Early-onset cerebellar ataxia in a patient with CMT2A2.

A 9-yr 8-mo-old right-handed female presented with a history of gait difficulties, which first became apparent at age 9 mo of age, along with slurred speech and hand tremors while holding a tray. Her past medical history was significant for global developmental delay, and she was attending fourth grade special education classes. On examination, she had an ataxic gait, dysarthria, absent deep tendon reflexes, and flexor plantar responses. There were no signs of optic atrophy or hearing loss. Nerve conduction studies were consistent with an axonal neuropathy. A fascicular sural nerve biopsy showed a marked decrease of myelinated fibers larger than 6 µm in diameter as compared with an age-matched control. By electron microscopy, clusters of degenerating axonal mitochondria in both myelinated and unmyelinated fibers were frequently found. Whole-exome sequencing revealed a heterozygous c.314C > T (p.Thr105Met) missense variant in MFN2 in the patient but not in her mother. The father was unavailable for testing. The phenotypes with MFN2 variants can be quite variable, including intellectual disability, optic atrophy, auditory impairment, spinal atrophy with or without hydromyelia, and hydrocephalus. We report here that early onset ataxia with intellectual disability can also be associated with MFN2-related Charcot-Marie-Tooth, Type 2A2A diagnosis, the most common type of autosomal dominant axonal neuropathy.

Nanotechnology: A reality for diagnosis of HCV infectious disease.

Hepatitis C virus (HCV) is the primary etiologic agent of liver cirrhosis or hepatocellular carcinoma. HCV elevated infection rates are mostly due to the lack of an accurate and accessible screening and diagnosis, especially in low- and middle-income countries. Conventional HCV diagnostic algorithm consists of a serological test followed by a nucleic acid test. This sequence of tests is time consuming and not affordable for low-resource settings. Nanotechnology have introduced new promising tests for the diagnose of infectious diseases. Based on the employment of nanoparticles and other nanomaterials which lead to highly sensitive and specific nanoscale tests, most of them target pathogen genome. Implementation of nanoscale tests, which are affordable, portable and easy to use by non-specialized personal, would improve HCV diagnosis algorithm. In this review, we have summed up the current emerging nanotechnology tools, which will improve actual screening and treatment programs, and help to reach HCV elimination proposal.

HIV-1 Nef Targets HDAC6 to Assure Viral Production and Virus Infection.

HIV Nef is a central auxiliary protein in HIV infection and pathogenesis. Our results indicate that HDAC6 promotes the aggresome/autophagic degradation of the viral polyprotein Pr55Gag to inhibit HIV-1 production. Nef counteracts this antiviral activity of HDAC6 by inducing its degradation and subsequently stabilizing Pr55Gag and Vif viral proteins. Nef appears to neutralize HDAC6 by an acidic/endosomal-lysosomal processing and does not need the downregulation function, since data obtained with the non-associated cell-surface Nef-G2A mutant - the cytoplasmic location of HDAC6 - together with studies with chemical inhibitors and other Nef mutants, point to this direction. Hence, the polyproline rich region P72xxP75 (69-77 aa) and the di-Leucin motif in the Nef-ExxxLL160-165 sequence of Nef, appear to be responsible for HDAC6 clearance and, therefore, required for this novel Nef proviral function. Nef and Nef-G2A co-immunoprecipitate with HDAC6, whereas the Nef-PPAA mutant showed a reduced interaction with the anti-HIV-1 enzyme. Thus, the P72xxP75 motif appears to be responsible, directly or indirectly, for the interaction of Nef with HDAC6. Remarkably, by neutralizing HDAC6, Nef assures Pr55Gag location and aggregation at plasma membrane, as observed by TIRFM, promotes viral egress, and enhances the infectivity of viral particles. Consequently, our results suggest that HDAC6 acts as an anti-HIV-1 restriction factor, limiting viral production and infection by targeting Pr55Gag and Vif. This function is counteracted by functional HIV-1 Nef, in order to assure viral production and infection capacities. The interplay between HIV-1 Nef and cellular HDAC6 may determine viral infection and pathogenesis, representing both molecules as key targets to battling HIV.

VAC14 syndrome in two siblings with retinitis pigmentosa and neurodegeneration with brain iron accumulation.

