Diagnostics

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Non-Invasive Screening Tools for Down’s Syndrome: A Review

by Kelly A. Sillence, Tracey E. Madgett, Llinos A. Roberts, Timothy G. Overton and Neil D. Avent

Diagnostics 2013, 3(2), 291-314; https://doi.org/10.3390/diagnostics3020291 - 31 May 2013

Cited by 10 | Viewed by 13378

Down’s syndrome (DS) is the most common genetic cause of developmental delay with an incidence of 1 in 800 live births, and is the predominant reason why women choose to undergo invasive prenatal diagnosis. However, as invasive tests are associated with around a [...] Read more.

Down’s syndrome (DS) is the most common genetic cause of developmental delay with an incidence of 1 in 800 live births, and is the predominant reason why women choose to undergo invasive prenatal diagnosis. However, as invasive tests are associated with around a 1% risk of miscarriage new non-invasive tests have been long sought after. Recently, the most promising approach for non-invasive prenatal diagnosis (NIPD) has been provided by the introduction of next generation sequencing (NGS) technologies. The clinical application of NIPD for DS detection is not yet applicable, as large scale validation studies in low-risk pregnancies need to be completed. Currently, prenatal screening is still the first line test for the detection of fetal aneuploidy. Screening cannot diagnose DS, but developing a more advanced screening program can help to improve detection rates, and therefore reduce the number of women offered invasive tests. This article describes how the prenatal screening program has developed since the introduction of maternal age as the original “screening” test, and subsequently discusses recent advances in detecting new screening markers with reference to both proteomic and bioinformatic techniques. Full article

(This article belongs to the Special Issue Advance in Prenatal Diagnosis)

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Open AccessArticle

Overview of Five-Years of Experience Performing Non-Invasive Fetal Sex Assessment in Maternal Blood

by Sara Perlado-Marina, Ana Bustamante-Aragones, Laura Horcajada, Maria Jose Trujillo-Tiebas, Isabel Lorda-Sanchez, Marta Ruiz Ramos, Javier Plaza and Marta Rodriguez de Alba

Diagnostics 2013, 3(2), 283-290; https://doi.org/10.3390/diagnostics3020283 - 15 May 2013

Cited by 8 | Viewed by 6654

Abstract

Since the discovery of the presence of fetal DNA in maternal blood, non-invasive fetal sex determination has been the test most widely translated into clinical practice. To date there is no agreement between the different laboratories performing such tests in relation to which [...] Read more.

Since the discovery of the presence of fetal DNA in maternal blood, non-invasive fetal sex determination has been the test most widely translated into clinical practice. To date there is no agreement between the different laboratories performing such tests in relation to which is the best protocol. As a consequence there are almost as many protocols as laboratories offering the service, using different methodologies and thus obtaining different diagnostic accuracies. By the end of 2007, after a validation study performed in 316 maternal samples collected between the 5th and 12th week of gestation, the fetal sex determination was incorporated into clinical practice in our Service. The test is performed in the first trimester of pregnancy, and it is offered as part of the genetic counseling process for couples at risk of X-linked disorders. As a general rule and in order to avoid misdiagnosis, two samples at different gestational ages are tested per patient. The analysis is performed by the study of the SRY gene by RT-PCR. Two hundred and twenty six pregnancies have been tested so far in these 5 years. Neither false positives nor false negatives diagnoses have been registered, thus giving a diagnostic accuracy of 100%. Full article

(This article belongs to the Special Issue Advance in Prenatal Diagnosis)

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Open AccessArticle

Quantification of Right and Left Ventricular Function in Cardiac MR Imaging: Comparison of Semiautomatic and Manual Segmentation Algorithms

by Miguel Souto, Lambert Raul Masip, Miguel Couto, Jorge Juan Suárez-Cuenca, Amparo Martínez, Pablo G. Tahoces, Jose Martin Carreira and Pierre Croisille

Diagnostics 2013, 3(2), 271-282; https://doi.org/10.3390/diagnostics3020271 - 03 Apr 2013

Cited by 11 | Viewed by 7913

Abstract

The purpose of this study was to evaluate the performance of a semiautomatic segmentation method for the anatomical and functional assessment of both ventricles from cardiac cine magnetic resonance (MR) examinations, reducing user interaction to a “mouse-click”. Fifty-two patients with cardiovascular diseases were [...] Read more.

