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Triple oxygen isotope ratios Δ'17O offer new opportunities to improve reconstructions of past climate by quantifying evaporation, relative humidity, and diagenesis in geologic archives. However, the utility of Δ'17O in paleoclimate applications is hampered by a limited understanding of how precipitation Δ'7O values vary across time and space. To improve applications of Δ'17O, we present δ18O, d-excess, and Δ'17O data from 26 precipitation sites in the western and central United States and three streams from the Willamette River Basin in western Oregon. In this data set, we find that precipitation Δ'17O tracks evaporation but appears insensitive to many controls that govern variation in δ18O, including Rayleigh distillation, elevation, latitude, longitude, and local precipitation amount. Seasonality has a large effect on Δ'17O variation in the data set and we observe higher seasonally amount-weighted average precipitation Δ'17O values in the winter (40 ± 15 per meg [± standard deviation]) than in the summer (18 ± 18 per meg). This seasonal precipitation Δ'17O variability likely arises from a combination of sub-cloud evaporation, atmospheric mixing, moisture recycling, sublimation, and/or relative humidity, but the data set is not well suited to quantitatively assess isotopic variability associated with each of these processes. The seasonal Δ'17O pattern, which is absent in d-excess and opposite in sign from δ18O, appears in other data sets globally; it showcases the influence of seasonality on Δ'17O values of precipitation and highlights the need for further systematic studies to understand variation in Δ'17O values of precipitation.
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Primary immunodeficiency disorders (PID) are a group of heterogeneous disorders characterized by recurrent infections, autoimmunity, increased lymphoproliferative disorders and other malignancies. PID is classified into cellular or humoral disorders or a combination of both. We evaluated the clinical differences among adult patients with three variants of PID: common variable immunodeficiency (CVID), idiopathic CD4 lymphopenia (ICL) and combined immunodeficiency (CID). We retrospectively compared demographics, immunological characteristics, clinical presentations and outcomes of CVID, CID and ICL patients followed from 2012 to 2018. In our cohort, we identified 44 adult patients diagnosed with CVID (22), CID (11) and ICL (11). Malignancy was associated with CID, as seven of 11 patients in this group were diagnosed with malignancy compared to CVID (three of 22) or ICL (two of 11) (P = 0·002 and 0·03, respectively). Malignancies were also linked to male gender [odds ratio (OR) = 5, 95% confidence interval (CI) = 1·12-22·18) P = 0·0342] and a low ratio of CD4/CD8 < 0·8 (OR = 5·1, 95% CI = 1·22-21·28, P = 0·025). Among CID and ICL, two of 11 patients died in each group, while no death was documented among CVID group (P = 0·04). Autoimmune manifestations did not differ between groups. Similarly, the rate of infections was similar between groups, although infectious agents vary. CID is associated with a high risk of malignancy compare to CVID or ICL. Among adults with PID, male gender, low CD4 and a CD4/CD8 ratio of < 0·8 may serve as risk factors of concomitant malignancy. Surveillance of lymphocyte subpopulations should be considered for all adults.
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Inmunodeficiencia Variable Común/inmunología , Linfopenia/inmunología , Neoplasias/inmunología , Enfermedades de Inmunodeficiencia Primaria/inmunología , Adulto , Autoinmunidad/inmunología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Fenotipo , Estudios RetrospectivosRESUMEN
Belimumab, an anti-B-lymphocyte stimulator monoclonal antibody, was recently approved for the treatment of systemic lupus erythematosus. Alopecia areata is characterized by an acute immune-mediated hair loss. Herein, we report on three adult systemic lupus erythematosus patients who developed alopecia areata in association with belimumab treatment. Alopecia areata was resolved in all three patients and belimumab was discontinued in two of them. Thus, in the current report, we explore the plausible link between alopecia areata and belimumab.
