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Full-Text Articles in Medicine and Health Sciences

The Gating Charge Should Not Be Estimated By Fitting A Two-State Model To A Q-V Curve, Francisco Bezanilla, Carlos A. Villalba-Galea Dec 2013

The Gating Charge Should Not Be Estimated By Fitting A Two-State Model To A Q-V Curve, Francisco Bezanilla, Carlos A. Villalba-Galea

School of Pharmacy Faculty Articles

The voltage dependence of charges in voltage-sensitive proteins, typically displayed as charge versus voltage (Q-V) curves, is often quantified by fitting it to a simple two-state Boltzmann function. This procedure overlooks the fact that the fitted parameters, including the total charge, may be incorrect if the charge is moving in multiple steps. We present here the derivation of a general formulation for Q-V curves from multistate sequential models, including the case of infinite number of states. We demonstrate that the commonly used method to estimate the charge per molecule using a simple Boltzmann fit is not only inadequate, but in …


Evidence For Finely-Regulated Asynchronous Growth Of Toxoplasma Gondii Cysts Based On Data-Driven Model Selection, Adam M. Sullivan, Xiaopeng Zhao, Yasuhiro Suzuki, Eri Ochiai, Stephen Crutcher, Michael A. Gilchrist Nov 2013

Evidence For Finely-Regulated Asynchronous Growth Of Toxoplasma Gondii Cysts Based On Data-Driven Model Selection, Adam M. Sullivan, Xiaopeng Zhao, Yasuhiro Suzuki, Eri Ochiai, Stephen Crutcher, Michael A. Gilchrist

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Toxoplasma gondii establishes a chronic infection by forming cysts preferentially in the brain. This chronic infection is one of the most common parasitic infections in humans and can be reactivated to develop life-threatening toxoplasmic encephalitis in immunocompromised patients. Host-pathogen interactions during the chronic infection include growth of the cysts and their removal by both natural rupture and elimination by the immune system. Analyzing these interactions is important for understanding the pathogenesis of this common infection. We developed a differential equation framework of cyst growth and employed Akaike Information Criteria (AIC) to determine the growth and removal functions that best describe …


Sensing Charges Of The Ciona Intestinalis Voltage-Sensing Phosphatase, Carlos A. Villalba-Galea, Ludivine Frezza, Walter Sandtner, Francisco Bezanilla Nov 2013

Sensing Charges Of The Ciona Intestinalis Voltage-Sensing Phosphatase, Carlos A. Villalba-Galea, Ludivine Frezza, Walter Sandtner, Francisco Bezanilla

School of Pharmacy Faculty Articles

Voltage control over enzymatic activity in voltage-sensitive phosphatases (VSPs) is conferred by a voltage-sensing domain (VSD) located in the N terminus. These VSDs are constituted by four putative transmembrane segments (S1 to S4) resembling those found in voltage-gated ion channels. The putative fourth segment (S4) of the VSD contains positive residues that likely function as voltage-sensing elements. To study in detail how these residues sense the plasma membrane potential, we have focused on five arginines in the S4 segment of the Ciona intestinalis VSP (Ci-VSP). After implementing a histidine scan, here we show that four arginine-to-histidine mutants, namely R223H to …


The Older Patient, The Doctor And The Trainee: Patients' Attitudes And Implications For Models Of Care, Andrew Bonney, Sandra Jones, Donald Iverson Jun 2013

The Older Patient, The Doctor And The Trainee: Patients' Attitudes And Implications For Models Of Care, Andrew Bonney, Sandra Jones, Donald Iverson

Sandra Jones

Aims & rationale/Objectives Population ageing poses major challenges for health systems. Additionally, training future general practitioners in the management of older and chronically ill patients is potentially hampered by the reluctance of these patients to consult trainees for chronic care. This paper reports a cross-sectional study investigating the attitudes of older patients to trainees, to inform strategies to improve older patient-trainee interaction. Methods The survey instrument was distributed to 1900 patients aged 60 and over from 38 training practices from five Australian states using a stratified, randomised cluster sampling process. Generalised estimating equation models were used for analysis. Principal findings …


Are Pre-Adolescent Girls' Magazines Providing Age-Appropriate Role Models?, Belinda S. Fabrianesi, Sandra C. Jones, Amanda Reid Jun 2013

Are Pre-Adolescent Girls' Magazines Providing Age-Appropriate Role Models?, Belinda S. Fabrianesi, Sandra C. Jones, Amanda Reid

Sandra Jones

Purpose – Repeated exposure to unrealistic notions of female beauty and body shapes, and limited gender stereotypes, may result in the internalization of those standards by pre-adolescent girls. The purpose of this content analysis is to examine the celebrity role models to whom young girls are exposed via magazines specifically targeted at the “tween” audience. Female celebrities are contrasted with those in magazines targeted at older adolescent girls. Design/methodology/approach – Two pre-adolescent girls’ magazines, Total Girl and Barbie, and two adolescent girls’ magazines, Dolly and Girlfriend, were analyzed for the first six months of 2005. All photos (including advertising images) …


The Role Of Indoleamine 2,3-Dioxygenase In Lp-Bpm5 Murine Retroviral Disease Progression, Megan A. O'Connor, William R. Green May 2013

The Role Of Indoleamine 2,3-Dioxygenase In Lp-Bpm5 Murine Retroviral Disease Progression, Megan A. O'Connor, William R. Green

Dartmouth Scholarship

Indoleamine 2,3-dioxygenase (IDO) is an immunomodulatory intracellular enzyme involved in tryptophan degradation. IDO is induced during cancer and microbial infections by cytokines, ligation of co-stimulatory molecules and/or activation of pattern recognition receptors, ultimately leading to modulation of the immune response. LP-BM5 murine retroviral infection induces murine AIDS (MAIDS), which is characterized by profound and broad immunosuppression of T- and B-cell responses. Our lab has previously described multiple mechanisms regulating the development of immunodeficiency of LP-BM5-induced disease, including Programmed Death 1 (PD-1), IL-10, and T-regulatory (Treg) cells. Immunosuppressive roles of IDO have been demonstrated in other retroviral models, suggesting a possible …