Assay method for the perfluorooctyl bromide (perflubron) in rat blood by gas chromatography-mass spectrometry

This paper describes a GC-MS method (SIM mode) for the analysis of perfluorooctyl bromide (perflubron, I) in rat blood. The chromatographic separation was performed by injection in the split mode using a CP-select 624 CB capillary column. Following destruction of the emulsion by addition of ethanol, the analytical procedure involves a liquid-liquid extraction with 1,1,2-trichlorotrifluoroethane. The bis(F-butyl)ethene (II) was used as internal standard. Observed retention times were 3.22 min for I and 2.32 min for II. Two calibration curves were used; linear detection responses were obtained for concentrations ranging from 0.009 to 0.9 mg/ml and from 0.9 to 13.5 mg/ml. The extraction efficiency averaged 50% for I and 93% for II. Precision ranged from 0.7 to 14%, and accuracy was between 91 and 109%. The limit of quantification was 9 microg/ml. The method validation results indicate that the performance characteristics of the method fulfilled the requirements for assay method for use in pharmacokinetic studies.     

Jeune syndrome and liver disease: report of three cases treated with ursodeoxycholic acid

Evidence for a bipolar disorder (BPD) susceptibility locus on chromosome 22q11 has been provided in several studies. One candidate gene that maps to this region is the G-protein alpha subunit gene Galphaz (GNAZ). We have identified a common silent polymorphism in GNAZ exon 2 by single strand conformation polymorphism analysis. The frequency of this polymorphism was determined in a control population (n=84) and in patients with BPD (n=88). The data showed a statistical trend toward a difference in the distribution of alleles in patients with BPD compared with control subjects (chi square=3.2, 1 df, P=0.073, two-tailed). No significant difference was detected when the GNAZ polymorphism was analyzed in control subjects and schizophrenia patients (n=63, P=0.92). These data continue to provide some support for a BPD susceptibility gene on 22q11, possibly in linkage disequilibrium with the GNAZ 309 polymorphism.     

Ultrastructural determinants of murine achilles tendon strength during healing

The mechanisms by which tendon strength is established during growth and development and restored following injury are not completely understood and are likely to be complex, multifactorial processes. Several studies examining the relationship between mechanical behavior and ultrastructural characteristics of tendons and ligaments during growth and maturation suggest that collagen fibril diameter is strongly correlated with tendon strength. Because of the similarities between development and repair processes of musculoskeletal tissues, increases in tendon strength during healing may be related to increases in fibril ultrastructural parameters such as fibril size, numerical density, and area fraction. In this study, we compared murine Achilles tendons at various time points after tenotomy with sham-operated controls in tensile tests to failure and examined tendons using electron microscopy to assess collagen fibril ultrastructure. We found that in the 6-week period following Achilles tenotomy, fibril mean diameter remained significantly smaller than sham-side diameter by a factor of 2-3. Despite the persistently small fibril size, increasing numerical density resulted in a gradual increase in fibril area fraction. Biomechanical strength did not reach that of intact tendons until some time between 5 and 7 weeks, approximately the same time period when fibril area fraction began to approach sham values. These data suggest that parameters other than collagen fibril size are most responsible for increased tendon strength during healing.     

Diagnosis of imported malaria with multiplex PCR on LighCycler apparatus

For the diagnosis of imported malaria, a competitive multiplex PCR using LightCycler was developed and compared for 3 months with a traditional PCR method. Hundred eighty three patients were tested by these 2 techniques of molecular diagnosis: 60 were positive for P. falciparum, 9 were positive for other Plasmodium species and 114 were negative. The LightCycler method was found in total agreement with the traditional PCR.     

