The Chilean socio-ethno-genomic cline.

Studies of the current Chilean population performed using classical genetic markers have established that the Chilean population originated primarily from the admixture of European people, particularly Spaniards, and Amerindians. A socioeconomic-ethno-genetic cline was established soon after the conquest. Spaniards born in Spain or Chile occupied the highest Socioeconomic Strata, while Amerindians belonged to the lowest. The intermediate strata consisted of people with different degrees of ethnic admixture; the larger the European admixture, the higher the Socioeconomic Level. The present study of molecular genomic markers sought to calculate the percentage of Amerindian admixture and revealed a finer distribution of this cline, as well as differences between two Amerindian groups: Aymara and Mapuche. The use of two socioeconomic classifications - Class and Socioeconomic Level - reveals important differences. Furthermore, Self-reported Ethnicity (self-assignment to an ethnic group) and Self-reported Ancestry (self-recognition of Amerindian ancestors) show variations and differing relationships between socioeconomic classifications and genomic Amerindian Admixture. These data constitute a valuable input for the formulation of public healthcare policy and show that the notions of Ethnicity, Socioeconomic Strata and Class should always be a consideration in policy development.

Dolor torácico y hemotórax como presentación atípica de secuestro pulmonar en adulto / Chest pain and hemothorax: an atypical presentation of a pulmonary sequestration

Resumen El secuestro pulmonar es una malformación pulmonar rara, presentándose generalmente en edades tempranas. Se presenta mayoritariamente con neumonías e infecciones repetidas, distrés respiratorio y falla cardíaca; raramente en pacientes de mayor edad se presenta con hemoptisis y dolor torácico. En este artículo se describe el caso clínico de un paciente de 60 años de edad que se presenta con un infarto de un secuestro pulmonar y hemotórax.

Bronchopulmonary sequestration is a rare pulmonary malformation, usually occurring at an early age. It presents mainly with pneumonia and repetitive infections, respiratory distress and heart failure; rarely in aged patients presents with hemoptysis and chest pain. This article describes the clinical case of a 60-year-old male patient who presented an ischemic pulmonary sequestration and hemothorax.

Alterations in chromosomal synapses and DNA repair in apoptotic spermatocytes of Mus m. domesticus.

We investigated whether apoptotic spermatocytes from the mouse Mus m. domesticus presented alterations in chromosomal synapses and DNA repair. To enrich for apoptotic spermatocytes, the scrotum's temperature was raised by partially exposing animals for 15 min to a 42ºC water bath. Spermatocytes in initial apoptosis were identified in situ by detecting activated Caspase-9.  SYCP1 and SYCP3 were markers for evaluating synapses or the structure of synaptonemal complexes and Rad51 and γH2AX for detecting DNA repair and chromatin remodeling. Apoptotic spermatocytes were concentrated in spermatogenic cycle stages III-IV (50.3%), XI-XII (44.1%) and IX-X (4.2%). Among apoptotic spermatocytes, 48% were in middle pachytene, 44% in metaphase and 6% in diplotene. Moreover, apoptotic spermatocytes showed several structural anomalies in autosomal bivalents, including splitting of chromosomal axes and partial asynapses between homologous chromosomes. gH2AX and Rad51 were atypically distributed during pachytene and as late as diplotene and associated with asynaptic chromatin, single chromosome axes or discontinuous chromosome axes. Among apoptotic spermatocytes at pachytene, 70% showed changes in the structure of synapses, 67% showed changes in gH2AX and Rad51 distribution and 50% shared alterations in both synapses and DNA repair. Our results showed that apoptotic spermatocytes from Mus m. domesticus contain a high frequency of alterations in chromosomal synapses and in the recruitment and distribution of DNA repair proteins. Together, these observations suggest that these alterations may have been detected by meiotic checkpoints triggering apoptosis.

Absceso mediastínico con extensión espontánea a través de la pared torácica / Mediastinal abscess with spontaneous across chest wall extension

Introduction: Mediastinal abscess (MA) is a rare disease in the adult population. Generally presents as a systemic inflammatory response syndrome (SIRS) with high morbidity and mortality. The prognosis improves with an early diagnosis associated with an aggressive surgical drainage. Clinical case: We report a clinical case with a MA with an unusual spontaneous extension across the chest wall.

