The Check-Up, July 2010

An update on issues and ideas related to health reform in Iowa Second Story Headline The Check-Up is a monthly health care reform newsletter designed to keep interested Iowans up to date on the progress of health reform initiatives assigned to IDPH.

Prediction of difficult intubation with advanced face recognition techniques: a preliminary study

Introduction: Difficult tracheal intubation remains a constant and significant source of morbidity and mortality in anaesthetic practice. Insufficient airway assessment in the preoperative period continues to be a major cause of unanticipated difficult intubation. Although many risk factors have already been identified, preoperative airway evaluation is not always regarded as a standard procedure and the respective weight of each risk factor remains unclear. Moreover the predictive scores available are not sensitive, moderately specific and often operator-dependant. In order to improve the preoperative detection of patients at risk for difficult intubation, we developed a system for automated and objective evaluation of morphologic criteria of the face and neck using video recordings and advanced techniques borrowed from face recognition. Method and results: Frontal video sequences were recorded in 5 healthy volunteers. During the video recording, subjects were requested to perform maximal flexion-extension of the neck and to open wide the mouth with tongue pulled out. A robust and real-time face tracking system was then applied, allowing to automatically identify and map a grid of 55 control points on the face, which were tracked during head motion. These points located important features of the face, such as the eyebrows, the nose, the contours of the eyes and mouth, and the external contours, including the chin. Moreover, based on this face tracking, the orientation of the head could also be estimated at each frame of the video sequence. Thus, we could infer for each frame the pitch angle of the head pose (related to the vertical rotation of the head) and obtain the degree of head extension. Morphological criteria used in the most frequent cited predictive scores were also extracted, such as mouth opening, degree of visibility of the uvula or thyreo-mental distance. Discussion and conclusion: Preliminary results suggest the high feasibility of the technique. The next step will be the application of the same automated and objective evaluation to patients who will undergo tracheal intubation. The difficulties related to intubation will be then correlated to the biometric characteristics of the patients. The objective in mind is to analyze the biometrics data with artificial intelligence algorithms to build a highly sensitive and specific predictive test.

The Check-Up, August-September 2010

An update on issues and ideas related to health reform in Iowa Second Story Headline The Check-Up is a monthly health care reform newsletter designed to keep interested Iowans up to date on the progress of health reform initiatives assigned to IDPH.

The Check-Up, October-November 2010

An update on issues and ideas related to health reform in Iowa Second Story Headline The Check-Up is a monthly health care reform newsletter designed to keep interested Iowans up to date on the progress of health reform initiatives assigned to IDPH.

The Check-Up, December 2010-January 2011

An update on issues and ideas related to health reform in Iowa Second Story Headline The Check-Up is a monthly health care reform newsletter designed to keep interested Iowans up to date on the progress of health reform initiatives assigned to IDPH.

The Check-Up, May 2009

An update on issues and ideas related to health reform in Iowa Second Story Headline The Check-Up is a monthly health care reform newsletter designed to keep interested Iowans up to date on the progress of health reform initiatives assigned to IDPH.

The Check-Up, August 2009

An update on issues and ideas related to health reform in Iowa Second Story Headline The Check-Up is a monthly health care reform newsletter designed to keep interested Iowans up to date on the progress of health reform initiatives assigned to IDPH.

The Check-Up, September 2009

An update on issues and ideas related to health reform in Iowa Second Story Headline The Check-Up is a monthly health care reform newsletter designed to keep interested Iowans up to date on the progress of health reform initiatives assigned to IDPH.

The Check-Up, October 2009

An update on issues and ideas related to health reform in Iowa Second Story Headline The Check-Up is a monthly health care reform newsletter designed to keep interested Iowans up to date on the progress of health reform initiatives assigned to IDPH.

The Check-Up, November 2009

An update on issues and ideas related to health reform in Iowa Second Story Headline The Check-Up is a monthly health care reform newsletter designed to keep interested Iowans up to date on the progress of health reform initiatives assigned to IDPH.

