Fresh Suspensions Research Articles

The metabolism of carbamazepine in fresh rodent hepatocyte suspensions: The effect of bromine substitution on metabolism

The metabolism of carbamazepine in fresh rodent hepatocyte suspensions: The effect of bromine substitution on metabolism

Ear secondary traits related to aflatoxin accumulation in commercial maize hybrids under artificial field inoculation

Aims of the research were: (1) to evaluate and compare 24 maize hybrids for Aspergillus flavus resistance and for aflatoxin accumulation under artificial inoculation in field experiments grown during 2005 and 2006; (2) to estimate the relationship of aflatoxin concentration with ear secondary traits. Primary ears were inoculated with a fresh spore suspension (mixture of five A. flavus isolates from Northern Italy), by spraying silks, as a modification of the non-wounding silk channel inoculation technique (SCIA); controls were both non-inoculated and sterile water-inoculated ears. Ear secondary traits, such as silk channel length measured at pollination and husk coverage at maturity, were recorded for each hybrid. The severity of ear A. flavus attack was estimated using rating scales based on the percentage of kernels with visible symptoms of infection. The aflatoxin concentration in the inoculated ears resulted, during both years, higher than in the controls; this indication confirmed that the A. flavus isolates used for the inoculum procedure were successful in accumulating mycotoxin in grains. Variability was found among the hybrids under study: aflatoxin accumulation, after artificial inoculation, ranged from 0.13 to 705.25 ng/g. The data herein presented supported the implication of two ear secondary traits in determining aflatoxin accumulation. Silk channel length recorded at pollination was negatively correlated (r = -0.54; P<0.05) with aflatoxin accumulation; on the contrary, a positive correlation (r = 0.48; P<0.05) between husk coverage rating at maturity and aflatoxin concentration suggested that a looser husk coverage is associated with higher aflatoxin accumulation. The correlation between the two mentioned ear-related traits was negative (r = -0.73; P<0.05); this indicated that hybrids showing a good coverage at pollination stage, are favoured in keeping the ear tip covered until maturity, reducing the risk of aflatoxin accumulation.

Evaporative Deposition of Bacteria from a Sessile Drop: Effects of Suspension Aging

AbstractIn this work, we report on the evaporative deposition of bacteria from a drying aqueous drop on mica as a function of the bacterial suspension age. For sufficiently aged bacterial suspensions, residues are small and more filled-in than residues formed from fresh suspensions on similarly aged mica. In addition, the interior deposition pattern transitions from a cellular film characteristic of fresh suspensions to a cracked carpet pattern for aged suspensions. Suspension aging related changes in the residues are attributed to accumulation of organic materials such as DNA, RNA, proteins, and other bacterial components in the suspension. The aging process is also observed to be at least partially dependent on ventilation of the suspension during aging.

Effect of Cryopreservation on Nitric Oxide Production by Stallion Spermatozoa1

The ability of stallion spermatozoa to produce nitric oxide (NO) before (fresh) and after freezing and thawing (FT) was evaluated by means of flow cytometry after loading the sperm suspension with the probe, 4,5-diaminofluorescenin diacetate. The presence of NO synthase (NOS) was investigated by Western blotting using anti-NOS1, anti-NOS3, or anti-universal NOS antibodies (Abs). While NO was detected both in fresh and FT sperm suspensions, its production increased after cryopreservation only when egg yolk was removed from the extender. Anti-NOS1 Ab intensively labeled a single band with an apparent molecular mass of approximately 83 kDa. On the other hand, the Ab developed against the NOS3 showed a band of approximately 96 kDa in fresh and FT sperm lysates. NO production was positively correlated with sperm motility and velocity after thaw, suggesting an NO role for the functionality of cryopreserved stallion spermatozoa; but the production of NO is compromised in egg yolk-containing extenders.