Whole-exome sequencing was used to identify the genetic etiology of a rapidly progressing neurological disease present in two of six siblings with early childhood onset of severe progressive spastic paraparesis and learning disabilities. A homozygous mutation (c.2005G>T, p, V669L) was found in VAC14, and the clinical phenotype is consistent with the recently described VAC14-related striatonigral degeneration, childhood-onset syndrome (SNDC) (MIM#617054). However, the phenotype includes a distinct clinical presentation of retinitis pigmentosa (RP), which has not previously been reported in association with VAC14 mutations. Brain magnetic resonance imaging (MRI) revealed abnormal magnetic susceptibility in the globus pallidus, which can be seen in neurodegeneration with brain iron accumulation (NBIA). RP is a group of inherited retinal diseases with phenotypic/genetic heterogeneity, and the pathophysiologic basis of RP is not completely understood but is thought to be due to a primary retinal photoreceptor cell degenerative process. Most cases of RP are seen in isolation (nonsyndromic); this is a report of RP in two siblings with VAC14-associated syndrome, and it is suggested that a connection between RP and VAC14-associated syndrome should be explored in future studies.

[Spirometric caracterization of cystic fibrosis patients]. / Caracterización espirométrica de pacientes con fibrosis quística.

INTRODUCTION: The prognosis of patients with cystic fibrosis (CF) has remarkably improved. The as sessment of the disease progression is based on the measurement of the FEV1 (Forced Expiratory Volume in one second). OBJECTIVES: 1. To describe forced expiratory flows and volumes and com pare their interpretation according to different reference standards (Knudson, Gutiérrez, and multi ethnic GLI); 2. To describe bronchodilator response. PATIENTS AND METHOD: The medical records and spirometries of all patients with CF controlled at the Dr. Sotero del Rio Hospital were reviewed. Demographic background, sweat test results, genetic study , and bacteriological study were obtained. In addition, Forced Vital Capacity (FVC) was recorded as well as FEV1 and FEV1/FVC ratio. Re sults: Data from 14 patients, were analyzed, seven males, aged 6-24 years, median 15 years, median BMI 18.15 (range 14.6-23.3), median sweat chloride test 76 mEq/l (range 50,2-119 mEq/l), seven patients with at least one F508del mutation. Using multi-ethnic and Gutierrez predictive formulas, lung function involvement occurred previously in relation to the use of Knudson equations. None of the patients had a significant bronchodilator response. CONCLUSION: The group of patients descri bed mostly presents functional respiratory involvement and had no bronchodilator response. The interpretation of functional respiratory involvement varies according to the theoretical values used.

Caracterización espirométrica de pacientes con fibrosis quística / Spirometric caracterization of cystic fibrosis patients

INTRODUCCIÓN: El pronóstico de los pacientes con fibrosis quística (FQ) ha mejorado en forma notable. La evaluación de la progresión de la enfermedad se basa en la medición del Volumen Espirado al primer segundo (VEF1). OBJETIVOS: 1. Describir volúmenes y flujos espiratorios forzados y comparar su interpretación según diferentes patrones de referencia (Knudson, multiétnicas Global Lung Initiative, Gutiérrez); 2. Comparar evolución de VEF1 según diferentes patrones de referencia; 3. Describir respuesta a broncodilatador. PACIENTES Y MÉTODO: Estudio retrospectivo de fichas clínicas y espirometrías de pacientes con FQ controlados en Hospital Dr. Sótero del Río. Se obtuvo antecedentes demográficos, resultados de prueba de sudor, estudio genético, estudio bacteriológico. Se evaluó respuesta a broncodilatador (salbutamol 400 ugr), considerando significativo un aumento en 12% en el VEF1. El valor de cloro en sudor se obtuvo mediante método de Gibson y Cooke. Se registraron: Capacidad Vital Forzada (CVF), Volumen Espirado al primer segundo (VEF1) y relación VEF1/CVF. Para graficar la progresión del VEF1 en el tiempo y las curvas teóricas de GLI, Knudson y Gutiérrez, se utilizó el software de libre distribución R versión 3.3.1. RESULTADOS: Se incluyeron 14 pacientes, 7 varones, edad entre 6 y 24 años, mediana 15 años, me diana índice de masa corporal (IMC) 18,15 (rango 14,6-23,3), mediana cloro en sudor 76 mEq/l (rango 50,2- 119), 7 pacientes con al menos 1 mutación F508del. Al utilizar fórmulas predictivas multiétnicas y de Gutiérrez, el compromiso de la función pulmonar ocurría con anterioridad en relación al uso de ecuaciones de Knudson. Ninguno de los pacientes presentó respuesta significativa a broncodilatador. CONCLUSIÓN: El grupo de pacientes descritos presenta en su mayoría compromiso funcional respiratorio y no tiene respuesta a broncodilatador. La interpretación del compromiso funcional respiratorio varía según los valores teóricos utilizados.

