Changes in the gut microbiota of pseudoxanthoma elasticum patients.

OBJECTIVE: Pseudoxanthoma elasticum (PXE) is a rare autosomal disorder with a variable phenotype that may be modulated by environmental factors. Plasma vitamin K (VK) levels may be involved in the ectopic calcification process observed in PXE. Since VK2 is predominantly produced by the gut microbiota, we hypothesized that changes in the gut microbiota of PXE patients might exacerbate the calcification process and disease symptoms. METHODS: Twenty PXE patients were included in the study and 60 gut microbiota profiles from the Biofortis laboratory database were used as controls. RESULTS: The Rhodospirillaceae family was more abundant in the PXE group while the Sphingomonadaceae family was more abundant in the control group. In a PXE severity subgroup analysis, microbiota dispersion was lower in "severe" than in "non-severe" patients, which was confirmed by permutation multivariate analysis of variance at the phylum, family and genus ranks. However, no significant association was found in a model incorporating relative abundance of bacterial families, severity score, and different blood and fecal VK species. CONCLUSION: These results suggest slight compositional changes in the gut microbiota of PXE patients. Further studies are needed to substantiate their impact on VK metabolism and the calcification process.

Penetration of daptomycin into bone and synovial fluid in joint replacement.

Daptomycin exhibits clinical activity in the treatment of infections with Gram-positive organisms, including infections due to methicillin-resistant Staphylococcus aureus. However, little is known about its penetration into bone and synovial fluid. The aim of our study was to assess the penetration of daptomycin into bone and synovial fluid after a single intravenous administration. This study was conducted in 16 patients who underwent knee or hip replacement and received a single intravenous dose of 8 mg of daptomycin per kg of body weight prior to surgery. Plasma daptomycin concentrations were measured 1 h after the end of daptomycin infusion and when bone fragments were removed. Daptomycin concentrations were also measured on bone fragments and synovial fluid collected at the same time during surgery. All samples were analyzed with a diode array-high-performance liquid chromatography (HPLC) method. After a single-dose intravenous infusion, bone daptomycin concentrations were above the MIC of daptomycin for Staphylococcus aureus in all subjects, and the median bone penetration percentage was 9.0% (interquartile range [IQR], 4.4 to 11.4). These results support the use of daptomycin in the treatment of Staphylococcus aureus bone and joint infections.

Microclimate next to the skin: influence on percutaneous absorption of caffeine (ex-vivo study).

BACKGROUND/PURPOSE: Contact between skin surface and external environment induces a microclimate at the skin surface. That microclimate affects skin interaction with xenobiotics substances. We have developed a new device to explore the influence of environmental parameters, on percutaneous absorption. The aim of this study was to study the influence of external humidity and temperature on percutaneous absorption of caffeine. METHODS: Six exposure conditions were tested: four by combining two temperatures (27°C and 42°C) with two relative humidities (28% and 70%), performed by our device and two others by using Franz diffusion cell (unoccluded conditions, with skin surface in contact with ambient laboratory environment (27°C/33%) and in occluded conditions with skin surface covering by impermeable membrane). RESULTS: Kinetic curve profile of percutaneous absorption of caffeine revealed different shapes characteristics depending on environmental exposure conditions. These profiles were related to evaporative process, of deposited preparation on skin surface combined with water uptake resulting from water flux through skin. CONCLUSION: Our results highlight a preponderant role of microclimate above the skin on percutaneous absorption of caffeine. The device used in this study will be a useful tool to investigate ex vivo, the influence of microclimate on percutaneous absorption.

Human Papillomavirus (HPV) vaccination coverage among French adolescents: A claims data study.

BACKGROUND: The French cancer control strategy 2021-2030 aims to achieve 80 % human papillomavirus (HPV) vaccination coverage. Since 2021, HPV vaccination is also recommended for boys aged 11-14 years, with a catch-up vaccination recommended for unvaccinated adolescents aged ≤19 years. The PAPILLON study used claims data to monitor the evolution of HPV Vaccination Coverage Rate (VCR) in the French population. METHODS: The annual HPV VCR was described from 2017 to 2022. Partial vaccination was defined as the dispensing of at least one dose of HPV vaccination. Full scheme vaccination was defined according to the current French recommendations as two or three doses of HPV vaccine over an 18-month period. Annual HPV vaccine initiation rates were estimated on 11-14 and 15-19-year-olds adolescents. Cumulative VCR were estimated on adolescents aged between 11 and 19 years at the time of first vaccination. RESULTS: Overall, 1,773,900 females and 592,167 males initiated HPV vaccination between 2017 and 2022. Initiations occurred between 11 and 14 years for 67.3 % of females and 62.4 % of males with a median time between the first two doses of 195 days and 190 days, respectively. In girls, the cumulative vaccination rate for the partial scheme vaccination at 15 y.o. increased from 28.1 % in 2017 to 50.9 % in 2022. Similarly, the cumulative vaccination rate for the full scheme vaccination at 16 y.o. increased from 15.5 % in 2017 to 33.8 % in 2022. In 2022, the initiation rates for males were 12.6 % at age 14 and 1.9 % at age 19. CONCLUSIONS: HPV vaccination coverage increased between 2017 and 2022 among girls targeted by the recommendation but remains insufficient. The results of this study show a tentative but promising start to vaccination in boys. This study will monitor the effects of actions taken to improve vaccination, including the extension of vaccination competencies to community pharmacists since end of 2022.

