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1.
Anal Biochem ; 502: 36-42, 2016 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-26945834

RESUMEN

In this research article, a novel, selective, and sensitive modified carbon paste electrode (CPE) using CdS quantum dots (QDs) is presented. The highly stable CdS QDs were successfully synthesized in an in situ process using Na2S2O3 as a precursor and thioglycolic acid as a catalyst and capping agent. The synthesis of CdS QDs was studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. The synthesized CdS QDs were used for preparation of a modified carbon paste electrode (CdS/CPE). The electrochemical behavior of the electrode toward p-aminophenol (PAP) and acetaminophen (Ac) was studied, and the results demonstrated that the CdS/CPE exhibited good electrocatalytic performance toward PAP and Ac oxidation. The oxidation peak potential of each analyte in the mixture was well separated. As a result, a selective and reliable method was developed for the determination of PAP and Ac simultaneously without any chemical separations. Application of the fabricated electrode for monitoring the process of Ac preparation from PAP was investigated. The obtained results show that CdS/CPE has satisfactory analytical performance; it could be a kind of attractive and promising nanomaterial-based sensor for process monitoring via the electrochemical approach.


Asunto(s)
Acetaminofén/síntesis química , Compuestos de Cadmio/química , Carbono/química , Puntos Cuánticos , Sulfuros/química , Acetaminofén/química , Electrodos , Tamaño de la Partícula , Propiedades de Superficie
2.
Mol Psychiatry ; 20(11): 1311-21, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25917366

RESUMEN

Cognitive impairments are a major clinical feature of the common neurogenetic disease neurofibromatosis type 1 (NF1). Previous studies have demonstrated that increased neuronal inhibition underlies the learning deficits in NF1, however, the molecular mechanism underlying this cell-type specificity has remained unknown. Here, we identify an interneuron-specific attenuation of hyperpolarization-activated cyclic nucleotide-gated (HCN) current as the cause for increased inhibition in Nf1 mutants. Mechanistically, we demonstrate that HCN1 is a novel NF1-interacting protein for which loss of NF1 results in a concomitant increase of interneuron excitability. Furthermore, the HCN channel agonist lamotrigine rescued the electrophysiological and cognitive deficits in two independent Nf1 mouse models, thereby establishing the importance of HCN channel dysfunction in NF1. Together, our results provide detailed mechanistic insights into the pathophysiology of NF1-associated cognitive defects, and identify a novel target for clinical drug development.


Asunto(s)
Trastornos del Conocimiento/tratamiento farmacológico , Trastornos del Conocimiento/metabolismo , Canales Regulados por Nucleótidos Cíclicos Activados por Hiperpolarización/metabolismo , Neurofibromatosis 1/complicaciones , Canales de Potasio/metabolismo , Animales , Trastornos del Conocimiento/etiología , Trastornos del Conocimiento/genética , Modelos Animales de Enfermedad , Antagonistas de Aminoácidos Excitadores/uso terapéutico , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Potenciales Postsinápticos Excitadores/genética , Hipocampo/citología , Canales Regulados por Nucleótidos Cíclicos Activados por Hiperpolarización/genética , Lamotrigina , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Aprendizaje por Laberinto/fisiología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Actividad Motora/efectos de los fármacos , Actividad Motora/genética , Mutación/genética , Inhibición Neural/efectos de los fármacos , Inhibición Neural/genética , Neurofibromatosis 1/genética , Neurofibromina 1/genética , Neurofibromina 1/metabolismo , Plasticidad Neuronal/efectos de los fármacos , Plasticidad Neuronal/genética , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Canales de Potasio/genética , Pirimidinas/farmacología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Triazinas/uso terapéutico
3.
Phys Rev Lett ; 113(10): 107203, 2014 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-25238382

RESUMEN

Uniquely in Cu2OSeO3, the Skyrmions, which are topologically protected magnetic spin vortexlike objects, display a magnetoelectric coupling and can be manipulated by externally applied electric (E) fields. Here, we explore the E-field coupling to the magnetoelectric Skyrmion lattice phase, and study the response using neutron scattering. Giant E-field induced rotations of the Skyrmion lattice are achieved that span a range of ∼25°. Supporting calculations show that an E-field-induced Skyrmion distortion lies behind the lattice rotation. Overall, we present a new approach to Skyrmion control that makes no use of spin-transfer torques due to currents of either electrons or magnons.

