Anti-inflammatory properties of bone morphogenetic protein 4 in human adipocytes.

BACKGROUND: Obesity is characterized by increased adipocyte number and size as well as white adipose tissue (WAT) inflammation, which is fundamental for the development of insulin resistance and type-2 diabetes. These processes, regulated by various endocrine, paracrine and autocrine factors, are extensively studied with the hope to interfere and to inhibit weight gain and related complications in obese patients. Recent data suggest an important role of bone morphogenic protein 4 (BMP4) in the regulation of adipogenesis and development of obesity. BMP4 is a growth factor of the transforming growth factor-ß superfamily. Initially, BMPs were identified as inducers of ectopic bone formation. It is now apparent, however, that these proteins have different pleiotropic developmental actions and including playing a role in white adipogenesis. METHODS AND RESULTS: Here, we demonstrate that the expression of BMP4 in human WAT is negatively correlated to body mass index and to the expression of pro-inflammatory cytokines. In vitro, BMP4 expression in cultured human adipocytes is upregulated after induction of differentiation. Cells treated with exogenous BMP4 increased peroxisome proliferator-activated receptor γ (PPARγ) expression and significantly reduced the expression of pro-inflammatory cytokines including tumor necrosis factor α (TNF-α) and monocyte chemoattractant protein 1. TNF-α treatment of fully differentiated adipocytes resulted in downregulation of the expression of adipogenic genes and elevated expression of pro-inflammatory cytokines. Exogenous BMP4 addition significantly reduced the negative effect of TNF-α on the expression profile of adipocytes. Finally, treatment of human adipocytes with exogenous BMP4 reduced the adipocytes' chemoattractant potential and the migration of monocytes toward adipocyte-conditioned medium. CONCLUSIONS: These results indicate that BMP4 is an important anti-inflammatory molecule, which may act through PPARγ and reduces TNF-α-mediated pro-inflammatory cytokine production in human adipocytes. Through its anti-inflammatory potential, BMP4 may serve as a protective factor for inflammation-related diseases such as insulin-tolerance or type-2 diabetes.

Enhancement of the sensitivity of a temperature sensor based on fiber Bragg gratings via weak value amplification.

We present a proof-of-concept experiment aimed at increasing the sensitivity of Fiber-Bragg-gratings temperature sensors by making use of a weak-value-amplification scheme. The technique requires only linear optics elements for its implementation and appears as a promising method for increasing the sensitivity than state-of the-art sensors can currently provide. The device implemented here is able to generate a shift of the centroid of the spectrum of a pulse of ∼0.035 nm/°C, a nearly fourfold increase in sensitivity over the same fiber-Bragg-grating system interrogated using standard methods.

Temperature gradient sensor based on a long-fiber Bragg grating and time-frequency analysis.

A photonic sensor based on a 10-cm-long fiber Bragg grating (FBG) is presented and experimentally validated that is dedicated to detect the presence and the position of a temperature gradient. The system is based on the measurement of the central frequency distribution of the grating based on time-frequency domain analysis. A short optical pulse, having duration much shorter than the transit time along the grating, is coupled into the FBG, and the back-reflected pulse is scanned by means of an oscilloscope. A spatial resolution of 1 mm, given by half the input pulse duration, is achieved. The proposed sensor is based on a simple configuration and presents a sensing range of 10 cm, which could be further enhanced by fabricating a longer grating.

Time resolved emission at 1.3 µm of a single InAs quantum dot by using a tunable fibre Bragg grating.

Photoluminescence and time resolved photoluminescence from single metamorphic InAs/GaAs quantum dots (QDs) emitting at 1.3 µm have been measured by means of a novel fibre-based characterization set-up. We demonstrate that the use of a wavelength tunable fibre Bragg grating filter increases the light collection efficiency by more than one order of magnitude as compared to a conventional grating monochromator. We identified single charged exciton and neutral biexciton transitions in the framework of a random population model. The QD recombination dynamics under pulsed excitation can be understood under the weak quantum confinement potential limit and the interaction between carriers at the wetting layer and QD states.

