PC Concentration Research Articles

Evaluation of remote sensing algorithms for cyanobacterial pigment retrievals during spring bloom formation in several lakes of East China

Using reflectance data and water sample data from 75 stations in several eutrophic lakes of East China (Lake Taihu, Lake Gehu, Lake Dongjiu) between 23 April and 3 May 2010, we evaluated several recently proposed remote sensing algorithms to estimate chlorophyll-a concentrations (Chla, 1.0–42μg/L) and phycocyanin pigment concentrations (PC, 0.1–7.7μg/L). These lakes experience phytoplankton blooms of the cyanobacteria Microcystis aeruginosa every year due to eutrophication. It was found that after local tuning of the algorithm parameterizations, most algorithms yielded acceptable results for Chla retrievals while accurate PC retrievals were more challenging due to changing species composition (PC:Chla ratios) and low PC concentrations. For the data ranges in the study region, the best Chla algorithm yielded RMSErel (Relative Root Mean Square Error) of ~46% (R2=0.92, n=75) and the best PC algorithm yielded RMSErel of ~83% (R2=0.88, n=75). Based on these observations, it is recommended that local tuning of algorithm parameters should be performed for remote sensing applications, and future efforts should emphasize on application of the algorithms to satellite data.

P-cresol, but not p-cresylsulphate, disrupts endothelial progenitor cell function in vitro

Patients afflicted with chronic kidney disease (CKD) typically suffer from cardiovascular disease (CVD) which is a leading cause of patient mortality. It has been demonstrated that two distinct physiological events contribute to this disease state. These include the abundance of abnormally high levels of protein-bound uraemic toxins as well as functionally aberrant endothelial progenitor cells (EPCs). Specifically, it has been demonstrated that the uraemic toxin p-cresol (pC; 4-methylphenol) inhibits EPC proliferation and tube formation in previous in vitro studies. More recently, however, it has been demonstrated that circulating pC is actually conjugated and that p-cresylsulphate (pCS) is its main metabolite. Therefore, within the context of this study, we examined the in vitro effects of pC and pCS treatment on cultured human EPCs. Late-outgrowth EPCs were treated with physiological concentrations of pC or pCS (10, 40, 80, and 160 or 10, 40, 80, 160 and 320 µg/mL for up to 72 h, respectively) in the presence of 4% human serum albumin (HSA). Cell proliferation was determined using WST-1 assay, while migration and tube formation assays were used to evaluate EPC function in vitro. Cell cycle analyses were also performed to determine the effects of pC and pCS on cell cycle status. With regard to EPC proliferation, data demonstrate that pC in the presence or absence of HSA had an IC50 of 80.1 and 100.8 µg/mL 72 h post-treatment, respectively, while pCS-treated groups did not impair EPC proliferation. Similarly, pC-treated groups showed limited vessel formation and migration compared with controls and no detrimental effects were seen with pCS treatment. Lastly, pC treatment of EPCs caused cells to accumulate in the G2/M phase of the cell cycle with accompanied down-regulation of cyclin B1 and phosphorylated CDK1. pCS had no effect on cell cycle parameters. Our data demonstrate that pC and pCS have different effects on EPC function. Since there is a dearth of data that have focused on the toxicity of pCS, further research should be performed to determine the exact biological toxicity of pCS on the cardiovascular system.

Quantitative determination of phosphatidylcholine hydroperoxides during copper oxidation of LDL and HDL by liquid chromatography/mass spectrometry

1-Palmitoyl-2-linoleoylphosphatidylcholine monohydroperoxide (PC 16:0/18:2-OOH) and 1-stearoyl-2-linoleoylphosphatidylcholine monohydroperoxide (PC 18:0/18:2-OOH) were measured by liquid chromatography/mass spectrometry (LC/MS) using nonendogenous 1-palmitoyl-2-heptadecenoylphosphatidylcholine monohydroperoxide as an internal standard. The calibration curves for synthetic PC 16:0/18:2-OOH and PC 18:0/18:2-OOH, which were obtained by direct injection of the internal standard into the LC/MS system, were linear throughout the calibration range (0.8-12.8 pmol). Within-day and between-day coefficients of variation were less than 10%, and the recoveries were between 86% and 105%. The limit of detection (LOD) and the limit of quantification (LOQ) were determined using synthetic standards. The LOD (signal-to-noise ratio 3:1) was 0.01 pmol, and the LOQ (signal-to-noise ratio 6:1) was 0.08 pmol for both PC 16:0/18:2-OOH and PC 18:0/18:2-OOH. With use of this method, the concentrations of PC 16:0/18:2-OOH and PC 18:0/18:2-OOH in the lipoprotein fractions during copper-mediated oxidation were determined. We prepared oxLDL and oxHDL by incubating native LDL and native HDL from human plasma (n = 10) with CuSO(4) for up to 4 h. The time course of the PC 16:0/18:2-OOH and PC 18:0/18:2-OOH levels during oxidation consisted of three phases. For oxidized LDL, both compounds exhibited a slow lag phase and a subsequent rapidly increasing propagation phase, followed by a gradually decreasing degradation phase. In contrast, for oxidized HDL, both compounds initially exhibited a prompt propagation phase with a subsequent plateau phase, followed by a rapid degradation phase. The analytical LC/MS method for phosphatidylcholine hydroperoxides might be useful for the analysis of biological samples.

