Vinculación física entre super cáscaras de hidrógeno neutro y formación estelar reciente

Las super cáscaras de Hi (SCHi) podrían haber sido formadas por vientos estelares y/o explosiones de supernovas. Con tiempos dinámicos de vida del orden de decenas de millones de años, las estructuras de mayor tamaño sobreviven a las estrellas de gran masa que pudieran haberle dado origen. Por este motivo, las SCHi podrían ser usadas como registros fósiles para estudiar los efectos de formación estelar en la Vía Láctea. Por otra parte, durante su evolución, las SCHi podrían dar origen a nuevas generaciones de estrellas. En este trabajo investigamos la posible vinculación física entre la asociación OB Centaurus OB1 y la SCHi GSH305+01-24 del catálogo de McClure-Griffiths et al. (2002). De nuestro estudio concluimos que GSH305+01-24 no representa una estructura física real. Su estructura resulta mejor representada por dos grandes cáscaras no vinculadas entre sí. En este contexto, no resulta claro el rol que pueda haber jugado Cen OB1 en la creación de una de estas cáscaras de Hi.Many of the known galactic Hi supershells may have been formed by the combined effects of stellar winds and supernovae explosions. Having most of them dynamic lifetimes of a few times 107 yr, these huge structures are likely to outlive the stars that gave rise to them. Hence, these galactic Hi supershells may be used as fossil records of the Milky Way star formation history. Furthermore, along their evolution galactic Hi supershells may trigger star formation. In this paper we analyze the genetic link put forward by McClure-Griffiths et al. (2002) between the OB association Cen OB1 and the galactic Hi supershells GSH305+01-24. From own study we conclude that GSH305+01-24 may not represent a real physical structure. Instead, we believe that their structure is best represented by two unrelated huge Hi shells. The role played by Cen OB1 in powering one of these Hi shells is unclear for the time beeing.Fil: Corti, Mariela Alejandra. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomia; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Arnal, Edmundo Marcelo. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomia; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentin

The new HI supershell GS263-02+45 and the OB Association Bochum 7: close relatives?

Neutral hydrogen (HI) supershells are usually identified, in a given velocity range, as a brightness temperature minimum in the HI distribution that is surrounded by walls of HI emission. McClure-Griffiths et al. (2002) reported the discovery of GSH263+00+47, centered at (l,b) = (263°.0, 0°.0). The OB association Bochum 7 (l,b) = (265°.0, -2°.0) is seen in projection onto the outer border of GSH263+00+47.Instituto de Astrofísica de La PlataInstituto Argentino de Radioastronomí

The new HI supershell GS263-02+45 and the OB Association Bochum 7: close relatives?

Neutral hydrogen (HI) supershells are usually identified, in a given velocity range, as a brightness temperature minimum in the HI distribution that is surrounded by walls of HI emission. McClure-Griffiths et al. (2002) reported the discovery of GSH263+00+47, centered at (l,b) = (263°.0, 0°.0). The OB association Bochum 7 (l,b) = (265°.0, -2°.0) is seen in projection onto the outer border of GSH263+00+47.Instituto de Astrofísica de La PlataInstituto Argentino de Radioastronomí

GS263-02+45: A new HI supershell with evidence of having triggered star formation?

Aims.We look for galactic neutral hydrogen (Hi) supershells likely to be associated with massive star groupings.Methods.A neutral hydrogen (Hi) line survey carried out at the Instituto Argentino de Radioastronomía (IAR) and the Southern Galactic Plane Survey (SGPS) were the main databases used in this investigation.Results.A new Hi supershell (GS263-02+45) was found in the outer part of the Galaxy. This structure is located at a distance of 5.3 1 kpc from the Sun and has a linear diameter of about 665 40 pc. The expansion velocity of the supershell is ~14 km s. The total amount of atomic gas related to GS263-02+45 is ~2 10 . Based on the analysis of the SGPS Hi data it is concluded that the OB-association Bochum 7 is likely to be interacting with GS263-02+45. This fact together with distance and age arguments may indicate that Bochum 7 was born as a consequence of the evolution of GS263-02+45.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

GS305+04-26: Revisiting the interstellar medium around the Centaurus OB1 stellar association