High-intensity intermittent running training improves pulmonary function and alters exercise breathing pattern in children

We investigated the effects of short duration running training on resting and exercise lung function in healthy prepubescent children. One trained group (TrG) (n = 9; three girls and six boys; age = 9.7 ± 0.9 year) participated in 8 weeks of high-intensity intermittent running training and was compared to a control group (ContG) (n = 9; four girls and five boys; age = 10.3 ± 0.7 year). Before and after the 8-week period, the children performed pulmonary function tests and an incremental exercise test on a cycle ergometer. After the 8-week period, no change was found in pulmonary function in ContG. Conversely, an increase in forced vital capacity (FVC) (+7 ± 4% ; P = 0.026), forced expiratory volume in one second (+11 ± 6% ; P = 0.025), peak expiratory flows (+17 ± 4% ; P = 0.005), maximal expiratory flows at 50% (+16 ± 10% ; P = 0.019) and 75% (+15 ± 8% ; P = 0.006) of FVC were reported in TrG. At peak exercise, TrG displayed higher values of peak oxygen consumption (+15 ± 4% ; P<0.001), minute ventilation (+16 ± 5% ; P = 0.033) and tidal volume (+15 ± 5% ; P = 0.019) after training. At sub-maximal exercise, ventilatory response to exercise was lower (P = 0.017) in TrG after training, associated with reduced end-tidal partial oxygen pressure (P<0.05) and higher end-tidal partial carbon dioxide pressure (P = 0.026). Lower deadspace volume relative to tidal volume was found at each stage of exercise in TrG after training (P<0.05). Eight weeks of high-intensity intermittent running training enhanced resting pulmonary function and led to deeper exercise ventilation reflecting a better effectiveness in prepubescent children.     

Saccharomyces boulardii interferes with enterohemorrhagic Escherichia coli-induced signaling pathways in T84 cells

Enterohemorrhagic Escherichia coli (EHEC) infections are associated with the modification of tight-junction permeability and synthesis of proinflammatory cytokine interleukin-8 (IL-8). In a previous study, it was demonstrated that EHEC-induced IL-8 secretion is due to the involvement of the mitogen-activated protein kinase (MAPK), AP-1, and NF-kappaB pathways. In this study, we investigated the effect of the yeast Saccharomyces boulardii on EHEC infection in T84 cells. For this purpose, cells were (i) incubated with bacteria and yeast at the same time or (ii) incubated overnight with yeast cells that were maintained during infection or eliminated by several washes before infection. Coincubation is sufficient to maintain the transmonolayer electrical resistance (TER) of EHEC-infected cells, whereas the preincubation of cells with the yeast without elimination of the yeast during infection is necessary to significantly decrease IL-8 secretion. We thus analyzed the mechanisms of S. boulardii action. We showed that S. boulardii has no effect on EHEC growth or on EHEC adhesion. Kinetics studies revealed that EHEC-induced myosin light chain (MLC) phosphorylation precedes the decrease of TER. ML-7, an MLC kinase inhibitor, abolishes the EHEC-induced MLC phosphorylation and decrease of TER. Studies show that S. boulardii also abolishes EHEC-induced MLC phosphorylation. We demonstrated that the preincubation of cells with S. boulardii without washes before EHEC infection inhibits NF-kappaB DNA binding activity, phosphorylation and degradation of IkappaB-alpha, and activation of the three members of a MAPK group (extracellular signal-regulated protein kinases 1 and 2, p38, and c-jun N-terminal kinase). These findings demonstrate that S. boulardii exerts a preventive effect on EHEC infection by (i) interfering with one of the transduction pathways implicated in the control of tight-junction structure and (ii) decreasing IL-8 proinflammatory secretion via inhibition of the NF-kappaB and MAPK signaling pathways in infected T84 cells.     

Contribution of BK Ca2+-activated K+ channels to auditory neurotransmission in the Guinea pig cochlea

Large-conductance calcium-activated potassium (BK) channels are known to play a prominent role in the hair cell function of lower vertebrates where these channels determine electrical tuning and regulation of neurotransmitter release. Very little is known, by contrast, about the role of BK channels in the mammalian cochlea. In the current study, we perfused specific toxins in the guinea pig cochlea to characterize the role of BK channels in cochlear neurotransmission. Intracochlear perfusion of charybdotoxin (ChTX) or iberiotoxin (IbTX) reversibly reduced the compound action potential (CAP) of the auditory nerve within minutes. The cochlear microphonics (CM at f1 = 8 kHz and f2 = 9.68 kHz) and their distortion product (DPCM at 2f1-f2) were essentially not affected, suggesting that the BK specific toxins do not alter the active cochlear amplification at the outer hair cells (OHCs). We also tested the effects of these toxins on the whole cell voltage-dependent membrane current of isolated guinea pig inner hair cells (IHCs). ChTX and IbTX reversibly reduced a fast outward current (activating above -40 mV, peaking at 0 mV with a mean activation time constant tau ranging between 0.5 and 1 ms). A similar block of a fast outward current was also observed with the extracellular application of barium ions, which we believe permeate through Ca2+ channels and block BK channels. In situ hybridization of Slo antisense riboprobes and immunocytochemistry demonstrated a strong expression of BK channels in IHCs and spiral ganglion and to a lesser extent in OHCs. Overall, our results clearly revealed the importance of BK channels in mammalian cochlear neurotransmission and demonstrated that at the presynaptic level, fast BK channels are a significant component of the repolarizing current of IHCs.     