Effect of Various Platelet Preparations on Retinal Müller Cells

Peeling of the internal limiting membrane is the treatment of choice for macular holes. Fresh platelet suspension (PS) is used to support wound healing in persistent macular holes. The concentration of growth factors in fresh, frozen, and thrombin-activated PSs were compared, to optimize their trophic potential and examine their capacity to support proliferation, migration, and contraction of human retinal Müller cells. The concentration of various growth factors in frozen PS, thrombin-activated PS, and plasma were evaluated by ELISA. The effect of these preparations on proliferation, migration, and contraction of human Müller cells were evaluated with an ATP-assay, a colony-dispersion assay, and a detached collagen gel contraction assay respectively. Plasma was tested as a control. Frozen and thrombin-activated PSs contained significantly more EGF, TGF-beta1, and PDGF than did plasma. The highest concentrations of EGF and FGF were found in frozen PS. All platelet preparations and plasma supported cell growth significantly better than the control, which was serum-free culture medium. Müller cells migrated better when incubated with thrombin-activated PS than with any other test solution. Contraction was extremely strong after incubation with fresh PS compared with plasma or thrombin-activated or frozen PSs. Frozen and thrombin-activated PSs may be suitable alternatives to fresh PS for persisting macular holes, due to their superior effect on Müller cell migration.

First Record of Oidiopsis taurica Causing Powdery Mildew of Capparis spinosa in Egypt.

Powdery mildew infections were observed on Capparis spinosa plants in Wadi El-Arbaein, Saint Katherine Protectorate, Egypt (28°32'43.1″N, 33°57'81″E, altitude 1,663 m) in the early fall to the end of winter of 2007 and 2008 when temperatures vary from the lowest mean value of 2.8°C to the highest mean value of 26.5°C. Symptoms first appeared as white, circular patches on the adaxial leaf surface (<1.3 cm in diameter), and as the disease progressed, both leaf surfaces were infected and these chlorotic areas eventually turned to necrotic lesions. Light microscopy revealed that the disease was caused by the anamorph stage of a powdery mildew fungus. Mycelium is predominantly endophytic with the presence of conidiophores emerging through leaf stomata. Conidiophores were simple or branched one or two times at random positions, 55 to 140 × 4.5 to 6 μm, producing conidia singly, and followed by two to three straight cells. Primary conidia were pyriform (68.9 × 18.5 μm) with a tapering end while secondary conidia were more cylindrical (59.1 × 18.0 μm). Mature conidia were hyaline, without distinct fibrosin bodies, and with angular/reticulated wrinkling of the outer walls. On the basis of these characteristics, the causal agent was identified as Oidiopsis taurica (1,3). The teleomorphic stage of the fungus was not observed. Pathogenicity tests were performed by inoculating three, potted, healthy C. spinosa plants with a fresh conidial suspension collected from powdery mildew colonies found on the infected plants (1 × 104 conidia/ml) under the same field conditions. After 15 to 17 days, symptoms and signs of powdery mildew developed on the foliage of inoculated plants. Herbarium specimens of C. spinosa leaves infected with O. taurica were deposited at the Herbarium of Botany Department (SCU), Faculty of Science, Suez Canal University, Egypt. To our knowledge, this is the first record of a powdery mildew disease on C. spinosa in Egypt. Recently, Leveillula taurica, the teleomorph stage of O. taurica, was reported from C. spinosa in Turkey (2).

Adsorption-membrane filtration process in boron removal from first stage seawater RO permeate

The paper deals with evaluation of adsorption-membrane filtration (AMF) hybrid process in removal of trace amounts of boron from the first stage RO permeate. Finely ground boron selective resin, Dowex XUS 43594.00, was used as sorbent while polypropylene capillaries with pore dimension of 0.4 μm as the submerged membranes. The process combined delivery of feed and fresh resin suspension with subsequent removal of the loaded sorbent. The effects of such process variables were evaluated: diameter of resin bead, concentration of suspension, rate of suspension replacement and time of the system run. It was found that to reduce boron concentration from 2 mg/L to the WHO recommended level, 1 g/L of resin should be used. During 48 h of process, neither membranes fouling by the sorbent particles nor sedimentation of resin was observed. When resin was subjected to regeneration particle diameter was not changed after 20 alternating immersions in acidic and basic solutions.

