Study of laser induced temperature variation in silica nanofibers

After presenting a theoretical modelling based on the heat equation, we show two different experiments to measure the laser induced temperature variation in silica nanofibers in air, a direct one and an indirect one based on Brillouin scattering, leading to an estimated value of the convective parameter h.

Gas-pressure tuning of wavelength of photon pair emitted by Four-Wave-Mixing in Nanofibers

We present experimental results demonstrating the possibility to tune the wavelength of the photon pair emitted through four wave mixing in a nanofiber, using the pressure of a gas surrounding the nanofiber. Using Argon, a shift of idler wavelength of -1.1nm/bar is measured demonstrating fine adjustment possibility of emission wavelength, allowing to choose between different WDM channels.

Operating range of efficient Raman converters based on nanofibers immersed in different liquids

We present the operating range of Raman wavelength converters based on silica nanofibers immersed in liquids for the design of all fibered wavelength converters. This range is bounded on the lower limit by the pump energy necessary to reach the Raman threshold and on the upper limit by the laser induced breakdown of the nanofiber. These breakdown energies are measured in the ns regime for different liquids (water, ethanol, isopropanol) and for air. We finally define guidelines that open the way to a new family of low-cost compact and efficient all-fibered Raman converters that can be directly inserted in optical fibered networks with very low losses.

Influence of reduced levels or suppression of sodium nitrite on the outgrowth and toxinogenesis of psychrotrophic Clostridium botulinum Group II type B in cooked ham

Outgrowth and toxinogenesis of Clostridium botulinum Group II (non-proteolytic) type B were studied in cooked ham prepared with different NaNO₂ (ranging from 0 to 80 mg/kg) and sodium chloride (NaCl, ranging from 12 to 19 g/kg) incorporation rates. Cured ground pork batters were inoculated with a cocktail of 3 strains of C. botulinum Group II type B at 3.5 log₁₀ CFU/g, portioned and samples of 50 g were vacuum packed then cooked and cooled based on thermal processing employed by the meat processing industry. These cooked ham model samples were stored under reasonably foreseeable conditions of use and storage i.e. for 14 days at 4 °C, followed by a cold chain break for 1 h at 20 °C then up to 33 days at 8 °C. Storage times and temperatures were used to mimic those commonly encountered along the supply chain. Enumeration of C. botulinum and detection of the botulinum neurotoxin type B (BoNT/B) were performed in triplicate at different storage times. Under these experimental conditions, incorporation rates of NaNO₂ ≥ 30 mg/kg prevented the outgrowth and toxinogenesis of C. botulinum Group II type B in the cooked ham model, regardless of the NaCl concentrations tested. In contrast, total removal of nitrite allowed outgrowth and toxin production during storage of the processed meat product. Results showed that the maximum ingoing amount of nitrite (i.e. 150 mg/kg) that may be added according to the EU legislation (Regulation (EC) No 1333/2008) can be reduced in cooked ham while still ensuring control of C. botulinum Group II type B. According to the multiple factors that could affect C. botulinum behavior in processing meat products, outgrowth and toxin production of C. botulinum should be evaluated on a case by case basis, depending on the recipe, manufacturing process, food matrix and storage conditions.

Oxygen as a key parameter in in vitro dynamic and multi-compartment models to improve microbiome studies of the small intestine?

In vitro digestion and fermentation models are frequently used for human and animal research purposes. Different dynamic and multi-compartment models exist, but none have been validated with representative microbiota in the distal parts of the small intestine. We recently developed a dynamic and multi-compartment piglet model introducing microbiota in an ileum bioreactor. However, it presented discrepancies compared to in vivo data. Recommendations are available to standardize studies in this field. They target the digestion model but include elements of a fermentation model. But no recommendation is given concerning control of the atmosphere. The gastrointestinal tract is generally associated with anaerobiosis to conduct a good fermentation process. In this study, we attempted to improve the ileal microbiota of the piglet model by testing inoculation: real intestinal content vs feces; the latter being generally used for ethical and economical aspects. Results showed a positive effect of using real intestinal content. Fusobacteriia were less abundant in the model, Bacteroidia were better maintained in the colon. But for the ileum, results showed that anoxic conditions in the ileum bioreactor conditioned the microbial profile probably more than the type of inoculum itself, leading to the general conclusion that in vitro dynamic and multi-compartment models probably have to get oxygenated to improve microbiome studies of the small intestine.

