[Measles: Historical background and current situation]. / Sarampión: Antecedentes históricos y situación actual.

Measles is still a major cause of child morbidity and mortality. In recent years, it has become a global public health problem, attributed to low vaccination coverage observed in different countries. In order to control it, a highly effective live virus vaccine is available, which was used for the first time in Chile in 1964, covering practically the whole country in a short period of time. This was the first world experience, which was later imitated by other countries leading to a significant drop in mor bidity and mortality rates. Its effectiveness has been amply demonstrated, but it requires coverage maintenance higher than 95%. In Chile, minor endemic situation persisted until 1993. In recent years, there have been some reduced outbreaks and sporadic cases linked to contacts with imported cases, however, according to recent data, measles is now circulating in more than 160 countries at an unprecedented spread level, where infected travelers are the main vehicle of transmission. In Chile, the Ministry of Health has decided to strengthen and update the vaccination of susceptible groups, especially travelers. This update reviews historical aspects and current information on this re-emer ging disease, showing its high epidemiological impact on the pediatric and adult population globally.

Sarampión: antecedentes históricos y situación actual / Measles: historical background and current situation

Resumen: El sarampión sigue siendo una causa importante de morbilidad y mortalidad en el niño. Durante estos últimos años, se ha convertido en un problema de salud pública mundial, que se atribuye a bajas coberturas de vacunación observadas en diferentes países. Para su control se dispone de una vacuna a virus vivo, altamente eficaz, que fue empleada por primera vez en Chile en 1964, logrando cobertura en prácticamente todo el país en un breve plazo. Esta fue la primera experiencia mundial, imitada lue go por otros países que resulto en una importante caída de las tasas de morbilidad y de mortalidad. Su eficacia ha sido ampliamente demostrada, pero requiere de la mantención de coberturas superiores a 95%. En Chile persistió una situación de endemia de menor magnitud hasta el año 1993. En años recientes, ha habido algunos brotes reducidos y casos esporádicos vinculados a contactos con casos importados, sin embargo, según datos recientes, el sarampión está circulando ahora en más de 160 países en un nivel de propagación sin precedentes, siendo los viajeros infectados el principal vehículo de transmisión. En Chile, el Ministerio de Salud ha decidido reforzar y poner al día la vacunación de grupos susceptibles, en especial viajeros. En esta actualización se revisan aspectos históricos y la información actual de esta enfermedad que ha resurgido mostrando su alto impacto epidemiológico en la población pediátrica y adulta a nivel global.

Abstract: Measles is still a major cause of child morbidity and mortality. In recent years, it has become a global public health problem, attributed to low vaccination coverage observed in different countries. In order to control it, a highly effective live virus vaccine is available, which was used for the first time in Chile in 1964, covering practically the whole country in a short period of time. This was the first world experience, which was later imitated by other countries leading to a significant drop in mor bidity and mortality rates. Its effectiveness has been amply demonstrated, but it requires coverage maintenance higher than 95%. In Chile, minor endemic situation persisted until 1993. In recent years, there have been some reduced outbreaks and sporadic cases linked to contacts with imported cases, however, according to recent data, measles is now circulating in more than 160 countries at an unprecedented spread level, where infected travelers are the main vehicle of transmission. In Chile, the Ministry of Health has decided to strengthen and update the vaccination of susceptible groups, especially travelers. This update reviews historical aspects and current information on this re-emer ging disease, showing its high epidemiological impact on the pediatric and adult population globally.

A consensus protocol for the management of medication-overuse headache: Evaluation in a multicentric, multinational study.

INTRODUCTION: The management of medication-overuse headache (MOH) is often difficult and no specific guidelines are available as regards the most practical and effective approaches. In this study we defined and tested a consensus protocol for the management of MOH on a large population of patients distributed in different countries. SUBJECTS AND METHODS: The protocol was based on evidence from the literature and on consolidated expertise of the members of the consensus group. The study was conducted according to a multicentric interventional design with the enrolment of 376 MOH subjects in four centres from Europe and two centres in Latin America. The majority of patients were treated according to an outpatient detoxification programme. The post-detoxification follow-up lasted six months. RESULTS: At the final evaluation, two-thirds of the subjects were no longer overusers and in 46.5% of subjects headache had reverted back to an episodic pattern of headache. When comparing the subjects who underwent out-patient detoxification vs those treated with in-patient detoxification, both regimens proved effective, although the drop-out rate was higher in the out-patient approach. CONCLUSIONS: The present findings support the effectiveness and usability of the proposed consensus protocol in different countries with different health care modalities.