The purpose of this study was to evaluate the performance of a semiautomatic segmentation method for the anatomical and functional assessment of both ventricles from cardiac cine magnetic resonance (MR) examinations, reducing user interaction to a “mouse-click”. Fifty-two patients with cardiovascular diseases were examined using a 1.5-T MR imaging unit. Several parameters of both ventricles, such as end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF), were quantified by an experienced operator using the conventional method based on manually-defined contours, as the standard of reference; and a novel semiautomatic segmentation method based on edge detection, iterative thresholding and region growing techniques, for evaluation purposes. No statistically significant differences were found between the two measurement values obtained for each parameter (p > 0.05). Correlation to estimate right ventricular function was good (r > 0.8) and turned out to be excellent (r > 0.9) for the left ventricle (LV). Bland-Altman plots revealed acceptable limits of agreement between the two methods (95%). Our study findings indicate that the proposed technique allows a fast and accurate assessment of both ventricles. However, further improvements are needed to equal results achieved for the right ventricle (RV) using the conventional methodology. Full article

(This article belongs to the Special Issue Advance in Molecular Diagnostics and Imaging)

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Open AccessArticle

Computed Tomography (CT) Perfusion in Abdominal Cancer: Technical Aspects

by Martin Lundsgaard Hansen, Rikke Norling, Carsten Lauridsen, Eva Fallentin, Lene Bæksgaard, Klaus Fuglsang Kofoed, Lars Bo Svendsen and Michael Bachmann Nielsen

Diagnostics 2013, 3(2), 261-270; https://doi.org/10.3390/diagnostics3020261 - 03 Apr 2013

Cited by 11 | Viewed by 8945

Abstract

Computed Tomography (CT) Perfusion is an evolving method to visualize perfusion in organs and tissue. With the introduction of multidetector CT scanners, it is now possible to cover up to 16 cm in one rotation, and thereby making it possible to scan entire [...] Read more.

Computed Tomography (CT) Perfusion is an evolving method to visualize perfusion in organs and tissue. With the introduction of multidetector CT scanners, it is now possible to cover up to 16 cm in one rotation, and thereby making it possible to scan entire organs such as the liver with a fixed table position. Advances in reconstruction algorithms make it possible to reduce the radiation dose for each examination to acceptable levels. Regarding abdominal imaging, CT perfusion is still considered a research tool, but several studies have proven it as a reliable non-invasive technique for assessment of vascularity. CT perfusion has also been used for tumor characterization, staging of disease, response evaluation of newer drugs targeted towards angiogenesis and as a method for early detection of recurrence after radiation and embolization. There are several software solutions available on the market today based on different perfusion algorithms. However, there is no consensus on which protocol and algorithm to use for specific organs. In this article, the authors give an introduction to CT perfusion in abdominal imaging introducing technical aspects for calculation of perfusion parameters, and considerations on patient preparation. This article also contains clinical cases to illustrate the use of CT perfusion in abdominal imaging. Full article

(This article belongs to the Collection Feature Papers)

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Open AccessArticle

A Rapid, Multiplexed, High-Throughput Flow-Through Membrane Immunoassay: A Convenient Alternative to ELISA

by Sujatha Ramachandran, Mitra Singhal, Katherine G. McKenzie, Jennifer L. Osborn, Amit Arjyal, Sabina Dongol, Stephen G. Baker, Buddha Basnyat, Jeremy Farrar, Christiane Dolecek, Gonzalo J. Domingo, Paul Yager and Barry Lutz

Diagnostics 2013, 3(2), 244-260; https://doi.org/10.3390/diagnostics3020244 - 02 Apr 2013

Cited by 28 | Viewed by 13512

Abstract

This paper describes a rapid, high-throughput flow-through membrane immunoassay (FMIA) platform. A nitrocellulose membrane was spotted in an array format with multiple capture and control reagents for each sample detection area, and assay steps were carried out by sequential aspiration of sample and [...] Read more.

