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1.
Vaccines (Basel) ; 12(7)2024 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-39066381

RESUMEN

Notwithstanding prevalence gaps in micronutrients supporting immune functions, the significance of their deficits/supplementation for the efficacy of vaccines is underinvestigated. Thus, the influence of supplementation combining vitamins C and D, zinc, selenium, manganese, and N-acetyl cysteine on immune correlates/surrogates of protection conferred by a quadrivalent influenza vaccine (QIV) in mice was investigated. The supplementation starting 5 days before the first of two QIV injections given 28 days apart increased the serum titres of total and neutralizing IgG against each of four influenza strains from QIV. Accordingly, the frequencies of germinal center B cells, follicular CD4+ T helper (Th) cells, and IL-21-producing Th cells increased in secondary lymphoid organs (SLOs). Additionally, the supplementation improved already increased IgG response to the second QIV injection by augmenting not only neutralizing antibody production, but also IgG2a response, which is important for virus clearance, through favoring Th1 differentiation as indicated by Th1 (IFN-γ)/Th2 (IL-4) signature cytokine level ratio upon QIV restimulation in SLO cell cultures. This most likely partly reflected antioxidant action of the supplement as indicated by splenic redox status analyses. Thus, the study provides a solid scientific background for further research aimed at repurposing the use of this safe and inexpensive micronutrient combination to improve response to the influenza vaccine.

2.
Magn Reson Med ; 92(1): 361-373, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38376359

RESUMEN

PURPOSE: The coax monopole antenna is presented for body imaging at 7 T. The antenna is fed at one end, eliminating the possibility of cable-coil coupling and simplifying cable routing. Additionally, its flexibility improves loading to the subject. METHODS: Like the coax dipole antenna, an interruption in the shield of the coaxial cable allows the current to extend to the outside of the shield, generating a B1 + field. Matching is achieved using a single inductor at the distal side, and a cable trap enforces the desired antenna length. Finite difference time domain simulations are employed to optimize the design parameters. Phantom measurements are conducted to determine the antenna's B1 + efficiency and to find the S-parameters in straight and bent positions. Eight-channel simulations and measurements are performed for prostate imaging. RESULTS: The optimal configuration is a length of 360 mm with a gap position of 40 mm. Simulation data show higher B1 + levels for the coax monopole (20% in the prostate), albeit with a 5% lower specific absorbance rate efficiency, compared to the fractionated dipole antenna. The S11 of the coax monopole exhibits remarkable robustness to loading changes. In vivo prostate imaging demonstrates B1 + levels of 10-14 µT with an input power of 8 × 800 W, which is comparable to the fractionated dipole antenna. High-quality images and acceptable coupling levels were achieved. CONCLUSION: The coax monopole is a novel, flexible antenna for body imaging at 7 T. Its simple design incorporates a single inductor at the distal side to achieve matching, and one-sided feeding greatly simplifies cable routing.


Asunto(s)
Simulación por Computador , Diseño de Equipo , Imagen por Resonancia Magnética , Fantasmas de Imagen , Humanos , Imagen por Resonancia Magnética/instrumentación , Masculino , Próstata/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador/métodos
3.
Magn Reson Imaging ; 108: 146-160, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38364973

RESUMEN

OBJECTIVE: This study evaluates the performance of a twisted pair transmission line coil as a transceive element for 7 T MRI in terms of physical flexibility, robustness to shape deformations, and interelement decoupling. METHODS: Each coil element was created by shaping a twisted pair of wires into a circle. One wire was interrupted at the top, while the other was interrupted at the bottom, and connected to the matching circuit. Electromagnetic simulations were conducted to determine the optimal number of twists per length (in terms of B1+ field efficiency, SAR efficiency, sensitivity to elongation, and interelement decoupling properties) and for investigating the fundamental operational principle of the coil through fields streamline visualisation. A comparison between the twisted pair coil and a conventional loop coil in terms of B1+ fields, maxSAR10g, and stability of S11 when the coil was deformed was performed. Experimentally measured interelement coupling between individual elements of multichannel arrays was also investigated. RESULTS: Increasing the number of twists per length resulted in a more physically robust coil. Poynting vector streamline visualisation showed that the twisted pair coil concentrated most of the energy in the near field. The twisted pair coil exhibited comparable B1+ fields and improved maxSAR10g to the conventional coil but demonstrated exceptional stability with respect to coil deformation and a strong self-decoupling nature when placed in an array configuration. DISCUSSION: The findings highlight the robustness of the twisted pair coil, showcasing its stability under shape variations. This coil holds great potential as a flexible RF coil for various imaging applications using multiple-element arrays, benefiting from its inherent decoupling.