Mediating effect of sleep in the association between social media use and mental health among French adolescents during the COVID-19 sanitary crisis.

OBJECTIVE/BACKGROUND: Social media use could have deleterious effects on mental health through short sleep duration and poor sleep quality among adolescents. This study aimed to investigate the mediating role of both sleep duration and sleep quality in the association between social media use and mental health among adolescents. PATIENTS/METHODS: We used cross-sectional data collected from adolescents in the EXIST pilot project conducted during COVID-19 pandemic. Adolescents self-reported wellbeing (WEMWBS), anxiety and depression (HADS) as mental health outcomes. We used ad-hoc questionnaires to assess social media use during weekdays and weekend days, and sleep duration and quality. Mediation analyses were carried out following Baron and Kenny's method, using adjusted linear regression models. RESULTS: A total of 340 adolescents (13.5 ± 0.6 years, 45.3 % girls) were included. Greater social media use, poorer sleep quality, and shorter sleep duration were associated with poorer mental health. Greater social media use was associated with poorer sleep quality only during the weekend days. The total effect of social media use during weekend days on anxiety (ß = 2.54; 95%CI [-1.59; 6.68]) was significantly conveyed through sleep quality (ß = 1.22; 95%CI [0.17; 2.62]; mediated proportion = 48.0 %) and duration (mediated proportion = 46.8 %). Mediated proportions ranged from 12.5 % to 20.6 % for wellbeing and depression. Mediating effects were not evident during weekdays. CONCLUSIONS: Sleep duration and quality mediated the association between social media use and mental health among adolescents during weekend days but not weekdays. Our findings highlight the importance of promoting healthy social media habits, especially during periods of increased reliance on digital platforms, such as COVID-19 pandemic.

FLICE-inhibitory protein is a key regulator of germinal center B cell apoptosis.

Affinity maturation of the B cell response to antigen (Ag) takes place in the germinal centers (GCs) of secondary follicles. Two sequential molecular mechanisms underpin this process. First, the B cell repertoire is diversified through hypermutation of the immunoglobulin (Ig) variable region genes. Second, mutant B cell clones with improved affinity for Ag are positively selected by Ag and CD40 ligand (L). This selection step is contingent upon "priming" of GC B cells for apoptosis. The molecular means by which B cell apoptosis is initiated and controlled in the GC remains unclear. Here, we show that GC B cell apoptosis is preceded by the rapid activation of caspase-8 at the level of CD95 death-inducing signaling complex (DISC). We found that GC B cells ex vivo display a preformed inactive DISC containing Fas-associated death domain-containing protein (FADD), procaspase-8, and the long isoform of cellular FADD-like IL-1beta-converting enzyme-inhibitory protein (c-FLIP(L)) but not the CD95L. In culture, c-FLIP(L) is rapidly lost from the CD95 DISC unless GC B cells are exposed to the survival signal provided by CD40L. Our results suggest that (a) the death receptor signaling pathway is involved in the affinity maturation of antibodies, and (b) c-FLIP(L) plays an active role in positive selection of B cells in the GC.

[Use of sorafenib in patients with hepatocellular or renal carcinoma]. / Bon usage du sorafénib chez les patients pris en charge pour un carcinome hépatocellulaire ou un cancer du rein.

Therapeutic approaches of cancers have been recently improved by the development of targeted therapies. Amongst these new drugs, some anti-angiogenic molecules have been approved by either the EMEA or the Food and Drug Administration. Sorafenib, one of these inhibitors of angiogenesis, has been established as the standard of care for advanced hepatocellular and renal carcinoma. This paper reviews the safety profile of sorafenib and presents guidelines for the prevention and the treatment of the main side effects associated with this molecule.

Cytotoxic effect of serum on fibroblasts in one case of normolipidemic plane xanthoma and myeloma IgG lambda.