Laser-induced breakdown measurements of silica nanofibers in air and immersed in water, ethanol and isopropanol

In this paper we present the first study to our knowledge of Laser-Induced Breakdown (LIB) measurements of silica nanofibers in air and in three liquids for different radii in the ns regime. The experimental protocol is described. A significant number of samples are tested and the results are highly repeatable. We showed that immerging a nanofiber in a liquid substantially enhanced the LIB, the most salient increase having been obtained for nanofibers immersed in water for which the LIB has been almost multiplied by a factor of 2 compared with air. This property offers a new degree of freedom to widen the field of applications of nanofibers, where high peaks powers are needed.

Long-time optical transmittance measurements of silica nanofibers

We perform long-time measurements of the optical silica transmittance during several months in different environments and with different nanofiber lengths. These measurements are repeatable and give guidelines to control and to improve the lifetime and the performances of the nanofiber. The dust particles on the nanofiber surface is the fundamental reason behind its degradation. Enhancing the cleanness conditions of the nanofiber environment makes its lifetime increases significantly (from some hours to some months) and enables to avoid the dramatic decrease of its transmittance even after months. The nanofiber length does not contribute to the nanofiber transmittance degradation. Stabilizing the nanofiber transmittance after its decrease is possible by putting in in a dust free box.

Efficient Raman converter in the yellow range with high spatial and spectral brightness

We present a Raman converter emitting at 583 nm on the second Stokes order of a line of propan-2-ol pumped by a microlaser at 532 nm in the sub-nanosecond regime. We used a mixture of liquids to adapt the transmission band of a photonic bandgap fiber. The internal conversion efficiency is 67% in photon numbers, and the output power is 1.06 mW, corresponding to a maximum peak power of 338 W. The beam delivered by the converter presents a Gaussian spatial structure and a high spectral brightness, typically more than five times higher than supercontinuum sources in this spectral range.

Urinary tract infections in 1- to 3-month-old infants: ambulatory treatment with intravenous antibiotics

OBJECTIVE

The goal was to examine the feasibility of outpatient management for 1- to 3-month-old infants with febrile urinary tract infections.

METHODS

A cohort study was performed with all children 30 to 90 days of age who were evaluated for presumed febrile urinary tract infections in the emergency department of a tertiary-care pediatric hospital between January 1, 2005, and September 30, 2007. Patients were treated with intravenously administered antibiotics as outpatients in a day treatment center unless they met exclusion criteria, in which case they were hospitalized.

RESULTS

Of 118 infants included in the study, 67 (56.8%) were admitted to the day treatment center and 51 (43.2%) were hospitalized. The median age of day treatment center patients was 66 days (range: 33-85 days). The diagnosis of urinary tract infection was confirmed for 86.6% of patients treated in the day treatment center. Escherichia coli was identified in 84.5% of urine cultures; 98.3% of isolates were sensitive to gentamicin. Six blood cultures (10.3%) yielded positive results, 5 of them for E coli. Treatment with intravenously administered antibiotics in the day treatment center lasted a mean of 2.7 days. The mean number of visits, including appointments for voiding cystourethrography, was 2.9 visits. The rate of parental compliance with day treatment center visits was 98.3%. Intravenous access problems were seen in 8.6% of cases. Successful treatment in the day treatment center (defined as attendance at all visits, normalization of temperature within 48 hours, negative control urine and blood culture results, if cultures were performed, and absence of hospitalization from the day treatment center) was obtained for 86.2% of patients with confirmed urinary tract infections.

CONCLUSIONS

Ambulatory treatment of infants 30 to 90 days of age with febrile urinary tract infections by using short-term, intravenous antibiotic therapy at a day treatment center is feasible.

Acetylation of the human T-cell leukemia virus type 1 Tax oncoprotein by p300 promotes activation of the NF-kappaB pathway

The oncogenic potential of the HTLV-1 Tax protein involves activation of the NF-kappaB pathway, which depends on Tax phosphorylation, ubiquitination and sumoylation. We demonstrate that the nuclei of Tax-expressing cells, including HTLV-1 transformed T-lymphocytes, contain a pool of Tax molecules acetylated on lysine residue at amino acid position 346 by the transcriptional coactivator p300. Phosphorylation of Tax on serine residues 300/301 was a prerequisite for Tax localization in the nucleus and correlated with its subsequent acetylation by p300, whereas sumoylation, resulting in the formation of Tax nuclear bodies in which p300 was recruited, favored Tax acetylation. Overexpression of p300 markedly increased Tax acetylation and the ability of a wild type HTLV-1 provirus, but not of a mutant provirus carrying an acetylation deficient Tax gene, to activate gene expression from an integrated NF-kappaB-controlled promoter. Thus, Tax acetylation favors NF-kappaB activation and might play an important role in HTLV-1-induced cell transformation.