Asunto(s)
Imagen por Resonancia Magnética , Ondas de Radio , Diseño de Equipo , Imagen por Resonancia Magnética/métodos , Fantasmas de Imagen
4.
Toxicol Appl Pharmacol ; 473: 116598, 2023 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-37331382

RESUMEN

Diazinon is an organophosphate pesticide (OP) that has significant potential for accidental and intentional poisoning of wildlife, domestic animals and humans. The aim of the study is to investigate the correlation between cholinesterase activity and oxidative stress parameters in liver and diaphragm by continuous monitoring as a function of time during prolonged use of diazinon. Wistar rats were treated orally with diazinon (55 mg/kg/day): 7, 14, 21 and 28 days. At the end of each period, blood, liver and diaphragm were collected to examine cholinesterase activity and enzymatic/non-enzymatic oxidative stress parameters: superoxide dismutase 1 (SOD1), catalase (CAT), thiobarbituric acid substances (TBARS), protein carbonyl groups. In all four time periods, there was a significant change in acetylcholinesterase (AChE) in erythrocytes and butyrylcholinesterase (BuChE) in blood plasma, CAT in liver and diaphragm and SOD1 in diaphragm. Parameters significantly altered during the cholinergic crisis included: cholinesterases and TBARS in liver and diaphragm and partially SOD1 in liver. Protein carbonyl groups in liver and diaphragm were significantly altered outside the cholinergic crisis. In the liver, there was a very strong negative correlation between BuChE and TBARS in all four time periods and BuChE and CAT on day 7. In the diaphragm, a very strong negative correlation was found between AChE and TBARS at days 7 and 14, and a very strong positive correlation between AChE and SOD1 at days 14, 21 and 28. A better understanding of the relationship between cholinergic overstimulation and oxidative stress may help to better assess health status in prolonged OPs intoxication.


Asunto(s)
Acetilcolinesterasa , Diazinón , Humanos , Ratas , Animales , Diazinón/toxicidad , Acetilcolinesterasa/metabolismo , Butirilcolinesterasa/metabolismo , Ratas Wistar , Sustancias Reactivas al Ácido Tiobarbitúrico/metabolismo , Superóxido Dismutasa-1/metabolismo , Estrés Oxidativo , Colinérgicos
5.
Can J Surg ; 66(2): E123-E131, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36931652

RESUMEN

BACKGROUND: Delay of emergency surgery contributes to morbidity and mortality, and physiologic status affects outcomes of patients requiring emergent surgery. Our purpose was to determine whether delays to emergent surgery in children were associated with increased major morbidity or mortality in a risk-adjusted population. METHODS: We performed a retrospective review of class 1 (≤ 60 min to operating room) surgical procedures from July 11, 2011, to July 30, 2016, at BC Children's Hospital, Vancouver. Data sources included the operating room database, patient charts, American Society of Anesthesiologists classification, Neonatal Acute Physiology (SNAP II) and Pediatric Risk of Mortality (PRISM III) scores, time from booking to operating room and outcome. Patients were classified as being at low or high risk for death. We defined major morbidity as unintended loss of an organ, limb or function related to surgery, and delay to surgery as more than 60 minutes from booking to in room. We used the χ2 test for univariate analysis and logistic regression for multivariate analysis. RESULTS: There were 384 cases (367 patients), 223 high-risk and 161 low-risk. The median age was 4 years (range 0 d-18 yr). Overall, 184 cases (47.9%) were delayed. Major morbidity occurred in 94 cases (24.5%), and 28 patients (7.6%) (all in the high-risk group) died. The mean time to the operating room was 1.46 hours for patients with major morbidity/mortality and 1.17 hours for those without. After adjustment for risk level, multivariate analysis showed delay to surgery to be associated with 85% increased odds of morbidity and/or mortality (adjusted odds ratio 1.85, 95% confidence interval 1.20-2.94) compared to no delay. CONCLUSION: Delay to emergent surgery was associated with a significant increase in major morbidity and/or mortality. Children who require emergency surgery need their care prioritized by not only operating room teams but also hospitals and government; otherwise, they will continue to experience unintended consequences.