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Alopecia Areata/inducido químicamente , Anticuerpos Monoclonales Humanizados/efectos adversos , Inmunosupresores/efectos adversos , Lupus Eritematoso Sistémico/tratamiento farmacológico , Corticoesteroides/administración & dosificación , Corticoesteroides/uso terapéutico , Adulto , Alopecia Areata/tratamiento farmacológico , Alopecia Areata/patología , Anticuerpos Monoclonales Humanizados/uso terapéutico , Síndrome Antifosfolípido/diagnóstico , Síndrome Antifosfolípido/tratamiento farmacológico , Femenino , Humanos , Inmunosupresores/uso terapéutico , Inyecciones Intralesiones , Lupus Eritematoso Sistémico/diagnóstico , Masculino , Resultado del Tratamiento , Privación de TratamientoRESUMEN
The river Nile flows across 11 African countries, supporting millions of human livelihoods, and holding globally important biodiversity and endemism yet remains underprotected. No basin-wide spatial conservation planning has been attempted to date, and the importance of coordinated conservation planning for the Nile's biodiversity remains unknown. We address these gaps by creating a basin-wide conservation plan for the Nile's freshwater fish. We identify priority areas for conservation action and compare cross-boundary collaboration scenarios for achieving biodiversity conservation targets, accounting for river connectivity. We found that collaborative conservation efforts are crucial for reducing conservation costs, saving 34% of costs compared to an uncoordinated, business-as-usual scenario. While most Nile basin countries benefit from coordinating conservation planning, costs and benefits are unequally distributed. We identify "hot spots" consistently selected as conservation priority areas across all collaboration scenarios, and provide a framework for improving return on conservation investment for large and complex river systems globally.
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Biodiversidad , Conservación de los Recursos Naturales , Ríos , África , Geografía , HumanosRESUMEN
BACKGROUND: Chronic urticaria (CU) carries many risk factors for osteoporosis, but data on the relationships between CU and osteoporosis are lacking. OBJECTIVES: To evaluate the association between CU and osteoporosis in a large community-based study. METHODS: A nationwide observational longitudinal cohort study was conducted. CU was defined as four pairs of urticaria diagnoses; each pair was recorded within a period of 6 weeks and was registered by physicians in a primary-care setting. Patients with CU and their age- and sex- matched controls were followed for the incidence of osteoporosis and other laboratory data between 2002 and 2017. Data regarding systemic steroid exposure and other relevant risk factors for osteoporosis were obtained. Analyses of risk for osteoporosis were performed in Cox regression models adjusted for age, sex, exposure to systemic corticosteroids, obesity, smoking and hyper- and hypothyroid disease. RESULTS: The study included 11 944 patients with CU and 59 829 controls. During the study's observation period, 1035 (8·7%) patients with CU were diagnosed with osteoporosis, compared with 4046 (6·8%) controls. The adjusted multivariate analysis demonstrated that CU was significantly associated with a higher risk for osteoporosis (hazard ratio 1·23, 95% confidence interval 1·10-1·37, P < 0·001). CONCLUSIONS: CU may impose a risk for osteoporosis. Appropriate targeted screening should be considered.
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Urticaria Crónica/complicaciones , Osteoporosis/epidemiología , Adolescente , Adulto , Estudios de Casos y Controles , Femenino , Humanos , Incidencia , Israel/epidemiología , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Osteoporosis/etiología , Factores de Riesgo , Adulto JovenRESUMEN
The majority of research in the biomedical sciences is carried out with the highest resolution accessible to the scientist, but, in the clinic, cost constraints necessitate the use of low-resolution devices. Here, we compare high- and low-resolution direct mass spectrometry profiling data and propose a simple pre-processing technique that makes high-resolution data suitable for the development of classification and regression techniques applicable to low-resolution data, while retaining high accuracy of analysis. This work demonstrates an approach to de-noising spectra to make the same representation for both high- and low-resolution spectra. This approach uses noise threshold detection based on the Tversky index, which compares spectra with different resolutions, and minimizes the percentage of resolution-specific peaks. The presented method provides an avenue for the development of analytical algorithms using high-resolution mass spectrometry data, while applying these algorithms in the clinic using low-resolution mass spectrometers.