Introducción: Los abscesos mediastínicos (AM) son una patología poco frecuente en la población adulta. Su presentación clínica más habitual es la de un síndrome de respuesta inflamatoria sistémica (SIRS) con una elevada morbimortalidad. Su pronóstico mejora con un diagnóstico temprano asociado a un drenaje quirúrgico agresivo y precoz. Caso clínico: Presentamos un caso clínico de un AM con una inusual extensión espontánea a través de la pared torácica.

Análisis comprensivo de los traumatismos torácios penetrantes atendidos en Hospital Padre Hurtado de Santiago / Penetrating chest trauma

Objectives: Penetrating chest trauma (PCT) is a life threatening condition that challenges emergency surgeons daily. The aim of this study is to make an epidemiological characterization of these patients, and secondarily analyze their treatment and outcome. Methods: A retrospective analysis of a series of consecutive patients experiencing PCT who presented at our hospital, was performed from 1st May 2009 to 30th April 2013. Results: Of 274 consecutive patients who presented to the emergency department (ED) with PCT, 257 (94 percent) were male and 17 (6 percent) were female. The median age was 26 (range 15-66) years. Stab wounds (SW) accounted for 185 (68 percent) of the injuries, and 80 (29 percent) suffered from gunshot wounds (GSW). As first treatment, chest tube drainage was performed in 229 (84 percent) patients, emergent thoracotomy in 21 (8 percent) and observation, in 13 (5 percent). 26 (9 percent) patients died: 21 (81 percent) from GSW and 4 (15 percent) with SW P<0.0001; 20 (77 percent) had heart or thoracic great vessels involvement. Thoracic complications occurred in 30 (12 percent) patients. There was no mortality associated with thoracic complications. The median hospital stay was 4 days. Conclusions: PCT is frequent in our hospital compared with historical series. The majority of the patients who died had cardiac or thoracic great vessels involvement due to GSW. Therefore, healthcare improvements are needed to reduce mortality in this group of patients.

Objetivos: Los traumatismos torácicos penetrantes (TTP) son graves y desafían diariamente a los cirujanos de urgencia. El objetivo de este estudio es realizar una caracterización epidemiológica de los pacientes con TTP, y como objetivo secundario analizar el tratamiento efectuado y su evolución. Métodos: Se realizó un estudio retrospectivo de los pacientes atendidos en el Hospital Padre Hurtado de Santiago que presentaron un TTP desde el 1 de mayo de 2009 hasta el 30 de abril de 2013. Resultados: 274 pacientes que se consultaron al servicio de urgencia con un TTP, 257 (94 por ciento) eran hombres y 17 (6 por ciento) eran mujeres. La mediana de edad fue 26 (15-66) años. Lesiones por arma blanca 185 (68 por ciento), y 80 (29 por ciento) fueron por arma de fuego. Como primer tratamiento la pleurostomía fue realizada en 229 (84 por ciento) pacientes. La toracotomía de emergencia fue realizada en 21 (8 por ciento) pacientes. No se realizó tratamiento y solo observación en 13 (5 por ciento) de los casos. 26 (9 por ciento) de los pacientes murieron, 21 (81 por ciento) fueron consecuencia de lesiones por arma de fuego y 4 (15 por ciento) por arma blanca P<0,0001, 20 (77 por ciento) tenían lesiones cardíacas o de grandes vasos torácicos. 30 (12 por ciento) pacientes presentaron complicaciones torácicas. No hubo mortalidad asociada a complicaciones torácicas. La mediana de días de hospitalización fue 4. Conclusiones: El TTP es frecuente en nuestro hospital comparado con series históricas. La mayoría de los pacientes fallecidos presentaban TTP por arma de fuego con lesiones cardíacas o de grandes vasos torácicos. Se precisan mejoras asistenciales en este grupo para disminuir su mortalidad.