Film coating of seeds with Bacillus cereus RS87 spores for early plant growth enhancement

The plant growth-promoting rhizobacterium Bacillus cereus RS87 was previously reported to promote plant growth in various crops in both greenhouse and field trials. To apply as a plant growth promoting agent with practical use, it is essential to ease the burden of routine preparation of a fresh suspension of strain RS87 in laboratory. The objectives of this study were to investigate the feasibility of film-coating seeds with B. cereus RS87 spores for early plant growth enhancement and to reveal the indoleacetic acid (IAA) production released from strain RS87. The experiment consisted of the following 5 treatments: nontreated seeds, water-soaked seeds, film-coated seeds, seeds soaked with vegetative cells of strain RS87, and film-coated seeds with strain RS87 spores. Three experiments were conducted separately to assess seed emergence, root length, and plant height. Results showed that both vegetative cells and spores of strain RS87 significantly promoted (P < or = 0.05) seed emergence, root length and plant height over the control treatments. The strain RS87 also produced IAA. In conclusion, the film coating of seeds with spores of B. cereus RS87 demonstrated early plant growth enhancement as well as seeds using their vegetative cells. IAA released from strain RS87 would be one of the mechanisms for plant growth enhancement.

CO2 Sequestration Potential of Steel Slags at Ambient Pressure and Temperature

A study of carbon dioxide sequestration has been performed in aqueous electric arc furnace (EAF) and ladle furnace (LF) slag suspensions, in leached hydrated-matrixes, and in leachates to estimate their intrinsic sequestration potential at ambient conditions (temperature of 20 ± 1 °C and atmospheric pressure). The CO2 sequestration was tested in aqueous suspensions of steel slags at a liquid-to-solid ratio of 10 kg/kg as well as in leached hydrated-matrixes and leachates isolated from these fresh slag suspensions after three consecutive leachings. The sequestration assays were performed at 20 °C with a flow rate of 5 mL/min of a CO2 concentration of 15.00 vol %. The results have revealed that the CO2 sequestration capacity of the LF slag suspension (24.7 g of CO2/100 g of slag) is 14 times superior to that of the EAF slag suspension. This greater CO2 sequestration capacity of the LF slag suspension may be associated in large part to its higher content of portlandite, which reacts with CO2 relative to the ...

CO2 Sequestration by Aqueous Red Mud Carbonation at Ambient Pressure and Temperature

An analysis of carbonation was carried out with the aqueous fresh red mud suspension at a liquid-to-solid ratio of 10 kg/kg, as well as in the leached-hydrated matrixes and leachates isolated from this red mud suspension after three successive leachings, to evaluate their intrinsic carbonation potential at ambient conditions (temperature of 20 ± 1 °C and atmospheric pressure). The carbonation assays were performed at 20 °C using a CO2 concentration of 15.00 vol% at a flow rate of 5 mL/min. The red mud matrix has a great leaching capacity of Na−(hydr)oxide, which is the principal hydroxide that seems to be implicated in the carbonation of leachates that have half-carbonation capacity of red mud. Moreover, the carbonation of the red mud suspension also involves a portlandite-containing matrix. The carbonation of the red mud suspension and leachates implicates a complete neutralization of their content in Ca− and Na−(hydr)oxides. Although the leached hydrated-matrixes seem to be partially carbonated, it preserves a carbonation capacity near to that of leachate after three successive leachings. Moreover, three leached hydrated-matrixes and leachates have a carbonation capacity (7.09 g of CO2/100 g of red mud) higher than the carbonation capacity obtained for the red mud suspension, which is evaluated to 4.15 g of CO2/100 g of red mud. Taken together, these results suggest that the carbonation of the red mud may be enhanced by the use of leached hydrated-matrixes and leachates obtained from multiple leaching.