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BACKGROUND: Emerging evidence suggests that chronic urticaria (CU) is associated with chronic, low-grade, inflammatory process. OBJECTIVE: To evaluate the association between CU and metabolic syndrome and its components in a large community-based medical database. METHODS: A cross-sectional study of CU patients and matched controls was performed. CU was defined as eight urticaria diagnoses (with each two diagnoses registered within a period of 6 weeks) from 2002 to 2012. Data regarding the prevalence of metabolic syndrome, its components and possible complications were collected. RESULTS: The study included 11 261 patients with CU and 67 216 controls. In a univariate analysis, CU was significantly associated with higher body mass index (BMI) and a higher prevalence of obesity, diabetes, hyperlipidaemia, hypertension, metabolic syndrome, chronic renal failure and gout. Multivariate analysis demonstrated a significant association between CU and metabolic syndrome (OR = 1.12, 95% CI 1.1-1.2, P < 0.001) and its components - obesity (OR = 1.2, 95% CI 1.1-1.3, P < 0.001), diabetes (OR = 1.08, 95% CI 1.01-1.15, P = 0.001), hyperlipidaemia (OR = 1.2, 95% CI 1.1-1.2, P < 0.001) and hypertension (OR = 1.1, 95% CI 1.1-1.2, P < 0.001). CONCLUSIONS: CU patients may have one or more undiagnosed components of metabolic syndrome despite their young age. Thus, appropriate targeted screening is advised.
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Diabetes Mellitus/epidemiología , Hiperlipidemias/epidemiología , Hipertensión/epidemiología , Síndrome Metabólico/epidemiología , Obesidad/epidemiología , Urticaria/epidemiología , Adulto , Anciano , Índice de Masa Corporal , Estudios de Casos y Controles , Enfermedad Crónica , Comorbilidad , Estudios Transversales , Femenino , Gota/epidemiología , Humanos , Israel/epidemiología , Fallo Renal Crónico/epidemiología , Masculino , Persona de Mediana Edad , PrevalenciaRESUMEN
Hydroxychloroquine (HCQ) is widely used to treat autoimmune/rheumatic diseases such as systemic lupus erythematosus (SLE). The immune modulation effects of HCQ have been highlighted as beneficial for maintaining remission of SLE as well as ameliorating skin, joint and other manifestations. Moreover, HCQ exposure for prolonged periods as well as during pregnancy is considered safe, therefore it is recommended for the vast majority of SLE patients. Although HCQ therapy requires follow-up by a specialist, its most common side effects are mild gastrointestinal disturbances, sensitivity to light and skin rashes. Of these side effects, hypersensitivity skin reactions have been suggested to play a role in reduced compliance to HCQ therapy. In the current study we present a two-stage HCQ desensitization protocol that was successfully implemented among 12 out of 13 patients. We exhibit that prolonged HCQ oral desensitization is an effective method for overcoming mild to moderate late hypersensitivity reactions and thoroughly address possible mechanisms of action.
