BoneMorphing versus freehand localization of anatomical landmarks: consequences for the reproducibility of implant positioning in total knee arthroplasty.

OBJECTIVE: This study analyzed the influence of the acquisition method in image-free computer-assisted total knee arthroplasty (CAS-TKA), and the reproducibility of implant planning using BoneMorphing, a 3D morphometric model obtained by a 3D-to-3D elastic registration of statistical models to sparse point clouds acquired directly on the bone surface with a pointer. MATERIALS AND METHODS: Five surgeons (one expert, four trainees) each performed a CAS-TKA hybrid protocol based on morphometric models and landmarks on a cadaveric knee 10 times. In addition, several additional landmarks were digitized during each acquisition. The reproducibility of the implant positioning and sizing, as determined by an implant planning algorithm with morphometric models, was compared to direct digitization accuracy. RESULTS: Femoral and tibial implant positioning parameters with the hybrid protocol resulted in intra-surgeon standard deviations (SDs) of less than+/-1.4 degrees for rotation and 1.9 mm for translation for all surgeons in all directions except for tibial axial rotation (the only parameter determined by a digitized landmark and not recomputed in the 3D model). The variability in individual landmark digitization varied from 2 to 5 mm SD for certain landmarks, with ranges of 15-25 mm across all surgeons. The comparison study showed an improvement in femoral rotation reproducibility with the morphometric model when using the posterior condylar axis. Tibial implant reproducibility for each method was comparable, with the morphometric model giving better results in well-digitized areas such as the tibial plateau. CONCLUSION: A CAS-TKA protocol based on a deformed statistical model offers reproducible implant positioning. Some landmarks, such as distal condyles, show sufficient reproducibility in the direction of interest, while others, such as the anterior tibial tubercle, can lead to hazardous implant positioning. This should be taken into consideration when designing a CAS-TKA system with bony landmarks. In areas where a sufficient number of points have been digitized with good coverage, such as on the distal and posterior femoral condyles or the tibial plateau areas, the information derived from the 3D model is more accurate and reproducible than that derived from digitization. Good training and a guiding user interface are essential to guarantee coverage quality.     

First analysis of the proteome in two nematomorph species, Paragordius tricuspidatus (Chordodidae) and Spinochordodes tellinii (Spinochordodidae).

The proteome of most parasite species is currently unknown. Hairworms (Nematomorpha), 300 species distributed around the world, are parasitic in arthropods (mainly terrestrial species) when juveniles, but they are free-living in aquatic environments when adult. Most aspects of their systematics and biology are currently unknown. The aim of this paper was (i) to report a novel and reproducible protocol for the analysis of the proteome of hairworms using two-dimensional gel electrophoresis (2-DGE) and mass spectrometry (matrix laser desorption ionization-time of flight mass spectrometry (MALDI-TOF)) and (ii) to determine the level of proteomic divergence between two sympatric but taxonomically unrelated nematomorph species in the adult stage, Paragordius tricuspidatus Dufour (Nematomorpha, Gordiidae) and Spinochordodes tellinii Camerano (Nematomorpha, Gordiidae). In total, 689 protein spots were observed for P. tricuspidatus, 575 for S. tellinii. Only 36.2% spots were shared between the two species. Quantitative analysis of the proteins which are common to both parasite species reveals substantial differences in the pattern of protein expression. These results suggest a rapid evolutionary divergence between these two nematomorph families. Also, to test the value of our MALDI-TOF protocol, we used Actin-2 (Act-2), a protein highly conserved in the course of evolution. Peptide mass fingerprint (PMF) data obtained for Act-2 of P. tricuspidatus and S. tellinii suggest a very high homology with Act-2 of different worms species belonging to the Bilateria phylum (Annelida and Nematoda) and more specifically to Lumbricus terrestris (Annelida, Lumbricidae) and Caenorhabditis elegans (Nematoda, Rhabditidae). We discuss our results in relationship with current ideas concerning the use of proteomics in systematics.     

Pre-adaptation, adaptation and de-adaptation to high altitude in humans: hormonal and biochemical changes at sea level

High altitude residence is known to modify body biochemistry and hormone status. However, the effects of such a sojourn on these status observed at sea level both immediately and later after return are not as well established as are the effects of an intermittent acclimation. The aim of this study was therefore to investigate these changes. To achieve our objectives, nine subjects received intermittent acclimation at low pressure in a barometric chamber (8?h daily for 5 days, day 1 at 4500 m, day 5 at 8500 m) before an expedition to the Himalayas. Hormonal and biochemical changes were studied using samples of venous blood taken at sea level before and after acclimation, after return from the expedition and 1 and 2 months after descent. Concentrations of thyroid hormones, adrenaline, noradrenaline (NA), hormones of hydromineral metabolism (aldosterone, renin, arginine vasopressin, atrial natriuretic peptide) as well as prolactin, cortisol, insulin and endothelin 1 were measured. Biochemical measurements made were plasma osmolality, and concentrations of glucose, total cholesterol, total proteins, pre-albumin, transferrin, complement 3C, apolipoproteins A₁ and B and serum iron. Acclimation induced no alteration in hormone (except for NA with increases of about 1.5, fold P<0.05) and biochemistry data. After the expedition, hormone responses were characterized by a higher total triidothyronine concentration (+18%, P<0.05) while other hormones did not vary. A linear relationship was found between thyroid-stimulating-hormone and body mass changes after the expedition (r=0.67, P<0.05). The observed increased concentrations of plasma proteins and total cholesterol (P<0.05) could be related to the restoration of lean body mass. At 1 and 2 months after return, no changes in hormones were observed but a significant decrease in transferrin concentration was noticed. The higher serum iron concentration reported after 1 month (P<0.05) could have been the result of a physiological haemolysis. It was concluded that both acclimation and the expedition in the Himalayas affected hormone status and body biochemistry status even though the observed changes were slight and rapidly reversed.     