INTRODUCTION: The prognosis of patients with cystic fibrosis (CF) has remarkably improved. The as sessment of the disease progression is based on the measurement of the FEV1 (Forced Expiratory Volume in one second). OBJECTIVES: 1. To describe forced expiratory flows and volumes and com pare their interpretation according to different reference standards (Knudson, Gutiérrez, and multi ethnic GLI); 2. To describe bronchodilator response. Patients and Method: The medical records and spirometries of all patients with CF controlled at the Dr. Sotero del Rio Hospital were reviewed. Demographic background, sweat test results, genetic study , and bacteriological study were obtained. In addition, Forced Vital Capacity (FVC) was recorded as well as FEV1 and FEV1/FVC ratio. RESULTS: Data from 14 patients, were analyzed, seven males, aged 6-24 years, median 15 years, median BMI 18.15 (range 14.6-23.3), median sweat chloride test 76 mEq/l (range 50,2-119 mEq/l), seven patients with at least one F508del mutation. Using multi-ethnic and Gutierrez predictive formulas, lung function involvement occurred previously in relation to the use of Knudson equations. None of the patients had a significant bronchodilator response. CONCLUSION: The group of patients descri bed mostly presents functional respiratory involvement and had no bronchodilator response. The interpretation of functional respiratory involvement varies according to the theoretical values used.

CD2v Interacts with Adaptor Protein AP-1 during African Swine Fever Infection.

African swine fever virus (ASFV) CD2v protein is believed to be involved in virulence enhancement, viral hemadsorption, and pathogenesis, although the molecular mechanisms of the function of this viral protein are still not fully understood. Here we describe that CD2v localized around viral factories during ASFV infection, suggesting a role in the generation and/or dynamics of these viral structures and hence in disturbing cellular traffic. We show that CD2v targeted the regulatory trans-Golgi network (TGN) protein complex AP-1, a key element in cellular traffic. This interaction was disrupted by brefeldin A even though the location of CD2v around the viral factory remained unchanged. CD2v-AP-1 binding was independent of CD2v glycosylation and occurred on the carboxy-terminal part of CD2v, where a canonical di-Leu motif previously reported to mediate AP-1 binding in eukaryotic cells, was identified. This motif was shown to be functionally interchangeable with the di-Leu motif present in HIV-Nef protein in an AP-1 binding assay. However, we demonstrated that it was not involved either in CD2v cellular distribution or in CD2v-AP-1 binding. Taken together, these findings shed light on CD2v function during ASFV infection by identifying AP-1 as a cellular factor targeted by CD2v and hence elucidate the cellular pathways used by the virus to enhance infectivity.

Biopsy in a patient with PMP22 exon 2 mutation recapitulates pathology of Trembler-J mouse.

We describe a patient with a longstanding history of hypertrophic neuropathy of Dejerine-Sottas type, ultimately diagnosed with CMT1E disease due to a new p.Leu18Arg missense mutation in the first transmembrane domain of the PMP22 gene. The patient never walked independently and was wheelchair bound by age 18 years. Her parents and son were unaffected. Her peroneal muscular atrophy syndrome presented with scoliosis, bilateral hearing loss, pes planus, distal sensory loss and generalized areflexia. A nerve biopsy at age 26 years showed nerve hypertrophy, myelin uncompaction, defects in mesaxon formation, Schwann cells with irregular outline, axons incompletely surrounded by Schwann cell processes and very short internodes interspersed with denuded axons. Large, mostly denervated, onion bulb formations were also prominent. These findings indicate that demyelination continues undeterred in the advanced stages of the disease and is followed by remyelination attempts that recapitulate the early defects in Schwann cell/axon interaction seen in the Trembler-J mouse, which carries a mutation in the same transmembrane domain.

Formin INF2 regulates MAL-mediated transport of Lck to the plasma membrane of human T lymphocytes.