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Antirreumáticos/administración & dosificación , Antirreumáticos/efectos adversos , Desensibilización Inmunológica/métodos , Erupciones por Medicamentos/prevención & control , Hidroxicloroquina/administración & dosificación , Hidroxicloroquina/efectos adversos , Lupus Eritematoso Sistémico/tratamiento farmacológico , Administración Oral , Adulto , Anciano , Esquema de Medicación , Erupciones por Medicamentos/diagnóstico , Erupciones por Medicamentos/inmunología , Femenino , Humanos , Lupus Eritematoso Sistémico/diagnóstico , Lupus Eritematoso Sistémico/inmunología , Masculino , Persona de Mediana Edad , Factores de Riesgo , Índice de Severidad de la Enfermedad , Factores de Tiempo , Resultado del TratamientoRESUMEN
The autoimmune/inflammatory syndrome induced by adjuvants (ASIA) is an entity that includes different autoimmune conditions observed after exposure to an adjuvant. Patients with undifferentiated connective tissue disease (UCTD) present many signs and symptoms of ASIA, alluding to the idea that an exposure to adjuvants can be a trigger also for UCTD. The aim of this case-control study was to investigate exposure to adjuvants prior to disease onset in patients affected by UCTD. Ninety-two UCTD patients and 92 age- and sex-matched controls with no malignancy, chronic infections, autoimmune disease nor family history of autoimmune diseases were investigated for exposure to adjuvants. An ad hoc-created questionnaire exploring the exposure to vaccinations, foreign materials and environmental and occupational exposures was administered to both cases and controls. Autoantibodies were also analyzed (anti-nuclear, anti-extractable nuclear antigens, anti-double-stranded DNA, anti-cardiolipin, anti-ß2 glycoprotein I). UCTD patients displayed a greater exposure to HBV (p = 0.018) and tetanus toxoid (p < 0.001) vaccinations, metal implants (p < 0.001), cigarette smoking (p = 0.006) and pollution due to metallurgic factories and foundries (p = 0.048) as compared to controls. UCTD patients exposed to major ASIA triggers (vaccinations, silicone implants) (n = 49) presented more frequently with chronic fatigue (p < 0.001), general weakness (p = 0.011), irritable bowel syndrome (p = 0.033) and a family history for autoimmunity (p = 0.018) in comparison to non-exposed UCTDs. ASIA and UCTD can be considered as related entities in the "mosaic of autoimmunity": the genetic predisposition and the environmental exposure to adjuvants elicit a common clinical phenotype characterized by signs and symptoms of systemic autoimmunity.
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Adyuvantes Inmunológicos/efectos adversos , Adyuvantes Farmacéuticos/efectos adversos , Exposición a Riesgos Ambientales/efectos adversos , Enfermedades Indiferenciadas del Tejido Conectivo/etiología , Adulto , Anciano , Estudios de Casos y Controles , Femenino , Humanos , Italia/epidemiología , Masculino , Persona de Mediana Edad , Vacunas contra Papillomavirus/efectos adversos , Prótesis e Implantes/efectos adversos , Siliconas/efectos adversos , Fumar/efectos adversos , Síndrome , Toxoide Tetánico/efectos adversos , Vacunación/efectos adversosRESUMEN
The group of chondrodysplasia with multiple dislocations includes several entities, characterized by short stature, dislocation of large joints, hand and/or vertebral anomalies. Other features, such as epiphyseal or metaphyseal changes, cleft palate, intellectual disability are also often part of the phenotype. In addition, several conditions with overlapping features are related to this group and broaden the spectrum. The majority of these disorders have been linked to pathogenic variants in genes encoding proteins implicated in the synthesis or sulfation of proteoglycans (PG). In a series of 30 patients with multiple dislocations, we have performed exome sequencing and subsequent targeted analysis of 15 genes, implicated in chondrodysplasia with multiple dislocations, and related conditions. We have identified causative pathogenic variants in 60% of patients (18/30); when a clinical diagnosis was suspected, this was molecularly confirmed in 53% of cases. Forty percent of patients remain without molecular etiology. Pathogenic variants in genes implicated in PG synthesis are of major importance in chondrodysplasia with multiple dislocations and related conditions. The combination of hand features, growth failure severity, radiological aspects of long bones and of vertebrae allowed discrimination among the different conditions. We propose key diagnostic clues to the clinician.
