Differential dynamic properties of scleroderma fibroblasts in response to perturbation of environmental stimuli.

Diseases are believed to arise from dysregulation of biological systems (pathways) perturbed by environmental triggers. Biological systems as a whole are not just the sum of their components, rather ever-changing, complex and dynamic systems over time in response to internal and external perturbation. In the past, biologists have mainly focused on studying either functions of isolated genes or steady-states of small biological pathways. However, it is systems dynamics that play an essential role in giving rise to cellular function/dysfunction which cause diseases, such as growth, differentiation, division and apoptosis. Biological phenomena of the entire organism are not only determined by steady-state characteristics of the biological systems, but also by intrinsic dynamic properties of biological systems, including stability, transient-response, and controllability, which determine how the systems maintain their functions and performance under a broad range of random internal and external perturbations. As a proof of principle, we examine signal transduction pathways and genetic regulatory pathways as biological systems. We employ widely used state-space equations in systems science to model biological systems, and use expectation-maximization (EM) algorithms and Kalman filter to estimate the parameters in the models. We apply the developed state-space models to human fibroblasts obtained from the autoimmune fibrosing disease, scleroderma, and then perform dynamic analysis of partial TGF-beta pathway in both normal and scleroderma fibroblasts stimulated by silica. We find that TGF-beta pathway under perturbation of silica shows significant differences in dynamic properties between normal and scleroderma fibroblasts. Our findings may open a new avenue in exploring the functions of cells and mechanism operative in disease development.

Differential dynamic properties of scleroderma fibroblasts in response to perturbation of environmental stimuli.

Diseases are believed to arise from dysregulation of biological systems (pathways) perturbed by environmental triggers. Biological systems as a whole are not just the sum of their components, rather ever-changing, complex and dynamic systems over time in response to internal and external perturbation. In the past, biologists have mainly focused on studying either functions of isolated genes or steady-states of small biological pathways. However, it is systems dynamics that play an essential role in giving rise to cellular function/dysfunction which cause diseases, such as growth, differentiation, division and apoptosis. Biological phenomena of the entire organism are not only determined by steady-state characteristics of the biological systems, but also by intrinsic dynamic properties of biological systems, including stability, transient-response, and controllability, which determine how the systems maintain their functions and performance under a broad range of random internal and external perturbations. As a proof of principle, we examine signal transduction pathways and genetic regulatory pathways as biological systems. We employ widely used state-space equations in systems science to model biological systems, and use expectation-maximization (EM) algorithms and Kalman filter to estimate the parameters in the models. We apply the developed state-space models to human fibroblasts obtained from the autoimmune fibrosing disease, scleroderma, and then perform dynamic analysis of partial TGF-beta pathway in both normal and scleroderma fibroblasts stimulated by silica. We find that TGF-beta pathway under perturbation of silica shows significant differences in dynamic properties between normal and scleroderma fibroblasts. Our findings may open a new avenue in exploring the functions of cells and mechanism operative in disease development.

The care to share HIV disclosure study - the attitudes toward and beliefs about HIV disclosure among perinatally-infected HIV-positive youth and their caregivers

HIV incidence has not changed since the introduction of the pandemic. Daily 14,000 persons are infected with HIV and 25 to 50% of the HIV-infected population and subgroups respectively are estimated to be unaware of their HIV diagnosis. Perinatally-infected HIV-positive youth, aged 13-24 years, have survived unexpectedly into adulthood, have had unique HIV disclosure experiences and now face HIV disclosure issues of adulthood and perhaps parenthood. Despite new effective HIV therapies, no HIV prevention plan exists that has diminished the rate of new HIV infections. HIV stigma and lack of universal HIV reporting laws dissuade timely HIV disclosure. Missed HIV disclosure perpetuates HIV transmission and infection. Understanding the attitudes and beliefs of HIV disclosure among perinatally-infected HIV-positive youth and their caregivers may uncover reasons to HIV disclosure delays, avoidance and intentions. The Care to Share HIV Disclosure study was designed to identify the attitudes and beliefs of HIV disclosure among HIV-positve youth (aged 13-24 years), who were infected from birth and who knew their HIV diagnosis, along with their caregivers. Twenty-six participants (15 youth and 11 caregivers) completed the theory-based questionnaires of a 21-item multiple choice survey on HIV disclosure framed in the Theory of Reasoned Action and Theory of Planned Behavior and included an additional open-ended survey that applied the Transactional Model of Stress and Coping to address youth's and caregivers' HIV disclosure experiences. Youth were found to have a selective unfavorable HIV disclosure outcome when among referents of close friends. However youth did believe in HIV partner notification. For caregivers, it mattered who disclosed the HIV illness to the youth. HIV stigma was of concern based on the youths' tendency to believe in keeping HIV a secret and their caregivers' ambivalence to HIV secrecy. However, favorable HIV disclosure outcomes were identified for both youth and caregivers the potential for HIV disclosure: when seeking HIV knowledge, when around caregivers and close family and in situations of perceived controllability as when helping others learn about HIV. These findings unveil HIV disclosure attitudes and beliefs within this population and may reveal the attributes that may inhibit or promote HIV disclosure behaviors. HIV disclosure studies that address attitudes and beliefs among larger populations of youth and HIV-infected persons are necessary to identify effective individual, group and society approaches that would promote timely, responsible and meaningful HIV disclosure methods that promote a healthy identity and interrupt HIV transmission.^