High-efficiency single-mode Raman generation in a liquid-filled photonic bandgap fiber

Single-spatial-mode Raman generation in an ethanol-filled photonic bandgap fiber is demonstrated. Due to the limited bandwidth of the fiber, the generation is limited to the first Stokes order only, allowing high generated power without any visible decrease of the conversion efficiency. The realization of these two key properties opens the way to the realization of optimized compact nonlinear wavelength converters that will accommodate a large variety of usable liquids.

Regulation of the human T-cell leukemia virus gene expression depends on the localization of regulatory proteins Tax, Rex and p30II in specific nuclear subdomains

The human T-cell leukemia virus HTLV-1 encodes regulatory proteins, Tax, Rex and p30(II), which are involved in the control of viral gene expression at the transcriptional and post-transcriptional levels. Tax localizes in unique nuclear bodies that contain components of the transcription and splicing complexes. In this work, we studied the relative intracellular localizations of Tax, Rex and p30(II). Run-on transcription assays and immunocytochemistry at light and electron microscopy levels indicated that the Tax nuclear bodies included both de novo transcribed RNA and the RNA polymerase II form that is phosphorylated on its carboxy-terminal domain whereas contacts with chromatin were observed at the periphery of these nuclear bodies. Rex first accumulated in nucleolar foci and then spread across the whole nucleus to display a diffuse and punctuate nucleoplasmic distribution. This distribution of Rex was observed in HTLV-1 transformed lymphocytes and in COS cells expressing the HTLV-1 provirus. Rex colocalized with the cellular export factor CRM-1 in the nucleolar foci as well as in the nucleoplasmic foci that did not overlap with Tax nuclear bodies but were found at the boundaries of the Tax bodies. In addition, we demonstrate that p30(II) interacts with Rex and colocalizes with the Rex/CRM-1 complexes in the nucleoli leading to their clearance from the nucleoplasm. Our results suggest that transcripts originating from Tax-induced activation of gene expression at the boundaries of the Tax bodies are transported out of the nucleus by nucleoplasmic Rex/CRM-1 complexes that are first assembled in nucleolar foci. In addition, p30(II) might exert its negative effect on viral RNA transport by preventing the release of the Rex/CRM-1 complexes from sequestration in nucleolar foci. These data support the idea that the transcriptional and post-transcriptional regulation of HTLV-1 gene expression depends on the concentration of select regulatory complexes at specific area of the nucleus.

Exclusive ubiquitination and sumoylation on overlapping lysine residues mediate NF-kappaB activation by the human T-cell leukemia virus tax oncoprotein

The transcription factor NF-kappaB is critical for the induction of cancer, including adult T-cell leukemia, which is linked to infection by human T-cell leukemia virus type 1 and the expression of its regulatory protein Tax. Although activation of the NF-kappaB pathway by Tax involves its interaction with the regulatory subunit of the IkappaB kinase (IKK) complex, NEMO/IKKgamma, the mechanism by which Tax activates specific cellular genes in the nucleus remains unknown. Here, we demonstrate that the attachment of SUMO-1 to Tax regulates its localization in nuclear bodies and the recruitment of both the RelA subunit of NF-kappaB and free IKKgamma in these nuclear structures. However, this sumoylation step is not sufficient for the activation of the NF-kappaB pathway by Tax. This activity requires the prior ubiquitination and colocalization of ubiquitinated Tax with IKK complexes in the cytoplasm and the subsequent migration of the RelA subunit of NF-kappaB to the nucleus. Thus, the ubiquitination and sumoylation of Tax function in concert to result in the migration of RelA to the nucleus and its accumulation with IKKgamma in nuclear bodies for activation of gene expression. These modifications may result in targets for the treatment of adult T-cell leukemia.

Sorption and redox processes controlling arsenic fate and transport in a stream impacted by acid mine drainage