Protein carbonyl groups in trained subjects

The purpose of this research was to evaluate the plasma protein carbonyl groups (PC) in 81 trained subjects (TS) who practiced regular, non professional physical activity. They were divided into three groups according to the type of sport they practiced (endurance, mixed or power). On fasting venous blood we examined the PC groups employing an enzyme-linked immunosorbent assay (ELISA) kit, in which 2,4-dinitrophenyl-hydrazine reacts with the PC forming a stable hydrazone product. In the whole group of TS a significant decrease in PC was present, in comparison with sedentary controls (SC). Dividing TS into groups, we observed a decreased PC concentration in those practicing endurance and mixed sports, but not in those practicing power sports. There was no difference between men and women for PC either in SC or in TS; male TS had a PC concentration significantly lower than male SC. Our data show that body proteins are more protected against oxidative stress in subjects who practice endurance and mixed sports. These results give further support to the promotion of regular physical activity including aerobic exercise.

The Effect of Cause of Cadaveric Kidney Donors Death on Fibrinolysis and Blood Coagulation Processes

Background Organ donors can be generally divided into two groups according to the cause of their death. The first group is composed of those who died because of physical injuries, especially road traffic injury, and the second group, those who died from central nervous system (CNS) stroke or bleeding. The aim of our work was to examine hemostatic processes among kidney donors. Materials and methods The 38 deceased kidney donors (KD) included 11 women and 27 men of overall average age of 37 ± 12 years. The donor group of according to the cause of death, included 14 injured donors (ID) (41%) and 24 noninjured donors (ND) donors (59%). The control group consisted of 25 healthy volunteers matched for sex and age. We determined the following concentrations: antithrombin (AT), thrombin/antithrombin complexes (TAT), and prothrombin F1 + 2 fragments. The fibrinolytic parameter concentrations were: plasminogen (PL), plasmin/antiplasmin complexes (PAP), and D-dimers. Results Deceased kidney donors showed an increased plasma concentrations of TAT complexes ( P < .000001) and prothrombin fragments F1 + 2 ( P < .0000001); however, the protein C concentration was decreased ( P < .000001). The antithrombin activity was similar to the control group. The concentrations of PAP complexes and d-dimers were higher (both P < .000001), but the level of PL lower among KD compared with controls ( P < .0000001). The higher of TAT, PAP complexes, d-dimers, and F1 + 2 concentrations as well and as lower plasminogen and PC concentrations were evidence for increased activation of blood coagulation and fibrinolysis in cadaveric KD. However, analysis compairing ID versus ND donors revealed increased concentrations of PAP complexes ( P < .05) and decreased amounts of TAT complexes ( P < .01) among ID subgroup. The positive predictive value (PPV) and negative (NPV) for PAP complexes were 75% and 68% and for TAT, 71% and 57%, respectively. On the basis of these observations, we concluded that an intensive activation of fibrinolytic process occurs among the ID. In contrast, ND show intensive activation of blood coagulation.

Induction of metal binding compounds and antioxidative defence in callus cultures of two black poplar (P. nigra) clones with different tolerance to cadmium