Disability, anxiety and depression associated with medication-overuse headache can be considerably reduced by detoxification and prophylactic treatment. Results from a multicentre, multinational study (COMOESTAS project).

OBJECTIVE: The objective of this article is to investigate whether headache-related disability, depression and anxiety can be reduced by detoxification and prophylactic treatment in patients with medication-overuse headache (MOH). METHODS: Patients with MOH were included from six centres in Europe and Latin America in a seven-month cohort study. Before and six months after treatment, the degree of disability was measured by the Migraine Disability Assessment (MIDAS) questionnaire, while anxiety and depression were measured by the Hospital Anxiety and Depression Scale (HADS). RESULTS: A total of 694 patients with MOH were included, of whom 492 completed the study. Headache days were reduced by 58.4% from 23.6 to 9.8 days per month at six months ( P < 0.001). The MIDAS score was reduced by 57.1% from baseline 59.9 to 25.7 ( P < 0.001). Number of patients with depression was reduced by 50.7% from 195 to 96 and number of those with anxiety was reduced by 27.1% from 284 to 207 (both P < 0.001). CONCLUSIONS: Disability, depression and anxiety were considerably reduced in patients with MOH by detoxification and prophylactic treatment. This emphasises the urgent need for increased awareness about avoiding overuse of headache medications and demonstrates that not only headache frequency but also disability are remarkably improved by adequate intervention.

Características de la enfermedad cerebrovascular en un Servicio de Cuidados Intermedios Neurológicos, en Chile. Análisis de 459 pacientes consecutivos / Cerebrovascular disease in a Neurologic Intermediate Care Unit in Chile. Analysis of 459 consecutive patients

Background: Stroke is the second cause of mortality and the first cause of morbidity in Chile and worldwide. Nowadays there is a major interest in introducing new therapies applying evidence based medicine for these patients. Aim: To describe the clinical profile of patients attended after a stroke, to determine stroke subtypes and their risk factors. Material and methods: Retrospective review of clinical records of 459 patients (mean age 65±48 years, 238 female) that were admitted to our unit during a period of 37 months. Results: Sixty three percent of patients had an ischemic stroke, 14% had an hemorrhagic stroke, 15% had a transient ischemic attack, 2% had a cerebral venous thrombosis and 6% a subarachnoidal hemorrhage. The global mortality was 1%. Seventy percent of patients had a history of high blood pressure. Conclusions: The most common type of stroke is ischemic and high blood pressure is the main risk factor.

[Cerebrovascular disease in a Neurologic Intermediate Care Unit in Chile. Analysis of 459 consecutive patients]. / Características de la enfermedad cerebrovascular en un Servicio de Cuidados Intermedios Neurológicos, en Chile. Análisis de 459 pacientes consecutivos.

BACKGROUND: Stroke is the second cause of mortality and the first cause of morbidity in Chile and worldwide. Nowadays there is a major interest in introducing new therapies applying evidence based medicine for these patients. AIM: To describe the clinical profile of patients attended after a stroke, to determine stroke subtypes and their risk factors. MATERIAL AND METHODS: Retrospective review of clinical records of 459 patients (mean age 65+/-48 years, 238 female) that were admitted to our unit during a period of 37 months. RESULTS: Sixty three percent of patients had an ischemic stroke, 14% had an hemorrhagic stroke, 15% had a transient ischemic attack, 2% had a cerebral venous thrombosis and 6% a subarachnoidal hemorrhage. The global mortality was 1%. Seventy percent of patients had a history of high blood pressure. CONCLUSIONS: The most common type of stroke is ischemic and high blood pressure is the main risk factor.

Ventilación mecánica no invasiva en pacientescon enfermedades neuromusculares y enpacientes con alteraciones de la caja torácica / Noninvasive mechanical ventilation in patients with neuromuscular diseases and in patients with chest restriction

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Muscle cell outside and inside: the nascent approach of a clinician.

