Fetal MRI as complement to US in the diagnosis and characterization of anomalies of the genito-urinary tract.

The purpose of this study is to compare the accuracy of prenatal ultrasound (US) and prenatal magnetic resonance imaging (MRI) in the diagnosis and characterization of congenital abnormalities of the genito-urinary tract and to determine if the additional information obtained by MRI may influence the management of the fetus. We retrospectively evaluate 15 cases of congenital genito-urinary tract anomalies detected by prenatal US and with echographic inconclusive diagnosis. We compare the MRI findings with the US findings and the final diagnosis, obtained from neonatal outcomes, imaging studies and pathology records. Fetal US diagnosis was correct in 9 cases (60%) and MRI in 13 cases (86.7%). Prenatal MRI revealed additional information to US in 9 cases (60%), which modified the initial US diagnosis in 5 cases (33.3%) and changed the therapeutic approach in 5 fetuses (33.3%). Fetal MRI was better than US in cases of oligoamnios and in fetuses with genito-urinary pathology concerning the pelvic and perineum region. We believe that MRI should be considered as a complementary diagnostic method in cases of echographic suspicion of congenital pathology of the genito-urinary tract and inconclusive prenatal US.

The fixation of locally beneficial alleles in a metapopulation.

Extinction, recolonization, and local adaptation are common in natural spatially structured populations. Understanding their effect upon genetic variation is important for systems such as genetically modified organism management or avoidance of drug resistance. Theoretical studies on the effect of extinction and recolonization upon genetic variance started appearing in the 1970s, but the role of local adaptation still has no good theoretical basis. Here we develop a model of a haploid species in a metapopulation in which a locally adapted beneficial allele is introduced. We study the effect of different spatial patterns of local adaptation, and different metapopulation dynamics, upon the fixation probability of the beneficial allele. Controlling for the average selection pressure, we find that a small area of positive selection can significantly increase the global probability of fixation. However, local adaptation becomes less important as extinction rate increases. Deme extinction and recolonization have a spatial smoothing effect that effectively reduces spatial variation in fitness.

The implications of alternative splicing in the ENCODE protein complement.

Alternative premessenger RNA splicing enables genes to generate more than one gene product. Splicing events that occur within protein coding regions have the potential to alter the biological function of the expressed protein and even to create new protein functions. Alternative splicing has been suggested as one explanation for the discrepancy between the number of human genes and functional complexity. Here, we carry out a detailed study of the alternatively spliced gene products annotated in the ENCODE pilot project. We find that alternative splicing in human genes is more frequent than has commonly been suggested, and we demonstrate that many of the potential alternative gene products will have markedly different structure and function from their constitutively spliced counterparts. For the vast majority of these alternative isoforms, little evidence exists to suggest they have a role as functional proteins, and it seems unlikely that the spectrum of conventional enzymatic or structural functions can be substantially extended through alternative splicing.

Formaldehyde-fixation of platelets for flow cytometric measurement of phosphatidylserine exposure is feasible.

Strong platelet activation results in a redistribution of negatively charged phospholipids from the cytosolic to the outer leaflet of the cellular membrane. Annexin V has a high affinity to negatively charged phospholipids and can be used to identify procoagulant platelets. Formaldehyde fixation can cause factitious Annexin V binding. Our aim was to evaluate a method for fixing platelets avoiding additional Annexin V binding. We induced expression of negatively charged phospholipids on the surface of a fraction of platelets by combined activation with convulxin and thrombin in the presence of Annexin V-fluorescein isothiocyanate and calcium. Aliquots of resting and activated platelets were fixed with a low concentration, calcium-free formaldehyde solution. Both native platelets and fixed platelets were analyzed by flow cytometry immediately and after a 24-h storage at 4°C. We observed that the percentage of Annexin V positive resting platelets ranged from 1.5 to 9.3% for the native samples and from 0.4 to 12.8% for the fixed samples (P=0.706, paired t-test). The amount of Annexin V positive convulxin/thrombin activated platelets varied from 12.9 to 35.4% without fixation and from 15.3 to 36.3% after formalin fixation (P=0.450). After a 24-h storage at 4°C, Annexin V positive platelets significantly increased both in the resting and in the convulxin/thrombin activated samples of native platelets (both P<0.001), while results for formalin fixed platelets did not differ from baseline values (P=0.318 for resting fixed platelets; P=0.673 for activated fixed platelets). We conclude that platelet fixation with a low concentration, calcium-free formaldehyde solution does not alter the proportion of Annexin V positive platelets. This method can be used to investigate properties of procoagulant platelets by multicolor flow-cytometric analysis requiring fixation steps.