Callus cultures of two parental clones of Populus nigra L., Poli and 58-861, originating from contrasting environments, were exposed to different cadmium concentrations (0, 150 and 250 μM CdSO4). Clones showed different growth responses to cadmium, evaluated by the tolerance index (Ti), with Poli being more tolerant to the metal at both concentrations. The cadmium concentration at the end of the treatment was very similar between clones at 150 μM CdSO4, while a higher value in 58-861 compared to Poli was detected at 250 μM CdSO4. The bioconcentration factor evidenced the lowest value in Poli at 250 μM CdSO4. Unlike 58-861, cadmium provoked a strong induction of thiols and phytochelatins in clone Poli. In both clones, organic acid concentration differed notably in untreated calli and cadmium treatment induced a general lowering of these compounds. A notably higher antioxidant enzyme activity (ascorbate peroxidase, APX; catalase, CAT; guaiacol peroxidase, GPX) was measured in control calli of clone Poli compared to 58-861. Cadmium induced a remarkable enhancement of APX and CAT, but not GPX, activity at 150 μM CdSO4 in Poli. Conversely, in 58-861 at 150 μM CdSO4, and in both clones at 250 μM CdSO4, a decrease in the antioxidant activity occurred. This investigation provided evidence that these two contrasting genotypes of P. nigra are characterised by a different response to cadmium in callus cultures. In particular, in Poli, the higher tolerance to cadmium is associated with a higher activity of antioxidative enzymes and the ability to strongly increase thiol and PC concentration in response to metal exposure.

Influence of hot-air temperature on drying kinetics, functional properties, colour, phycobiliproteins, antioxidant capacity, texture and agar yield of alga Gracilaria chilensis

Effect of air temperature on drying kinetics, functional properties, phycobiliproteins (PE and PC), colour, antioxidant capacity, total phenolic content, texture and agar yield during drying of algae Gracilaria chilensis were studied. Drying curves were satisfactorily simulated with the Weibull model at 40, 50, 60 and 70 °C. Both, Rehydration Ratio and Water Holding Capacity decreased with increasing temperature. Low drying temperatures showed higher PE and PC concentration than higher temperatures (e.g. 60 and 70 °C). In particular, dehydration at 50 °C presented the higher values of these two pigments. The three chromatic coordinates (L∗, a∗ and b∗) were influenced by the treatments showing the highest ∆E value at 50 °C. Antioxidant activity as well as texture were notably influenced by increasing drying temperatures. At 70 °C, a maximum agar yield of 40 g/100 g was obtained. Results indicated that agar yield and quality of dried algae showed opposite behaviours leading to a compromise decision on operating conditions involved in the overall process. According to these results, optimization of the process based on economical aspects of the final dried product is required.

Ischemic post-conditioning attenuates the intestinal injury induced by limb ischemia/reperfusion in rats

The purpose of this study was to investigate the protective effects of ischemic post-conditioning on damage to the barrier function of the small intestine caused by limb ischemia-reperfusion injury. Male Wistar rats were randomly divided into 3 groups (N = 36 each): sham operated (group S), lower limb ischemia-reperfusion (group LIR), and post-conditioning (group PC). Each group was divided into subgroups (N = 6) according to reperfusion time: immediate (0 h; T1), 1 h (T2), 3 h (T3), 6 h (T4), 12 h (T5), and 24 h (T6). In the PC group, 3 cycles of reperfusion followed by ischemia (each lasting 30 s) were applied immediately. At all reperfusion times (T1-T6), diamine oxidase (DAO), superoxide dismutase (SOD), and myeloperoxidase (MPO) activity, malondialdehyde (MDA) intestinal tissue concentrations, plasma endotoxin concentrations, and serum DAO, tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10) concentrations were measured in sacrificed rats. Chiu's pathology scores for small intestinal mucosa were determined under a light microscope and showed that damage to the small intestinal mucosa was lower in group PC than in group LIR. In group PC, tissue DAO and SOD concentrations at T2 to T6, and IL-10 concentrations at T2 to T5 were higher than in group LIR (P < 0.05); however, tissue MPO and MDA concentrations, and serum DAO and plasma endotoxin concentrations at T2 to T6, as well as TNF-α at T2 and T4 decreased significantly (P < 0.05). These results show that ischemic post-conditioning attenuated the permeability of the small intestines after limb ischemia-reperfusion injury. The protective mechanism of ischemic post-conditioning may be related to inhibition of oxygen free radicals and inflammatory cytokines that cause organ damage.

Ischemic post-conditioning attenuates the intestinal injury induced by limb ischemia/reperfusion in rats

