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.     

Nocturnal excretion of 6-sulphatoxymelatonin in children and adolescents with autistic disorder.

BACKGROUND: Many studies in autistic disorder report sleep problems and altered circadian rhythms, suggesting abnormalities in melatonin physiology. Additionally, melatonin, a pineal gland hormone produced from serotonin, is of special interest in autistic disorder given reported alterations in central and peripheral serotonin neurobiology. METHODS: Nocturnal urinary excretion of 6-sulphatoxymelatonin was measured by radioimmunoassay in groups of children and adolescents with autistic disorder (n = 49) and normal control individuals (n = 88) matched on age, sex, and Tanner stage of puberty. RESULTS: Nocturnal 6-sulphatoxymelatonin excretion rate was significantly and substantially lower in patients with autism than in normal controls (mean +/- SEM, .75 +/- .11 vs. 1.80 +/- .17 microg/hr, p =.0001), and was significantly negatively correlated with severity of autistic impairments in verbal communication and play (p < .05). CONCLUSIONS: These findings indicate clearly that nocturnal production of melatonin is reduced in autism. Further research is warranted in order to understand the mechanisms underlying the lower melatonin production, to assess the impact of altered melatonin on the pathophysiology and behavioral expression of autistic disorder, and to determine the utility of melatonin administration in individuals with autism.     

The treatment of chronic pain in Québec: a study of hospital-based services offered within anesthesia departments

PURPOSE: Little or no information exists on the services that are currently available for the treatment of chronic pain across the different regions of Canada. As a first step, this study documented the hospital-based resources and services offered for the management of chronic non-cancer pain within anesthesia departments in Québec. METHODS: In collaboration with the Association of Anesthesiologists of Québec and the Société québécoise de la douleur, a provincial survey was conducted to assess the availability of services for chronic pain management within hospital-based anesthesia departments along with the volume of clinical activities, staff composition, treatments offered and space facilities. RESULTS: The response rate was 100%. Fifty of the 69 departments (73%) offered services for the management of chronic non-cancer pain but the services were often limited. Twenty-six percent (13/50) of the departments provided some form of multidisciplinary assessment and treatment but only three had a core team comprised of an anesthesiologist, a nurse, a psychologist, and a physical therapist. Examination of patient waiting lists of the surveyed departments revealed disturbing results: approximately 4,500 patients were waiting for their first appointment to see a pain consultant, and nearly 3,000 (67%) had been waiting for nine months or more. CONCLUSION: Although this survey did not include the services offered in departments other than anesthesia, the results show the extent to which the province of Québec is under-resourced for the management of chronic pain patients both in terms of access to treatment and quality of the services offered.     

The use of physical hydrogels of chitosan for skin regeneration following third-degree burns

Skin repair is an important field of the tissue engineering, especially in the case of extended third-degree burns, where the current treatments are still insufficient in promoting satisfying skin regeneration. Bio-inspired bi-layered physical hydrogels only constituted of chitosan and water were processed and applied to the treatment of full-thickness burn injuries. The aim of the study was at assessing whether this material was totally accepted by the host organism and allowed in vivo skin reconstruction of limited area third-degree burns. A first layer constituted of a rigid protective gel ensured good mechanical properties and gas exchanges. A second soft and flexible layer allowed the material to follow the geometry of the wound and ensured a good superficial contact. To compare, highly viscous solutions of chitosan were also considered. Veterinary experiments were performed on pig's skins and biopsies at days 9, 17, 22, 100 and 293, were analysed by histology and immuno-histochemistry. Only one chitosan material was used for each time. All the results showed that chitosan materials were well tolerated and promoted a good tissue regeneration. They induced inflammatory cells migration and angiogenetic activity favouring a high vascularisation of the neo-tissue. At day 22, type I and IV collagens were synthesised under the granulation tissue and the formation of the dermal-epidermal junction was observed. After 100 days, the new tissue was quite similar to a native skin, especially by its aesthetic aspect and its great flexibility.     

TRPC6 channel translocation into phagosomal membrane augments phagosomal function