Understanding muscle cell in disease and health is an unfinished process. Following the lead of Jaime Alvarez, I have had the opportunity of working on two complementary approaches to this field. One is the study of muscle cell surface molecules. Both synaptic muscle molecules, such as the asymmetric form of acetylcholinesterase, and extrasynaptic molecules, such as the extracellular matrix proteoglycans, are regulated by the motor nerve activity. This illustrates one of Jaime's teachings: cell phenotypes are a dynamic process that reflects the influence of other cells (Alvarez, 2001). Proteoglycans have many functions, including growth factor receptors. Studying them in muscular dystrophy will contribute to the comprehension of the muscle regeneration failure, characteristic of this disease. Muscle cells are highly dependent upon energy production, and the mitochondriae produce most of it. These organelles are unique in having their own genome. Mutations in these genes have recently been recognized as the cause of human disease and originally in muscle pathology. The physiopathology of these diseases is summarized here.

Mitochondrial neurogastrointestinal encephalomyopathy: diagnosis by rectal biopsy.

A 14-year-old girl with the mitochondrial neurogastrointestinal encephalopathy syndrome had an 8-year history of intestinal pseudoobstruction with abdominal pain, persistent vomiting, gastric and duodenal dilatation, and duodenal diverticulosis. The child appeared chronically malnourished and had severe growth failure. Multisystem involvement was evident with the presence of ptosis, external ophthalmoplegia, muscle wasting, peripheral neuropathy, and diffuse white matter disease seen on magnetic resonance imaging. Lactic acidosis and increased cerebrospinal fluid protein were observed. Mitochondrial enzyme analysis of fresh-frozen skeletal muscle revealed a respiratory chain defect. Molecular genetic studies showed multiple mitochondrial DNA deletions. Pathologic findings in the intestine included atrophy of the external layer of the muscularis propria and an increased number of abnormal-appearing mitochondria in ganglion and smooth-muscle cells. Microvesicular steatosis was observed in liver, skeletal, and gastrointestinal smooth muscle, and Schwann cells of peripheral nerve. Brightly eosinophilic inclusions in the cytoplasm of gastrointestinal ganglion cells were visible by light microscopy, which were confirmed to be megamitochondria by ultrastructural studies. This is the first report of abnormal mitochondria observed in intestinal ganglion and smooth-muscle cells in this syndrome.

Sural/radial amplitude ratio in the diagnosis of mild axonal polyneuropathy.

As proximal nerves are relatively spared in length-dependent, axonal polyneuropathy, we theorized that a sural/radial amplitude ratio (SRAR) might be a sensitive indicator of mild polyneuropathy. In this study, sural amplitudes and SRARs in patients with signs of mild axonal polyneuropathy were compared to those of normal, age-matched control subjects. Sural and radial sensory responses were measured in a standard fashion in all subjects. Thirty polyneuropathy patients had an average SRAR of 0.29 as compared to 0.71 for the 30 normal subjects. An SRAR of less than 0.40 was a strong predictor of axonal polyneuropathy, with 90% sensitivity and 90% specificity, as compared to an absolute sural amplitude of less than 6.0 microV, which had sensitivity of only 66%. Additionally, unlike the sural amplitude, the ratio did not vary significantly with age. We conclude that the SRAR is a sensitive, specific, age-independent electrodiagnostic test for mild axonal polyneuropathy.

Sensory ataxic neuropathy as the presenting feature of a novel mitochondrial disease.

Four unrelated patients presented with a severe sensory ataxic neuropathy in association with dysarthria and chronic progressive external ophthalmoplegia. Electrophysiologic and pathologic studies showed severe axonal loss disproportionately affecting sensory nerves. Molecular genetic analysis revealed multiple mitochondrial DNA deletions in muscle and peripheral nerve. Sensory ataxic neuropathy may be the predominant and presenting manifestation of a mitochondrial disorder, and a mitochondrial etiology should be included in its differential diagnosis. The triad of sensory ataxic neuropathy, dysarthria, and ophthalmoparesis (SANDO) may represent a novel mitochondrial disease associated with multiple mitochondrial DNA deletions.

