RESUMEN
OBJECTIVES: Contamination with intravenous (IV) fluids is a common cause of specimen rejection or erroneous results in hospitalized patients. Identification of contaminated samples can be difficult. Common measures such as failed delta checks may not be adequately sensitive nor specific. This study aimed to determine detection criteria using commonly ordered tests to identify IV fluid contamination and validate the use of these criteria. METHODS: Confirmed contaminated and non-contaminated samples were used to identify patterns in laboratory results to develop criteria to detect IV fluid contamination. The proposed criteria were implemented at a tertiary care hospital laboratory to assess performance prospectively for 6 months, and applied to retrospective chemistry results from 3 hospitals and 1 community lab to determine feasibility and flagging rates. The algorithm was also tested at an external institution for transferability. RESULTS: The proposed algorithm had a positive predictive value of 92 %, negative predictive value of 91 % and overall agreement of 92 % when two or more criteria are met (n = 214). The flagging rates were 0.03 % to 0.07 % for hospital and 0.003 % for community laboratories. CONCLUSIONS: The proposed algorithm identified true contamination with low false flagging rates in tertiary care urban hospital laboratories. Retrospective and prospective analysis suggest the algorithm is suitable for implementation in clinical laboratories to identify samples with possible IV fluid contamination for further investigation.
Asunto(s)
Algoritmos , Humanos , Estudios Retrospectivos , Laboratorios Clínicos , Estudios Prospectivos , Manejo de Especímenes/métodos , Manejo de Especímenes/normasRESUMEN
Frequent screening of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among asymptomatic populations using antigen-based point-of-care tests (APOCTs) is occurring globally with limited clinical performance data. The positive predictive value (PPV) of two APOCTs used in the asymptomatic screening of SARS-CoV-2 among health care workers (HCWs) at continuing care (CC) sites across AB, Canada, was evaluated. Between 22 February and 2 May 2021, CC sites implemented SARS-CoV-2 voluntary screening of their asymptomatic HCWs. On-site testing with Abbott Panbio or BD Veritor occurred on a weekly or twice-weekly basis. Positive APOCTs were confirmed with a real-time reverse transcriptase PCR (rRT-PCR) reference method. A total of 71,847 APOCTs (17,689 Veritor and 54,158 Panbio) were performed among 369 CC sites. Eighty-seven (0.12%) APOCTs were positive, of which 39 (0.05%) were confirmed as true positives using rRT-PCR. Use of the Veritor and Panbio resulted in 76.6% and 30.0% false-positive detection, respectively (P < 0.001). This corresponded to PPVs of 23.4 and 70.0% for the Veritor and Panbio, respectively. Frequent screening of SARS-CoV-2 among asymptomatic HCWs in CC, using APOCTs, resulted in a very low detection rate and a high rate of detection of false positives. Careful assessment of the risks versus benefits of APOCT programs and the prevalence of infection in this population needs to be thoroughly considered before implementation.
Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , Pruebas en el Punto de Atención , Valor Predictivo de las Pruebas , Sensibilidad y EspecificidadRESUMEN
SARS-CoV-2 antigen tests used at the point-of-care, such as the Abbott Panbio, have great potential to help combat the COVID-19 pandemic. The Panbio is Health Canada approved for the detection of SARS-CoV-2 in symptomatic individuals within the first 7 days of COVID-19 symptom onset(s). Symptomatic adults recently diagnosed with COVID-19 in the community were recruited into the study. Paired nasopharyngeal (NP), throat, and saliva swabs were collected, with one paired swab tested immediately with the Panbio, and the other transported in universal transport media and tested using real-time reverse-transcriptase polymerase chain reaction (RT-PCR). We also prospectively evaluated results from assessment centers within the community. For those individuals, an NP swab was collected for Panbio testing and paired with RT-PCR results from parallel NP or throat swabs. One hundred and forty-five individuals were included in the study. Collection of throat and saliva was stopped early due to poorer performance (throat sensitivity 57.7%, n=61, and saliva sensitivity 2.6%, n=41). NP swab sensitivity was 87.7% [n=145, 95% confidence interval (CI) 81.0-92.7%]. There were 1641 symptomatic individuals tested by Panbio in assessment centers with 268/1641 (16.3%) positive for SARS-CoV-2. There were 37 false negatives and 2 false positives, corresponding to a sensitivity and specificity of 86.1% [95% CI 81.3-90.0%] and 99.9% [95% CI 99.5-100.0%], respectively. The Panbio test reliably detects most cases of SARS-CoV-2 from adults in the community setting presenting within 7 days of symptom onset using nasopharyngeal swabs. Throat and saliva swabs are not reliable specimens for the Panbio.
