Mechanical Characterization at the Microscale of Mineralized Bone Callus after Bone Lengthening

Distraction osteogenesis (DO) involves several processes to form an organized distracted callus. While bone regeneration during DO has been widely described, no study has yet focused on the evolution profile of mechanical properties of mineralized tissues in the distracted callus. The aim of this study was therefore to measure the elastic modulus and hardness of calcified cartilage and trabecular and cortical bone within the distracted callus during the consolidation phase. We used a microindentation assay to measure the mechanical properties of periosteal and endosteal calluses; each was subdivided into two regions. Histological sections were used to localize the tissues. The results revealed that the mechanical properties of calcified cartilage did not evolve over time. However, trabecular bone showed temporal variation. For elastic modulus, in three out of four regions, a similar evolution profile was observed with an increase and decrease over time. Concerning hardness, this evolves differently depending on the location in the distracted callus. We also observed spatial changes in between regions. A first duality was apparent between regions close to the native cortices and the central area, while latter differences were seen between periosteal and endosteal calluses. Data showed a heterogeneity of mechanical properties in the distracted callus with a specific mineralization profile.     

Multiscale Femoral Neck Imaging and Multimodal Trabeculae Quality Characterization in an Osteoporotic Bone Sample

Although multiple structural, mechanical, and molecular factors are definitely involved in osteoporosis, the assessment of subregional bone mineral density remains the most commonly used diagnostic index. In this study, we characterized bone quality in the femoral neck of one osteoporotic patients as compared to an age-matched control subject, and so used a multiscale and multimodal approach including X-ray computed microtomography at different spatial resolutions (pixel size: 51.0, 4.95 and 0.9 µm), microindentation and Fourier transform infrared spectroscopy. Our results showed abnormalities in the osteocytes lacunae volume (358.08 ± 165.00 for the osteoporotic sample vs. 287.10 ± 160.00 for the control), whereas a statistical difference was found neither for shape nor for density. The osteoporotic femoral head and great trochanter reported reduced elastic modulus (Es) and hardness (H) compared to the control reference (−48% (p < 0.0001) and −34% (p < 0.0001), respectively for Es and H in the femoral head and −29% (p < 0.01) and −22% (p < 0.05), respectively for Es and H in the great trochanter), whereas the corresponding values in the femoral neck were in the same range. The spectral analysis could distinguish neither subregional differences in the osteoporotic sample nor between the osteoporotic and healthy samples. Although, infrared spectroscopic measurements were comparable among subregions, and so regardless of the bone osteoporotic status, the trabecular mechanical properties were comparable only in the femoral neck. These results illustrate that bone remodeling in osteoporosis is a non-uniform process with different rates in different bone anatomical regions, hence showing the interest of a clear analysis of the bone microarchitecture in the case of patients’ osteoporotic evaluation.     

Evaluation of Rapid Lateral-Flow Tests Directed against the SARS-CoV-2 Nucleoprotein Using Viral Suspensions Belonging to Different Lineages of SARS-CoV-2

Within the successive waves that occurred during the SARS-CoV-2 pandemic, recommendations arose to test symptomatic and contact subjects by using rapid antigen devices directed against the viral nucleocapsid protein with the aim to isolate contagious patients without delay. The objective of this study was to evaluate the ability of four rapid lateral-flow tests (RLFT) that were commercially available on the French market in 2022 to recognize various strains of SARS-CoV-2. Series of five-fold dilutions of seven viral suspensions belonging to different lineages of SARS-CoV-2 (19A, 20A, Alpha, Beta, Gamma, Delta and Omicron) were used to evaluate the analytical sensitivity of four commercially available RLFTs (manufacturers: Abbott, AAZ, Becton-Dickinson and Biospeedia). Cell culture and quantitative RT-PCR were used as references. Excellent correlations were observed for each lineage strain between the viral titer obtained via cell culture and the number of RNA copies measured by quantitative RT-PCR. Although the four tests were able to recognize all the tested variants, significant differences in terms of sensitivity were observed between the four RLFTs. Despite the limitation represented by the small number of devices and clinical isolates that were tested, this study contributed by rapidly comparing the sensitivity of SARS-CoV-2 RLFTs in the Omicron era.     

Discourses on the Toxic Effects of Internal Chemical Contamination in Catalonia,Spain

Human exposure to and contamination by environmental toxic compounds generates discourses and practices that merit greater attention. In this article, we assess internal chemical contamination and the risk of toxic effects as an experience related to the production of meaning in everyday life. Drawing on the analysis of semantic networks of narratives from semi-structured interviews conducted with 43 informants in Catalonia, Spain, we consider participants’ perceptions of the health risks of toxic compounds, including social discourses on exposure, toxicity, and internal chemical contamination, and on responsibilities, consequences, and proposed strategies for controlling toxic compounds. Informants’ narratives on the relationships between nature and nurture suggest that they no longer perceive rigid boundaries separating the human body from the external environment and its chemical pollutants.     

