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This Model (this + model)
Selected AbstractsPopulation pharmacokinetics of cefepime in neonates with severe nosocomial infectionsJOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 3 2008V. Lima-Rogel MD Summary Objective:, To define the pharmacokinetic behaviour of cefepime in neonates with severe nosocomial infections using a mixed effects model. Patients and methods:, Thirty-one newborn infants were included in the study; 10 additional infants participated in the validation of the pharmacokinetic model. Cefepime CL and V were determined using an open monocompartmental model with first-order elimination. The influence of demographic and clinical characteristics on the model was evaluated. The non-linear mixed effect model (nonmem) program was used to determine the pharmacokinetic population model. Results:, The mean corrected gestational age for infants participating in the construction and validation of the model were 35 and 33 weeks, respectively. Factors included in the final pharmacokinetic model were body surface area (BSA) and calculated CLCR. The final population model was CL (L/h) = 0·457 BSA (m2) + 0·243 CLCR (L/h) and V(L) = 4·12 BSA (m2). This model explains 33·3% of the interindividual variability for CL and 12·8% for V. This model was validated in ten neonates with nosocomial infections by assessing the predictive capacity of plasma cefepime concentrations using a priori and Bayesian strategies. Conclusions:, The predictive performance of this population model for cefepime plasma concentrations was adequate for clinical purposes and can be used for individualizing cefepime therapy in newborn infants with severe infections. Cefepime plasma concentrations can be predicted based on BSA and calculated CLCR. Cefepime therapy using a 250 mg/m2 dose administered every 12 h is adequate to achieve plasma concentrations greater than 8 ,g/mL during more than 60% of the dosing interval and is expected to be effective in the treatment of bloodstream infections caused by most gram negative organisms in newborn infants. A dose of 550 mg/m2 would be required for the treatment of infections caused by Pseudomonas sp. [source] An ongoing process of inner negotiation , a Grounded Theory study of self-management among people living with chronic illnessJOURNAL OF NURSING AND HEALTHCARE OF CHRONIC ILLNE SS: AN INTERNATIONAL INTERDISCIPLINARY JOURNAL, Issue 4 2009Åsa Audulv RN Aim., The aim of this study was to better understand the main concern of self-management processes among people with chronic illness. Background., One aspect of living with chronic illness is self-management that can reduce the illness impact on daily life and promote future health. Although factors that influence self-management have been identified in previous research, little attention has been brought to the process of making self-management decisions. In clinical settings, use of a theory could facilitate patient-empowering approaches. Method., The data collection for this Grounded Theory was mostly conducted in 2006. Data were collected by interviews with 26 adults with a variety of chronic illnesses, including rheumatoid arthritis, diabetes mellitus, inflammatory bowel syndrome, multiple sclerosis, ischaemic heart disease and chronic kidney failure. Results., Individuals are conflicted by competing preferences when taking decisions about self-management. Consequently, the decision-making process can be understood as an ongoing inner negotiation between different incompatible perspectives, e.g. social needs vs. medical needs. The process of negotiating self-management starts with the individual's considering beliefs about health and illness, which make the individual face illness threats and the need for self-management. Several aspects influence negotiating self-management namely, assessing effects of self-management; evaluating own capacity; perceiving normality or stigmatisation; and experiencing support and external resources. The process has been demonstrated in a model. Conclusions., The process of negotiating self-management is an ongoing inner debate rather than a one-time decision. This opens up new ways of understanding, and communicating with, patients. The described model also links behavioural theories and research findings in a comprehensive understanding. Relevance to clinical practice., This model could be applicable as a communication tool for health-care providers in identifying barriers to, and resources in, self-management behaviour among individuals with chronic illness. [source] The practice of non-parametric estimation by solving inverse problems: the example of transformation modelsTHE ECONOMETRICS JOURNAL, Issue 3 2010Frédérique Fève Summary, This paper considers a semi-parametric version of the transformation model , (Y) =,,X+U under exogeneity or instrumental variables assumptions (E(U,X) = 0 or . This model is used as an example to illustrate the practice of the estimation by solving linear functional equations. This paper is specially focused on the data-driven selection of the regularization parameter and of the bandwidths. Simulations experiments illustrate the relevance of this approach. [source] Laboratory Forum: Experimental Models of Peyronie's Disease.THE JOURNAL OF SEXUAL MEDICINE, Issue 2 2009Implications for New Therapies ABSTRACT Introduction., Despite its high prevalence and impact on the quality of life of patients, and that it is an excellent model for the study of fibrotic processes, Peyronie's disease (PD) is an orphan disease in biomedical research. The development of animal and cell culture models has advanced substantially the understanding of its molecular and cellular pathology and the proposal of new therapies. Aim., To review the literature pertaining to the use of these models for the study of PD. Methods., PubMed search conducted from the first report of an animal model for PD. Results., This model, based on the finding that transforming growth factor ,1 (TGF,1) is overexpressed in the PD plaque, consists on the injection of TGF,1 into the tunica albuginea of the rat. This leads to a PD-like plaque retaining many of the histological and biochemical features of human PD. Another rat model, based on the hypothesis that the PD plaque arises from trauma to the penis, causing fibrinogen extravasation that initiates as fibrin a fibrotic response, consists on injection of fibrin into the tunica. The cell culture model is based on the demonstration that myofibroblasts are abundant in the human PD plaque. Conclusions., These models have: (i) clarified the role of microtrauma, myofibroblasts, and oxidative stress in plaque development; (ii) demonstrated that this tissue is under sustained turnover by fibrotic and antifibrotic mechanisms; (iii) showed the interplay of collagenolytic and fibrinolytic systems and their inhibitors; (iv) detected an endogenous antifibrotic process consisting of the expression of inducible nitric oxide synthase that counteracts oxidative stress, collagen synthesis, and myofibroblast generation; (v) characterized the antifibrotic effects of chronic treatment with phosphodiesterase type 5 (PDE5) inhibitors; (vi) discovered the cytogenetic instability of PD cells and alterations in their gene expression; and (vii) detected stem cells in the tunica albuginea with a potential role in fibrosis and ossification. Gonzalez-Cadavid NF, and Rajfer J. Experimental models of peyronie's disease. Implications for new therapies. J Sex Med 2009;6:303,313. [source] Structural study of the low-temperature phase of TlH2PO4 at 180,KACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2002E. Álvarez-Otero The low-temperature phase of TlH2PO4 has been studied by X-ray diffraction. A structural model is proposed with space group P. This model is compared with the structure of the antiferroelectric phase of TlD2PO4 at room temperature to analyze the expected isomorphism at low temperature. Given the structural distortion of TlH2PO4, such isomorphism present in the common high-temperature phase is not recovered in this phase. Through the analysis of the displacements of the PO4 groups there is some evidence that the ordering of the H atoms responsible for the appearance of antiferroelectricity seems to be incomplete. An exhaustive study of the detected ferroelastic domains is also performed. [source] | ||||||||||