Asunto(s)
Procedimientos Quirúrgicos Operativos , Tiempo de Tratamiento , Niño , Humanos , Recién Nacido , Modelos Logísticos , Morbilidad , Quirófanos , Estudios Retrospectivos , Medición de Riesgo , Factores de Riesgo , Lactante , Preescolar , Adolescente , Mortalidad , Servicio de Urgencia en Hospital
7.
Comp Immunol Microbiol Infect Dis ; 87: 101834, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35716654

RESUMEN

S. pneumoniae is an important human pathogen which has a polysaccharide capsule with virulent properties. This work aims to estimate the titres of S. pneumoniae specific IgG and IgA isotypes, with respect to age and sex. An in-house whole bacterial cell ELISA was used for the determination of relative levels and endpoint titres of IgG subclasses and IgA1 subclass specific for S. pneumoniae serogroup 1, and to quantify specific IgG1 and IgG2 levels. Significantly lower anti-pneumococcus IgG1 titres were found in older individuals, which was more pronounced in men. Lower IgG2 titres were detected in men over 50 years of age, in comparison to women under 50 years of age. The levels of IgG3 and IgG4 did not differ between different sex and age groups. Lower IgA1 levels were detected in male individuals in both age groups in comparison to females under 50 years of age. The levels of IgG1 showed a moderate correlation with IgG4 in younger individuals of both sexes (r = 0.61 in men and 0.63 in women) which was not noted in the older age group. We highlight the deficiency in humoral immunity in older people, especially male and suggest immunization of this population with pneumococcal vaccines.


Asunto(s)
Anticuerpos Antibacterianos , Streptococcus pneumoniae , Animales , Femenino , Humanos , Inmunoglobulina A , Inmunoglobulina G , Masculino , Serogrupo
8.
Life Sci ; 301: 120617, 2022 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-35533760

RESUMEN

AIMS: Given that deprivation of noradrenaline acting on lymphocytes through ß-adrenoceptor influences antibody response, the effects of propranolol treatment beginning two days before immunization with quadrivalent inactivated influenza vaccine (QIV) on IgG response and underlying cellular molecular mechanism in mice were investigated. MAIN METHODS: Twenty-one days post-immunization the total QIV antigen-specific IgG titer and IgG subclass titers in sera were determined using ELISA. Additionally, the total counts of germinal centre (GC) B cells, T follicular helper (Tfh) and T follicular regulatory (Tfr) cells in draining lymph nodes (dLNs) and spleens, in vitro proliferation of interacting B cells and Th cells and IL-21 synthesis in Th cells in response to QIV antigens and/or mitogen were attested using flow cytometry analysis. In QIV antigen-stimulated dLN cell and splenocyte cultures were also measured concentrations of INF-γ and IL-4, cytokines upregulating IgG2a and IgG1 synthesis, respectively. KEY FINDINGS: Propranolol decreased the total QIV antigen-specific IgG titer. This correlated with lower GC B cell count and the shift in Tfr/Tfh cell and Tfr/GC B cell ratio towards Tfr in propranolol-treated mice compared with controls. Consistently, QIV antigen-stimulated proliferation of B cells and Th cells from propranolol-treated mice in vitro was impaired. This correlated with the lower frequency of QIV antigen-specific IL-21-producing cells among Th cells. Additionally, in propranolol-treated mice, in accordance with the changes in INF-γ/IL-4 ratio in dLN cell/splenocyte cultures, serum IgG2a/IgG1 ratio was shifted towards IgG1 reflecting decreased IgG2a response. SIGNIFICANCE: The study indicates that chronic propranolol treatment may impair response to QIV.


