Understanding the effects of different HIV transmission models in individual-based microsimulation of HIV epidemic dynamics in people who inject drugs.

We investigated how different models of HIV transmission, and assumptions regarding the distribution of unprotected sex and syringe-sharing events ('risk acts'), affect quantitative understanding of HIV transmission process in people who inject drugs (PWID). The individual-based model simulated HIV transmission in a dynamic sexual and injecting network representing New York City. We constructed four HIV transmission models: model 1, constant probabilities; model 2, random number of sexual and parenteral acts; model 3, viral load individual assigned; and model 4, two groups of partnerships (low and high risk). Overall, models with less heterogeneity were more sensitive to changes in numbers risk acts, producing HIV incidence up to four times higher than that empirically observed. Although all models overestimated HIV incidence, micro-simulations with greater heterogeneity in the HIV transmission modelling process produced more robust results and better reproduced empirical epidemic dynamics.

[Diffuse tracheo-bronchial amyloidosis]. / Amiloidose traqueo-brônquica difusa.

The case of a 52 year old man, whose initial clinical manifestations were dyspnea, bloodstained sputum and malaise is reported. After the initial cancer hypothesis, a diagnosis of diffuse primary tracheo-bronchial amyloidosis was made. The amyloid substance present was not of A A type and the plasma cells next to the deposits were polyclonal. The piece-meal removal of the masses by bronchoscopy led to profuse bleeding. The patient died with sepsis. The clinical, pathological and therapeutical aspects of lower respiratory tract amyloidosis are reviewed.