96 research outputs found
Evaluation of PCR in the diagnosis of tuberculosis
No full textTuberculosis (TB) continues to be a major health problem worldwide. Early diagnosis and prompt initiation of treatment, play important role in interrupting transmission of tubercle bacilli and in improving disease outcome. Isolation and identification of M. tuberculosis by conventional methods is problematic and requires 4 to 8 weeks. Recently, significant progress has been made in diagnosing tuberculosis by molecular biologic techniques. The aim of the present study was to evaluate the sensitivity and specificity of Polymerase Chain Reaction (PCR), in the diagnosis of different forms of tuberculosis.A total of 3180 clinical specimens; 472 sputum, 193 bronchoalveolar lavage (BAL), 851 cerebrospinal fluid, 765 gastric fluid, 512 pleural fluid, 74 pericardial fluid, 104 abscess fluid, 189 urine, and 20 bone biopsies were collected prospectively and examined by PCR (Amplicor MTB), cultures on Lowenstein-Jensen agar and for presence of acid fast bacilli on direct smears. Clinical data for each patient had been collected on a standardized form. Patients were divided in three categories: Definite cases of tuberculosis were considered those with positive culture for M. tuberculosis, probable cases those with negative culture, but clinical features, laboratory, and radiographic findings compatible with TB, and the remaining patients without any clinical or laboratory evidence for TB were regarded to have no tuberculosis.M. tuberculosis DNA was detected in 32 of 34 bactreriologically confirmed (sensitivity 94,1%) and in 8 of 10 probable cases of pulmonary tuberculosis (sensitivity 80%), whereas only 12 of 631 with no tuberculosis yielded a PCR product corresponding to M. tuberculosis (specificity 98,1%). M. tuberculosis DNA was detected in 39 of 44 bactreriologically confirmed (sensitivity 88,6%) and in 14 of 17 probable cases of tuberculous meningitis (sensitivity 82,4%), whereas only 23 of 807 CSF samples from patients with no tuberculosis yielded a PCR product (specificity 98,1%). None of the CSF samples from patients with meningitis of known etiologies other than tuberculous (microbial,viral, etc., n= 'fx) yielded a positive result by PCR. In gastric aspirate specimens, M. tuberculosis DNA was detected in 27 of 29 bactreriologically confirmed (sensitivity 93,1%) and in 8 of 11 probable cases of tuberculosis (sensitivity 72,8%), whereas only 12 of 736 gastric aspirates from patients with no tuberculosis yielded a PCR product (specificity 98,4%). In the remaining specimens (pleural fluid, pericardial fluid, abscess fluid, urine, osseous biopsy specimen) M. tuberculosis DNA was detected in 36 of 52 bactreriologically confirmed (sensitivity 69,2%) and in 14 of 18 probable cases of tuberculosis (sensitivity 77,8%), whereas only 40 of 847 with no tuberculosis yielded a PCR product corresponding to M. tuberculosis (specificity 95,2%). The sensitivity of PCR was higher in smear positive than in smear negative samples. PCR results were available within 6,5 hours at a reasonable cost (70 € per sample).The findings support that Amplicor PCR MTB is a useful test with high sensitivity and specificity for rapid diagnosis of different forms of tuberculosis.Η φυματίωση εξακολουθεί να αποτελεί σοβαρό πρόβλημα υγείας παγκοσμίως. Η έγκαιρη διάγνωση και αντιμετώπιση της νόσου, είναι σημαντικά για τη μείωση της μετάδοσης του μυκοβακτηριδίου και τηΥκαλή έκβαση της νόσου. Οι συμβατικές μέθοδοι απομόνωσης και ταυτοποίησης του Μ, tuberculosis παρουσιάζουν μειονεκτήματα, όπως χαμηλή ευαισθησία ή απαιτούν 4-8 εβδομάδες για την ολοκλήρωσή τους. Τα τελευταία χρόνια, έχει γίνει σημαντική πρόοδος στη διάγνωση της φυματίωσης με τη χρήση μοριακών τεχνικών. Σκοπός της παρούσας μελέτης ήταν, η εφαρμογή και αξιολόγηση της μεθόδου PCR για τη έγκαιρη διάγνωση διαφόρων κλινικών μορφών φυματίωσης.