Resección traqueal y anastomosis primaria en traumatismo traqueo esofágico por arma de fuego / Tracheal resection and primary anastomosis in tracheoesophagueal gunshot trauma

Introduction: even though tracheoesophagueal lesions due to cervicothoracic gunshot wound are infrecuent, they should always be considered in a lesion of this kind, based on the proximity of the structures in this area, as well as the rapid compromise and deterioration that can develop these patients if the air way or vascular structures are damaged. Clinical case: we present a patient with a tracheoesophageal gunshot trauma and the surgical repair.

Introducción: las lesiones traqueo esofágicas secundarias a heridas de bala en cuello, a pesar de ser infrecuentes, siempre deben descartarse frente a un mecanismo de este tipo, no sólo por la proximidad de las estructuras sino también por el importante compromiso y rápido deterioro que pudieran presentar estos pacientes si la vía aérea o estructuras vasculares se vieran comprometidas. Caso clínico: se presenta en este trabajo un paciente con lesión traqueo esofágica secundaria a herida de bala, además de la técnica de reparación utilizada.

Hernia diafragmática complicada con rotura de víscera hueca dentro de la cavidad torácica / Complicated diaphragmatic hernia with hollow viscus rupture in thoracic cavity

Introduction: diaphragmatic hernias (DH) are a rare condition in adult patients. Most of the cases are asymptomatic findings in imaging studies. Rarely do they present as complicated cases. Clinical cases: we report two clinical cases of complicated DH, one of Bochdalek and another with history of a penetrating thoracic trauma two years before, both with hollow viscus rupture in the thoracic cavity.

Introducción: las hernias diafragmáticas (HD) son una patología relativamente poco frecuente en adultos. La gran mayoría son hallazgos asintomáticos en exámenes de imágenes, y en ocasiones debutan con complicaciones de éstas. Casos clínicos: se presentan dos casos clínicos de HD, una de Bochdalek y otra con antecedente de trauma penetrante torácico hace 2 años, ambas complicadas con rotura de víscera hueca en la cavidad torácica.

Calidad de vida en pacientes con hiperhidrosis primaria sometidos a simpatectomía videotoracoscópica / Quality of life after videothoracic simpathectomy in patients with primary hyperhidrosis

Introduction: Primary hyperhidrosis is characterized by excessive sweating that exceeds the physiological needs to maintain thermal homeostasis of the body. This study aims to assess the change in quality of life of patients operated on videothoracoscopic sympathectomy. Materials and Methods: We included all patients operated with this technique in the period between 2004 and 2010, in FACh Hospital. A standardized cuestionary was used to measure severity of hyperhidrosis and quality of life during pre and postoperative. Results: 61 patients, 57 percent female and mean age of 25 years. Preoperative sweating was barely tolerable or unacceptable in 81 percent, and preoperative quality of life was poor or very poor in 82 percent of patients. After surgery sweating was never noticed or tolerable at 85 percent and the quality of life was better in 84 percent of patients. 78 percent of patients developed compensatory sweating; however the 87 percent were satisfied with the outcome of surgery. Conclusion: Videothoracoscopic sympathectomy offers excellent results that are measurable in terms of improvement of quality of life, but often associated with the phenomenon of compensatory sweating. Despite the development of this sequel, the majorities of operated patients are satisfied with the surgical results and improve their quality of life.

Introducción: La hiperhidrosis primaria se caracteriza por sudoración excesiva que supera las necesidades fisiológicas para mantener la homeostasis térmica del cuerpo. El objetivo de este trabajo es evaluar el cambio en la calidad de vida de los pacientes operados de simpatectomía videotoracoscópica. Material y Método: Estudio de tipo transversal del total de pacientes operados con esta técnica en el Hospital Fuerza Aérea de Chile (FACh) en el período entre 2004 y 2010. Se utilizó una encuesta estandarizada y validada en la literatura para medir severidad de la hiperhidrosis y calidad de vida en período pre y postoperatorio. Resultados: 61 pacientes, 57 por ciento de género femenino y promedio de edad 25 años. La sudoración preoperatoria era apenas tolerable o intolerable en 81 por ciento y la calidad de vida preoperatoria era pobre o muy pobre en 82 por ciento de los pacientes. Posterior a la cirugía la sudoración nunca se notaba o era tolerable en 85 por ciento y la calidad de vida era mejor en 84 por ciento de los pacientes. El 78 por ciento de los pacientes operados desarrolló sudoración compensatoria, sin embargo, el 87 por ciento de los pacientes estaban satisfechos con el resultado de la cirugía. Conclusión: La simpatectomía videotoracoscópica ofrece excelentes resultados que son medibles en términos de mejoría de la calidad de vida, pero asociado frecuentemente al fenómeno de sudoración compensatoria. Pese al desarrollo de esta secuela, la mayoría de los pacientes operados están satisfechos con los resultados quirúrgicos y mejoran su calidad de vida.