Defects in the innate immune system in the lung with attendant bacterial infections contribute to lung tissue damage, respiratory insufficiency, and ultimately death in the pathogenesis of cystic fibrosis (CF). Professional phagocytes, including alveolar macrophages (AMs), have specialized pathways that ensure efficient killing of pathogens in phagosomes. Phagosomal acidification facilitates the optimal functioning of degradative enzymes, ultimately contributing to bacterial killing. Generation of low organellar pH is primarily driven by the V-ATPases, proton pumps that use cytoplasmic ATP to load H⁺ into the organelle. Critical to phagosomal acidification are various channels derived from the plasma membrane, including the anion channel cystic fibrosis transmembrane conductance regulator, which shunt the transmembrane potential generated by movement of protons. Here we show that the transient receptor potential canonical-6 (TRPC6) calcium-permeable channel in the AM also functions to shunt the transmembrane potential generated by proton pumping and is capable of restoring microbicidal function to compromised AMs in CF and enhancement of function in non-CF cells. TRPC6 channel activity is enhanced via translocation to the cell surface (and then ultimately to the phagosome during phagocytosis) in response to G-protein signaling activated by the small molecule (R)-roscovitine and its derivatives. These data show that enhancing vesicular insertion of the TRPC6 channel to the plasma membrane may represent a general mechanism for restoring phagosome activity in conditions, where it is lost or impaired.Chronic infection and inflammation in the airways in cystic fibrosis (CF), as well as chronic obstructive pulmonary disease (COPD), tuberculosis, and asthma are now among the most common chronic diseases. Pulmonary infection associated with these diseases has historically been treated with antibiotics that kill bacteria but also select for development of resistance in the pathogen in the chronically infected lung (1, 2). One solution to antimicrobial drug resistance is to target the host rather than the pathogen. This strategy necessitates finding alternative targets or signaling strategies amplifying or restoring bactericidal capacity in the cells charged with the task of resolving chronic infection.Mononuclear phagocytes orchestrate the innate immune response in the lung through the combinatorial interplay between the phagocytic uptake and killing of bacterial invaders, clearance of apoptotic cells, antigen presentation, and secretion of vesicle-bound signaling molecules to recruit help in the resolution of infection. Ionic fluxes across the phagosomal membrane that encloses the pathogen produce a hostile acidic environment developed through the action of a V-ATPase proton translocation. However, a positive intraphagosomal membrane potential generated by proton translocation minimizes the proton content of the phagosome. An influx of Cl⁻ via Cl⁻ channels reduces the membrane potential generated by the proton pump, thereby, allowing maximal acidification of the phagolysosomal compartment, which in turn maximizes the activation of lysosomal degradative enzymes, generation of hypochlorous acid, and consequent bacterial killing (3, 4). We have previously demonstrated that murine alveolar macrophages (AMs) use the anion channel cystic fibrosis transmembrane conductance regulator (CFTR) as a Cl⁻ permeation pathway in the phagosomal membrane. In CF, loss of functional CFTR in the AM alkalinizes the phagosomal lumen and allows antimicrobial-resistant bacterial pathogens to survive macrophage surveillance.Not all tissue macrophages use CFTR as a charge compensation pathway in phagolysosomal acidification (4). In fact, recent data suggest that multiple V-ATPase charge-shunt pathways can exist in diverse macrophage lineages (5) via lysosomal recruitment and membrane insertion upon particle uptake. This observation led us to search for possible alternative charge-shunt pathways in pulmonary macrophages and how they might be activated or targeted to the maturing phagosome. Could a pharmacological tool circumvent the defect in CF AMs and activate alternative pathways to rescue both organellar acidification and bactericidal activity in cells expressing mutations in CFTR? Such a tool might activate parallel charge-shunt pathways used in peritoneal macrophages for maximum acidification, thereby allowing them to clear bacteria independently of CFTR expression as well as amplify the microbicidal response in the presence of functional CFTR. The transport proteins and channels active in peritoneal macrophage bacterial clearance have not been described but may involve a K⁺/H⁺ exchanger important in promoting excitatory synaptic vesicle filling (6) or a cation channel moving positive charge out of the phagolysosomal compartment, as has been suggested for macrophage cell lines (7).We began our investigations pursuing a novel pharmacological strategy to identify compounds that would resolve bacterial infection in the CF lung without the use of antimicrobials. We picked a cellular defect in CF because of the availability of animal models and extended our observations to non-CF human pulmonary cells. We designed screening assays of phagosome function, which could be used in a clinical setting as both diagnostic and investigational tools. We interrogated host function by studying surface receptor-mediated mechanisms that might provide parallel signaling pathways in subcellular organellar function in the resolution of disease.We report that a series of small molecules first identified in chemotherapeutics, (R)-roscovitine [2-(R)-(1-ethyl-2-hydroxyethylamino)-6-benzylamino-9-isopropylpurine] and its derivatives, restore microbicidal function to compromised AMs in CF and enhance function in non-CF cells. The compounds use a G protein-mediated signaling pathway, which results in the mobilization of transient receptor potential canonical-6 (TRPC6) calcium-permeable, nonselective cation channels to the plasma membrane and subsequently to the phagosomal membrane. Members of the TRP channel family have been implicated in a number of critical phagocytic functions, including particle uptake, migration, and reactive oxygen species (ROS) production (5, 8–11). Numerous studies (12–15) have suggested TRP channels as potential targets for the development of therapies in pulmonary inflammation because of their abundant and diverse cellular expression throughout the respiratory tree. Although TRPC6 channels have been previously identified in lung macrophages and shown to be up-regulated in COPD, their precise role in the pathophysiology of the disease is yet to be determined (16). Perhaps more relevant to our study, a TRPC6-mediated Ca²⁺ influx is increased in human CF airway epithelial cells, possibly because of a functional association between CFTR and TRPC6 that is lost in CF (17), with unknown consequences. To our knowledge, this study is the first to associate TRPC6 channels a specific drug-targeting strategy for the resolution chronic pulmonary infection.     