Συλλέχθηκαν 3457 δείγματα βιολογικών υλικών από ασθενείς με κλινική υποψία φυματίωσης και αξιολογήθηκαν 3180: 472 πτύελα, 193 βρογχοκυψελιδικό έκπλυμα (BAL), 851 εγκεφαλονωτιαίο υγρό, 765 γαστρικό υγρό, 512 πλευριτικό υγρό, 74 περικαρδιακό υγρό, 104 πύο, 189 ούρα, 20 οστικό υλικό τα οποία εξετάστηκαν με PCR (Amplicor PCR MTB), χρώση για οξεάντοχα βακτήρια (Ziehl-Neelsen) και καλλιέργεια σε Lowenstein- Jensen. Επίσης, καταγράφηκαν κλινικά στοιχεία για τους ασθενείς από τους οποίους προέρχονταν τα δείγματα. Επιβεβαιωμένες περιπτώσεις φυματίωσης θεωρήθηκαν εκείνες που είχαν θετική καλλιέργεια για Μ.tuberculosis, πιθανές περιπτώσεις εκείνες με αρνητική καλλιέργεια, αλλά κλινική εικόνα, ακτινολογικά ευρήματα και λοιπό εργαστηριακό έλεγχο συμβατά με τη νόσο, Mantoux θετική, και ανταπόκριση στην αντιφυματική αγωγή, ενώ ότι δεν έπασχαν από φυματίωση οι ασθενείς, όταν η καλλιέργεια για Μ. tuberculosis ήταν αρνητική και δεν παρουσίαζαν κλινικά και εργαστηριακά ευρήματα συμβατά με τη νόσο.Στα δείγματα πτυέλων και BAL, η PCR ανίχνευσε Μ. tuberculosis DNA σε 32 από τις 34 (ευαισθησία 94,1%) επιβεβαιωμένες περιπτώσεις και σε 8 από τις 10 (ευαισθησία 80%) πιθανές περιπτώσεις πνευμονικής φυματίωσης, ενώ η PCR ήταν θετική σε 12 από 631 (ειδικότητα-" 98,1%) δείγματα από ασθενείς χωρίς επιβεβαιωμένη φυματίωση. Στα δείγματα ΕΝΥ, η PCR ήταν θετική σε 39 από τις 44 (ευαισθησία 88,6%) επιβεβαιωμένες περιπτώσεις και σε 14 από τις 17 (ευαισθησία 82,4%) πιθανές περιπτώσεις φυματιώδους μηνιγγίτιδας, ενώ η PCR ήταν θετική σε 23 από 807 (ειδικότητα 98,1%) δείγματα από ασθενείς χωρίς φυματίωση. Η PCR ήταν αρνητική σε όλα τα δείγματα ΕΝΥ (π=9%) από ασθενείς με μηνιγγίτιδα γνωστής αιτιολογίας εκτός φυματιώδους (μικροβιακή, ιογενή κ.τ.λ.,). Σε δείγματα από γαστρικό υγρό, η PCR ανίχνευσε μυκοβακτηριδιακό DNA σε 27 από 29 (ευαισθησία 93,1%) ασθενείς με επιβεβαιωμένη και σε 8 από 11 (ευαισθησία 72,8%), ασθενείς με πιθανή φυματίωση, ενώ η PCR ήταν θετική σε 12 από 736 (ειδικότητα 98,4%) δείγματα από ασθενείς χωρίς επιβεβαιωμένη φυματίωση. Από τα υπόλοιπα δείγματα (πλευριτικό υγρό, περικαρδιακό υγρό, πύο, ούρα, οστικό υλικό) Μ. tuberculosis DNA ανιχνεύθηκε σε 36 από 52 (ευαισθησία 69,2%) επιβεβαιωμένες και σε 14 από 18 (ευαισθησία 77,8%), πιθανές περιπτώσεις φυματίωσης, ενώ η PCR ήταν θετική σε 40 από 847 (ειδικότητα 95,2%) ασθενείς χωρίς επιβεβαιωμένη φυματίωση. Η ευαισθησία της PCR ήταν υψηλότερη στα δείγματα με θετική άμεση χρώση για οξεάντοχα βακτήρια. Η ολοκλήρωση της PCR απαιτεί 6.5 ώρες και το κόστος ανά δείγμα περίπου 70 €.Τα ευρήματα μας υποστηρίζουν ότι η PCR- Amplicor MTB αποτελεί αξιόπιστη μέθοδο, με υψηλή ευαισθησία και ειδικότητα, για την ταχεία διάγνωση διαφόρων μορφών φυματίωσης
Advances in Biotechnology and the Development of Novel Human Vaccines
No full textRecent advances in biotechnology have fundamentally reshaped the landscape of vaccine development, offering innovative strategies to improve immunogenicity, safety and accessibility. This review explores the cutting-edge platforms—including mRNA, DNA, virus-like particles, viral and bacterial vectors, and bacteriophage-based vaccines—that are redefining how vaccine antigens are delivered to the immune system. We also discuss alternative delivery methods, such as transcutaneous and mucosal immunization, which have the potential to improve vaccine acceptance and distribution, as well as next-generation adjuvants targeting innate immune receptors aiming to further enhance vaccine efficacy, especially in vulnerable populations. By synthesizing these innovations, this review highlights how biotechnology is enabling the design of safer, more efficient, and more adaptable vaccines to address both existing and emerging infectious diseases
A Novel Concurrent Validation Scheme for Hardware Transactional Memory
No full textTransactional memory is a lock-free parallel programming model, which aims at replacing conventional lock-based threaded programming techniques, currently used by multi-core systems. These techniques are difficult to implement and impose unnecessary overheads caused by conservative programming practices. In this thesis, the scalability potential of a transactional memory system, called TMFab, was explored for different numbers of processors and it was concluded that for more than 4 processors the system presents reduced scalability, due to an increase in the validation overhead. In response to this observation, a novel validation scheme was proposed which reduces this overhead, first