Asunto(s)
Prueba de COVID-19 , COVID-19/diagnóstico , Nasofaringe/virología , Faringe/virología , Saliva/virología , Adulto , Anciano , Anciano de 80 o más Años , Canadá , Reacciones Falso Negativas , Reacciones Falso Positivas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Sensibilidad y Especificidad , Manejo de EspecímenesRESUMEN
Meningioma is the most common brain tumor in adults. Surgical resection remains the primary treatment. No chemotherapy exists. However, gene mutations now could explain ~ 80% of meningioma and targeted therapies based on these are being investigated. Furthermore, with the recent discovery of PD-L1 in malignant meningioma, clinical trials using immunotherapy have commenced. Here, we report for the first time the expression profiles of immune checkpoint proteins PD-L2, B7-H3 and CTLA-4 in meningioma and their association to common gene mutations. PD-L2 and B7-H3 expression was significantly greater than all immune checkpoint proteins studied, and particularly elevated in patients with gene mutations affecting the PI3K/AKT/mTOR pathway. CTLA-4 expressing CD3+ lymphocytes were observed in atypical and malignant meningioma and tumors harboring a PIK3CA or SMO mutation. These results identify novel targets for immunotherapy irrespective of grade and distinguish potential patient populations based on genetic classification for stratification into checkpoint inhibitor clinical trials.
RESUMEN
BACKGROUND: Meningioma, a most common brain tumor, has a high rate of recurrence. Tumor-associated macrophages (TAMs) are the most abundant immune cell type in meningioma. TAMs display functional phenotypic diversity and may establish either an inflammatory and anti-tumoral or an immunosuppressive and pro-tumoral microenvironment. TAM subtypes present in meningioma and potential contribution to growth and recurrence is unknown. METHODS: Immunofluorescence staining was used to quantify M1 and M2 TAM populations in tissues obtained from 30 meningioma patients. Associations between M1 and M2 cells, M1:M2 cell ratio to tumor characteristics, WHO grade, recurrence, size, location, peri-tumoral edema, and patient demographics such as age and sex were examined. RESULTS: TAM cells accounted for ~18% of all cells in meningioma tissues. More than 80% of infiltrating TAMs were found to be of pro-tumoral M2 phenotype and correlated to tumor size (P = .0409). M1:M2 cell ratio was significantly decreased in WHO grade II, compared to grade I tumors (P = .009). Furthermore, a 2.3-fold difference in M1:M2 ratio between primary (0.14) and recurrent (0.06) tumors was observed (n = 18 and 12 respectively, P = .044). CONCLUSION: This study is the first to confirm existence of pro-tumoral M2 TAMs in the meningioma microenvironment, emphasizing its potential role in tumor growth and recurrence.
RESUMEN
Meningioma, a common primary brain tumor in adults, is graded based on World Health Organization criteria that rely on histology alone. This approach is unable to determine conclusively which tumors, especially benign or atypical, will recur. Molecular characterization of meningioma has identified genetic biomarkers that can predict tumor behavior. Only a few genetic changes are known to classify >85% of all meningioma and clinical trials using targeted therapy to genetic subtypes of meningioma are under way. Immunotherapy is also being trialed in treating high-grade and recurrent meningioma. This review summarizes recent developments characterizing meningioma using genetic and immunologic biomarkers and how these molecular tools may be integrated into existing care together with current World Health Organization grading to improve diagnosis, prognosis, and therapy.
