pattern-based nucleic acid assay combined with deep learning analysis, provides a novel approach in diagnostic platform development that can be versatilely applied for the rapid detection of infectious pathogens.
Clinical significance of increased bone marrow uptake in 18FDG PET (Positron Emission Tomography) of chi
No full text의학과/석사[한글]목적: 18FDG PET은 최근 비호지킨림프종 환자에서 병기의 결정, 치료 반응의 평가와 잔류 종양의 진단 등에 있어, 종양 세포의 기능적 측면을 반영한 비침습적 영상 도구라는 점에서 뇌 자기 공명 영상, 컴퓨터 단층 촬영 및 초음파를 포함한 기존의 영상 도구를 보조할 뿐만 아니라 오히려 민감도와 특이도가 높다고 보고되고 있다. 림프종으로 진단 받은 환자에 있어 병기를 결정하는 것은 적절한 치료 방법의 선택, 치료 후 효과를 판정, 또는 추적 관리하는 데 기초가 된다는 중요성 이외에도 예후를 결정하는 요소라는 데 있어 의미가 크다. 성인 비호지킨림프종과는 달리 소아 비호지킨림프종은 상대적으로 고단계인 3-4기의 병기에 해당하는 환자가 많아 정확한 병기의 결정이 무엇보다 중요하다. Murphy 분류법에 따르면 소아 비호지킨림프종의 병기 결정에서 3기와 4기를 구분짓는 것은 골수침범 또는 중추신경계의 침범 유무인데, 현재까지 골수 침범 여부를 확인하는 방법으로 양측 장골능 골수 생검이 절대적 표준으로 이용되어 왔다. 최근까지 소아 비호지킨림프종의 병기 결정은 기존의 영상 도구에 의존하였으나 18FDG PET이 도입되면서 기능적 측면을 이용한 비침습적인 도구라는 장점을 이용하여 보다 정확한 병기의 결정에 도움이 되고 있다. 성인에서는 이러한 측면에 근거하여 18FDG PET의 역할에 관해 다양한 연구가 이루어지고 있으나, 소아 비호지킨림프종에서는 거의 보고된 바가 없으며, 국내에서는 더욱 미미한 상태이다. 이에 본 연구는 소아 비호지킨림프종 환자에서 18FDG PET이 병기 결정과 치료에 어떠한 역할을 하는지 고찰해보고자 한다.방법: 연세대학교 의과대학 세브란스병원 소아혈액종양과에서 소아 비호지킨 림프종으로 진단받은 환자들 중 18FDG PET이 시행된 시점인 2003년 1월을 기준으로, 1988년부터 2002년 12월까지 진단받은, 진단 당시 18FDG PET 을 시행하지 않은 환아 56명과, 2003년 1월부터 2008년 12월까지 진단 당시 18FDG PET을 시행한 환아 40명을 대상으로 의무기록과 검사 결과를 검토하였다. 또한 18FDG PET을 진단 당시에 시행한 환아군과 시행하지 않은 환아군 사이의 생존률을 통계 분석에 의해 비교하였다.결과: 진단 당시에 후장골능 골수 흡인 및 생검과 더불어 18FDG PET을시행한 2003년 1월부터 2008년 12월까지 비호지킨림프종으로 진단받은 총 40명의 환아들 중 29명에서 골수 생검의 결과와 18FDG PET의 결과가 일치하였다. 두 결과가 일치하지 않는 11명의 환아 중 1례에서는 골수 생검 결과상 골수 침범이 확인되었으나 18FDG PET에서는 골수 침범이 없는 것으로 나타났으며, 나머지 10명은 골수 생검 결과 음성이었으나 18FDG PET에서는 침범이 의심되었던 경우였다. 이 10명의 환자 중 2례에서는 골수 검사 결과에 따라 3기에 준한 항암화학요법을 시행하였고, 7례에서는 18FDGPET의 결과에 따라 병기를 4기로 결정하고 치료 방침에 따라 항암 화학요법을 시행하였으며, 나머지 1례에서는 두 결과에 차이가 있었으나 중추신경계 침범이 확인되어 4기에 준한 항암화학요법을 시행하였다. 이 결과는고식적인 방법에만 의존하여 3기로 병기 결정이 된 환자 28명 중 7명(25%)에서 18FDG PET 을 시행하였을 때 골수 침범 여부에 대해 불일치하였음을 의미한다. 치료 결과에 따른 대조군 설정을 위하여 18FDG PET 검사를 시행하기 이전인 1988년 1월부터 2002년 12월까지 소아 비호지킨림프종으로 진단받은 환아군 중에서 고식적인 영상진단 검사와 임상 검사 결과를 통해 3기로 진단받은 환아들의 5년 생존율은 51.5±10.4%이었으며, 그 이후 18FDG PET을 시행하였고, 임상적 병기로는 3기로 진단받은 환아들의5년 생존율은 96.4±3.4% 이었다. 두 군 사이에 log 회귀법을 시행하였고,P =.005로 통계적으로 유의미한 소견을 보였다. 이와 더불어 4기로 진단받은 환아들에서도 5년 생존율을 비교하였다. 18FDG PET 시행 이전 4기로 진단받은 환자군의 5년 생존율은 72.2±10.6%이었고, 18FDG PET 시행 이후 4기로 진단받은 환자군에서는 65.3±19.9%이었다. 두 군 사이에 log 회귀법을 시행하였고, P =.568로 통계적으로 무의미한 소견을 보였다.결론: 18FDG PET 검사를 통해 고식적인 영상 진단 및 골수 흡인 생검만으로 임상적 병기 3기에 해당하던 환자군에서 18FDG PET을 추가적으로 시행하여 전신 골수의 섭취 증가 소견을 확인할 수 있었으며, 이에 따라 7명의 환자에서 4기에 준한 치료를 시행한 것이 이전에 18FDG PET을 시행하지 않았던 3기 환자군과 비교하여 생존율의 차이 (51.5±10.4% 대 96.4±3.4%, P =.005)를 보였으며, 이는 통계학적으로 유의한 수준이었다. 이에 따르면 18FDG PET검사는 골수 검사가 전체 골수의 극히 일부만을 평가하게 됨으로써 종양 침범의 가능성을 간과하게 되는 취약점을 보완함으로써 정확한 병기 결정에 도움이 되고 궁극적으로 합당한 치료가 시행되어 생존율을 향상시키는 데 도움이 될 수 있음을 시사하는 것으로 사료된다.