4.
Braz J Biol ; 84: e272093, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37283408

RESUMEN

This study aimed to identify the best genotypes using the genotype × yield × trait (GYT) method. To investigate the relationships was performed between yield × traits in four regions of Karaj, Birjand, Shiraz and Arak in two cropping years in a randomized complete block design (RCBD) with three replications. The average grain yield in four regions and two years of the experiment was calculated as 5966 kg/ha, and GYT was obtained based on the multiplication of grain yield with different traits. Comparing the average effect of genotype × year in different environments showed that KSC703 and KSC707 hybrids are among the most productive hybrids among the studied genotypes in grain yield. By examining the correlation coefficients between yield × traits in the tested areas, Y × TWG with Y × GW, Y × NRE, Y × NGR and Y × EL, Y × ED with Y × NGR, Y × NRE with Y × GW and the combination of Y × GW with Y × GL had a positive and significant correlation in all regions. The correlation diagrams were drawn on the evaluated areas' data and showed the correlation of most compounds except Y × GT with each other. Based on the analysis of the main components, the first three components explained the greatest diversity in the population. They were named the component ear grain profile, grain thickness component and plant height profile component.


Asunto(s)
Grano Comestible , Zea mays , Grano Comestible/genética , Genotipo , Fenotipo , Zea mays/genética
6.
J Hosp Infect ; 110: 165-171, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33561503

RESUMEN

BACKGROUND: We investigated the clinical characteristics and risk factors for the isolation of multi-drug-resistant (MDR) Gram-negative bacteria (GNB) from critically ill COVID-19 patients. METHODS: We retrospectively matched (1:2) critical COVID-19 patients with one or more MDR GNB from any clinical specimen (cases), with those with no MDR GNB isolates (controls). RESULTS: Seventy-eight cases were identified (4.5 per 1000 intensive care unit (ICU) days, 95% confidence interval (CI) 3.6-5.7). Of 98 MDR GNB isolates, the most frequent species were Stenotrophomonas maltophilia (24, 24.5%), and Klebsiella pneumoniae (23, 23.5%). Two (8.7%) K. pneumoniae, and six (85.7%) Pseudomonas aeruginosa isolates were carbapenem resistant. A total of 24 (24.5%) isolates were not considered to be associated with active infection. Those with active infection received appropriate antimicrobial agents within a median of one day. The case group had significantly longer median central venous line days, mechanical ventilation days, and hospital length of stay (P<0.001 for each). All-cause mortality at 28 days was not significantly different between the two groups (P=0.19). Mechanical ventilation days (adjusted odds ratio 1.062, 95% CI 1.012-1.114; P=0.015), but not receipt of corticosteroids or tocilizumab, was independently associated with the isolation of MDR GNB. There was no association between MDR GNB and 28-day all-cause mortality (adjusted odds ratio 2.426, 95% CI 0.833-7.069; P= 0.104). CONCLUSION: In critically ill COVID-19 patients, prevention of MDR GNB colonization and infections requires minimizing the use of invasive devices, and to remove them as soon as their presence is no longer necessary.


Asunto(s)
COVID-19/epidemiología , COVID-19/microbiología , COVID-19/fisiopatología , Enfermedad Crítica , Farmacorresistencia Bacteriana Múltiple , Bacterias Gramnegativas/aislamiento & purificación , Infecciones por Bacterias Gramnegativas/epidemiología , Adulto , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Prevalencia , Qatar/epidemiología , Estudios Retrospectivos , Factores de Riesgo , SARS-CoV-2
7.
Rev Pneumol Clin ; 74(2): 61-66, 2018 Apr.
Artículo en Francés | MEDLINE | ID: mdl-29526343

