Bone-metastatic prostate carcinoma favors mesenchymal stem cell differentiation toward osteoblasts and reduces their osteoclastogenic potential.

Bone homeostasis is achieved by the balance between osteoclast-dependent bone resorption and osteoblastic events involving differentiation of adult mesenchymal stem cells (MSCs). Prostate carcinoma (PC) cells display the propensity to metastasize to bone marrow where they disrupt bone homeostasis as a result of mixed osteolytic and osteoblastic lesions. The PC-dependent activation of osteoclasts represents the initial step of tumor engraftment into bone, followed by an accelerated osteoblastic activity and exaggerated bone formation. However, the interactions between PC cells and MSCs and their participation in the disease progression remain as yet unclear. In this study, we show that bone metastatic PC-3 carcinoma cells release factors that increase the expression by human (h)MSCs of several known pro-osteoblastic commitment factors, such as α5/ß1 integrins, fibronectin, and osteoprotegerin. As a consequence, as shown in an osteogenesis assay, hMSCs treated with conditioned medium (C(ed) M) derived from PC-3 cells have an enhanced potential to differentiate into osteoblasts, as compared to hMSCs treated with control medium or with C(ed) M from non-metastatic 22RV1 cells. We demonstrate that FGF-9, one of the factors produced by PC-3 cells, is involved in this process. Furthermore, we show that PC-3 C(ed) M decreases the pro-osteoclastic activity of hMSCs. Altogether, these findings allow us to propose clues to understand the mechanisms by which PC favors bone synthesis by regulating MSC outcome and properties.

A specific role of phosphatidylinositol 3-kinase gamma. A regulation of autonomic Ca(2)+ oscillations in cardiac cells.

Purinergic stimulation of cardiomyocytes turns on a Src family tyrosine kinase-dependent pathway that stimulates PLCgamma and generates IP(3), a breakdown product of phosphatidylinositol 4,5-bisphosphate (PIP2). This signaling pathway closely regulates cardiac cell autonomic activity (i.e., spontaneous cell Ca(2+) spiking). PIP2 is phosphorylated on 3' by phosphoinositide 3-kinases (PI3Ks) that belong to a broad family of kinase isoforms. The product of PI3K, phosphatidylinositol 3,4,5-trisphosphate, regulates activity of PLCgamma. PI3Ks have emerged as crucial regulators of many cell functions including cell division, cell migration, cell secretion, and, via PLCgamma, Ca(2+) homeostasis. However, although PI3Kalpha and -beta have been shown to mediate specific cell functions in nonhematopoietic cells, such a role has not been found yet for PI3Kgamma. We report that neonatal rat cardiac cells in culture express PI3Kalpha, -beta, and -gamma. The purinergic agonist predominantly activates PI3Kgamma. Both wortmannin and LY294002 prevent tyrosine phosphorylation, and membrane translocation of PLCgamma as well as IP(3) generation in ATP-stimulated cells. Furthermore, an anti-PI3Kgamma, but not an anti-PI3Kbeta, injected in the cells prevents the effect of ATP on cell Ca(2+) spiking. A dominant negative mutant of PI3Kgamma transfected in the cells also exerts the same action. The effect of ATP was observed on spontaneous Ca(2+) spiking of wild-type but not of PI3Kgamma(2/2) embryonic stem cell-derived cardiomyocytes. ATP activates the Btk tyrosine kinase, Tec, and induces its association with PLCgamma. A dominant negative mutant of Tec blocks the purinergic effect on cell Ca(2+) spiking. Tec is translocated to the T-tubes upon ATP stimulation of cardiac cells. Both an anti-PI3Kgamma antibody and a dominant negative mutant of PI3Kgamma injected or transfected into cells prevent the latter event. We conclude that PI3Kgamma activation is a crucial step in the purinergic regulation of cardiac cell spontaneous Ca(2+) spiking. Our data further suggest that Tec works in concert with a Src family kinase and PI3Kgamma to fully activate PLCgamma in ATP-stimulated cardiac cells. This cluster of kinases provides the cardiomyocyte with a tight regulation of IP(3) generation and thus cardiac autonomic activity.

Phenotypic and functional characterisation of ovine mesenchymal stem cells: application to a cartilage defect model.