Serum was examined for a cytotoxic effect on cultured human fibroblasts, using 8 normal controls and 4 patients. Three of the patients had secondary lipidoses associated with monoclonal gammapathies of IgA kappa, IgG kappa and IgG lambda types. The fourth had systemic lupus erythematosus (SLE) with hyperlipidemia. Only serum containing the monoclonal IgG lambda was found to be cytotoxic. This circulating IgG lambda was strongly bound to HDL and behaved like an antilipoprotein antibody. The circulating immune complexes may be the serum factor responsible for the cytotoxicity and the cutaneous plane xanthomas, thus giving another example of 'antibody-dependent' cellular cytotoxicity previously described for endothelial cells in other diseases.

Inhibition of lipoprotein lipase activity by a monoclonal immunoglobulin in autoimmune hyperlipidemia.

Autoimmune hyperlipidemia (AIH) may be induced a variety of antibodies which inhibit different stages of the lipolytic process by which the lipid load is removed from the circulating lipoproteins. In a patient having a monoclonal gammopathy and a nephrotic syndrome with a glomerulonephritis and a marked hypertriglyceridemia, it was found previously that the monoclonal IgG gamma Lac. reacted with human VLDL as well as with human serum albumin. Here it is demonstrated that the purified IgG gamma inhibits the lipolysis of triglyceride substrates by reacting with a substance (Lac. S) necessary for lipoprotein lipase activity. The interaction of IgG lambda Lac. with serum or HDL-activated triglyceride substrates inhibits the lipolytic activity of human and rat plasma post heparin and also adipose tissue lipases. It slightly inhibits the activity of swine pancreatic lipases. The Lac S. which reacts with IgG Lac. is associated to whole and delipidated VLDL and HDL and not to LDL or purified APo-A. It may be an Apo-C or a non-peptidic co-factor of the lipases which remains bound to the apoprotein core after delipidation. Its lack of species specificity and its presence as traces in HSA preparations favors the latter hypothesis. The Lac. substances is different from the Pg and As substances which were found to react with IgA anti-Pg and IgG anti-As antibodies in previously reported antilipoprotein AIH.

Antiphospholipid antibody production during Mediterranean spotted fever.

Antiphospholipid antibodies (aPLA) were discovered during the course of Mediterranean spotted fever (MSF) caused by Rickettsia conorii and characterized by endothelial cell (EC) damage resulting from this organism's tropism for EC. In two MSF patients, two types of aPLA were identified: antiphosphatidylethanolamine antibodies detected by immunological methods and lupus anticoagulant detected by clotting assays. The persistence of both aPLA for several months after the acute phase and clinical recovery might correspond to a durable immunological response to membrane damage of EC caused by R. conorii. Their possible role in the pathophysiology of microthrombi formation observed during MSF remains to be elucidated in a study on a larger number of patients.

Vascular origin determines angiotensin I-converting enzyme expression in endothelial cells.

Previous observations on the heterogeneous distribution of von Willebrand factor in the vascular endothelium led us to examine the expression of angiotensin I-converting enzyme (ACE) in function of the vascular origin of endothelial cells (EC). EC from pig thoracic aorta, pulmonary artery, inferior vena cava and brain capillaries were cultured and assayed for ACE by enzymatic radiochemical determination and by western-blot and immunofluorescence using an antiACE polyclonal antibody. EC from the various vascular levels secreted ACE in the culture medium; western-blot analysis showed its presence at cellular level and immunofluorescence confirmed its location on the plasma membrane. But quantification revealed that EC from pulmonary artery contain more ACE than EC from the other vessels, especially from brain capillaries; immunofluorescence correlated well with the functional data. In contrast, secretion of ACE by brain capillaries EC was faster than that of arteries and of vena cava, the latter being the less effective. This differential ACE expression along the vascular tree could have a pharmacological implication since ACE inhibitors, used in the treatment of arterial hypertension, may act more at the vascular level than on the plasma renin-angiotensin system. On the other hand, endothelial distribution of ACE was different from that of von Willebrand factor; in particular we showed that EC cultured from vessels of pigs homozygous for the von Willebrand disease, in which von Willebrand factor synthesis was completely abolished, normally express ACE.

Advantage of using both anionic and zwitterionic phospholipid antigens for the detection of antiphospholipid antibodies.