RESUMEN

During the esmo congress that took place from 08 to 12 September 2017 in Madrid, non-small cell lung cancer (NSCLC) was the subject of various communications and posters. We selected the most innovative and most likely to change our daily practice These updates presented concerned both localized and metastatic lung cancers. For completely resected localized stages minimal monitoring by annual CT scan is recommended, in stage III after radio chemotherapy durvalumab treatment provides better progression-free survival (PFS). For metastatic stages, pembroluzumab immunotherapy plus platinum-based chemotherapy in first-line is superior to chemotherapy alone in terms of response rate, second-line treatment with nivolumab provides better overall survival (OS) at 3years, the duration of 1year is characterized by a PFS lower than a continuous treatment. In EGFR mutated NSCLCs, the best choice between 3rd and 1st generation EGFR antigen has generated a lot of debate after the interesting results in terms of progression-free survival (PFS) of osamertinib in 1st metastatic line as well as for NSCLC with ALK rearrangement, alectinib was superior to crizotinib in the first metastatic line even in the presence of brain metastases.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carcinoma de Pulmón de Células no Pequeñas/terapia , Neoplasias Pulmonares/terapia , Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Carcinoma de Pulmón de Células no Pequeñas/patología , Terapia Combinada/métodos , Congresos como Asunto , Humanos , Inmunoterapia/métodos , Neoplasias Pulmonares/mortalidad , Neoplasias Pulmonares/patología , Mutación , Recurrencia Local de Neoplasia/terapia , Tasa de Supervivencia
8.
Neuroscience ; 145(3): 824-31, 2007 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-17289274

RESUMEN

The role of endogenous opioid peptides in impairment of spatial performance due to epileptogenesis was examined. Animals were kindled by repeated injections of pentylenetetrazol (PTZ) (40 mg/kg, i.p.) in the presence or absence of the opioid receptor antagonist naloxone. Naloxone in different doses (1, 5 and 10 mg/kg, i.p.) was applied 30 min before each PTZ injection. Behavioral testing was assessed 24 h and 10 days after the last injection in separate groups of animals using Morris water maze. Our results showed that PTZ-induced kindling produced a significant impairment of spatial learning and memory as compared with controls and this effect was not due to the aftereffect of repeated seizures. Naloxone pretreatment in the course of kindling had no effect on seizures development, however it caused an improvement of spatial learning and memory performance in kindled rats. It is likely that the long-lasting changes in neuronal responsiveness associated with kindling led to a defect in the processing of spatial information. These data suggest that endogenous opioid peptides released in the hippocampus during kindling are at least in part responsible for impairment of spatial performance in kindled animals.


Asunto(s)
Excitación Neurológica/fisiología , Naloxona/farmacología , Pentilenotetrazol/farmacología , Percepción Espacial/efectos de los fármacos , Animales , Excitación Neurológica/efectos de los fármacos , Cinética , Masculino , Ratas , Ratas Endogámicas
9.
J Hosp Infect ; 91(3): 188-96, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26452615

RESUMEN

The Middle East Respiratory Coronavirus (MERS-CoV) was first isolated from a patient who died with severe pneumonia in June 2012. As of 19 June 2015, a total of 1,338 MERS-CoV infections have been notified to the World Health Organization (WHO). Clinical illness associated with MERS-CoV ranges from mild upper respiratory symptoms to rapidly progressive pneumonia and multi-organ failure. A significant proportion of patients present with non-respiratory symptoms such as headache, myalgia, vomiting and diarrhoea. A few potential therapeutic agents have been identified but none have been conclusively shown to be clinically effective. Human to human transmission is well documented, but the epidemic potential of MERS-CoV remains limited at present. Healthcare-associated clusters of MERS-CoV have been responsible for the majority of reported cases. The largest outbreaks have been driven by delayed diagnosis, overcrowding and poor infection control practices. However, chains of MERS-CoV transmission can be readily interrupted with implementation of appropriate control measures. As with any emerging infectious disease, guidelines for MERS-CoV case identification and surveillance evolved as new data became available. Sound clinical judgment is required to identify unusual presentations and trigger appropriate control precautions. Evidence from multiple sources implicates dromedary camels as natural hosts of MERS-CoV. Camel to human transmission has been demonstrated, but the exact mechanism of infection remains uncertain. The ubiquitously available social media have facilitated communication and networking amongst healthcare professionals and eventually proved to be important channels for presenting the public with factual material, timely updates and relevant advice.