Context. Massive stars deeply modify their surrounding interstellar medium (ISM) via their high throughput of ionizing photons and their strong stellar winds. In this way, they may create large expanding structures of neutral gas. Aims. We study a new large neutral hydrogen (Hi) shell, labelled GS305+04-26, and its relationship with the OB association Cen OB1. Methods. To carry out this study, we have used a multi-wavelength approach. We analyse both Hi line data retrieved from the Leiden-Argentina-Bonn (LAB) survey and new spectroscopic optical observations obtained at CASLEO, as well as make use of proper motion databases available from CDS. Results. The analysis of the Hi data reveals a large expanding structure GS305+04-26 centred at (l,b) = (305°, + 4°) in the velocity range from-33 to-17 km s -1. Based on its central velocity of-26 km s -1 and using standard galactic rotation models, a distance of 2.5 ± 0.9 kpc is inferred. This structure, elliptical in shape, has a major and minor axis of 440 and 270 pc, respectively. Its expansion velocity, total gaseous mass, and kinetic energy are ~8 km s -1, (2.4 ± 0.5) × 10 5 M âŠ(tm), and (1.6 ± 0.4) × 10 50 erg, respectively. Several stars of the OB-association Cen OB1 are seen projected onto, and within, the boundaries of GS305+04-26. Based on an analysis of proper motions, new members of Cen OB1 are identified. The mechanical energy injected by these stars could have been the origin of this Hi structure.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

Carcinoma de células escamosas do canal anal: a nova neoplasia associada com AIDS?

O carcinoma de células escamosas do canal anal é uma malignidade rara que representa 1,5% a 2% de todos os cânceres do trato gastrointestinal inferior. Entretanto, é observada uma incidência aumentada do carcinoma anal invasivo, na população soropositiva para o HIV desde a difusão da terapia antirretroviral altamente ativa. O vírus do papiloma está fortemente associado com a patogênese do câncer anal. Sexo anal e um alto número de parceiros sexuais parecem ser os fatores de risco para desenvolver câncer anal em ambos os sexos. Dor anal, sangramento e lesão palpável no canal anal são as manifestações clínicas mais comuns. O ultrassom endoanal é o melhor método diagnóstico para avaliar o tamanho do tumor, sua extensão e a infiltração para o complexo do músculo esfincteriano. A quimioradioterapia mais terapia antirretroviral é o tratamento recomendado para todos os estádios do carcinoma localizado de células escamosas do canal anal nos pacientes HIV soropositivos, devido a sua alta taxa de cura. Apresentamos um paciente que desenvolveu carcinoma do canal anal depois de um longo tempo de infecção por HIV sob tratamento com a terapia antirretroviral altamente ativa, com boa resposta virológica e imunológica.Squamous anal cell carcinoma is a rare malignancy that represents the 1.5% to 2% of all the lower digestive tract cancers. However, an increased incidence of invasive anal carcinoma is observed in HIV-seropositive population since the widespread of highly active antiretroviral therapy. Human papillomavirus is strongly associated with the pathogenesis of anal cancer. Anal intercourse and a high number of sexual partners appear to be risk factors to develop anal cancer in both sexes. Anal pain, bleeding and a palpable lesion in the anal canal are the most common clinical features. Endo-anal ultrasound is the best diagnosis method to evaluate the tumor size, the tumor extension and the infiltration of the sphincter muscle complex. Chemoradiotherapy plus antiretroviral therapy are the recommended treatments for all stages of localized squamous cell carcinoma of the anal canal in HIV-seropositive patients because of its high rate of cure. Here we present an HIV patient who developed a carcinoma of the anal canal after a long time of HIV infection under highly active antiretroviral therapy with a good virological and immunological response