The Check-Up, December 2009

An update on issues and ideas related to health reform in Iowa Second Story Headline The Check-Up is a monthly health care reform newsletter designed to keep interested Iowans up to date on the progress of health reform initiatives assigned to IDPH.

Pattern recognition ecological niche models fit to presence-only and presence-absence data

1. Identifying the boundary of a species' niche from observational and environmental data is a common problem in ecology and conservation biology and a variety of techniques have been developed or applied to model niches and predict distributions. Here, we examine the performance of some pattern-recognition methods as ecological niche models (ENMs). Particularly, one-class pattern recognition is a flexible and seldom used methodology for modelling ecological niches and distributions from presence-only data. The development of one-class methods that perform comparably to two-class methods (for presence/absence data) would remove modelling decisions about sampling pseudo-absences or background data points when absence points are unavailable. 2. We studied nine methods for one-class classification and seven methods for two-class classification (five common to both), all primarily used in pattern recognition and therefore not common in species distribution and ecological niche modelling, across a set of 106 mountain plant species for which presence-absence data was available. We assessed accuracy using standard metrics and compared trade-offs in omission and commission errors between classification groups as well as effects of prevalence and spatial autocorrelation on accuracy. 3. One-class models fit to presence-only data were comparable to two-class models fit to presence-absence data when performance was evaluated with a measure weighting omission and commission errors equally. One-class models were superior for reducing omission errors (i.e. yielding higher sensitivity), and two-classes models were superior for reducing commission errors (i.e. yielding higher specificity). For these methods, spatial autocorrelation was only influential when prevalence was low. 4. These results differ from previous efforts to evaluate alternative modelling approaches to build ENM and are particularly noteworthy because data are from exhaustively sampled populations minimizing false absence records. Accurate, transferable models of species' ecological niches and distributions are needed to advance ecological research and are crucial for effective environmental planning and conservation; the pattern-recognition approaches studied here show good potential for future modelling studies. This study also provides an introduction to promising methods for ecological modelling inherited from the pattern-recognition discipline.

Distinct sets of alphabeta TCRs confer similar recognition of tumor antigen NY-ESO-1157-165 by interacting with its central Met/Trp residues.

Naturally acquired immune responses against human cancers often include CD8(+) T cells specific for the cancer testis antigen NY-ESO-1. Here, we studied T cell receptor (TCR) primary structure and function of 605 HLA-A*0201/NY-ESO-1(157-165)-specific CD8 T cell clones derived from five melanoma patients. We show that an important proportion of tumor-reactive T cells preferentially use TCR AV3S1/BV8S2 chains, with remarkably conserved CDR3 amino acid motifs and lengths in both chains. All remaining T cell clones belong to two additional sets expressing BV1 or BV13 TCRs, associated with alpha-chains with highly diverse VJ usage, CDR3 amino acid sequence, and length. Yet, all T cell clonotypes recognize tumor antigen with similar functional avidity. Two residues, Met-160 and Trp-161, located in the middle region of the NY-ESO-1(157-165) peptide, are critical for recognition by most of the T cell clonotypes. Collectively, our data show that a large number of alphabeta TCRs, belonging to three distinct sets (AVx/BV1, AV3/BV8, AVx/BV13) bind pMHC with equal antigen sensitivity and recognize the same peptide motif. Finally, this in-depth study of recognition of a self-antigen suggests that in part similar biophysical mechanisms shape TCR repertoires toward foreign and self-antigens.

The Check-Up, February-March 2011

An update on issues and ideas related to health reform in Iowa Second Story Headline The Check-Up is a monthly health care reform newsletter designed to keep interested Iowans up to date on the progress of health reform initiatives assigned to IDPH.

The Check-Up, April-May 2011

An update on issues and ideas related to health reform in Iowa Second Story Headline The Check-Up is a monthly health care reform newsletter designed to keep interested Iowans up to date on the progress of health reform initiatives assigned to IDPH.