Mercury Exposure in a Riverside Amazon Population, Brazil: A Study of the Ototoxicity of Methylmercury

Introduction Mercury poisoning causes hearing loss in humans and animals. Acute and long-term exposures produce irreversible peripheral and central auditory system damage, and mercury in its various forms of presentation in the environment is ototoxic. Objective We investigated the otoacoustic emissions responses in a riverside population exposed to environmental mercury by analyzing the inhibitory effect of the medial olivocochlear system (MOCS) on transient otoacoustic emissions (TEOAE). Methods The purpose of the research was to evaluate the entire community independently of variables of sex and age. All of the participants were born and lived in a riverside community. After otolaryngologic evaluation, participants were received tympanometry, evaluation of contralateral acoustic reflexes, pure tone audiometry, and recording of TEOAEs with nonlinear click stimulation. Hair samples were collect to measure mercury levels. Results There was no significant correlation between the inhibitory effect of the MOCS, age, and the level of mercury in the hair. Conclusions The pathophysiological effects of chronic exposure may be subtle and nonspecific and can have a long period of latency; therefore, it will be important to monitor the effects of mercury exposure in the central auditory system of the Amazon population over time. Longitudinal studies should be performed to determine whether the inhibitory effect of the MOCS on otoacoustic emissions can be an evaluation method and diagnostic tool in populations exposed to mercury. .

Frecuencia de alelos HLA de clase I y II en una cohorte de pacientes con espondiloartritis provenientes del noroccidente colombiano / Frequency of HLA alleles class I and II in a cohort of northwestern Colombian patients with spondyloarthritis

Introducción. Las espondiloartritis son enfermedades reumatológicas crónicas que afectan el esqueleto axial y las articulaciones periféricas, con varias manifestaciones extraarticulares. La asociación con el HLA-B27 sigue siendo uno de los vínculos más fuertes conocidos entre estas entidades y el complejo mayor de histocompatibilidad; sin embargo, la distribución mundial del HLA-B27 varía considerablemente y se han descrito asociaciones con genes no HLA-B27. Objetivo. Conocer la frecuencia de alelos HLA de clase I y II en pacientes con espondiloartritis provenientes del noroccidente colombiano y su frecuencia en las manifestaciones clínicas y radiológicas específicas. Materiales y métodos. Se condujo un estudio descriptivo, observacional, de corte transversal, retrospectivo y prospectivo entre 2005 y 2008 de 56 pacientes colombianos con espondiloartritis. Se identificaron los alelos correspondientes a los loci HLA de clase I y II (HLA-B, HLADQB1 y HLADRB). Se analizó su frecuencia con las manifestaciones clínicas axiales, periféricas, extraarticulares y radiológicas. Resultados. Se encontró una baja frecuencia de HLA-B27 en la población total (50 %), aunque fue el alelo más frecuente, junto con HLA-DRB4*01 (35,7 %) y HLA-DQB1*0501 (28,6 %), en todos los pacientes en general y en cada una de las manifestaciones clínicas y radiológicas. Se resalta la alta frecuencia de HLA-B27 y HLA-DRB4*01 (64,3 %) en pacientes con dactilitis, hallazgo novedoso sin previa descripción. Conclusión. Los alelos HLA-B27, HLA-DRB4*01 y HLA-DQB1*0501 fueron frecuentes en los diferentes subtipos de espondiloartritis y en las manifestaciones clínicas axiales, periféricas y extraarticulares específicas, además de la sacroiliítis radiológica.

Introduction. Spondyloarthritis is a chronic rheumatic disease that affect the axial skeleton and peripheral joints, along with several extra-articular manifestations. The association with HLA-B27 remains one of the strongest known links between these entities and the major histocompatibility complex. However, the global distribution of HLA-B27 varies considerably and furthermore, associations with non-HLA-B27 genes have been described. Objective. The frequency of HLA class I and II was determined in a population of patients with spondyloarthritis with respect to detection in the clinical setting and by radiology. Materials and methods. A descriptive, observational, cross-sectional, retrospective and prospective study was conducted in 56 patients from northwestern Colombia. Each was diagnosed with spondyloarthritis between 2005 and 2008. In each case, alleles were identified for the loci HLA class I and II (HLA-B; HLADQB1 and HLADRB). The frequency of these alleles in the axial, peripheral, extraarticular and radiological manifestations. Results.The frequency of HLA-B27 was 50% overall, and it was the most frequent allele. The two other alleles were HLA.DRB4*01 at 35.7% and HLA-DQB1*0501 at 28.6%, as detected in each of the clinical and radiological manifestations. A high frequency of HLA-B27 and HLA-DRB4*01 (64.3%) was noted in patients with dactylitis. Conclusion. The alleles HLA-B27, HLA-DRB4*01 and HLA-DQB1*0501 were common in the different subtypes of spondyloarthritis and were frequent in the specific clinical axial, peripheral and extraarticular clinical manifestations, as well as radiological sacroiliitis.

Patogenia de las artropatías seronegativas / Pathogenesis of seronegative arthropathies

Las espondiloartropatías son un grupo de trastornos inflamatorios crónicos que afectan principalmente el esqueleto axial y las articulaciones; se caracterizan por tener factor reumatoide negativo, además de asociarse, frecuentemente, a HLA B27. Muchas veces se acompañan de manifestaciones extraarticulares. Este grupo esta compuesto por cinco patologías: la espondilitis anquilosante, la artritis psoriática, la espondiloartropatía con enfermedad inflamatoria intestinal, la artritis reactiva, incluyendo la enfermedad de Reiter, y la espondiloartropatía indiferenciada. Estas enfermedades son infrecuentes, estimándose una incidencia de 0,2 a un 1 por ciento; su importancia radica en que con frecuencia la aparición es a temprana edad, pudiendo causar gran invalidez. Hasta el momento se desconoce, con certeza, la patogenia de estas enfermedades, planteándose varias hipótesis, basadas principalmente en la participación de la molécula de histocompatibilidad ya mencionada. Es necesario distinguir entre las distintas patologías que conforman este grupo, ya que muchas veces el tratamiento y el pronóstico son diferentes.

Spondyloarthropathies are a group of chronic inflammatory disorders affecting primarily the axial skeleton and joints; they are characterized by a negative rheumatoid factor, and frequently associated with HLA B27. They are often accompanied by extra-articular manifestations. This group is composed of five diseases: ankylosing spondylitis, psoriatic arthritis, spondylarthropathy with Seronegativasinflammatory bowel disease, reactive arthritis, including Reiter’s disease, and undifferentiated spondylarthropathy. These diseases are rare, with an estimated incidence of 0.2 to 1 percent; importance lies in that often the onset is at an early age and can cause major disability. So far, the pathogenesis of these diseases is not known with certainty, though several hypotheses have been raised, mainly based on the involvement of the histocompatibility molecule mentioned above. It is necessary to distinguish between the different disorders that make up this group, because treatment and prognosis of each are different.