Muscle pathology and clinical features of the sarcolemmopathies.

We report the clinical features and the muscle pathology in 2 patients with congenital muscular dystrophy (CMD) secondary to merosin deficiency and in 2 patients with sarcoglycan (adhalin) deficiency. Electron microscopic examination revealed sarcolemmal defects in non-necrotic muscle fibers in all cases. These pathological findings are indistinguishable from those of Duchenne/Becker muscular dystrophy. We suggest that the similarities in histological findings reflect a common pathogenetic mechanism, i.e., a structural weakening of the sarcolemma with an increased susceptibility to rupture under mechanical stress. We propose the term sarcolemmopathy as an all-encompassing rubric for these disorders.

CD8 and CD4 T cell-mediated polymyositis complicating the HTLV-1 associated myelopathy. Quantitative evaluation of corticosteroid treatment.

INTRODUCTION: Inflammatory myopathy is a treatable cause of worsening in the spectrum of neurological conditions that may develop during the course of HTLV-1 infection. MATERIAL AND METHODS: To investigate the cause of subacute worsening in the strength of a 46-y-old black male with HTLV-1 associated myelopathy we performed electrodiagnostic examination and a muscle biopsy which was studied with histochemistry, immunocytochemistry and electron microscopy. Serial measurements of isometric muscle strength were performed during the course of corticosteroid treatment. RESULTS: The muscle biopsy showed evidence of denervation atrophy and prominent inflammatory changes with autoaggressive features. Lymphocyte typing showed a predominance of CD8+ T cells. The patient had sustained, marked improvement in strength, especially of the upper extremities, with oral, high single-dose, alternate-day prednisone therapy. CONCLUSION: A muscle biopsy should be considered in all patients with HTLV-1 associated weakness, especially when electromyography indicates possible coexisting primary muscle involvement and/or serum creatine kinase levels are elevated. HTLV-1-associated polymyositis can be successfully treated with corticosteroids.

Clinical spectrum of mitochondrial diseases.

Mitochondrial diseases include myopathies and multisystem disorders. They are characterized by morphologic and biochemical abnormalities of mitochondria. Their genetic characteristics-maternal inheritance, heteroplasmy, mitotic segregation, and threshold effect-are unique. The clinical phenotypes are considerably heterogeneous, but the clinical presentation in many cases is characteristic or suggestive. We review the clinical features of the most prevalent mitochondrial encephalomyopathy syndromes, their molecular genetic basis, isolated clinical symptoms, and uncommon presentations. Molecular genetic diagnosis is available for the common syndromes and has revolutionized their diagnosis. Future therapeutic advances, based on the precise genetic etiology, are anticipated. Mitochondrial dysfunction may be a more frequent pathogenetic mechanism than the prevalence of the classic mitochondrial syndromes would indicate, as there is an association between the accumulation of mitochondrial DNA mutations in postmitotic tissues and neurologic and systemic degenerative diseases.

Assembly and disassembly of axonal microtubules of the toad Xenopus laevis under the effect of temperature.

In toads Xenopus laevis living at 11 degrees (winter), the microtubular density of 4-microns myelinated axons of lumbosacral nerves was assessed with the electron microscope. In controls, the density was 11.2 microtubules/microns2. In nerves incubated at 0 degrees, microtubules decreased following a simple exponential curve with a half time of 4.7 min (k = 0.149 min-1); residual microtubules were 4.5%. After rewarming, the full complement of microtubules reappeared within 60 min. In steady state, the microtubular density exhibited a linear relationship with temperature (range: 0-22 degrees; slope 0.94 microtubules/microns 2 per degree; r, 0.96). After heating the nerve by 11 degrees above the physiological temperature, microtubules increased by 83%, whereby the pool of unpolymerized tubulin was at least 2.7 mg/ml of axoplasm. A seasonal variation of the microtubular density was observed which accorded with the environmental temperature. The macroscopic kinetics of microtubule disassembly in the axoplasm is similar to that reported for purified tubulin but that of assembly is slower. Microtubules of peripheral axons of Xenopus are cold-labile and vary during the annual cycle.