Reigous acid creek originating from the Carnoulès tailings impoundment supplies high concentrations of arsenic under soluble (up to approximately 4 mg/l) and particulate (up to 150 mgAs/g) phases to the Amous river, situated at the drainage basin of the Rhône river (Southern France). The metalloid is present as As(III) (>95%) in Reigous creek water while As(V) predominates (50-80%) in the solid phase, i.e. schwertmannite. At the confluence between acid (pH<5) creek and alkaline Amous river, As(III) concentrations decrease ten-fold through dilution and formation of As-rich ferrihydrite (As/Fe=0.02-0.1) containing 10-30% As(III). However, these attenuation processes are not efficient in the summer heatwave of 2003 since As concentrations in Amous river water (>or=20 microg/l) and As/Fe ratios in particulate matter (>or=0.07) are closed to those of Reigous creek (<or=22 microg/l and <or=0.02, respectively) or even higher. Downstream the confluence, processes involved in the transport of aqueous As along Amous river flowpath vary seasonally. Arsenic is transported conservatively in the aqueous phase away from the confluence in the cooler months; thus, dilution by unpolluted tributaries is the only process that decreases As concentrations. However, As(III) is rapidly oxidized and As(V) remains in solution. In contrast, during the warm season, desorption from As-rich sediment occurs which results in an increase of As(V) and As(III) concentrations along Amous river flow until they reach up to approximately 20 microg/l each. Therefore, Amous river seems not to be totally recovered from mine-related arsenic contamination after 3.5 km and may affect freshwater resources further downstream.

Pharmacokinetic evaluation of a new oral sustained release dosage form of tramadol

AIMS

To compare the pharmacokinetic profile of a new modified release formulation of tramadol (Tramadol LP 200 mg, SMB Technology, Marche-en-Famenne, Belgium) with that of an immediate release capsule (Topalgic) 50 mg, Grünenthal, Aachen, Germany) after single and multiple dosing and to assess the potential effect of food on its relative bioavailability.

METHODS

The first study had an open, single-dose, three-treatment, three-period, six-sequence, randomised, crossover design with at least a five-day wash-out. The second study had an open, steady-state, two-treatment, two-period, two-sequence, randomised crossover design with at least a seven-day wash-out. Both studies contained 30 healthy subjects. Both enantiomers of tramadol and O-demethyl-tramadol (the only active metabolite of tramadol) were assayed in the plasma using an LC-MS/MS method. AUC infinity, AUCt, Cmax, Tmax, and T1/2 were estimated. Statistical analysis was performed using univariate anova, the Wilcoxon nonparametric method or Friedman's nonparametric anova where appropriate.

RESULTS

Tramadol had a significantly lower Cmax and longer Tmax than the conventional formulation. Thus, the mean (+/- sd) Cmax of tramadol were 646 +/- 192 and 300 +/- 94 ng ml-1 for Topalgic 4 x 50mg and Tramadol LP 200 mg, respectively (95% confidence interval on the difference expressed as a percentage 42-51). AUC of tramadol from both formulations was comparable (similar AUC infinity and AUCt). Thus, the mean AUC infinity of (+/-)tramadol obtained after multiple dosing were 4611 +/- 1944 and 5105 +/- 2101 ngh ml-1 after Topalgic 4 x 50mg and Tramadol LP 200 mg, respectively (95%CI 102-123%). We also demonstrate that the pharmacokinetics of the drug are not influenced by the intake of food. Thus, the mean AUC infinity of (+/-) tramadol were 5444 +/- 1637 and 5169 +/- 1580 ngh ml-1 after Tramadol LP 200 mg given in the fasting and fed states, respectively (95%CI = 88-103%).

CONCLUSIONS

The new sustained release form of tramadol exhibits adequate properties for once a day administration. Furthermore, its pharmacokinetic profile is not affected by the intake of food.

Immobilization of arsenite and ferric iron by Acidithiobacillus ferrooxidans and its relevance to acid mine drainage

Weathering of the As-rich pyrite-rich tailings of the abandoned mining site of Carnoulès (southeastern France) results in the formation of acid waters heavily loaded with arsenic. Dissolved arsenic present in the seepage waters precipitates within a few meters from the bottom of the tailing dam in the presence of microorganisms. An Acidithiobacillus ferrooxidans strain, referred to as CC1, was isolated from the effluents. This strain was able to remove arsenic from a defined synthetic medium only when grown on ferrous iron. This A. ferrooxidans strain did not oxidize arsenite to arsenate directly or indirectly. Strain CC1 precipitated arsenic unexpectedly as arsenite but not arsenate, with ferric iron produced by its energy metabolism. Furthermore, arsenite was almost not found adsorbed on jarosite but associated with a poorly ordered schwertmannite. Arsenate is known to efficiently precipitate with ferric iron and sulfate in the form of more or less ordered schwertmannite, depending on the sulfur-to-arsenic ratio. Our data demonstrate that the coprecipitation of arsenite with schwertmannite also appears as a potential mechanism of arsenite removal in heavily contaminated acid waters. The removal of arsenite by coprecipitation with ferric iron appears to be a common property of the A. ferrooxidans species, as such a feature was observed with one private and three collection strains, one of which was the type strain.