The purpose of this study was to investigate the protective effects of ischemic post-conditioning on damage to the barrier function of the small intestine caused by limb ischemia-reperfusion injury. Male Wistar rats were randomly divided into 3 groups (N = 36 each): sham operated (group S), lower limb ischemia-reperfusion (group LIR), and post-conditioning (group PC). Each group was divided into subgroups (N = 6) according to reperfusion time: immediate (0 h; T1), 1 h (T2), 3 h (T3), 6 h (T4), 12 h (T5), and 24 h (T6). In the PC group, 3 cycles of reperfusion followed by ischemia (each lasting 30 s) were applied immediately. At all reperfusion times (T1-T6), diamine oxidase (DAO), superoxide dismutase (SOD), and myeloperoxidase (MPO) activity, malondialdehyde (MDA) intestinal tissue concentrations, plasma endotoxin concentrations, and serum DAO, tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10) concentrations were measured in sacrificed rats. Chiu’s pathology scores for small intestinal mucosa were determined under a light microscope and showed that damage to the small intestinal mucosa was lower in group PC than in group LIR. In group PC, tissue DAO and SOD concentrations at T2 to T6, and IL-10 concentrations at T2 to T5 were higher than in group LIR (P < 0.05); however, tissue MPO and MDA concentrations, and serum DAO and plasma endotoxin concentrations at T2 to T6, as well as TNF-α at T2 and T4 decreased significantly (P < 0.05). These results show that ischemic post-conditioning attenuated the permeability of the small intestines after limb ischemia-reperfusion injury. The protective mechanism of ischemic post-conditioning may be related to inhibition of oxygen free radicals and inflammatory cytokines that cause organ damage.

Tubular or Subsurface Morphology of Octabutoxyphthalocyanine upon Self‐Assembly in Polymer Matrices: Effect of the Casting Solvent

Spontaneous phase-separated, controlled aggregate structures of photo- and electroactive molecules in polymer matrices are of interest for device fabrication. We show that the self-assembly of octabutoxyphthalocyanine (Pc) in polymer matrices leads to tubular morphology of Pc when the film is prepared with tetrachloroethane (TCE) and subsurface droplet morphology with chloroform. The same morphology is seen with both bisphenol A polycarbonate (BPAPC) and poly(methyl methacrylate) (PMMA) as the matrix. The subsurface morphology results from the rapid association of Pc in the polymer matrix, as the film forms. With the tubular morphology in the films prepared with TCE, percolation threshold is reached with a concentration of Pc as low as 3% (wt) in the polymer. Such phase-separated self-assembly occurs, without any annealing of the films. Even in the absence of the polymer, Pc crystallized from TCE also shows tubular morphology, whereas it exhibits a columnar morphology with chloroform. X-ray diffraction of Pc crystallized from either solvent shows the columnar stacking of the Pc molecules. However, the morphology is tubular when TCE is used. We attribute the difference in the morphology to the higher viscosity of TCE and the diffusion-limited growth, which causes the tubular morphology, whereas the instantaneous self-assembly in less-viscous chloroform leads to droplets. The solvent effect observed here could be used to tailor the morphology of such photoconductive molecules in polymer matrices.

Abstract 1685: Nano-scale targeting of Pc 4 to improve drug delivery, accumulation, and PDT efficacy in brain tumors

Abstract Malignant gliomas are among the most lethal cancers with a median survival expectancy of only 6-12 months. Surgical resection is the mainstay of treatment. However, curative resection is often not possible due to infiltrating growth of the tumor into normal brain. Photodynamic therapy (PDT) has been suggested as an additional therapy to guide tumor resections and enhance the effect of surgery via photoreactive treatment during or at the cessation of surgical intervention. The most difficult challenge in treating malignant brain tumors may be delivering targeted therapies that preserve healthy tissue while effectively eradicating the cancer. Therefore, improving drug delivery rate and tumor selectivity of the photosensitizing agent will dramatically reduce systemic toxicity and enhance the success of PDT. EGFR amplification is the most common genetic alteration in gliomas and plays a critical role in stimulating glioma progression, making it an ideal target. Consequently, we have developed a highly efficient EGFR-targeted gold-nanoparticle (EGF-Au NP) to improve delivery of PDT cancer drugs to tumors in vivo. EGF peptides attached to PEGylated Au NPs deliver hydrophobic PDT drug, Pc 4, to brain tumors overexpressing EGFR better than either the non-targeted Au NPs or Pc 4 alone. The drug rapidly releases and penetrates deep within tumors within 1-4 hrs. In vivo small animal imaging experiments show targeted delivery of Pc 4 to tumor sites. Ex vivo imaging of the tumors confirmed as much as a 4-fold increase in the intrinsic fluorescence of Pc 4 over non-targeted conjugates after systemic administration. Moreover, in vitro experiments show a higher concentration of Pc 4 uptake per Au NP over non-targeted Au NPs per cancer cell. Histological analysis, including confocal microscopy, shows that, after targeting, the delivered Pc 4 localizes in the endosomes of the cancer cells. Transmission electron micrographs show that Au NPs cluster along the cell surface or within discrete vesicles within the cell. Localization within the endosomal pathway may be more effective for PDT and produce less off-target toxicity than free Pc 4, which preferentially accumulates in mitochondria. Further, glioma cells treated for 4 hrs with EGF-targeted Au NP-Pc 4 and then exposed to PDT show an enhanced killing effect, especially when compared to either non-targeted Au NP-Pc 4 or free Pc 4 controls. Systemic delivery of EGF-Au NP-Pc 4 to heterotopic brain tumors reveals increasing tumor necrosis after PDT. Biodistribution experiments also show that the Au NPs and Pc 4 are effectively excreted over time. This study suggests that the EGFR-targeted Au NPs improve drug delivery to tumors for PDT and are removed from the body safely after treatment. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1685. doi:10.1158/1538-7445.AM2011-1685

Accumulation and translocation of Cd metal and the Cd-induced production of glutathione and phytochelatins in Vicia faba L.