Stability of concentrated suspensions of Al 2O 3–SiO 2 measured by multiple light scattering

The stability of ceramic suspensions can be predicted by means of zeta potential and particle size measurements but a major problem is that most existing techniques make use of diluted suspensions so that the concentrated suspensions frequently used in shape forming of ceramics are out of range. The propagation of light through a concentrated suspension can be used to characterise its colloidal stability. This work aims to study the variations of the structure of concentrated ceramic suspensions maintained at rest by multiple light scattering (MLS). This technique allows us to obtain information about the agglomeration processes that take place during ageing, like particle migration and particle aggregation. The results are compared with those obtained using conventional techniques such as the predictive tests (e.g. zeta potential and rheological behaviour of fresh suspensions) and ageing studies measured by rheometry. For such purpose, aqueous suspensions of alumina and alumina/silica (used to produce mullite by reaction sintering) have been studied.

Decontamination of Root Canals with the Gallium-Aluminum-Arsenide Laser: Anin VitroStudy

In this in vitro study, we investigated the bactericidal effects on root canals of 810-nm diode laser irradiation, alone or combined with sodium hypochlorite and citric acid irrigation. One hundred sixteen single-rooted human teeth extracted for periodontal reasons were randomly divided into four experimental groups. The canal of each tooth was prepared with a conventional step-back technique and a pure culture of vancomycin-resistant Enterococcus faecalis grown in brain heart infusion broth was used to contaminate the root canal. The specimens were incubated at 37 degrees C for 15 d in a test tube filled with agar, adding fresh bacterial suspension every 48 h, and sent them for microbiological analysis and bacterial count. Subsequently they were divided into four groups: in group A, 29 teeth were irrigated with 2 mL of 10% citric acid solution; in group B, 29 teeth were irrigated with 2 mL 5.25% sodium hypochlorite (NaOCl) solution; in group C, 29 teeth were irradiated with 810-nm laser energy via a 200-microm optic fiber at 2.5 W power in pulsed mode (10 msec on and 10 msec off) for 5 sec; and in group D, 29 teeth were irrigated with NaOCl, irradiated with the laser, then irrigated with citric acid, and irradiated with the laser, followed again by NaOCl irrigation and laser irradiation. All the samples were again sent for microbiological analysis and bacterial count. Group A had a bactericidal effect of 0.041 log mean CFU, that of group B was 3.381 log mean CFU, and that of group C was 1.459 log mean CFU, whereas group D showed the best results, with a bactericidal effect of 7.178 log mean CFU. The use of NaOCl, citric acid, and diode laser energy together have a synergistic effect, increasing treatment efficacy and leading to significantly better decontamination of the root canal.

DNA and DNAzyme-Mediated 2D Colloidal Assembly

DNA-mediated interactions present a significant opportunity for controlling colloidal self-assembly. Using microcontact printing to achieve spatial control of DNA-surface patterning and DNA-functionalized polystyrene colloids, we report that DNA hybridization can be utilized for sequence-specific reversible self-assembly of well-ordered 2D colloidal arrays. Two essential indicators of DNA-hybridization mediated assembly were confirmed: thermal reversibility and sequence specificity. The arrays melted at 50 degrees C and reassembled when introduced to fresh colloid suspension, and sequence specificity with <1% nonspecific binding was confirmed using fluorescent polystyrene colloids. The real-time assembly of the colloids onto the periodically patterned substrate was monitored by simple laser diffraction to obtain assembly kinetics. Maximum surface coverage of DNA-mediated assembly was determined to be 0.593 for DNA-functionalized 100 nm polystyrene colloids, and 90% of the assembly was complete after 6.25 h of hybridization in 50 mM NaCl Tris buffer. We also demonstrate that DNAzymes, catalytic DNA molecules, can be incorporated into the design, and in the presence of 10 microM Pb(2+), the hybridization-induced array assembly can be disrupted via DNAzyme activity.