To investigate the benefit of assaying for antiphospholipid antibodies (aPA) with different antigenic specificities, sera from 141 patients suspected of having aPA were tested by ELISA for IgG and IgM antibodies directed against the following phospholipids (PL) coated individually or together: cardiolipin, phosphatidylinositol, phosphatidylserine and phosphatidylethanolamine. Nonspecific background optical density (OD) was systematically subtracted from the test OD value. Positive reactions were defined as having an OD greater than the 97th percentile OD distribution obtained with sera from 100 healthy individuals. Although the majority of the 79 detected aPA (89% IgG and 77% IgM) were polyspecific, 11 reacted with a single PL and, moreover, belonged to only one isotype. Seven of these 11 patients presented recurrent fetal losses or thrombotic events. These results suggest that routine use of a mixture of both anionic and zwitterionic PL antigens to coat ELISA plates would better detect aPA involved in suggestive pathologies and enhance the ability to identify patients with these mono- or polyspecific antibodies directed or not against cardiolipin, the current standard.

Guidelines for estimating the real cost of an objective structured clinical examination.

A major impediment to the use of the objective structured clinical examination (OSCE) is that it is a labor-intensive and costly form of assessment. The cost of an OSCE is highly dependent on the particular model used, the extent to which hidden costs are reported, and the purpose of the examination. The authors detail hypothetical costs of running a four-hour OSCE for 120 medical students at one medical school. Costs are reported for four phases of this process: development, production, administration, and post-examination reporting and analysis. Costs are reported at two ends of the spectrum: the high end, where it is assumed that little is paid for by the institution and that faculty receive honoraria for work put into the examination; and the low end, where it is assumed that the sponsoring institution defrays basic costs and that faculty do not receive honoraria for their participation. The total costs reported for a first-time examination were $104,400 and $59,460 (Canadian dollars) at the high and low ends, respectively. These translate to per-student costs of $870 and $496. The cost of running an OSCE is high. However, the OSCE is uniquely capable of assessing many fundamental clinical skills that are presently not being assessed in a rigorous way in most medical schools.

Amino acid metabolism during total parenteral nutrition in healthy volunteers: evaluation of a new amino acid solution.

The aim of this study was to determine the metabolism and the tolerance of a new amino acid (AA) solution administered under conditions mimicking cyclical parenteral nutrition (PN) in humans. Eight healthy volunteers received peripheral PN for 10 h providing 10.5 mg N x kg(-1) x h(-1) and 2.0 kcal x kg(-1) x h(-1) (glucose-to-lipids ratio: 70/30%). For adaptation, a non-protein energy intake was increased progressively for 90 min; thereafter, AA infusion was started and maintained at a constant rate for 10 h. Plasma and urine concentrations of all the AAs were measured before, during and after the PN. For each given AA, the relation between plasma variations at the steady-state and infusion rate, plasma clearance (Cl), renal clearance (Clr), re-absorption rate (Reab) and, retention rate (Reten) were determined. The nitrogen balance (DeltaN) was calculated during the PN period. The results are presented as means+/-sem. All plasma AA concentrations decreased during the starting period of non-protein energy intake. The plasma AA concentrations reached a steady-state within 3 h upon AA infusion, except for glycine and lysine (6 h). At the steady state, the plasma concentrations of the infused AAs were closely correlated to their infusion rate (y= -18.3+1.5x, r(2)=0.92). The plasma glutamine concentration was maintained during the PN, which indicates that the solution might stimulate the de novo synthesis of this AA. When the PN was stopped, plasma levels of the AAs decreased, most of them returning to their basal levels, or significantly below for lysine (P<0.05), alanine (P<0.05), proline (P<0.01) and glutamine (P<0.05). No volunteer showed any adverse effect during the infusion period. DeltaN was: 0.8+/-0.5 gN/10 h. Metabolic characteristics for essential AAs were: Cl<0.5 l min(-1), Clr <1.5 ml x min(-1) Reab >or= 99%, Reten >or=99% and for non-essential AAs: Cl <0.6 l x min(-1) except aspartate (2.8+/-0.3 l x min(-1)), Clr < 3 ml x min(-1) except glycine (6.8+/-0.7), aspartate (8.2+/-3.5) and histidine (8.8+/-1.3); Reab >or= 98% except glycine (95+/-1), aspartate (94+/-2) and histidine (94+/-1), Reten >or=97% except histidine (94+/-1), glycine (95+/-3). These results indicate that in healthy subjects, the amounts of AAs provided by the new solution were well balanced for an intravenous administration, and so were well utilized without excessive urinary excretion. The present study provides useful metabolic parameters for a further evaluation in disease.

Transendothelial migration of two metastatic breast carcinoma cells depend on the SDF-lalpha-CXCR4 complexes.