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Discapacidad Intelectual/genética , Anomalías Musculoesqueléticas/genética , Osteocondrodisplasias/genética , Adolescente , Adulto , Niño , Preescolar , Femenino , Estudios de Asociación Genética , Humanos , Lactante , Recién Nacido , Discapacidad Intelectual/diagnóstico , Discapacidad Intelectual/diagnóstico por imagen , Discapacidad Intelectual/fisiopatología , Masculino , Anomalías Musculoesqueléticas/diagnóstico , Anomalías Musculoesqueléticas/diagnóstico por imagen , Anomalías Musculoesqueléticas/fisiopatología , Osteocondrodisplasias/diagnóstico , Osteocondrodisplasias/diagnóstico por imagen , Osteocondrodisplasias/fisiopatología , Radiografía , Secuenciación del ExomaRESUMEN
OBJECTIVES: Develop recommendations for women's health issues and family planning in systemic lupus erythematosus (SLE) and/or antiphospholipid syndrome (APS). METHODS: Systematic review of evidence followed by modified Delphi method to compile questions, elicit expert opinions and reach consensus. RESULTS: Family planning should be discussed as early as possible after diagnosis. Most women can have successful pregnancies and measures can be taken to reduce the risks of adverse maternal or fetal outcomes. Risk stratification includes disease activity, autoantibody profile, previous vascular and pregnancy morbidity, hypertension and the use of drugs (emphasis on benefits from hydroxychloroquine and antiplatelets/anticoagulants). Hormonal contraception and menopause replacement therapy can be used in patients with stable/inactive disease and low risk of thrombosis. Fertility preservation with gonadotropin-releasing hormone analogues should be considered prior to the use of alkylating agents. Assisted reproduction techniques can be safely used in patients with stable/inactive disease; patients with positive antiphospholipid antibodies/APS should receive anticoagulation and/or low-dose aspirin. Assessment of disease activity, renal function and serological markers is important for diagnosing disease flares and monitoring for obstetrical adverse outcomes. Fetal monitoring includes Doppler ultrasonography and fetal biometry, particularly in the third trimester, to screen for placental insufficiency and small for gestational age fetuses. Screening for gynaecological malignancies is similar to the general population, with increased vigilance for cervical premalignant lesions if exposed to immunosuppressive drugs. Human papillomavirus immunisation can be used in women with stable/inactive disease. CONCLUSIONS: Recommendations for women's health issues in SLE and/or APS were developed using an evidence-based approach followed by expert consensus.
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Síndrome Antifosfolípido/tratamiento farmacológico , Neoplasias de los Genitales Femeninos/diagnóstico , Lupus Eritematoso Sistémico/tratamiento farmacológico , Complicaciones del Embarazo/tratamiento farmacológico , Anticonceptivos Hormonales Orales/uso terapéutico , Técnica Delphi , Detección Precoz del Cáncer , Terapia de Reemplazo de Estrógeno , Servicios de Planificación Familiar , Femenino , Preservación de la Fertilidad , Monitoreo Fetal , Humanos , Menopausia , Atención Preconceptiva , Embarazo , Técnicas Reproductivas Asistidas , Medición de RiesgoRESUMEN
BACKGROUND/OBJECTIVES: Hyponatremia is a risk factor for mortality in hemodialysis (HD) patients. It is not well known to which extent the comorbidities, malnutrition, fluid status imbalance and inflammation are related to hyponatremia and affect outcomes. SUBJECTS/METHODS: We studied 8883 patients from the European subset of the international MONitoring Dialysis Outcomes initiative. Nutritional and fluid statuses were assessed by bioimpedance spectroscopy. Fluid depletion was defined as overhydration⩽-1.1 l and fluid overload as overhydration>+1.1 l, respectively. Malnutrition was defined as a lean tissue index below the 10th percentile of age- and gender-matched healthy controls. Hyponatremia and inflammation were defined as serum sodium levels <135 mEq/l and C-reactive protein levels>6.0 mg/l, respectively. We used logistic regression to test for predictors of hyponatremia and Cox proportional hazards analysis to assess the association with all-cause mortality. RESULTS: Hyponatremia was predicted by the presence of malnutrition (odds ratio (OR)=1.49 (95% confidence interval (CI)=1.30-1.70), inflammation (OR=1.44 (95% CI=1.26-1.64)) and fluid overload ((>+1.1 l to +2.5 l) OR=0.73 (95% CI=0.62-0.85)) but not by fluid depletion (OR=1.34 (95% CI=0.92-1.96)). Malnutrition, inflammation, fluid overload, fluid depletion and hyponatremia (hazard ratio=1.70 (95% CI=1.46-1.99)) were independent predictors for all-cause mortality. CONCLUSIONS: In HD patients, hyponatremia is associated with malnutrition, inflammation and fluid overload. Hyponatremia maintained predictive for all-cause mortality after adjustment for malnutrition, inflammation and fluid status abnormalities. The presence of hyponatremia may assist in identifying HD patients at increased risk of death.