Asunto(s)
Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/patología , Infección Hospitalaria/epidemiología , Infección Hospitalaria/patología , Transmisión de Enfermedad Infecciosa , Control de Infecciones/métodos , Coronavirus del Síndrome Respiratorio de Oriente Medio/aislamiento & purificación , Animales , Camelus , Infecciones por Coronavirus/diagnóstico , Infecciones por Coronavirus/transmisión , Infección Hospitalaria/diagnóstico , Infección Hospitalaria/transmisión , Salud Global , Humanos , Zoonosis/epidemiología , Zoonosis/transmisión
10.
Obstet Gynecol ; 95(6 Pt 1): 889-94, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10831986

RESUMEN

OBJECTIVE: To evaluate measurement of levels of urine hyperglycosylated hCG, a form of hCG with abnormally branched oligosaccharide side chains, in conjunction with ultrasound biometry for Down syndrome risk prediction in an at-risk group. METHOD: We prospectively measured urine hyperglycosylated hCG levels, humeral length, and nuchal thickness in women who had second-trimester amniocentesis. Urine hyperglycosylated hCG levels were measured by a two-step enzyme-immunometric assay using monoclonal antibody beta152. Humeral length, nuchal thickness, and hyperglycosylated hCG values were expressed as multiples of the median, and the Down syndrome screening efficiency of the three analytes plus age was determined. A receiver operating characteristic (ROC) curve was generated, and the area under the curve was used to assess the Down syndrome screening performance of the algorithm. RESULTS: There were 23 cases of Down syndrome among 1016 singleton pregnancies. Mean gestational age (+/- standard deviation) was 16.1 +/- 1.2 weeks at the time of amniocentesis. Mean maternal age was 37.1 +/- 3.2 years. Biometry and measurement of hyperglycosylated hCG levels had a 91.3% detection rate at a 3.2% false-positive rate and a 100% detection rate at a 10.7% false-positive rate. The area under the ROC curve was 0.986 (P <.001), and that for measurement of hyperglycosylated hCG levels plus age was 0.941 (P <.001). The area under the curve was significantly larger with combined biochemical and biometry markers compared with measurement of hyperglycosylated hCG levels plus age alone (P <.02), proving that the former was superior to the latter. CONCLUSION: A new Down syndrome biochemical marker combined with ultrasound biometry had a high screening efficiency in a high-risk group. All cases of Down syndrome in this study population would have been detected at an amniocentesis rate of less than 10.7%. Our results appear superior to those found with other second-trimester algorithms. The combination is promising as an alternative to "automatic" genetic amniocentesis in women of advanced maternal age and other high-risk groups.


Asunto(s)
Gonadotropina Coriónica/orina , Síndrome de Down/diagnóstico , Diagnóstico Prenatal , Ultrasonografía Prenatal , Adulto , Biomarcadores , Biometría/métodos , Femenino , Glicosilación , Humanos , Persona de Mediana Edad , Embarazo , Segundo Trimestre del Embarazo , Estudios Prospectivos , Curva ROC
11.
Brain Res ; 877(2): 176-83, 2000 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-10986330

RESUMEN

The effects of pentylenetetrazol (PTZ) following induction of long-term potentiation (LTP) on population spikes in CA1 of hippocampal slices were investigated. Population spikes were evoked by activation of Schaffer collaterals with a range of stimulation intensities. LTP was induced using θ-pattern primed burst tetanic stimulation. Changes in the population spike amplitude and number of population spikes were used as indices to quantify the effects of PTZ exposure in the control (non-tetanized) and LTP (tetanized) conditions. The amplitude of population spike was measured 20 min before, during 20 min chemical application (3 mM), and also after 30 or 60 min washout period. In non-tetanized slices, the population spike input-output curve was significantly increased 20 min after PTZ application and persisted at least for 60 min. Multiple population spikes or after potentials also appeared, but did not persist. When PTZ was applied on tetanized slices, 60 min after LTP induction, the amplitude increase produced by PTZ was smaller than the increase seen in the control condition. Also LTP induction preceding PTZ exposure increased the number of population spikes evoked by stimulation of Schaffer collaterals. It is concluded that a transient PTZ application produces a long-lasting increase in population spike amplitude. Primed burst LTP occludes PTZ-induced potentiation while also increasing the epileptogenic effect of PTZ.