Evaluation of the potential use of trabecular bone score to complement bone mineral density in the diagnosis of osteoporosis: a preliminary spine BMD-matched, case-control study.

The trabecular bone score (TBS) is a new parameter that is determined from gray-level analysis of dual-energy X-ray absorptiometry (DXA) images. It relies on the mean thickness and volume fraction of trabecular bone microarchitecture. This was a preliminary case-control study to evaluate the potential diagnostic value of TBS as a complement to bone mineral density (BMD), by comparing postmenopausal women with and without fractures. The sample consisted of 45 women with osteoporotic fractures (5 hip fractures, 20 vertebral fractures, and 20 other types of fracture) and 155 women without a fracture. Stratification was performed, taking into account each type of fracture (except hip), and women with and without fractures were matched for age and spine BMD. BMD and TBS were measured at the total spine. TBS measured at the total spine revealed a significant difference between the fracture and age- and spine BMD-matched nonfracture group, when considering all types of fractures and vertebral fractures. In these cases, the diagnostic value of the combination of BMD and TBS likely will be higher compared with that of BMD alone. TBS, as evaluated from standard DXA scans directly, potentially complements BMD in the detection of osteoporotic fractures. Prospective studies are necessary to fully evaluate the potential role of TBS as a complementary risk factor for fracture.

Fast liver catabolism of C1q in patients with paraproteinaemia and depletion of the classical pathway of complement.

The main clinical features in four patients with IgG1k paraproteinaemia and acquired complement deficiency included xanthomatous skin lesions (in three), panniculitis (in three) and hepatitis (in two). Hypocomplementaemia concerned the early classical pathway components--in particular C1q. Metabolic studies employing 125I-C1q revealed a much faster catabolism of this protein in the four patients than in five normal controls and three patients with cryoglobulinaemia (mean fractional catabolic rates respectively: 23.35%/h; 1.44%/h; 5.84%/h). Various experiments were designed to characterize the mechanism of the hypocomplementaemia: the patients' serum, purified paraprotein, blood cells, bone marrow cells, or xanthomatous skin lesions did not produce significant complement activation or C1q binding. When three of the patients (two with panniculitis and hepatitis) were injected with 123I-C1q, sequential gamma-camera imaging demonstrated rapid accumulation of the radionuclide in the liver, suggesting that complement activation takes place in the liver where it could produce damage.

Tension-band wiring of olecranon fractures - Biomechanical analysis of different fixation techniques

Tension-band wiring is a recognised standard treatment for fixation of olecranon fractures. The classical operation technique is well known and widespread among the orthopaedic surgeons. Nevertheless complications like K-wire migration or skin perforation and difficult technical as well as anatomical prerequisites require better-adapted operation fixation methods. In older female patients a cut through of the Kirschner wires with concomitant secondary displacement was observed. We intent to develop a new, better adapted operation technique for olecranon fractures in the old patients, in order to decrease complications and follow-up procedures. In this study we compare two different K-wire positions: 10 models of the classical AO tension-banding to 10 models with adapted K-wire insertion. In this group the K-wire passes from the tip of the olecranon to the posterior cortical of the distal fragment of the ulna. We tested maximal failure load, maximal opening angle as well as maximal work to achieve maximal force. In either technique we were able to determine different variables: a maximal failure load of more than 600N (p = 0.94) for both fixation methods and a maximal opening angle for both techniques of about 10° (p = 0.86). To achieve the maximal force our modified technique required a slightly increased work (p = 0.16). In this study no statistical significant differences between the two fixation techniques was shown. This leads to the conclusion that the modified version is comparable to the classical operation technique considering the stability, but due to the adaption of the angle in the modified procedure, less lesions of neurovascular structures on the volar side can be expected. To support our findings cadaver studies are needed for further investigations.

Breast cancer and melanoma cell line identification by FTIR imaging after formalin-fixation and paraffin-embedding.