Tunable and reconfigurable multi-tap microwave photonic filter based on dynamic Brillouin gratings in fibers.

We propose and experimentally demonstrate new architectures to realize multi-tap microwave photonic filters, based on the generation of a single or multiple dynamic Brillouin gratings in polarization maintaining fibers. The spectral range and selectivity of the proposed periodic filters is extensively tunable, simply by reconfiguring the positions and the number of dynamic gratings along the fiber respectively. In this paper, we present a complete analysis of three different configurations comprising a microwave photonic filter implementation: a simple notch-type Mach-Zehnder approach with a single movable dynamic grating, a multi-tap performance based on multiple dynamic gratings and finally a stationary grating configuration based on the phase modulation of two counter-propagating optical waves by a common pseudo-random bit sequence (PRBS).

Ultracompact electro-optic phase modulator based on III-V-on-silicon microdisk resonator.

A novel ultracompact electro-optic phase modulator based on a single 9 µm-diameter III-V microdisk resonator heterogeneously integrated on and coupled to a nanophotonic waveguide is presented. Modulation is enabled by effective index modification through carrier injection. Proof-of-concept implementation involving binary phase shift keying modulation format is assembled. A power imbalance of ∼0.6 dB between both symbols and a modulation rate up to 1.8 Gbps are demonstrated without using any special driving technique.

Coinfection with hepatitis C virus, oxidative stress and antioxidant status in HIV-positive drug users in Miami.

BACKGROUND: The pathogenesis of HIV/hepatitis C virus (HCV) coinfection is poorly understood. We examined markers of oxidative stress, plasma antioxidants and liver disease in HIV/HCV-coinfected and HIV-monoinfected adults. METHODS: Demographics, medical history, and proof of infection with HIV, hepatitis A virus (HAV), hepatitis B virus (HBV) and HCV were obtained. HIV viral load, CD4 cell count, complete blood count (CBC), complete metabolic panel, lipid profile, and plasma concentrations of zinc, selenium, and vitamins A and E were determined. Malondialdehyde (MDA) and glutathione peroxidase concentrations were obtained as measures of oxidative stress. Aminotransferase to platelet ratio index (APRI) and fibrosis index (FIB-4) markers were calculated. RESULTS: Significant differences were found between HIV/HCV-coinfected and HIV-monoinfected participants in levels of alanine aminotransferase (ALT) (mean±standard deviation: 51.4±50.6 vs. 31.9±43.1 U/L, respectively; P=0.014), aspartate aminotransferase (AST) (56.2±40.9 vs. 34.4±30.2 U/L; P<0.001), APRI (0.52±0.37 vs. 0.255±0.145; P=0.0001), FIB-4 (1.64±.0.91 vs. 1.03±0.11; P=0.0015) and plasma albumin (3.74±0.65 vs. 3.94±0.52 g/dL; P=0.038). There were no significant differences in CD4 cell count, HIV viral load or antiretroviral therapy (ART) between groups. Mean MDA was significantly higher (1.897±0.835 vs. 1.344± 0.223 nmol/mL, respectively; P=0.006) and plasma antioxidant concentrations were significantly lower [vitamin A, 39.5 ± 14.1 vs. 52.4±16.2 µg/dL, respectively (P=0.0004); vitamin E, 8.29±2.1 vs. 9.89±4.5 µg/mL (P=0.043); zinc, 0.61±0.14 vs. 0.67±0.15 mg/L (P=0.016)] in the HIV/HCV-coinfected participants than in the HIV-monoinfected participants, and these differences remained significant after adjusting for age, gender, CD4 cell count, HIV viral load, injecting drug use and race. There were no significant differences in glutathione peroxidase concentration, selenium concentration, body mass index (BMI), alcohol use or tobacco use between groups. Glutathione peroxidase concentration significantly increased as liver disease advanced, as measured by APRI (ß=0.00118; P=0.0082) and FIB-4 (ß=0.0029; P=0.0177). Vitamin A concentration significantly decreased (ß=-0.00581; P=0.0417) as APRI increased. CONCLUSION: HIV/HCV coinfection is associated with increased oxidative stress and decreased plasma antioxidant concentrations compared with HIV monoinfection. Research is needed to determine whether antioxidant supplementation delays liver disease in HIV/HCV coinfection.

