ATP release from human airway epithelial cells studied using a capillary cell culture system

Epithelial release of adenosine triphosphate (ATP), an important autocrine and paracrine signalling molecule, is acutely mechanosensitive and therefore difficult to study. We describe here a novel preparation that minimizes mechanical and metabolic perturbations, and use it to examine ATP secretion by epithelial cells. The Calu-3 cell line derived from human airway sub-mucosal glands was cultured in a hollow fibre bioreactor on porous capillaries that were perfused by a re-circulating medium pump. Cells became polarized and cultures were stable for > 5 months, as evidenced by microscopy and lactate production (≈250 μg (10⁸ cells)⁻¹ day⁻¹). Elevating apical flow rate 5-fold increased ATP secretion from ≈200 to 6618 fmol min⁻¹. Reducing apical osmolarity by 25–43 % also increased ATP secretion, which then declined spontaneously to a plateau rate that persisted as long as hypotonic perfusion was maintained. Release deactivated rapidly after shear and osmotic stresses were terminated, and was not associated with detectable cell lysis. Lowering apical [Ca²⁺] to increase connexin hemichannel permeability also stimulated ATP release and increased secretion during both hyposmotic and shear stress; however, the connexin 43 blocker flufenamic acid inhibited shear-induced ATP release only in low-Ca²⁺ solution, and therefore another secretory pathway may operate with physiological (i.e. m m ) calcium. Regardless of the mechanism, the present results quantify ATP responses to mechanical and osmotic stimuli and demonstrate the usefulness of capillary cultures for studying epithelial secretion.     

Novel antiepileptic drug levetiracetam decreases dyskinesia elicited by L-dopa and ropinirole in the MPTP-lesioned marmoset.

Long-term dopamine replacement therapy of Parkinson's disease leads to the occurrence of dyskinesias. Altered firing patterns of neurons of the internal globus pallidus, involving a pathological synchronization/desynchronization process, may contribute significantly to the genesis of dyskinesia. Levetiracetam, an antiepileptic drug that counteracts neuronal (hyper)synchronization in animal models of epilepsy, was assessed in the MPTP-lesioned marmoset model of Parkinson's disease, after coadministration with (1) levodopa (L-dopa) or (2) ropinirole/L-dopa combination. Oral administration of levetiracetam (13-60 mg/kg) in combination with either L-dopa (12 mg/kg) alone or L-dopa (8 mg/kg)/ropinirole (1.25 mg/kg) treatments was associated with significantly less dyskinesia, in comparison to L-dopa monotherapy during the first hour after administration. Thus, new nondopaminergic treatment strategies targeting normalization of abnormal firing patterns in basal ganglia structures may prove useful as an adjunct to reduce dyskinesia induced by dopamine replacement therapy without affecting its antiparkinsonian action.     

Pseudotumoral organization of a twisted epiploic fringe or 'hard-boiled egg' in the peritoneal cavity.

A freely moving pseudotumoral formation resembling a peeled "hard-boiled egg" was discovered in the abdominal cavity of an 82-year-old male patient during exploratory laparotomy for assessment of hepatocarcinoma in the left lobe of the liver. The formation involved a twisted epiploic fringe, which was necrotic, sclerotic, and calcified. The absence of any attachment and the avascular aspect of this pseudotumor suggest a possibly self-sustaining mechanism for the laminar sclerosis organized around the necrotic adipose tissue.     

High responsiveness of HLA-B57-restricted Gag-specific CD8+ T cells in vitro may contribute to the protective effect of HLA-B57 in HIV-infection

HLA-B57 has been shown to be associated with long-term asymptomatic HIV-1 infection. To investigate the biological mechanism by which the HLA-B57 allele could protect from HIV-1 disease, we studied both the number of CD8(+) T cells as well as CD8(+) T cell responsiveness directed to different HIV-1 Gag peptides presented by HLA-A2, -B8 or -B57. T cells specific for the HLA-B57 peptide KAFSPEVIPMF responded more readily and to a higher extend to antigenic stimulation in vitro than T cells specific for the HLA-A2 peptide SLYNTVATL or the HLA-B8 peptide EIYKRWII. This phenomenon was reproducible with T cells from individuals expressing HLA-B57 in combination with one or both of the other alleles and was persistent during long-term follow-up. Lower reactivity of A2- and B8-restricted T cells was not explained by mutations in the B8- or A2-restricted Gag-peptides. Moreover, no correlation between peptide mutation frequency and IFN-gamma production by the corresponding Gag-specific T cells was observed. In conclusion, functional differences were observed between T cells specific for HIV epitopes derived from the same protein presented by different HLA molecules. B57-restricted KAFSPEVIPMF-specific CD8(+) T cells have relatively high responsiveness, which could contribute to the protective effect of HLA-B57 in HIV infection.     