Over the past few decades, Fourier transform infrared (FTIR) spectroscopy coupled to microscopy has been recognized as an emerging and potentially powerful tool in cancer research and diagnosis. For this purpose, histological analyses performed by pathologists are mostly carried out on biopsied tissue that undergoes the formalin-fixation and paraffin-embedding (FFPE) procedure. This processing method ensures an optimal and permanent preservation of the samples, making FFPE-archived tissue an extremely valuable source for retrospective studies. Nevertheless, as highlighted by previous studies, this fixation procedure significantly changes the principal constituents of cells, resulting in important effects on their infrared (IR) spectrum. Despite the chemical and spectral influence of FFPE processing, some studies demonstrate that FTIR imaging allows precise identification of the different cell types present in biopsied tissue, indicating that the FFPE process preserves spectral differences between distinct cell types. In this study, we investigated whether this is also the case for closely related cell lines. We analyzed spectra from 8 cancerous epithelial cell lines: 4 breast cancer cell lines and 4 melanoma cell lines. For each cell line, we harvested cells at subconfluence and divided them into two sets. We first tested the "original" capability of FTIR imaging to identify these closely related cell lines on cells just dried on BaF2 slides. We then repeated the test after submitting the cells to the FFPE procedure. Our results show that the IR spectra of FFPE processed cancerous cell lines undergo small but significant changes due to the treatment. The spectral modifications were interpreted as a potential decrease in the phospholipid content and protein denaturation, in line with the scientific literature on the topic. Nevertheless, unsupervised analyses showed that spectral proximities and distances between closely related cell lines were mostly, but not entirely, conserved after FFPE processing. Finally, PLS-DA statistical analyses highlighted that closely related cell lines are still successfully identified and efficiently distinguished by FTIR spectroscopy after FFPE treatment. This last result paves the way towards identification and characterization of cellular subtypes on FFPE tissue sections by FTIR imaging, indicating that this analysis technique could become a potential useful tool in cancer research.

Le facteur D du complément: toxine urémique [Factor D of complement: Uremic toxin?].

Factor D is an essential enzyme of the alternative pathway of complement. Its catabolism is mainly renal. The concentration of factor D increases with renal failure, and is approximately 10-fold higher in patients with end-stage renal disease. The accumulation of factor D is responsible for an enhancement of alternative pathway activation. Whether this excess of factor D has pathophysiological consequences remains to be determined, however, complement activation might participate in adverse effects during hemodialysis and in the progression of renal injury.

Increased titers of anti-Saccharomyces cerevisiae antibodies in Crohn's disease patients with reduced H-ficolin levels but normal MASP-2 activity.

BACKGROUND AND AIMS: Mannan-binding lectin (MBL) and ficolins are microbial pattern recognition molecules that activate the lectin pathway of complement. We previously reported the association of MBL deficiency with anti-Saccharomyces cerevisiae antibodies (ASCA) in patients with Crohn's disease (CD). However, ASCA are also frequently found in MBL-proficient CD patients. Here we addressed expression/function of ficolins and MBL-associated serine protease-2 (MASP-2) regarding potential association with ASCA. METHODS: ASCA titers and MBL, ficolin and MASP-2 concentrations were determined by ELISA in the serum of patients with CD, ulcerative colitis (UC), and in healthy controls. MASP-2 activity was determined by measuring complement C4b-fixation. Anti-MBL autoantibodies were detected by ELISA. RESULTS: In CD and UC patients, L-ficolin concentrations were significantly higher compared to healthy controls (p<0.001 and p=0.029). In contrast, H-ficolin concentrations were slightly reduced in CD and UC compared to healthy controls (p=0.037 for UC vs. hc). CD patients with high ASCA titers had significantly lower H-ficolin concentrations compared to ASCA-low/negative CD patients (p=0.009). However, MASP-2 activity was not different in ASCA-negative and ASCA-positive CD patients upon both, ficolin- or MBL-mediated MASP-2 activation. Finally, anti-MBL autoantibodies were not over-represented in MBL-proficient ASCA-positive CD patients. CONCLUSIONS: Our results suggest that low expression of H-ficolin may promote elevated ASCA titers in the ASCA-positive subgroup of CD patients. However, unlike MBL deficiency, we found no evidence for low expression of serum ficolins or reduced MASP-2 activity that may predispose to ASCA development.

Trapeziectomy and tendon suspension with or without a mitek anchor fixation in the thumb basal joint osteoarthritis.

Partial trapeziectomy with suspension ligamentoplasty is a commonly performed treatment of thumb osteoarthritis. Nevertheless, the post-operative recovery remains long and critical reason for which different modifications of the surgical technique have been proposed. To compare two suspension ligamentoplasty techniques, one with a mitek anchor and another without, a retrospective study of 55 consecutive operated patients was performed. A detailed clinical analysis of pain, function and a radiologic assessment of the trapeziometacarpal space were performed. Mitek anchor fixation was associated with a shorter convalescence period. However, in spite of an improved radiological maintenance of the scaphometacarpal space, mitek anchor fixation was associated with an impaired postoperative function and residual pain when compared with the conventional suspension ligamentoplasty procedure. Patient's satisfaction was comparable in both groups. In our series stabilization of the suspension ligamentoplasty procedure by the insertion of a mitek anchor did not bring the hoped benefits to the patients with a trapeziometacarpal arthritis.