WDM compatible and electrically tunable SPE-OCDMA system based on the temporal self-imaging effect.

A coding/decoding setup for a spectral phase encoding optical code-division multiple access (SPE-OCDMA) system has been developed. The proposal is based on the temporal self-imaging effect and the use of an easily tunable electro-optic phase modulator to achieve line-by-line coding of the transmitted signal, thus assuring compatibility with WDM techniques. Modulation of the code is performed at the same rate as the data, avoiding the use of high-bandwidth electro-optic modulators. As proof of concept of the technique, experimental results are presented for a back-to-back coder/decoder setup transmitting a 10 GHz unmodulated optical pulse train within an 80 GHz optical window and using 8-chip Hadamard codes.

Cysteinyl leukotrienes mediate the enhancing effects of indomethacin and aspirin on eosinophil production in murine bone marrow cultures.

BACKGROUND: Prostaglandin E(2) (PGE(2)) suppresses, while indomethacin and aspirin enhance, eosinophil production in murine liquid bone-marrow cultures. Because cysteinyl leukotrienes (cys-LTs) enhance human eosinophil colony formation, we investigated whether the effects of indomethacin and aspirin on murine bone-marrow were due to blockade of PGE(2) production alone, or involved further promotion of cys-LTs production/signalling. EXPERIMENTAL APPROACH: BALB/c liquid bone-marrow cultures were established with IL-5, alone or associated with indomethacin, aspirin, or cys-LTs. The effects of preventing cys-LT production or signalling were assessed. KEY RESULTS: Indomethacin and aspirin counteracted the suppression of eosinophil production by exogenous PGE(2). LTD(4), LTC(4) and LTE(4) enhanced IL-5-dependent eosinophil production and further counteracted the effect of exogenous PGE(2). The 5-lipoxygenase activating protein (FLAP) inhibitor, MK886, a leukotriene synthesis inhibitor, zileuton, the CysLT(1) receptor antagonists, MK571 and montelukast, or inactivation of the LTC(4) synthase gene, abolished effects of indomethacin and aspirin. MK886 and zileuton were ineffective but MK571 and montelukast were effective, against LTD(4). Indomethacin, aspirin and LTD(4) failed to enhance eosinophil production in bone-marrow from CysLT1 receptor-deficient mice. Indomethacin, aspirin and LTD(4) no longer counteracted the effects of exogenous PGE(2) in the presence of MK571 and montelukast. MK886, MK571 and montelukast had no effect by themselves, or in association with PGE(2). CONCLUSIONS AND IMPLICATIONS: Dependence on the FLAP/5-lipoxygenase/LTC(4) synthase pathway and receptor signalling shows that cyclo-oxygenase inhibitors act here through endogenous cys-LTs. While PGE(2) does not act by suppressing cys-LT production, cys-LTs override PGE(2) signalling. Eosinophil production is therefore coordinately regulated by both pathways.

C-reactive protein: a poor marker of cardiovascular disease risk in HIV+ populations with a high prevalence of elevated serum transaminases.

Blood lipids and high-sensitivity C-reactive protein (hsCRP) are used to assess cardiovascular disease (CVD) risk. We evaluated in a cross-sectional design the relationship of hsCRP to markers of liver function (aspartate and alanine transaminases [AST and ALT, respectively]), CVD risk factors and HIV-disease progression markers in 226 HIV-1 sero-positive drug users. hsCRP showed a significant inverse relationship with ALT and high-density lipoprotein, independent of age, gender, viral load, CD4 cell-count and antiretroviral (ARV) use, and was not significantly associated with HIV-disease progression markers. Serum markers of liver damage, AST and ALT, were associated with lower hsCRP, total cholesterol, low-density lipoproteins and triglycerides. Elevated liver enzymes (> or =40 IU/L) were predictive of hsCRP levels that are considered a low risk for CVD. In conclusion, hsCRP may not be a reliable marker of CVD risk in populations with HIV at-risk for elevated liver enzymes due to high hepatitis B virus/hepatitis C virus prevalence and ARV use.