Congelación ultra rápida de espermatozoides humanos: efecto sobre la función espermática y producción de especies reactiva de oxígeno / Ultra rapid freezing in human spermatozoa: effect on sperm function and reactive oxygen species production

El incremento del número de pacientes que desean mantener su fertilidad, ya sea por motivos oncológicos o de fertilidad, como son los pacientes con enfermedades infecciosas virales trasmitidas por vía sexual, o que se someten en forma voluntaria a la esterilización quirúrgica, requieren de métodos de congelación que preserven en forma adecuada la función de los espermatozoides. En el área de la criobiología, la utilización de técnicas de congelación ultrarrápida ha permitido preservar en forma exitosa ovocitos, embriones y tejido ovárico. Este método se ha incorporado recientemente para preservar el gameto masculino. El presente estudio evalúa el efecto de la congelación ultrarrápida (vitrificación) sobre la función espermática de 10 donantes normozoospérmicos. Los espermatozoides se seleccionaron por Swim-up y la solución espermática se dividió en dos subfracciones. Una fracción se vitrificó sumergiéndola directamente en nitrógeno líquido mientras que la segunda se utilizó como control. En ambas fracciones se determinaron viabilidad, movilidad, potencial de membrana mitocondrial (YMMit), integridad del ADN, reacción de acrosoma espontánea e inducida, y superóxido intracelular (O2.-). Se observó que la vitrificación preserva una adecuada función celular en un alto número de espermatozoides, siendo además un método simple, rápido y de menor costo, ya que no necesita equipo de congelación. No obstante, existe una significativa activación de la producción de especies reactivas de oxígeno, que conlleva a una prematura capacitación espermática, evento que es necesario de modular, especialmente si se utilizan estas células en técnicas de inseminación intrauterina. Futuros estudios con adición de antioxidantes a los medios de congelación parecen necesarios para optimizar esta técnica.

The number of patients who wish to maintain their fertility is ever increasing. This group of patients includes cancer patients, those with fertility problems or viral infectious diseases acquired through sexual contact and others submitting to voluntary surgical sterilization; all of the above requiring freezing methods to adequately preserve sperm function. In the field of cryobiology the use of ultra-rapid freezing techniques has successfully preserved oocytes, embryos and ovarian tissue. This method has recently been incorporated in preserving male gametes. This study evaluates the effect of ultra-rapid freezing (vitrification) on sperm function of 10 normozoospermic donors. The sperm were selected by swim-up technique and the solution divided into two fractions. One fraction is vitrified by dipping directly into liquid nitrogen and the second fraction is used as control. In both fractions, viability, motility, mitochondrial membrane potential (YMMit) DNA integrity, spontaneous and induced acrosome reaction and intracellular superoxide (O2.-) were determined. It was noted that vitrification preserves cell function in a great number of spermatozoon, and is also simple, rapid and cost effective as this method does not require freezing equipment. There is however, significant activation of the production of reactive oxygen species, which leads to premature sperm capacitation, an event necessary to modulate particularly when using these cells in intrauterine insemination techniques. Future studies with addition of antioxidants to freezing media are necessary to further improve this technique.

