La trombospondina de la saliva (TSP1) retarda la transmisión del VIH/SIDA

La trombospondina (TSPI) es una glicoproteína trimérica de P.M. 420 KD y 420,000-D (unidades de D-glucosa), proveniente de una familia de proteínas solubles, caracterizadas por poseer lugares de unión que son en número de cinco; estas son: a)Dominio heparin - sulfato proteoglicanos HSPCs; b)Dominio alfa V beta 3 integrin - arginina (Ar.) - glicina (Gly) - aspártico (Asp.) - alanina (Ala.) y con Ca 2+; c)Subdominio Valina (Val.) - treonina (Thr.) - cisteína (Cys.) - glicina (Gly.) - CD36 (receptor) o gp IV con su carboxil terminal; d)Collagen triple hélice unido al procolágeno de la trombospondina (TSPI), como se muestra en el siguiente esquema: ESQUEMA Nro. 1 Otra de las características de esta familia glicoprotéica, es considerada también como proteina moduladora en la regulación de la emigración y proliferación celular, manifestada durante la evolución de la angiogénesis, en heridas cicatrizadas y en la tumorgénesis. Así mismo, participa en la generación y en el empalme (unir, ligar) de la duplicación de genes y en número insospechado de homologías de TSP y la unión con otras matrices y proteínas solubles, por consiguiente por lo expuesto, su mecanismo bioquímico, genético, fisiológico todavía aún es desconocido.La trombospondina (TSPI) es una glicoproteína trimérica de P.M. 420 KD y 420,000-D (unidades de D-glucosa), proveniente de una familia de proteínas solubles, caracterizadas por poseer lugares de unión que son en número de cinco; estas son: a)Dominio heparin - sulfato proteoglicanos HSPCs; b)Dominio alfa V beta 3 integrin - arginina (Ar.) - glicina (Gly) - aspártico (Asp.) - alanina (Ala.) y con Ca 2+; c)Subdominio Valina (Val.) - treonina (Thr.) - cisteína (Cys.) - glicina (Gly.) - CD36 (receptor) o gp IV con su carboxil terminal; d)Collagen triple hélice unido al procolágeno de la trombospondina (TSPI), como se muestra en el siguiente esquema: ESQUEMA Nro. 1 Otra de las características de esta familia glicoprotéica, es considerada también como proteina moduladora en la regulación de la emigración y proliferación celular, manifestada durante la evolución de la angiogénesis, en heridas cicatrizadas y en la tumorgénesis. Así mismo, participa en la generación y en el empalme (unir, ligar) de la duplicación de genes y en número insospechado de homologías de TSP y la unión con otras matrices y proteínas solubles, por consiguiente por lo expuesto, su mecanismo bioquímico, genético, fisiológico todavía aún es desconocido

The infectiousness of tuberculosis patients coinfected with HIV

The current understanding of airborne tuberculosis (TB) transmission is based on classic 1950s studies in which guinea pigs were exposed to air from a tuberculosis ward. Recently we recreated this model in Lima, Peru, and in this paper we report the use of molecular fingerprinting to investigate patient infectiousness in the current era of HIV infection and multidrug-resistant (MDR) TB

Upper-Room Ultraviolet Light and Negative Air Ionization to Prevent Tuberculosis Transmission

Background Institutional tuberculosis (TB) transmission is an important public health problem highlighted by the HIV/AIDS pandemic and the emergence of multidrug- and extensively drug-resistant TB. Effective TB infection control measures are urgently needed. We evaluated the efficacy of upper-room ultraviolet (UV) lights and negative air ionization for preventing airborne TB transmission using a guinea pig air-sampling model to measure the TB infectiousness of ward air. Methods and Findings For 535 consecutive days, exhaust air from an HIV-TB ward in Lima, Perú, was passed through three guinea pig air-sampling enclosures each housing approximately 150 guinea pigs, using a 2-d cycle. On UV-off days, ward air passed in parallel through a control animal enclosure and a similar enclosure containing negative ionizers. On UV-on days, UV lights and mixing fans were turned on in the ward, and a third animal enclosure alone received ward air. TB infection in guinea pigs was defined by monthly tuberculin skin tests. All guinea pigs underwent autopsy to test for TB disease, defined by characteristic autopsy changes or by the culture of Mycobacterium tuberculosis from organs. 35% (106/304) of guinea pigs in the control group developed TB infection, and this was reduced to 14% (43/303) by ionizers, and to 9.5% (29/307) by UV lights (both p < 0.0001 compared with the control group). TB disease was confirmed in 8.6% (26/304) of control group animals, and this was reduced to 4.3% (13/303) by ionizers, and to 3.6% (11/307) by UV lights (both p < 0.03 compared with the control group). Time-to-event analysis demonstrated that TB infection was prevented by ionizers (log-rank 27; p < 0.0001) and by UV lights (log-rank 46; p < 0.0001). Time-to-event analysis also demonstrated that TB disease was prevented by ionizers (log-rank 3.7; p = 0.055) and by UV lights (log-rank 5.4; p = 0.02). An alternative analysis using an airborne infection model demonstrated that ionizers prevented 60% of TB infection and 51% of TB disease, and that UV lights prevented 70% of TB infection and 54% of TB disease. In all analysis strategies, UV lights tended to be more protective than ionizers. Conclusions Upper-room UV lights and negative air ionization each prevented most airborne TB transmission detectable by guinea pig air sampling. Provided there is adequate mixing of room air, upper-room UV light is an effective, low-cost intervention for use in TB infection control in high-risk clinical settings

Microscopic observation drug susceptibility assay for tuberculosis screening before isoniazid preventive therapy in HIV-infected persons.