Comparison of Two Different Methods for Inoculating VX2 Tumors in Rabbit Livers and Hind Limbs

To compare two methods to (a) propagate VX2 cell strain in rabbit hind limbs and (b) inoculate liver parenchymal tumors in rabbits.One hundred forty-two New Zealand white rabbits were used for this study (60 with hind limb tumor [donors] and 82 with liver tumors [recipients]). In the donor group, nine rabbits received frozen VX2 cell suspension and 51 were injected with freshly prepared VX2 cell suspension. In the recipient group, 32 rabbits were injected with VX2 tumor cells and 50 were implanted with a small tumor fragment in the liver parenchyma. Success rates in terms of tumor growth were compared by using chi(2) or Fisher exact tests, with alpha = .05.Hind limb and liver tumors were successfully grown in 48 of the 60 rabbits in the donor group (80%) and 57 of the 82 rabbits in the recipient group (70%). The success rate of growing hind limb tumors increased from 33% (three of nine rabbits) to 88% (45 of 51 rabbits) when fresh VX2 cells instead of frozen were injected percutaneously (P < .0011). Similarly, the success rate for VX2 liver tumors almost doubled from 47% (15 of 32 rabbits) to 84% (42 of 50 rabbits) when a tumor fragment instead of VX2 cell suspension was used (P < .00036). This also significantly reduced the frequency of metastasis (P < .005).The authors recommend (a) the use of fresh VX2 cell suspension for percutaneous injection in the hind limbs of rabbits to maintain the VX2 cell strain and (b) the surgical implantation of freshly harvested VX2 tumor fragment into the liver parenchyma to establish liver tumors.

Bio-optical properties of the marine cyanobacteria Trichodesmium spp.

Bio-optical spectral properties were determined on fresh suspensions of Trichodesmium spp. collected in a tropical lagoon and put in seawater tanks (total chlorophyll concentrations range between 0.1 and 3.8 mg m -3 ). The spectrum of the backscattering coefficient was a hyperbolic function with a slope of 1.2, often showing troughs at 440, 550 and 676 nm, due to absorption peaks of chlorophyll and phycoerythrin. The absorption spectrum computed with a specific beta correction for Trichodesmium, showed a blue to red ratio (B/R) equivalent to the one of a single colony (B/R=2), and also showed the double peak of mycosporine-like amino acids (MAA's, 330 and 360 nm). The CDOM absorption spectrum showed minor MAA peaks when cyanobacterial concentrations were above 1 mg Chl a m -3 . The chlorophyll a-specific backscattering and absorption coefficients at 442 nm were respectively 0.0126 m

Antimicrobial action and efficiency of silver-loaded zeolite X

To synthesize silver-loaded zeolite X and establish the extent to which it persist in its antimicrobial action against strains of Escherichia coli K12W-T, Pseudomonas aeruginosa NCIMB8295 and Staphylococcus aureus NCIMB6571. The antimicrobial action and efficacy of silver-loaded zeolite X on Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa were investigated. Zeolite X was synthesized and loaded with Ag(+) by ion exchange. This resulted in 2.0% (w/w) loading of Ag(+) in the zeolite framework and 5.8% (w/w) on the zeolite. Escherichia coli and Pseudomonas aeruginosa and Staphylococcus aureus suspended in tryptone soya broth were exposed to 0.15, 0.25, 0.5 or 1.0 g l(-1) of silver-loaded zeolite X for a period up to 24 h. No viable cells were detected for any of the three micro-organisms within 1 h. Silver-loaded zeolite X, retrieved three times from the first exposure cultures, was washed with de-ionized water and added to fresh bacterial suspensions. The results showed that the silver-loaded zeolite X retained its antimicrobial action. Silver-loaded zeolite X persisted in its antimicrobial action against all three micro-organisms. The results are significant for the longevity of antimicrobial action of silver-loaded zeolite X.

Fluvastatin potentiates the activity of caspofungin against Aspergillus fumigatus in vitro

Statins (anticholesterol drugs) inhibit HMG-CoA reductase, which is a key rate-limiting enzyme in the synthesis of sterols in fungi. We therefore investigated the in vitro inhibitory activity of various statins against Aspergillus fumigatus alone and in combination with antifungal drugs. Fresh conidial suspensions from 10 clinical isolates of A. fumigatus were obtained. The MIC and minimum fungicidal concentration (MFC) were determined by the Clinical and Laboratory Standards Institute M-38A protocol and the fungicidal activity by time–kill study. Fluvastatin (FST) showed good activity (MIC, 2 mg/L; MFC, 4 mg/L) against A. fumigatus; other statins had no activity (MIC ≥256 mg/L). FST enhanced the activity of caspofungin (CFG) against A. fumigatus; subinhibitory concentrations of FST in combination with CFG showed >99.9% killing of A. fumigatus conidia, whereas either drug alone showed poor activity at subinhibitory concentrations. FST potentiated the antifungal activity of CFG but displayed no specific interaction with voriconazole or amphotericin B.