Translocation of cadmium (Cd) in the tissues of Vicia faba, the water content in biomass, the biomass production, and the glutathione and phytochelatin tissue concentrations were studied and correlated with the plant sensitivity and/or tolerance to Cd. The total concentrations of Cd were determined by inductively coupled plasma/mass spectrometry (ICP-MS), the concentrations of glutathione (GSH) and phytochelatins 2 and 3 (PC2 and PC3) were determined by on-line high performance liquid chromatography/electrospray-ionization tandem mass spectrometry (HPLC–ESI–MS–MS) in the roots and leaves of the sensitive and the tolerant cultivars of V. faba grown in Cd containing nutrient solutions (NS, 0–100 μmol l−1 Cd2+). Both the cultivars of V. faba accumulate a major portion of Cd in the roots and only a minor part of ca. 4% in the leaves. The differences between the cultivars concerning Cd accumulation in leaves were apparent from higher Cd concentrations in NS and the Cd amount in the sensitive cultivar was approximately twice as high. In the roots, the differences between the cultivars in the Cd accumulation were only statistically significant with the highest Cd concentrations in NS, with the tolerant cultivar accumulating about 16% more of Cd compared to the sensitive one. The biomass production of the sensitive cultivar decreased approximately twice as fast with increasing Cd concentration in NS. The biomass water content decreased with increasing Cd concentration in NS in both the cultivars. In general, the GSH concentration did not linearly correlate with Cd accumulation, except for the roots of the sensitive cultivar where it was independent, and was higher in the sensitive cultivar than in the tolerant one in both the leaves and roots. The GSH concentration in leaves was approximately one order of magnitude higher than that in the roots for both the cultivars. The relationships between the PC and Cd concentrations in tissues were found nonlinear. At lower Cd accumulation levels, the PC concentrations followed an increase in the Cd accumulation in both the roots and leaves, whereas at higher Cd accumulations the relations differed between roots and leaves. In the roots, the PC concentrations decreased with increasing Cd accumulation, whereas the PC concentration in the leaves followed the decrease in the Cd accumulation.

The involvement of oxidative stress in the mechanisms of damaging cadmium action in bone tissue: A study in a rat model of moderate and relatively high human exposure

It was investigated whether cadmium (Cd) may induce oxidative stress in the bone tissue in vivo and in this way contribute to skeleton damage. Total antioxidative status (TAS), antioxidative enzymes (glutathione peroxidase, superoxide dismutase, catalase), total oxidative status (TOS), hydrogen peroxide (H2O2), lipid peroxides (LPO), total thiol groups (TSH) and protein carbonyl groups (PC) as well as Cd in the bone tissue at the distal femoral epiphysis and femoral diaphysis of the male rats that received drinking water containing 0, 5, or 50mg Cd/l for 6months were measured. Cd, depending on the level of exposure and bone location, decreased the bone antioxidative capacity and enhanced its oxidative status resulting in oxidative stress and oxidative protein and/or lipid modification. The treatment with 5 and 50mg Cd/l decreased TAS and activities of antioxidative enzymes as well as increased TOS and concentrations of H2O2 and PC at the distal femur. Moreover, at the higher exposure, the concentration of LPO increased and that of TSH decreased. The Cd-induced changes in the oxidative/antioxidative balance of the femoral diaphysis, abundant in cortical bone, were less advanced than at the distal femur, where trabecular bone predominates. The results provide evidence that, even moderate, exposure to Cd induces oxidative stress and oxidative modifications in the bone tissue. Numerous correlations noted between the indices of oxidative/antioxidative bone status, and Cd accumulation in the bone tissue as well as indices of bone turnover and bone mineral status, recently reported by us (Toxicology 2007, 237, 89–103) in these rats, allow for the hypothesis that oxidative stress is involved in the mechanisms of damaging Cd action in the skeleton. The paper is the first report from an in vivo study indicating that Cd may affect bone tissue through disorders in its oxidative/antioxidative balance resulting in oxidative stress.