First synthesis and pharmacological evaluation of benzoindolizidine and benzoquinolizidine analogues of alpha- and beta-peltatin

The benzoindolizidine and quinolizidine analogues of alpha- and beta-peltatin were designed and synthesized by two different synthetic routes involving as the key step the Bischler-Napieralski cyclization of suitably substituted N-acyl-2-arylmethylpyrrolidine and -piperidine derivatives. The in vitro biological activity of these analogues as well as some of their derivatives was subsequently evaluated.

Characterization of methylation site of monomethylflavan-3-ols by liquid chromatography/electrospray ionization tandem mass spectrometry

Liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) was used for the structural characterization and differentiation of four isomeric O-monomethylated catechins (on phenolic positions) by the analysis of the fragmentation behaviour of catechin. The catechin fragmentation routes were rationalized and it is shown that several diagnostic ions such as (1,3)A(+), (1,2)B(+), and (1,4)B(+) allow the unambiguous identification of the methylated ring. The precise position of the methyl group on each ring is determined by the difference in the relative intensities of the diagnostic ions. Isomeric O-methylepicatechins were also differentiated using this methodology.

Hydroxylamine-induced cleavage of the asparaginyl-glycine motif in the production of recombinant proteins: the case of insulin-like growth factor I

Hydroxylamine-induced cleavage at the asparaginyl-glycine dipeptide site inserted between the two moieties of recombinant fusion proteins has been used at both the analytical and the preparative scale to obtain the mature protein. In this study a model protein containing a fusion precursor of insulin-like growth factor I was used to investigate the influence of the operating conditions on the cleavage reaction and the formation of undesired side products such as hydroxamate and deamidated analogs. Moreover, the stability of the cleavage site toward deamidation was examined and a chemometric study performed to define the effect of the reaction conditions on the cleavage yield and on the formation of side products.

Clinical and genetic study of chronic (types II and III) childhood onset spinal muscular atrophy

We have conducted a retrospective study of 63 patients affected by chronic forms of spinal muscular atrophy (SMA) to better document the natural history of this disease. Thirty-nine patients had type II and 24 type III SMA. These patients had manual muscle testing (MMT) and forced vital capacity (FVC) studies done every six to 12 months over follow up period ranging from six to 140 months. A decline in FVC was seen in both types of SMA but there was no significant change in MMT in either group. Genetic studies were also done in a subset of 17 families (23 patients) included in this study. Homozygous deletions in the telomeric survival motor neuron (SMN) and the neuronal apoptosis inhibitory protein (NAIP) genes were observed in 100% and 11.8% of the patients tested respectively.

[Action of betaxolol on ventricular arrhythmias. Control of efficacy and tolerance by repetitive Holter recordings]

The ventricular anti-arrhythmic action of 20 mg of betaxolol per day was evaluated in 14 patients treated in monotherapy for a fortnight, by means of repeated Holter recordings. A significant decrease in the number of ischemic ventricular extrasystoles was observed during the diurnal and nocturnal periods. Repetitive ventricular events were also reduced. Betaxolol therefore appears to have a direct anti-arrhythmic action which is not related to its action on the heart rate. The other effects of beta-blocker treatment were also observed: a decrease in the systolic and diastolic blood pressure and sinus bradycardia.

[Retrospective analysis of a series of 330 Holter recordings. Diagnostic value of the method and correlation with symptomology]

We have studied a series of 330 Holter recordings (HR) (including 5 double observations) 189 men and 136 women, mean age 58,4 years Old. The analysis of this series shows that: --105 HR were performed on patients with focal ischemia attacks of suputed embolic origin; the HRT was positive in 35 patients (33 p. 100) with 25 supraventricular arrhythmias (SVA) 16 ventricular arrhythmias, associated in 9 cases, and 3 conduction blocks second degrees type 2. These arrhythmias are rare in patients under 40, increasing with age, and reaching 53 p. 100 in patients greater than 70 years. --86 HR were performed in ischemic heart disease (IHD): 52 HR for ST segment analysis, positive in 5 cases, and coexisting with chest pain in 4 cases; 34 HR for detecting arrhythmias in IHD, positive in 18 cases with 14 VA and 4 SVA. In 83 p. 100 the arrhythmias occur without IHD. They were positive in 70 cases, with 49 SVA, 34 VA, associated in 17 cases, and 4 blocks second degrees type 2. --10 cardiomyopathies were recorded; the HR was positive in 6, with 4 SVA, 3 VA associated in 1 case. --8 mitral valve prolapses were recorded with 5 VA and 1 SVA. In conclusion, the HR was positive in 45 p. 100 of the cases, and show especially the great incidence of asymptomatic VA in patients with IHD.