BACKGROUND: Multipotent mesenchymal stromal cells (MSC) are of particular interest for their potential clinical use in cartilage engineering, but a consistent model is missing in large animals. OBJECTIVE: In the absence of any detailed study reporting a complete characterisation of the mesenchymal cells isolated from sheep bone marrow, we fully characterised adherent stromal cells and developed a pre-clinical model of cartilage engineering by implantation of autologous MSC in the Merinos sheep. METHODS: Ovine MSC (oMSC) were isolated from bone marrow, expanded and further characterised according to the recently proposed definition of the MSC. The experimental model consists of partial-thickness lesions created in the inner part of the patellae of the posterior legs. Lesions were filled with oMSC with or without chitosan, with or without transforming growth factor (TGF)beta-3, in a fibrin clot. RESULTS: oMSC were shown to display the three main characteristics of MSC: adherence to plastic, phenotypic profile (positive for CD44, CD105, vimentin and negative for CD34 and CD45), and trilineage differentiation potential. We also report two other important functional characteristics of MSC: support of long-term haematopoiesis and immunosuppressive capacity. In vivo, 2 months after implantation the histological analysis revealed chondrocyte-like cells surrounded by a hyaline-like cartilaginous matrix that was integrated to the host cartilage when oMSC were combined with chitosan and TGFbeta-3. CONCLUSIONS: This study provides for the first time a strong characterisation of oMSC and establishes the basis for a model of cartilage engineering in a large animal.

Inositol 1,4,5-trisphosphate directs Ca(2+) flow between mitochondria and the Endoplasmic/Sarcoplasmic reticulum: a role in regulating cardiac autonomic Ca(2+) spiking.

The signaling role of the Ca(2+) releaser inositol 1,4, 5-trisphosphate (IP(3)) has been associated with diverse cell functions. Yet, the physiological significance of IP(3) in tissues that feature a ryanodine-sensitive sarcoplasmic reticulum has remained elusive. IP(3) generated by photolysis of caged IP(3) or by purinergic activation of phospholipase Cgamma slowed down or abolished autonomic Ca(2+) spiking in neonatal rat cardiomyocytes. Microinjection of heparin, blocking dominant-negative fusion protein, or anti-phospholipase Cgamma antibody prevented the IP(3)-mediated purinergic effect. IP(3) triggered a ryanodine- and caffeine-insensitive Ca(2+) release restricted to the perinuclear region. In cells loaded with Rhod2 or expressing a mitochondria-targeted cameleon and TMRM to monitor mitochondrial Ca(2+) and potential, IP(3) induced transient Ca(2+) loading and depolarization of the organelles. These mitochondrial changes were associated with Ca(2+) depletion of the sarcoplasmic reticulum and preceded the arrest of cellular Ca(2+) spiking. Thus, IP(3) acting within a restricted cellular region regulates the dynamic of calcium flow between mitochondria and the endoplasmic/sarcoplasmic reticulum. We have thus uncovered a novel role for IP(3) in excitable cells, the regulation of cardiac autonomic activity.

Specific activation of adenylyl cyclase V by a purinergic agonist.

The present study was designed to investigate whether and how the purinergic stimulation of rat ventricular myocytes modulates the cAMP-dependent pathway. Stimulation of cardiomyocytes with ATPgammaS in the presence of the phosphodiesterase inhibitor IBMX increases by 3-fold intracellular cAMP content. In contrast to beta-adrenergic stimulation, the purinergic stimulation of adenylyl cyclase was not inhibited by activation or enhanced by inhibition of a Gi protein. Forskolin did not potentiate the effect of extracellular ATPgammaS on intracellular cAMP content but the effect of isoproterenol did. Like isoproterenol, the purinergic agonist decreased subsequent ADP-ribosylation of a 45 kDa G(alpha s) by cholera toxin. ATPgammaS also increased cAMP content in neonatal rat cardiomyocytes, a cell type that expresses a long form of Gs protein (alpha(s), 52 kDa) in contrast to adult rat cardiomyocytes that express mostly a short form of Gs protein (alpha(s), 45 kDa). Both purinergic and beta-adrenergic agonists increased cAMP in HEK 293 cells expressing type V adenylyl cyclase while cAMP was only increased by beta-adrenergic stimulation of HEK expressing type IV or VI adenylyl cyclases. Thus, we propose that the purinergic and beta-adrenergic stimulations differentially activate adenylyl cyclase isoforms in rat cardiomyocytes and that adenylyl cyclase V is the specific target of the purinergic stimulation.

Abdominal surgery in chronic hemodialysis patients.