Hallazgos de imagen en tomografia computada de voluntarios fumadores de larga data / Findings on computed tomography imaging of long-standing volunteer smokers

The finding of pulmonary nodules in computed tomography is extremely common, with a reported prevalence ranging between 8 percent and 51 percent in volunteers, usually around 25 percent. Of these, about 2 percent to 13 percent are malignant nodules. Age, medical records of extra thoracic cancer existing 5 years before nodule detection, spiculated edges, big size, upper location and a recorded history of tobacco consumption are major risk factors for malignancy. Among these, smoking is one of the most common, with a known increased risk of malignancy (Odds ratio= 2.2). Working with the hypothesis that in smokers a higher prevalence of lesions is expected when compared to the normal population, we conducted a thoracic computed tomography study in 239 volunteers over 38 years (103 men and 135 women), who had been consuming more than 15 cigarettes a day over more than 10 years. Data were analyzed with statistical parametric and multivariate analyses. Some types of lesions were found in 82.5 percent of men and in 87.4 percent of women, being lung (53.7 percent) and mediastinal (13.8 percent) injuries the most frequent ones. Among these, bulls, scars, mediastinal lymphadenopathy and nodules constituted the main lesions (between 21.4 percent and 44.7 percent of the injuries). Nodules accounted for 21.4 percent of lesions in men and 25.2 percent in women, which falls within the normal range as described in volunteers. The cluster analysis, applied in conjunction with Jaccard coefficient of association, showed that nodules do not exist in isolation but in conjunction with other signs, forming a cluster that contains bulls, nodules, scars, mediastinal lymphadenopathy, aortic calcifications, and pleural thickening. Among lesions of potential oncological relevance, an overall finding of 5.83 percent in men and 4.44 percent in women is documented. Solitary nodules were found in 12 males and in 29 females, of whom 7 (58.3 percent) and 10 (34.5 percent), respectively...

El hallazgo de nodulos pulmonares en tomografía computada es extremadamente común, habiéndose reportado prevalencias entre 8 y 51 por ciento en voluntarios, habitualmente alrededor de 25 por ciento; de éstos, 2 a 13 por ciento serían malignos. La edad, antecedente de cáncer extratorácico más de 5 años antes del nodulo, bordes espiculados, gran tamaño, localizador superior y antecedente de consumo de cigarrillos son los principales factores de riesgo de malignidad. El cigarrillo es uno de los más comunes, con conocido aumento del riesgo (Odds ratio= 2.2). Trabajando con la hipótesis que en fumadores se espera mayor prevalencia de lesiones que en la población normal, estudiamos con tomografía computada de tórax 239 voluntarios mayores de 38 años (103 hombres, 135 mujeres), consumidores de más de 15 cigarrillos diarios por más de 10 años. Se analizaron los datos con estadística paramétrica habitual y multivariada. Encontramos 82,5 por ciento hombres y 87,4 por ciento mujeres con alguna lesión; las más frecuentes: pulmonares (53,7 por ciento) y mediastínicas (13,8 por ciento); las principales: bulas, cicatrices, adenopatías mediastínicas y nodulos (21,4 a 44,7 por ciento de las lesiones). Los nodulos correspondieron a 21,4 por ciento de las lesiones en hombres y 25,2 por ciento en mujeres, en rango habitual para lo descrito en voluntarios. El análisis de conglomerados con índice de asociación Jaccard mostró: los nodulos no se presentan aislados, evidenciándose un conglomerado que contiene: bulas, nodulos, cicatrices, adenopatías mediastínicas, calcificaciones aórticas y engrosamiento pleural. Entre las lesiones de posible importancia oncológica destacan: 5,83 por ciento en hombres y 4,44 por ciento en mujeres; 12 nodulos solitarios en hombres y 29 en mujeres, de los cuales 7 (6,8 por ciento) y 10 (7,4 por ciento) constituirían indicaciones de acciones diagnóstico-terapéuticas de mayor agresividad.

Neumomediastino espontáneo: a propósito de un caso / Spontaneous pneumomediastinum: report of one case

Presentamos el caso de neumomediastino espontáneo en un hombre joven sin asociación a algún desencadenante o patología, que consulta por dolor cervical irradiado a región supraclavicular derecha y con examen físico compatible con enfisema cervical. La evaluación inicial incluyó estudio radiológico de cuello, columna cervical y tórax. La tomografía axial computada demostró un neumomediastino con extensión al cuello sin patología pulmonar subyacente, se complementó el estudio con esofagograma. La evolución del paciente fue satisfactoria y asintomática, como se describe en los casos reportados en la literatura internacional. Se discute la fisiopatología del neumomediastino.