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Hiponatremia/etiología , Inflamación/complicaciones , Desnutrición/complicaciones , Diálisis Renal/efectos adversos , Sodio/sangre , Desequilibrio Hidroelectrolítico , Anciano , Proteína C-Reactiva/metabolismo , Causas de Muerte , Europa (Continente) , Femenino , Humanos , Hiponatremia/sangre , Hiponatremia/mortalidad , Inflamación/sangre , Inflamación/mortalidad , Modelos Logísticos , Masculino , Desnutrición/mortalidad , Persona de Mediana Edad , Estado Nutricional , Oportunidad Relativa , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Diálisis Renal/mortalidad , Insuficiencia Renal/terapia , Factores de Riesgo , Albúmina Sérica/metabolismoRESUMEN
A recent study from the United Kingdom indicates an association between pre hemodialysis (HD) serum sodium (SNa(+)) and systolic and diastolic blood pressure (SBP and DBP) in chronic HD patients. We extend this analysis to an international cohort of incident HD patients. The Monitoring Dialysis Outcomes initiative encompasses patients from 41 countries. Over 2 years monthly pre-HD SNa(+) levels were used as predictors of pre-HD SBP and DBP in a linear mixed model (LMM) adjusted for age, gender, interdialytic weight gain, diabetes, serum albumin and calcium. Similar models were constructed with DBP as outcome. Analyses were carried out stratified by continent (North and South America; Europe and Asia). LMMs were also constructed for the entire observation period of 2 years, and separately the first and the second year after HD initiation. We studied 17 050 incident patients and found SNa(+) to have a significant slope estimate in the LMM predicting pre-HD SBP and DBP (ranging from 0.22 to 0.29 and 0.10 to 0.21 mm Hg per mEq l(-1), respectively, between the continents). The findings were similar in subsets of SBP and SNa(+) tertiles, and separately analyzed for the first and second year. Our analysis shows an independent association between SNa, SBP and DBP in a large intercontinental database, indicating that this relation is a profound biological phenomenon in incident and prevalent HD patients, generalizable to an international level and independent of SBP and DBP magnitude.
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Presión Sanguínea , Fallo Renal Crónico/terapia , Diálisis Renal , Sodio/sangre , Adulto , Anciano , Asia/epidemiología , Biomarcadores/sangre , Europa (Continente)/epidemiología , Femenino , Humanos , Incidencia , Fallo Renal Crónico/sangre , Fallo Renal Crónico/epidemiología , Fallo Renal Crónico/fisiopatología , Estudios Longitudinales , Masculino , Persona de Mediana Edad , América del Norte/epidemiología , Prevalencia , Estudios Retrospectivos , América del Sur/epidemiología , Factores de Tiempo , Resultado del TratamientoRESUMEN
The study aims to test whether impaired conduction velocities following optic neuritis (ON) serve as a limiting factor on various temporal, as compared to static, aspects of vision. Critical Flicker fusion frequency (CFFF), two motion perception tasks (object and number-from-motion extraction tasks), high and low contrast acuities, and visual evoked potentials (VEPs) were assessed in 23 ON patients. Strong correlations were found between the various dynamic visual function scores. Furthermore, regression models revealed that each of the dynamic visual functions significantly predicted VEP latencies. These findings were specific to patients' affected eyes and were not evident for static visual functions. Fellow eyes' VEP latencies were best predicted by the VEP latencies of the affected eyes. The similar impact of VEP latencies on various dynamic visual functions suggests conduction velocity to be the common limiting factor for temporal-related visual perceptual abilities. The specificity of these findings to the patients' affected eyes and to dynamic visual functions highlights the precision of dynamic visual functions for identifying demyelinative attack. Prolonged VEP latencies in the fellow eyes seem to stem from different patho-physiological processes. The hypothesis that inter-eye synchronization in conduction latencies is important to accomplish visual processing (binocular vision) is further discussed.