by allowing multiple transactions to perform their validations and commit operations concurrently, and second by removing the need for broadcasting messages between the active transactions. A distributed shared memory scheme was used to increase the validation and memory access throughput, as well as allow for transactions to commit concurrently on different memory partitions. The two architectures were compared by means of SystemC simulation, and a maximum of 2.5x validation speedup was observed for the modified design, together with a 2.7x reduction in memory access latency. In total, the modified design achieved a maximum execution speedup of 30% over the original, for the benchmarks that were used. Furthermore, the modified system guarantees sequential consistency even in corner case scenarios.Computer EngineeringCircuits and SystemsElectrical Engineering, Mathematics and Computer Scienc
SARS-CoV-2 variants and effectiveness of vaccines: a review of current evidence
No full textThe SARS-CoV-2 virus is rapidly evolving via mutagenesis, lengthening the pandemic, and threatening the public health. Until August 2021, 12 variants of SARS-CoV-2 named as variants of concern (VOC; Alpha to Delta) or variants of interest (VOI; Epsilon to Mu), with significant impact on transmissibility, morbidity, possible reinfection and mortality, have been identified. The VOC Delta (B.1.617.2) of Indian origin is now the dominant and the most contagious variant worldwide as it provokes a strong binding to the human ACE2 receptor, increases transmissibility and manifests considerable immune escape strategies after natural infection or vaccination. Although the development and administration of SARS-CoV-2 vaccines, based on different technologies (mRNA, adenovirus carrier, recombinant protein, etc.), are very promising for the control of the pandemic, their effectiveness and neutralizing activity against VOCs varies significantly. In this review, we describe the most significant circulating variants of SARS-CoV-2, and the known effectiveness of currently available vaccines against them
Effect of prophylactic administration of antipyretics on the immune response to pneumococcal conjugate vaccines in children: a systematic review
No full textBackground Prophylactic administration of antipyretics at the time of immunization seems to decrease some side effects, however reduced immune responses have been reported in some studies. This systematic review aimed to investigate the effect of prophylactic use of antipyretics on the immune response following administration of pneumococcal conjugate vaccines (PCVs). Methods A systematic review of randomized controlled trials and observational studies concerning the immune response to PCVs after antipyretic administration was performed up to November 2020 in the electronic databases of Pubmed and Scopus. Results Of the 3956 citations retrieved, a total of 5 randomized control trials including 2775 children were included in the review. Included studies were referred to PCV10 (3 studies), PCV7 and PCV13 (one study each). The prophylactic administration of paracetamol decreased the immune response to certain pneumococcal serotypes in all included studies. The effect was more evident following primary vaccination and with immediate administration of paracetamol. Despite the reductions in antibody geometric mean concentrations, a robust memory response was observed following the booster dose. Besides, antibody titers remained above protective levels in 88-100% of participants. The use of ibuprofen, that was evaluated in two studies, did not seem to affect the immunogenicity of PCVs . Conclusion Although the reviewed studies had significant heterogeneity in design, paracetamol administration seems to affect the immune response for certain serotypes. The clinical significance of reduced immunogenicity especially before booster dose needs further investigation
The impact of probiotics' administration on glycemic control, body composition, gut microbiome, mitochondria, and other hormonal signals in adolescents with prediabetes – A randomized, controlled trial study protocol