We report a 22 years old male that consulted in the emergency room for a painful cervical mass that appeared spontaneously and grew rapidly. On physical examination cervical and supraclavicular subcutaneous emphysema was noted. Neck and chest CAT scan showed a pneumomediastinum in the absence of lung lesions. The condition subsided spontaneously in 24 hours and the patient remains asymptomatic.

Alteration of nuclear architecture in male germ cells of chromosomally derived subfertile mice.

The mammalian cell nucleus consists of numerous compartments involved in the regular unfolding of processes such as DNA replication and transcription, RNA maturation, protein synthesis and cell division. Knowledge is increasing of the relationships between high-order levels of chromatin organization and its spatial organization, and of how these relationships contribute to the various functions carried out in the nucleus. We have studied the spatial arrangement of mouse telocentric chromosomes 5, 11, 13, 15, 16 and 17, some of their metacentric Robertsonian derivatives, and X and Y chromosomes by whole chromosome painting in male germ (spermatogonia, pachytene spermatocytes and spermatids) and Sertoli cells of homozygous and heterozygous individuals. Using dual-colour fluorescence in situ hybridization we found that these chromosomes occupy specific nuclear territories in each cell type analysed. When chromosomes are present as Robertsonian metacentrics in the heterozygous state, that is, as Robertsonian metacentrics and their homologous telocentrics, differences in their nuclear positions are detectable: heterozygosity regularly produces a change in the nuclear position of one of the two homologous telocentrics in all the cell types studied. In the Robertsonian heterozygotes, the vast majority of the Sertoli cells show the sex chromosomes in a condensed state, whereas they appear decondensed in the Robertsonian homozygotes. As the Robertsonian heterozygosities we studied produce a chromosomally derived impairment of male germ-cell differentiation, we discuss the possibility that changes in chromosome spatial territories may alter some nuclear machinery (e.g., synapsis, differential gene expression) important for the correct unfolding of the meiotic process and for the proper functioning of Sertoli cells.

Organisation of complex nuclear domains in somatic mouse cells.

The number and associations of heterochromatin chromocenters, nucleoli, centromeres and telomeres were studied in the nucleus of different somatic cells of Mus domesticus. Fibroblasts of the cell line 3T3, kidney cells (primary culture), and bone marrow cells were used. The above mentioned nuclear and chromosome markers were identified by DAPI/actinomycin D, indirect immunofluorescence with anti-centromere antibodies, silver impregnation for nucleolar proteins and fluorescence in situ hybridisation (FISH) with telomeric probes. The quantitative analysis of the nuclei showed that the pericentromeric heterochromatin is organised in about 18 chromocenters per nucleus in the 3T3 cells, and about seven in kidney and bone marrow cells, having generally a peripheral distribution in the nucleus of all the studied cells. Several aggregated centromeres were participating in each of the chromocenters, about four centromeres per 3T3 cell and about six centromeres per kidney and bone marrow cells. Some of the chromocenters were also in close association with nucleoli. The number of telomeric labels per nucleus was as expected for each chromosome set (2n = 68-70 and 2n = 40). About half of the telomeric signals were loosely aggregated within the heterochromatic blocks while the rest were distributed in the nucleus as unrelated units not bound with chromocenters. The three cell types have complex nuclear territories formed by different chromosomal domains: the pericentromeric heterochromatin, centromeres, proximal telomeres and nucleoli. With the exception of some bone marrow cells, we have not found a nuclear polarisation of the analysed chromosomal markers compatible with the Rabl configuration. However, Rabl anaphasic polarisation allows the contact of centromeric regions making possible that centromeric associations arise. If in addition, associative elements such as constitutive heterochromatin or nucleoli are close to the centromeric regions, like in Mus domesticus chromosomes, then the associations might be consolidated and persist until the interphase. These associations may be the origin of the nuclear domains described here for Mus domesticus somatic cells.

Non-random distribution of the pericentromeric heterochromatin in meiotic prophase nuclei of mammalian spermatocytes.