Asunto(s)
Epilepsia/inducido químicamente , Hipocampo/efectos de los fármacos , Potenciación a Largo Plazo/efectos de los fármacos , Células Piramidales/efectos de los fármacos , Potenciales de Acción/efectos de los fármacos , Potenciales de Acción/fisiología , Animales , Axones/efectos de los fármacos , Axones/fisiología , Estimulación Eléctrica , Epilepsia/fisiopatología , Hipocampo/citología , Hipocampo/fisiología , Potenciación a Largo Plazo/fisiología , Masculino , Pentilenotetrazol/farmacología , Células Piramidales/citología , Células Piramidales/fisiología , Ratas , Ratas Endogámicas , Transmisión Sináptica/efectos de los fármacos , Transmisión Sináptica/fisiología
12.
Clin Oncol (R Coll Radiol) ; 26(6): 333-43, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24746747

RESUMEN

AIMS: To investigate patterns of practice in palliative radiotherapy in Africa. MATERIALS AND METHODS: Fifteen centres in Africa provided detailed information about radiotherapy in both metastatic and locally advanced disease via a questionnaire. Information included general information (institution status, equipment, staff, patient number), radiotherapy and other treatment characteristics in bone metastasis, brain metastasis, metastatic spinal cord compression, lung and liver metastasis, as well as locally advanced tumours. RESULTS: The number of patients annually seen/treated ranged from 285 to 5000. Breast, cervix, head and neck, gastrointestinal and prostate cancer were the top five cancers overall. Eight (53%) institutions were without linear accelerators, four (27%) had a single one, whereas one institution each had two, three and four linear accelerators. The number of cobalt machines ranged from 0 to 2 (median 1). Most centres still prefer to use fractionated radiotherapy regimens over single-fraction regimens in bone metastasis, although most centres are now using single-fraction radiotherapy in retreatments. Radiotherapy in brain metastasis and metastatic spinal cord compression mostly conform to worldwide standards. Lung and liver metastases are rarely irradiated, largely as a consequence of the lack of modern radiotherapy technology. Locally advanced disease in various tumour sites was mostly palliated, in agreement with current evidence-based practices. CONCLUSIONS: African countries still lack adequate staffing and equipment to adequately address their clinical burden, being palliative in most cases. Emphasis should also be made on more rationally using existing capacities by using more of the single-fraction radiotherapy regimens, especially in bone metastasis.


Asunto(s)
Metástasis de la Neoplasia/radioterapia , Neoplasias/radioterapia , Cuidados Paliativos/estadística & datos numéricos , África , Países en Desarrollo , Fraccionamiento de la Dosis de Radiación , Femenino , Humanos , Masculino , Cuidados Paliativos/métodos , Encuestas y Cuestionarios
13.
J Phys Condens Matter ; 24(43): 432201, 2012 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-23032155

RESUMEN

Small-angle neutron scattering has been employed to study the influence of applied electric (E-)fields on the skyrmion lattice in the chiral lattice magnetoelectric Cu(2)OSeO(3). Using an experimental geometry with the E-field parallel to the [111] axis, and the magnetic field parallel to the [11(-)0] axis, we demonstrate that the effect of applying an E-field is to controllably rotate the skyrmion lattice around the magnetic field axis. Our results are an important first demonstration for a microscopic coupling between applied E-fields and the skyrmions in an insulator, and show that the general emergent properties of skyrmions may be tailored according to the properties of the host system.