Bcl-2 protein expression is the strongest independent prognostic factor of survival in primary cutaneous large B-cell lymphomas

Bcl-2 protein expression has been associated with poor prognosis in patients with noncutaneous diffuse large B-cell lymphomas. In primary cutaneous large B-cell lymphomas, the location on the leg, the round-cell morphology defined as the predominance of centroblasts and immunoblasts over large centrocytes, and multiple skin lesions were identified as adverse prognostic factors. The prognostic value of bcl-2 protein expression has not been studied in large series of patients. We evaluated 80 primary cutaneous large B-cell lymphomas collected by the French Study Group on Cutaneous Lymphomas. The prognostic value of age, sex, number of lesions, cutaneous extent, location, serum lactate dehydrogenase (LDH) level, B symptoms, morphology, and bcl-2 protein expression was studied. The overall 5-year specific survival rate was 65%. In univariate analysis, advanced age, multiple skin lesions (n = 48), location on the leg (n = 25), round-cell morphology (n = 32), and bcl-2 expression (n = 39) were significantly related to death from lymphoma. In multivariate analysis, bcl-2 expression (P =.0003), multiple skin lesions (P =.004), and age remained independent prognostic factors. The 5-year specific survival rates in bcl-2-positive and bcl-2-negative patients were 41% and 89%, respectively (P <.0001). A new prognostic classification of primary cutaneous B-cell lymphoma should be based primarily on bcl-2 protein expression rather than the location of skin lesions.     

The genome sequence of the probiotic intestinal bacterium Lactobacillus johnsonii NCC 533

Lactobacillus johnsonii NCC 533 is a member of the acidophilus group of intestinal lactobacilli that has been extensively studied for their "probiotic" activities that include, pathogen inhibition, epithelial cell attachment, and immunomodulation. To gain insight into its physiology and identify genes potentially involved in interactions with the host, we sequenced and analyzed the 1.99-Mb genome of L. johnsonii NCC 533. Strikingly, the organism completely lacked genes encoding biosynthetic pathways for amino acids, purine nucleotides, and most cofactors. In apparent compensation, a remarkable number of uncommon and often duplicated amino acid permeases, peptidases, and phosphotransferase-type transporters were discovered, suggesting a strong dependency of NCC 533 on the host or other intestinal microbes to provide simple monomeric nutrients. Genome analysis also predicted an abundance (>12) of large and unusual cell-surface proteins, including fimbrial subunits, which may be involved in adhesion to glycoproteins or other components of mucin, a characteristic expected to affect persistence in the gastrointestinal tract (GIT). Three bile salt hydrolases and two bile acid transporters, proteins apparently critical for GIT survival, were also detected. In silico genome comparisons with the >95% complete genome sequence of the closely related Lactobacillus gasseri revealed extensive synteny punctuated by clear-cut insertions or deletions of single genes or operons. Many of these regions of difference appear to encode metabolic or structural components that could affect the organisms competitiveness or interactions with the GIT ecosystem.     

Pathogenicity of IgA and/or IgM antibodies to heparin–PF4 complexes in patients with heparin-induced thrombocytopenia

Antibodies to heparin–PF4 (H-PF4) complexes have been tested and isotyped in 38 patients who developed severe heparin-induced thrombocytopenia (type II HIT). All the patients had a platelet count < 120 × 10⁹/l or a reduction of >30% of the initial value, occurring at least 5 d after the onset of heparin. Thrombocytopenia, which rapidly reversed following the withdrawal of heparin, was associated with thrombosis in nine patients. Although IgG isotypes were found in most cases ( n  = 26), the presence of only IgM and/or IgA was observed in 12 patients, including three cases showing a thrombotic complication. Our results indicate that type II HIT may be induced by IgA and/or IgM anti-H-PF4 antibodies even in the absence of IgG isotypes. This finding demonstrates that platelet Fc receptors (FcγRII) are not necessarily involved in the pathogenicity of heparin-dependent antibodies and emphasizes the major role of platelet PF4 receptors. The increased expression of the latter following a slight activation by thrombin, and the subsequent binding of IgM and IgA antibodies to H-PF4 on the platelet surface, may directly trigger platelet activation, aggregation and thrombosis. Alternatively, thrombocytopenia could be indirectly induced through the mediation of neutrophils, monocytes and lymphocytes which expose receptors for IgA (FcαR) or IgM (FcμR). IgM–platelet complexes may also bind and activate complement, leading to platelet activation or destruction. Moreover, the reactivity of the antibodies with glycosaminoglycans–PF4 complexes present on the endothelial surface could also induce endothelial lesions and promote procoagulant activity and predisposition to thrombosis.     