No full textImmunology of Multisystem Inflammatory Syndrome after COVID-19 in Children: A Review of the Current Evidence
No full textImmune responses following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in children are still under investigation. Even though coronavirus disease 2019 (COVID-19) is usually mild in the pediatric population, some children exhibit severe clinical manifestations, require hospitalization, or develop the most severe condition: a multisystem inflammatory syndrome in children (MIS-C) associated with SARS-CoV-2 infection. The activated innate, humoral and T-cell-mediated immunological pathways that lead certain pediatric populations to present with MIS-C or remain asymptomatic after SARS-CoV-2 infection are yet to be established. This review focuses on the immunological aspects of MIS-C with respect to innate, humoral, and cellular immunity. In addition, presents the role of the SARS-CoV-2 Spike protein as a superantigen in the pathophysiological mechanisms, discusses the great heterogeneity among the immunological studies in the pediatric population, and highlights possible reasons why some children with a certain genetic background present with MIS-C
The impact of probiotics' administration on glycemic control, body composition, gut microbiome, mitochondria, and other hormonal signals in adolescents with prediabetes – A randomized, controlled trial study protocol
No full textBackground: Recent studies have demonstrated that a significant proportion of adolescents exhibit abdominal obesity in early–middle adolescence, and impaired glucose metabolism. Dysregulation of glucose metabolism is aggravated by the existing osteosarcopenia not only in obese but also in overweight youth. Biochemical inflammation, derived from glucose metabolism dysregulation, in combination with increased stress levels lead to the accumulation of reactive oxygen species, also known as ROS, which seem to afflict the integrity of the gastrointestinal wall, gut mucosa, and commensal, intestinal gut microflora. The current scientific protocol aims to assess the administration of probiotics in prediabetic adolescents in relation with their glycemic control, body composition, and intestinal microbiome. Methods/Design: This is a study protocol of a two-armed RCT, that recruits adolescents with prediabetes, who will receive either a 4-month, life-style intervention, or a life-style intervention along with a probiotic supplement. The primary outcome is the differences in gut microbiome synthesis, body composition analysis parameters, and concentrations of hormones, before and after the intervention. Discussion: This study aims to halt the progression of obesity and diabetes and aspires to contribute new evidence for upgraded treatment of obesity and diabetes. Trial registration: Australian New Zealand Clinical Trial Registry (ACTRN12615000470594). Keywords: Gut microbiome, Prediabetes, Probiotics, Gut barrier, RCT, Mitochondrio
Immune response to SARS-CoV-2 in children: A review of the current knowledge
No full textHost immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), especially in children, are still under investigation. Children with coronavirus disease 2019 (COVID-19) constitute a significant study group of immune responses as they rarely present with severe clinical manifestations, require hospitalization, or develop complications such as multisystem inflammatory syndrome in children (MIS-C) associated with SARS-CoV-2 infection. The deciphering of children's immune responses during COVID-19 infection will provide information about the protective mechanisms, while new potential targets for future therapies are likely to be revealed. Despite the limited immunological studies in children with COVID-19, this review compares data between adults and children in terms of innate and adaptive immunity to SARS-CoV-2, discusses the possible reasons why children are mostly asymptomatic, and highlights unanswered or unclear immunological issues. Current evidence suggests that the activity of innate immunity seems to be crucial to the early phases of SARS-CoV-2 infection and adaptive memory immunity is vital to prevent reinfection
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