Steady and dynamic oscillatory shear rheological properties of ketchup–processed cheese mixtures: Effect of temperature and concentration

The steady and dynamic shear properties of ketchup–processed cheese (K–PC) mixtures were investigated at different temperatures (10–50 °C) and PC concentrations (0–30%). The K–PC mixtures showed a shear-thinning behavior with low magnitudes of yield stress. The consistency coefficient ( K) and apparent viscosity ( η 50) decreased with increase in temperature and concentration. The mixtures followed the Arrhenius temperature relationship, indicating that the magnitudes of activation energies ( E a ) were in the range of 8.83–17.16 kJ mol −1. Storage ( G′), loss ( G′′) and complex ( G∗) modulus increased with increase in frequency while complex viscosity ( η∗) decreased. The K–PC mixtures at concentrations of 0–15% exhibited weak gel-like behavior. Increase in the PC concentration resulted in a decrease in G∗, G′, G′′ and η∗ up to the 15% of PC concentration, showing a plateau value between 0% and 30% concentrations. Cox–Merz rule was not applicable to K–PC mixtures.

A comparative study of the protein C system in mother's blood, cord blood and amniotic fluid.

Activated protein C (APC) is an important anticoagulant which plays a role in pathophysiology of pregnancy, e.g. in maintenance of the uteroplacental circulation and development of the fetus as well as in pathogenesis of preeclampsia. The study objective was to compare the levels of the respective components of the protein C system (protein C, PC; protein S, PS; thrombomodulin, TM) as well as thrombin activatable fibrinolysis inhibitor - TAFI in mother's blood, cord blood and amniotic fluid. The study group consisted of 136 healthy parturients at term, divided into subgroups of 30-35. The immunoenzymatic method (ELISA) was used to measure the antigens of the components studied. The concentrations of PC and PS antigens were the highest in the mother's blood plasma (135.11+/-1.05% and 92.0+/-13.24%, respectively), lower in cord blood plasma (57.60+/-10.32% and 33.19+/-4.96%, respectively) and the lowest in amniotic fluid (6.75+/-3.50% and 2.40+/-1.64%, respectively); the differences between the levels of that of mother, fetus and amniotic fluid were statistically significant (p< or =0.0001). The TM and TAFI antigen concentrations were the highest in cord blood plasma (11.35+/-3.71 ng/ml and 91.50 (median; range: 71.76-160.77) ng/ml, respectively) and lower in maternal plasma (4.51+/-0.71 ng/ml and 55.46 - median; range: 39.77-68.54 ng/ml, respectively); the differences between the levels of that of cord blood plasma and maternal plasma were statistically significant (p< or =0.0001). Of the three protein C system components, PC and PS occur in relatively high concentrations in maternal blood, being lower in fetal blood and the lowest in amniotic fluid. On the other hand, as an exception, the concentrations of TM and TAFI are the highest in fetus blood.

Antioxidant therapy attenuates oxidative stress in the blood of subjects exposed to occupational airborne contamination from coal mining extraction and incineration of hospital residues

Coal mining and incineration of solid residues of health services (SRHS) generate several contaminants that are delivered into the environment, such as heavy metals and dioxins. These xenobiotics can lead to oxidative stress overgeneration in organisms and cause different kinds of pathologies, including cancer. In the present study the concentrations of heavy metals such as lead, copper, iron, manganese and zinc in the urine, as well as several enzymatic and non-enzymatic biomarkers of oxidative stress in the blood (contents of lipoperoxidation = TBARS, protein carbonyls = PC, protein thiols = PT, α-tocopherol = AT, reduced glutathione = GSH, and the activities of glutathione S-transferase = GST, glutathione reductase = GR, glutathione peroxidase = GPx, catalase = CAT and superoxide dismutase = SOD), in the blood of six different groups (n = 20 each) of subjects exposed to airborne contamination related to coal mining as well as incineration of solid residues of health services (SRHS) after vitamin E (800 mg/day) and vitamin C (500 mg/day) supplementation during 6 months, which were compared to the situation before the antioxidant intervention (Ávila et al., Ecotoxicology 18:1150-1157, 2009; Possamai et al., Ecotoxicology 18:1158-1164, 2009). Except for the decreased manganese contents, heavy metal concentrations were elevated in all groups exposed to both sources of airborne contamination when compared to controls. TBARS and PC concentrations, which were elevated before the antioxidant intervention decreased after the antioxidant supplementation. Similarly, the contents of PC, AT and GSH, which were decreased before the antioxidant intervention, reached values near those found in controls, GPx activity was reestablished in underground miners, and SOD, CAT and GST activities were reestablished in all groups. The results showed that the oxidative stress condition detected previously to the antioxidant supplementation in both directly and indirectly subjects exposed to the airborne contamination from coal dusts and SRHS incineration, was attenuated after the antioxidant intervention.