Asunto(s)
Vacunas contra la Influenza , Animales , Inmunoglobulina G , Interleucina-4 , Ratones , Propranolol/farmacología , Receptores Adrenérgicos , Estaciones del Año , Linfocitos T Reguladores
9.
MAGMA ; 35(6): 875-894, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-35471464

RESUMEN

This article reviews recent developments in designing and testing new types of materials which can be: (i) placed around the body for in vivo imaging, (ii) be integrated into a conventional RF coil, or (iii) form the resonator itself. These materials can improve the quality of MRI scans for both in vivo and magnetic resonance microscopy applications. The methodological section covers the basic operation and design of two different types of materials, namely high permittivity materials constructed from ceramics and artificial dielectrics/metasurfaces formed by coupled conductive subunits, either in air or surrounded by dielectric material. Applications of high permittivity materials and metasurfaces placed next to the body to neuroimaging and extremity imaging at 7 T, body and neuroimaging at 3 T, and extremity imaging at 1.5 T are shown. Results using ceramic resonators for both high field in vivo imaging and magnetic resonance microscopy are also shown. The development of new materials to improve MR image quality remains an active area of research, but has not yet found significant use in clinical applications. This is mainly due to practical issues such as specific absorption rate modelling, accurate and reproducible placement, and acceptable size/weight of such materials. The most successful area has been simple "dielectric pads" for neuroimaging at 7 T which were initially developed somewhat as a stop-gap while parallel transmit technology was being developed, but have continued to be used at many sites. Some of these issues can potentially be overcome using much lighter metasurfaces and artificial dielectrics, which are just beginning to be assessed.


Asunto(s)
Imagen por Resonancia Magnética , Neuroimagen , Fantasmas de Imagen , Imagen por Resonancia Magnética/métodos , Cerámica , Espectroscopía de Resonancia Magnética
10.
Appl Biochem Biotechnol ; 194(5): 2047-2060, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35013926

RESUMEN

The surface of microorganisms is covered with carbohydrates, which makes them unique, self-sustaining glycan probes. Lectins are able to bind to these probes, and this interaction can be exploited for selecting microorganisms or novel lectins. To examine lectin-microorganism interactions, we have previously developed an enzyme-linked lectin sorbent assay (ELLSA) with whole bacterial cells. To further test the validity of this methodology, here we compare it with flow cytometry. For this purpose, we used biotinylated recombinantly produced lectin from Musa acuminata (BanLec), this lectin's recombinantly produced chimera with green fluorescent protein (BanLec-eGFP) and a lectin from Ricinus communis (RCA120), both biotinylated and FITC labeled. Parallel testing showed equivalent results for the two methods, in terms of the presence or absence of binding, with signal intensity yielding high Pearson correlation coefficient of 0.8 for BanLec and 0.95 for RCA120. The ELLSA method demonstrated multiple advantages, such as reliability and convenience for high-throughput analysis; it also required less lectin and yielded more consistent results. As such, ELLSA proved to be a useful tool for profiling microbial glycan structures or testing novel lectins.


Asunto(s)
Lectinas , Musa , Citometría de Flujo , Lectinas/química , Musa/metabolismo , Lectinas de Plantas/química , Polisacáridos/química , Reproducibilidad de los Resultados
11.
World Neurosurg ; 155: 150-159, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34464771

RESUMEN

BACKGROUND: Global neurosurgery operates at the intersection of neurosurgery and public health. Although most global neurosurgery initiatives have targeted neurosurgeons and trainees, medical students represent the future of global neurosurgery. METHODS: A narrative review of the literature regarding research methodology, education, economics, health policy, health advocacy, relevant to global neurosurgery was conducted. RESULTS: We summarize pearls that all medical students interested in global neurosurgery should know. DISCUSSION: To become effective agents of change within global neurosurgery, medical students must master competencies of motivation, organization, collaborativeness, dependability, flexibility, resilience, creative problem-solving, ethical thinking, cultural humility, and global awareness and gain knowledge and skills regarding research, education, policy making, and advocacy. Discussions with neurosurgeons and trainees, neurosurgery interest groups, conferences, university global neurosurgery initiatives, and student organizations represent opportunities for learning and becoming involved in global neurosurgery.