Asunto(s)
Neoplasias Meníngeas , Meningioma , Humanos , Inmunoterapia/métodos , Imagen por Resonancia Magnética , Neoplasias Meníngeas/clasificación , Neoplasias Meníngeas/diagnóstico , Neoplasias Meníngeas/genética , Neoplasias Meníngeas/terapia , Meningioma/clasificación , Meningioma/diagnóstico , Meningioma/genética , Meningioma/terapia , PronósticoRESUMEN
This study reports vibration profiles of neuronal cells and tissues as well as brain tumor and neocortical specimens. A contact-free method and analysis protocol was designed to convert an atomic force microscope into an ultra-sensitive microphone with capacity to record and listen to live biological samples. A frequency of 3.4 Hz was observed for both cultured rat hippocampal neurons and tissues and vibration could be modulated pharmacologically. Malignant astrocytoma tissue samples obtained from operating room, transported in artificial cerebrospinal fluid, and tested within an hour, vibrated with a much different frequency profile and amplitude, compared to meningioma or lateral temporal cortex providing a quantifiable measurement to accurately distinguish the three tissues in real-time. Vibration signals were converted to audible sound waves by frequency modulation, thus demonstrating, acoustic patterns unique to meningioma, malignant astrocytoma and neocortex.
Asunto(s)
Astrocitoma/patología , Neoplasias Encefálicas/patología , Meningioma/patología , Neocórtex/fisiología , Patología/métodos , Sonido , Vibración , Animales , Astrocitoma/diagnóstico , Neoplasias Encefálicas/diagnóstico , Pruebas Diagnósticas de Rutina/métodos , Meningioma/diagnóstico , RatasRESUMEN
Axonal transsynaptic signaling between presynaptic neurexin (NX) and postsynaptic neuroligin (NL) is essential for many properties of synaptic connectivity. Here, we demonstrate the existence of a parallel axo-glial signaling pathway between axonal NX and oligodendritic (OL) NL3. We show that this pathway contributes to the regulation of myelinogenesis, the maintenance of established myelination, and the differentiation state of the OL using in vitro models. We first confirm that NL3 mRNA and protein are expressed in OLs and in OL precursors. We then show that OLs in culture form contacts with non-neuronal cells exogenously expressing NL3's binding partners NX1α or NX1ß. Conversely, blocking axo-glial NX-NL3 signaling by saturating NX with exogenous soluble NL protein (NL-ECD) disrupts interactions between OLs and axons in both in vitro and ex vivo assays. Myelination by OLs is tied to their differentiation state, and we find that blocking NX-NL signaling with soluble NL protein also caused OL differentiation to stall at an immature stage. Moreover, in vitro knockdown of NL3 in OLs with siRNAs stalls their development and reduces branching complexity. Interestingly, inclusion of an autism related mutation in the NL blocking protein attenuates these effects; OLs differentiate and the dynamics of OL-axon signaling occur normally as this peptide does not disrupt NX-NL3 axo-glial interactions. Our findings provide evidence not only for a new pathway in axo-glial communication, they also potentially explain the correlation between altered white matter and autism. GLIA 2015;63:2023-2039.
RESUMEN
Alzheimer's disease (AD) is characterized clinically by an insidious decline in cognition. Much attention has been focused on proposed pathogenic mechanisms that relate Aß plaque and neurofibrillary tangle pathology to cognitive symptoms, but compelling evidence now identifies early synaptic loss and dysfunction, which precede plaque and tangle formation, as the more probable initiators of cognitive impairment. Glutamate-mediated transmission is severely altered in AD. Glutamate receptor expression is most markedly altered in regions of the AD brain that show the greatest pathological changes. Signaling via glutamate receptors controls synaptic strength and plasticity, and changes in these parameters are likely to contribute to memory and cognitive deficits in AD. Glutamate receptor expression and activity are modulated by interactions with post-synaptic scaffolding proteins that augment the strength and direction of signal cascades initiated by glutamate receptor activity. Scaffold proteins offer promising targets for more focused and effective drug therapy. In consequence, interest is developing into the roles these proteins play in neurological disease. In this review we discuss disruptions to excitatory neurotransmission at the level of glutamate receptor-post-synaptic scaffolding protein interactions that may contribute to synaptic dysfunction in AD.