16.
Phytomedicine ; 13(3): 146-51, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16428020

RESUMEN

Using field potential recording in the CA1 region of the rat hippocampal slices, the effects of eugenol on synaptic transmission and long-term potentiation (LTP) were investigated. Population spikes (PS) were recorded in the stratum pyramidal following stimulation of stratum fibers. To induce LTP, eight episodes of theta pattern primed-bursts (PBs) were delivered. Eugenol decreased the amplitude of PS in a concentration-dependent manner. The effect was fast and completely reversible. Eugenol had no effect on PBs-induced LTP of PS. It is concluded that while eugenol depresses synaptic transmission it does not affect the ability of CA1 synapses for tetanus-induced LTP and plasticity.


Asunto(s)
Eugenol/farmacología , Hipocampo/efectos de los fármacos , Potenciación a Largo Plazo/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacos , Potenciales de Acción/efectos de los fármacos , Potenciales de Acción/fisiología , Adenosina/farmacología , Animales , Cromatografía de Gases/métodos , Electrofisiología/métodos , Eugenol/química , Hipocampo/fisiología , Potenciación a Largo Plazo/fisiología , Masculino , Aceites Volátiles/farmacología , Aceites de Plantas/química , Células Piramidales/efectos de los fármacos , Células Piramidales/fisiología , Ratas , Solventes/farmacología , Syzygium/química , Factores de Tiempo
17.
Pediatr Cardiol ; 26(6): 851-5, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16088417

RESUMEN

An active otherwise healthy and middle-aged woman presented with left supraclavicular pulsation, right upper extremity claudication, and mild dysphagia. Evaluation revealed an aberrant right subclavian artery, Kommerell's diverticulum with aneurysmal degeneration, legamentum arteriosum completing vascular ring, and absent left pulmonary artery with multiple collateral supply to the left lung. She underwent successful surgical repair via right thoracotomy, including division of the vascular ring, resection of the diverticulum and aneurysm, and finally reimplantation of the right subclavian artery to the aortic arch. Her symptoms resolved completely, and she was able to resume normal activities.


Asunto(s)
Trastornos de Deglución/etiología , Divertículo Esofágico/complicaciones , Arteria Pulmonar/anomalías , Arteria Subclavia/anomalías , Enfermedades Vasculares/congénito , Síndromes del Arco Aórtico/diagnóstico por imagen , Síndromes del Arco Aórtico/cirugía , Divertículo Esofágico/diagnóstico por imagen , Femenino , Humanos , Persona de Mediana Edad , Arteria Pulmonar/cirugía , Radiografía , Arteria Subclavia/trasplante , Toracotomía , Enfermedades Vasculares/diagnóstico por imagen
18.
Int J Clin Pract ; 53(2): 147-8, 1999 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10344053

RESUMEN

A case is reported in which an undiagnosed bronchogenic carcinoma presented clinically with sudden onset shortness of breath and cardiac failure due to the development of an acute bronchopericardial fistula.


Asunto(s)
Fístula Bronquial/etiología , Carcinoma Broncogénico/complicaciones , Fístula/etiología , Neoplasias Pulmonares/complicaciones , Pericardio , Anciano , Anciano de 80 o más Años , Gasto Cardíaco Bajo/etiología , Disnea/etiología , Femenino , Cardiopatías/complicaciones , Humanos
19.
Prenat Diagn ; 18(9): 926-33, 1998 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9793975

RESUMEN

Hyperglycosylated hCG (H-hCG) is a minor variant of hCG with abnormal oligosaccharide side chains. It is the principal gonadotropin detected in the serum and urine of patients with gestational choriocarcinoma. A monoclonal antibody was produced against this antigen and an immunoassay developed. Levels of hCG and H-hCG were determined in 142 urine samples from normal pregnancies from 10 to 21 weeks of gestation. Levels were normalized to urine creatinine concentration, and were each plotted against gestational age. Bi-weekly median values were calculated, the best-fitting regression lines were determined, and multiples of the normal median (MoM) were computed. 10 Down syndrome pregnancy samples were tested from 11 to 21 weeks of gestation. The median hCG and H-hCG levels in the Down syndrome cases were 1.9 MoM and 5.7 MoM of unaffected cases, respectively. Four of 10 hCG measurements and 9 of 10 H-hCG determinations exceeded the 95th centile of unaffected cases. H-hCG identified 90 per cent of Down syndrome cases with a 5 per cent false-positive rate. This is more than twice the number of cases detected by an hCG assay. H-hCG may be an effective replacement for hCG in antenatal Down syndrome screening. This is a preliminary report consisting of only 152 samples. Further studies are needed now to verify the Down syndrome screening utility of this potentially valuable new marker.