Asunto(s)
Competencia Clínica , Educación Médica/métodos , Salud Global/educación , Recursos en Salud/tendencias , Neurocirujanos/educación , Procedimientos Neuroquirúrgicos/educación , Educación Médica/tendencias , Salud Global/tendencias , Conocimientos, Actitudes y Práctica en Salud , Disparidades en Atención de Salud/tendencias , Humanos , Neurocirujanos/tendencias , Procedimientos Neuroquirúrgicos/tendencias , Estudiantes de Medicina
12.
J Pediatr Orthop ; 41(6): e392-e397, 2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-34096547

RESUMEN

BACKGROUND: Diagnosis and treatment for developmental dysplasia of the hip (DDH) varies greatly depending on condition severity, age at diagnosis, and professional opinion. Little is known about patient experiences across the globe. We aimed to characterize global patient and caregiver experiences during DDH care and to highlight patient-identified priorities. METHODS: We developed a cross-sectional survey in collaboration with 7 DDH outreach organizations. DDH patients and/or their caregivers (above 18 y old) were invited to complete an international online survey about their experiences. Participants were recruited through web media of all collaborating organizations. Data collection took place over 3 months. Descriptive statistics were used to analyze quantitative results. Qualitative content analysis was used to categorize open-ended responses. RESULTS: A total of 739 participants completed the survey, representing 638 (86.3%) parents/guardians of DDH patients, and 101 (13.7%) patients. Three hundred eighty-six (52.2%) participants received diagnosis by 3 months of age; mean age of diagnosis was 15.96 months (90% confidence interval=12.04, 19.91). Of 211 participants with family history of DDH, 68 (32.3%) did not receive DDH screening. Of 187 patients born breech, 82 (43.9%) did not receive DDH screening. In total, 36/94 (38.3%) participants with both family history and breech birth did not receive DDH screening. Most participants reported treatment (696/730, 95.3%), including bracing (n=461) surgery (n=364), and/or closed reduction (n=141). A total of 144 patients reported >1 surgery; 82 reported >3 surgeries. Participants reported a range of 1 to 400 visits to health care professionals for DDH care across 1 to 66 years. Lack of information and resources on treatment practicalities and timelines, along with emotional burden of diagnosis, were greatest challenges reported. CONCLUSION: Results demonstrate that DDH diagnosis and treatment can pose significant burden on patients and caregivers. Reliable public information is needed to support those affected. Global educational efforts are needed to raise awareness of DDH risk factors, signs, and symptoms among care providers, to increase awareness and improve identification, screening, and monitoring of at-risk children.


Asunto(s)
Cuidadores/psicología , Displasia del Desarrollo de la Cadera/terapia , Adolescente , Adulto , Cuidadores/estadística & datos numéricos , Niño , Preescolar , Estudios Transversales , Luxación Congénita de la Cadera , Humanos , Lactante , Recién Nacido , Masculino , Tamizaje Masivo/estadística & datos numéricos , Persona de Mediana Edad , Factores de Riesgo , Encuestas y Cuestionarios , Adulto Joven
13.
World J Surg ; 45(8): 2386-2397, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-33973069