Expression of the src-family kinase lymphocyte-specific protein tyrosine kinase (Lck) at the plasma membrane is essential for it to fulfill its pivotal role in signal transduction in T lymphocytes. MAL, an integral membrane protein expressed in specific types of lymphoma, has been shown to play an important role in targeting Lck to the plasma membrane. Here we report that MAL interacts with Inverted Formin2 (INF2), a formin with the atypical property of promoting not only actin polymerization but also its depolymerization. In Jurkat T cells, INF2 colocalizes with MAL at the cell periphery and pericentriolar endosomes and along microtubules. Videomicroscopic analysis revealed that the MAL(+) vesicles transporting Lck to the plasma membrane move along microtubule tracks. Knockdown of INF2 greatly reduced the formation of MAL(+) transport vesicles and the levels of Lck at the plasma membrane and impaired formation of a normal immunologic synapse. The actin polymerization and depolymerization activities of INF2 were both required for efficient Lck targeting. Cdc42 and Rac1, which bind to INF2, regulate Lck transport in both Jurkat and primary human T cells. Thus, INF2 collaborates with MAL in the formation of specific carriers for targeting Lck to the plasma membrane in a process regulated by Cdc42 and Rac1.

The formin INF2 regulates basolateral-to-apical transcytosis and lumen formation in association with Cdc42 and MAL2.

Transcytosis is a widespread pathway for apical targeting in epithelial cells. MAL2, an essential protein of the machinery for apical transcytosis, functions by shuttling in vesicular carriers between the apical zone and the cell periphery. We have identified INF2, an atypical formin with actin polymerization and depolymerization activities, which is a binding partner of MAL2. MAL2-positive vesicular carriers associate with short actin filaments during transcytosis in a process requiring INF2. INF2 binds Cdc42 in a GTP-loaded-dependent manner. Cdc42 and INF2 regulate MAL2 dynamics and are necessary for apical transcytosis and the formation of lateral lumens in hepatoma HepG2 cells. INF2 and MAL2 are also essential for the formation of the central lumen in organotypic cultures of epithelial MDCK cells. Our results reveal a functional mechanism whereby Cdc42, INF2, and MAL2 are sequentially ordered in a pathway dedicated to the regulation of transcytosis and lumen formation.

Síndromes neurocutáneos en la consulta neurológica: serie de casos / Neurocutaneous syndromes in the neurological consultation: case series

Los síndromes neurocutáneos son trastornos genéticos que afectan simultáneamente a la piel, sus anexos y al sistema nervioso. Mediante un esfuerzo colaborativo, se incluyó a pacientes con síndrome neurocutáneo vistos consecutivamente en clínicas tanto del Hospital Escuela como en dos clínicas privadas de Tegucigalpa del 2000 al 2007. Se realizó examen clínico/neurológico/dermatológico, árbol genealógico, exámenes de gabinete y biopsia de lesiones no bien definidas clínicamente o sospechosas de malignidad. Se clasificaron los casos deacuerdo a los criterios de las sociedades internacionales de dermatología. Se identificaron 37 casos, 64% del sexo femenino, 65% menores de 30 años. El síndrome más frecuente en el grupo fue la neurofibromatosis tipo I (44%), la Esclerosis Tuberosa (17%) y el síndrome de Sturge Weber (14%). Las principales consecuencias neurológicas fueron cefalea (22%), epilepsia (22%), déficit motor (13%) y retraso psicomotor (19%). La frecuencia y perfil de los SN encontrados fue similar a lo reportado en la literatura...

Caso clínico-radiológico: quilotorax / Radiological diagnosis of chylothorax

Se presenta el caso clínico de una paciente de 10 años que debutó con derrame pleural masivo con características de quilotórax cuya causa fue secundaria a un linfoma linfoblástico de células T. El quilotórax secundario se trató con manejo conservador consistente en dieta baja en grasas y drenaje pleural en un primer momento y posteriormente -ya teniéndose el diagnóstico establecido- sólo con dieta baja en grasa, presentando una evolución clínica satisfactoria y sin recaídas posteriores. Se discute la etiología del quilotórax, dentro de las cuales se encuentra el linfoma no Hodgkin postulándose como causa la obstrucción del conducto torácico por las masas tumorales. Se revisa el diagnóstico y manejo actual del quilotórax mostrando alguna evidencia del buen resultado del manejo conservador con éxito cercano al 80 por ciento durante las primeras 4 semanas. En los últimos años el uso del análogo de somatostatina, octeotride, con resultados promisorios, está sustentado por series clínicas pequeñas que requieren mayor evaluación antes de una recomendación.

Spastic paraplegia type 2 associated with axonal neuropathy and apparent PLP1 position effect.

OBJECTIVE: To report an association between spastic paraplegia type 2 with axonal peripheral neuropathy and apparent proteolipid protein gene (PLP1) silencing in a family. METHODS: Pulsed-field gel electrophoresis, custom array comparative genomic hybridization, and semi-quantitative multiplex polymerase chain reaction analyses were used to examine the PLP1 genomic region. RESULTS: Electrodiagnostic studies and a sural nerve biopsy showed features of a dystrophic axonal neuropathy. Molecular studies identified a small duplication downstream of PLP1. INTERPRETATION: We propose the duplication to result in PLP1 gene silencing by virtue of a position effect. Our observations suggest that genomic rearrangements that do not include PLP1 coding sequences should be considered as yet another potential mutational mechanism underlying PLP1-related dysmyelinating disorders.