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Characterizing neuroanatomical changes in parvalbumin and perineuronal nets in a rat DISC-1 knock out model
Get PDFBACKGROUND: Schizophrenia is a debilitating disorder that has a profound impact on quality of life due to the presence of both cognitive deficits and psychotic symptoms. Despite having significant global economic and social costs and a worldwide prevalence of 1%, schizophrenia is still not well understood. Research has been making strides in uncovering the pathophysiology and the etiology that drive this disease, ranging from genetic abnormalities, disrupted circuitry, changes in microarchitecture, to impaired synaptic connectivity. Evidence suggests that disrupted-in-schizophrenia-1 (DISC1) driven genetic disturbances in fast-spiking parvalbumin (PV) neurons and their surrounding perineuronal nets (PNNs) likely contribute to schizophrenia etiology as they are part of the microcircuits required for working memory, a cognitive function that has been consistently impaired in schizophrenic patients.
OBJECTIVE: To identify the neuroanatomical changes in PV neurons and surrounding PNNs in the superficial and deep layers of the prelimbic and infralimbic prefrontal cortex of a rat DISC-1 knockout model.
METHODS: 19 DISC1-KO male rats and 15 wildtype rats were treated with saline or MK-801. They were sacrificed between P268-269 and brains were extracted and separated at the corpus callosum. After fixing and preserving, the brains were sliced then stained to visualize parvalbumin and perineuronal nets with immunohistochemistry. Slices were imaged and analyzed for PV, PNN, and PV+PNN counts in the superficial and deep regions of the prelimbic and infralimbic cortices. Averages counts within each group were taken and analyzed via 2-way ANOVAs for each brain region and dependent variable.
RESULTS: DISC1-KO rats displayed the following trending changes: decreased PV cells in deep layers of infralimbic and decreased PNNs throughout the prelimbic cortex. MK-801 appears to increase the number of unsheathed PV cells in the superficial layers of prelimbic and infralimbic cortex. It decreased the number of PNNs in the prelimbic of wildtype animals but not in the DISC1-KO cohort. MK-801 moderately increased PV counts in DISC1-KO.
CONCLUSIONS: This DISC1-KO model is a promising model of schizophrenia as we see the same directionality of decreases in PV and PNN as post mortem human studies. Furthermore, MK-801 is seen to have an increasing trend effect on PV cells, which should be considered when interpreting findings in future studies that look at these markers
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To Define the Mechanistic Basis for the Effect of RECK Alternative Isoform Expression on Cell Migration
Get PDFFor many types of animal cells, migration is essential for their physiological function. Long distance crawling is required for the development of a nervous system and for the ability of macrophages to accumulate at sites of infection. In response to a wound, resident fibroblasts migrate to the wound site and promote the wound healing process. Furthermore, cancer metastasis involves the ability of cancer cells to transform their morphology and acquire an ability to migrate. A better understanding of cell migration would have implications for normal development and could yield therapies for multiple different disease states, including fibrosis, atherosclerosis, and metastasis. Alternative polyadenylation (APA) is the process by which the same genetic locus can produce multiple transcripts ending at different polyadenylation sites. Coding sequence APA can change the length of the amino acid and can also switch the function of the protein. Proliferating cells, cancer cells, and stem cells in the early stages of mouse development and tumors tend to use proximal polyadenylation sites and commonly show rapid cell migration. Our laboratory has discovered that fibroblast migration can be regulated through polyadenylation site selection. To date, however, no studies have been performed to research how cell migration and invasion can be controlled by APA.Reversion-inducing-cysteine-rich protein with kazal-like motifs (RECK) suppresses cell migration. Previous studies have documented a role for RECK on the cell surface in inhibiting MMP activity via its Kazal-like motifs. RECK has also been implicated in tubulin dynamics and in anterior-posterior polarity. Our lab discovered through an RNA-Seq-based screen that there are short and long RECK isoforms that are generated by coding region alternative polyadenylation. In this dissertation, I explain how cell migration and invasion can be controlled by APA via alternative isoform expression of the RECK protein. I show that the short RECK isoform promotes cell migration and that this result is mediated by short RECK and long (canonical) RECK interaction. Furthermore, I propose that RECK APA can regulate cell migration not only through its established role of modifying matrix metalloproteinases but also via its roles in affecting tubulin post-translational modifications (PTMs). These studies provide a much more detailed and mechanistic model for the biological functions of RECK alternative isoform use
신속 감염병 진단을 위한 나노공학 기반 유전자 검출법 연구
No full textFor diagnosing infections, a simple and facile assay which can be directly visualized with minimal technical requirements is in great need. Nucleic acid analytes is one of the most widely used for identification of molecular targets as biomarker in biomedical research. A rapid and simple detection method for nucleic acid anlaytes allows rapid diagnosis of disease and subsequent treatment. Nucleic acid amplification techniques are used for molecular biology research and medical diagnostics to specifically detect and analyze small amounts of genetic targets. Especially, the improved detectable signal can be achieved through integrated with nanotechnology. This paper is organized as follows.