RESUMEN

BACKGROUND: In 2015, the Lancet Commission on Global Surgery published six global surgery goals, one of which was to provide 80% of the world's population with timely access to the Bellwether Surgical procedures. Little is known about the prevalence or efficacy of subsequent interventions implemented in under-resourced countries to increase timely access to Bellwether surgical procedures. METHODS: A systematic review of articles and grey literature published in MEDLINE, Embase, Cochrane, CINAHL, and Web of Science databases was conducted. Two independent reviewers evaluated 1923 captured abstracts using explicit inclusion and exclusion criteria. Following a thematic analysis, two reviewers conducted data extraction on the eleven manuscripts included in the final review. RESULTS: The studied innovations, sparse in number, centred on improved educational resources, the development of orthopaedic devices, and models for assessing surgical access disparity. Eight papers were centred around timely access to caesarean sections, three around open fracture reduction, and three around laparotomy; all focused on adult populations. Five papers addressed innovations in West Africa, two in East Africa, two in South Asia, and one in Southeast Asia. Common outcome metrics were not used to assess improvements to timely surgical access. CONCLUSIONS: Few published interventions have been implemented since the publication of the 2015 Lancet Commission on Global Surgery goals that have or will longitudinally increase the availability of timely surgical access in Low and Middle-Income Countries (LMIC). Tangible outcome measures in existing literature are lacking. An up-scaling and wider adoption of successful strategies is necessary and possible.


Asunto(s)
Países en Desarrollo , Pobreza , Adulto , Asia , Cesárea , Femenino , Servicios de Salud , Humanos , Embarazo
14.
Toxicon ; 192: 57-65, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33497745

RESUMEN

The MTT assay is routinely used to detect the activity of living cells. While working with Vipera ammodytes venom we detected the reduction of MTT without the presence of cells, in a concentration-dependent manner. By combining non-reducing PAGE, L-amino acid oxidase (LAAO) assays, and standard MTT assays, we established and confirmed that venom MTT reduction is catalyzed by only one enzyme, the LAAO. Even though it was previously known that the dimeric and tetrameric forms of LAAO are active, we conclude that the enzyme is also active in the monomeric form. Our results have led to the definition of a new MTT assay in a microtiter plate for in vitro testing of svLAAO activity i.e. from the venom of the V. ammodytes snake. Potentially, this method can be used for testing hemorrhagic venoms of other snakes as well as the LAAO neutralization capability of appropriate antivenoms.


Asunto(s)
Viperidae , Animales , Antivenenos/farmacología , Hemorragia , Oxidorreductasas , Venenos de Víboras/toxicidad
15.
J Med Biochem ; 39(4): 436-443, 2020 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-33312059

RESUMEN

BACKGROUND: The aim of this study was to compare serum sclerostin concentrations in patients with thyroid dysfunction with euthyroid control subjects and to assess the relationship between sclerostin and markers of bone metabolism (osteocalcin and beta-cross-laps). METHODS: The study included 30 patients with thyroid dysfunction (hypothyroidism, hyperthyroidism and subclinical hyperthyroidism) and ten euthyroid controls. Free thyroxine (FT4) was measured by radioimmunoassay, while thyroid stimulating hormone (TSH) concentration was determined immunoradiometrically. We used an ELISA kit to determine the sclerostin level. The electrochemiluminescence method was applied for measuring the bone markers. RESULTS: Sclerostin levels were significantly lower in hypothyroid patients (p=0.009) and significantly elevated in hyperthyroid patients (p=0.008) compared to control values. Hyperthyroid patients also had higher sclerostin than patients with subclinical hyperthyroidism (p=0.013). Sclerostin concentrations were negatively correlated with TSH levels (r=-0.746, p<0.001), but positively with FT4 (r=0.696, p < 0.001). Moreover, sclerostin was positively associated with osteocalcin (r=0.605, p=0.005) and beta-cross-laps levels (r=0.573, p=0.008) in all thyroid patients. CONCLUSIONS: Serum sclerostin is significantly affected in subjects with thyroid dysfunction. Both sclerostin and thyroid status affect bone homeostasis, which is reflected through the significant correlations with osteocalcin and beta-cross-laps.