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Potenciales Evocados Visuales/fisiología , Percepción de Movimiento/fisiología , Neuritis Óptica/diagnóstico , Tiempo de Reacción/fisiología , Adulto , Estudios de Cohortes , Enfermedades Desmielinizantes/diagnóstico , Enfermedades Desmielinizantes/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neuritis Óptica/fisiopatología , Percepción Visual/fisiologíaAsunto(s)
Arachis/efectos adversos , Desensibilización Inmunológica , Hipersensibilidad al Cacahuete/prevención & control , Alérgenos/administración & dosificación , Alérgenos/inmunología , Antígenos de Plantas/administración & dosificación , Antígenos de Plantas/inmunología , Humanos , Lactante , Guías de Práctica Clínica como Asunto , Factores de TiempoRESUMEN
BACKGROUND: Neuronal loss following damage is often greater than expected from the severity of injury to the nerve itself. The visual pathways, which comprise a well-defined system, and optic neuritis (ON), which is usually a discrete event, make a fine model to study this phenomenon. OBJECTIVE: Understand the effect of focal optic nerve demyelination on neighboring white matter. METHODS: Diffusion tensor imaging and probabilistic tractography were used to identify and characterize the optic tracts and radiations of 17 ON and matched controls. Data were correlated with retinal nerve fiber layer (RNFL) thickness. RESULTS: Patients' optic tracts exhibited reduced axial diffusivity, which correlated with RNFL thickness values. Patients' optic radiations demonstrated intact axial diffusivity but reduced fractional anisotropy and elevated radial diffusivity, which could be explained by intra-bundle lesions. No correlations were found between diffusivity measurements in patients' optic tracts and radiations; or between RNFL thickness and optic radiations' diffusivity. CONCLUSIONS: Following ON, chronic axonal loss develops distally in the optic tracts, demonstrating Wallerian degeneration. Degeneration did not proceed to the optic radiations, opposing anterograde trans-neuronal changes. DTI in ON provides fine in-vivo human model for studying histological abnormalities in normal appearing white matter, localized in close proximity to damaged bundle.
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Enfermedades Desmielinizantes/patología , Neuritis Óptica/patología , Sustancia Blanca/patología , Adulto , Axones/patología , Estudios Transversales , Imagen de Difusión Tensora , Femenino , Humanos , Masculino , Persona de Mediana Edad , Nervio Óptico/patología , Sinapsis/patología , Degeneración Walleriana/patología , Adulto JovenRESUMEN
PURPOSE: Minimal invasion computer-assisted neurosurgical procedures with various tool insertions into the brain may carry hemorrhagic risks and neurological deficits. The goal of this study is to investigate the role of computer-based surgical trajectory planning tools in improving the potential safety of image-based stereotactic neurosurgery. METHODS: Multi-sequence MRI studies of eight patients who underwent image-guided neurosurgery were retrospectively processed to extract anatomical structures-head surface, ventricles, blood vessels, white matter fibers tractography, and fMRI data of motor, sensory, speech, and visual areas. An experienced neurosurgeon selected one target for each patient. Five neurosurgeons planned a surgical trajectory for each patient using three planning methods: (1) conventional; (2) visualization, in which scans are augmented with overlays of anatomical structures and functional areas; and (3) automatic, in which three surgical trajectories with the lowest expected risk score are automatically computed. For each surgeon, target, and method, we recorded the entry point and its surgical trajectory and computed its expected risk score and its minimum distance from the key structures. RESULTS: A total of 120 surgical trajectories were collected (5 surgeons, 8 targets, 3 methods). The surgical trajectories expected risk scores improved by 76% ([Formula: see text], two-sample student's t test); the average distance of a trajectory from nearby blood vessels increased by 1.6 mm ([Formula: see text]) from 0.6 to 2.2 mm (243%). The initial surgical trajectories were changed in 85% of the cases based on the expected risk score and the trajectory distance from blood vessels. CONCLUSIONS: Computer-based patient-specific preoperative planning of surgical trajectories that minimize the expected risk of vascular and neurological damage due to incorrect tool placement is a promising technique that yields consistent improvements.