Pneumocystis carinii f. sp. hominis is not infectious for SCID mice

The infectious power of Pneumocystis carinii f. sp. hominis was explored by inoculating SCID mice intranasally with either P. carinii f. sp. hominis or P. carinii f. sp. muris isolates. Only mice inoculated with mouse parasites developed Pneumocystis pneumonia, as assessed by microscopy and PCR. These results suggest that humans do not contract pneumocystosis from animals.     

Molecular characterization of Cryptosporidium isolates obtained from humans in France

Cryptosporidium parvum is usually considered the agent of human cryptosporidiosis. However, only in the last few years, molecular biology-based methods have allowed the identification of Cryptosporidium species and genotypes, and only a few data are available from France. In the present work, we collected samples of whole feces from 57 patients from France (11 immunocompetent patients, 35 human immunodeficiency virus [HIV]-infected patients, 11 immunocompromised but non-HIV-infected patients) in whom Cryptosporidium oocysts were recognized by clinical laboratories. A fragment of the Cryptosporidium 18S rRNA gene encompassing the hypervariable region was amplified by PCR and sequenced. The results revealed that the majority of the patients were infected with cattle (29 of 57) or human (18 of 57) genotypes of Cryptosporidium parvum. However, a number of immunocompromised patients were infected with C. meleagridis (3 of 57), C. felis (6 of 57), or a new genotype of C. muris (1 of 57). This is the first report of the last three species of Cryptosporidium in humans in France. These results indicate that immunocompromised individuals are susceptible to a wide range of Cryptosporidium species and genotypes.     

Synthèse et polymérisation de monomères acryliques fluorés substitués en position α, 4. Applications à l'α-acétoxyacrylate et à l'α-propionyloxyacrylate de 2-perfluorooctyléthyle

The synthesis of the two monomers 2-perfluorooctylethyl α-acetoxyacrylate ( 1 ) and 2-perfluorooctylethyl α-propionyloxyacrylate ( 2 ) was performed in two steps starting from ethyl pyruvate and 2-perfluorooctylethanol with overall yields of about 56% and 50%, respectively. Transesterification of ethyl pyruvate with the adequate fluorinated alcohol followed by enol acylation gave 1 and 2 , respectively. The kinetic study of polymerization of monomers 1 and 2 , led to the determination of the values of the ratio of the square of the rate constant of propagation over the rate constant of termination k²_p/k_te equal to 9,2 · 10^?3 and 9,1 · 10^?3 L · mol^?1 ·s^?1, respectively, and were compared to those of commercially available fluorinated acrylates and methacrylates.     

Percutaneous versus surgical tracheostomy: a double-blind randomized trial

OBJECTIVE: To compare surgical (SgT) and percutaneous (PcT) tracheostomies. BACKGROUND: Percutaneous tracheostomy has been said to provide numerous advantages over classical SgT. METHODS: A prospective randomized trial with a double-blind evaluation was used to compare SgT and PcT. SgT and PcT were performed according to established techniques (n = 70). The procedure was performed at the bedside in the intensive care unit in 21 cases (30%). The outcome measures were divided into procedure-related variables, perioperative complications, and postoperative complications. The procedure-related variables (location, duration, and difficulty) were evaluated by the surgeon. The perioperative and postoperative complications were divided into serious, intermediate, and minor. Perioperative and early postoperative (14 days) complications were evaluated daily by an intensive care unit nurse blinded to the technique used. Long-term postoperative complications were evaluated 3 months after decannulation by a surgeon blinded to the surgical technique. RESULTS: There were no major complications in either group. Most variables studied were not statistically different between the PcT and SgT groups. The only variables to reach statistical significance were the size of the incision (smaller with PcT, p < 0.0001), minor perioperative complications (greater with PcT, p = 0.02), and difficult cannula changes (greater with PcT; p < 0.05). Among nonsignificant differences, difficult procedures and false passages were more frequent with PcT, whereas long-term unesthetic scars were more frequent with SgT. CONCLUSIONS: Both techniques are associated with a low rate of serious or intermediate complications when performed by experienced surgeons. There were more minor perioperative complications with PcT and more minor long term complications with SgT.