Characterisation of bioactive and resorbable polylactide/Bioglass composites by FTIR spectroscopic imaging

Formation, size and distribution of hydroxyapatite domains in resorbable composites made of poly(DL-lactide) foams and Bioglass particles after exposure to a solution of phosphate-buffer saline (PBS) for different periods of time have been analysed with FTIR imaging using the micro-ATR-IR approach. The spectral information of 4096 spectra measured simultaneously with the IR microscope equipped with a focal plane infrared array detector allowed us to obtain chemical images showing the distribution of Bioglass particles in the composites. FTIR imaging in micro-ATR mode allowed to obtain images with enhanced spatial resolution. A random distribution of hydroxyapatite domains with average size of ca. 10 microm on the surface of the composites was found after exposure to PBS for 14 and 28 days. The further growth of the hydroxyapatite domains after exposure to PBS for 63 days was detected. The spectroscopic imaging method introduced here promises to become a powerful method for characterisation of resorbable polymer composites containing bioactive inorganic phases developed for bone tissue engineering scaffolds. The accurate detection of hydroxyapatite domains and the imaging of their location in the scaffold structure is required to provide an assessment of the composites bioactivity.     

Synthèse de polystyrènes chlorométhylés renfermant des radicaux tétrathiafulvalénylphénoxyméthyles

In order to study the influence of the nature of the moiety bearing a tetrathiafulvalenyl group in the polymers upon the microlithographic properties of resists, poly(p-chloromethylstyrene)s and poly(styrene-co-p-chloromethylstyrene)s containing the 4-tetrathiafulvalenylphenoxymethyl group with a variety of controlled molecular weights and molecular weight distributions were studied. The copolymers were all prepared by reaction of poly(4-vinylbenzyl chloride) with potassium 4-tetrathiafulvalenylphenolate ( 3 ). Without exception, the resulting poly[p-chloromethylstyrene-co-p-(tetrathiafulvalenylphenoxymethyl)styrene]s are highly insoluble. However, by reaction of potassium 4-tetrathiafulvalenylphenolate with poly(styrene-co-p-chloromethylstyrene) soluble copolymers could be prepared.     

Tumor antigens and antigen-presenting capacity in breast cancer.

AIMS: Cancer cells frequently express antigens capable of being recognized by the host immune system; however, any resultant immune response is often ineffective. This may be related in part to tumor-induced defects in antigen presentation. We screened for dendritic cell infiltration, tumor MHC II expression and associated lymphocytic reaction in the context of three established breast tumor antigens. METHODS: Forty primary breast tumors were evaluated by immunohistochemical techniques for expression of her2/neu, p53, and MUC1 and MHC class II molecules. Twenty-five samples were further analyzed for p53 mutations by PCR-SSCP analysis and DNA sequencing. The phenotype of tumor-infiltrating inflammatory cells was evaluated using the following markers: CD1a, MHC Class II, CD3, CD45, and CD45RO. RESULTS: Tumors with p53 mutations and overexpression, but not her2/neu or MUC1 overexpressing tumors, more frequently harbored marked CD1a+ dendritic cell infiltrates. An overall correlation between CD1a+ cell infiltrates and HLA class II expression on tumor cells (p = 0.0008) was also observed and these tumors had greater CD45RO+ lymphocytic infiltrates. CONCLUSIONS: In breast cancer, p53 mutations may present a more visible signal to the immune system and hence provide a better target for immunotherapy. Infiltrating CD1a positive cells are associated with a more dense tumor lymphocytic infiltrate and tumor cell expression of MHC II molecules.