Asunto(s)
Gonadotropina Coriónica/orina , Síndrome de Down/diagnóstico , Diagnóstico Prenatal/métodos , Anticuerpos Monoclonales , Reacciones Falso Positivas , Femenino , Edad Gestacional , Glicosilación , Humanos , Inmunoensayo , Embarazo , Valores de Referencia
20.
Prenat Diagn ; 19(4): 351-9, 1999 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10327141

RESUMEN

Hyperglycosylated hCG is a form of hCG with more complex oligosaccharide side chains. A specific immunoassay was developed to measure hyperglycosylated hCG. Levels were measured in urine samples from 1157 women between 11 to 22 weeks of gestation, undergoing genetic analysis because of advanced maternal age. Values were normalized to urine creatinine concentration and plotted against gestational age, median values were determined and multiples of the control median (MoM) calculated. The median MoM and log standard deviation (log SD) of the 1134 control samples was 1.0 and 0.47, and of the 23 Down syndrome cases was 7.8 and 0.48, respectively. This indicated a 7.8-fold increase in hyperglycosylated hCG levels in Down syndrome cases. In the accompanying article, a stability problem was found with beta-core fragment measurements in frozen urine samples. In anticipation of similar problems, nine urine samples were tested for hyperglycosylated hCG fresh and after storage in the freezer. No clear difference was found in hyperglycosylated hCG values. In addition, no trend was found in hyperglycosylated hCG MoM values or in Down syndrome detection rates in urine samples stored for one, two or three years in the freezer. Samples were split into five equal groups according to creatinine concentration. A trend was observed, hyperglycosylated hCG MoM values decreasing with advancing creatinine concentration (1.77, 1.08, 1.01, 0.73 and 0.60 at 0.25, 0.50, 0.79, 1.11 and 1.73 mg/ml, respectively). An error was noted. This was corrected with a regression equation. After correction, the median MoM and log SD of the control samples was 1.0 and 0.44, and of Down syndrome samples was 7.3 and 0.42, respectively. Correction of this error, while reducing the elevation of Down syndrome cases, tightened the spread of samples. Samples were ranked and centiles determined. 18 of 23 Down syndrome cases (78 per cent) exceeded the 95th centile of the control population. ROC analysis indicated 79 per cent detection at 5 per cent false-positive rate. Urine samples were collected during two periods of gestation, an early period (11th to 14th completed week) and the period when chemical screening is normally performed (15th to 21st week). ROC analysis indicated 80 per cent and 78 per cent detection rates, respectively, at 5 per cent false-positive rate, in the two gestational periods. Hyperglycosylated hCG values were modelled with beta-core fragment values, total oestriol values and maternal age. ROC analysis indicated 97 per cent detection rate at 5 per cent false-positive rate. This detection rate and this level of Down syndrome and control patient discrimination surpasses that of any other serum, urine or ultrasound screening protocol. Hyperglycosylated hCG should be considered as a new screening test for aneuploid pregnancies, with the potential of detecting almost all cases of Down syndrome. Evaluation is needed by other centres in order to bring hyperglycosylated hCG into clinical practice.


Asunto(s)
Gonadotropina Coriónica/orina , Síndrome de Down/orina , Diagnóstico Prenatal/métodos , Creatinina/orina , Estabilidad de Medicamentos , Reacciones Falso Positivas , Femenino , Enfermedades Fetales/orina , Congelación , Edad Gestacional , Humanos , Embarazo , Sensibilidad y Especificidad
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