Characterization of the Metabolic Activation of Hepatitis C Virus Nucleoside Inhibitor β-d-2′-Deoxy-2′-fluoro-2′-C-methylcytidine (PSI-6130) and Identification of a Novel Active 5′-Triphosphate Species

beta-D-2'-Deoxy-2'-fluoro-2'-C-methylcytidine (PSI-6130) is a potent inhibitor of hepatitis C virus (HCV) replication in the subgenomic HCV replicon system, and its corresponding 5'-triphosphate is a potent inhibitor of the HCV RNA polymerase in vitro. In this study the formation of PSI-6130-triphosphate was characterized in primary human hepatocytes. PSI-6130 and its 5'-phosphorylated derivatives were identified, and the intracellular concentrations were determined. In addition, the deaminated derivative of PSI-6130, beta-d-2'-deoxy-2'-fluoro-2'-C-methyluridine (RO2433, PSI-6026) and its corresponding phosphorylated metabolites were identified in human hepatocytes after incubation with PSI-6130. The formation of the 5'-triphosphate (TP) of PSI-6130 (PSI-6130-TP) and RO2433 (RO2433-TP) increased with time and reached steady state levels at 48 h. The formation of both PSI-6130-TP and RO2433-TP demonstrated a linear relationship with the extracellular concentrations of PSI-6130 up to 100 mum, suggesting a high capacity of human hepatocytes to generate the two triphosphates. The mean half-lives of PSI-6130-TP and RO2433-TP were 4.7 and 38 h, respectively. RO2433-TP also inhibited RNA synthesis by the native HCV replicase isolated from HCV replicon cells and the recombinant HCV polymerase NS5B with potencies comparable with those of PSI-6130-TP. Incorporation of RO2433-5'-monophosphate (MP) into nascent RNA by NS5B led to chain termination similar to that of PSI-6130-MP. These results demonstrate that PSI-6130 is metabolized to two pharmacologically active species in primary human hepatocytes.

The evaluation of an in vitro fresh suspension hepatocyte model in the investigation of drug-induced hepatotoxicity

The evaluation of an in vitro fresh suspension hepatocyte model in the investigation of drug-induced hepatotoxicity

Forskolin stimulates phosphorylation and membrane accumulation of UT-A3

UT-A1 is regulated by vasopressin and is localized to the apical membrane and intracellular compartment of inner medullary collecting duct (IMCD) cells. UT-A3 is also expressed in the IMCD and is regulated by forskolin in heterologous systems. The goal of the present study is to investigate mechanisms by which vasopressin regulates UT-A3 in rat IMCD. In fresh suspensions of rat IMCD, forskolin increases the phosphorylation of UT-A3, similar to UT-A1. Biotinylation studies indicate that UT-A3 is located in the plasma membrane. Forskolin treatment increases the abundance of UT-A3 in the plasma membrane similar to UT-A1. However, these two transporters do not form a complex through a protein-protein interaction, suggesting that transporter function is unique to each protein. While immunohistochemistry localized UT-A3 to the basal and lateral membranes, a majority of the staining was cytosolic. Immunohistochemistry of vasopressin-treated rat kidney sections also localized UT-A3 primarily to the cytosol with basal and lateral membrane staining but also showed some apical membrane staining in some IMCD cells. This suggests that under normal conditions, UT-A3 functions as the basolateral transporter but in a high cAMP environment, the transporter may move from the cytosol to all plasma membranes to increase urea flux in the IMCD. In summary, this study confirms that UT-A3 is located in the inner medullary tip where it is expressed in the basolateral membrane, shows that UT-A3 is a phosphoprotein in rat IMCD that can be trafficked to the plasma membrane independent of UT-A1, and suggests that vasopressin may induce UT-A3 expression in the apical plasma membrane of IMCD.