The role of the SDF-1alpha chemokine-CXCR4 receptor system on tumor cell transendothelial migration was studied by culturing metastatic breast tumor cell lines, MDA-MB-231 and MDA-MB-435, either alone or on a HUVEC monolayer pre-established on a "Transwell" filter. After a 24-hour culture in the presence or absence of SDF-1alpha, tumor cell transmigration rates were compared. We showed that: CXCR4 is present on both cell lines; MDA-MB-231 but not MDA-MB-435 cell migration is stimulated by increasing concentrations of SDF-1alpha; neutralizing anti-CXCR4 antibody inhibits the SDF-1alpha chemoattractant effect; CXCR4 expression, measured by cytofluorometry, was enhanced after treatment with SDF-1alpha on MDA-MB-231 cells but remained unchanged on MDA-MB-435 cells; Scatchard analysis evidences 8.10(5) and 2.10(5) high affinity sites (KD range: 20 to 30 nM) on, respectively, MDA-MB-231 and MDA-MB-435 cells. These significant differences could explain the distinctive transendothelial migration responses of these two cell lines in the presence of SDF-1alpha.

Thrombomodulin, a functional surface protein on human keratinocytes, is regulated by retinoic acid.

Thrombomodulin, a major anticoagulant proteoglycan of the endothelial cell membrane, is a thrombin receptor that acts as a cofactor for protein C activation. It has previously been shown that thrombomodulin, present in human epidermis and in lysates of cultured keratinocytes, is implicated in cellular differentiation during mouse fetal development. The role of retinoic acid in keratinocyte differentiation prompted us to study retinoic acid regulation of thrombomodulin expression in primary cultures of keratinocytes isolated from adult human skin, grown at low (undifferentiated keratinocytes) and normal calcium levels (differentiated keratinocytes). Thrombomodulin antigen levels and total and surface activities were measured in cultures without and with retinoic acid. Thrombomodulin mRNA visualized by in situ hybridization was quantified by computer-based image analysis. Functional thrombomodulin was expressed on the surface and in the cytoplasm of cultured human keratinocytes regardless of the calcium concentration. In contrast, retinoic acid induced significant increases in the total antigen level and in surface and intracellular thrombomodulin activities only in keratinocytes grown in a low-calcium medium. In these undifferentiated keratinocytes, quantification of mRNA transcripts showed a threefold increase after retinoic acid stimulation. Thus, functional thrombomodulin is a human keratinocyte surface protein whose expression is controlled through the keratinocyte differentiation program and is modulated in vitro by retinoic acid.

Shear stress modulates tumour cell adhesion to the endothelium.

The adhesion of breast adenocarcinoma cells (MDA-MB-231) to human umbilical vein endothelial cells (HUVEC) was studied in whole blood and under varying flow conditions. This study was done on HUVEC either kept under static conditions or pre-conditioned in flow for 2 hours at a shear stress of 5 or 13 dyn/cm(2). Coverslips coated by HUVEC were placed in a parallel plate perfusion chamber and perfused at a shear rate of 300 or 1500 sec(-1) with heparin-anticoagulated blood containing 111In labelled MDA-MB-231 cells. We report here the optimal conditions for studying the adhesion of MDA-MB-231 to endothelial cells under shear constraints corresponding to those observed into small and medium sized arteries.

Similarities and/or dissimilarities of CYP2D6 polymorphism in three Tunisian ethnic groups: Arabs, Berbers, Numides.

Using the validated probe drug debrisoquine and the 8 h urinary metabolic ratio debrisoquine/4 hydroxy-debrisoquine, we have determined the phenotype of the debrisoquine CYP2D6 dependent polymorphic metabolism in 464 Arabs, 227 Berbers and 215 Numides to elicit similarities or dissimilarities of poor metabolizer (PM) prevalence. We found 2.36 per cent of PM in Arabs, 3.08 per cent in Berbers and 2.33 per cent in Numides. These figures are similar to those observed in Middle East populations, and cannot be considered as different from those observed in Caucasians.

[Therapeutic drug monitoring of mycophenolate mofetil, sirolimus and cyclosporine at C2]. / Suivi thérapeutique pharmacologique de l'acide mycophénolique, du sirolimus et de la cilosporine au moyen du C2.

The evolutions in treatments and clinical practices in organ transplantations led to modifications in the therapeutic drug monitoring (TDM) of immunosuppressive drugs. A focus is made regarding the C2 sampling of cyclosporin, as well as the TDM of mycophenolate mofetil and sirolimus. A review of literature about the evolution of drug monitoring, technical methods and sampling strategies is described. Arguments in favour of TDM are thus a decrease in the frequency of both graft rejection and adverse drug reactions, however, new strategies or new targets are needed in new associations or indications.