All-Optical flip-flop operation using a SOA and DFB laser diode optical feedback combination.

We report on the switching of an all-optical flip-flop consisting of a semiconductor optical amplifier (SOA) and a distributed feedback laser diode (DFB), bidirectionally coupled to each other. Both simulation and experimental results are presented. Switching times as low as 50ps, minimal required switch pulse energies below 1pJ and a repetition rate of 1.25GHz have been measured. Contrast ratios over 25dB have been obtained. The dependence on the pulse length and CW input power of the minimal required switch energy is investigated.

Reproductive cycle of Macrobrachium amazonicum females (Crustacea, Palaemonidae).

Macrobrachium amazonicum is considered a favorite Brazilian species of freshwater prawn for cultivation as a result of its quick development and because it is easy to maintain in captivity. The aim of this work is to describe the sexual cycle stages and determine maturation age of the female M. amazonicum, which was collected monthly from June, 2002 to May, 2003 in the Jaguaribe River, Itaiçaba, Ceará. A monthly sample of water was also collected to determine the following parameters: temperature, dissolved oxygen, pH and salinity. A monthly sample of females was selected among the individuals caught, to determine the total weight (W(T)), carapace length (L( C)) and abdomen+telson length (L(A+T)) and to register the number of non-ovigerous females (NOF) and ovigerous females (OF). Determining ovarian maturation stages of M. amazonicum was done in a laboratory by observing macroscopic characters such as coloring, size, location and appearance of ovarians examined by transparent carapace. The first maturation age was determined from the relative frequency of the total length (L(T)) of young and adult females. The environmental parameters of the Jaguaribe River did not hold any influence in the number of individuals collected. A total of 1,337 prawns were sampled, 513 males (38.4%) and 824 females (61.6%). The proportion between males and females in the studied population was of 1:1.6. Among the collected females, 492 (50.7%) did not carry eggs in their abdomens (NOF) and 332 (40.3%) carried eggs in their abdomens (OF). There was no record of intact females. Non-ovigerous females with mature ovaries were recorded throughout all the months of collection. The female ovaries were classified as immature (IM), rudimentary (RU), intermediary (IN) and mature (M). M. amazonicum females reach their first sexual maturity between 4.5 and 5.5 cm of total length.

All-Optical Fiber Hanbury Brown &Twiss Interferometer to study 1300 nm single photon emission of a metamorphic InAs Quantum Dot.

New optical fiber based spectroscopic tools open the possibility to develop more robust and efficient characterization experiments. Spectral filtering and light reflection have been used to produce compact and versatile fiber based optical cavities and sensors. Moreover, these technologies would be also suitable to study N-photon correlations, where high collection efficiency and frequency tunability is desirable. We demonstrated single photon emission of a single quantum dot emitting at 1300 nm, using a Fiber Bragg Grating for wavelength filtering and InGaAs Avalanche Photodiodes operated in Geiger mode for single photon detection. As we do not observe any significant fine structure splitting for the neutral exciton transition within our spectral resolution (46 µeV), metamorphic QD single photon emission studied with our all-fiber Hanbury Brown &Twiss interferometer could lead to a more efficient analysis of entangled photon sources at telecom wavelength. This all-optical fiber scheme opens the door to new first and second order interferometers to study photon indistinguishability, entangled photon and photon cross correlation in the more interesting telecom wavelengths.

Spectral characterization of differential group delay in uniform fiber Bragg gratings.

In this paper, we completely study the wavelength dependency of differential group delay (DGD) in uniform fiber Bragg gratings (FBG) exhibiting birefringence. An analytical expression of DGD is established. We analyze the impact of grating parameters (physical length, index modulation and apodization profile) on the wavelength dependency of DGD. Experimental results complete the paper. A very good agreement between theory and experience is reported.

Differences in the intracellular accumulation of HIV protease inhibitors in vitro and the effect of active transport.