Disseminated paracoccidioidomycosis with peripleuritis in an AIDS patient

La paracoccidioidomicosis es una de las micosis sistémicas endémicas más frecuentes de Latinoamérica, causada por un hongo dimorfo. En los pacientes con SIDA se presenta como una enfermedad grave y diseminada, con un amplio espectro de manifestaciones clínicas. Los niveles de linfocitos T CD4 + son habitualmente < de 200 cél/myL. Presentamos un caso de paracoccidioidomicosis diseminada con peripleuritis y abscesos subcutáneos sobre la pared torácica como manifestación inicial del SIDA. En países endémicos, la paracoccidioidomicosis debe incluirse como una complicación oportunista de los pacientes con SIDA.Paracoccidioidomycosis is one of the most frequent systemic and endemic mycoses of Latin America caused by a dimorphic fungus. In AIDS patients, paracoccidioidomycosis appears as a severe and disseminated disease with a wide spectrum of clinical findings. The CD4 counts are usually less than 200 cell/mu L. We present a case of disseminated paracoccidioidomycosis with peripleuritis and subcutaneous abscesses on the chest wall as initial manifestation of AIDS. In endemic countries, paracoccidioidomycosis should be included as an opportunistic infection in AIDS

Linfoma primario de pulmón en un paciente con sida

Extranodal involvement is common in lymphomas associated with human immunodeficiency virus infection (HIV) and acquired immunodeficiency syndrome (AIDS). However, primary pulmonary AIDS-related non-Hodgkin's lymphoma is very rare and only few reports were published in the medical literature. Clinical presentation is nonspecific, with "B" and respiratory symptoms. Also, patients were with advanced immunodeficiency at the time of diagnosis. Generally, chest radiography showed peripheral nodules or cavitary masses. Primary pulmonary lymphoma associated with AIDS is generally a high-grade B-cell non-Hodgkin lymphoma and Epstein-Barr virus is strongly associated with the pathogenesis of these tumors. We report a patient with AIDS and primary pulmonary lymphoma which clinical presentation was a total atelectasis of the left lung.El compromiso extranodal es frecuente en los linfomas asociados con la enfermedad debida al virus de la inmunodeficiencia humana y su consecuencia, el síndrome de inmunodeficiencia adquirida. Sin embargo, el linfoma pulmonar primario es muy raro y solo existen pocos casos publicados en la literatura. La presentación clínica de esta complicación es inespecífica, con síntomas "B" y manifestaciones respiratorias. Generalmente, la radiografía de tórax muestra nódulos periféricos o masas que pueden cavitarse y los pacientes presentan inmunodeficiencia severa al momento del diagnóstico. El linfoma pulmonar primario asociado con el sida es un tumor de alto grado, de células B y asociado en su patogenia con el virus de Epstein-Barr. Se relata un caso de linfoma primario de pulmón que se presentó bajo la forma radiológica de una atelectasia global del pulmón izquierdo

Linfadenitis y absceso subcutáneo por Complejo Mycobacterium avium como manifestación de síndrome inflamatorio de reconstitución inmune luego de un segundo esquema de terapia antirretroviral de gran actividad

El síndrome inflamatorio de reconstitución inmune (SIRI) es una reacción atípica e inesperada relacionada con el tratamiento antirretroviral de gran actividad (TARGA) en pacientes infectados por el virus de la inmunodeficiencia humana (VIH). El SIRI representa una respuesta inflamatoria frente a un patógeno oportunista (generalmente Mycobacterium tuberculosis, Complejo Mycobacterium avium, citomegalovirus y herpes varicela-zóster) en pacientes que responden a la TARGA con una marcada reducción de la carga viral en plasma y evidencia de una recuperación inmunológica expresada por el incremento de los niveles de linfocitos T CD4+. Presentamos el caso de un paciente con síndrome de inmunodeficiencia adquirida que desarrolló un absceso subcutáneo en muslo derecho y una adenitis supraclavicular izquierda como manifestación de SIRI por Complejo Mycobacterium avium luego del inicio de un segundo esquema de TARGA.Immune reconstitution inflammatory syndrome (IRIS) is an atypical and unexpected reaction related to highly active antiretroviral therapy (HAART) in human immunodeficiency virus (HIV) infected patients. IRIS includes an atypical response to an opportunistic pathogen (generally Mycobacterium tuberculosis, Mycobacterium avium complex, cytomegalovirus and herpes varicella-zoster), in patients responding to HAART with a reduction of plasma viral load and evidence of immune restoration based on increase of CD4+ T-cell count. We reported a case of a patient with AIDS which, after a first failure of HAART, developed a subcutaneous abscess and supraclavicular lymphadenitis as an expression of IRIS due to Mycobacterium avium complex after starting a second scheme of HAART