Surgical treatment of stapes fixation

The aim of surgical treatment of a fixed stapes is to restore an as effective as possible impedance transfer of the ossicular chain and acoustic impedance of the annular ligament of the footplate, when it has lost elasticity, and this in order to achieve the best possible physiological vibration of the inner ear fluids.     

Type 2N von Willebrand disease

Type 2N von Willebrand disease (VWD) refers to patients with a factor VIII (FVIII) deficiency caused by a markedly decreased affinity of von Willebrand factor (VWF) for FVIII. It is inherited as an autosomal recessive trait but is clinically similar to mild hemophilia. The differential biologic diagnosis, which is of major importance for providing relevant genetic counseling and optimal treatment, is based on the measurement of plasma VWF capacity to bind FVIII. Molecular biology techniques have allowed the identification of 20 missense mutations in the VWF gene that cause type 2N VWD. All of them induce changes in amino acid residues located in the N-terminal part of mature VWF, which contains the FVIII binding site. Their identification may provide a genetic diagnosis. Theoretically, patients with type 2N VWD should be treated with products containing VWF that is able to stabilize their endogenous normal FVIII.     

Negative preclinical results with stealth nanospheres-encapsulated Doxorubicin in an orthotopic murine brain tumor model.

Previous results have shown that PEG-coated poly(hexadecylcyanoacrylate) (PEG-PHDCA) nanospheres displayed a significant accumulation within an orthotopic 9L gliosarcoma model, after i.v. administration to rats. Hence, the aim of the present study was to evaluate in the same model the pre-clinical efficacy of this carrier when loaded with Doxorubicin, an anticancer drug which poorly distributes in the CNS. Free and nanospheres-encapsulated Doxorubicin were administered with a multiple dose treatment. Their maximum tolerated dose (MTD) and increase in life span were respectively assessed in healthy and intracranially 9L-bearing rats. A comparative biodistribution study of Doxorubicin-loaded and unloaded PEG-PHDCA nanospheres was also performed in the tumor-bearing group. The results showed that the cumulative MTD of nanoparticulate doxorubicin was 1.5 times higher than this of free Doxorubicin. Nevertheless, encapsulated Doxorubicin was unable to elicit a better therapeutic response in the 9L gliosarcoma. Biodistribution study revealed that the Doxorubicin-loaded nanospheres accumulated to a 2.5-fold lesser extent in the 9L tumor as compared to the unloaded nanospheres and that they were mainly localized in the lungs and the spleen. Such a typical profile indicated aggregation with plasma proteins as a consequence of the positive surface charge of these loaded particles; this ionic interaction resulting from drug encapsulation was mainly responsible for 9L treatment failure.     

WHIM syndromes with different genetic anomalies are accounted for by impaired CXCR4 desensitization to CXCL12

The WHIM syndrome is a rare immunodeficiency disorder characterized by warts, hypogammaglobulinemia, infections, and myelokathexis. Dominant heterozygous mutations of the gene encoding CXCR4, a G-protein-coupled receptor with a unique ligand, CXCL12, have been associated with this pathology. We studied patients belonging to 3 different pedigrees. Two siblings inherited a CXCR4 mutation encoding a novel C-terminally truncated receptor. Two unrelated patients were found to bear a wild-type CXCR4 open reading frame. Circulating lymphocytes and neutrophils from all patients displayed similar functional alterations of CXCR4-mediated responses featured by a marked enhancement of G-protein-dependent responses. This phenomenon relies on the refractoriness of CXCR4 to be both desensitized and internalized in response to CXCL12. Therefore, the aberrant dysfunction of the CXCR4-mediated signaling constitutes a common biologic trait of WHIM syndromes with different causative genetic anomalies. Responses to other chemokines, namely CCL4, CCL5, and CCL21, were preserved, suggesting that, in clinical forms associated with a wild-type CXCR4 open reading frame, the genetic anomaly might target an effector with some degree of selectivity for the CXCL12/CXCR4 axis. We propose that the sustained CXCR4 activity in patient cells accounts for the immune-hematologic clinical manifestations and the profusion of warts characteristic of the WHIM syndrome.     

Effect of chrysin and natural coumarins on UGT1A1 and 1A6 activities in rat and human hepatocytes in primary culture

Flavonoids and coumarins are naturally occurring compounds that are widely distributed in vegetables and have a broad pharmacological activity. Inducibility of UDP-glucuronosyltransferases (UGTs) by xenobiotics is well documented and can be considered beneficial for health. In particular, UGT1A1-dependent bilirubin conjugation plays a critical role in the detoxification of neurotoxic bilirubin and phenobarbital-mediated UGT1A1 induction therapy is commonly used in the treatment of unconjugated hyperbilirubinemic diseases such as Crigler-Najjar type II disease. In the present study, the effects of the flavone chrysin and six natural coumarins isolated from various Rutaceous plants on UGT1A6-dependent P-nitrophenol and/or UGT1A1-dependent bilirubin glucuronoconjugation activities were evaluated in cultured rat and human hepatocytes and compared to those of the prototypical UGT1A inducers beta-naphthoflavone, phenobarbital and clofibric acid. After 3 days of treatment at a concentration of 25 microM, the pyranocoumarins avicennin and CIS-avicennol, and the furocoumarins bergapten and imperatorin, increased by 2-fold UGT1A1-dependent activity, equivalent to the increases obtained with chrysin at 25 microM, whereas in the presence of the simple coumarins such as coumarin or umbelliferone, UGT1A1-dependent activity was not modified. In terms of structural requirements for UGT1A1 induction, the present study suggests that the B-ring (phenyl) for chrysin and the furan or pyran rings for coumarins are essential for the biological activity.     