BACKGROUND: Active tuberculosis (TB) must be excluded before initiating isoniazid preventive therapy (IPT) in persons infected with human immunodeficiency virus (HIV), but currently used screening strategies have poor sensitivity and specificity and high patient attrition rates. Liquid TB culture is now recommended for the detection of Mycobacterium tuberculosis in individuals suspected of having TB. This study compared the efficacy, effectiveness, and speed of the microscopic observation drug susceptibility (MODS) assay with currently used strategies for TB screening before IPT in HIV-infected persons. METHODS: A total of 471 HIV-infected IPT candidates at 3 hospitals in Lima, Peru, were enrolled in a prospective comparison of TB screening strategies, including laboratory, clinical, and radiographic assessments. RESULTS: Of 435 patients who provided 2 sputum samples, M. tuberculosis was detected in 27 (6.2%) by MODS culture, 22 (5.1%) by Lowenstein-Jensen culture, and 7 (1.6%) by smear. Of patients with any positive microbiological test result, a MODS culture was positive in 96% by 14 days and 100% by 21 days. The MODS culture simultaneously detected multidrug-resistant TB in 2 patients. Screening strategies involving combinations of clinical assessment, chest radiograph, and sputum smear were less effective than 2 liquid TB cultures in accurately diagnosing and excluding TB (P<.01). Screening strategies that included nonculture tests had poor sensitivity and specificity. CONCLUSIONS: MODS culture identified and reliably excluded cases of pulmonary TB more accurately than other screening strategies, while providing results significantly faster than Lowenstein-Jensen culture. Streamlining of the ruling out of TB through the use of liquid culture-based strategies could help facilitate the massive up-scaling of IPT required to reduce HIV and TB morbidity and mortality

Measurement of Ventilation

<p>Illustrative carbon dioxide (CO₂) concentration-decay experiment demonstrating a rapid rise in CO₂ concentration during initial release to a peak of 6,000 parts/million (ppm) followed by slow decay calculated as 0.5 ACH until the windows and doors were opened. After windows and doors were opened, CO₂ concentrations fell rapidly, indicating a calculated ventilation rate of 12 ACH. Repeated experiments of this type defined the effect of architectural and environmental variables on natural ventilation.</p

Estimated TB Transmission Risk over Time for Three Sources of Increasing Infectiousness in Naturally versus Mechanically Ventilated Facilities

<p>The estimated risk of TB infection over time for exposure to three TB source cases of different infectiousness is shown for pre-1950 naturally ventilated facilities (dotted lines) versus modern 1970–1990 naturally ventilated facilities (dashed lines) versus mechanically ventilated negative-pressure isolation facilities at 12 ACH (continuous lines). The three infectious sources are: <i>q</i> = 1.3 standard ward TB patients who infected guinea pigs studied by Riley [<a href="http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.0040068#pmed-0040068-b032" target="_blank">32</a>] (lowest three lines); <i>q</i> = 13 an untreated TB case who infected 27 coworkers in an office over 4 wk [<a href="http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.0040068#pmed-0040068-b017" target="_blank">17</a>] (middle three lines); and <i>q</i> = 249 for an outbreak associated with bronchoscopy of a TB patient [<a href="http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.0040068#pmed-0040068-b014" target="_blank">14</a>] (uppermost three lines). Median values for all measures of absolute ventilation for each category of naturally ventilated room with all windows and doors open have been used in the model.</p

Effect of Window Opening and Wind Speed on Absolute Ventilation

<p>The effect of partial and complete window opening and wind speed on natural ventilation is shown, compared with mechanically ventilated negative-pressure respiratory isolation rooms. The triplet of bars on the left of the graph represents absolute ventilation measured in naturally ventilated clinical rooms on days when wind speed was within the lowest quartile (i.e., ≤2 km/h), with windows and doors closed (<i>n</i> = 102), partially open (<i>n</i> = 167), or fully open (<i>n</i> = 86). The triplet of bars in the centre of the graph represents absolute ventilation at wind speeds in the upper three quartiles combined (i.e., >2 km/h) with windows and doors closed (<i>n</i> = 266), partially open (<i>n</i> = 74) or fully open (<i>n</i> = 240). “Partially open” was defined as at least one window and/or door open, but not all. The single bar on the right of the graph represents absolute ventilation in mechanically ventilated negative-pressure respiratory isolation wards at 12 ACH. The corresponding median ACH for the seven bars from left to right are: 1.0; 7.6; 20; 1.8; 17; 34; and 12.</p