The number of patients with end-stage renal disease who benefit from chronic dialysis is steadily increasing. This study was designed to assess abdominal surgery in chronic hemodialysis (CHD) patients. A 7-year retrospective study was conducted including all the patients on CHD who underwent abdominal surgery in our unit. These patients were separated into an elective and an emergency surgery group. Forty-three patients underwent surgery. In the elective surgery group (18 patients), the most common diseases were colorectal cancer, symptomatic gallbladder stones, and hernia. There was no death related to surgery in this group, and only one patient developed a complication (5%). In the emergency surgery group (25 patients), the most common diseases were mesenteric ischemia and gastrointestinal bleeding from angiodysplasia. Complications occurred in 10 patients (total morbidity rate, 40%), and 6 of them died (mortality rate, 24%). Gastrointestinal elective surgery in patients on CHD can be performed with low morbidity and mortality rates. The emergency group was differentiated by the high prevalence of bleeding from angiodysplasia and mesenteric infarction, as well as its high surgical mortality rate.

[Bronchopulmonary dysplasia and cytomegalovirus pneumonia]. / Dysplasie bronchopulmonaire et pneumopathie à cytomégalovirus.

Hyaline membrane disease (HMD) of premature newborn can lead to bronchopulmonary dysplasia (BPD). We report the observation of a 33 weeks premature newborn with HMD, treated with exogenous surfactant and mechanical ventilation. The patient developed respiratory distress with oxygen dependency initially related to BPD. Because of worsening of respiratory condition after 2 months, despite corticosteroid therapy, further investigation was performed. Cytomegalovirus (CMV) was found in urine and in the pharynx and CMV-pneumonia was diagnosed. Treatment with gancyclovir allowed a rapid regression of symptoms. Association between BPD and CMV-pneumonia has been previously reported but the causal relationship is controversial. In premature newborn, CMV-pneumonia can appear clinically and radiologically like a BPD. When evolution is atypical, with persistence of respiratory distress despite BPD treatment, CMV-pneumonia must be considered as a specific antiviral therapy may be discussed.

[Neonatal accidental burn by isopropyl alcohol]. / Brûlure néonatale accidentelle à l'isopropanol.

Antiseptic solutions are commonly used for skin care but are not always safe. In preterm infants, application of antiseptic solutions can lead to serious burns. We report the case of a premature newborn who developed severe burns at 35 weeks post-conceptional age, after his mother used disposable antiseptic towels containing isopropyl alcohol for his skin care. Burns outcome led to diffuse skin burn and death of the baby. Several cases of isopropyl alcohol poisoning through skin absorption have been reported in neonate and infants. Because of its neonatal toxicity, isopropyl alcohol has been excluded from composition of antiseptic solutions commonly used in neonatology. However, isopropyl alcohol is still available in many housecleaning and cosmetic products, while its toxic effects in children are not clearly mentioned. A specific mention "toxic for infants and children" should appear on mass consumption products containing isopropyl alcohol. Moreover, health workers may individually inform parents about possible hazards of poisoning through skin absorption.

[Warfarin fetopathy]. / Foetopathie coumarinique.

UNLABELLED: We report a case of warfarin embryopathy. This disease affects more than 6% of fetuses exposed in utero to a vitamin K antagonist. OBSERVATION: A child whose mother was treated with acenocoumarol because of a mechanical heart valve presented with signs of warfarin embryopathy. He showed chondrodysplasia punctata with telebrachydactyly, facial dysmorphism with nasal hypoplasia, a cataract, and a bilateral pyeloureteral junction syndrome. COMMENTS: Characteristics of this drug induced embryopathy are reminded, while bearing in mind the conflict of interests between the mother and the fetus. The mechanisms of this embryopathy are debated in light of the recent knowledge concerning fetal metabolism of vitamin K.

[Malignant pertussis in the young infant]. / La coqueluche maligne du petit nourrisson.

UNLABELLED: Pertussis remains in France the first cause of bacterial, infectious death in infant aged 10 days to 2 months. It is especially in this age group that malignant pertussis occurs. CASE REPORT: A 40-day-old infant was admitted in the intensive care unit with symptoms of bronchiolitis along with a 200 bpm permanent tachycardia. He presented a marked leukocytosis with lymphocytosis. On the second day, convulsions and coma occurred, followed rapidly by respiratory failure, with a subsequent deterioration due to the development of severe pulmonary hypertension. Circulatory failure caused the infant's death on the beginning of the 5th day. Pertussis was confirmed by PCR on nasopharyngeal swab. Intra-familial contamination was most likely. COMMENTS: Malignant pertussis is characterized by the very young age of patients, permanent tachycardia sine materia, dyspnea with early respiratory failure, frequent neurological symptoms, severe hyperleukocytosis and hyperlymphocytosis, and deep hyponatremia with oliguria and edema. Mortality remains superior to 75% despite the various treatments and life support measures that have been attempted. Adult pertussis, which represents one third of the cases of prolonged cough in this age group, is the main source of contamination of non-immunized young infants. This mode of transmission stresses the importance of the generalization of pertussis vaccine booster in early adolescence, which is recommended in France since 1998. Its extension towards the adult age is under study.