Further characterization of the discriminative stimulus effects of buspirone using monoamine agonists and antagonists in the pigeon

White Carneau pigeons were trained to discriminate 1.0 mg/kg buspirone from saline when key pecking was maintained under a fixed-ratio 30 schedule of food presentation. Buspirone (0.3-10.0 mg/kg), the serotonin 1A (5-HT(1A)) agonist 8-OH-DPAT (0.1-1mg/kg), the buspirone analog BMY 7378 (3.0-5.6mg/kg), the mixed 5-HT(1A/1B) agonist RU 24969 (3.0-10.0mg/kg) and the 5-HT(1A) agonist spiroxatrine (0.1-1.0mg/kg) occasioned at least 80% buspirone-appropriate responding in all subjects tested. Administration of the 5-HT(1B) agonist (TFMPP 0.1-10.0mg/kg) or the 5-HT(3) antagonist (MDL 72222 (3.0-17.0mg/kg) resulted in primarily saline-key responding. The dopamine receptor antagonist chlorpromazine (1.0-17.0mg/kg), the specific D-2 receptor antagonist eticlopride (0.03-0.56mg/kg), the noradrenergic alpha-2 antagonist yohimbine (0.1-1.0mg/kg), the alpha-2 agonist clonidine (0.003-0.10mg/kg) and (+/-) and (-) propranolol (3.0-30.0mg/kg) all produced primarily saline-appropriate responding. Coadministration of the beta-adrenergic agonist isoproterenol (1.0-5.6mg/kg) or the 5-HT(1A) partial agonist BMY 7378 (0.01-10.0mg/kg) with 1.0mg/kg buspirone did not block the discriminative stimulus effects of buspirone. However, 3.0-10.0mg/kg BMY 7378, in combination with a lower dose of buspirone (0.3mg/kg) decreased drug-key responding to approximately 50%. Results from the present study suggest that (1) the discriminative stimulus effects of buspirone, 8-OH-DPAT, BMY 7378, RU 24969 and spiroxatrine are mediated through the 5-HT(1A) receptor; (2) buspirone's discriminative stimulus effects do not interact with the noradrenergic or dopaminergic system; and 3) under this procedure BMY 7378 was a partial agonist at 5-HT(1A) receptors.     

The TL MHC class Ib molecule has only marginal effects on the activation, survival and trafficking of mouse small intestinal intraepithelial lymphocytes

Thymus leukemia antigen (TL) is an MHC class Ib molecule that is highly conserved in rats and mice with no obvious human homolog. TL is expressed in mouse small intestinal epithelial cells and is known to interact with CD8alphaalpha homodimers, which are expressed by intraepithelial lymphocytes (IELs), some other T cell subsets and some non-T cells such as a subset of dendritic cells. We show here that TL is abundantly expressed on the basolateral surface of mouse small intestinal epithelial cells and that expression is abrogated in beta2m-/- mice but unaffected in TCR-/- mice or CD8alpha chain-/- mice. We demonstrate that the interaction between TL and CD8alphaalpha is not necessary for IEL survival in vitro or in vivo and does not modulate IEL trafficking in vivo. TL co-stimulation of alpha-CD3 antibody-activated IELs resulted in modestly enhanced production of IFN-gamma in one subset of IELs. The lack of effect on IEL survival and trafficking and the modest effect on IFN-gamma production suggest that the functional consequences of TL interaction with CD8alphaalpha as well as the more general biological role of TL in mucosal immunity remains to be discovered.     

Is one assessment enough? Patterns of helping alliance development and outcome

Early therapeutic alliance is usually measured by the rating of a single session (between the third and the fifth sessions). However, there is a strong argument in favor of viewing early alliance as a developing process. This study examined the relationship between patient's rating of the helping alliance (HAq) at each session and therapy outcome. This comparison was repeated using patterns of alliance over the course of treatment. Patterns of therapeutic alliance development were detected by clustering ratings of a sample of N = 70 outpatients across four sessions of very brief psychotherapeutic intervention. Cluster analysis revealed two main patterns (shapes) of alliance development: (i) stable alliance, and (ii) linear growth pattern. These patterns are more predictive of symptom improvement and social adjustment than single ratings, whereas single ratings measuring the strength of alliance are more correlated with patient's satisfaction. Copyright © 2004 John Wiley & Sons, Ltd.