16.
J Magn Reson ; 320: 106835, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-33065392

RESUMEN

High-permittivity dielectric pads, i.e., thin, flexible slabs, usually consisting of mixed ceramic powders and liquids, have been previously shown to increase the magnetic field at high and ultra high-fields in regions of low efficiency of transmit coils, thus improving the homogeneity of images. However, their material parameters can change with time, and some materials they contain are bio incompatible. This article presents an alternative approach replacing ceramic mixtures with a low-cost and stable artificial dielectric slab. The latter comprises a stack of capacitive grids realized using multiple printed-circuit boards. Results in this article show that the proposed artificial dielectric structure can obtain the same increase in the local transmit radiofrequency magnetic field distribution in a head phantom at 7 T as the conventional dielectric pad.

17.
Magn Reson Med ; 84(3): 1672-1677, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32052472

RESUMEN

PURPOSE: Imaging the carotid arteries at 7T ideally requires a flexible multichannel array that allows B1-shimming and conforms to different neck sizes. The major challenge is to minimize coupling between closely spaced coils and to make the coupling relatively insensitive to loading conditions. METHODS: We have designed a five-channel flexible transceive array composed of shielded-coaxial-cable coils placed on the anterior part of the neck and conforming to the anatomy. In vivo imaging of the carotid arteries in three subjects has been performed. RESULTS: The measured noise correlation matrices show the decoupling level between the individual elements to be -12.5 dB and better. Anatomical localizer imaging of the carotids shows both carotids in every subject well visualized after B1-shimming. In vivo black-blood, carotid images were acquired with very high in-plane spatial resolution (0.25 × 0.25 mm2 ) with clear depiction of the vessel walls. CONCLUSIONS: The flexibility of the proposed coil has been demonstrated by imaging subjects with different neck circumferences. To the best of our knowledge, the in-plane resolution of 0.25 × 0.25 mm2 is the highest reported at 7T.


Asunto(s)
Arterias Carótidas , Imagen por Resonancia Magnética , Arterias Carótidas/diagnóstico por imagen , Diseño de Equipo , Humanos , Cuello/diagnóstico por imagen , Fantasmas de Imagen
18.
Exp Gerontol ; 133: 110857, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32006634

RESUMEN

Considering variability in vaccine responsiveness across human populations, in respect to magnitude and quality, and importance of vaccines in the elderly, the influence of recipient genetic background on the kinetics of age-related changes in the serum IgG antibody responses to seasonal trivalent inactivated split-virus influenza bulk (TIV) was studied in BALB/c and C57BL/6 mice showing quantitative and qualitative differences in this responses in young adult ages. With ageing the total serum IgG response to influenza viruses declined, in a strain-specific manner, so the strain disparity observed in young adult mice (the greater magnitude of IgG response in BALB/c mice) disappeared in aged mice. However, the sexual dimorphisms in this response (more prominent in females of both strains) remained in aged ones. The strain-specific differences in age-related decline in the magnitude of IgG response to TIV correlated with the number of germinal centre (GC) B splenocytes. The age-related decline in GC B cell number was consistent with the decrease in the proliferation of B cells and CD4+ cells in splenocyte cultures upon restimulation with TIV. Additionally, the age-related decrease in the magnitude of IgG response correlated with the increase in follicular T regulatory (fTreg)/follicular T helper (fTh) and fTreg/GC B splenocyte ratios (reflecting decrease in fTh and GC B numbers without changes in fTreg number), and the frequency of CD4+ splenocytes producing IL-21, a key factor in balancing the B cell and fTreg cell activity. With ageing the avidity of virus influenza-specific antibody increased in females of both strains. Moreover, ageing affected IgG2a/IgG1 and IgG2c/IgG1 ratios (reflecting Th1/Th2 balance) in male BALB/c mice and female C57BL/6 mice, respectively. Consequently, differently from young mice exhibiting the similar ratios in male and female mice, in aged female mice of both strains IgG2a(c)/IgG1 ratios were shifted towards a less effective IgG1 response (stimulated by IL-4 cytokines) compared with males. The age-related alterations in IgG subclass profiles in both strains correlated with those in IFN-γ/IL-4 production level ratio in splenocyte cultures restimulated with TIV. These findings stimulate further research to formulate sex-specific strategies to improve efficacy of influenza vaccine in the elderly.