[Role of beta-2-mimetic agents in the treatment of asthma]. / Place des bêta 2 mimétiques dans le traitement de l'asthme.

Recent modifications of pre existing Beta 2 drugs and new substances with a prolonged bronchodilator effect may improve asthmatic treatment, in term of duration of benefit and compliance to medication. Evaluation of bronchodilation is still debated. When single dose of drug is administered, nycthemeral rhythm, baseline pulmonary function are to be taken in account. In case of long term treatment studies, evaluation of the effects is based upon clinical score, sequential pulmonary function tests, morning and evening peak expiratory flow rates. Risks way be related to be related to beta 2 drugs or concomitant therapy or associated pathology. Indications of dose and route administration are related to asthma severity. Question to state if beta 2 drugs may be considered as prevention treatment. Studies with compounds exhibiting prolonged bronchodilating effect are able to reduce nocturnal asthma, peak flow instability and to improve clinical scores and pulmonary function.

Portal vein stenosis and occlusion stenting after liver transplantation in two adults.

We report two cases of percutaneous transhepatic stenting of the portal vein to treat stenosis and occlusion disclosed 5 and 18 months, respectively, after orthotopic liver transplantation in two adult patients. If long-term patency is satisfactory, this technique should allow long-term management of portal vein stenosis and occlusion without the use of thrombolysis.

Simultaneous activation of p38 MAPK and p42/44 MAPK by ATP stimulates the K+ current ITREK in cardiomyocytes.

Living cells exhibit multiple K(+) channel proteins; among these is the recently reported atypical two-pore domain K(+) channel protein TREK-1. Most K(+) currents are modulated by neurohormones and under various pathological conditions. Here, in rat ventricular cardiomyocytes using the whole-cell patch-clamp technique, we characterize for the first time a native TREK-1-like current (I(TREK)) that is activated by ATP, a purine agonist applied at a micromolar range. This current is sensitive to arachidonic acid, intracellular acidosis, and various K(+) current inhibitors. Reverse transcription-polymerase chain reaction reveals the presence of a TREK-1-like mRNA in rat cardiomyocytes that shows 93% identity with mouse TREK-1. ATP effects are greatly attenuated in the presence of arachidonic acid or HCO(-)(3)-induced intracellular acidosis. Using a series of inhibitors, we further demonstrate that the ATP-induced stimulation of I(TREK) implies the activation of cytosolic phospholipase A(2) and the release of arachidonic acid. These events require the simultaneous involvement of p38 MAPK and p42/44 MAPK, respectively, via a cAMP-dependent protein kinase and a tyrosine kinase pathway, whereas the two MAPKs conjugate to activate a mitogen- and stress-activated protein kinase (MSK-1). Our results thus demonstrate the occurrence of a TREK-1-like current in cardiac cells whose activation by purine agonists implies a dual-MAPK cytosolic pathway.

Identification in humans of HPV-16 E6 and E7 protein epitopes recognized by cytolytic T lymphocytes in association with HLA-B18 and determination of the HLA-B18-specific binding motif.

Human papilloma virus type 16 (HPV-16) is the HPV most frequently associated with cervical carcinoma in humans. For the prevention or treatment of cervical carcinoma, the E6 and E7 oncoproteins appear to be good targets for vaccine-induced cytotoxic T lymphocytes (CTL). Lipopeptide vaccination is an efficient way of stimulating cellular responses. However, to synthesize effective lipopeptides, it is necessary to define which epitopes are immunogenic. In this study we first determined that peptide 80 - 88 of the E6 protein was recognized by CTL from a healthy donor in association with the HLA-B18 molecule. We then defined the HLA-B18 anchoring peptide motif by testing the binding of various short peptides with the HLA-B18 molecule and showed that it was related to the HLA-A1-specific peptide motif. Furthermore, in analyzing the potential E7 epitopes susceptible to associating with HLA-B18, we demonstrated that peptide E7 44 - 52 gave the strongest binding. It could also be recognized by CTL from peripheral blood mononuclear cells (PBMC) of the same healthy donor. Finally, with PBMC from a patient with a cervical intraepithelial neoplasia grade 3, we found CTL which recognized the E6 80 - 88 epitope. We have hence identified two peptides encoded by the E6 and E7 proteins which are presented by the HLA-B18 molecule and could be included in a vaccine against HPV-16.