Nef-induced alteration of the early/recycling endosomal compartment correlates with enhancement of HIV-1 infectivity.

human immunodeficiency virus type 1 (HIV-1) Nef interacts with the clathrin-associated AP-1 and AP-3 adaptor complexes, stabilizing their association with endosomal membranes. These findings led us to hypothesize a general impact of this viral protein on the endosomal system. Here, we have shown that Nef specifically disturbs the morphology of the early/recycling compartment, inducing a redistribution of early endosomal markers and a shortening of the tubular recycling endosomal structures. Furthermore, Nef modulates the trafficking of the transferrin receptor (TfR), the prototypical recycling surface protein, indicating that it also disturbs the function of this compartment. Nef reduces the rate of recycling of TfR to the plasma membrane, causing TfR to accumulate in early endosomes and reducing its expression at the cell surface. These effects depend on the leucine-based motif of Nef, which is required for the membrane stabilization of AP-1 and AP-3 complexes. Since we show that this motif is also required for the full infectivity of HIV-1 virions, these results indicate that the positive influence of Nef on viral infectivity may be related to its general effects on early/recycling endosomal compartments.

Aplicaciones médicas de los descubrimientos genómicos / Medical applications of genome discovery

The discovery of the complete base sequence of human genome unveils several perspectives to understand human diseases and develop new therapies. Human genome contains approximately 39,000 genes of which 26,000 code specific proteins that have been identified. There are approximately 1,500 diseases with identified molecular disturbances. Genes can modify signs and symptoms of common diseases. Thus, there are no pure monogenic diseases. Chronic diseases of adults are complex and dependent on multiple factors. Several genes that predispose to chronic degenerative diseases have been identified. This is revealing the complex nature and the interaction of these ailments with the environment. The discovery of bacterial and viral genomic sequences will allow the manufacturing of new vaccines and specific molecular antimicrobials. The new pharmacogenomics will devise treatments for each subject according to her specific genomic profile. The new applications of genomic technology is creating new paradigms in biomedical research such as functional genomics, proteonomics, epigenetic regulation. Gene diagnosis and therapy will considerably improve the future of medicine

Historia de la obra científica de Eduardo Cruz-Coke Lassabe / The scientific work of Eduardo Cruz-Coke Lassabe, MD

Background: Eduardo Cruz Coke M.D., (1899-1974) was one of the precursors and pioneers of biomedical research in Chile, as professor of Physiological and Pathological Chemistry at the University of Chile, from 1925 to 1962. He was a disciple of Dr. Juan Noe and studied in Europe with the Nobel Prize winners Otto Warburg, Jean Perrin, Louis de Broglie and Frederic G. Hopkins. In Chile, he founded a scientific academy with disciples that later obtained the National Sciences Award, such as Hector Croxatto, Jorge Mardones, Hermann Niemeyer, Luis Vargas and Jorge Allende. He carried out pioneering research in metabolism, nutrition, endocrinology, oncology and nephrogenic hypertension. He published more than 50 scientific papers in French, English and Spanish. He founded scientific societies, edited journals and created the National Commission of Nuclear Energy. His books were "The ionic acidity in the clinic", "Preventive and directed medicine", "The adrenal cortex". He was Ministry of Health between 1937 and 1938 and passed important socio-medical bills. He obtained the distinguished international awards in Europe, the U.S.A. and Latin America. The Biomedical Sciences Institute of the University of Chile carries his name

La saliva como medio de diagnóstico de VIH

La saliva como medio diagnóstico permite reconocer las concentraciones de una serie de componentes tanto endógenos como exógenos presentes en el organismo. Gracias a los anticuerpos presentes en la saliva se pueden aplicar las nuevas tecnologías biomédicas en el diagnóstico del síndrome de inmunodeficiencia humana causado por el VIH. Este novedoso método posee numerosas ventajas con respecto a las pruebas en sangre. Se plantea información sobre los fluidos bucales, los diversos componentes con posibilidad de diagnóstico presentes en la saliva y se establecen las características de un método diagnóstico (Omni-Sal® ) aplicado a personas que padecen de alguna enfermedad del complejo bucal. Descriptores.