The central or peripheral distribution of condensed chromatin (CC) was studied in pachytene spermatocyte nuclei in Mus domesticus, 2n = 40; Pudu puda, 2n = 70; Ctenomys opimus, 2n = 26 and Octodon degus, 2n = 58. Species were chosen according to the morphological characteristics of their chromosomal complements and in particular, the terminal or medial chromosomal localisation of the pericentromeric constitutive heterochromatin. Counts were made by defining the areas corresponding to peripheral and central location in each nuclear section from a series. The null hypothesis (i.e. random distribution of CC) was rejected. In the nuclear sections of Mus domesticus and Pudu puda, 69% and 74% of CC, respectively, was found in the peripheral nuclear space, while in those of Octodon degus and Ctenomys opimus, 69% and 65% of CC, respectively, was found in the central nuclear space. We estimate that if the CC measured in spermatocyte nuclei corresponds mainly to pericentromeric constitutive heterochromatin, the distribution found is consistent with that expected in accordance with the nuclear architecture model for meiocytes (Fernández-Donoso, 1982; Fernández-Donoso & Berrios, 1985). This model proposes a peripheral nuclear localisation for pericentromeric heterochromatin of telocentric bivalents and a relatively central nuclear localisation for pericentromeric heterochromatin of metacentric bivalents. We also discuss some of the biological consequences that could arise from the conservation of such distributions.

Resección de nódulos pulmonares por videotoracoscopía / Pulmonary nodules resection by videothoracoscopy

El diagnóstico de nódulos pulmonares es difícil con técnicas no invasivas. El objetivo de este trabajo es analizar la experiencia en el diagnóstico y tratamiento de estas lesiones por videotoracoscopía. Se estudiaron 59 pacientes operados con esta técnica entre Enero de 1995 y Junio de 1997. En este período se intervinieron 25 nódulos benignos y 34 malignos, de los cuales 32 fueron metastásicos y 2 primarios pulmonares. El promedio de edad fue de 52 años (40 para las mujeres y 50 años los hombres). El tiempo operatorio promedio fue de 66 minutos con extremos de 20 a 150 minutos. Hubo 4 conversiones que corresponde al 6,7 por ciento de la casuístíca. El promedio de días hospitalarios postoperatorios fue de 3,74. En 4 pacientes (6,7 por ciento.) se presentaron complicaciones menores y no hubo mortalidad. La videotoracoscopía es un excelente método diagnóstico y en ocasiones terapéutico para el manejo de nódulos pulmonares, con baja morbilidad, corta estadía hospitalaria y sin mortalidad en este estudio

Neumotórax espontáneo: modalidades terapéuticas / Spontaneous pneumothorax: therapeutical ways

En este artículo se analizan los diferentes tipos de neumotórax y sus diversas modalidades terapéuticas. Se hace hincapié sobre los tratamientos complementarios para evitar las recurrencias. Se plantean las indicaciones quirúrgicas considerando las características clínicas de cada caso, siendo el objetivo fundamental la resección de bulas y la obliteración del espacio pleural por métodos químicos o mecánicos. Se destacan los beneficios que representa actualmente la videotoracoscopía en el tratamiento del neumotórax tanto primario como secundario

Antimitochondrial antibody detection by indirect immunofluorescence on mouse sperms.

Antimitochondrial antibodies (AMA) are characteristically present in the serum of patients with primary biliary cirrhosis (PBC). AMA detection constitutes an important step for the clinical diagnosis of PBC, the indirect immunofluorescence against cryostat sections of rat of mouse organs being the most common method used. This study presents an alternative method for AMA detection by indirect immunofluorescence using mouse sperms as substrate. Sera of 17 patients with PBC were examined for AMA using mouse sperms and frozen sections of rat kidney. With mouse sperms as substrate, all PBC sera were found to be AMA positive showing an intense fluorescent reaction on the mitochondrial sheath of mouse sperms (100% sensitivity). No false positive results were obtained with normal sera. Sera of 22 patients with collagen diseases (systemic lupus erithematosus and progressive systemic sclerosis) having defined reactivity to antigens other than mitochondrial antigens were also examined for AMA with both substrates; 19 of them resulted AMA negative. AMA diagnosis on mouse sperm substrate was found to be more sensitive than conventional rat kidney substrate. In addition, it has the advantage that it facilitates for the observer the visualization and reading of the fluorescent reaction on the mitochondria, due to the particular distribution of them on mouse sperms.