Asunto(s)
Enfermedad de Alzheimer/patología , Enfermedad de Alzheimer/fisiopatología , Receptores de Glutamato/metabolismo , Sinapsis/metabolismo , Sinapsis/patología , Péptidos beta-Amiloides/metabolismo , Animales , Humanos , Potenciación a Largo Plazo/fisiología , Proteínas de la Membrana/metabolismo , Receptores AMPA/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismoRESUMEN
N-methyl-D-aspartate (NMDA) receptor-evoked excitotoxicity contributes to region-specific loss of glutamatergic synapses responsible for cognitive decline in Alzheimer's disease (AD). Here, the post-synaptic scaffold proteins PSD-95 and SAP-102, which regulate NMDA receptor synaptic activity and expression, were investigated in human AD autopsy brain tissue. Using absolute quantification real-time PCR, we detected reduced expression of synaptophysin in both the pathologically susceptible inferior temporal cortex and hippocampus, consistent with previous reports. PSD-95 and SAP-102 mRNA was reduced, albeit not significantly. Proteins were precisely quantified against recombinant truncated protein standards. No differences were observed for proteins in AD spared occipital cortex between AD cases and controls. PSD-95 and SAP-102 protein expression was markedly reduced in the AD inferior temporal cortex. Both mRNA and protein levels were reduced according to disease severity. SAP102 protein levels were significantly reduced in AD subjects carrying a copy of the APOEε4 allele. This is the first study to investigate SAP-102 in the aging human brain and suggest a possible mechanism for NMDA receptor expression aberrations in AD.
Asunto(s)
Enfermedad de Alzheimer/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas Nucleares/metabolismo , Lóbulo Temporal/metabolismo , Factores de Transcripción/metabolismo , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/patología , Análisis de Varianza , Homólogo 4 de la Proteína Discs Large , Genotipo , Hipocampo/metabolismo , Hipocampo/patología , Humanos , Péptidos y Proteínas de Señalización Intracelular/genética , Proteínas de la Membrana/genética , Proteínas Nucleares/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sinapsis/genética , Sinapsis/metabolismo , Sinapsis/patología , Sinaptofisina/metabolismo , Lóbulo Temporal/patología , Factores de Transcripción/genéticaRESUMEN
Glycerotoxin (GLTx) is capable of stimulating neurotransmitter release at the frog neuromuscular junction by directly interacting with N-type Ca2+ (Cav2.2) channels. Here we have utilized GLTx as a tool to investigate the functionality of Cav2.2 channels in various mammalian neuronal preparations. We first adapted a fluorescent-based high-throughput assay to monitor glutamate release from rat cortical synaptosomes. GLTx potently stimulates glutamate secretion and Ca2+ influx in synaptosomes with an EC50 of 50 pm. Both these effects were prevented using selective Cav2.2 channel blockers suggesting the functional involvement of Cav2.2 channels in mediating glutamate release in this system. We further show that both Cav2.1 (P/Q-type) and Cav2.2 channels contribute equally to depolarization-induced glutamate release. We then investigated the functionality of Cav2.2 channels at the neonatal rat neuromuscular junction. GLTx enhances both spontaneous and evoked neurotransmitter release causing a significant increase in the frequency of postsynaptic action potentials. These effects were blocked by specific Cav2.2 channel blockers demonstrating that either GLTx or its derivatives could be used to selectively enhance the neurotransmitter release from Cav2.2-expressing mammalian neurons.
Asunto(s)
Canales de Calcio Tipo L/biosíntesis , Regulación de la Expresión Génica/efectos de los fármacos , Neuronas Motoras/metabolismo , Neurotransmisores/metabolismo , Animales , Canales de Calcio Tipo L/genética , Canales de Calcio Tipo N , Relación Dosis-Respuesta a Droga , Regulación de la Expresión Génica/fisiología , Ácido Glutámico/metabolismo , Proteínas del Helminto , Técnicas In Vitro , Masculino , Neuronas Motoras/efectos de los fármacos , Neurotoxinas/farmacología , Ratas , Ratas Wistar , Venenos de Serpiente/farmacología , Sinaptosomas/efectos de los fármacos , Sinaptosomas/metabolismo , PonzoñasRESUMEN
Recent discoveries of different modes of exocytosis and a plethora of molecules involved in neurotransmitter release has resulted in demand for more rapid and efficient methods for monitoring endogenous glutamate release from various tissue sources. In this article, we describe a high throughput microplate version of the enzyme-linked fluorescence detection method for the measurement of released glutamate, which utilises glutamate dehydrogenase, and the reduction of NADP to NADPH. Previous versions of this method rely upon cuvette-based fluorimeters for detection that are limited by large sample volumes and small numbers of samples that can be measured simultaneously. Comparison between the two methods shows that the microplate assay has comparable performance to the cuvette-based assay but has the capacity to analyse many times more samples in a given run. This increased capacity provides improved experimental design opportunities, higher experimental throughput and better comparison between experimental conditions.