In Chapter 2, we introduce a fluorescent nanosensor utilizing carbon dot nanoparticles that form visible precipitates in the presence of target DNA. Carbon dot nanoparticles were fabricated by microwave pyrolysis of polyethylenimine, which emitted strong photoluminescence and could form precipitates when added with target DNA oligonucleotides. The precipitates could be easily visualized by UV illumination, and data could be acquired as images using a smart phone which were analyzed for quantification. This carbon dot-based assay allowed fluorescent sensing of target oligonucleotides with various sizes, and visualization even with minimal amount of DNA (~100 pmol). Finally, the assay could be applied as a nanosensor platform for detecting bacterial DNA for the antibiotic resistance gene KPC-2 from Klebsiella pneumoniae. This method provides a simple technique for detecting molecular targets, showing wide applicability for diagnostics on the bedside or point-of-care testing.
In Chapter 3, we propose a simple paper-based fluorescent sensor for the detection of SARS-CoV-2 using isothermal amplification method, RCA. The fluorescent particles of solution on the filter paper are radially transferred to generate the fluorescent ring patterns by capillary phenomenon. During the RCA amplification process, a micron-sized ssDNA was produced in which a certain sequence is repeated, and this DNA was labeled through hybridization with probe-dye, which has the complementary sequence of RCA products, allowing to be concentrated fluorescent signal in the central droplets on the filter paper. The target can be detected simply by fluorescent ring pattern formed under a UV lamp after the droplet is completely spread within a few minutes. Furthermore, the assay is possible to detect the multiple targets by designed the different padlock templates and probe-dyes with various emission wavelengths. The assay can be a useful and easily applicable diagnostic tool for point-of-care detection of various infectious diseases such as COVID-19, bacterial infections.
We expect that the diagnostic platform, which is simple, easy-to-use compared to the existing technologies, developed in this study is possible to advance for self-diagnosis in the future through low-cost analysis equipment, allowing to change the place of diagnosis from hospital to home.한국과학기술원 :나노과학기술대학원,학위논문(박사) - 한국과학기술원 : 나노과학기술대학원, 2021.8,[vii, 47 p. :
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Etiological Classification and Developmental Outcomes in Floppy Infants: A Single Tertiary Center Experience
Get PDFPurpose: Floppy infants or congenital hypotonia indicates decreased muscle tone in infants secondary to abnormalities of the central or the peripheral nervous system, or both. Previous literature classified its causes as those attributable to a central vs. peripheral origin; however, recent studies have introduced a newer classification describing a combined origin. We invenstigated floppy infants by applying the new etiological classification and reviewed the most common etiologies based on the age of presentation. We additionally reviewed the clinical characteristics, diagnoses, and the developmental outcomes in these infants. Methods: We retrospectively reviewed the electronic medical charts and recruited 116 infants diagnosed with floppy infant syndrome between January 2005 and December 2016 at Severance Children’s Hospital. Among these infants, 66 with a confirmed diagnosis were reviewed for the etiological classification. Information regarding developmental outcomes was obtained via phone interviews with the infants’ families. Results: Based on the new etiological classification, among 69 infants with a confirmed diagnosis, in 40 (34.5%) this syndrome was of central origin, in 19 (16.4%) of peripheral origin, and in 10 (8.6%) of combined origin. Prader-Willi syndrome, myotonic dystrophy, and spinal muscular atrophy were the most common disorders observed and combined hypotonia showed the poorest developmental outcome. Conclusion: The study states the importance of proper evaluation of etiological diagnosis and optimal intervention for developmental prognosis. The introduction of a new etiological group of combined hypotonia especially emphasizes regular monitoring and timely rehabilitative intervention in patients for the better quality of life in them as well as their caregivers.ope
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