OBJECTIVES: To investigate the intracellular accumulation of HIV protease inhibitors (PI) and to assess the effect of active transport on this accumulation. METHODS: CEM cells were incubated with a PI for 18 h and the intracellular concentration determined using cell number and radioactivity. The effect of active transport was investigated using cells expressing P-glycoprotein (CEM(VBL)) and cells expressing multidrug resistance-associated protein 1 (MRP1; CEM(E1000)). Incubations were also carried out at 4 degrees C and in the presence of 2-deoxyglucose plus rotenone to examine the effect of inhibiting active transport. RESULTS: Nelfinavir (NFV) accumulated to the greatest extent (> 80-fold) followed by saquinavir (SQV; approximately 30-fold), ritonavir (RTV; 3-7-fold) and finally indinavir (IDV; extracellular equivalent to intracellular). In CEM(VBL) cells there was a significant reduction in the intracellular accumulation of NFV, SQV and RTV and in CEM(E1000) cells there was reduced accumulation of SQV and RTV. Inhibition of active transport processes caused a reduction in SQV and RTV accumulation but had no effect on IDV accumulation in all cell types. NFV accumulation was increased in CEM(VBL) cells as a result of inhibition of active transport. CONCLUSIONS: Marked differences can be detected in the intracellular accumulation of HIV PI drugs in vitro. Both P-glycoprotein and MRP1 may play a role in limiting the intracellular concentration of the PI and active influx mechanisms may contribute to drug accumulation.

Lonidamine in malignant brain tumors.

Among new therapeutic modalities for both primary and secondary brain tumors, selective manipulation of metabolic pathways seems attractive. In human malignant gliomas and cell lines from a glioblastoma multiform, lonidamine has been shown to interfere with aerobic glycolysis with a decrease of lactate production by the inhibition of a mitochondrially-bound hexokinase; this selective reduction of the energetic capabilities of glioma cells would be a limiting factor for processes requiring energy, such as cell growth and recovery from potentially lethal damage after radiotherapy or chemotherapy. The activity of lonidamine in malignant gliomas after surgery in association with conventional radiotherapy is being investigated, while previous studies have suggested a limited, but clear therapeutic activity of the drug in recurrent malignant gliomas. In brain metastases lonidamine has not been effective as a radiation enhancer, but has been shown to potentiate systemic chemotherapy. Most common side effects were myalgias, testicular pain and ototoxicity with no serious organ toxicity or myelosuppression.

Conservation of the Plasmodium falciparum sporozoite surface protein gene, STARP, in field isolates and distinct species of Plasmodium.

The extent of structural conservation of the Plasmodium falciparum sporozoite surface protein gene, STARP, recently characterized in the T9/96 clone, has been analyzed using the polymerase chain reaction. Results from Ivory Coast and Thai clones, field isolates originating from Brazil and Kenya and laboratory-maintained strains strongly suggest that this gene has a highly conserved structure throughout this species. This structure includes a complex repetitive central domain consisting of a mosaic region followed by tandem 45-amino acid-encoding (Rp45) and 10-amino acid-encoding (Rp10) repeat regions. Limited size variation in this domain appeared to result from highly localized duplication events in the Rp45 and Rp10 regions. No size variation was observed in the 5' and 3' coding non-repetitive regions, but minor size polymorphism was found in the single intron at the 5' end of the gene. No evidence was found of distinct families of polymorphic types, as has been observed with the blood-stage MSA-1, MSA-2 and S-antigens. The sequence of the STARP homologue in the phylogenetically close chimpanzee parasite, Plasmodium reichenowi, has also been elucidated and reveals high sequence conservation, although interesting differences were detected in the composition of the Rp10 region, known in P. falciparum to contain B- and T-cell epitopes. Finally, DNA hybridization reveals the presence in rodent malaria species of sequences containing homology to the STARP non-repetitive (though not the repetitive) regions, which would suggest that a similar, conserved gene may exist in these species.

Effect of ribavirin on zidovudine efficacy and toxicity in vitro: a concentration-dependent interaction.