Vaccine-induced tumor regression requires a dynamic cooperation between T cells and myeloid cells at the tumor site

Most cancer immunotherapies under present investigation are based on the belief that cytotoxic T cells are the most important anti-tumoral immune cells, whereas intra-tumoral macrophages would rather play a pro-tumoral role. We have challenged this antagonistic point of view and searched for collaborative contributions by tumor-infiltrating T cells and macrophages, reminiscent of those observed in anti-infectious responses. We demonstrate that, in a model of therapeutic vaccination, cooperation between myeloid cells and T cells is indeed required for tumor rejection. Vaccination elicited an early rise of CD11b⁺ myeloid cells that preceded and conditioned the intra-tumoral accumulation of CD8⁺ T cells. Conversely, CD8⁺ T cells and IFNγ production activated myeloid cells were required for tumor regression. A 4-fold reduction of CD8⁺ T cell infiltrate in CXCR3KO mice did not prevent tumor regression, whereas a reduction of tumor-infiltrating myeloid cells significantly interfered with vaccine efficiency. We show that macrophages from regressing tumors can kill tumor cells in two ways: phagocytosis and TNFα release. Altogether, our data suggest new strategies to improve the efficiency of cancer immunotherapies, by promoting intra-tumoral cooperation between macrophages and T cells.     

High Ki67 expression is a risk marker of invasive relapse for classical lobular carcinoma in situ patients

BackgroundThe clinical management of lobular carcinoma in situ lesions remains challenging. Our aim was to evaluate the risk of relapse for lobular carcinoma in situ (LCIS) patients, diagnosed on mammography performed for microcalcifications and according to proliferation assessed by Ki67 staining.MethodsA series of 47 patient's files with LCIS and followed in our institution were retrospectively selected. All patients underwent lumpectomy without radiation therapy. The expression of E-cadherin, estrogen receptor (ER), progesterone receptor (PR), EGFR and Ki67 were determined. Four different classes were then defined with the following criteria: ER+ and Ki67 ≤ 10%; ER+, Ki67 > 10%; ER?; ER-PR? and EGFR+.ResultsPatient's mean age was 51.3 yrs. The majority of the lesions were classical LCIS (97%). All cases were E-cadherin either negative (71%) or weak and incomplete (29%). Among the 44 evaluable cases, 34 cases were ER or PR positive with KI67 ≤ 10% (79%), 9 cases ER positive with KI67 > 10% (21%), 1 case was ER and PR negative and expressed EGFR. At five years, all patients were alive, 1/34 ER positive and Ki67 low experienced a relapse contrasting with 3 out of 9 ER positive and Ki67 high (3 invasive carcinomas including 2 ductal and 1 lobular) (p = 0.0054).ConclusionIn this retrospective study, we observed a higher risk of relapse associated with a high proliferative activity of classical LCIS. If confirmed in larger series, this observation suggests that radiation therapy or hormonotherapy could be discussed for patients with Ki67 high classical LCIS in order to decrease their risk of relapse.     

Pulse transit time improves detection of sleep respiratory events and microarousals in children

OBJECTIVES: To evaluate the additional information provided by pulse transit time (PTT), a noninvasive tool, when using during polysomnography for the diagnosis of sleep breathing disorders in a pediatric population. MAIN FINDINGS: Respiratory and microarousals events were scored twice. The first scoring was performed using nasal pressure, thermistors, thoracic and abdominal movements, and oxygen saturation. The second scoring, blinded to the first scoring, was performed using PTT in combination with all the other signals. Microarousals were scored once visually on the EEG trace (cortical arousals [CAs]) and once using the PTT signal (autonomic arousals [AAs]) blinded to EEG. For the whole group of 16 children studied (mean age, 9.5 years), there was no significant difference between the respiratory disturbance index (RDI) with or without PTT analysis (22.4 +/- 13.5/h vs 20.4 +/- 14.3/h; not significant [mean +/- SD]). Among the children exhibiting a "without PTT" RDI < 30/h, 5 of 12 children (41.66%) showed a clinically significant >/= 5/h increase in RDI when using PTT. AAs detected by PTT were significantly more frequent than CAs during rapid eye movement (REM) sleep (7.4 +/- 3.9/h vs 3.2 +/- 2.3/h; p < 0.001) and slow wave sleep (SWS) [6.0 +/- 4.3/h vs 0.6 +/- 0.5/h; p < 0.0001]. CONCLUSIONS: The quantification of respiratory effort using PTT improves the detection of respiratory events in children. The detection of microarousals is improved particularly in REM and SWS.