Pharmacology of the urotensin-II receptor antagonist palosuran (ACT-058362; 1-[2-(4-benzyl-4-hydroxy-piperidin-1-yl)-ethyl]-3-(2-methyl-quinolin-4-yl)-urea sulfate salt): first demonstration of a pathophysiological role of the urotensin System

Urotensin-II (U-II) is a cyclic peptide now described as the most potent vasoconstrictor known. U-II binds to a specific G protein-coupled receptor, formerly the orphan receptor GPR14, now renamed urotensin receptor (UT receptor), and present in mammalian species. Palosuran (ACT-058362; 1-[2-(4-benzyl-4-hydroxy-piperidin-1-yl)-ethyl]-3-(2-methyl-quinolin-4-yl)-urea sulfate salt) is a new potent and specific antagonist of the human UT receptor. ACT-058362 antagonizes the specific binding of (125)I-labeled U-II on natural and recombinant cells carrying the human UT receptor with a high affinity in the low nanomolar range and a competitive mode of antagonism, revealed only with prolonged incubation times. ACT-058362 also inhibits U-II-induced calcium mobilization and mitogen-activated protein kinase phosphorylation. The binding inhibitory potency of ACT-058362 is more than 100-fold less on the rat than on the human UT receptor, which is reflected in a pD'(2) value of 5.2 for inhibiting contraction of isolated rat aortic rings induced by U-II. In functional assays of short incubation times, ACT-058362 behaves as an apparent noncompetitive inhibitor. In vivo, intravenous ACT-058362 prevents the no-reflow phenomenon, which follows renal artery clamping in rats, without decreasing blood pressure and prevents the subsequent development of acute renal failure and the histological consequences of ischemia. In conclusion, the in vivo efficacy of the specific UT receptor antagonist ACT-058362 reveals a role of endogenous U-II in renal ischemia. As a selective renal vasodilator, ACT-058362 may be effective in other renal diseases.     

Inv(X)(p21.1;q22.1) in a man with mental retardation,short stature,general muscle wasting,and facial dysmorphism: clinical study and mutation analysis of the NXF5 gene

We describe a 59-year-old male (patient A059) with moderate to severe mental retardation (MR) and a pericentric inversion of the X-chromosome: inv(X)(p21.1;q22.1). He had short stature, pectus excavatum, general muscle wasting, and facial dysmorphism. Until now, no other patients with similar clinical features have been described in the literature. Molecular analysis of both breakpoints led to the identification of a novel "Nuclear RNA export factor" (NXF) gene cluster on Xq22.1. Within this cluster, the NXF5 gene was interrupted with subsequent loss of gene expression. Hence, mutation analysis of the NXF5 and its neighboring homologue, the NXF2 gene was performed in 45 men with various forms of syndromic X-linked MR (XLMR) and in 70 patients with nonspecific XLMR. In the NXF5 gene four nucleotide changes: one intronic, two silent, and one missense (K23E), were identified. In the NXF2 gene two changes (one intronic and one silent) were found. Although none of these changes were causative mutations, we propose that NXF5 is a good candidate gene for this syndromic form of XLMR, given the suspected role of NXF proteins is within mRNA export/transport in neurons. Therefore, mutation screening of the NXF gene family in phenotypically identical patients is recommended.     

Interaction of Avibactam with Class B Metallo-β-Lactamases

β-Lactamases are the most important mechanisms of resistance to the β-lactam antibacterials. There are two mechanistic classes of β-lactamases: the serine β-lactamases (SBLs) and the zinc-dependent metallo-β-lactamases (MBLs). Avibactam, the first clinically useful non-β-lactam β-lactamase inhibitor, is a broad-spectrum SBL inhibitor, which is used in combination with a cephalosporin antibiotic (ceftazidime). There are multiple reports on the interaction of avibactam with SBLs but few such studies with MBLs. We report biochemical and biophysical studies on the binding and reactivity of avibactam with representatives from all 3 MBL subfamilies (B1, B2, and B3). Avibactam has only limited or no activity versus MBL-mediated resistance in pathogens. Avibactam does not inhibit MBLs and binds only weakly to most of the MBLs tested; in some cases, avibactam undergoes slow hydrolysis of one of its urea N-CO bonds followed by loss of CO₂, in a process different from that observed with the SBLs studied. The results suggest that while the evolution of MBLs that more efficiently catalyze avibactam hydrolysis should be anticipated, pursuing the development of dual-action SBL and MBL inhibitors based on the diazabicyclooctane core of avibactam may be productive.