Estimation of chest wall motion by surface measurements only allows one-dimensional measurements of the chest wall. We have assessed on optical reflectance system (OR), which tracks reflective markers in three dimensions (3-D) for respiratory use. We used 86 (6-mm-diameter) hemispherical reflective markers arranged circumferentially on the chest wall in seven rows between the sternal notch and the anterior superior iliac crest in two normal standing subjects. We calculated the volume of the entire chest wall and compared inspired and expired volumes with volumes obtained by spirometry. Marker positions were recorded by four TV cameras; two were 4 m in front of and two were 4 m behind the subject. The TV signals were sampled at 100 Hz and combined with grid calibration parameters on a personal computer to obtain the 3-D coordinates of the markers. Chest wall surfaces were reconstructed by triangulation through the point data, and chest wall volume was calculated. During tidal breathing and vital capacity maneuvers and during CO2-stimulated hyperpnea, there was a very close correlation of the lung volumes (VL) estimated by spirometry [VL(SP)] and OR [VL(OR)]. Regression equations of VL(OR) (y) vs. VL(SP) (x, BTPS in liters) for the two subjects were given by y = 1.01x-0.01 (r = 0.996) and y = 0.96x + 0.03 (r = 0.997), and by y = 1.04x + 0.25 (r = 0.97) and y = 0.98x + 0.14 (r = 0.95) for the two maneuvers, respectively. We conclude spirometric volumes can be estimated very accurately and directly from chest wall surface markers, and we speculate that OR may be usefully applied to calculations of chest wall shape, regional volumes, and motion analysis.

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A method for kinematic analysis of chest wall motion is presented, based on a television-image processor that allows a three-dimensional assessment of volume change of the trunk by automatically computing the coordinates of several passive markers placed on relevant landmarks of the thorax and abdomen. The parallel computation used for the image processing allows for a real time recognition of the passive markers with the necessary accuracy. A geometric model also allows the online computation of the contribution to the chest volume by the different parts. For this purpose, the model presented here is based on 54 tetrahedrons that can be grouped into 9 compartments and 3 sections representing 1) upper thorax (mainly reflecting the action of neck and parasternal muscles and the effect of pleural pressure), 2) lower thorax (mainly reflecting the action of diaphragm and the effect of pleural and abdominal pressure), and 3) abdomen (mainly reflecting the actions of diaphragm and abdominal muscles). By this model, the volume can also be split into three vertical sections pointing out asymmetries between the right and left sides. The method is noninvasive, nonionizing, and leaves the subject maximum freedom of movement during the test, thus being suitable for routine clinical analysis. The monitoring of the subject can be prolonged in time and can be performed in different postures: standing, sitting, and supine. The method was tested on 12 healthy subjects showing its good accuracy, reliability, and reproducibility.

No abstract

Inflammation and immunity are linked to intestinal adenoma (IA) and colorectal cancer (CRC) development. The gut microbiota is associated with CRC risk. Epithelial barrier dysfunction can occur, possibly leading to increased intestinal permeability in CRC patients. We conducted a case-control study including 100 incident histologically confirmed CRC cases, and 100 IA and 100 healthy subjects, matched to cases by center, sex and age. We performed 16S rRNA gene analysis of blood and applied conditional logistic regression. Further analyses were based on negative binomial distribution normalization and Random Forest algorithm. We found an overrepresentation of blood 16S rRNA gene copies in colon cancer as compared to tumor-free controls. For high levels of gene copies, community diversity was higher in colon cancer cases than controls. Bacterial taxa and operational taxonomic unit abundances were different between groups and were able to predict CRC with an accuracy of 0.70. Our data support the hypothesis of a higher passage of bacteria from gastrointestinal tract to bloodstream in colon cancer. This result can be applied on non-invasive diagnostic tests for colon cancer control.