This paper describes a rapid, high-throughput flow-through membrane immunoassay (FMIA) platform. A nitrocellulose membrane was spotted in an array format with multiple capture and control reagents for each sample detection area, and assay steps were carried out by sequential aspiration of sample and reagents through each detection area using a 96-well vacuum manifold. The FMIA provides an alternate assay format with several advantages over ELISA. The high surface area of the membrane permits high label concentration using gold labels, and the small pores and vacuum control provide rapid diffusion to reduce total assay time to ~30 min. All reagents used in the FMIA are compatible with dry storage without refrigeration. The results appear as colored spots on the membrane that can be quantified using a flatbed scanner. We demonstrate the platform for detection of IgM specific to lipopolysaccharides (LPS) derived from Salmonella Typhi. The FMIA format provides analytical results comparable to ELISA in less time, provides integrated assay controls, and allows compensation for specimen-to-specimen variability in background, which is a particular challenge for IgM assays. Full article

(This article belongs to the Collection Feature Papers)

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Open AccessReview

Can Coronary Artery Involvement in Kawasaki Disease be Predicted?

by Sunil J. Ghelani, Neha S. Kwatra and Christopher F. Spurney

Diagnostics 2013, 3(2), 232-243; https://doi.org/10.3390/diagnostics3020232 - 26 Mar 2013

Cited by 8 | Viewed by 5770

Abstract

Background: Coronary artery involvement is seen in approximately 15–20% of children with Kawasaki disease. There is conflicting literature regarding the clinical and laboratory findings associated with coronary artery involvement. In this retrospective study, we attempt identification of predictive factors for coronary artery [...] Read more.

Background: Coronary artery involvement is seen in approximately 15–20% of children with Kawasaki disease. There is conflicting literature regarding the clinical and laboratory findings associated with coronary artery involvement. In this retrospective study, we attempt identification of predictive factors for coronary artery involvement at our institute and review the existing literature. Methods and results: A review of 203 patients (65% males) with Kawasaki disease was performed, of whom 33 (16.3%) had coronary artery involvement. High erythrocyte sedimentation rate, high platelet count, low hematocrit, low albumin levels, and refractory Kawasaki disease showed significant association with coronary artery involvement. High erythrocyte sedimentation rate and refractory Kawasaki disease were found to be independent predictors of coronary artery involvement. Review of literature suggested a wide range of coronary involvement (<5% to >60%), and highly conflicting clinical and laboratory associations. Conclusion: It remains difficult to accurately determine risk of coronary artery involvement, although some laboratory markers may provide information that is helpful for parental counseling and clinical follow up. Future identification of novel biomarkers and host predispositions may further our understanding of coronary artery risks and help personalize therapy for Kawasaki disease. Full article

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Open AccessArticle

Diagnosis of Upper and Lower Respiratory Tract Bacterial Infections with the Use of Multiplex PCR Assays

by Athanasia Xirogianni, Maria Tsolia, Aliki Voyiatzi, Maria Sioumala, Antonia Makri, Athina Argyropoulou, Olga Paniara, Panayotis Markoulatos, Jenny Kourea-Kremastinou and Georgina Tzanakaki

Diagnostics 2013, 3(2), 222-231; https://doi.org/10.3390/diagnostics3020222 - 26 Mar 2013

Cited by 9 | Viewed by 7701

Abstract

The investigation of respiratory infections by molecular techniques provides important information about the epidemiology of respiratory disease, especially during the post-vaccination era. The objective of the present study was the detection of bacterial pathogens directly in clinical samples from patients with upper and [...] Read more.