Impact of serum on clearance predictions obtained from suspensions and primary cultures of rat hepatocytes.

The objective of the present study was to compare two configurations of the hepatocyte model namely suspensions (SH) and conventional primary cultures (CPC) for their ability to predict the hepatic clearance in vivo in the rat and, to investigate the impact of serum on the prediction accuracy. The metabolic competences of several cytochrome P450 isoenzymes were investigated both in CPC and SH in the presence or absence of serum. Under the same conditions, the in vitro intrinsic clearance of six test compounds metabolised by a variety of phase I and phase II enzymes (antipyrine, RO-X, mibefradil, midazolam, naloxone and oxazepam) were derived from Vmax/Km scaled up to the corresponding in vivo hepatic metabolic clearance. CYP activities were shown to be stable in both CPC and SH for up to 6 h of incubation, except for the CYP 3A1 activity that decreased in CPC even in the presence of serum. Moreover, the clearances predicted from SH in the presence of serum were closer to the in vivo values than those obtained from CPC. SH represent a convenient model to assess the hepatic metabolism of xenobiotics, the presence of serum in the incubation medium significantly improved in several instances the quality of the predictions.     

Nab-paclitaxel plus gemcitabine for metastatic pancreatic adenocarcinoma after Folfirinox failure: an AGEO prospective multicentre cohort

Background:

There is currently no standard second-line treatment for metastatic pancreatic adenocarcinoma (MPA), and progression-free survival is consistently <4 months in this setting. The aim of this study was to evaluate the efficacy and tolerability of Nab-paclitaxel plus gemcitabine (A+G) after Folfirinox failure in MPA.

Methods:

From February 2013 to July 2014, all consecutive patients treated with A+G for histologically proven MPA after Folfirinox failure were prospectively enrolled in 12 French centres. A+G was delivered as described in the MPACT trial, until disease progression, patient refusal or unacceptable toxicity.

Results:

Fifty-seven patients were treated with Nab-paclitaxel plus gemcitabine, for a median of 4 cycles (range 1–12). The disease control rate was 58%, with a 17.5% objective response rate. Median overall survival (OS) was 8.8 months (95% CI: 6.2–9.7) and median progression-free survival was 5.1 months (95% CI: 3.2–6.2). Since the start of first-line chemotherapy, median OS was 18 months (95% CI: 16–21). No toxic deaths occurred. Grade 3–4 toxicities were reported in 40% of patients, consisting of neutropenia (12.5%), neurotoxicity (12.5%), asthenia (9%) and thrombocytopenia (6.5%).

Conclusions:

A+G seems to be effective, with a manageable toxicity profile, after Folfirinox failure in patients with MPA.     

Cytokine profile of myelin basic protein—reactive T cells in multiple sclerosis and healthy individuals

Myelin basic protein (MBP)-reactive T cells have been implicated in the autoimmune pathogenesis of multiple sclerosis (MS). In this study, we examined the cytokine profile of 531 primary MBP-reactive T-cell lines and 72 independently established clones from 32 patients with MS and 18 healthy controls (NS) by using highly sensitive enzyme-linked immunosorbent assays. An increased number of primary T-cell lines producing interferon-γ (IFNγ) and/or interleukin-4 (IL-4) in response to MBP were found in patients with MS compared with controls. No distinct Th1 or Th2 subtypes could be demonstrated among the MBP-reactive clones. IL-4 was more frequently observed among MS-derived clones. Clones derived from MS patients produced increased levels of IL? 2, IL? 4, tumor necrosis factor-α (TNFα), IFNγ, and IL-10, but not IL-6. It is interesting that MBP-reactive T cells from MS patients expressing the disease-associated HLA-DRBI 15 allele produced increased quantities of TNFα, a cytokine suggested to play an important role in inflammation and demyelination. When challenged with either MBP or a bacterial superantigen, the clones expressed similar levels of the proinflammatory cytokine IFNγ. Our study suggests a functional difference in T-cell responses to MBP in patients with MS compared with healthy individuals, and provides further insights into the role of MBP-reactive T cells and their cytokine profile in the inflammatory processes of MS.     

Measurement of von Willebrand factor binding to a recombinant fragment of glycoprotein Ibalpha in an enzyme-linked immunosorbent assay-based method: performances in patients with type 2B von Willebrand disease

Type 2B von Willebrand disease (VWD) is characterised by an increased affinity of von Willebrand factor (VWF) for its platelet receptor glycoprotein Ib (GPIb). This feature is usually studied in vitro by a ristocetin-dependent VWF platelet-binding assay, which has some limitations as it requires [e.g. (radio)-labelled anti-VWF antibodies and normal formaldehyde-fixed platelets]. We, here, extended the applicability of an enzyme-linked immunosorbent assay-based method previously described for the measurement of ristocetin co-factor activity that used a recombinant fragment of GPIb (rfGPIb alpha) and horseradish peroxidase-labelled rabbit anti-human VWF antibodies for measuring the captured ristocetin-VWF complexes on the rfGPIb alpha. Thirty-one type 2B VWD patients from 15 families with eight different known mutations were studied. VWF in plasma from 28 of these patients bound better than normal VWF at 0.2 mg/ml ristocetin, with the ratio, optical density (OD) patient/OD normal pool plasma, higher than 1.8. For two of the three other patients with no enhanced response of plasma VWF, the platelet lysate VWF showed an enhanced binding capacity; for the last patient, the results in other members of the family are unequivocal. We conclude that, this new method for measurement of plasma or platelet VWF-binding capacity offers great advantages for correct type 2B VWD diagnosis.