Total Choline at 1H-MRS and [18F]-Fluoromethylcholine Uptake at PET

The use of in vivo imaging techniques for assessing choline metabolism to detect cancer is supported by studies showing increased choline kinase and transporter gene expression, transmembrane choline transport, and tissue choline metabolite concentration in a number of malignancies [1, 2]. Early clinical studies employing techniques for in vivo imaging of choline metabolism looked promising, with early PET studies demonstrating increased choline tracer uptake in a variety of tumors, and independently, studies employing proton magnetic resonance spectroscopy (1H-MRS) demonstrating increased tissue levels of choline metabolites in several malignancies [2–5]. However, the use of these two very different in vivo methods to study choline metabolism have raised questions as to how their measurements interrelate; and there have been instances where choline tracer uptake on PET fails to correlate well with the tissue measurements of choline provided by 1H-MRS [6]. To address these questions, Rommel et al., in their study titled “Rodent Rhabdomyosarcoma: Comparison Between Total Choline Concentration at 1H-MRS and [F]-fluoromethylcholine (FCH) Uptake at PET Using Accurate Methods for Collecting Data”, employed methods for achieving highly accurate spatial correspondence between small-animal PET and MRI to study the relationship between FCH uptake and spectroscopic measurement of tissue choline metabolites in a rhabdomyosarcoma animal model. Their study did not confirm a quantitative relationship between tumor FCH uptake and measures of choline concentration obtained with 1H-MRS in their experimental model. The authors offered several biological hypotheses to explain the lack of correlation between FCH uptake and choline metabolite concentration: one involving the presence of a negative feed-back mechanism of elevated levels of intracellular choline compounds on FCH uptake; another involving the rapid transport and incorporation of choline into membrane phosphatidylcholine (which is not detectable by 1H-MRS) to explain increases in FCH uptake without corresponding increases in total choline metabolite concentration on 1H-MRS. In addition to these biological hypotheses, the limited ability of in vivo 1H-MRS to discriminate specific choline metabolites may also be worth considering as a potential explanation for their observations. Specifically, the “choline peak” at 3.2 ppm that is often used for in vivo 1H-MRS studies is known to actually reflect a number of important choline metabolites [7]. Ex vivo and in vitro NMR can readily differentiate several of these metabolites bearing the choline moiety. They include free choline, phosphocholine (PC; at 3.23 ppm), and glycerophosphocholine (GPC; at 3.24 ppm) [8, 9]. However, due to their spectral proximity it has proven difficult to resolve these compounds in vivo [2]. PC is a predominant biosynthetic product whose concentrations in malignancy can increase as a result of choline kinase upregulation [1]. GPC, on the other hand, is primarily a product of phospholipase activation [10, 11]. In the study by Rommel et al., the inability to separate the spectral contributions of these biochemically distinct compounds should raise the question of whether FCH uptake is actually being compared to the net result of several anabolic and catabolic processes in the CDP-choline pathway. Such a situation could potentially explain the lack of correlation observed between total choline concentration and FCH uptake. Work by DeGrado et al. has suggested FCH to be a marker of biosynthetic PC metabolism with specificity for the transmembrane choline transporter and choline kinase [12, 13]. Consequently, the tissue concentration of PC, rather than total choline, may correlate best with FCH uptake. The relationship between PC and GPC metabolism under some tumor conditions has been studied. For example, activation of phospholipase can decrease PC and increase GPC levels in breast and prostate cancer cells, potentially leading to a less aggressive phenotype [11, 14]. Exposure to chemotherapeutic agents can also decrease tissue levels of PC while increasing the levels of GPC [15, 16]. These results suggest the possibility of assessing tumor therapeutic response through specific measurement of PC or GPC metabolism.We look forward to future studies comparing FCH PET to other methods for measuring PC metabolism in vivo.