The investigation of respiratory infections by molecular techniques provides important information about the epidemiology of respiratory disease, especially during the post-vaccination era. The objective of the present study was the detection of bacterial pathogens directly in clinical samples from patients with upper and lower respiratory tract infections using multiplex polymerase chain reaction (PCR) assays developed in our laboratory. Clinical samples taken over a three-year period (2007–2009) and obtained from 349 patients (adults (n = 66); children (n = 283)) with signs and symptoms of certain upper or lower respiratory tract infections, consisted of: bronchoalveolar lavages (BAL, n = 83), pleural fluids (n = 29), and middle-ear aspirates (n = 237). Overall, 212 samples (61%) were confirmed by culture and/or PCR. Among the positive samples, Streptococcus pneumoniae (mainly serotype 3) was predominant (104/212; 49.0%), followed by non-typable Haemophilus influenzae (NTHi) 59/212; 27.8%) and Streptococcus pyogenes (47/212; 22%). Haemophilus influenzae type b was detected in only three samples. The underlying microbiology of respiratory infections is gradually changing in response to various selective pressures, such as vaccine use and antibiotic consumption. The application of multiplex PCR (mPCR) assays is particularly useful since it successfully identified the microorganisms implicated in acute otitis media or lower respiratory tract infections in nearly 75% of patients with a positive result compared to conventional cultures. Non-culture identification of the implicated pneumococcal serotypes is also an important issue for monitoring pneumococcal infections in the era of conjugate pneumococcal vaccines. Full article

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Open AccessReview

Catecholamines and Neurodegeneration in Parkinson’s Disease—From Diagnostic Marker to Aggregations of α-Synuclein

by Hideyuki Sawada, Tomoko Oeda and Kenji Yamamoto

Diagnostics 2013, 3(2), 210-221; https://doi.org/10.3390/diagnostics3020210 - 25 Mar 2013

Cited by 7 | Viewed by 8155

Abstract

Parkinson’s disease is the second most prevalent disease of the brain. It is characterized by midbrain dopaminergic neuronal degeneration accompanied by Lewy bodies, intra-cytoplasmic neuronal inclusions that consist mainly of alpha-synuclein. The cardinal motor features are muscular rigidity, bradykinesia, and resting tremor and, [...] Read more.

Parkinson’s disease is the second most prevalent disease of the brain. It is characterized by midbrain dopaminergic neuronal degeneration accompanied by Lewy bodies, intra-cytoplasmic neuronal inclusions that consist mainly of alpha-synuclein. The cardinal motor features are muscular rigidity, bradykinesia, and resting tremor and, in advanced cases, postural instability. Symptoms are relieved by dopamine replacement therapy, but progress slowly. Clinical diagnosis is made according to medical history, neurological examinations and the response to anti-Parkinsonian drugs. There are no laboratory tests for diagnosis of the disease; however, for development of disease-modifying treatment, early diagnosis by objective laboratory test is required. Recently, postsynaptic sympathetic norepinephrine nerve terminals were found to be degenerated as well as mesencephalic dopaminergic neurons. Cardiac norepinephrine denervation can be seen by meta-iodine-benzyl guanidine scintigraphy, and may be a reliable diagnostic marker. Degeneration of norepinephrinergic and dopaminergic neurons suggests that catecholamines may play a central role in the neurodegeneration in Parkinson’s disease. Recently several studies showed that alpha-synuclein aggregates in cells exposed to dopamine. Here, we review findings relating to an early diagnostic marker for detecting degeneration of the peripheral sympathetic nerves, and propose the hypothesis that catecholamines cause alpha-synuclein to aggregate and play an important role in disease pathogenesis. Full article

(This article belongs to the Collection Feature Papers)

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Diagnostics, Volume 3, Issue 2 (June 2013) – 8 articles , Pages 210-314

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