1,721,003 research outputs found

    HIV evolution: a quantification of the effects due to age and to medical progress

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    Abstract. This paper offers an analysis of HIV/AIDS dynamics, defined by CD4 levels and Viral load, carried out from a macroscopic point of view by means of a general stochastic model. The model focuses on the patient’s age as a relevant factor to forecast the transitions among the different levels of seriousness of the disease and simultaneously on the chronological time. The third model considers the two previous features simultaneously. In this way it is possible to quantify the medical scientific progresses due to the advances in the treatment of the HIV. The analyses have been performed through non-homogeneous semi-Markov processes. These models have been implemented by using real data provided by ISS (Istituto Superiore di Sanità, Rome, Italy). They refer to 2159 subjects enrolled in Italian public structures from September 1983 to January 2006. The relevant results include also the survival analysis of the infected patients. The computed conditional probabilities show the different responses of the subjects depending on their ages and the elapsing of time

    Bioimpedance analysis and resting energy expenditure in undernourished and refed anorectic patients.

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    ABSTRACT Anthropometry, bioimpedance analysis (BIA) and resting energy expenditure (REE) were evaluated in young female patients affected by anorexia nervosa who were either severely malnourished (MnA) or already refed (RfA) and in a control group of healthy young women (WnC). Fat-free mass (FFM) and fat mass (FM), evaluated from skinfold thickness, were severely decreased in the MnA group while they were very similar in the RfA group and in the WnC group. With respect to BIA parameters, impedance (Z) was significantly higher in absolute terms in the MnA but lower than in the other groups when expressed as specific impedance, i.e. after normalization for both FFM and height. Phase angle significantly differed between the three groups, being significantly (P < 0.01) lower in the MnA (3.70+/- 0.83 degrees) and the RfA (4.36 +/- 0.82) than in the WnC (5.17 +/- 0.40). REE was comparable in RfA subjects and WnC subjects, while it was sharply decreased (P < 0.01) in the MnA patients both in absolute value and after adjustment for body composition (FFM and FM) or body weight. This cross-sectional study shows that marked changes in BIA parameters occur in undernourished anorectic patients and also in the anorectic subjects who were previously very underweight but studied only after having already regained a normal body size. REE was deeply decreased in the undernourished anorectic women even when the differences in body composition or Wt were taken into account, indicating the occurrence of a significant adaptation of energy expenditure to chronic underfeeding
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