The Antibacterial Cell Division Inhibitor PC190723 Is an FtsZ Polymer-stabilizing Agent That Induces Filament Assembly and Condensation

Cell division protein FtsZ can form single-stranded filaments with a cooperative behavior by self-switching assembly. Subsequent condensation and bending of FtsZ filaments are important for the formation and constriction of the cytokinetic ring. PC190723 is an effective bactericidal cell division inhibitor that targets FtsZ in the pathogen Staphylococcus aureus and Bacillus subtilis and does not affect Escherichia coli cells, which apparently binds to a zone equivalent to the binding site of the antitumor drug taxol in tubulin (Haydon, D. J., Stokes, N. R., Ure, R., Galbraith, G., Bennett, J. M., Brown, D. R., Baker, P. J., Barynin, V. V., Rice, D. W., Sedelnikova, S. E., Heal, J. R., Sheridan, J. M., Aiwale, S. T., Chauhan, P. K., Srivastava, A., Taneja, A., Collins, I., Errington, J., and Czaplewski, L. G. (2008) Science 312, 1673-1675). We have found that the benzamide derivative PC190723 is an FtsZ polymer-stabilizing agent. PC190723 induced nucleated assembly of Bs-FtsZ into single-stranded coiled protofilaments and polymorphic condensates, including bundles, coils, and toroids, whose formation could be modulated with different solution conditions. Under conditions for reversible assembly of Bs-FtsZ, PC190723 binding reduced the GTPase activity and induced the formation of straight bundles and ribbons, which was also observed with Sa-FtsZ but not with nonsusceptible Ec-FtsZ. The fragment 2,6-difluoro-3-methoxybenzamide also induced Bs-FtsZ bundling. We propose that polymer stabilization by PC190723 suppresses in vivo FtsZ polymer dynamics and bacterial division. The biochemical action of PC190723 on FtsZ parallels that of the microtubule-stabilizing agent taxol on the eukaryotic structural homologue tubulin. Both taxol and PC190723 stabilize polymers against disassembly by preferential binding to each assembled protein. It is yet to be investigated whether both ligands target structurally related assembly switches.

Analyses for phosphatidylcholine hydroperoxides by LC/MS

A new liquid chromatography mass spectrometry (LC/MS) method has been developed for the qualitative and quantitative analyses of phosphatidylcholine hydroperoxides (PC-OOH) in human plasma using a synthetic hydroperoxide (1-stearoyl-2-erucoyl-PC monohydroperoxide, PC 18:0/22:1-OOH) as an internal standard. 1-Stearoyl-2-linoleoyl-PC monohydroperoxide (PC 18:0/18:2-OOH) was identified in plasma by LC/MS by comparison with an authentic standard. The calibration curves obtained for 1-palmitoyl-2-linoleoyl-PC monohydroperoxide, PC 16:0/18:2-OOH and PC 18:0/18:2-OOH were linear throughout the calibration range (0.1–1.0 pmol). The limit of detection (LOD) (S/N = 3:1) was 0.01 pmol, and the limit of quantification (LOQ) (S/N = 6:1) was 0.1 pmol for both PC 16:0/18:2-OOH and PC 18:0/18:2-OOH. Plasma concentrations of PC 16:0/18:2-OOH and PC 18:0/18:2-OOH were 89 and 32 nM, respectively, in a healthy volunteer.

A novel application of 1H magnetic resonance spectroscopy: non-invasive identification of spermatogenesis in men with non-obstructive azoospermia

About 10% of infertile men have no sperm in their ejaculate due to poor or absent spermatogenesis, also known as non-obstructive azoospermia (NOA). Testis (1)H magnetic resonance spectroscopy ((1)H-MRS) is a non-invasive imaging tool that can potentially identify and localize spermatogenesis in the testis. This study sought to identify metabolic signatures associated with various histological states of spermatogenesis in infertile men. Quantitative high resolution magic angle spinning spectroscopy was performed on snap frozen testicular tissue from 27 men with three classic histological patterns: (i) normal spermatogenesis (men with prior paternity undergoing vasectomy reversal), (ii) maturation arrest (early or late, MA) or (iii) Sertoli-cell only (SCO). Concentrations of 19 tissue metabolites were acquired from each biopsy specimen. One-way ANOVA analysis was used to determine inter-group differences in metabolite concentrations among the three histologic groups. Phosphocholine (PC) and taurine tissue concentrations were significantly different between normal and SCO tissue. Mean PC concentrations were three times higher in normal testes compared with SCO (5.4 +/- 1.4 versus 1.5 +/- 0.3 mmol/kg; P = 0.01). No differences in metabolite concentrations were observed between normal and MA testes or between SCO and MA testes. Further histologic stratification of MA testes into subsets of those with (early) and without (late) spermatids or mature sperm, identified differences in PC concentrations. A predictive model for sperm presence with (1)H-MRS was developed based upon PC tissue concentrations. PC concentrations are significantly higher in testes with spermatogenesis. This suggests that a unique metabolic signature for spermatogenesis is possible using (1)H-MRS which could aid in the non-invasive diagnosis of sperm in men with NOA.