Zidovudine (ZDV) is converted to its active triphosphate (ZDVTP) by intracellular kinases. The intermediate ZDV monophosphate (ZDVMP) is believed to play a major role in ZDV toxicity. Manipulation of ZDV phosphorylation is a possible therapeutic strategy for altering the risk-benefit ratio. Here we investigate whether combining RBV with ZDV is able to modulate efficacy and toxicity of ZDV. We have measured the intracellular activation of ZDV (0.3 microM) in the absence and presence of ribavirin (RBV; 2 and 20 microM) in Molt 4 and U937 cells. MTT cytotoxicity of ZDV (10-1000 microM) was also measured with and without RBV (2 microM) in Molt 4 and U937 cells. Measurement of endogenous deoxythymidine triphosphate (dTTP) allowed investigation of the dTTP/ZDVTP ratio. The antiviral efficacy of ZDV in combination with RBV (2 microM) was assessed by HIV p24 antigen measurements. In the presence of RBV (2 and 20 microM) a decrease in total ZDV phosphates was observed, owing mainly to an effect primarily on ZDVMP rather than the active ZDVTP. RBV also increased endogenous dTTP pools in both cell types, resulting in an increase in the dTTP/ZDVTP ratio. ZDV alone significantly reduced p24 antigen production, with an IC50 of 0.34 microM. Addition of RBV increased the IC50 approximately fivefold (1.52 microM). However, at higher concentrations of ZDV (10 and 100 microM) the antagonistic effect of RBV (2 microM) on ZDV was lost. The RBV-mediated decrease in ZDVMP may explain the reduction in ZDV toxicity when combined with RBV (2 microM). Cytotoxicity of ZDV was reduced in the presence of RBV (2 microM) at all concentrations in both cell lines, probably owing to saturation of ZDVTP formation. The interaction of ZDV and RBV is concentration dependent.

Intracellular activation of 2',3'-dideoxyinosine and drug interactions in vitro.

Didanosine (2',3'-dideoxyinosine; ddI) requires intracellular metabolism to its active triphosphate, 2',3'-dideoxyadenosine 5'-triphosphate (ddATP), to inhibit the replication of human immunodeficiency virus (HIV). We have investigated the metabolism of ddI to ddATP in the presence and absence of a range of compounds. In addition, we determined the levels of the endogenous competitor of ddATP, 2'-deoxyadenosine 5'-triphosphate (dATP), and calculated ddATP/dATP ratios. None of the nucleoside analogs studied had any effect on ddI phosphorylation at 1 and 10 microM concentrations. At 100 microM concentrations, ddC reduced total ddA phosphates (82% of control total ddA phosphates; p < 0.001). ZDV significantly decreased the levels of dATP, whereas ddC significantly increased dATP pools (e.g., at 100 microM ZDV, 82% of control dATP levels; p < 0.001). Hence, the ddATP/dATP ratio was increased in the presence of ZDV, but was decreased in the presence of ddC. Neither d4T nor 3TC affected the ddATP/dATP ratio. Deoxyinosine (dI) significantly reduced ddA phosphate production at 100 microM concentrations, with ddATP reduced to undetectable levels (p < 0.001). Hydroxyurea (HU) did not affect the activation of ddI, but significantly reduced dATP pools at 100 microM concentrations (67% of control dATP levels; p < 0.001), enhancing the ddATP/dATP ratio. ddA phosphate production was significantly reduced by pentoxyfylline (PXF) at 10 and 100 microM concentrations. dATP levels were unaffected, but the ddATP/dATP ratio was reduced. Finally, 8-aminoguanosine (8-AMG) had no effect on either ddI activation or dATP pools. These studies demonstrate the importance of determining both the active TP and the competing endogenous TP, as changes to the resulting ratio could alter the efficacy of the nucleoside analog in question.

Automatic tunable and reconfigurable fiberoptic microwave filters based on a broadband optical source sliced by uniform fiber Bragg gratings.

We demonstrate an automatic tunable transversal notch filter based on uniform fiber Bragg gratings and a broadband optical source. High tunability can be performed by stretching the fiber with the gratings written in series. Also, high sidelobe supression can be achieved by introducing tunable attenuators in a parallel configuration of the gratings.