Asunto(s)
Envejecimiento , Centro Germinal/inmunología , Vacunas contra la Influenza/inmunología , Animales , Anticuerpos Antivirales/sangre , Citocinas/inmunología , Femenino , Inmunoglobulina G/sangre , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Orthomyxoviridae , Caracteres Sexuales , Factores Sexuales , Balance Th1 - Th2
19.
Magn Reson Med ; 83(3): 1135-1146, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-31483530

RESUMEN

PURPOSE: To investigate the use of shielded-coaxial-cable (SCC) coils as elements for multi-channel receive-only and transceive arrays for 7T human MRI and to compare their performance with equivalently sized conventional loop coils. METHODS: The SCC coil element consists of a coaxial loop with interrupted central conductor at the feed-point side and an interrupted shield at the opposite point. Inter-element decoupling, transmit efficiency, and sample heating were compared with results from conventional capacitively segmented loop coils. Three multichannel arrays (a 4-channel receive-only array and 8- and 5-channel transceive arrays) were constructed. Their inter-element decoupling was characterized via measured noise correlation matrices and additionally under different flexing conditions of the coils. Thermal measurements were performed and in vivo images were acquired. RESULTS: The measured and simulated B1+ maps of both SCC and conventional loops were very similar. For all the arrays constructed, the inter-element decoupling was much greater for the SCC elements than the conventional ones. Even under high degrees of flexion, the coupling coefficients were lower than -10 dB, with a much smaller frequency shift than for the conventional coils. CONCLUSION: Arrays constructed from SCC elements are mechanically flexible and much less sensitive to changes of the coil shape from circular to elongated than arrays constructed from conventional loop coils, which makes them suitable for construction of size adjustable arrays.


Asunto(s)
Procesamiento de Imagen Asistido por Computador/métodos , Rodilla/diagnóstico por imagen , Imagen por Resonancia Magnética , Termometría , Algoritmos , Simulación por Computador , Radiación Electromagnética , Diseño de Equipo , Humanos , Fantasmas de Imagen , Reproducibilidad de los Resultados , Relación Señal-Ruido
20.
Mol Genet Genomic Med ; 7(10): e00961, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31475481

RESUMEN

BACKGROUND: Profiling the entire genome at base pair resolution in a single test offers novel insights into disease by means of dissection of genetic contributors to phenotypic features. METHODS: We performed genome sequencing for a patient who presented with atypical hereditary sensory and autonomic neuropathy, severe epileptic encephalopathy, global developmental delay, and growth hormone deficiency. RESULTS: Assessment of the variants detected by mapped sequencing reads followed by Sanger confirmation revealed that the proband is a compound heterozygote for rare variants within RETREG1 (FAM134B), a gene associated with a recessive form of hereditary sensory and autonomic neuropathy, but not with epileptic encephalopathy or global developmental delay. Further analysis of the data also revealed a heterozygous missense variant in DNM1L, a gene previously implicated in an autosomal dominant encephalopathy, epilepsy, and global developmental delay and confirmed by Sanger sequencing to be a de novo variant not present in parental genomes. CONCLUSIONS: Our findings emphasize the importance of genome-wide sequencing in patients with a well-characterized genetic disease with atypical presentation. This approach reduces the potential for misdiagnoses.


Asunto(s)
Dinaminas/genética , Neuropatías Hereditarias Sensoriales y Autónomas/diagnóstico , Epilepsia Generalizada/complicaciones , Epilepsia Generalizada/diagnóstico , Epilepsia Generalizada/genética , Neuropatías Hereditarias Sensoriales y Autónomas/complicaciones , Neuropatías Hereditarias Sensoriales y Autónomas/genética , Heterocigoto , Humanos , Péptidos y Proteínas de Señalización Intracelular/genética , Masculino , Proteínas de la Membrana/genética , Mutación Missense , Linaje
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